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diff --git a/old/44526.txt b/old/44526.txt new file mode 100644 index 0000000..933c348 --- /dev/null +++ b/old/44526.txt @@ -0,0 +1,60317 @@ +The Project Gutenberg eBook, Report on the Radiolaria Collected by H.M.S. +Challenger During the Years 1873-1876, Second Part: Subclass Osculosa; +Index, by Ernst Haeckel + + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + + + + +Title: Report on the Radiolaria Collected by H.M.S. Challenger During the Years 1873-1876, Second Part: Subclass Osculosa; Index + Report on the Scientific Results of the Voyage of H.M.S. Challenger During the Years 1873-76, Vol. XVIII + + +Author: Ernst Haeckel + + + +Release Date: December 28, 2013 [eBook #44526] + +Language: English + +Character set encoding: ISO-646-US (US-ASCII) + + +***START OF THE PROJECT GUTENBERG EBOOK REPORT ON THE RADIOLARIA COLLECTED +BY H.M.S. CHALLENGER DURING THE YEARS 1873-1876, SECOND PART: SUBCLASS +OSCULOSA; INDEX*** + + +E-text prepared by Charlene Taylor, Adrian Mastronardi, Keith Edkins, and +the Online Distributed Proofreading Team (http://www.pgdp.net) from page +images generously made available by Internet Archive (https://archive.org) + + + +Note: Images of the original pages are available through + Internet Archive. See + https://archive.org/details/reportonradiolar02haecrich + + Project Gutenberg has the other two parts of this work. + First Part: First Part: Porulosa (Spumellaria and Acantharia) + see http://www.gutenberg.org/ebooks/44525. + Plates + see http://www.gutenberg.org/ebooks/44527. + + +Transcriber's note: + + Text enclosed by underscores is in italics (_Actissa_). + + The underscore also denotes a subscript, so _c__1 is an + italic c with a subscript (note that there are two + underscoreds between the "c" and the "1"). + + Text enclosed by hash marks is in "gesperrt" + (wide-spaced) type (#Larcoidea#). + + Page numbers enclosed by curly braces (example: {25}) have + been incorporated to facilitate the use of the Index. + + Some typographical errors in the printed work have been + corrected. They are listed at the end of the text. + + The Addenda & Errata (Second Part, pp. 1763-4) have been + applied without further comment. + + + + + +REPORT ON THE SCIENTIFIC RESULTS OF THE VOYAGE OF H.M.S. CHALLENGER +DURING THE YEARS 1873-76 + +Under the Command of Captain George S. Nares, R.N., F.R.S. +and the Late Captain Frank Tourle Thomson, R.N. + +Prepared Under the Superintendence of +the Late Sir C. Wyville Thomson, KNT., F.R.S., &c. +Regius Professor of Natural History in the University of Edinburgh +Director of the Civilian Scientific Staff on Board +and Now of +John Murray +One of the Naturalists of the Expedition + +ZOOLOGY--VOL. XVIII. + +SECOND PART + +Published by Order of Her Majesty's Government + + + + + + + +Printed for Her Majesty's Stationary Office +and Sold by +London:--Eyre & Spottiswoode, East Harding Street, Fetter Lane +Edinburgh:--Adam & Charles Black +Dublin:--Hodges, Figgis, & Co. +1887 + +Price (in Two Parts, with a Volume of Plates) L5, 10s. + + + + +CONTENTS. + + + + +REPORT on the RADIOLARIA collected by H.M.S. CHALLENGER during the years +1873-1876. + +By ERNST HAECKEL, M.D., Ph.D., Professor of Zoology in the University of +Jena. + +SECOND PART.--OSCULOSA. + +(#NASSELLARIA AND PHAEODARIA.#) + + + + +CONTENTS. + + + + SECOND PART. + + II. Subclass OSCULOSA, 889 + Legion III. NASSELLARIA vel MONOPYLEA, 889 + Order 11. Nassoidea, 895 + " 12. Plectoidea, 898 + " 13. Stephoidea, 931 + " 14. Spyroidea, 1015 + " 15. Botryodea, 1103 + " 16. Cyrtoidea, 1126 + + Legion IV. PHAEODARIA vel CANNOPYLEA, 1521 + Order 17. Phaeocystina, 1542 + " 18. Phaeosphaeria, 1590 + " 19. Phaeogromia, 1642 + " 20. Phaeoconchia, 1710 + + Note on the Dimensions and Measurements, 1760 + + ADDENDA, 1761 + + ERRATA, 1763 + + INDEX, 1765 + + + + +{889}LEGION III. NASSELLARIA, + +VEL MONOPYLEA, VEL MONOPYLARIA (PLS. 51-98). + + _Nassellaria_ (_inclusis_ Spyridinis), Ehrenberg, 1875. + _Monopylea_, Hertwig, 1879. + _Monopylaria_, Haeckel, 1881. + _Cyrtida_ et _Acanthodesmida_, Haeckel, 1862. + _Cricoidea_, Buetschli, 1882 (L. N. 40, p. 537) = NASSELLARIA. + +_Definition._--Radiolaria with simple membrane of the central capsule, +which is monaxon or bilateral, and bears on one pole of the main axis a +porous area (porochora), forming the base of a peculiar intracapsular cone +(podoconus). Extracapsulum without phaeodium. Skeleton siliceous, very +rarely wanting. Fundamental form originally monaxon, often dipleuric or +bilateral. + +The legion NASSELLARIA vel MONOPYLEA, in the extent here defined, was +constituted in 1879 by Richard Hertwig in his work Der Organismus der +Radiolarien (pp. 133-137). He gave to this large group the rank of an +order, and united in it the two families Acanthodesmida and Cyrtida, which +I had constituted first in 1862 in my Monograph (pp. 237, 265, 272); but he +added, too, as a third family the Plagiacanthida, united by me with the +former. In the first system of Ehrenberg (1847, _loc. cit._, pp. 53, 54), +four families belonging to the MONOPYLEA were enumerated, the +Halicalyptrina, Lithochytrina, Eucyrtidina, and Spyridina. He united the +three former under the name "Polycystina solitaria," which he afterwards +changed into NASSELLARIA (1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. +157). + +In my Monograph of the Radiolaria (1862, pp. 265-345) forty-four genera of +NASSELLARIA were enumerated (six Acanthodesmida and thirty-eight Cyrtida), +whilst the total number of genera in the whole class of Radiolaria at that +time amounted to one hundred and thirteen. But owing to the astonishing +number of new and interesting forms of this legion which I afterwards +detected in the collection of the Challenger, in 1881 I distinguished in my +Prodromus not less than three hundred and seventeen genera. These were +disposed in five large main groups, retained in the present Report, with +twenty-six families, viz., (1) #Plectoidea# (with three families), (2) +#Stephoidea# (with four families), (3) #Spyroidea# (with four families), +(4) #Botryodea# (with three families), and (5) #Cyrtoidea# (with twelve +families). The first two groups have an incomplete or rudimentary skeleton, +and may be united in the order #Plectellaria#, whilst the other three +families possess a complete latticed shell, and {890}may be united as +#Cyrtellaria#. The former correspond to the Acanthodesmida, the latter to +the Cyrtida in my Monograph. + +The character common to all MONOPYLEA or NASSELLARIA, which separates them +from all other Radiolaria, was first recognised by Richard Hertwig in 1879, +and consists in the singular structure of the monaxonian central capsule, +bearing on the basal pole a peculiar porous area or operculum, the +"Porenfeld;" we call it shortly the "porochora." It represents a circular +or elliptical porous plate on the basal pole of the vertical main axis of +the central capsule, and bears a peculiar "podoconus" or +"Pseudopodien-Kegel," a conical body of singular structure, protruding +inside the membrane into the capsule. The pseudopodia arising from this +peculiar "podoconus" proceed from the capsule piercing the "porochora," +whilst the other parts of the capsule are not perforated. + +The MONOPYLEA are therefore "Merotrypasta," like the following fourth +legion, the PHAEODARIA or CANNOPYLEA. But in these latter we find on the +basal pole of the monaxonian capsule only one single large main opening, +prolonged into a peculiar tube, and there is no trace of the typical +"podoconus," characteristic of all NASSELLARIA. The latter agree, however, +with the former in the possession of a basal opening, serving for the +emission of the pseudopodia, and in the monaxonian fundamental form, +arising from this structure. Therefore these two legions of "Merotrypasta" +exhibit a wider divergence from the ACANTHARIA and SPUMELLARIA, the two +legions of "Holotrypasta," in which the central capsule is everywhere +perforated by innumerable small pores (compare above, pp. 5, 6, 716). + +_The Skeleton_ in all NASSELLARIA consists either of pure silica, or of a +peculiar silicate; never of acanthin (as in all ACANTHARIA). The siliceous +bars and beams constituting it are invariably solid (as also in the +SPUMELLARIA); never hollow (as in the PHAEODARIA). In the small family of +Nassellida alone (with the two genera _Cystidium_ and _Nassella_) the +skeleton is entirely absent. In all other genera of NASSELLARIA the +siliceous skeleton is more or less developed; imperfect, or quite +rudimentary in the #Plectellaria# (#Plectoidea# and #Stephoidea#), but +perfect and forming a regular lattice-shell in the #Cyrtellaria# +(#Spyroidea#, #Botryodea#, and #Cyrtoidea#). The different forms of this +skeleton exhibit an extraordinary variety, but may be reduced to a few very +simple fundamental forms, or even to a single, most simple original form. +The comparative morphology is more interesting, but also more difficult to +understand than in any other Radiolaria. + +The geometrical fundamental form of the skeleton is in all NASSELLARIA +monaxonial, the vertical main axis of the body, which is already indicated +by the axis of the central capsule with two different poles, being also +expressed constantly in the form of the skeleton. The lower or basal pole +of the latter always exhibits a different shape from that of the upper or +apical pole. This difference is so striking in nearly all MONOPYLEA, that +the two poles may be determined on the first view. + +{891}In the great majority of NASSELLARIA not only is the monaxonial +fundamental form expressed, but also the dipleuric or bilateral, so that +the symmetrical halves of the body may be easily determined; the right and +left halves exhibit the same symmetry as in the vertebrates, so that we may +distinguish an anterior ventral and a posterior dorsal face of the body. +The whole form is in this case determined by three dimensive axes, +perpendicular to one another, two of which are heteropolar, the third is +homoeopolar. The apical pole of the vertical main axis (principal or +longitudinal axis) is different from the basal pole. The ventral pole of +the horizontal sagittal axis (or dorso-ventral axis) is different from the +dorsal pole. The right pole of the horizontal transverse axis (lateral or +frontal axis) is equal to the left pole. Therefore the sagittal or median +plane of the body (in which the principal and the sagittal axis are +crossed) divides it into symmetrical equal halves and is perpendicular to +the frontal axis. + +Three different original elements of structure are recognisable in the +majority of NASSELLARIA, viz., (1) a vertical simple ring, the primary or +sagittal ring, placed vertically in the sagittal plane and enclosing the +median plane of the central capsule; (2) a basal tripod, composed of three +diverging radial rods, which are united on the basal pole of the central +capsule and are either expanded horizontally or descend; (3) an ovate or +subspherical, simple lattice-shell, the cephalis or capitulum, which +surrounds the central capsule and exhibits a peculiar structure on its +basal pole. + +These three important original elements of structure--the sagittal ring, +the basal tripod, and the latticed cephalis--are so united in the majority +of NASSELLARIA that the cephalis rests upon the tripod and includes the +sagittal ring wholly or partially. The simplest realisation of this typical +union is afforded by the Archiperida and Tripospyrida, and these may be +derived from the simpler important Stephanid _Cortina_ (Pl. 83, fig. 9; Pl. +92, fig. 21; Pl. 97, fig. 1). In this and in all other tripodal +NASSELLARIA, the three basal rods or the "cortinar feet" are constantly so +arranged that an odd or posterior rod, the "caudal foot" (_c_) is opposed +to the two anterior paired rods, the "pectoral feet" (one right, _p_", and +one left, _p_'). The caudal foot lies in the sagittal plane, and is +prolonged upwards into the dorsal rod of the sagittal ring (_b_), and over +this in a free ascending spine, the "apical horn" (_a_). The curved ventral +rod of the ring (_r_) is united above with the base of the apical horn, +below with the common centre of the tripod or the "cortinar centrum." The +characteristic position of the central capsule in this skeleton of +_Cortina_ is such that its basal pole (with the porochora) rests upon the +centre of the tripod, whilst its sagittal perimeter is separated from the +surrounding ring by the calymma; the numerous pseudopodia arising from its +base diverge downwards and are supported and protected by the three basal +feet of the tripod (Pl. 97, fig. 1). Compare also Pls. 51, 53, 84, 95, 98. + +The typical skeleton of _Cortina_, a tripodal ring, becomes more developed +in the Semantid _Cortiniscus_, in which the basal parts of the three +diverging feet are united {892}by a second horizontal ring, the cortinar or +basal ring (Pl. 92, figs. 11-13). The pores between the former and the +latter, or the "cortinar pores," may be regarded as the first beginning of +the lattice-plate, composing the "cephalis" or the simple primordial shell +in the Archiperida and Tripospyrida, and transmitted from these by heredity +to the great majority of NASSELLARIA. + +The "cephalis or capitulum" (the "Koepfchen" of the German authors) is +therefore the most important part of the skeleton in all #Cyrtellaria#, or +in all NASSELLARIA possessing a complete lattice-shell. In the +#Plectellaria#, however, or in those NASSELLARIA which do not possess a +complete fenestrated shell, the "cephalis" is either imperfect or totally +wanting. The cephalis surrounds the enclosed central capsule on all sides +in the form of an ovate or subspherical lattice-shell, and is separated +from it only by the jelly-like calymma. The sagittal ring is either +enclosed in the wall of the cephalis (whole or partially), separating its +two lateral halves, or it is enclosed in the cavity of the cephalis and +connected with its sagittal perimeter by short beams. The base of the +cephalis (with the cortinar plate) often rests immediately upon the centre +of the tripod; in the majority of NASSELLARIA, however, this near relation +is altered by reason of later changes and secondary modifications. + +The number of various forms, developed from these simple original +structural elements of the skeleton, is astonishing, and there are +described more than three hundred genera and nearly two thousand species of +this legion in the following pages. This large number may be easily +increased by subsequent observers. Since in all these MONOPYLEA the +characteristic structure of the central capsule is identical, and also the +structural elements of the siliceous skeleton are similar, it is very +probable that they may have arisen from a single common stock. But it is +very difficult (and at present impossible) to explain a natural +monophyletic system of this large legion. The greatest difficulty is +presented by the fact that the three structural elements mentioned above, +viz., the sagittal ring, the basal tripod, and the latticed cephalis, are +not constantly united, but each alone may also constitute the skeleton by +itself. In this respect the following seven cases are possible, and are +actually realised. + +A. The skeleton is composed of the sagittal ring only and of its spiny +appendages, without basal tripod and without latticed cephalis. This is the +case in the majority of #Stephoidea# (Stephanida, Semantida, Coronida, and +Tympanida). + +B. The skeleton is composed of a basal tripod only (_Plagiacantha_), or of +a tripod in the centre of which arises a vertical apical horn +(_Plagoniscus_), and often of an irregular framework, arising from the rods +of the tripod; but there is neither a trace of a sagittal ring nor a +complete latticed cephalis. This is the case in the remarkable suborder +#Plectoidea# (Plagonida and Plectanida). + +C. The skeleton is composed of a latticed cephalis only, a simple ovate or +subspherical fenestrated shell, which encloses the monopylean central +capsule; there is no {893}trace of a sagittal ring nor of a basal tripod. +This is the case in the remarkable family of Cyrtocalpida (Archicorida and +Archicapsida), in numerous #Botryodea# and in other #Cyrtellaria#. + +D. The skeleton is composed of a sagittal ring and a basal tripod, without +latticed cephalis. This is the case in a few, but very important forms of +#Stephoidea#: _Cortina_, _Stephanium_, _Cortiniscus_, _Stephaniscus_, +_Podocoronis_, and some allied genera. + +E. The skeleton is composed of a sagittal ring and a latticed cephalis, but +without basal tripod. This is the case in numerous #Cyrtellaria#, in the +Circospyrida (or Zygospyrida apoda: _Dictyospyris_, _Circospyris_) and some +other #Spyroidea#; and in a large number of #Botryodea# and Cyrtoidea +eradiata (a part of the Sethocyrtida, Theocyrtida, Lithocampida, and +others). + +F. The shell is composed of a basal tripod and a latticed cephalis, but +without any trace of the sagittal ring. This is the case in numerous +Cyrtoidea triradiata and multiradiata, and perhaps in the majority of the +following families--Tripocalpida, Tripocyrtida, Podocyrtida, and +Podocampida. + +G. The shell is composed of all three above-mentioned elements, of a +sagittal ring, a basal tripod, and a latticed cephalis. This is the case in +the great majority of #Spyroidea# (with a few exceptions only), and perhaps +also in the majority of #Cyrtoidea#. + +The survey of these seven groups, A to G, each of which is represented by +numerous living forms, shows clearly how difficult and complicated the +morphology and phylogeny of the numerous NASSELLARIA must be. For all +possible combinations of the three original structural elements are +realised abundantly, and in such complicated relations, and so intermingled +in the different orders and families, that it seems nearly hopeless to +answer the question of their true origin. The identity in the structure of +the central capsule, however, in all these MONOPYLEA, makes it probable +that they have all arisen originally from the skeletonless Nassellida +(_Cystidium_, _Nassella_), either in a monophyletic or in a polyphyletic +way. In this respect the following phylogenetical hypotheses are possible. + +1. Monophyletic hypothesis, deriving all NASSELLARIA from a simple sagittal +ring (_Archicircus_, _Lithocircus_, &c., Pl. 81). The groups A, D, E, and G +may be derived easily from such a ring, but the groups B, C, and F only by +means of the hypothesis that the original ring may be completely reduced +and finally lost. This hypothesis was stated by me in the years 1877 to +1879, when I had got the first general survey of the astonishing number of +new NASSELLARIA in the Challenger collection, and as I had found the +sagittal ring in the majority of them. This, my former hypothesis, is +mentioned by Richard Hertwig (1879, _loc. cit._, pp. 68, 126). It was +afterwards supported with particular energy by O. Buetschli (1882, +Zeitschr. fuer wiss. Zool., Bd. XXXVI.). + +2. Monophyletic hypothesis, deriving all NASSELLARIA from a basal tripod +(_Triplagia_, _Plagoniscus_, &c., Pl. 91). The groups B, D, F, and G, all +triradiate, may {894}be derived easily from such a tripod; but the groups +A, C, and E only by means of the hypothesis that the original tripod may be +completely reduced and finally lost. This hypothesis was employed in 1881 +in my Prodromus, since I had convinced myself that the "triradial +structure" is prevalent in the great majority of NASSELLARIA, and is +perhaps more important than the sagittal ring. + +3. Monophyletic hypothesis, deriving all NASSELLARIA from a latticed +cephalis, a simple ovate or subspherical fenestrated shell without ring and +tripod (_Cyrtocalpis_, _Archicapsa_, &_c._). The groups C, E, F, and G may +be derived easily from such a cephalis, but the groups A, B, and D only by +means of the hypothesis that the sagittal ring as well as the basal tripod +may remain as the last remnants of a reduced cephalis. This hypothesis was +given in 1862 in my Monograph, where I constructed the first pedigree of +Radiolaria (p. 234). I there derived all the Cyrtida from the #Sphaeroidea# +(_Cyrtidosphaera_), supposing that _Cyrtocalpis_ and some other Monocyrtida +may form a direct phylogenetical passage from the #Sphaeroidea# to the +#Cyrtoidea#. + +4. Polyphyletic hypothesis, deriving the different groups of NASSELLARIA +from different skeletonless Nassellida, by development of simple siliceous +skeletons in different ways. Among the numerous polyphyletic hypotheses +which are possible, one of the simplest would be the supposition that three +different fundamental forms of skeleton may have arisen independently one +from another: (1) a simple sagittal ring as original form of the +#Stephoidea# and #Spyroidea# (A); (2) a simple basal tripod as original +form of the #Plectoidea# (B); (3) a simple latticed cephalis as original +form of the #Botryodea# and #Cyrtoidea# (C). This triphyletic hypothesis is +supported by R. Hertwig (1879, _loc. cit._, p. 136); he assumes that the +original skeletonless Nassellida (_Cystidium_) have produced three +different branches, his "Acanthodesmida" (= #Stephoidea# and #Spyroidea#) +with a primary ring, his "Plagiacanthida" (= #Plectoidea#) with a primary +tripod, and his Cyrtida (= #Botryodea# and #Cyrtoidea#) with a primary +cephalis. This hypothesis seems rather probable on the first view; but it +meets with the greatest difficulties in view of the fact that these three +original elements of the skeleton are more or less evidently combined in +the great majority of NASSELLARIA. The greatest difficulty arises from the +fact that often among very similar and closely allied forms the first +exhibits all three elements (A, B, C) combined, whilst the second has a +combination of A and B, the third of B and C, the fourth of A and C; and +there are other forms, very similar to the former, in which one element +only is recognisable. Another difficulty arises from the fact that the +intimate structure of the cephalis in the majority of #Cyrtellaria# is not +perfectly known, and often exhibits structures which are difficult to +explain with regard to the three elements A, B, C. Under these +circumstances further researches on the numerous imperfectly known +NASSELLARIA are required, and chiefly accurate observations on their more +minute structure and on their important ontogeny. + +{895}We divide the immense legion of NASSELLARIA into two large orders, the +#Plectellaria# without complete lattice-shell, and the #Cyrtellaria# with a +complete lattice-shell or a "cephalis," including the central capsule; the +latter, of course, have arisen from the former. The #Plectellaria# comprise +three different suborders, the #Nassoidea# (without skeleton), the +#Plectoidea# (with a tripodal skeleton, without ring), and the #Stephoidea# +(with a primary sagittal ring, with or without tripod). The #Cyrtellaria# +again also comprise three different suborders, the #Spyroidea# (with +bilocular cephalis and a sagittal constriction), the #Botryodea# (with +multilocular and lobate cephalis, exhibiting two or more constrictions and +three or more lobes), and the #Cyrtoidea# (with simple, unilocular +cephalis, without constriction). + +_Synopsis of the Orders and Suborders of_ NASSELLARIA. + + I. Order {No skeleton, 1. #Nassoidea#. + PLECTELLARIA. { + Nassellaria without {Skeleton with a basal tripod, + complete lattice-shell. { without ring, 2. #Plectoidea#. + { + {Skeleton with a sagittal ring + { (usually without tripod), 3. #Stephoidea#. + + {Cephalis bilocular, with a + { sagittal constriction, 4. #Spyroidea#. + II. Order { + CYRTELLARIA. {Cephalis multilocular, with + Nassellaria with a { two or more constrictions + complete lattice-shell. { and lobes, 5. #Botryodea#. + { + {Cephalis simple, without + { constriction and lobes, 6. #Cyrtoidea#. + + +---- + + +Order V. PLECTELLARIA, Haeckel, 1883. + +_Definition._--NASSELLARIA without complete lattice-shell, usually with an +incomplete skeleton, formed of a ring, a tripod, or an irregular framework. + + + +Suborder I. NASSOIDEA, Haeckel. + +_Definition._--NASSELLARIA without skeleton. Single family Nassellida. + + + +{896}Family XLV. #NASSELLIDA#, Haeckel. + + _Cystidina_, Haeckel, 1883, Sitzungsb. Jena Ges. fuer Naturw., Februar + 16. + +_Definition._--NASSELLARIA without skeleton. The soft body composed of a +monopylean central capsule (with porochora and podoconus) and of a +surrounding jelly-veil or calymma. + +The family #Nassellida# comprises the simplest and most primitive forms of +NASSELLARIA, the only group which is entirely without a skeleton. The +central capsule is therefore perfectly free and naked, enveloped by the +calymma only, as in the #Colloidea# among the SPUMELLARIA, in the +Phaeodinida among the PHAEODARIA. Probably these naked and skeletonless +MONOPYLEA must be regarded as surviving remnants of the common ancestral +group of this legion; but the possibility is not excluded that the few +observed forms are either young NASSELLARIA which have not yet secreted a +skeleton, or older NASSELLARIA which have lost their original skeleton. + +We distinguish in this small family two genera only: _Cystidium_ with +hyaline, not foamy calymma, without extracapsular alveoles, and _Nassella_, +with a very voluminous foamy calymma, including numerous large alveoles; +the former corresponds to _Actissa_ and the latter to _Thalassicolla_ among +the #Colloidea# or the skeletonless SPUMELLARIA. But in these two latter +genera, as in all PERIPYLEA, the central capsule is perforated everywhere +by innumerable small pores; the two former genera, however, exhibit the +same characteristic podoconus in the central capsule, and the same +porochora at its base, as all the other MONOPYLEA. The pseudopodia are +protruded from the central capsule through the porochora only. + +_The Central Capsule_ is in the two observed genera either ovate or nearly +spherical, usually slightly tapering towards the basal mouth. Its +transverse section is constantly circular. The membrane of the capsule is +usually rather thick and double-contoured, and bears on the truncate basal +pole a circular "porochora" or area porosa, through which the pseudopodia +are protruded. The _porochora_ is either quite simple, circular, or in some +species trilobed, with three equal circular lobes, each of which is +surrounded by a girdle of small granules. The _podoconus_, or +"pseudopodial-cone," arising vertically from the horizontal basal +porochora, is half as long as the central capsule, or longer, simply +conical and finely striped longitudinally. The _nucleus_ lies usually in +the uppermost part of the central capsule, above or behind the podoconus, +and is either spherical or ovate, sometimes kidney-shaped. It includes one +or more nucleoli. + +_Synopsis of the Genera of Nassellida._ + + Calymma hyaline, without alveoles, 382. _Cystidium_. + + Calymma foamy, with numerous large alveoles, 383. _Nassella_. + + + +{897}Genus 382. _Cystidium_,[1] R. Hertwig, 1879, Organismus d. Radiol., p. +87. + +_Definition._--#Nassellida# with hyaline calymma, without extracapsular +alveoles. + +The genus _Cystidium_ is the simplest and most primitive among all +NASSELLARIA, and may be regarded as the common ancestral form of this +legion, for which it has the same high importance as _Actissa_ for the +SPUMELLARIA. The central capsule is quite simple, ovate or nearly +spherical, and included in a voluminous hyaline calymma, which contains no +large alveoles. _Cystidium_ differs from _Actissa_, its probable ancestral +form, in the possession of the "podoconus" and its basal "porochora," +characteristic of all NASSELLARIA or MONOPYLEA. + + +1. _Cystidium princeps,_ n. sp. (Pl. 91, fig. 1). + +Central capsule ovate, one and a third times as long as broad. Podoconus +with simple circular porochora, about half as long as the capsule, +surrounded at its base by red granules of pigment. Nucleus spherical. Three +equal oil-globules in the endoplasm. No pigment in the voluminous calymma, +which includes numerous xanthellae. + +_Dimensions._--Length of the central capsule 0.1, breadth 0.075; nucleus +0.035. + +_Habitat._--Indian Ocean, Maldive Islands (Haeckel), surface. + + +2. _Cystidium lecythium,_ n. sp. + +Central capsule ovate, one and a half times as long as broad. Podoconus +with simple circular porochora, three-fourths as long as the capsule. +Nucleus ellipsoidal. No oil-globules in the endoplasm. No pigment and no +xanthellae in the calymma. + +_Dimensions._--Length of the central capsule 0.12, breadth 0.08; nucleus +0.04. + +_Habitat._--Central Pacific, Station 271, surface. + + +3. _Cystidium inerme,_ R. Hertwig. + + _Cystidium inerme,_ R. Hertwig, 1879, Organismus d. Radiol., p. 87, Taf. + vii. figs. 1-1_b_. + +Central capsule subspherical, a little longer than broad. Podoconus about +two-thirds as long as the capsule, with trifid porochora, which is composed +of three equal circular lobes. Nucleus spherical. Numerous oil-globules in +the endoplasm. The calymma includes numerous xanthellae and brown pigment +around the mouth. + +_Dimensions._--Length of the central capsule 0.06, breadth 0.05; nucleus +0.03. + +_Habitat._--Mediterranean, Messina (R. Hertwig), surface. + + + +{898}Genus 383. _Nassella_,[2] nov. gen. + +_Definition._--#Nassellida# with foamy calymma, containing numerous large +extracapsular alveoles. + +The genus _Nassella_ differs from the preceding _Cystidium_, its probable +ancestral form, in the development of numerous large alveoles in the +extracapsular calymma, and therefore exhibits the same relation to it that +_Thalassicolla_ bears to _Actissa_ among the SPUMELLARIA. The foamy calymma +is very voluminous, and includes numerous symbiotic xanthellae. + + +1. _Nassella thalassicolla_, n. sp. + +Central capsule spherical. Podoconus with simple circular porochora, half +as long as the capsule. Nucleus spherical. Numerous oil-globules in the +endoplasm. Calymma spherical, without pigment, with numerous xanthellae and +large alveoles. + +_Dimensions._--Diameter of the central capsule 0.12, nucleus 0.04, calymma +0.6. + +_Habitat._--South Pacific, Station 300 (off Juan Fernandez), surface. + + +2. _Nassella nassiterna_, n. sp. + +Central capsule ovate. Podoconus two-thirds as long as the capsule, trifid, +with three equal circular lobes (as in _Cystidium inerme_). Nucleus ovate. +Three equal large oil-globules in the endoplasm, corresponding to the three +lobes of the porochora. Calymma ovate, in the upper half much more +voluminous than in the lower, including numerous large alveoli and +xanthellae, and around the mouth masses of black pigment. + +_Dimensions._--Diameter of the central capsule 0.1, nucleus 0.03, calymma +0.8. + +_Habitat._--Indian Ocean, Madagascar (Rabbe), surface. + + +---- + + +Suborder II. PLECTOIDEA, Haeckel. + + _Plectoidea_ vel _Plectida_, Haeckel, 1881, Prodromus, p. 423. + _Plagiacanthida_ (_sensu ampliori_), R. Hertwig, 1879, Organismus d. + Radiol., p. 72. + +_Definition._--NASSELLARIA with a rudimentary, originally tripodal +skeleton, composed of radial spines, arising from one common central point +or central rod; the spines are simple or branched, and the branches may +form by concrescence of their meeting ends a loose wickerwork, but never a +complete lattice-shell. Never a ring in the skeleton. + +{899}The suborder #Plectoidea#, hitherto known by few species only of +"Plagiacanthida," comprises a large number of interesting NASSELARIA, which +belong partly to the simplest and most primitive forms of this legion. It +may be divided into two different families, Plagonida and Plectanida. In +the first family, Plagonida, the monopylean central capsule is supported by +a simple or rudimentary skeleton, composed only of a variable number of +radial spines united in a common centre. In the second family, Plectanida, +the branches of these radial spines become united and form a loose +irregular framework with wide meshes, partly enclosing the central capsule, +but never a perfect lattice-shell. + +The #Plectoidea# differ from the following suborder, the #Stephoidea#, in +the absence of the ring, characteristic of the latter. Some slight traces, +however, indicate a near affinity between the ringless #Plectoidea# and the +ring-bearing #Stephoidea#. Both these suborders of #Plectellaria# differ +from the closely allied #Cyrtellaria# (#Spyroidea#, #Botryodea#, and +#Cyrtoidea#) in the absence of a complete lattice-shell. The morphological +relation and phylogenetic affinity between the former and the latter have +already been discussed in the preceding description of the legion +NASSELLARIA (compare pp. 891-894). + +The first known species of #Plectoidea# was observed in the North Atlantic +(on the Norwegian shore) in 1855 by my late friend Edouard Claparede, and +described and figured in his Etudes, &c. (1858), under the name +_Plagiacantha arachnoides_. He considered it as a new genus of +Acanthometrina. Another species, from the Mediterranean, was described in +the same year by Johannes Mueller as _Acanthodesmia dumetum_ (1858, _loc. +cit._, Taf. i. fig. 3). A third species, also Mediterranean, was figured by +me in 1865 under the name _Acanthodesmia polybrocha_. Finally, Richard +Hertwig, 1879, in his Organismus der Radiolarien, gave a very accurate +description of another Mediterranean form, _Plagiacantha abietina_ (_loc. +cit._, Taf. vii. fig. 6). He first recognised the true character of +MONOPYLEA in their monaxonian central capsule, and observed at the same +time the first NASSELLARIUM without skeleton, called by him _Cyrtidium +inerme_ (_loc. cit._, Taf. vii. fig. 1). To these four known species, +representing three different genera, the rich collection of the Challenger +has added so many new forms that we may distinguish here not less than +seventeen genera and sixty-one species. In my Prodromus (1881, p. 423) I +arranged these in two subfamilies, the Plagonida and Plectanida, +constituting together the family Plectida (identical with the +"Plagiacanthida" of Hertwig and Buetschli). But at present, regarding the +important relations of these Plectida to the other NASSELLARIA, it seems +more convenient to give to them the rank of an independent suborder of +Radiolaria, under the name #Plectoidea#. + +The peculiar structure of the central capsule of the #Plectoidea#, first +recognised by Richard Hertwig, allows no doubt of their being true +MONOPYLEA or NASSELLARIA; and also their siliceous, originally triradiate +skeleton indicates the nearest affinity to {900}the other families of this +legion. But a very difficult and as yet unsolved problem is the important +question, in what manner these different groups of NASSELARIA are +phylogenetically connected. Either the #Plectoidea#--as the simplest of +all--are the original common ancestral group of this whole legion (as I +assumed in my Prodromus, 1881), or they are derived from the #Stephoidea# +(by reduction of the sagittal ring), or they have originated independently +from them (if we suppose a polyphyletic origin of the MONOPYLEA. Compare +above, p. 893, &c.). In any case the typical "triradial structure" of the +#Plectoidea#, prevalent also in the other groups of this legion, is a very +important and interesting fact. + +The triradial skeleton of the #Plectoidea# exhibits in the two families of +Plagonida and Plectanida a complete homology of development, so that each +genus of the latter may be derived from a corresponding genus of the +former, simply arisen by concrescence or union of the branches of the +radial spines. Therefore the only difference between the two closely allied +families is, that the branches of the radial spines in the Plagonida remain +free, whilst in the Plectanida they produce a loose framework or wickerwork +by union of their meeting ends. We express this complete homology in the +nomenclature of the #Plectoidea#, in each genus of Plagonida retaining the +syllable "Plag-"; in each genus of Plectanida, correspondingly, the +syllable "Plect-." + +The number of radial spines composing the skeleton is originally three, and +in all not triradial genera is probably derived from three. For better +survey we may divide each family, according to the different number of +rays, into four different subfamilies: A, with three radial spines +(Triplagida and Triplectida); B, with four radial spines (Tetraplagida and +Tetraplectida); C, with six radial spines (Hexaplagida and Hexaplectida); +and D, with numerous (seven to nine or more) radial spines (Polyplagida and +Polyplectida). The last three subfamilies have arisen probably from the +first triradial subfamily, by a secondary increase in the number of rays. + +The important signification of the triradial structure, recurring in the +most different groups of NASSELLARIA, has been already pointed out +sufficiently by myself and by R. Hertwig. But the triradial #Plectoidea# +offer also another interesting relation of this characteristic structure, +some simple forms of this order appearing nearly identical with the +isolated triradial spicula of certain #Beloidea# (Thalassosphaerida and +Sphaerozoida). Even some more complex quadriradial and sexradial forms of +the latter reappear in exactly the same shape also in the former. This +identity may be perhaps an important indication of true affinity (compare +below). + +The simplest and probably the most original kind of triradial structure is +exhibited by the genera _Triplagia_ and _Triplecta_ (Pl. 91, figs. 2, 7). +Here three equal radial spines lie in one horizontal plane and are united +in a common central point at equal angles, so that three lines connecting +their distal ends form a regular equilateral triangle. Simple triradial +spicula of the same regular form are also found in many {901}#Beloidea# +(_Lampoxanthium_, _Sphaerozoum_, &c., Pls. 2 and 4). The central capsule +of these simplest #Plectoidea# (with vertical main axis) rests +perpendicularly on the horizontal triangle, formed by the triradial +skeleton; the porochora of the former (or the "area porosa") rests upon the +central point of the latter. + +Another kind of triradial structure characterises the genera _Plagiacantha_ +and _Plectophora_. The three radial spines united in the central point lie +here not in one plane, but diverge in different planes, so that they +correspond to the three lateral edges of a three-sided pyramid. Commonly +the three spines are of equal size, and also the angles between them equal, +so that the pyramid is regular, sometimes very flat, at other times more +elevated. Spicula of exactly the same form are also found in some +#Beloidea#. Probably the three divergent spines are homologous to the +three basal feet of numerous #Spyroidea# and #Cyrtoidea#. The central +capsule, according to Hertwig, is placed in the apical part of the pyramid, +the axes of both being identical, and the porochora resting in the apex +itself. This fact seems to contradict the above-mentioned affinity; but +since in _Triplecta_ and _Triplagia_ the three spines lie horizontally, +they may have changed this original position in different direction, in +_Plagiacantha_ and _Plectophora_ becoming divergent upwards, whereas in +_Plagoniscus_ and _Plectaniscus_ (as in the #Spyroidea# and #Cyrtoidea#) +directed downwards. + +The triradial structure, common to the Triplagida and Triplectida, is +replaced by the quadriradial structure in the Tetraplagida and +Tetraplectida. Probably the latter have been derived from the former by +development of a fourth spine, and then this latter would correspond to the +"apical horn" of the other NASSELLARIA. But possibly also both structures +have originated independently from one another. We may distinguish not less +than four different kinds of the quadriradial structure. In the first case +all four spines are equal, and diverge from a common central point at equal +angles in different directions, corresponding to the four axes of a regular +tetrahedron (_Tetraplagia_ and _Tetraplecta_, Pl. 91, figs. 3, 8). + +In the second case all four spines are also equal, but they are not united +in a common central point, but opposite in pairs on the two poles of a +common central rod (_Plagonidium_). Therefore the skeleton possesses here +the same form as in the "geminate-biradiate" spicula of many #Beloidea# +(_e.g._, _Thalassoxanthium bifurcum_ and _Sphaerozoum furcatum_). The +development of the short horizontal middle rod, connecting the two +divergent pairs of spines, is here probably effected by the porochora of +the central capsule resting upon it. + +Whilst in these two cases of quadriradial structure all four spines are +equal, in two other cases they become differentiated in a very remarkable +manner. One spine is vertically directed upwards, in shape and size +different from the three others, which are directed downwards; the former +corresponding probably to the "apical horn," the latter to the three "basal +feet," which are found in the great majority of the #Spyroidea# {902}and +#Cyrtoidea#. Therefore we encounter here for the first time that +characteristic "cortinar structure" which is complete in _Cortina_ and +_Cortiniscus_ (Pl. 92, figs. 11-13, 21), and which may be regarded as the +strongest argument for a close relationship, or even for a common +monophyletic origin of all NASSELLARIA. + +The four spines, which we regard therefore as "cortinar spines," exhibit a +twofold kind of central junction. In the simpler case they are united in a +common central point, on which rests the porochora of the central capsule +(_Plagoniscus_ and _Plectaniscus_, Pl. 91, figs. 4, 9). These forms are +nearer to _Cortina_, and may be derived immediately from _Tetraplagia_ and +_Tetraplecta_ by differentiation of the four equal spines. In the other +case the four cortinar spines are separated in pairs, diverging from the +two poles of a short horizontal common "central rod" (_Plagiocarpa_ and +_Periplecta_, Pl. 91, figs. 5, 10). These forms may be compared with the +spicula of some #Beloidea# and derived from _Plagonidium_; but their basal +central rod may be compared again with the basal part of the sagittal ring +of _Cortina_, and this comparison becomes very important in those forms +like _Plagiocarpa procortina_ (Pl. 91, fig. 5). Here the four spines +approach very nearly to those of _Cortina_; the two ventral spines (or +pectoral feet) on the anterior pole of of the middle rod are equal, but +very different from the two dorsal spines, arising from the posterior pole; +the lower odd spine of the latter corresponds to the "caudal foot," the +upper spine to the "apical horn" of _Cortina_ and of the #Cyrtellaria#. The +vertical plane, determined by these two dorsal spines, is the sagittal +plane, and two opposite curved branches which lie in this plane (an upper +arising from the basal part of the apical spine and a lower arising from +the anterior pole of the middle rod) may be regarded as ventral parts of an +incomplete sagittal ring. This interesting form and some other similar +Tetraplagida may be regarded either as beginning #Stephoidea# (_Cortina_, +with incomplete sagittal ring) or as retrograde #Stephoidea# (_Cortina_, +with partly reduced sagittal ring). In every case they seem to indicate the +near relationship between the #Stephoidea# and #Plectoidea#. + +Another argument for this close relationship may be found in the position +of the central capsule in the interesting genus _Plagiocarpa_ (Pl. 91, fig. +5). Its basal part (with the porochora) rests upon the common central rod, +its ventral face upon the ventral prolongation of the latter, its dorsal +face upon the apical horn; its axis lies in the sagittal plane. The three +basal spines (the odd caudal and the paired pectoral feet) diverge from its +basal pole downwards in the same manner as in the Cortina, the Zygospyrida +and the Monocyrtida. + +Less important than those quadriradial Tetraplagida and Tetraplectida, are +the sexradial #Plectoidea#, the Hexaplagida and Hexaplectida. These may be +derived immediately from the triradial #Plectoidea# by prolongation of the +three primary original spines (of _Plagiacantha_) over the common central +point. Here also two {903}different kinds of central junction are found. In +the simpler case all six radial spines arise from a common central point +(_Hexaplagia_ and _Hexaplecta_). In the other case the six radial spines +arise from the two poles of a short horizontal common central rod, opposed +in two groups, each of three spines (_Plagonium_ and _Plectanium_, Pl. 91, +figs. 6, 11). In this latter case the single corresponding spines of the +two opposite groups are usually parallel, and exhibit therefore exactly the +same characteristic "germinate-triradiate" form which is found in many +#Beloidea# (_e.g._, in the common _Sphaerozoum punctatum_ and the similar +_Lampoxanthium punctatum_). + +The fourth and last group of this suborder contains the multiradiate +#Plectoidea#, the Polyplagida and Polyplectida. Here the number of radial +spines, diverging from the common centre, exceeds six, and is commonly +seven to nine, at other times ten to twelve or more (_Polyplagia_ and +_Polyplecta_, Pl. 91, fig. 12). When these two genera are better known from +further accurate observations, they may probably be divided into several +different genera (as already proposed in my Prodromus, 1881), since not +only the number, but also the central junction and the arrangement of the +numerous radial spines in the few observed species seems to be very +different. In some seven-radiate species (_e.g._, _Polyplecta heptacantha_) +four larger spines seem to be true "cortinar spines," the three smaller +secondary productions of the former. In the nine-radiate species the nine +spines seem to be sometimes basal branches of three primary spines, at +other times six secondary intercalated between the three primary (like +_Enneaphormis_, Pl. 57, fig. 9). In those multiradial #Plectoidea#, in +which the number of spines amounts to ten or twelve or more, the laws of +disposition are not yet recognised. + +Comparing these different productions of the skeleton in the numerous +#Plectoidea#, we find expressed two remarkable and very different +affinities. On the one hand many #Plectoidea# exhibit exactly the same +peculiar forms, which are only found besides in the #Beloidea# (as many +species of _Triplagia_, _Plagiacantha_, _Tetraplagia_, _Plagonidium_, +_Hexaplagia_, and _Plagonium_). On the other hand many #Plectoidea# bear +the same characteristic composition of the skeleton (or the "cortinar +structure") which is found in the Cortinida among the #Stephoidea#, and in +numerous #Spyroidea# and #Cyrtoidea#, which all agree in the possession of +three divergent basal feet and a vertical apical horn. A most important +argument for the close affinity of all these "cortinar NASSELLARIA" seems +to be given by the fact that the sagittal ring, which in _Cortina_ is +combined with the quadriradial structure, exhibits in the #Cyrtellaria# the +most different stages of development; in one group it is complete, in the +second incomplete, and in the third it has completely disappeared. + +The form of the radial spines composing the skeleton is usually three-sided +prismatic, gradually tapering from the thicker central base towards the +distal apex; sometimes they are slender pyramidal. More rarely the spines +are cylindrical or slender conical. In the majority of species the spines +are straight, in the minority more or {904}less curved. In very few species +only are they quite simple, without branches. They are nearly always more +or less branched, in many larger species very richly ramified. The modes of +ramification are rather variable. In the majority of #Plectoidea# the +spines are rather regularly verticillate, bearing an increasing number of +verticils, each of which is composed of three divergent branches. These +arise from the three edges of the spine, and all the branches of one edge +are usually parallel, either perpendicular to the spine, or directed at an +acute angle towards its apex. When the verticils are numerous (five to ten +or more), their size commonly tapers gradually towards the apex. Pinnate +spines occur more rarely than verticillate ones; in this case the two +paired lateral edges only of the prismatic spine bear opposite or alternate +branches, whilst the odd middle edge bears no ramules. In some species the +spines are singly or doubly forked. In many species (mainly those with +cylindrical spines) the ramification of the spines is more or less +irregular. + +Whilst in all Plagonida the branches of the spine remain perfectly free, in +all Plectanida, again, the meeting ends of the branches become united and +grow together, and by this concrescence a loose network arises, like +wickerwork, which partly encloses the central capsule and the central parts +of the spines, on which it rests. The meshes of this loose wickerwork are +large, either quite irregular, of very different size and form, or more or +less regular, with a certain form and arrangement of the meshes, effected +by the peculiar kind of ramification. Commonly the siliceous threads of the +arachnoidal wickerwork are very thin, often extremely delicate, +representing "pseudopodia metamorphosed into silex." Sometimes the +wickerwork is spongy. Its surface is constantly rough and bristly, with +free ends of the spine-branches, never covered with a regular +lattice-plate, as in the #Cyrtellaria# (#Spyroidea#, #Botryodea#, and +#Cyrtoidea#). + +The entire form of the central wickerwork is in the minority of Plectanida +quite irregular and indefinite; in the majority, however, a certain more or +less regular entire form is recognisable, effected by a certain, more or +less regular origin and mode of the connection of the meeting branches. So +in some species of _Triplecta_ (Pl. 91, fig. 7) the network represents a +triangular plate, of _Plectophora_ and _Plectaniscus_ a three-sided +pyramid, of _Tetraplecta_ (Pl. 91, fig. 3) a tetrahedron, and in many other +species a polyhedron of more or less regular form. Some species of +Plectanida become very similar to certain species of #Stephoidea#, +#Spyroidea#, and #Cyrtoidea#; so _Plectaniscus_ and _Periplecta_ approach +to _Cortina_ and _Cortiniscus_, _Pteroscenium_ and _Clathrocorys_, &c. +(compare Pls. 92, 93, 53, 64, &c.). They may represent a true phylogenetic +connection between both groups. But in these cases also the distinction is +determined by the fact that the true #Plectoidea# never possess a complete +sagittal ring (like the #Stephoidea#) nor a regular lattice-shell (like the +#Spyroidea#, #Botryodea#, and #Cyrtoidea#). + +{905}_The Central Capsule_ of the #Plectoidea# constantly exhibits the +peculiar characters of the MONOPYLEA or NASSELLARIA. It is commonly ovate, +more rarely ellipsoidal or even spherical, sometimes conical or +lentelliptical. The lower or basal pole of its vertical main axis +constantly exhibits the characteristic "porochora" (or the area porosa) of +the MONOPYLEA, and upon this rests the peculiar "podoconus" (or the +pseudopodial-cone) of this legion. On this porochora the central capsule is +in immediate connection with the central point of the skeleton, or the +horizontal common central rod, from which the radial spines arise. The +endoplasm, or the protoplasm of the central capsule (besides the +podoconus), contains commonly one large alveole or several small vacuoles, +and often pigment-granules. The nucleus is large, spherical or ovate, and +exhibits the same character as in all the other MONOPYLEA; it encloses +usually a single nucleolus. + +The position of the central capsule and its topographical relation to the +skeleton offers in the different #Plectoidea# some important and as yet +unsolved problems, which can be answered only by fresh and accurate +observations on living specimens. In _Triplagia_ and _Triplecta_, where the +triangular skeleton lies in a horizontal plane, the vertical main axis of +the central capsule is perpendicular to the central point of that +supporting triangle. In _Plagiacantha_ and _Plectophora_, where the three +radial spines correspond to the edges of a flat pyramid, the capsule is +enclosed in the pyramidal space of the latter, its basal pole touching the +apex; therefore in the normal position of the body the three divergent rays +are directed upwards. In _Tetraplagia_ and _Tetraplecta_ probably the same +position is retained, and therefore the fourth free spine, here developed, +is probably directed vertically downwards. In _Plagoniscus_ and +_Plectaniscus_, however, and moreover, in the closely allied _Plagiocarpa_ +and the corresponding _Periplecta_ (Pl. 91, figs. 5, 10) the position of +the central capsule, relative to the skeleton, seems to be inverse, and to +agree with that of the #Stephoidea# (_Cortina_, _Cortiniscus_, &c.) and the +#Cyrtoidea# (_Pteroscenium_, _Clathrocorys_, &c.); the three divergent +spines are here directed downwards (as basal feet), whilst the opposite +fourth spine is vertically directed upwards (as an apical horn); the +capsule rests here upon the tripod, which lies below it, and is inclined +with its dorsal face to the apical spine. In the majority of the other +#Plectoidea# the position of the central capsule and its relation to the +skeleton are not yet sufficiently observed, and require further accurate +researches. Its position seems to be very different in the several genera. +The capsule is never perforated by parts of the skeleton; this latter is +constantly extra-capsular. + +The physiological value of the skeleton, with regard to the central +capsule, is different in the Plagonida and Plectanida; in the former it +supports, in the latter it encloses the capsule like a shell. In the +Nassellida, where no skeleton is developed, the central capsule is quite +free and naked, enveloped only by the calymma. + +{906}The calymma or the extracapsular jelly-veil in all #Plectoidea# is +voluminous, and encloses not only the central capsule completely, but also +the skeleton wholly or partially. Its form is of the greatest value for the +development and configuration of the skeleton. Sometimes the calymma is +alveolate and foamy, as in _Nassella_ and the common _Thalassicolla_. In +several other #Plectoidea# the calymma seems to include numerous small +vacuoles, sometimes also pigment-granules. Xanthellae are commonly +scattered in it in great numbers. The pseudopodia, arising in a large bunch +from the porochora of the capsule, and running along the branches of the +radial spines, seem to be always numerous, richly branched, and with a +strong tendency to form anastomoses. The peculiar form of their network is +often exactly preserved in the conformation of the skeleton, produced by +them. The peculiarities of this network require further accurate +observations, as does the whole organisation of the #Plectoidea#. + +_Synopsis of the Families of_ #Plectoidea#. + + I. Skeleton (originally tripodal) composed of radial + spines united in a common centre and supporting the + central capsule, without wicker-work, 1. PLAGONIDA. + + II. Skeleton (originally tripodal) wattled, with irregular + wicker-work, composed of the united branches of radial + spines and enveloping the central capsule, 2. PLECTANIDA. + + + +Family XLVI. #PLAGONIDA#, Haeckel. + + _Plagonida_, Haeckel, 1881, Prodromus, p. 423. + _Plagiacanthida_ (_sensu strictiori_), Richard Hertwig, 1879, Organismus + d. Radiol., p. 72. + +_Definition._--#Plectoidea# with a spiny skeleton, composed of radial +spines, which arise from a common central point or central rod, and support +the free central capsule. + +The family #Plagonida# comprises those NASSELLARIA in which the skeleton is +only composed of united radial spines, arising from a common centre, +without any connection of meeting branches of the spines; the rudimentary +skeleton exhibits therefore neither a loose wickerwork (as in the closely +allied Plectanida), nor a ring (as in the #Stephoidea#), nor a complete +lattice-shell (as in the #Cyrtellaria#, the #Spyroidea#, #Botryodea#, and +#Cyrtoidea#). The central capsule, which possesses all the characters of +the MONOPYLEA, is therefore free, not enclosed, and only on one side +supported or partly protected by the radial spines or their branches. + +Two species only of Plagonida have been hitherto known. The first form +described is the _Plagiacantha arachnoides_, discovered thirty years ago +(1855) by Claparede on the western shore of Norway. Another species of the +same genus, from the Mediterranean, was very accurately described by +Richard Hertwig in 1879 in his Organismus der {907}Radiolarien +(_Plagiacantha abietina_). Upon these two species the latter founded his +family Plagiacanthida, a term which was afterwards employed by Buetschli +and others, for the whole group of #Plectoidea#. Many new forms are +contained in the collection of the Challenger, so that we may describe here +nine genera and thirty-four species. + +The family Plagonida may be divided into four different subfamilies, +according to the numbers of the radial spines which compose the skeleton: +Triplagida with three, Tetraplagida with four, Hexaplagida with six, and +Polyplagida with numerous (seven to nine or more) radial spines. These are +united commonly in one common central point, upon which rests the basal +pole of the central capsule, with the porochora. More rarely (in the genera +_Plagonidium_, _Plagiocarpa_, and _Plagonium_) the spines arise in two +opposite groups (each with two or three spines) from the two poles of a +common central rod; in this case the basal pole of the central capsule with +the porochora rests upon the horizontal common rod, which corresponds +probably to the basal part of the sagittal ring of the #Stephoidea# and +#Cyrtellaria#. + +The different forms which the skeleton of the Plagonida assumes in the +different genera of this family, and the important relations which these +exhibit on the one hand to the spicula of the #Beloidea#, and on the other +hand to the shell of some #Stephoidea# (_Cortina_, _Cortiniscus_, &c.) and +#Cyrtoidea# (_Pteroscenium_, _Clathrocorys_, &c.), have been already +pointed out in the preceding description of the suborder #Plectoidea#. +There it is also demonstrated, that all these different forms may be +derived from the simplest triradial forms, _Triplagia_ and _Plagiacantha_ +(compare above, pp. 900-904). + +Whilst the genera of the Plagonida are characterised by the number of the +radial spines and the peculiar mode of junction in a common central point +or at the two poles of a common central rod, the different species of this +family may be defined by the peculiar form of the spines and their +branches. These morphological characters have also been already described +above. We repeat here only that the radial spines in the majority of +species are three-sided prismatic and verticillate, each verticil commonly +with three branches. The distal ends of these branches remain constantly +free, and are never united, as is always the case in the following family. + +_The Central Capsule_ of the Plagonida exhibits the general characters of +all MONOPYLEA (compare above, p. 890). It is commonly ovate or ellipsoidal, +with vertical main axis; on the lower pole of the latter is the porochora +(or the "area porosa," from which all pseudopodia radiate). This is in +immediate connection with the central point or central rod of the skeleton, +in which its radial spines are united. The topographical relation of the +supporting skeleton to the central capsule seems to exhibit in the +different genera of the Plagonida remarkable differences, as already +demonstrated above (p. 905). + +{908}_Synopsis of the Genera of Plagonida._ + + ------------------------------------------------------------------------- + I. Subfamily Triplagida. Three radial spines. + ------------------------------------------------------------------------- + Three spines lying in one horizontal plane, 384. _Triplagia_. + + Three spines corresponding to the edges of a flat + pyramid, 385. _Plagiacantha_. + ------------------------------------------------------------------------- + II. Subfamily Tetraplagida. Four radial spines. + ------------------------------------------------------------------------- + {All four spines equal, 386. _Tetraplagia_. + Four spines arising from { + one common central point. {One apical spine + { opposed to three + { basal spines, 387. _Plagoniscus_. + + {All four spines equal, 388. _Plagonidium_. + Four spines arising in two { + pairs from the poles of a {One apical spine + common central rod. { opposed to three + { basal spines, 389. _Plagiocarpa_. + ----------------------------------------------------------------- + III. Subfamily Hexaplagida. Six radial spines. + ----------------------------------------------------------------- + Six spines arising from one common central point, 390. _Hexaplagia_. + + Six spines arising in two opposite groups from the + poles of a common central rod, 391. _Plagonium_. + ----------------------------------------------------------------- + IV. Subfamily Polyplagida. Numerous radial spines. + ----------------------------------------------------------------- + Numerous (seven to nine or more) radial spines + arising from a common centre (either a central + point or a branched rod), 392. _Polyplagia_. + + + +Subfamily 1. TRIPLAGIDA, Haeckel, 1881, Prodromus, p. 423. + +_Definition._--#Plagonida# with three radial spines. + + + +Genus 384. _Triplagia_,[3] Haeckel, 1881, Prodromus, p. 423. + +_Definition._--#Plagonida# with three radial spines, arising from one +common central point and lying in one horizontal plane. + +The genus _Triplagia_ and the following closely allied _Plagiacantha_ may +be regarded as the simplest and most primitive forms of the #Plectoidea#, +perhaps as the common ancestral stock of this suborder. The skeleton is +composed of three simple or branched radial spines, arising from one common +central point. These three spines in _Triplagia_ lie in one and the same +plane, whilst in _Plagiacantha_ they lie in different planes. Therefore the +former exhibits the simplest type of the triradial structure, common to the +majority of NASSELLARIA. + + +{909}1. _Triplagia primordialis,_ n. sp. (Pl. 91, fig. 2). + +Spines straight, of equal size and similar form, equidistant, three-sided +prismatic, each with two pairs of opposite lateral branches, which are +correspondingly parallel to the two other spines; the proximal branches +twice as long as the distal branches. + +_Dimensions._--Length of each spine 0.2, of the basal branches 0.07. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +2. _Triplagia triradialis,_ n. sp. + +Spines straight, of equal size and similar form, equidistant, three-sided +prismatic, regularly pinnate, with six pairs of opposite pinnulae, tapering +gradually towards the distal ends; the basal pinnulae are again branched, +with straight ramules. + +_Dimensions._--Length of each spine 0.27, of the basal branches 0.08. + +_Habitat._--North Pacific, Station 256, surface. + + +3. _Triplagia horizontalis,_ n. sp. + +Spines curved, cylindrical, irregularly branched, with three primary and +nine to twelve secondary branches, which are also slightly curved. The +angles between the bases of the three spines are equal, but the size and +form of the branches different. + +_Dimensions._--Length of the three spines 0.15 to 0.25, of the basal +branches 0.05 to 0.08. + +_Habitat._--West Tropical Pacific, Station 226, depth 4475 fathoms. + + + +Genus 385. _Plagiacantha_,[4] Claparede, 1856, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, November 13. + +_Definition._--#Plagonida# with three radial spines, arising from one +common central point and corresponding to the edges of a three-sided +pyramid. + +The genus _Plagiacantha_ agrees with the preceding _Triplagia_ in the +simple structure of the triradial skeleton, composed of three diverging +radial spines, which are united in a common centre at the oral pole of the +central capsule. But whilst the three radial rods of _Triplagia_ lie in one +horizontal plane, here they lie in different planes and correspond to the +three edges of a flat pyramid. _Plagiacantha arachnoides_, described in +1856 by Claparede, was the earliest known form of all #Plectoidea#. + + +{910}1. _Plagiacantha arachnoides_, Claparede. + + _Plagiacantha arachnoides_, Claparede, 1856, Monatsber. d. k. preuss. + Akad. d. Wiss. Berlin, November 13. + + _Plagiacantha arachnoides_, Claparede, 1858, Etudes sur les Infusoires et + les Rhizopodes, p. 462 (pl. xxii. fig. 8). + + _Acanthometra arachnoides_, Claparede, 1855, Monatsber. d. k. preuss. + Akad. d. Wiss. Berlin, p. 675. + +Spines straight, cylindrical, divided into three divergent straight +branches of equal size; each branch two to three times as long as the +simple thicker basal part. + +_Dimensions._--Length of the spines 0.12 to 0.2 of the branches 0.08 to +0.14. + +_Habitat._--North Atlantic, coast of Norway, Claparede, surface. + + +2. _Plagiacantha furcata_, n. sp. + +Spines straight, cylindrical, divided into two divergent straight branches +of equal size, of about the same length as the simple basal part. The +spines and their branches are smooth. + +_Dimensions._--Length of the spines 0.24, of their fork-branches 0.12. + +_Habitat._--North Pacific, Station 254, surface. + + +3. _Plagiacantha dodecantha_, n. sp. + +Spines straight, three-sided prismatic, in the middle with one verticil +composed of three divergent straight branches of equal size, of about the +same length as the simple basal part. The edges of the spines and their +branches are thorny. + +_Dimensions._--Length of the spines 0.24, of the branches 0.1. + +_Habitat._--Central Pacific, Station 274, surface. + + +4. _Plagiacantha abietina_, Richard Hertwig. + + _Plagiacantha abietina_, Richard Hertwig, 1879, Organismus d. Radiol., p. + 72, Taf. vii. figs. 6-6_b_. + +Spines straight, three-sided prismatic, with three verticils of three +divergent straight lateral branches, decreasing in size towards the distal +end; the branches of the first verticil about twice as long as those of the +second, and four times as long as those of the third verticil. All nine +branches of each spine simple, straight, three-sided pyramidal. + +_Dimensions._--Length of the spines 0.2 to 0.3, of the basal branches 0.06 +to 0.08. + +_Habitat._--Mediterranean, Messina (R. Hertwig), surface. + + +5. _Plagiacantha verticillata_, n. sp. + +Spines curved, three-sided prismatic, with six to nine verticils of three +divergent branches, decreasing in size towards the distal end; the branches +of the first verticil about twice as long as those of the fourth verticil. +All branches simple, slightly curved, bristle-shaped. + +_Dimensions._--Length of the spines 0.27, of the basal branches 0.12. + +_Habitat._--South Pacific, Station 296, surface. + + +{911}6. _Plagiacantha elatine_, n. sp. + +Spines straight, three-sided prismatic, with prominent wing-like edges and +ten to twelve verticils of three divergent branches, decreasing in size +towards the distal end; the branches of the three or four basal verticils +are again ramified and much larger than the simple branches of the distal +verticils. + +_Dimensions._--Length of the spines 0.36, of the basal branches 0.14. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + + +Subfamily 2. TETRAPLAGIDA, Haeckel, 1881, Prodromus, p. 424. + +_Definition._--#Plagonida# with four radial spines. + + + +Genus 386. _Tetraplagia_,[5] Haeckel, 1881, Prodromus, p. 424. + +_Definition._--#Plagonida# with four equal radial spines, arising from one +common central point, and corresponding to the four axes of a tetrahedron. + +The genus _Tetraplagia_ is one of the most important #Plectoidea#, and +possibly the common ancestral form of many NASSELLARIA (compare above, p. +901). The skeleton is composed of four radial rods, diverging from one +common centre in different directions, and corresponding to the four axes, +which extend from the central point of a tetrahedron to the central points +of its four faces. The whole skeleton of _Tetraplagia_ exhibits therefore +the same form, which is observed in the single quadriradiate spicula of +some #Beloidea# (in some species of _Lampoxanthium_, _Sphaerozoum_, &c.). + + +1. _Tetraplagia geometrica_, n. sp. + +Spines straight, cylindrical, perfectly equal, corresponding in regular +disposition exactly to the four geometrical axes of a regular tetrahedron; +in the middle arise from each spine two opposite equal lateral branches of +half the length of the spine. + +_Dimensions._--Length of the spines 0.12, of the branches 0.06. + +_Habitat._--Central Pacific, Station 266, surface. + + +2. _Tetraplagia phaenaxonia_, n. sp. (Pl. 91, fig. 3). + +Spines straight or slightly curved, three-sided prismatic, with irregular +short branches arising from the three edges; the branches are thorny, +tapering towards the apex. + +_Dimensions._--Length of the spines 0.15, of the basal branches 0.03. + +_Habitat._--Tropical Atlantic, Station 332, surface. + + +{912}3. _Tetraplagia abietina_, Haeckel. + + _Plagiacantha abietina_, var. _quadrispina_, Richard Hertwig, 1879, + Organismus d. Radiol., p. 73. + +Spines straight, three-sided prismatic, verticillate, with six to eight +verticils of three simple straight branches; the branches of each edge are +parallel, tapering towards the distal end. R. Hertwig regards this species +only as a four-spined variety of his three-spined _Plagiacantha abietina_; +but a specimen, observed by me in Corfu, exhibited all the characters of +_Tetraplagia_. + +_Dimensions._--Length of the spines 0.2, of the basal branches 0.07. + +_Habitat._--Mediterranean (Messina, Corfu), surface. + + + +Genus 387. _Plagoniscus_,[6] n. gen. + +_Definition._--#Plagonida# with four unequal radial spines, arising from +one common central point; one vertical or apical spine opposed to three +divergent or basal spines. + +The genus _Plagoniscus_ agrees with the preceding _Tetraplagia_ (its +probable ancestral form) in the possession of four radial spines, diverging +from one common central point. But whilst in this latter all four spines +are equal, corresponding exactly to the four axes of a tetrahedron, here in +_Plagiocarpa_ an important difference exists between one vertical or apical +spine and three other divergent basal spines; these latter corresponding +probably to the three "feet," the former to the single "apical horn" of the +majority of NASSELLARIA. Perhaps we find here one of the oldest and +simplest types of their "triradial or cortinar structure" (compare above, +p. 902). + + +1. _Plagoniscus tripodiscus_, n. sp. (Pl. 91, fig. 4). + +Spines three-sided prismatic, thorny. Apical spine nearly straight, +verticillate, with four to five verticils of three thorny branches, +tapering towards the apex. Three basal spines somewhat shorter, curved, +with three thorny edges. + +_Dimensions._--Length of the apical spine 0.2, of the basal spines 0.15. + +_Habitat._--Central Pacific, Station 263, surface. + + +2. _Plagoniscus euscenium_, n. sp. + +Spines three-sided prismatic, thorny, with dentate edges, and three to six +verticils of three short branches. Apical spine straight, with six +verticils, nearly twice as long as the three curved basal spines, each of +which bears three verticils; the basal verticils larger and ramified. +Resembles somewhat Euscenium eucolpium, Pl. 53, fig. 12, but has no +latticed shell. + +_Dimensions._--Length of the apical spine 0.3, of the basal spines 0.16. + +_Habitat._--North Pacific, Station 247, surface, + + +{913}3. _Plagoniscus cortinaris_, n. sp. + +Spines three-sided prismatic, straight, verticillate. Apical spine with +twelve verticils, one and a half times as long as the three basal spines, +each of which bears eight verticils of three branches. The branches are +also prismatic, straight, on each edge parallel, tapering towards the apex, +in the three basal spines forked, in the apical spine more branched. +Similar to the cortinar skeleton of _Clathrocorys_ (Pl. 64, figs. 8-10). + +_Dimensions._--Length of the apical spine 0.24, of the basal spines 0.16. + +_Habitat._--South Atlantic, Station 338, surface. + + +4. _Plagoniscus nassellaris_, n. sp. + +Spines cylindrical, curved, irregularly branched. Apical spine half as long +as, and less branched than the three basal spines, which are sigmoidal, +nearly horizontally expanded in the proximal half, descending in the distal +half. + +_Dimensions._--Length of the apical spine 0.1, of the three basal spines +0.18. + +_Habitat._--West Tropical Pacific, Station 224, surface. + + + +Genus 388. _Plagonidium_,[7] Haeckel, 1881, Prodromus, p. 424. + +_Definition._--#Plagonida# with four equal radial spines, arising in pairs +from the two poles of a common central rod. + +The genus _Plagonidium_, and the following _Plagiocarpa_ possess four +radial spines, like the two preceding genera. But whilst the four rods in +these latter arise from a common centre, here they arise in two pairs from +the two poles of a common middle rod; they have therefore exactly the same +form which we find in the single spicula of some #Beloidea# (e.g., +_Thalassoxanthium furcatum_, _Sphaerozoum furcatum_, &c.). Probably the +middle rod is horizontal and serves as supporting base for the central +capsule, whilst two opposite spines are directed upwards, two other +downwards. + + +1. _Plagonidium bigeminum_, n. sp. + +Spines straight, three-sided prismatic, four to six times as long as the +common central rod, pinnate, with four to five pairs of opposite pinnulae, +the distal of which are simple, the proximal again branched. + +_Dimensions._--Length of the spines 0.16, of the middle rod 0.032. + +_Habitat._--Indian Ocean, Sunda Strait (Rabbe), surface. + + +{914}2. _Plagonidium quadrigeminum_, n. sp. + +Spines cylindrical, curved, eight to ten times as long as the common +central rod, in the distal half forked; the fork-branches curved, somewhat +longer than the basal part. + +_Dimensions._--Length of the spines 0.18, of the middle rod 0.02. + +_Habitat._--Antarctic Ocean, Kerguelen Island, Station 159, surface. + + + +Genus 389. _Plagiocarpa_,[8] Haeckel, 1881, Prodromus, p. 424. + +_Definition._--#Plagonida# with four unequal radial spines, arising in +pairs from the two poles of a common central rod; one ascending apical +spine opposed to three descending basal spines. + +The genus _Plagiocarpa_ agrees with the preceding _Plagonidium_ in the +possession of a common horizontal middle rod, the two poles of which bear +two pairs of divergent spines; but whilst in the preceding all four spines +are equal, here they are differentiated in the same manner as in +_Plagoniscus_, which differs only in the absence of the middle rod. The two +observed and closely allied species of this genus are of peculiar interest, +since they belong possibly to the common ancestral forms of the +NASSELLARIA; the basal middle rod corresponds perhaps to the basal part of +a sagittal ring, the apical spine to its dorsal part, the three other +spines to the basal feet (compare above, p. 902). + + +1. _Plagiocarpa procortina_, n. sp. (Pl. 91, fig. 5). + +Spines cylindrical, curved, thorny, three to four times as long as the +common middle rod. Apical spine and the meeting caudal spine (or the +posterior basal spine) somewhat longer and with more numerous thorns than +the two paired pectoral (or anterior) spines. From the common base of the +latter arises an anterior prolongation of the horizontal middle rod, which +in the sagittal plane is curved upwards and corresponds to the sternal foot +of many #Cyrtellaria#. An ascending branch of this spine is opposed to a +descending branch of the apical spine, both together forming an incomplete +sagittal ring. + +_Dimensions._--Length of the two larger spines 0.15, of the two smaller +0.12. + +_Habitat._--Mediterranean (Portofino near Genoa), surface. + + +2. _Plagiocarpa procyrtella_, n. sp. + +Spines of form and arrangement similar to those of the preceding species, +but longer and more branched, six to eight times as long as the shorter +common middle rod. The two characteristic {915}opposed branches (the +ascending branch of the basal rod and the descending branch of the apical +spine), which in the preceding species nearly compose a sagittal ring, are +here absent. + +_Dimensions._--Length of the two larger 0.27, of the two smaller 0.21. + +_Habitat._--North Atlantic, Iceland (Steenstrup), surface. + + + +Subfamily 3. HEXAPLAGIDA, Haeckel. + +_Definition._--#Plagonida# with six radial spines. + + + +Genus 390. _Hexaplagia_,[9] Haeckel, 1881, Prodromus, p. 424. + +_Definition._--#Plagonida# with six radial spines, arising from one common +central point. + +The genus _Hexaplagia_ differs from the preceding genera of Plagonida in +the possession of six radial spines, diverging from one common central +point. Commonly, these six spines seem to lie opposite in pairs in three +different meridian planes, and in this case _Hexaplagia_ may be regarded as +a _Plagiacantha_, the three radial spines of which are prolonged over the +basal pole of the central capsule. But in other species the six spines seem +to lie in different planes. Further observations are required. + + +1. _Hexaplagia arctica_, n. sp. + +Spines opposite in pairs in three diameters, crossed in the common centre, +straight, three-sided prismatic, with dentate edges. The three pairs are +equal, but the upper spine of each pair only half as long as the lower +spine. + +_Dimensions._--Length of the upper spine 0.13, of the lower 0.27. + +_Habitat._--Arctic Ocean (Greenland), in the stomach of a Medusa (Olrik). + + +2. _Hexaplagia antarctica_, n. sp. + +Spines opposite in pairs in three diameters, crossed in the common centre, +slightly curved, three-sided prismatic, with verticillate branches; the +three pairs are equal, but the lower spine of each pair bears three to four +verticils, each of three branches, and is two to three times as long as the +upper spine, which bears two verticils only. + +_Dimensions._--Length of the upper spine 0.12, of the lower 0.3. + +_Habitat._--Antarctic Ocean, Station 157, depth 1950 fathoms. + + +{916}3. _Hexaplagia collaris_, n. sp. + +Spines in opposite pairs in three diameters, crossed in the common centre, +straight, cylindrical, pinnate, with three to four pairs of opposite +lateral branches or regular pinnulae. All six spines are equidistant, of +equal size and similar form, and lie with their branches nearly in one +horizontal plane. Therefore they are similar to the six radial rods in the +collar septum of many #Spyroidea# and #Cyrtoidea# (_e.g._, _Calpophaena_, +Pl. 53, fig. 18). + +_Dimensions._--Length of all six spines 0.18, of their basal pinnulae 0.04. + +_Habitat._--East of New Zealand, Station 169, surface. + + +4. _Hexaplagia australis_, n. sp. + +Spines unequal, at unequal intervals, not opposite in pairs, cylindrical, +irregularly branched and curved. In this species a definite arrangement of +the six different spines could not be detected. + +_Dimensions._--Length of the spines 0.2 to 0.3, of their largest branches +0.1. + +_Habitat._--South of Australia, Station 160, surface. + + + +Genus 391. _Plagonium_,[10] Haeckel, 1881, Prodromus, p. 423. + +_Definition._--#Plagonida# with six radial spines, arising in two opposite +divergent groups from the two poles of a common central rod. + +The genus _Plagonium_ differs from the preceding closely allied +_Hexaplagia_ in the remarkable peculiarity, that the six radial spines do +not arise from one common central point, but from the two poles of a common +horizontal middle rod; three divergent spines on each pole. The skeleton of +_Plagonium_ exhibits therefore the same remarkable form which is found in +the isolated spicula of numerous #Beloidea# (_e.g._, _Lampoxanthium +punctatum_, _Sphaerozoum punctatum_), and bears the same relation to +_Hexaplagia_ that _Plagonidium_ does to _Tetraplagia_. + + +1. _Plagonium sphaerozoum_, n. sp. (Pl. 91, fig. 6). + +Spines straight and stout, three-sided prismatic, about twice as long as +the common middle rod, irregularly branched or nearly verticillate, with +short thorny branches. Similar to the single spicula of some species of +_Sphaerozoum_ and _Lampoxanthium_. + +_Dimensions._--Length of the spines 0.12, of the middle rod 0.06. + +_Habitat._--Equatorial Atlantic, Station 347, surface. + + +{917}2. _Plagonium lampoxanthium_, n. sp. + +Spines irregularly curved, slender, cylindrical, six to eight times as long +as the common middle rod, in the proximal half smooth, in the distal half +covered with short thorns. (Similar to an isolated spiculum of +_Lampoxanthium punctatum_ or of _Sphaerozoum variabile_, Pl. 4, fig. 5.) + +_Dimensions._--Length of the spines 0.18, of the middle rod 0.03. + +_Habitat._--North Pacific, Station 240, surface. + + +3. _Plagonium arborescens_, n. sp. + +Spines irregularly curved and branched, slender, cylindrical, thorny, +twelve to sixteen times as long as the middle rod; the branches are large, +arborescent, their ramules again ramified and very thorny. + +_Dimensions._--Length of the spines 0.2 to 0.25, of the middle rod 0.02. + +_Habitat._--Indian Ocean, Madagascar (Rabbe), surface. + + +4. _Plagonium trigeminum_, n. sp. + +Spines straight, slender, cylindrical, four to six times as long as the +middle rod, in the basal half smooth, in the distal half arborescent, with +three to four irregular verticils of ramified branches. (Similar to a +single spiculum of _Sphaerozoum verticillatum_, Pl. 4, fig. 7.) + +_Dimensions._--Length of the spines 0.15 to 0.2, of the middle rod 0.05. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +5. _Plagonium distriactis_, n. sp. + +Spines straight and stout, three-sided prismatic, smooth, ten to twelve +times as long as the middle rod; each on the distal end cleft into three +divergent straight branches, which are again trichotomous. + +_Dimensions._--Length of the spines 0.15 to 0.18, of the middle rod 0.015. + +_Habitat._--South Pacific, Station 288, surface. + + + +Subfamily 4. POLYPLAGIDA, Haeckel, 1881, Prodromus, p. 424. + +_Definition._--#Plagonida# with numerous (seven to nine or more) radial +spines. + + + +Genus 392. _Polyplagia_,[11] n. gen. + +_Definition._--#Plagonida# with numerous (seven to nine or more) radial +spines, arising from a common centre and lying in different planes. + +{918}The genus _Polyplagia_ alone represents the small subfamily of +Polyplagida, distinguished from the other Plagonida by the multiplication +of the radial spines, the number of which amounts to seven to nine or more. +This increased number is commonly the result of an intercalation of new +spines between the three or four primary spines; it is sometimes also +effected by stronger development of branches of the latter, which become +independent. The following five species of this genus are very different, +require further investigation, and perhaps represent different genera:-- + + +1. _Polyplagia septenaria_, n. sp. + +Seven radial spines, straight, three-sided prismatic, verticillate, of +different sizes; four larger spines correspond to the four axes of a +tetrahedron (running from the centre to the four corners), each with five +to six verticils of three simple slender branches; one of these four main +spines seems to be the apical, the three others the basal spines of +_Plagiocarpa_; in the three meridian planes between the latter and the +former lie the three smaller spines, diverging upwards, each with two to +three verticils. (Similar to _Polyplecta heptacantha_, Pl. 91, fig. 12, but +without connection between the branches.) + +_Dimensions._--Length of the four major spines 0.26, of the three minor +0.11. + +_Habitat._--Central Pacific, Station 274, surface. + + +2. _Polyplagia octonaria_, n. sp. + +Eight radial spines, straight, three-sided prismatic, of equal size, +arising in two opposite groups from the two poles of a short common middle +rod (as in _Sphaerozoum arborescens_, Pl. 4, fig. 8, and in other +#Beloidea#). The four spines of each group are divergent, six to eight +times as long as the middle rod, each spine armed with three to four +verticils of thorny branches. + +_Dimensions._--Length of the spines 0.15, of the middle rod 0.022. + +_Habitat._--Indian Ocean, Cocos Islands (Rabbe), surface. + + +3. _Polyplagia novenaria_, n. sp. + +Nine radial spines of equal size, straight, cylindrical, lying nearly in a +horizontal plane, or forming a very flat pyramid. Near the common central +point every three spines arise from a short common rod, so that the centre +of the skeleton is triradial. Each spine bears towards the apex two +divergent straight lateral branches. This species may have been derived +from _Plagiacantha arachnoides_ by shortening and reduction of the basal +parts of the three original branched primary spines. + +_Dimensions._--Length of the nine spines 0.24, of the three basal rods +0.02. + +_Habitat._--North Atlantic, Faeroee Channel (Gulf Stream), John Murray, +surface. + + +4. _Polyplagia duodenaria_, n. sp. + +Twelve radial spines of equal size, arising from a common central point, +and diverging in different directions. The twelve spines are very large, +opposite in six pairs, cylindrical, longitudinally {919}striped (the +expression of concentric lamellae), and with spinulate surface, covered +with innumerable small thorns. The basal quarter of each spine is straight +and simple, the second quarter twice forked, and these four fork-branches +are again in the outer half of the spine richly forked or ramified, with +diverging, slightly curved thin branches; each of the twelve spines with +about sixty to eighty terminal branches, the ends of which seem to fall +into a spherical face. The position of this remarkable species in this +family is doubtful. + +_Dimensions._--Length of the spines 0.12 to 0.16, of the simple basal part +0.04. + +_Habitat._--South Pacific (off Juan Fernandez), Station 299, surface. + + +5. _Polyplagia viminaria_, n. sp. + +Numerous (sixteen to twenty or more) radial spines of about equal size, +arising from a common central point and diverging in different directions, +richly and more or less irregularly branched. The ends of the numerous +small branches seem to fall into a spherical face. The large spines of this +species have the same form and structure as in the preceding, nearly allied +species, but are more numerous and more irregularly branched and disposed. + +_Dimensions._--Length of the spines 0.2 to 0.25, of the simple basal part +0.05. + +_Habitat._--North Pacific, Station 241, surface. + + + +Family XLVII. #Plectanida#, Haeckel. + + _Plectanida_, Haeckel, 1881, Prodromus, p. 424. + +_Definition._--#Plectoidea# with a wattled skeleton, composed of the +meeting and united branches of radial spines, which arise from a common +central point or central rod, and protect the partly enclosed central +capsule. + +The family #Plectanida# comprises those NASSELLARIA in which the skeleton +is composed of radial spines, arising from a common centre, and of a loose +wickerwork, produced by concrescence of the meeting branches of those +spines. This rudimentary wattled skeleton is either quite irregular or only +slightly regular, but it never assumes the form of a complete +lattice-shell, as in the #Cyrtellaria# (the #Spyroidea#, #Botryodea#, and +#Cyrtoidea#), nor does it exhibit a ring (as in the #Stephoidea#). The +central capsule is partly or wholly protected, and often entirely enclosed +by the wattled skeleton. + +Three species only of Plectanida have been hitherto known. The first +described form is _Plectophora arachnoides_, which its discoverer Claparede +observed in a living state in 1855 on the western coast of Norway, and +considered as a mere variety of his _Plagiacantha arachnoides_. Two other +species were afterwards observed in the Mediterranean, _Polyplecta +dumetum_, 1856, by Johannes Mueller (united by him with _Acanthodesmia_) +and _Polyplecta polybrocha_ by myself in 1864. Many new forms are found in +the {920}collection of the Challenger, so that we may here distinguish +eight genera and twenty-seven species. + +The family Plectanida may be divided into four different subfamilies, +according to the number of the radial spines which compose the skeleton. +Those four subfamilies, as also the genera contained in them, correspond +exactly to the four subfamilies of Plagonida, from which they have +originated: Triplectida with three, Tetraplectida with four, Hexaplectida +with six, and Polyplectida with numerous (seven to nine or more) radial +spines. These spines are usually united (as in the corresponding ancestral +Plagonida) in one common central point, upon which rests the basal pole of +the central capsule, with the porochora. More rarely (in the genera +_Periplecta_ and _Plectanium_) the spines arise in two opposite groups +(each of two or three spines) from the two poles of a common horizontal +central rod, which supports the overlying porochora of the central capsule. + +The different genera of Plectanida, which are enumerated in the following +synopsis, correspond so exactly to the different genera of Plagonida +described above, that probably each of the former has arisen from a +corresponding genus of the latter. The only difference between the two is, +that in all Plagonida the branches and ramules of the radial spines end +freely, without growing together, whilst in all Plectanida the meeting ends +of the neighbouring spines grow together and so produce a loose and +irregular wickerwork. Therefore the latter constantly possess meshes, which +are missing in the former. As soon as any form of Plagonida begins to +produce meshes by concrescence of meeting branches of the spines, it passes +over into a corresponding form of Plectanida. The loose wickerwork or +wattlework so produced is sometimes very irregular, at other times more or +less regular; but it never assumes the regular form of a complete +lattice-shell, as in the #Cyrtellaria# (#Spyroidea#, #Botryodea#, and +#Cyrtoidea#). The general differences which this wickerwork exhibits in the +different genera of Plectanida have been already described above (compare +pp. 900-904). + +_The Central Capsule_ of the Plectanida agrees perfectly with that of the +ancestral Plagonida, as well in general form and structure as in the +peculiar topographical relation to the radial spines (compare above, p. +905). A slight difference between the two families is effected by the +higher development of the skeleton in the Plectanida. Since the branches of +the radial spines in this family become united and form a loose wickerwork, +the central capsule becomes more or less enclosed by the latter, and more +perfectly protected, than in the Plagonida, where the branches remain free. +In this respect the Plectanida approach more nearly to the #Cyrtoidea# with +which they are connected by such transitional forms as _Plectaniscus_ and +_Periplecta_ on the one hand, _Cladoscenium_ and _Pteroscenium_ on the +other. + +{921}_Synopsis of the Genera of Plectanida._ + + ------------------------------------------------------------------------- + I. Subfamily Triplectida. Three radial spines. + ------------------------------------------------------------------------- + Three spines lying in one horizontal plane, 393. _Triplecta_. + + Three spines corresponding to the edges of a flat + pyramid, 394. _Plectophora_. + ------------------------------------------------------------------------- + II. Subfamily Tetraplectida Four radial spines. + ------------------------------------------------------------------------- + { All four spines equal, 395. _Tetraplecta_. + Four spines arising from { + one common central { One apical spine opposed + point. { to three basal spines, 396. _Plectaniscus_. + + Four spines arising in two pairs from the poles of + a common central rod; one apical spine different + common spines, 397. _Periplecta_. + ----------------------------------------------------------------- + III. Subfamily Hexaplectida. Six radial spines. + ----------------------------------------------------------------- + Six spines arising from one common central point, 398. _Hexaplecta_. + + Six spines arising in two opposite groups from the + poles of a common control rod, 399. _Plectanium_. + ----------------------------------------------------------------- + IV. Subfamily Polyplectida. Numerous radial spines. + ----------------------------------------------------------------- + Numerous (seven to nine or more) radial spines + arising from a common centre (either a central + point or a branched rod), 400. _Polyplecta_. + + + +Subfamily 1. TRIPLECTIDA, Haeckel, 1881, Prodromus, p. 424. + +_Definition_.--#Plectanida# with three radial spines. + + + +Genus 393. _Triplecta_,[12] Haeckel, 1881, Prodromus, p. 424. + +_Definition_.--#Plectanida# with three radial spines, arising from one +common central point and lying in one horizontal plane. + +The genus _Triplecta_ is the simplest and most primitive of the Plectanida, +and may therefore be regarded as the prototype of this family. The skeleton +represents a triangular lattice-plate with three radial beams. On the +central union of the latter rests the oral pole of the central capsule. +Since the axis of the latter is vertical, the lattice-plate must be +horizontal, serving for the expansion of the pseudopodia. _Triplecta_ has +arisen from _Triplagia_ by union of the branches of its three radial +spines. In the simplest case only three large meshes are formed, +corresponding probably to the three cortinar meshes in the collar septum of +many #Cyrtellaria#. + + +1. _Triplecta triangulum_, n. sp. + +Spines straight, equal, smooth, cylindrical, each in the basal half with +one pair of divergent straight lateral branches. The opposed branches of +every two neighbouring spines are united by a {922}thin convex bow. In this +way arises a very simple, equilateral triangular skeleton, with three equal +large meshes. + +_Dimensions._--Length of the spines 0.14, sides of the triangle 0.16. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms. + + +2. _Triplecta triactis_, n. sp. (Pl. 91, fig. 7). + +Spines straight, equal, three-sided prismatic, pinnate, each with three to +four pairs of opposite slender pinnulae or lateral branches; the pinnulae +of each spine are correspondingly parallel to the main rods of the other +two spines. All pinnulae branched and connected by a few slender bows, +marking the sides of a regular triangle. + +_Dimensions_.--Length of the spines 0.15, sides of the triangle 0.17. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + + +Genus 394. _Plectophora_,[13] Haeckel, 1881, Prodromus, p. 424. + +_Definition._--#Plectanida# with three radial spines, arising from one +common central point and corresponding to the edges of a three-sided +pyramid. + +The genus _Plectophora_ has been derived from _Plagiacantha_ by union of +the meeting neighbouring branches of the three radial spines, and exhibits +therefore to it the same relation that _Triplecta_ bears to _Triplagia_. +The loose framework so produced corresponds to the three sides of a flat +pyramid and supports the central capsule. + + +1. _Plectophora triomma_, n. sp. + +Spines equal, straight, three-sided prismatic, thorny, connected by three +convex bows, the meeting branches of lateral spines arising in one pair +from the middle part of each spine. Therefore the skeleton exhibits three +large ovate meshes only. + +_Dimensions._--Length of the spines 0.12, of the meshes 0.08. + +_Habitat._--North Pacific, Station 238, surface. + + +2. _Plectophora arachnoides_, Haeckel. + + _Plagiacantha arachnoides_, var., Claparede, 1858, Etudes sur les + Infusoires et les Rhizopodes, p. 462, Taf. xxii. fig. 9. + +Spines straight, cylindrical, trifid, with one pair of lateral branches. +The nine diverging, straight, and smooth branches are connected in the +distal part by slender concave bows, so that the whole skeleton exhibits +nine wide meshes, three larger pentagonal and six smaller triangular. + +_Dimensions._--Length of the spines 0.14, of their branches 0.07. + +_Habitat._--North Atlantic, west coast of Norway (Claparede), surface. + + +{923}3. _Plectophora novena_, n. sp. + +Spines slightly curved, three-sided prismatic, thorny, with two pairs of +lateral branches. The six smaller distal branches end freely, whilst the +six larger basal branches are connected by slender convex bows. There are +therefore nine wide meshes, as in the preceding closely allied species. + +_Dimensions._--Length of the spines 0.18, of the basal branches 0.08. + +_Habitat._--North Atlantic, Faeroee Channel (Gulf Stream) (John Murray), +surface. + + +4. _Plectophora pyramidalis_, n. sp. + +Spines straight, three-sided prismatic, with three to four verticils of +short lateral branches. The branches of the basal verticils are again +ramified, and form by connecting bows a delicate loose framework, covering +the three sides of a flat pyramid, the three edges of which are the three +radial spines. + +_Dimensions._--Length of the spines 0.2, base of the pyramid 0.16. + +_Habitat._--Central Pacific, Station 267, surface. + + + +Subfamily 2. TETRAPLECTIDA, Haeckel, 1881, Prodromus, p. 424. + +_Definition._--#Plectanida# with four radial spines. + + + +Genus 395. _Tetraplecta_,[14] Haeckel, 1881, Prodromus, p. 424. + +_Definition._--#Plectanida# with four equal radial spines, arising from one +common central point and corresponding to the four axes of a tetrahedron. + +The genus _Tetraplecta_ has been derived from _Tetraplagia_ by union of the +neighbouring branches of the four radial spines, diverging from a common +point in different directions. In some forms of this genus the four rods +seem to correspond exactly to the four axes, which are directed from the +centre of a tetrahedron towards its four corners; whilst in other forms the +four rods and the angles between them are perhaps not perfectly equal. + + +1. _Tetraplecta tetrahedra_, n. sp. + +Spines straight, equal, three-sided prismatic, pinnate, each with three or +four pairs of opposite straight slender pinnulae or lateral branches; the +pinnulae of each side are correspondingly parallel. {924}All pinnulae +connected by a few slender bridges, thus producing a delicate network with +irregular rhomboidal meshes. + +_Dimensions._--Length of the spines 0.15, of the basal branches 0.05. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +2. _Tetraplecta quadricornis_, n. sp. + +Spines in the basal half straight, in the distal half slightly curved and +irregularly branched, with two to three pairs of unequal alternate lateral +branches, the distal ends of which are connected by a few slender bows, +marking the six edges of an irregular tetrahedron. + +_Dimensions._--Length of the spines 0.22, of the basal branches 0.14. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +3. _Tetraplecta pinigera_, n. sp. (Pl. 91, fig. 8). + +Spines three-sided prismatic, straight, or in the basal half slightly +curved, verticillate; each spine with six to eight three-branched regular +verticils, tapering gradually towards the distal end. All branches of each +spine lie parallel in three equidistant meridian planes, and are connected +by delicate parallel threads, perpendicular to the branches. Therefore the +skeleton consists of four pine-shaped trees and twelve delicate triangular +wings with rectangular meshes. + +_Dimensions._--Length of the spines 0.25 to 0.3, of the basal branches 0.1 +to 0.15. + +_Habitat._--Central Pacific, Station 271, surface. + + + +Genus 396. _Plectaniscus_,[15] nov. gen. + +_Definition._--#Plectanida# with four unequal radial spines, arising from +one common central point; one vertical or apical spine opposed to three +divergent or basal spines. + +The genus _Plectaniscus_ has probably been derived from _Plagoniscus_ by +reticular union of the neighbouring branches of the four radial spines, and +exhibits therefore to it the same relation that _Tetraplecta_ bears to +_Tetraplagia_. Whilst in these two latter genera the four spines are equal, +in the two former genera there is an important difference between a +vertical spine (or apical horn) and three divergent (commonly larger) +spines, corresponding to the three basal feet of the triradiate +NASSELLARIA. Perhaps, therefore, _Plectaniscus_ is one of the remotest +ancestors of the latter; but differs in the absence of a complete +lattice-shell. + + +{925}1. _Plectaniscus cortiniscus_, n. sp. (Pl. 91, fig. 9). + +Spines straight, three-sided prismatic, with three to four verticils of +short perpendicular branches; the branches of the distal verticils are +simple and free, those of the proximal verticils again ramified and +connected by an arachnoidal network of delicate threads. The vertical +apical spine (or horn) is scarcely one-third or half as long as the three +divergent basal spines (or feet), and the angle between it and the latter +is smaller. + +_Dimensions._--Length of the apical spine 0.05 to 0.1, of the three basal +spines 0.18 to 0.2. + +_Habitat._--North Pacific, Station 244, surface. + + +2. _Plectaniscus tripodiscus_, n. sp. + +Spines curved, cylindrical, with a variable number of irregular branches, +which in the distal half of the spines are free, in the basal half again +ramified and connected by a loose spongy framework. The apical spine is +shorter and simpler, nearly straight, less ramified. + +_Dimensions._--Length of the apical spine 0.1, of the three basal spines +0.15 to 0.18. + +_Habitat._--North Pacific, Station 238, surface. + + +3. _Plectaniscus archiscenium_, n. sp. + +Spines slightly curved, three-sided prismatic, with two to three verticils +of short curved branches. The vertical apical spine is about twice as long +as the three basal spines, and connected with them by an irregular loose +framework. The three basal spines are connected together only by a simple +ring, so that between them remain three large collar holes, like those of +the similar and closely allied _Archiscenium quadrispinum_ (Pl. 53, fig. +11). + +_Dimensions._--Length of the apical spine 0.32, of the three basal spines +0.18. + +_Habitat._--South Pacific, Station 295, depth 1500 fathoms. + + +4. _Plectaniscus cladoscenium_, n. sp. + +Spines curved, three-sided prismatic. The three basal spines pinnate, with +four to five pairs of opposite curved pinnulae; the distal pairs are simple +and free, the basal pairs branched and connected by an irregular delicate +framework, which together with the apical spine forms a spongy cap-shaped +shell, similar to _Cladoscenium_. Apical spine about half as long, simple. + +_Dimensions_.--Length of the apical spine 0.1, of the three basal spines +0.18. + +_Habitat._--Central Pacific, Station 274, surface. + + +5. _Plectaniscus clathrocorys_, n. sp. + +Spines straight, three-sided prismatic, with seven or eight verticils of +ramified branches, which in the basal half are connected by an irregular +loose framework. In the distal half each of the three divergent basal +spines (or feet) is connected with the longer apical spine (or horn) by a +{926}fenestrated triangular lattice wing. Therefore the skeleton becomes +very similar to _Clathrocorys_ (Pl. 64, figs. 8-10), but wants the regular +central cephalis. + +_Dimensions._--Length of the apical spine 0.2, of the basal spines 0.14. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +Genus 397. _Periplecta_,[16] Haeckel, 1881, Prodromus, p. 424. + +_Definition._--#Plectanida# with four unequal radial spines, arising in +pairs from the two poles of a common central rod; one ascending apical +spine opposed to three descending basal spines. + +The genus _Periplecta_ has probably been derived from _Plagiocarpa_ (by +concrescence of the meeting spine branches), and has the same important +relation to a part of the triradial #Stephoidea# (_Cortina_, &c.) and +#Cyrtoidea# (_Pteroscenium_, &c.). It differs from the latter only in the +fact that the loose irregular framework connecting the bases of the four +cortinar spines is not a regular lattice-shell. + + +1. _Periplecta cortina_, n. sp. (Pl. 91, fig. 10). + +Spines of very different size and shape, three-sided prismatic. The apical +spine (or horn) is larger, nearly straight, and bears a verticil of three +large divergent branches, which are again ramified. The three basal spines +(or feet) are curved, pinnate, each with three to five pairs of opposite +simple curved branches. A small common central rod separates the two united +pectoral feet from the two other spines (the caudal foot and the apical +horn). The three basal feet are connected by three convex bows composing a +horizontal collar ring, and since the central rod is prolonged between the +pectoral feet to the ring, a very remarkable collar septum is formed with +four cortinar meshes. Above this septum an irregular spongy shell, +including the central capsule, is formed by a delicate framework, +interwoven between the apical horn and the three basal feet. + +_Dimensions._--Length of the apical spine 0.25 to 0.3, of the three basal +spines 0.15 to 0.2. + +_Habitat._--Central Pacific, Station 271, surface. + + +2. _Periplecta pteroscenium_, n. sp. + +Spines of very different size and shape, three-sided prismatic, +verticillate. The apical spine (or horn) with ten to twelve verticils, is +one and a half times as long as the three basal spines (or feet), which +bear six to eight verticils only; each verticil with three branches which +by communicating ramules form a loose irregular wickerwork. Similar to +_Pteroscenium pinnatum_, Pl. 53, figs. 14-16, but without a regular +lattice-shell. A short basal central rod separates two equal (pectoral) +spines from two unequal spines, the larger of the latter is the apical, the +shorter the caudal spine. + +_Dimensions._--Length of the apical spine 0.26, of the three basal spines +0.17. + +_Habitat._--Central Pacific, Station 274, surface. + + +{927}3. _Periplecta monocyrtis_, n. sp. + +Spines of nearly equal size and shape, cylindrical, irregularly branched. +The apical spine is straight, more branched and nearly twice as long as the +three basal spines. All four spines in the basal third connected by a loose +spongy framework, approaching the form of some Monocyrtida. + +_Dimensions._--Length of the apical spine 0.24, of the basal spines 0.13. + +_Habitat._--Central Pacific, Station 274, surface. + + + +Subfamily 3. HEXAPLECTICA, Haeckel. + +_Definition._--#Plectanida# with six radial spines. + + + +Genus 398. _Hexaplecta_,[17] Haeckel, 1881, Prodromus, p. 425. + +_Definition._--#Plectanida# with six radial spines, arising from one common +central point. + +The genus _Hexaplecta_ has probably been derived from _Hexaplagia_ by +concrescence of the meeting branches of the six spines, and therefore has +to it the same relation that _Plectophora_ bears to _Plagiacantha_. The two +species here described represent perhaps two different genera, since in the +first all six spines are equal, opposed in pairs, in the second different +in pairs (three upper smaller and three lower larger). + + +1. _Hexaplecta triaxonia_, n. sp. + +Spines equal, opposite in three crossed pairs, straight, three-sided +prismatic, thorny, in the distal half with three leaf-shaped, dentate +edges, in the basal half with three verticils of slender branches, which +are connected by parallel threads, and so form an arachnoidal network with +rectangular or rhomboidal meshes. + +_Dimensions._--Length of the spines 0.22, of their basal branches 0.06. + +_Habitat._--South Pacific, Station 285, depth 2375 fathoms. + + +2. _Hexaplecta tricladonia_, n. sp. + +Spines unequal, three larger spines (in the lower half of the body) being +opposite to three smaller spines (in the upper half). The latter are nearly +horizontally expanded, each bearing three straight divergent branches. The +larger are stronger, twice as long and armed with three verticils, each of +three branches. All six spines are slender, three-sided prismatic. Their +branches are very thin, thread-shaped, and form by their union a loose +network with irregular polygonal meshes. + +_Dimensions._--Length of the larger spines 0.25, of the smaller 0.12. + +_Habitat._--South Pacific, Station 291, surface. + + + +{928}Genus 399. _Plectanium_,[18] Haeckel, 1881, Prodromus, p. 424. + +_Definition._--#Plectanida# with six radial spines, arising in two opposite +divergent groups from the two poles of a common central rod. + +The genus _Plectanium_ has been derived from _Plagonium_ by concrescence of +the meeting branches, and bears therefore to it the same relation that the +preceding _Hexaplecta_ exhibits to _Hexaplagia_. Whilst in these two latter +genera the six spines arise from a common central point, they arise here in +two divergent groups from the two poles of a horizontal common middle rod, +similar to the spicula of many #Beloidea#. + + +1. _Plectanium trigeminum_, n. sp. (Pl. 91, fig. 11). + +Spines straight and stout, six to eight times as long as the common middle +rod, three-sided prismatic; in the distal half thickened, with three +divergent terminal thorns; in the basal half with three to four verticils +of thin lateral branches, which are again ramified, and by their united +threads produce an irregular loose framework. + +_Dimensions._--Length of the spines 0.25, basal breadth 0.005, terminal +breadth 0.02; length of the middle rod 0.03. + +_Habitat._--North Pacific, Station 244, surface. + + +2. _Plectanium ovodimare_, n. sp. + +Spines straight and stout, three-sided prismatic, about four times as long +as the common middle rod, gradually thinned towards the distal end; in the +basal half with two to three verticils of forked branches, which are +dichotomously ramified, and by their united threads form a loose ovate +framework. + +_Dimensions._--Length of the spines 0.17, of the middle rod 0.04. + +_Habitat._--North Pacific, Station 236, surface. + + +3. _Plectanium sphaerozoum_, n. sp. + +Spines straight, cylindrical, ten to twelve times as long as the common +middle rod, with six to eight verticils of thorny branches, tapering +towards the distal end; the branches of the verticils are simple in the +distal half, again ramified in the basal half, and here connected together +by irregularly branched threads forming a loose framework. (Resembles one +spiculum of _Sphaerozoum verticillatum_, Pl. 4, fig. 7, but is more richly +branched, with united ramules.) + +_Dimensions._--Length of the spines 0.2, of the middle rod 0.01. + +_Habitat._--Central Pacific, Station 266, surface. + + + +{929}Subfamily 4. POLYPLECTIDA, Haeckel, 1881, Prodromus, p. 424. + +_Definition._--#Plectanida# with numerous (seven to nine or more) radial +spines. + + + +Genus 400. _Polyplecta_,[19] Haeckel. + +_Definition._--#Plectanida# with numerous (seven to nine or more) radial +spines, arising from a common centre and lying in different planes. + +The genus _Polyplecta_ comprises provisionally all Plectanida possessing +seven or more radial spines, united in the centre of the framework. It may +be derived from _Polyplagia_ by meeting and concrescence of the free +branches. But as in the latter genus, here also the few observed species +are very different, perhaps of different origin, and may be afterwards +better separated as representatives of diverse genera. + + +1. _Polyplecta heptacantha_, n. sp. (Pl. 91, fig. 12). + + _Heptaplegma heptacantha_, Haeckel, 1882, MS. + +Seven unequal spines divergent from one common central point, slender, +slightly curved, three-sided prismatic. Four spines are much larger, twice +to three times as long and as thick as the three smaller spines. One of the +four larger spines is directed upwards (as "apical horn"), whilst the three +others diverge downwards (as "basal feet"). Each of the four larger spines +bears five to seven equidistant verticils of three divergent branches, the +proximal of which are branched, the distal simple. The three smaller spines +lie nearly horizontally, midway between the odd apical spine and the three +basal spines, and in the same meridian planes with them; each bears one +verticil of three divergent branches. All the branches are united by +arachnoidal threads, composing a loose wickerwork with irregular, generally +quadrangular meshes. + +_Dimensions._--Length of the four larger spines 0.27 to 0.33, of the four +smaller 0.1 to 0.14. + +_Habitat._--Central Pacific, Station 271, surface. + + +2. _Polyplecta enneacantha_, n. sp. + + _Enneaplegma enneacantha_, Haeckel, 1881, Prodromus, p. 425. + +Nine equal and equidistant, straight, cylindrical radial spines, lying +nearly in one plane, arise from an irregular spongy central framework; six +of them seem to be secondary, intercalated between three equidistant +primary spines, which are united in the centre. (This species resembles in +the nine-radial structure the remarkable _Enneaphormis rotula_, Pl. 57, +fig. 9, and may perhaps be derived from a similar species; but it has no +regular latticed shell.) + +_Dimensions._--Length of the spines 0.22, diameter of the framework 0.17. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +{930}3. _Polyplecta decacantha_, n. sp. + + _Pentaplegma decacantha_, Haeckel, Prodromus, p. 425. + +Ten radial spines, curved, cylindrical, irregularly branched, diverge in +different directions and seem to arise in pairs from an irregular central +framework, in the centre of which five primary spines are united; the +latter correspond probably to the five spines of _Pentaspyris_, &c. The +density of the spongy central framework did not allow of an accurate +investigation, and makes it doubtful whether this species is not a +_Spongiomma_. + +_Dimensions._--Length of the spines 0.3 to 0.4, diameter of the framework +0.18. + +_Habitat._--Tropical Atlantic, Station 338, depth 1990 fathoms. + + +4. _Polyplecta polybrocha_, Haeckel. + + ? _Acanthodesmia polybrocha_, Haeckel, 1865, Zeitschr. f. wiss. Zool., + Bd. xv. p. 368, Taf. xxvi. fig. 3. + + _Plegmosphaera polybrocha_, Haeckel, 1881, Prodromus, p. 455. + +Numerous (twenty to thirty or more) radial spines, thin, cylindrical, +curved and irregularly branched, arising from an irregular central spongy +framework, are connected by numerous slender arches. The specimen observed +by me in 1880 in Portofino was a true _Polyplecta_, with three primary +spines centrally united, between which numerous other spines were +intercalated. The similar specimen, however, observed in 1864 in +Villafranca, and figured, _loc. cit._, was perhaps a _Plegmosphaera_. + +_Dimensions._--Length of the radial spines 0.05 to 0.1, diameter of the +framework 0.16. + +_Habitat._--Mediterranean (Villafranca, Portofino), surface. + + +5. _Polyplecta dumetum_, Haeckel. + + _Acanthodesmia dumetum_, J. Mueller, 1868, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 30, Taf. i. Fig. 3. + +Numerous (ten to twelve or more) radial spines, thin and straight, with a +few straight lateral branches, diverge in different directions and are +connected by a few slender curved arches. Some similar forms, but more +developed, with numerous branches and curved rods, are found in the Pacific +Radiolarian ooze, and represent probably different species. + +_Dimensions._--Length of the radial spines 0.05 to 0.08, of the branches +0.02 to 0.03. + +_Habitat._--Mediterranean, French shore (Cette and Saint Tropez), Johannes +Mueller, surface. + + +{931}---- + + +Suborder III. STEPHOIDEA, Haeckel. + + _Stephoidea_ vel _Stephida_, Haeckel, 1881, Prodromus, p. 444. + _Acanthodesmida_ (_sensu ampliori_), Buetschli, 1882, Zeitschr. f. wiss. + Zool., vol. xxxvi. p. 495. + +_Definition._--NASSELLARIA without complete lattice-shell, with a skeleton +composed of one or more simple rings, which may be united by a loose +framework and are separated by large openings or gates. One primary or +sagittal ring, determining the sagittal or median plane of the bilateral +body, encloses the monaxonian central capsule. + +The suborder #Stephoidea#, hitherto known by a few species only of +"Acanthodesmida," comprises a large number of interesting NASSELLARIA (now +more than two hundred species), which possess peculiar interest for the +morphology and phylogeny of this legion. The monaxonian central capsule of +the #Stephoidea# is surrounded either by one simple ring or by a complex +system of several loosely connected rings; these may be united by a loose +framework of connected branches, but never produce a complete +lattice-shell, as is constantly the case in the #Spyroidea#, #Botryodea#, +and #Cyrtoidea#. Therefore there remain between the parts of the connected +rings a few large openings which we call "gates," separating them from the +numerous small "pores" of the complete lattice-shells. In the most simple +case, if only one ring be formed, there is also present only one "gate," +the aperture of this simple ring. + +The first known species of #Stephoidea# were observed in the Mediterranean +by Johannes Mueller in 1856, and described and figured in his last treatise +(1858) under the names _Lithocircus annularis_ (_loc. cit._, Taf. i. fig. +1) and _Acanthodesmia vinculata_ (_loc. cit._, Taf. i. figs. 4-7). In the +following year I myself observed two other living species in the +Mediterranean, and described them in my Monograph (1862, pp. 268, 270) as +_Zygostephanus muelleri_ (Taf. xii. fig. 2) and _Prismatium tripleurum_ +(Taf. iv. fig. 6). For these four longest known #Stephoidea# I founded the +new family of Acanthodesmida (_loc. cit._, p. 265), but united with them +two other similar genera which I afterwards separated:--_Plagiacantha_ +(belonging to the #Plectoidea#) and _Dictyocha_ (belonging to the +PHAEODARIA). + +When, in 1876, I received the rich material of the Challenger collection, I +was astonished to find in it an enormous number of new, similar, and partly +very interesting "Acanthodesmida," which were afterwards arranged in my +Prodromus (1881, p. 444) in thirty-eight different genera and four +"subfamilies," all united in one single large family, "Stephida or +Monopylaria cricoidea." I retain here this natural group in the same sense, +but give to it the rank of a "suborder," separating at the same time its +four subfamilies as substantial "families." Since the names of the +{932}latter, proposed in the Prodromus, were not quite suitable, I replace +them here by the following more convenient names:-- + + 1. Family Stephanida (= Monostephida, 1881, p. 447). Skeleton entirely + formed by one simple ring (the primary vertical sagittal ring). The only + "gate" is the simple aperture of the ring. + + 2. Family Semantida (= Dyostephida, 1881, p. 446). Skeleton composed of + two rings, perpendicular to one another; the primary vertical sagittal + ring bears at the base a horizontal basal ring; between the two rings two + or more "basal gates remain." + + 3. Family Coronida (= Triostephida, 1881, p. 445). Skeleton composed of + two crossed vertical or meridional rings, perpendicular to one + another--the primary sagittal ring and the secondary frontal ring. + Commonly the two vertical rings are united at the base by a horizontal + basal ring, and between them remain two or more "basal gates." + + 4. Family Tympanida (= Parastephida, 1881, p. 446). Skeleton composed of + two parallel horizontal rings, and upper mitral ring, and a lower basal + ring, both connected by vertical or divergent columellae, which are parts + of vertical rings (primary sagittal, and secondary frontal ring). + +The peculiar structure of the central capsule of the #Stephoidea#, and +their character as true MONOPYLEA, were first recognised by Richard +Hertwig, who in 1879, in his Organismus der Radiolarien, gave an excellent +detailed description of it (_loc. cit._, pp. 68-72, Taf. vii. figs. 4, 5). +He also pointed out the near affinity of these "Acanthodesmida" with the +#Spyroidea# or Zygocyrtida, uniting the latter with the former family. + +A fuller explanation of this affinity, and of the morphological and +phylogenetic importance of the "Acanthodesmida," as ancestral forms of the +#Spyroidea# and #Cyrtoidea#, was given in 1882 by Buetschli (Zeitschr. f. +wiss. Zool., vol. xxxvi. pp. 495-501). He described in detail some +important fossil forms of Acanthodesmida as different species of +"_Stephanolithis_," a name which Ehrenberg had employed for various +ring-like fragments of Radiolarian shells, sponges, and other fossil +bodies. The four fossil species which Buetschli described represent four +different genera of #Stephoidea#, viz., _Semantis_ (_spinescens_), +_Semantrum_ (_muelleri_), _Semantidium_ (_haeckelii_), and _Tristephanium_ +(_hertwigii_). On the phylogenetic conclusions, derived from these accurate +observations, compare above, p. 893, &c. The topographical signification of +the parts, employed by Buetschli, is contrary to mine; he calls my dorsal +side the "anterior," and my ventral side the "posterior." + +The geometrical fundamental form of the body in nearly all #Stephoidea# +(with few exceptions) is distinctly bilateral or "dipleuric," so that we +can easily distinguish the {933}three different dimensive axes: the +principal axis with different apical and basal poles, the sagittal axis +with different dorsal and ventral poles, and the lateral axis with +equivalent right and left poles. In only a few genera this bilateral +symmetry is not expressed, and a simpler, more regular fundamental form +appears. The latter may be either primary (in the monaxonian _Archicircus_ +and _Lithocircus_) or secondary, afterwards acquired (in the octahedral +_Trissocircus_ and _Trissocyclus_, the cubical _Lithocubus_, the prismatic +_Eutympanium_, and some other forms). + +The most important element of the skeleton, with which the formation +begins, in all #Stephoidea# is the simple primary or sagittal ring, lying +vertically in the sagittal or median plane of the body and surrounding the +monaxonian central capsule. This sagittal ring is the only essential +element of the skeleton in all Stephanida, and is completely preserved in +all Semantida, also in the greater part of the Coronida and Tympanida. It +is partially reduced in the small groups of the true Acanthodesmida +(subfamily of Coronida) and the Dystympanida and Eutympanida (subfamilies +of Tympanida). Here only the vertical parts of it are preserved (dorsal and +ventral rod), whilst the horizontal parts are lost (mitral and basal rod). + +The sagittal ring lies constantly in the vertical median plane of the body, +and therefore divides the enclosed central capsule into a right and a left +half. It is rarely regular or subregular, commonly dipleuric or distinctly +bilateral, so that we may easily distinguish its dorsal and ventral, apical +and basal parts. The most important of these four parts or "rods" is the +"basal rod" or the inferior part, because here the ring is in closer +connection with the central capsule and its "porous area"; here peculiar +spines or branches are commonly developed, which even on the isolated ring +immediately determine the basal pole. The opposite upper part, or the +"mitral rod," is also often distinguished by the peculiar appendages. The +posterior part, or the "dorsal rod" (the anterior rod, _a_, in the +description of Buetschli), is commonly more straight, often quite vertical. +The opposite anterior part, or the "ventral rod" (the posterior rod, _b_, +of Buetschli), is usually more convex, and often strongly curved or +semicircular. + +Whilst this dipleuric or bilateral (commonly obliquely ovate or nearly +triangular) form of the sagittal ring is distinctly preserved in by far the +greater number of #Stephoidea#, it is replaced in some few genera by a more +regular, amphithect, diphragmatic, or biradial form. In this case we may +often suppose a primary regularity to exist, the dorsal and ventral parts +being not yet differentiated, as in _Archicircus_ and _Lithocircus_, +_Zygostephanus_ and _Protympanium_, and perhaps also in some other forms. +But in other cases the regularity is, on the contrary, secondary, being +derived from original bilateral forms. + +The rod of the sagittal ring is either cylindrical (with circular +transverse section) or angular (commonly with triangular transverse +section). In nearly all #Stephoidea# (with very few exceptions) branches or +apophyses are developed from the ring, regularly disposed and often of +great morphological importance. Commonly these {934}apophyses are developed +in pairs, growing symmetrically on both sides of the ring. The most +important of these apophyses are:--(1) Basal apophyses, arising from the +basal hole of the ring; (2) mitral apophyses, arising from the apical pole; +(3) dorsal apophyses, arising from the middle of the dorsal rod; and (4) +ventral apophyses, arising from the middle of the ventral rod. The two +former arise in the principal axis, the two latter in the sagittal axis of +the body. Very frequently the latter pair is replaced by two pairs of +transverse branches, one inferior (mandibular) and one superior (orbital). +The apophyses of the ring are either simple or branched, often very large, +richly ramified, and give origin to a number of further products. + +Whilst in the Stephanida the primary sagittal ring alone represents the +whole skeleton, it produces in all other #Stephoidea# one or more secondary +rings. The most important of these is the horizontal basal ring, appearing +first in the Semantida (Pl. 92). From the base of the sagittal ring there +arise in the horizontal basal plane two pairs of lateral branches or "basal +apophyses." The curved opposite branches of the corresponding pairs become +united on each side of the primary ring (right and left), and so produce a +second, horizontal ring, perpendicular to the former. This basal ring +encloses two paired basal gates, which are enclosed on the medial side by +the basal rod of the sagittal ring, and on the lateral side by two united +apophyses (_Semantis_, Pl. 92, figs. 1, 2). These two primary basal gates +are of the greatest morphological importance; we call them the "jugular +gates or jugular pores" (in the description of Buetschli, the pores I, +_loc. cit._, p. 498). The dorsal pair of basal apophyses (on their +posterior edge) are the coracal rods, _e_ (rods _e_ of Buetschli); the +opposite ventral pair (on their anterior edge) are the clavicular or +furcular rods, _f_ (rods _e_1 of Buetschli); compare Pls. 92-95, and their +explanation. + +The skeleton of _Semantis_, the prototype of the Semantida, thus assumes +the characteristic form of a signet-ring. The basal ring enclosing the two +jugular pores corresponds to the seal-plate. It is commonly more or less +horizontal; but often the apophyses descend obliquely (Pl. 92, figs. 1, 2, +13, &c.), more rarely laterally (Pl. 29, fig. 11). The further development +of this typical form is essentially effected by the production of new basal +pores in the horizontal seal-plate. In _Semantrum_ (Pl. 92, figs. 3, 4, 5) +we find already four basal gates. Behind the jugular gates is formed a +second pair, the "cardinal gates" (pores II of Buetschli). These are +enclosed on the anterior margin by the coracal rods (_e_), on the posterior +margin by the scapular rods (_d_), a third pair of basal apophyses, arising +behind the former from the sagittal ring and uniting with them (the rods +_e_2 of Buetschli). Commonly the two posterior, or cardinal gates are much +larger than the two anterior, jugular gates. This characteristic basal +plate of _Semantrum_, with two pairs of basal pores, is of the greatest +morphological importance, as it is inherited in by far the greater number +of the NASSELLARIA, though not so generally as Buetschli supposes. The +basal ring of _Semantrum_ is either more circular {935}or elliptical, or +more polygonal, and is connected with the basal rod of the sagittal ring by +three pairs of radial apophyses, the anterior furcular, the middle coracal, +and the posterior scapular rods. + +A third important form of Semantida is _Semantidium_ (Pl. 92, figs. 6, 7). +Here we find three pairs of basal pores in the seal-plate; the third pair, +newly formed, consists of the cervical gates (_e_), bounded in front by the +scapular rods (_d_), behind by a fourth pair of basal apophyses, the +cervical rods. + +The basal apophyses of the sagittal ring are not only of great +morphological importance, because they produce by their union three typical +pairs of basal gates or "collar pores," but also because their +prolongations often appear as typical basal feet. The distal prolongations +of the coracal rods appear in _Semantiscus_ (Pl. 92, figs. 16-18) as two +pectoral feet, those of the scapular rods as two tergal feet, whilst the +opposite prolongations of the basal rod of the sagittal ring appear as two +"sagittal feet" (in front an anterior or sternal, and behind a posterior or +caudal foot). In the typical _Cortiniscus_ (Pl. 92, figs. 11-13) only three +feet are developed; an odd caudal and two paired pectoral feet (compare +above, p. 891). The typical basal ring of the Semantida, with its paired +basal gates (_Semantis_), reappears in the majority of the Coronida, +differing from the former in the development of a second vertical ring, +which lies in the frontal plane (perpendicular to the sagittal ring), and +which we therefore call the frontal ring. In only one small group of the +Coronida the basal ring is absent, namely, in the Zygostephanida, and here +the frontal ring appears in the simplest form, as a complete elliptical +meridian ring, crossing the sagittal ring perpendicularly on the two poles +of the main axis (_Zygostephanus_, Pl. 93, figs. 1-4), Four large lateral +gates between the two rings remain open. This form may be derived directly +from the Stephanida in the following way; from both poles of a simple +sagittal ring there arise two opposite lateral apophyses, which in the +frontal plane become curved one towards the other, and united in the poles +of the transverse axis. The basal apophyses would be the coracal rods. But +it is also possible that _Zygostephanus_ was derived from _Semantis_ by the +loss of the furcular rods. + +The three typical rings (or the "dimensive rings") of the #Stephoidea# +appear in their most complete form in the subfamily Trissocyclida (Pl. 93, +figs. 7, 13). Here all three rings are undivided and completely developed +in the three dimensive planes, perpendicular one to another. Between them +there remain eight large open gates; the four superior are the four +"lateral gates" of _Zygostephanus_, the four inferior are the four basal +gates of _Semantrum_. The four latter are originally much smaller than the +four former; but in _Trissocircus_ and _Trissocyclus_ (Pl. 93, figs. 10-12) +they reach the same size. Therefore all eight gates are here of equal form +and similar size, and the basal ring, now a true equatorial ring, divides +the two meridional rings into two equal halves. + +In the Eucoronida, a third subfamily of Coronida, the sagittal and the +basal rings {936}are complete, but the frontal ring is incomplete, its +basal part being wanting (Pl. 82, figs. 4-6). Therefore we find here six +large gates between the three rings; four upper lateral gates (between the +two crossed vertical rings) and two lower basal gates (between the basal +rod of the sagittal ring and the two halves of the basal ring). +_Eucoronis_, the type of this subfamily, may be derived either directly +from _Semantis_ by development of a frontal ring, or from _Tristephanium_ +by loss of the basal part of the frontal ring. + +A quite simple basal ring with a single gate, distinguishes the fourth +subfamily of Coronida, the Acanthodesmida (_sensu restricto_), the genera +_Coronidium_ (Pl. 82, figs. 1, 2, 7, 8) and _Acanthodesmia_ (Pl. 93, fig. +5). The horizontal basal ring alone is here complete, whilst both vertical +rings (the sagittal and frontal rings) are incomplete, their basal parts +being wanting. Therefore there are here five gates, four lateral and one +basal. These forms may be derived from _Eucoronis_ by loss of the basal rod +of the primary sagittal ring. + +The Tympanida, the fourth family of #Stephoidea#, exhibit another type of +ring structure. Here two parallel horizontal rings are constantly +developed, one on the apical pole, the other on the basal pole of the +sagittal ring. The latter is the same basal ring as in the Semantida and +Coronida. The former is a "mitral ring," developed in the same manner, by +union of two pairs of horizontal lateral branches, which arise on both +sides from the apical rod (or mitral rod) of the sagittal ring. In the +simplest case these two parallel horizontal rings are connected only by the +sagittal ring, which is either complete (_Protympanium_, Pl. 93, fig. 14) +or incomplete (_Parastephanus_, Pl. 93, fig. 21). But commonly also an +incomplete frontal ring is present, so that the two horizontal rings are +connected by four vertical or subvertical rods; two of these "columellae" +are the dorsal and ventral rods of the sagittal ring, the two others are +the lateral rods of the frontal ring. Between the former and the latter are +sometimes developed two, four, or more accessory columellae (probably +halves of accessory incomplete diagonal meridian rings). In this way arise +the characteristic "drum-forms" of many Tympanida, in which the two +parallel horizontal rings correspond to the upper and lower rings of a +drum, whilst the connecting vertical columellae correspond to its parallel +lateral rods (Pl. 83, figs. 1, 2, &c.). + +Originally the two horizontal rings of these "drum-shells" are both +bisected by the complete sagittal ring, each provided with two lateral +gates (Protympanida). But in the Eutympanida both rings exhibit one simple +gate only, the apical and the basal rod of the sagittal ring being lost. In +the Paratympanida both rings are closed by a secondary lattice-plate whilst +in the Dystympanida the upper (mitral) ring alone is closed by such a +plate, the lower (basal) ring is open. In some Eutympanida the shell +assumes the strange form of a regular geometrical cube, the twelve edges of +which are represented by thin rods of silex (_Lithocubus_)--its four upper +edges represent the mitral ring, the four lower the basal ring; two +opposite of the four vertical {937}cube-edges are the lateral halves of the +frontal ring, the two other alternate ones are the remaining halves of the +reduced sagittal ring (dorsal and ventral rod) (Pl. 82, fig. 12). + +In many Tympanida and Coronida a loose irregular lattice or framework is +developed, which partly closes the large open gates. But this never reaches +the completeness of a true lattice-shell, such as we find in the +#Spyroidea#, #Botryodea#, and #Cyrtoidea#. In by far the greater number of +#Stephoidea# the corners, and partly also the rods, of the shell are armed +with numerous irregular spines, often forked or richly branched. Among +these spines the descending "basal apophyses" possess a peculiar +importance, since by their regular number and disposition they correspond +to the radial rods of the #Plectoidea#, and to the typical "feet" of the +#Spyroidea# and #Cyrtoidea#. The most important of them are the three +cortinar feet (one caudal and two pectoral) of _Cortina_, _Cortiniscus_, +&c. (compare above, p. 891). + +_The Central Capsule_ exhibits in the #Stephoidea# the same characteristic +structure as in all other MONOPYLEA, first exactly pointed out by Richard +Hertwig in 1879 (Organismus der Radiol., p. 71, Taf. vii. figs. 4, 5). Its +form is commonly ovate or ellipsoidal, sometimes also lentelliptical or +nearly spherical. It exhibits constantly on the basal pole the porochora or +porous area, and in the basal half the podoconus or pseudopodial cone. From +the surrounding sagittal ring it is separated by a thick jelly-like +calymma, which commonly exhibits numerous zooxanthellae. The numerous +pseudopodia are commonly branched, with rather rare anastomoses. The +membrane of the central capsule is thick. + +_Synopsis of the Families of_ #Stephoidea#. + + I. Skeleton composed of the simple vertical sagittal ring + only, without secondary rings, 1. STEPHANIDA. + + II. Skeleton composed of two crossed rings, a vertical + sagittal and a horizontal basal ring, 2. SEMANTIDA. + + III. Skeleton composed of two crossed vertical meridional + rings (a primary sagittal and a secondary frontal ring), + commonly also with a horizontal basal ring, 3. CORONIDA. + + IV. Skeleton composed of two parallel horizontal rings + (upper mitral and lower basal ring), both connected by + a vertical sagittal ring (and often by a vertical + frontal ring), 4. TYMPANIDA. + + + +Family XLVIII. #STEPHANIDA#, Haeckel (Pl. 81). + + _Monostephida_, Haeckel, 1881, Prodromus, p. 447. + +_Definition_.--#Stephoidea# with a simple sagittal ring, without any +lattice-work. + +The family #Stephanida# is the most simple of all #Stephoidea#, and +probably the common ancestral group of this suborder (compare above, p. +933). The skeleton {938}consists of a simple ring only, surrounding the +central capsule, and armed commonly with simple thorns or with larger +branched spines. The branches of these spines are constantly free, never +joining together. Therefore the shell exhibits no trace of fenestration or +lattice-work, no pores or gates, except the simple large gate of the ring +itself. In all other #Stephoidea# we find secondary gates or lattice-work. + +The first known form of this family is _Lithocircus annularis_, described +by Johannes Mueller in 1858 (Abhandl. d. k. Akad. d. Wiss. Berlin, p. 29, +Taf. i. fig. 1). He observed already the central capsule ("Blase") +surrounded by the circular ring of silex, and the calymma ("Strahlige +Gallert") enveloping the whole body. The peculiar structure of the soft +body, particularly the "area porosa" on the basal pole of the central +capsule, and the pseudopodial cone within it, were first accurately +described by Hertwig (in 1879). A great number of simple rings, similar to +these, were found in the Challenger collection, and are here arranged in +six genera and forty-eight species. + +The simple ring of silex, which alone forms the skeleton of the Stephanida, +corresponds to the primary or sagittal ring of the other #Stephoidea#, and +lies therefore vertically in the median or sagittal plane of the body. We +can therefore distinguish on it four different segments, rods or bows, two +of which are more horizontal, two more vertical. The former are one upper +bow or apical rod, and one lower bow or basal rod. The latter are one +posterior bow or dorsal rod, and one anterior bow or ventral rod. Sometimes +each of these four component bows is distinguished by a corner-spine, or by +a pair of divergent branches. + +In the two simplest (and probably oldest) genera of Stephanida, in +_Archicircus_ and _Lithocircus_, the dorsal and ventral rods of the ring +are equal and cannot be distinguished; therefore the fundamental form is +here amphithect, diphragmatic, or biradial (the poles of the sagittal axis +being equal). In the four other genera the dorsal rod is more straight +(often vertical) and more or less different from the ventral, convexly +curved rod; therefore the fundamental form is here dipleuric or bilateral, +as in the greater number of all NASSELLARIA (the poles of the sagittal axis +being unequal). The general form of the ring in this latter case is +commonly obliquely ovate or nearly triangular, the basal pole being more +pointed, the apical pole more rounded (Pl. 81). + +The rods or bows of the ring are either roundish or cylindrical (with +circular or elliptical transverse section), or they are prismatic or +angular (commonly with triangular transverse section). In the latter case +one edge usually is prominent in the sagittal plane (on the convex outside +of the ring), whilst two other edges diverge laterally on both sides of it. +The inner or concave margin of the ring is commonly smooth. + +The inner perimeter of the large gate, enclosed by the ring, is commonly +rounded (elliptical or ovate), rarely angular. However, the outer perimeter +of the ring is {939}nearly always polygonal, with prominent corners, and +usually from these arise thorns or branched spines which are regularly +disposed. Regarding this disposition we may distinguish three cases: A, the +spines lie in the sagittal plane and form a single row, arising from the +median edge; B, the spines lie on both sides of the latter and form two +parallel rows, arising from the two lateral edges; C, the spines represent +a combination of A and B, and are disposed in three rows, two paired rows +arising from the two lateral edges, and an odd middle row between them, +arising from the median edge. The spines are simple, without branches, in +_Archicircus_ and _Zygocircus_; more or less branched in _Lithocircus_ and +_Dendrocircus_. The branches are often richly ramified or arborescent, and +exhibit great variety in size, special form, and direction (compare Pl. +81). + +The number and disposition of the spines or groups of spines are usually +constant, and may be employed in the further progress of our knowledge, to +distinguish a number of genera and subgenera. Very commonly (perhaps in the +majority of the Stephanida) we find six groups of spines, an apical group +on the upper rod of the sagittal ring, a basal group on the lower rod (on +the porochora of the central capsule), two ventral groups on the anterior +rod, and two dorsal groups on the posterior rod. In other species we find +four or eight groups instead of six, and sometimes a larger number. + +The most important of these apophyses of the ring are the basal spines, +arising from its basal pole, where the porochora of the central capsule +rests upon it. They are often much larger and more branched than the other +spines, and attain a peculiar morphological value in the small subfamily +Cortinida. Here we find three or four regularly disposed "basal spines," +which may be compared to the typical "basal feet" of the #Cyrtellaria#, +appearing in the majority of #Spyroidea# and #Cyrtoidea#. _Cortina_, one of +the most important NASSELLARIA, bears three typical divergent feet on the +base of the simple ring, two paired anterior or "pectoral feet," and an odd +posterior or "caudal foot." The latter appears as a direct basal +prolongation of the dorsal rod of the ring, and is opposed to an upper +prolongation of the same, which corresponds to the "apical horn" of the +#Cyrtellaria# (Pl. 97, figs. 1-3). As already explained above, these three +basal feet of _Cortina_ possess the highest phylogenetic value, since they +may also be compared with the three primary radial spines of the +#Plectoidea#, and so connect the #Cyrtellaria# and the #Plectellaria#. +_Stephanium_ differs from _Cortina_ in the possession of four basal feet, +an odd anterior or "sternal foot" being added to the three typical feet of +the latter (Pl. 92, figs. 20, 21). Some forms of #Plectoidea# +(_Plagoniscus_, _Plectaniscus_, &c.) seem to be nearly related to these +Cortinida, and may be easily transformed into them by development of a +complete ring, embracing the central capsule. They seem to demonstrate the +near affinity of all these triradiate NASSELLARIA (Pl. 91, figs. 4, 5, 9, +10). + +{940}_Synopsis of the Genera of Stephanida._ + + ------------------------------------------------------------------------- + I. Subfamily Lithocircida. + No typical basal feet on the base of the ring (no cortinar feet). + ------------------------------------------------------------------------- + Ring diphragmatic or { Ring smooth or thorny, + amphithect; dorsal { without branched spines. 401. _Archicircus_. + and ventral bow { + equal. { Ring armed with branched + { spines, 402. _Lithocircus_. + + Ring dipleuric, { Ring smooth or thorny, + bilateral; dorsal { without branched spines, 403. _Zygocircus_. + and ventral bow { + different. { Ring armed with branched 404. _Dendrocircus_. + { spines. + ------------------------------------------------------------------------- + II. Subfamily Cortinida. + Three or four typical basal feet on the ring (cortinar feet). + ------------------------------------------------------------------------- + Three basal feet (and { One caudal and two lateral + an apical horn). { feet, 405. _Cortina_. + + Four basal feet (and { Two sagittal and two + an apical horn). { lateral feet, 406. _Stephanium_. + + + +Subfamily 1. LITHOCIRCIDA, Haeckel. + +_Definition_.--#Stephanida# without typical basal feet or cortinar feet. + + + +Genus 401. _Archicircus_,[20] n. gen. + +_Definition_.--#Stephanida# with a simple amphithect or diphragmatic ring, +smooth or thorny, without branched spines and basal feet. + +The genus _Archicircus_ is the most primitive and simplest form of all +#Stephoidea#, and probably the common ancestral form, not only of this +suborder, but of the greater number of all NASSELLARIA (compare above, p. +893). The skeleton consists only of a quite simple sagittal ring, in which +commonly a slight difference of both poles of the main axis (basal and +apical pole) is visible, but no difference between the dorsal and the +ventral bow of the ring. In my Prodromus (1881, p. 447) the species of +_Archicircus_ were disposed partly in the subgenus _Monostephus_, partly in +the genus _Lithocircus_. + + + +Subgenus 1. _Monostephus_, Haeckel, 1881, Prodromus, p. 447. + +_Definition._--Ring circular, elliptical, or ovate, without prominent +corners. + + +1. _Archicircus princeps_, n. sp. + +Gate circular. Ring circular, smooth, its transverse section also circular. +The simplest form of all #Stephoidea#. + +_Dimensions._--Diameter of the gate 0.05 to 0.08; thickness of the ring +0.006 to 0.008. + +_Habitat._--Central Pacific, Stations 265 to 274, depth 2350 to 2925 +fathoms. + + +{941}2. _Archicircus monostephus_, n. sp. (Pl. 83, fig. 17). + +Gate circular. Ring circular, with three elegantly denticulate edges (one +outer median and two lateral edges). Transverse section of the ring +triangular. + +_Dimensions._--Diameter of the gate 0.06 to 0.08; thickness of the ring +0.01 to 0.008. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + +3. _Archicircus ellipsis_, n. sp. + +Gate elliptical. Ring elliptical, on the inner margin smooth, on the outer +margin with fifteen to twenty equal, short, simple, or slightly forked +thorns. Transverse section ovate. + +_Dimensions._--Diameter of the gate 0.05 to 0.09; thickness of the ring +0.01 to 0.014. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms; also +fossil in Barbados. + + +4. _Archicircus ovalis_, n. sp. + +Gate ovate. Ring elliptical, smooth, with three prominent, slightly +distorted edges, without thorns; in the transverse section triangular. + +_Dimensions._--Diameter of the gate 0.08 to 0.12; thickness of the ring +0.006 to 0.009. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + +5. _Archicircus monopylus_, n. sp. + +Gate ovate. Ring ovate, thorny, with three distorted edges, in the +transverse section triangular; surface covered with numerous simple small +thorns arising from the three edges. + +_Dimensions._--Diameter of the gate 0.1 to 0.15; thickness of the ring 0.01 +to 0.012. + +_Habitat._--Indian Ocean (Madagascar), Rabbe, surface. + + + +Subgenus 2. _Archistephus_, Haeckel. + +_Definition._--Ring polygonal, with four to six or more prominent corners +(and commonly with simple spines arising from the corners). + + +6. _Archicircus quadratus_, n. sp. + +Gate square. Ring square, with three edges and four short simple pyramidal +spines on the four corners, opposite in pairs in two perpendicular +diameters. Transverse section triangular. + +_Dimensions._--Diameter of the gate 0.08; thickness of the ring 0.008. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +{942}7. _Archicircus rhombus_, n. sp. (Pl. 81, fig. 7). + +Gate rhombic. Ring rhombic, with four prominent edges and four pairs of +short, divergent, pyramidal spines on the four corners, arising from the +lateral edges of the four rods, about as long as the radius of the gate. + +_Dimensions._--Diameter of the gate 0.04 to 0.08; thickness of the ring +0.007 to 0.01. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +8. _Archicircus duodenus_, n. sp. + +Gate square or rhombic. Ring rhombic, with three prominent edges and twelve +stout and straight pyramidal spines, about as long as the radius of the +gate. In each of the four corners are three divergent spines, arising from +the three edges of each two meeting rods. + +_Dimensions._--Diameter of the gate 0.08; thickness of the ring 0.012. + +_Habitat._--North Atlantic, surface (Rabbe). + + +9. _Archicircus primordialis_, n. sp. (Pl. 81, fig. 1). + +Gate ovate. Ring hexagonal, with three prominent edges and six short +pyramidal thorns at the six corners; the basal thorn is either simple or +forked. + +_Dimensions._--Diameter of the gate 0.07; thickness of the ring 0.01 to +0.015. + +_Habitat._--Central Pacific, Stations 265 to 274, depth 2350 to 2925 +fathoms. + + +10. _Archicircus hexacanthus_, n. sp. (Pl. 81, fig. 4). + +Gate subregular, hexagonal. Ring hexagonal, with three sharp edges and six +equal radial pyramidal spines, arising from the six corners and placed in +the plane of the ring, about as long as the diameter of the gate. + +_Dimensions._--Diameter of the gate 0.05 to 0.07; thickness of the ring +0.01. + +_Habitat._--South Pacific, Station 295, depth 1500 fathoms. + + +11. _Archicircus hertwigii_, Haeckel. + + _Lithocircus annularis_, R. Hertwig (_non_ J. Mueller), 1879, Organismus + der Radiol., p. 69. Taf. vii. fig. 5. + +Gate hexagonal, with prolonged main axis. Ring hexagonal, with two +prominent edges and six pairs of equal, short, conical spines, arising from +the two edges of the six rods at the six corners and divergent on each side +of the plane of the ring. The basal spine-pair is doubled, therefore there +are in all fourteen spines. + +_Dimensions._--Diameter of the gate 0.05 to 0.07; thickness of the ring +0.005 to 0.006. + +_Habitat._--Mediterranean (Messina), Hertwig, surface. + + +{943}12. _Archicircus triglyphus_, n. sp. + +Gate ovate. Ring hexagonal, with three prominent edges and twenty-two to +twenty-four simple curved spines, arising from the six corners and about as +long as the diameter of the gate. In the basal corner arise six to nine +larger spines, protecting the basal pole of the central capsule. From each +of the five other corners arise three spines, diverging from the three +edges. + +_Dimensions._--Diameter of the gate 0.07 to 0.11; thickness of the ring +0.008 to 0.011. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +13. _Archicircus sexangularis_, n. sp. (Pl. 81, fig. 12). + +Gate hexagonal or subcircular. Ring hexagonal, with two sharp prominent +edges and six pairs of divergent spines, about as long as the radius of the +gate, and arising from the two edges at the six corners. The two apical and +the two basal spines are simple and conical, whilst the eight other spines, +arising in pairs from the two dorsal and the two ventral corners, are +slightly forked. + +_Dimensions._--Diameter of the gate 0.06 to 0.08; thickness of the ring +0.01 to 0.015. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + + +Genus 402. _Lithocircus_,[21] J. Mueller, 1856, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 484. + +_Definition._--#Stephanida# with a simple amphithect or diphragmatic ring, +armed with branched spines, without typical basal feet. + +The genus _Lithocircus_ is the oldest known form of all #Stephoidea#, +founded by J. Mueller in 1856 for his _Lithocircus annularis_, the first +species of this suborder described. We retain here this cosmopolitan form +as the typical representative of the genus, which differs from the +preceding _Archicircus_, its ancestral form, in the development of branched +radial spines. + + +1. _Lithocircus annularis_, J. Mueller. + + _Lithocircus annularis_, J. Mueller, 1858, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 29, Taf. i. fig. 1. + +Gate circular. Ring circular, with four forked or simply branched spines, +opposite in pairs in two diameters, perpendicular one to the other. Spines +with slender curved fork-branches, about as long as the diameter of the +gate. The specimen figured by J. Mueller bears a supernumerary fifth spine; +numerous other specimens observed by me exhibited a regular cross of four +spines. + +_Dimensions._--Diameter of the gate 0.1 to 0.15; length of the spines 0.01 +to 0.18. + +_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Indian, Pacific, +surface. + + +{944}2. _Lithocircus quadricornis_, n. sp. (Pl. 81, fig. 9). + +Gate square. Ring square, with three sharp denticulate edges, and four +large bunches of richly branched spines on the four corners. In each corner +arise three curved spines, about as long as the diameter of the ring; their +numerous irregular branches are forked and curved like the antlers of deer. + +_Dimensions._--Diameter of the gate 0.07; length of the horns 0.06 to 0.09. + +_Habitat._--South Pacific, Station 300, depth 1375 fathoms. + + +3. _Lithocircus decimalis_, n. sp. (Pl. 81, fig. 15). + +Gate elliptical. Ring pentagonal, with three prominent edges and five pairs +of branched spines on the five corners. In each corner arise two or three +curved spines, about as long as the radius of the gate, each with two to +four forked branches. + +_Dimensions._--Diameter of the gate 0.08; length of the spines 0.03 to +0.05. + +_Habitat._--North Atlantic, Station 354, surface. + + +4. _Lithocircus hexablastus_, n. sp. (Pl. 81, fig. 17). + +Gate elliptical. Ring hexagonal, with three prominent edges and six pairs +of branched spines, arising from the six corners. Each of the twelve spines +is short and stout, only half as long as the radius of the gate, and bears +a bunch of ten to twenty short, densely aggregated, conical or horn-like +curved branches. + +_Dimensions._--Diameter of the gate 0.1; length of the spines 0.02 to 0.03. + +_Habitat._--Central Pacific, Stations 265 to 268, depth 2700 to 2900 +fathoms. + + +5. _Lithocircus crambessa_, n. sp. (Pl. 81, fig. 6). + +Gate elliptical or subcircular. Ring hexagonal, with three wing-shaped +distorted edges and six groups of branched spines, arising from the six +corners. In each corner arise three short and stout divergent spines, each +bearing a bunch of numerous short roundish branches like a cauliflower, +scarcely as long as the thickness of the ring. + +_Dimensions._--Diameter of the ring 0.1 to 0.12, length of the spines 0.01 +to 0.02. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +6. _Lithocircus tarandus_, n. sp. (Pl. 92, fig. 19). + +Gate circular. Ring hexagonal, with three sharp edges and six pairs of +large branched spines, arising from the flat lateral edges on the six +corners. Each of the twelve spines is horizontally expanded, longer than +the diameter of the ring and dichotomously forked like the antlers of a +{945}reindeer. If the lateral ends of the branches of this species become +united in the frontal plane, we get _Microcubus_, the four upper spines +forming the mitral ring, the four middle the equatorial ring, and the four +lower the basal ring. + +_Dimensions_.--Diameter of the gate 0.08; length of the spines 0.09. + +_Habitat_.--Central Pacific, Station 272, surface. + + +7. _Lithocircus furcatus_, n. sp. + +Gate ovate. Ring ovate, with three sharp prominent edges. The two lateral +edges are smooth. The median edge (in the sagittal plane) bears sixteen to +twenty forked spines (commonly eight dorsal, eight ventral, and four +basal). All the spines are of nearly equal size, slightly curved, and about +half as long as the short sagittal axis of the ring. + +_Dimensions_.--Diameter of the gate 0.08 to 0.12; length of the spines 0.03 +to 0.04. + +_Habitat_.--North Pacific, Station 253, depth 3125 fathoms. + + +8. _Lithocircus magnificus_, n. sp. (Pl. 81, fig. 16). + +Gate ovate or nearly elliptical. Ring ovate, with three prominent edges, +and numerous richly branched spines arising from the three edges. The +specimen figured, which I observed living in the Mediterranean, exhibited +eight bunches of larger spines, three dorsal, three ventral, one apical, +and one basal bunch; the latter much larger than the seven others. Each +bunch was composed of two to four larger and numerous smaller spines, their +branches curved and forked. The ovate purple central capsule, with a +distinct podoconus, filled more than the half of the gate. + +_Dimensions_.--Diameter of the gate 0.1 to 0.13; length of the spines 0.05 +to 0.15. + +_Habitat_.--Mediterranean (Portofino, 1880), Atlantic (Canary Islands), +Station 354, surface. + + + +Genus 403. _Zygocircus_,[22] Buetschli, 1882, Zeitschr. f. wiss. Zool., +vol. xxxvi. p. 496. + +_Definition_.--#Stephanida# with a simple dipleuric or bilateral ring, +smooth or thorny, without branched spines and basal feet. + +The genus _Zygocircus_ and the following _Dendrocircus_ differ from the two +preceding older genera in the bilaterally symmetrical or dipleuric form of +the sagittal ring. Whilst in _Archicircus_ and _Lithocircus_ the two +sagittal halves or bows of the ring, the dorsal and ventral bow, are equal +(therefore the fundamental form amphithect or diphragmatic), here both bows +become distinctly different; the dorsal bow is constantly more straight +(often vertical), the ventral bow more convex (obliquely ascending). This +dipleuric differentiation is most important, as it is transmitted to the +greater number of NASSELLARIA by heredity. + + +{946}1. _Zygocircus sagittalis_, n. sp. + +Gate ovate. Ring half ovate or nearly triangular, with three curved edges +and three prominent corners, one apical and two basal protuberances. Dorsal +rod vertical, twice as long as the horizontal basal rod. Ventral rod +convexly curved. + +_Dimensions._--Diameter of the gate 0.05 to 0.07; height of the tubercles +0.01 to 0.015. + +_Habitat._--Central Pacific, Stations 265 to 268, depth 2900 fathoms. + + +2. _Zygocircus trigonus_, n. sp. + +Gate triangular. Ring triangular, with three curved edges and three +prominent corners, which are prolonged into nine divergent conical spines; +three spines arising from the three edges of each corner. Dorsal rod +vertical; ventral and basal rods curved and convergent. + +_Dimensions._--Diameter of the gate 0.11 to 0.13; length of the spines 0.01 +to 0.015. + +_Habitat._--Indian Ocean, Sunda Archipelago (Rabbe), surface. + + +3. _Zygocircus tetragonus_, n. sp. + +Gate ovate. Ring quadrangular, without edges, with four simple conical +spines of different sizes; one smaller apical, one larger basal, and two +equatorial spines of middle size (one dorsal and one ventral). Dorsal and +ventral rod curved. + +_Dimensions._--Diameter of the gate 0.04 to 0.06; length of the spines +0.018 to 0.026. + +_Habitat._--Tropical Atlantic, Station 338, depth 1990 fathoms. + + +4. _Zygocircus rhombicus_, n. sp. + +Gate rhombic. Ring rhombic, with three prominent edges, and eight short +conical curved spines arising from the lateral edges at the four corners of +the rhombus. The basal and ventral spine are larger than the apical and +dorsal spine; the ventral rod is more curved (with smaller angle) than the +shorter dorsal rod. The medial edge of the ring is smooth, without spines. + +_Dimensions._--Diameter of the gate 0.08; length of spines 0.02 to 0.04. + +_Habitat._--South Atlantic, Station 335, depth 1425 fathoms. + + +5. _Zygocircus pentagonus_, n. sp. (Pl. 81, fig. 8). + +Gate roundish pentagonal. Ring very thick (about as thick as the radius of +the gate), irregularly pentagonal, with prominent sagittal edge. On both +sides of the latter arise at the five corners five pairs of short simple +irregularly curved spines. The four ventral spines are larger than the four +dorsal, and the two basal spines larger than the eight former, forked. (In +fig. 8 the basal spines are turned upwards.) + +_Dimensions._--Diameter of the gate 0.07; length of the spines 0.04 to +0.06. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +{947}6. _Zygocircus hexagonus_, n. sp. + +Gate irregularly hexagonal. Ring obliquely hexagonal, thick, without edges, +with six short and stout conical spines on the six corners. The two spines +of the curved ventral rod are longer than the two spines of the straight +dorsal rod. The apical spine is smaller and the basal spine larger than the +four others. + +_Dimensions_.--Diameter of the gate 0.07 to 0.09; length of the spines 0.01 +to 0.03. + +_Habitat_.--North Pacific, Station 241, depth 2300 fathoms. + + +7. _Zygocircus triquetrus_, n. sp. (Pl. 81, fig. 3). + +Gate obliquely ovate. Ring obliquely hexagonal, with three sharp edges and +three short conical spines on each of the six corners. Therefore each +hexagonal edge bears six short radial spines of equal size. + +_Dimensions_.--Diameter of the gate 0.04 to 0.08; length of the spines 0.01 +to 0.02. + +_Habitat_.--Cosmopolitan; Mediterranean, Atlantic, Pacific, surface. + + +8. _Zygocircus dodecanthus_, n. sp. + +Gate semicircular. Ring semicircular or irregularly hexagonal, without +edges, with twelve short blunt spines, arising in pairs from the six +corners; two apical, two basal, and between them two equatorial corners. +Three pairs of spines remain on the straight dorsal rod, three on the +curved ventral rod. + +_Dimensions_.--Diameter of the gate 0.04 to 0.06; length of the spines 0.01 +to 0.02. + +_Habitat_.--Central Pacific, Stations 263 to 268; depth 2650 to 2900 +fathoms. + + +9. _Zygocircus acacia_, n. sp. (Pl. 81, fig. 5). + +Gate obliquely ovate. Ring semi-ovate, with straight dorsal and curved +ventral rod, partly with distorted edges. Six bunches of numerous short and +straight conical spines arise from the ring, one larger bunch (often +trifid) from the apex, two smaller bunches from the dorsal, two from the +ventral rod, and one very large bunch from the base. The six bunches are +often more separated, smaller, and the spines shorter than in the figured +specimen, which passes over into _Dendrocircus_. + +_Dimensions_.--Diameter of the gate 0.12 to 0.16; length of the spines, +0.01 to 0.07. + +_Habitat_.--Central Pacific, Station 266, depth 2750 fathoms. + + +10. _Zygocircus polygonus_, n. sp. (Pl. 81, fig. 2). + +Gate irregularly roundish or ovate. Ring irregularly polygonal or sometimes +nearly circular, without edges, armed with a single series of ten to +fifteen short pyramidal spines, which are irregularly {948}disposed in the +sagittal plane. The ventral rod is strongly curved, often semicircular, the +dorsal rod less curved or nearly straight. + +_Dimensions_.--Diameter of the gate 0.05 to 0.07; length of the spines +0.004 to 0.02. + +_Habitat_.--Cosmopolitan--Atlantic, Pacific; also fossil in Barbados. + + +11. _Zygocircus buetschlii_, n. sp. + + _Zygocircus productus_, Buetschli, 1882, Zeitschr. f. wiss. Zool., vol. + xxxvi. p. 497. + +Gate obliquely ovate. Ring irregularly roundish, semi-ovate or ovate, with +interrupted and distorted edges, and with a large number (ten to twenty or +more) of simple, irregularly formed and asymmetrically disposed spines; +commonly some larger spines at the base. + +_Dimensions_.--Diameter of the gate 0.05 to 0.09; length of the spines +0.005 to 0.02. + +_Habitat_.--Fossil in Barbados. + + +12. _Zygocircus productus_, Buetschli. + + _Zygocircus productus_, Buetschli, 1882, Zeitschr. f. wiss. Zool., vol. + xxxvi p. 496. + + _Lithocircus productus_, R. Hertwig, 1879, Organismus d. Radiol., p. 69, + Taf. vii. fig. 4. + +Gate obliquely ovate. Ring obliquely ovate, with three complete prominent +edges and with numerous (ten to twenty or more) simple, short conical +spines, arising in three series from the three edges; commonly some smaller +spines at the base. + +_Dimensions_.--Diameter of the gate 0.1 to 0.2; length of the spines 0.005 +to 0.02. + +_Habitat_.--Cosmopolitan; Mediterranean, Atlantic, Pacific, surface. + + + +Genus 404. _Dendrocircus_,[23] Haeckel, 1881, Prodromus, p. 447. + +_Definition_.--#Stephanida# with a simple dipleuric or bilateral ring, +armed with branched spines, without typical basal feet. + +The genus _Dendrocircus_ has the same dipleuric or bilaterally symmetrical +form of the sagittal ring as its ancestral genus _Zygocircus_. It differs +from the latter in the development of branched radial spines, and therefore +bears to it the same relation as the amphithect _Lithocircus_ does to the +simpler _Archicircus_. + + +1. _Dendrocircus quadrangulus_, n. sp. + +Gate irregularly quadrangular or nearly semicircular. Ring quadrangular, +edgeless, with four unequal sides; ventral rod more curved and with longer +sides than the dorsal rod. From the four edges arise four strong, +irregularly branched spines, about as long as the diameter of the gate, +{949}with curved branches; the ventral and basal spines larger than the +dorsal and apical spines. Similar to _Lithocircus quadricornis_ (Pl. 81, +fig. 9), but less branched, and with a striking difference between the +shorter dorsal and the longer ventral rod. + +_Dimensions._--Diameter of the gate 0.04 to 0.06; length of the spines 0.05 +to 0.07. + +_Habitat._--North Pacific, Station 256, depth 2950 fathoms. + + +2. _Dendrocircus dodecarrhiza_, n. sp. + +Gate obliquely ovate. Ring irregularly quadrangular, with three prominent +edges. From the latter arise at the four corners twelve divergent, +irregularly branched spines (three in each corner), about as long as the +radius of the gate, with curved branches; the three basal spines larger +than the nine others. + +_Dimensions._--Diameter of the gate 0.08 to 0.1; length of the spines 0.04 +to 0.06. + +_Habitat._--Indian Ocean (Maldive Islands), surface (Haeckel). + + +3. _Dendrocircus dodecancistra_, n. sp. (Pl. 81, fig. 11). + +Gate obliquely ovate or nearly elliptical. Ring irregularly ovate, with +three distorted edges and six pairs of branched spines. The two ventral +pairs are much more distant than the two dorsal pairs, the ventral rod +being longer and more curved than the dorsal rod. All twelve spines are of +nearly equal size, are more or less curved, about as long as the diameter +of the gate, and each bears six to twelve irregular short branches at the +end. + +_Dimensions._--Diameter of the gate 0.07 to 0.08; length of the spines 0.05 +to 0.08. + +_Habitat._--Tropical Atlantic, Station 342, depth 1445 fathoms. + + +4. _Dendrocircus arborescens_, n. sp. (Pl. 81, fig. 10). + +Gate irregularly roundish or nearly circular. Ring of the same form, with +slight edges and six pairs of elegant arborescent spines (one apical, two +dorsal, two ventral, and one basal pair); the three latter somewhat larger +than the three former. Each tree is larger than the ring, in the basal half +simple, in the distal half forked, each fork-branch with numerous +dichotomous terminal branches. + +_Dimensions._--Diameter of the gate 0.06 to 0.08; length of the spines 0.12 +to 0.15. + +_Habitat._--Central Pacific, Stations 266 to 274, surface. + + +5. _Dendrocircus elegans_, n. sp. (Pl. 81, fig. 13). + +Gate irregularly ovate. Ring thick, ovate, with three denticulate edges and +six bunches of stout, branched and spinulate, curved spines. The four +ventral spines are more distant than the four dorsal, the ventral rod being +more curved than the dorsal. The latter bears above the two apical spines. +The two basal spines are much larger, deeply forked; their four +fork-branches may be compared to the four basal feet of _Stephanium_. + +_Dimensions._--Diameter of the ring 0.09 to 0.11; length of the spines 0.03 +to 0.06. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + +{950}6. _Dendrocircus barbadensis_, n. sp. + +Gate irregularly ovate or nearly semicircular. Ring of the same oblique +form, thick, with interrupted and distorted edges, armed with eight to +twelve larger irregularly formed and branched acute spines; between them +numerous conical smaller spines. This common species is very polymorphous +and variable. + +_Dimensions._--Diameter of the ring 0.05 to 0.08; length of the spines +0.005 to 0.02. + +_Habitat._--Fossil in Barbados. + + +7. _Dendrocircus stalactites_, n. sp. (Pl. 81, fig. 14). + +Gate obliquely ovate. Ring irregularly ovate or roundish, very thick, +without edges, armed with numerous (eight to twelve or more) short and +stout branches, which are shorter than the diameter of the gate, +irregularly disposed and branched, with very numerous clustered blunt +ramules. + +_Dimensions._--Diameter of the gate 0.07 to 0.09; length of the spines 0.02 +to 0.06. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + + +Subfamily 2. CORTINIDA, Haeckel. + +_Definition._--#Stephanida# with typical basal feet (or cortinar feet). + + + +Genus 405. _Cortina_,[24] n. gen. + +_Definition._--#Stephanida# with a simple dipleuric or bilateral ring, +bearing at the base three divergent feet (one odd caudal and two paired +lateral feet). + +The genus _Cortina_ and the following _Stephanium_ represent together the +small but very important group of Cortinida, differing from the simple +Lithocircida in the possession of three typical basal feet, which are +transmitted to the majority of the NASSELLARIA by heredity, and produce +their peculiar triradial structure. They appear therefore as a combination +of the simple ring (_Zygocircus_) with three basal feet (_Plagonium_). One +of these three divergent feet is the odd caudal foot, opposite to the +apical horn; the two others are the paired lateral or pectoral feet. (On +the probable origin and the typical signification of _Cortina_ compare +above, pp. 891-894.) + + +1. _Cortina tripus_, n. sp. (Pl. 83, fig. 9). + +Ring ovate, smooth, or with a few short thorns. Apical horn oblique, +curved, simple, smooth, about as long as the sagittal axis of the ring. +Feet divergent, curved, simple, smooth, about as {951}long as the horn; the +caudal foot shorter than the two pectoral feet. Very variable in form and +size. + +_Dimensions._--Height of the ring 0.06 to 0.09, breadth 0.04 to 0.06; +length of the feet 0.05 to 0.1. + +_Habitat._--Cosmopolitan; Atlantic, Indian, Pacific, surface and in various +depths. + + +2. _Cortina typus_, n. sp. (Pl. 97, fig. 1). + +Ring kidney-shaped or nearly semicircular, with revolute vertical dorsal +rod and strongly curved ventral rod; both rods with two pairs of +spine-bunches. Apical horn nearly straight, thorny, longer than the ring, +directed a little obliquely backwards. Feet slightly curved, of equal +length, two to three times as long as the ring; each armed with few large +bunches of curved spines, which are more developed in the caudal foot than +in the two pectoral feet. + +_Dimensions._--Height of the ring 0.14, breadth 0.08; length of the feet +0.2 to 0.3. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms. + + +3. _Cortina conifera_, n. sp. + +Ring subcircular, smooth. Apical horn and the three divergent feet of equal +size and similar form, cylindrical, straight, about as long as the ring, at +the distal end thickened, with a dimply cone (similar to _Tripospyris +conifera_ and _Tripospyris eucolpa_, Pl. 84, figs. 4, 7). + +_Dimensions._--Height of the ring 0.08, breadth 0.06; length of the feet +0.09. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +4. _Cortina furcata_, n. sp. + +Ring elliptical, with three forked horizontal spines (one on the dorsal and +two on the ventral rod). Apical horn and the three divergent feet of equal +size, somewhat longer than the ring, slightly curved, in the distal half +forked. + +_Dimensions._--Height of the ring 0.07, breadth 0.05; length of the feet +0.09. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. Fossil in +Barbados. + + +5. _Cortina dendroides_, n. sp. + +Ring ovate, with six pairs of branched horizontal spines, three on the +dorsal and three on the ventral rod. Apical horn very large, arborescent, +about as long and as broad as the ring. Feet similar to the horn, also +richly branched, of equal size. All the rods and their branches curved, +with prominent distorted edges. + +_Dimensions._--Height of the ring 0.13 to 0.17, breadth 0.1 to 0.12; length +of the feet 0.15 to 0.2. + +_Habitat._--Central Pacific, Stations 266 to 274, depth 2350 to 2925 +fathoms. + + +{952}6. _Cortina cervina_, n. sp. (Pl. 92, fig. 21). + +Ring ovate, with four pairs of forked horizontal spines (two dorsal and two +ventral pairs). Apical horn straight and stout, as long as the ring, with +trifid point. Three feet equal, widely divergent, very large, branched like +a deer's antler, with very numerous short and stout, curved and pointed +branches. All rods and branches roundish, without edges. + +_Dimensions._--Height of the ring 0.1, breadth 0.07; length of the feet +0.12 to 0.16. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + + +Genus 406. _Stephanium_,[25] n. gen. + +_Definition._--#Stephanida# with a simple dipleuric or bilateral ring, +bearing at the base four divergent feet (two sagittal and two lateral +feet). + +The genus _Stephanium_ differs from the preceding nearly allied _Cortina_ +in the production of four basal feet; the new foot, missing in the latter, +is the anterior or sternal foot. Therefore _Stephanium_ may be regarded as +the archetype of all those NASSELLARIA in which, on the base of the +sagittal ring, there are developed four typical feet--two sagittal feet +(the posterior caudal and anterior sternal foot) and two lateral feet +(right and left). On the origin of _Stephanium_ compare above, p. 893, &c. + + +1. _Stephanium quadrupes_, n. sp. (Pl. 92, fig. 20). + +Ring ovate, with three prominent dentate edges and a short pyramidal apical +horn. Four feet all of nearly equal size, about as long as the ring, also +with three thorny edges, in the upper half divergent, in the lower +convergent. + +_Dimensions._--Height of the ring 0.12, breadth 0.08; length of the feet +0.11 to 0.13. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +2. _Stephanium tetrapus_, n. sp. + +Ring elliptical, without edges, thorny, with a stout, thorny apical horn of +the same length. Four feet curved and irregularly branched, divergent, of +different size. The two sagittal feet (the anterior sternal and posterior +caudal) about as long as the ring. The two lateral feet (right and left) +nearly twice as long, more richly branched. + +_Dimensions._--Height of the ring 0.16, breadth 0.11; length of the feet +0.15 to 0.3. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. Fossil in +Barbados. + + + +{953}Family XLIX. #SEMANTIDA#, n. fam. + +_Definition._--#Stephoidea# with a single vertical ring (the primary +sagittal ring), bearing on its base a horizontal ring (basal or cortinar +ring) with two to four or more basal gates (or cortinar pores). + +The family #Semantida# differs from the preceding Stephanida in the +development of a small horizontal ring on the base of the primary vertical +sagittal ring. By the crossing of these two rings a small latticed basal +plate is formed, with one or two pairs of pores; rarely with a greater +number of "basal pores." The production of this characteristic "basal +plate" is of the greatest morphological importance, as the beginning of the +numerous different lattice-formations, which are differentiated in the +great majority of NASSELLARIA. + +In my Prodromus (1881, p. 446) I had enumerated the Semantida with three +genera (Nos. 298 to 300) as a separate subfamily of the Dyostephida or +"Stephoidea biannularia," and characterised these "Dyostephanida" by the +following definition: "Skeleto annulis duobus composito, qui in duobus +planis invicem perpendicularibus jacent; altero annulo (sagittali) +verticali, altero (basali) horizontali." As the names there given were +already employed with another signification, and as the Zygostephanida +(there united with the Dyostephanida) are more closely related to the +Coronida, I now change the names, and propose to call the family Semantida, +expressing by this term the typical similarity of the skeleton to a +signet-ring (_Semantis_, _Semantrum_, _Semantidium_). + +At about the same time, some #Stephoidea# of this family were accurately +described by Buetschli (1882, Zeitschr. f. wiss. Zool., vol. xxxvi. p. 495, +Taf. xxxii. figs. 6, 7, 8). He called them _Stephanolithis_, a name which +Ehrenberg had employed, not for complete shells of Radiolaria, but for +isolated parts of such, and for siliceous fragments of different skeletons, +needles of Sponges, &c. The three species described by Buetschli represent +three different genera of our Semantida, viz., _Semantis spinescens_ (with +two gates in the basal plate), _Semantrum muelleri_ (with four gates), and +_Semantidium haeckelii_ (with six gates). He pointed out the great +morphological value of the fenestrated basal plate and its paired gates, as +beginnings of numerous other NASSELLARIA. But his opinion, that in all +#Spyroidea# and #Cyrtoidea#, derived from these, two pairs of basal gates +were constant, was erroneous, nor was the formation of the first pair +naturally explained; he supposed that the formation of the basal plate +begins by development of an odd sagittal apophysis, arising from the base +of the primary sagittal ring. But this odd sagittal apophysis ("der unpaare +mediane Kieselfortsatz c1", _loc. cit._, p. 497) is in reality not a +primary {954}and essential part of the skeleton, but secondary and of +little morphological value, absent in the majority of the Semantida and of +the other NASSELLARIA. + +We divide our family Semantida into two different subfamilies, which +possibly possess a direct phylogenetic relation to the two subfamilies of +Stephanida:--The Semantiscida have no typical feet, and have arisen +directly from the Lithocircida; the Cortiniscida, however, possess the +three typical basal feet of _Cortina_, and may therefore be derived +directly from the Cortinida. Since these three cortinar feet are probably +identical with the three primary radial rods of the #Plectoidea#, an +immediate affinity also to these NASSELLARIA is indicated. + +The Semantiscida, which do not possess these three basal cortinar feet, are +the simpler forms of the family. The simplest of all, and perhaps the +common ancestral form of the whole family, is _Semantis_ (Pl. 92, figs. 1, +2). It may be derived from _Archicircus_ or _Zygocircus_ by development of +two pairs of horizontal apophyses on its base, around the porochora of the +central capsule. The two rods of each side (right and left), becoming +curved one towards the other, and meeting laterally, form a simple +horizontal gate, and the two paired basal gates together, a horizontal ring +or basal ring, to which the primary sagittal ring is perpendicular. In the +next allied genus, _Semantrum_ (Pl. 92, figs. 3-5), three pairs of +horizontal apophyses are developed, and therefore two pairs of basal gates +produced, an anterior and a posterior. In the third genus, _Semantidium_ +(Pl. 92, figs. 6, 7), three pairs of basal pores or gates are visible, +surrounded and separated by four pairs of horizontal apophyses, which arise +from the base of the sagittal ring. Finally, in _Clathrocircus_ (Pl. 92, +figs. 8-10) the number of apophyses is much increased, and two parallel +rows of pores are developed along the two sides of the sagittal ring. + +The basal plate or the "seal," developed from the base of the primary +sagittal ring or "signet-ring," is therefore a horizontal ring, which +becomes bisected by the latter, and exhibits either one pair of primary +"basal gates" or two or three pairs of these important basal pores, rarely +more. Since these pores possess the greatest morphological value, and are +probably everywhere homologous, we give to them and to the separating +apophyses certain names, and call the anterior pair of gates, "jugular +pores" (_i_ in our figures, the pair I of Buetschli); the middle (usually +the largest) pair, "cardinal pores" (_k_ in our figures, the pair II of +Buetschli), and the posterior, smaller pair, "cervical pores," _l_. The +typical pairs of rods, by the union of which these basal pores arise, are +the following:--(1) the clavicular or furcular rods, _f_, the first pair +(rods _e_1 of Buetschli), (2) the coracal rods, _e_, between the jugular +and cardinal pores (rods _e_ of Buetschli), (3) the scapular rods, _g_, +between the cardinal and cervical pores (rods _e_2 of Buetschli), (4) the +cervical rods, the fourth pair of apophyses, the most posterior, _h_. +Buetschli supposes that the topographical succession of the three typical +pairs of basal pores is also the chronological succession, the jugular +being formed first, the {955}cardinal second and the cervical pores third +but it seems that this succession is often altered and that the cardinal +pores (the largest), appear first, the jugular pores (in front of them) +second and the cervical pores third (or perhaps sometimes in the inverse +succession). + +The Cortiniscida, the second subfamily of Semantida, differ from the +preceding Semantiscida in the possession of three typical basal feet, which +are probably inherited from the Cortinida, and perhaps indirectly from the +Plagonida (_Plagoniscus_). The simplest and the most important form of this +second family is _Cortiniscus_ (Pl. 92, figs. 11-13), differing from its +probable ancestral form, _Cortina_, in the development of a basal ring, +produced by horizontal union of the basal apophyses. The three typical feet +are the same as in all triradiate NASSELLARIA, two paired pectoral feet +(_p__{1}, _p__{11}) diverging on the anterior base of the sagittal ring, +whilst the odd caudal foot (_c_) lies on its posterior base in the sagittal +plane and appears as a basal prolongation of the dorsal rod of the sagittal +ring; the upper part of the dorsal rod is usually prolonged into an +ascending apical horn. In _Stephaniscus_ (Pl. 92, figs. 14, 15) four basal +feet are visible, an anterior or sternal foot (_z_) being added as a +prolongation of the basal rod of the ring, opposite to the caudal foot. +Finally, _Semantiscus_ (Pl. 92, figs. 16-18) is distinguished by the +possession of six divergent basal feet, probably identical with those of +all six-radiate NASSELLARIA; three of these may be regarded as primary and +perradial, the odd caudal and the paired pectoral feet; the three other +intercalated as secondary or interradial feet, the odd sternal (_z_) and +the paired tergal feet (_t__{1}, _t__{11}). + +The basal plate of these Cortiniscida exhibits the same important +differences as in the preceding Semantiscida, either one, or two, or three +pairs of basal gates being developed. But there occur also in some species +(mainly in _Cortiniscus_) only three basal gates, an odd anterior (between +the two pectoral feet and a connecting horizontal bar), and two paired +posterior (between the two pectoral and the odd caudal foot). It requires +further accurate researches to solve the important problem, what the true +homologies of these typical basal pores and the separating bars are in the +different genera of Semantida. In _Semantiscus_ there are three pairs of +basal pores in the horizontal seal, corresponding to those of _Semantidium_ +and the radial rods or bars between, these are the basal parts of the six +radial feet; therefore the odd caudal foot (_t_) seems to be the posterior, +and the odd sternal foot (_z_) the anterior prolongation of the basal part +of the primary sagittal ring; the two paired anterior or pectoral feet +(_p__{1}, _p__{11}) the prolongations of the coracal rods (_e_) and the two +paired posterior or tergal feet (_t__{1}, _t__{11}), the prolongations of +the scapular rods (_g_). But it is not yet certain whether these six radial +feet and the separating gates of the basal plate are all the same and truly +homologous in all six-radiate NASSELLARIA. In every case the comparative +study of the Semantida is of the highest value for the accurate knowledge +of the MONOPYLEA. + +{956}_Synopsis of the Genera of Semantida._ + + ------------------------------------------------------------------------- + I. Subfamily Semantiscida. + Basal ring without typical, regularly disposed basal feet + (no cortinar feet). + ------------------------------------------------------------------------- + { Two basal pores, 407. _Semantis_. + Only two, four, or six { + basal pores (no dorsal { Four basal pores, 408. _Semantrum_. + and ventral pores). { + { Six basal pores, 409. _Semantidium_. + + Besides four basal pores, also apical pores or + dorsal and ventral pores along the whole ring, 410. _Clathrocircus_. + ------------------------------------------------------------------------- + II. Subfamily Cortiniscida. + Basal ring with typical, regularly disposed basal feet + (cortinar feet). + ------------------------------------------------------------------------- + { One odd caudal foot and + Three basal feet. { two paired lateral + { feet, 411. _Cortiniscus_. + + { Two sagittal and two + Four basal feet. { lateral or pectoral + { feet, 412. _Stephaniscus_. + + { Two sagittal, two + Six basal feet. { pectoral, and two + { tergal feet, 413. _Semantiscus_. + + + +Subfamily 1. SEMANTISCIDA, Haeckel. + +_Definition._--#Semantida# without typical basal feet or cortinar feet. + + + +Genus 407. _Semantis_,[26] n. gen. + +_Definition._--#Semantida# with two basal pores (or jugular pores), without +typical basal feet. + +The genus _Semantis_, the most primitive and the oldest of the Semantida, +is of the greatest morphological interest, as the first form of +#Stephoidea# which produces gates or pores by communicating branches, and +therefore the probable ancestral form not only of this family, but of the +greater number of all #Stephoidea#, and perhaps even of all #Spyroidea# and +#Cyrtoidea#. _Semantis_ arises from _Archicircus_ by the production of two +pairs of lateral branches from the basilar rod of the sagittal ring, one +anterior pair of clavicular rods, and one posterior pair of coracal rods. +By junction of the clavicular and coracal rod on each side arises a left +and a right pore, the "jugular pore or jugular gate." + + +1. _Semantis biforis_, n. sp. (Pl. 92, fig. 2). + +Sagittal ring obliquely ovate, nearly trapezoidal, with six pairs of short +mammillated knobs or branches; dorsal rod straight, vertical, with two +pairs of knobs, ventral rod strongly convex, also with {957}two pairs of +knobs; two other pairs in the apical rod. Basilar rod horizontal, straight. +Basal ring with six pairs of similar knobs, three on each side. Basal gates +ovate or nearly triangular. + +_Dimensions._--Height of the sagittal ring 0.09, breadth 0.07. + +_Habitat._--Central Pacific, Stations 265 to 268, depth 2700 to 2900 +fathoms. + + +2. _Semantis distoma_, n. sp. + +Sagittal and basal ring nearly of the same form as in the preceding +species, but half as thick and armed with numerous branched spines which +are about half as long as the diameter of the main gate, and with thin and +curved pointed branches. + +_Dimensions._--Height of the sagittal ring 0.11, breadth 0.08. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +3. _Semantis dipyla_, n. sp. + +Sagittal ring kidney-shaped, very thick, with six pairs of short, thorny, +or irregularly tuberculated knobs (two dorsal, two apical, and two ventral +pairs). Basal ring smooth, scarcely half as thick, horizontal, with two +semicircular basal gates, about half as broad as the main gate. From the +two opposite lateral corners of the basal ring two slender upwardly curved +spines arise, resembling the basal part of a commencing frontal ring. + +_Dimensions._--Height of the sagittal ring 0.08, breadth 0.05. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +4. _Semantis sigillum_, n. sp. (Pl. 92, fig. 1). + +Sagittal ring elliptical, with four pairs of stout arborescent spines (two +apical and two equatorial pairs), which are irregularly branched and +forked, with numerous thin lateral branches. Apex with a short conical +trifid vertical horn. Basal ring thorny, with obliquely descending slightly +curved bars. + +_Dimensions._--Height of the sagittal ring 0.12, breadth 0.09. + +_Habitat._--South Pacific, Station 300, depth 1375 fathoms. + + +5. _Semantis distephanus_, n. sp. (Pl. 83, fig. 3). + +Sagittal ring thin, semicircular, smaller than the thin basal ring, which +exhibits two semicircular gates. Both rings are armed with numerous small +spines of equal size, which on the former are arranged in two, on the +latter in three regular rows. (The basal rod of the sagittal ring, +separating the two basal gates, in fig. 3 is, by mistake, not distinctly +enough drawn.) + +_Dimensions._--Height of the sagittal ring 0.06, breadth 0.08. + +_Habitat._--Tropical Atlantic, Station 348, surface. + + +{958}6. _Semantis spinescens_, Haeckel. + + _Stephanolithis spinescens_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. + Wiss. Berlin, p.160, Taf. i. fig. 29. + + _Stephanolithis spinescens_, Buetschli, 1882, Zeitschr. f. wiss. Zool., + vol. xxxvi. p. 497, Taf. xxxii. figs. 7_a_, 7_b_. + +Sagittal ring ovate with four pairs of thin, irregularly branched spines, +two apical pairs, one on the straight dorsal rod and one on the curved +ventral rod. Basilar rod with a posterior and an anterior forked rod +(commencing caudal and sternal foot). Basal ring square, with two lateral +spines, and two triangular gates scarcely one-third as broad as the +ring-gate. An internal ascending procolumna (rod _c__1 in the figure of +Buetschli) connects the basal and ventral rods of the sagittal ring. + +_Dimensions._--Height of the sagittal ring 0.1, breadth 0.07. + +_Habitat._--Fossil in Barbados. + + + +Genus 408. _Semantrum_,[27] n. gen. + +_Definition._--#Semantida# with four basal pores (two anterior jugular and +two posterior cardinal pores), without typical basal feet. + +The genus _Semantrum_, one of the most important of the NASSELLARIA, arises +from the preceding _Semantis_ by duplication of the two basal gates. Behind +the pair of coracal rods there arises from the basilar rod of the sagittal +ring a third pair of lateral horizontal branches, the scapular rods. These +become connected with the coracal rods on each side, and so produce a +second posterior pair of basal pores, the "cardinal gates." These are +constantly larger than the anterior "jugular gates." Therefore the vertical +ring of _Semantrum_ possesses a horizontal basal ring with four very +characteristic gates, enclosed by three pairs of lateral curved and +connected branches, and these become transmitted by heredity to the +majority of the NASSELLARIA. + + +1. _Semantrum quadrifore_, n. sp. (Pl. 92, fig. 5). + +Sagittal ring subcircular or ovate, with three edges and four sagittal +forked spines on the odd edge (two dorsal and two ventral spines). Basal +ring decagonal, with ten simple or forked spines on the ten corners. +Jugular gates tetragonal. Cardinal gates pentagonal. + +_Dimensions._--Height of the sagittal ring 0.09, breadth 0.07. + +_Habitat._--Tropical Atlantic, Station 351, surface. + + +{959}2. _Semantrum tetrastoma_, n. sp. (Pl. 92, fig. 3). + +Sagittal ring semicircular, thorny, without edges. Basal ring tetragonal or +nearly cordate, with a small anterior and a large posterior bow-shaped +incision; on the lateral edges with numerous irregular thorns. Jugular +gates pear-shaped. Cardinal gates nearly kidney-shaped. + +_Dimensions._--Height of the sagittal ring 0.1 to 0.14, breadth 0.07 to +0.09. + +_Habitat._--Central Pacific, Stations 265 to 268, depth 2700 to 2900 +fathoms. + + +3. _Semantrum tetrapylum_, n. sp. + +Sagittal ring elliptical, tuberculate. Basal ring trapezoidal, also with +roundish thick rods and small irregular tubercles on the margin. Jugular +gates ovate, two-thirds as broad as the triangular cardinal gates. + +_Dimensions._--Height of the sagittal ring 0.08, breadth 0.05. + +_Habitat._--North Pacific, Station 253, depth 3125 fathoms. + + +4. _Semantrum muelleri_, Haeckel. + + _Stephanolithis muelleri_, Buetschli, 1882, Zeitschr. f. wiss. Zool., + vol. xxxvi pp. 499, 539, Taf. xxxii. figs. 8_a_, 8_b_, 8_c_. + +Sagittal ring nearly semicircular or obliquely ovate, thorny. Basal ring +also nearly semicircular, with two slight sagittal incisions (one anterior +and one posterior), on the lateral edges with numerous small thorns. +Jugular pores (pair I of Buetschli) pear-shaped. Cardinal pores (pair II of +Buetschli) triangular. Sometimes (but not constantly) a pair of cervical +bows connects the scapular bars with the subvertical dorsal rod of the +sagittal ring. + +_Dimensions._--Height of the sagittal ring 0.09, breadth 0.06. + +_Habitat._--Fossil in Barbados. + + +5. _Semantrum sphragisma_, n. sp. + +Sagittal ring circular, smooth. Basal ring also nearly circular and smooth; +its four basal gates of nearly equal size, elliptical or subcircular; the +jugular pores scarcely smaller than the cardinal pores. All rods smooth, +cylindrical, without edges and thorns. + +_Dimensions._--Height of the sagittal ring 0.08, breadth 0.07. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms; also fossil +in Barbados. + + +6. _Semantrum buetschlii_, n. sp. + +Sagittal ring triangular, with vertical straight ascending dorsal rod, +horizontal straight basilar rod and obliquely ascending, slightly curved +ventral rod; all rods nearly cylindrical, with irregular {960}branched +thorns and distorted edges. Jugular pores triangular, scarcely half as +broad as the large semicircular cardinal pores. + +_Dimensions._--Height of the sagittal ring 0.11, breadth 0.08. + +_Habitat._--Fossil in Barbados. + + +7. _Semantrum signarium_, n. sp. (Pl. 92, fig. 4). + +Sagittal ring obliquely ovate, thorny. Basal ring kidney-shaped or nearly +pentagonal, with broad concave dorsal incision and five larger branched +spines on the five corners; between them smaller thorns. Jugular gates +pear-shaped, scarcely half as broad as the triangular cardinal gates. + +_Dimensions._--Height of the sagittal ring 0.12, breadth 0.09. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +Genus 409. _Semantidium_,[28] n. gen. + +_Definition._--#Semantida# with six basal pores (two anterior jugular, two +middle cardinal, and two posterior cervical pores), without typical basal +feet. + +The genus _Semantidium_ exhibits a further developmental stage of the basal +plate of the Semantida. Whilst this plate in _Semantis_ possesses one pair +of basal pores, and in _Semantrum_ two pairs, here in _Semantidium_ it has +three pairs. The new third pair is produced on the dorsal edge of the basal +plate, which becomes connected with the basal part of the dorsal rod of the +sagittal ring by a pair of cervical rods. The middle pair of pores (the +cardinal) are always larger than the anterior (jugular) and the posterior +(cervical pores). The same form of basal plate is preserved in numerous +#Spyroidea# and #Cyrtoidea#, as a "cortinar septum with six collar pores," +(_e.g._, Pl. 53, fig. 18). + + +1. _Semantidium hexastoma_, n. sp. (Pl. 92, fig. 6). + +Sagittal ring ovate, thorny. Basal ring rhombic or nearly square, with four +short conical descending spines on the four prominent edges (two sagittal +and two lateral); between them numerous smaller irregular thorns. Jugular +and cervical gates nearly equal, ovate, half as broad as the triangular +cardinal gates between them. + +_Dimensions._--Height of the sagittal ring 0.14, breadth 0.1. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +2. _Semantidium sexangulum_, n. sp. + +Sagittal ring ovate, with six pairs of short branched thorns (two apical, +two dorsal, and two ventral). Basal ring hexagonal, with three pairs of +short branched thorns on the six corners (one {961}sagittal pair, one +posterior and one anterior). All six gates of the basal plate triangular, +the jugular and cervical a little smaller than the cardinal gates. + +_Dimensions._--Height of the sagittal ring 0.1, breadth 0.07. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms. + + +3. _Semantidium haeckelii_, Buetschli. + + Stephanolithis Haeckelii, Buetschli, 1882, Zeitschr. f. wiss. Zool., vol. + xxxvi. pp. 499, 538, Taf. xxxii. figs. 6_a_, 6_b_. + +Sagittal ring elliptical, with three pairs of short horizontal branched +spines, one apical and two equatorial pairs (one dorsal and one ventral). +Basal ring roundish hexagonal, with numerous short thorns on the margin. +Jugular pores ovate, about half as broad as the ovate cardinal pores and +twice as broad as the small cervical pores. + +_Dimensions._--Height of the sagittal ring 0.08, breadth 0.06. + +_Habitat._--Fossil in Barbados. + + +4. _Semantidium signatorium_, n. sp. (Pl. 92, fig. 7). + +Sagittal ring semicircular, thorny; basal ring pentagonal, with short +spines on the margin and five stronger thorny spines on the five corners. +Jugular pores ovate, smaller than the triangular cervical pores. Cardinal +pores two to three times as large as each of the former, pentagonal. + +_Dimensions._--Height of the sagittal ring 0.08, breadth 0.12. + +_Habitat._--North Pacific, Station 341, depth 2300 fathoms. + + + +Genus 410. _Clathrocircus_,[29] Haeckel, 1881, Prodromus, p. 447. + +_Definition._--#Semantida# with a variable number of pores on the apical +and the basal part of the ring, symmetrically arranged, without typical +basal feet. + +The genus _Clathrocircus_ comprises those Semantida in which the sagittal +ring bears not only basal pores (as in the three preceding genera) but also +apical pores (on the opposite pole of the main axis), or a variable number +of pores along the whole ring. All these pores are symmetrically arranged +in pairs. In the simplest form there are only two apical pores opposite to +four basal pores, whilst in the highest state of development the whole ring +bears two complete circles of pores. At both poles of the transverse axis +two large lateral gates remain open. If these become closed by +lattice-work, _Clathrocircus_ passes over into _Dictyospyris_. + + +{962}1. _Clathrocircus hexaporus_, n. sp. + +Sagittal ring circular, smooth, with three pairs of pores (one apical and +two basal). The two apical pores are triangular with two lateral spines, +and correspond to the two mitral gates of the Tympanida. The four basal +pores form a hexagonal basal plate, with six lateral spines, and correspond +to the four basal pores of _Semantrum_; the two jugular are pear-shaped, +and half as broad as the two triangular cardinal pores. + +_Dimensions._--Height of the sagittal ring 0.08, breadth 0.06. + +_Habitat._--Cosmopolitan; Atlantic, Pacific, many Stations, surface. + + +2. _Clathrocircus octoporus_, n. sp. + +Sagittal ring elliptical, smooth, with four pairs of pores (two apical and +two basal). The four apical pores are of nearly equal size, subcircular, +and form a regular cross around the apical pole. The four basal pores are +ovate, and form a quadrangular plate, armed with marginal thorns; the two +jugular pores are somewhat smaller than the two cardinal pores. + +_Dimensions._--Height of the sagittal ring 0.11, breadth 0.08. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms. + + +3. _Clathrocircus decaporus_, n. sp. + +Sagittal ring ovate, thorny, with five pairs of pores (two apical and three +basal). The four apical pores are roundish and form a cross. The six basal +pores are triangular and form a hexagonal plate with thorny margin; the two +jugular pores are somewhat larger than the two cervical, and half as broad +as the two cardinal pores. + +_Dimensions._--Height of the sagittal ring 0.09, breadth 0.07. + +_Habitat._--North Pacific, Station 256, depth 2950 fathoms. + + +4. _Clathrocircus stapedius_, n. sp. (Pl. 92, fig. 8). + +Sagittal ring ovate, smooth, with six pairs of pores (two apical and four +basal). The four apical pores are of nearly equal size and form a +quadrangular mitral plate with two large lateral horns. The eight basal +pores are of very different size (the four central far larger than the two +anterior and the two posterior), and form a hexagonal basal plate, also +with two large lateral horns. The four branched lateral horns (two upper +and two lower) form together an incomplete frontal ring. + +_Dimensions._--Height of the sagittal ring 0.1, breadth 0.08. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +{963}5. _Clathrocircus dictyospyris_, n. sp. (Pl. 92, fig. 9). + +Sagittal ring ovate, thorny, with eight pairs of pores. The four apical and +the four basal pores are elliptical and far larger than the four dorsal and +the four ventral pores. Resembles a _Dictyospyris_ with open lateral gates. + +_Dimensions._--Height of the sagittal ring 0.08, breadth 0.06. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +6. _Clathrocircus multiforis_, n. sp. (Pl. 92, fig. 10). + +Sagittal ring circular, smooth, with ten to twelve pairs of roundish pores, +forming together a complete lattice-girdle with two parallel circular rows +of pores. Four larger of these are the four gates of the basal ring (two +jugular and two cardinal pores). + +_Dimensions._--Diameter of the ring 0.1 to 0.15, breadth 0.03 to 0.05. + +_Habitat._--Central Pacific, Stations 263 to 274, depth 2350 to 2925 +fathoms. + + + +Subfamily 2. CORTINISCIDA, Haeckel. + +_Definition._--#Semantida# with large, typical, regularly disposed basal +feet (originally three cortinar feet, one odd caudal and two paired +pectoral). + + + +Genus 411. _Cortiniscus_,[30] n. gen. + +_Definition._--#Semantida# with three typical basal feet (an odd caudal +foot and two paired lateral or pectoral feet). + +The genus _Cortiniscus_ is of peculiar importance, as the common ancestral +form of the _Cortiniscida_, or those Semantida in which the basal ring is +provided with typical, regularly disposed basal feet--three, four, or six. +Since these typical basal feet (or "cortinar feet") are preserved in the +greater number of all NASSELLARIA, determining their triradial structure, +they possess a great morphological value. _Cortiniscus_ exhibits the same +three primary feet as _Cortina_, from which it differs in the production of +two or more basal pores (between the odd caudal and the paired lateral +feet). + + +1. _Cortiniscus tripodiscus_, n. sp. (Pl. 92, fig. 11). + +Sagittal ring ovate, thorny, with three prominent, distorted edges; its +dorsal rod nearly straight and vertical, with one or two pairs of short +thorns; its ventral rod strongly curved, with three or four pairs of +divergent thorns. Basal ring larger than the sagittal ring, with two +semicircular gates and obliquely ascending halves, which on the inner and +lower edge are smooth, {964}on the outer and upper thorny. Apical horn and +the three divergent feet nearly equal, straight, about as long as the +sagittal ring, with three thorny edges. + +_Dimensions._--Height of the sagittal ring 0.1 to 0.12, breadth 0.07 to +0.09. + +_Habitat._--Central Pacific, Stations 270 to 274, depth 2350 to 2925 +fathoms. + + +2. _Cortiniscus dipylaris_, n. sp. (Pl. 92, fig. 13). + +Sagittal ring nearly semicircular, with prominent distorted edges and six +pairs of small roundish papillate tubercles (three pairs on the straight +dorsal, three on the curved ventral rod). Apical horn short and stout, with +a tuberculate knob. Basal ring smaller than the sagittal ring with two +elliptical gates. Three feet short and stout, irregularly branched like a +cauliflower, with numerous short papillate tubercles. + +_Dimensions._--Height of the sagittal ring 0.11, breadth 0.08. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +3. _Cortiniscus tripylaris_, n. sp. + +Sagittal ring elliptical, smooth. Apical horn conical, smooth. Basal ring +larger than the sagittal ring, with three elliptical gates of equal size; +two paired, posterior (jugular pores) between the basal parts of the caudal +foot and the two pectoral feet, and an odd, anterior (sternal pore) between +the basal parts of the two pectoral feet and a connecting horizontal convex +sternal bow. + +_Dimensions._--Height of the sagittal ring 0.09, breadth 0.06. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms. + + +4. _Cortiniscus tetrapylaris_, n. sp. + +Sagittal ring elliptical, with four pairs of short branched thorns, two +posterior on the straight dorsal, and two anterior on the curved ventral +rod. Basal ring smaller than the sagittal ring, with four triangular gates; +the two anterior (jugular pores) a little smaller than the two posterior +(cardinal pores). Apical horn and the three divergent feet shorter than the +sagittal ring, irregularly branched, with curved, often tuberculate +branches. + +_Dimensions._--Height of the sagittal ring 0.08 to 0.12, breadth 0.06 to +0.1. + +_Habitat._--Fossil in Barbados. + + +5. _Cortiniscus typicus_, n. sp. (Pl. 92, fig. 12). + +Sagittal ring ovate, thorny, with three distorted edges; dorsal rod nearly +straight and vertical prolonged upwards into a stout thorny apical horn, +downwards into the caudal foot. Basal ring smaller than the sagittal ring, +with four elliptical or nearly triangular gates; the two anterior (jugular +pores) about half as large as the two posterior (cardinal pores). Three +feet of equal size, thorny, divergent, straight or slightly curved, about +as long as the diameter of the sagittal ring. + +_Dimensions._--Height of the sagittal ring 0.14 to 0.18, breadth 0.1 to +0.12. + +_Habitat._--Cosmopolitan; Atlantic, Indian, Pacific, at various depths. + + + +{965}Genus 412. _Stephaniscus_,[31] n. gen. + +_Definition._--#Semantida# with four typical basal feet (two sagittal and +two lateral or pectoral feet). + +The genus _Stephaniscus_ differs from the preceding _Cortiniscus_ in the +production of a fourth (sternal) foot, and therefore exhibits the same +relation to it that _Stephanium_ among the Stephanida bears to _Cortina_. +It differs from _Stephanium_, in the production of a basal ring, with pores +or gates between the bases of the basal feet. Two of these feet are +sagittal (the posterior caudal and the anterior sternal foot), whilst the +other two are lateral or pectoral (right and left). The basal lattice-plate +exhibits either two pores ("jugular gates") or four pores (two anterior +jugular and two posterior cardinal gates). + + +1. _Stephaniscus tetrapodius_, n. sp. + +Sagittal ring nearly circular, smooth, with a short conical apical horn. +Basal ring square, smooth, with two triangular gates. Four feet simple, +equal, conical, divergent, about as long as the diameter of the ring. + +_Dimensions._--Height of the sagittal ring 0.08, breadth 0.07. + +_Habitat._--Central Pacific, Stations 270 to 274, depth 2350 to 2925 +fathoms. + + +2. _Stephaniscus quadrifurcus_, n. sp. (Pl. 92, fig. 14). + +Sagittal ring subcircular, thorny with a small thorny apical horn. Basal +ring also nearly circular, with two large semicircular gates and a few +small thorns. All four feet curved and forked, the fork-branches again +ramified, with numerous short curved and pointed branches. The two lateral +feet (right and left) are larger and more branched than the two sagittal +feet (sternal and caudal foot). + +_Dimensions._--Height of the sagittal ring 0.12, breadth 0.1. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +3. _Stephaniscus quadrigatus_, n. sp. (Pl. 92, fig. 15). + +Sagittal ring oblique, ovate, with three prominent thorny edges; its dorsal +rod nearly straight and vertical, the ventral rod strongly curved; apex +with a small curved horn. Basal ring with a few short thorns and four gates +of different size; the two anterior (jugular pores) ovate or nearly +triangular, two-thirds as broad as the two posterior subcircular or +pentagonal (cardinal pores). All {966}four feet simple, curved, with three +edges, the posterior (caudal) foot larger, the anterior (sternal) foot +smaller than the two lateral (pectoral) feet. + +_Dimensions._--Height of the sagittal ring 0.09, breadth 0.07. + +_Habitat._--Tropical Atlantic, Station 351, surface. + + +4. _Stephaniscus medusinus_, n. sp. + +Sagittal ring elliptical, thorny, with a larger apical horn. Basal ring +nearly square, with short marginal thorns and four large ovate gates of +nearly equal size. All four feet of equal size divergent, curved, +irregularly branched, with short curved branches. + +_Dimensions._--Height of the sagittal ring 0.13, breadth 0.09. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. Fossil in +Barbados. + + + +Genus 413. _Semantiscus_,[32] n. gen. + +_Definition._--#Semantida# with six typical basal feet (two sagittal, two +pectoral, and two tergal feet). + +The genus _Semantiscus_ may be the archetype of those NASSELLARIA which +exhibit six typical basal feet, in combination with the sagittal ring. +Three of these are the primary feet of _Cortina_ and _Cortiniscus_, the +other three are secondary productions between the former. The basal ring +may possess either two, four, or six basal pores. + + +1. _Semantiscus hexapodius_, n. sp. (Pl. 92, fig. 16). + +Sagittal ring elliptical, with a large branched apical horn. Basal ring +small, square, with two small triangular gates (or jugular pores). From its +periphery there arise six short and stout cylindrical feet, one very large +(caudal) from the posterior corner, two tergal on each side, two opposite +(pectoral) from the lateral corners, and one odd sternal from the anterior +corner. All six spines bear a bunch of ten to twenty stout pointed conical +branches, partly simple, partly forked. + +_Dimensions._--Height of the sagittal ring 0.12, breadth 0.08. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +2. _Semantiscus hexaspyris_, n. sp. (Pl. 92, fig. 18). + +Sagittal ring semicircular, broad, latticed, with two pairs of irregular +dorsal and two pairs of ventral pores. The dorsal rod is straight and +vertical, prolonged upwards into a short serrate apical horn, downwards +into a straight linear caudal foot. The ventral rod is curved and prolonged +into a similar sternal foot. Basal ring hexagonal, with four ovate gates +(two smaller jugular and two larger cardinal pores); its four lateral +corners prolonged into four curved thorny lateral feet (two {967}anterior +larger pectoral, and two posterior smaller tergal feet). This species may +be regarded as a commencing _Hexaspyris_ or _Liriospyris_. + +_Dimensions._--Height of the sagittal ring 0.08, breadth 0.06. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +3. _Semantiscus hexapylus_, n. sp. (Pl. 92, fig. 17). + +Sagittal ring ovate, thorny, with a small apical horn. Basal ring with six +roundish or nearly triangular gates; the two jugular pores are smaller than +the two cardinal and larger than the two cervical pores. The separating +bars between these six pores are prolonged into six straight, thorny widely +divergent feet; three larger feet (the caudal and the two pectoral) with a +pair of apophyses, three smaller between them simple (the sternal and the +two tergal feet). + +_Dimensions._--Height of the sagittal ring 0.13, breadth 0.09. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + + +Family #L. CORONIDA#, Haeckel. + + _Triostephida_, Haeckel, 1881, Prodromus, p. 445. + +_Definition._--STEPHOIDEA with two crossed vertical rings, perpendicular +one to the other (the primary sagittal and the secondary frontal ring). +Usually their common base bears a horizontal basal ring, but a mitral ring +(or a horizontal ring at the apex) is never developed. + +The family #Coronida# comprises those #Stephoidea# in which the primary +sagittal ring (of the Stephanida and Semantida) becomes crossed by a second +vertical ring, the lateral or frontal ring. Between these two vertical +meridian rings, perpendicular to one another, four large apertures remain +constantly open, the "lateral" gates. But besides these four constant +openings, usually (excepting only in the Zygostephanida) other gates are +developed on the common base of the two crossed rings, produced by a third, +horizontal, basal ring. These basal gates are the same which we have found +already in the Semantida. + +The distinction of the Coronida from the other #Stephoidea# is always easy. +In the Stephanida and Semantida, the frontal ring, or the second meridian +ring, which we find in all Coronida, is never developed. On the other hand +these latter never exhibit the typical "mitral ring," or the second, upper, +horizontal ring, which distinguishes the Tympanida. + +We distinguish here, among the Coronida, four different subfamilies, which +perhaps afterwards may be better separated as families. Of these four +groups the Zygostephanida and Acanthodesmida exhibit the nearest +relationship to the Stephanida, whilst the Eucoronida and Trissocyclida +possess a closer affinity with the Semantida. + +{968}The Zygostephanida, constituting the first subfamily, exhibit four +large gates only, and differ from all other Coronida in the absence of a +basal ring and of basal gates. Therefore the skeleton is entirely composed +of two crossed vertical rings, perpendicular to one another; the first is +the primary or sagittal ring (inherited from the Stephanida), the second is +the new lateral or frontal ring. The four large lateral gates are either +quite simple (_Zygostephanus_) or partly closed by loose and irregular +lattice-work (_Zygostephanium_). The Zygostephanida may be derived directly +from the Stephanida by development of lateral branches forming a frontal +ring. They commonly possess the same characteristic spines or branches, and +the same typical difference between the straight dorsal rod and convex +ventral rod of the sagittal ring, which we found in the greater number of +Stephanida. The frontal ring is commonly elliptical or kidney-shaped, and +much larger than the ovate sagittal ring. + +The Acanthodesmida, forming the second subfamily of Coronida, differ from +all other members of this family in the possession of a large simple basal +gate, surrounded by a simple horizontal basal ring. Only this ring is +complete, whilst the two crossed vertical meridian rings (the primary +sagittal and the secondary frontal ring) are incomplete, both truncated at +the base by the basal ring. Therefore there remain here between the three +rings five large gates (recognised previously by Johannes Mueller in 1856 +in _Acanthodesmia_): four lateral gates (the same as in the Zygostephanida) +and one central basal gate. The latter is always quite simple and serves +for the emission of the pseudopodia, arising from the basal pole of the +central capsule. The four lateral gates are either quite simple +(_Coronidium_) or partly closed by irregular loose lattice-work +(_Acanthodesmia_). The subfamily Acanthodesmida may be derived either +directly from the Stephanida (by development of a central basal gate) or +from the Eucoronida (by loss of the basilar part of the sagittal ring). + +The Eucoronida, the third subfamily, are the most important group of the +Coronida; their numerous species are much more frequent and more widely +distributed than those of the other three subfamilies. They may be derived +immediately from the Semantida by the development of a lateral or frontal +ring. This remains incomplete in the basal part, whilst the two other +rings, perpendicular to it (the vertical sagittal ring and the horizontal +basal ring), are complete. Therefore the shell constantly exhibits six +large open gates between the three rings; four lateral gates (the same as +in the Zygostephanida and Acanthodesmida) and two basal gates (inherited +from _Semantis_); the latter correspond to the "jugular pores" of the +#Spyroidea# and #Cyrtoidea#; they remain constantly simple. The four +lateral gates may also remain simple (_Eucoronis_) or they may become +partly closed by irregular loose lattice-work (_Plectocoronis_). The +remarkable genus _Podocoronis_ is distinguished by the development of +typical descending basal feet, which are regularly disposed and correspond +to the typical "cortinar feet" of the other NASSELLARIA. There may be +developed either two lateral feet (as lower {969}prolongations of the +segments of the frontal ring), or three feet (one caudal and two pectoral, +as in _Cortina_ and _Cortiniscus_), or four feet (two sagittal and two +lateral, as in _Stephanium_ and _Stephaniscus_), or six feet (two sagittal, +two pectoral, two tergal, as in _Semantiscus_), sometimes numerous feet (as +in _Petalospyris_ and _Anthocyrtis_, &c.). + +The Trissocyclida represent the fourth and last subfamily of Coronida, +distinguished from all others in the possession of three complete rings, +perpendicular one to another, and of eight large gates separated by them. +Two of the three rings are vertical (the primary sagittal and the secondary +frontal ring), the third is horizontal (the basal ring). The four upper +gates correspond to the four lateral gates of the preceding three +subfamilies; the four lower gates are the same as the four basal gates of +_Semantrum_ (two primary jugular and two secondary cardinal gates); +therefore the Trissocyclida may be derived directly from these Semantida by +development of a complete frontal ring. Probably the two jugular gates were +originally smaller than the two cardinal, but usually they have become +equal. In _Tristephanium_ (the common ancestral form of the Trissocyclida) +and in the closely allied _Tricyclidium_ the four basal gates remain +smaller than the four lateral gates. But in two other genera, +_Trissocircus_ and _Trissocyclus_, the four lower or basal gates reach the +same size as the four upper or lateral gates; therefore all eight gates +become equal and the basal ring becomes equatorial. In the most regular +species of the latter genera also the three rings become perfectly equal +and cannot be any longer distinguished. Here the original bilateral (or +dipleuric) fundamental form of the shell passes over into a regular cubic +or octahedral form (with three equal, isopolar axes, perpendicular one to +another). The eight large gates of the Trissocyclida usually remain simple +(_Tristephanium_, _Trissocircus_), but sometimes they become partly closed +by loose lattice-work (_Tricyclidium_, _Trissocyclus_). + +The original rings, and the secondary rods or bars, composing the loose +framework of the Coronida are either roundish (with circular or elliptical +transverse section) or three-edged (with triangular transverse section), +rarely quadrangular or provided with distorted edges. The branches or +spines arising from them, are either simple or branched, and offer a great +variety in number, form, and disposition. The most important forms are +those which develop the three typical basal feet of _Cortina_, _e.g._, +_Podocoronis cortina_ (Pl. 97, fig. 2). + +The _Central Capsule_ of the Coronida is the same as in the other +#Stephoidea# (comp. p. 937), and offers all those characteristic +peculiarities of "Monopylea" which we have mentioned above in the general +description of the NASSELLARIA (p. 890). Usually it is spherical or +ellipsoidal, often violin-shaped or bilobed, with a sagittal constriction. +The porochora of its basal pole is in close contact with the base of the +sagittal ring. + +{970}_Synopsis of the Genera of Coronida._ + + ------------------------------------------------------------------------- + I. Subfamily Zygostephanida. Four lateral gates (no basal gate). + ------------------------------------------------------------------------- + Two meridional rings }Four lateral gates + (sagittal and frontal) } simple, 414. _Zygostephanus_. + complete, perpendicular } + to one }Four lateral gates + another (no basal } partly latticed, 415. _Zygostephanium_. + ring). + ------------------------------------------------------------------------- + II. Subfamily Acanthodesmida. + Five large gates (four lateral and one simple basal). + ------------------------------------------------------------------------- + Two meridional rings }Four lateral gates + (sagittal and frontal) } simple, 416. _Coronidium_. + incomplete, both } + truncated by the }Four lateral gates + complete horizontal } partly latticed, 417. _Acanthodesmia_. + basal ring. + ------------------------------------------------------------------------- + III. Subfamily Eucoronida. Six large gates (four lateral and two basal). + ------------------------------------------------------------------------- + Two rings (the {Basal ring {Gates simple, 418. _Eucoronis_. + sagittal meridional{ without larger{ + ring and the { descending {Gates partly + horizontal basal { feet. { latticed, 419. _Plectocoronis_. + ring) complete, the{ + frontal meridian {Basal ring with large, + ring incomplete. { regularly disposed, + { descending feet. Gates + { simple, 420. _Podocoronis_. + ------------------------------------------------------------------------- + IV. Subfamily Trissocyclida. + Eight large gates (four upper lateral and four lower basal). + ------------------------------------------------------------------------- + Two meridional {Four upper {Gates simple, 421. _Tristephanium_. + rings (sagittal and{ gates larger { + frontal) and the { than the {Gates partly + horizontal basal { four lower. { latticed, 422. _Tricyclidium_. + ring complete. All { + three complete {All eight gates{Gates simple, 423. _Trissocircus_. + rings perpendicular{ of equal size.{ + to one another. { {Gates partly + {latticed, 424. _Trissocyclus_. + + + +Subfamily 1. ZYGOSTEPHANIDA, Haeckel, 1881, Prodromus, p. 446. + +_Definition._--#Coronida# with four large lateral gates, without basal +gate. Skeleton composed of two complete vertical rings, perpendicular one +to another--the primary sagittal and the secondary frontal ring. + + + +Genus 414. _Zygostephanus_,[33] Haeckel, 1862, Monogr. d. Radiol., p. 268. + +_Definition._--#Coronida# with four large, simple, lateral gates, without +basal gate and lattice-work. Skeleton composed of two simple meridional +rings, perpendicular to one another. + +The genus _Zygostephanus_, founded by me in 1862 for the Mediterranean +_Zygostephanus muelleri_, is the simplest and most primitive of all the +Coronida, and may {971}therefore be regarded as the common ancestral form +of this family. The simple skeleton is composed of two meridional rings +only, perpendicular one to another--a sagittal and a frontal ring. + + + +Subgenus 1. _Zygostephus_, Haeckel, 1881, Prodromus, p. 446. + +_Definition._--The two vertical rings of nearly equal height, therefore +without sagittal constriction. + + +1. _Zygostephanus dissocircus_, n. sp. (Pl. 93, fig. 1). + +Both rings elliptical, of nearly equal height, smooth, without spines. +Frontal ring somewhat longer than the sagittal. No sagittal constriction. + +_Dimensions._--Height of the rings 0.07, breadth 0.1. + +_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Pacific, surface. + + +2. _Zygostephanus serratus_, n. sp. + +Both rings elliptical, of nearly equal height, with a serrate prominent +edge on the outer convexity (in the transverse section three-edged). No +sagittal constriction. + +_Dimensions._--Height of the rings 0.08, breadth 0.12. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +3. _Zygostephanus muelleri_, Haeckel. + + _Zygostephanus muelleri_, Haeckel, 1862, Monogr. d. Radiol., p. 268, Taf. + xii. fig. 2. + +Both rings elliptical, of nearly equal height, armed with numerous (about +fifty) slender curved spines, as long as the radius of the rings; commonly +each ring with twelve pairs of divergent spines. No sagittal constriction. + +_Dimensions._--Height of the rings 0.06, breadth 0.1. + +_Habitat._--Mediterranean (Messina), surface. + + +4. _Zygostephanus ramosus_, n. sp. + +Both rings elliptical, of nearly equal height, armed with numerous branched +spines, which are arranged on each ring in two divergent rows; the branches +of the spines are curved and partly protect the open gates. No sagittal +constriction. + +_Dimensions._--Height of the rings 0.07, breadth 0.09. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + + +{972}Subgenus 2. _Zygostephaniscus_, Haeckel, 1881, Prodromus, p. 446. + +_Definition._--The two vertical rings of different heights; the frontal +ring higher than the sagittal ring, therefore with a sagittal constriction +in the median plane. + + +5. _Zygostephanus reniformis_, n. sp. + +Frontal ring kidney-shaped, in the upper half convex, in the lower concave, +in the latter with a deep sagittal constriction, armed with numerous +irregular short spines. Sagittal ring thicker and lower, only two-thirds as +high, with four pairs of short divergent spines (two ventral and two dorsal +pairs). + +_Dimensions._--Height of the frontal ring 0.13, breadth 0.2. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +6. _Zygostephanus violina_, n. sp. + +Frontal ring violin-shaped, on the upper and the lower margin concave, with +a deep sagittal constriction, armed with numerous irregular spines, which +are partly simple, partly branched. Sagittal ring thicker and lower, only +half as high, with a few short conical spines at the apical and basal +poles. + +_Dimensions._--Height of the frontal ring 0.12, breadth 0.18. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +7. _Zygostephanus bicornis_, n. sp. (Pl. 93, fig. 2). + +Frontal ring violin-shaped, on the upper and the lower margin concave, with +a deep sagittal constriction; its two halves pentagonal. Between numerous +smaller spines there arise from the frontal ring six groups of larger +branched spines, two odd in the corners of the highest points (curved like +two horns), two branched pairs on the prominent lateral corners (at right +and left), and two pairs in the corners of the lowest points (like four +branched basal feet). Sagittal ring only two-thirds as high, with four +pairs of irregular spines. + +_Dimensions._--Height of the frontal ring 0.11, breadth 0.16. + +_Habitat._--South Pacific Station 300, depth 1375 fathoms. + + + +Genus 415. _Zygostephanium_,[34] Haeckel, 1881, Prodromus, p. 446. + +_Definition._--#Coronida# with four large, partly latticed, lateral gates, +without basal gate. Skeleton composed of two meridional rings perpendicular +to each other. + +The genus _Zygostephanium_ differs from the preceding ancestral genus +_Zygostephanus_ in the development of lattice-work along the two crossed +rings, produced by their anastomosing branches. Therefore the four large +lateral gates between them, which are quite simple, in the preceding genus +here become more or less fenestrated. + + +{973}1. _Zygostephanium dizonium_, n. sp. (Pl. 93, fig. 3). + + _Tympaniscus dizonius_, Haeckel, 1882, Manuscript. + +Both rings elliptical, of nearly equal height, smooth, without spines. +Sagittal ring with four pairs of small pores (two apical pairs and two +basal pairs). Frontal ring with three pairs of small pores (one pair +lateral, one pair above and one pair below). + +_Dimensions._--Height of the frontal ring 0.08, breadth 0.12. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +2. _Zygostephanium paradictyum_, n. sp. (Pl. 93, fig. 4). + +Frontal ring kidney-shaped, in the upper half convex, in the lower concave, +in the latter with a deep sagittal constriction. Sagittal ring ovate, about +two-thirds as high as the frontal ring. Both rings three-edged, armed with +numerous short and branched bristle-shaped spines, which anastomose along +their three edges and produce two series of irregular polygonal pores. + +_Dimensions._--Height of the frontal ring 0.08, breadth 0.13. + +_Habitat._--North Pacific, Station 236, surface. + + +3. _Zygostephanium constrictum_, n. sp. + +Frontal ring violin-shaped, concave on the upper and lower margins, with a +deep sagittal constriction. Sagittal ring ovate, about two-thirds as high +as the frontal ring. Both rings covered with numerous branched irregular +spines, which partly anastomose along the edges of the rings, and produce +small irregular polygonal pores. + +_Dimensions._--Height of the frontal ring 0.12, breadth 0.18. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + + +Subfamily 2. ACANTHODESMIDA, Haeckel, 1881, Prodromus, p. 445. + +_Definition._--#Coronida# with five large gates (four lateral and one +basal). Skeleton composed of three rings, perpendicular one to another, two +of which are vertical and incomplete (the primary or lateral, and the +secondary or frontal), the third is horizontal and complete (the tertiary +or basal ring). + + + +Genus 416. _Coronidium_,[35] Haeckel, 1881, Prodromus, p. 445. + +_Definition._--#Coronida# with five large simple gates (four lateral and +one basal). Skeleton composed of two incomplete meridional rings and one +complete basal ring, without lattice-work. + +{974}The genus _Coronidium_ and the following, nearly allied +_Acanthodesmia_, form together the peculiar subfamily of +Acanthodesmida--not in the wider sense in which I first founded this group +(1862, Monogr. d. Radiol., p. 265), but in the restricted sense, which is +exactly defined in my Prodromus (1881, p. 445). According to this +definition, the shell is composed of three different rings, perpendicular +to one another; only one of these is complete, the simple horizontal basal +ring; the two others are incomplete and vertical (the primary or sagittal +and the secondary or frontal ring). Therefore there remain constantly +between the three rings five characteristic large openings or gates; four +of these are lateral (between the halves of the two meridional rings), the +fifth is basal, enclosed by the horizontal basal ring. The longest known +type of this subfamily is _Acanthodesmia vinculata_, the five +characteristic gates of which are clearly distinguished by its discoverer, +Johannes Mueller ("Das Gehaeuse besteht nur aus den Leisten zwischen fuenf +grossen Luecken"). The Acanthodesmida may be derived from the Eucoronida by +reduction of the basilar rod of the sagittal ring. If in _Eucoronis_ this +basal rod be lost, _Coronidium_ arises. + + +1. _Coronidium dyostephanus_, n. sp. (Pl. 82, fig. 7). + +Frontal ring elliptical, with few scattered thorns, twice as broad as high, +and three times as broad as the smooth rhombic basal ring. Sagittal ring +semicircular, very stout, twice as thick as the two other rings, with short +lateral thorns (in the figure seen from the apical pole, which exhibits a +four-lobed dimple). Basal gate rhombic. + +_Dimensions._--Height of the frontal ring 0.08, breadth 0.16. + +_Habitat._--Central Pacific, Station 263, depth 2650 fathoms. + + +2. _Coronidium diadema_, n. sp. (Pl. 82, fig. 8). + +Frontal ring kidney-shaped, one and a half times as broad as high, with a +slight sagittal constriction. Sagittal ring ovate, smaller, about of the +same size as the elliptical basal ring. Rods of all three rings +cylindrical, bearing numerous short and stout curved spines, partly simple, +partly branched. Four bunches of larger spines on the four corners of the +basal ring, and one very large bunch on the apical pole. Basal gate +elliptical, one and a half times as broad as long. + +_Dimensions._--Height of the frontal ring 0.13, breadth 0.18. + +_Habitat._--Indian Ocean (Madagascar), Rabbe, surface. + + +3. _Coronidium cervicorne_, n. sp. (Pl. 82, fig. 1). + +Frontal ring kidney-shaped, twice as broad as high, one and a half times as +broad as the elliptical basal ring, both with a slight sagittal +constriction. Sagittal ring ovate. All three rings {975}(in the figure seen +from the apical pole) with cylindrical rods, armed with numerous stout +spines, branched like a deer's antler. Basal gate rather oblong, twice as +broad as long. + +_Dimensions._--Height of the frontal ring 0.08, breadth 0.16. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +4. _Coronidium acacia_, n. sp. (Pl. 82, fig. 2). + +Frontal ring and sagittal ring nearly circular, of equal size, truncated at +the base. Basal ring circular, somewhat smaller. All three rings with +prominent edges, bearing bunches of short and straight pointed spines, like +those of an Acacia. Basal gate circular. + +_Dimensions._--Height of the frontal ring 0.12, breadth 0.14. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms. + + + +Genus 417. _Acanthodesmia_,[36] J. Mueller, 1856, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 485. + +_Definition._--#Coronida# with five large, partly latticed gates (four +lateral and one basal). Skeleton composed of two incomplete, partly +fenestrated meridional rings, and one complete basal ring. + +The genus _Acanthodesmia_, the oldest known form of all Coronida, differs +from the preceding _Coronidium_, its ancestral form, in the development of +irregular loose lattice-work along the rings, and therefore bears to it the +same relation that _Zygostephanium_ does to _Zygostephanus_. The first +species described by Johannes Mueller, _Acanthodesmia vinculata_ ("with +five large gates between the bars of the shell") remains the true type of +this genus; the second species described by him (_Acanthodesmia dumetum_) +belongs to the Plectanida (_Polyplecta_). + + +1. _Acanthodesmia vinculata_, J. Mueller. + + _Acanthodesmia vinculata_, J. Mueller, 1858, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 30, Taf. i. figs. 4-6 (_non_ 7). + + _Lithocircus vinculatus_, J. Mueller, 1856, Monatsber. d. k. preuss. + Akad. d. Wiss. Berlin, p. 484. + +Frontal ring violin-shaped, one and a half times as broad as high, with a +sagittal constriction. Sagittal ring ovate, smaller. The four gates between +the two rings are partly fenestrated by a few thin threads, irregularly +branched and connecting the two rings. A few short thorns are scattered +here and there. Basal gate elliptical. + +_Dimensions._--Height of the frontal ring 0.12, breadth 0.18. + +_Habitat._--Mediterranean (Nice), Atlantic (Canary Islands), surface. + + +{976}2. _Acanthodesmia ceratospyris_, n. sp. + +Frontal ring violin-shaped, one and a half times as broad as high, with a +deep sagittal constriction. Sagittal ring semicircular, half as high as the +frontal ring. The four gates between the two rings are partly fenestrated +by anastomosing branches of the numerous, irregularly branched spines, +which cover all three rings. Basal gate nearly circular, smaller than the +sagittal ring. + +_Dimensions._--Height of the frontal ring 0.08, breadth 0.12. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +3. _Acanthodesmia corona_, n. sp. (Pl. 93, fig. 5). + +Frontal ring kidney-shaped, nearly twice as broad as high, with a flat +sagittal constriction. Sagittal ring semicircular. The four gates between +the two rings are partly fenestrated by an arachnoidal network, composed of +thin, irregularly branched threads, arising from the rings. The edges of +all three rings are armed with irregular thorns. Basal gate circular, +larger than the sagittal ring. + +_Dimensions._--Height of the frontal ring 0.08, breadth 0.14. + +_Habitat._--Indian Ocean (Madagascar), Rabbe, surface. + + +4. _Acanthodesmia muelleri_, n. sp. + +Frontal ring kidney-shaped with a deep sagittal constriction. Sagittal ring +ovate. The four gates between the two rings irregularly fenestrated, with a +few large polygonal meshes. Edges of the rings with a few scattered thorns. +Basal gate violin-shaped. + +_Dimensions._--Height of the frontal ring 0.1, breadth 0.16. + +_Habitat._--Tropical Atlantic, Station 347, surface. + + + +Subfamily 3. EUCORONIDA, Haeckel, 1881, Prodromus, p. 445. + +_Definition._--#Coronida# with six large gates (four lateral and two basal +gates). Skeleton composed of three rings perpendicular to one another, two +of which are complete (the vertical sagittal, and the horizontal basal +ring); the third is incomplete (the vertical frontal ring). + + + +Genus 418. _Eucoronis_,[37] Haeckel, 1881, Prodromus, p. 445. + +_Definition._--#Coronida# with six large simple gates (four lateral and two +basal). Skeleton composed of two complete rings (the sagittal and basal) +and one incomplete (frontal) ring. Basal ring without typical feet. + +{977}The genus _Eucoronis_ and the following two nearly allied genera +(_Plectocoronis_ and _Podocoronis_) compose together the important +subfamily Eucoronida. In this typical main group of Coronida the shell is +constantly composed of three rings and six gates. The vertical sagittal +ring and the horizontal basal ring are complete (as in the Semantida); the +vertical frontal ring is incomplete. Between these three rings remain six +large open gates, the four upper (or lateral) are always much larger than +the four lower (or basal gates). _Eucoronis_ may be derived from _Semantis_ +by development of the frontal ring. + + + +Subgenus 1. _Acrocoronis_, Haeckel, 1881, Prodromus, p. 445. + +_Definition._--Rings smooth or rough, armed with numerous short spines or +thorns. + + +1. _Eucoronis perspicillum_, n. sp. (Pl. 82, fig. 6). + +Frontal ring elliptical, twice as broad as high, with a slight constriction +at the apical pole, armed with three pairs of short conical spines, one +apical pair (near the constriction) and two lateral pairs (one upper and +one lower pair). Sagittal ring of the same height, half the breadth and +double the thickness, also armed with three pairs of spines (one basal, one +dorsal, and one ventral pair). + +_Dimensions._--Height of the frontal ring 0.11, breadth 0.22. + +_Habitat._--Central Pacific, Stations 265 to 268, depth 2700 to 2900 +fathoms. + + +2. _Eucoronis laevigata_, n. sp. + +Frontal ring elliptical, smooth, one and a half times as broad as high, +without sagittal constriction, with horizontal basal gates. Sagittal ring +of the same height and thickness, also elliptical and smooth. No spines on +either of the smooth rings. + +_Dimensions._--Height of the frontal ring 0.1, breadth 0.15. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +3. _Eucoronis nephrospyris_, n. sp. (Pl. 82, fig. 5). + +Frontal ring kidney-shaped, in the upper half convex, in the lower concave, +with a sagittal constriction (often much deeper than in the specimen +figured). Sagittal ring ovate, about two-thirds as high as the frontal +ring. Rods of both rings without edges, cylindrical, armed with numerous +short conical thorns. + +_Dimensions._--Height of the frontal ring 0.1 to 0.12, breadth 0.15 to +0.18. + +_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Indian, Pacific, many +Stations, surface and at various depths. + + +{978}4. _Eucoronis angulata_, n. sp. (Pl. 82, fig. 3). + +Frontal ring violin-shaped, twice as broad as high, on the upper and the +lower margin concave, with a deep sagittal constriction. Sagittal ring +pentagonal, with straight horizontal basal rod, two-thirds as high as the +frontal ring. Rods of both rings with sharp prominent edges, bearing +numerous short pyramidal spines. + +_Dimensions._--Height of the frontal ring 0.09, breadth 0.17. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + + +Subgenus 2. _Lithocoronis_, Haeckel, 1881, Prodromus, p. 445. + +_Definition._--Rings armed with numerous large, branched or arborescent +spines. + + +5. _Eucoronis cervicornis_, n. sp. + +Frontal ring kidney-shaped, in the upper half convex, in the lower concave, +with sagittal constriction. Sagittal ring ovate, two-thirds as high as the +frontal ring. Both rings armed with numerous stout spines, irregularly +branched like a deer's antler. (Very similar to _Coronidium cervicorne_, +Pl. 82, fig. 1, which I formerly confounded with it, but differing in the +complete sagittal ring, which in the latter form is incomplete and has lost +its basal part.) + +_Dimensions._--Height of the frontal ring 0.12, breadth 0.2. + +_Habitat._--Central Pacific, Station 264, surface. + + +6. _Eucoronis arborescens_, n. sp. + +Frontal ring kidney-shaped, with a deep sagittal constriction in the +concave basal part. Sagittal ring ovate, half as high as the frontal ring. +Both rings armed with numerous thin, richly branched and arborescent spines +(branches much thinner and more numerous than in the preceding and +following species). + +_Dimensions._--Height of the frontal ring 0.15, breadth 0.25. + +_Habitat._--Equatorial Atlantic, Station 247, surface. + + +7. _Eucoronis challengeri_, n. sp. (Pl. 82, fig. 4). + + _Lithocoronis challengeri_, Haeckel, 1881, Prodromus, p. 445. + +Frontal ring violin-shaped, one and a half times as broad as high, with a +strong sagittal constriction. Sagittal ring nearly circular, two-thirds as +high as the frontal ring. Both rings armed with numerous irregularly +branched spines. (The specimen figured, with red central capsule and +numerous xanthellae, was observed living by me at the Canary Islands.) + +_Dimensions._--Height of the frontal ring 0.1 to 0.12, breadth 0.14 to +0.17. + +_Habitat._--Cosmopolitan; Atlantic, Indian, Pacific, surface and at various +depths. + + + +{979}Genus 419. _Plectocoronis_,[38] Haeckel, 1881, Prodromus, p. 445. + +_Definition._--#Coronida# with six large, partly latticed gates (four +lateral and two basal). Skeleton composed of two complete rings (the +sagittal and basal) and one incomplete (frontal) ring. Basal ring without +developed typical feet. + +The genus _Plectocoronis_ differs from the preceding _Eucoronis_, its +ancestral form, in the development of loose irregular lattice-work along +the two meridional rings, and therefore bears to it the same relation that +_Acanthodesmia_ does to _Coronidium_. If the lattice-work become more +complete and close the gates, these Coronida pass over directly into +#Spyroidea# (Zygospyrida). + + +1. _Plectocoronis anacantha_, n. sp. + +Basal ring and frontal ring elliptical, without sagittal constriction. +Sagittal ring ovate. The frontal and sagittal rings are bordered on both +edges with an incomplete series of small irregular pores. All three rings +smooth, without spines. + +_Dimensions._--Height of the frontal ring 0.1, breadth 0.16. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + +2. _Plectocoronis triacantha_, n. sp. + +Basal ring and frontal ring nearly circular, without sagittal constriction. +Sagittal ring elliptical, prolonged at the apex into an apical horn from +which two branched lateral bows descend and unite with the uppermost parts +of the frontal ring. Four other small bows descend from the lowermost parts +of the latter and unite with the basal ring. From the lateral corners of +the basal ring descend two short vertical feet. (May be regarded as derived +from _Podocoronis toxarium_, Pl. 83, Fig. 7, by development of the bows +connecting the rings.) + +_Dimensions._--Height of the frontal ring 0.11, breadth 0.13. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +3. _Plectocoronis pentacantha_, n. sp. (Pl. 93, fig. 6). + +Basal ring and frontal ring kidney-shaped, with deep sagittal constriction. +Sagittal ring ovate, prolonged at the apex into an oblique horn. From the +edges of the angular rings delicate threads arise, which anastomose and +form irregular arachnoidal meshes, partly closing the four open lateral +gates. Two basal gates simple. From the four nodal points of the basal ring +there arise four, short diverging feet, comparable to rudimentary cortinar +feet (two lateral from the frontal ring and two sagittal from the primary +ring, as basal prolongations). + +_Dimensions._--Height of the frontal ring 0.12, breadth 0.18. + +_Habitat._--Central Pacific, Station 271, surface. + + + +{980}Genus 420. _Podocoronis_,[39] Haeckel, 1881, Prodromus, p. 445. + +_Definition._--#Coronida# with six large gates (four lateral and two +basal). Skeleton composed of two complete rings (the sagittal and basal) +and one incomplete (frontal) ring. Basal ring provided with typical, +regularly disposed, descending feet (cortinar feet). + +The genus _Podocoronis_ differs from the two preceding nearly allied genera +in the development of typical radial feet on the basal ring, which by their +regular disposition and their general appearance among the #Spyroidea# and +#Cyrtoidea# obtain great morphological importance. According to the +different number and disposition of these basal feet (or "cortinar feet"), +the following subgenera may be distinguished (regarded in my Prodromus, +1881, p. 445, as separate genera):--_Dipocoronis_ with two lateral feet, +_Tripocoronis_ with three cortinar feet (most important!), _Tetracoronis_ +with four crossed feet, _Hexacoronis_ with six radial feet, _Stylocoronis_ +with numerous (8 or more feet). These subgenera have important relations to +the corresponding genera of Zygospyrida. + + + +Subgenus 1. _Dipocoronis_, Haeckel, 1881, Prodromus, p. 445. + +_Definition._--Basal ring with two descending lateral feet (right and left) +as prolongations of the frontal ring. + + +1. _Podocoronis dipodiscus_, n. sp. + +Basal ring nearly circular, with two conical, straight, parallel descending +feet, which are direct lateral prolongations of the subcircular frontal +ring, and half as long as it. The ovate sagittal ring bears at the apex a +short conical vertical horn. All rings nearly smooth. + +_Dimensions._--Height of the frontal ring 0.12, breadth 0.14. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +2. _Podocoronis toxarium_, n. sp. (Pl. 83, fig. 7). + +Basal ring elliptical, with two descending, slightly curved conical feet, +lateral prolongations of the subcircular frontal ring. The ovate sagittal +ring bears at the apex a cylindrical vertical horn, which is connected by +two descending lateral arches (or galear arches) with the uppermost part of +the frontal ring. + +_Dimensions._--Height of the frontal ring 0.1, breadth 0.13. + +_Habitat._--Central Pacific, Stations 265 to 268, depth 2900 fathoms. + + + +{981}Subgenus 2. _Tripocoronis_, Haeckel, 1881, Prodromus, p. 445. + +_Definition._--Basal ring with three descending feet (one caudal and two +pectoral). + + +3. _Podocoronis cortiniscus_, n. sp. (Pl. 97, fig. 2). + +Basal ring violin-shaped, with three straight divergent thorny feet, about +as long as the ovate sagittal ring. The dorsal part of the latter is +straight, vertical, and prolonged downwards into the caudal foot, upwards +into a stout, thorny, vertical apical horn. The ventral part is +semicircular and gives off the lateral branches, forming the kidney-shaped +sagittal ring. All the rings and their apophyses are armed with stout +thorns. This and the following tripodal species may be directly derived +from _Cortina_. + +_Dimensions._--Height of the frontal ring 0.1, breadth 0.15. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + +4. _Podocoronis tripodiscus_, n. sp. + +Basal ring kidney-shaped, with three large divergent curved feet, nearly +twice as long as the semicircular sagittal ring. The straight dorsal part +of the latter is prolonged downwards into the caudal foot, upwards into a +large branched apical horn, curved backwards. Differs from the preceding +species mainly in the longer curved apophyses and in the larger +violin-shaped frontal ring. + +_Dimensions._--Height of the frontal ring 0.12, breadth 0.2. + +_Habitat._--North Pacific, Station 238, surface. Fossil in Barbados. + + + +Subgenus 3. _Tetracoronis_, Haeckel, 1881, Prodromus, p. 445. + +_Definition._--Basal ring with four descending feet (two sagittal and two +lateral). + + +5. _Podocoronis tetrapodiscus_, n. sp. + +Basal ring kidney-shaped, with four stout and straight divergent feet, +about as long as the sagittal ring; two of them are lateral and arise from +the basal corners of the violin-shaped frontal ring (at its junction with +the basal ring); two are sagittal, and arise from the basal corners of the +semicircular sagittal ring (one posterior caudal and one anterior sternal). +The straight dorsal part of the sagittal ring is prolonged upwards into an +apical horn. All the rings are thorny. + +_Dimensions._--Height of the frontal ring 0.15, breadth 0.25. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + + +Subgenus 4. _Hexacoronis_, Haeckel + +_Definition._--Basal ring with six radial descending feet (two sagittal, +two pectoral, and two tergal feet). + + +{982}6. _Podocoronis hexapodiscus_, n. sp. + +Basal ring violin-shaped, with six conical, vertically descending feet, +half as long as the sagittal ring; two of them are sagittal (arising from +the two basal corners of the sagittal ring, caudal and sternal feet); the +other four are lateral, and prolongations of the forked basal parts of the +frontal ring, which is inserted on the basal ring with two forked branches; +the anterior correspond to the pectoral, the posterior to the tergal feet +of _Hexaspyris_. All the rings are thorny. + +_Dimensions._--Height of the frontal ring 0.11, breadth 0.17. + +_Habitat._--South Pacific, Station 295, depth 1500 fathoms. + + + +Subgenus 5. _Stylocoronis_, Haeckel. + +_Definition._--Basal ring with numerous (eight to twelve or more) +descending feet. + + +7. _Podocoronis petalospyris_, n. sp. + +Basal ring violin-shaped, with ten to twelve flat lamellar, vertically +descending feet, about as long as the ovate sagittal ring. Frontal ring +twice as broad as long, elliptical. All rings nearly smooth. Similar to a +_Petalospyris_ without lattice-work. + +_Dimensions._--Height of the frontal ring 0.1, breadth 0.2. + +_Habitat._--Fossil in Barbados. + + +8. _Podocoronis polypodiscus_, n. sp. + +Basal ring elliptical, with fifteen to eighteen conical, curved, descending +feet, half as long as the ovate sagittal ring. Frontal ring kidney-shaped, +one and a half times as broad as long. All the rings armed with short +conical spines. + +_Dimensions._--Height of the frontal ring 0.12, breadth 0.18. + +_Habitat._--Central Pacific, Station 273, depth 2350 fathoms. + + + +Subfamily 4. TRISSOCYCLIDA, Haeckel, 1881, Prodromus, p. 446. + +_Definition._--#Coronida# with eight large gates (four superior lateral and +four inferior basal). Skeleton composed of three complete rings, +perpendicular to one another; two of which are vertical (the primary or +sagittal and the secondary or frontal ring), the third is horizontal (the +tertiary or basal ring). + + + +Genus 421. _Tristephanium_,[40] Haeckel, 1881, Prodromus, p. 445. + +_Definition._--#Coronida# with eight large, simple gates of different +sizes; the four upper or lateral gates larger than the four lower or basal +gates. Skeleton composed of three simple complete rings, perpendicular to +one another. + +{983}The genus _Tristephanium_, and the three following genera derived from +it, represent together the interesting subfamily of Trissocyclida +(Prodromus, 1881, p. 446). These differ from all other Coronida in the +possession of three complete rings, perpendicular to one another. The first +of these is the vertical sagittal ring, the second the vertical frontal +ring, and the third the horizontal basal ring. Since these three rings lie +in the three dimensive planes, they are perpendicular to one another; and +between them remain eight large open gates. Originally the four upper or +lateral gates (corresponding to those of _Zygostephanus_) are much larger, +the four lower or basal gates (corresponding to those of _Semantrum_) much +smaller; but afterwards the latter may reach the size of the former, so +that the basal ring becomes equatorial (in _Trissocircus_ and +_Trissocyclus_). The common ancestral form of the Trissocyclida +(_Tristephanium_) may be derived directly either from _Semantrum_ (by +complete development of the frontal ring) or from _Eucoronis_ (by complete +development of four basal gates). + + + +Subgenus 1. _Triostephus_, Haeckel, 1881, Prodromus, p. 445. + +_Definition._--Sagittal and frontal ring of different size and form. + + +1. _Tristephanium dimensivum,_ n. sp. (Pl. 93, fig. 9). + +Sagittal ring ovate, with a large thorny apical horn, smaller than the two +other rings. Frontal ring violin-shaped, with a deep sagittal constriction. +Basal ring also violin-shaped, in the sagittal axis constricted. Its four +gates (two jugular and two cardinal) of nearly equal size. All three rings +angular, armed with scattered, stout, thorny spines, which are larger in +the basal half. + +_Dimensions._--Height of the frontal ring 0.08, breadth 0.12. + +_Habitat._--North Pacific, Station 241, depth 2300 fathoms. + + +2. _Tristephanium octopyle,_ n. sp. (Pl. 93, fig. 8). + +Sagittal ring ovate, nearly smooth, smaller than the two other rings. +Frontal ring kidney-shaped, with a deep basal constriction. Basal ring +violin-shaped. The jugular gates about half as large as the cardinal gates. +Rods of the rings cylindrical, with few scattered thorns. + +_Dimensions._--Height of the frontal ring 0.09, breadth 0.14. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +3. _Tristephanium hertwigii,_ Haeckel. + + _Acanthodesmia hertwigii_, Buetschli, 1882, Zeitschr. f. wiss. Zool., + vol. xxxvi. pp. 499, 539, Taf. xxxii. figs. 9_a_-9_c_. + +Sagittal ring ovate or nearly semicircular; its dorsal rod straight, smooth +(fig. 9_c_, _a_), its ventral rod (_b_) curved, thorny. Frontal ring much +larger, thorny, violin-shaped, with a slight sagittal {984}constriction. +Basal ring smaller than the sagittal ring, thorny, kidney-shaped, with four +different gates; the two cardinal pores much larger than the two jugular +pores. (The four basal pores are often much larger than in the specimen +figured by Buetschli. Also the number, form, and size of the spines is very +variable.) + +_Dimensions._--Height of the frontal ring 0.07 to 0.09, breadth 0.17 to +0.2. + +_Habitat._--Fossil in Barbados. + + + +Subgenus 2. _Tristephaniscus_, Haeckel, 1881, Prodromus, p. 445. + +_Definition._--Sagittal and frontal ring of equal size and form. + + +4. _Tristephanium quadricorne_, n. sp. (Pl. 93, fig. 7). + +Sagittal and frontal ring of equal size and form, larger than the circular +basal ring. From the four corners, in which the latter crosses the two +former, arise four strong, divergent spines, branched like a deer's antler. +Some smaller spines are scattered on the rings, and a bunch of four spines +arises on the apical pole. The four upper gates are triangular, the four +lower nearly semicircular, the latter of equal size, half as large as the +former. + +_Dimensions._--Height of the frontal ring 0.13, breadth 0.14. + +_Habitat._--South Atlantic, Station 342, depth 1445 fathoms. + + + +Genus 422. _Tricyclidium_,[41] Haeckel, 1881, Prodromus, p. 446. + +_Definition._--#Coronida# with eight large, partly fenestrated gates; the +four upper or lateral gates larger than the four lower or basal gates. +Skeleton composed of three latticed complete rings, perpendicular to one +another. + +The genus _Tricyclidium_ differs from the preceding _Tristephanium_, its +ancestral form, in the development of loose rudimentary lattice-work along +the rings, and therefore bears to it the same relation that _Plectocoronis_ +does to _Eucoronis_. It may pass directly over into _Dictyospyris_. + + +1. _Tricyclidium dictyospyris_, n. sp. (Pl. 93, fig. 13). + +Sagittal ring ovate, twice as thick as the two other larger rings, which +become very thin, thread-like at the lateral junction, and are both +slightly violin-shaped, in the middle sagittal plane constricted; the +frontal ring larger than the basal. All three rings bear small scattered +spines, which are irregularly branched, and by anastomoses of the +thread-like branches form small irregular meshes along the rings. The four +basal gates are of equal size. + +_Dimensions._--Height of the frontal ring 0.11, breadth 0.15. + +_Habitat._--Equatorial Atlantic, Station 347, depth 2250 fathoms. + + +{985}2. _Tricyclidium semantrum_, n. sp. + +Sagittal ring ovate, smaller than the violin-shaped frontal ring and larger +than the elliptical basal ring. All three rings of nearly equal thickness, +armed with short irregular branches, which are partly connected, and +forming small irregular meshes along the rings. The four basal gates are of +different sizes; the two anterior (jugular) gates only half as large as the +two posterior (cardinal) gates. + +_Dimensions._--Height of the frontal ring 0.12, breadth 0.18. + +_Habitat._--South Atlantic, Station 348, depth 2450 fathoms. + + + +Genus 423. _Trissocircus_,[42] Haeckel, 1881, Prodromus, p. 446. + +_Definition._--#Coronida# with eight large simple gates of equal size. +Skeleton composed of three simple complete rings, perpendicular to one +another. + +The genus _Trissocircus_, and the following nearly allied _Trissocyclus_, +differ from the two preceding ancestral genera in the remarkable growth of +the four basal gates, which reach the size of the lateral gates. Therefore +both hemispheres of the shell (the upper or apical and the lower or basal) +here become equal and the basal ring becomes equatorial. Sometimes even all +three rings attain the same size, so that it is difficult or impossible to +distinguish them. In this curious case the Coronida exhibit a striking +resemblance to some #Sphaeroidea#. + + + +Subgenus 1. _Tricircarium_, Haeckel. + +_Definition._--Sagittal ring smaller than the two other rings, which are +both elliptical. + + +1. _Trissocircus lentellipsis_, n. sp. (Pl. 93, fig. 10). + +All three rings elliptical, of different sizes, smooth, without spines. The +sagittal ring is the smallest, but two to three times as thick as the other +two rings, which have the larger (transverse) axis common. The smaller +(sagittal) axis of the sagittal ring is also the smaller axis of the +equatorial ring, whilst the larger (principal) axis of the former is the +smaller axis of the frontal ring. + +_Dimensions._--Height of the frontal ring 0.07, breadth 0.1. + +_Habitat._--Western Tropical Pacific, Station 224, depth 1850 fathoms. + + +2. _Trissocircus binellipsis_, n. sp. (Pl. 83, fig. 6). + +Sagittal ring circular, smaller than the other two rings, which are both +equal, elliptical, slightly constricted on the poles of the principal and +transverse axes. The axis of the circular sagittal {986}ring is the shorter +axis of the frontal and equatorial ring, and about half as long as their +longer axis. All three rings smooth, without spines. + +_Dimensions._--Height of the frontal ring 0.08, breadth 0.12. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +3. _Trissocircus octostoma_ (Pl. 93, fig. 11). + +Sagittal ring circular, smaller than the other two rings, which are both +equal, elliptical, distinctly constricted at the poles of the principal and +transverse axes. The axis of the circular sagittal ring is the shorter axis +of the frontal and equatorial ring, about one-third shorter than their +longer axis. All three rings armed with short, irregularly branched spines. + +_Dimensions._--Height of the frontal ring 0.1, breadth 0.12. + +_Habitat._--Indian Ocean, Ceylon (Belligemma), Haeckel, surface. + + + +Subgenus 2. _Tricirconium_, Haeckel. + +_Definition._--All three rings equal, circular. + + +4. _Trissocircus octahedrus_, n. sp. + +All three rings equal, circular, smooth, their rods cylindrical (in the +transverse section circular). From each pole of the three equal axes arises +a short conical spine; these six spines correspond to the six corners of a +regular octahedron. + +_Dimensions._--Diameter of all three rings 0.08, thickness 0.006. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +5. _Trissocircus globus_, n. sp. (Pl. 82, fig. 13). + +All three rings equal, circular, thorny; their rods prismatic (in the +transverse section triangular), with three sharp dentated edges and +scattered branched thorns. From each pole of the three equal axes (which +correspond to the three axes of a regular octahedron) arises a bunch of +larger spines. + +_Dimensions._--Diameter of all three rings 0.12, thickness 0.01. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + + +Genus 424. _Trissocyclus_,[43] Haeckel, 1881, Prodromus, p. 446. + +_Definition._--#Coronida# with eight large, partly fenestrated gates of +equal size. Skeleton composed of three complete latticed rings, +perpendicular to one another. + +The genus _Trissocyclus_ differs from its nearly allied ancestral form +_Trissocircus_ only in the development of small anastomosing branches along +the edges of the rings. The incomplete lattice-work, produced by these +anastomoses, partly protects the eight large gates. The three rings are +either of equal or of different sizes. + + + +{987}Subgenus 1. _Tricyclarium_, Haeckel. + +_Definition._--Sagittal ring circular, smaller than the other two rings, +which are both elliptical. + + +1. _Trissocyclus stauroporus_, n. sp. (Pl. 83, fig. 5). + +Sagittal ring circular, smaller than the other two equal elliptical rings. +On each of the six corners (or crossing points of every two rings) are +developed four small pores, forming a cross around the poles of the three +axes. All three rings smooth, without spines. + +_Dimensions._--Height of the frontal ring 0.09, breadth 0.13. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +2. _Trissocyclus triaxonius_, n. sp. + +Sagittal ring circular, smaller than the two other equal elliptical rings. +From the edges of all three rings are developed small branches, which by +irregular ramification and anastomoses form small irregular meshes along +the rings. Similar to _Trissocircus octostoma_, but with thicker rings; it +may be developed from the latter species by connection of the branches +which border the rings. + +_Dimensions._--Height of the frontal ring 0.12, breadth 0.15. + +_Habitat._--South Pacific, Station 298, depth 2225 fathoms. + + + +Subgenus 2. _Tricyclonium_, Haeckel. + +_Definition._--All three rings equal, circular. + + +3. _Trissocyclus sphaeridium_, n. sp. (Pl. 93, fig. 12). + +All three rings equal, circular, thorny; their rods prismatic, three-sided, +with three denticulate edges; the teeth of the lateral edges become +branched, and form by anastomoses of the branches small irregular meshes, +which partly protect the eight large open gates. + +_Dimensions._--Diameter of the three rings 0.16, thickness 0.012. + +_Habitat._--Indian Ocean, Belligemma, Ceylon (Haeckel), surface + + + +Family LI. #TYMPANIDA#, Haeckel. + + _Parastephida_, Haeckel, 1881, Prodromus, p. 446. + +_Definition._--#Stephoidea# with two parallel horizontal rings, an upper +mitral and a lower basal ring; both connected by complete or incomplete +vertical rings, or by parallel vertical columellae. + +{988}The family #Tympanida# (or Parastephida) differs from the other +#Stephoidea# in the development of two horizontal rings, which lie in +horizontal planes and arise from the upper and the lower poles of the +primary sagittal ring. Therefore the same formation, which we found in the +Semantida on the basal pole only of the main axis, here takes place also on +its apical pole. On both poles arise at each side from the sagittal ring +two corresponding pairs of curved branches: the lateral ends of the +opposite branches (dorsal and ventral branch) become united in the frontal +plane and so form two complete horizontal rings. The upper ring, composed +of the superior or mitral branches, may be called the mitral ring, the +lower ring, formed by the inferior or basal branches, the basal ring. Both +rings are commonly of nearly equal size, more rarely of different sizes. +Their connection is effected either by the primary (sagittal) ring only, or +also by secondary vertical rings, a frontal ring in the lateral plane, or +some diagonal meridian rings between the latter and the former. These +vertical rings, which connect both horizontal rings in the form of +"columellae," may be either complete or incomplete; in the latter case +their apical and basal parts are lost, the dorsal and ventral parts only +being preserved. + +The Tympanida develop a great variety of different forms, greater than in +the three other families of #Stephoidea#, so that we may distinguish here +not less than sixteen genera and seventy-two species. Hitherto only three +species were known: _Prismatium tripleurum_, figured in 1862 in my +Monograph, _Tympanidium barbadense_, figured by Bury in the "fossil +Polycystins of Barbados," and _Tympaniscus fibula_, described in 1875 by +Ehrenberg as a _Ceratospyris fibula_. The number of species in this large +and richly developed group will be considerably augmented by further +researches. A great many of them exhibit remarkable relations to different +NASSELLARIA. For better survey of the whole family we distinguish here four +subfamilies, the first of which (Protympanida) is probably the common +ancestral group of the other three. They may have been derived originally +either from the Semantida or directly from the Stephanida. + +The first subfamily, Protympanida, exhibits a complete primary or vertical +sagittal ring, bearing on the upper part a horizontal mitral ring, on the +lower part a horizontal basal ring. Therefore the gates of these two +parallel rings become bisected by the sagittal ring, each divided into a +right and a left half. The sagittal ring itself becomes divided by the two +horizontal rings into four parts or rods; two opposite of these are more or +less vertical; the dorsal (posterior) and the ventral (anterior) rod; the +two other rods are more or less horizontal; the mitral (upper) and the +basal (lower) rod. + +In _Protympanium_ (Pl. 93, fig. 14), the simplest and most primitive form +of Tympanida, the connection of the two horizontal rings is effected only +by the dorsal and ventral rods of the sagittal ring forming two parallel +more or less vertical "columellae." In all other Protympanida accessory +columellae are developed between the latter. In the greater number we find +two secondary columellae in the lateral plane, being the lateral +{989}segments of an incomplete frontal ring (_Acrocubus_, Pl. 93, figs. +15-17). Between the latter and the former there are sometimes developed +four tertiary columellae, as segments of two crossed incomplete diagonal +rings (_Tympanidium_, Pl. 94, figs. 1, 18). At other times we find six +columellae; here probably the frontal ring is cleft into halves on each +side (_Tympaniscus_, Pl. 94, figs. 4-7). Some genera are distinguished by +the development of an equatorial ring, or a third horizontal ring (between +the upper mitral and the lower basal ring); this equatorial ring is either +complete (_Microcubus_ Pl. 94, figs. 8-10) or incomplete, developed only +laterally (_Octotympanum_, Pl. 94, figs. 2, 3). The genus _Toxarium_ (Pl. +93, figs. 18-20) is distinguished by the development of accessory pairs of +bows in the frontal plane, upper or galear bows and lower or thoracal bows, +remarkable as beginnings of the accessory joints, which we distinguish in +many #Spyroidea# and #Cyrtoidea# as "galea and thorax." + +The second subfamily of Tympanida are the Paratympanida, in which the two +horizontal rings become closed by lattice-work. The numerous columellae +connecting the two rings are here either divergent (_Paratympanum_, with +two unequal rings, Pl. 94, fig. 14) or parallel and vertical +(_Lithotympanum_, with two equal rings, Pl. 83, fig. 1). The shell of the +latter assumes the form of a drum. + +A third small subfamily, Dystympanida, is represented by a single genus +only, _Dystympanium_ (Pl. 94, figs. 15, 16). Here only the upper or mitral +ring is closed by lattice-work, whilst the lower or basal ring exhibits +quite a simple opening, a large "basal gate" which has probably arisen by +loss of the basilar rod of the sagittal ring. These curious forms exhibit a +remarkable resemblance to some Monocyrtida, and also to the _Dictyocha_ +(PHAEODARIA). + +The fourth subfamily, the Eutympanida, are distinguished by the simple wide +aperture of the two horizontal rings; the upper enclosing a simple "mitral +gate," the lower a simple "basal gate." Here probably the two horizontal +parts of the sagittal ring (the upper mitral rod and the lower basilar rod) +are lost by reduction; its two vertical parts (the dorsal and ventral rods) +only remaining and forming the two parallel columellae, which connect the +two horizontal rings (_Parastephanus_, Pl. 93, fig. 21). In this group also +secondary columellae are commonly developed between the two rings, +alternating with the two primary columellae. _Pseudocubus_ (Pl. 94, figs. +11, 12), resembling an obelisk, exhibits four divergent columellae; the two +sagittal of these are probably the vertical parts of the primary ring, +whilst the two lateral are the halves of an incomplete frontal ring. In +_Lithocubus_ (Pl. 82, fig. 12) the four columellae are parallel and +vertical, the two rings being equal; the shell here assumes the form of a +geometrical cube. _Prismatium_ is distinguished by three parallel +columellae; two of these are probably parts of a frontal ring, whilst the +third is the remains of a reduced sagittal ring. In _Circotympanum_ (Pl. +94, fig. 17) and in _Lithotympanum_ (Pl. 82, fig. 11) the number of the +columellae is augmented, there being six to eight or more; in the former +they are divergent {990}(the two rings being of different sizes), in the +latter parallel (the two rings being equal); the fundamental form of the +former is a truncated pyramid, of the latter a prism. + +Comparing these differences between the four subfamilies of Tympanida, we +may suppose that the common ancestral group are the Protympanida, derived +from the Semantida by the formation of a mitral ring. If the two horizontal +rings become closed by lattice-work, the Paratympanida arise. When the +mitral ring only becomes latticed, the basal ring being simple, the +Dystympanida originate. Finally, the fourth subfamily, the Eutympanida, may +be derived from the Protympanida by the loss of the two horizontal parts of +the sagittal ring. + +The two horizontal rings (upper mitral and lower basal) and the two +vertical rings (primary sagittal and secondary frontal), which thus compose +the loose framework of the Tympanida, are rarely smooth, commonly armed +with spines or branches, similar to those of the Coronida. The rods or bars +are either roundish (with circular transverse section) or angular (commonly +with triangular transverse section). The paired branches of the two +vertical rings often preserve the characteristic arrangement inherited from +the Semantida and Stephanida. The two horizontal rings sometimes exhibit +typical apophyses, which recur in the #Spyroidea# and #Cyrtoidea#. The +mitral ring may possess one odd apical horn and two paired frontal horns +(Pl. 93, figs. 16, 17, 19, 23). The basal ring sometimes bears the three +typical feet of _Cortina_ (Pl. 93, figs. 16, 22), one odd caudal foot and +two paired pectoral feet. Sometimes a fourth (sternal) foot is developed +(Pl. 94, fig. 4), at other times only two lateral feet (Pl. 94, figs. 5, +6). + +_Synopsis of the Genera of Tympanida._ + + ------------------------------------------------------------------------- + I. Subfamily Protympanida. + Two horizontal rings (upper mitral ring and lower basal ring) + bisected by the complete sagittal ring. + ------------------------------------------------------------------------- + Two horizontal rings {One complete sagittal + connected by two { ring (no frontal + columellae. { ring), 425. _Protympanium_. + + } {No galear and + Two horizontal} { thoracal bows, 426. _Acrocubus_. + rings }No equatorial { + connected } ring. {Galear and + by four } { thoracal bows, 427. _Toxarium_. + columellae } + (the halves of} {Equatorial ring + the sagittal }An equatorial { complete, 428. _Microcubus_. + and the } ring. { + frontal ring).} {Equatorial ring + } { incomplete, 429. _Octotympanum_. + + {Six columellae + Two horizontal rings { (three meridional + connected by six or eight { rings), 430. _Tympaniscus_. + columellae (three or four { + vertical rings). {Eight columellae + { (four meridional + { rings), 431. _Tympanidium_. + ------------------------------------------------------------------------- + II. Subfamily Paratympanida. Two horizontal rings fenestrated. + ------------------------------------------------------------------------- + {Two rings unequal + Two horizontal rings closed { (columellae + by a lattice-plate, { divergent), 432. _Paratympanum_. + connected by numerous { + columellae. {Two rings equal + { (columellae + { parallel), 433. _Lithotympanum_. + + + + + III. Subfamily Dystympanida. Mitral ring fenestrated, basal ring simple. + ------------------------------------------------------------------------ + Two horizontal rings } Mitral ring closed by a + connected by numerous } lattice-plate, basal + (six to eight or more } ring simple, 434. _Dystympanium_. + columellae). } + + IV. Subfamily Eutympanida. Two horizontal rings (upper mitral ring and + lower basal ring) simple. Apical and basal parts of the sagittal ring + lost. + ----- + {Two columellae (parts of + Two horizontal rings { the sagittal ring), 435. _Parastephanus_. + connected by two or { + three columellae (four {Three columellae (parts of + or five open gates). { the half sagittal and + { the frontal ring), 436. _Prismatium_. + + { {Two rings + { { unequal, 437. _Pseudocubus_. + {Four { + Two horizontal rings { columellae {Two rings + connected by four or { { equal, 438. _Lithocubus_. + more columellae (six or{ + eight or more open { {Two rings + gates). {Six to eight { unequal, 439. _Circotympanum_. + { or more { + { columellae. {Two rings + { { equal, 440. _Eutympanium_. + + + +Subfamily 1. PROTYMPANIDA, Haeckel. + +_Definition._--#Tympanida# with two bisected horizontal rings, connected by +the complete vertical sagittal ring. (The upper mitral ring and the lower +basal ring become divided by the complete primary or sagittal ring into two +horizontal symmetrical gates, two mitral gates on the apical and two basal +gates on the basal pole.) + + + +Genus 425. _Protympanium_,[44] Haeckel, 1881, Prodromus, p. 447 (_sensu +emend._). + +_Definition._--#Tympanida# with two bisected horizontal rings, connected by +two vertical columellae. + +The genus _Protympanium_, is the most simple form of all Tympanida, and +probably the common ancestral form of this family. It arises from +_Lithocircus_ by the development of two horizontal rings, perpendicular to +the primary sagittal ring. The upper or mitral ring arises by lateral union +of two pairs of superior branches, the lower or basal ring by union of two +pairs of basal branches of the primary vertical ring. + + +1. _Protympanium primordiale_, n. sp. + +Mitral and apical ring of equal size, elliptical, smooth, somewhat smaller +than the connecting thorny sagittal ring. + +_Dimensions._--Diameter of the two horizontal rings 0.12, of the sagittal +ring 0.15. + +_Habitat._--Central Pacific, Stations 263 to 274, at various depths. + + +{992}2. _Protympanium amphipodium_, n. sp. (Pl. 93, fig. 14). + +Mitral and apical rings of equal size, thin, elliptical, smooth, larger +than the broad connecting sagittal ring. The latter bears on the apical and +on the basal pole two divergent straight spines (lying in the frontal +plane), the two apical (or horns) somewhat smaller and not so spiny as the +two basal spines (or feet). In the frontal plane there arise from the two +horizontal rings on each side two small opposite spines (remnants or +beginnings of the lateral frontal ring?). + +_Dimensions._--Diameter of the two horizontal rings 0.11, of the sagittal +ring 0.07. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +3. _Protympanium trissocircus_, n. sp. + +Mitral ring smaller than the basal ring; both rings circular, rough. +Sagittal ring in size between the two former. All three rings covered with +very small thorns. + +_Dimensions._--Diameter of the mitral ring 0.08, of the sagittal ring 0.1, +of the basal ring 0.12. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + + +Genus 426. _Acrocubus_,[45] Haeckel, 1881, Prodromus, p. 447. + +_Definition._--#Tympanida# with two bisected horizontal rings, connected by +four vertical columellae. No equatorial ring. + +The genus _Acrocubus_ is the most primitive of those remarkable Tympanida, +the skeleton of which represents more or less exactly the form of a +geometrical cube. A simple complete sagittal ring bears on the superior and +on the inferior part two opposite pairs of lateral branches; by union of +the convergent branches of each side there arise two horizontal parallel +quadrangular rings, which are bisected by the sagittal ring. Therefore the +superior ring encloses two triangular mitral gates, the inferior two +triangular basal gates. The lateral corners of the two gates of each side +are connected by a vertical rod or columella. These two parallel columellae +are the remaining middle parts of the secondary or frontal ring, which is +incomplete on the superior and on the inferior face of the body. If the +sagittal ring also become incomplete, by the loss of the superior and +inferior part (the anterior and posterior only remaining), then _Acrocubus_ +is transformed into _Lithocubus_. + + + +Subgenus 1. _Apocubus_, Haeckel. + +_Definition._--Basal ring without descending feet. + + +{993}1. _Acrocubus octopylus_, n. sp. (Pl. 82, fig. 9). + +Mitral ring somewhat smaller than the basal ring; both rings rhombic, with +curved outlines. Sagittal ring elliptical, with six pairs of nodulate +protuberances. Four columellae curved. Nodal points without radial spines. + +_Dimensions._--Height of the frontal ring 0.12, breadth 0.18. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +2. _Acrocubus tesseralis_, n. sp. + +Mitral ring of the same size as the basal ring; both rings square, smooth, +with straight outlines. Sagittal ring also square, smooth. Four columellae +straight. Nodal points without radial spines. The shell has the form of a +regular geometrical cube, the edges of which are represented by the rings. + +_Dimensions._--Height of the frontal ring 0.1, breadth 0.11. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms. + + + +Subgenus 2. _Dipocubus_, Haeckel. + +_Definition._--Basal ring with two descending feet. + + +3. _Acrocubus brachiatus_, n. sp. + +Mitral ring smaller than the basal, both rings square, with thick straight +rods. Sagittal ring tuberculate, square, equatorial part thinner. Four +columellae curved, the two lateral ones prolonged downwards into two +vertical parallel straight feet of half their length. + +_Dimensions._--Diameter of the cube 0.12; length of the feet 0.06. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +4. _Acrocubus amphistylus_, n. sp. + +Mitral and basal rings of nearly equal size, square, with thick curved +rods. Sagittal ring elliptical, in the equatorial part thinner. Frontal +ring tuberculate. Four columellae curved, the two lateral ones prolonged +downwards into two vertical, tuberculate feet of half their length. + +_Dimensions._--Diameter of the cube 0.13; length of the feet 0.07. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +5. _Acrocubus arcuatus_, n. sp. (Pl. 93, fig. 15). + +Mitral and basal rings, as well as the sagittal ring, of the same form as +in the preceding nearly allied species. The two lateral columellae are +prolonged not only downwards into two short {994}vertical feet, but also +upwards into two curved bows, which are united in a vertical ascending +horn, arising from the apical pole of the sagittal ring. + +_Dimensions._--Diameter of the cube 0.14; total height 0.21. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + + +Subgenus 3. _Tripocubus_, Haeckel. + +_Definition._--Basal ring with three descending feet (one odd caudal and +two paired lateral). + + +6. _Acrocubus lasanum_, n. sp. + +Mitral ring smaller than the basal, both rings square, with curved rods. +Sagittal ring ovate, prolonged upwards into an occipital simple horn, +downwards into a caudal foot. Two lateral columellae prolonged downwards +into two pectoral feet. All three feet conical, about as long as the height +of the cube. + +_Dimensions._--Diameter of the cube 0.08; length of the feet 0.07. + +_Habitat._--North Pacific, Station 241, depth 2300 fathoms. + + +7. _Acrocubus cortina_, n. sp. (Pl. 93, fig. 16). + +Mitral ring smaller than the basal, both rings elliptical, with curved +rods. Sagittal ring ovate, prolonged upwards into an occipital horn, +downwards into a caudal foot, as in the preceding species. As in the +latter, also, the two lateral columellae are prolonged downwards into two +pectoral feet, but also upwards into two convergent horns, which are united +with the occipital horn (commencing the formation of a galea). Rings and +feet somewhat thorny. + +_Dimensions._--Diameter of the cube 0.16; total height 0.2. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + + +Subgenus 4. _Tetracubus_, Haeckel. + +_Definition._--Basal ring with four descending feet (two sagittal and two +lateral). + + +8. _Acrocubus tetrapodius_, n. sp. + +Mitral and basal rings of the same size, square, with straight rods, +sagittal ring also square. The four vertical columellae are nearly parallel +and straight, prolonged upwards into four short conical horns, downwards +into four longer conical feet. (The shell has nearly the form of a +geometrical cube, the eight corners of which are prolonged into eight +vertical conical spines, four smaller ascending and four larger +descending.) + +_Dimensions._--Diameter of the cube 0.09; length of the feet 0.06. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +{995}9. _Acrocubus amphithectus_, n. sp. (Pl. 93, fig. 17). + +Mitral ring smaller than the basal, both rings elliptical, with curved +rods. Four columellae thorny, also curved, divergent downwards, prolonged +upwards into four thorny convergent horns, downwards into four larger +branched divergent feet. The two sagittal horns and feet (anterior and +posterior) are smaller than the two lateral (right and left); therefore the +fundamental form of this species is distinctly amphithect (as in the +_Ctenophora_). + +_Dimensions._--Breadth of the cube 0.12; total height 0.2. + +_Habitat._--South Pacific, Station 289, depth 2550 fathoms. + + + +Genus 427. _Toxarium_,[46] n. gen. + +_Definition._--#Tympanida# with two bisected horizontal rings, connected by +four vertical columellae. In the frontal plane two galear bows project +upwards, and two thoracal bows downwards. + +The genus _Toxarium_ differs from its ancestral form _Acrocubus_ in the +development of two pairs of peculiar bows, placed in the lateral or frontal +plane; the upper pair projects above the mitral gates, and may be called +the "galear bows," the lower pair projects below the basal gates of the +cubical shell, and may be called the "thoracal bows." Both pairs are +produced originally by the development of two forked vertical spines, +arising in the frontal plane on both poles of the principal axis from the +sagittal ring (compare _Protympanium amphipodium_, Pl. 93, fig. 14). The +apical fork-branches become connected with the lateral corners of the +mitral gates, the basal branches with those of the basal gates. By +development of lattice-work between the bows and the rings some #Spyroidea# +(_Amphispyris_, &c.) may have arisen. The important genus _Toxarium_ may be +divided into three subgenera. In _Toxellium_ all the bows are simple, in +_Toxonium_, all are forked; in _Toxidium_, the galear bows are simple, the +thoracal bows forked. + + + +Subgenus 1. _Toxellium_, Haeckel. + +_Definition._--Galear and thoracal bows simple. + + +1. _Toxarium circospyris_, n. sp. (Pl. 88, fig. 1). + +Galear and thoracal bows simple, of about the same size as the frontal bows +between them; all bows armed with scattered simple conical spines. Sagittal +constriction deep, half as long as the whole shell. Lateral outlines of the +shell nearly parallel. + +_Dimensions._--Length of the shell 0.16, breadth 0.13. + +_Habitat._--Central Pacific, Stations 265 to 274, depth 2350 to 2925 +fathoms. + + +{996}2. _Toxarium subcirculare_, n. sp. + +Galear and thoracal bows simple, armed with scattered simple spines of +about equal size, smaller than the smooth frontal bows between them. +Sagittal constriction very flat. Therefore the frontal perimeter of the +shell is nearly circular. + +_Dimensions._--Length of the shell 0.15, breadth 0.14. + +_Habitat._--North Atlantic (Antilles), Weber, surface. + + +3. _Toxarium thorax_, n. sp. (Pl. 93, fig. 18). + +Galear bows simple, smaller than the frontal bows, and these again smaller +than the simple thoracal bows; therefore the shell increases in breadth +towards the base, and resembles the skeleton of the thorax of one of the +higher vertebrates (the bow-pairs corresponding to rib-pairs, the ventral +part of the sagittal ring to the sternum, the dorsal part to the vertebral +column). Sagittal constriction very deep. All bows are armed with +scattered, irregularly branched spines. + +_Dimensions._--Length of the shell 0.17, breadth 0.2. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +4. _Toxarium constrictum_, n. sp. + +Galear and thoracal bows simple, of nearly equal size, larger than the +frontal bows between them. Therefore the shell is constricted in the +equatorial plane. Sagittal constriction also deep. All bows armed with +scattered, irregularly branched spines. + +_Dimensions._--Length of the shell 0.14, breadth 0.12. + +_Habitat._--North Pacific, Station 236, surface. + + + +Subgenus 2. _Toxidium_, Haeckel. + +_Definition._--Galear bows simple, thoracal bows forked. + + +5. _Toxarium cordatum_, n. sp. (Pl. 93, fig. 19). + +Galear bows simple, thoracal bows forked, both somewhat smaller than +frontal bows; all bows armed with scattered simple conical spines, mostly +developed at the thoracal bows. Both galear bows are united in a central +vertical columella, which arises from the apex of the sagittal ring, and is +prolonged into an apical horn. Therefore the sagittal constriction exists +only in the basal half of the inversely cordate shell. + +_Dimensions._--Length of the shell 0.18, breadth 0.16. + +_Habitat._--South Atlantic, Station 348, depth 2450 fathoms. + + +{997}6. _Toxarium furcatum_, n. sp. + +Galear bows simple, thoracal bows forked, both somewhat broader than the +frontal bows. Shell therefore slightly constricted in the equatorial plane. +Sagittal constriction rather deep, equal in the apical and basal parts. All +bows armed with scattered spines, which are partly simple, partly forked. + +_Dimensions._--Length of the shell 0.14, breadth 0.16. + +_Habitat._--Central Pacific, Station 270, depth 2925 fathoms. + + +7. _Toxarium pedatum_, n. sp. + +Galear bows simple, smaller than the frontal bows, which are again smaller +than the thoracal bows. Therefore the breadth of the shell increases +towards the base. Sagittal constriction flat in the apical part, deep in +the basal part. All bows armed with small irregularly scattered spines; at +the base six larger divergent feet (two lateral, two anterior, and two +posterior). + +_Dimensions._--Length of the shell 0.17, breadth 0.15. + +_Habitat._--South Pacific, Station 295, depth 1500 fathoms. + + + +Subgenus 3. _Toxonium_, Haeckel. + +_Definition._--Galear and thoracal bows forked. + + +8. _Toxarium costatum_, n. sp. + +Galear and thoracal bows forked, smaller than the frontal bows, all bows +thorny, without larger spines. Sagittal constriction on both poles deep. +Lateral outlines of the shell nearly parallel. + +_Dimensions._--Length of the shell 0.15, breadth 0.12. + +_Habitat._--Indian Ocean, Socotra (Haeckel), surface. + + +9. _Toxarium bifurcum_, n. sp. (Pl. 93, fig. 20). + +Galear and thoracal bows forked, the former smaller than the frontal bows, +the latter larger. Sagittal constriction rather flat on the apical pole, +which bears a vertical forked horn, very deep on the basal pole of the +primary ring. All bows armed with numerous spines, which are partly simple, +partly forked, and mainly developed at the basal part of the thoracal bows. + +_Dimensions._--Length of the shell 0.2, breadth 0.2. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +Genus 428. _Microcubus_,[47] Haeckel, 1881, Prodromus, p. 447. + +_Definition._--#Tympanida# with two bisected horizontal rings, connected by +four vertical columellae, which are bisected again by an equatorial ring. + +{998}The genus _Microcubus_ is derived from its ancestral form _Acrocubus_ +by development of a third horizontal ring, which lies in the equatorial +plane, parallel to the upper mitral and the lower basal ring. Whilst these +latter are both bisected by the complete vertical sagittal ring, the +equatorial ring is complete, and connected at the poles of the sagittal +axis with the principal ring, and at the poles of the transverse axis with +the frontal ring. Therefore the shell exhibits not eight large gates as in +_Acrocubus_, but twelve, viz., four horizontal gates (two superior mitral +and two inferior basal), four upper vertical gates (between the mitral and +the equatorial ring), and four lower vertical gates (between the basal and +the equatorial ring). + + +1. _Microcubus dodecastoma_, n. sp. (Pl. 94, fig. 9). + +All twelve gates simple, irregularly ovate or pentagonal. Frontal ring on +the sides concave, constricted by the equatorial ring. All rings curved, +armed with short irregular thorns. No larger basal spines. + +_Dimensions._--Length of the shell 0.13, breadth 0.15. + +_Habitat._--Central Pacific, Stations 271 to 274, depth 2350 to 2750 +fathoms. + + +2. _Microcubus pentacircus_, n. sp. + +All twelve gates simple. Frontal ring on the sides convex, not constricted +by the equatorial ring. All rings tuberculate, with irregular roundish +knots. No larger basal spines. Similar to the preceding species; but the +five rings are much thicker and tuberculate (not thorny); the twelve gates +are therefore relatively smaller. + +_Dimensions._--Length of the shell 0.1, breadth 0.12. + +_Habitat._--Fossil in Barbados. + + +3. _Microcubus zonarius_, n. sp. (Pl. 94, fig. 8). + +All twelve gates simple, ovate. Frontal ring on the sides convex, not +constricted by the equatorial ring, nearly twice as broad as long. All +rings thorny, very thin, except only the broad angular sagittal ring. No +larger basal spines. + +_Dimensions._--Length of the shell 0.08, breadth 0.15. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +4. _Microcubus quadrupes_, n. sp. + +All twelve gates simple, square. Frontal ring square, not constricted by +the equatorial ring. All rings smooth, quadrangular. Basal ring with four +short vertical conical feet, two of which (right and left) are inferior +prolongations of the frontal ring, and arise from the lateral corners of +the {999}basal gates; two others are prolongations of the sagittal ring +(sternal and caudal), and arise from the medial corners of the basal gates. +(The shell is like a small cube with four feet.) + +_Dimensions._--Length of the shell 0.13, breadth 0.11. + +_Habitat._--North Pacific, Station 253, depth 3125 fathoms. + + +5. _Microcubus cornutus_, n. sp. + +Eight gates (two mitral, two basal, and four superior) simple; four +inferior gates fenestrated by arachnoidal irregular threads. Frontal ring +square, constricted on the sides by the equatorial ring. Basal ring with +four short conical vertical feet, as in the preceding species. Sagittal +ring with a vertical horn on the apex. All rings with small scattered +thorns. + +_Dimensions._--Length of the shell 0.11, breadth 0.13. + +_Habitat._--North Pacific, Station 235, surface. + + +6. _Microcubus amphispyris_, n. sp. (Pl. 94, fig. 10). + +Four gates (two mitral and two basal) simple; eight lateral gates (four +superior and four inferior) fenestrated by arachnoidal irregular threads. +Frontal ring convex, not constricted by the equatorial ring. Basal ring +with six short conical divergent feet (two sagittal and four lateral). +Sagittal ring with an apical horn. (Resembles some #Spyroidea#.) + +_Dimensions._--Length of the shell 0.08, breadth 0.12. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + + +Genus 429. _Octotympanum_,[48] n. gen. + +_Definition._--#Tympanida# with two bisected horizontal rings converging +laterally and connected in the lateral poles of the equatorial plane. Eight +large gates. + +The genus _Octotympanum_ differs from all other Tympanida in the peculiar +connection of the two horizontal rings, which here reach the maximum of +their growth, converge towards the equator, and come into direct contact on +the poles of the equatorial transverse axis. Therefore the shell appears to +be composed of three complete vertical meridian rings, the middle of which +(the sagittal ring) is free and simple; the two other (subfrontal) rings +are grown together at the lateral poles of the equatorial plane; commonly +at these poles there arises (on the right and left) a strong lateral spine, +and the base of this (or the crossing point of the two touching horizontal +rings) corresponds to the remnants of the shortened frontal ring. The +crown-shaped shell exhibits therefore eight large gates; two superior +(mitral) and two inferior basal gates, two larger anterior (facial) and two +larger posterior (occipital) gates. Seen from the lateral poles {1000}only +two of the former are visible, and represent the figure of a vertical 8; +seen from the sagittal poles, only two of the latter are visible, in the +form of a larger horizontal 8. _Octotympanum_ may be derived from +_Acrocubus_ by reduction of the lateral frontal ring to a knot (or +cross-point), and by maximal extension of the two parallel horizontal +rings, which become curved downwards laterally and touch at the lateral +poles. + + +1. _Octotympanum octospinum_, n. sp. + +Mitral gates smaller than the basal gates; upper halves of the two lateral +meridional rings smaller than the lower halves. Rings with few scattered +thorns; four larger simple spines, nearly horizontal in the equatorial +plane; two on the poles of the sagittal axis, two on the poles of the +lateral axis. Four other large spines, nearly vertical at the four +lowermost basal points of the subfrontal rings. + +_Dimensions._--Length of the shell 0.09, breadth 0.12. + +_Habitat._--Central Pacific, Station 273, depth 2350 fathoms. + + +2. _Octotympanum octonarium_, n. sp. (Pl. 94, fig. 3). + +Mitral gates of the same size as the basal gates; upper and lower halves of +the meridional rings of equal size. Rings armed with numerous stout, +thorny, simple and forked spines; four very large branched spines in the +equatorial plane, nearly horizontal, two on the poles of the sagittal, two +on the poles of the transverse axis, the latter curved downwards. + +_Dimensions._--Length of the shell 0.1, breadth 0.2. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +3. _Octotympanum arborescens_, n. sp. + +Mitral gates smaller than the basal gates, the lower halves of the lateral +rings being broader than the upper halves. Rings very spiny, armed with +numerous branched spines; ten very large arborescent spines on the lateral +rings; two on the poles of the transverse axis, eight on the prominent +corners of the diagonal axes (four upper and four lower); sagittal ring +thorny. + +_Dimensions._--Length of the shell 0.8, breadth 0.16. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + +4. _Octotympanum cervicorne_, n. sp. (Pl. 94, fig. 2). + +Mitral and basal gates of equal size, the lower and upper halves of the two +crossed lateral rings being nearly equal. Rings armed with numerous +branched spines; two very large spines, similar to the antlers of a deer, +on the poles of the lateral axis; their branches about half as large as the +whole shell. Sagittal ring nearly smooth, with few small thorns on the +poles of the main axis. + +_Dimensions._--Length of the shell 0.16, breadth 0.2. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + + +{1001}Genus 430. _Tympaniscus_,[49] n. gen. + +_Definition._--#Tympanida# with two bisected horizontal rings, which are +connected by three vertical meridional rings (or six columellae). + +The genus _Tympaniscus_ and the following _Tympanidium_ differ from all +preceding Tympanida in the multiplication of the vertical columellae, which +connect the two horizontal bisected rings. _Tympaniscus_ exhibits six +columellae, which may be regarded as halves of three meridional rings. Only +one, however, of these is complete (the sagittal ring, which bisects the +mitral and the basal ring); the two other meridional rings (placed in +diagonal planes) may be regarded as produced by lateral bifurcation of an +incomplete frontal ring; this appears to be already foreshadowed in the +preceding _Octotympanum_. + + +1. _Tympaniscus corona_, n. sp. + +Basal ring larger than the mitral ring, with numerous irregular short +spines but without descending feet. Six columellae strongly curved, in the +lower half thicker and thorny; the four lateral much thinner than the two +sagittal. Apex of the jointed sagittal ring with a conical horn. + +_Dimensions._--Length of the shell 0.08, breadth 0.11. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +2. _Tympaniscus bipes_, n. sp. + +Basal ring of about the same size as the mitral ring, with two lateral +descending feet, which are parallel and vertical, simple, without spur, +half as long as the sagittal ring. The latter is ovate, twice as long and +broad as the two circular frontal rings. + +_Dimensions._--Breadth of the shell 0.14, length 0.09. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +3. _Tympaniscus dipodiscus_, n. sp. (Pl. 94, figs. 5, 6). + +Basal ring smaller than the mitral ring, with two lateral descending feet, +which are nearly parallel and vertical, obtuse, about as long as the +sagittal ring, and which bear on the outside a horizontal spur. Sagittal +ring hexagonal, very stout, with a caudal appendix at the base, and with a +small sagittal arch, bearing a stout spinulate double knob at the apex. The +two subfrontal rings depressed, twice as broad as high, on the outside +thorny, connected at each side in the lower half by a double transverse +arch. + +_Dimensions._--Breadth of the shell 0.18, length 0.08 (with spines 0.18). + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +{1002}4. _Tympaniscus tripodiscus_, n. sp. (Pl. 94, fig. 7). + +Basal ring of about the same size as the mitral ring, with three large and +stout divergent feet (two lateral and one caudal). Sagittal ring stout, +broader than the two spiny subsagittal rings; the upper part of the latter +bears two ascending arches, which are united with the large apical horn +arising from the apex of the sagittal ring. Six columellae nearly vertical, +slightly curved on the outside; their lateral edges armed with numerous +simple or forked spines. + +_Dimensions._--Breadth of the shell 0.1, total length 0.12. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +5. _Tympaniscus quadrupes_, n. sp. (Pl. 94, fig. 4). + +Basal ring larger than the mitral ring, with four short vertical +three-sided pyramidal feet of equal size (two lateral and two sagittal); +the feet are three-sided pyramidal, with finely denticulate median edges, +and bear at the base a horizontal thorny spur. Sagittal ring at the apex +with a very large cross-shaped horn, bearing two horizontal thorny lateral +branches; the horn is supported by an anterior and a posterior arch. Six +columellae strongly curved and dentate. + +_Dimensions._--Breadth of the shell 0.15, length 0.12. + +_Habitat._--South Pacific, Station 298, depth 2225 fathoms. + + +6. _Tympaniscus fibula_, Haeckel. + + _Ceratospyris fibula_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 66, Taf. xx. fig. 3. + +Basal ring of about the same size as the mitral ring, with six large +conical descending feet; these are prolongations of the six columellae, +nearly of the same length, slightly divergent, and bear at the base a +strong horizontal spur. The six columellae are strongly curved, spiny, and +bear above small arches, which are united with the apical horn of the +sagittal ring. + +_Dimensions._--Breadth of the shell 0.09, height 0.05; total height 0.09. + +_Habitat._--Fossil in Barbados. + + +7. _Tympaniscus dodecaster_, n. sp. + +Basal ring of the same size as the mitral ring, with six very large and six +alternating smaller, slightly divergent, curved feet, about as long an the +shell; the larger are the basal prolongations of the six curved, thorny +columellae. Mitral ring spiny, not overgrown with arches, as in the similar +preceding species. + +_Dimensions._--Length of the shell 0.08, breadth 0.12. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + + +{1003}Genus 431. _Tympanidium_,[50] Haeckel, 1881, Prodromus, p. 447. + +_Definition._--#Tympanida# with two bisected horizontal rings, which are +connected by four vertical meridional rings (or eight columellae). + +The genus _Tympanidium_ differs from all other Protympanida in the +development of four vertical rings, placed in four different meridional +planes. Only one of these is complete, the primary sagittal ring; the three +others are incomplete, inserted on the two horizontal rings, which are +formed by the paired mitral and basal branches of the sagittal ring; one of +these three lies in the frontal plane, the two others in diagonal +meridional planes (between the frontal and sagittal). The shell therefore +exhibits twelve large gates, four of which are horizontal (the two superior +mitral and the two inferior basal gates); the eight others are vertical, +separated by the eight columellae, or the halves of the four meridional +rings. In the subgenus _Tympanomma_ the number of gates amounts to sixteen, +the four lateral gates being bisected by an incomplete equatorial ring. The +genus _Tympanidium_ may be derived from _Acrocubus_ by development of the +two diagonal rings (between the frontal and sagittal). + + + +Subgenus 1. _Tympanura_, Haeckel. + +_Definition._--Shell with twelve gates; the four lateral gates simple. + + +1. _Tympanidium foliosum_, n. sp. (Pl. 94, fig. 1). + +Shell with twelve gates; the four lateral gates simple. Basal gates of the +shell larger than the mitral gates. Sagittal ring ovate, much smaller than +the three other meridional rings, which are armed with numerous large +elegant spines, bearing a lanceolate leaf on a thin pedicle. The sagittal +ring bears a bunch of similar spines only at the apex, and on both poles of +the sagittal axis (in the equator) a single forked spine, with two thorny +branches. + +_Dimensions._--Length of the shell 0.09 (with spines 0.25), breadth 0.15. + +_Habitat._--South Pacific, Station 300, depth 1375 fathoms. + + +2. _Tympanidium spinosum_, n. sp. + +Shell with twelve gates; the four lateral gates simple. Basal and mitral +gates of about equal size. Shell similar to that of the preceding species, +differing mainly in the different armature; the numerous spines, covering +the convex outside of the four vertical rings, are not leaf-shaped, but +conical, short, of very variable size, partly simple, partly irregularly +branched. + +_Dimensions._--Length of the shell 0.08 (with spines 0.2), breadth 0.12. + +_Habitat._--South Pacific, Station 295, depth 1500 fathoms. + + + +{1004}Subgenus 2. _Tympanomma_, Haeckel. + +_Definition._--Shell with sixteen gates (eight median gates, paired on both +sides of the sagittal ring, and eight lateral gates, paired on both sides +of the frontal ring). The four lateral gates of the two preceding species +(subgenus _Tympanura_) are bisected in _Tympanomma_ by the lateral parts of +an incomplete equatorial ring. + + +3. _Tympanidium binoctonum_, n. sp. (Pl. 94, fig. 18). + +Shell with sixteen gates; the four lateral gates double, bisected by the +lateral parts of an incomplete equatorial ring. Basal gates nearly +rectangular, of the same breadth as the pentagonal mitral gates, but twice +as long. Equatorial outline of the shell (seen in fig. 18 from the apical +pole) octagonal. All rods of the shell thin, smooth. + +_Dimensions._--Transverse axis of the shell 0.1, sagittal axis 0.06. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +4. _Tympanidium barbadense_, Haeckel. + + "Hollow cylinder," &c., Bury, 1862, Polycystins of Barbados, pl. xvi. + fig. 1. + +Shell with sixteen gates; the four lateral gates double, bisected by an +incomplete equatorial ring. Basal gates kidney-shaped, of the same breadth +as the circular mitral gates, but twice as long. Equatorial outline of the +shell elliptical. All rods of the shell thin, smooth. + +_Dimensions._--Transverse axis of the shell 0.12, sagittal axis 0.08. + +_Habitat._--Fossil in South Naparima, Trinidad, Barbados. + + +5. _Tympanidium staurocircum_, n. sp. + +Shell with sixteen gates; the four lateral gates double, bisected by an +incomplete equatorial ring. Basal and mitral gates of the shell of about +equal size, roundish. Equatorial outline of the shell violin-shaped, with +a sagittal constriction. All rods of the shell armed with short irregular +spines. + +_Dimensions._--Transverse axis of the shell 0.12, sagittal axis 0.06. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + + +Subfamily 2. PARATYMPANIDA, Haeckel, 1881, Prodromus, p. 447. + +_Definition._--#Tympanida# with two fenestrated horizontal rings, which are +connected by a variable number of vertical rods or columellae. The shell +therefore becomes more completely latticed than in the other Tympanida, and +approaches that of the #Spyroidea#. + + + +{1005}Genus 432. _Paratympanum_,[51] Haeckel, 1881, Prodromus, p. 447. + +_Definition._--#Tympanida# with two latticed horizontal rings, connected by +numerous descending and diverging columellae; mitral ring smaller than the +basal ring. + +The genus _Paratympanum_ and the following nearly allied _Lithotympanum_ +form together the small subfamily of Paratympanida, distinguished from the +other Tympanida by the fenestration of the two parallel horizontal rings. +These rings in _Lithotympanum_ are both equal, whilst in _Paratympanum_, +the basal ring is larger than the mitral ring; therefore the connecting +rods or columellae are in the former parallel and vertical, in the latter +divergent and descending. Two opposite ones of these columellae are parts +of the primary sagittal ring, two others are parts of the lateral or +frontal ring, whilst the remainder are afterwards intercalated. +_Paratympanum_ may be derived from _Dystympanium_ by fenestration of the +basal ring. + + +1. _Paratympanum hexastylum_, n. sp. + +Six divergent columellae, about as long as the diameter of the hexagonal +mitral ring, connect it with the larger hexagonal basal ring. Lattice of +the mitral ring hemispherical, with six roundish pores, surrounding a +central apical horn. Lattice of the basal ring with one large central pore, +surrounded by numerous peripheral pores. Rings and rods smooth, without +spines. + +_Dimensions._--Length of the shell 0.07; breadth of the mitral ring 0.06, +of the basal ring 0.09. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +2. _Paratympanum octostylum_, n. sp. (Pl. 94, fig. 14). + +Eight divergent columellae, about as long as the diameter of the octagonal +mitral ring, connect it with the larger circular basal ring, and bear at +each end a divergent, strong, conical spine. Lattice-plate of both rings +slightly convex, with numerous subregular circular pores, smooth, without +surface spines. + +_Dimensions._--Breadth of the mitral ring 0.06, of the basal ring 0.09. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +3. _Paratympanum decastylum_, n. sp. + +Ten divergent columellae, only half as long as the diameter of the +decagonal mitral ring, connect it with the larger circular basal ring. +Lattice-plate of the mitral ring nearly hemispherical of the basal ring +flat, both with numerous irregular roundish pores and scattered spines. +Margin of both rings spiny. + +_Dimensions._--Breadth of the mitral ring 0.08, of the basal ring 0.1. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +{1006}Genus 433. _Lithotympanum_,[52] Haeckel, 1881, Prodromus, p. 447. + +_Definition._--#Tympanida# with two latticed horizontal rings, connected by +numerous parallel and vertical columellae; mitral and basal rings of equal +size. + +The genus _Lithotympanum_ has the form of a cylindrical drum, the two +fundamental faces of which (the mitral and basal gates) are closed by +lattice-work. Both horizontal rings are equal, whilst in the preceding +_Paratympanum_ the basal gate is larger than the mitral. It may be derived +from the latter by equalisation of these two rings, or directly from +_Dystympanium_ by fenestration of the basal ring. + + +1. _Lithotympanum tuberosum_, n. sp. (Pl. 83, fig. 1). + +Both lattice-plates slightly convex; the mitral plate with six larger +marginal pores and one central pore separated by numerous smaller pores; +the basal plate with seven large pores only (one central and six +peripheral). Surface and margin of the plates uneven, with roundish +prominent dimpled tubercles. Both rings connected by ten to twelve simple +cylindrical vertical columellae. + +_Dimensions._--Length of the shell 0.13, breadth 0.1. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +2. _Lithotympanum spinosum_, n. sp. + +Both lattice-plates flat, with numerous irregular roundish pores of +variable size. Surface thorny. Margin with numerous irregular spines, +directed upwards on the mitral, downwards on the basal plate. Both rings +connected by eight simple cylindrical vertical columellae. + +_Dimensions._--Length of the shell 0.12, breadth 0.08. + +_Habitat._--Western Tropical Pacific, Station 224, depth 1850 fathoms. + + + +Subfamily 3. DYSTYMPANIDA, Haeckel. + +_Definition._--#Tympanida# with fenestrated mitral ring and simple open +basal ring; both horizontal rings connected by numerous vertical or +divergent columellae. + + + +Genus 434. _Dystympanium_,[53] n. gen. + +_Definition._--#Tympanida# with two horizontal rings, connected by numerous +(six to eight or more) divergent columellae. The upper mitral ring is +smaller and latticed, the lower basal ring larger and open. + +{1007}The genus _Dystympanium_, representing a peculiar subfamily, differs +from all other Tympanida in the different shape of the two parallel +horizontal rings. The upper or mitral ring is closed by a lattice-plate (as +in _Paratympanum_), the lower or basal ring is simple and open (as in +_Eutympanium_). _Dystympanium_ may therefore be regarded as an intermediate +form between these two genera, and may perhaps be derived from +_Paratympanum_ by loss of the lower lattice-plate. + + +1. _Dystympanium dictyocha_, n. sp. (Pl. 94, figs. 15, 16). + +Basal ring circular, with eighteen to twenty short conical divergent +spines. Mitral ring about two-thirds as broad, hexagonal, with six +ascending spines on the six corners. The latter are connected with the +former by six simple, straight, obliquely descending columellae, about as +long as the diameter of the mitral ring. Mitral lattice-plate slightly +convex, with seven roundish pores (six peripheral pores around a central +pore). + +_Dimensions._--Diameter of the basal ring 0.09, mitral ring 0.06; length of +the columellae 0.05. + +_Habitat._--Tropical Atlantic, Station 338, depth 1990 fathoms. + + +2. _Dystympanium distephanus_, n. sp. + +Basal ring hexagonal, with six larger spines at the six corners, and +numerous smaller ones between them. Mitral ring half as broad as the basal +ring, also with six angular spines. The latter are connected with the +former by six divergent curved columellae, about as long as the diameter of +the basal ring. Mitral lattice-plate flat, with irregular roundish pores. + +_Dimensions._--Diameter of the basal ring 0.1, mitral ring 0.05; length of +the columellae 0.09. + +_Habitat._--Equatorial Atlantic, Station 347, depth 2250 fathoms. + + +3. _Dystympanium medusa_, n. sp. + +Basal ring circular, with eight larger and numerous smaller divergent +spines. Mitral ring two-thirds as broad as the basal ring, octagonal, with +eight conical ascending spines on the eight corners. The latter are +connected with the former by eight divergent, curved columellae, as long as +the diameter of the mitral ring. Mitral lattice-plate nearly hemispherical, +with nine circular pores (eight peripheral pores around one central pore). + +_Dimensions._--Diameter of the basal ring 0.12, mitral ring 0.08; length of +the columellae 0.09. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + + +Subfamily 4. EUTYMPANIDA, Haeckel. + +_Definition._--#Tympanida# with two simple horizontal rings, which are +connected by a variable number of vertical rods or columellae. Therefore +the shell exhibits a large simple mitral gate on the upper, and a large +simple basal gate on the lower side; between the two a variable number of +lateral gates. + + + +{1008}Genus 435. _Parastephanus_, Haeckel, 1881, Prodromus, p. 446. + +_Definition._--#Tympanida# with two simple horizontal rings, connected by +two vertical columellae. + +The genus _Parastephanus_ is the simplest among the Eutympanida, and +exhibits only two vertical rods or columellae, which connect the two +parallel horizontal rings. One of these latter must be regarded as the +mitral or superior ring, the other as the basal or inferior ring; whilst +the two parallel columellae, connecting both, are the remaining vertical +parts of the sagittal ring, the upper and lower parts of which are lost. By +loss of the latter _Parastephanus_ has probably been derived from +_Protympanium_. + + +1. _Parastephanus circularis_, n. sp. + +Two horizontal rings smooth, circular, of equal size, connected by two +curved smooth columellae, which are somewhat shorter than the diameter of +the rings. + +_Dimensions._--Diameter of the rings 0.08, length of the columellae 0.06. + +_Habitat._--Central Pacific, Station 263, depth 2650 fathoms. + + +2. _Parastephanus quadrispinus_, n. sp. (Pl. 93, fig. 21). + +Two horizontal rings smooth, elliptical or nearly circular, of equal size, +connected by two vertical, slightly curved columellae, which are about as +long as the radius of the rings. Each ring bears two simple lateral spines, +which in the mitral ring are curved downwards, in the basal ring upwards, +possibly the last remains of a reduced frontal ring. + +_Dimensions._--Diameter of the rings 0.09, length of the columellae 0.05. + +_Habitat._--North Pacific, Station 236, surface. + + +3. _Parastephanus asymmetricus_, n. sp. (Pl. 82, fig. 10). + +Two horizontal rings thorny, of equal size, irregularly ovate or nearly +semicircular, and of somewhat asymmetrical form. The two connecting +parallel columellae are straight, cylindrical, about as long as the +diameter of the rings. The peculiar asymmetry in the form of the rings +raises the possibility that the two columellae in this species are the +remaining parts of a frontal ring, and that the sagittal ring has +altogether disappeared. In this case the convex half of both rings would be +the ventral, the straight half the dorsal part. + +_Dimensions._--Diameter of the rings 0.1, length of the columellae 0.08. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +{1009}4. _Parastephanus dispar_, n. sp. + +Two horizontal rings elliptical, thorny, of different sizes, the basal ring +one and a half times as broad as the mitral ring. The two connecting +columellae are curved, somewhat longer than the diameter of the mitral +ring. + +_Dimensions._--Diameter of the basal ring 0.09, mitral 0.06; length of the +columellae 0.07. + +_Habitat._--South Pacific, Station 300, depth 1375 fathoms. + + + +Genus 436. _Prismatium_,[54] Haeckel, 1862, Monogr. d. Radiol., p. 270. + +_Definition._--#Tympanida# with two simple horizontal rings, connected by +three vertical columellae. + +The genus _Prismatium_ was hitherto the only known form of the Tympanida, +and the only species described in 1862 in my Monograph was _Prismatium +tripleurum_ (_loc. cit._, p. 270, pl. iv. fig. 6). A new species from the +Challenger collection (Pl. 93, fig. 22), _Prismatium tripodium_, explains +the true structure of this remarkable genus. The skeleton is composed of +nine siliceous rods, corresponding to the edges of a trilateral prism. Six +of these are horizontal, and enclose the two parallel triangular horizontal +gates, the superior of which is formed by the mitral or coryphal, and the +inferior by the basal or cortinar ring. The three other rods are vertical +and nearly parallel, and connect (as lateral edges of the prism) the +corresponding corners of the two parallel horizontal triangles. Two of +these vertical columellae, together with the two horizontal parallel rods +connecting them, represent the complete frontal ring, whilst the third +vertical columella is the posterior half of the sagittal ring, the other +parts of which are lost. + + +1. _Prismatium tripodium_, n. sp. (Pl. 93, fig. 22). + +Mitral ring triangular, somewhat smaller than the triangular basal ring, +both connected at the corners by three vertical, slightly curved +columellae. From the six corners arise six radial spines of different size +and form; the two paired spines of the mitral ring are simple and very +small, whilst those of the basal ring are three times as long and bear a +lateral branch. The odd spine of the third corner is on both rings larger, +and distinguished by some thorns. This difference seems to indicate that +these two odd spines correspond to the apical horn and the caudal foot of +_Cortina_, and the columella between them is the rest of the reduced +sagittal ring. In this case the quadrangular vertical ring, which is +composed of the two paired columellae and the two connecting horizontal +rods, would be probably the frontal ring. + +_Dimensions._--Length of the shell 0.09, breadth 0.07. + +_Habitat._--Equatorial Atlantic, Station 347, surface. + + +{1010}2. _Prismatium tripleurum_, Haeckel. + + _Prismatium tripleurum,_ Haeckel, 1862, Monogr. d. Radiol., p. 270, Taf. + iv. fig. 6. + + _Acanthodesmia prismatium_, Haeckel, 1860, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, p. 799. + +Mitral and basal rings of equal size, equilateral triangular, both +connected at the corners by three vertical equal columellae. From the six +corners arise six short, equal, conical radial spines. The nine rods of the +shell correspond to the nine edges of a triangular equilateral prism. + +_Dimensions._--Length of the shell 0.044, breadth 0.032. + +_Habitat._--Mediterranean (Messina), surface. + + + +Genus 437. _Pseudocubus_,[55] n. gen. + +_Definition._--#Tympanida# with two simple horizontal rings of different +sizes, connected by four divergent columellae. + +The genus _Pseudocubus_ exhibits the characteristic form of an obelisk, or +a truncated four-sided pyramid. The four edges of this obelisk, or the four +"columellae," are the remaining parts of the two incomplete vertical rings; +two opposite edges are the dorsal and ventral rod of the sagittal ring; the +two alternate edges between these are the lateral rods of the frontal ring. +The two horizontal rings, which become connected by the four divergent +columellae, are the smaller mitral ring and the larger basal ring; both are +either square or nearly circular. + + +1. _Pseudocubus obeliscus_, n. sp. (Pl. 94, fig. 11). + +Mitral ring square, with circular gate and two divergent simple spines on +each corner. Basal ring twice as broad, square, with four convex sides and +one simple spine on each corner. Four columellae straight. All twelve rods +with three smooth edges. + +_Dimensions._--Breadth of the mitral ring 0.02, of the basal ring 0.05. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +2. _Pseudocubus octostylus_, n. sp. + +Mitral ring square, with one stout pyramidal spine on each corner. Basal +ring twice as broad, square, also with a single strong spine on each +corner. Four columellae straight. All twelve rods with three smooth edges. + +_Dimensions._--Breadth of the mitral ring 0.04, of the basal ring 0.08. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +{1011}3. _Pseudocubus hexapylus_, n. sp. (Pl. 94, fig. 12). + +Mitral ring circular, two-thirds as broad as the subcircular, or nearly +square, basal ring; both rings with a simple spine on the two sagittal +corners (dorsal and ventral), with a forked or branched larger spine on the +two lateral corners (right and left). All twelve rods more or less curved +and thorny. + +_Dimensions._--Breadth of the mitral ring 0.07, of the basal ring 0.1. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + + +Genus 438. _Lithocubus_,[56] Haeckel, 1881, Prodromus, p. 447. + +_Definition._--#Tympanida# with two simple horizontal rings of equal size, +connected by four parallel vertical columellae. + +The genus _Lithocubus_ is very remarkable for the regular cubical form of +the skeleton, which is composed of twelve siliceous rods, corresponding to +the twelve edges of a cube. Eight of these are horizontal, and enclose the +two parallel square horizontal gates, the superior mitral and the inferior +basal gate. The four other rods are vertical, parallel, and connect (as +lateral edges of the cube) the corresponding corners of the two horizontal +squares. Two opposite ones of these four vertical columellae are the +remaining halves of the incomplete sagittal ring; the two alternate are the +remaining halves of the incomplete frontal ring. The four lateral gates +between these four columellae are also square or rectangular, and either of +the same size as the two horizontal gates, or somewhat larger. _Lithocubus_ +may be derived from _Acrocubus_ by reduction of the coryphal and the basal +part of the primary sagittal ring, the only remaining parts of which are +the anterior and the posterior columellae. + + +1. _Lithocubus geometricus_, n. sp. (Pl. 94, fig. 13). + +The twelve rods, corresponding to the edges of the geometrical cube, are +straight and smooth; the eight corners provided with a small conical thorn. +The shell exhibits six equal square sides, and represents therefore exactly +the geometrical form of a cube. + +_Dimensions._--Diameter of the cube 0.05; thickness of the bars 0.008. + +_Habitat._--Tropical Pacific, Station 224, depth 1850 fathoms. + + +2. _Lithocubus octacanthus_, n. sp. + +The twelve rods of the cubical shell are slightly curved, convex, smooth, +as in the similar preceding species. It differs from that in the +development of eight slender radial spines, arising from the eight corners +of the geometrical cube, from two to three times as long as its diameter, +and lying opposite in pairs in its diagonals. + +_Dimensions._--Diameter of the cube 0.06; length of the spines 0.15. + +_Habitat._--North Atlantic, Canary Islands, surface. + + +{1012}3. _Lithocubus vinculatus_, Haeckel. + + _Acanthodesmia vinculata_, J. Mueller, 1856 (_partim_), Abhandl. d. k. + Akad. d. Wiss. Berlin, Taf. i. fig. 7 (not 4-6). + +The twelve rods of the cubical shell are curved and armed with scattered, +simple, short spines. The figure 7 of Johannes Mueller (_loc. cit._) +corresponds exactly to the Mediterranean form observed by me at Portofino, +and is quite different from his true _Acanthodesmia vinculata_ (_loc. +cit._, figs. 4-6), so that I have no doubt he did observe these two +different species (compare above, p. 975). + +_Dimensions._--Diameter of the cube 0.07; length of the spines 0.02. + +_Habitat._--Mediterranean (Nice, Portofino). + + +4. _Lithocubus astragalus_, n. sp. (Pl. 82, fig. 12). + +The twelve rods of the cubical shell are stout and slightly curved, armed +with numerous, simple, and irregularly branched spines. Eight larger +spines, branched like a deer's antler, arise from the eight corners of the +cube. + +_Dimensions._--Diameter of the cube 0.1 to 0.12; length of the corner +spines 0.05 to 0.08. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +Genus 439. _Circotympanum_,[57] n. gen. + +_Definition._--#Tympanida# with two simple different horizontal rings, +connected by numerous (six to eight or more) divergent columellae. + +The genus _Circotympanum_ comprises those Tympanida in which two simple +horizontal rings of different size (an upper smaller "mitral ring," and a +lower larger "basal ring") are connected by a variable number of divergent +rods or columellae (at least six or eight). _Circotympanum_ is probably +derived from _Tympaniscus_ or _Tympanidium_ by partial reduction of the +sagittal ring, the upper (apical) and lower (basal) part of which is lost. +The geometrical fundamental form is a truncated pyramid with six to eight +or more edges. + + +1. _Circotympanum hexagonium_, n. sp. + +Mitral and basal ring hexagonal, the latter twice as broad as the former, +each with a simple small spine on the six corners. Six columellae nearly +straight, as long as the radius of the basal ring. All rods with three +prominent edges. + +_Dimensions._--Breadth of the mitral ring 0.06, of the basal ring 0.11. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +{1013}2. _Circotympanum octogonium_, n. sp. (Pl. 94, fig. 17). + +Mitral and basal rings octagonal, the latter one and a half times as broad +as the former. Eight columellae slightly curved, thorny. The mitral ring +bears on each corner a short ascending spine, the basal ring a larger, +thorny, obliquely descending spine, which has some recurved thorns on the +upper edge. All rods more or less thorny. + +_Dimensions._--Breadth of the mitral ring 0.06, of the basal ring 0.09. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +3. _Circotympanum decagonium_, n. sp. + +Mitral and basal rings circular, the latter nearly twice as broad as the +former, both armed with scattered irregular thorns. Ten columellae smooth, +curved. + +_Dimensions._--Breadth of the mitral ring 0.07, of the basal ring 0.12. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + + +Genus 440. _Eutympanium_,[58] Haeckel, 1881, Prodromus, p. 447. + +_Definition._--#Tympanida# with two simple equal horizontal rings, +connected by numerous (six to eight or more) parallel and vertical +columellae. + +The genus _Eutympanium_ contains those Tympanida in which the drum-shaped +shell is composed of two simple, parallel and equal horizontal rings, and +numerous vertical and parallel rods or columellae connecting them. The +number of the latter is at least six or eight. Two opposite of these must +be regarded as remaining vertical parts of the sagittal ring, two others as +parts of the frontal ring, whilst the other columellae (between the former +and the latter) are secondary and intercalated. Therefore _Eutympanium_ may +be derived from _Tympanidium_ by reduction and loss of the apical and basal +parts of the sagittal ring. + + +1. _Eutympanium musicantum_, n. sp. (Pl. 83, fig. 2). + +Eight parallel and vertical columellae, simple, straight and smooth. Both +horizontal rings equal, circular, each armed with eight to twelve short +conical thorns. + +_Dimensions._--Height of the shell 0.09, breadth 0.07. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +{1014}2. _Eutympanium octonarium_, n. sp. + +Eight vertical columellae slightly curved, thorny. Both horizontal rings +equal, octagonal, each armed with eight large, irregularly-branched spines, +which on the mitral ring are directed obliquely upwards, on the basal ring +downwards. + +_Dimensions._--Height of the shell 0.12, breadth 0.1. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +3. _Eutympanium coronarium_, n. sp. + +Eight thorny columellae, obliquely descending and curved like a bow, +divergent in the upper part, convergent in the lower. Basal ring circular, +mitral ring octagonal. Both horizontal rings armed with eight stout thorny +spines, which on the mitral ring are smaller and directed obliquely +upwards, on the basal ring larger and directed downwards, each with a +recurved hook. + +_Dimensions._--Height of the shell 0.08, breadth 0.06. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +4. _Eutympanium militare_, n. sp. (Pl. 82, fig. 11). + +Ten parallel and vertical columellae straight and smooth, cylindrical. Both +horizontal rings equal, circular, armed with numerous short conical spines, +divergent in all directions. Ten to twenty spines on each ring larger than +the others. + +_Dimensions._--Height of the shell 0.1, breadth, 0.08. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +5. _Eutympanium dodecarium_, n. sp. + +Twelve vertical columellae, slightly curved, smooth. Mitral and basal rings +circular, both horizontal rings armed with twelve stout, +irregularly-branched spines, which are prolongations of the columellae, and +on the mitral ring directed upwards, on the basal ring downwards. + +_Dimensions._--Height of the shell 0.13, breadth 0.1. + +_Habitat._--South Pacific, Station 300, depth 1375 fathoms. + + +{1015}---- + + +Order VI. CYRTELLARIA, Haeckel, 1881. + +_Definition_.--NASSELLARIA with a complete lattice-shell enveloping the +central capsule. + + + +Suborder I. SPYROIDEA, Haeckel. + + _Spyridina_, Ehrenberg (_pro parte_), 1847, Monatsber. d. k. preuss. + Akad. d. Wiss. Berlin, p. 54. + _Zygocyrtida_, Haeckel, 1862, Monogr. d. Radiol., p. 291. + _Zygocyrtida_, Buetschli, 1882, Zeitschr. f. wiss. Zool., vol. xxxvi. p. + 501. + _Acanthodesmida_, R. Hertwig, 1879, Organismus der Radiol., p. 68. + _Spyrida_ vel _Spyroidea_, Haeckel, 1881, Prodromus, p. 440. + +_Definition._--NASSELLARIA with a complete lattice-shell, exhibiting +constantly a bilocular cephalis with a sagittal constriction. + +The suborder #Spyroidea#, and the two following closely allied suborders, +#Botryodea# and #Cyrtoidea#, represent together that large group of +Radiolaria which I first described in my Monograph (1862, pp. 272, 280) as +the family Cyrtida, but afterwards as a separate order (or sublegion) under +the name #Cyrtellaria# (1883, Jena. Sitzungsber., Feb. 16, p. 18). This +group comprises all those MONOPYLEA or NASSELLARIA which possess a complete +lattice-shell, whilst the preceding #Plectellaria# never develop a perfect +fenestrated shell enveloping the central capsule. The #Spyroidea# differ +from the other #Cyrtellaria# (#Botryodea# and #Cyrtoidea#) in the bilocular +shape of the cephalis, which is bisected by the sagittal ring and a +corresponding longitudinal constriction into two symmetrical halves. + +The #Spyroidea# appear in the first system of Polycystina of Ehrenberg +(1847, _loc. cit._, pp. 53, 54) as the fourth of his seven families, under +the name Spyridina, with the following definition:--"Testae nucleo +destitutae (associatae et coalitae); cellulae binae clathratae, nucis forma +amplae, strictura longitudinali levius discretae." Ehrenberg united them +with his "Polycystina composita or SPUMELLARIA" and separated them from the +closely allied "Polycystina solitaria or NASSELLARIA." He distinguished +among them five genera, two of which have no external appendages +(_Dictyospyris_ and _Pleurospyris_), whilst the other three possess spiny +or lamellar appendages (_Ceratospyris_, _Cladospyris_, and _Petalospyris_). +These five genera and the accompanying definitions were also repeated in +the same terms in the last system of Ehrenberg (1875, _loc. cit._, p. 157). +In my Monograph (1862, pp. 280, 291) the #Spyroidea# are enumerated as a +{1016}subfamily of the Cyrtida, under the name Zygocyrtida, with the +following definition:--"Lattice-shell divided by an annular sagittal +longitudinal constriction into two neighbouring equal joints or chambers." +I adopted at that time the above five genera of Ehrenberg, only eight +species of which were known. + +Richard Hertwig gave in 1879 the first accurate description of the central +capsule of the #Spyroidea#, and demonstrated that they possess the same +characteristic structure of the capsule, with a porochora and a podoconus, +that is common to all MONOPYLEA. He separated the Zygocyrtida from the +other Cyrtida, and united them with the #Stephoidea# (_Lithocircus_) in the +family Acanthodesmida. In my Prodromus (1881, p. 449) I adopted that +division and put the "Spyrida or #Spyroidea#" as a separate family between +the #Cyrtoidea# and #Stephoidea#. I there gave the following +definition:--"_Monopylaria gemina_, testa silicea clathrata gemina, cameris +binis juxta compositis, annulo verticali sagittali contiguis, capsula +centrali a testa inclusa. Promorpha dipleura vel bilaterali, dextro et +sinistro antimero symmetricis, plano sagittali annuloque separatis. Polum +superiorem axis verticalis vel principalis plerumque spina apicalis (vel +occipitalis) occupat, polum inferiorem ostium clathratum (poris tribus aut +quatuor aut pluribus) et spina caudalis (posterior). Ad dextram et +sinistram duae spinae laterales distant. Ab hac forma tripoda (Monocyrtida +triradiata acuta cum annulo mediano) diversae Spyridum formae derivandae +sunt." I there divided the Spyrida into seven subfamilies and forty-eight +genera. Buetschli in 1882 published accurate researches on the Zygocyrtida +in his Beitraege zur Kenntniss der Radiolarien-Skelete, insbesondere der +der Cyrtida (Zeitschr. f. wiss. Zool., vol. xxxvi. p. 501, Taf. xxxii.). He +gave a very exact anatomical description of the skeleton of several fossil +#Spyroidea# of Barbados, and pointed out their close affinity to the +Acanthodesmida on the one hand, and to the Cyrtida on the other. Regarding +their phylogenetical relation, he supposed that the Zygocyrtida have +descended from the Acanthodesmida (our #Stephoidea#) and are the ancestors +of all other Cyrtida. The best part of this valuable paper of Buetschli is +his exact description of the sagittal ring and its apophyses, producing the +basal plate; and the general conception thus derived of the essential parts +of the skeleton in all MONOPYLEA, bearing a sagittal ring. But his general +conclusions were partly erroneous, since the fossil #Spyroidea# and +#Cyrtoidea# of Barbados, upon which they were founded, contain only the +minority of genera of the large group; and many important and typical forms +remained unknown to him. + +The numerous new genera discovered in the rich collection of the +Challenger, and mainly in the wonderful Radiolarian ooze of the Central +Pacific (Stations 263 to 274) throw a new light upon the complicated +affinities of the whole group, and manifest a far greater richness in +developmental variations and admirable morphological productions than +Buetschli could suppose. The following description, however, must remain +very incomplete, since the exact and thorough study of all individual +forms, in the same manner as {1017}Buetschli had done in the case of a +small number of species, would require several years. I can therefore only +give the basis of further researches. + +In the majority of #Spyroidea# the three essential elements of the +Nassellarian skeleton are easily recognisable, viz.:--A, the vertical +sagittal ring of the #Stephoidea#; B, the basal tripod of the #Plectoidea#, +and C, the latticed cephalis of the #Cyrtellaria#. These three elements are +constantly so combined that the primary sagittal ring bisects the cavity of +the lattice-shell and produces an external, longitudinal, more or less +distinct constriction, separating the lateral inflated halves of the +bilocular cephalis; while the three divergent feet of the basal tripod +descend from the cortinar or basal plate of the cephalis. The number of the +feet is often augmented; they are rarely wanting (probably reduced). The +sagittal ring is constantly present, though its relation to the shell-wall +exhibits many modifications. The bilocular form of the fenestrated +cephalis, with its sagittal constriction, is characteristic of all true +#Spyroidea#, and separates them from the #Botryodea# (with multilobate +cephalis) on the one hand, and from the #Cyrtoidea# (with simple cephalis) +on the other. There are, however, some intermediate forms between these +three suborders of #Cyrtellaria#, which show a direct transition to one +another. Almost constantly the length of the three dimensive axes in the +cephalis of the #Spyroidea# is so different that the lateral or frontal +axis is the longest, the sagittal or dorso-ventral axis the shortest, and +the principal or longitudinal axis intermediate between them. As in all +dipleuric or bilaterally symmetrical forms, the two poles of the frontal +axis are equal, whilst the two poles of the sagittal and of the principal +axis are more or less different. In only a few forms of #Spyroidea# these +differences are difficult to make out; usually the dorsal side is +distinctly different from the ventral, and the apical side from the basal. +A perfect knowledge of the dipleuric shell requires therefore accurate +observation from all six sides. + +The suborder of #Spyroidea# is here divided into four different families. +In the first and original family, the Zygospyrida, the shell is represented +by the bilocular cephalis only. The second family, Tholospyrida, is +distinguished by a fenestrated cupola or galea, a hemispherical or conical +dome, arising from the upper or coryphal face of the cephalis. In the third +family, Phormospyrida, a thorax is developed, or a fenestrated basal +chamber, arising from the lower or basal face of the cephalis. The fourth +family, Androspyrida, combines the characters of the second and the third +family, a galea arising from the upper and a thorax from the lower face of +the cephalis. + +The bilocular cephalis, as the most important and constant part of the +skeleton in all #Spyroidea#, requires a further general consideration. Its +lattice-work, very variable in the numerous species, is usually more or +less different on the six sides of the nut-shaped shell. Its most important +part is the horizontal basal plate or lower face, and the sagittal ring +arising from it in the vertical median plane. This part of the shell +corresponds exactly to the skeleton of the Semantida, and exhibits the same +modifications {1018}as in that family; it is therefore probable that the +majority of the #Spyroidea# (if not the whole group) have been derived +directly from the Semantida by further development of network from the +fenestrated ring of _Clathrocircus_. Whilst in this latter Semantid the two +lateral sides of the central capsule remain naked, in the #Spyroidea# they +become enclosed and covered by lattice-work, which arises on the right and +left from the ring. In some forms, however, as in the _Ceratospyris +acuminata_ of Hertwig, and in my Perispyrida, the frontal ring also of the +Coronida and the mitral ring of the Tympanida appear as the initial parts +of a complete latticed cephalis. + +The basal plate of the cephalis, or the "cortinar plate," the +"Basal-Scheibe" of Buetschli, has constantly, according to this author, two +pairs of pores, an anterior smaller pair of jugular pores (the pores I of +Buetschli) and a posterior larger pair of cardinal pores (the pores II in +his description) (compare Pl. 95, figs. 3, 6). This applies to the majority +of #Spyroidea#, but by no means to the whole group. We find basal plates +with two pores only (Pl. 95, fig. 1), with three pores (figs. 2, 5), with +six pores (figs. 4, 7), with nine pores (Pl. 87, fig. 2), &c. The forms +with two basal pores may be derived directly from _Semantis_ (Pl. 92, figs. +1, 2); the common forms with four pores from _Semantrum_ (figs. 3-5); the +rarer forms with six pores from _Semantidium_ (figs. 6, 7); and the forms +with three pores from _Cortiniscus_, &c. In this as well as in other +respects the variety of different forms and of developmental variations is +far greater than Buetschli (1882, _loc. cit._) supposed. The bars between +the pores of the basal plate possess the same value and the same names as +in the Semantida (compare above, p. 954). + +The coryphal plate of the cephalis, its upper or apical lattice-plate, does +not exhibit such important differences as the opposite basal plate, is far +less variable, and is usually pierced by numerous, smaller pores. Some +larger pores lie, often in pairs, on the right and left side of the +sagittal constriction, and have in some groups a regular form and +disposition. Either in the middle of the coryphal plate, or (usually) +nearer to its dorsal margin, there arises in majority of #Spyroidea# an +apical horn, directed either vertically or more or less obliquely +backwards. In many #Spyroidea# three horns are developed in the coryphal +plate, the odd middle apical horn and two paired frontal or lateral horns +arising on each side of the latter and directed more forwards (Pl. 84, +figs. 9-12). Sometimes the apical horn disappears, while the two frontal +horns remain (Pl. 95, fig. 12). + +The anterior or ventral plate of the cephalis (the "Hinterseite" of +Buetschli), and the posterior or dorsal side (the "Vorderseite" of that +author), exhibit in the majority of #Spyroidea# more or less marked +differences in the number, form, and disposition of their pores, which +require a far more accurate description than is here possible. Usually the +sagittal constriction of these two plates, produced by the primary vertical +ring, is deeper and sharper in the middle of the ventral than in that of +the dorsal plate. On both sides of the ring there appear in each plate +usually two or three pairs of larger pores, whilst numerous smaller pores +are situated towards the lateral sides. We may {1019}distinguish the large +pores of the ventral plate as facial pores (upper orbital, middle nasal, +and lower maxillary pores), and the opposite large pores of the dorsal +plate as occipital pores (upper epoccipital, middle mesoccipital, and lower +suboccipital pores). A closer comparison of these pores, and of the +separating bars in the numerous #Spyroidea#, may show a regularity of +development similar to that offered by the homologies of the parts in the +skeleton of the Echinodermata, or of the bones in the skull of the +Vertebrata. + +The two convex lateral plates of the cephalis, or the right and left sides, +both symmetrically equal, do not exhibit the same regularity in the shape, +number, and disposition of the pores that the four other sides do. Usually +their pores are much smaller and more numerous. In very few forms only a +distinct frontal ring is visible (corresponding to that of the Coronida), +and in this case the lateral pores are sometimes disposed symmetrically on +both sides of this ring. These #Spyroidea# may have arisen directly from +corresponding forms of Coronida. + +The sagittal ring (or the primary vertical ring) inherited from the +Stephanida and Semantida, shows in the #Spyroidea# great variety in its +form and in its relation to the cephalis. These variations are far greater +than Buetschli (1882, _loc. cit._) supposed. We may distinguish the +following six principal cases:--A. The ring lies completely in the wall of +the cephalis, and causes a deep sagittal constriction in it. In this case +the lower part or basal segment of the ring separates the basal pores into +pairs; its anterior part or ventral rod the facial pores; its upper part or +coryphal rod the apical pores; and its posterior part or dorsal rod the +occipital pores. No part of the ring is free in the shell-cavity. B. The +greater part of the ring lies enclosed in the shell-wall; only its dorsal +rod arises free in the shell-cavity and ascends vertically or obliquely to +the apex, where it is usually prolonged into the apical horn. This seems to +be the most common case. C. The coryphal and the basal part of the ring lie +enclosed in the shell-wall, with its dorsal and ventral rod free in the +shell-cavity; the dorsal rod ascends vertically to the apex, the ventral +rod obliquely upwards to the upper part of the facial plate (the nasal or +orbital region). This case, regarded by Buetschli as the usual one, is far +less common than he supposed. D. The greater part of the ring lies free in +the shell-cavity, its basal rod only is enclosed in the shell-wall, and +separates the right from the left group of the cortinar pores. This case +seems to be rarer than the preceding. E. The whole ring lies free in the +shell-cavity, and is connected with the sagittal constriction of the +shell-wall by numerous short radial beams. The distance of the shell-wall +from the enclosed ring is usually least on the basal rod, and greatest on +the dorsal rod. F. The whole ring lies free in the shell-cavity (as in the +preceding case), and is connected by numerous short radial beams with a +secondary larger, concentric sagittal ring, which is developed in the +longitudinal constriction of the shell-wall. + +{1020}Comparing these six principal cases, in respect of the relation of +the primary sagittal ring to the cephalis of the #Spyroidea#, we may +suppose that they represent together a continuous phylogenetical series of +which the first (A) is the original, and the last (F) the latest case; and +that the true cause of the various changes is a successive separation of +the ring, which becomes more and more free and independent from the +lattice-plate of the cephalis. Since the intimate study of the structure of +the cephalis in many #Spyroidea# is very difficult, it requires further +accurate observations (from all six sides of the shell). There are also +some other more difficult complications of its structure, which cannot be +solved without exact study and extended comparison. + +Of peculiar importance for the differentiation of the numerous genera of +the #Spyroidea# are the basal feet or the descending and diverging +apophyses, which are developed from the base of their cephalis. In general +they exhibit the same typical shape which we find in the #Plectellaria# as +well as in the #Cyrtoidea#, and which we regard therefore as an important +common character of the majority of NASSELLARIA. We may therefore +distinguish here also the three primary, and the other ones as secondary +feet. The three primary feet, or the "cortinar feet," are the same that we +found in the Plagonida and Plectanida, in _Cortina_ and _Cortiniscus_ among +the #Stephoidea#, and in the majority of #Cyrtoidea#. They also reappear in +the same characteristic disposition and connection with the basal plate of +the cephalis, in the majority of #Spyroidea#. The odd caudal foot (_c_) is +the lower prolongation of the dorsal rod of the sagittal ring, which is +prolonged upwards into the apical horn. The two paired pectoral feet, +however (_p'_, _p''_), are the descending prolongations of the coracal rods +(_e_) which separate the jugular pores (_i_) from the cardinal pores (_k_) +of the cortinar plate (compare Pl. 95, figs. 2-6). + +The three cortinar feet are nearly equally developed in the majority of +#Spyroidea# (compare Pls. 84, 89). But often the odd caudal foot exhibits a +different shape from that of the two paired pectoral feet, and in many +genera of the group it becomes more or less rudimentary. It has quite +disappeared in the subfamily Dipospyrida (Pl. 85); here the two pectoral +feet only are developed (often excessively), and are usually opposite in +the frontal plane. Such dipodal forms, very common in the #Spyroidea#, are +never found in the #Cyrtoidea#. + +The secondary feet, which we contrast with the three primary feet as later +productions, exhibit great variations in number and development. Very +frequently three interradial secondary feet become developed, alternating +with the three primary cortinar or perradial feet, and opposed to them in +pairs (Pl. 95, figs. 7, 8). In these hexapodal #Spyroidea# (or Hexaspyrida) +an odd anterior or sternal foot (_z_) is opposite to the odd caudal foot, +and two paired posterior or tergal feet (_t'_, _t''_) to the two pectoral +feet. When the sternal foot becomes rudimentary or lost, pentapodal forms +arise (Pentaspyrida, Pl. 95, figs. 9-11), and when the two odd feet (caudal +and sternal) disappear, tetrapodal forms arise with two pairs of feet +(Therospyrida, Pl. 89, figs. 5, 6). The latter differ from {1021}those +quadrupedal forms in which two opposite sagittal feet (the caudal and +sternal) alternate in the form of a cross with two paired lateral or +pectoral feet (Tetraspyrida, Pl. 53, figs. 19, 20). In many #Spyroidea# the +number of basal feet is greatly increased, and they form a regular radial +corona around the basal plate, like a circle of tentacles (Polyspyrida, Pl. +87). In this latter case the feet are usually flat and lamellar, whilst in +the other groups they exhibit a very variable form, as is seen in Pls. +83-89. + +The _Central Capsule_ of the #Spyroidea# has been accurately observed in +only a few genera, and requires a further exact examination regarding the +different modifications which occur in their different families. It is very +probable that these will agree with the well known modifications in the +corresponding groups of #Cyrtoidea#. The characteristic Monopylean +structure of the capsule (with porochora and podoconus) was first described +by Richard Hertwig in his _Ceratospyris acuminata_ (_loc. cit._, p. 72, +taf. vii. fig. 2). I found the same afterwards in many other forms. In the +Zygospyrida and Tholospyrida the central capsule seems to be usually +bilobate (bisected by the sagittal ring), and enclosed in the two chambers +of the cephalis. The two lobes of the capsule (right and left) are equal +and connected by a smaller middle part, which contains the transverse +elliptical nucleus and is enclosed by the sagittal ring; often each lobe +contains a large oil-globule. In some forms, however, three or four lobes +(sometimes perhaps more) are developed, which pierce the cortinar pores of +the basal plate and depend freely between the basal feet (Pl. 53, fig. 19). +In the Phormospyrida and Androspyrida the formation of such basal lobes +seems to be more frequent; they are here enclosed by the thorax. Usually +each lobe contains a large oil-globule. In _Nephrospyris_ (Pl. 90) and in +some similar genera the central capsule is violin-shaped, deeply bisected +by the sagittal ring; in each of the two lobes a series of oil-vesicles is +developed at both poles of the transverse axis (figs. 7, 10); the nucleus, +a transverse cylindrical body, is placed in the latter. In the periphery of +the voluminous calymma of this singular genus a large number of globular +cells are developed (figs. 7, 10), probably symbiotic xanthellae. In some +forms of _Nephrospyris_ these xanthellae are enclosed by a peculiar +inflated girdle, developed in the periphery of the kidney-shaped skeleton +(Pl. 90, figs. 1, 4-6). + +_Synopsis of the Families of_ #Spyroidea#. + + {Cephalis without galea + Shell without thorax; no second { (or apical cupola), 1. ZYGOSPYRIDA. + shell-joint, developed from { + the base of the cephalis. {Cephalis with a galea + { (or apical cupola), 2. THOLOSPYRIDA. + + {Cephalis without galea + Shell with a thorax, or a { (or apical cupola), 3. PHORMOSPYRIDA. + second shell-joint, developed { + from the base of the cephalis.{Cephalis with a galea + { (or apical cupola), 4. ANDROSPYRIDA. + + + +{1022}Family LII. #ZYGOSPYRIDA#, n. fam. (Pls. 84-87). + +_Definition._--#Spyroidea# without galea and thorax; the shell consisting +of the bilocular cephalis only and its apophyses. + +The family Zygospyrida is by far the richest among the four families of +#Spyroidea#, the number of genera in the whole suborder amounting to +forty-five, in the former to twenty-eight; and the number of species in the +latter to two hundred and thirty-seven, in the former to one hundred and +seventy-two. The number of individuals also found in many species of +Zygospyrida is far greater than in any species of the three other families. +The shell of the Zygospyrida is represented by the bilocular cephalis only, +and never develops a galea (as in the Tholospyrida) nor a thorax (as in the +Phormospyrida and Androspyrida). The three latter families have therefore +been derived from the former as their common ancestral group. + +The Zygospyrida are very similar and nearly related to the Monocyrtida, and +in both groups the cephalis alone represents the whole shell. Therefore in +1882, Buetschli, in the paper mentioned above (p. 1016), maintained the +opinion, that these two groups were identical. But there is this important +difference between them, that in the Zygospyrida (as in all #Spyroidea#) +the cephalis is bilocular, with a sagittal constriction, separating the +right and left chambers. In the Monocyrtida, however (as in all +#Cyrtoidea#), the cephalis is unilocular, forming a quite simple chamber +without sagittal constriction. Correspondingly the primary sagittal ring in +all Zygospyrida is well preserved and usually complete, while in the +Monocyrtida it is never complete, and often quite absent. Another +difference is indicated by the form of the central capsule, which in the +Zygospyrida is usually bilobed, and more developed in the frontal axis, +whilst in the Monocyrtida it is commonly ovate, and more developed in the +principal axis. + +The important questions of the origin and phylogenetical relation of these +two similar groups of NASSELLARIA form a very complicated and difficult +problem, and we do not at present possess the means of solving it. It may +be that a part of the Monocyrtida has been derived from the Zygospyrida (as +Buetschli erroneously supposes for all), but the contrary is also possible. +A third possibility is the independent origin of both groups from the +Semantida. But we shall see afterwards, in the description of the +Monocyrtida, that a great part of this group may with greater probability +be derived from the #Plectoidea# than from the #Stephoidea#, and that +another part of them has probably been derived quite independently from the +Nassellida. Regarding the complicated relations of these similar groups, +mentioned above (pp. 892-894), it seems hopeless here to discuss further +their difficult affinities; but in any case it seems useful or even +necessary to separate the Monocyrtida from the Zygospyrida. + +{1023}The cephalis of the Zygospyrida possesses all the characteristic +features which we have described above as belonging to the #Spyroidea# in +general (p. 1017), and a survey of the Pls. 84-87 exhibits the most +important modifications of its shape (compare also Pl. 95, figs. 1-13). +Therefore we may avoid useless repetitions by referring to the description +given above. We will only point out that the bilocular character of the +cephalis (in opposition to the simple cephalis of the Monocyrtida) in the +majority of Zygospyrida is apparent on the first view, and that it is +always demonstrated by an accurate examination of the sagittal ring and its +relation to the longitudinal constriction of the cephalis (compare p. +1019). The basal plate or cortinar plate exhibits usually four typical +pores (two smaller jugular, _i_, and two larger cardinal, _k_), but this is +by no means a general rule, as Buetschli thought; moreover, instead of four +cortinar pores, there are frequently found three or six or some other +numbers (compare above, p. 1018). + +The top of the cephalis in the majority of Zygospyrida bears an apical +horn, as an upper prolongation of the dorsal rod of the sagittal ring; it +is often of unusual size and shape (Pl. 85, figs. 5-11; Pl. 95, fig. 8, +&c.). In several genera two lateral or frontal horns are developed on both +sides of the former (Pl. 84, figs. 9-12; Pl. 86, figs. 5-13). Sometimes +these two alone are present, while the original apical horn is lost by +reduction (Pl. 95, fig. 12). In other genera the apical face bears no +horns; probably they are lost by reduction. + +The greatest variety of forms is produced in the Zygospyrida by the +different number, disposition, and shape of the feet, or the basal +apophyses arising from the base of the cephalis. Regarding these remarkable +differences, we may distinguish eight subfamilies. The common ancestral +group of all are probably the Tripospyrida, which possess the three typical +basal feet of _Cortina_ and _Cortiniscus_, an odd caudal and two paired +pectoral feet (Pl. 84). From these may be derived the Dipospyrida (Pl. 85) +by loss of the caudal foot, the Tetraspyrida by development of an odd +sternal foot (Pl. 53, figs. 7, 8, 19), and the Hexaspyrida by development +of three secondary interradial between the three primary perradial feet. +The Pentaspyrida may have been derived from the latter by loss of the +sternal foot (Pl. 95, figs. 9-11), and the Therospyrida by loss of the two +sagittal feet (Pl. 89, figs. 5, 6). The Polyspyrida bear numerous (seven to +twelve or more, often twenty to thirty) basal feet, forming a corona around +the cortinar plate (Pl. 87); they may have been derived from the +Tripospyrida or Hexaspyrida by further multiplication of the feet. Finally, +the Circospyrida exhibit no feet at all (Pl. 89, figs. 7-12); they may be +derived either from one of the preceding groups by complete reduction and +loss of the basal apophyses, or directly from those Semantida which have no +feet (_Semantis_, _Semantrum_, _Clathrocircus_, &c.). + +{1024}_Synopsis of the Genera of Zygospyrida._ + + ------------------------------------------------------------------------- + I. Subfamily Tripospyrida. + Three basal feet. (One odd caudal and two paired pectoral.) + ------------------------------------------------------------------------- + Apex of the shell with one horn, 441. _Tripospyris_. + + Apex of the shell with three horns, 442. _Triceraspyris_. + + Apex of the shell without horns, 443. _Tristylospyris_. + + Apex with two large coryphal holes, right and + left, 444. _Cephalospyris_. + ------------------------------------------------------------------------- + II. Subfamily Dipospyrida. + Two basal lateral feet. (Originally the two pectoral feet.) + ------------------------------------------------------------------------- + Two feet free, not {Feet simple, }One horn, 445. _Dipospyris_. + grown together. { not branched, } + { without } + { lateral }No horn, 446. _Brachiospyris_. + { spines. } + { + {Feet branched }One horn, 447. _Dendrospyris_. + { like a tree. } + { + {Feet with a } + { series of }One horn, 448. _Dorcadospyris_. + { lateral } + { spines. } + + Two feet grown {Feet simple, 449. _Gamospyris_. + together and { + uniting to form a {Feet with a series of + ring. Apex with a { lateral spines, 450. _Stephanospyris_. + horn. + ------------------------------------------------------------------------- + III. Subfamily Tetraspyrida. Two sagittal and two lateral feet. + ------------------------------------------------------------------------- + {Apex with one horn, 451. _Tetraspyris_. + Feet simple, not branched. { + {Apex without a horn, 452. _Tessarospyris_. + ------------------------------------------------------------------------- + IV. Subfamily Hexaspyrida. Six basal feet. + ------------------------------------------------------------------------- + Two sagittal, two pectoral,{Apex with one horn, 453. _Hexaspyris_. + and two tergal feet. { + {Apex with three horns, 454. _Liriospyris_. + { + {Apex without a horn, 455. _Cantharospyris_. + ------------------------------------------------------------------------- + V. Subfamily Pentaspyrida. Five basal feet. + ------------------------------------------------------------------------- + One caudal, two pectoral, {Apex with one horn, 456. _Clathrospyris_. + and two tergal feet. { + {Apex with three horns, 457. _Aegospyris_. + { + {Apex without a horn, 458. _Pentaspyris_. + ------------------------------------------------------------------------- + VI. Subfamily Therospyrida. + Four paired lateral feet. (Two pectoral and two tergal.) + ------------------------------------------------------------------------- + Apex with one horn, 459. _Zygospyris_. + + Apex with three horns (one apical and two + frontal), 460. _Elaphospyris_. + + Apex with two lateral or frontal horns, 461. _Taurospyris_. + + Apex without a horn, 462. _Therospyris_. + + VII. Subfamily Polyspyrida. Numerous (seven to twelve or more) + basal feet. + ----------- + Apex with one horn, 463. _Petalospyris_. + + Apex with three horns (one apical and two + frontal), 464. _Anthospyris_. + + Apex with numerous horns, 465. _Ceratospyris_. + + Apex without a horn, 466. _Gorgospyris_. + + VIII. Subfamily Circospyrida. No basal feet. + -------------------------------------------- + Apex with one horn, 467. _Circospyris_. + + Apex without a horn, 468. _Dictyospyris_. + + + +{1025}Subfamily 1. TRIPOSPYRIDA, Haeckel, 1881, Prodromus, p. 441. + +_Definition._--#Zygospyrida# tripoda, with three descending basal feet (the +same as in _Cortina_, an odd posterior or caudal foot and two paired +anterior or pectoral feet). + + + +Genus 441. _Tripospyris_,[59] Haeckel, 1881, Prodromus, p. 441. + +_Definition._--#Zygospyrida# with three basal feet and one apical horn. + +The genus _Tripospyris_ (Pl. 84, figs. 1-7) is in the large group of +#Spyroidea# probably the most original and typical form, from which, as a +common ancestral form, all other genera of this polymorphous suborder may +be derived. The shell is usually shaped like a nut or thorax, and exhibits +two paired lateral chambers, which are separated by a distinct sagittal +ring and a slighter or deeper sagittal constriction. The dorsal rod of the +ring is prolonged at the upper pole into an ascending apical horn, at the +lower pole into a descending caudal foot, whilst two paired pectoral or +lateral feet arise from the anterior pole of the basal rod. These three +divergent basal feet and the apical horn are the same four typical radial +spines which we have encountered already in _Plagoniscus_ (Plagonida), in +_Plectaniscus_ (Plectanida), in _Cortina_ (Stephanida), and in +_Cortiniscus_ (Semantida). Compare above, p. 891. From all these +#Plectellaria#, _Tripospyris_ differs in the development of a complete +bilocular lattice-shell, having the characters of the true #Spyroidea#. The +numerous species of this genus may be placed in different subgenera, +according to the different number of collar pores or cortinar pores in the +basal plate (two, three, four, six, or more). These differences are very +important, however difficult to make out; the following system therefore is +a provisional one, and requires further accurate observations. + + + +Subgenus 1. _Tripospyrantha_, Haeckel. + +_Definition._--Basal plate with two large pores only (the primary jugular +pores of _Semantis_). + + +1. _Tripospyris cortina_, n. sp. (Pl. 95, fig. 1). + +Shell ovate, smooth, about as long as broad, with slight ovate sagittal +stricture, and broad primary ring in its wall. Basal plate with two large +kidney-shaped collar pores only (cardinal pores). Facial and occipital +plates each with two pairs of large annular pores, and ten to twelve pairs +of small lateral pores. Apical horn and the three basal feet of equal +length, one and a half times as long as the shell, three-sided prismatic, +straight, divergent. + +_Dimensions._--Shell 0.08 long, 0.09 broad; horn and feet 0.15 long. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +{1026}2. _Tripospyris cortiniscus_, n. sp. (Pl. 84, fig. 6). + +Shell ovate, smooth, one and a third times as long as broad, with sharp +ovate sagittal stricture and broad primary ring. Basal plate with two large +cardinal pores only. Occipital plate with two pairs of very large pores; +facial plate and lateral sides with numerous smaller irregular roundish +pores. Apical horn small, conical, curved, half as long as the three basal +feet, which are club-shaped and three-edged, with thinner bases and half as +long as the shell, strongly divergent. + +_Dimensions._--Shell 0.12 long, 0.09 broad; horn 0.03 long, feet 0.06 long. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +3. _Tripospyris semantis_, n. sp. (Pl. 84, figs. 2, 3). + +Shell subspherical, smooth, somewhat broader than long, with slight +sagittal stricture and subcircular parietal primary ring. Basal plate with +two large semicircular cardinal pores. Facial and occipital plate each with +two pairs of large annular pores and an odd large subapical pore; lateral +sides with very numerous small roundish pores. Apical horn and caudal foot +club-shaped, half as long as the shell, angular, simple; the two pectoral +feet somewhat longer, nearly vertical, and at the distal end with a small +incision, nearly forked. + +_Dimensions._--Shell 0.1 long, 0.12 broad; horn and feet 0.05 to 0.07 long. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +4. _Tripospyris diomma_, n. sp. (Pl. 84, fig. 5). + +Shell thorax-shaped, smooth, twice as broad as long, with deep sagittal +stricture, two vaulted ovate bosoms and smaller ovate internal primary +ring. Basal plate with two large ovate cardinal pores. Facial plate with +three pairs, occipital plate with four pairs of large annular pores; the +other lattice-work loose, with small and numerous irregular polygonal +pores. Apical horn and caudal feet slender and thin, curved, shorter than +half the shell; two pectoral feet also small, widely divergent, more or +less curved, deeply forked. + +_Dimensions._--Shell 0.1 long, 0.16 broad; horn and feet 0.2 to 0.25 long. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + + +Subgenus 2. _Tripospyrella_, Haeckel. + +_Definition._--Basal plate with three large collar pores (two paired +posterior cardinal pores, and an odd anterior sternal pore). + + +5. _Tripospyris triomma_, Haeckel. + + _Ceratospyris triomma_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 66, Taf. xxi. fig. 3. + +Shell subspherical, tuberculate, with slight sagittal stricture and +circular internal ring. Basal plate with three large pores, which are +sometimes (but not in every specimen) surrounded by a {1027}circle of very +small pores. The other lattice-work with numerous small roundish pores. +Apical horn small, oblique, about as long as the shell. Three feet very +large, cylindrical, curved, widely divergent, four to five times as long as +the shell. (In Ehrenberg's description the caudal foot is erroneously +described as "frontal spine"; its figure exhibits the basal plate.) + +_Dimensions._--Shell 0.07 to 0.09 diameter; horn 0.06 long, feet 0.3 to 0.4 +long. + +_Habitat._--Fossil in Tertiary rocks of Barbados. + + +6. _Tripospyris conifera_, n. sp. (Pl. 84, figs. 7, 7_a_). + +Shell nearly hemispherical, papillate, with slight sagittal stricture and +semicircular internal ring. Basal plate with three large pores (sometimes, +as in the figured specimen, with some small accessory peripheral pores). +The other lattice-work with subregular circular pores. Apical horn shorter +than the three basal feet, but of similar form, like an elegant ovate +dimpled cone, spinulate, with a smooth spindle-shaped pedicle, about as +long as the shell. + +_Dimensions._--Shell 0.08 long, 0.1 broad; horn 0.06 long, feet 0.08 long. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +7. _Tripospyris triplecta_, n. sp. (Pl. 95, fig. 2). + +Shell thorax-shaped, spiny, with deep sagittal stricture and semicircular +internal ring. Basal plate with three large collar pores. Facial plate with +four pairs, occipital plate with three pairs of large annular pores; the +other pores small, subregular, circular. Apical horn and the feet slender, +three-sided pyramidal, about as long as the shell. + +_Dimensions._--Shell 0.1 long, 0.11 broad; horn and feet 0.1 to 0.15 broad. + +_Habitat._--Mediterranean, Corfu (Haeckel), surface. + + + +Subgenus 3. _Tripospyrissa_, Haeckel. + +_Definition._--Basal plate with two pairs of collar pores (two larger +posterior cardinal pores and two smaller anterior jugular pores). + + +8. _Tripospyris semantrum_, n. sp. (Pl. 95, fig. 3). + +Shell thorax-shaped, thorny, with deep sagittal stricture and subcircular +ring. Basal plate with four large collar pores (two smaller ovate jugular, +and two larger pentagonal cardinal pores). Facial and occipital plates also +each with two pairs of large annular pores; lateral sides with smaller +irregular polygonal pores. Apical horn and the three feet slender, +prismatic, divergent, longer than the shell. + +_Dimensions._--Shell 0.07 long, 0.08 broad; horn and feet 0.11 to 0.13 +long. + +_Habitat._--South Atlantic, Cape of Good Hope (Wilhelm Bleek), surface. + + +{1028}9. _Tripospyris capitata_, n. sp. (Pl. 84, fig. 1). + +Shell subspherical, spiny, with slight sagittal stricture and ovate +internal ring. Basal plate with four large collar pores. Facial plate with +three pairs and occipital plate with two pairs of large roundish annular +pores; lateral lattice with smaller irregular pores. Apical horn and the +three feet subcylindrical, about half as long as the shell, straight, +divergent, with a spherical, spinulate knob at the distal end. + +_Dimensions._--Shell 0.09 long, 0.1 broad; horn and feet 0.05 to 0.06 long. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +10. _Tripospyris clavata_, Haeckel. + + _Ceratospyris clavata_, Buetschli, 1882, Zeitschr. f. wiss. Zool., vol. + xxxvi. p. 539, Taf. xxxii. fig. 13, _a-c_. + +Shell subspherical, compressed, rough, with slight sagittal stricture and +ovate internal primary ring. Basal plate with four large collar pores (fig. +13_a_, _loc. cit._). The other lattice-work with irregular small roundish +pores. Apical horn and the three feet short and thick, scarcely half as +long as the shell, with a roundish spinulate knob at the distal end. + +_Dimensions._--Length of the shell 0.07 long, 0.08 broad; horn and feet +0.02 to 0.03 long. + +_Habitat._--Fossil in Barbados. + + +11. _Tripospyris tessaromma_, n. sp. + +Shell nearly cubical, spiny, with deep sagittal stricture and subcircular +ring. Basal plate with four large collar pores. Facial and occipital plates +each also with two pairs of large square annular pores; lateral pores +irregular polygonal. Apical horn half as long as the feet, which are three +times the length of the shell, cylindrical, slightly curved. + +_Dimensions._--Shell 0.1 long, 0.12 broad; horn 0.15 long, feet 0.3 long. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms. + + + +Subgenus 4. _Tripospyromma_, Haeckel. + +_Definition._--Basal plate with six or more collar pores. Commonly two +small anterior jugular pores, two large middle cardinal pores, and two +small posterior cervical pores; sometimes several small accessory collar +pores. + + +12. _Tripospyris hexomma_, n. sp. (Pl. 95, fig. 4). + +Shell thorax-shaped, tuberculate, with deep sagittal stricture and +semicircular internal primary ring. Basal plate with three pairs of pores. +Facial plate with two pairs, occipital plate with four pairs of large +annular pores. Lateral pores smaller, irregular, polygonal. Apical horn and +caudal foot half as long as the shell and as the two pectoral feet; all +four spines cylindrical, two to three times as long as the shell, slightly +curved. + +_Dimensions._--Shell 0.1 long, 0.12 broad; horn and feet 0.2 to 0.4 long. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +{1029}13. _Tripospyris semantidium_, n. sp. + +Shell nut-shaped, thorny, with sharp sagittal stricture and subcircular +ring. Basal plate with three pairs of large pores. Facial and occipital +plates each with three pairs of large squarish pores. Lateral pores small +and numerous, irregular roundish. Apical horn half as long as the shell and +the three feet; all four spines straight, cylindrical, with thickened +club-shaped end. + +_Dimensions._--Shell 0.12 long, 0.13 broad; horn 0.06 long, feet 0.15. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + +14. _Tripospyris eucolpos_, n. sp. (Pl. 84, fig. 4). + +Shell thorax-shaped, smooth, with two vaulted bosoms, separated by a deep +sagittal stricture and an internal primary ring. Basal plate constricted, +with three pairs of collar pores. The other lattice-work with subregular +circular pores. Apical horn and the three feet shorter than the shell, +straight, divergent; their inner half thinner, cylindrical, smooth, their +outer half an ovate dimpled cone. + +_Dimensions._--Shell 0.1 long, 0.13 broad; horn and feet 0.06 long. + +_Habitat._--Indian Ocean, Cocos Islands (Rabbe), surface. + + +15. _Tripospyris tribrachiata_, Haeckel. + + _Cladospyris tribrachiata_, Ehrenberg, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 68, Taf. xxi. fig. 8. + +Shell subspherical, smooth, with slight sagittal stricture and numerous, +very small circular pores. Basal plate with numerous small pores. Apical +horn and the three divergent feet very large and stout, straight, +three-sided prismatic, with dentate edges, two to three times as long as +the shell. + +_Dimensions._--Shell diameter 0.05; horn and feet 0.1 to 0.15 long. + +_Habitat._--Fossil in Barbados. + + +16. _Tripospyris furcata_, n. sp. (Pl. 83, fig. 11). + +Shell nut-shaped, smooth, with deep sagittal stricture and broad ring. +Basal plate with three pairs of small pores. Facial and occipital plates +each with a pair of very large holes. Apical horn and caudal foot simple +conical, two pectoral feet forked or irregularly branched. + +_Dimensions._--Shell 0.08 long, 0.12 broad; horn and feet 0.05 long. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +Genus 442. _Triceraspyris_,[60] Haeckel, 1881, Prodromus, p. 441. + +_Definition._--#Zygospyrida# with three basal feet and three coryphal +horns. + +The genus _Triceraspyris_ has arisen from the preceding ancestral +_Tripospyris_ by the development of two paired frontal horns, so that the +shell here bears six appendages, {1030}three superior or coryphal spines +and three inferior or basal spines; two of these are odd and dorsal (the +apical horn and the caudal foot), the four others are paired and ventral +(the frontal horns and the pectoral feet). The numerous species of this +genus may be divided into three subgenera, according to the simple or +branched shape of the ascending horns and of the descending feet. + + + +Subgenus 1. _Triospyris_, Haeckel, 1881, Prodromus, p. 441. + +_Definition._--Horns and feet simple, not branched nor forked. + + +1. _Triceraspyris tripodiscus_, n. sp. + +Shell nut-shaped, tuberculate, with deep sagittal stricture. Pores +irregular roundish, two pairs of larger pores on each side of the ring. +Basal plate with three large pores. Horns and feet slender cylindrical, +straight, divergent; three horns about as long as the shell, three feet +twice as long. + +_Dimensions._--Shell 0.06 long, 0.08 broad; horn 0.05 long, feet 0.1. + +_Habitat._--Central Pacific, Stations 270 to 274, depth 2350 to 2925 +fathoms. + + +2. _Triceraspyris cortiniscus_, n. sp. + +Shell subspherical, smooth, with slight sagittal stricture. Pores small and +numerous, subregular roundish. Basal plate with two large pores (?). Apical +horn conical, short, half as long as the shell and the two lateral horns, +which are curved outwards. All three feet equal, cylindrical, strongly +curved and divergent, twice to three times as long as the shell. + +_Dimensions._--Shell 0.07 long, 0.08 broad; horn 0.04 to 0.08 long, feet +0.15 to 0.2 long. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +3. _Triceraspyris didiceros_, Haeckel. + + _Ceratospyris didiceros_, Ehrenberg, 1875, Abhandl. d. Akad. d. Wiss. + Berlin, p. 66, Taf. xxi. fig. 6. + +Shell nut-shaped, thorny, with superficial sagittal stricture. Pores large, +irregular roundish. Basal plate with four larger pores. Apical horn and +caudal foot small, conical, shorter than half the shell. The two frontal +horns longer, slender conical. The two pectoral feet very large, +cylindrical, nearly parallel, vertical, slightly curved, twice to three +times as long as the shell. + +_Dimensions._--Shell 0.07 long, 0.09 broad; two sagittal spines 0.02 long, +two lateral horns 0.04 long, two lateral feet 0.15 to 0.25 long. + +_Habitat._--Fossil in Barbados. + + + +Subgenus 2. _Triospyrium_, Haeckel. + +_Definition._--Horns simple, not branched; feet forked or branched. + + +{1031}4. _Triceraspyris furcata_, Haeckel. + + _Ceratospyris furcata_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 66, Taf. xx. fig. 8. + +Shell nut-shaped, tuberculate, with slight sagittal stricture. Pores +numerous, irregular roundish. Basal plate with four large pores. Three +horns small, conical, shorter than half the shell. Three feet large, +cylindrical, curved, about twice as long as the shell, forked at the distal +end. + +_Dimensions._--Shell 0.07 long, 0.08 broad; horns 0.02 long, feet 0.1 to +0.12 long. + +_Habitat._--Fossil in Barbados. + + +5. _Triceraspyris giraffa_, n. sp. (Pl. 84, fig. 11). + +Shell nut-shaped, mammillate, with slight sagittal stricture. Pores +numerous, subregular circular. Basal plate with nine pores (three larger +central and three alternate pairs of smaller peripheral, as in Pl. 87, fig. +2). Three horns equal, straight, divergent, shorter than the shell, in the +basal half cylindrical, in the distal half spindle-shaped. Three feet +cylindrical, twice as long as the shell, nearly parallel, vertical, at the +distal end divergent, with a recurved branch near the base. + +_Dimensions._--Shell 0.08 long, 0.1 broad; horns 0.05 to 0.07 long, feet +0.16 long. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +6. _Triceraspyris gazella_, n. sp. (Pl. 84, fig. 9). + +Shell nut-shaped, tuberculate, with sharp sagittal stricture. Pores large, +irregular roundish; two or three pairs of larger pores on each side of the +ring. Basal plate with three large triangular pores. Three horns simple, +about as long as the shell, the apical straight, the two frontal elegantly +curved. Three feet somewhat longer, slender, curved, with a recurved branch +near the base, repeatedly forked at the distal end. + +_Dimensions._--Shell 0.06 long, 0.09 broad; horn 0.05 long, feet 0.08 long. + +_Habitat._--Indian Ocean (Cocos Islands), surface (Rabbe). + + +7. _Triceraspyris corallorrhiza_, n. sp. (Pl. 84, fig. 12). + +Shell nut-shaped, spiny, with deep sagittal stricture. Pores irregular +polygonal or roundish. Basal plate with two large semicircular pores. Three +horns slender, simple, about half as long as the shell. Three feet of the +same length, slender, divergent, irregularly branched like coral. + +_Dimensions._--Shell 0.06 long, 0.09 broad; horn and feet 0.03 to 0.05 +long. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +8. _Triceraspyris maniculata_, n. sp. + +Shell subspherical, smooth, without external sagittal stricture. Pores +subregular circular. Basal plate with four large pores (?). Three horns +simple, straight, divergent, spindle-shaped, half {1032}as long as the +shell. Caudal foot of the same form, twice as long. Two pectoral feet +cylindrical, curved, twice as long as the shell, palmate, divided at the +distal end into five short fingers. + +_Dimensions._--Shell 0.08 diameter; horns 0.04 long; lateral feet 0.12 +long. + +_Habitat._--North Pacific, Station 241, depth 2300 fathoms. + + +9. _Triceraspyris longicornis_, n. sp. + +Shell nut-shaped, papillate, with deep sagittal stricture. Pores irregular +roundish. Basal plate with six pores (?). Apical horn short, conical, two +frontal horns very large, curved, widely divergent, longer than the shell. +Three feet of about the same length, irregularly branched. + +_Dimensions._--Shell 0.08 long, 0.12 broad; lateral horns and feet 0.15 to +0.2 long. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms. + + + +Subgenus 3. _Triospyridium_, Haeckel. + +_Definition._--Horns and feet forked or branched. + + +10. _Triceraspyris damaecornis_, n. sp. + +Shell nut-shaped, smooth, compressed, with broad sagittal ring. Pores +irregular roundish; one pair of very large pores on each side of the ring. +Basal plate with four large collar pores. Three horns and three feet short, +divergent, slightly curved, about half as long as the shell, irregularly +branched. (In general form very similar to _Elaphospyris damaecornis_, Pl. +84, fig. 10, with which I formerly confounded it.) + +_Dimensions._--Shell 0.08 long, 0.12 broad; horns and feet 0.04 long. + +_Habitat._--South Pacific, Station 295, depth 1500 fathoms. + + +11. _Triceraspyris arborescens_, n. sp. + +Shell subspherical, with deep sagittal stricture. Pores irregular roundish; +three pairs of larger pores on both sides of the ring. Basal plate with two +large collar pores. Three horns about half as long as the shell, with few +irregular terminal branches. (Beginning of a cupola.) Three feet strong, +cylindrical, twice as long as the shell, richly branched, arborescent. + +_Dimensions._--Shell 0.09 long, 0.1 broad; horns 0.05 long, feet 0.2 long. + +_Habitat._--Indian Ocean (Madagascar), Rabbe, surface. + + + +Genus 443. _Tristylospyris_,[61] Haeckel, 1881, Prodromus, p. 441. + +_Definition._--#Zygospyrida# with three basal feet, without apical horn. + +The genus _Tristylospyris_ exhibits in general the same structure as the +typical genus _Tripospyris_, its ancestral form. It differs from the latter +in the absence of the apical {1033}horn, which is completely reduced, and +may therefore be regarded as the simplest prototype of all tripodal +Cyrtellaria without a horn. + + + +Subgenus 1. _Tristylospyrula_, Haeckel. + +_Definition._--Feet simple, not branched nor forked. + + +1. _Tristylospyris palmipes_, n. sp. (Pl. 84, fig. 14). + +Shell companulate, smooth, with slight sagittal stricture. Pores irregular +roundish, three pairs of larger annular pores on each side of the broad +ring. Basal plate with four large collar pores. Feet half as long as the +shell, slightly divergent, straight, prismatic, with a broad, hand-like, +radially striped plate at the distal end. + +_Dimensions._--Shell 0.1 long, 0.09 broad; feet 0.06 long. + +_Habitat._--Equatorial Atlantic, Station 347, depth 2250 fathoms. + + +2. _Tristylospyris scaphipes_, n. sp. (Pl. 84, fig. 13). + +Shell nut-shaped, smooth, with sharp sagittal stricture. Pores very small +and numerous, circular; two pairs of larger pores on both sides of the +ring. Basal plate with four large pores (?). Feet about half as long as the +shell, angular, shovel-shaped, straight, parallel, vertical. + +_Dimensions._--Shell 0.06 long, 0.08 broad; feet 0.04 long. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +3. _Tristylospyris clavipes_, n. sp. (Pl. 84, fig. 15). + +Shell nut-shaped, rough, with deep sagittal stricture. Pores small, +subregular circular. Basal plate with three large pores. Feet about as long +as the shell, slender, straight, divergent, with a spinulate knob at the +thickened distal end. + +_Dimensions._--Shell 0.06 long, 0.08 broad; feet 0.05 long. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +4. _Tristylospyris triceros_, Haeckel. + + _Ceratospyris triceros_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 66, Taf. xxi. fig. 5. + +Shell nut-shaped, tuberculate, without external sagittal stricture. Pores +circular, not numerous. Basal plate with four large collar pores. Feet +large, cylindrical, three to four times as long as the shell, strongly +curved and divergent. + +_Dimensions._--Shell 0.05 long, 0.07 broad; feet 0.15 to 0.2 long. + +_Habitat._--Fossil in Barbados. + + + +{1034}Subgenus 2. _Tristylospyrium_, Haeckel. + +_Definition._--Feet forked or branched. + + +5. _Tristylospyris furcata_, n. sp. + +Shell subspherical, rough, with slight sagittal stricture. Pores subregular +circular. Basal plate with three large collar pores. Feet cylindrical, +three to four times as long as the shell, strongly curved and divergent, at +the distal end forked, with two short (sometimes ramified) branches. + +_Dimensions._--Cephalis 0.08 long, 0.09 broad; feet 0.2 to 0.3 long. + +_Habitat._--South Atlantic (off Patagonia), Station 318, surface. + + +6. _Tristylospyris ramosa_, n. sp. (Pl. 52, fig. 23). + +Shell subspherical, tuberculate, with a prominent sagittal ring. Pores +irregular roundish. Basal plate with three large pores. Feet large, +straight, widely divergent, about twice as long as the shell, prismatic, +irregularly branched. (Compare the following species.) + +_Dimensions._--Shell 0.08 in diameter; feet 0.15 long. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +7. _Tristylospyris tripodiscium_, n. sp. (Pl. 52, fig. 22). + +Shell subovate, tuberculate, very similar to the preceding species. It +differs from this in the very different size of the irregular pores and the +greater breadth of the pedal branches. The basal plate in a complete +specimen (observed afterwards from the base) exhibited four large collar +pores of the usual form, whilst in the similar preceding species it had +three pores. In the similar _Tripodiscium sphaerocephalum_ (Pl. 52, fig. +21) the basal mouth is quite simple and open. + +_Dimensions._--Shell 0.09 long, 0.1 broad; feet 0.12 long. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + + +Genus 444. _Cephalospyris_,[62] Haeckel, 1881, Prodromus, p. 441 (_sensu +emend._). + +_Definition._--#Zygospyrida# with three basal feet and two large apical +openings or coryphal holes, one on each side of the ring-apex. No true +horns. + +The genus _Cephalospyris_ comprises some few Tripospyrida of very peculiar +shape, differing from all other Zygospyrida in the possession of two large +apical holes or coryphal apertures, lying on each side of a latticed +sagittal septum, which is formed by the upper part of the sagittal ring. +The sagittal stricture is deep, with a complete {1035}primary ring. The +vertical axis of the slender ovate shell is much greater than the +transverse. The network is very delicate, with very small and numerous +triangular or polygonal pores. The central capsule encloses peculiar +concrements (Pl. 96, fig. 28). + + +1. _Cephalospyris cancellata_, n. sp. (Pl. 83, fig. 10). + +Shell slender ovate, two and a half times as long as broad, with deep +sagittal stricture and complete ring. Network very delicate, with very +small and numerous, irregular polygonal pores. The two large apical holes +are separated by a latticed triangular sagittal septum, the apex of which +represents a rudimentary horn. Basal plate with two large collar holes. +Three feet slightly curved, divergent, about half as long as the breadth of +the shell; the caudal foot slender, much thinner than the two stout +pyramidal pectoral feet. + +_Dimensions._--Shell 0.32 long, 0.13 broad. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +2. _Cephalospyris ovata_, n. sp. + +Shell slender, ovate, twice as long as broad, with deep sagittal stricture +and complete ring. Network very delicate, with very small and numerous +triangular pores (on both poles intermingled with irregular polygonal +pores). The two large apical holes are separated by a latticed triangular +sagittal septum, the upper edge of which is concave and bears two +rudimentary horns. Basal plate with four large collar holes. Three feet +latticed, slightly curved, convergent, scarcely one-eighth as long as the +breadth of the shell. The central capsule filled up by concrements. + +_Dimensions._--Shell 0.32 long, 0.16 broad. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +3. _Cephalospyris triangulata_, n. sp. (Pl. 96, fig. 28). + +Shell ovate, one and a half times as long as broad, with deep sagittal +stricture and complete ring. Network very delicate and regular, with small +triangular pores of equal size. The two large apical holes are separated by +a latticed semilunar septum, the upper edge of which is concave, and bears +two rudimentary horns. Basal plate with three large collar holes (?). Three +feet latticed, conical, nearly parallel and vertical (the caudal curved), +about half as long as the breadth of the shell. The ovate central capsule +contains peculiar amyloidal concentric concrements. + +_Dimensions._--Shell 0.2 long, 0.14 broad. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + + +Subfamily 2. DIPOSPYRIDA, Haeckel, 1881, Prodromus, p. 441. + +_Definition._--#Zygospyrida# dipoda, with two descending lateral basal feet +(probably corresponding to the pectoral feet of _Cortina_). + + + +{1036}Genus 445. _Dipospyris_,[63] Haeckel, 1881, Prodromus, p. 441. + +_Definition._--#Zygospyrida# with two simple free basal feet and one apical +horn. + +The genus _Dipospyris_ and the following five genera represent together the +interesting subfamily of Dipospyrida, which always bear two opposite +lateral feet only. Therefore in this bipedal group the biradial or +bilateral type of the #Spyroidea# is particularly expressed. Such bipedal +forms never occur in the #Cyrtoidea#. The topographical relation of the two +lateral feet to the rods of the collar-plate, and to the cortinar pores +separated by these, leaves no doubt that they correspond to the pectoral +feet of _Cortina_ and _Tripospyris_, and therefore that the Dipospyrida +have originated from the Tripospyrida by loss of the caudal foot. +_Dipospyris_ is the simplest form of the Dipospyrida, with two simple free +feet. + + +1. _Dipospyris bipes_, n. sp. + +Shell thorax-shaped, smooth, with deep sagittal stricture, two vaulted +bosoms, and subregular circular pores. Basal plate with two large collar +pores only. Horn and feet equal, conical, straight, about as long as the +shell; the feet widely divergent. + +_Dimensions._--Shell 0.08 long, 0.12 broad; horn and feet 0.1 to 0.15 long. + +_Habitat._--Fossil in Barbados. + + +2. _Dipospyris mystax_, Haeckel. + + _Ceratospyris mystax_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 66, Taf. xx. fig. 6. + +Shell elliptical spinulate, with slight collar stricture and large +subregular circular pores. Basal plate with three pores (?) Horn small +conical, oblique, shorter than the shell. Feet slender conical, longer than +the shell, slightly curved, divergent. At the base of the columella, +between the two feet, a small rudiment of the last caudal foot is visible. + +_Dimensions._--Shell 0.06 long, 0.1 broad; horn 0.02, feet 0.12 long. + +_Habitat._--Fossil in Barbados. + + +3. _Dipospyris cubus_, n. sp. (Pl. 83, fig. 18). + +Shell box-shaped, subcubical, papillate, without external sagittal +stricture, with numerous subregular circular pores. Basal plate with three +very large collar pores, surrounded by a circle of smaller pores. Apical +horn short and thick, scarcely half as long as the shell. Feet of the same +form, longer than the shell, widely divergent. + +_Dimensions._--Shell 0.08 long, 0.11 broad; horn 0.03 long, feet 0.14 long. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +{1037}4. _Dipospyris chelifer_, n. sp. (Pl. 85, fig. 3). + +Shell elliptical, compressed, nodose, with deep sagittal stricture and +irregular roundish pores. Basal plate with three pores (?). Apical horn +stout, conical, twice to four times as long as the shell (often much longer +than in the figured specimen). Feet scarcely longer then the shell, +cylindrical, slightly curved towards one another. + +_Dimensions._--Shell 0.08 long, 0.12 broad; horn 0.2 to 0.3 long, feet 0.1 +to 0.15 long. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +5. _Dipospyris irregularis_, n. sp. Pl. 85, fig. 2. + +Shell subspherical, without external sagittal stricture, with small +circular pores. Basal plate with four pores. Apical horn small, conical, +shorter than the shell. Feet three to four times as long as the shell, +cylindrical, irregularly curved, very variable in size and form. + +_Dimensions._--Shell 0.08 long, 0.1 broad; horn 0.02 to 0.04 long, feet 0.2 +to 0.3 long. + +_Habitat._--Central Pacific, Stations 266 to 268, depth 2700 to 2900 +fathoms. + + +6. _Dipospyris sigmopodium_, n. sp. + +Shell violin-shaped, thorny, with deep sagittal stricture and irregular +roundish pores. Basal plate with four collar pores. Horn straight, conical, +about as long as the shell. Feet twice as long, cylindrical, markedly +divergent, S-shaped, curved. + +_Dimensions._--Shell 0.08 long, 0.12 broad; horn 0.06 long, feet 0.2 long. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms; also fossil +in Barbados. + + +7. _Dipospyris forcipata_, n. sp. (Pl. 85, fig. 1). + +Shell nut-shaped, tuberculate, with subregular circular pores. Basal plate +with four larger and a circle of six to ten smaller pores. Horn +cylindrical, straight, two to three times as long as the shell. Feet three +to five times as long as the shell, cylindrical, semicircular, with +convergent and crossed distal ends. (If these ends grow together, +_Gamospyris_ arises.) + +_Dimensions._--Shell 0.08 long, 0.11 broad; horn 0.15 to 0.2 long, feet 0.2 +to 0.4 long. + +_Habitat._--Central Pacific, Stations 263 to 268, depth 2600 to 3000 +fathoms. + + + +Genus 446. _Brachiospyris_,[64] Haeckel, 1881, Prodromus, p. 441. + +_Definition._--#Zygospyrida# with two simple free basal feet, without +apical horn. + +The genus _Brachiospyris_ differs from the preceding _Dipospyris_, its +ancestral form, only in the absence of the reduced apical horn, and +therefore bears to it a similar {1038}relation to that which the hornless +_Tristylospyris_, among the Tripospyrida, bears to the horned +_Tripospyris_. _Brachiospyris_ may therefore also be derived from +_Tristylospyris_ by loss of the caudal foot. + + +1. _Brachiospyris ocellata_, Haeckel. + + _Ceratospyris ocellata_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 66, Taf. xx. fig. 5. + +Shell nut-shaped, thorny, with slight sagittal stricture and irregular +roundish pores. Basal plate with four large and four alternate pairs of +smaller pores. Two feet cylindrical, straight, divergent, two to three +times as long as the shell. + +_Dimensions._--Shell 0.08 long, 0.11 broad; feet 0.2 to 0.3 long. + +_Habitat._--South Atlantic, Station 335, depth 1425 fathoms; also fossil in +Barbados. + + +2. _Brachiospyris diacantha_, n. sp. (Pl. 95, fig. 5). + + ? _Ceratospyris diacantha_, Ehrenberg, 1872, Monatsber. d. k. preuss. + Akad. d. Wiss. Berlin, p. 303. + +Shell nut-shaped, tuberculate, compressed in the sagittal axis, convex on +the frontal face, concave on the sagittal face, with a slight sagittal +stricture; with large irregular roundish pores. Basal plate with three very +large pores. Two feet cylindrical, curved, S-shaped, about twice as long as +the shell. + +_Dimensions._--Shell 0.06 long, 0.09 broad; feet 0.1 to 0.15 long. + +_Habitat._--Western Tropical Pacific (Philippine Sea), Station 206, depth +2100 fathoms. + + + +Genus 447. _Dendrospyris_,[65] Haeckel, 1881, Prodromus, p. 441. + +_Definition._--#Zygospyrida# with two free lateral feet, forked or branched +like a tree. Apex with a horn. + +The genus _Dendrospyris_ differs from its ancestral form _Dipospyris_ in +the ramification of the two large lateral feet, which descend from the base +of the shell, and are usually very large and stout, sometimes simply +forked. + + +1. _Dendrospyris stylophora_, Haeckel. + + _Ceratospyris stylophora_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 66, Taf. xx. fig. 10. + +Shell nut-shaped, thorny, with subregular circular pores. Basal plate with +four pores. Apical horn and the two divergent feet straight, cylindrical, +larger than the shell, forked at the distal end. {1039}(The size and number +of the fork-branches is variable; the horn is sometimes simple. In some +specimens a rudimentary remnant of the lost caudal foot is visible.) + +_Dimensions._--Shell 0.08 long, 0.09 broad; horn and feet 0.1 to 0.12 long. + +_Habitat._--Fossil in Barbados. + + +2. _Dendrospyris dirrhiza_, Haeckel. + + _Ceratospyris dirrhiza_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 66, Taf. xx. fig. 9. + +Shell nut-shaped, spiny, very similar to the preceding species. It differs +from that mainly in the growth of the cylindrical feet, which are not +straight and divergent, but more or less curved and convergent; their +distal ends are sometimes simply forked, sometimes repeatedly dichotomous. +The size and form of the apical horn are also very variable. + +_Dimensions._--Shell 0.06 long, 0.08 broad; horn and feet 0.07 to 0.09 +long. + +_Habitat._--Fossil in Barbados. + + +3. _Dendrospyris bibrachiata_, Haeckel. + + _Cladospyris bibrachiata_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 68, Taf. xxi. fig. 7. + +Shell nut-shaped, smooth, with sharp stricture and numerous very small +circular pores. Apical horn and the two feet very large and stout, +straight, prismatic, with irregular lateral branches on their edges, twice +to four times as long as the shell (The horn in the Ehrenberg's figure is +broken off.) This species is closely allied to _Tripospyris tribrachiata_. + +_Dimensions._--Shell 0.05 long, 0.06 broad; horn and feet 0.1 to 0.2 long. + +_Habitat._--Fossil in Barbados. + + +4. _Dendrospyris furcata_, n. sp. + +Shell subspherical, tuberculate, with irregularly roundish pores. Basal +plate with two large pores. Apical horn simple, conical, as long as the +shell. Feet cylindrical, twice as long, in the proximal half parallel, +vertical, in the distal half with two stout divergent equal fork-branches, +one of which is directed dorsally, the other ventrally. + +_Dimensions._--Shell 0.07 long, 0.08 broad; horn 0.06 long, feet 0.1 to +0.15 long. + +_Habitat._--Tropical Atlantic, Station 338, depth 1990 fathoms. + + +5. _Dendrospyris polyrrhiza_, n. sp. (Pl. 85, fig. 8). + +Shell subspherical, rough, with subregular circular pores. Basal plate with +three pores (?). Apical horn simple, conical, half as long as the shell. +Feet cylindrical twice to three times as long as the shell, semicircular, +with a strong conical tooth in the middle of their outer convex edge; their +distal ends convergent, divided into a bunch of numerous short irregular +branches. + +_Dimensions._--Shell 0.7 long, 0.08 broad; horn 0.03 long, feet 0.15 to +0.25 long. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +{1040}6. _Dendrospyris ramosa_, n. sp. + +Shell nut-shaped, spiny, with irregular roundish pores. Basal plate with +three pairs of pores. Apical horn cylindrical, spinulate, twice to three +times as long as the shell. Feet as long as the horn, S-shaped, widely +divergent, irregularly branched, with widely distant pointed branches. + +_Dimensions._--Shell 0.08 long, 0.12 broad; horn and feet 0.2 to 0.3 long. + +_Habitat._--North Atlantic, Station 353, depth 2965 fathoms. + + +7. _Dendrospyris arborescens_, n. sp. (Pl. 85, fig. 9). + +Shell nut-shaped, tuberculate, with subregular circular pores. Basal plate +with four central larger and ten to twelve peripheral smaller pores. Apical +horn cylindrical, twice as long as the shell, in the distal half spinulate +or tuberculate. Feet about three times as long as the shell, cylindrical, +nearly vertical, in the distal half irregularly branched, with dense +bunches of aggregated blunt branches. + +_Dimensions._--Shell 0.07 long, 0.09 broad; horn and feet 0.12 to 0.18 +long. + +_Habitat._--Equatorial Atlantic, Station 347, depth 2250 fathoms. + + + +Genus 448. _Dorcadospyris_,[66] Haeckel, 1881, Prodromus, p. 441. + +_Definition._--#Zygospyrida# with two free lateral feet armed with a series +of secondary spines. Apex with a horn. + +The genus _Dorcadospyris_ and the closely allied _Stephanospyris_ differ +from the other Dipospyrida in the development of a series of secondary +spines on the convex outer margin of the two large curved lateral feet, +which therefore appear semipinnate. In some species this peculiar armature +attains an extraordinary size, whilst the shell itself is very small, as in +_Dorcadospyris dinoceras_ (Pl. 85, fig. 4). + + +1. _Dorcadospyris dentata_, n. sp. (Pl. 85, fig. 6). + +Shell subspherical, tuberculate with small regular circular pores. Basal +plate with four larger pores. Apical horn three to four times as long as +the shell, slender conical, smooth. Feet more or less convexly curved +towards one another; the distal ends not crossed. In the convex edge of +each arm a series of five to ten smooth conical teeth, not longer than the +shell. This common species is very variable and often asymmetrical; the +figured specimen is an asymmetrical one, in which the two arms exhibit +different curves; in the normal form both arms have the same curve, now +more, now less convex. + +_Dimensions._--Shell 0.06 long, 0.08 broad; horn 0.2, feet 0.03 long. + +_Habitat._--Central Pacific, Stations 267 to 274, depth 2350 to 2925 +fathoms. + + +{1041}2. _Dorcadospyris antilope_, n. sp. (Pl. 85, fig. 5). + +Shell subspherical, tuberculate, with small regular circular pores. Basal +plate with four larger pores. Apical horn four to six times as long as the +shell, straight, cylindrical, smooth. Feet of the same length, crescentic +or nearly semicircular, with crossed distal ends. On the convex edge of +each foot a series of twelve to fifteen smooth conical teeth, partly longer +than the shell. (Very variable in size and curvature of the feet, and +number of their teeth.) + +_Dimensions._--Shell 0.09 long, 0.11 broad; horn and feet 0.4 to 0.6 long. + +_Habitat._--Central Pacific, Stations 270 to 274, depth 2350 to 2925 +fathoms. + + +3. _Dorcadospyris lunulata_, n. sp. + +Shell subspherical spinulate, nearly of the same shape as in the preceding +species, but with a short conical horn (scarcely as long as the shell); the +feet are much mere slender, crescentic, and bear twenty to thirty smaller +smooth conical teeth (shorter than the shell). The distal ends of the feet +are crossed. + +_Dimensions._--Shell 0.08 long, 0.09 broad; horn 0.06 long, feet 0.03 to +0.06 long. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +4. _Dorcadospyris decussata_, n. sp. (Pl. 85, fig. 7). + +Shell subspherical, smooth, very similar to that of the two preceding +species. Horn small conical, about as long as the shell. Feet more than +semicircular, more strongly curved than in any other species, each with +four to eight small conical teeth, shorter than the shell; distal ends +crossed. (In this species also, besides the normal symmetrical form, there +often occurs an asymmetrical form of the two feet; one of these frequent +anomalies is shown in fig. 7.) + +_Dimensions._--Shell 0.06 long, 0.08 broad; horn 0.05, feet 0.2 to 0.5 +long. + +_Habitat._--Central Pacific, Stations 265 to 268, depth 2700 to 2900 +fathoms. + + +5. _Dorcadospyris dinoceras_, n. sp. (Pl. 85, fig. 4). + +Shell subspherical, tuberculate, with subregular circular pores. Basal +plate with four larger central and eight to twelve smaller peripheral +pores. Horn about as long as the shell, in the basal half prismatic, +smooth, in the distal half ovate or strobiliform, spiny. Feet very large +and strongly curved, together nearly heart-shaped, four to six times as +long as the shell. Each foot bears on its outer convex side a series of +fifteen to twenty or more strong conical teeth, which are again spinulate, +perpendicular to the foot, and longer than the shell. + +_Dimensions._--Shell 0.08 long, 0.09 broad; horn 0.07 long, feet 0.3 to 0.5 +long. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + + +{1042}Genus 449. _Gamospyris_,[67] Haeckel, 1881, Prodromus, p. 441. + +_Definition._--#Zygospyrida# with two simple lateral feet, forming a ring +by union. + +The genus _Gamospyris_ and the similar _Stephanospyris_ differ from all +other #Spyroidea# in the possession of a large basal ring, placed in the +frontal plane of the shell. This ring has been produced by concrescence of +the distal ends of the two large curved lateral feet of _Dipospyris_. + + +1. _Gamospyris circulus_, n. sp. (Pl. 83, fig. 19). + +Shell subspherical, tuberculate, with subregular circular pores. Basal +plate with four larger collar pores. Apical horn pyramidal, about as long +as the shell. The connected feet form together a circular or nearly +circular smooth ring, the diameter of which is three to four times as great +as that of the shell. + +_Dimensions._--Shell 0.08 long, 0.09 broad; diameter of the arm-ring 0.25 +to 0.33. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +2. _Gamospyris annulus_, n. sp. + +Shell nut-shaped, tuberculate, with subregular circular pores. Basal plate +with four large central and a circle of eight to twelve small peripheral +pores. Apical horn conical, twice as long as the shell. The connected arms +form together an elliptical smooth ring, which is five times as long and +three times as broad as the shell. + +_Dimensions._--Shell 0.07 long, 0.09 broad; ring 0.33 long, 0.26 broad. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + + +Genus 450. _Stephanospyris_,[68] Haeckel, 1881, Prodromus, p. 441. + +_Definition._--#Zygospyrida# with two lateral feet bearing a series of +secondary spines and forming a ring by union. + +The genus _Stephanospyris_ exhibits the same peculiar armature of the +semipinnate lateral feet as its ancestral genus _Dorcadospyris_, but +differs from it in the concrescence of the distal ends of the feet, to form +a complete foot-ring. The former therefore bears to the latter the same +relation that _Gamospyris_ does to _Dipospyris_. + + +1. _Stephanospyris cordata_, n. sp. (Pl. 85, fig. 10). + +Shell subspherical, tuberculate, with small regular circular pores. Basal +plate with four larger pores. Apical horn cylindrical, three times as long +as the shell, with three to four verticils {1043}of teeth. The connected +feet form a heart-shaped ring, four times as long and three times as broad +as the shell. Each foot bears on the outer convex edge four to six stout +conical teeth, shorter than the shell. Distal ends crossed and prominent. + +_Dimensions._--Shell diameter 0.1; length of the arm-ring 0.4, breadth 0.3. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +2. _Stephanospyris verticillata_, n. sp. (Pl. 85, fig. 11). + +Shell nut-shaped, tuberculate, with subregular circular pores. Basal plate +with numerous small pores. Apical horn cylindrical, four to six times as +long as the shell, with six to ten verticils of teeth. The connected feet +form a circular ring, the diameter of which is four times as great as that +of the shell. Each foot bears ten to twelve conical teeth, about as long as +the shell. Distal ends not crossed and not prominent. + +_Dimensions._--Diameter of the shell 0.1, of the arm-ring 0.4. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +3. _Stephanospyris excellens_, n. sp. (Pl. 83, fig. 20). + +Shell subspherical, tuberculate, with regular circular pores. Basal plate +with numerous small pores. Apical horn cylindrical, twice as long as the +shell, with eight verticils of teeth. The connected feet form an ovate +ring, which is three times as long and two and a half times as broad as the +shell. Each foot bears eight conical spinulate teeth, about as long as the +shell. The crossed and prominent distal ends bear two parallel vertical +teeth. + +_Dimensions._--Diameter of the shell 0.1, of the arm-ring 0.2 to 0.3. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + + +Subfamily 3. TETRASPYRIDA, Haeckel, 1881, Prodromus, p. 442. + +_Definition._--#Zygospyrida# tetrapoda, with four descending basal feet, +two of which are opposite in the sagittal plane (an odd caudal and an odd +sternal foot), whilst the two others are paired lateral or pectoral feet. + + + +Genus 451. _Tetraspyris_,[69] Haeckel, 1881, Prodromus, p. 442. + +_Definition._--#Zygospyrida# with four basal feet crossed in pairs (two +sagittal and two lateral). Apex with a horn. + +The genus _Tetraspyris_ and the following closely allied _Tessarospyris_ +represent together the small subfamily of Tetraspyrida, characterised by +the possession of four descending basal feet, three of which correspond to +the three original feet of the {1044}ancestral genera _Cortina_ and +_Tripospyris_, whilst the fourth in an odd anterior or sternal foot, +produced by anterior prolongation of the basilar segment of the sagittal +ring. Here, therefore, two opposed feet lie in the sagittal plane (a caudal +and a sternal foot), whilst the two others are the paired lateral or +pectoral feet, as also in _Stephanium_ and _Stephaniscus_, p. 965. The +Tetraspyrida ought not to be confounded with the Therospyrida (sixth +subfamily), in which the four feet have another signification. + + + +Subgenus 1. _Tetrarrhabda_, Haeckel, 1881, p. 429. + +_Definition._--Feet simple, not branched nor forked. + + +1. _Tetraspyris stephanium_, n. sp. (Pl. 95, fig. 6). + +Shell nut-shaped, tuberculate, with deep sagittal stricture and small +roundish pores; three pairs of larger pores on each side of the ring. Basal +plate with four large collar pores. Apical horn stout conical, half as long +as the shell. Two pectoral feet somewhat longer than the two sagittal feet, +one and a half times as long as the shell. All four feet straight, +three-sided prismatic, strongly divergent. + +_Dimensions._--Shell 0.08 long, 0.12 broad; horn 0.04 long, feet 0.08 to +0.12 long. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +2. _Tetraspyris cubica_, n. sp. + +Shell nearly cubical, smooth, with slight sagittal stricture and small +polygonal pores; some larger pores on both sides of the ring. Basal plate +with four large collar pores. Apical horn and the four feet of equal size +and form, about as long as the shell, cylindrical in the basal, spindle +shaped in the distal half. + +_Dimensions._--Shell 0.09 diameter; horn and feet 0.1 long. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms; also fossil +in Barbados. + + + +Subgenus 2. _Tetracorethra_, Haeckel, 1831, Prodromus, p. 429. + +_Definition._--Feet branched or forked. + + +3. _Tetraspyris tetracorethra_, n. sp. (Pl. 53, figs. 19, 20). + + _Tetracorethra mirabilis_, Haeckel, 1881, Prodromus, p. 439, and Atlas, + loc. cit. + +Shell campanulate, tuberculate, with deep sagittal stricture and irregular +polygonal pores; two pairs of larger pores at the flattened occipital face +(fig. 20). Basal plate with four large collar pores. Apical horn very long, +thirty to forty times as long as the shell, slender three-sided prismatic, +straight, at the distal end irregularly branched, besom-shaped. Four basal +feet half as {1045}thick as the horn, eight to twelve times as long as the +shell, bristle-shaped, irregularly curved and branched, divergent, at the +distal end besom-shaped. Central capsule very large; the enclosed small +campanulate part sends out through the four collar pores four very long +club-shaped basal lobes, half as long as the feet; each lobe contains a +large oil-globule (fig. 19). + +_Dimensions._--Shell 0.036 diameter; horn 1 to 1.5 mm. long, feet 0.3 to +0.4 long. + +_Habitat._--Central Pacific, Station 270, surface. + + +4. _Tetraspyris calcarata_, n. sp. + +Shell campanulate, smooth, very similar to that of the preceding species, +but differing in the following characters:--the two inferior occipital +pores are four times (in the preceding twice) as large as the two superior; +the apical horn bears at its distal end only three simple branches; the +sternal foot is smaller than the three others, arises higher, is more +divergent and curved, and bears at its base a large horizontal conical +spur. + +_Dimensions._--Shell 0.035 diameter; horn 1 to 1.2 long, feet 0.2 to 0.3 +long. + +_Habitat._--Central Pacific, Station 266, surface. + + +5. _Tetraspyris scoparia_, n. sp. + +Shell campanulate, rough, very similar to the two preceding species, but +differing in the following characters:--the four occipital pores are of +nearly equal size; the apical horn is simple, not branched; the four feet +are forked near the base, so that apparently eight feet diverge, each in +the distal half richly branched, besom-shaped. + +_Dimensions._--Shell 0.038 diameter; horn 1 to 1.1 long, feet 0.4 to 0.5 +long. + +_Habitat._--Central Pacific, Station 268, surface. + + + +Genus 452. _Tessarospyris_,[70] Haeckel, 1881, Prodromus, p. 442. + +_Definition._--#Zygospyrida# with four basal feet crossed in pairs (two +sagittal and two lateral). Apex without horn. + +The genus _Tessarospyris_ differs from the preceding _Tetraspyris_, its +ancestral genus, in the absence of the apical horn, and therefore bears to +it the same relation that _Tristylospyris_ does to _Tripospyris_. + + +1. _Tessarospyris clathrobursa_, n. sp. (Pl. 53, fig. 8). + + _Clathrobursa dictyopus_, Haeckel, 1881, Prodromus, p. 439, and Atlas, + pl. liii. fig. 8. + +Shell nearly ovate, strongly compressed, smooth, one and a half times as +long as broad, with deep sagittal stricture in the basal half. Pores very +small and numerous, irregularly roundish. Basal plate with four very large +triangular holes, two larger (posterior) cardinal, and two smaller +(anterior) {1046}jugular pores; above the latter (on the frontal face) two +large mental pores. Two pectoral feet large, half as long as the shell, at +the base fenestrated, vertical, and parallel. Two sagittal feet much +smaller, nearly horizontal, pyramidal (the caudal larger than the sternal +foot). Two longitudinal pectoral ribs arise on the frontal face. + +_Dimensions._--Shell 0.21 long, 0.14 broad; lateral feet 0.1, sagittal feet +0.02. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +2. _Tessarospyris nuciformis_, n. sp. + +Shell nut-shaped, papillate, with deep sagittal stricture. Pores irregular +roundish, on both sides of the ring three to six times as large as on the +lateral sides. Basal plate with four large pores. Two pectoral feet +cylindrical curved, twice as long as the shell and as the two sagittal +feet; the caudal is much stronger than the sternal foot. + +_Dimensions._--Shell 0.06 long, 0.09 broad; lateral feet 0.1, sagittal feet +0.05 long. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + +3. _Tessarospyris seminulum_, Haeckel. + + _Petalospyris seminulum_, Stoehr, 1880, Palaeontogr., vol. xxvi. pl. iii. + fig. 12. + +Shell subspherical, smooth, with slight sagittal stricture and small +circular pores; some larger pores on both sides of the ring. Basal plate +with two large (lateral) pores only. Four feet nearly equal, short, +conical, divergent, scarcely one-fourth as long as the shell. + +_Dimensions._--Shell 0.06 long, 0.08 broad; feet 0.016 long. + +_Habitat._--Fossil in Tertiary rocks of Sicily (Grotte), Stoehr. + + + +Subfamily 4. HEXASPYRIDA, Haeckel. + +_Definition._--#Zygospyrida# hexapoda, with six descending basal feet; +three of these are primary (one odd caudal and two paired pectoral feet), +the other three are secondary, opposed diametrically to the former and +alternating with them (one odd sternal and two paired tergal feet). + + + +Genus 453. _Hexaspyris_,[71] n. gen. + +_Definition._--#Zygospyrida# with six basal feet and one apical horn. + +The genus _Hexaspyris_ and the two following closely allied genera +represent together the peculiar subfamily of Hexaspyrida, and differ from +the other Zygospyrida in the possession of six descending basal feet; three +of these are the three original, perradial, or primary basal feet of +_Cortina_, _Cortiniscus_, _Plagoniscus_, _Plectaniscus_, _Tripospyris_, +&c.; the other three, usually opposed to the former diametrically, are +{1047}secondary or interradial; an odd sternal foot (opposed to the odd +caudal) and two paired tergal feet (opposed to the two paired pectoral). + + + +Subgenus 1. _Hexaspyridium_, Haeckel. + +_Definition._--Feet simple, not branched nor forked. + + +1. _Hexaspyris alterna_, n. sp. + +Shell nut-shaped, smooth, with deep sagittal stricture and irregular +polygonal pores; on each side of the stricture two pairs of larger square +annular pores. Basal plate also with four larger collar pores. Apical horn +twice as long as the shell, conical. Three primary feet (the apical and the +two pectoral) slender, curved, as long as the horn; three secondary feet +(the sternal and the two tergal) are half as long as the former and more +highly inserted; all six feet strongly divergent, cylindrical, pointed. + +_Dimensions._--Shell 0.06 long, 0.09 broad; horn 0.15 long, feet 0.08 to +0.14 long. + +_Habitat._--Central Pacific, Stations 265 to 268, depth 2700 to 2900 +fathoms. + + +2. _Hexaspyris setigera_, Haeckel. + + _Ceratospyris setigera_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 66, Taf. xx. fig. 11. + + _Ceratospyris setigera_, Buetschli, 1882, Zeitschr. f. wiss. Zool., vol. + xxxvi. p. 539, Taf. xxxii. figs. 11_a_, 11_b_. + +Shell nut-shaped, tuberculate, with a complete internal sagittal ring and +numerous small circular pores. Basal plate with four larger central and a +circle of twelve to twenty smaller peripheral pores. Apical horn half as +long as the shell, bristle-shaped. Three primary feet longer and more +deeply inserted than the three secondary feet; all six feet strongly +divergent, bristle-shaped, shorter than the shell. + +_Dimensions._--Shell 0.06 long, 0.09 broad; horn 0.03 long; primary feet +0.05, secondary 0.02 long. + +_Habitat._--Fossil in Barbados. + + +3. _Hexaspyris buetschlii_, Haeckel. + + _Ceratospyris triomma_, Buetschli (_non_ Ehrenberg), 1882, Zeitschr. f. + wiss. Zool., vol. xxxvi. p. 539, Taf. xxxii. fig. 12, _a_, _b_. + +Shell nut-shaped, spinulate, with a complete internal sagittal ring and +subregular circular pores. Basal plate with twelve pores (four larger +central and eight smaller peripheral). Apical horn stout, oblique, as long +as the shell. Six feet of equal length, slightly divergent, nearly +vertical, slender, three to four times as long as the shell. + +_Dimensions._--Shell 0.05 long, 0.07 broad; horn 0.06, feet 0.15 to 0.2 +long. + +_Habitat._--Fossil in Barbados. + + +{1048}4. _Hexaspyris spinosa_, Haeckel. + + _Petalospyris spinosa_, Stoehr, 1880, Palaeontogr., vol. xxvi. p. 98, + Taf. iii. fig. 14. + +Shell subspherical, smooth, with slight sagittal stricture and irregular +polygonal pores; on each side of the stricture two pairs of larger pores. +Basal plate with two large pores only. Apical horn short, pyramidal, three +primary feet half as long as the shell and twice as long as the three +secondary feet. All six feet pyramidal, slightly divergent. + +_Dimensions._--Shell 0.05 long, 0.07 broad; horn 0.02, feet 0.02 to 0.04 +long. + +_Habitat._--Fossil in Tertiary rocks of Sicily (Grotte, Caltanisetta). + + +5. _Hexaspyris ophirensis_, Haeckel. + + _Petalospyris ophirensis_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 297, Taf. ix. fig. 24. + +Shell nut-shaped, with deep sagittal stricture and numerous irregular +roundish pores; two pairs of larger pores on each side of the stricture. +Apical horn short, curved. Six feet equal, divergent, straight, slender, +about as long as the shell. + +_Dimensions._--Shell 0.05 long, 0.1 broad; horn 0.01, feet 0.05 to 0.08 +long. + +_Habitat._--Indian Ocean (Zanzibar), depth 2200 fathoms, Pullen. + + + +Subgenus 2. _Hexacorethra_, Haeckel. + +_Definition._--Feet forked or branched. + + +6. _Hexaspyris hexacorethra_, n. sp. (Pl. 95, fig. 8). + + _Hexacorethra magica_, Haeckel, 1882, Manuscript. + +Shell campanulate, smooth, with sharp sagittal stricture and irregular +roundish pores. Basal plate with six larger collar pores. Apical horn very +long and thin, three-sided prismatic, straight, ten to twenty times as long +as the shell, branched at the distal end. Six feet thinner, bristle-shaped, +six to eight times as long as the shell, divergent, irregularly curved, in +the distal part branched, besom-shaped; the sternal foot at its base with a +large conical horizontal spur. + +_Dimensions._--Shell 0.034 diameter; horn 0.4 to 0.8 long, feet 0.2 to 0.3 +long. + +_Habitat._--Central Pacific, Station 265, surface. + + +7. _Hexaspyris articulata_, Haeckel. + + _Ceratospyris articulata_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 66, Taf. xx. fig. 4. + +Shell nut-shaped, tuberculate, with deep sagittal stricture and small +irregular roundish pores. Basal plate with six pores (?). Apical horn +conical, longer than the shell. Six feet very large, thick +{1049}cylindrical, divergent, three to four times as long as the shell, +with few irregular lateral branches (often much more developed than in +Ehrenberg's figure). + +_Dimensions._--Shell 0.036 long, 0.05 broad; horn 0.05, feet 0.1 to 0.15 +long. + +_Habitat._--Fossil in Barbados. + + + +Genus 454. _Liriospyris_,[72] Haeckel, 1881, Prodromus, p. 443. + +_Definition._--#Zygospyrida# with six basal feet and three coryphal horns. + +The genus _Liriospyris_ differs from the preceding _Hexaspyris_, its +ancestral form, in the possession of three coryphal horns (one odd apical +in the middle, and two paired frontal horns on each side of it); it +therefore bears to the latter the same relation that _Triceraspyris_ does +to _Tripospyris_. + + +1. _Liriospyris hexapoda_, n. sp. (Pl. 86, fig. 7). + +Shell subspherical, smooth, with slight sagittal stricture and irregular +roundish pores; two to three pairs of large annular pores on each side of +the stricture. Basal plate with four large collar pores. Three horns and +six feet nearly of the same size and of similar form, conical, divergent, +about one-third as long as the shell. + +_Dimensions._--Shell diameter 0.09 to 0.1; horns and feet 0.03 to 0.04 +long. + +_Habitat._--Central Pacific, Stations 265 to 268, depth 2700 to 2900 +fathoms. + + +2. _Liriospyris clathrata_, Haeckel. + + _Dictyospyris clathrus_, Ehrenberg, 1854, Mikrogeol., Taf. xxxvi. fig. + 25. + + _Dictyospyris clathrata_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 68, Taf. xix. fig. 7. + + _Dictyospyris clathrata_, Buetschli, 1882, Zeitschr. f. Wiss. Zool., vol. + xxxvi. pp. 506, 539; Taf. xxxii. figs. 10_a_, 10_b_. + + _Petalospyris clathrus_, Haeckel, 1862, Monogr. d. Radiol., p. 295. + +Shell campanulate or nearly spherical, smooth, with slight sagittal +stricture. Three pairs of large annular pores on each side of the +stricture; a few smaller irregular pores on the lateral sides. Basal plate +with six large collar pores (Buetschli, _loc. cit._, fig. 10_a_). Three +horns and six feet nearly of the same size and form; short, conical, +slightly divergent or nearly parallel, shorter than half the ring. (The +size of the nine appendages is in this common species rather variable; +sometimes they are rudimentary, at other times much stronger than in the +good figure of Buetschli.) + +_Dimensions._--Shell diameter 0.08 to 0.09, horns and feet 0.01 to 0.03. + +_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Pacific; also fossil in +Barbados and Sicily. + + +{1050}3. _Liriospyris heteropoda_, n. sp. + +Shell nut-shaped, nodose, with deep sagittal stricture and small circular +pores; two pairs of larger pores on each side of the stricture. Basal plate +with four larger central and eight smaller peripheral pores. Apical horn +conical, as long as the shell and twice as long as the two curved frontal +horns. Three primary feet twice as long as the shell and as the three +secondary feet, which are more highly inserted. All six feet slender +curved, divergent. + +_Dimensions._--Shell 0.07 long, 0.11 broad; horn and secondary feet 0.08 +long, primary feet 0.15 long. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +4. _Liriospyris turrita_, Haeckel. + + _Ceratospyris turrita_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 66, Taf. xx. fig. 1. + +Shell ovate, campanulate, smooth, with sharp sagittal stricture and +irregular roundish pores; three to four pairs of larger pores on each side +of the stricture. Basal plate with four large collar pores. Three horns +short and stout, conical, fenestrated at the base. Six feet slender, +conical, nearly vertical, of equal size, only one-third as long as the +shell. + +_Dimensions._--Shell 0.08 long, 0.06 broad; horns 0.01 long, feet 0.03 +long. + +_Habitat._--Fossil in Barbados. + + +5. _Liriospyris amphithecta_, n. sp. (Pl. 95, fig. 7). + +Shell nut-shaped, tuberculate, with distinct sagittal stricture and +irregular roundish pores. Basal plate with six larger and twelve smaller +pores. Three horns conical, the apical as long as the shell and twice as +long as the curved frontal horns. Two pectoral feet cylindrical, very +large, curved, divergent, about three times as long as the shell and as the +four other feet, which are conical. + +_Dimensions._--Shell 0.08 long, 0.12 broad; apical horn 0.08, frontal horns +0.05 long; length of the two pectoral feet 0.2, of the four others 0.06. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + + +Genus 455. _Cantharospyris_,[73] n. gen. + +_Definition._--#Zygospyrida# with six basal feet, without apical horn. + +The genus _Cantharospyris_ differs from the preceding two hexapodal genera +in the absence of horns on the coryphal face, and has therefore the same +relation to them that the hornless _Tristylospyris_ bears to the one-horned +_Tripospyris_ and the three-horned _Triceraspyris._ + + +{1051}1. _Cantharospyris carabus_, n. sp. + +Shell nut-shaped, with deep sagittal stricture and irregular roundish +pores. Basal plate with six larger pores. Six feet of different sizes, +cylindrical, curved; three primary feet (one caudal and two pectoral) about +as long as the shell and twice as long as the three secondary feet. + +_Dimensions._--Shell 0.08 long, 0.12 broad; feet 0.05 to 0.09 long. + +_Habitat._--Tropical Atlantic, Station 338, depth 1990 fathoms; Central +Pacific, Station 268, depth 2900 fathoms. + + +2. _Cantharospyris ateuchus_, Haeckel. + + _Ceratospyris ateuchus_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 66, Taf. xxi. fig. 4. + +Shell nut-shaped, tuberculate, with slight sagittal stricture and unequal +circular pores. Basal plate with six larger pores. The two pectoral feet +very large and stout, four to six times as long as the shell, widely +divergent, curved. The four other feet much smaller and thinner, about as +long as the shell. + +_Dimensions._--Shell 0.06 long, 0.08 broad; length of the two larger feet +0.2 to 0.3, of the four smaller 0.05 to 0.07. + +_Habitat._--Fossil in Barbados. + + +3. _Cantharospyris radicata_, Haeckel. + + _Ceratospyris radicata_, Ehrenberg, 1847, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, p. 43; Mikrogeol., 1854, Taf. xxii. fig. 37. + + _Haliomma radicatum_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 83. + + _Petalospyris radicata_, Haeckel, 1862, Monogr. d. Radiol., p. 295. + + _Petalospyris radicata_, Stoehr, 1880, Palaeontogr., vol xxvi. p. 79, + Taf. iii. fig. 11. + +Shell nut-shaped, smooth, with slight sagittal stricture and irregular +roundish pores; two larger pores on each side of the ring. Basal plate with +six pores (?). Six feet of equal size and similar form, conical, divergent, +slightly curved, shorter than half the ring. + +_Dimensions._--Shell 0.05 long, 0.08 broad; feet 0.02 long. + +_Habitat._--Fossil in Barbados and Sicily. + + +4. _Cantharospyris platybursa_, n. sp. (Pl. 53, fig. 7). + + _Platybursa compressa_, Haeckel, 1881, Prodromus, p. 429; Atlas, pl. 53, + fig. 7. + +Shell smooth, nearly discoidal circular, markedly compressed in the +sagittal direction, with slight basal stricture. Pores very numerous, +irregular polygonal, with thin bars. Basal plate with four very large +pores. Six feet short, conical, nearly horizontally expanded. Two sagittal +feet (caudal {1052}and sternal) larger, about half as long as the shell +(shortened in the figure). The two sternal feet larger than the two small +or rudimentary tergal feet. + +_Dimensions._--Shell 0.15 long, 0.13 broad; feet 0.02 to 0.06 long. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +Subfamily 5. PENTASPYRIDA, Haeckel, 1881, Prodromus, p. 442. + +_Definition._--#Zygospyrida# pentapoda, with five descending basal feet, +one odd caudal foot, and two pairs of lateral feet (two anterior or +pectoral, and two posterior or tergal feet). + + + +Genus 456. _Clathrospyris_,[74] Haeckel, 1881, Prodromus, p. 442. + +_Definition._--#Zygospyrida# with five basal feet and one apical horn. + +The genus _Clathrospyris_ and the two following closely allied genera +represent together the small subfamily of Pentaspyrida, differing from the +other Zygospyrida in the possession of five descending feet on the basal +face. Three of these are the primary cortinar feet (of _Cortiniscus_, +_Plagoniscus_, _Tripospyris_, &c.), whilst the two others are secondary +tergal feet. The Pentaspyrida may therefore be probably derived from the +Hexaspyrida by loss of the odd anterior or sternal foot. + + +1. _Clathrospyris camelopardalis_, n. sp. + +Shell nut-shaped, tuberculate, with deep sagittal stricture. Pores +irregular roundish. Basal plate with six pores (?). Two pectoral feet very +large, twice as long as the shell, cylindrical, curved. Two tergal feet +half as long and thick as the pectoral. Caudal foot and apical horn +straight, conical, half as long as the shell. + +_Dimensions._--Shell 0.07 long, 0.09 broad; horn and odd caudal foot 0.04 +long; pectoral feet 0.16, tergal 0.08 long. + +_Habitat._--South Pacific, Station 297, depth 1775 fathoms. + + +2. _Clathrospyris pyramidalis_, n. sp. (Pl. 95, fig. 9). + +Shell four-sided pyramidal, truncate, thorny, with a slight sagittal +stricture. Pores very large, polygonal roundish. Two pairs of large pores +on each side of the ring (at the frontal and the occipital plate). Lateral +pores more numerous. Basal plate with four large pores. The four edges of +the pyramid are prolonged into four short pyramidal divergent lateral feet +(one-third as {1053}long as the shell). Caudal foot short. Horn at the apex +of the truncate pyramid with two lateral teeth. + +_Dimensions._--Shell 0.06 long, 0.08 broad; horn and feet 0.02 long. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +3. _Clathrospyris fusiformis_, n. sp. + +Shell nearly cubical, smooth, with slight sagittal stricture. Pores +roundish; three pairs of larger pores on each side of the ring. Basal plate +with six large pores. Five feet of equal length, slender, spindle-shaped, +about as long as the shell, divergent. Apical horn conical, and half as +long as the feet. + +_Dimensions._--Shell 0.08 long, 0.09 broad; horn 0.05 long, feet 0.1 long. + +_Habitat._--Fossil in Barbados. + + + +Genus 457. _Aegospyris_,[75] Haeckel, 1881, Prodromus, p. 442. + +_Definition._--#Zygospyrida# with five basal feet and three coryphal horns. + +The genus _Aegospyris_ differs from the preceding _Clathrospyris_, its +ancestral form, in the possession of three horns on the coryphal face (one +odd apical, and two paired frontal horns on each side), and therefore bears +to the latter the same relation that _Triceraspyris_ does to _Tripospyris_, +and _Liriospyris_ to _Hexaspyris_. + + +1. _Aegospyris aequispina_, n. sp. + +Shell nut-shaped, tuberculate, with slight sagittal stricture. Pores +subregular circular. Basal plate with four large collar pores. Three horns +and five feet all of equal size and similar form, slender conical, slightly +curved, widely divergent, about as long as the shell. + +_Dimensions._--Shell 0.08 long, 0.11 broad; horns and feet 0.08 long. + +_Habitat._--Central Pacific, Stations 265 to 274, depth 2350 to 2925 +fathoms. + + +2. _Aegospyris octospina_, n. sp. + +Shell nearly cubical, smooth, with slight sagittal stricture. Pores +subregular circular; two pairs of larger pores on each side of the ring. +Basal plate with four large pores. Two paired horns and four paired feet of +equal size and similar form, S-shaped curved, twice as long as the shell. +Odd horn and odd feet half as long, straight, conical. + +_Dimensions._--Shell 0.08 long, 0.09 broad; six paired spines 0.2 long, two +odd spines 0.1 long. + +_Habitat._--South Atlantic, Station 323, depth 1900 fathoms. + + +{1054}3. _Aegospyris longibarba_, Haeckel. + + _Ceratospyris longibarba_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 66, Taf. xxi. figs. 1, 2. + +Shell nut-shaped, tuberculate, with slight sagittal stricture. Pores +subregular circular. Basal plate with four larger central, and eight +smaller peripheral pores. Apical horn and caudal foot short, straight, +conical; two frontal horns longer, curved; four paired feet slender, +curved, twice as long as the shell. + +_Dimensions._--Shell 0.06 long, 0.08 broad; paired horns 0.03 long, paired +feet 0.1 long. + +_Habitat._--Fossil in Barbados. + + +4. _Aegospyris aegoceras_, n. sp. (Pl. 95, fig. 10). + +Shell nut-shaped, tuberculate, with deep sagittal stricture. Pores +irregular roundish. Basal plate with three large pores. Apical horn and +caudal foot short, straight, spindle-shaped; two frontal horns as long as +the shell, strongly curved; four paired feet also curved, at the distal end +forked, divergent; the tergal thinner and as long as the shell, the +pectoral thicker and twice as long. + +_Dimensions._--Shell 0.07 long, 0.09 broad; pectoral feet 0.1 long. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +5. _Aegospyris caprina_, n. sp. (Pl. 86, fig. 8). + +Shell nut-shaped, papillate, with sharp sagittal stricture. Pores irregular +roundish, two pairs of larger pores on each side of the ring. Basal plate +with six large pores. Eight spines all straight, subvertical and nearly +parallel, cylindro-conical. Two frontal horns and two tergal feet about as +long as the shell; odd horn shorter; odd foot longer. Two pectoral feet +twice as long as the shell, club-shaped, with a spinulate knob at the +distal end. + +_Dimensions._--Shell 0.06 long, 0.09 broad; pectoral feet 0.11 long. + +_Habitat._--Central Pacific, Station 271, surface. + + + +Genus 458. _Pentaspyris_,[76] Haeckel, 1881, Prodromus, p. 442. + +_Definition._--#Zygospyrida# with five basal feet, without apical horn. + +The genus _Pentaspyris_ differs from the two preceding genera in the +absence of any coryphal horn, and represents therefore the pentapodal form +among the hornless Zygospyrida. + + +1. _Pentaspyris pentacantha_, n. sp. (Pl. 95, fig. 11). + +Shell nut-shaped, tuberculate, with deep sagittal stricture. Pores +irregular roundish, two pairs of larger pores on each side of the ring. +Basal plate with four larger pores. All five feet {1055}cylindrical, +S-shaped curved, strongly divergent, with few short branches, the two +pectoral feet twice as long as the shell and the two tergal feet; odd +caudal foot shorter. + +_Dimensions._--Shell 0.08 long, 0.13 broad; pectoral feet 0.2 long, tergal +feet 0.1, caudal foot 0.06. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +2. _Pentaspyris isacantha_, n. sp. + +Shell subspherical, smooth, with slight sagittal stricture. Pores small, +regular circular. Basal plate with six large pores (?). All five feet +equal, cylindrical, C-shaped curved, slightly divergent, about as long as +the shell. + +_Dimensions._--Shell 0.08 long, 0.09 broad; feet 0.07 long. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + + +Subfamily 6. THEROSPYRIDA, Haeckel, 1881, Prodromus, p. 442. + +_Definition._--#Zygospyrida# tetrapoda with two pairs of descending basal +feet, one pair corresponding to the anterior or pectoral, the other pair to +the posterior or tergal feet of the Hexaspyrida. + + + +Genus 459. _Zygospyris_,[77] Haeckel, 1881, Prodromus, p. 442. + +_Definition._--#Zygospyrida# with two pairs of lateral feet and an apical +horn. + +The genus _Zygospyris_ and the following three genera represent together +the peculiar subfamily of Therospyrida. These always possess four basal +feet, like the Tetraspyrida; but whilst in the latter group two feet are +sagittal, and two lateral, in the Therospyrida there are no sagittal feet +at all, but the four feet are opposed in two lateral pairs; the anterior +pair corresponds to the pectoral, the posterior to the tergal feet of the +Hexaspyrida and Pentaspyrida; from these latter the Therospyrida have been +derived by loss of the sagittal feet. + + +1. _Zygospyris quadrupes_, n. sp. + +Shell nut-shaped, tuberculate, with deep sagittal stricture. Pores +irregular roundish, on each side of the ring two pairs of larger pores. +Apical horn conical, straight. Four feet equal, straight, divergent, +conical, about as long as the shell and the horn. + +_Dimensions._--Shell 0.08 long, 0.11 broad; horn and feet 0.1 long. + +_Habitat._--South Atlantic, Station 335, depth 1425 fathoms. + + +{1056}2. _Zygospyris equus_, n. sp. (Pl. 83, fig. 16). + +Shell subspherical, rough, with slight sagittal stricture. Pores small and +numerous, subregular circular; no larger annular pores. Apical horn +cylindrical, half as long as the shell. Two pectoral feet somewhat smaller +than the two tergal feet, about as long as the shell, slightly divergent, +cylindrical. The distal ends of the feet and of the horn form an ovate, +dimpled and spinulate cone. + +_Dimensions._--Shell 0.06 long, 0.09 broad; horn 0.04 long, feet 0.06 long. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + + +Genus 460. _Elaphospyris_,[78] Haeckel, 1881, Prodromus, p. 442. + +_Definition._--#Zygospyrida# with two pairs of lateral feet and three +coryphal horns. + +The genus _Elaphospyris_ differs from the preceding _Zygospyris_, its +ancestral form, in the possession of three coryphal horns (one odd apical +and two paired frontal horns), and therefore bears to it the same relation +that _Triceraspyris_ does to _Tripospyris_ among the Tripospyrida. + + + +Subgenus 1. _Giraffospyris_, Haeckel, 1881, Prodromus, p. 442. + +_Definition._--Feet simple, not branched nor forked. + + +1. _Elaphospyris heptaceros_, Haeckel. + + _Ceratospyris heptaceros_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 66, Taf. xx. fig. 2. + + _Giraffospyris heptaceros_, Haeckel, 1881, Prodromus, p. 442. + +Shell nut-shaped, tuberculate, with slight sagittal stricture and +subregular circular pores. Basal plate with four large pores. Apical horn +small, conical, shorter than the two curved lateral horns, which are as +long as the shell. Caudal and sternal feet small, conical, straight. Two +pectoral feet slender, divergent, S-shaped, about as long as the shell. + +_Dimensions._--Shell 0.05 long, 0.07 broad; horns and feet 0.02 to 0.08 +long. + +_Habitat._--Fossil in Barbados. + + +2. _Elaphospyris capricornis_, n. sp. + +Shell nut-shaped, spiny, with slight sagittal stricture and numerous small +circular pores. Basal plate with four large pores. Three horns slender, +simple, about as long as the shell, the middle one straight, the two +lateral curved. Four feet of nearly equal size, slender, curved, divergent, +simple, twice as long as the shell and the horns. + +_Dimensions._--Shell 0.07 long, 0.09 broad; horns 0.08 long, feet 0.15 +long. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + + +{1057}Subgenus 2. _Corythospyris_, Haeckel, 1881, Prodromus, p. 443. + +_Definition._--Feet branched or forked. + + +3. _Elaphospyris damaecornis_, n. sp. (Pl. 84, fig. 10). + +Shell flat and broad, nearly triangular, with slight sagittal stricture and +irregular roundish pores; two very large pores on the frontal and on the +occipital face, opposite on both edges of the broad sagittal ring. Basal +plate with four large central and several smaller lateral pores. Three +horns about half as long as the shell, with two to six irregular branches. +Four feet of equal size, about as long as the shell, divergent, forked, +with four to six irregular terminal branches. (The shell in fig. 10 is seen +from the apical side.) + +_Dimensions._--Shell 0.09 long, 0.13 broad; horns 0.05 long, feet 0.1 long. + +_Habitat._--Indian Ocean, Cocos Islands, Rabbe, surface. + + +4. _Elaphospyris cervicornis_, n. sp. (Pl. 86, fig. 13). + +Shell polyhedral, spiny, with deep sagittal stricture and a small number of +large roundish pores; two pairs of large pores on each side of the ring. +Basal plate with four pores. Three large horns as long as the shell arise +from the apex between smaller conical spines; the middle odd horn simple, +the two lateral each with a pair of branches. Two pectoral feet very large, +divergent, with broad and irregular distal ramification, twice as long as +the shell and as the two tergal feet, which are less branched. (Fig. 13 +exhibits the shell from the dorsal side.) + +_Dimensions._--Shell 0.09 long, 0.11 broad; horns and smaller feet 0.07 to +0.09 long; pectoral feet 0.16 long. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +5. _Elaphospyris alcicornis_, n. sp. (Pl. 86, fig. 12). + +Shell nut-shaped, spiny, with sharp sagittal stricture and large roundish +pentagonally framed pores; three pairs of larger pores on each side of the +ring. Basal plate with four larger and four alternate smaller pores. There +arise from the apex, between smaller spines, three large, divergent, +pyramidal horns, which are nearly as long as the shell, and connected by an +arched frontal bridge. Two pectoral feet very large, divergent, prismatic, +longer than the shell, and at the distal end with a bunch of thick spines. +Two tergal feet half as long and thick, simple (in the figure hidden behind +the large pectoral feet). + +_Dimensions._--Shell 0.09 long, 0.11 broad; horns and smaller feet 0.06 +long, pectoral feet 0.12 long. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + + +{1058}Genus 461. _Taurospyris_,[79] Haeckel, 1881, Prodromus, p. 442. + +_Definition._--#Zygospyrida# with two pairs of lateral feet and one pair of +lateral horns. + +The genus _Taurospyris_ bears only two frontal horns in the coryphal face +of the shell, and may therefore be derived from the preceding closely +allied _Elaphospyris_ by reduction and loss of the middle or apical horn. + + +1. _Taurospyris cervina_, n. sp. (Pl. 95, fig. 12). + +Shell nut-shaped, thorny, with deep sagittal stricture and irregular +roundish pores; three pairs of larger pores on each side of the ring. Basal +plate with four large pores. Two horns cylindrical, curved, widely +divergent, about as long as the shell, branched. Four feet of nearly equal +length, also cylindrical and curved, divergent, somewhat longer than the +shell, in the distal half branched like a deer's antler. + +_Dimensions._--Shell 0.07 long, 0.11 broad; horns 0.03 long, feet 0.06 +long. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms; also fossil in +Barbados. + + +2. _Taurospyris bovina_, n. sp. + +Shell subspherical, smooth, with slight sagittal stricture and small +circular pores. Basal plate with six larger pores. Two horns conical, +curved, divergent, about as long as the shell. Two pectoral feet very +large, twice as long as the shell and as the two thinner tergal feet; all +four feet curved, cylindrical, divergent, pointed at the distal end. + +_Dimensions._--Shell 0.08 long, 0.09 broad; horns and posterior feet 0.1, +anterior feet 0.2 long. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + + +Genus 462. _Therospyris_,[80] Haeckel, 1881, Prodromus, p. 442. + +_Definition._--#Zygospyrida# with two pairs of lateral feet, without apical +horn. + +The genus _Therospyris_ has two pairs of lateral feet corresponding to +those of the preceding three genera, but differs from them in the complete +absence of horns on the coryphal face of the shell. + + +1. _Therospyris canis_, n. sp. + +Shell nut-shaped, tuberculate, with deep sagittal stricture. Pores +irregular, roundish. Basal plate with four longer pores. Surface covered +with roundish tubercles. Four feet equal, divergent, about as long as the +shell, thickened at the distal end, club-shaped, not forked. + +_Dimensions._--Shell 0.07 long, 0.11 broad; feet 0.09 long. + +_Habitat._--Fossil in Barbados. + + +{1059}2. _Therospyris felis_, n. sp. (Pl. 89, fig. 6). + +Shell nut-shaped, mammillate, with sharp sagittal stricture. Pores large, +irregularly roundish or polygonal, of somewhat different size. Basal plate +with four large pores. Surface covered with hemispherical pointed +mammillae. Four feet equal, divergent, half as long as the shell, at the +distal end forked, with few small branches. + +_Dimensions._--Shell 0.1 long, 0.15 broad; feet 0.05 long. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +3. _Therospyris leo_, n. sp. (Pl. 89, fig. 5). + +Shell nearly cubical, papillate, with slight sagittal stricture. Pores +irregular, roundish; on each side of the ring three pairs of larger pores +(the undermost the largest). Basal plate with two large pores. Surface +covered with conical papillae. Four feet equal, divergent, about as long as +the shell, with an external spur in the middle, and irregularly branched +spines at the distal end. + +_Dimensions._--Shell 0.08 long, 0.12 broad; feet 0.09 long. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + + +Subfamily 7. POLYSPYRIDA, Haeckel, 1881, Prodromus, p. 442. + +_Definition._--#Zygospyrida# polypoda, with numerous descending basal feet +(at least seven to nine, usually twelve to sixteen or more). + + + +Genus 463. _Petalospyris_,[81] Ehrenberg, 1847, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 54. + +_Definition._--#Zygospyrida# with numerous (seven to twelve or more) basal +feet and one apical horn. + +The genus _Petalospyris_ and the following three genera form together the +peculiar subfamily of Polyspyrida, differing from the other Zygospyrida in +the multiplication of the radial feet, which descend from the basal face of +the shell; they may therefore be also called "Zygospyrida multiradiata," +and bear the closest relationship to the Archiphaenida (or the "Monocyrtida +multiradiata"). They differ, however, from the latter in the presence of +the distinct sagittal stricture, characteristic of all #Spyroidea#. The +number of the basal feet, which form a coronet around the margin of the +basal plate, is commonly between twelve and sixteen, but often more. Their +form is usually flat, lamellar, but often also more or less cylindrical or +conical. + + + +{1060}Subgenus 1. _Petalospyrantha_, Haeckel. + +_Definition._--Basal plate with two large collar pores only, separated by +the base of the primary ring. + + +1. _Petalospyris foveolata_, Ehrenberg. + + _Petalospyris foveolata_, Ehrenberg, 1854, Mikrogeol., Taf. xxxvi. fig. + 14; Abhandl. d. k. Akad. d. Wiss. Berlin, 1875, p. 80, Taf. xxii. fig. + 10. + +Shell campanulate, smooth, with distinct sagittal stricture and subregular +circular pores. Basal plate with two large collar pores only. Apical horn +and the eight feet slender, conical, slightly curved, about as long as the +shell; feet somewhat divergent (often seven or nine instead of eight). + +_Dimensions._--Shell diameter 0.04 to 0.05; length of the horn and the feet +0.04 to 0.05. + +_Habitat._--Fossil in Barbados. + + +2. _Petalospyris floscula_, n. sp. + +Shell nut-shaped, tuberculate, with deep sagittal stricture and subregular +circular pores. Basal plate with two large triangular pores only. Apical +horn slender, conical, twice as long as the shell. Twelve to sixteen feet +flattened, leaf-shaped, broad, slightly divergent, as long as the shell, +with truncate distal end. + +_Dimensions._--Shell 0.06 long, 0.09 broad; horn 0.12 long, feet 0.05 to +0.07 long. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + + +Subgenus 2. _Petalospyrella_, Haeckel. + +_Definition._--Basal plate with three large collar pores (two paired +posterior cardinal, and an odd anterior sternal pore). + + +3. _Petalospyris triomma_, n. sp. (Pl. 87, fig. 14). + +Shell nut-shaped, tuberculate, with sharp sagittal stricture and irregular +roundish pores. Basal plate with three large pores and three alternate +smaller. Apical horn stout, conical, half as long as the shell. Twelve to +fifteen feet, divergent, curved, pointed, as long as the horn. + +_Dimensions._--Shell 0.06 long, 0.08 broad; horn and feet 0.03 long. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +4. _Petalospyris platyacantha_, Ehrenberg. + + _Petalospyris platyacantha_, Ehrenberg, Abhandl. d. k. Akad. d. Wiss. + Berlin, 1875, p. 80, Taf. xxii. fig. 8. + +Shell campanulate, smooth, with slight sagittal stricture and small +irregular roundish pores. Basal plate with three large pores (?). Apical +horn very strong, three-sided pyramidal, twice as {1061}long as the shell +(its edge is described by Ehrenberg as a "canaliculus.") Feet ten to +twelve, flat, triangular, vertical, about as long as the shell. + +_Dimensions._--Shell 0.04 long, 0.05 broad; 0.07 long, feet 0.03 long. + +_Habitat._--Fossil in Barbados. + + +5. _Petalospyris corona_, Stoehr. + + _Petalospyris corona_, Stoehr, 1880, Palaeontogr., vol. xxvi. p. 98, Taf. + iii. fig. 13. + +Shell nut-shaped, smooth, with slight sagittal stricture and very numerous +small circular pores; on each side of the stricture three larger annular +pores (the undermost the largest). Basal plate with three large pores only. +Apical horn very small, conical. Feet twelve to eighteen, short conical, +nearly vertical, shorter than the half shell (in my specimen from +Caltanisetta much stouter than in that of Stoehr). + +_Dimensions._--Shell 0.07 long, 0.09 broad; horn and feet 0.01 to 0.03 +long. + +_Habitat._--Fossil in Tertiary rocks of Sicily (Grotte, Caltanisetta). + + + +Subgenus 3. _Petalospyrissa_, Haeckel. + +_Definition._--Basal plate with four collar pores (two larger posterior +cardinal and two smaller anterior jugular pores). + + +6. _Petalospyris octopus_, n. sp. (Pl. 87, fig. 11). + +Shell nut-shaped, tuberculate, with sharp sagittal stricture and irregular, +roundish pores. Basal plate with four larger pores. Horn slender, conical, +half as long as the shell. Feet eight, very slender, about three times as +long as the shell, subvertical, with outer convex edge and convergent ends. + +_Dimensions._--Shell 0.06 long, 0.09 broad; horn 0.03 long, feet 0.2 long. + +_Habitat._--Tropical Atlantic, Station 342, depth 1445 fathoms. + + +7. _Petalospyris eupetala_, Ehrenberg. + + _Petalospyris eupetala_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 80, Taf. xxii. fig. 4. + +Shell nut-shaped, tuberculate, with slight sagittal stricture and scattered +small circular pores. Basal plate with four large collar pores (sometimes +surrounded by several small peripheral pores). Apical horn slender, +conical, as long as the shell. Feet sixteen to twenty, laminated and +truncate, of the same length, nearly vertical and parallel. + +_Dimensions._--Shell 0.06 long, 0.08 broad; horn and feet 0.05 to 0.07 +long. + +_Habitat._--Fossil in Barbados. + + +{1062}8. _Petalospyris anthemis_, n. sp. + +Shell nut-shaped, spinulate, with deep sagittal stricture and irregular, +roundish pores. Basal plate with four large pores of equal size. Apical +horn conical, twice as long as the shell. Feet twenty to thirty, laminated +and truncate, as long as the shell, divergent. + +_Dimensions._--Shell 0.05 long, 0.08 broad; horn 0.1 long, feet 0.6 long. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +9. _Petalospyris tessaromma_, n. sp. + +Shell subspherical, with slight sagittal stricture and few small pores; on +each side of the stricture four larger, square, annular pores. Basal plate +with four large collar pores (two larger cardinal and two smaller jugular +pores). Horn and feet conical, about half as long as the shell. Feet twenty +to twenty-five, slightly curved, convergent. + +_Dimensions._--Shell diameter 0.08; horn and feet 0.04. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms; also fossil +in Barbados. + + + +Subgenus 4. _Petalospyromma_, Haeckel. + +_Definition._--Basal plate with numerous (six or more) collar pores, +commonly three or four larger central, and six to twelve smaller peripheral +pores. + + +10. _Petalospyris novena_, n. sp. (Pl. 83, fig. 12). + +Shell nut-shaped, tuberculate, with slight sagittal stricture and +irregular, roundish pores. Basal plate with nine pores (three large primary +and three alternate pairs of small secondary pores). Nine long +corresponding feet, twice to four times as long as the shell (three very +thick primary, and three alternate pairs of thin secondary feet). All feet +cylindrical, curved, widely divergent. Horn conical. + +_Dimensions._--Shell 0.06 long, 0.08 broad; horn and feet 0.15 to 0.25. + +_Habitat._--Indian Ocean (Cocos Islands), Rabbe, surface. + + +11. _Petalospyris argiscus_, Ehrenberg. + + _Petalospyris argiscus_, Ehrenberg, 1875, Abhandl. d. k. Akad. Wiss. + Berlin, p. 80, Taf. xxii. figs. 1, 2. + + _Petalospyris argiscus_, Buetschli, 1882, Zeitschr. f. wiss. Zool., vol. + xxxvi. p. 539, Taf. xxxii. fig. 17, _a_, _b_. + +Shell nut-shaped, tuberculate, with slight sagittal stricture and +irregular, roundish pores. Basal plate with nine pores (three larger +central and three alternate pairs of smaller peripheral pores). +{1063}Apical horn slender, spindle-shaped, about as long as the shell. +Twenty to twenty-five feet, of the same length, broad, lamellar and +truncate, nearly vertical, slightly divergent. + +_Dimensions._--Shell 0.06 long, 0.1 broad; horn and feet 0.05 to 0.07 long. + +_Habitat._--Fossil in Barbados. + + +12. _Petalospyris papillata_, n. sp. + +Shell nearly cubical, papillate, without external sagittal stricture, with +small, irregular, roundish pores. Basal plate with six pores (three larger +and three alternate smaller). Apical horn conical, half as long as the +shell. Feet twenty to thirty, one-half to one-third as long, conical, +divergent. + +_Dimensions._--Shell diameter 0.09; horn 0.04 long, feet 0.03 to 0.05 long. + +_Habitat._--North Atlantic, Station 353, depth 2965 fathoms. + + +13. _Petalospyris dictyocubus_, n. sp. (Pl. 86, fig. 6). + +Shell nearly cubical, smooth, without external stricture, but with a +complete, parietal, square, sagittal ring. On each side of the ring four +pairs of larger pores, whilst the lateral pores are smaller and more +numerous. Basal plate also with four pairs of larger pores and smaller +lateral pores. Apical horn and basal feet short, pyramidal, scarcely +one-fourth as long as the shell. The three primary feet are larger than the +six to nine secondary feet. + +_Dimensions._--Shell diameter 0.08; horn and feet 0.02 long. + +_Habitat._--Central Pacific, Station 274, surface. + + +14. _Petalospyris bellidiastrum_, n. sp. + +Shell nut-shaped, tuberculate, with slight sagittal stricture and +irregular, roundish pores. Basal plate with twelve pores (four central +larger and eight peripheral smaller pores). Apical horn slender, conical, +about as long as the shell (sometimes ramified at the distal end). Feet +sixteen to twenty, broadly lamellar, truncate, divergent, about as long as +the shell. + +_Dimensions._--Shell 0.08 long, 0.1 broad; horn and feet 0.07 to 0.09 long. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms; also fossil +in Barbados. + + +15. _Petalospyris dinoceras_, n. sp. (Pl. 87, fig. 12). + +Shell nut-shaped, mammillate, without external stricture, but with complete +external sagittal ring. Pores subregular, circular. Basal plate with four +large central pores, surrounded by a circle of twelve to twenty small +peripheral pores. Apical horn very large, spindle-shaped, one and a half +times as long as the shell. Feet twenty-five to thirty, broadly lamellar, +truncate, divergent, about as long as the shell. + +_Dimensions._--Shell 0.11 long, 0.13 broad; horn 0.15 long, feet 0.09 long. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +{1064}16. _Petalospyris furcata_, n. sp. + +Shell nut-shaped, smooth, with sharp sagittal stricture. Pores numerous, +small, and circular; no larger annular pores. Basal plate with four larger +and four alternate pairs of smaller pores. Horn conical, about as long as +the shell. Feet fifteen to twenty, broadly lamellar, about twice as long as +the shell, in the distal half forked. + +_Dimensions._--Shell 0.04 long, 0.06 broad; horn 0.05 long, feet 0.1 long. + +_Habitat._--South Pacific, Station 300, depth 1375 fathoms. + + +17. _Petalospyris lobata_, n. sp. (Pl. 87, fig. 13). + +Shell subspherical, smooth, with slight sagittal stricture. Pores small, +roundish; on each side of the ring two pairs of larger annular pores. Basal +plate with four pores. Horn stout, three-sided prismatic, half as long as +the shell. Feet twelve to sixteen, lamellar, lobate (the most part with +three lobes), nearly vertical, about as long as the shell. + +_Dimensions._--Shell diameter 0.05; horn 0.03, feet 0.05 long. + +_Habitat._--South Atlantic, Station 335, depth 1425 fathoms. + + + +Genus 464. _Anthospyris_,[82] Haeckel, 1881, Prodromus, p. 443. + +_Definition._--#Zygospyrida# with numerous (seven to nine or more) basal +feet and three coryphal horns. + +The genus _Anthospyris_ differs from the preceding _Petalospyris_, its +ancestral form, in the possession of three horns on the coryphal face (one +odd middle apical horn and two paired frontal horns, one on each side). The +former therefore bears to the latter the same relation that _Triceraspyris_ +does to _Tripospyris_ and _Liriospyris_ to _Hexaspyris._ + + +1. _Anthospyris mammillata_, n. sp. (Pl. 87, fig. 16). + +Shell nut-shaped, mammillate, with deep sagittal stricture and irregular, +polygonal pores. Basal plate with two large ovate pores (?). The pediculate +apical horn and the two frontal horns stout and short, conical, twice to +three times as large as the conical papillae of the surface. Feet twelve to +fifteen, lanceolate lamellar, pointed, divergent, about as long as the +shell. + +_Dimensions._--Shell 0.05 long, 0.08 broad; horns 0.03, feet 0.04 long. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +{1065}2. _Anthospyris spathulata_, n. sp. (Pl. 87, fig. 15). + +Shell subspherical, thorny, with slight sagittal stricture and irregular, +roundish pores. Basal plate with three large pores. The three horns +spindle-shaped, half as long as the ten to twelve thin feet, which are +pediculate, shovel-shaped, a little divergent, and shorter than the shell. + +_Dimensions._--Shell 0.05 diameter; horn 0.02 long, feet 0.04 long. + +_Habitat._--North Pacific, Station 250, depth 3050 fathoms. + + +3. _Anthospyris diaboliscus_, Haeckel. + + _Petalospyris diaboliscus_, Ehrenberg, 1854, Mikrogeol., Taf. xxxvi. fig. + 12; Abhandl. d. k. Akad. d. Wiss. Berlin, 1875, p. 80, Taf. xxii. fig. 3. + +Shell nut-shaped, smooth, with slight sagittal stricture and small circular +pores. Basal plate with four large pores. Apical horn straight conical, +frontal horns curved laterally. Feet nine to twelve, of about the same +length as the horns and the shell, broad lamelliform, truncate, nearly +vertical, slightly curved. + +_Dimensions._--Shell 0.04 long, 0.07 broad; horns and feet 0.05 to 0.07 +long. + +_Habitat._--Fossil in Barbados. + + +4. _Anthospyris arachnoides_, Haeckel. + + _Petalospyris arachnoides_, Haeckel, 1862, Monogr. d. Radiol., p. 294, + Taf. xii. fig. 7. + +Shell nut-shaped, tuberculate, with slight sagittal stricture and +irregular, polygonal pores. Basal plate with four large pores (?). Apical +horn straight, conical, longer than the two curved lateral horns. Feet ten, +slender, S-shaped, widely divergent, about as long as the shell is broad. + +_Dimensions._--Shell 0.05 long, 0.08 broad; horns 0.03 to 0.05 long, feet +0.08 long. + +_Habitat._--Mediterranean (Messina), Atlantic, Station 354, surface. + + +5. _Anthospyris aculeata_, n. sp. (Pl. 86, fig. 5). + +Shell campanulate, spiny, with deep sagittal stricture and irregular, +roundish pores. On each side of the stricture three pairs of larger annular +pores. Basal plate with two large square pores. The three horns of the same +size as, and similar form to, the ten to fifteen feet, slender pyramidal, +straight, divergent, about half as long as the shell. (This species is very +variable and closely allied to _Ceratospyris_.) + +_Dimensions._--Shell diameter 0.08 to 0.12; horns and feet 0.04 to 0.06 +long. + +_Habitat._--Central Pacific, Stations 266 to 274, surface. + + +6. _Anthospyris doronicum_, n. sp. (Pl. 87, fig. 18). + +Shell nut-shaped, spiny, with a deep sagittal stricture and small circular +pores. On each side of the stricture two pairs of very large square annular +pores. Basal plate with four larger collar {1066}pores and a corona of +numerous small peripheral pores. Three horns spindle-shaped, divergent, +about half as long as the shell. Feet twenty-five to thirty, broad, +lamellar, lanceolate, pointed, divergent, nearly as long as the shell. + +_Dimensions._--Shell 0.1 long, 0.13 broad; horns 0.06, feet 0.09 long. + +_Habitat._--South Pacific, Station 296, depth 1825 fathoms. + + +7. _Anthospyris tragopogon_, n. sp. (Pl. 87, fig. 17). + +Shell nut-shaped, tuberculate, with distinct sagittal stricture and small +regular circular pores. Basal plate with numerous small pores. Apical horn +very large, spindle-shaped, twice as long as the shell; frontal horns +small, scarcely one-fourth as long, curved laterally. Feet twenty-five to +thirty, three to four times as long as the shell, lamellar, lanceolate, +pointed, parallel, vertical. + +_Dimensions._--Shell 0.08 long, 0.11 broad; apical horn 0.16, feet 0.2 +long. + +_Habitat._--Central Pacific, Stations 265 to 268, depth 2700 to 2900 +fathoms. + + + +Genus 465. _Ceratospyris_,[83] Ehrenberg, 1847, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 54. + +_Definition._--#Zygospyrida# with numerous (seven to twelve or more) basal +feet and numerous coryphal horns. + +The genus _Ceratospyris_ differs from all the other Zygospyrida in the +possession of numerous large spines on the surface of the shell, which +usually exhibits only a small number of large pores or meshes. The lower +spines which cover the inferior or basal face of the shell (usually nine to +twelve or more) may be compared to the descending "basal feet" of the other +Zygospyrida; the upper spines, however, which cover the superior or +coryphal face (usually six to nine, rarely more), may be regarded as +"coryphal horns." In many species of this genus the lattice-work of the +shell is of a peculiar loose kind, with few large meshes, resembling the +wicker-work of the Plectanida. + + + +Subgenus 1. _Lophospyris_, Haeckel, 1881, Prodromus, p. 443. + +_Definition._--Spines simple, not branched. Meshes of the shell usually +polygonal, or roundish with polygonal frames. Bars of the network +prismatic. + + +1. _Ceratospyris polygona_, n. sp. (Pl. 86, fig. 1). + +Shell polyhedral, with deep sagittal stricture, studded with twenty-four to +thirty long simple straight slender pyramidal spines, which are as long as +the shell or longer. All pores large, polygonal. On the frontal and the +occipital face two pairs of very large pores only, the superior +{1067}pentagonal, larger than the inferior tetragonal. Basal plate with two +triangular pores. Bars of the loose framework three-sided prismatic, thin. + +_Dimensions._--Shell 0.08 long, 0.12 broad; spines 0.06 to 0.12 long. + +_Habitat._--Cosmopolitan; Atlantic, Indian, Pacific, surface. + + +2. _Ceratospyris pentagona_, Ehrenberg. + + _Ceratospyris pentagona_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 287, Taf. x. fig. 15. + +Shell polyhedral, with slight sagittal stricture, studded with twenty-four +to thirty small simple conical spines, which are shorter than one-fourth of +the shell. Most pores pentagonal. On the frontal and the occipital face two +pairs of large pores only, the superior smaller than the inferior. Basal +plate with four quadrangular pores. Bars of the network prismatic, thin. + +_Dimensions._--Shell 0.07 long, 0.11 broad; spines 0.01 to 0.02 long. + +_Habitat._--Cosmopolitan; Atlantic, Indian, Pacific, surface. + + +3. _Ceratospyris allmersii_, n. sp. (Pl. 86, fig. 3). + +Shell polyhedral, with slight sagittal stricture, studded with thirty to +forty prismatic spines which are not longer than half the shell. Most pores +pentagonal. On the frontal face two, on the occipital three pairs of larger +pores; the inferior the largest. Basal plate with two rhomboidal pores (?). +Bars of the network three-sided prismatic, thin. Dedicated to my dear +friend, the excellent poet and naturalist, Hermann Allmers, of +Rechtenfleth. + +_Dimensions._--Shell 0.08 long, 0.12 broad; spines 0.01 to 0.03. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + +4. _Ceratospyris mulderi_, n. sp. (Pl. 86, fig. 4). + +Shell polyhedral, with deep sagittal stricture, studded with fifty to +seventy prismatic spines; two inferior (pectoral) spines about as long as +the shell, the others much shorter. Pores polygonal. On the frontal and the +occipital face one pair of very large pores. Basal plate with two +distinctly hexagonal pores. Bars of the loose network prismatic. Dedicated +to my dear friend, the excellent author and painter, Ludwig Mulder, of the +Hague. + +_Dimensions._--Shell 0.07 long, 0.12 broad; spines 0.01 to 0.08. + +_Habitat._--Indian Ocean, Sunda Straits (Rabbe), surface. + + +5. _Ceratospyris strasburgeri_, n. sp. (Pl. 86, fig. 2). + +Shell polyhedral, with slight sagittal stricture, studded with thirty to +forty prismatic spines, which are about half as long as the shell (two or +four inferior are longer). Pores roundish, with polygonal frames. On the +frontal and occipital face two pairs of larger pores (the superior +{1068}smaller). Basal plate with two large pentagonal pores. Bars of the +network prismatic. Dedicated to my dear friend, the celebrated botanist, +Professor Eduard Strasburger, of Bonn. + +_Dimensions._--Shell 0.07 long, 0.1 broad; spines 0.02 to 0.04. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475. + + +6. _Ceratospyris muelleri_, Stoehr. + + _Ceratospyris muelleri_, Stoehr, 1880, Palaeontogr., vol. xxvi. Taf. iii. + fig. 15. + +Shell polyhedral, with slight collar stricture, studded with forty to fifty +pyramidal spines, shorter than half the shell. Pores circular, with +pentagonal frames of the same breadth, all nearly of equal size. (Basal +plate with four pores?) Bars of the network prismatic. Dedicated to +Johannes Mueller. + +_Dimensions._--Shell 0.08 long, 0.1 broad; spines 0.01 to 0.03. + +_Habitat._--Fossil in Tertiary rocks of Sicily, Grotte (Stoehr). + + +7. _Ceratospyris krausei_, n. sp. (Pl. 86, fig. 10). + +Shell nut-shaped, with deep sagittal stricture, studded with forty to fifty +strong conical spines; six basal spines as long as the shell and two to +three times as long as the others. Pores roundish polygonal, twice to three +times as broad as the bars; two pairs of larger pores on each side of the +ring. (Basal plate with four large pores?) Bars of the network rounded, +thick. Dedicated to my dear friend, the excellent author, Ernst Krause +(Carus Sterne), of Berlin. + +_Dimensions._--Shell 0.06 long, 0.09 broad; spines 0.03 to 0.08. + +_Habitat._--Western Tropical Pacific (Philippine Sea), Station 206, depth +2100 fathoms. + + +8. _Ceratospyris preyeri_, n. sp. (Pl. 86, fig. 9). + +Shell nut-shaped, with slight sagittal stricture, studded with ten to +twelve longer club-shaped spines (about as long as the shell) and numerous +smaller conical spines. Pores irregular, roundish, numerous; two pairs of +larger pores on each side of the ring. Basal plate with four large pores. +Bars of the network rounded. Dedicated to my honoured friend and colleague, +the celebrated investigator of psychical ontogeny, Professor William +Preyer, of Jena. + +_Dimensions._--Shell 0.07 long, 0.09 broad; spines 0.02 to 0.08 long. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +9. _Ceratospyris echinus_, Ehrenberg. + + _Ceratospyris echinus_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 66, Taf. xx, fig. 12. + +Shell subspherical, with slight sagittal stricture, studded with numerous +conical curved spines; six basal and one apical spine are larger than the +others, about as long as the shell. Pores numerous, small, circular. Basal +plate with numerous pores. Bars of the network roundish. + +_Dimensions._--Shell 0.05 long, 0.06 broad; spines 0.02 to 0.05 long. + +_Habitat._--Fossil in Barbados. + + + +{1069}Subgenus 2. _Cladospyris_, Ehrenberg, 1847, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 54. + +_Definition._--Spines forked or branched. Meshes roundish or polygonal. + + +10. _Ceratospyris ramosa_, Ehrenberg. + + _Ceratospyris ramosa_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 66, Taf. xx. fig. 7. + + _Cladospyris ramosa_, Ehrenberg, 1847, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 54. + +Shell nut-shaped, with slight sagittal stricture, studded with numerous +conical, irregularly branched spines. The largest about as long as the +shell. Pores irregular, roundish; on each side of the ring two pairs of +larger pores. Basal plate with four pores. Bars of the network roundish. + +_Dimensions._--Shell 0.06 long, 0.08 broad; spines 0.02 to 0.08 long. + +_Habitat._--Fossil in Barbados. + + +11. _Ceratospyris carnerii_, n. sp. (Pl. 86, fig. 11). + +Shell nut-shaped, with sharp sagittal stricture, studded with numerous +pyramidal spines; two basal spines are larger, as long as the shell, and +irregularly branched. Pores polygonal; on each side of the ring three pairs +of larger pores. Basal plate with four large pores. Dedicated to my dear +friend, the excellent monistic philosopher, B. von Carneri. + +_Dimensions._--Shell 0.09 long, 0.12 broad; spines 0.02 to 0.08 long. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +12. _Ceratospyris calorrhiza_, n. sp. (Pl. 87, fig. 19). + +Shell nut-shaped, with deep sagittal stricture, studded with numerous +conical strong spines, about one-fourth as long as the shell. Basal spines +irregularly branched, with root-like ends. Pores irregular, roundish, some +larger pores on each side of the ring. Basal plate with four larger pores. +Bars of the network roundish. + +_Dimensions._--Shell 0.1 long, 0.14 broad; spines 0.02 to 0.04 long. + +_Habitat._--Central Pacific, Station 271, surface. + + + +Genus 466. _Gorgospyris_,[84] Haeckel, 1881, Prodromus, p. 443. + +_Definition._--#Zygospyrida# with numerous (seven to twelve or more) basal +feet, without coryphal horns. + +The genus _Gorgospyris_ agrees with the three preceding genera in the +possession of numerous basal feet, but differs from them in the complete +absence of any horns on the coryphal face. It represents therefore the +"hornless polypedal Zygospyrida," and may {1070}be derived from +_Petalospyris_ by loss of the original apical horn. The feet are commonly +numerous, and often form a circle around the margin of the basal plate, +similar to the circle of tentacles in many Medusae (Gorgon). + + + +Subgenus 1. _Gorgospyrium_, Haeckel. + +_Definition._--Feet simple, not branched. + + +1. _Gorgospyris medusa_, n. sp. (Pl. 87, fig. 1). + +Shell hemispherical, papillate, with slight sagittal stricture and +subregular circular pores. Basal plate with three large collar pores (by +mistake not correctly represented in the figure). Ten to twelve slender +feet, twice as long as the shell, strongly curved and divergent, of equal +length. + +_Dimensions._--Shell 0.06 long, 0.08 broad; feet 0.1 long. + +_Habitat._--North Pacific, Station 241, depth 2300 fathoms. + + +2. _Gorgospyris medusetta_, n. sp. (Pl. 87, fig. 2). + +Shell misshaped, smooth, with deep sagittal stricture and irregular, +roundish pores. Basal plate with three large collar pores, alternating with +three pairs of smaller pores. Sixteen to twenty slender feet, about as long +as the shell, slightly curved and divergent, of nearly equal length. + +_Dimensions._--Shell 0.05 long, 0.08 broad; feet 0.05 long. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + +3. _Gorgospyris ehrenbergii_, Haeckel. + + _Petalospyris pentas_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 80, Taf. xxii. fig. 11. + +Shell nut-shaped, smooth, with slight sagittal stricture and unequal +circular pores. Basal plate with three large central pores, alternating +with three pairs of smaller pores, and with a peripheral circle of smaller +pores. Twenty-four to thirty short truncated feet, shorter than half the +shell. + +_Dimensions._--Shell 0.05 long, 0.07 broad; feet 0.02 long. + +_Habitat._--Fossil in Barbados. + + +4. _Gorgospyris polypus_, n. sp. (Pl. 87, fig. 3). + +Shell hemispherical, papillate, with slight sagittal stricture and +subregular circular pores. Basal plate with four larger and four +alternating smaller pores. Feet sixteen to twenty, slender, carved, +divergent; four primary feet larger, twice to three times as long as the +shell and the other feet. + +_Dimensions._--Shell 0.08 long, 0.1 broad; feet 0.1 to 0.2 long. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +{1071}5. _Gorgospyris eurycolpos_, n. sp. (Pl. 87, fig. 5). + +Shell nut-shaped, rough, with deep sagittal stricture and irregular, +roundish pores; two to three pairs of larger annular pores on each side of +the stricture. Basal plate with four large collar pores. Feet eight, short, +triangular, vertical, about one-fourth as long as the shell. + +_Dimensions._--Shell 0.08 long, 0.13 broad; feet 0.02 long. + +_Habits._--Central Pacific, Station 270, depth 2925 fathoms. + + +6. _Gorgospyris liriope_, n. sp. (Pl. 87, fig. 6). + +Shell nut-shaped, thorny, with sharp sagittal stricture and irregular, +roundish pores. Two pairs of larger annular pores on each side of the ring. +Basal plate with two very large circular pores only. Eight to ten short +feet vertical, about one-fourth as long as the shell, with an elegant +papillate knob at the distal end. + +_Dimensions._--Shell 0.07 long, 0.1 broad; feet 0.02 long. + +_Habitat._--South Atlantic, Station 323, depth 1900 fathoms. + + +7. _Gorgospyris lamellosa_, n. sp. + +Shell nut-shaped, tuberculate, with subregular circular pores. Basal plate +with four larger and four alternate pairs of smaller pores. Feet fifteen to +twenty-five, broad, lamellar, vertical, truncate, about as long as the +shell, of irregular size and form, very variable. + +_Dimensions._--Shell 0.07 long, 0.1 broad; feet 0.05 to 0.1 long. + +_Habitat._--Fossil in Barbados. + + + +Subgenus 2. _Thamnospyris_, Haeckel, 1881, Prodromus, p. 443. + +_Definition._--Feet divided or branched. + + +8. _Gorgospyris schizopodia_, n. sp. (Pl. 87, fig. 4). + +Shell hemispherical, smooth, with slight sagittal stricture and small +regular, circular pores. Basal plate with four large central and a circle +of small pores. Feet fifteen to twenty, broad, lamellar, confluent at the +base, about as long as the shell, irregularly divided or forked. + +_Dimensions._--Shell 0.06 long, 0.08 broad; feet 0.05 to 0.08 long. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +9. _Gorgospyris thamnopodia_, n. sp. + + _Thamnospyris thamnopodia_, Haeckel, 1881, Prodromus, p. 143. + +Shell nut-shaped, tuberculate, with deep sagittal stricture and irregular, +roundish pores. Basal plate with numerous small pores. Feet twenty to +thirty, slender, curved, divergent, twice to three times as long as the +shell, irregularly branched. + +_Dimensions._--Shell 0.08 long, 0.12 broad; feet 0.15 to 0.25 long. + +_Habitat._--Indian Ocean (Madagascar), Rabbe, surface. + + + +{1072}Subfamily 8. CIRCOSPYRIDA, Haeckel, 1881, Prodromus, p. 443. + +_Definition._--#Zygospyrida# apoda, without descending basal feet. + + + +Genus 467. _Circospyris_,[85] Haeckel, 1881, Prodromus, p. 444. + +_Definition._--#Zygospyrida# without basal feet, with an apical horn. + +The genus _Circospyris_ and the following closely allied genus +_Dictyospyris_ represent together the small subfamily Circospyrida, +differing from all other Zygospyrida in the absence of feet on the basal +face. They have probably arisen from the Tripospyrida (_Tripospyris_) by +reduction and loss of the feet (in the same way as the eradiate #Cyrtoidea# +from the triradiate). But it is also possible that many of the Circospyrida +(if not all) are derived directly from the Semantida (_Clathrocircus_) by +the closing of the two lateral openings and by completing the framework. + + +1. _Circospyris nucula_, n. sp. (Pl. 95, fig. 13). + +Shell nut-shaped, compressed, smooth, with prominent sagittal ring. On each +side of the ring three to four pairs of very large annular polygonal pores. +Lateral pores small and numerous, roundish. Basal plate with two large +pores only. Horn slender, conical, shorter than half the shell. + +_Dimensions._--Shell 0.11 long, 0.13 broad. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + +2. _Circospyris gigas_, Haeckel. + + _Dictyospyris gigas_, Ehrenberg, Abhandl. d. k. Akad. d. Wiss. Berlin, p. + 68, Taf. xix. fig. 6. + +Shell nut-shaped, tuberculate, with distinct sagittal stricture. On each +side of the ring four pairs of larger annular pores. Lateral pores +roundish, smaller. Basal plate with four large central and a circle of +eight to twelve smaller peripheral pores. Horn cylindrical, about half as +long as the shell (in the inverted figure of Ehrenberg directed downwards). + +_Dimensions._--Shell 0.1 to 0.15 long, 0.15 to 0.2 broad; horn 0.05 to 0.08 +long. + +_Habitat._--Fossil in Barbados. + + +3. _Circospyris tridentata_, Haeckel. + + _Dictyospyris tridentata_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 70, Taf. xix. fig. 10, _a_, _b_. + +Shell nut-shaped, smooth, with sharp sagittal stricture. On each side of +the ring two pairs of large annular pores. Lateral pores roundish, smaller. +Basal plate with six large pores. Horn slender, cylindrical, about as long +as the shell, with three sharp teeth at the distal end. + +_Dimensions._--Shell 0.03 long, 0.05 broad; horn 0.03 long. + +_Habitat._--Fossil in Barbados. + + + +{1073}Genus 468. _Dictyospyris_,[86] Ehrenberg, 1847, Monatsber. d. k. +preuss. Akad. d. Wiss. Berlin, p. 54. + +_Definition._--#Zygospyrida# without basal feet, and without coryphal +horns. + +The genus _Dictyospyris_, the last and simplest of the twenty-eight genera +of Zygocyrtida, may be regarded either as a primordial ancestral form of +this large family, or more probably as the last and most reduced form of +it. In the former case the total absence of coryphal horns and basal feet +is primary, in the latter case secondary, effected by phylogenetic +reduction and loss. But it is also possible that in one part of the +numerous species of this genus the former case, and in another the latter +takes place, and that one part of _Dictyospyris_ may be directly developed +from the Semantida or Coronida (the lattice shell becoming complete), +another part arising from the Tripospyrida or Dipospyrida (the horns and +feet becoming lost). + + + +Subgenus 1. _Dictyospyrantha_, Haeckel. + +_Definition._--Basal plate with two large pores only (the primary jugular +pores of _Semantis_). + + +1. _Dictyospyris distoma_, n. sp. (Pl. 89, figs. 11, 12). + +Shell nut-shaped, smooth, or somewhat tuberculate, with deep sagittal +stricture. Pores not numerous, large, roundish-polygonal; three pairs of +large annular pores on each side of the ring. Basal plate with two very +large pentagonal roundish collar pores. + +_Dimensions._--Shell 0.06 long, 0.08 broad. + +_Habitat._--Central Pacific, Stations 265 to 268, depth 2700 to 2900 +fathoms. + + +2. _Dictyospyris stalactites_, n. sp. (Pl. 89, fig. 7). + +Shell nut-shaped, covered with irregular ramified tubercles (like +stalactites), with deep sagittal stricture. Pores not numerous, large, +irregular, roundish. Two pairs of large triangular pores on each side of +the ring (the inferior larger). Basal plate with two very large +semicircular collar pores. + +_Dimensions._--Shell 0.07 long, 0.09 broad. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms; also fossil +in Barbados. + + +{1074}3. _Dictyospyris biloba_, n. sp. + +Shell subspherical, tuberculate, with slight sagittal stricture. Pores very +numerous, small, circular. No larger pores on either side of the ring. +Basal plate with two very large circular pores, surrounded by a circle of +smaller pores. + +_Dimensions._--Shell 0.07 long, 0.08 broad. + +_Habitat._--North Pacific, Station 253, depth 3125 fathoms. + + + +Subgenus 2. _Dictyospyrella_, Haeckel. + +_Definition._--Basal plate with three large collar pores (two paired +posterior cardinal pores and an odd anterior sternal pore). + + +4. _Dictyospyris triomma_, n. sp. + +Shell nut-shaped, smooth, with deep sagittal stricture. Pores not numerous, +large, polygonal roundish, two pairs of very large annular pores on each +side of the ring. Basal plate with three large triangular pores. No free +internal procolumella. + +_Dimensions._--Shell 0.06 long, 0.09 broad. + +_Habitat._--Indian Ocean, Zanzibar (Pullen), depth 2200 fathoms. + + +5. _Dictyospyris tristoma_, Ehrenberg. + + _Dictyospyris tristoma_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 70, Taf. xix. fig. 9. + +Shell nut-shaped, tuberculate, with slight sagittal stricture. Pores +numerous, irregular, roundish. Three pairs of larger annular pores on each +side of the ring. Basal plate with three large semi-circular pores (the +sternal odd pore apparently halved by an internal free procolumella). + +_Dimensions._--Shell 0.05 long, 0.08 broad. + +_Habitat._--Fossil in Barbados and Sicily (Caltanisetta). + + +6. _Dictyospyris triloba_, Ehrenberg. + + _Dictyospyris triloba_, Ehrenberg, 1876, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 70, Taf. xix. fig. 8. + +Shell nut-shaped, spinulate, without external stricture, but with a +complete internal sagittal ring. Pores numerous, subregular circular; no +larger annular pores. Basal plate with three large, heart-shaped two-lobed +collar pores. + +_Dimensions._--Shell 0.05 long, 0.07 broad. + +_Habitat._--Fossil in Barbados. + + +{1075}7. _Dictyospyris gigas_, Buetschli. + + _Dictyospyris gigas_, Buetschli, 1880, Zeitschr. f. wiss. Zool., vol. + xxxvi., p. 539, Taf. xxxii. fig. 14_a_, 14_b_. + +Shell subspherical, smooth, with a half (ventral) sagittal stricture, and a +nearly complete internal ring. Pores very numerous and small, circular. No +larger annular pores. Basal plate with three large collar pores (the +sternal odd pore apparently divided into two jugular pores by the visible +free procolumella.) (Compare _Circospyris gigas_, p. 1072 = _Dictyospyris +gigas_, Ehrenberg). + +_Dimensions._--Shell 0.1 long, 0.14 broad. + +_Habitat._--Fossil in Barbados. + + + +Subgenus 3. _Dictyospyrissa_, Haeckel. + +_Definition._--Basal plate with four large collar pores (two larger +posterior cardinal and two smaller anterior jugular pores). + + +8. _Dictyospyris fenestra_, Ehrenberg. + + Dictyospyris fenestra, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 68, Taf. xix. fig. 11. + +Shell nearly cubical, smooth, without external sagittal stricture. Internal +sagittal ring complete. Pores small, roundish; on each side of the ring two +crossed pairs of large, square, equal, annular pores. Basal plate also with +four longer pores of nearly equal size. + +_Dimensions._--Shell 0.05 long, 0.07 broad. + +_Habitat._--Fossil in Barbados. + + +9. _Dictyospyris tetrastoma_, Ehrenberg. + + _Dictyospyris tetrastoma_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 70, Taf. xix. fig. 12. + +Shell nut-shaped, tuberculate, with slight sagittal stricture. Pores +numerous, irregular, roundish. No larger annular pores. Basal plate with +four large ovate collar pores (the two cardinal twice as large as the two +jugular pores). + +_Dimensions._--Shell 0.05 long, 0.07 broad. + +_Habitat._--Cosmopolitan; Atlantic, Indian, Pacific; also fossil in +Barbados and Sicily. + + +10. _Dictyospyris spinulosa_, Ehrenberg. + + Dictyospyris spinulosa, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 70, Taf. xix. fig. 13. + + ? _Ceratospyris borealis_, Bailey, 1856, Amer. Journ. of Science and + Arts, vol. xxii. pl. i. fig. 3. + +Shell nut-shaped, spinulate, without external stricture, with an internal +free sagittal ring. Pores numerous, irregular, roundish; on each side of +the ring two pairs of very large square pores. Basal plate with four large +collar pores. + +{1076}_Dimensions._--Shell 0.07 long, 0.08 broad. + +_Habitat._--Central Pacific, Stations 271 to 274, depth 2350 to 2750 +fathoms; also fossil in Barbados. + + +11. _Dictyospyris mammillaris_, n. sp. (Pl. 89, figs. 9, 10). + +Shell mammillate, nut-shaped, with deep sagittal stricture. Mammillae of +the surface hemispherical, with a conical apex. Pores not numerous, large, +roundish. Two pairs of large pores on each side of the ring. Basal plate +with four large pores. + +_Dimensions._--Shell 0.06 long, 0.08 broad. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +12. _Dictyospyris anthophora_, n. sp. (Pl. 89, fig. 8). + +Shell tuberculate, nut-shaped, nearly cubical, without external sagittal +strictures. Pores not numerous, large, polygonally roundish. Bars between +them compressed, elevated, with large, campanulate or flower-like tubercles +on the nodal points. Basal plate with four large pores. + +_Dimensions._--Shell 0.07 long, 0.09 broad. + +_Habitat._--North Atlantic, Station 349, depth 2450 fathoms. + + +13. _Dictyospyris quadriloba_, n. sp. + +Shell nut-shaped, smooth, with deep sagittal stricture. Pores numerous, +small, circular, on each side of the ring three to four times as large as +on the lateral sides. Basal plate with four very large collar pores and a +circle of twenty to twenty-five very small peripheral pores. + +_Dimensions._--Shell 0.08 long, 0.11 broad. + +_Habitat._--Central Pacific, Stations 270 to 274, depth 2350 to 2925 +fathoms. + + +14. _Dictyospyris messanensis_, J. Mueller. + + _Dictyospyris messanensis_, J. Mueller, 1858, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 46, Taf. ii. fig. 8. + + _Dictyospyris messanensis_, Haeckel, 1862, Monogr. d. Radiol., p. 291. + +Shell nut-shaped, spinulate, with deep sagittal stricture. Pores numerous +and small, irregular roundish. No larger annular pores on the sides of the +ring. Basal plate with four large, nearly equal, pear-shaped collar pores. + +_Dimensions._--Shell 0.06 long, 0.08 broad. + +_Habitat._--Mediterranean; Messina, surface. + + + +Subgenus 4. _Dictyospyromma_, Haeckel. + +_Definition._--Basal plate with six or more collar pores. + + +{1077}15. _Dictyospyris hexastoma_, n. sp. + +Shell nut-shaped, tuberculate, with deep sagittal stricture. Pores small, +irregular, roundish. Three pairs of larger pores on each side of the ring. +Basal plate with six large pores; the middle pair (cardinal) twice as large +as the anterior (jugular) and the posterior (cervical). + +_Dimensions._--Shell 0.08 long, 0.12 broad. + +_Habitat._--Fossil in Barbados. + + +16. _Dictyospyris enneastoma_, n. sp. + +Shell ellipsoidal, smooth, without external sagittal stricture, but with an +internal free sagittal ring. Pores small and numerous, regular, circular. +No larger annular pores. Basal plate with nine pores, three larger +interradial alternating with three pairs of adradial. + +_Dimensions._--Shell 0.07 long, 0.11 broad. + +_Habitat._--South Pacific, Station 297, depth 1775 fathoms. + + +17. _Dictyospyris polystoma_, n. sp. + +Shell nut-shaped, mammillate, with distinct sagittal stricture. Pores small +and numerous, irregular, on each side of the ring three to five times as +large as on the lateral sides. Basal plate with twelve large pores (four +central and four alternate pairs of peripheral). + +_Dimensions._--Shell 0.1 long, 0.14 broad. + +_Habitat._--Tropical Atlantic, Station 338, depth 1990 fathoms. + + + +Family LIII. #THOLOSPYRIDA#, n. fam. + +(Pl. 87, figs. 7-10; Pl. 89, figs. 1-4; Pl. 95, figs. 14-16). + +_Definition._--#Spyroidea# with a galea, but without thorax; the shell +being composed of the bilocular cephalis and of an aboral cupola or galea +arising from its coryphal face. + +The family #Tholospyrida# differs from the preceding Zygospyrida, its +ancestral group, in the development of a galea, _i.e._, a fenestrated +hemispherical or dome-shaped cupola, which covers the upper face of the +cephalis like a cap. + +Only three species of this family have been hitherto described: +_Pylospyris_ (or _Spyridobotrys_) _trinacria_, figured in my Monograph +(1862), _Pylospyris_ (or _Lithopera_) _denticulata_, figured by Ehrenberg +(1872), and _Lophospyris_ (or _Ceratospyris_) _acuminata_, figured by +Hertwig (1879). Fourteen new species have been found in the collection of +the Challenger, which we dispose here among five genera. These may be +derived from corresponding genera of Zygospyrida by the development of a +galea. + +{1078}The number and disposition of the terminal feet around the basal +plate do not vary so much in the Tholospyrida as in the Zygospyrida. We +find here only one genus with three feet, _Tholospyris_ (corresponding to +_Tripospyris_); one genus with two lateral feet, _Lophospyris_ +(corresponding to _Dipospyris_); and two genera with numerous feet, the +horned _Sepalospyris_ and the hornless _Tiarospyris_ (the former +corresponding to _Petalospyris_, the latter to _Gorgospyris_). The fifth +genus (_Pylospyris_) has no feet at all, and may be derived from +_Circospyris_ among the Zygospyrida. + +The cephalis exhibits in the Tholospyrida the same typical structure which +we have described above of all #Spyroidea# (compare p. 1017). The cupola or +galea, arising from its upper face, seems to be a secondary production, +perhaps caused by an apical growth of the central capsule, or in other +cases by descending branches of the apical horn, which cover the apical +face of the calymma with protecting network. + +_Synopsis of the Genera of Tholospyrida._ + + {Three basal feet (two + I. Subfamily Lophospyrida. { paired pectoral and + Two or three basal (cortinar{ an odd caudal), 469. _Tholospyris_. + feet). Galea with a horn. { + {Two paired basal + { (pectoral) feet, 470. _Lophospyris_. + + II. Subfamily Tiarospyrida. }Galea with a horn, 471. _Sepalospyris_. + Numerous basal feet in a } + corona (six to nine }Galea without a horn, 472. _Tiarospyris_. + or more). } + + III. Subfamily Pylospyrida. }Galea with a horn, 473. _Pylospyris_. + No basal feet. } + + + +Genus 469. _Tholospyris_,[87] Haeckel, 1881, Prodromus, p. 441. + +_Definition._--#Tholospyrida# with three basal feet and an apical horn. + +The genus _Tholospyris_ is probably the common ancestral form of the +Tholospyrida, and has arisen from _Tripospyris_ by development of a galea +or cupola; this is composed of the apical horn, the lateral branches of +which become connected with lateral spines arising from the coryphal face +of the cephalis, and of lattice-work developed between the former and the +latter. The three descending feet of the basal face are the typical +cortinar feet (one odd caudal and two paired pectoral), the same as in the +old ancestral genera _Cortina_, _Plagoniscus_, _Tripospyris_, &c. + + + +Subgenus 1. _Tholospyrium_, Haeckel. + +_Definition._--Basal feet simple, neither forked nor branched. + + +{1079}1. _Tholospyris tripodiscus_, n. sp. (Pl. 89, fig. 1). + +Shell campanulate, smooth, as broad as long, with deep sagittal stricture. +Cephalis compressed, with irregular roundish pores; two or three pairs of +larger annular pores on each side of the ring. Basal plate with four large +pores. Galea with two very large opposite holes (an occipital and a frontal +opening). A slender free perpendicular columella connects the uppermost +part of the sagittal ring with the strong three-sided pyramidal apical +horn. All three feet of equal length, half as long as the ring, +three-sided, prismatic, divergent, with three dentated edges. + +_Dimensions._--Shell 0.13 diameter, ring 0.08 long, feet 0.05 long. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +2. _Tholospyris fenestrata_, n. sp. (Pl. 89, fig. 2). + +Shell roundish polyhedral, smooth, with slight sagittal stricture. Cephalis +nearly cubical, with irregularly roundish pores; two or three pairs of +larger pores on each side of the ring. Basal plate with two very large +pores. Galea pyramidal, with two large occipital holes. Columella enclosed +in the dorsal wall of the galea, prolonged into an oblique pyramidal spine +of the same length. Two pectoral feet pyramidal, nearly vertical and as +long as the ring, twice as long as the caudal foot. + +_Dimensions._--Shell 0.12 diameter, ring 0.07, pectoral feet 0.05 long. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +3. _Tholospyris galeata_, n. sp. + +Shell helmet-shaped, thorny, with deep sagittal stricture. Cephalis +campanulate, with subregular circular pores. Basal plate with three large +pores. Galea hemispherical, separated from the cephalis by a sharp +horizontal stricture; pores smaller. A slender free columella connects the +apex of the ring with the strong conical apical horn, which is half as long +as the ring. All three feet of equal length, divergent conical, as long as +the horn. + +_Dimensions._--Shell 0.14 diameter, ring 0.09 long, feet 0.08 long. + +_Habitat._--Central Pacific, Station 263, depth 2650 fathoms. + + + +Subgenus 2. _Tholospyridium_, Haeckel. + +_Definition._--Basal feet forked or branched. + + +4. _Tholospyris ramosa_, n. sp. (Pl. 89, fig. 3). + +Shell helmet-shaped, smooth, with deep sagittal stricture. Cephalis nearly +spherical, with irregularly polygonal pores; four or five pairs of larger +annular pores on each side of the strong angular ring. Cupola flat, +conical, with two pairs of larger pores. Columella enclosed in its dorsal +wall, {1080}bearing an irregularly branched horn. Caudal foot short +conical, simple. Two pectoral feet half as long as the shell, angular, +subvertical, irregularly branched. + +_Dimensions._--Shell 0.15 diameter, ring 0.1 long, pectoral feet 0.07 long. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +5. _Tholospyris cupola_, n. sp. (Pl. 89, fig. 4). + +Shell pear-shaped or cupola-shaped, smooth, with slight sagittal stricture. +Cephalis not distinctly separated from the galea, as the ring in the +uppermost part of the shell-wall becomes obliterated. Pores irregularly +polygonal, small and numerous. Basal plate with four large pores. Apical +horn and the three divergent feet, irregularly branched; feet nearly as +long as the shell, about four times as long as the horn. + +_Dimensions._--Shell 0.14 diameter, ring 0.1 long, feet 0.12 long. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + + +Genus 470. _Lophospyris_,[88] Haeckel, 1881, Prodromus, p. 443 (_sensu +emendato_). + +_Definition._--#Tholospyrida# with two lateral basal feet and an apical +horn. + +The genus _Lophospyris_ differs from the preceding _Tholospyris_, its +probable ancestral form, in the absence of the caudal foot, and therefore +bears to it the same relation that _Dipospyris_ does to _Tripospyris_. The +two pectoral feet are alone developed and are placed opposite in the +frontal plane. _Lophospyris_ may also be derived from _Dipospyris_ by the +formation of a galea. + + +1. _Lophospyris dipodiscus_, n. sp. (Pl. 95, fig. 14). + +Shell ovate, spinulate, with sharp transverse coronal constriction. Cupola +hemispherical, half as large as the nut-shaped cephalis. Pores irregularly +roundish, much larger on the sagittal constriction. Apical horn pyramidal, +about half as long as the shell. Two lateral feet cylindrical, strongly +curved, about as long as the shell, with some irregular branches; together +forming a nearly complete circle. + +_Dimensions._--Shell 0.09 long, 0.08 broad; ring 0.04 long, feet 0.08 long. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +2. _Lophospyris acuminata_, Haeckel. + + _Ceratospyris acuminata_, R. Hertwig, 1879, Organism. d. Radiol., p. 70, + Taf. vii. fig. 2. + +Shell campanulate, smooth, without external transverse stricture. Cupola +conical, half as long and broad as the nut-shaped cephalis. Pores +irregularly roundish, on each side of the sagittal {1081}strictures much +larger. Basal plate with four large triangular pores. Apical horn slender, +prismatic; its outer free part of the same length as the inner columella, +and as the two lateral feet, which are curved, shorter than half the ring. + +_Dimensions._--Shell 0.08 long, 0.09 broad; ring 0.06 long; horn and feet +0.03 long. + +_Habitat._--Mediterranean, Messina (R. Hertwig). + + +3. _Lophospyris comosa_, n. sp. + +Shell ovate, spiny, with deep transverse stricture. Cupola large, +campanulate, nearly as long and two-thirds as broad as the nut-shaped +cephalis. Pores irregular, roundish, of little different size, Basal plate +with numerous (eight to twelve) similar pores. Apical horn large, nearly as +long as the shell, surrounded by a bunch of smaller divergent spines. Two +lateral feet divergent, larger than the shell, cylindrical; at the distal +end irregularly branched, at the base surrounded by some smaller spines. + +_Dimensions._--Shell 0.15 long, 0.11 broad; ring 0.08 long; feet 0.2 long. + +_Habitat._--Western Tropical Pacific, Station 206, depth 2100 fathoms. + + + +Genus 471. _Sepalospyris_,[89] Haeckel, 1881, Prodromus, p. 443. + +_Definition._--#Tholospyrida# with numerous basal feet (eight to twelve or +more). Galea with a horn. + +The genus _Sepalospyris_ has been derived from the similar _Petalospyris_ +by development of a galea or cupola on the coryphal face of the cephalis, +or from _Tholospyris_ by multiplication of the basal feet. The latter (in +the two observed species from twelve to twenty-five) form a regular corona +around the basal plate. + + +1. _Sepalospyris platyphylla_, n. sp. Pl. 95, fig. 15. + +Shell ovate, rough, with sharp transverse stricture. Cupola with delicate +network, hemispherical, about two-thirds as long and broad as the +nut-shaped thorax. Pores of the latter irregular, roundish; two or three +pairs of large pores on each side of the sagittal stricture. Apical horn +conical, half as long as the shell. Basal coronet with twelve to fifteen +broad, lamellar, truncate, vertical feet, somewhat shorter than the +cephalis. + +_Dimensions._--Shell 0.12 long, 0.13 broad; ring 0.06 long; horn 0.04; feet +0.05 long. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +2. _Sepalospyris polyphylla_, n. sp. + +Shell campanulate, rough, with deep transverse stricture. Cupola +hemispherical, about one-third as long and broad as the nut-shaped thorax. +Pores irregular, roundish, a little different in {1082}size. Apical horn +pyramidal, about as long an the shell. Basal coronet with twenty to +twenty-five slender, lamellar, pointed, vertical feet, longer than the +shell. + +_Dimensions._--Shell 0.11 long, 0.12 broad; ring 0.07 long; horn 0.1; feet +0.12 to 0.18 long. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + + +Genus 472. _Tiarospyris_,[90] Haeckel, 1881, Prodromus, p. 443. + +_Definition._--#Tholospyrida# with numerous basal feet (eight to twelve or +more). Galea without a horn. + +The genus _Tiarospyris_ has probably been derived from the preceding +_Sepalospyris_ by reduction and loss of the free apical horn; it therefore +bears to it the same relation that the similar _Gorgospyris_ does to +_Petalospyris_. + + +1. _Tiarospyris pervia_, n. sp. (Pl. 87, fig. 7). + +Shell nut-shaped, smooth, with deep sagittal stricture. Cephalis on the +lateral sides with numerous small roundish pores, on each side of the ring +with a pair of very large holes. Basal plate with two large collar pores. +Cupola flat, cap-shaped, with two large parietal pores above the ring. +Coronet with eight conical, slightly divergent feet, about one-fourth as +long as the shell. + +_Dimensions._--Shell 0.08 long, 0.1 broad; ring 0.06 long; feet 0.02 long. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +2. _Tiarospyris galea_, n. sp. + +Shell helmet-shaped, with deep sagittal stricture. Cephalis with irregular, +polygonal pores; on each side of the ring two pairs of larger annular +pores. Basal plate with four large pores. Cupola high, conical, nearly as +long as the cephalis, separated from it by a distinct coronal stricture. +Basal coronet with twelve to sixteen slender curved divergent feet, nearly +as long as the shell. + +_Dimensions._--Shell 0.16 long, 0.12 broad; ring 0.1 long; feet 0.15 long. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +3. _Tiarospyris mitra_, n. sp. (Pl. 87, figs. 9, 10). + +Shell subspherical, smooth. Cephalis on the lateral sides with small +roundish, double-contoured pores, on each side of the ring with three to +five pairs of larger pores, each of which is closed by a thin fenestrated +lamella (different on the frontal face, fig. 9, and the dorsal face, fig. +10). Cupola flat, cap-shaped, separated by a distinct coronal stricture, +with similar pores. Basal coronet with, ten to twelve short conical +convergent feet. + +_Dimensions._--Shell 0.11 long, 0.12 broad; ring 0.04 long; feet 0.02 long. + +_Habitat._--West Tropical Pacific, Station 225, depth 4475 fathoms. + + +{1083}4. _Tiarospyris amphora_, n. sp. (Pl. 87, fig. 8). + +Shell amphora-shaped, in the upper half smooth, in the lower spiny, without +external sagittal stricture. Cephalis subspherical with a small number of +irregular, large, roundish pores, which are closed by a thin fenestrated +lamella. Cupola flat, cap-shaped, with numerous small pores. Base covered +with numerous conical divergent feet of different sizes, the largest +one-third as long as the shell. Internal sagittal ring ovate, nearly free. + +_Dimensions._--Shell 0.14 long, 0.13 broad; ring 0.1 long; feet 0.04 long. + +_Habitat._--South Pacific, Station 285, depth 2375 fathoms. + + + +Genus 473. _Pylospyris_,[91] Haeckel, 1881 Prodromus, p. 443. + +_Definition._--#Tholospyrida# without basal feet, with an apical horn. + +The genus _Pylospyris_ was first known from a Mediterranean species, called +by me, in 1862, _Spyridobotrys trinacria_. As this name was given +erroneously, on the supposition of a near relation to the Botryodea (= +Polycyrtida), I changed it afterwards to _Pylospyris_. This genus differs +from the other Tholospyrida in the total absence of basal feet, and may +therefore be derived either from them by reduction of the feet, or from +_Dictyospyris_ by formation of a galea. + + +1. _Pylospyris denticulata_, Haeckel. + + _Lithopera denticulata_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 297, Taf. xii. II. fig. 7. + + _Lithobotrys denticulata_, Ehrenberg, 1844, Monatsber. d. Akad. Berlin, + p. 203. + +Shell spinulate, with slight coronal and deep sagittal constriction, with +irregular, roundish pores of variable size. Galea hemispherical, about half +as long and broad as the nut-shaped cephalis. No symmetrically disposed +larger pores. + +_Dimensions._--Galea 0.04 long, 0.06 broad; cephalis 0.08 long, 0.1 broad. + +_Habitat._--Antarctic Ocean, Ehrenberg. (Included in the ice.) + + +2. _Pylospyris trinacria_, Haeckel. + + _Spyridobotrys trinacria_, Haeckel, 1862, Monogr. d. Radiol., p. 341, + Taf. xii. figs. 8, 9. + +Shell tuberculate, with sharp coronal and sagittal stricture. Galea +campanulate, with very small circular pores, and a short conical apical +horn of the same length. Cephalis nut-shaped, with large, irregular, +roundish pores; two pairs of larger annular pores on each side of the +sagittal ring, also four larger pores in the basal plate. + +_Dimensions._--Galea 0.03 long, 0.04 broad; cephalis 0.04 long, 0.07 broad. + +_Habitat._--Mediterranean, Messina, surface. + + +{1084}3. _Pylospyris canariensis_, n. sp. (Pl. 95, fig. 16). + +Shell rough, with deep coronal and slight sagittal constriction. Galea +hemispherical, with numerous small irregular, roundish pores, about half as +long as the cephalis, with a slender conical horn of twice the length. +Cephalis nut-shaped, with larger roundish pores of very unequal size, three +pairs of larger pores on each side of the ring. Basal plate with two larger +pores. + +_Dimensions._--Galea 0.03 long, 0.08 broad; cephalis 0.06 long, 0.11 broad. + +_Habitat._--North Atlantic, Canary Islands, surface. + + + +Family LIV. #PHORMOSPYRIDA#, Haeckel (_sensu emendato_) (Pl. 83, figs. +13-15; Pl. 95, figs. 17-19). + + _Phormospyrida_, Haeckel, 1881, Prodromus, p. 442. + +_Definition._--#Spyroidea# with a thorax, without galea; the shell composed +of the bilocular cephalis and of a simple thorax arising from its basal +face. + +The family #Phormospyrida# differs from the Zygospyrida, their ancestral +group, in the development of a thorax, or a second fenestrated shell-joint, +which arises from the lower face of the cephalis. It corresponds, +therefore, to the Dicyrtida among the #Cyrtoidea#, and may perhaps be, +wholly or partially, the ancestral group of the latter. When the sagittal +ring and the longitudinal constriction of the cephalis disappear, the +Phormospyrida pass over into the Dicyrtida. + +Only three species of this family have been hitherto known, which were +found fossil in Barbados, and described by Ehrenberg (1875) as _Lithobotrys +stiligera_ and _Petalospyris confluens_, and by Buetschli (1882) as +_Petalospyris anthocyrtoides_. Fifteen other species are found in the +Challenger collection, which we dispose here among five genera. + +Two of these five genera (the horned _Acrospyris_ and the hornless +_Phormospyris_) possess the three typical basal feet of _Cortina_ and +_Tripospyris_, and may be derived from these genera by the development of +network between the bases of the feet. The three other genera possess +numerous feet, and may be derived in the same way from the Polyspyrida; the +apical face differs in the three genera, in _Desmospyris_ it is hornless, +in _Patagospyris_ it bears an apical horn, and in Rhodospyris three horns +(an apical and two lateral or frontal). + +The cephalis in the Phormospyrida exhibits the same typical structure, +which we have described above, of all #Spyroidea# (compare, p. 1017). The +thorax or the second joint of the shell arises by reticular connection of +the bases of the basal feet, and represents a cylindrical or +truncate-conical joint in the polypodal forms, or a three-sided joint in +the tripodal forms. The terminal aperture or the mouth of the thorax is +constantly open, and surrounded by the free ends of the feet. + +{1085}_Synopsis of the Genera of Phormospyrida._ + + I. Subfamily Acrospyrida. } + } One apical horn, 474. _Acrospyris_. + Three basal cortinar feet } + (one odd caudal and two } No apical horn, 475. _Phormospyris_. + paired pectoral). } + + II. Subfamily Rhodospyrida. { One apical horn, 476. _Patagospyris_. + { + Numerous basal feet in a { Three apical horns, 477. _Rhodospyris_. + corona (nine to twelve or { + ore.) { No apical horn, 478. _Desmospyris_. + + + +Subfamily 1. ACROSPYRIDA, Haeckel, 1881, Prodromus, p. 441 (_sensu +emendato_). + +_Definition._--#Phormospyrida# with three basal feet (an odd caudal and two +paired pectoral). + + + +Genus 474. _Acrospyris_,[92] Haeckel, 1881, Prodromus, p. 441. + +_Definition._--#Phormospyrida# with three basal feet and one apical horn. + +The genus _Acrospyris_ is probably the oldest and most primitive among the +Phormospyrida, perhaps the original ancestral form of this family. It has +been derived from _Tripospyris_ by the development of lattice-work between +the three basal feet, forming a second joint or thorax. It has also +therefore a close relation to the simplest forms of the triradiate +Dicyrtida: _Dictyophimus_, _Clathrocanium_, &c. It differs from these in +the distinct sagittal constriction of the cephalis, which divides it into +two lateral loculi. + + +1. _Acrospyris clathrocanium_, n. sp. (Pl. 95, fig. 17). + +Shell tuberculate, with distinct collar and deep sagittal stricture. +Cephalis nut-shaped, with numerous irregular, roundish pores; three pairs +of larger annular pores on each side of the ring. Basal plate with four +larger pores (two major cardinal and two minor jugular pores). Apical horn +slender, pyramidal, curved, about as long as the shell, with three recurved +short spines. Thorax three-sided, about twice as large as the cephalis, +with three large basal holes and a broad riband with numerous smaller +holes; three ribs between them stout, pyramidal, strongly curved, prolonged +into three convergent crescentic feet. + +_Dimensions._--Cephalis 0.08 long, 0.11 broad; thorax 0.14 long, 0.16 +broad. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +2. _Acrospyris dictyophimus_, n. sp. + +Shell smooth. Cephalis and thorax of nearly the same structure and form as +in the preceding species; it differs from the latter in the shape of the +three stout basal feet, which are {1086}straight, much longer than the +thorax, divergent, and at the broader base irregularly fenestrated, without +three larger holes. + +_Dimensions._--Cephalis 0.05 long, 0.08 broad; thorax 0.07 long, 0.12 +broad. + +_Habitat._--North Pacific, Station 241, depth 2300 fathoms. + + +3. _Acrospyris pyramidalis_, n. sp. + +Shell three-sided pyramidal, with slight collar stricture. Cephalis +campanulate, with deep sagittal stricture and stout ring, armed with a +strong pyramidal horn of the same length. Thorax shorter and broader, +truncate. Pores irregular, roundish, scarce. Three feet divergent, +three-sided pyramidal, as long as the cephalis. + +_Dimensions._--Cephalis 0.05 long, 0.06 broad; thorax 0.02 long, 0.08 +broad. + +_Habitat._--Fossil in Barbados. + + +4. _Acrospyris macrocephala_, n. sp. + +Shell spinulate, with deep sagittal and very deep collar stricture. +Cephalis very large, nut-shaped, twice as long and broad as the small, +truncate, pyramidal thorax. Pores irregular, roundish. Horn spindle-shaped, +nearly as long as the cephalis; the three divergent feet are of the same +form and size as the horn, and arise as three ribs from the deep collar +stricture. + +_Dimensions._--Cephalis 0.1 long, 0.15 broad; thorax 0.05 long, 0.09 broad. + +_Habitat._--Fossil in Barbados. + + +5. _Acrospyris fragilis_, n. sp. + +Shell very thin-walled and fragile, with deep sagittal and collar +strictures. Pores very small and numerous, circular. Cephalis nut-shaped, +nearly spherical, with a slender bristle-shaped horn of the same length. +Basal stricture with two large collar pores only (luminella). Thorax nearly +three-sided prismatic, longer than the cephalis, with three parallel ribs, +prolonged into three slender, long, bristle-shaped feet. + +_Dimensions._--Cephalis 0.05 long, 0.06 broad; thorax 0.08 long, 0.06 +broad. + +_Habitat._--North Pacific, Station 244, surface. + + + +Genus 475. _Phormospyris_,[93] Haeckel, 1881, Prodromus, p. 442 (_sensu +emendato_). + +_Definition._--#Phormospyrida# with three basal feet, without apical horn. + +The genus _Phormospyris_ has been derived from _Acrospyris_, its ancestral +form, by reduction and loss of the apical horn; it therefore bears to the +latter the same relation that _Tristylospyris_ has to the ancestral +_Tripospyris_. + + +{1087}1. _Phormospyris tricostata_, n. sp. (Pl. 83, fig. 15). + +Cephalis nut-shaped, thorny, with deep sagittal and collar strictures, half +as large as the pyramidal thorax. Mouth of the latter dilated and ciliated, +twice as broad as the cephalis. Pores irregular, polygonal, with thin bars. +Three cylindrical, straight, divergent ribs descend in the wall of the +thorax, and are prolonged over the mouth into three short conical teeth. + +_Dimensions._--Cephalis 0.06 long, 0.09 broad; thorns 0.08 long, 0.16 +broad. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +2. _Phormospyris tridentata_, n. sp. (Pl. 95, fig. 18). + +Cephalis nut-shaped, with deep sagittal and collar strictures, about twice +as large as the thorax. Mouth of the latter half as broad as the cephalis. +Pores very small and numerous, subregular, circular. Collar plate with four +large triangular pores. In the wall of the thorax three vertical prismatic +ribs descend, which are prolonged over the mouth into three parallel feet +of the same length. + +_Dimensions._--Cephalis 0.06 long, 0.08 broad; thorns 0.04 long, 0.06 +broad. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + +3. _Phormospyris trifoliata_, n. sp. + +Cephalis nut-shaped, with deep sagittal and collar strictures, smaller than +the thorax. Mouth of the latter nearly as broad as the cephalis. Pores +circular, double-contoured, larger in the thorax than in the cephalis. The +thorax has no lateral ribs, but bears around the mouth three large +triangular lamellar terminal feet. + +_Dimensions._--Cephalis 0.04 long, 0.05 broad; thorax 0.06 long, 0.05 +broad. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +Subfamily 2. RHODOSPYRIDA, Haeckel. + +_Definition._--#Phormospyrida# with a corona of numerous (nine to twelve or +more) basal feet. + + + +Genus 476. _Patagospyris_,[94] Haeckel, 1881, Prodromus, p. 443. + +_Definition._--#Phormospyrida# with numerous basal feet (nine to twelve or +more) and an apical horn. + +The genus _Patagospyris_ and the two following closely allied genera differ +from the two preceding tripodal genera in the multiplication of the basal +feet, and therefore have to the latter the same relation that the +Polyspyrida (_Petalospyris_) bear to the Tripospyrida (_Tripospyris_). When +the numerous basal feet of _Petalospyris_ become connected by lattice-work, +_Patagospyris_ arises. + + +{1088}1. _Patagospyris confluens_, Haeckel. + + _Petalospyris confluens_, Ehrenberg, 1885, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 80, Taf. xxii. fig. 5. + +Shell tuberculate, with distinct sagittal and collar strictures. Pores +irregular, roundish. Cephalis nut-shaped, larger than the short truncate +thorax. Horn conical, shorter than the cephalis. Peristome with a coronet +of twelve to fifteen short triangular feet, which are parallel and +vertical, slightly curved and shorter than the thorax. + +_Dimensions._--Cephalis 0.05 long, 0.07 broad; thorax 0.03 long, 0.07 +broad. + +_Habitat._--Fossil in Barbadoes. + + +2. _Patagospyris lanceolata_, n. sp. + +Shell tuberculate, with slight sagittal and sharp collar strictures. Pores +subregular, circular. Cephalis subspherical, about as large as the truncate +subcylindrical thorax. Horn spindle-shaped, about as long as the cephalis. +Peristome with a coronet of fifteen to twenty divergent lanceolate lamellar +feet, longer than the thorax. + +_Dimensions._--Cephalis 0.08 long, 0.09 broad; thorax 0.07 long, 0.07 +broad. + +_Habitat._--Fossil in Barbados. + + +3. _Patagospyris stiligera_, Haeckel. + + _Lithobotrys stiligera_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 76, Taf. iii. fig. 17. + +Shell smooth, hyaline, with deep sagittal and collar strictures. Pores very +small and few. Cephalis nut-shaped, bilobed, of the same breadth as the +cylindrical thorax. Horn conical, about as long as the cephalis. Peristome +with a coronet of six to nine broad lamellar feet (in Ehrenberg's figure +broken off). + +_Dimensions._--Cephalis 0.04 to 0.05 diameter; thorax 0.06 long, 0.05 +broad. + +_Habitat._--Fossil in Barbados. + + +4. _Patagospyris anthocyrtis_, n. sp. (Pl. 95, fig. 19). + +Shell smooth, with deep sagittal and deep collar strictures. Pores +irregular, roundish, of various sizes, numerous. Cephalis nut-shaped, with +two inflated bosoms, about twice as broad as the short cylindrical thorax. +Horn stout, pyramidal, about as long as the cephalis. Peristome with a +coronet of fifteen to twenty parallel and vertical triangular lamellar +feet, nearly as long as the thorax. + +_Dimensions._--Cephalis 0.05 long, 0.1 broad; thorax 0.04 long, 0.06 broad. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + + +Genus 477. _Rhodospyris_,[95] Haeckel, 1881, Prodromus, p. 443. + +_Definition._--#Phormospyrida# with numerous basal feet (nine to twelve or +more), and with three coryphal horns. + +{1089}The genus _Rhodospyris_ differs from the preceding _Patagospyris_ in +the development of three coryphal horns (one odd middle apical horn, and +two paired frontal horns on each of its sides), and therefore bears the +same relation to the latter that the similar _Anthospyris_ does to +_Petalospyris_. When the numerous basal feet of _Anthospyris_ become +connected by lattice-work, _Rhodospyris_ arises. + + +1. _Rhodospyris tricornis_, n. sp. (Pl. 83, fig. 13). + +Cephalis nut-shaped, with deep sagittal stricture, and three short apical +horns of half its length; the middle odd horn is straight, the two paired +lateral horns are curved outwards. Thorax somewhat larger than the +cephalis, dilated around the wide open mouth, with a coronet of twenty-five +to thirty slender basal feet, which are slightly curved and convergent, +about as long as the thorax. Pores small, numerous and circular. + +_Dimensions._--Cephalis 0.05 long, 0.07 broad; thorax 0.06 long, 0.08 +broad; horns 0.02 long, feet 0.06 long. + +_Habitat._--Indian Ocean, Madagascar (Rabbe), surface. + + +2. _Rhodospyris triceros_, n. sp. + +Cephalis nut-shaped, with deep sagittal and deep collar stricture, and with +three stout divergent horns of nearly equal length. Thorax cylindrical, +twice as long as the cephalis, and of the same breadth, with a coronet of +twelve to sixteen broad, lamellar, rectangular, perpendicular feet around +the mouth, about as long as the cephalis. Pores rather large, subregular, +circular. + +_Dimensions._--Cephalis 0.06 long, 0.08 broad; thorax 0.12 long, 0.09 +broad. + +_Habitat._--Indian Ocean, Singapore (Trebing), surface. + + + +Genus 478. _Desmospyris_,[96] Haeckel, 1881, Prodromus, p. 443. + +_Definition._--#Phormospyrida# with numerous basal feet (nine to twelve or +more), without a coryphal horn. + +The genus _Desmospyris_ differs from the two preceding polypodal genera in +the complete absence of horns on the coryphal face of the cephalis. It +therefore corresponds to _Gorgospyris_ among the Zygocyrtida, and arises +when the numerous basal feet of the latter become connected by +lattice-work. + + +1. _Desmospyris mammillata_, n. sp. (Pl. 83, fig. 14). + +Shell mammillate, with deep sagittal and slight collar constriction. Pores +irregular, roundish. Cephalis nut-shaped, larger than the inversely conical +thorax, and twice as broad as the constricted {1090}mouth. Coronet of the +peristome with twelve to fifteen short conical convergent feet, shorter +than half the thorax. + +_Dimensions._--Cephalis 0.06 long, 0.09 broad; thorax 0.04 long, 0.06 +broad. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +2. _Desmospyris cyrtocolpos_, n. sp. + +Shell smooth, with deep sagittal and collar strictures. Pores subregular, +circular, double-contoured, very small and numerous. Cephalis nut-shaped, +larger than the short truncate thorax. Coronet with eighteen to twenty-four +slender, irregular, pointed, convergent feet, about twice as long as the +thorax. + +_Dimensions._--Cephalis 0.08 long, 0.12 broad; thorax 0.04 long, 0.1 broad. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +3. _Desmospyris anthocyrtoides_, Haeckel. + + _Petalospyris anthocyrtoides_, Buetschli, 1882, Zeitschr. f. wiss. Zool., + vol. xxxvi. pp. 533, 539, Taf. xxxii. fig. 19, _a-c_. + +Shell tuberculate, with slight sagittal and sharp collar strictures. Pores +subregular, circular. Cephalis nut-shaped, larger than the short truncate +thorax. Coronet with fifteen to twenty short conical, parallel and vertical +feet, about as long as the thorax. + +_Dimensions._--Cephalis 0.06 long, 0.09 broad; thorax 0.02 long, 0.07 +broad. + +_Habitat._--Fossil in Barbados. + + +4. _Desmospyris carpocanium_, n. sp. + +Shell smooth, with slight sagittal and slight collar strictures. Pores +subregular, circular, small and numerous. Cephalis campanulate, smaller +than the ovate thorax. Coronet with fifteen to twenty irregular lamellar +feet, which are longer than the thorax, pointed, nearly vertical and +parallel. + +_Dimensions._--Cephalis 0.05 long, 0.08 broad; thorax 0.07 long, 0.1 broad. + +_Habitat._--South Pacific, Station 298, depth 2225 fathoms. + + + +Family LV. #ANDROSPYRIDA#, n. fam. (Pl. 88-90). + +_Definition._--#Spyroidea# with galea and thorax; the shell composed of a +bilocular cephalis and of two secondary joints, a galea arising from its +upper face, and a thorax arising from its lower face. + +{1091}The family #Androspyrida# differs from the three preceding families +of #Spyroidea# in the three-jointed shell, in which the galea of the +Tholospyrida and the thorax of the Phormospyrida are combined; it may +therefore be derived from the latter by development of a galea, or from the +former by formation of a thorax. The common ancestral group of these three +families is probably the Zygospyrida. But it may be that a part of the +Androspyrida has originated directly from the #Stephoidea#. + +Two species only of this family were hitherto known, _Amphispyris +reticulata_ (figured, in 1872, by Ehrenberg, as _Dictyospyris_) and +_Sphaerospyris sphaera_ (described, in 1882, by Buetschli, as +_Dictyospyris_). Thirty new species were found in the collection of the +Challenger, and are here disposed in seven genera. But perhaps these may +represent three different families, which we here enumerate as subfamilies; +the Lamprospyrida, Perispyrida, and Nephrospyrida. + +The Lamprospyrida, the first subfamily, are tripodal #Spyroidea# with galea +and thorax; they may therefore be regarded as a combination of +_Tholospyris_ and _Acrospyris_. In the simpler form, _Androspyris_ (Pl. 83, +fig. 8), the network of the shell is simple, and allows a very clear +recognition of the internal structure. In the splendid _Lamprospyris_, +derived from it (Pl. 89, figs. 13, 14) the delicate network is more or less +spongy. The large apical horn is branched and fenestrated in the latter and +simple in the former. + +The Perispyrida, the second subfamily, possess no free apophyses, but a +three-jointed shell with two distinct transverse strictures, an upper +mitral and a lower collar stricture. The network of this shell is +incomplete in _Amphispyris_ (Pl. 88, figs. 2-7), being developed only in +the frontal or lateral perimeter, thus making it probable that this +subfamily may have arisen directly from the Tympanida (_Toxarium_, Pl. 88, +fig. 1; Pl. 93, figs. 18-20). The network of _Tricolospyris_ (Pl. 88, figs. +8-11) is complete, of another shape in the cephalis than in the galea and +thorax; it is doubled or spongy in _Perispyris_ (Pl. 88, figs. 12, 13). + +The Nephrospyrida, the third subfamily, contains two very different genera +only, each of which may represent a separate family. _Sphaerospyris_ (Pl. +83, fig. 4) possesses a spherical or subspherical lattice-shell, the +central part of which includes a sagittal ring, connected with the inner +face of the sphere by a number of paired apophyses, corresponding to those +of _Lithocircus_; it may be easily confounded with some #Sphaeroidea# +(_Carposphaera_), but the enclosed ring leaves no doubt as to its true +origin. _Nephrospyris_ (Pl. 90) has a flat discoidal shell of considerable +size, usually kidney-shaped or cordate, with a deep sagittal incision at +the base, indicating the region where the pseudopodia are protruded from +the porochora. The violin-shaped central capsule has two large lateral +lobes on each side of the including sagittal ring, and the transverse +nucleus is perpendicular to its sagittal plane (Pl. 90, figs. 7, 10). +_Sphaerocircus_ as well as _Nephrospyris_ have probably arisen +independently from the Stephanida. + +{1092}_Synopsis of the Genera of Androspyrida._ + + ------------------------------------------------------------------------- + I. Subfamily Lamprospyrida. Three free basal feet. + ------------------------------------------------------------------------- + Lattice-work simple, not {Apical horn usually + spongy. { simple, not + { fenestrated, 479. _Androspyris_. + + Lattice-work wholly or {Apical horn usually + partly spongy. { branched and + { fenestrated, 480. _Lamprospyris_. + ------------------------------------------------------------------------- + II. Subfamily Perispyrida. No free basal feet. Shell three-jointed. + ------------------------------------------------------------------------- + {Lattice-work only + { complete in the + { frontal ring, 481. _Amphispyris_. + Shell with two transverse { + coronal strictures (one {Lattice-work complete + superior mitral and one { on all sides, 482. _Tricolospyris_. + inferior collar { + stricture). {Lattice-work double + { or spongy, 483. _Perispyris_. + + ------------------------------------------------------------------------- + III. Subfamily Nephrospyrida. + No free basal feet. Shell spherical or discoidal. + ------------------------------------------------------------------------- + {Shell spherical or + { subspherical, 484. _Sphaerospyris_. + Shell without external { + transverse stricture. {Shell discoidal, + { kidney-shaped or + { subcircular, 485. _Nephrospyris_. + + + +Subfamily 1. LAMPROSPYRIDA, Haeckel. + +_Definition._--#Androspyrida# with three free basal feet (an odd posterior +caudal foot and two paired anterior pectoral feet). + + + +Genus 479. _Androspyris_,[97] n. gen. + +_Definition._--#Androspyrida# with three free basal feet and a simple +apical horn; lattice-work of the three-jointed shell simple, not spongy. + +The genus _Androspyris_ is probably the most original form of the +Androspyrida, and represents, together with the following _Lamprospyris_, +the subfamily of Lamprospyrida, which always possess three free basal feet, +an odd posterior or caudal foot, and two paired anterior or pectoral feet. +It may be derived either from _Acrospyris_ by development of a cupola, or +from _Tholospyris_ by development of a thorax; the common ancestral form of +these three typical genera is, no doubt, _Tripospyris_. Some species of +_Androspyris_ reach a considerable size and are distinguished by a peculiar +external form resembling somewhat a human figure. + + +1. _Androspyris homunculus_, n. sp. + +Shell thorny, with two deep transverse constrictions and irregular +polygonal pores. Galea subspherical, with a strong pyramidal oblique horn, +about two-thirds as large as the cephalis, which has the form of a human +thorax, includes a strong ovate sagittal ring, and bears on each side a +stronger lateral spine. Thorax short and broad, prolonged into three +latticed divergent feet; the {1093}two lateral (pectoral) feet are like the +legs of a human body, and are twice as long as the cephalis and as the +tail-like caudal feet. (The whole shell exhibits a curious similarity to a +human figure, more than in the following nearly allied species.) + +_Dimensions._--Length of the shell (including horn and feet) 0.4, breadth +0.1 to 0.15. + +_Habitat._--Central Pacific, Station 273, depth 2350 fathoms. + + +2. _Androspyris anthropiscus_, n. sp. (Pl. 83, fig. 8). + +Shell rough, with two distinct transverse constrictions and irregular +polygonal pores. Galea ovate, with a slender conical oblique horn, about as +large as the cephalis, which exhibits a deep longitudinal furrow in the +sagittal dorsal line. Thorax half as long, prolonged into three short +latticed feet; the terminal spines of the two lateral feet are vertical and +parallel, that of the caudal foot larger, directed obliquely backwards. + +_Dimensions._--Length of the shell (including horn and feet) 0.35, breadth +0.1 to 0.12. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +3. _Androspyris pithecus_, n. sp. (Pl. 95, fig. 20). + +Shell smooth, with two slight transverse constrictions. Galea conical, with +a short conical horn, longer than the nut-shaped cephalis. Thorax with +three nearly vertical and parallel feet of equal length. Pores in the galea +and thorax very small and numerous, circular, in the cephalis much larger, +irregular, roundish. + +_Dimensions._--Length of the shell (including horns and feet) 0.25, breadth +0.06 to 0.08. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +4. _Androspyris aptenodytes_, n. sp. + +Shell smooth, with two slight transverse constrictions and irregular, +roundish pores. Galea hemispherical, with a short conical horn, about as +large as the roundish cephalis and half as large as the ovate thorax. The +three feet arise immediately beyond the collar stricture, are equal, +divergent, curved, about as long as the cephalis, and are not terminal (as +in the three preceding species), but lateral appendages of the thorax. + +_Dimensions._--Length of the shell 0.2, breadth 0.05 to 0.07. + +_Habitat._--Antarctic Ocean, Station 157, depth 1950 fathoms. + + + +Genus 480. _Lamprospyris_,[98] Haeckel, 1881, Prodromus, p. 447. + +_Definition._--#Androspyrida# with three free basal feet and a fenestrated +apical horn; lattice-work of the three-jointed shell wholly or partly +spongy. + +The genus _Lamprospyris_ differs from the preceding _Androspyris_, its +ancestral form, mainly in the higher development of the lattice-work of the +large shell. Whilst this in {1094}the latter genus is a simple +lattice-plate, it here becomes more or less spongy, and sometimes forms a +very dense and delicate wickerwork. The apical horn and the three basal +feet are commonly also fenestrated. The two annular strictures, which +separate the cephalis from the conical cupola and the inflated thorax, are +commonly not so distinct as in the preceding genus. Some species belong to +the largest Spyroidea and reach more than half a millimetre in length. + + +1. _Lamprospyris darwinii_, n. sp. (Pl. 89, fig. 13). + +Shell nearly pear-shaped, with two distinct annular strictures, and uneven +papillate surface. The total length is equal to twice the greatest breadth, +and to seven times the length of the ring. Apical horn free, irregularly +branched and fenestrated, as long as the included columella beyond it. The +three diverging feet are strongly curved, S-shaped, and completely included +by loose lattice-work. In the middle of their length they give off a simple +strong lateral branch. The loose arachnoidal lattice-work is rather equally +developed. + +_Dimensions._--Length of the entire shell (including the apophyses) 0.5, +greatest breadth 0.25, ring 0.07 long. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +2. _Lamprospyris lyellii_, n. sp. + +Shell slender, pear-shaped, very similar to the preceding species, but +differing in the following characters--the branched horn is much larger and +twice as long as the columella; the two annular transverse strictures +(separating the three joints) are deeper. The free internal branches of the +three included feet are forked. Lattice-work looser than in the preceding +species. + +_Dimensions._--Length of the entire shell 0.6, breadth 0.2, ring 0.09 long. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +3. _Lamprospyris huxleyi_, n. sp. (Pl. 89, fig. 14). + +Shell ovate, spiny, with two slight annular transverse strictures; their +length equal to one and a half times the breadth, and up to seven times the +length of the ring. Apical horn quite included by the loose lattice-work of +the large conical cupola, which is as long as the cephalis and thorax +together. The three slender feet are also included in the lattice-work and +only one-third as long as the shell, nearly vertical. Lattice-work much +denser than in the two preceding species. + +_Dimensions._--Length of the shell 0.4, breadth 0.26, ring 0.06 long. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + +4. _Lamprospyris hookeri_, n. sp. + +Shell ovato-conical, very similar to the preceding species, but smooth, not +spiny. The apical horn and the three feet are much longer, not included in +the network, but freely prominent, half {1095}as long as the shell and +nearly vertical, parallel. The arachnoidal lattice-work is much denser in +the middle third (cephalis) than in the upper third (cupola) of the lower +third (thorax). + +_Dimensions._--Length of the shell (without appendages) 0.45, breadth 0.3, +ring 0.08 long. + +_Habitat._--Central Pacific, Station 270, depth 2925 fathoms. + + +5. _Lamprospyris spenceri_, n. sp. + +Shell slender, ovate, very similar to the preceding species; differing from +it in the larger cupola, which is as long as the cephalis and thorax +together. The three feet are much shorter and weaker, more divergent. This +differs from all four preceding species in the possession of a large double +apical horn; the two horns are strong, pyramidal, straight, strongly +divergent, and as long as the cupola. + +_Dimensions._--Length of the shell (without the appendages) 0.3, breadth +0.2, ring 0.05 long. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + + +Subfamily 2. PERISPYRIDA, Haeckel, 1881, Prodromus, p. 443. + +_Definition._--#Androspyrida# without free basal feet, with three distinct +joints separated by two parallel transverse strictures. + + + +Genus 481. _Amphispyris_,[99] Haeckel, 1881, Prodromus, p. 444. + +_Definition._--#Androspyrida# without free basal feet, with three distinct +joints, separated by two transverse strictures; lattice-work of the shell +only complete in the frontal ring, with large open holes on the ventral and +dorsal face. + +The genus _Amphispyris_ and the two following genera arising from it, +represent together the peculiar small subfamily of Perispyrida. This may +have originated directly from _Toxarium_ (family Tympanida, Pl. 88, fig. 1; +Pl. 93, figs. 18-20), the large holes between its arches and rings becoming +filled up by lattice-work; in _Amphispyris_ this intercalated network +remains incomplete on the ventral and dorsal faces, whilst in +_Tricolospyris_ it becomes complete, and in _Perispyris_ spongy. + + + +Subgenus 1. _Amphispyrium_, Haeckel. + +_Definition._--On each side of the ring-plane three pairs of large annular +meshes; no middle zygomatic ring is developed between the two tympanic +transverse rings (superior orbital and inferior maxillary ring). + + +{1096}1. _Amphispyris thorax_, n. sp. (Pl. 88, fig. 4). + +Shell thorax-shaped, as long as broad, with a deep sternal incision and two +slight transverse strictures. On each side of the ring-plane three pairs of +large, irregular, annular holes of nearly equal size, the middle holes +nearly half as broad as the shell. No zygomatic bars between the orbital +and maxillary bars. Lateral lattice-girdle narrow, with few small roundish +meshes. + +_Dimensions._--Shell 0.17 long, 0.17 broad, ring 0.06 long. + +_Habitat._--Central Pacific, Station 270, depth 2925 fathoms. + + +2. _Amphispyris quadrigemina_, n. sp. (Pl. 88, fig. 6). + +Shell shaped like the "corpora quadrigemina cerebralia," with two deep +crossed strictures, a coronal transverse stricture and a sagittal sternal +stricture. On each side of the ring plane three pairs of large, irregular, +annular, double holes, the middle holes larger than the upper and lower +holes, and about one-fourth as long as the shell. No zygomatic bars between +the orbital and maxillary bars. Lateral lattice-girdle broad, with numerous +small meshes. + +_Dimensions._--Shell 0.13 long, 0.16 broad, ring 0.07 long. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +3. _Amphispyris reticulata_, Haeckel. + + _Dictyospyris reticulata_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 289, Taf. x. fig. 19. + +Shell thorax-shaped, one and one-fifth times as long as broad, with a deep +sternal incision and two distinct transverse strictures. On each side of +the ring-plane three pairs of large annular holes of nearly equal size, +about one-third as long as the shell. No zygomatic bars between the orbital +and maxillary bars. Lateral girdle narrow, with few large polygonal meshes. + +_Dimensions._--Shell 0.18 long, 0.15 broad. + +_Habitat._--Indian Ocean, Zanzibar, depth 2200 fathoms (Pullen). + + + +Subgenus 2. _Amphispyridium_, Haeckel. + +_Definition._--On each side of the ring-plane four pairs of larger annular +meshes; a middle horizontal zygomatic ring is developed between the two +tympanic transverse rings (superior orbital and inferior maxillary ring). + + +4. _Amphispyris sternalis_, n. sp. (Pl. 88, fig. 2). + +Shell thorax-shaped, one and one-fifth times as long as broad, with deep +sternal incision and two distinct transverse (tympanic) strictures. On each +side of the ring-plane four pairs of large irregular, annular holes; the +fourth (inferior or buccal) pair is the longest. The middle of the sagittal +ring {1097}is crossed by horizontal zygomatic bars (between the ascending +orbital and the descending maxillary bars). Lateral lattice-girdle narrow, +with few large meshes. + +_Dimensions._--Shell 0.24 long, 0.2 broad; ring 0.09 long. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +5. _Amphispyris subquadrata_, n. sp. (Pl. 88, fig. 5). + +Shell compressed, nearly square, spiny, with slight sternal incision and +two distinct transverse strictures. Similar to the preceding species; four +pairs of irregular annular pores of nearly equal size. Zygomatic ring +complete. Lateral lattice-girdle narrow, with few large meshes. + +_Dimensions._--Shell 0.14 long, 0.12 broad; ring 0.06 long. + +_Habitat._--Central Pacific, Station 285, depth 2275 fathoms. + + +6. _Amphispyris costata_, n. sp. (Pl. 88, fig. 3). + +Shell compressed, nearly square, with slight sternal incision and two +obliterated transverse strictures. Similar to the two preceding species; +with four pairs of large annular pores, the two middle of which (the +orbital and nasal holes) are much larger than the superior (frontal) and +inferior (oral) holes. Zygomatic ring incomplete. Lateral lattice-girdle +broad, with very numerous, small, irregular, polygonal pores. + +_Dimensions._--Shell 0.2 long, 0.16 broad; ring 0.07 long. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +7. _Amphispyris toxarium_, n. sp. (Pl. 88, fig. 7). + +Shell inflated, with deep sternal incision and two distinct transverse +strictures. Similar to the preceding species, but with deeper constriction +and looser lattice-work. Four pairs of large, irregular, annular pores, the +central two of which are much larger. Zygomatic ring complete. Lateral +girdle broad, with irregular pores of very different size. + +_Dimensions._--Shell 0.2 long, 0.14 broad; ring 0.09 long. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + + +Genus 482. _Tricolospyris_,[100] Haeckel, 1881, Prodromus, p. 443. + +_Definition._--#Androspyrida# without free basal feet, with three distinct +joints, separated by two transverse strictures; lattice-work of the shell +complete, simple. + +The genus _Tricolospyris_ has arisen from the preceding _Amphispyris_, its +ancestral form, by development of lattice-work which completely closes the +large open holes remaining on the ventral and dorsal faces of the latter. + + +{1098}1. _Tricolospyris kantiana_, n. sp. (Pl. 88, fig. 10). + +Shell smooth, one and a half times as long as broad, with two deep +transverse strictures. Pores of the cephalis large, roundish, of nearly +equal size. Cupola and thorax hemispherical, of about the same size and +form, with numerous and small, double-contoured, roundish pores. + +_Dimensions._--Shell 0.12 long, 0.08 broad; ring 0.04 long. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +2. _Tricolospyris leibnitziana_, n. sp. (Pl. 88, fig. 9). + +Shell spiny, twice as long as broad, with two deep transverse strictures. +Pores of the cephalis large, roundish, polygonally framed, of very +different size; two middle transverse rows of smaller pores enclosed +between a superior and an inferior row of very large pores. Cupola and +thorax hemispherical, about equal, with much smaller and very numerous +roundish pores. + +_Dimensions._--Shell 0.15 long, 0.07 broad; ring 0.06 long. + +_Habitat._--Western Tropical Pacific, Station 224, depth 1850 fathoms. + + +3. _Tricolospyris baconiana_, n. sp. (Pl. 88, fig. 8). + +Shell rough, twice as long as broad, with two sharp strictures. Pores of +the cephalis large, very irregular, partly lobated. Cupola hemispherical, +smaller than the campanulate thorax, both with smaller irregular pores. + +_Dimensions._--Shell 0.15 long, 0.08 broad; ring 0.06 long. + +_Habitat._--Western Tropical Pacific, Station 215, depth 2500 fathoms. + + +4. _Tricolospyris newtoniana_, n. sp. (Pl. 88, fig. 11). + +Shell spiny, slender, three times as long as broad, with two distinct +strictures. Pores of the cephalis very large, irregular. Cupola +hemispherical, only one-third as long as the slender inversely conical +abdomen, both with irregular, much smaller pores. + +_Dimensions._--Shell 0.22 long, 0.08 broad; ring 0.05 long. + +_Habitat._--Western Tropical Pacific, Station 206, depth 2100 fathoms. + + + +Genus 483. _Perispyris_,[101] Haeckel, 1881, Prodromus, p. 444. + +_Definition._--#Androspyrida# without free basal feet, with three distinct +joints, separated by two transverse strictures; lattice-work of the shell +double or spongy. + +The genus _Perispyris_ differs from the preceding _Tricolospyris_, its +ancestral form, in the development of a secondary outer shell, which +encloses the inner primary one either like an enveloping cortical shell or +like a spongy veil. This is produced by the concrescence of meeting +branches, which arise from spines of the inner shell. + + +{1099}1. _Perispyris bicincta_, n. sp. (Pl. 88, fig. 13). + +Shell smooth, with two deep transverse annular strictures and a deep +sagittal incision at the sternal base; one and a half times as long as +broad. Cephalis nut-shaped, with large irregular roundish pores and very +broad bars. Everywhere from its surface there arise numerous slender +arborescent radial beams; by the anastomoses of their ramified branches +there arise the flat cap-shaped cupola and the larger bilobed thorax; and +also the external enveloping shell with loose delicate network. + +_Dimensions._--Inner shell 0.17 long, 0.1 broad; outer shell 0.23 long, +0.17 broad; ring 0.06 long. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +2. _Perispyris spongiosa_, n. sp. + +Shell rough, with two distinct transverse strictures and a deep sternal +incision, similar to the preceding; the radial beams arising from the inner +shell, and forming by anastomosing branches the outer shell, are thinner +and more numerous, and the framework of the latter on the surface is very +dense and spongy, therefore the shell is dark and not transparent. + +_Dimensions._--Inner shell 0.18 long, 0.12 broad; outer shell 0.24 long, +0.18 broad; ring 0.08 long. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +3. _Perispyris lentellipsis_, n. sp. (Pl. 88, fig. 12). + +Shell smooth, lentelliptical, with three different isopolar axes, +perpendicular one to another. Transverse and sagittal strictures are +wanting; but the large enclosed ring and the two pairs of large adjacent +annular meshes indicate clearly the position and size of the hidden +cephalis. The two other joints (the cupola on the upper and the thorax on +the lower pole of the cephalis) are nearly equal, cap-shaped or +hemispherical. The outer lentelliptical shell is little larger than the +inner, connected with it by numerous thin bristle-shaped radial beams, and +exhibits a delicate arachnoidal lattice-work. + +_Dimensions._--Inner shell 0.15 long, 0.1 broad; outer shell 0.18 long, +0.13 broad; ring 0.08 long. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + + +Subfamily 3. NEPHROSPYRIDA (vel PARADICTYIDA, Haeckel, 1881). + +_Definition._--#Androspyrida# without free basal feet and external +constrictions. Shell either spherical or discoidal. + + + +Genus 484. _Sphaerospyris_,[102] n. gen. + +_Definition._--#Androspyrida# with a spherical or subspherical shell, +without basal incision and transverse constriction; without free basal +feet. + +{1100}The genus _Sphaerospyris_ differs from all other #Spyroidea# in the +regular spherical or spheroidal form of the lattice-shell. It may therefore +be easily confounded with some species of the #Sphaeroidea#; but the +internal sagittal ring, placed in the median plane of the fenestrated +sphere and connected with it by radial beams, leaves no doubt that it is +derived from a true Spyroid, either _Dictyospyris_ or _Amphispyris_, or +another genus. Sometimes also four larger collar pores are visible. + + +1. _Sphaerospyris sphaera_, Haeckel. + + _Dictyospyris sphaera_, Buetschli, 1882, Zeitschr. f. wiss. Zool. vol. + xxxvi. pp. 511, 539, Taf. xxxii. fig. 15, _a_, _b._ + +Shell smooth, nearly spherical, slightly flattened at the base, with small +regular circular pores. In the centre of the basal plate a regular +rectangular cross with four equal collar pores. + +_Dimensions._--Diameter of the shell 0.11, of the enclosed ring 0.06. + +_Habitat._--Fossil in Barbados. + + +2. _Sphaerospyris quadriforis_, n. sp. + +Shell rough, nearly spherical, slightly flattened at the base, with small +regular circular pores. In the centre of the basal plate a bilateral +symmetrical cross with four ovate collar pores; two cardinal pores twice as +large as the two jugular pores and six to eight times as broad as the other +shell-pores. + +_Dimensions._--Diameter of the shell 0.26, of the enclosed ring 0.09. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +3. _Sphaerospyris globosa_, n. sp. (Pl. 83, fig. 4). + +Shell smooth, perfectly spherical, with small subregular circular pores. In +the centre of the basal plate no larger collar pores. (The original collar +pores are here of the same size as the other pores, and cannot therefore be +distinguished.) + +_Dimensions._--Diameter of the shell 0.13, of the enclosed ring 0.06. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + + +Genus 485. _Nephrospyris_,[103] Haeckel, 1881, Prodromus, p. 444. + +_Definition._--#Androspyrida# with a discoidal, kidney-shaped, or +subcircular shell, with a basal incision; without transverse constriction +and free basal feet. + +The genus _Nephrospyris_ is one of the most peculiar and most modified of +the #Spyroidea#, of extraordinary size, in this respect surpassing all +other genera of this {1101}suborder, and differing from them in its flat +discoidal form. The diameter of the compressed shell often reaches one half +millimetre or more; its perimeter is elliptical or nearly circular, smooth, +constantly with a characteristic deep sternal incision or a basal sinus on +the basal pole of the main axis. The central sagittal ring is comparatively +small. The margin is often inflated like a delicate reticular girdle, and +contains a large number of peculiar spherical or roundish nucleated cells +(Pl. 90, figs. 6-10). According to the observations of Dr. John Murray, +made on living _Nephrospyris_, they are Vorticellina, perhaps constant +Symbiontes. + + + +Subgenus 1. _Nephrodictyum_, Haeckel, 1881, Prodromus, p. 444. + +_Definition._--Network of the shell simple, with bars of nearly equal +breadth. + + +1. _Nephrospyris renilla_, n. sp. (Pl. 90, figs. 9, 10). + +Shell kidney-shaped, one and a half times as broad as long, and three times +as long as the deep kidney-shaped sternal incision. Ring with six pairs of +branched apophyses, the bars of the apical pair vertical, of the basal pair +divergent. The corresponding bars of the two middle pairs (on the frontal +and the occipital face) form together on each side a large pentagonal or +hexagonal naso-orbital area, which is surrounded by four or five large +polygonal meshes; the other meshes become smaller towards the inflated +margin. All meshes simple, without arachnoidal framework. + +_Dimensions._--Shell 0.3 to 0.4 long, 0.4 to 0.5 broad; ring 0.08 to 0.1 +long. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +2. _Nephrospyris nephridium_, n. sp. + +Shell kidney-shaped, one and two-third times as broad as long, very similar +to the preceding species (or only a variety of it?). Ring with seven pairs +of branched apophyses. The large naso-orbital area is on the dorsal or +occipital side simple, on the ventral or facial side divided by an +equatorial pair of transverse horizontal branches into two superior +orbital, and two inferior nasal holes. Sternal incision ovate. All meshes +simple. + +_Dimensions._--Shell 0.25 to 0.35 long, 0.4 to 0.5 broad; ring .007 to 0.08 +long. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + +3. _Nephrospyris phaseolus_, n. sp. + +Shell kidney-shaped, twice as broad as long, very similar to the two +preceding species (or only a variety of them?). Ring with eight pairs of +branched apophyses. The large naso-orbital area (between the mitral and +collar ring) is on the dorsal and on the ventral side divided by two +equatorial pairs of horizontal branches into two superior (orbital and +occipital), and two inferior (nasal and suboccipital) holes. Sternal +incision cordate. All meshes simple. + +_Dimensions._--Shell 0.25 long, 0.5 broad; ring 0.06 to 0.07 long. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +{1102}4. _Nephrospyris cordata_, n. sp. + +Shell heart-shaped, about as long as broad. Ring with six pairs of branched +apophyses (as in _Nephrospyris renilla_, Pl. 90, fig. 9). No equatorial +transverse branches. Sternal incision cordate, deeper than in all other +species of the genus, nearly half as long as the shell. All meshes of the +network simple. + +_Dimensions._--Shell 0.32 long, 0.36 broad; ring 0.05 to 0.06 long. + +_Habitat._--Central Pacific, Station 263, depth 2650 fathoms. + + + +Subgenus 2. _Paradictyum_, Haeckel, 1881, Prodromus, p. 444. + +_Definition._--Network of the shell double; the larger meshes separated by +strong bars, and filled up by a very delicate secondary arachnoidal +network. + + +5. _Nephrospyris paradictyum_, n. sp. (Pl. 90, figs. 1-8). + + _Paradictyum paradoxum_, Haeckel, 1881, Prodromus et Atlas, _loc. cit._ + +Shell nearly circular, ten times as broad as the inflated marginal girdle, +and three times as long as the sternal incision. Ring with six pairs of +branched apophyses; the bars of the apical pair nearly vertical, of the +basal pair divergent; the corresponding and opposite bars of the two middle +pairs (on the occipital and on the frontal face) form together a large +middle naso-orbital area; above and below this lie six pairs of larger +meshes. All larger meshes of the network are filled up by very delicate +arachnoidal framework. The inflated and delicately reticulated marginal +girdle of this and of the following closely allied species is usually +filled up by nucleated roundish cells (fig. 7), which are Vorticellinae, +according to the observations of Dr. John Murray on living specimens. + +_Dimensions._--Diameter of the shell 0.5 to 0.6, of the marginal girdle +0.05 to 0.07; ring 0.07 to 0.09 long. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +6. _Nephrospyris paradoxa_, n. sp. + +Shell kidney-shaped, one and one-third times as broad as long, six times as +broad as the inflated marginal girdle, and half as long as the sternal +incision. Ring with six pairs of apophyses. Above and below the large +naso-orbital holes lie ten pairs of larger meshes. All the meshes are +filled up by very delicate arachnoidal network. + +_Dimensions._--Length of the shell 0.4 to 0.5, breadth 0.5 to 0.7; ring +0.06 to 0.08 long. + +_Habitat._--Central Pacific, Station 270, depth 2925 fathoms. + + +{1103}---- + + +Suborder II. Botryodea, Haeckel, 1881 (Pl. 96). + + _Polycyrtida_, Haeckel, 1862, Monogr. d. Radiol., p. 341. + _Polycyrtida_, Buetschli, 1882, Zeitschr. f. wiss. Zool., vol. xxxvi. p. + 519. + _Botryodea_ (= _Botrida_ vel _Botryida_), Haeckel, 1881, Prodromus, p. + 439. + +_Definition._--NASSELLARIA with a complete lattice-shell, exhibiting +constantly a lobate and multilocular cephalis, with three to five or more +separated lobes, and two to three or more constrictions. + + +The suborder #Botryodea# differs from the other #Cyrtellaria# in the +multilocular and lobate shape of the cephalis, which is composed of at +least three or four, often five or six, and sometimes even a greater number +of lobes, which are separated by constrictions and partly also by internal +septa. This characteristic shape is found neither in the #Spyroidea# (with +bilocular cephalis) nor in the #Cyrtoidea# (with simple cephalis). The +affinities of the former group to the two latter form a very complicated +problem, which is not yet solved; the morphology of the #Botryodea# is the +most difficult part in the system of NASSELLARIA, and what we can here +give, are incomplete and unsatisfactory beginnings only. + +Up to the year 1860 only a single genus of the #Botryodea# was known, +_Lithobotrys_, one of the oldest genera of "_Polycystina_," and described +by Ehrenberg in 1844 (Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. +74). He gave the following definition:--"Loricae siliceae articuli in +adulto non in seriem, sed in uvae brevis formam, id est in loculos plus +minus discretos nonnullos contiguos dispositi. Proxime ad Lithocampem +accedit." In his first System (1847) _Lithobotrys_ is placed with +_Lithocampe_ among his family Lithochytrina. Afterwards (1860) Ehrenberg +added two new genera, under the names _Botryocampe_ and _Botryocyrtis_ and +figured some species of these incompletely in his last works (1872, 1875). + +In my Monograph I founded for these three genera the separate subfamily of +Polycyrtida, added as a fourth genus _Spyridobotrys_, and gave to the group +the following definition (1862, loc. cit., p. 341):--"Lattice-shell divided +by two or more annular strictures, partly longitudinally, partly +transversely, into three or more unequal chambers, which are placed in +different planes and have a different relation to the poles of the +shell-axis." + +The new and remarkable forms of #Botryodea#, which I subsequently found in +the Challenger collection, demonstrated that the #Botryodea# differ from +the other #Cyrtellaria# (the #Cyrtoidea# as well as the #Spyroidea#) in a +far higher degree than I formerly had supposed. A synopsis of the figures +in Pl. 96 will give sufficient evidence of this view. Therefore in my +Prodromus (1881, p. 439) {1104}I completely separated the #Botryodea# (or +Botrida) from the other suborders of #Cyrtellaria# (Spyrida and Cyrtida). + +Buetschli gave, in 1882, in his paper on the Cyrtida (_loc. cit._) a very +accurate description of _Lithobotrys geminata_, and pointed out its close +affinity to _Lithocorythium_ and _Lithomelissa_, and the importance of an +oblique septum separating the cephalis into a smaller anterior and a larger +posterior lobe. His views on the #Botryodea# (as a subordinate group of the +#Cyrtoidea#) are however incomplete, since the peculiar forms, described in +the following pages, were unknown to him. + +According to the wide morphological divergence of the different +#Botryodea#, and the numerous peculiar forms developed from it, we here +divide the whole group into three families and ten genera, with fifty-five +species. These form, however, only a small part of the large and varied +mass of closely related forms which are found in the rich collections of +the Challenger. The great difficulty of researches on their intimate +structure, and the great amount of time required for it, prevented me from +giving a more complete and exact description than the one here given. The +observation of the small shells from all the different sides is a difficult +task, requiring years of work, and its satisfactory explanation would be +possible only by means of numerous figures. + +The three families of #Botryodea#, here described, correspond to the three +first groups of #Cyrtoidea#. The first family, Cannobotryida, corresponds +to the Monocyrtida clausa and to the Zygospyrida; their shell consists of a +cephalis only, without subsequent joints. The second family, Lithobotryida, +corresponds to the Dicyrtida and Phormospyrida; their shell is composed of +a cephalis and a thorax, both joints being separated by a transverse +cortinar septum and a collar stricture. The third family, Pylobotryida, has +a three-jointed shell, like the Tricyrtida, with cephalis, thorax and +abdomen. + +The cephalis is the most characteristic part of the shell of the +#Botryodea# and its lobulate and multilocular shape separates them from the +#Spyroidea# and #Cyrtoidea#. It represents the whole shell in the +Cannobotryida, and in the young state of the two other families, which +afterwards develop a thorax (Lithobotryida) and an abdomen (Pylobotryida). +The typical lobulation of the cephalis is probably originally caused by +internal septa; and these may be originated by branches of the internal +columella, which corresponds either to the central ascending columella of +the #Plectoidea# or to the excentric ascending dorsal rod of the sagittal +ring of the #Stephoidea#. But afterwards, when the original septa disappear +and are lost by reduction, only the external constrictions remain to +indicate the limits of the single lobes. + +Among the internal septa and the corresponding external constrictions which +effect the lobulation of the cephalis, may be distinguished primary or +constant septa and secondary or inconstant septa. As primary septa we +regard firstly an oblique frontal {1105}septum and secondly a vertical +sagittal septum. The frontal septum (described accurately by Buetschli) has +usually two or three pairs of pores and ascends obliquely from the base to +the anterior face of the cephalis, where it is inserted in the orbital +region; it divides the cephalis into a smaller anterior or facial lobe and +a larger posterior or occipital lobe. The latter is commonly higher and +more developed than the former and partly covers its upper face, like the +crest of a helmet. The facial lobe is again bisected by an incomplete +sagittal septum and a corresponding partial constriction on the anterior +face. We find, therefore, in this original cephalis of the #Botryodea#, +three primary lobes, an odd larger occipital lobe and two paired smaller +facial lobes. The typical trilobed cephalis may be regarded perhaps as the +common original form of the #Botryodea#. + +The secondary and inconstant constrictions which we find in many +#Botryodea#, and which produce a greater number of lobes in the cephalis, +require further accurate observation. The following cases of lobation may +be considered as the most important:--(1) Cephalis with four lobes, +opposite in two pairs (two larger occipital and two smaller facial lobes, +separated by a complete sagittal and an oblique frontal constriction); (2) +cephalis with four unequal lobes, two of which are odd and sagittal, two +paired and lateral (the odd occipital lobe usually larger and the odd +mandibular lobe smaller than the two paired lateral or buccal lobes); (3) +cephalis with five lobes (a large odd occipital lobe and two pairs of +smaller lobes, anterior nasal, and lateral buccal lobes); (4) cephalis with +five lobes, three of which are odd (a posterior occipital, middle frontal, +and anterior facial lobe), and one pair of lateral lobes; (5) cephalis with +six lobes, opposite in pairs (two larger occipital, two smaller nasal and +two intermediate lateral or buccal lobes); (6) cephalis with six lobes, two +of which are odd and sagittal (a large occipital and a smaller nasal lobe), +four opposite in pairs (two anterior and two posterior buccal lobes); (7) +cephalis with seven lobes, three of which are odd (a large posterior +occipital, a middle frontal, and an anterior small nasal lobe), four +opposite in two pairs (an anterior buccal and a posterior temporal pair); +(8) cephalis with eight lobes, two of which are odd (a large posterior +occipital and a small anterior frontal lobe) and six opposite in three +lateral pairs; (9) cephalis with nine lobes, three of which are odd (an +occipital, a frontal and a nasal lobe) and six opposite in three lateral +pairs; (10) cephalis with ten lobes, two of which are odd (a large +occipital and a smaller frontal lobe) and the other eight opposite in +pairs; (11) cephalis with numerous lobes (twelve to fifteen or more) which +are symmetrically disposed on each side of the median plane; (12) cephalis +with numerous lobes (twelve to fifteen or more) which are irregularly and +sometimes spirally conglomerated. + +All these different forms of lobation require a far more thorough +examination than I can devote to them, and may furnish examples of regular +laws of development. The irregular forms are rather common, and I have +found some very irregular #Botryodea# {1106}(not here described) in which I +could not determine the topographical regions of the cephalis. The +difficulty in the examination of these complicated forms is increased by +their very small size, which does not reach the usual dimensions of the +other #Cyrtellaria#. In some cases I was able to observe on the base of the +cephalis the same typical cortinar pores (in two or three pairs), which we +also find in the same part of the cephalis in the #Spyroidea# and +#Cyrtoidea#, and which are inherited from the Semantida. + +The thorax of the #Botryodea#, or the second shell-joint, absent in the +Cannobotryida, is usually of very simple form, ovate, truncate, conical or +cylindrical, and consists of a secondary joint, developed from the base of +the cephalis. The thorax is usually small, about the same size as the +cephalis or a little larger, whilst in the #Cyrtoidea# it is commonly much +larger than the latter. Its terminal mouth is closed by a lattice-plate in +the Botryocellida, while it remains open in the Botryopylida and +Pylobotryida. + +The abdomen, or the third shell-joint, developed in the Pylobotryida only, +generally also exhibits a very simple shape, like the thorax, and it is a +tertiary joint developed from the base of the thorax. It exhibits to the +latter the same relation as in the Tricyrtida. The terminal mouth of the +abdomen remains open in the Botryocyrtida; it becomes closed by a +lattice-plate in the Botryocampida. + +The lattice-plate forming the shell of the #Botryodea# is usually very thin +and fragile, with very small circular pores. These are often very numerous, +at other times scarce, and sometimes nearly wanting, so that the shell +appears hyaline. In this group there never occurs that great variety in +form and size of the pores, which numerous #Cyrtoidea# and #Spyroidea# +exhibit. + +The radial apophyses which are found in the majority of #Botryodea# seem to +correspond in position and relation to the typical radial beams of the +other NASSELLARIA, viz., three descending basal feet arising from the base +of the cephalis, and an ascending vertical apical horn arising from the top +of the cephalis. Here also they seem to be inherited from the #Plectoidea# +or #Stephoidea# (_Cortina_, _Cortiniscus_). But whilst these four typical +radial beams in the other NASSELLARIA are usually simple spines or solid +rods, here they usually appear as hollow cylindrical tubes, the thin wall +of which is pierced by the same small pores as the shell. These porous +tubes are either straight or slightly curved, often inflated and ovate at +the base. We find in their number and disposition the same variety as in +the simple radial spines of the other NASSELLARIA. The original number may +here also be seen in the development of four typical beams, an ascending +apical tube on the top of the cephalis, and three descending basal tubes on +its base; the odd posterior tube of the latter corresponds to the caudal +foot, the two paired anterior to the pectoral feet. There is often also a +fourth foot developed opposite to the caudal, and representing a sternal +tube. Sometimes also two superior tubes are developed, a posterior +occipital and an anterior frontal. The different {1107}apophyses may be +lost by reduction. I have never observed #Botryodea# with more than five +apophyses. + +_The Central Capsule_ of the #Botryodea# is not yet sufficiently known, no +living species having been observed. In some preparations from specimens in +the Challenger collections, stained by Dr. John Murray with carmine +immediately after the dredging operation, single #Botryodea# are to be +found in which the central capsule is deeply coloured. In _Botryopera +quinqueloba_ (Pl. 96, fig. 2) it filled up the greater part of the cephalis +and seemed to be divided into some small lobes. In _Lithobotrys +sphaerothorax_ (Pl. 96, fig. 15) it was divided into four lobes, three of +which filled the trilobed cephalis, the fourth large lobe occupying a great +part of the spherical thorax. Details of their structure, unfortunately, +were not recognisable. There can, however, be no doubt that they are the +same as in all other NASSELLARIA. + +_Synopsis of the Families of_ #Botryodea#. + + 1. Shell monothalamous, consisting of the lobate + cephalis only, 1. CANNOBOTRYIDA. + + 2. Shell dithalamous, composed of a lobate cephalis + and a simple thorax, 2. LITHOBOTRYIDA. + + 3. Shell trithalamous, composed of a lobate cephalis, + a thorax and an abdomen, 3. PYLOBOTRYIDA. + + + +Family LVI. #CANNOBOTRYIDA#, Haeckel (_sensu emendato_). + + _Cannobotryida_, Haeckel, 1881, Prodromus, p. 440. + +_Definition._--Botryodea monothalamia, the shell of which represents a +lobate cephalis, without thorax and abdomen. + +The family #Cannobotryida# (retained here with a stricter definition than +originally was given in my Prodromus) comprises those #Botryodea#, in which +the whole shell is represented by the cephalis alone, without thorax and +abdomen. Since the two latter joints, found in the two following families, +are secondary productions, the Cannobotryida must be regarded as the +ancestral forms of all #Botryodea#, in an ontogenetic as well as in a +phylogenetic sense. + +Two species only of this family have been hitherto known, incompletely +described by Ehrenberg as _Lithobotrys triloba_ and _Lithobotrys +quadriloba_. A great number of similar forms are to be found in the +Radiolarian ooze of the Central Pacific, but they are very minute, and +difficult to examine. We can describe here only twelve species of these, +which we arrange in two genera; _Botryopera_ without porous tubes, and +_Cannobotrys_ bearing a variable number of porous cylindrical tubes (one to +five). The number of lobes of the cephalis is also variable in each genus +(one to five or more). If in the future these minute and interesting shells +should be better examined, it would {1108}be advisable to distinguish a +number of genera according to the different number of the porous tubes and +of the lobes of the cephalis. The base of the latter is constantly closed +by a basal lattice-plate, and usually exhibits two or three pairs of +cortinar pores, identical with those of the Semantida. + +The phylogenetic origin of the Cannobotryida may be found either in the +Zygospyrida or in the Monocyrtida; they differ from these two similar +groups in the lobation of the cephalis, which is effected by the +development of internal septa and external constrictions. + +_Synopsis of the Genera of Cannobotryida._ + + Cephalis without porous tubes, 486. _Botryopera_. + + Cephalis with a variable number of porous tubes, 487. _Cannobotrys_. + + + +Genus 486. _Botryopera_,[104] n. gen. + +_Definition._--#Cannobotryida# without tubes on the cephalis. + +The genus _Botryopera_ is the simplest form among the #Botryodea#, the +shell consisting of a lobate cephalis only, without tubes or radial +appendages. It may be derived either from _Dictyospyris_ or from +_Archicapsa_ by development of the horizontal fold in the frontal face of +the shell, and the corresponding internal frontal septum, which separates +the larger occipital lobe from the smaller facial half; the latter may be +divided again into paired frontal lobes, lateral buccal lobes, &c. +_Botryopera_ may be the common ancestral form of many #Botryodea#. + + +1. _Botryopera cyrtoloba_, n. sp. (Pl. 96, fig. 1). + +Cephalis trilobate; the posterior odd occipital lobe helmet-shaped, about +twice as large as the two paired anterior frontal lobes, which are subovate +and covered by the upper half of the former. Pores small and numerous, +subregular, circular; some larger pores at the base. + +_Dimensions._--Length of the shell 0.08, basal breadth 0.06. + +_Habitat._--Central Pacific, Station 265 to 274, depth 2350 to 2925 +fathoms. + + +2. _Botryopera triloba_, Haeckel. + + _Lithobotrys triloba_, Ehrenberg, 1854, Mikrogeol., Taf. xxii. fig. 30. + +Cephalis trilobate; the occipital lobe subcylindrical, one and a half times +as long as the two frontal lobes, which are slender, ovate and not covered +by the former. Pores small and numerous. + +_Dimensions._--Length of the shell 0.05, breadth 0.03. + +_Habitat._--Fossil in Tertiary rocks of the Mediterranean (Sicily, Greece, +&c.) + + +{1109}3. _Botryopera quadriloba_, Haeckel. + + _Lithobotrys quadriloba_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, p. 84. + +Cephalis quadrilobate; the occipital lobe helmet-shaped, one and a half +times as long as the two paired hemispherical buccal lobes, and twice as +large as the anterior frontal lobe. Pores not numerous, rather large, +circular. + +_Dimensions._--Length of the shell 0.06, breadth 0.04. + +_Habitat._--Fossil in Barbados and North America (Virginia). + + +4. _Botryopera quinqueloba_, n. sp. (Pl. 96, fig. 2). + +Cephalis quinquelobate; the occipital lobe helmet-shaped, and twice as long +as the two hemispherical frontal lobes, three times as long as the +subspherical lateral buccal lobes. Pores scarce, small, circular. + +_Dimensions._--Length of the shell 0.07, basal breadth 0.05. + +_Habitat._--North Pacific, Station 253, depth 3125 fathoms. + + +5. _Botryopera multiloba_, n. sp. + +Cephalis multilobate; the posterior odd occipital lobe ovate, and of about +the same size as the anterior frontal half of the shell, which is clustered +and divided into five to seven smaller lobes, an odd subspherical sternal +lobe, and on each side of it two or three pairs of smaller subspherical +lobes. + +_Dimensions._--Length of the shell 0.09, breadth 0.06. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + + +Genus 487. _Cannobotrys_,[105] Haeckel, 1881, Prodromus p. 440. + +_Definition._--#Cannobotryida# with tubes on the cephalis. + +The genus _Cannobotrys_ differs from the preceding _Botryopera_ in the +development of hollow radial tubes, arising from the lobate cephalis in +various numbers. According to their number the genus may be divided into +various subgenera: (1) _Cannobotrantha_ (_monocanna_) with a single apical +tube; (2) _Cannobotrella_ (_dicanna_) with two divergent tubes, an +ascending apical and a descending sternal one; (3) _Cannobotrissa_ +(_tricanna_) with three tubes in the sagittal plane (an upper apical, a +posterior caudal, and an anterior sternal); (4) _Cannobotromma_ +(_tetracanna_) with four radial tubes disposed like the four typical spines +of _Cortina_ (compare p. 950), and _Cannobotrusa_ (_pentacanna_) with five +radial tubes disposed like the five typical spines of _Stephanium_ (p. +952). {1110}Perhaps these five groups may be separated as five genera, +possessing near relations to five very different genera of NASSELLARIA +(_Circospyris_, _Halicapsa_, _Archibursa_, _Cortina_, _Stephanium_, &c.) + + +1. _Cannobotrys monocanna_, n. sp. + +Cephalis trilobate, with a single cylindrical straight apical tube on the +apex of the occipital lobe, which is helmet-shaped, and about one and a +half times as long as the two subspherical frontal lobes. Pores small and +numerous, subregular, circular. + +_Dimensions._--Length of the shell 0.05, breadth 0.03. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + +2. _Cannobotrys dicanna_, n. sp. + +Cephalis quadrilobate, with two divergent tubes, an odd apical tube on the +apex of the posterior occipital lobe, and an odd sternal tube on the +anterior frontal lobe. Between these two odd lobes lie two paired lateral +or buccal lobes, of about the same size. Shell nearly hyaline, with very +few minute pores. + +_Dimensions._--Length of the shell 0.06, breadth 0.04. + +_Habitat._--Indian Ocean; Madagascar (Rabbe), surface. + + +3. _Cannobotrys tricanna_, n. sp. (Pl. 96, fig. 3). + +Cephalis quinquelobate, with three curved cylindrical tubes in the sagittal +plane; an ascending apical tube on the apex of the helmet-shaped occipital +lobe, and two horizontal tubes on the base of the shell (a posterior +caudal, _c_, and an anterior sternal, _z_). The two frontal lobes are +hemispherical, and twice as large as the two lateral buccal lobes. Pores +very small and numerous. + +_Dimensions._--Length of the shell 0.08, basal breadth 0.06. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +4. _Cannobotrys sagittalis_, n. sp. + +Cephalis multilobate, with three straight divergent cylindrical tubes in +the sagittal plane; a vertical apical tube on the apex of the ovate +occipital lobe, and two horizontal tubes on the base, as in the preceding +similar species; it differs from the latter in the greater number of lobes +(seven or nine), the two frontal lobes being divided into two or four +secondary lobules. + +_Dimensions._--Length of the shell 0.1, breadth 0.07. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + +5. _Cannobotrys cortina_, n. sp. (Pl. 96, fig. 4). + +Cephalis quinquelobate, with four cylindrical nearly straight tubes of +equal size; an ascending, nearly vertical, apical tube on the apex of the +occipital lobe, and three divergent descending tubes {1111}on the base of +the shell (an odd posterior caudal tube and two paired anterior pectoral +tubes). The two lateral buccal lobes are twice as large as the two anterior +frontal lobes, and half as large as the posterior odd occipital lobe. The +four tubes in this and the following species correspond probably to the +four spines of _Cortina_ (p. 950). + +_Dimensions._--Length of the shell 0.07, basal breadth 0.06. + +_Habitat._--Central Pacific, Stations 263 to 274, depth 2350 to 2925 +fathoms. + + +6. _Cannobotrys tetracanna_, n. sp. + +Cephalis multilobate, with four cylindrical curved tubes conical at their +wider base, corresponding to those of the preceding species and to the four +spines of _Cortina_. The odd occipital lobe is of about the same size as +the anterior part of the shell, which is cleft into three pairs of roundish +lobes, one pair of anterior larger frontal lobes, and two pairs of smaller +lateral buccal lobes. Pores very few and minute. + +_Dimensions._--Length of the shell 0.11, basal breadth 0.07. + +_Habitat._--North Pacific, Station 253, depth 3125 fathoms. + + +7. _Cannobotrys pentacanna_, n. sp. + +Cephalis quinquelobate, with five cylindrical slender curved tubes, three +of which are placed in the sagittal plane (a superior apical, a posterior +caudal, and an anterior sternal), whilst the other two are paired and +diverge laterally (two pectoral tubes). The five tubes correspond exactly +to the five typical spines of _Stephanium_ (p. 952). The helmet-shaped +occipital lobe of the shell is twice as large as each of the two anterior +frontal lobes, and three times as large as each of the two lateral buccal +lobes. Pores numerous. + +_Dimensions._--Length of the shell 0.07, basal breadth 0.04. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + + +Family LVII. #LITHOBOTRYIDA#, n. fam. + +_Definition._--Botryodea dithalamia, the shell of which is composed of a +lobate cephalis and a simple thorax, without abdomen. + +The family #Lithobotryida# comprises those #Botryodea# in which the shell +is divided by a transverse annular constriction into a lobate cephalis and +a simple thorax. They correspond therefore to the Dicyrtida among the +#Cyrtoidea#, and to the Phormospyrida among the #Spyroidea#. The thorax, or +the second shell-joint, is in all these three families a secondary +production, arising from the base of the cephalis; therefore the +Lithobotryida must be phylogenetically derived from the Cannobotryida. + +Several species of _Lithobotrys_ were first described by Ehrenberg as +_Lithobotrys_ and _Lithocorythium_. These two genera are, however, +identical, as has been {1112}demonstrated by Buetschli (1882, _loc. cit._, +p. 519). Some other species united by Ehrenberg with _Lithobotrys_ belong +to other genera. The number of Lithobotryida found in the "Radiolarian +ooze" of the Challenger collection, is far greater than that of the +Cannobotryida and Pylobotryida. But only a small part of them could be +thoroughly examined and described here, so that their number may be greatly +augmented by further accurate researches. We here arrange those forms in +four genera, representing two different subfamilies. The terminal mouth of +the thorax remains open in the Botryopylida, whilst it becomes closed by a +lattice-plate in the Botryocellida. In each group there are shells with and +without porous tubes. The number of these tubes, and also the number of +lobes of the cephalis, is very variable, and may in future serve for the +distinction of more genera. + +_Synopsis of the Genera of Lithobotryida._ + + {Cephalis without porous + I. Subfamily Botryopylida. { tubes, 488. _Botryopyle_. + { + Mouth of the thorax open. {Cephalis with a + { variable number of + { porous tubes, 489. _Acrobotrys_. + + {Cephalis without + II. Subfamily Botryocellida. { porous tubes, 490. _Botryocella_. + { + Mouth of the thorax closed {Cephalis with a + by a lattice-plate. { variable number of + { porous tubes, 491. _Lithobotrys_. + + + +Genus 488. _Botryopyle_, Haeckel, 1881, Prodromus, p. 440. + +_Definition._--#Lithobotryida# without tubes on the cephalis, and with the +mouth of the thorax open. + +The genus _Botryopyle_ comprises the simplest forms of Lithobotryida, the +lobate cephalis bearing no tubes and the basal mouth of the thorax +remaining open. It may be derived either from _Dictyocephalus_ or from +_Desmospyris_, by development of lobes on the cephalis and of an internal +frontal septum, separating the larger occipital lobe from the smaller +frontal half of the shell. The latter may be divided again into anterior +frontal lobes, lateral buccal lobes, &c. + + +1. _Botryopyle sethocorys_, n. sp. (Pl. 96, fig. 7). + +Cephalis trilobate, separated by a deep collar constriction from the +hemispherical thorax, which is twice as broad. Occipital lobe +helmet-shaped, little longer than the two hemispherical frontal lobes. +Surface spiny. Pores irregular, roundish, of very different size. + +_Dimensions._--Length of the shell 0.1, breadth 0.07. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +{1113}2. _Botryopyle cribrosa_, Haeckel. + + _Lithobotrys cribrosa_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 76, Taf. iii. fig. 20. + + ? _Lithobotrys biceps_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 295, Taf. ix. fig. 23. + +Cephalis trilobate, separated by a slight collar constriction from the +ovate thorax, which is somewhat smaller. Occipital lobe very large, +helmet-shaped, longer than the thorax and twice as long as the two +subspherical frontal lobes. Pores regular, circular, scarce. + +_Dimensions._--Length of the shell 0.11, breadth 0.05. + +_Habitat._--Fossil in Barbados. + + +3. _Botryopyle cephalodes_, Haeckel. + + _Lithocorythium cephalodes_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 78, Taf. iv. fig. 6. + +Cephalis quinquelobate, separated by a slight collar constriction from the +larger conical thorax, which is gradually dilated towards the wide mouth. +Occipital lobe helmet-shaped, little longer than the frontal half of the +cephalis, which is divided into two pairs of lateral chambers, +corresponding to the four crossed pores of the sagittal septum, figured by +Ehrenberg. The figure of the latter is inverse, seen from the frontal face, +a part of the frontal wall having been broken off. + +_Dimensions._--Length of the shell 0.08, breadth 0.05. + +_Habitat._--Fossil in Barbados. + + +4. _Botryopyle dictyocephalus_, n. sp. (Pl. 96, fig. 6). + +Cephalis multilobate, separated by an oblique constriction from the +subcylindrical thorax, which is somewhat larger and slightly curved. +Occipital lobe conical, of the same length as the posterior part of the +triangular frontal half of the shell, which is divided into five to seven +lobes, two or three odd lobes in the median part, and one or two pairs of +lateral lobes; very variable in size and form of the lobes. Mouth of the +thorax wide, truncate. + +_Dimensions._--Length of the shell 0.12, breadth 0.07. + +_Habitat._--Central Pacific, Station 271 to 274, depth 2350 to 2750 +fathoms. + + +5. _Botryopyle inclusa_, n. sp. (Pl. 96, fig. 5). + +Cephalis multilobate, campanulate, separated by a sharp constriction from +the inflated thorax, which is nearly twice as long and broad. Both joints +of the shell are irregularly lobate, with numerous vaulted lobes of +different sizes, and partly internal septa. Pores small and numerous. + +_Dimensions._--Length of the shell 0.1, breadth 0.06. + +_Habitat._--Mediterranean (Candia), Spratt, depth 1620 fathoms. + + + +{1114}Genus 489. _Acrobotrys_, Haeckel,[106] 1881, Prodromus, p. 440. + +_Definition._--#Lithobotryida# with tubes on the cephalis, and with the +mouth of the thorax open. + +The genus _Acrobotrys_ differs from the preceding _Botryopyle_ in the +development of radial tubes, and from its probable ancestral form, +_Cannobotrys_, in the development of a thorax, the basal mouth of which +remains open. According to the varying number of the tubes we may +distinguish the following five subgenera (corresponding to those of +_Cannobotrys_), viz., (1) _Acrobotrantha_ (_monosolenia_) with a single +(apical) tube; (2) _Acrobotrella_ (_disolenia_) with two divergent tubes +(an apical and a sternal); (3) _Acrobotrissa_ (_trisolenia_) with three +sagittal tubes (an apical, a caudal, and a sternal); (4) _Acrobotromma_ +(_tetrasolenia_) with four tubes, like the four typical spines of +_Cortina_; and (5) _Acrobotrusa_ (_pentasolenia_) with five feet, +corresponding to the five typical spines of _Stephanium_. + + +1. _Acrobotrys monosolenia_, n. sp. + +Cephalis trilobate, with a single straight apical tube, which ascends +vertically from the apex of the occipital lobe, and is pointed at the +distal end, with an anterior oblique aperture. Two frontal lobes paired, +ovate, half as long as the helmet-shaped occipital lobe. Thorax ovate, +twice as long as the cephalis. Pores very scarce. + +_Dimensions._--Length of the shell 0.08, breadth 0.06. + +_Habitat._--Mediterranean (Corfu), surface. + + +2. _Acrobotrys disolenia_, n. sp. (Pl. 96, fig. 10). + +Cephalis trilobate, with three odd ovate lobes of nearly equal size in the +sagittal plane and two divergent straight slender cylindrical tubes, a +vertical apical tube on the occipital lobe, and a horizontal nasal tube on +the frontal lobe; the middle lobe between them is somewhat smaller. Thorax +ovate, about twice as large as the cephalis, with constricted mouth. Pores +small and numerous. + +_Dimensions._--Length of the shell 0.1, breadth 0.06. + +_Habitat._--Central Pacific, Station 265 to 274, depth 2350 to 2925 +fathoms. + + +3. _Acrobotrys aquaria_, n. sp. + +Cephalis quinquelobate, with two divergent long cylindrical curved tubes. +Occipital lobe helmet-shaped, with an ascending apical tube; nasal lobe +conical, with a descending sternal tube; {1115}between them a smaller odd +middle lobe, and on each side of the latter an ovate frontal lobe. Thorax +inflate, twice as long and broad as the cephalis. Pores small, scarce. + +_Dimensions._--Length of the shell 0.09, breadth 0.07. + +_Habitat._--South Pacific, Station 285, depth 2375 fathoms. + + +4. _Acrobotrys acuminata_, n. sp. (Pl. 96, fig. 9). + +Cephalis sexlobate, with two divergent tubes. Occipital and frontal lobes +ovate, odd; between them a cupola-shaped apical lobe, bearing an ascending +pointed apical tube. On each side at the base a small buccal lobe, and +between the paired buccal lobes an anterior nasal lobe with a descending +curved sternal tube. Thorax smaller than the cephalis. Pores numerous and +small. + +_Dimensions._--Length of the shell 0.11, breadth 0.09. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +5. _Acrobotrys auriculata_, n. sp. (Pl. 96, fig. 11). + +Cephalis quadrilobate, with three pointed and auriculate tubes, two +ascending apical (an anterior and a posterior) in the helmet-shaped +occipital lobe, and a descending sternal tube on the base of the frontal +lobe; between the lobes two lateral paired buccal lobes. Thorax +campanulate, twice as broad as the cephalis. Pores rather large and +numerous. + +_Dimensions._--Length of the shell 0.1, breadth 0.08. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +6. _Acrobotrys trisolenia_, n. sp. (Pl. 96, fig. 8). + +Cephalis quadrilobate, with four odd lobes and three divergent curved +tubes, an ascending apical tube in the conical occipital lobe, and two +descending tubes on the anterior and posterior basal lobes; between these +three lobes a small central lobe. Thorax ovate, about as large as the +cephalis. Pores small and numerous. + +_Dimensions._--Length of the shell 0.11, breadth 0.05. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +7. _Acrobotrys tetrasolenia_, n. sp. + +Cephalis trilobate, with four slender cylindrical tubes. Occipital lobe +helmet-shaped, with an apical tube on the apex and a caudal tube on the +base. Two frontal lobes ovate, prolonged into two paired pectoral tubes. +The four tubes correspond in position to the four spines of Cortina. Thorax +inflate, ovate, larger than the cephalis. Pores very scarce, rather large, +irregular. + +_Dimensions._--Length of the shell 0.08, breadth 0.05. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +8. _Acrobotrys pentasolenia_, n. sp. + +Cephalis quinquelobate, with five short conical tubes; three divergent odd +tubes arise from three odd lobes; an apical from the occipital lobe, a +posterior caudal from the suboccipital lobe, and an {1116}anterior sternal +from the nasal lobe. Two paired lateral tubes arise from the base of two +ovate frontal lobes. The five tubes correspond in disposition to the five +spines of Stephanium. Thorax truncate. Pores small. + +_Dimensions._--Length of the shell 0.12, breadth 0.09. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + + +Genus 490. _Botryocella_,[107] Haeckel, 1881, Prodromus, p. 440. + +_Definition._--#Lithobotryida# without tubes on the cephalis, and with the +mouth of the thorax closed. + +The genus _Botryocella_ differs from the closely allied _Botryopyle_ in +having the mouth of the thorax closed, and may be derived from it by +development of a lattice-plate, effecting this closure. It bears therefore +the same relation to the latter that _Dicolocapsa_ has to _Dictyocephalus_. + + +1. _Botryocella nucula_, Haeckel. + + _Lithobotrys nucula_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 76, Taf. iii. fig. 16. + + _Lithobotrys adspersa_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 76, Taf. iii. fig. 15. + +Cephalis trilobate; occipital lobe helmet-shaped, nearly twice as long as +the two ovate frontal lobes. Thorax about as long as the cephalis. Pores +very small and scarce. + +_Dimensions._--Length of the shell 0.06, breadth 0.03. + +_Habitat._--Fossil in Barbados. + + +2. _Botryocella borealis_, Haeckel. + + _Lithobotrys borealis_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 294, Taf. ii. fig. 3. + +Cephalis trilobate; occipital lobe ovate, little longer than the two ovate +frontal lobes. Thorax about twice as long as the cephalis. Pores very +numerous and small. + +_Dimensions._--Length of the shell 0.08, breadth 0.04. + +_Habitat._--North Atlantic, Greenland, depth 1000 to 2000 fathoms. + + +3. _Botryocella tricellaris_, n. sp. + +Cephalis trilobate, with three odd sagittal lobes; the middle or central +lobe larger than the anterior frontal and smaller than the posterior +occipital lobe. Thorax nearly spherical, about as long as the cephalis. +Pores small and scarce. + +_Dimensions._--Length of the shell 0.08, breadth 0.06. + +_Habitat._--North Atlantic, Station 353, depth 2965 fathoms. + + +{1117}4. _Botryocella quadricellaris_, n. sp. (Pl. 96, fig. 13). + +Cephalis quadrilobate; the helmet-shaped occipital lobe twice as long as +the two paired subspherical buccal lobes, and three times as long as the +odd spherical frontal lobe. Thorax nearly spherical, about as long as the +cephalis. + +_Dimensions._--Length of the shell 0.1, breadth 0.05. + +_Habitat._--Central Pacific, Station 272, depth 4475 fathoms. + + +5. _Botryocella quadrigemina_, n. sp. (Pl. 96, fig. 14). + +Cephalis quadrilobate, with two pairs of lateral ovate lobes and complete +sagittal constriction; the two occipital lobes nearly twice as large as the +two frontal lobes. Thorax ovate, separated from the cephalis by a collar +septum with four cortinar pores (fig. 14). + +_Dimensions._--Length of the shell 0.09, breadth 0.06. + +_Habitat._--Indian Ocean, Sunda Strait (Rabbe), surface. + + +6. _Botryocella multicellaris_, n. sp. (Pl. 96, fig. 12). + +Cephalis multilobate; occipital lobe helmet-shaped, very large, about twice +as long and broad as the frontal half of the shell, which is divided into +six to eight small roundish clustered lobes. Thorax subspherical, of about +the same size as the cephalis. + +_Dimensions._--Length of the shell 0.1, breadth 0.05. + +_Habitat._--South Pacific Station 297, depth 1775 fathoms. + + + +Genus 491. _Lithobotrys_,[108] Ehrenberg, 1844, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 74. + +_Definition._--#Lithobotryida# with tubes on the cephalis, and with the +mouth of the thorax closed. + +The genus _Lithobotrys_, the oldest and first known of the #Botryodea#, was +founded by Ehrenberg in 1844, and was one of his five oldest genera of +Polycystina. It represented by itself the suborder #Botryodea# until the +year 1860. The numerous species described by Ehrenberg belong to very +different genera of #Botryodea#, and partly also of #Spyroidea#. Following +Buetschli (1882) we retain here the name _Lithobotrys_ for those species, +the type of which is _Lithobotrys geminata_. The genus _Lithocorythium_ of +Ehrenberg is for the greater part identical with it. When in the preceding +genus _Acrobotrys_ the mouth of the thorax becomes closed by lattice work, +_Lithobotrys_ arises. In the latter as well as in the former the number of +tubes on the cephalis is different, and may characterise different +subgenera. + + +{1118}1. _Lithobotrys geminata_, Ehrenberg. + + _Lithobotrys geminata_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 76, Taf. iii. fig. 19. + + _Lithobotrys geminata_, Buetschli, 1882, Zeitschr. f. wiss. Zool., vol. + xxxvi, p. 519, Taf. xxxiii. fig. 27, a to c. + + ? _Lithocorythium platylophus_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 78, Taf. iv. fig. 5. + +Cephalis trilobate, with a single apical tube in the apex of the +helmet-shaped occipital lobe, which is one and a half times as long as the +two subspherical frontal lobes. Thorax ovate, one and a half times as long +as the cephalis, with few small pores in six to eight transverse rows. + +_Dimensions._--Length of the shell 0.1, breadth 0.05. + +_Habitat._--Fossil in Barbados. + + +2. _Lithobotrys lithocorythium_, Haeckel. + + _Lithocorythium oxylophus_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 78, Taf. iv. figs. 3, 4. + + ? _Lithopera oxystauros_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 78, Taf. iii. fig. 6. + +Cephalis trilobate, with a single apical horn or a pointed tube in the apex +of the helmet-shaped occipital lobe, which is a little longer than the two +ovate frontal lobes. Thorax ovate, about as long as the cephalis, with very +numerous and small pores. + +_Dimensions._--Length of the shell 0.08, breadth 0.04. + +_Habitat._--Fossil in Barbados. + + +3. _Lithobotrys nasuta_, Ehrenberg. + + _Lithobotrys nasuta_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 76, Taf. iii. fig. 21. + +Cephalis quadrilobate, with a single descending sternal or nasal tube on +the base of the anterior or frontal lobe, which is half as long as the +helmet-shaped occipital lobe and twice as large as the two lateral buccal +lobes. Thorax ovate, twice as long as the cephalis. Pores rather large, +circular. + +_Dimensions._--Length of the shell 0.11, broad 0.05. + +_Habitat._--Fossil in Barbados. + + +4. _Lithobotrys ornata_, Ehrenberg. + + _Lithobotrys ornata_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 76, Taf. iii. fig. 18. + +Cephalis quinquelobate, with two divergent ascending tubes, a posterior +occipital and an anterior sternal or nasal tube. Occipital lobe +campanulate, twice as large as the two frontal, and four times as large as +the two buccal lobes. Thorax ovate, twice as long as the cephalis. Pores +scarce and small. The specimen figured by Ehrenberg is very incomplete. + +_Dimensions._--Length of the shell 0.09, breadth 0.05. + +_Habitat._--Fossil in Barbados. + + +{1119}5. _Lithobotrys sphaerothorax_, n. sp. (Pl. 96, fig. 15). + +Cephalis trilobate, with two divergent cylindrical tubes, an ascending +apical tube in the apex of the ovate occipital lobe, and a descending +sternal or nasal tube in the campanulate frontal lobe; between the two +lobes a smaller central lobe. Thorax spherical, twice as long as the +latter. Pores very small, numerous. + +_Dimensions._--Length of the shell 0.08, breadth 0.06. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4575 fathoms. + + +6. _Lithobotrys mascula_, n. sp. (Pl. 96, fig. 16). + +Cephalis sexlobate, with two divergent cylindrical tubes, an ascending +apical tube in the apex of the helmet-shaped occipital lobe and a +descending sternal tube on the base, between the two kidney-shaped frontal +lobes. The latter are half as large as the odd occipital lobe and of about +the same size as the two inflated lateral buccal lobes, which are separated +by a small odd nasal lobe. + +_Dimensions._--Length of the shell 0.13, breadth 0.08. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + +7. _Lithobotrys orchidea_, n. sp. (Pl. 96, fig. 17). + +Cephalis sexlobate, similar to the preceding species, but with five +divergent and curved cylindrical tubes, which correspond to the five spines +of _Stephanium_; an apical tube on the apex of the occipital lobe, a caudal +tube on its base, a sternal tube between the two frontal lobes, and two +paired pectoral tubes between the latter and the lateral buccal lobes. +Pores small and scarce. + +_Dimensions._--Length of the shell 0.12, breadth 0.06. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +Family LVIII. #PYLOBOTRYIDA#, Haeckel (_sensu emendato_). + + _Pylobotryida_, Haeckel, 1881, Prodromus, p. 440. + +_Definition._--Botryodea trithalamia, the shell of which is composed of a +lobate cephalis, a thorax, and an abdomen. + +The family #Pylobotryida# comprises those #Botryodea# in which the shell +exhibits two parallel transverse annular constrictions, and is divided by +these into three successive joints, corresponding to the cephalis, the +thorax, and the abdomen of the Tricyrtida. As in the latter, the abdomen is +here also a later production, arising from the terminal mouth of the +thorax; therefore the Pylobotryida must be derived phylogenetically from +the Lithobotryida. + +Two genera of Pylobotryida were incompletely described in 1860 by +Ehrenberg, _Botryocyrtis_ and _Botryocampe_. We retain them here, with a +stricter definition, however. Two other genera were added in my +Prodromus--_Pylobotrys_ and _Phormobotrys_. {1120}The small number of +species here enumerated may be easily increased, since numerous forms, +belonging probably to this family, are not sufficiently known. Their study +is, however, very difficult and requires accurate examination of the tiny +shells from different sides. + +The four genera of Pylobotryida, here described, represent two different +subfamilies. The terminal mouth of the abdomen remains open in the +Botryocyrtida, whilst it becomes closed by a lattice-plate in the +Botryocampida. There are in both groups shells with and without porous +tubes; the number of these tubes, and also the number and disposition of +the lobes in the cephalis, exhibits remarkable differences in the different +species of those genera, and may in future serve for their division into a +greater number of genera. + +_Synopsis of the Genera of Pylobotryida._ + + { Cephalis without + I. Subfamily Botryocyrtida. { porous tubes, 492. _Botryocyrtis_. + { + Mouth of the abdomen open. { Cephalis with a + { variable number of + { porous tubes, 493. _Pylobotrys_. + + { Cephalis without + II. Subfamily Botryocampida. { porous tubes, 494. _Botryocampe_. + { + Mouth of the abdomen closed { Cephalis with a + by a lattice-plate. { variable number + { of porous tubes, 495. _Phormobotrys_. + + + +Genus 492. _Botryocyrtis_,[109] Ehrenberg, 1860, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 829. + +_Definition._--#Pylobotryida# without tubes on the cephalis, and with the +mouth of the abdomen open. + +The genus _Botryocyrtis_, founded by Ehrenberg upon two Indian species, is +the simplest among the Pylobotryida. It may have been derived from +_Botryopyle_ by the development of an abdomen (or a third shell-joint), the +mouth of which remains open. + + +1. _Botryocyrtis serpentis_, Ehrenberg. + + _Botryocyrtis serpentis_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 287, Taf. x. fig. 21. + +Cephalis quadrilobate; the odd frontal and the two paired buccal lobes +subspherical, about half as large as the odd occipital lobe. Thorax +inflated, about as long as the cephalis and half as long as the ovate +abdomen. Mouth of the latter constricted, of half the breadth. + +_Dimensions._--Length of the shell 0.12, breadth 0.06. + +_Habitat._--Indian Ocean (Zanzibar), depth 2200 fathoms, Pullen. + + +{1121}2. _Botryocyrtis theocampe_, n. sp. (Pl. 96, fig. 19). + +Cephalis quadrilobate; the odd frontal and the two paired buccal lobes +hemispherical, about half as large as the helmet-shaped occipital lobe. +Thorax cylindrical, of equal length and breadth, one and a half times as +broad as the cephalis and as the cylindrical abdomen. Pores rather large, +irregular, roundish. + +_Dimensions._--Length of the shell 0.12, breadth 0.06. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + +3. _Botryocyrtis cerebellum_, n. sp. (Pl. 96, fig. 18). + +Cephalis quinquelobate; the odd frontal and the two paired buccal lobes +ovate, about half as large as the two helmet-shaped paired occipital lobes +(?). Thorax campanulate, twice as broad and long as the cephalis and as the +truncate cylindrical abdomen. + +_Dimensions._--Length of the shell 0.12, breadth 0.08. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +4. _Botryocyrtis quinaria_, Ehrenberg. + + _Botryocyrtis quinaria_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 287, Taf. x. fig. 16. + +Cephalis quinquelobate; the odd occipital lobe ovate, twice as large as +each of the other four subspherical lobes, the two anterior (or frontal) of +which are somewhat smaller than the two posterior (or buccal). Thorax +campanulate, somewhat larger than the truncate abdomen. Pores rather large, +irregular. + +_Dimensions._--Length of the shell 0.09, breadth 0.05. + +_Habitat._--Indian Ocean (Zanzibar and Madagascar), surface. + + + +Genus 493. _Pylobotrys_,[110] Haeckel, 1881, Prodromus, p. 440. + +_Definition._--#Pylobotryida# with tubes on the cephalis, and with the +mouth of the abdomen open. + +The genus _Pylobotrys_ differs from the closely allied _Acrobotrys_, its +ancestral form, in the development of an abdomen or a third shell-joint, +the basal mouth of which remains open. + + +1. _Pylobotrys putealis_, n. sp. (Pl. 96, fig. 21). + +Cephalis multilobate, with a single curved and descending tube on the base +of its anterior part (sternal tube). Occipital half of the cephalis divided +into three large odd lobes (the largest {1122}the apical); facial half +divided into three to five lobes, an odd frontal and one or two lateral +pairs of small buccal lobes. Thorax truncate conical, about as large as the +cephalis and larger than the truncate abdomen. Pores regular circular. + +_Dimensions._--Length of the shell 0.12, breadth 0.08. + +_Habitat._--Tropical Atlantic Station 347, depth 2250 fathoms. + + +2. _Pylobotrys fontinalis_, n. sp. (Pl. 96, fig. 20). + +Cephalis trilobate, with three ovate lobes in the sagittal plane, of nearly +equal size, and two divergent cylindrical tubes conical at the base. An +ascending apical tube on the apex of the occipital lobe and a descending +sternal tube on the base of the frontal lobe. The middle lobe between the +former distinctly exhibits in the apical view (fig. 20) the collar septum +with the four cortinar pores. Thorax campanulate, larger than the cephalis +and the truncate abdomen. + +_Dimensions._--Length of the shell 0.11, breadth 0.06. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +3. _Pylobotrys cerebralis_, n. sp. (Pl. 96, fig. 22). + +Cephalis multilobate, with four divergent cylindrical tubes, which are +cylindrical, obliquely truncate at the mouth, and correspond in position to +the four typical spines of _Cortina_; an ascending apical tube and three +descending basal tubes (an odd caudal and two paired pectoral). The +helmet-shaped occipital lobe is about as large as the frontal half of the +cephalis, which is divided into three pairs of smaller pyriform lobes. +Thorax subspherical, about as large as the cephalis and half as large as +the inflated abdomen. Pores very scarce and small. + +_Dimensions._--Length of the shell 0.15, breadth 0.08. + +_Habitat._--Indian Ocean, Cocos Islands, Rabbe, surface. + + + +Genus 494. _Botryocampe_,[111] Ehrenberg, 1860, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 829. + +_Definition._--#Pylobotryida# without tubes on the cephalis, and with the +mouth of the abdomen closed. + +The genus _Botryocampe_ may be derived from _Botryocyrtis_ by development +of a basal lattice-plate, closing the terminal mouth of the abdomen. It is +at the same time closely allied to the Tricyrtid _Theocapsa_, and may be +perhaps derived from this by lobation of the cephalis. + + +{1123}1. _Botryocampe inflata_, Ehrenberg. + + _Botryocampe inflata_, Ehrenberg, 1861, Monatsber. d. k. Akad. d. Wiss. + Berlin, p. 296; Abhandl. d. k. Akad. d. Wiss. Berlin, 1872, p. 285, + Taf. ii. fig. 4. + + _Botryocampe inflata_, Haeckel, 1862, Monogr. d. Radiol., p. 345. + + _Lithobotrys inflata_, Bailey, 1856, Amer. Journ. Sci. and Arts, vol. + xxii. p. 1, pl. i. fig. 15. + +Cephalis trilobate, inflated, of about the same breadth and length as the +tun-shaped thorax and the hemispherical abdomen. Frontal lobes of the +cephalis ovate, a little smaller than the ovate odd occipital lobe. Pores +numerous and small. + +_Dimensions._--Length of the shell 0.05 to 0.08, breadth 0.02 to 0.04. + +_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Pacific, Stations 267 to +274, 241, 354, &c., surface, and in various depths. + + +2. _Botryocampe theocapsa_, n. sp. + +Cephalis trilobate, half as long as the campanulate thorax, and one-third +as long as the ovate abdomen. Frontal lobes subspherical, scarcely half as +long as the helmet-shaped occipital lobe. Pores very small and scarce. + +_Dimensions._--Length of the shell 0.12, breadth 0.04. + +_Habitat._--South Atlantic, Station 335, depth 1425 fathoms. + + +3. _Botryocampe galea_, Haeckel. + + _Lithobotrys galea_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 83. + + _Lithocorythium galea_, Ehrenberg, 1854, Mikrogeol., Taf. xxii. fig. 29, + a, b. + + _Lithocorythium galea_, Haeckel, 1862, Monogr. d. Radiol., p. 330. + +Cephalis quinquelobate, about as large as the ovate thorax, and twice as +large as the hemispherical abdomen (which is identical with the "crista +obtusa finis anterioris" of Ehrenberg). Occipital lobe helmet-shaped, about +twice as long as the two pairs of lateral lobes (the superior frontal and +the inferior buccal lobes). + +_Dimensions._--Length of the shell 0.08, breadth 0.04. + +_Habitat._--Fossil in Barbados. + + +4. _Botryocampe rotalia_, n. sp. (Pl. 96, fig. 23). + +Cephalis quinquelobate, half as large as the campanulate thorax and the +subspherical abdomen. Occipital lobe ovate, one and a half times as long as +the two ovate frontal lobes, and three times as long as the two +subspherical buccal lobes. Collar septum with six distinct cortinar pores +(two anterior jugular, two middle cardinal and two posterior cervical, fig. +23). + +_Dimensions._--Length of the shell 0.1, breadth 0.06. + +_Habitat._--South Pacific, Station 295, depth 1500 fathoms. + + +{1124}5. _Botryocampe camerata_, n. sp. (Pl. 96, fig. 24). + +Cephalis multilobate, about as long and half as broad as the irregularly +campanulate thorax, which is half as long as the subspherical large +abdomen. Occipital lobe of the cephalis helmet-shaped, larger than its +uviform frontal part, which is divided into six to eight small subspherical +lobes. In the interior of the thorax and abdomen irregularly branched rods +are visible, which divide their inner space into compartments or incomplete +chambers. Pores large, regular, circular, hexagonally framed. + +_Dimensions._--Length of the shell 0.15, breadth 0.09. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +Genus 495. _Phormobotrys_,[112] Haeckel, 1881, Prodromus, p. 440. + +_Definition._--#Pylobotryida# with tubes on the cephalis, and with the +mouth of the abdomen closed. + +The genus _Phormobotrys_ differs from the similar and closely allied +_Pylobotrys_ in the development of a basal lattice-plate closing the +terminal mouth of the thorax, and corresponds therefore to _Lithobotrys_ +among the Lithobotryida. As in the latter and in _Cannobotrys_, &c., so +here in _Phormobotrys_, different subgenera may be distinguished, according +to the different number and disposition of the radial tubes which become +developed from the lobate cephalis. + + +1. _Phormobotrys trithalamia_, n. sp. (Pl. 96, fig. 26). + +Cephalis trilobate, with a single apical tube, which is only one-third as +long, spindle-shaped, pointed, with frontal opening. Frontal lobes ovate, +two-thirds as long as the helmet-shaped occipital lobe. Internal frontal +septum of the cephalis with four large pores. Thorax cylindrical, twice as +long as the hemispherical abdomen. Pores small and numerous, irregular, +roundish. + +_Dimensions._--Length of the shell 0.16, breadth 0.05. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +2. _Phormobotrys pentathalamia_, n. sp. (Pl. 96, fig. 27). + +Cephalis quinquelobate, with a single conical apical tube of the same +length, which has an obliquely truncate frontal opening. Odd frontal and +paired buccal lobes smaller than the sternal and the occipital lobe. +Internal frontal septum with six large pores. Thorax inflated, a little +larger than the subspherical abdomen. Pores subregular, circular. + +_Dimensions._--Length of the shell 0.15, breadth 0.08. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +{1125}3. _Phormobotrys hexathalamia_, Haeckel. + + _Botryocampe hexathalamia_, Haeckel, 1862, Monogr. d. Radiol., p. 344, + Taf. xii. fig. 10. + +Cephalis sexlobate, with a single apical horn, which is solid, vertical, +cylindrical, pointed, only one-third as long. Frontal lobes subcylindrical, +nearly as long as the kidney-shaped occipital lobe, three to four times as +long as the small buccal lobes and the odd sternal lobe. Thorax tun-shaped, +smaller than the cephalis, larger than the hemispherical abdomen. Pores +numerous, subregular, circular. + +_Dimensions._--Length of the shell 0.13 to 0.15, breadth 0.05 to 0.06. + +_Habitat._--Mediterranean, Messina, surface. + + +4. _Phormobotrys cannothalamia_, n. sp. (Pl. 96, fig. 25). + +Cephalis trilobate, of about the same breadth and length as the campanulate +thorax, which is three times as long as the flat cap-shaped abdomen. The +middle (or central) lobe of the cephalis is simple, nearly cubical, and +smaller than the ovate occipital and frontal lobe. The two latter are +prolonged into two slender cylindrical divergent tubes. Pores small and +very numerous. + +_Dimensions._--Length of the shell 0.1, breadth 0.05. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +5. _Phormobotrys polythalamia_, n. sp. + +Cephalis multilobate, of the same length and breadth as the subspherical +thorax, and half as long as the ovate abdomen. Occipital lobe +helmet-shaped, about as large as the frontal half of the cephalis, which is +divided into six to eight lobes (two odd and two or three pairs of lateral +lobes). Four cylindrical tubes corresponding to the four typical spines of +_Cortina_, an ascending apical and three descending basal tubes (a +posterior caudal and two anterior pectoral). + +_Dimensions._--Length of the shell 0.14, breadth 0.08. + +_Habitat._--South Pacific, Station 298, depth 2225 fathoms. + + +{1126}---- + + +Suborder III. CYRTOIDEA, Haeckel, 1862. + + _Cyrtida_, Haeckel, 1862, Monogr. d. Radiol., pp. 272, 280. + _Cyrtoidea_ vel _Cyrtida_, Haeckel, 1881, Prodromus, pp. 425-439. + _Polycystina solitaria_, Ehrenberg, 1847, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, pp. 53, 54. + _Monodictya nassellaria_, Ehrenberg, 1875, Abhandl. d. k. preuss. Akad. + d. Wiss. Berlin, pp. 156, 157. + +_Definition._--NASSELLARIA with a complete lattice-shell, exhibiting a +simple or reduced cephalis, which is neither bilocular nor lobate, without +sagittal constriction. + +The order #Cyrtoidea#, described by me in 1862 as the family Cyrtida, is by +far the largest of all the main groups of Radiolaria, and remarkable from +the extraordinary variety of forms and the number of species. In the +following system more than eleven hundred species are described, comprising +about one-fourth of the number of species in the whole class of Radiolaria. +This astonishing variety, however, is not effected by development of a +large number of different types, but by an extraordinary variability within +certain restricted boundaries, similar to what is seen among insects and +birds. The number of genera, therefore, is comparatively small, and they +may all be disposed into four families only, which in my Monograph (1862, +p. 280) were distinguished as Monocyrtida, Dicyrtida, Tricyrtida and +Stichocyrtida. If we divide these four groups in the following pages into +twelve families and twenty-four subfamilies, we are guided by practical +considerations only, hoping thereby to give a better survey of the +difficult labyrinth of Cyrtoidean morphology. + +The #Cyrtoidea# are characterised by this wonderful richness of specific +forms not only in the present seas, but also for millions of years in the +former ages of our globe. The majority of all the fossil Radiolaria which +are now known belong to this group, and many species of it are so common +that great rocks are formed by their union. The fact was first observed by +Ehrenberg, who in his first system of _Polycystina_ (1847, _loc. cit._, p. +54) enumerated forty-four genera and two hundred and eighty-two species; +the #Cyrtoidea#, his Polycystina solitaria, form the preponderant majority +of the whole class, viz., twenty-five genera and one hundred and +ninety-three species. + +In this first system (of 1847), as well as in the last systematic table of +Ehrenberg (of 1875, _loc. cit._), the Cyrtida as "Polycystina solitaria" +are opposed to all other Radiolaria, as "Polycystina composita." The former +bear the definition "Testae siliceae spatio interno ample pervio, aut +passim levius transverse constricto"; the latter, however, "Testae siliceae +spatio interno celluloso aut strictura longitudinali constricto." In +reality these definitions are insufficient, and the conclusions which +Ehrenberg derived {1127}from the organisation of the Polycystina solitaria +and composita, were quite erroneous. So also are the definitions of the +three families into which he divided the Polycystina solitaria, afterwards +(in 1875) called by him "Monodictya nassellaria." These three families were +the Halicalyptrina, Lithochytrina and Eucyrtidina. With these were also +united the three genera of #Botryodea# known to Ehrenberg (_Lithobotrys_, +_Botryocampe_, _Botryocyrtis_). We entirely separate these here from the +true Cyrtida, on account of their lobate or multilocular cephalis. + +Whilst Ehrenberg only knew the skeleton of the Polycystina solitaria, the +first observations of living Cyrtida were published by Johannes Mueller, +1858, in his fundamental treatise. He gave the first description and +figures of the central capsule of this group, with the characteristic lobes +developed from its basal part; and of the pseudopodia radiating on all +sides (_loc. cit._, Taf. vi.). The forms described by him were all +Mediterranean, one Dicyrtid (_Lithomelissa mediterranea_), two Tricyrtids +(_Eucyrtidium zancleum_ and _Pterocanium charybdeum_), and one Stichocyrtid +(_Lithocampe tropeziana_). + +In my monograph (1862, p. 272-341) I gave a detailed description of all +known and some new Cyrtida, and characterised this family by the +fundamental monaxonial form of the shell, with two different poles (an +upper apical and a lower basal pole), and by the unipolar growth, beginning +from the apical pole. I pointed out also the peculiar structure of the +monaxonial central capsule. At that time I divided the Cyrtida into five +subfamilies, in which, however, the #Spyroidea# (= Zygocyrtida), and the +#Botryodea# (= Polycyrtida) were united with the true #Cyrtoidea# +(Monocyrtida, Dicyrtida, Stichocyrtida). + +The astonishing number of new and interesting forms of Cyrtida which I +found in the rich collection of the Challenger (beginning from 1876), and +mainly in the Radiolarian ooze of the Central Pacific (Stations 263 to +274), enabled me to give in my Prodromus, in 1881, a greatly enlarged and +amended system of this important group. I separated there the #Spyroidea# +(= Zygocyrtida), and the _Botryodea_ (= Polycyrtida) from the true +#Cyrtoidea# by restricted definition, pointing out the essential +differences in the structure of the cephalis in these groups of +#Cyrtellaria#. The latter name, as here used, is therefore identical with +the "Cyrtida" of my Monograph. In the Prodromus I divided the true Cyrtida +(p. 426) into five subfamilies and thirty tribes, corresponding to the +differences in the number of the shell-joints and of the radial apophyses, +and in the shape of the closed or open mouth. These groups are here +retained, but reduced to four families and twenty-four subfamilies, since +the Tetracyrtida are better united with the Stichocyrtida (compare below). + +Richard Hertwig in his work Organismus der Radiolarien (1879, pp. 74 to 86) +gave the first accurate description of the finer structure of the central +capsule of the Cyrtida, and pointed out their character as true MONOPYLEA, +with porochora and {1128}podoconus, and the peculiar shape of its nucleus. +He also published excellent figures of some interesting new species. + +O. Buetschli, 1882, in his valuable paper entitled: "Beitraege zur Kentniss +der Radiolarien-Skelette, insbesondere der der Cyrtida" (Zeitschr. fuer +wiss. Zool., vol. xxxvi. p. 485) made an attempt at a natural +classification of the Cyrtida, which he derived from the #Spyroidea# or +Zygocyrtida. As already mentioned above, we cannot accept this essay as the +foundation of a true natural system, since the affinities of the +#Cyrtellaria# (and of the NASSELLARIA as a whole) are far more complicated +and difficult than Buetschli supposed. His views were supported by accurate +observations only on the structure of the fossil #Cyrtoidea# of Barbados; +these, however, represent the minority only of the genera, and many +interesting and important forms (mainly of true "Monocyrtida") remained +unknown to Buetschli. A great part, however, of his observations are very +useful, and his remarks on comparative morphology are very suggestive. + +The #Cyrtoidea# may be divided into families and subfamilies according to +three different principles, viz., (1) the number of joints into which the +shell is divided by transverse strictures; (2) the number of radial +apophyses which arise from the shell; (3) the shape of the basal mouth, +which is either open or closed by a lattice-plate. At present every attempt +of classification in this large group must be more or less artificial, +since the affinities of the numerous smaller and larger groups are +extremely complicated, and the ontogeny, the only sure guide in this +phylogenetical labyrinth, is perfectly unknown. It seems therefore the most +convenient to employ for our artificial classification, first, the number +of shell-joints, second, the radial structure, and third, the shape of the +mouth. + +A. The number of joints into which the shell is divided by transverse +constrictions, serves here for the distinction of four primary groups or +suborders of the #Cyrtoidea#, viz., (1) Monocyrtida with one joint; (2) +Dicyrtida with two joints; (3) Tricyrtida with three joints; and (4) +Stichocyrtida with four or more joints. In my Prodromus (1881, p. 426) I +divided the latter group into Tetracyrtida (with four joints), and +Stichocyrtida (with five or more joints); but these two groups may be +united, since the fourth and all the succeeding joints are of rather +indifferent shape and of little morphological value. The three first +joints, however, are usually very different and possess a high +morphological importance, so that we distinguish the first joint as +cephalis, the second as thorax, and the third as abdomen. The uppermost +transverse constriction, which separates the two first joints, cephalis and +thorax, is the collar stricture and is usually caused by an internal +fenestrated septum, the cortinar septum. The second constriction, which +separates the second and third joints (thorax and abdomen) is called the +lumbar constriction. The following constrictions (in the Stichocyrtida) are +indifferent and of little morphological interest, and require therefore no +peculiar designation. + +{1129}B. The radial structure, indicated by radial apophyses arising from +the shell, offers three principal differences, according to which the whole +group of #Cyrtoidea# may be divided into three large groups or sections, +viz., (1) Pilocyrtida, or Cyrtoidea triradiata, with three radial +apophyses; (2) Astrocyrtida, or Cyrtoidea multiradiata, with numerous +radial apophyses (four to nine or more); and (3) Corocyrtida, or Cyrtoidea +eradiata, without external radial apophyses. The majority of #Cyrtoidea# +are Pilocyrtida, with three radial apophyses, which are probably homologous +to the three primary feet of the #Plectoidea# and of _Cortina_ (therefore +"cortinar feet"). The Astrocyrtida, or the #Cyrtoidea# with a variable +number of radial apophyses (at least four to six) may be derived from the +Pilocyrtida by interpolation of secondary or interradial apophyses between +the three primary or perradial apophyses. The Corocyrtida, however, or the +#Cyrtoidea# without external radial apophyses, may have originated by +reduction and loss of the latter, either from the Pilocyrtida or from the +Astrocyrtida. + +C. The shape of the basal mouth in the #Cyrtoidea# exhibits two essential +differences only, viz., (1) the terminal mouth of the shell is a simple +wide opening in the Stomocyrtida, or (2) the terminal mouth is closed by a +lattice-plate, in the Clistocyrtida. As these two different cases occur in +all the twelve families, which we have distinguished according to the +differences in the number of joints and in the radial structure, we get +altogether twenty-four subfamilies which are synoptically arranged in the +following table:-- + + +---------------------------+---------------------------------+ + | Synopsis of the four | | + | sections, twelve families | PILOCYRTIDA. | + |and twenty-four subfamilies| Cyrtoidea triradiata. | + | of CYRTOIDEA. | (Three radial apophyses.) | + +---------------------------+----------------+----------------+ + | Mouth of the shell. | _Aperta._ | _Clausa._ | + +---------------------------+----------------+----------------+ + | MONOCYRTIDA. | TRIPOCALPIDA. | + |(Cyrtoidea monothalamia). | Archipilida. | Archiperida. | + +---------------------------+----------------+----------------+ + | DICYRTIDA. | TRIPOCYRTIDA. | + |(Cyrtoidea dithalamia). | Sethopilida. | Sethoperida. | + +---------------------------+----------------+----------------+ + | TRICYRTIDA. | PODOCYRTIDA. | + | (Cyrtoidea trithalamia). | Theopilida. | Theoperida. | + +---------------------------+----------------+----------------+ + | STICHOCYRTIDA. | PODOCAMPIDA. | + |(Cyrtoidea polythalamia). | Stichopilida. | Stichoperida. | + +---------------------------+---------------------------------+ + | | ASTROCYRTIDA. | + | | Cyrtoidea multiradiata. | + | |(Four to nine or more apophyses.)| + +---------------------------+----------------+----------------+ + | Mouth of the shell. | _Aperta._ | _Clausa._ | + +---------------------------+----------------+----------------+ + | MONOCYRTIDA. | PHAENOCALPIDA. | + |(Cyrtoidea monothalamia). | Archiphormida. | Archiphaenida. | + +---------------------------+----------------+----------------+ + | DICYRTIDA. | ANTHOCYRTIDA. | + |(Cyrtoidea dithalamia). | Sethophormida. | Sethophaenida. | + +---------------------------+---------------------------------+ + | TRICYRTIDA. | PHORMOCYRTIDA. | + | (Cyrtoidea trithalamia). | Theophormida. | Theophaenida. | + +---------------------------+----------------+----------------+ + | STICHOCYRTIDA. | PHORMOCAMPIDA. | + |(Cyrtoidea polythalamia). | Stichophormida.| Stichophaenida.| + +---------------------------+----------------+----------------+ + | | COROCYRTIDA. | + | | Cyrtoidea eradiata. | + | | (No radial apophyses.) | + +---------------------------+----------------+----------------+ + | Mouth of the shell. | _Aperta._ | _Clausa._ | + +---------------------------+----------------+----------------+ + | MONOCYRTIDA. | CYRTOCALPIDA. | + |(Cyrtoidea monothalamia). | Archicorida. | Archicapsida. | + +---------------------------+----------------+----------------+ + | DICYRTIDA. | SETHOCYRTIDA. | + |(Cyrtoidea dithalamia). | Sethocorida. | Sethocapsida. | + +---------------------------+---------------------------------+ + | TRICYRTIDA. | THEOCYRTIDA. | + | (Cyrtoidea trithalamia). | Theocorida. | Theocapsida. | + +---------------------------+----------------+----------------+ + | STICHOCYRTIDA. | LITHOCAMPIDA. | + |(Cyrtoidea polythalamia). | Stichocorida. | Stichocapsida. | + +---------------------------+----------------+----------------+ + +{1130}The cephalis, or the first shell-joint of the #Cyrtoidea#, is in the +majority homologous with the cephalis of the #Spyroidea#, from which it +differs in the reduction of the sagittal ring and the absence of the +corresponding sagittal constriction; its cavity is therefore simple, not +bilocular. Its homology with the original cephalis of the #Spyroidea# +cannot be doubted, when its base exhibits the typical basal pores of the +Semantida. But in many cases these are wanting, and in a great number of +#Cyrtoidea# (mainly of Monocyrtida) there is more or less evidence that the +original cephalis is lost, and that the real first joint is the thorax, the +original second joint. At present it is quite impossible to distinguish +between the former and the latter shells, and therefore in the following +descriptions the first joint is always named cephalis and the second +thorax. In future, when the affinities of the #Cyrtoidea# become better +known, it will be necessary to distinguish the "Archicephalis," or true +cephalis of all #Spyroidea# and of the majority of #Cyrtoidea#, from the +"Pseudocephalis" or the false cephalis of the minority (_e.g._, of many +Monocyrtida aperta, Archipilida, Archiphormida, Archicorida, &c.). + +The thorax, or the second shell-joint of the #Cyrtoidea#, is in the +majority homologous with the thorax of the Phormospyrida and Androspyrida, +and therefore developed by apophyses, which arise from the base of the +cephalis and become united by transverse branches forming a lattice-plate. +Its size is generally in inverse proportion to that of the cephalis. The +more the cephalis becomes reduced, the more the thorax is developed. Its +form is very variable, usually three-sided pyramidal or prismatic in the +triradiate, polyhedral in the multiradiate, and conical or cylindrical in +the eradiate #Cyrtoidea#. Its terminal mouth is either a simple wide +opening, or closed by a lattice-plate. In the majority of #Cyrtoidea# the +thorax is separated from the cephalis not only by the external collar +constriction, but also by the internal cortinar septum, a horizontal +lattice-plate which exhibits the typical basal pores of the Semantida +(usually two smaller jugular and two larger cardinal pores). But this +septum is often reduced or perfectly lost, and then the external collar +constriction alone indicates the separation of the cephalis and the thorax. + +The abdomen, or the third shell-joint of the #Cyrtoidea#, absent in the +Monocyrtida and Dicyrtida (as also in all #Spyroidea#), occurs constantly +in all Tricyrtida and Stichocyrtida. It is a simple large chamber in the +Tricyrtida, but forms an annulated body, composed of a variable number of +successive joints, in the Stichocyrtida. The constrictions between these +joints, and also the lumbar constriction, between abdomen and thorax, are +usually provided with a lattice-girdle, projecting into the cavity of the +shell, like a diaphragm. Usually this horizontal girdle bears only a single +circle of pores, rarely two or more. In many #Cyrtoidea# it is replaced by +a solid horizontal ring of silex, and often it is wanting. It originates by +the insertion of the following shell-joint, which takes place not on the +terminal mouth of the preceding joint, but somewhat above it. + +{1131}The annular joints of the Stichocyrtida succeeding the third joint, +and very variable in number, may be regarded either as a series of new +postabdominal chambers, succeeding the true abdomen, or as secondary joints +of the annulated abdomen itself. The latter view may be sustained by the +fact that these joints are usually of an indifferent shape, and do not +possess the characteristic features which we find in the first three +joints, the abdomen, the thorax and the cephalis. + +The lattice-work of the shell exhibits in the #Cyrtoidea# an extraordinary +variety, similar to that of the #Sphaeroidea#; it serves in the first place +for the distinction of species. The three first joints of the shell are +often distinguished by the different character of the lattice-work. The +cephalis has usually very small and simple pores. The lattice-work of the +thorax is often characterised by radial structures. The pores of the +abdomen are usually very numerous and regular. The numerous joints in the +annulated abdomen of the Stichocyrtida commonly exhibit little variety. + +The closure of the mouth, effected by a convex or horizontal terminal +lattice-plate, has a different signification in the Monocyrtida and in the +jointed #Cyrtoidea#. In the Monocyrtida clausa this closing plate is the +original cortinar plate or the basal plate of the cephalis. In the jointed +#Cyrtoidea#, however, the lattice-plate which closes the terminal mouth of +the thorax or of the abdomen (of the last annular joint in the +Stichocyrtida), is produced by central union of the convergent edges, which +grow centripetally from the margin of the mouth of the last joint towards +its centre. + +The radial apophyses arising from the shell of the #Cyrtoidea# may probably +be always derived from that tripodal structure which is found in all +#Plectoidea#, in _Cortina_ and _Cortiniscus_ among the #Stephoidea#, and in +the majority of #Spyroidea#. Therefore the prototype of this radial +structure would be _Plagoniscus_ and _Cortina_, with four radial spines +united in a common point, the cortinar centrum; an ascending apical horn +and three descending basal feet. The odd posterior or caudal foot is +usually similar in shape to the two paired anterior or pectoral feet, but +may be distinguished from these latter by its relation to the apical horn. +Very frequently an internal vertical free columella arises in the cephalis, +or instead of it an ascending rib in the dorsal wall of the cephalis, which +connects the base of the apical horn with the origin of the caudal foot. +This is probably the remaining part of the sagittal ring. More rarely also +a part of the ventral rod of the latter is preserved, or on the anterior +pole of the basal rod of the cephalis an ascending procolumella arises +which is inserted on the frontal face of the cephalis, and sometimes +prolonged into a nasal horn (the rod, C, of Buetschli). These two odd +horns, the posterior apical horn and the anterior nasal horn, are usually +different and divergent. In some genera a variable number of accessory +radial horns is developed on the convex face of the cephalis. In many +hornless genera the free apical horn is lost, but not unfrequently the +columella is preserved which connects the caudal foot with that point of +the cephalis, in which formerly the apical horn was inserted. + +{1132}The three primary radial beams, corresponding to the three basal feet +of _Plectaniscus_ and _Cortina_, exhibit in the #Cyrtoidea# the greatest +variety in form and size, and chiefly in their relation to the shell, the +latter serving mainly for the distinction of genera. Originally these three +cortinar beams arise from the basal plate of the cephalis, the odd caudal +foot appearing as a prolongation of the basal rod of that plate, and the +paired pectoral feet as prolongations of its coracal rods (between the +jugular and cardinal pores). The lattice-work of the thorax is developed +usually between the three cortinar feet, more rarely inside or outside of +them. Therefore the three beams appear commonly as three divergent ribs in +the wall of the thorax, and continue over its basal mouth as three free +terminal feet. With the increasing length of the shell and the number of +its joints the three radial ribs are also prolonged, and their free distal +ends may be prominent at very different points, either as three lateral +wings or as three terminal feet. These are either solid spines or +lattice-plates, sometimes more or less ramified. + +The three radial apophyses are prevalent in the majority of the +#Cyrtoidea#, which we call "Pilocyrtida" (or Cyrtoidea triradiata). Their +number increases in the Astrocyrtida (or Cyrtoidea multiradiata). The most +frequent cases of multiplication are here caused by the development of six +or nine radial apophyses; these may be enclosed ribs, or lateral wings, or +terminal feet. In the sexradial #Cyrtoidea# there are three secondary or +interradial apophyses interpolated between the three primary or perradial; +in the nine-radial #Cyrtoidea#, however, there are six adradial apophyses +interpolated. + +A third and last great group is formed by the Corocyrtida or Cyrtoidea +eradiata. These exhibit no radial apophyses, neither enclosed ribs, nor +free lateral wings, nor terminal feet. But in a great number of them +internal traces of an original triradiate structure are visible, mainly in +the cortinar septum between cephalis and thorax; this often exhibits three +or four, and sometimes six cortinar or collar pores, of the same typical +shape as in the triradial #Spyroidea#. Sometimes even an internal columella +with three radial branches is preserved, as in _Axocorys_. It is therefore +very probable that a great part of these Cyrtoidea eradiata (if not all) +may be derived from triradiate or multiradiate ancestral forms, by +reduction and loss of the radial apophyses. In another part of this group, +mainly in the Monocyrtida eradiata (Cyrtocalpida) it is possible, or even +probable, that their eradiate shell has originated independently from +Nassellida, and that they have no true relation to radial #Cyrtoidea#. + +_The Central Capsule_ of the #Cyrtoidea#, first observed by J. Mueller +(1858), and more fully described in my Monograph (1862), was very +accurately examined by Richard Hertwig (1879). His observations were +confirmed by numerous new forms, which I was able to examine in +well-preserved preparations of the Challenger. The central capsule, +according to these, exhibits the same typical shape, which is +characteristic of all MONOPYLEA (with porochora and podoconus), and may be +derived with the latter from the common ancestral forms, _Cystidium_ and +_Nassella_ (= the skeletonless Nassellida). In {1133}the majority, however, +of #Cyrtoidea#, the capsule develops on its basal face a number of +depending lobes, as were also found in some #Spyroidea# (and probably also +#Botryodea#). In this respect we may distinguish two main forms of the +capsule in the #Cyrtellaria#, viz., the primary simple, not lobate form, +and the secondary lobate form. The central capsule is originally always +enclosed in the cephalis, and has there a simple, subspherical, ellipsoidal +or ovate form. As soon as their growth increases, and the enclosing +cephalis becomes too narrow, it sends out prolongations in the form of +basal lobes, which depend from its base, and proceed through the pores of +the basal lattice of the cephalis, or the cortinar pores. In the great +majority of #Cyrtoidea# in which the capsule was observed, either three or +four such lobes were seen (already described by J. Mueller). Of course this +number depends upon the number of cortinar pores, which is either three or +four; therefore in the #Cyrtoidea# with three pores in the cortinar plate, +we find three lobes of the central capsule (an odd posterior and two paired +anterior); in the #Cyrtoidea#, however, with four pores in the cortinar +plate (the majority) we find four lobes of the central capsule (two smaller +anterior jugular and two larger posterior cardinal lobes). Usually each +lobe is ovate or pear-shaped and encloses a large oil-globule, and often +also an apophysis of the cell-nucleus. + + +---- + + +Section I. MONOCYRTIDA, Haeckel, 1862, Monogr. d. Radiol., pp. 280, 281. + +_Definition._--Cyrtoidea monothalamia, with simple, not jointed shell (or +cephalis), without transverse constrictions. + +_Synopsis of the three Families and six Subfamilies of Monocyrtida._ + + Family LIX. Tripocalpida. } Mouth open, 1. Archipilida. + } + Three radial apophyses. } Mouth closed, 2. Archiperida. + + Family LX. Phaenocalpida. } Mouth open, 3. Archiphormida. + } + Numerous radial apophyses. } Mouth closed, 4. Archiphaenida. + + Family LXI. Cyrtocalpida. } Mouth open, 5. Archicorida. + } + No radial apophyses. } Mouth closed, 6. Archicapsida. + + + +Family LIX. #TRIPOCALPIDA#, n. fam. + + _Archipilida et Archiperida_, Haeckel, 1881, Prodromus, pp. 427, 429. + +_Definition._--Monocyrtida triradiata. (#Cyrtoidea# with a simple, not +jointed shell, representing a simple cephalis, with three radial +apophyses.) + +{1134}The family Tripocalpida, composed of the Archipilida and Archiperida +of my Prodromus, comprises those #Cyrtoidea# in which the lattice-shell is +quite simple, without transverse constriction, and bears three radial +apophyses. The two subfamilies differ in the shape of the basal mouth, +which in the Archipilida is a simple wide opening, in the Archiperida +closed by a lattice-plate; the former are here divided into eight, the +latter into seven different genera. + +Only three species of this family were hitherto described, all three +belonging to the Archipilida, viz., (1) _Tripocalpis galea_ (fossil in +Barbados, figured by Ehrenberg, 1875, as _Halicalyptra galea_), (2) +_Tripodiscium campanula_ (fossil in Sicily, figured by Stoehr, 1880, as +_Carpocanium_); and (3) _Tridictyopus elegans_, of which Richard Hertwig +gave an excellent description in 1879, with an accurate figure of the +central capsule. All the other species of the family (seventy) are new. + +The shell in the majority of Tripocalpida is ovate or campanulate, +sometimes conical or three-sided pyramidal. Three radial apophyses are +constantly distinct, either three lateral wings or three terminal feet; +these are usually solid spines, rarely lattice-plates. The top of the shell +usually bears an apical horn, rarely two or more horns; often the horn is +wanting. The lattice-work of the shell is very various in the different +species, and often of a remarkable structure (Pl. 51, figs. 6-8; Pl. 98, +figs. 4-8). The cavity of the shell is in all Archipilida, and in a part of +the Archiperida (_Peridium_, _Archipera_, _Archibursa_) quite simple. In +the other part of the Archiperida, however, constituting the peculiar group +of Euscenida (genera 504-507), a vertical columella arises in the centre of +the basal plate, and is prolonged upwards in the apical horn; this +columella is either simple (_Euscenium_, _Archiscenium_) or branched +(_Cladoscenium_, _Pteroscenium_); in the latter case the ascending branches +are disposed in triradiate verticils and are inserted on the inner face of +the shell (compare Pl. 53, figs. 11-16, and Pl. 98, figs. 1-4). + +The phylogenetic origin of the Tripocalpida may be very divergent, and +their morphological affinity to the other #Nassellaria# is a very +complicated problem. The Euscenida (genera 504-507) may be derived directly +from the Plagonida (_Plagoniscus_) or Plectanida (_Plectaniscus_). The +Archibursida (genera 508-510) however, manifest a closer affinity to the +Tripospyrida, and may be derived from them by reduction of the sagittal +ring and constriction. In these two groups of Archiperida the shell may be +regarded as a true cephalis. In the Archipilida, however, where the shell +has a wide basal opening and the three radial ribs arise originally from +the base of the apical horn, the shell itself may correspond to the thorax +of the Dicyrtida, and may be derived from these by loss of the cephalis. +This is the more probable, as sometimes a small remnant of the reduced +cephalis is preserved (Pl. 98, fig. 8). None of these difficult questions +can be answered until a much closer morphological knowledge of the +Tripocalpida is acquired. + +{1135}_Synopsis of the Genera of Tripocalpida._ + + ------------------------------------------------------------------------- + I. Subfamily Archipilida. Basal mouth of the shell a simple wide opening. + -------------------- + Shell with three lateral ribs or wings, with or without terminal feet. + ------------------------------------------------------------------------- + { Apex with a horn, 496. _Tripocalpis_. + Three terminal feet. { + { No apical horn, 497. _Tripodonium_. + + Six to nine or more } No apical horn, 498. _Tripterocalpis_. + terminal feet. } + + No terminal feet. { Apex with a horn, 499. _Trissopilium_. + { + { No apical horn, 500. _Archipilium_. + ------------------------------------------------------------------------- + Shell without lateral ribs or wings but with three terminal feet. + ------------------------------------------------------------------------- + Feet simple or } Apex with a horn, 501. _Tripilidium_. + branched, not latticed. } + } No apical horn, 502. _Tripodiscium_. + + Feet latticed. Apex with a horn, 503. _Tridictyopus_. + ------------------------------------------------------------------------- + II. Subfamily Archiperida. + Basal mouth of the shell closed by a lattice-plate. + -------------------- + Shell in its axis with a free (simple or branched) internal + columella, + prolonged into an apical horn. + ------------------------------------------------------------------------- + Shell with three } Columella simple, 504. _Euscenium_. + free feet, without } + lateral lattice-wings. } Columella branched, 505. _Cladoscenium_. + + Shell with three } Columella simple, 506. _Archiscenium_. + lateral lattice-wings, } + connecting the three } Columella branched, 507. _Pteroscenium_. + feet with the horn. } + ------------------------------------------------------------------------- + Shell with simple cavity, without free columella. Three free basal feet. + ------------------------------------------------------------------------- + One apical horn, 508. _Peridium_. + + Two or more horns, 509. _Archipera_. + + No apical horn, 510. _Archibursa_. + + + +Subfamily 1. ARCHIPILIDA, Haeckel, 1881, Prodromus, p. 427. + +_Definition._--#Tripocalpida# with the basal mouth of the shell open (vel +Monocyrtida triradiata aperta). + + + +Genus 496. _Tripocalpis_,[113] Haeckel, 1881, Prodromus, p. 428. + +_Definition._--#Archipilida# (vel Monocyrtida triradiata aperta) with three +lateral ribs prolonged into three terminal feet. Apex with a horn. + +The genus _Tripocalpis_ opens the series of Archipilida, or of those +Monocyrtida in which the monothalamous shell exhibits a distinct triradial +structure, and a simple open mouth, without cortinar lattice. _Tripocalpis_ +is probably the most primordial of the Archipilida, and has three lateral +ribs, which are prolonged into three free terminal {1136}feet, and +connected in the apex of the pyramidal or campanulate shell with the apical +horn. It may probably be derived from _Dictyophimus_ by loss of the +cephalis. The central capsule is simple, spherical, or ellipsoidal. + + +1. _Tripocalpis plectaniscus_, n. sp. + +Shell three-sided pyramidal, smooth, about as long as broad, with irregular +polygonal pores and thin bars. Apical horn stout, three-sided pyramidal, +about as long as the shell. From the three edges of its base arise three +prominent straight radial ribs, which are prolonged into three large +divergent feet, of equal size and the same form as the horn. + +_Dimensions._--Shell 0.1 diameter, horn and feet 0.12. + +_Habitat._--Tropical Pacific (Philippine Sea), Station 206, depth 2100 +fathoms. + + +2. _Tripocalpis galea_, Haeckel. + + _Halicalyptra galea_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 74, Taf. ii. fig. 10. + +Shell campanulate, rough, about as long as broad, with irregular roundish +pores and thick bars. Apical horn stout, three-sided pyramidal, scarcely +one-fourth as long as the shell. Beyond its base there arise three +prominent, slightly curved lateral ribs, which are prolonged into three +pyramidal, slightly divergent stout feet, somewhat shorter than the shell. + +_Dimensions._--Shell 0.08 to 0.09 diameter, horn 0.02, feet 0.07. + +_Habitat._--Fossil in Barbados. + + +3. _Tripocalpis tricostata_, n. sp. + +Shell ovate campanulate, one and a half times as long as broad, with +regular circular pores, disposed in alternate longitudinal rows. Apical +horn three-sided pyramidal, stout, half as long as the shell. In the middle +of the shell there arise three wing-like lateral ribs, which are prolonged +into three broad, slightly curved, divergent terminal feet. + +_Dimensions._--Shell 0.12 long, 0.08 broad, horn and feet 0.06 to 0.08. + +_Habitat._--Fossil in Barbados. + + +4. _Tripocalpis triserrata_, n. sp. (Pl. 51, fig. 6). + +Shell ovate, nearly twice as long as broad. The three sides of the shell, +between the three large ribs, are provided each with nine delicate +parallel, longitudinal, slightly curved ribs, alternating with ten +longitudinal rows of regular circular pores about as broad as the bars. +Apical horn short and broad, three-sided pyramidal; from the three edges of +its base there arise three wing-like serrate main ribs, which are prolonged +into three short pyramidal terminal feet. + +_Dimensions._--Shell 0.12 long, 0.07 broad, horn and feet 0.01. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +{1137}5. _Tripocalpis cortinaris_, n. sp. (Pl. 97, fig. 3). + +Shell hemispherical, one and a half times as broad as long, with regular, +circular, hexagonally framed pores, Apical horn stout, three-sided +pyramidal, with three serrate edges. From the base of the latter arise +three strongly dentate and curved lateral ribs, with recurved teeth, and +these are prolonged into the serrate convex edge of the three basal feet, +which are crescentic and twice as long as the shell. + +_Dimensions._--Shell 0.07 long, 0.1 broad; horn 0.06 long, feet 0.14 long. + +_Habitat._--Indian Ocean, Cocos Islands (Rabbe), surface. + + + +Genus 497. _Tripodonium_,[114] Haeckel, 1881, Prodromus, p. 428. + +_Definition._--#Archipilida# (vel Monocyrtida triradiata aperta) with three +lateral ribs prolonged into three terminal feet. Apex without horn. + +The genus _Tripodonium_ differs from the preceding _Tripocalpis_, its +probable ancestral form, only in the loss of the apical horn (already very +small in some forms of the latter). It bears therefore to the latter the +same relation that _Sethopilium_ does to _Dictyophimus_. + + +1. _Tripodonium campanulatum_, n. sp. + +Shell campanulate, somewhat broader than high, with regular circular pores, +twice as broad as the bars. Three broad lateral wings, lamellar, +triangular, are prolonged over the peristome into three short triangular +lamellar feet one-fourth as long as the shell. + +_Dimensions._--Shell 0.08 long, 0.09 broad; feet 0.02 long. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +2. _Tripodonium ovatum_, n. sp. + +Shell ovate, one and one-third times as long as broad, with numerous and +small circular pores, scarcely as broad as the bars. Three prominent +longitudinal ribs, arising in the lower half of the shell-wall, are +prolonged into three divergent conical curved feet, about half as long as +the shell. + +_Dimensions._--Shell 0.12 long, 0.09 broad; feet 0.06 long. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + + +Genus 498. _Tripterocalpis_,[115] Haeckel, 1881, Prodromus, p. 428. + +_Definition._--#Archipilida# (vel Monocyrtida triradiata aperta) with three +lateral wings and a peristomial corona of numerous terminal feet. Shell +ovate, with constricted mouth, without apical horn. + +{1138}The genus _Tripterocalpis_ is distinguished from the other +Archipilida by the remarkable combination of three lateral wings and of +numerous (six to nine or more) terminal feet. It may be derived directly +from the preceding _Tripocalpis_ by multiplication of the terminal feet. +These are sometimes obliquely directed. The central capsule is ellipsoidal +or ovate, and fills up the greater part of the shell. + + +1. _Tripterocalpis phylloptera_, n. sp. (Pl. 51, fig. 1). + +Shell slender, ovate, nearly twice as long as broad. Pores circular, of +different sizes and at unequal distances. Along the lower half of the shell +there arise three broad triangular lamellar wings. Peristome with twelve +conical, nearly parallel and vertical feet, about one-sixth as long as the +shell. + +_Dimensions._--Shell 0.2 long, 0.12 broad; wings 0.1 long, feet 0.03 long. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +2. _Tripterocalpis conoptera_, n. sp. (Pl. 51, fig. 2). + +Shell ovate, nearly as broad as long. Pores regular, circular, quincuncial, +twice as broad as the bars. In the middle of the shell there arise three +conical, smooth, divergent wings, about half as long as the shell. +Peristome with six short triangular, oblique, convergent feet. + +_Dimensions._--Shell 0.16 long, 0.14 broad; wings 0.09 long; feet 0.02 +long. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +3. _Tripterocalpis ogmoptera_, n. sp. (Pl. 51, figs. 3-5). + +Shell ovate, nearly as broad as long. Pores small and numerous, circular or +roundish, partly confluent, double-contoured (fig. 4). In the middle of the +shell there arise three very large conical divergent wings, which are +longitudinally striped and longer than half the shell. Peristome with nine +short triangular, oblique, convergent feet. + +_Dimensions._--Shell 0.18 long, 0.16 broad; wings 0.12 long, feet 0.02 +long. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +Genus 499. _Trissopilium_,[116] Haeckel, 1881, Prodromus, p. 427. + +_Definition._--#Archipilida# (vel Monocyrtida triradiata aperta) with three +lateral ribs or wings. Mouth smooth, without terminal feet. Apex with a +horn. + +The genus _Trissopilium_ and the following nearly allied _Archipilium_ +differ from the other Archipilida in the absence of terminal feet, the +peristome being quite simple, and truncate. But there are three lateral +wings, arising either from the apex or from the lateral sides of the +monothalamous shell. _Trissopilium_ may perhaps be derived from +_Lithomelissa_ by reduction of the cephalis. + + +{1139}1. _Trissopilium tetraplecta_, n. sp. + +Shell in the upper half three-sided pyramidal, in the lower half inversely +hemispherical, of equal length and breadth. Pores irregular, roundish, in +the upper half larger. From the apex there diverge four equal, straight and +stout, three-sided pyramidal spines, one of which is vertically ascending +(the horn), the three others obliquely descending (the wings). The distal +half of the latter is free, whilst the proximal half forms three ribs, +enclosed in the shell-wall. Mouth constricted, half as broad as the shell. + +_Dimensions._--Shell 0.08 long and broad, horn and wings 0.1 long. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +2. _Trissopilium lithomelissa_, n. sp. + +Shell ovate, one and one-third times as long as broad. Pores circular, of +different sizes, small and numerous. Apical horn very large, straight, +cylindrical, vertical, longer than the shell. Three lateral wings shorter, +arising from the middle of the shell, conical, curved, divergent. Mouth +truncate, two-thirds as broad as the shell. + +_Dimensions._--Shell 0.11 long, 0.08 broad; horn 0.13 long, wings 0.09 +long. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +Genus 500. _Archipilium_,[117] Haeckel, 1881, Prodromus, p. 427. + +_Definition._--#Archipilida# (vel Monocyrtida triradiata aperta) with three +lateral ribs or wings. Mouth truncate, without terminal feet. Apex without +horn. + +The genus _Archipilium_ differs from the nearly allied _Trissopilium_, its +probable ancestral form, in the absence of the apical horn. The three +lateral wings of the ovate shell are stout spines. It may also be derived +from the similar _Sethopilium_ by reduction and loss of the cephalis. + + +1. _Archipilium orthopterum_, n. sp. (Pl. 98, fig. 7). + +Shell ovate, smooth, nearly cylindrical, scarcely broader than the +truncate, widely open mouth. Pores numerous, irregular, roundish, of very +different sizes. Three lateral wings arising from the middle zone, twice as +long as the shell, straight, divergent, stout, cylindrical, longitudinally +striped. + +_Dimensions._--Shell 0.08 long, 0.06 broad; wings 0.15 long. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +2. _Archipilium sigmopterum_, n. sp. + +Shell ovate, smooth, nearly campanulate, of equal length and breadth, one +and one-third times as broad as the truncate, slightly constricted mouth. +Pores scarce, irregularly formed and {1140}scattered, of very different +sizes. Three lateral wings, stout, prismatic, about as long as the shell +widely divergent and S-shaped, curved. + +_Dimensions._--Shell 0.08 diameter, wings 0.08 long. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +3. _Archipilium cyrtopterum_, n. sp. + +Shell ovate, rough, twice as broad as the constricted mouth. Pores small +and numerous, subregular, circular, smaller than the bars. Three lateral +wings cylindrical, crescentic, in the upper half divergent, in the lower +convergent, one and one-half times as long as the shell. + +_Dimensions._--Shell 0.09 long, 0.07 broad; wings 0.14 long. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + + +Genus 501. _Tripilidium_,[118] Haeckel, 1881, Prodromus, p. 428. + +_Definition._--#Archipilida# (vel Monocyrtida triradiata aperta) without +lateral ribs, with three simple or branched terminal feet and an apical +horn. + +The genus _Tripilidium_ differs from _Tripodonium_ in the absence of the +three lateral ribs, and may be derived either from this ancestral form, or +directly from _Tripospyris_ (by loss of the sagittal ring and +constriction); perhaps also from _Lychnocanium_ (by reduction of the +cephalis). We distinguish as two subgenera, _Tristylocorys_ (with simple +feet) and _Tripodocorys_ (with branched feet). + + + +Subgenus 1. _Tristylocorys_, Haeckel. + +_Definition._--Feet simple, not branched. + + +1. _Tripilidium cortina_, n. sp. + +Shell campanulate, rough, about as long as broad. Pores subregular, +circular, larger in the middle zone, twice to three times as broad as the +bars. Mouth constricted, half as broad as the shell. Apical horn straight +and stout, three-sided pyramidal, about as long as the shell. Three feet +divergent, slightly S-shaped, curved, somewhat longer the the shell. + +_Dimensions._--Shell 0.1 diameter, horn 0.09 long, feet 0.13 long. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +2. _Tripilidium hemisphaericum_, n. sp. + +Shell hemispherical, smooth, nearly twice as broad as long. Pores large, +with thin bars, irregular, roundish, of very different sizes. Mouth wide +open. Apical horn conical, half as long as {1141}the shell. Three feet +slender cylindrical, widely divergent, curved, nearly twice as long as the +shell. + +_Dimensions._--Shell 0.08 long, 0.14 broad; horn 0.05 long, feet 0.15 long. + +_Habitat._--South Pacific, Station 298, depth 2225 fathoms. + + +3. _Tripilidium lychnocanium_, n. sp. + +Shell hemispherical, thorny, one and a half times as broad as long. Pores +regular, circular, hexagonally framed, as broad as the bars. Mouth slightly +constricted. Apical horn stout and short, three-sided pyramidal. Three feet +cylindrical, straight, divergent, twice to three times as long as the +shell. (Similar to _Lychnocanium favosum_, Pl. 61, fig. 6, perhaps derived +from it by reduction of the cephalis.) + +_Dimensions._--Shell 0.08 long, 0.12 broad; horn 0.02 long, feet 0.2 long. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +4. _Tripilidium ovatum_, n. sp. + +Shell ovate, smooth, one and one half times as long as broad. Pores +regular, circular, as broad as the bars. Mouth constricted, half as broad +as the shell. Horn short, conical. Three feet conical, curved, convergent, +scarcely one-third as long as the shell. + +_Dimensions._--Shell 0.15 long, 0.11 broad; horn 0.02 long, feet 0.04 long. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +5. _Tripilidium clavatum_, n. sp. + +Shell nearly spherical, tuberculate, a little broader than long. Pores +regular, circular, as broad as the bars. Mouth constricted, half as broad +as the shell. Apical feet and the three divergent feet of equal size and +similar form, about as long as the shell, straight, in the basal half +smooth, cylindrical, in the distal half club-shaped, dimpled. (Very similar +to _Tripospyris conifera_ and _Tripospyris eucolpos_, Pl. 84, figs. 7 and +4; but the spherical shell exhibits no trace of sagittal ring or +constriction, and the simple shell-cavity has a wide open mouth, and is not +closed by a basal plate.) + +_Dimensions._--Shell 0.1 diameter, horn and feet 0.08 to 0.09 long. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +6. _Tripilidium costatum_, n. sp. (Pl. 98, figs. 8, 8_a_, 8_b_). + +Shell ovate, spinulate and costate, nearly twice as broad as long. Surface +with fifteen to twenty prominent longitudinal ribs, which are convergent +towards each pole and elegantly denticulate. The deep furrows between them +are divided by delicate, parallel, transverse ribs into numerous short and +broad dimples (thirty to forty in each furrow); each dimple contains a +small pore, like a transverse {1142}fissure. The apex bears a short and +stout, three-sided pyramidal horn, the hollow base of which is closed by a +small cortinar septum with three collar pores (fig. 8_b_). This seems to +indicate a rudimentary cephalis and the derivation of this species from +_Lychnocanium_ (Pl. 61). Peristome constricted, only one-fourth as broad as +the shell, with three short, conical, nearly vertical feet. The central +capsule (fig. 8_a_) in the specimen examined was well preserved, +hemispherical, not lobate, and filled up the upper half of the shell-cavity +(beyond the rudiment of the cortinar septum). + +_Dimensions._--Shell 0.2 long, 0.12 broad; horn 0.01 long, feet 0.02 long. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms. + + +7. _Tripilidium elongatum_, n. sp. + +Shell elongate, smooth, nearly cylindrical, in the upper third conical. +Pores small and numerous, regular, circular, half as broad as the bars, +disposed in about thirty longitudinal alternating rows. Peristome scarcely +constricted. The apical horn and the three parallel feet are of equal size +and similar form, straight, conical, one-sixth as long as the shell. + +_Dimensions._--Shell 0.12 long, 0.06 broad; horn and feet 0.02 long. + +_Habitat._--Fossil in Barbados. + + + +Subgenus 2. _Tripodocorys, Haeckel_, 1881, Prodromus, p. 428. + +_Definition._--Feet forked or branched. + + +8. _Tripilidium dichopodium_, n. sp. + +Shell hemispherical, nearly twice as broad as long, smooth. Pores +irregular, roundish, twice to four times as broad as the bars. Mouth wide +open. Apical horn spindle-shaped, half as long as the shell. Three feet +cylindrical, nearly straight and parallel, as long as the shell, forked at +the distal end. (Exhibits an external similarity to _Tripospyris semantis_, +Pl. 84, fig. 2, but has no trace of sagittal ring and constriction, and the +simple shell-cavity has a wide open mouth.) + +_Dimensions._--0.06 long, 0.1 broad; horn 0.03 long, feet 0.07 long. + +_Habitat._--North Pacific, Station 241, depth 2300 fathoms. + + +9. _Tripilidium cladopodium_, n. sp. + +Shell campanulate, rough, about as long as broad. Pores subregular, +circular, as broad as the bars. Mouth slightly constricted. Apical horn and +three divergent feet of nearly equal size and form, three-sided prismatic, +straight and stout, irregularly dentate and branched, somewhat longer than +the shell. + +_Dimensions._--Shell 0.08 diameter; horn and feet 0.1 to 0.12 long. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + + +{1143}Genus 502. _Tripodiscium_,[119] Haeckel, 1881, Prodromus, p. 428. + +_Definition._--#Archipilida# (vel Monocyrtida triradiata aperta) without +lateral ribs and apical horn, with three simple or branched terminal feet. + +The genus _Tripodiscium_ may be derived either from the preceding +_Tripilidium_ by loss of the apical horn, or from the nearly related +_Tristylospyris_ by loss of the sagittal ring and constriction. Some forms +of the latter genus can scarcely be distinguished from similar species of +the former. + + + +Subgenus 1. _Tripodiscinus_, Haeckel. + +_Definition._--Feet simple, not branched nor forked. + + +1. _Tripodiscium tristylospyris_, n. sp. + +Shell subspherical, with regular, circular pores, twice as broad as the +bars. Mouth constricted, half as broad as the shell, with three short +spindle-shaped feet, which are nearly parallel and vertical, half as long +as the shell. (Similar to _Tristylospyris scaphipes_, Pl. 84, fig. 13, but +without sagittal ring and constriction.) + +_Dimensions._--Shell 0.08 long, 0.07 broad; feet 0.04 long. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +2. _Tripodiscium ovatum_, n. sp. + +Shell ovate, rough, nearly as broad as long. Pores regular circular, +double-contoured, twice as broad as the bars. Mouth constricted, one-third +as broad as the shell, with three convergent short triangular feet. + +_Dimensions._--Shell 0.1 long, 0.09 broad; feet 0.02 long. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +3. _Tripodiscium clavatum_, n. sp. + +Shell ovate, smooth, one and a half times as long as broad. Pores irregular +roundish, of different sizes. Mouth constricted, two-thirds as broad as the +shell, with three divergent, straight club-shaped feet, nearly as long as +the shell. + +_Dimensions._--Shell 0.12 long, 0.08 broad; feet 0.1 long. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms. + + +{1144}4. _Tripodiscium campanula_, Haeckel. + + _Carpocanium campanula_, Stoehr, 1880, Palaeontogr., vol. xxvi. p. 96, + Taf. iii. fig. 9. + +Shell campanulate or subspherical, smooth, about as long as broad. Pores +small, regular circular, as broad as the bars. Mouth constricted, about +half as broad as the shell, with three short conical descending feet. + +_Dimensions._--Shell 0.06 long, 0.05 broad; feet 0.02 long. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms; fossil in +Sicily. + + + +Subgenus 2. _Tripodisculus_, Haeckel. + +_Definition._--Feet branched or forked. + + +5. _Tripodiscium furcatum_, n. sp. + +Shell ovate, rough, nearly as broad as long. Pores subregular, circular, +twice as broad as the bars. Mouth constricted, two-thirds as broad as the +shell, with three divergent parallel and vertical feet, which are as long +as the shell, and forked at the distal end. + +_Dimensions._--Shell 0.09 long, 0.08 broad; feet 0.07 long. + +_Habitat._--Tropical Atlantic, Station 338, depth 1990 fathoms. + + +6. _Tripodiscium ramosum_, n. sp. + +Shell ovate, tuberculate, nearly as broad as long. Pores irregular, +roundish, of very different sizes. Mouth constricted, half as broad as the +shell, with three large, divergent, irregularly branched feet, nearly twice +as long as the shell. (Similar to _Tristylospyris ramosa_, Pl. 52, fig. 23, +but without sagittal ring and constriction.) + +_Dimensions._--Shell 0.07 long, 0.06 broad; feet 0.15 long. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + +7. _Tripodiscium sphaerocephalum_, n. sp. (Pl. 52, fig. 21). + +Shell subspherical, rough, with circular pores of different sizes. Mouth +constricted, circular, simple, two-thirds as broad as the shell, with three +large divergent feet, which are three-sided prismatic, irregularly +branched, and twice as long as the shell. + +_Dimensions._--Shell 0.07 long, 0.08 broad; feet 0.12 long. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + + +{1145}Genus 503. _Tridictyopus_,[120] Haeckel, 1881, Prodromus, p. 428. + +_Definition._--#Archipilida# (vel Monocyrtida triradiata aperta) with three +latticed terminal feet. Shell ovate or subconical, with an apical horn. + +The genus _Tridictyopus_ differs from the nearly allied _Tripilidium_ in +the possession of three large fenestrated shovel-shaped feet, forming +direct prolongations of the large conical shell. The lattice work exhibits +a peculiar elegant structure recurring in the similar, perhaps nearly +related, _Cephalospyris_ (Pl. 83, fig. 10; Pl. 96, fig. 28). The central +capsule is large, ellipsoidal or ovate, and fills up the greater part of +the shell cavity (compare R. Hertwig, 1879, _loc. cit._, p. 75). + + +1. _Tridictyopus vatillum_, n. sp. (Pl. 51, fig. 8). + +Shell campanulate, about as long as broad (excluding horn and feet). Pores +irregular, polygonal, in the middle part more regular, triangular. Horn +short and stout, three-sided pyramidal. Three feet large, triangular, +shovel-shaped, about half as long as the shell. + +_Dimensions._--Shell 0.14 long, 0.15 broad. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +2. _Tridictyopus conulus_, n. sp. (Pl. 51, fig. 7). + +Shell campanulate conical, about one and a half times as long as broad +(excluding horn and feet). Pores mostly triangular, disposed in subregular +hexagonal figures, which are separated by bands of smaller irregular +polygonal pores. Horn short and stout, three-sided pyramidal. Three feet +triangular shovel-shaped, convergent, about one-sixth as long as the shell. + +_Dimensions._--Shell 0.3 long, 0.2 broad; horn 0.04 long, feet 0.05 long. + +_Habitat._--Equatorial Atlantic, Station 347, depth 2250 fathoms. + + +3. _Tridictyopus elegans_, R. Hertwig. + + _Tridictyopus elegans_, R. Hertwig, 1879, Organismus d. Radiol., p. 75, + Taf. vii. fig. 3, 3_a_, 3_b._ + +Shell slender, conical, campanulate, about twice as long as broad +(excluding horn and feet). Most pores subregular triangular, with some +irregular polygonal ones intermingled. The horn in the two observed +specimens was broken off, together with the conical apex of the shell. +Three feet triangular shovel-shaped, about one-sixth as long as the shell. + +_Dimensions._--Shell 0.3 long, 0.15 broad; feet 0.05 long. + +_Habitat._--Mediterranean (Messina), R. Hertwig, surface. + + + +{1146}Subfamily 2. ARCHIPERIDA, Haeckel, 1881, p. 429. + +_Definition._--#Tripocalpida# with the basal mouth of the shell fenestrated +(vel Monocyrtida triradiata clausa). + + + +Genus 504. _Euscenium_,[121] n. gen. + +_Definition._--#Archiperida# (vel Monocyrtida triradiata clausa) with a +free simple internal columella, prolonged into an apical horn. Three basal +feet free, without lateral wings. + +The genus _Euscenium_ and the three following nearly allied genera form +together the remarkable small group of Euscenida, probably one of the +oldest and most primitive of all #Cyrtoidea#, and perhaps the common root +of this suborder, arising directly from the #Plectoidea#. The simple +skeleton is composed of four radial beams united in one point (the cortinar +centrum). Three beams are directed downwards, and form three divergent +basal feet; the fourth beam is directed upwards and represents an apical +horn; its basal part is enclosed as "columella" in the cavity of the simple +shell, the lattice-work of which connects the four spines (compare above, +_Plectaniscus_, p. 924). In the genus _Euscenium_, the simplest of all, the +columella is simple, and the three feet also simple, without wings. + + + +Subgenus 1. _Euscenarium_, Haeckel. + +_Definition._--Three feet simple, not branched. + + +1. _Euscenium plectaniscus_ (Pl. 98, fig. 1). + +Shell three-sided pyramidal, thorny, about as long as broad, with three +dentate edges. Framework very loose, with irregular polygonal meshes; in +the middle of each of the three triangular sides a horizontal band of +denser network. Basal plate with three very large simple collar-holes. The +apical horn and the three feet are three-sided pyramidal, about half as +long as the columella, with three prominent irregularly dentate edges. The +horn is straight, whilst the three feet are hook-shaped, its distal end +being curved downwards and inwards. + +_Dimensions._--Shell 0.11 long, 0.13 broad. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + +2. _Euscenium archicyrtis_, n. sp. + +Shell three-sided pyramidal, smooth, nearly as long as broad, with three +straight edges connected by irregular loose framework with polygonal +meshes. Basal plate with three very large {1147}simple collar-holes. The +apical horn and the three feet are three-sided prismatic, smooth, about +twice as long as the columella, straight and widely divergent. + +_Dimensions._--Shell 0.08 long, 0.1 broad. + +_Habitat._--Tropical Pacific, Station 225, depth 4475 fathoms. + + +3. _Euscenium hemisphaericum_, n. sp. + +Shell hemispherical smooth, half as long as broad, with small and numerous +subregular circular pores. Basal plate with three large triangular simple +collar-holes. Horn slender, three-sided prismatic, twice as long as the +columella. Feet very slender, with three denticulate edges, widely +divergent and curved like the quadrant of a circle. + +_Dimensions._--Shell 0.04 long, 0.06 broad. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +4. _Euscenium tricolpium_, n. sp. (Pl. 53, fig. 12). + + _Archiscenium tricolpium_, Haeckel, 1881, Prodromus et Atlas, _loc. cit._ + +Shell cap-shaped, nearly hemispherical, with three vaulted hemispherical +bosoms between the three arches ascending from the feet to the horn. +Network very irregular, with polygonal meshes, of different form and size. +Basal plate with three large primary and some smaller irregular accessory +collar-holes. Horn slender, straight, twice as long as the columella. Feet +of the same length, slender, widely divergent, slightly curved. The three +edges of the horn and the feet are elegantly denticulated. + +_Dimensions._--Shell 0.04 long, 0.08 broad. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +5. _Euscenium tripospyris_, n. sp. (Pl. 84, fig. 8). + + _Tripospyris euscenium_, Haeckel, 1881, Prodromus et Atlas. + +Shell nearly spherical, smooth, with numerous small circular pores. Basal +plate also with numerous small pores. Horn and feet stout, three-sided +prismatic, straight or slightly curved, about as long as the thin, somewhat +curved columella. This species is closely allied to Tripospyris. + +_Dimensions._--Shell 0.11 to 0.12 diameter, horn and feet 0.08 to 0.1 long. + +_Habitat._--South Pacific, Station 298, depth 2225 fathoms. + + + +Subgenus 2. _Euscenidium_, Haeckel. + +_Definition._--Feet forked or branched. + + +6. _Euscenium furcatum_, n. sp. + +Shell campanulate, smooth, with numerous irregular roundish pores. Basal +plate with nine pores (three larger central and six smaller distal). Horn +club-shaped, half as long as the columella. {1148}Feet twice as long, +cylindrical, parallel, vertical, forked at the distal end. (Similar to +_Tripospyris semantis_, Pl. 84, fig. 2, but without sagittal feet.) + +_Dimensions._--Shell 0.07 long, 0.06 broad; horn 0.04 long, feet 0.1 long. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms. + + +7. _Euscenium quadratum_, n. sp. + +Shell campanulate, smooth with subregular square pores. Basal plate with +three large pores. Horn and feet of the same size and shape, twice as long +as the columella, three-sided prismatic, each with four or five verticils +of lateral branches. (Similar to the cephalis of _Clathrocorys murrayi_, +Pl. 64, fig. 8, but with four free spines without connecting +lattice-wings.) + +_Dimensions._--Shell 0.06 long, 0.05 broad; horn and feet 0.12 long. + +_Habitat._--Central Pacific, Station 272, surface. + + +8. _Euscenium ramosum_, n. sp. + +Shell subspherical, rough, with small subregular circular pores. Basal +plate with nine pores (three larger central and six smaller distal pores). +Horn and feet of the same size and form, three to four times as long as the +columella, three-sided prismatic, irregularly branched. + +_Dimensions._--Shell 0.06 diameter, horn and feet 0.15 to 0.2 long. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +Genus 505. _Cladoscenium_,[122] Haeckel, 1881, Prodromus, p. 429. + +_Definition._--#Archiperida# (vel Monocyrtida triradiata clausa) with a +free branched internal columella, prolonged into an apical horn. Three +basal feet free, without lateral wings. + +The genus _Cladoscenium_ differs from the preceding _Euscenium_ only in the +ramification of the internal columella, which bears one or more verticils +of three ascending lateral branches. The three branches of each verticil +lie in the same equidistant meridian planes as the three basal feet, and +are inserted with their distal ends on the inner surface of the simple +lattice-shell. The three feet are also branched, but without vertical +lattice-wings. _Cladoscenium_ is perhaps closely allied to _Clathrocorys_. + + +1. _Cladoscenium fulcratum_, n. sp. + +Shell subspherical, smooth, with large irregular roundish pores. Basal +plate with three large pores. Columella with a single verticil of three +ascending lateral branches. Apical horn as long as the {1149}columella, +simple, three-sided prismatic. Feet twice as long, widely divergent, +straight, prismatic, with some irregular basal branches. + +_Dimensions._--Shell 0.06 diameter, horn 0.05 long, feet 0.1 long. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +2. _Cladoscenium ancoratum_, n. sp. (Pl. 53, fig. 13). + +Shell campanulate, smooth, with irregular polygonal pores. Basal plate with +six pores (two large cardinal, two smaller jugular and two still smaller +cervical pores). Columella with a single verticil of three ascending +lateral branches (by mistake not distinct in the figure). Apical horn and +the three feet of the same form and size, slender, prismatic, twice to +three times as long as the shell, straight, in the distal half with three +slender recurved branches, anchor-shaped. + +_Dimensions._--Shell 0.05 long, 0.04 broad; horn and feet 0.1 to 0.15 long. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + +3. _Cladoscenium gladiatum_, n. sp. + +Shell subspherical, with irregular polygonal pores. Basal plate with three +large pores. Columella with two verticils of three ascending lateral +branches. Apical horn as long as the columella, three-sided prismatic. Feet +of the same form, twice as long, in the distal half with two opposite +transverse branches, sword-shaped. + +_Dimensions._--Shell 0.05 long, 0.06 broad; horn 0.04 long, feet 0.1 long. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +4. _Cladoscenium pinnatum_, n. sp. + +Shell campanulate, with irregular polygonal pores. Basal plate with four +pores (two major cardinal and two minor jugular). Columella with two +verticils of three ascending lateral branches, and prolonged into a slender +prismatic apical horn of twice the length, which bears four such verticils. +Feet twice as long as the horn, pinnate, each with four or five pairs of +opposite lateral branches, decreasing towards the thin distal end. + +_Dimensions._--Shell 0.06 long, 0.05 broad; horn 0.1 long, feet 0.2 long. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + +5. _Cladoscenium verticillatum_, n. sp. + +Shell campanulate, with subregular square pores. Basal plate with nine +pores (three larger central and six smaller distal). Columella with three +verticils of three ascending lateral branches. Apical horn and the three +basal feet of equal size and similar form, four to six times as long as the +columella, three-sided prismatic, each with four to five verticils of three +lateral branches, which are {1150}irregularly ramified and tapering towards +the distal end. (Similar to _Clathrocorys teuscheri_, Pl. 64, fig. 10, but +with four free spines, without connecting lattice-wings.) + +_Dimensions._--Shell 0.07 long, 0.06 broad; horn and feet 0.2 to 0.25 long. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +6. _Cladoscenium pectinatum_, n. sp. (Pl. 98, fig. 2). + +Shell subspherical, with irregular roundish pores. Basal plate with three +large holes. Columella with two verticils of three ascending lateral +branches. Apical horn and the three feet of nearly the same size and form, +three to four times as long as the columella, straight, three-sided +prismatic, each with five to eight verticils of three simple lateral +branches, tapering towards the distal end. + +_Dimensions._--Shell 0.07 long, 0.08 broad; horn and feet 0.16 to 0.22 +long. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + + +Genus 506. _Archiscenium_,[123] Haeckel, 1881, Prodromus, p. 429. + +_Definition._--#Archiperida# (vel Monocyrtida triradiata clausa) with a +free simple internal columella, prolonged into an apical horn. Three basal +feet connected with the horn by three vertical lateral wings. + +The genus _Archiscenium_ and the following nearly allied _Pteroscenium_ are +derived from the two preceding genera, from which they differ in the +development of three free vertical lateral lattice-wings; these arise from +the upper edge of the three basal feet and connect them with the three +edges of the apical horn. The basal part of the latter, enclosed in the +shell, forms an internal free columella, which in _Archiscenium_ is simple, +not branched. + + +1. _Archiscenium quadrispinum_, n. sp. (Pl. 53, fig. 11). + +Shell hemispherical, smooth, with a small number of large irregular +polygonal meshes and thin bars. Basal lattice with three very large central +meshes and six smaller peripheral meshes (two on the base of each foot). +Apical horn and the three feet of equal size and similar form, slender, +pyramidal, widely divergent, straight, as long as the shell-diameter. Three +lateral wings small, little prominent, each with two or three irregular +meshes. Central capsule subspherical. + +_Dimensions._--Shell 0.05 long, 0.1 broad. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + +2. _Archiscenium clathrocorys_, n. sp. + +Shell campanulate, smooth, with numerous irregular square meshes. Basal +lattice with three very large meshes. Apical horn and the three feet of +equal size and similar form, three-sided prismatic, {1151}widely divergent, +straight, twice as long as the shell-diameter. Three lateral wings broad, +each with a basal row of few very large irregular roundish meshes, and +several distal rows of small square meshes. This species is very similar to +_Clathrocorys murrayi_ (Pl. 64, fig. 8), but has no trace of thorax-wall. +The latter species may be derived from the former by development of the +thoracic lattice, which connects the three free feet. + +_Dimensions._--Shell 0.05 long, 0.06 broad. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +3. _Archiscenium tripterygium_, n. sp. + +Shell hemispherical, smooth, with numerous irregular roundish meshes of +very different sizes. Basal lattice with four large meshes, two major +cardinal and two minor cardinal pores. Apical horn and the three feet of +similar form and size, slender prismatic, three to four times as long as +the shell; the horn straight, the feet curved. Three lateral wings very +delicate, with a basal row of few large irregular polygonal meshes, and +several distal rows of similar small pores. + +_Dimensions._--Shell 0.04 long, 0.05 broad. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +4. _Archiscenium cyclopterum_, n. sp. (Pl. 98, fig. 3). + +Shell hemispherical, with small irregular roundish pores. Basal lattice +with four large meshes, two major cardinal and two minor jugular pores. +Apical horn and the three feet of similar form and size, slender prismatic, +straight, twice to four times as long as the shell. Three lateral wings +nearly semicircular, densely latticed, with the same pores as the shell, +and smooth convex margin. + +_Dimensions._--Shell 0.05 long, 0.06 broad. + +_Habitat._--South Pacific, Station 295, depth 1500 fathoms. + + +5. _Archiscenium callimitra_, n. sp. + +Shell campanulate, with irregular polygonal pores. Basal lattice with nine +meshes (three larger central and six smaller distal pores, as in +_Callimitra carolotae_, Pl. 63, fig. 8). Apical horn straight, prismatic, +slender, conical, twice as long as the shell. Feet longer and more slender, +slightly curved. Three lateral wings very broad, densely fenestrated, with +irregular polygonal pores of the same shape as in the similar _Callimitra +carolotae_ (Pl. 63, fig. 1). + +_Dimensions._--Shell 0.05 long, 0.04 broad. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + + +Genus 507. _Pteroscenium_,[124] Haeckel, 1881, Prodromus, p. 429. + +_Definition._--#Archiperida# (vel Monocyrtida triradiata clausa) with a +free branched internal columella, prolonged into an apical horn. Three +basal feet connected with the horn by three vertical lateral wings. + +{1152}The genus _Pteroscenium_ differs from the preceding _Archiscenium_ +only in the ramification of the internal columella, and therefore exhibits +to it the same relation that _Cladoscenium_ bears to _Euscenium_. The +branches of the columella form also here verticils of ascending branches, +three in each verticil, and their distal ends are inserted on the inner +surface of the lattice-shell. + + +1. _Pteroscenium arcuatum_, n. sp. (Pl. 98, fig. 4). + +Shell campanulate, smooth, nearly conical, somewhat broader than long, with +irregular dense network of small circular pores. Columella straight, with +two or three triradiate verticils of horizontal lateral branches, which are +inserted in the shell-wall. Horn slender pyramidal, as long as the shell. +Three divergent feet twice as long as the horn, strongly curved, thorny, +three-edged; the distance of their pointed ends twice as broad as the +shell. From the outer edge of each foot arise numerous ascending bristles, +which are connected together and with similar lateral branches of the horn +by curved arches, forming three delicate spiny vertical wings. + +_Dimensions._--Shell 0.06 long, 0.08 broad. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +2. _Pteroscenium arcadophorum_, n. sp. + +Shell campanulate, smooth, with irregular polygonal pores, very similar to +the preceding species but with much broader wings, forming several arcades +with three to five rows of irregular meshes. Columella with five or six +triradiate verticils of lateral branches. Horn twice as long as the shell, +of the same length as the strongly curved spinulate feet. + +_Dimensions._--Shell 0.09 long, 0.11 broad. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +3. _Pteroscenium pinnatum_, n. sp. (Pl. 53, figs. 14, 15, 16). + +Shell campanulate, smooth, somewhat longer than broad, with irregular +delicate network of small roundish pores. Columella straight, with numerous +(eight to twelve) triradiate verticils of ascending lateral branches, which +are inserted in the shell-wall. The uppermost end of the columella is a +conical apical horn. The three divergent feet are smooth, slender, conical, +slightly curved, about as long as the shell, pinnate, with six to ten pairs +of ascending lateral branches, parallel to those of the columella and +inserted on the three vaulted lateral wings. (Fig. 14 exhibits the outside +of the shell, fig. 15 the internal structure of the cortina, fig. 16 the +basal view.) + +_Dimensions._--Shell 0.1 long, 0.12 broad. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + +4. _Pteroscenium spinulosum_, n. sp. + +Shell campanulate, spinulate, about as long as broad, with small and +numerous irregular polygonal pores, very similar to the preceding species, +but differing in the more slender form of {1153}the horn and the feet, +bearing more numerous lateral branches (twelve to sixteen pairs on each +foot). Columella with six to eight triradiate verticils. Horn about as long +as the shell. + +_Dimensions._--Shell 0.1 long, 0.1 broad. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +5. _Pteroscenium macropodium_, n. sp. + +Shell campanulate, spinulate, with irregular polygonal pores; very similar +to the two preceding species, but differing in the size and shape of the +three feet, which are for the most part solid, triangular, nearly parallel, +vertical, very slender, three times as long as the shell, latticed only at +the curved base, with few pairs of lateral branches. Columella with four to +six triradiate verticils, as long as the stout triangular pyramidal horn. + +_Dimensions._--Shell 0.1 long, 0.08 broad. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +6. _Pteroscenium tripocolpum_, n. sp. + +Shell campanulate, spinulate, similar to _Euscenium tricolpium_ (Pl. 53, +fig. 12) with three vaulted hemispherical bosoms between the three delicate +arachnoidal vertical wings. Network loose, very irregular, with polygonal +meshes of very different sizes. Columella with three or four triradiate +verticils, as long as the slender pyramidal horn. Three feet twice as long, +somewhat curved, widely divergent, with three or four pairs of lateral +branches. The three edges of the feet and of the horn are elegantly +denticulated. + +_Dimensions._--Shell 0.06 long, 0.09 broad. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + + +Genus 508. _Peridium_,[125] Haeckel, 1881, p. 429. + +_Definition._--#Archiperida# (vel Monocyrtida triradiata clausa) without +internal columella, with an apical horn. + +The genus _Peridium_ (or _Archiperidium_, Prodromus, _loc. cit._) and the +two following nearly allied genera form together the small group of +Archibursida, differing from the four preceding genera (the Euscenida) in +the absence of an internal free columella. The three basal feet have +therefore no direct connection with the apical horn. _Peridium_, the +ancestral form of the Archibursida, may have originated either from +_Euscenium_ by reduction and loss of the columella, or directly from +_Tripospyris_ by loss of the sagittal ring and the longitudinal +constriction. + + + +Subgenus 1. _Peridarium_, Haeckel. + +_Definition._--Feet smooth, simple, neither spiny nor branched. + + +{1154}1. _Peridium lasanum_, n. sp. + +Shell subspherical, smooth, with subregular circular pores. Basal plate +with three large meshes. Horn apical, vertical, of the same size and form +as the three divergent smooth feet, slender pyramidal, twice to three times +as long as the shell. + +_Dimensions._--Shell-diameter 0.06 to 0.07, length of the three spines 0.15 +to 0.2. + +_Habitat._--North Pacific, Station 253, depth 3125 fathoms. + + +2. _Peridium papillatum_, n. sp. + +Shell subspherical, papillate, with subregular circular pores. Basal plate +with four meshes (two major cardinal and two minor jugular pores). Horn +occipital, oblique, three-sided pyramidal, half as long as the shell and as +the three widely divergent, subhorizontal, smooth feet. + +_Dimensions._--Shell diameter 0.07 to 0.08, length of the horn 0.04, of the +feet 0.08. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +3. _Peridium curvipes_, n. sp. + +Shell hemispherical, thorny, with irregular roundish pores. Basal plate +with six pores (two larger middle cardinal, two smaller anterior jugular +and two smaller posterior cervical pores, as in Pl. 53, figs. 13, 18). Horn +conical, oblique, arising from the middle of the occipital face, half as +long as the shell. Feet slender, conical, curved, smooth, twice as long as +the shell. + +_Dimensions._--Shell 0.04 long, 0.06 broad; horn 0.02 long; feet 0.08 long. + +_Habitat._--Tropical Pacific, Station 206, depth 2100 fathoms. + + + +Subgenus 2. _Archiperidium_, Haeckel. + +_Definition._--Feet spiny or branched. + + +4. _Peridium spinipes_, n. sp. (Pl. 53, fig. 9). + +Shell ovate, rough or thorny, with irregular roundish pores. Basal plate +with four pores (two larger cardinal and two smaller jugular pores). Horn +oblique, occipital, three-sided pyramidal, half as long as the shell, +connected with the caudal foot by a prominent crest. Three feet +horizontally expanded, prismatic, spiny, about as long as the shell. + +_Dimensions._--Shell 0.08 long, 0.06 broad; horn 0.04 long, feet 0.06 to +0.09 long. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +5. _Peridium palmipes_, n. sp. (Pl. 53, fig. 10). + +Shell ovate, smooth, with irregular roundish pores. Basal plate with three +large pores. Horn oblique, three-sided pyramidal, about as long as the +shell, inserted near its occipital base. Three feet prismatic, slender, +half as long, ending with a broad dentate plate. + +_Dimensions._--Shell 0.06 long, 0.05 broad; horn 0.05 long, feet 0.03 long. + +_Habitat._--Western Tropical Pacific, Station 224, depth 1850 fathoms. + + +{1155}6. _Peridium alatum_, n. sp. (Pl. 97, fig. 7). + +Shell subspherical smooth, with regular circular, hexagonally-framed pores. +Basal plate with nine pores (three larger central and six smaller distal +pores). Horn apical, of equal size and the same form as the three feet, +three-sided prismatic, with three broad prominent wings, somewhat longer +than the shell. + +_Dimensions._--Shell 0.07 long, 0.08 broad; horn and feet 0.1 to 0.12 long. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +7. _Peridium cervinum_, n. sp. + +Shell subspherical, spiny, with subregular circular pores. Basal plate with +four pores (?). Horn apical, conical, about as long as the shell. Feet +three to four times as long, cylindrical curved, with irregular simple or +forked branches like the antlers of a deer. + +_Dimensions._--Shell diameter 0.1, horn 0.1 long, feet 0.3 to 0.4 long. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + + +Genus 509. _Archipera_,[126] Haeckel, 1881, Prodromus, p. 429. + +_Definition._--#Archiperida# (vel Monocyrtida triradiata clausa) without +internal columella, with two or more apical horns. + +The genus _Archipera_ differs from the preceding _Peridium_ only in the +multiplication of the apical horn, which in the latter is always simple. +The number of horns is usually two or three, sometimes four or more. The +species bearing three horns may be derived directly from _Triceraspyris_ by +loss of the sagittal ring. + + +1. _Archipera cortiniscus_, n. sp. (Pl. 98, fig. 5). + +Shell ovate, thorny, with large roundish pores, which are closed by +sieve-plates with numerous small porules. Basal plate with two pairs of +simple large pores (two smaller jugular and two larger cardinal, similar to +Pl. 98, fig. 10_b_). Two horns divergent, curved, slender, pyramidal; the +apical horn longer than the shell, the frontal horn shorter. Three feet +divergent, longer than the shell, three-sided prismatic, at the distal end +club-shaped, thorny. + +_Dimensions._--Shell 0.1 long, 0.08 broad; horns and feet 0.11 to 0.14 +long. + +_Habitat._--Tropical Pacific, Station 225, depth 4475 fathoms. + + +2. _Archipera pentacantha_, n. sp. + +Shell pear-shaped, smooth, with numerous and small irregular roundish +pores. Basal plate with three larger pores. Two horns and three feet of +nearly equal size and similar form, three-sided {1156}prismatic, about as +long as the shell diameter, somewhat curved. The apical horn stands on the +apex, the frontal horn half-way up the shell. + +_Dimensions._--Shell 0.08 long, 0.06 broad; horns and feet 0.05 to 0.07 +long. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +3. _Archipera bicornis_, n. sp. + +Shell ovate, rough, with small regular circular, sparsely scattered pores. +Basal plate with four larger central and a peripheral coronal of twelve +smaller pores. Two horns near the apex widely divergent, somewhat shorter +than the shell, of equal size and similar form. Three feet twice as long, +horizontally expanded. All five spines slender, three-sided pyramidal, +straight. + +_Dimensions._--Shell 0.07 long, 0.06 broad; horns 0.05 long, feet 0.1 long. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +4. _Archipera tricornis_, n. sp. + +Shell subspherical, smooth, with subregular circular pores. Basal plate +with four large meshes (two major cardinal and two minor jugular pores). On +the apex three divergent pyramidal horns of different size, one larger +occipital and two smaller frontal horns. Three feet prismatic, about twice +as long as the shell. + +_Dimensions._--Shell diameter 0.05, length of the feet 0.1. + +_Habitat._--North Pacific, Station 253, depth 3125 fathoms. + + +5. _Archipera quadricornis_, n. sp. + +Shell ovate, smooth, with a small number of irregular roundish, widely +scattered pores. Basal plate with four crossed meshes of nearly equal size. +On the equator there arise four divergent prismatic horns of nearly equal +size, three of which correspond to the three feet, whilst the fourth is +opposite to the caudal foot. The three feet are also prismatic, as long as +the shell, horizontally expanded. (Similar to the upper half of +_Lithomelissa decacantha_, Pl. 56, fig. 2, but without thorax.) + +_Dimensions._--Shell 0.05 long, 0.04 broad; horns and feet 0.06 long. + +_Habitat._--South Pacific, Station 300, depth 1375 fathoms. + + +6. _Archipera multicornis_, n. sp. + +Shell hemispherical, spiny, with irregular polygonal pores. Basal plate +with six meshes (?). Between the smaller spines of the surface arise six +larger conical divergent horns. Three feet also conical, divergent, about +twice as long as the shell and the horns. + +_Dimensions._--Shell 0.05 long, 0.07 broad; horns 0.05 long, feet 0.1 long. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + + +{1157}Genus 510. _Archibursa_,[127] Haeckel, 1881, Prodromus, p. 429. + +_Definition._--#Archiperida# (vel Monocyrtida triradiata clausa) without +internal columella and without apical horn. + +The genus _Archibursa_ has probably arisen from _Peridium_ by loss of the +apical horn, and is the only genus of Archiperida which bears no horn. The +three basal feet are well-developed. It differs from the similar +_Tristylospyris_ by the absence of the sagittal ring and the corresponding +longitudinal constriction. + + +1. _Archibursa tripodiscus_, n. sp. (Pl. 98, fig. 6). + +Shell subspherical, smooth, with irregular roundish pores. Basal plate with +three large triangular pores of equal size (fig. 6). Three feet widely +divergent, straight, three-sided prismatic, about as long as the diameter +of the shell. + +_Dimensions._--Diameter of the shell 0.07, length of the feet 0.09. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + + +Family LX. #PHAENOCALPIDA#, n. fam. + + _Archiphormida_ et _Archiphaenida_, Haeckel, 1881, Prodromus, pp. 428, + 429. + +_Definition._--#Monocyrtida# multiradiata. (#Cyrtoidea# with a simple, not +jointed shell, resembling a simple cephalis, with numerous radial apophyses +(four to nine or more). + +The family #Phaenocalpida#, composed of the Archiphormida and Archiphaenida +of my Prodromus, comprises those #Cyrtoidea# in which the lattice-shell is +quite without transverse constriction, but bears numerous radial apophyses. +The two subfamilies differ in the shape of the basal mouth, which in the +Archiphormida is a simple wide opening, but is closed in the Archiphaenida +by a lattice-plate. + +Several Phaenocalpida were formerly described by Ehrenberg, viz., +_Halicalyptra virginica_ (in 1844) and _Litharachnium arachnodiscus_ (in +1872, called by him _Carpocanium_, though it is quite different from this +genus, and closely allied to my _Litharachnium tentorium_, figured in +1862). These forms belong to the Archiphormida (with open mouth). Several +fossil Archiphaenida (with closed mouth) were figured by Ehrenberg, in +1875, as belonging to _Petalospyris_ (_ocellata_, _carinata_, _flabellum_), +though the absence of the sagittal ring and the corresponding longitudinal +constriction demonstrates their character as _Phaenocalpis_. + +{1158}The Phaenocalpida are probably an artificial family, composed of +three or four (or perhaps more) different groups, which have a quite +different origin. The Litharachnida (genera 511-515) and the Haliphormida +(genera 516-518) are probably derived from the Sethophormida by loss of the +cephalis, the retrograde metamorphosis of which may be observed in all its +different stages. The Halicalyptrida (genera 519-521) are perhaps +independent of the other Phaenocalpida, and may be Archicorida which have +produced a corona of teeth around the mouth, without relation to lost +radial ribs. The Phaenoscenida (_Phaenocalpis_, _Phaenoscenium_) may be +derived from the Euscenida (genera 504-507) by interpolation of interradial +feet between the three primary ones, or directly from the #Plectoidea#. The +Calpophaenida, on the other hand (_Calpophaena_, _Archiphaena_), may have +arisen from the Zygospyrida (_Petalospyris_, _Gorgospyris_) by loss of the +sagittal ring and the longitudinal constriction. The phylogeny of the +Phaenocalpida is therefore a very complicated problem, as yet unsolved. + +_Synopsis of the Genera of Phaenocalpida._ + + ------------------------------------------------------------------------- + I. Subfamily Archiphormida. + Basal mouth of the shell a simple wide opening. + -------------------- + Radial ribs enclosed in the wall of the shell, usually prolonged into + free terminal feet. + ------------------------------------------------------------------------- + { Shell simple, with simple + { network, 511. _Bathropyramis_. + Shell slender, { + pyramidal { Shell simple, with double + (without horn). { network, 512. _Cinclopyramis_. + { + { Shell double, with an outer + { mantle, 513. _Peripyramis_. + + Shell flatly } Radial ribs simple, 514. _Litharachnium_. + campanulate or } + discoidal (without } Radial ribs branched, 515. _Cladarachnium_. + horn). } + + { Mouth smooth, constricted + Shell ovate, { (no horn), 516. _Cystophormis_. + urceolate or { + campanulate. { Mouth, with { With horn, 517. _Haliphormis_. + { a corona of { + { feet. { No horn, 518. _Archiphormis_. + ------------------------------------------------------------------------- + No radial ribs in the wall of the shell. Mouth surrounded by a corona of + free terminal feet. + ------------------------------------------------------------------------- + { With horn, 519. _Halicalyptra_. + Shell simple without mantle. { + { No horn, 520. _Carpocanistrum_. + + Shell double, with an external mantle (no horn), 521. _Arachnocalpis_. + ------------------------------------------------------------------------- + II. Subfamily Archiphaenida. Basal mouth closed by a lattice-plate. + -------------------- + In the axis of the shell-cavity a free columella. + ------------------------------------------------------------------------- + In the axis of the { Columella simple, 522. _Phaenocalpis_. + shell-cavity a { + free columella. { Columella branched, 523. _Phaenoscenium_. + ------------------------------------------------------------------------- + Shell-cavity simple, without axial columella. + ------------------------------------------------------------------------- + Shell-cavity simple, { Apex with a horn, 524. _Calpophaena_. + without axial { + columella. { No apical horn, 525. _Archiphaena_. + + + +{1159}Subfamily 1. ARCHIPHORMIDA, Haeckel, 1881, Prodromus, p. 428. + +_Definition._--#Phaenocalpida# with the basal mouth of the shell open (vel +Monocyrtida multiradiata aperta). + + + +Genus 511. _Bathropyramis_,[128] Haeckel, 1881, Prodromus, p. 428. + +_Definition._--#Archiphormida# (vel Monocyrtida multiradiata aperta) with +simple, slender pyramidal shell and numerous radial beams (six to nine or +more). Network simple, with large, unfenestrated, quadrangular meshes. + +The genus _Bathropyramis_ and the following four nearly allied genera form +together a peculiar group of Archiphormida, the Litharachnida, possessing +near relations to _Sethopyramis_ and the allied Sethophormida, from which +they are probably derived by reduction and loss of the small cephalis. The +shell in all these forms is distinctly pyramidal, composed of numerous +divergent radial beams (commonly six to nine), which form the edges of the +pyramid, and are connected by parallel horizontal rings. The quadrangular +meshes so produced are quite simple in _Bathropyramis_. This genus cannot +be sharply separated from _Sethopyramis_, its ancestral form. + + + +Subgenus 1. _Acropyramis_, Haeckel, 1881, Prodromus, p. 428. + +_Definition_.--Shell smooth, without spines on the surface. + + +1. _Bathropyramis acephala_, n. sp. + +Shell smooth, slenderly pyramidal, with three cortinar pores at the apex +and with six stout radial beams or longitudinal ribs, connected by twelve +to sixteen complete hexagonal horizontal rings. Meshes nearly square, +increasing gradually in size towards the mouth. + +_Dimensions._--Shell 0.25 long, 0.15 broad. + +_Habitat._--South Pacific, Station 295, depth 1500 fathoms. + + +2. _Bathropyramis quadrata_, n. sp. (Pl. 54, fig. 1). + +Shell smooth, slenderly pyramidal, with three cortinar pores at the apex +and nine stout radial beams, connected by eight to twelve complete circular +horizontal rings. Meshes subregular, square, increasing in size gradually +towards the circular mouth. + +_Dimensions._--Shell 0.2 to 0.3 long, 0.12 to 0.2 broad. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +{1160}3. _Bathropyramis trapezoides_, n. sp. (Pl. 54, fig. 3). + +Shell smooth, broadly pyramidal, with four cortinar pores at the apex and +eight (or sometimes nine) stout radial beams, connected by twelve to +sixteen complete octagonal horizontal rings. Meshes trapezoidal, of nearly +equal length, but gradually increasing in breadth. + +_Dimensions._--Shell 0.3 long, 0.3 broad. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +4. _Bathropyramis interrupta_, n. sp. (Pl. 55, fig. 7). + +Shell smooth, flatly pyramidal, nearly discoidal, with four cortinar pores +at the apex and nine to ten stout radial beams, connected by eight to +sixteen interrupted rings; the rings are complete only in the apical part, +in the distal part more or less irregularly interrupted. + +_Dimensions._--Shell 0.12 long, 0.36 broad. + +_Habitat._--North Atlantic, Station 354, surface. + + +5. _Bathropyramis medusa_, n. sp. + +Shell smooth, flatly pyramidal, nearly discoidal, with four cortinar pores +and numerous radial beams (thirty to fifty); the four perradial of these +are prolongations of the four cortinar beams, and alternate with four +interradial of the same size. Between these are intercalated eight adradial +beams arising from the third ring; and between the former and the latter, +sixteen to twenty-four peripheral radial beams, arising from the fourth to +the sixth ring. The inner four to six rings are complete, the outer ten to +fifteen irregularly interrupted. + +_Dimensions._--Shell 0.08 long, 0.3 to 0.4 broad. + +_Habitat._--South Atlantic, Station 338, surface. + + + +Subgenus 2. _Cladopyramis_, Haeckel, 1881, Prodromus, p. 428. + +_Definition_.--Shell spiny, with prominent simple or branched spines on the +surface. + + +6. _Bathropyramis spinosa_, n. sp. + +Shell spiny, slenderly pyramidal, with three cortinar pores at the apex and +with nine strong radial beams, connected by fifteen to twenty complete +parallel rings. Meshes subregular square, increasing gradually in size. +Surface covered with simple, strong conical spines, arising from the nodal +points. + +_Dimensions._--Shell 0.24 long, 0.16 broad. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +{1161}7. _Bathropyramis ramosa_, n. sp. (Pl. 54, fig. 4). + +Shell spiny, slenderly pyramidal, with three cortinar pores at the apex, +and with nine (or sometimes eight or ten) strong radial beams, connected by +fifteen to eighteen complete parallel rings. Meshes subregular, square, +increasing gradually in size. Surface covered with forked or irregularly +branched spines, arising from the nodal points. + +_Dimensions._--Shell 0.3 long, 0.17 broad. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + + +Genus 512. _Cinclopyramis_,[129] Haeckel, 1881, Prodromus, p. 428. + +_Definition._--#Archiphormida# (vel Monocyrtida multiradiata aperta) with +simple, slender, pyramidal shell, and numerous radial beams (six to nine or +more). Network double, with a delicate arachnoidal fenestration, filling up +the large quadrangular meshes. + +The genus _Cinclopyramis_ differs from the preceding _Bathropyramis_ in the +development of a very delicate secondary network, filling up the large +quadrangular meshes, which are produced by the crossing of the radial beams +and the parallel horizontal rings. It therefore bears the same relation to +the preceding genus that _Plectopyramis_ does to _Sethopyramis_; it is +perhaps derived directly from the former by loss of the small cephalis. + + +1. _Cinclopyramis cribellum_, n. sp. + + _Cinclopyramis cribellum_ = "Ladder of lattice-shape," Bury, 1862, + Polycystins of Barbados, pl. xii. fig. 6. + +Shell slender, pyramidal, with six strong radial ribs, which are connected +by twelve to sixteen complete horizontal rings. Meshes trapezoidal, filled +up by a very delicate and regular secondary network with square porules +(two to four horizontal threads in each larger mesh). + +_Dimensions._--Shell 0.2 to 0.3 long, 0.12 to 0.16 broad. + +_Habitat._--Fossil in Barbados. + + +2. _Cinclopyramis infundibulum_, n. sp. (Pl. 54, fig. 7). + +Shell slender, pyramidal, with nine strong radial ribs, which are connected +by eighteen to twenty-four complete horizontal rings. Meshes subregular +square, filled up by a very delicate and regular secondary network with +square porules (ten to twelve horizontal threads in each larger mesh). Apex +of the pyramid with three very small cortinar pores. + +_Dimensions._--Shell 0.3 to 0.4 long, 0.2 to 0.25 broad. + +_Habitat._--Tropical Atlantic, Station 338, depth 1990 fathoms. + + +{1162}3. _Cinclopyramis lithosestrum_, n. sp. + +Shell slender, pyramidal, with twelve strong radial ribs (six primary +longer and six secondary shorter) connected by twelve to fifteen +interrupted irregular rings. Meshes irregular square or trapezoidal, filled +up by a delicate secondary network with irregular polygonal porules. + +_Dimensions._--Shell 0.4 to 0.5 long, 0.2 to 0.3 broad. + +_Habitat._--Fossil in Barbados. + + + +Genus 513. _Peripyramis_,[130] Haeckel, 1881, Prodromus, p. 428. + +_Definition._--#Archiphormida# (vel Monocyrtida multiradiata aperta) with +double, slenderly pyramidal shell, and numerous radial beams (six to nine +or more). Network double, with an external arachnoidal or spongy envelope +around the primary lattice-shell. + +The genus _Peripyramis_ differs from its probable ancestral form, +_Bathropyramis_, by development of a delicate external envelope around the +primary shell, and therefore bears to it the same relation that +_Spongopyramis_ among the Dicyrtida does to _Sethopyramis_. It may also be +derived directly from the former by loss of the cephalis. + + +1. _Peripyramis circumtexta_, n. sp. (Pl. 54, fig. 5). + +Shell slender, pyramidal, with nine strong radial beams, connected by +fifteen to twenty transverse horizontal rings, which are partly complete, +partly interrupted. Meshes subregular, square. From the nodal points of the +surface there arise branched spines, which at equal distances from it are +connected by thin threads, forming a delicate outer arachnoidal shell with +large irregular polygonal meshes. + +_Dimensions._--Shell 0.32 long, 0.16 broad. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +2. _Peripyramis spongiosa_, n. sp. + +Shell slender, pyramidal, with nine strong radial beams, connected by +twelve to eighteen irregular interrupted rings. Meshes irregular, square or +polygonal. From the whole surface arise numerous branched spines, which by +communication and dense ramification form an outer spongy envelope around +the shell. (Similar to _Spongopyramis spongiosa_, Pl. 56, fig. 10.) + +_Dimensions._--Shell 0.45 long, 0.32 broad. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + + +{1163}Genus 514. _Litharachnium_,[131] Haeckel, 1860, Monatsber. d. k. +preuss. Akad. d. Wiss. Berlin, p. 835. + +_Definition._--#Archiphormida# (vel Monocyrtida multiradiata aperta) with +flatly conical, tent-shaped or nearly discoidal shell, and numerous, +simple, radial beams in its wall. + +The genus _Litharachnium_, and the closely allied genus _Cladarachnium_, +differ from the preceding similar genera mainly in the flat form of the +depressed shell, which is not slenderly pyramidal, but more tent-shaped or +nearly discoidal. The radial ribs are generally not straight, but more or +less curved. The top of the tent exhibits three or four important meshes, +the original pores of the cortinar septum. _Litharachnium_ may be derived +directly from _Sethophormis_ by reduction and loss of the cephalis. + + + +Subgenus 1. _Litharachnidium_, Haeckel. + +_Definition._--Apex with three cortinar pores (one odd sternal and two +paired cardinal pores). + + +1. _Litharachnium tentorium_, Haeckel. + + Litharachnium tentorium, Haeckel, 1862, Monogr. d. Radiol., p. 281, Taf. + iv. figs. 7-10. + +Shell flatly conical or tent-shaped, with concave lateral outlines. Apex +with three equal cortinar pores. Twenty radial ribs at nearly equal +distances. Between them very numerous and thin secondary ribs, crossed by +more than one hundred concentric rings. Pores square, as in all the +following species. Margin truncate, circular. + +_Dimensions._--Shell 0.35 long, 0.8 broad. + +_Habitat._--Mediterranean (Messina). + + +2. _Litharachnium araneosum_ (Pl. 55, figs. 8, 10). + +Shell flatly conical, nearly discoidal, with straight lateral outlines. +Apex with three unequal cortinar pores (one odd smaller sternal and two +paired larger cardinal pores). Twenty radial ribs at unequal distances, +with numerous intercalated secondary ribs. Margin ciliate. + +_Dimensions._--Shell 0.18 long, 0.32 broad. + +_Habitat._--Central Pacific, Station 271, surface. + + +{1164}3. _Litharachnium arachnodiscus_, Haeckel. + + _Litharachnium arachnodiscus_, Haeckel, 1862, Monogr. d. Radiol., p. 283. + + _Carpocanium arachnodiscus_, Ehrenberg, 1861, Monatsber. d. k. preuss. + Akad. d. Wiss. Berlin, p. 296; Abhandl. d. k. Akad. d. Wiss. Berlin, + 1872, Taf. ii. fig. 8. + +Shell flatly campanulate, nearly discoidal, with convex (?) lateral +outlines. Apex with three unequal cortinal pores. Nine stronger radial +primary ribs complete; between them numerous secondary intercalated ribs +(sixty to seventy). Margin ciliate. + +_Dimensions._--Shell 0.03 long, 0.1 broad (?). + +_Habitat._--Arctic Ocean (between Greenland and Iceland), depth 1000 +fathoms (Schaffner). + + +4. _Litharachnium epeira_, n. sp. (Pl. 55, fig. 9). + +Shell flatly conical or tent-shaped, with concave lateral outlines. Apex +with three unequal cortinar pores. Twelve stronger radial primary ribs +complete; between them numerous (twenty-four to thirty-six) thinner +secondary, and very numerous (more than one hundred) tertiary ribs. Margin +reflexed, like the curved brim of a hat. + +_Dimensions._--Shell 0.12 long, 0.27 broad. + +_Habitat._--Central Pacific, Station 274, surface. + + + +Subgenus 2. _Litharachnoma_, Haeckel. + +_Definition._--Apex with four cortinar pores (two anterior jugular and two +posterior cardinal pores). + + +5. _Litharachnium discoides_, n. sp. + +Shell flat, funnel-shaped, nearly discoidal, with concave outlines. Apex +with four unequal cortinar pores (two smaller jugular and two larger +cardinal pores). Twelve strong primary or perradial ribs alternating with +twelve weaker secondary or interradial ribs; between these there are +twenty-four shorter tertiary or adradial ribs, and in the outer flat, +discoidal, half of the shell very numerous peripheral radial ribs (more +than two hundred to three hundred). Margin flat, discoidal. + +_Dimensions._--Shell about 0.2 long, 1.12 broad. + +_Habitat._--Equatorial Atlantic, Station 347, surface. + + +6. _Litharachnium pilidium_, n. sp. + +Shell flat, hat-shaped, with S-shaped outlines, in the upper half convex, +in the lower half concave. Apex with four equal crossed cortinar pores. +Thirty primary ribs of equal size; four of them are the prolongations of +the four cortinar beams, eight intercalate between these secondary, +{1165}and the other eighteen tertiary. Between them very numerous +peripheral beams. Margin broad horizontal, reflexed like the brim of a +"Bismarck" hat. + +_Dimensions._--Shell 0.17 long, 0.38 broad. + +_Habitat._--South Pacific, Station 298, depth 2225 fathoms. + + + +Genus 515. _Cladarachnium_,[132] Haeckel, 1881, Prodromus, p. 430. + +_Definition._--#Archiphormida# (vel Monocyrtida multiradiata aperta) with +flatly conical, tent-shaped or nearly discoidal shell, and numerous +branched radial beams. + +The genus _Cladarachnium_ differs from the preceding _Litharachnium_ only +in the ramification of the radial beams, the distal ends of which project +over the margin of the shell. Only one species of the genus has been +observed. + + +1. _Cladarachnium ramosum_, n. sp. (Pl. 55, figs. 5, 6). + +Shell flatly conical or tent-shaped, with nearly straight lateral outlines; +apical part somewhat higher. Apex with three cortinar pores surrounded by a +few girdles of larger pores. From these there arise about twelve to fifteen +strong radial beams at unequal distances; these are somewhat curved and +irregularly branched. The network between them has irregular polygonal +meshes and is more delicate towards the periphery. Margin with twenty-four +to thirty irregular indentations or concave excisions, separated by the +prominent distal ends of the branched ribs. + +_Dimensions._--Shell 0.16 long, 0.4 broad. + +_Habitat._--Central Pacific, Station 271, surface. + + + +Genus 516. _Cystophormis_,[133] n. gen. + +_Definition._--#Archiphormida# (vel Monocyrtida multiradiata aperta) with +ovate or urceolate shell and numerous radial ribs in its wall. Mouth more +or less constricted, smooth, truncated. Apex without horn. + +The genus _Cystophormis_, like the preceding genera, exhibits numerous +prominent radial or longitudinal ribs in the wall of the urceolate shell; +it differs from these in the constricted and truncated mouth, with smooth +margin of the peristome. + + +1. _Cystophormis pila_, n. sp. (Pl. 52, fig. 1). + +Shell balloon-shaped, subspherical, with twenty denticulate meridional +ribs, alternating with twenty longitudinal rows of circular pores, which +are twice as broad as the bars. Peristome constricted and then dilated, +smooth, half as broad as the shell. + +_Dimensions._--Shell 0.11 long, 0.09 broad; mouth 0.06 broad. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +{1166}2. _Cystophormis aerostatica_, n. sp. (Pl. 52, figs. 2, 3). + +Shell balloon-shaped, subspherical, with twenty smooth meridional ribs, +alternating with twenty longitudinal rows of circular pores, of the same +breadth as the bars. Peristome constricted, about half as broad as the +shell. + +_Dimensions._--Shell 0.09 long, 0.07 broad; mouth 0.03 broad. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +3. _Cystophormis spiralis_, n. sp. (Pl. 51, fig. 9). + +Shell ovate, one and a half times as long as broad, with twenty spirally +convoluted, elegantly denticulated ribs, alternating with twenty spiral +rows of small circular pores, of about the same breadth as the bars. +Peristome constricted, very small, only one-seventh as broad as the shell. + +_Dimensions._--Shell 0.1 long, 0.07 broad; mouth 0.01 broad. + +_Habitat._--West Tropical Pacific, Station 225, depth 4475 fathoms. + + +4. _Cystophormis tabulata_ (Pl. 79, fig. 2). + +Shell urceolate and tabulate, twice as long as broad with twenty-five to +thirty denticulated longitudinal ribs crossed by twenty to twenty-four +transverse rings. Pores therefore regularly disposed in longitudinal and +transverse rows; each pore circular, with a square frame. Peristome +constricted, scarcely half as broad as the shell. + +_Dimensions._--Shell 0.2 long, 0.1 broad; mouth 0.04 broad. + +_Habitat._--South Pacific, Station 300, depth 1375 fathoms + + + +Genus 517. _Haliphormis_,[134] Ehrenberg, 1847, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 54 (_sensu mutato_). + +_Definition._--#Archiphormida# (vel Monocyrtida multiradiata aperta) with +numerous radial ribs in the wall of the campanulate shell, prolonged into +free terminal feet. Apex with a horn. + +The genus _Haliphormis_ (with an apical horn) and the following +_Archiphormis_ (without a horn) comprise those Archiphormida in which the +open mouth is more or less constricted and surrounded by a coronet of +radial feet, as terminal prolongations of the radial ribs of its wall. The +few forms, upon which Ehrenberg originally founded the genus _Haliphormis_, +are partly not recognisable, partly belong to other genera. We therefore +give here a new definition of the genus, as stated in my Prodromus, 1881, +p. 428. + + +{1167}1. _Haliphormis lagena_, n. sp. (Pl. 97, fig. 5) + +Shell bottle-shaped, twice as long as broad, tapering towards both ends, +with nine longitudinal curved ribs. These are connected by irregular +transverse beams, and the quadrangular meshes, so produced, are filled up +by irregular, delicate, arachnoidal framework. The constricted mouth is +half as broad as the middle part of the shell and surrounded by nine +slender convergent feet, the free distal ends of the ribs. The apex bears a +small knob with an oblique horn, perhaps the rudimentary cephalis of +_Sethamphora_ or _Sethopyramis_ (?). + +_Dimensions._--Shell 0.6 to 0.7 long, 0.3 to 0.4 broad. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +2. _Haliphormis costata_, n. sp. + +Shell campanulate, somewhat longer than broad, with twelve prominent +longitudinal ribs, alternating with twelve rows of regular circular pores. +Mouth constricted half as broad as the shell, with twelve long triangular +feet, formed by the free distal ends of the ribs. Apical horn short and +stout, triangular pyramidal. + +_Dimensions._--Shell 0.12 long, 0.1 broad; mouth 0.07 long. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +Genus 518. _Archiphormis_,[135] Haeckel, 1881, Prodromus, p. 428. + +_Definition._--#Archiphormida# (vel Monocyrtida multiradiata aperta) with +numerous radial ribs in the wall of the campanulate or urceolate shell, +prolonged into free terminal feet. Apex without horn. + +The genus _Archiphormis_ differs from the preceding _Haliphormis_, its +probable ancestral form, in the absence of the apical horn. The number of +the longitudinal ribs, which are prolonged into terminal feet, is from six +to nine or twelve or even more. + + +1. _Archiphormis cancellata_, Haeckel. + + (?) _Halicalyptra cancellata_, Ehrenberg, 1854, Monatsber. d. k. preuss. + Akad. d. Wiss. Berlin, p. 243. + +Shell cup-shaped or campanulate, with six prominent ribs, prolonged into +six terminal triangular feet, one-third as long as the shell. Ribs +connected by five or six transverse horizontal rings; meshes between them +rounded squarish. (As Ehrenberg has given no figure of this species, its +identity with the Challenger specimen is doubtful.) + +_Dimensions._--Shell 0.08 long, 0.06 broad; mouth 0.04 broad. + +_Habitat._--North Atlantic, Station 353, depth 2965 fathoms. + + +{1168}2. _Archiphormis campanulata_, n. sp. + +Shell campanulate, with nine prominent denticulate ribs, prolonged into +nine terminal feet, which are broad, lamellar, truncate, nearly vertical, +one-third as long as the shell. Pores between the ribs circular, disposed +in nine longitudinal and seven to eight transverse rows. + +_Dimensions._--Shell 0.09 long, 0.1 broad; mouth 0.06 broad. + +_Habitat._--Central Pacific, Station 270, depth 2925 fathoms. + + +3. _Archiphormis urceolata_, n. sp. (Pl. 98, fig. 11). + +Shell urceolate, with nine smooth prominent curved ribs, prolonged into +nine triangular convergent short feet, scarcely one-sixth as long as the +shell. Pores between the ribs in nine regular longitudinal rows, twice or +three times as broad as long, quadrangular, eight to twelve pores in each +row. Mouth constricted, half as broad as the shell. + +_Dimensions._--Shell 0.13 long, 0.11 broad; mouth 0.06 broad. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + + +Genus 519. _Halicalyptra_,[136] Ehrenberg, 1847, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 54 (_sensu emendato_). + +_Definition._--#Archiphormida# (vel Monocyrtida multiradiata aperta) +without radial ribs in the wall of the campanulate or ovate shell. Mouth +with a coronet of radial feet. Apex with a horn. + +The genus _Halicalyptra_ and the two following closely allied genera differ +from the preceding Archiphormida in the absence of radial ribs. The +multiradiate structure is indicated only by the terminal spines or feet, +forming a coronet around the mouth. These feet are either the free ends of +reduced ribs, or new productions of the peristome. _Halicalyptra_ may be +derived from _Calpophaena_ and _Petalospyris_ by loss of the basal +lattice-plate of the cephalis. But it is also possible that it has been +derived from _Anthocyrtis_ by loss of the cephalis, and that its shell +corresponds to the thorax of the latter. + + + +Subgenus 1. _Acrocalpis_, Haeckel, 1881, Prodromus, p. 427. + +_Definition._--Shell smooth, without spines or thorns (other than the feet +and the apical horn). + + +{1169}1. _Halicalyptra virginica_, Ehrenberg. + + _Halicalyptra virginica_, Ehrenberg, 1854, Mikrogeol., Taf. xviii. fig. + 110. + + _Halicalyptra virginica_, Haeckel, 1862, Monogr. d. Radiol., p. 289. + + _Haliomma virginicum_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 71. + + _Acrocalpis virginica_, Haeckel, 1881, Prodromus, p. 427. + +Shell smooth, campanulate, nearly hemispherical. Pores subregular circular, +about as broad as the bars. Horn conical, half as long as the shell. +Peristome scarcely constricted, with six conical divergent feet, as long as +the horn. + +_Dimensions._--Shell diameter 0.04 to 0.05, length of the feet 0.02. + +_Habitat._--Fossil in tertiary rocks of Barbados and North America +(Richmond, Virginia). + + +2. _Halicalyptra campanula_, n. sp. + + _Podocyrtis spinosa_, Bury, 1862, Polycystins of Barbados, pl. xvii. fig. + 3. + +Shell smooth, campanulate. Pores irregular, roundish, about as broad as the +bars. Horn large conical, about as long as the shell. Peristome not +constricted, with six large divergent feet, which are as long as the shell, +lamellar, with dentate edges. + +_Dimensions._--Shell diameter 0.07, length of the feet 0.07. + +_Habitat._--Fossil in Barbados. + + +3. _Halicalyptra ampulla_, n. sp. + + _Petalospyris foveolata_, var., Bury, 1862, Polycystins of Barbados, pl. + ix. fig. 1. + +Shell smooth, subspherical, inflate. Pores regular, circular, twice as +broad as the bars. Horn slender conical, about as long as the shell. +Peristome constricted, with six divergent cylindrical, irregularly curved +feet, twice to three times as long as the shell. + +_Dimensions._--Shell diameter 0.12, feet 0.2 to 0.3 long. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms; also fossil +in Barbados. + + +4. _Halicalyptra novena_, n. sp. + +Shell smooth, campanulate. Pores irregular, roundish. Horn slender conical, +about as long as the shell. Peristome slightly constricted, with nine +slender divergent feet of the same length. (Very similar to _Petalospyris +foveolata_, Ehrenberg, but without internal columella and ring, with +perfectly simple shell-cavity and open mouth.) + +_Dimensions._--Shell 0.09 diameter, feet 0.1 long. + +_Habitat._--Fossil in Barbados. + + +5. _Halicalyptra petalospyris_, n. sp. (Pl. 98, fig. 12). + +Shell smooth, campanulate. Pores small, circular, irregularly scattered. +Horn stout, pyramidal, about as long as the shell. Peristome scarcely +constricted, with fifteen to twenty broad {1170}lamellar or lanceolate +feet, which are twice to three times as long as the shell, parallel and +vertical. (Very similar to _Petalospyris flabellum_, &c., Ehrenberg, 1875, +_loc. cit._, Taf. xxii. figs. 6-8, but without any trace of sagittal ring +or columella.) + +_Dimensions._--Shell 0.05 to 0.08 diameter, feet 0.15 to 0.25 long. + +_Habitat._--Central Pacific, Stations 266 to 268, depth 2700 to 2900 +fathoms. + + + +Subgenus 2. _Echinocalpis_, Haeckel, 1881, Prodromus, p. 427. + +_Definition._--Shell spiny, covered with numerous spines or thorns (besides +the feet and the apical horn). + + +6. _Halicalyptra spinosa_, n. sp. + +Shell spiny, ovate, inflate in the apical half. Pores irregular polygonal, +four to eight times as broad as the bars. Peristome constricted, half as +broad as the shell, with nine slender divergent feet, which like the apical +horn are curved, twice to three times as long as the shell and five to ten +times as long as the numerous bristles of the surface. + +_Dimensions._--Shell 0.08 long, 0.06 broad; feet 0.15 to 0.25 long. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +7. _Halicalyptra castanella_, n. sp. + +Shell spiny, nearly spherical. Pores irregular roundish. Peristome +constricted, scarcely one-third as broad as the shell, with twelve to +twenty slender, widely divergent feet, which like the horn are irregularly +curved, and longer than the shell. (Very similar to certain forms of the +Phaeodarium _Castanella_, Pl. 113, fig. 2.) + +_Dimensions._--Shell 0.13 diameter, feet 0.15 to 0.18 long. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + + +Genus 520. _Carpocanistrum_,[137] n. gen. + +_Definition._--#Archiphormida# (vel Monocyrtida multiradiata aperta) +without radial ribs in the wall of the campanulate or ovate shell. Mouth +with a corona of radial feet. Apex without horn. + +The genus _Carpocanistrum_ differs from the similar preceding +_Halicalyptra_ in the loss of the apical horn. It is very nearly related to +the Dicyrtid _Carpocanium_ and may be easily confounded with it. But in the +latter the uppermost part of the shell-cavity includes a rudimentary +cephalis with a cortinar septum, whilst in _Carpocanistrum_ {1171}the +cephalis is entirely lost, and the inner cavity quite simple. The number of +the feet of the peristome is from nine to twenty, sometimes more. The mouth +is commonly more or less constricted. + + +1. _Carpocanistrum novenum_, n. sp. + +Shell ovate, smooth, one and a third times as long as broad. Pores regular +circular, hexagonally framed, three times as broad as the bars, eight to +ten on the greatest breadth of the shell. Peristome strongly constricted, +one-third as broad as the shell, with nine large ovate lamellar, slightly +convergent feet. + +_Dimensions._--Shell 0.08 long, 0.06 broad; mouth 0.02 broad. + +_Habitat._--South Atlantic, Station 325, surface. + + +2. _Carpocanistrum flosculum_, n. sp. (Pl. 52, fig. 9). + +Shell campanulate, rough, thick-walled, of equal breadth and length. Pores +regular circular, of the same breadth as the bars, twelve to fifteen on the +greatest breadth of the shell. Peristome slightly constricted, with twelve +elegant lanceolate, nearly vertical, a little convergent feet. + +_Dimensions._--Shell 0.07 long, 0.07 broad; mouth 0.05 broad. + +_Habitat._--Equatorial Atlantic, Station 347, surface. + + +3. _Carpocanistrum giganteum_, n. sp. + +Shell ovate, smooth, very thick-walled, one and a third times as long as +broad. Pores very numerous and small, subregular circular, forty to fifty +on the greatest breadth of the shell, of about the same breadth as the +bars. Peristome small, constricted, scarcely one-fourth as broad as the +shell, with twelve to fifteen short triangular vertical feet. + +_Dimensions._--Shell 0.28 to 0.31 long, 0.21 to 0.23 broad; mouth 0.06 to +0.07 broad. + +_Habitat._--Fossil in Barbados. + + +4. _Carpocanistrum acephalum_, n. sp. (Pl. 52, fig. 10). + +Shell ovate, smooth, thin-walled, one and a fifth times as long as broad. +Pores subregular circular, twice as broad as the bars, sixteen to twenty on +the greatest breadth of the shell. Peristome slightly constricted, with +fifteen to eighteen slender, slightly bent, nearly vertical, and parallel +feet, which are half as long as the shell. + +_Dimensions._--Shell 0.12 long, 0.1 broad; mouth 0.07 broad. + +_Habitat._--North Pacific, Station 241, depth 2300 fathoms. + + +{1172}5. _Carpocanistrum evacuatum_, n. sp. (Pl. 52, fig. 11). + +Shell urceolate, smooth, thin-walled, one and a half times as long as +broad. Pores regular circular, sixteen to twenty on the greatest breadth of +the shell. Peristome slightly constricted, with twenty to twenty-five small +triangular vertical feet. + +_Dimensions._--Shell 0.1 long, 0.07 broad; mouth 0.05 broad. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +6. _Carpocanistrum pyriforme_, Haeckel. + + _Lithocarpium pyriforme_, Stoehr, 1880, Palaeontogr., vol. xxvi. p. 97, + Taf. iii. fig. 10. + +Shell pear-shaped or subspherical, one and a fourth times as long as broad. +Pores roundish, polygonally framed (or with square meshes ?). Peristome +strongly constricted, one-fourth as broad as the shell, somewhat tubular, +with twelve to twenty short vertical and parallel feet. The position of +this species is doubtful; perhaps it represents a peculiar genus. + +_Dimensions._--Shell 0.17 long, 0.14 broad; mouth 0.035 broad. + +_Habitat._--Fossil in Tertiary rocks of Sicily (Grotte) Stoehr. + + + +Genus 521. _Arachnocalpis_,[138] Haeckel, 1881, Prodromus, p. 427. + +_Definition._--#Archiphormida# (vel Monocyrtida multiradiata aperta) with +an ellipsoidal or nearly spherical double shell; outer shell arachnoidal or +spongy. Peristome small, constricted with a corona of numerous radial feet. +No apical horn. + +The genus _Arachnocalpis_ differs from the other Archiphormida by +possessing a double shell (like _Peripyramis_). The large shell, reaching +nearly half a millimeter in length is either ellipsoidal or nearly +spherical, and composed of an inner primary and an outer secondary shell. +Its network is very delicate, in the outer envelope either spongy or +arachnoidal. This very remarkable genus has probably no true relation to +the other Archiphormida but has been derived from true #Calpoidea# +(_Mitrocalpis_) by development of a corona around the mouth. + + +1. _Arachnocalpis ellipsoides_, n. sp. (Pl. 98, fig. 13). + +Shell ellipsoidal, one and a half times as long as broad, on the apical +pole hemispherical, on the basal pole coronate, with an elegant prominent +funnel-shaped peristome, which is one-eighth as broad as the shell, +fenestrated by very fine pores, and bears fifteen to twenty short conical +divergent teeth. Inner shell with irregular polygonal meshes of very +different size, separated by thin, {1173}finely-denticulate bars. Outer +spongy shell very delicate, arachnoidal, with numerous prominent conical +spongy papillae. Central capsule ellipsoidal, half as long and broad as the +shell. + +_Dimensions._--Shell 0.46 long, 0.32 broad; mouth 0.045 broad. + +_Habitat._--Central Pacific, Stations 271 to 274, surface. + + +2. _Arachnocalpis sphaeroides_, n. sp. + +Shell spheroidal, of the same structure as the preceding ellipsoidal +species, with the same form of the spongy envelope; differing from it in +the globose form and the shorter peristome, bearing only nine or ten small +conical divergent teeth. Central capsule spherical. + +_Dimensions._--Shell 0.3 diameter, mouth 0.04 broad. + +_Habitat._--Central Pacific, Stations 265 to 270, surface. + + + +Subfamily 2. ARCHIPHAENIDA, Haeckel, 1881, Prodromus, p. 429. + +_Definition._--#Phaenocalpida# with the basal mouth of the shell +fenestrated (vel Monocyrtida multiradiata clausa). + + + +Genus 522. _Phaenocalpis_,[139] n. gen. + +_Definition._--#Archiperida# (vel Monocyrtida multiradiata clausa) with an +internal axial simple columella, prolonged outside into an apical horn. + +The genus _Phaenocalpis_ and the following _Phaenoscenium_ comprise those +Archiphaenida in which the vertical axis of the shell-cavity is occupied by +a simple or branched columella, arising from the centre of the base and +prolonged into an apical horn. This columella may be either the vertical +rod of a _Plectaniscus_ or the remnant of an original ring of +_Petalospyris_. The latter genus differs by its sagittal constriction. + + +1. _Phaenocalpis petalospyris_, n. sp. (Pl. 97, fig. 4). + +Shell subspherical, rough, with irregular, roundish pores, larger than the +bars. Columella straight, central, thin, prolonged into a large apical horn +with three dentate edges. Six basal feet curved, divergent, lamellar, with +a middle rib and dentate edges. + +_Dimensions._--Shell 0.07 long, 0.05 broad; horn and feet 0.06 long. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + +{1174}2. _Phaenocalpis ocellata_, Haeckel. + + _Petalospyris ocellata_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 80, Taf. xxii. fig. 9. + +Shell subspherical, smooth, with irregular roundish pores, about as broad +as the bars. Columella slightly curved and excentric, prolonged into a +slender conical horn of the same length. Six basal feet similar to the +horn, slightly divergent. + +_Dimensions._--Shell 0.06 long, 0.07 broad; horn and feet 0.05 long. + +_Habitat._--Fossil in Barbados. + + +3. _Phaenocalpis carinata_, Haeckel. + + _Petalospyris carinata_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 80, Taf. xxii. fig. 6. + +Shell campanulate, rough, with irregular roundish pores, smaller than the +bars. Columella straight, central, prolonged into a stout conical horn of +the same length. Nine basal feet slender, triangular, longer than the +shell, nearly vertical, with a middle rib in the basal half. + +_Dimensions._--Shell 0.05 long, 0.06 broad; horn 0.04 long, feet 0.08 long. + +_Habitat._--Fossil in Barbados. + + +4. _Phaenocalpis flabellum_, Haeckel. + + _Petalospyris flabellum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, Taf. xxii. fig. 7. + +Shell campanulate smooth, with very small circular pores, half as broad as +the bars. Columella straight, central, prolonged into a pyramidal horn of +half the length. Twelve to fifteen basal feet lamellar, linear, twice to +three times as long as the shell, parallel and vertical, pointed at the +distal end. + +_Dimensions._--Shell 0.04 long, 0.05 broad; horn 0.02 long, feet 0.1 to +0.12 long. + +_Habitat._--Fossil in Barbados. + + + +Genus 523. _Phaenoscenium_,[140] n. gen. + +_Definition._--#Archiphaenida# (vel Monocyrtida multiradiata clausa) with +an internal axial branched columella, prolonged outside into an apical +horn. + +The genus _Phaenoscenium_ differs from the preceding _Phaenocalpis_ in the +branched columella, which is connected by three or six ascending branches +with the inner wall of the shell. It bears therefore to the latter the same +relation that _Cladoscenium_ exhibits to _Euscenium_. The former genera may +have been derived from the latter by interpolation of new interradial feet +between the three primary perradial feet. + + +{1175}1. _Phaenoscenium hexapodium_, n. sp. (Pl. 98, fig. 9). + +Shell campanulate, smooth, about as long as broad. Network delicate, with +irregular polygonal pores and thin bars. Columella with four to six +ascending three-branched verticils, prolonged into the conical hollow +apical horn (with six to eight smaller verticils) which is about as long as +the shell. Six basal feet curved, divergent, of the same length, with +pinnate middle rod. + +_Dimensions._--Shell 0.1 long, 0.11 broad; horn and feet 0.08 to 0.09 long. + +_Habitat._--Central Pacific, Section 271, depth 2425 fathoms. + + +2. _Phaenoscenium cladopodium_, n. sp. + +Shell campanulate, conical, smooth, somewhat broader than long. Network +with irregular roundish pores, about as broad as the bars. Columella with a +single verticil of three ascending branches. Horn pyramidal, stout, as long +as the shell, with three dentate edges. Six feet divergent, slightly +curved, very unequal; three primary (or perradial) very large, longer than +the shell, three sided pyramidal, with three dentate edges; three secondary +(or interradial) much smaller, simple, shorter than the shell. + +_Dimensions._--Shell 0.05 long, 0.06 broad; horn and feet 0.04 to 0.07 +long. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +3. _Phaenoscenium polypodium_, n. sp. + +Shell subspherical, about as long as broad, smooth. Network with regular +circular pores, twice as broad as the bars. Columella with two verticils of +three ascending branches, prolonged into a stout conical horn of twice the +length. Twelve to fifteen conical curved divergent feet, about as long as +the shell. The three primary feet are directly connected with the base of +the columella. + +_Dimensions._--Shell 0.08 diameter, horn 0.15 long, feet 0.07 to 0.09 long. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + + +Genus 524. _Calpophaena_,[141] Haeckel, 1881, Prodromus, p. 429. + +_Definition._--#Archiphaenida# (vel Monocyrtida multiradiata clausa) with +an apical horn and simple internal cavity of the shell without axial +columella. + +The genus _Calpophaena_ and the following closely tied _Archiphaena_ differ +from the two preceding genera of Archiphaenida in the simple shell cavity, +which encloses no columella. They may be derived either from the preceding +_Phaenocalpis_ by loss of the columella, or directly from the Zygospyrida +by reduction of the sagittal constriction and loss of the primary ring. +Different subgenera may be distinguished in _Calpophaena_ according either +to the number of the feet or to their shape (being simple or branched). + + + +{1176}Subgenus 1. _Acrocorona_, Haeckel, 1881, Prodromus, p. 430. + +_Definition._--Feet simple, not branched nor forked. + + +1. _Calpophaena tetrarrhabda_, n. sp. + +Shell subspherical, tuberculate, with subregular circular pores. Apical +horn conical, about as long as the shell. Basal plate with a regular cross +of four equal cortinar pores, separated by four bars; these are crossed in +the sagittal and frontal diameter, and prolonged into four equal conical +divergent feet, about as long as the shell. + +_Dimensions._--Shell 0.1 diameter, horn and feet 0.1 to 0.12 long. + +_Habitat._--South Pacific, Station 297, depth 1775 fathoms. + + +2. _Calpophaena hexarrhabda_, n. sp. (Pl. 53, figs. 17, 18). + +Shell subspherical, rough, with irregular roundish pores. Apical horn +conical, shorter than the shell. Basal plate (fig. 18) with three pairs of +triangular pores, two larger (cardinal) pores in the middle, two smaller +(cervical) at the dorsal, and two intermediate (jugular) at the ventral +side. The bars between them are prolonged into six equal cylindrical +divergent feet, nearly as long as the shell, provided with a spiny knob at +the end. + +_Dimensions._--Shell 0.09 long, 0.08 broad; horn and feet 0.06 to 0.08 +long. + +_Habitat._--Tropical Pacific, Station 224, depth 1850 fathoms. + + +3. _Calpophaena ennearrhabda_, n. sp. + +Shell subspherical, spiny, with irregular, roundish pores. Apical horn +cylindrical, longer than the shell. Basal plate with nine collar pores, +three larger central alternating with three pairs of smaller peripheral +(like Pl. 87, fig. 2). Corona with nine slender cylindrical, slightly +curved, divergent feet, somewhat longer than the shell. + +_Dimensions._--Shell 0.11 long, 0.1 broad; horn and feet 0.12 to 0.15 long. + +_Habitat._--North Pacific, Station 241, depth 2300 fathoms. + + +4. _Calpophaena enneaphylla_, n. sp. + +Shell ovate, smooth, with regular circular pores. Apical horn pyramidal, +half as long as the shell. (Basal plate with four cortinar pores?) Corona +with nine broad, lamellar, truncate, vertical feet, about as long as the +horn. + +_Dimensions._--Shell 0.12 long, 0.09 broad; horn and feet 0.06 long. + +_Habitat._--Central Pacific, Station 271, surface. + + +{1177}5. _Calpophaena petalospyris_, n. sp. + +Shell campanulate, tuberculate, with irregular, roundish pores. Apical horn +conical, shorter than the shell. (Basal plate with nine pores?) Corona with +twelve to twenty broad, lamellar, truncate, vertical feet, of different +sizes, somewhat irregular. + +_Dimensions._--Shell 0.08 long, 0.09 broad; horn and feet 0.07 to 0.12 +long. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + + +Subgenus 2. _Cladocorona_, Haeckel, 1881, Prodromus, p. 430. + +_Definition._--Feet branched or forked. + + +6. _Calpophaena tetracorethra_, n. sp. + +Shell subspherical, smooth, with irregular, roundish pores. Basal plate +with four larger pores. Apical horn and the four divergent basal feet of +equal size and similar form, three to four times as long as the shell, +slender, bristle-shaped, curved, in the distal half irregularly branched. +(Very similar to the remarkable _Tetraspyris tetracorethra_, Pl. 53, figs. +19, 20, but with shorter appendages and with simple spherical shell, which +exhibits no trace of sagittal ring and constriction.) + +_Dimensions._--Shell 0.12 diameter, horn and feet 0.3 to 0.5 long. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +7. _Calpophaena hexacorethra_, n. sp. + +Shell subspherical, smooth, similar to the preceding species. Basal plate +with six pores. Apical horn and the six divergent feet twice to three times +as long as the shell, bristle-shaped, irregularly curved and branched. +(Similar to _Hexaspyris hexacorethra_, Pl. 95, fig. 8, but without sagittal +ring and constriction.) + +_Dimensions._--Shell 0.11 long, 0.13 broad; horn and feet 0.2 to 0.3 long. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + + +Genus 525. _Archiphaena_,[142] Haeckel, 1881, Prodromus, p. 429. + +_Definition._--#Archiphaenida# (vel Monocyrtida multiradiata clausa), with +simple internal cavity of the shell, without apical horn and axial +columella. + +The genus _Archiphaena_ has the same simple cavity of the shell as the +preceding _Calpophaena_, but differs from it in the loss of the apical +horn. It bears therefore to the latter the same relation that _Gorgospyris_ +does to _Petalospyris_. The two former genera may be derived from the two +latter by loss of the sagittal ring and constriction. + + + +{1178}Subgenus 1. _Coronophaena_, Haeckel, 1881, Prodromus, p. 429. + +_Definition._--Feet simple, not branched nor forked. + + +1. _Archiphaena gorgospyris_, n. sp. (Pl. 98, figs. 10, 10_a_). + +Shell hemispherical, smooth, with small subregular, circular pores. Collar +septum with four large pores (fig. 10_a_). Twelve to fifteen feet, +divergent, lamellar, truncate, about as long as the shell. (Similar to +certain forms of _Gorgospyris_, Pl. 87, figs. 1 to 3, but with simple shell +cavity, without sagittal ring and constriction, and without a columella.) + +_Dimensions._--Shell 0.08 long, 0.04 broad; feet 0.03 to 0.04 long. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +2. _Archiphaena corona_, n. sp. + +Shell crown-shaped, somewhat broader than long, at the base flattened, +papillate, with irregular roundish pores. Twenty to twenty-five feet, +broad, lamellar, truncate, nearly vertical, about twice as long as the +shell. + +_Dimensions._--Shell 0.1 long, 0.12 broad; feet 0.2 to 0.22 long. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + + +Subgenus 2. _Stephanophaena_, Haeckel, 1881, Prodromus, p. 429. + +_Definition._--Feet branched or forked. + + +3. _Archiphaena stephanoma_, n. sp. + +Shell campanulate, somewhat longer than broad, with subregular, circular +pores. Margin of the flattened base with a corona of about twenty unequal +feet, which are partly simple, partly irregularly branched, and about as +long as the shell. + +_Dimensions._--Shell 0.11 long, 0.03 broad; feet 0.08 to 0.12 long. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +Family LXI. #CYRTOCALPIDA#, n. fam. + + Archicorida et Archicapsida, Haeckel, 1881, Prodromus, pp. 427, 428. + +_Definition._--#Monocyrtida# eradiata. (#Cyrtoidea# with a simple, not +jointed shell, representing a simple cephalis without radial apophyses.) + +The family #Cyrtocalpida#, composed of the Archicorida and Archicapsida of +my {1179}Prodromus, comprises those #Cyrtoidea# in which the lattice-shell +is quite simple, without transverse constriction, and without radial +apophyses. The two subfamilies differ in the shape of the basal mouth, +which in the Archicorida is a simple wide opening, but in the Archicapsida +is closed by a lattice-plate. + +Only a few species of this family were formerly known. Ehrenberg, in 1838, +founded upon these the genus _Cornutella_, one of the three oldest genera +of Polycystina (_Cornutella_, _Lithocampe_, _Haliomma_). In 1862 I +described some living forms, with a central capsule, as _Cyrtocalpis_. The +Challenger collection contains a large number of new genera and species. + +Probably the family Cyrtocalpida is an artificial group, comprising two or +more different subfamilies of very different origin. The Cornutellida +(_Cornutella_, _Cornutanna_) have probably been derived from the +Sethocorida by loss of the cephalis, so that their conical shell represents +a thorax alone. The Mitrocalpida on the other hand (genera 528-531) may be +originally simple ovate shells (like _Gromia_ and _Lecythium_), arising +independently from the Nassellida. The Archicapsida (_Halicapsa_, +_Archicapsa_) are probably derived from the Zygospyrida (_Dictyospyris_, +_Circospyris_) by loss of the sagittal ring and constriction. This is +nearly certain, when the three or four typical cortinar pores appear in +their basal plate. Some forms of _Halicapsa_ may be easily confounded with +some forms of Prunoidea (_Lithapium_). + +Those Cyrtocalpida, which possess a central capsule with three or four +lobes, are probably derived from Tripocyrtida by loss of the three feet, or +from Sethocyrtida by loss of the cephalis, since the lobes indicate the +original presence of cortinar pores and of a cephalis. Those Cyrtocalpida, +however, in which a simple ovate shell encloses a simple central capsule +without lobes, may be original "Monocyrtida eradiata," without relation to +any radial ancestral forms. + +_Synopsis of the Genera of Cyrtocalpida._ + + ------------------------------------------------------------------------- + I. Subfamily Archicorida. Basal mouth of the shell a simple wide opening. + -------------------- + Shell with simple lattice-work (not double or spongy). + ------------------------------------------------------------------------- + Shell conical, gradually { With horn, 526. _Cornutella_. + dilated towards { + the mouth. { No horn, 527. _Cornutanna_. + + Shell ovate or urceolate, { With horn, 528. _Archicorys_. + with constricted { + mouth. { No horn, 529. _Cyrtocalpis_ + ------------------------------------------------------------------------- + Shell not simply latticed. + ------------------------------------------------------------------------- + Shell ovate, double, with an external 530. _Mitrocalpis_. + mantle, + + Shell ovate, with spongy irregular, + lattice-work 531. _Spongocyrtis_. + ------------------------------------------------------------------------- + II. Subfamily Archicapsida. Mouth closed by a lattice plate. + ------------------------------------------------------------------------- + Shell with an apical horn, 532. _Halicapsa_. + + Shell without horn on the apex, 533. _Archicapsa_. + + + +{1180}Subfamily 1. ARCHICORIDA, Haeckel, 1881, Prodromus, p. 427. + +_Definition._--#Cyrtocalpida#, with the basal mouth of the shell open (vel +Monocyrtida eradiata aperta). + + + +Genus 526. _Cornutella_,[143] Ehrenberg, 1838, Abhandl. d. k. Akad. d. +Wiss. Berlin, p. 128. + +_Definition._--#Archicorida# with conical shell, gradually dilated towards +the wide open mouth. Apex armed with a horn. + +The genus _Cornutella_ is one of the three oldest genera of Polycystina, +described by Ehrenberg, in 1838 (_Cornutella_, _Lithocampe_, and +_Haliomma_). He afterwards enumerated, in 1872 and 1875, a large number of +fossil and living species, the majority of which, however, belong to other +genera of Monocyrtida and Dicyrtida (at least six or seven different +genera). We retain here as the true type of the genus the oldest known +species:--_Cornutella clathrata_, and the nearly allied forms _Cornutella +stylophaena_, _Cornutella mitra_, _Cornutella circularis_, &c. The simple +conical shell exhibits no distinct trace of an original cephalis, excepting +the apical horn; it may have originated either independently, or been +derived from _Sethoconus_, by loss of the cephalis. + + + +Subgenus 1. _Cornutellium_, Haeckel. + +_Definition._--Axis of the conical shell straight. Pores polygonal, or +roundish with polygonal frames. + + +1. _Cornutella hexagona_, n. sp. (Pl. 54, fig. 9). + +Shell slender, conical, with straight outlines. Pores subregular, +hexagonal, gradually increasing in size towards the mouth; in about ten to +twelve longitudinal series, in the upper part very small. Horn slenderly +conical, nearly bristle-shaped, long. + +_Dimensions._--Shell 0.1 to 0.15 long, 0.04 to 0.06 broad. + +_Habitat._--Central Pacific, Stations 265 to 274, surface, and at different +depths. + + +2. _Cornutella sethoconus_, n. sp. (Pl. 54, fig. 10). + +Shell slender, conical, with undulate outlines. Pores subregular, +hexagonal, gradually increasing in size towards the mouth, in about fifteen +to eighteen longitudinal series, in the upper part circular. Horn small, +conical, short. The network is not so delicate as in the preceding similar +species. + +_Dimensions._--Shell 0.12 to 0.16 long, 0.06 to 0.08 broad. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +{1181}3. _Cornutella distenta_, Ehrenberg. + + _Cornutella distenta_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 287, Taf. vi. III. fig. 3. + +Shell slender, conical, with straight outlines. Pores small, circular, +regularly disposed in six to eight alternating longitudinal rows, each pore +surrounded by a large rhombic frame. The connected frames form together a +regular rhombic framework with obliquely crossed crests. Horn conical, +stout, large. + +_Dimensions._--Shell 0.1 to 0.15 long, 0.04 to 0.06 broad. + +_Habitat._--North Pacific, Californian Sea, depth 2600 fathoms, Ehrenberg. + + +4. _Cornutella stiligera_, Ehrenberg. + + _Cornutella stiligera_, Ehrenberg, 1854, Mikrogeol., Taf. xxxvi. fig. 1; + Abhandl. d. k. Akad. d. Wiss. Berlin, 1875, p. 68, Taf. ii. fig. 3. + +Shell slender, conical, with straight outlines. Pores subregular, rhombic +or nearly square, disposed in oblique series, separated by parallel +obliquely ascending rings, which are crossed by interrupted parallel bars. +Horn slenderly conical or bristle-shaped, thin and long. + +_Dimensions._--Shell 0.08 to 0.12 long, 0.03 to 0.04 broad. + +_Habitat._--Fossil in Barbados. + + + +Subgenus 2. _Cornutissa_, Haeckel, 1881, Prodromus, p. 427. + +_Definition._--Axis of the conical shell straight. Pores circular or +roundish, without polygonal frames. + + +5. _Cornutella circularis_, Ehrenberg. + + _Cornutella circularis_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 68, Taf. ii. fig. 4. + +Shell wide, conical or funnel-shaped, with straight outlines. Pores very +large, circular, ten to twenty times as broad as the bars, in about nine to +twelve longitudinal alternating rows, increasing gradually towards the +mouth. Horn very large, cylindrical. + +_Dimensions._--Shell 0.1 to 0.15 long, 0.08 to 0.12 broad. + +_Habitat._--Fossil in Barbados. + + +6. _Cornutella mitra_, Ehrenberg. + + _Cornutella mitra_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 68, Taf. ii. fig. 8. + +Shell wide, conical, campanulate, with convex outlines. Pores subregular, +circular, nearly equal in size, not regularly disposed in rows. Horn +conical, stout. + +_Dimensions._--Shell 0.12 to 0.16 long, 0.08 to 0.12 broad. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms; also fossil +in Barbados. + + +{1182}7. _Cornutella clathrata_, Ehrenberg. + + _Cornutella clathrata_, Ehrenberg, 1838, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, p. 129; Mikrogeol., Taf. xxii. fig. 39. + + _Cornutella clathrata_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, Taf. ii. fig. 9. + +Shell wide, conical with slightly convex outlines. Pores regular, circular, +gradually increasing in size towards the mouth, disposed in twelve to +fifteen longitudinal alternating rows. Horn short and stout, conical. +(Compare _Cornutella curvata_.) + +_Dimensions._--Shell 0.15 to 0.2 long, 0.06 to 0.09 broad. + +_Habitat._--Cosmopolitan; Atlantic, Indian, Pacific; also fossil in +tertiary rocks of Barbados, Nikobar and Sicily. + + +8. _Cornutella stylophaena_, Ehrenberg. + + _Cornutella stylophaena_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 287, Taf. vi. III. fig. 1. + + ? _Cornutella tumens_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 287, Taf. vi. III. fig. 4. + +Shell slender, conical, with undulate outlines. Pores subregular, circular, +gradually increasing in size, disposed in six to nine quincuncial +alternating longitudinal rows. Horn very long, cylindro-conical, sometimes +about as long as the shell. + +_Dimensions._--Shell 0.1 to 0.13 long, 0.04 to 0.06 broad. + +_Habitat._--North Pacific, Californian Sea, depth 2600 fathoms. + + +9. _Cornutella granulata_, Ehrenberg. + + _Cornutella granulata_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 287, Taf. vi. III. fig. 5. + +Shell slender, conical, nearly cylindrical, with straight outlines, rounded +at the apex. Pores very small and numerous, punctiform, disposed into very +numerous parallel transverse rows. Horn small, conical (may be perhaps the +shell of a Tintinnoid Infusorium?). + +_Dimensions._--Shell 0.08 long, 0.02 broad. + +_Habitat._--North Pacific, Californian Sea, depth 2600 fathoms. + + +10. _Cornutella annulata_, Ehrenberg. + + _Cornutella annulata_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 287, Taf. ii. fig. 16. + +Shell slender, conical, nearly cylindrical, with straight outlines, rounded +at the apex. Pores small and numerous, regular circular, of equal size, +regularly disposed in ten to fifteen parallel transverse series. Horn +bristle-shaped. (Compare _Artostrobus annulatus_, _Cornutella annulata_, +Bailey.) + +_Dimensions._--Shell 0.1 to 0.13 long, 0.03 to 0.04 broad. + +_Habitat._--Cosmopolitan, Atlantic, Pacific, surface. + + + +{1183}Subgenus 3. _Cornutosa_, Haeckel, 1881, Prodromus, p. 427. + +_Definition._--Axis of the conical shell curved. Pores circular or +roundish. + + +11. _Cornutella curvata_, Haeckel. + + _Cornutella clathrata_, var., Ehrenberg, 1854, Mikrogeol., Taf. xxii. + figs. 39_a_, _b_, _c_. + + _Cornutosa clathrata_, Haeckel, 1881, Prodromus, p. 427. + +Shell slender, conical, with curved axis; the curve lies in one plane and +is not spirally convoluted. Pores subregular, circular, of nearly equal +size, quincuncially disposed. Horn short, conical. + +_Dimensions._--Shell 0.1 to 0.15 long, 0.04 to 0.06 broad. + +_Habitat._--Fossil in tertiary rocks of Sicily (Caltanisetta). + + +12. _Cornutella spiralis_, n. sp. + + _Cornutura spiralis_, Haeckel, 1881, Prodromus, p. 427. + +Shell slender, conical, nearly cylindrical, very long, spirally contorted; +its axis is an ascending spiral line with two or three windings, widely +distant. Pores irregular, square, small and numerous. + +_Dimensions._--Shell 0.2 to 0.25 long, 0.05 to 0.08 broad. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +Genus 527. _Cornutanna_,[144] Haeckel, 1881, Prodromus, p. 427. + +_Definition._--#Archicorida# with conical shell, gradually dilated towards +the wide open mouth. Apex without horn. + +The genus _Cornutanna_ has the same simple conical shell as the preceding +_Cornutella_, but differs from it in the total absence of an apical horn. +It bears therefore to the latter the same relation that _Cyrtocalpis_ does +to _Archicorys_. It may be derived from _Sethoconus_ by complete reduction +of the cephalis and its horn. + + +1. _Cornutanna orthoconus_, n. sp. + +Shell slender, conical, with straight axis and straight outlines. Pores +subregular, circular, quincuncially disposed in nine to twelve alternating +longitudinal series, gradually increasing in size towards the mouth. + +_Dimensions._--Shell 0.1 to 0.12 long, 0.03 to 0.04 broad. + +_Habitat._--Central Pacific, Stations 270 to 274, surface. + + +{1184}2. _Cornutanna cyrtoconus_, n. sp. + +Shell slender, conical, with curved axis; the curve lies in one plane as in +the similar _Cornutella curvata_; the pores are smaller and more numerous +than in this latter species, and the rounded apex bears no horn. + +_Dimensions._--Shell 0.12 to 0.16 long, 0.05 to 0.07 broad. + +_Habitat._--South Pacific, Station 300, depth 1375 fathoms. + + +3. _Cornutanna loxoconus_, n. sp. + +Shell wide, conical, with irregularly curved axis; the parts of the curve +do not lie in one plane. Pores very small and numerous, of nearly equal +size. + +_Dimensions._--Shell 0.2 long, 0.12 broad. + +_Habitat._--Tropical Pacific, Station 225, depth 4475 fathoms. + + + +Genus 528. _Archicorys_,[145] Haeckel, 1881, Prodromus, p. 427. + +_Definition._--#Archicorida# with simple urceolate or ovate shell, +constricted towards the mouth. Apex armed with a horn. + +The genus _Archicorys_ and the following closely allied _Cyrtocalpis_ +differ from the two preceding genera in the ovate or urceolate form of the +shell, which is more or less constricted towards the terminal mouth. The +upper pole in _Archicorys_ bears an apical horn, which is absent in +_Cyrtocalpis_. The origin of these two genera may be the same, probably +arising directly from Nassellida, and independently of the triradiate +#Cyrtoidea# or bilocular #Spyroidea#. (Compare p. 1179.) + + +1. _Archicorys galea_, n. sp. + +Shell smooth urceolate. Pores large, in the middle part hexagonal, towards +both ends smaller and polygonal. Apical horn stout, three-sided pyramidal, +half as long as the shell. Mouth with a short tubular peristome, about +one-third as broad as the shell. + +_Dimensions._--Shell (without horn) 0.15 long, 0.12 broad; horn 0.07 long, +mouth 0.05 broad. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +2. _Archicorys ampulla_, n. sp. + +Shell smooth, thin-walled, bottle-shaped, in the upper half conical, in the +lower half inflate, subspherical. Pores subregular, circular, of the same +breadth as the bars. Horn conical, stout, {1185}/about one-third as long as +the shell. Mouth truncate, without peristome, about half as broad as the +shell. + +_Dimensions._--Shell 0.15 long, 0.1 broad; horn 0.05, mouth 0.05. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +3. _Archicorys microstoma_, n. sp. (Pl. 51, fig. 12). + +Shell rough, thick-walled, ovate. Pores large, subregular, circular, twice +to four times as broad as the bars. Horn small, conical, not larger than +one pore. Mouth very small, truncate, scarcely larger than one pore. + +_Dimensions._--Shell 0.1 long, 0.07 broad; horn 0.012, mouth 0.015. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +4. _Archicorys globosa_, n. sp. + +Shell nearly spherical, thorny, thick-walled. Pores very large, circular, +separated by spinulate frames, smaller towards each pole. Horn conical, +large, nearly as long as the radius of the shell; mouth truncate, simple, +about one-third as broad as the shell. + +_Dimensions._--Shell diameter 0.13, horn 0.06, mouth 0.04. + +_Habitat._--Fossil in Barbados. + + +5. _Archicorys ovata_, n. sp. (Pl. 51, fig. 10). + +Shell ovate, rough, thick-walled. Pores regular, circular, of equal size, +very small and numerous, quincuncially disposed. Horn small, conical, +sometimes (as in the figured specimen) rudimentary. When it becomes lost, +the species may be called _Cyrtocalpis ovata_. Mouth truncate, small, +simple, one-sixth as broad as the shell. + +_Dimensions._--Shell 0.2 long, 0.15 broad; horn 0.01 to 0.03 long, mouth +0.03 broad. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + + +Genus 529. _Cyrtocalpis_,[146] Haeckel, 1860, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 835. + +_Definition._--#Archicorida# with simple urceolate or ovate shell, +constricted towards the mouth. Apex without horn. + +The genus _Cyrtocalpis_ comprises a large number of common, very primitive +Monocyrtida, which in the simple ovate or urceolate form of the shell +resemble the well known _Gromia_ among the Thalamophora. Its basal mouth is +more or less constricted, as in {1186}the preceding genus _Archicorys_, +from which it differs in the total absence of an apical horn. There is no +trace of any triradial structure, excepting in some smaller species, in +which the basal part of the central capsule is trilobate; these may be +derived from the Dicyrtides _Sethocorys_ or _Dictyocephalus_, by loss of +the cephalis and the cortinar septum. But the larger species, which have a +quite simple, ovate, central capsule (Pl. 51, fig. 13), have probably an +independent origin, from _Cystidium_. + + +1. _Cyrtocalpis urceolus_, n. sp. (Pl. 51, fig. 13). + +Shell smooth, urceolate, with very delicate and elegant network. Pores in +the middle part large, regular, hexagonal, towards each pole smaller, +irregular, roundish or polygonal. Mouth with broad, hyaline, annular +peristome, about one-third as broad as the shell. + +_Dimensions._--Shell 0.16 long, 0.12 broad; mouth 0.05 broad. + +_Habitat._--Mediterranean (Portofino near Genoa), surface. + + +2. _Cyrtocalpis reticulum_, n. sp. + +Shell smooth, urceolate, very similar to the preceding species, but +differing from it in the densely reticulated framework of the shell, which +is composed of very numerous and small, irregular, polygonal meshes of +nearly equal size. Mouth without peristome, half as broad as the shell. + +_Dimensions._--Shell 0.18 long, 0.15 broad; mouth 0.07 broad. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + +3. _Cyrtocalpis amphora_, Haeckel. + + _Cyrtocalpis amphora_, Haeckel, 1862, Monogr. d. Radiol., p. 286, Taf. v. + fig. 2. + +Shell smooth, urceolate with regular, circular pores of equal size, of +about the same breadth as the bars. Mouth with smooth peristome, about half +as broad as the shell. + +_Dimensions._--Shell 0.12 long, 0.08 broad; mouth 0.04 broad. + +_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Pacific; surface, and at +various depths. + + +4. _Cyrtocalpis urna_, Stoehr. + + _Cyrtocalpis urna_, Stoehr, 1880, Palaeontogr., vol. xxvi. p. 96, Taf. + iii. fig. 7. + +Shell smooth, urceolate, with subregular, circular pores of different +sizes, gradually increasing towards the mouth, of about the same breadth as +the bars. Mouth without peristome (?), about half as broad as the shell. + +_Dimensions._--Shell 0.09 long, 0.06 broad; mouth 0.035 broad. + +_Habitat._--Fossil in tertiary rocks of Sicily (Grotte). + + +{1187}5. _Cyrtocalpis sethopora_, n. sp. (Pl. 52, fig. 4). + +Shell smooth, urceolate, very thin-walled, with large irregular roundish +meshes, each of which is closed by a thin porous sieve-plate. Mouth +two-thirds as broad as the shell, with a broad, emarginate, longitudinally +striped peristome. (Perhaps the shell of a Tintinnoid Infusorium?) + +_Dimensions._--Shell 0.08 long, 0.05 broad; mouth 0.03 broad. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +6. _Cyrtocalpis compacta_, n. sp. (Pl. 52, figs. 7, 8). + +Shell smooth, ovate, very thick-walled, with small, subregular, circular +pores of equal size, perpendicularly perforating the wall, about half as +broad as the bars. Mouth small, only one-third as broad as the compact +shell. (Perhaps a reduced _Lithocampe_ or _Lithomitra_?) + +_Dimensions._--Shell 0.08 long, 0.04 broad; mouth 0.015 broad. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms; also fossil +in Barbados. + + +7. _Cyrtocalpis lithomitra_, n. sp. (Pl. 52, figs. 5, 6). + +Shell smooth, slender, ovate, nearly cylindrical, with small subregular, +circular pores, which are disposed in nine to twelve transverse rows, and +obliquely ascending perforate the wall. Mouth wide, without peristome, +about two-thirds as broad as the shell. (Compare _Lithomitra_, Pl. 79.) + +_Dimensions._--Shell 0.09 long, 0.045 broad; mouth 0.03 broad. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms; also fossil +in Barbados. + + +8. _Cyrtocalpis ovulum_, n. sp. + + _Cyrtocalpis obliqua_, var. _ovulum_, Haeckel, 1862, Monogr. d. Radiol., + p. 286, Taf. v. fig. 3. + +Shell smooth, broad, ovate, with very numerous and small regular circular +pores, quincuncially disposed, twice as broad as the bars. Mouth without +peristome, about half as broad as the shell. + +_Dimensions._--Shell 0.09 long, 0.047 broad; mouth 0.04 broad. + +_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Pacific, surface. + + +9. _Cyrtocalpis obliqua_, Haeckel. + + _Cyrtocalpis obliqua_, Haeckel, 1862, Monogr. d. Radiol., p. 286, Taf. v. + figs. 4-11. + +Shell smooth, irregularly ovate, more or less oblique, variable in size and +form, sometimes nearly spherical, at other times subcylindrical. Pores +subregular, circular, once or twice the breadth of the bars. Mouth simple +without peristome, about half as broad as the shell. + +_Dimensions._--Shell 0.07 to 0.1 long, 0.05 to 0.08 broad; mouth 0.03 to +0.04 broad. + +_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Pacific, surface. + + +{1188}10. _Cyrtocalpis gromia_, n. sp. (Pl. 51, fig. 11). + +Shell rough, ovate, very thick-walled, with subregular, circular pores of +somewhat variable size. The diameter of the internal, simple, subspherical +cavity is five to six times as great as the thickness of the wall. Mouth +tubular, cylindrical, very narrow, only one-sixth as broad as the shell. + +_Dimensions._--Shell 0.16 long, 0.11 broad; mouth 0.02 broad. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + + +Genus 530. _Mitrocalpis_,[147] Haeckel, 1881, Prodromus, p. 427. + +_Definition._--#Archicorida# with a double ovate or ellipsoidal shell, +composed of two parallel lattice-plates, which are connected by numerous +beams. Apex without horn. + +The genus _Mitrocalpis_ and the following closely allied _Spongocyrtis_ +differ from the four preceding genera of Archicorida in the complicated +structure of the shell-wall, which in the former is double, in the latter +spongy. The mouth is in both genera constricted, narrow, and the apex +without a horn. _Mitrocalpis_ has been derived probably from _Cyrtocalpis_ +in the same way as _Peripyramis_ from _Bathropyramis_, by development of +spines on the surface of the shell, which at equal distances from the +latter become connected by branches, thus forming an outer envelope. + + +1. _Mitrocalpis palliata_, n. sp. + +Shell ellipsoidal, large, one and a third times as long as broad. Inner +shell very thin-walled, with irregular, polygonal pores of very variable +size and form. From its nodal points there arise numerous bristle-shaped +radial beams, about as long as the diameter of the mouth, which are +connected at equal distances from the surface by delicate threads, forming +the outer enveloping shell. The surface of the latter is smooth. The thin +bars of the inner shell are twice to four times as broad as those of the +outer. Mouth about one-seventh as broad as the shell, with a short tubular +peristome. + +_Dimensions._--Shell 0.35 long, 0.27 broad; mouth 0.04, distance of both +shells 0.037. + +_Habitat._--Central Pacific, Station 271, surface. + + + +Genus 531. _Spongocyrtis_,[148] Dunikowski. + + _Spongocyrtis_, Dunikowski, 1882, Denkschr. d. k. Akad. d. Wiss. Wien, + vol. xlv. p. 31. + +_Definition._--#Archicorida# with a spongy ovate shell, the wall of which +is composed of irregular spongy wickerwork. Apex without horn. + +The genus _Spongocyrtis_ differs from most other Monocyrtida in the spongy +structure of the shell, which is found in only very few other genera of +#Cyrtoidea#, e.g., in _Spongopyramis_ and _Spongomelissa_. It has been +derived either from the similar {1189}_Cyrtocalpis_ by development of +irregular spongy wickerwork on the surface of the simple lattice-shell; or +from _Arachnocalpis_ (Pl. 98, fig. 13) by loss of the peristome. + + +1. _Spongocyrtis montis ovis_, Dunikowski. + + _Spongocyrtis montis ovis_, Dunikowski, 1882, Denkschr. d. k. Akad. d. + Wiss. Wien, vol. xlv. p. 31, Taf. vi. figs. 67, 68. + +Shell broad, ovate, rough, spongy, thick-walled; length to the breadth = +4 : 3. Spongy framework very dense and dark, with very small roundish +pores. Mouth constricted, with a short tubular peristome, about one-third +as broad as the shell. + +_Dimensions._--Shell 0.35 long, 0.26 broad; mouth 0.08 broad. + +_Habitat._--Fossil in the Alpine Lias (Schafberg bei Salzburg, Dunikowski). + + +2. _Spongocyrtis arachnoides_, n. sp. + +Shell ellipsoidal, spiny, spongy, thin-walled; length to the breadth = +3 : 2. Spongy framework loose and delicate, with irregular polygonal meshes +and arachnoidal thread-like bars. Mouth constricted, without peristome, +about one-fifth as broad as the shell. (Very similar to _Arachnocalpis +ellipsoides_, Pl. 98, fig. 13, but without corona around the mouth.) + +_Dimensions._--Shell 0.32 long, 0.21 broad; mouth 0.04 broad. + +_Habitat._--Central Pacific, Station 270, depth 2925 fathoms. + + + +Subfamily 2. ARCHICAPSIDA, Haeckel, 1881, Prodromus, p. 428. + +_Definition._--#Cyrtocalpida#, with the basal mouth of the shell +fenestrated (vel Monocyrtida eradiata clausa). + + + +Genus 532. _Halicapsa_,[149] Haeckel, 1881 Prodromus, p. 429. + +_Definition._--#Archicapsida# with an apical horn. + +The genus _Halicapsa_, and the following closely allied _Archicapsa_, +represent together the small subfamily of Archicapsida, or of those +Cyrtocalpida, in which the basal mouth of the simple shell is closed by a +lattice plate. This may be the original state of this family, if it is +derived from the Circospyrida (_Circospyris_, _Dictyospyris_) by loss of +the sagittal constriction and the primary ring. But it is also possible +that the Archicapsida have been partly derived from the Archicorida by +secondary fenestration of the open mouth. The genus _Halicapsa_ may be +easily confounded with the similar Ellipsid _Lithapium_ (compare p. 303, +Pl. 14, figs. 8-10). The skeleton of both genera may be perfectly similar, +the only distinction being the structure of the central capsule, which in +_Halicapsa_ is that of the MONOPYLEA, in _Lithapium_ that of the PERIPYLEA. + + + +{1190}Subgenus 1. _Calpocapsa_, Haeckel. + +_Definition._--Surface of the shell smooth or rough, but not spiny. + + +1. _Halicapsa lithapium_, n. sp. (Pl. 97, fig. 6). + +Shell pear-shaped, rough, one and a half times as long as broad. Pores +subregular, circular, twice as broad as the bars. Basal plate with four +larger ovate cortinar pores (two larger cardinal and two smaller jugular), +and with six smaller peripheral pores (fig. 6). Horn of the apex +three-sided pyramidal, stout, half as long as the shell. + +_Dimensions._--Shell 0.16 long, 0.1 broad; horn 0.08 long. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +2. _Halicapsa triglochin_, n. sp. (Pl. 53, figs. 3, 4). + +Shell ovate, rough, a little longer than broad. Pores regular, circular, +hexagonally framed, of the same breadth as the bars. Basal plate (fig. 4) +without larger pores. Horn pyramidal, stout, about half as long as the +shell, with three short, horizontally divergent secondary spines at the +base (possibly remnants of three original cortinar feet?) + +_Dimensions._--Shell 0.11 long, 0.09 broad; horn 0.06 long. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +3. _Halicapsa prunoides_, n. sp. + +Shell pear-shaped, tuberculate, a little longer than broad. Pores +irregular, roundish, of different sizes. Basal plate with four larger and +six smaller pores. Horn pyramidal, stout, about one-third as long as the +shell. (May belong perhaps to the similar #Prunoidea# _Lithapium_, compare +p. 303 and Pl. 14, figs. 8-10.) + +_Dimensions._--Shell 0.14 long, 0.12 broad; horn 0.05 long. + +_Habitat._--Fossil in Barbados. + + + +Subgenus 2. _Echinocapsa_, Haeckel, 1881, Prodromus, p. 429. + +_Definition._--Surface of the shell spiny, covered with thorns, papillae or +larger spines. + + +4. _Halicapsa papillata_, n. sp. + +Shell bottle-shaped, papillate, one and a half times as long as broad. +Pores circular, much larger in the middle part than towards the poles. The +elevated frames between them bear on the {1191}nodal points large blunt +conical papillae. Basal plate without larger pores. Horn three-sided +pyramidal, one-third as long as the shell, gradually passing into the +slender neck of the bottle. + +_Dimensions._--Shell 0.22 long, 0.15 broad; horn 0.07 long. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +5. _Halicapsa pyriformis_, Haeckel. + + ? _Haliomma pyriforme_, Bailey, 1856, Amer. Journ. Sci. and Arts, vol + xxii. p. 1, pl. i. fig. 29. + +Shell pear-shaped, a little longer than broad, covered with numerous short +conical spines. Pores subregular, circular, of nearly equal size, twice as +broad as the bars. Basal plate with four crossed larger ovate pores (two +larger cardinal and two smaller jugular pores). Horn stout pyramidal, +scarcely one-fourth as long as the shell. + +_Dimensions._--Shell 0.16 long, 0.14 broad; horn 0.04 long. + +_Habitat._--Fossil in Barbados, living in the North Pacific (Kamtschatka)? + + +6. _Halicapsa hystrix_, n. sp. (Pl. 53, figs. 5, 6). + +Shell pear-shaped, subspherical, a little longer than broad, with scattered +stout pyramidal spines about as long as the radius of the shell. Pores +subregular, circular, three times as broad as the bars. Basal plate (fig. +6) without larger pores. Horn very large, pyramidal, longer than the shell. + +_Dimensions._--Shell 0.1 long, 0.09 broad; horn 0.13 long. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + + +Genus 533. _Archicapsa_,[150] Haeckel, 1881, Prodromus, p. 428. + +_Definition._--#Archicapsida# without apical horn. + +The genus _Archicapsa_ differs from the preceding _Halicapsa_ in the +absence of the apical horn, and represents the simplest form among the +Monocyrtida clausa, a simple, ovate, or pear-shaped shell without any +appendages. The characteristic structure of the basal lattice-plate (with +three or four large cortinar pores) makes it probable that _Archicapsa_ has +been derived either from _Halicapsa_, by loss of the horn, or directly from +_Dictyospyris_, by reduction of the sagittal ring and constriction. + + +1. _Archicapsa triforis_, n. sp. (Pl. 53, figs. 1, 2). + +Shell pear-shaped, smooth, one and a half times as long as broad. Pores +subregular, circular, of about the same breadth as the bars. Basal plate +(fig. 2) with three very large pores, three times as broad as the others +(one odd sternal pore and two paired cardinal pores). + +_Dimensions._--Shell 0.09 long, 0.06 broad. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +{1192}2. _Archicapsa quadriforis_, n. sp. + +Shell ovate, rough, a little longer than broad. Pores subregular, circular, +twice as broad as the bars. Basal plate with four larger ovate cortinar +pores (two smaller jugular and two larger cardinal pores). + +_Dimensions._--Shell 0.12 to 0.15 long, 0.1 to 0.12 broad. + +_Habitat._--Central Pacific, Station 265 to 268, depth 2700 to 2900 +fathoms. + + +3. _Archicapsa nonaforis_, n. sp. + +Shell pear-shaped, thorny, one and a half times as long as broad. Pores +regular, circular, small, hexagonally framed, twice as broad as the bars. +Basal plate with nine cortinar pores (three larger alternating with three +pairs of smaller pores, as in Pl. 87, fig. 2). + +_Dimensions._--Shell 0.14 long, 0.09 broad. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +---- + + +Section II. DICYRTIDA, Haeckel, 1862, Monogr. d. Radiol., pp. 280, 296. + +_Definition._--#Cyrtoidea# dithalamia, with two-jointed shell, being +divided by a transverse collar stricture into an apical joint (or cephalis) +and a basal joint (or thorax). + +_Synopsis of the three Families and six Subfamilies of Dicyrtida._ + + Family LXII. Tripocyrtida. { Mouth open, 1. Sethopilida. + { + Three radial apophyses. { Mouth closed, 2. Sethoperida. + + Family LXIII. Anthocyrtida. { Mouth open, 3. Sethophormida. + { + Numerous radial apophyses. { Mouth closed, 4. Sethophaenida. + + Family LXIV. Sethocyrtida. { Mouth open, 5. Sethocorida. + { + No radial apophyses. { Mouth closed, 6. Sethocapsida. + + + +Family LXII. #TRIPOCYRTIDA#, n. fam. + + _Sethopilida et Sethoperida_, Haeckel, 1881, Prodromus, pp. 431, 433. + +_Definition._--#Dicyrtida# triradiata. (#Cyrtoidea# with a two-jointed +shell, divided by a transverse constriction into cephalis and thorax, and +bearing three radial apophyses.) + +{1193}The family #Tripocyrtida#, composed of the Sethopilida and +Sethoperida of my Prodromus, comprises those #Cyrtoidea# in which the +lattice-shell is two-jointed and bears three radial apophyses. The two +subfamilies differ in the shape of the mouth, which in the Sethopilida is a +simple wide opening, but in the Sethoperida is closed by a lattice-plate; +the former are here divided into sixteen, the latter into eight different +genera. Though probably the two shell-joints are not truly homologous in +all Tripocyrtida, we call the first joint here, as in all Dicyrtida, the +cephalis, and the second joint the thorax. + +Numerous Tripocyrtida, living as well as fossil forms, were formerly +described by Ehrenberg. His genera _Dictyophimus_, _Clathrocanium_, +_Lithomelissa_, and _Lychnocanium_ belong to the Sethopilida, and have the +mouth open; his genera _Lithopera_ and _Lithochytris_ (partly) belong to +the Sethoperida, and have the basal mouth closed by a lattice-plate. Many +of these Tripocyrtida belong probably to the oldest forms of Dicyrtida, are +nearly related to the Phormospyrida, and therefore of special phylogenetic +interest, as was demonstrated by Buetschli (1882, _loc. cit._, pp. +514-519). This near relation to certain #Spyroidea# (_Tripospyris_, +_Acrospyris_, &c.) is particularly striking in some forms of +_Clathrocanium_, _Lithomelissa_, &c. Some other Tripocyrtida seem to +possess a closer relation to certain #Plectoidea# (_Plagoniscus_, +_Plectaniscus_), so mainly some forms of _Tripocyrtis_ and _Dictyophimus_. + +The cephalis, or the first joint of the shell, corresponds usually to the +whole shell of the Zygospyrida and of numerous Monocyrtida, and exhibits +various modifications of shape, which have been already described in these +latter families. It is usually subspherical or hemispherical and armed with +an apical horn. In a small number of genera the horn is lost, in some other +genera multiplied. The cephalis is separated from the thorax not only +externally by the collar constriction, but commonly also internally by a +transverse horizontal fenestrated septum, which usually exhibits three or +four characteristic cortinar pores. The central capsule, originally +enclosed in the cephalis, develops usually three or four large pear-shaped +caecal sacs which pass through the cortinar pores and depend into the +thorax (Pl. 55, figs. 2-11; Pl. 60, figs. 3-7, &c.). + +The thorax in this family exhibits a great variety of interesting +modifications, mainly in the development of the three radial apophyses +arising from it. These may be either enclosed in the wall of the thorax as +ribs, or arise as free wings, very often prolonged over the mouth as three +terminal feet. Finally the three terminal feet only remain, whilst the +original ribs are lost. The special ornamentation of these three apophyses +exhibits an extraordinary variety and elegancy of structure, and many +Tripocyrtida belong, no doubt, to the most graceful and admirable forms of +NASSELLARIA. + +{1194}_Synopsis of the Genera of Tripocyrtida._ + + ------------------------------------------------------------------------- + I. Subfamily Sethopilida. + Terminal mouth of the thorax a simple wide opening. + -------------------- + A. Three radial ribs (or cortinar rods) partly or completely enclosed in + the wall of the thorax. No latticed vertical cephalic wings. + ------------------------------------------------------------------------- + a. Three thoracic { { Feet solid, 534. _Dictyophimus_. + ribs prolonged { Cephalis { + into three { with a horn. { Feet latticed, 535. _Tripocyrtis_. + terminal feet. { + { No horn, feet solid, 536. _Sethopilium_. + + { Thorax { With horn, 537. _Lithomelissa_. + { perfectly { + b. Three thoracic { latticed. { No horn, 538. _Psilomelissa_. + ribs prolonged { + into three { Thorax with spongy framework, 539. _Spongomelissa_. + lateral wings. { + { Thorax with three large + { lateral holes between + { the three ribs, 540. _Clathrocanium_. + + c. Three thoracic { + ribs completely { Peristome simple, smooth, 541. _Lamprodiscus_. + enclosed in the { + wall of the { Peristome with a corona of + flat thorax { spines, 542. _Lampromitra_. + ------------------------------------------------------------------------- + B. Three radial ribs enclosed in the wall of the thorax and connected + with the cephalic horn by three latticed vertical wings. + ------------------------------------------------------------------------- + a. Thorax { No frontal horn (four spines), 543. _Callimitra_. + completely { + latticed { With frontal horn (five + { spines), 544. _Clathromitra_. + + b. Thorax with three large lateral holes between + the three ribs. No frontal horn, 545. _Clathrocorys_. + ------------------------------------------------------------------------- + C. Three radial beams (or cortinar rods) perfectly free, not enclosed in + the wall of the thorax. + ------------------------------------------------------------------------- + Three beams outside the thorax, arising freely + from the collar stricture (no cephalic hole), 546. _Eucecryphalus_. + + Three beams inside the thorax. Cephalis with + a large apical hole, 547. _Amphiplecta_. + ------------------------------------------------------------------------- + D. Three radial terminal feet on the peristome (the three original + lateral ribs are lost). + ------------------------------------------------------------------------- + Feet solid, 548. _Lychnocanium_. + + Feet latticed, 549. _Lychnodictyum_. + ------------------------------------------------------------------------- + II. Subfamily Sethoperida. + Terminal mouth of the thorax closed by a lattice-plate. + -------------------- + Three divergent ribs (or cortinar rods) enclosed either in the wall + or in the cavity of the thorax. + ------------------------------------------------------------------------- + Three ribs enclosed in the lattice-wall of the + thorax, 550. _Sethopera_. + + Three internal rods in the cavity of the thorax, 551. _Lithopera_. + ------------------------------------------------------------------------- + Three divergent free lateral wings (as prolongation of the three ribs) + on the sides of the thorax. + ------------------------------------------------------------------------- + Three solid { Cephalis with horn, 552. _Micromelissa_. + lateral spines. { + { No horn, 553. _Peromelissa_. + + Three latticed lateral wings. With horn, 554. _Sethomelissa_. + ------------------------------------------------------------------------- + Three free terminal feet (on the base of the thorax). + ------------------------------------------------------------------------- + Three feet solid, 555. _Tetrahedrina_. + + { Shell without external + Three feet { mantle, 556. _Sethochytris_. + latticed. { + { Shell with an arachnoidal + { mantle, 557. _Clathrolychnus_. + + + +{1195}Subfamily 1. SETHOPILIDA, Haeckel, 1881, Prodromus, p. 431. + +_Definition._--#Tripocyrtida#, with the basal mouth of the shell open (vel +Dicyrtida triradiata aperta). + + + +Genus 534. _Dictyophimus_,[151] Ehrenberg, 1847, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 53. + +_Definition._--#Sethopilida# (vel Dicyrtida triradiata aperta) with three +complete thoracic ribs, prolonged into three solid divergent feet on the +peristome. Cephalis with an apical horn. + +The genus _Dictyophimus_, comprising many common species, may be regarded +as the common ancestral form of all sethopilida, and therefore also of the +whole family of Dicyrtida. The cephalis bears an apical horn, and the +thorax three ribs, which are prolonged over the open mouth into three solid +feet. _Dictyophimus_ may be derived either from _Euscenium_ or _Peridium_ +(Archiperida), or from _Tripospyris_ (Zygospyrida), or from _Plectaniscus_ +(Plectanida), by development of lattice-work between the three terminal +feet, which therefore become thoracic ribs. + + + +Subgenus 1. _Dictyophimium_, Haeckel. + +_Definition._--Shell smooth or rough, without prominent spines on the edges +of the three thoracic ribs. (Commonly one single horn on the cephalis.) + + +1. _Dictyophimus sphaerocephalus_, n. sp. (Pl. 57, fig. 10). + +Shell smooth, with a deep collar stricture, separating two joints of nearly +equal size. Cephalis subglobular, rough, with a stout pyramidal horn of +half the length, and regular, circular, hexagonally framed pores. Thorax +nearly three-sided prismatic, smooth, with three stout, little divergent or +nearly parallel ribs, which are prolonged into conical subvertical feet +half as long. Thoracic pores irregular, roundish. + +_Dimensions._--Cephalis 0.08 long, 0.08 broad; thorax 0.08 long, 0.08 +broad. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +2. _Dictyophimus_ tripus, Haeckel. + + _Dictyophimus tripus_, Haeckel, 1862, Monogr. d. Radiol., p. 306, Taf. + vi. fig. 1. + +Shell with a slight collar stricture, separating two joints of slightly +different size. Cephalis nearly ellipsoidal, large, with a slender conical +horn of the same length. Thorax truncate three-sided {1196}pyramidal, with +three strongly divergent ribs, which are prolonged into three slender +conical feet of about the same length. Pores irregular, roundish, of +variable size. + +_Dimensions._--Cephalis 0.032 long, 0.028 broad; thorax 0.34 long, 0.064 +broad. + +_Habitat._--Mediterranean (Messina), Atlantic (Canary Islands), surface. + + +3. _Dictyophimus plectaniscus_, n. sp. (Pl. 61, figs. 8, 9). + +Shell flat, pyramidal, smooth, with distinct collar stricture. Cephalis +hemispherical, with a conical horn of the same length and numerous small +regular pores. Thorax flat, triangular, pyramidal, with three widely +divergent ribs, which are prolonged into three cylindrical feet of the same +length. Thoracic pores fifteen, very large, subregular, roundish, disposed +in two transverse girdles, the inner with six, the outer with nine pores; +five pores between every two ribs. + +_Dimensions._--Cephalis 0.04 long, 0.06 broad; thorax 0.08 long, 0.18 +broad. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +4. _Dictyophimus craticula_, Ehrenberg. + + _Dictyophimus craticula_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 68, Taf. v. figs. 4, 5. + + _Dictyophimus craticula_, Buetschli, 1882, Zeitschr. f. Wiss. Zool., vol. + xxxvi. p. 515, Taf. xxxiii. fig. 35. + +Shell flat, pyramidal, very similar to the preceding species, but differing +in the rudimentary horn, which is smaller than half the cephalis, and in +the length of the three cylindrical feet, which are twice to three times as +long as the shell. The nine inferior large pores of the thorax are twice to +three times as large as the six superior pores. The basal peristome is +commonly thorny. + +_Dimensions._--Cephalis 0.04 long, 0.05 broad; thorax 0.1 long, 0.2 broad. + +_Habitat._--Fossil in Barbados. + + +5. _Dictyophimus pyramis_, n. sp. (Pl. 61, fig. 16). + +Shell regular, pyramidal, with flat collar stricture. Relative length of +the two joints = 1 : 4, breadth = 2 : 6. Cephalis hemispherical, with a +stout pyramidal horn of the same length. Thorax triangular pyramidal, with +three prominent ribs, which are prolonged into three slender pyramidal +feet, half as long. Pores small and very numerous, subregular, circular. + +_Dimensions._--Cephalis 0.03 long, 0.05 broad; thorax 0.1 long, 0.15 broad. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +6. _Dictyophimus challengeri_, Haeckel. + + _Dictyophimus challengeri_, Haeckel, 1878, Protistenreich, p. 47, fig. + 35. + +Shell campanulate, with sharp collar stricture. Relative length of the +joints = 1 : 3, breadth = 1 : 4. Cephalis subspherical, with a stout +pyramidal horn of twice the length, and numerous {1197}very small pores. +Thorax nearly hemispherical, with three vaulted bosoms between the three +decurrent ribs, which are prolonged into three nearly parallel and vertical +feet of about the same length. Pores subregular, circular, of medium size. +This species is very similar to _Lychnodictyum challengeri_, Haeckel, but +differs in the smaller straight horn and the longer solid feet, which are +not fenestrated. + +_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.09 long, 0.13 +broad. + +_Habitat._--Tropical Atlantic, Station 347, surface. + + +7. _Dictyophimus lasanum_, n. sp. (Pl. 61, fig. 5). + +Shell nearly pear-shaped, with distinct collar stricture. Relative length +of the two joints = 1 : 3, breadth = 1 : 3. Cephalis hemispherical, with a +conical horn of the same length. Thorax nearly spherical, on both poles +truncate and constricted, with three decurrent curved ribs and small +regular circular pores. The prolongations of the ribs form three divergent +pyramidal straight feet, nearly as long as the thorax. + +_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.09 long, 0.09 +broad. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +8. _Dictyophimus longipes_, n. sp. (Pl. 61, fig. 3). + +Shell three-sided pyramidal, with distinct collar stricture. Relative +length of the two joints = 1 : 4, breadth = 2 : 6. Cephalis hemispherical, +with a rudimentary pyramidal horn, scarcely one-fourth as long; and with +small circular regular pores. Thorax with larger irregular pores, and three +vaulted bosoms between the three decurrent ribs, which are prolonged into +three very long and slender prismatic feet, S-shaped, curved, and twice to +three times as long as the shell. + +_Dimensions._--Cephalis 0.02 long, 0.04 broad; thorax 0.09 long, 0.13 +broad. + +_Habitat._--South Pacific, Station 300, depth 1375 fathoms. + + +9. _Dictyophimus gracilipes_, Bailey. + + _Dictyophimus gracilipes_, Bailey, 1856, Amer. Journ. Sci. and Arts, vol. + xxii. p. 4, pl. i. fig. 8. + +Shell three-sided pyramidal, with a deep collar stricture. Relative length +of the two joints = 1 : 3, breadth = 1 : 4. Cephalis hemispherical, with a +thin horn of the same length. Thorax with three curved ribs, which are +prolonged into three divergent angular feet of the same length. Pores +irregular roundish. + +_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.05 long, 0.08 +broad. + +_Habitat._--North Pacific, Station 240, surface, Kamtschatka (Bailey). + + +10. _Dictyophimus cortina_, n. sp. (Pl. 61, fig. 1). + +Shell three-sided pyramidal, with distinct collar stricture. Relative +length of the two joints = 1 : 3, breadth = 1 : 4. Cephalis subspherical, +with a pyramidal horn of half the length. Thorax {1198}with much larger +irregular roundish pores and three prominent ribs, which are prolonged into +three stout, club-shaped, strongly divergent feet of the same length. Mouth +widely open, elegantly coronate, with a circle of numerous small cilia. + +_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.06 long, 0.08 +broad. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +11. _Dictyophimus arabicus_, Haeckel. + + _Lychnocanium arabicum_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 296, Taf. x. fig. 3. + +Shell smooth, three-sided pyramidal, with deep collar stricture. Relative +length of the two joints = 1 : 3, breadth = 1 : 4. Cephalis subspherical, +with a slender horn of the same length. Thorax with much larger, irregular +roundish pores, and three widely divergent ribs, which are prolonged into +three slender, somewhat recurved feet of about the same length. + +_Dimensions._--Cephalis 0.02 long, 0.02 broad; thorax 0.07 long, 0.09 +broad. + +_Habitat._--Indian Ocean, Zanzibar (Pullen), depth 2200 fathoms. + + +12. _Dictyophimus platycephalus_, n. sp. (Pl. 60, figs. 4, 5). + +Shell smooth, flat, three-sided pyramidal, with distinct collar stricture. +Relative length of the two joints = 1 : 3, breadth = 3 : 9. Cephalis flat, +cap-shaped, three times as broad as long, with a slender conical horn of +the same length. Thorax flatly vaulted, with much larger, irregular +roundish, double-edged pores, and three widely divergent ribs, which are +prolonged into three slender conical feet of the same length. Central +capsule in the cephalis flat, discoidal, with a discoidal nucleus of half +the size, and with four large pear-shaped caecal sacs depending into the +thorax, each of which contains a large oil globule (fig. 4). + +_Dimensions._--Cephalis 0.02 long, 0.07 broad; thorax 0.06 long, 0.18 +broad. + +_Habitat._--North Atlantic, Canary Islands (Lanzerote), Haeckel, surface. + + +13. _Dictyophimus brandtii_, n. sp. (Pl. 60, fig. 6). + +Shell smooth, flat, three-sided pyramidal, with deep collar stricture, very +similar to the preceding species. Relative length of the two joints = +1 : 3, breadth = 2 : 7. Cephalis hemispherical, with a slender conical horn +of twice the length. Thorax flatly vaulted, with irregular polygonal pores +and thin bars; and with three widely divergent ribs, which are prolonged +into three slender prismatic feet of thrice the length. In fig. 6 the shell +is seen from the base and exhibits very distinctly the collar septum with +its four large meshes, two minor jugular and two major cardinal pores. + +_Dimensions._--Cephalis 0.03 long, 0.07 broad; thorax 0.08 long, 0.2 broad. + +_Habitat._--North Pacific, Station 236, surface. + + +{1199}14. _Dictyophimus lucerna_, Haeckel. + + _Lychnocanium lucerna_, Ehrenberg, 1854, Mikrogeol., Taf. xxxvi. fig. 6; + Abhandl. d. k. Akad. d. Wiss. Berlin, 1875, p. 80, Taf. viii. fig. 3. + + _Lychnocanium lucerna_, Haeckel, 1862, Monogr. d. Radiol., p. 311. + +Shell smooth, three-sided pyramidal, with slight collar stricture. Relative +length of the two joints = 1 : 4, breadth = 1 : 4. Cephalis hemispherical, +with a thick conical horn of twice the length. Thorax with small regular, +circular pores and three flat sides; between these arise three rounded +ribs, which are prolonged into three short, conical, divergent feet, +one-third as long as the thorax. + +_Dimensions._--Cephalis 0.02 long, 0.025 broad; thorax 0.08 long, 0.08 +broad. + +_Habitat._--Fossil in Barbados. + + +15. _Dictyophimus hamosus_, Haeckel. + + _Lychnocanium hamosum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 78, Taf. vii. fig. 9. + +Shell pear-shaped, rough, with deep collar stricture. Relative length of +the two joints = 1 : 2, breadth = 1 : 3. Cephalis subglobular, with a +conical horn of twice the length. Thorax with small, regular, circular +pores, and with three prominent ribs, prolonged into three vertical +prismatic feet, which are about as long as the shell, parallel or a little +convergent towards the distal end, with recurved teeth or hooks at the +lateral edges. + +_Dimensions._--Cephalis 0.02 long, 0.02 broad; thorax 0.04 long, 0.06 +broad. + +_Habitat._--Fossil in Barbados. + + +16. _Dictyophimus tridentatus_, Haeckel. + + _Lychnocanium tridentatum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 80, Taf. vii. fig. 4. + +Shell smooth, three-sided pyramidal, with deep collar stricture. Relative +length of the two joints = 1 : 3, breadth = 1 : 4. Cephalis subspherical, +with a conical horn of the same length, and some small accessory thorns. +Thorax tetrahedral, with three smooth hyaline walls, bearing only a single +series of small pores on each side of the three prominent ribs, which are +prolonged into three strong prismatic curved feet of twice the length, with +the convexity external. A group of small pores and a strong triangular +tooth at the base of each foot. + +_Dimensions._--Cephalis 0.02 long, 0.02 broad; thorax 0.06 long, 0.08 +broad. + +_Habitat._--Fossil in Barbados. + + + +Subgenus 2. _Lamprotripus_, Haeckel, 1881, Prodromus, p. 432. + +_Definition._--Shell spiny or thorny, with prominent spines on the edges of +the three thoracic ribs. (Commonly one larger and a few smaller horns or +spines on the cephalis.) + + +{1200}17. _Dictyophimus triserratus_, n. sp. (Pl. 61, fig. 17). + +Shell three-sided pyramidal, with slight collar stricture. Relative length +of the two joints = 1 : 3, breadth = 1 : 4. Cephalis small, subspherical, +with a large pyramidal horn three times as long. Thorax with much larger, +irregular roundish, double-edged pores, and three prominent, serrate ribs, +which are prolonged into three pyramidal strongly divergent feet of the +same length. + +_Dimensions._--Cephalis 0.02 long, 0.02 broad; thorax 0.06 long, 0.09 +broad. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + +18. _Dictyophimus bicornis_, n. sp. + +Shell thorny, with deep collar stricture. Relative length of the two joints += 2 : 3, breadth = 2 : 3. Cephalis nearly as large as the thorax, +subglobular, with numerous small, circular pores, and two divergent +pyramidal horns of half the length (a major occipital and a minor frontal +horn). Thorax three-sided pyramidal, with larger irregular pores and three +serrate ribs, which are prolonged into three prismatic spiny feet of half +the length. (Differs from the similar _Dictyophimus sphaerocephalus_, Pl. +57, fig. 10, mainly in the double horn and the spinulate feet.) + +_Dimensions._--Cephalis 0.05 long, 0.05 broad; thorax 0.08 long, 0.07 +broad. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +19. _Dictyophimus pocillum_, Ehrenberg. + + _Dictyophimus pocillum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 68, Taf. v. fig. 6. + +Shell thorny, with distinct collar stricture. Relative length of the two +joints = 1 : 5, breadth = 1 : 5. Cephalis nearly spherical, with numerous +small conical spines. Thorax flat, three-sided pyramidal with large, +irregular, roundish pores, and three strong, widely divergent, spinulate +ribs, which are prolonged into three prismatic spinulate feet of the same +length. + +_Dimensions._--Cephalis 0.03 long, 0.03 broad; thorax 0.15 long, 0.15 +broad. + +_Habitat._--Fossil in Barbados. + + +20. _Dictyophimus cienkowskii_, n. sp. (Pl. 60, fig. 1). + + _Lamprotripus squarrosus_, Haeckel, 1881, Prodromus et Atlas. + +Shell spiny, flatly pyramidal, with slight collar stricture. Relative +length of the two joints = 1 : 3, breadth = 2 : 6. Cephalis flat, +cap-shaped, three times as long as broad, with numerous bristle-shaped +spines three times as long. Thorax also spiny, with irregular, very large, +polygonal meshes and thin bars; its three ribs prolonged into three very +long and thin, widely divergent, prismatic feet, bearing numerous long +spines on the three edges. + +_Dimensions._--Cephalis 0.025 long, 0.05 broad; thorax 0.075 long, 0.15 +broad. + +_Habitat._--North Pacific, Station 250, surface. + + +{1201}21. _Dictyophimus buetschlii_, n. sp. (Pl. 60, fig. 2). + + _Lamprotripus horridus_, Haeckel, 1881, Prodromus et Atlas. + +Shell spiny, flatly pyramidal, with deep collar stricture. Relative length +at the two joints = 1 : 2, breadth = 1 : 5. Cephalis subspherical, with +numerous long, bristle-shaped spines and a larger ramified horn. Thorax +also spiny, flatly vaulted, with large, subregular, hexagonal meshes and +thin bars; its three spiny ribs prolonged into three very long and thin, +prismatic, widely divergent feet, twice to four times as long as the +thorax. + +_Dimensions._--Cephalis 0.04 long, 0.04 broad; thorax 0.08 long, 0.2 broad. + +_Habitat._--South Pacific, Station 284, surface. + + +22. _Dictyophimus hertwigii_, n. sp. (Pl. 60, fig. 3). + + _Lamprotripus spinosus_, Haeckel, 1881, Prodromus et Atlas. + +Shell spiny, flatly pyramidal with sharp collar stricture. Relative length +of the two joints = 1 : 2, breath = 1 : 5. Cephalis subspherical, with +irregular roundish pores, numerous small spines and a large, oblique, +prismatic horn of the same length, bearing on its distal end a bunch of +small divergent spines. Thorax pyramidal, with larger irregular polygonal +pores and thin bars; its three strong, widely divergent ribs spiny, +straight, and prolonged into three prismatic slender feet of the same +length. Central capsule with three lobes depending into the thorax. + +_Dimensions._--Cephalis 0.04 long, 0.04 broad; thorax 0.08 long, 0.2 broad. + +_Habitat._--Central Pacific, Stations 270 to 274, surface. + + + +Genus 535. _Tripocyrtis_,[152] n. gen. + +_Definition._--#Sethopilida# (vel Dicyrtida triradiata aperta) with three +complete thoracic ribs, prolonged into three latticed divergent feet on the +peristome. Cephalis with an apical horn. + +The genus _Tripocyrtis_ has been derived from the preceding _Dictyophimus_ +by complete fenestration of the three basal feet, which throughout their +whole length become united by complete lattice-work. This genus is closely +allied to _Plectaniscus_. + + +1. _Tripocyrtis plagoniscus_, n. sp. (Pl. 60, fig. 10). + +Cephalis subspherical, with large, roundish meshes and a stout, three-sided +pyramidal, irregularly branched horn of twice the length. Thorax with a +small number of large, irregular, polygonal meshes and three stout curved +ribs about as long as the cephalic horn. + +_Dimensions._--Cephalis 0.06 long, 0.07 broad; thorax 0.11 long, 0.16 +broad. + +_Habitat._--Central Pacific, Station 266, surface. + + +{1202}2. _Tripocyrtis tripodiscus_, n. sp. + +Cephalis subspherical, with small, polygonal pores and a large, +arborescent, vertical horn of thrice the length, bearing numerous ramified +branches. Thorax with three straight, widely divergent ribs, of the same +length as the horn, connected by a delicate, arachnoidal framework with +irregular, polygonal meshes. + +_Dimensions._--Cephalis 0.04 long, 05 broad; thorax 0.12 long, 0.18 broad. + +_Habitat._--Central Pacific, Station 269, surface. + + +3. _Tripocyrtis plectaniscus_, n. sp. (Pl. 60, fig. 9). + +Cephalis subspherical, with small roundish pores, and a stout, three-sided +pyramidal, denticulate horn of the same length. Thorax with three little +divergent and curved ribs, twice as long as the horn, in the upper half +with smaller, in the lower half with larger, polygonal, irregular meshes. + +_Dimensions._--Cephalis 0.05 long, 0.06 broad; thorax 0.1 long, 0.12 broad. + +_Habitat._--Central Pacific, Station 264, surface. + + + +Genus 536. _Sethopilium_,[153] Haeckel, 1881, Prodromus, p. 431. + +_Definition._--#Sethopilida# (vel Dicyrtida triradiata aperta) with three +complete thoracic ribs, which are prolonged into three solid divergent feet +on the peristome. Cephalis smooth, without a horn. + +The genus _Sethopilium_ differs from its probable ancestral form +_Dictyophimus_ by the complete loss of the cephalic horn, and of the collar +septum between both joints, which are only separated by the slight external +collar stricture. + + +1. _Sethopilium orthopus_, n. sp. (Pl. 97, fig. 8). + +Shell smooth, with sharp collar stricture, Relative length of the two +joints = 5 : 4, breadth = 7 : 6. Cephalis large, subspherical, with +numerous regular circular pores, twice as broad as the bars. Thorax with +three stout, straight, widely divergent ribs, prolonged into three straight +pointed feet of the same length. Between every two ribs, in the centre of +the collar stricture, a single large triangular mesh, and beyond this three +to six rows of smaller irregular meshes. + +_Dimensions._--Cephalis 0.05 long, 0.07 broad; thorax 0.04 long, 0.06 +broad. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +2. _Sethopilium cyrtopus_, n. sp. + +Shell smooth, with sharp collar stricture. Relative length of the two +joints = 4 : 6, breadth = 7 : 11. Cephalis hemispherical, with large +irregular roundish pores, four times as broad as the bars. {1203}Thorax +with three stout, curved, widely divergent ribs, prolonged into three +cylindro-conical, curved feet of twice the length, which are convex in the +proximal half, concave in the distal half. Between every two ribs, beyond +the collar stricture, two large ovate meshes, and beyond this two rows of +smaller irregular meshes. + +_Dimensions._--Cephalis 0.04 long, 0.07 broad; thorax 0.05 long, 0.11 +broad. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +3. _Sethopilium macropus_, n. sp. (Pl. 97, fig. 9). + +Shell smooth, with slight collar stricture. Relative length of the two +joints = 4 : 7, breadth = 6 : 13. Cephalis hemispherical, with irregular +double-contoured pores, about as broad as the bars. Thorax with three very +stout, carved, widely divergent ribs, prolonged into three curved, +cylindrical, very long feet, which are three to four times as long as the +shell, and convex on the outside. Between every two ribs, beyond the collar +stricture, two large broad meshes, and beyond this two or three rows of +smaller meshes. + +_Dimensions._--Cephalis 0.04 long, 0.06 broad; thorax 0.07 long, 0.13 +broad. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +Genus 537. _Lithomelissa_,[154] Ehrenberg, 1847, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 54. + +_Definition._--#Sethopilida# (vel Dicyrtida triradiata aperta) with three +free lateral wings, or solid spines arising from the sides of the thorax. +No terminal feet. Cephalis with one or more horns. + +The genus _Lithomelissa_, containing numerous and widely distributed forms, +may like _Dictyophimus_ be regarded as one of the most primitive and +ancient forms of Dicyrtida. It differs from the latter by the lateral (not +terminal) position of the three thoracic feet, and may be derived either +from _Dictyophimus_ (by secondary development of intrapedal network towards +the mouth, on the inside of the three feet) or directly from _Tripospyris_ +by similar formation of thoracic network beyond the collar stricture, +outside the base of the three divergent feet and pierced by the latter. As +the species of this genus are numerous, it may perhaps be better to divide +it into two or three genera: _Acromelissa_, with a single horn, +_Micromelissa_, with two horns, and _Sethomelissa_, with three or more +horns. + + + +Subgenus 1. _Acromelissa_, Haeckel, 1881, Prodromus, p. 431. + +_Definition._--Cephalis with a single occipital horn. + + +{1204}1. _Lithomelissa macroptera_, Ehrenberg. + + _Lithomelissa macroptera_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 78, Taf. iii. figs. 9, 10. + +Shell smooth, with distinct collar stricture. Relative length of the two +joints = 4 : 5, breadth = 3 : 4. Cephalis ovate, with a stout, excentric, +vertical, pyramidal horn of the same length. Thorax little larger, ovate, +truncate. Both joints with very small and scattered pores. Three divergent +ribs arise from the base of the cephalic horn, and are prolonged over the +major part of the thorax; their under free part arises from the middle part +of the thorax and is as long as the horn, straight, pyramidal. Mouth +truncate, little constricted. + +_Dimensions._--Cephalis 0.04 long, 0.03 broad; thorax 0.05 long, 0.04 +broad. + +_Habitat._--Fossil in Barbados. + + +2. _Lithomelissa ehrenbergii_, Buetschli. + + _Lithomelissa ehrenbergii_, Buetschli, 1882, Zeitschr. f. wiss. Zool., + vol. xxxvi. p. 517, Taf. xxxiii. fig. 21_a_, _b_. + + _Lithomelissa macroptera_, var., Ehrenberg, 1875, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 78, Taf. iii. fig. 8. + + (?) _Lophophaena capito_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 78, Taf. viii. fig. 6. + + (?) _Lophophaena galeata_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 78, Taf. viii. fig. 12. + +Shell rough, with distinct collar stricture. Relative length of the two +joints = 4 : 2, breadth = 3 : 4. Cephalis ovate, with a stout excentric, +oblique, pyramidal horn of half the length. Thorax little shorter, +truncate, conical. Both joints with regular circular pores, of the same +breadth as the bars. Three divergent conical feet, as long as the cephalis, +arise below the collar stricture. Mouth truncate, not constricted. + +_Dimensions._--Cephalis 0.08 long, 0.06 broad; thorax 0.04 long, 0.08 +broad. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms; fossil in +Barbados. + + +3. _Lithomelissa macroceras_, n. sp. + +Shell spiny, with sharp collar stricture. Relative length of the two joints += 5 : 7, breadth = 5 : 6. Cephalis spherical, with a large pyramidal horn +of twice the length. Thorax little longer, ovate, truncate. Both joints +with regular circular pores, three times as broad as the bars. Three +divergent pyramidal feet, twice as long as the cephalis, arise from the +middle part of the thorax. Mouth constricted, half as broad as the thorax. + +_Dimensions._--Cephalis 0.05 long, 0.05 broad; thorax 0.07 long, 0.06 +broad. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +4. _Lithomelissa mitra_, Buetschli. + + _Lithomelissa mitra_, Buetschli, 1881, Zeitschr. f. wiss. Zool., p. 518, + Taf. xxxiii. fig. 24. + +Shell smooth, with distinct collar stricture. Relative length of the two +joints = 5 : 4, breadth = 4 : 5. Cephalis ovate, with a slender, straight, +vertical, pyramidal horn of the same length. Thorax ovate, {1205}truncate, +of about the same size. Both joints with very small and numerous pores, as +broad as the bars. Three feet arising from the middle part of the thorax, +very small, rudimentary, pyramidal, about as long as broad. Mouth truncate, +little constricted. + +_Dimensions._--Cephalis 0.05 long, 0.04 broad; thorax 0.04 long, 0.05 +broad. + +_Habitat._--Fossil in Barbados. + + +5. _Lithomelissa pycnoptera_, n. sp. + +Shell rough, papillate, with slight collar stricture. Relative length of +the two joints = 1 : 3, breadth = 1 : 3. Cephalis small, hemispherical, +with very small pores and a slender, straight, conical horn of twice the +length. Thorax subconical, with regular circular, hexagonally framed pores, +as broad as the bars. From its lower half arise three divergent, very +strong feet, pyramidal, as long as the thorax, and three times as long as +broad. + +_Dimensions._--Cephalis 0.03 diameter, thorax 0.1 diameter. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +6. _Lithomelissa microstoma_, n. sp. + +Shell papillate, with slight collar stricture. Relative length of the two +joints = 1 : 5, breadth = 1 : 5. Cephalis small, hemispherical, with a +conical horn of twice the length. Thorax subspherical, with subregular +circular pores, three times as broad as the bars. From its middle part +arise three divergent, stout, conical feet, of half the length, and twice +as long as broad. Mouth small, strongly constricted, one-fourth to +one-third as broad as the thorax. + +_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.15 diameter. + +_Habitat._--Fossil in Barbados. + + +7. _Lithomelissa amphora_, Stoehr. + + _Lithomelissa amphora_, Stoehr, 1880, Palaeontograph, vol. xxvi. p. 100, + Taf. iii. fig. 11. + +Shell smooth, with sharp collar stricture. Relative length of the two +joints = 1 : 5, breadth = 2 : 4. Cephalis small, hemispherical, with a +cervical horn of the same length. Thorax ovate, with small regular circular +pores, twice as broad as the bars. From its upper half arise three +divergent, slender, conical feet, only one-fourth as long. Mouth +constricted, with a hyaline peristome, half as broad as the thorax. + +_Dimensions._--Cephalis 0.013 long, 0.026 broad; thorax 0.063 long, 0.053 +broad. + +_Habitat._--Fossil in tertiary rocks of Sicily; Grotte (Stoehr). + + + +Subgenus 2. _Micromelissa_, Haeckel, 1881, Prodromus, p. 433 (_sensu +emendato_). + +_Definition._--Cephalis with two divergent horns, a superior occipital horn +and an inferior frontal horn. + + +{1206}8. _Lithomelissa thoracites_, Haeckel. + + _Lithomelissa thoracites_, Haeckel, 1862, Monogr. d. Radiol., p. 301, + Taf. vi. figs. 2-8. + + _Lithomelissa thoracites_, R. Hertwig, 1879, Organism. d. Radiol., p. 76, + Taf. viii. fig. 1. + +Shell smooth, with deep collar stricture. Cephalis ovate, with two +divergent, slender, conical horns, of about half the length; a major +oblique occipital horn on the posterior face, and a minor, nearly +horizontal horn above the collar stricture, on the anterior face. Thorax +about as large as the cephalis, truncate, ovate. Pores of both joints +irregular, roundish, of different sizes. From the upper half of the thorax, +below the collar stricture, there arise three slender, conical divergent +feet, about as long as the cephalis. Mouth truncate, wide open, not +constricted. On the numerous varieties of this common species compare my +Monograph, on the structure of the ovate central capsule (enclosed in the +cephalis), Hertwig, _loc. cit._ + +_Dimensions._--Cephalis 0.05 to 0.08 long, 0.04 broad; thorax 0.03 to 0.05 +long, 0.05 to 0.07 broad. + +_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Indian, Pacific, +surface. + + +9. _Lithomelissa mediterranea_, J. Mueller. + + _Lithomelissa mediterranea_, J. Mueller, 1858, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 45, Taf. vi. fig. 11. + + _Lithomelissa mediterranea_, Haeckel, 1862, Monogr. d. Radiol., p. 302. + +Shell smooth, with sharp collar stricture. Relative length of the two +joints = 4 : 5, breadth = 4 : 5. Cephalis campanulate, conical, with two +divergent small conical horns, a major occipital subvertical horn near the +summit, and a minor sub-horizontal frontal horn near the collar stricture. +Thorax truncate, ovate, little larger than the cephalis. From its lower +part there arise three short conical, divergent feet, scarcely half as long +as the cephalis (in Mueller's figure one of them is seen shortened, +opposite to the frontal horn). Pores irregular, roundish, much smaller in +the cephalis than in the thorax. Mouth wide open, not constricted. + +_Dimensions._--Cephalis 0.04 diameter, thorax 0.05 diameter. + +_Habitat._--Mediterranean (French shore), J. Mueller, surface. + + +10. _Lithomelissa bicornis_, Ehrenberg. + + _Lithomelissa bicornis_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 297, Taf. ii. fig. 7. + +Shell smooth, with deep collar stricture. Relative length of the two joints += 1 : 3, breadth = 1 : 2. Cephalis hemispherical, with two divergent, stout +and straight, pyramidal horns; a larger occipital horn sub-vertical near +the summit, and a smaller oblique frontal horn near the collar stricture. +Thorax subspherical, twice as large, with larger irregular, roundish pores. +From its lower half there arise three divergent curved pyramidal feet of +about the same length. Mouth constricted, only one-third as broad as the +thorax. + +_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.06 diameter. + +_Habitat._--Atlantic, Stations 348 to 353, surface. + + +{1207}11. _Lithomelissa haeckelii_, Buetschli. + + _Lithomelissa haeckelii_, Buetschli, 1883, Zeitschr. f. wiss. Zool., vol. + xxxvi. p. 517, Taf. xxxiii. fig. 23, a, b. + +Shell rough, with sharp collar stricture. Relative length of the two joints += 6 : 5, breadth = 6 : 7. Cephalis subspherical, large, with two divergent +horns, a very large, oblique pyramidal occipital horn on the summit, and a +very small frontal horn on the middle of the forehead. Thorax campanulate, +little larger than the cephalis, with regular circular pores of twice the +breadth. From the upper part of the thorax, below the collar stricture, +there arise three stout, divergent, angular, semi-lunar feet, about as long +as the shell. Mouth wide open, not constricted. + +_Dimensions._--Cephalis 0.6 long, 0.6 broad; thorax 0.05 long, 0.07 broad. + +_Habitat._--Tropical Atlantic, Station 347, depth 2260 fathoms; fossil in +Barbados. + + +12. _Lithomelissa buetschlii_, n. sp. (Pl. 56, fig. 1). + +Shell smooth, with slight collar stricture. Relative length of the two +joints = 5 : 6, breadth = 4 : 5. Cephalis ovate, large, with two small +conical horns, which are opposed nearly horizontally, in the upper part of +the cephalis; an anterior frontal and a posterior occipital horn. Thorax +ovate, truncate, little larger. Pores of both joints irregular, roundish, +of very different sizes. From the middle part of the thorax there arise +three short conical divergent feet. (In the figured specimen there were +some accessory thorns; in another specimen, found afterwards, the surface +was quite smooth, but the two horns and the three feet much larger, half as +long as the cephalis.) + +_Dimensions._--Cephalis 0.05 long, 0.04 broad; 0.06 long, 0.05 broad. + +_Habitat._--Central Pacific, Stations 266 to 274, depth 2350 to 2925 +fathoms. + + + +Subgenus 3. _Sethomelissa_, Haeckel, 1881, Prodromus, p. 431. + +_Definition._--Cephalis with three, four, or more horns, a primary +occipital, a secondary frontal, and one or more accessory parietal horns. + + +13. _Lithomelissa corythium_, Ehrenberg. + + _Lithomelissa corythium_, Ehrenberg, 1875, Abhandl. d.k. Akad. d. Wiss. + Berlin, p. 78, Taf. iii, fig. 12. + +Shell smooth, with slight collar stricture. Relative length of the two +joints = 4 : 3, breadth = 4 : 5. Cephalis campanulate, with three short +conical horns on the summit. Thorax flat and wide. From its upper part +below the collar stricture, there arise three divergent, pyramidal feet, +fenestrated at the base, about as long as the shell. Mouth wide open. (The +specimen figured by Ehrenberg was an incomplete one.) + +_Dimensions._--Cephalis 0.04 in diameter, thorax 0.03 long, 0.05 broad. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms; fossil in +Barbados. + + +{1208}14. _Lithomelissa decacantha_, n. sp. (Pl. 56, fig. 2). + + _Sethomelissa decacantha_, Haeckel, 1881, Prodromus et Atlas. + +Shell smooth, with deep collar stricture, and with ten prismatic spines of +nearly equal size and similar form. Relative length and breadth of the two +joints about equal. Cephalis ovate, in the upper half hyaline, in the lower +half with few scattered pores; in the equator with four prismatic horns of +the same length, which diverge upwards; three of them are placed in the +same meridional planes as the three wings and the three feet of the thorax +(one occipital and two parietal); the fourth (frontal) horn is opposed to +the occipital. Thorax campanulate, three-edged, with three vertical +prominent feet (directed downward) and three horizontal wings, arising from +their knees. Mouth wide open, not constricted. + +_Dimensions._--Cephalis 0.05 diameter; thorax 0.05 long, 0.06 broad. + +_Habitat._--Equatorial Atlantic, Station 347, surface. + + + +Genus 538. _Psilomelissa_,[155] Haeckel, 1881, Prodromus, p. 431. + +_Definition._--#Sethopilida# (vel Dicyrtida triradiata aperta) with three +free lateral wings, or solid spines arising from the sides of the thorax. +No terminal feet. Cephalis smooth, without a horn. + +The genus _Psilomelissa_ has the same formation of the shell as the nearly +allied preceding genus _Lithomelissa_, and may be derived from it by +reduction and loss of the cephalic horn. The cephalis is quite bare. + + +1. _Psilomelissa galeata_, Haeckel. + + _Dictyocephalus galeatus_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 289, Taf. vii. fig. 25. + +Shell smooth, with sharp collar stricture. Relative length of the two +joints = 5 : 3, breadth = 4 : 5. Cephalis ovate, with numerous irregular, +roundish pores. Thorax truncate, conical, with a few small pores. From its +upper part (below the collar stricture) there arise three thin, +bristle-shaped, widely divergent wings, about as long as the cephalis. +Mouth widely open. + +_Dimensions._--Cephalis 0.05 long, 0.04 broad; thorax 0.03 long, 0.05 +broad. + +_Habitat._--Western Tropical Pacific, Stations 200 to 225, surface. + + +2. _Psilomelissa phalacra_, n. sp. + +Shell smooth, with deep collar stricture. Relative length of the two joints += 5 : 6, breadth = 4 : 4. Cephalis ovate, hyaline, with few small pores +only in the lower third. Thorax cylindrical, truncate, with small +irregular, roundish pores. From its upper third there arise below the +stricture three {1209}club-shaped, nearly horizontally divergent wings, as +long as the thorax. The cephalis and the three feet are similar to those of +_Peromelissa phalacra_, (Pl. 57, fig. 11); but the cylindrical thorax with +irregularly scattered pores is completely different, and exhibits a +truncate, wide open mouth. + +_Dimensions._--Cephalis 0.05 long, 0.04 broad; thorax 0.06 long, 0.04 +broad. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +3. _Psilomelissa hertwigii_, Haeckel. + + _Lithomelissa hertwigii_, Buetschli, 1882, Zeitschr. f. wiss. Zool., p. + 517, Taf xxxiii. fig. 22, _a_, _b_. + +Shell rough, with obliterated collar stricture. Length of the two joints = +4 : 4, breadth = 5 : 5. Cephalis hemispherical. Thorax little larger, +cylindrical. From its upper half there arise three very strong pyramidal +divergent wings, about as long as the shell. Pores of both joints very +small and numerous, circular. Mouth truncate, wide open. + +_Dimensions._--Cephalis 0.04 long, 0.06 broad; thorax 0.04 long, 0.05 +broad. + +_Habitat._--Fossil in Barbados. + + +4. _Psilomelissa calvata_, n. sp. (Pl. 56, fig. 3). + +Shell smooth, with sharp collar stricture. Length of the two joints = +7 : 5, breadth = 5 : 6. Cephalis ovate, large, with subregular, circular, +double-contoured pores. Thorax smaller, ovate, with very irregular, +roundish pores of different sizes. From its upper third there arise three +conical, slender, widely divergent spines or wings of the same length. (In +fig. 3 the cephalis with the three wings is alone represented.) + +_Dimensions._--Cephalis 0.07 long, 0.05 broad; thorax 0.05 long, 0.06 +broad. + +_Habitat._--Central Pacific, Stations 263 to 274, depth 2350 to 2925 +fathoms. + + +5. _Psilomelissa sphaerocephala_, n. sp. + +Shell rough, with deep collar stricture. Length of the two joints = 1 : 2, +breadth = 1 : 3. Cephalis spherical. Thorax cap-shaped, flat and broad. +From its upper half there arise three pyramidal wings, half as long, +fenestrated at the base and nearly horizontally divergent. Mouth +constricted, half as broad as the thorax. + +_Dimensions._--Cephalis 0.03 diameter; thorax 0.06 long, 0.09 broad. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + + +Genus 539. _Spongomelissa_,[156] n. gen. + +_Definition._--#Sethopilida# (vel Dicyrtida triradiata aperta) with three +free lateral wings, or solid spines arising from the sides of the thorax. +No terminal feet. Cephalis with one or more horns. + +{1210}The genus _Spongomelissa_ differs from its ancestral genus +_Lithomelissa_ only in the development of spongy framework in the +shell-wall--a very rare production in the #Cyrtoidea# (compare +_Peripyramis_, p. 1162, and _Spongocyrtis_, p. 1188). + + +1. _Spongomelissa spongiosa_, Haeckel. + + _Lithomelissa spongiosa_, Buetschli, 1882, Zeitschr. f. wiss. Zool., vol. + xxxvi. pp. 519, 539, Taf. xxxiii. fig. 25, _a_, _b_, _c_. + +Shell of dense spongy structure, with a deep collar stricture. The +subspherical cephalis and the truncate abdomen of nearly equal size, both +with irregular delicate spongy framework. Mouth wide open. Cephalis with a +large vertical apical and a small oblique frontal horn. Thorax with three +very stout, three-sided prismatic widely divergent lateral wings, which are +covered with numerous irregularly ramified branches; the spongy framework +arises by communication of the delicate branches. + +_Dimensions._--Cephalis 0.04 long, 0.05 broad; thorax 0.04 long, 0.06 +broad. + +_Habitat._--Fossil in Barbados. + + + +Genus 540. _Clathrocanium_,[157] Ehrenberg, 1860, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 829. + +_Definition._--#Sethopilida# (vel Dicyrtida triradiata aperta) with three +prominent lateral ribs on the thorax, alternating with three large holes +(or thoracic gates). Cephalis with a horn. + +The genus _Clathrocanium_ is nearly allied to _Dictyophimus_ and +_Lithomelissa_, and, together with these two genera, may be regarded as +surviving representatives of the oldest and most primitive forms of +Dicyrtida. It differs from the latter mainly in the incomplete fenestration +of the shell, three large interradial holes remaining between the three +perradial thoracic ribs. It may therefore be derived either from +_Euscenium_ or from _Tripospyris_ by the development of a terminal +lattice-band between the three feet. _Clathrocanium_ may be divided into +two different subgenera: _Clathrocanidium_, with simple horn and smooth +mouth, and _Clathrocorona_, with fenestrated horn and coronated mouth. + + + +Subgenus 1. _Clathrocanidium_, Haeckel. + +_Definition._--Horn of the cephalis simple, not fenestrated. Peristome +smooth. + + +{1211}1. _Clathrocanium squarrosum_, Ehrenberg. + + _Clathrocanium squarrosum_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 287, Taf. vii. fig. 5. + +Cephalis campanulate, with irregular roundish pores and a pyramidal horn of +the same length, bearing at the apex three short branches. Length of the +two joints 2 : 3, breadth = 2 : 6. Thorax with three simple, prismatic, +thin ribs, which are twice as long as the cephalis, separated by large +triangular holes and connected only at the distal end by a small triangular +ring of delicate lattice-work. Peristome smooth, wide, as broad as the +thorax. + +_Dimensions._--Cephalis 0.04 long, 0.04 broad; thorax 0.06 long, 0.12 +broad. + +_Habitat._--Western Tropical Pacific (Philippine Sea), depth 3300 fathoms. + + +2. _Clathrocanium sphaerocephalum_, n. sp. (Pl. 64, fig. 1). + +Cephalis spherical, with regular circular pores and a prismatic horn of the +same length, with three serrated edges. Length of the two joints = 2 : 3, +breadth 2 : 4. Thorax with three broad, triangular, latticed, divergent +ribs, which are separated by three large ovate holes (about as large as the +cephalis), and connected at the distal end by a broad fenestrated circular +ring of regular lattice-work (about six pores in its height). Peristome +smooth, constricted, half as broad as the thorax. + +_Dimensions._--Cephalis 0.04 long, 0.04 broad; thorax 0.06 long, 0.08 +broad. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +3. _Clathrocanium coarctatum_, Ehrenberg. + + _Clathrocanium coarctatum_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 287, Taf vii. fig. 6. + + _Lychnocanium fenestratum_, Ehrenberg, 1860, Monatsber. d. k. preuss. + Akad. d. Wiss. Berlin, p. 767. + +Cephalis spherical, thorny, with regular circular pores and a simple +pyramidal horn of the same length. Length of the two joints = 2 : 3, +breadth = 2 : 5. Thorax with three simple, prismatic, little prominent +ribs, which are separated by three large ovate holes (twice as long as the +cephalis), and connected below the prominent distal end by a narrow +circular ring of delicate lattice-work. Peristome smooth, wide, little +narrower than the thorax. + +_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.06 long, 0.1 broad. + +_Habitat._--Western Tropical Pacific (Philippine Sea), depth 3300 fathoms. + + +4. _Clathrocanium triomma_, n. sp. (Pl. 64, fig. 3). + +Cephalis spherical, thorny, with regular circular pores, and a slender +prismatic horn of twice the length, bearing at its apex three short +recurved branches. Length of the two joints = 2 : 4, breadth = 2 : 5. +Thorax with three broad prismatic, fenestrated ribs, which are separated by +three large {1212}subcircular holes, and below the prominent distal end by +a broad, triangular, roundish ring of subregular lattice-work (with square +pores). Peristome smooth, about half as broad as the thorax. + +_Dimensions._--Cephalis 0.04 long, 0.04 broad; thorax 0.08 long, 0.1 broad. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + + +Subgenus 2. _Clathrocorona_, Haeckel, 1881, Prodromus, p. 431. + +_Definition._--Horn of the cephalis fenestrated. Peristome on the margin of +the basal mouth with a corona of spines. + + +5. _Clathrocanium diadema_, n. sp. (Pl. 64, fig. 2). + + _Clathrocorona diadema_, Haeckel, 1881, Prodromus, p. 431. + +Cephalis hemispherical, thorny, with irregular roundish pores, and a large +prismatic horn of twice the length, the three edges of which are +denticulate and fenestrated, each with a series of square pores. Length of +the two joints = 1 : 3, breadth = 2 : 4. Thorax thorny, with three broad +fenestrated divergent ribs, which are separated by three large ovate holes +(twice as long as the cephalis) and have their prominent distal ends +connected below by a broad circular ring of lattice-work (with irregular +polygonal small meshes). Peristome wide, two-thirds as broad as the thorax, +with a circular corona of small square pores and alternating prominent +small teeth. + +_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.07 long, 0.09 +broad. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +6. _Clathrocanium reginae_, n. sp. (Pl. 64, fig. 4). + + _Clathrocorona reginae_, Haeckel, 1881, Prodromus, p. 431. + +Cephalis hemispherical, with irregular roundish pores and a prismatic +club-shaped horn of twice the length, the three edges of which are +denticulate and fenestrated. Length of the two joints = 1 : 3, breadth = +1 : 4. Thorax thorny, with three broad triangular, fenestrated and +nodulated ribs, which are separated by three large ovate holes (twice as +long as the cephalis) and have their prominent distal ends connected below +by a circular ring of lattice-work. Peristome constricted, as broad as the +thorax, with a corona of short spines. + +_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.08 long, 0.12 +broad. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + + +Genus 541. _Lamprodiscus_,[158] Ehrenberg, 1860, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 831. + +_Definition._--#Sethopilida# (vel Dicyrtida triradiata aperta) with three +divergent lateral ribs in the wall of the flat, conical, discoidal, or +pyramidal thorax. Cephalis with a horn. Peristome smooth, without corona of +spines. + +{1213}The genus _Lamprodiscus_, and the following nearly allied +_Lampromitra_, differ from all preceding Sethopilida in the complete +connection of the three thoracic feet by lattice-work, so that they are +imbedded in the thorax-wall as prominent ribs and are not prolonged beyond +the margin as free feet. The shell is commonly very flat, conical or +pyramidal, sometimes nearly discoidal. The margin of _Lamprodiscus_ is +simple, smooth. + + +1. _Lamprodiscus monoceros_, Ehrenberg. + + _Lamprodiscus monoceros_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 295, Taf. vii. fig. 2. + +Shell smooth, with deep collar stricture. Length of the two joints = 1 : 5, +breadth = 1 : 8. Cephalis spherical, hyaline, without pores, with an +oblique conical horn of the same length. Thorax flat, campanulate, nearly +hemispherical, with convex lateral outlines, and regular hexagonal meshes, +increasing gradually in size towards the mouth. Bars very thin. Peristome +smooth. + +_Dimensions._--Cephalis 0.02 diameter; thorax 0.1 long, 0.16 broad. + +_Habitat._--Western Tropical Pacific (Philippine Sea), Station 200, +surface. + + +2. _Lamprodiscus coscinodiscus_, Ehrenberg. + + _Lamprodiscus coscinodiscus_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 295, Taf. vii. fig. 3. + +Shell smooth, with sharp collar stricture. Thorax of the same form and +structure as in the preceding species, differing from it mainly in the +structure of the smooth circular margin, which is composed of a ring of +very small square pores. Length of the two joints = 1 : 4, breadth = 1 : 8. +Cephalis with small hexagonal pores, without horn or with a short +rudimentary horn. Lateral outlines of the campanulate thorax in the upper +part concave, in the lower convex. + +_Dimensions._--Cephalis 0.02 diameter; thorax 0.08 long, 0.16 broad. + +_Habitat._--Tropical Pacific, Stations 206, 224, 266, &c., surface. + + +3. _Lamprodiscus tricostatus_, n. sp. + +Shell smooth with deep collar stricture. Length of the two joints = 1 : 3, +breadth = 1 : 7. Cephalis spherical, with an oblique conical horn of twice +the length and small circular pores. Thorax flatly conical, twice as broad +as high, with straight lateral outline, and regular hexagonal meshes, +increasing gradually in size towards the mouth; bars very thin. Peristome +or margin of the basal mouth circular, smooth. Very similar to _Theopilium +tricostatum_ (Pl. 70, fig. 6), but without abdomen. Differs from the two +preceding species mainly in the conical form of the thorax and the less +delicate network. + +_Dimensions._--Cephalis 0.03 diameter; thorax 0.1 long, 0.2 broad. + +_Habitat._--Cosmopolitan, Mediterranean, Atlantic, Indian, Pacific; +surface. + + +{1214}4. _Lamprodiscus laevis_, Haeckel. + + _Eucecryphalus laevis_, R. Hertwig, 1879, Organism. d. Radiol., p. 77, + Taf. viii. figs. 6, 6_a_, 6_b._ + +Shell smooth, with distinct collar stricture. Length of the two joints = +1 : 3, breadth = 1 : 6. Cephalis subspherical, with small circular pores +and an oblique conical horn of twice the length. Thorax flat, pyramidal, +twice as broad as long, with three strong, straight divergent edges and +subregular roundish pores. Peristome smooth. + +_Dimensions._--Cephalis 0.025 diameter; thorax 0.08 long, 0.16 broad. + +_Habitat._--Mediterranean (Messina), R. Hertwig, surface. + + + +Genus 542. _Lampromitra_, Haeckel,[159] 1881, Prodromus, p. 431. + +_Definition._--#Sethopilida# (vel Dicyrtida triradiata aperta) with three +divergent lateral ribs in the wall of the flat conical or pyramidal thorax. +Cephalis commonly with a horn. Peristome with a corona of spines. + +The genus _Lampromitra_ differs from the preceding and nearly allied +_Lamprodiscus_ only in the development of a dentated peristome, or an +elegant corona of teeth around the wide open mouth. It bears therefore to +the latter the same relation that _Clathrocorona_ does to _Clathrocanium_. + + +1. _Lampromitra coronata_, n. sp. (Pl. 60, fig. 7, 7_a_). + +Shell flat, conical, with slight collar stricture. Length of the two joints += 1 : 2, breadth = 2 : 7. Cephalis hemispherical, with a conical oblique +horn of twice the length, and small subregular hexagonal pores. Thorax with +larger, subregular, hexagonal meshes, six to eight times as broad as the +bars. Peristome or basal margin of the thorax circular, with a marginal +ring of smaller polygonal meshes and a triple coronal of short spines; two +external rings of short conical centrifugal spines, and an internal ring of +thin centripetal rods (fig. 7_a_). In fig. 7 the shell is seen from below +and exhibits very distinctly the internal cross of the collar septum, +composed of the four divergent cortinar bars; between the latter descend +the four pear-shaped lobes of the central capsule (each containing an oil +globule), whilst the apical part of the capsule (with the nucleus) is +hidden in the large cap-shaped cephalis. + +_Dimensions._--Cephalis 0.03 long, 0.07 broad; thorax 0.06 long, 0.2 broad. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +2. _Lampromitra quadricuspis_ (Pl. 58, fig. 7). + +Shell flat, conical, with sharp collar stricture. Length of the two joints += 1 : 3, breadth = 2 : 10. Cephalis hemispherical, with subregular circular +pores and an oblique, conical, occipital horn of twice {1215}the length, +bearing three divergent lateral branches, which are directed upwards, and +correspond to the three thoracic ribs. Further down, near the collar +stricture, a short divergent frontal horn arises. Thorax with irregular +roundish pores of different sizes, three to six times as broad as the bars. +Peristome with a simple coronal of short, conical, divergent spines, about +as long as the diameter of the cephalis. + +_Dimensions._--Cephalis 0.02 long, 0.04 broad; thorax 0.06 long, 0.2 broad. + +_Habitat._--North Atlantic, Canary Islands, surface. + + +3. _Lampromitra furcata_, n. sp. (Pl. 58, fig. 8). + +Shell flat, conical, with deep collar stricture, very similar in form and +structure to the preceding species; differs from it in the shape of the +peristome and the armature of the cephalis, which bears a conical, forked, +occipital horn of the same length, and a small rudimentary divergent +frontal horn. Length of the two joints = 1 : 2, breadth = 1 : 6. The four +pores of the collar septum (two larger cardinal and two smaller jugular) +exhibit in this species a peculiar asymmetry (fig. 8). The peristome bears +a simple coronal of spines as long as the diameter of the cephalis. The +major part of them is forked, some irregularly branched. + +_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.06 long, 0.18 +broad. + +_Habitat._--South Pacific, Station 298, depth 2225 fathoms. + + +4. _Lampromitra pyramidalis_, n. sp. + +Shell flat, pyramidal, smooth, with slight collar stricture. Length of the +two joints = 1 : 4, breadth = 1 : 9. Cephalis subspherical, with an oblique +pyramidal horn of twice the length, and small circular pores. Thorax with +three strong, divergent, straight ribs and three flat triangular sides +between them, with subregular hexagonal pores, increasing in size towards +the mouth. Peristome with a simple coronal of large and numerous divergent, +conical spines, half as long as the shell. + +_Dimensions._--Cephalis 0.02 long, 0.02 broad; thorax 0.09 long, 0.18 +broad. + +_Habitat._--South Atlantic, Station 325, depth 2650 fathoms. + + +5. _Lampromitra huxleyi_, Haeckel (Pl. 59, fig. 1). + + _Eucecryphalus huxleyi_, Haeckel, 1879, Natuerl. Schoepfungsgesch., Edit. + vii. Taf. xvi. fig. 9. + +Shell flat, conical, spiny, with slight collar stricture. Length of the two +joints = 1 : 3, breadth = 1 : 8. Cephalis hemispherical, with a short +conical horn of the same length. Thorax with irregular polygonal pores. +Peristome with three coronals of divergent bristle-shaped spines; the first +directed obliquely upwards, the second outwards, and the third nearly +vertically, downwards; the bristles of the latter are much longer, about as +long as the height of the shell. + +_Dimensions._--Cephalis 0.02 long, 0.02 broad; thorax 0.06 long, 0.16 +broad. + +_Habitat._--Australia (east coast), Station 169, surface. + + +{1216}6. _Lampromitra schultzei_, Haeckel. + + _Eucecryphalus schultzei_, Haeckel, 1862, Monogr. d. Radiol., p. 309, + Taf. v. figs. 16-19. + +Shell flat, conical, smooth, with slight collar stricture. Length of the +two joints = 1 : 3, breadth = 1 : 8. Cephalis hemispherical, with a small +conical horn of half the length, and very small roundish pores. Thorax with +three strong, straight ribs and irregular polygonal pores, which are much +larger in the middle part than in the upper or lower part. Peristome with a +double coronal of short, conical, divergent spines; the superior obliquely +ascending, the inferior vertically descending. (Named in honour of the late +Professor Max Schultze, the illustrious histologist.) + +_Dimensions._--Cephalis 0.025 diameter; thorax 0.07 long, 0.2 broad. + +_Habitat._--Mediterranean, Messina, surface. + + +7. _Lampromitra arborescens_, n. sp, (Pl. 60, fig. 8, 8_a_). + +Shell flat, pyramidal, spiny, with sharp collar stricture. Length of the +two joints = 1 : 3, breadth = 2 : 10. Cephalis cap-shaped, with an oblique, +slender, conical horn of twice the length, and small circular pores. Thorax +with three slight almost obliterated ribs and three vaulted sides between +them, with irregular roundish pores. The three ribs are distinct in the +proximal, not in the distal part. Peristome with a double coronal of +smaller squarish pores and numerous divergent spines; the larger spines are +irregularly branched and as long as the diameter of the cephalis. + +_Dimensions._--Cephalis 0.15 long, 0.03 broad; thorax 0.04 long, 0.2 broad. + +_Habitat._--Indian Ocean, Madagascar (Rabbe), surface. + + +8. _Lampromitra dendrocorona_, n. sp. (Pl. 58, fig. 9). + +Shell flat, conical, with smooth surface and deep collar stricture. Length +of the two joints = 1 : 4, breadth = 2 : 10. Cephalis hemispherical, with a +slender occipital horn of three times the length, and a small divergent +frontal horn. Thorax with three strong prominent straight ribs and +irregular polygonal meshes, increasing in size towards the mouth. Peristome +with a dense coronal of numerous short conical spines and twenty-four to +thirty larger arborescent spines, longer than the diameter of the cephalis. + +_Dimensions._--Cephalis 0.02 long, 0.04 broad; thorax 0.08 long, 0.2 broad. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + + +Genus 543. _Callimitra_,[160] Haeckel, Prodromus, 1881, p. 431. + +_Definition._--#Sethopilida# (vel Dicyrtida triradiata aperta) with three +vertical latticed wings, which stretch between the three divergent lateral +ribs of the thorax and the vertical horn of the cephalis. No frontal horn. + +{1217}The genus _Callimitra_, and the two following nearly allied genera, +_Clathromitra_ and _Clathrocorys_, form together a peculiar small group, +the Callimitrida, living in the Central Pacific, and differing from the +other Sethopilida in some remarkable points, derived perhaps directly from +the Archiscenida, _Archiscenium_ and _Pteroscenium_, by the development of +thoracic network between the three cortinar feet. In the centre of the +collar septum, where these feet are united, there arises a vertical free +columella, prolonged over the top of the cephalis as a free horn, and this +horn is connected with the three thoracic ribs by three vertical +fenestrated wings. + + +1. _Callimitra carolotae_, n. sp. (Pl. 63, figs. 1, 7, 8). + +Cephalis campanulate, conical, with irregular, polygonal pores, and a thin +bristle-shaped apical horn of the same length. Length of the two joints = +3 : 6, breadth = 2 : 6. Thorax in the upper half with irregular network, in +the lower half with parallel transverse bars; in each of its three sides +descend two convergent pairs of stronger, parallel, curved ribs, not +confluent at the peristome. Each of the three vertical wings with eight +stronger ribs, three arising from the cephalis, five from each foot. +Dedicated to my dear mother Charlotte Sethe. + +_Dimensions._--Cephalis 0.07 long, 0.05 broad; thorax 0.15 long, 0.15 +broad. + +_Habitat._--Central Pacific, Station 270, depth 2925 fathoms. + + +2. _Callimitra annae_, n. sp. (Pl. 63, fig. 2). + +Cephalis campanulate, conical, with irregular, polygonal pores, and a thin +bristle-shaped horn of the same length. Length of the two joints = 1 : 2, +breadth = 1 : 3. Thorax nearly in its whole extent with parallel transverse +bars, which are crossed by two convergent systems of parallel beams; in +each of its three sides descend four convergent pairs of stronger, +parallel, curved ribs, not confluent at the peristome. Each of the three +vertical wings with six stronger ribs, three arising from the cephalis, +three from each foot. Dedicated to my dear first wife Anna Sethe. + +_Dimensions._--Cephalis 0.05 long, 0.05 broad; thorax 0.12 long, 0.18 +broad. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +3. _Callimitra agnesae_, n. sp. (Pl. 63, fig. 5). + +Cephalis pear-shaped, with irregular, square pores, and a slender +bristle-shaped horn twice as long. Length of the two joints = 1 : 3, +breadth = 1 : 5. Thorax in its whole extent with parallel transverse bars, +which are crossed by two converging and crossed systems of parallel beams; +in each of its three sides descend five convergent pairs of stronger, +parallel, curved ribs, the two or three upper of which are crossed at the +peristome. Each of the three vertical wings with five stronger ribs, three +arising from the cephalis and the horn, two from each foot. Dedicated to +my dear second wife Agnes Huschke. + +_Dimensions._--Cephalis 0.05 long, 0.05 broad; thorax 0.15 long, 0.22 +broad. + +_Habitat._--Central Pacific, Station 273, depth 2350 fathoms. + + +{1218}4. _Callimitra elisabethae_, n. sp. (Pl. 63, fig. 6). + +Cephalis nearly hemispherical, with irregular square pores, and a strong +prismatic horn thrice the length. Length of the two joints = 2 : 7, breadth += 2 : 9. Thorax in the upper third with irregular network, in the lower +two-thirds with parallel transverse bars which are crossed by two +convergent systems of parallel beams; in each of its three sides descend +three convergent pairs of stronger, parallel, curved ribs; the two ribs of +the uppermost pair are united and confluent in a single odd rib in the +lower half of the thorax. Each of the three vertical wings with seven +stronger ribs, three arising from the cephalis and the horn, four from each +foot. Dedicated to my dear elder daughter Elizabeth Haeckel. + +_Dimensions._--Cephalis 0.04 long, 0.05 broad; thorax 0.15 long, 0.2 broad. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +5. _Callimitra emmae_, n. sp. (Pl. 63, figs. 3, 4). + +Cephalis campanulate, with irregular, polygonal pores, and very thin bars +(of the same shape as in the thorax) and with a thin bristle-shaped horn +twice the length. Length of the three joints = 3 : 6, breadth = 2 : 9. +Thorax in its whole extent with an arachnoidal network similar to that in +the cephalis and the three wings, composed of very numerous parallel +threads, which are crossed by two crossed diagonal systems of parallel +threads. In each of the three sides of the thorax descend five convergent +pairs of stronger ribs, the three upper of which are crossed and form large +rhomboidal meshes. Each of the three vertical wings with ten stronger ribs, +four arising from the cephalis and each horn, six from each foot. Dedicated +to my dear younger daughter Emma Haeckel. + +_Dimensions._--Cephalis 0.07 long, 0.06 broad; thorax 0.15 long, 0.22 +broad. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + + +Genus 544. _Clathromitra_,[161] Haeckel, 1881, Prodromus, p. 432. + +_Definition._--#Sethopilida# (vel Dicyrtida triradiata aperta) with three +vertical latticed wings, which stretch between the three divergent lateral +ribs of the thorax and the vertical horn of the cephalis. The front of the +latter is armed with a large frontal horn. + +The genus _Clathromitra_ differs from the preceding similar _Callimitra_ in +the development of a free frontal or sternal horn, a prolongation of an +internal obliquely ascending rod, opposite to the caudal foot. Therefore +the shell in this genus possesses five divergent free spines, two cephalic +horns, and three thoracic feet. The lattice-work of the three vertical +wings is not so delicate as in _Callimitra_. + + +{1219}1. _Clathromitra pterophormis_, n. sp. (Pl. 57, fig. 8). + +Cephalis very large, hemispherical, about as long and half as broad as the +three-sided pyramidal thorax; both with irregular, polygonal meshes. Apical +horn three to four times as long as the frontal horn and the three basal +feet. All five spines three-sided prismatic, with nearly smooth edges. +Three lateral wings half as broad as the cephalis. + +_Dimensions._--Cephalis 0.05 long, 0.1 broad; thorax 0.05 long, 0.15 broad. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +2. _Clathromitra pentacantha_, n. sp. + +Cephalis large, hemispherical, half as long as the three-sided pyramidal +thorax; both with irregular, roundish meshes. Apical horn of about the same +length as the frontal horn, and twice as long as the three basal feet. All +five spines three-sided prismatic, with denticulated edges. Three lateral +wings about as broad as the cephalis. + +_Dimensions._--Cephalis 0.04 long, 0.08 broad; thorax 0.1 long, 0.2 broad. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + + +Genus 545. _Clathrocorys_,[162] Haeckel, 1881, Prodromus, p. 432. + +_Definition._--#Sethopilida# (vel Dicyrtida triradiata aperta) with three +prominent lateral ribs on the thorax, alternating with three large holes +(or thoracic gates). The three ribs are connected with the central apical +horn of the cephalis by three vertical latticed wings. + +The genus _Clathrocorys_ differs from the two preceding nearly allied +genera in the incomplete fenestration of the thorax, the three perradial +ribs of which are separated by three large interradial holes. It has +therefore the same relation to _Callimitra_ that _Clathrocanium_ bears to +_Dictyophimus_. + + +1. _Clathrocorys murrayi_, n. sp. (Pl. 64, fig. 8). + +Cephalis pear-shaped, with irregularly square pores. From the centre of its +base there arise four strong, prismatic, radial beams of nearly equal size, +the vertical, straight, cephalic horn being little longer than the three +divergent, somewhat curved feet. In the three meridional planes (between +the horn and each foot) a few rather thick branches arise, which by +communication of the ramules form the three vertical latticed wings; each +wing with two large meshes, three to five meshes of medium size, and three +to four parallel arachnoidal rows of small, square, distal meshes. The +three walls of the flat pyramidal thorax (between every two feet) are +formed in the upper part by squarish network {1220}similar to that of the +cephalis, in the middle part by a single row of arches separated by thin +threads, and in the lower part by a narrow band of arachnoidal network. +Dedicated to Dr. John Murray. + +_Dimensions._--Cephalis 0.05 long, 0.05 broad; thorax 0.04 long, 0.15 +broad; apical distance of every two feet 0.15, of each foot and the horn +0.17. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +2. _Clathrocorys teuscheri_, n. sp. (Pl. 64, fig. 10). + +Cephalis pear-shaped, with irregular, square pores. From the centre of its +base there arise seven prismatic, radial beams of equal strength, +supporting the lattice-work of the wall; the single vertical beam is +prolonged into the apical horn; six others lie in the three meridian planes +(between the horn and each foot); three ascending end in the wall of the +cephalis, three descending are prolonged into the three strong feet, which +are longer than the horn. In each meridional plane there arise four thicker +and several thinner bars, which by communication of their ramules form the +three latticed wings; each wing with a single very large mesh, two meshes +of medium size, and a narrow marginal band of small, square pores. The +three walls of the flat pyramidal thorax are formed in the upper part by +squarish network similar to that of the cephalis, in the lower part by a +narrow band of the same; between them a large hole. Dedicated to Dr. +Reinhold Teuscher. + +_Dimensions._--Cephalis 0.05 long, 0.04 broad; thorax 0.06 long, 0.15 +broad; apical distance of every two feet 0.2, of each foot and the horn +0.2. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +3. _Clathrocorys giltschii_, n. sp. (Pl. 64, fig. 9). + +Cephalis pear-shaped, with irregular, polygonal pores. From the centre of +its base there arise seven prismatic, radial beams of different strength; +the single vertical beam bears six lateral branches (parallel to the three +ascending supporting beams), and is prolonged into the apical horn; six +others lie in the three meridional planes (between the horn and each foot); +three weaker ascending beams end in the wall of the cephalis, three +stronger descending are prolonged into the three large diverging feet, +which are twice as long as the cephalic horn. The network of the three +wings and of the three-sided pyramidal thorax is about the same as in the +preceding species, but much more developed; the marginal bands with the +squarish network are much broader, and an arachnoidal wicker-work of very +thin thread-like bars fills out the large meshes. Dedicated to Mr. Adolf +Giltsch. + +_Dimensions._--Cephalis 0.04 long, 0.04 broad; thorax 0.12 long, 0.2 broad; +apical distance of every two feet 0.24, of each foot and the horn 0.2. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + + +Genus 546. _Eucecryphalus_,[163] Haeckel, 1860, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 836. + +_Definition._--#Sethopilida# (vel Dicyrtida triradiata aperta) with three +free collar {1221}wings or solid spines arising from the collar stricture, +and freely prominent between the horned cephalis and the flat conical +thorax. + +The genus _Eucecryphalus_, according to the restricted definition here +given, comprises only those Sethopilida in which the three primary cortinar +beams are perfectly free divergent collar wings, _i.e._, free spines +arising outside the shell from the collar stricture, between the cephalis +and thorax. The type of this genus (which I formerly united with other +Sethopilida) remains _Eucecryphalus gegenbauri_. + + + +Subgenus 1. _Eucyrtomphalus_, Haeckel, 1881, Prodromus, p. 431. + +_Definition._--Peristome or margin of the basal mouth of the thorax smooth, +without marginal spines. + + +1. _Eucecryphalus corocalyptra_, n. sp. + +Shell flatly conical, with slight collar stricture. Length of the two +joints = 1 : 3, breadth = 1 : 6. Cephalis subspherical, with an oblique +conical horn twice its length. Thorax conical, twice as broad as long, with +regular hexagonal meshes and straight lateral outlines. From the collar +stricture there arise three slender conical spines, about as long as the +thorax, divergent downwards. Similar to _Corocalyptra agnesae_ (Pl. 59, +fig. 3), but without lumbar stricture and abdomen. Peristome or basal +margin of the mouth of the thorax smooth, simple. + +_Dimensions._--Cephalis 0.3 diameter; thorax 0.09 long, 0.18 broad. + +_Habitat._--Cosmopolitan; Atlantic, Indian, Pacific, surface. + + +2. _Eucecryphalus halicalyptra_, n. sp. + +Shell flat, campanulate, with distinct collar stricture. Length of the two +joints = 1 : 4, breadth = 2 : 10. Cephalis hemispherical, with two +divergent conical horns, a major occipital and a minor frontal horn. Thorax +with subregular hexagonal meshes and concave-convex lateral outlines, +campanulate. From the collar stricture there arise three divergent +bristle-shaped spines, nearly horizontal, about half as long as the thorax. +Peristome smooth, with a marginal coronal of small square pores. + +_Dimensions._--Cephalis 0.02 long, 0.04 broad; thorax 0.08 long, 0.2 broad. + +_Habitat._--Central Pacific, Stations 266 to 274, surface. + + + +Subgenus 2. _Eucecryphalium_, Haeckel. + +_Definition._--Peristome or margin of the basal mouth of the thorax +dentate, with a coronal of marginal spines. + + +{1222}3. _Eucecryphalus cuvieri_, n. sp. + +Shell flatly conical, with slight collar stricture. Length of the two +joints = 1 : 8, breadth = 2 : 10. Cephalis hemispherical, with an oblique +pyramidal horn twice as long. Thorax with straight outlines and regular +hexagonal meshes, increasing in size towards the mouth. From the collar +stricture there arise three stout conical spines, half as long as the +thorax, and diverging downwards. Peristome with a ring of small square +pores and alternate conical divergent spines. Differs from the similar +_Clathrocyclas alcmenae_ (Pl. 59, fig. 6), mainly in the simple apical horn +and the possession of the three collar fundamental spines. + +_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.15 long, 0.2 broad. + +_Habitat._--Tropical Atlantic, Station 342, depth 1445 fathoms. + + +4. _Eucecryphalus muelleri_, n. sp. + +Shell flatly campanulate, of nearly the same structure as and similar form +to that of the preceding species. Differs from it mainly in the +considerable size of the cephalic horn and the three collar spines, which +are bristle-shaped and longer than the shell. Length of the two joints = +1 : 4, breadth = 2 : 8. The peristome bears a double marginal ring of +divergent conical spines, the upper being directed upwards, the lower +downwards. + +_Dimensions._--Cephalis 0.02 long, 0.04 broad; thorax 0.08 long, 0.16 +broad. + +_Habitat._--North Pacific, Station 241, depth 2300 fathoms. + + +5. _Eucecryphalus gegenbauri_, Haeckel. + + _Eucecryphalus gegenbauri_, Haeckel, 1862, Monogr. d. Radiol., p. 308, + Taf. v. figs. 12-15. + + _Eucecryphalus gegenbauri_, R. Hertwig, 1879, Organism. d. Radiol., p. + 76, Taf. viii. figs. 5, 5_a_, 5_b_. + +Shell flatly conical, campanulate, with slight collar stricture. Length of +the two joints = 1 : 4, breadth = 1 : 8. Cephalis hemispherical, with a +conical horn of the same length, and very small pores. Thorax about twice +as broad as high, with large, subregular, hexagonal meshes, increasing in +size downwards. In the upper half of the thorax the meshes are filled up by +an extremely delicate arachnoidal network. From the collar stricture there +arise three divergent bristle-shaped spines half as long as the thorax. +Peristome with a double coronal of small square pores (the inner smaller +and more numerous than the outer), and with a single coronal of divergent +marginal spines. This cosmopolitan species is rather variable. + +_Dimensions._--Cephalis 0.02 to 0.03 diameter; thorax 0.1 to 0.12 long, +0.02 to 0.25 broad. + +_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Indian, Pacific, +surface. + + +{1223}6. _Eucecryphalus campanella_, Haeckel. + + _Pterocodon campanella_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 82, Taf. xix. fig. 2. + +Shell campanulate, conical, with sharp collar stricture. Length of the two +joints = 1 : 3, breadth = 1 : 2. Cephalis hemispherical, with a short +conical horn half as long, and very small pores. Thorax campanulate, as +broad as high, with large roundish meshes, increasing in size downwards. +From the collar stricture arise three strong, divergent, somewhat curved +spines, nearly as long as the thorax. Peristome with a coronal of ten to +twelve strong, conical, marginal spines, which are nearly parallel, +directed downwards, a little curved, and half as long as the thorax. In the +complete specimen examined by me, the apical horn, the three lateral wings +and twelve terminal feet were well preserved. + +_Dimensions._--Cephalis 0.02 to 0.03 diameter; thorax 0.06 to 0.07 long and +broad. + +_Habitat._--Fossil in Barbados. + + + +Genus 547. _Amphiplecta_,[164] Haeckel, 1881, Prodromus, p. 424. + +_Definition._--#Sethopilida# (vel Dicyrtida triradiata aperta) with three +internal thoracic ribs, enveloped by the network of the thorax. Cephalis +with a large apical opening, surrounded by a coronal of spines. + +The genus _Amphiplecta_ (or _Amphicryphalus_) comprises some very peculiar +forms of Sethopilida, probably widely remote from the other genera of this +subfamily, and derived directly from the Plectanida (compare above, p. +921). The cortinar tripodium, composed of three feet divergent downwards, +and one apical horn ascending upwards (in some species also a second +frontal horn) is here enclosed in the cavity of a two-jointed shell, which +exhibits two large openings, a smaller apical hole in the top of the +cephalis, and a larger terminal mouth on the thorax. There is no trace of a +sagittal ring. + + +1. _Amphiplecta amphistoma_, n. sp. + +Cephalis subspherical, spiny, with sharp collar stricture on the base; its +apical opening central, surrounded by a coronal of twelve to eighteen short +spines. Length of the two joints = 7 : 8, breadth = 6 : 20. Thorax flatly +conical, armed with bristle-shaped spines. Meshes of the network in both +joints subregular, hexagonal, six to eight times as broad as the bars. +Basal mouth bristly. + +_Dimensions._--Cephalis 0.07 long, 0.06 broad; thorax 0.08 long, 0.2 broad. + +_Habitat._--Central Pacific, Station 274, surface. + + +2. _Amphiplecta acrostoma_, n. sp. (Pl. 97, fig. 10). + +Cephalis subspherical, spiny, with distinct collar stricture on the base, +its apical opening central, surrounded by a coronal of six to nine +divergent denticulate spines. Length of the two joints = 5 : 6, +{1224}breadth = 4 : 15. Thorax flatly conical, armed with denticulate +spines. Meshes of both joints irregular, polygonal, twice to six times as +broad as the bars. Basal mouth armed with longer, divergent, denticulate +spines. + +_Dimensions._--Cephalis 0.05 long, 0.04 broad; thorax 0.06 long, 0.15 +broad. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +3. _Amphiplecta callistoma_, n. sp. (Pl. 59, fig. 2). + +Cephalis flat, cap-shaped, spiny, with obliterated collar stricture on the +base; its apical opening excentric, oblique, surrounded by a coronal of ten +to twenty bristle-shaped spines. Length of the two joints = 4 : 5, breadth += 7 : 25. Thorax flatly conical, armed with long bristle-shaped spines. +Meshes of both joints irregular, hexagonal, twice to six times as broad as +the bars. Basal mouth with a double irregular coronal of small square +pores, and of bristle-shaped divergent spines. + +_Dimensions._--Cephalis 0.04 long, 0.07 broad; thorax 0.05 long, 0.25 +broad. + +_Habitat._--Central Pacific, Station 271, surface. + + + +Genus 548. _Lychnocanium_,[165] Ehrenberg, 1847, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 54. + +_Definition._--#Sethopilida# (vel Dicyrtida triradiata aperta), with three +solid terminal feet on the peristome. No thoracic ribs. Cephalis with a +horn. + +The genus _Lychnocanium_, very rich in common living and fossil forms, +comprises those Sethopilida in which the thorax bears three simple terminal +feet around the mouth, but no lateral ribs in its wall. It has therefore +been probably derived from _Dictyophimus_ by reduction and loss of these +three lateral ribs. The mouth is commonly more or less constricted. The +three feet surrounding it are sometimes divergent, straight or curved, at +other times parallel and vertical, straight, or curved and convergent. The +central capsule exhibited in some living species three or four distinct +lobes, filling up the upper half of the thorax. + + + +Subgenus 1. _Lychnocanella_, Haeckel. + +_Definition._--Feet divergent, straight or scarcely curved; their terminal +distance greater than their basal distance. + + +1. _Lychnocanium lanterna_, n. sp. (Pl. 61, fig. 7). + +Shell conical, rough, with slight collar stricture. Length of the two +joints = 1 : 3, breadth = 1 : 3. Cephalis with a stout pyramidal horn of +the same length. Thorax pear-shaped, twice as {1225}broad as the +constricted mouth, with regular, circular pores of the same breadth as the +bars. Three feet pyramidal, little divergent, straight, about as long as +the cephalis. + +_Dimensions._--Cephalis 0.03 long, 0.03 broad; thorax 0.09 long, 0.08 +broad. + +_Habitat._--Central Pacific, Stations 263 to 268, depth 2650 to 2900 +fathoms. + + +2. _Lychnocanium continuum_, Ehrenberg. + + _Lychnocanium continuum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 78, Taf. vii. fig. 11. + +Shell smooth, with distinct collar stricture. Length of the two joints = +1 : 3, breadth = 1 : 3. Cephalis subspherical with a conical horn of the +same length. Thorax pear-shaped, twice as broad as the constricted mouth, +nearly hyaline, with a very small number of scattered minute pores. Three +feet pyramidal, little divergent, straight, about as long as the thorax. + +_Dimensions._--Cephalis 0.02 long, 0.02 broad; thorax 0.06 long, 0.06 +broad. + +_Habitat._--Fossil in Barbados. + + +3. _Lychnocanium pyriforme_, n. sp. (Pl. 61, fig. 11). + +Shell pear-shaped, rough, with sharp collar stricture. Length of the two +joints = 1 : 4, breadth = 1 : 5. Cephalis hemispherical, with a conical +horn of the same length. Thorax inflated, four times as broad as the +constricted tubular mouth, with regular, circular pores. Three feet +pyramidal, straight, divergent, about as long as the thorax. + +_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.12 long, 0.15 +broad. + +_Habitat._--Cosmopolitan; Atlantic, Indian, Pacific, many Stations; also +fossil in Barbados. + + +4. _Lychnocanium favosum_, n. sp. (Pl. 61, fig. 6). + +Shell campanulate, rough, with slight collar stricture. Length of the two +joints = 1 : 5, breadth = 1 : 6. Cephalis hemispherical, with a rudimentary +pyramidal horn of half the length. Thorax subglobular, three times as broad +as the constricted mouth, with regular, circular pores, and an elevated +hexagonal framework between them. Three feet cylindrical, slender, +straight, divergent, twice to three times as long as the thorax. + +_Dimensions._--Cephalis 0.02 long, 0.025 broad; thorax 0.1 long, 0.12 +broad. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +5. _Lychnocanium nodosum_, n. sp. (Pl. 61, fig. 14). + +Shell campanulate, nodose, with deep collar stricture. Length of the two +joints = 1 : 3, breadth = 1 : 4. Cephalis subglobular, with a rudimentary +conical horn of half the length. Thorax nearly hemispherical, twice as +broad as the flat mouth, with regular, circular pores, and a variable +{1226}number of scattered, conical, fenestrated protuberances. Three feet +very large, prismatic, straight, divergent, twice as long as the thorax. + +_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.09 long, 0.12 +broad. + +_Habitat._--North Pacific, Station 253, depth 3125 fathoms. + + +6. _Lychnocanium carinatum_, Ehrenberg. + + _Lychnocanium carinatum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 78, Taf. viii. fig. 5. + +Shell campanulate, with deep collar stricture. Length of the two joints = +1 : 3, breadth = 1 : 3. Cephalis subglobular, with a slender horn of the +same length. Thorax conical, twice as broad as the flat mouth, with fifteen +to twenty prominent, longitudinal, divergent ribs, alternating with the +same number of rows of pores. Three feet slender, prismatic, straight, +divergent, twice as long as the thorax. + +_Dimensions._--Cephalis 0.02 long, 0.02 broad; thorax 0.06 long, 0.06 +broad. + +_Habitat._--Fossil in Barbados. + + +7. _Lychnocanium ventricosum_, Ehrenberg. + + _Lychnocanium ventricosum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 80, Taf. vii. fig. 12. + +Shell pear-shaped, rough, with deep collar stricture. Length of the two +joints = 1 : 3, breadth = 1 : 4. Cephalis subglobular, with a stout conical +horn twice the length. Thorax conical, three times as broad as the +constricted mouth, with irregular, roundish pores of different sizes. Three +feet stout, conical, divergent, half as long as the thorax. + +_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.07 long, 0.09 +broad. + +_Habitat._--Central Pacific, Stations 265 to 268, depth 2700 to 2900 +fathoms; fossil in Barbados. + + +8. _Lychnocanium tribulus_, Ehrenberg. + + _Lychnocanium tribulus_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 80, Taf. vii. fig. 1. + +Shell pear-shaped, nodose, with distinct collar stricture. Length of the +two joints = 1 : 4, breadth = 1 : 4. Cephalis subglobular, with a conical +horn twice the length. Thorax ovate, twice as broad as the constricted +mouth, with irregular, roundish pores of different sizes. Three stout feet +strongly divergent, pyramidal, about as long as the thorax. + +_Dimensions._--Cephalis 0.02 long, 0.02 broad; 0.08 long, 0.08 broad. + +_Habitat._--Fossil in Barbados. + + + +Subgenus 2. _Lychnocanissa_, Haeckel. + +_Definition._--Feet divergent, more or less curved; their terminal distance +greater than their basal distance. + + +{1227}9. _Lychnocanium fortipes_, n. sp. (Pl. 61, fig. 12). + +Shell inflated, rough, with distinct collar stricture. Length of the two +joints = 1 : 5, breadth = 1 : 6. Cephalis small, hemispherical, with a +pyramidal horn of half the length. Thorax subglobular, truncate, twice as +broad as the constricted mouth, with large, regular, circular pores and +very thin bars. Three feet very stout, prismatic, twice as long as the +thorax, widely divergent, curved with convexity outwards, club-shaped at +the distal end, with denticulate edges. + +_Dimensions._--Cephalis 0.02 long, 0.02 broad; thorax 0.1 long, 0.12 broad. + +_Habitat._--Equatorial Atlantic, Station 347, depth 2250 fathoms. + + +10. _Lychnocanium falciferum_, Ehrenberg. + + _Lychnocanium falciferum_, Ehrenberg, 1854, Mikrogeol., Taf. xxxvi. fig. + 7; Abhandl. d. k. Akad. d. Wiss. Berlin, p. 78, Taf. viii. fig. 4. + + _Lithomelissa falcifera_, Haeckel, 1862, Monogr. d. Radiol., p. 303. + +Shell inflated, rough, with deep collar stricture. Length of the two joints += 1 : 3, breadth = 1 : 3. Cephalis small, with a conical horn of half the +length. Thorax subglobular, truncate, three times as broad as the +constricted mouth, with small, regular, circular pores. Three feet widely +divergent, twice as long as the thorax, curved like a crescent, with strong +convexity outwards. + +_Dimensions._--Cephalis 0.02 long, 0.02 broad; thorax 0.06 long, 0.06 +broad. + +_Habitat._--Fossil in Barbados. + + +11. _Lychnocanium tuberosum_, n. sp. (Pl. 61, fig. 13). + +Shell conical, tuberculate, with deep collar stricture. Length of the two +joints = 1 : 3, breadth = 1 : 4. Cephalis subglobular, with a conical horn +of the same length. Thorax inflated, twice as broad as the flat mouth, with +small, irregular, roundish pores and scattered fenestrated tubercles. Three +feet very large, angular, three times as long as the thorax, curved like a +crescent, with strong convexity outwards. + +_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.08 long, 0.12 +broad. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +12. _Lychnocanium hirundo_, Ehrenberg. + + _Lychnocanium hirundo_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 80, Taf. vii. fig. 8. + + _Lithornithium hirundo_, Ehrenberg, 1854, Mikrogeol., Taf. xix. fig. 53. + + _Lithocampe hirundo_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 65. + +Shell conical, tuberculate, with slight collar stricture. Length of the two +joints = 1 : 3, breadth = 1 : 4. Cephalis hemispherical, with a conical +horn of half the length. Thorax {1228}campanulate, twice as broad as the +flat mouth, with longitudinal, divergent ribs, alternating with rows of +small circular pores. Three feet divergent, striated, gradually lessening +from a broad base, twice as long as the thorax, curved like a crescent, +with convexity outwards. + +_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.06 long, 0.08 +broad. + +_Habitat._--Fossil in Tertiary rocks of Barbados and the Mediterranean +(Sicily, Greece). + + +13. _Lychnocanium fenestratum_, n. sp. (Pl. 61, fig. 10). + +Shell pear-shaped, rough, with slight collar stricture. Length of the two +joints = 1 : 4, breadth = 1 : 3. Cephalis subglobular, with a very large +prismatic horn, which is about as long as the shell, with three +denticulate, prominent, wing-like crests, which are pierced by a series of +pores. Thorax ovate, three times as broad as the constricted, prominent +mouth, with subregular, circular pores. Three feet arising somewhat above +the mouth, prismatic, with denticulate edges, about as long as the thorax, +divergent, curved, with convexity outwards. + +_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.08 long, 0.08 +broad. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +14. _Lychnocanium sigmopodium_, n. sp. (Pl. 61, fig. 15). + + ? _Lychnocanium tetrapodium_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 80, Taf. vii. fig. 3. + +Shell campanulate, rough with distinct collar stricture. Length of the two +joints = 1 : 4, breadth = 1 : 3. Cephalis subspherical, with a slender +pyramidal horn twice the length. Thorax inflated, conical, with regular +circular pores and a wide open mouth of nearly the same breadth. Three feet +widely divergent, twice as long as the thorax, angular, S-shaped, or curved +with convexity inwards. (_Lychnocanium tetrapodium_ of Ehrenberg is perhaps +a variety of this species?). + +_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.08 long, 0.09 +broad. + +_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Pacific, many stations +at various depths; also fossil in Barbados and Sicily. + + +15. _Lychnocanium trichopus_, Ehrenberg. + + _Lychnocanium trichopus_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 80, Taf. vii. fig. 5. + +Shell conical, smooth, with deep collar stricture. Length of the two joints += 1 : 3, breadth = 1 : 3. Cephalis subspherical, with a rudimentary conical +horn of half the length. Thorax campanulate, with regular, circular pores +and wide open mouth of nearly the same breadth. Three feet divergent, very +slender, four to five times as long as the thorax, not broader than one +pore, S-shaped, or curved with convexity inwards in the distal half. + +_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.07 long, 0.09 +broad. + +_Habitat._--Fossil in Barbados. + + + +{1229}Subgenus 3. _Lychnocanoma_, Haeckel. + +_Definition._--Feet parallel, vertical, straight, or little curved; +divergent in the basal half, often convergent in the distal half; their +terminal distance about equal to the basal distance. + + +16. _Lychnocanium tripodium_, Ehrenberg. + + _Lychnocanium tripodium_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 80, Taf. vii. fig. 2. + +Shell ovate, smooth, with distinct collar stricture. Length of the two +joints = 1 : 4, breadth = 1 : 4. Cephalis subglobular, with a slender +conical horn twice the length. Thorax inflated, twice as broad as the +constricted mouth, with small, regular, circular pores. Three feet slender, +prismatic, twice to three times as long as the thorax, nearly straight and +parallel, vertical. + +_Dimensions._--Cephalis 0.02 long, 0.02 broad; thorax 0.07 long, 0.07 +broad. + +_Habitat._--Central Pacific, Stations 265 to 268, depth 2700 to 2900 +fathoms; also fossil in Barbados. + + +17. _Lychnocanium cypselus_, Ehrenberg. + + _Lychnocanium cypselus_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 78, Taf. vii. fig. 10. + +Shell slender, ovate, with slight collar stricture. Length of the two +joints = 1 : 4, breadth = 1 : 3. Cephalis subspherical, with a conical horn +of the same length. Thorax ovate, truncate, three times as broad as the +narrow, constricted mouth, with small, regular, circular pores. Three feet +slender, somewhat shorter than the thorax, little curved, with convexity +outwards, nearly parallel, vertical. (In the specimen figured by Ehrenberg, +the third foot was broken off.) + +_Dimensions._--Cephalis 0.02 long, 0.02 broad; thorax 0.08 long, 0.06 +broad. + +_Habitat._--Fossil in Barbados. + + +18. _Lychnocanium ovatum_, n. sp. + +Shell ovate, rough, without external collar stricture. Length of the two +joints = 1 : 6, breadth = 1 : 5. Cephalis conical, with a stout conical +horn of the same length. Thorax ovate, four times as broad as the narrow +constricted mouth, with small, regular, circular pores, separated by +hexagonal frames of twice the breadth. Three feet cylindrical, half as long +as the thorax, and three times as long as broad, straight, parallel, +vertical. + +_Dimensions._--Cephalis 0.02 long, 0.02 broad; thorax, 0.12 long, 0.1 +broad. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +{1230}19. _Lychnocanium crassipes_, Ehrenberg. + + _Lychnocanium crassipes_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 78, Taf. vii. fig. 7. + +Shell campanulate, rough, with deep collar stricture. Length of the two +joints = 1 : 3, breadth = 1 : 4. Cephalis subspherical, with a thin conical +horn of the same length. Thorax semi-ovate, three times as broad as the +narrow constricted mouth, with fifteen to twenty divergent, denticulate +ribs, alternating with the same number of rows of small, regular, circular +pores. Three feet very stout, as long as the thorax, cylindrical, nearly +straight and parallel, vertical, at the distal end clavate, spinulate or a +little forked. + +_Dimensions._--Cephalis 0.02 long, 0.02 broad; thorax 0.06 long, 0.08 +broad. + +_Habitat._--Fossil in Barbados. + + +20. _Lychnocanium clavigerum_, n. sp. (Pl. 61, fig. 4). + +Shell campanulate, sulcate, with sharp collar stricture. Length of the two +joints = 1 : 4, breadth = 1 : 5. Cephalis subglobular, with a +spindle-shaped papillate horn twice the length. Thorax nearly spherical, +truncate at both poles, three times as broad as the narrow, constricted, +somewhat tubular mouth, with fifteen to twenty elevated meridional ribs, +alternating with the same number of rows of circular pores. Three feet +slender, cylindrical, twice as long as the thorax, in the basal half +divergent, in the distal half convergent, club-shaped, with a thickened +papillate end. + +_Dimensions._--Cephalis 0.02 long, 0.025 broad; thorax 0.08 long, 0.01 +broad. + +_Habitat._--Indian Ocean, Madagascar, surface (Rabbe). + + +21. _Lychnocanium pudicum_, n. sp. (Pl. 61, fig. 2). + +Shell campanulate, with deep collar stricture. Length of the two joints = +1 : 3, breadth = 1 : 3. Cephalis hemispherical, hyaline (without pores), +with a short and thick club-shaped, spinulate horn of the same length. +Thorax subglobular, truncate at both poles, twice as broad as the +constricted mouth, with small, irregular, roundish pores. Three feet +somewhat shorter than the thorax, curved like a crescent, with convexity +outwards; their distal ends club-shaped, spinulate, convergent towards the +central axis. + +_Dimensions._--Cephalis 0.02 long, 0.025 broad; thorax 0.06 long, 0.07 +broad. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + + +Genus 549. _Lychnodictyum_,[166] Haeckel, 1881, Prodromus, p. 432. + +_Definition._--#Sethopilida# (vel Dicyrtida triradiata aperta), with three +latticed terminal feet on the peristome, without thoracic ribs. Cephalis +originally with a horn (sometimes lost). + +{1231}The genus _Lychnodictyum_ differs from the preceding _Lychnocanium_ +only in the fenestration of the three terminal feet, and bears therefore to +it the same relation that the ancestral _Tripocyrtis_ does to +_Dictyophimus_. + + +1. _Lychnodictyum challengeri_, Haeckel. + + _Dictyopodium challengeri_, Wyville Thomson, 1877, Atlantic, vol. i. p. + 234, fig. 52. + + _Dictyophimus_ (vel _Tripocyrtis_) _challengeri_, Haeckel, 1878, + Protistenreich, p. 47, fig. 35. + +Shell campanulate, smooth, with sharp collar stricture. Length of the two +joints = 1 : 3, breadth = 1 : 4. Cephalis subspherical, with a large, +oblique, pyramidal horn thrice the length. Thorax with three inflated +bosoms between the three decurrent ribs, which are prolonged into three +vertical, parallel, pyramidal, in the upper half fenestrated feet, as long +as the thorax. Pores regular, circular. Mouth constricted, flat, half as +broad as the thorax. + +_Dimensions._--Cephalis 0.03 diameter; thorax 0.08 long, 0.12 broad. + +_Habitat._--Tropical Atlantic, Station 338, depth 1990 fathoms. + + +2. _Lychnodictyum wyvillei_, n. sp. + +Shell pyramidal, smooth, with obliterated collar stricture. Length of the +two joints = 1 : 3, breadth = 1 : 5. Cephalis subspherical, with a large, +straight, pyramidal horn of twice the length. Thorax nearly tetrahedral, +inflated, with three rounded, decurrent ribs, which are prolonged into +three widely divergent, angular, curved feet, about as long as the shell, +with pyramidal fenestrated base. Pores regular, circular. Mouth +constricted, flat, half as broad as the thorax. + +_Dimensions._--Cephalis 0.025 diameter; thorax 0.08 long, 0.12 broad. + +_Habitat._--Central Pacific, Stations 266 to 274, depth 2350 to 2925 +fathoms. + + +3. _Lychnodictyum scaphopodium_, n. sp. (Pl. 56, fig. 4). + +Cephalis hemispherical, large, without horn, with irregular, small, +roundish pores. Thorax a little larger, campanulate, with three broad, +shovel-shaped, fenestrated, vertical feet, and larger, irregular pores. In +the figured specimen the third (posterior) foot was broken off. In another +specimen the three feet were somewhat longer and not so broad. + +_Dimensions._--Cephalis 0.03 long, 0.05 broad; thorax 0.05 long, 0.06 +broad. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + +4. _Lychnodictyum sethopodium_, n. sp. + +Cephalis hemispherical, large, with a rudimentary conical horn, and very +scarce small pores. Thorax twice as broad and long as the cephalis, +campanulate, with irregular, roundish pores, and three slender, pyramidal, +divergent feet twice the length, which in the upper half are fenestrated, +in the lower half solid. + +_Dimensions._--Cephalis 0.025 long, 0.045 broad; thorax 0.05 long, 0.09 +broad. + +_Habitat._--South Atlantic, Station 330, surface. + + + +{1232}Subfamily 2. SETHOPERIDA, Haeckel, 1881, Prodromus, p. 433. + +_Definition._--#Tripocyrtida# with the basal mouth of the shell fenestrated +(vel Dicyrtida triradiata clausa). + + + +Genus 550. _Sethopera_,[167] Haeckel, 1881, Prodromus, p. 433. + +_Definition._--#Sethoperida# (vel Dicyrtida triradiata clausa), with three +divergent ribs enclosed in the latticed wall of the thorax. Cephalis with a +horn. + +The genus _Sethopera_ is probably the oldest form of the Sethoperida, and +may therefore be regarded as the common ancestral form of this subfamily. +The thorax exhibits three radial ribs, which are completely enclosed in its +wall. Sethopera may be derived either from _Dictyophimus_ or from another +of the Sethopilida (_Lamprodiscus, Clathrocanium_) by development of a +basal lattice-plate closing the mouth. There are often wide holes or open +spaces between the three radial ribs. + + +1. _Sethopera tricostata_, n. sp. (Pl. 97, fig. 11). + +Cephalis subspherical, spinulate, with a pyramidal horn of the same length. +Length of the two joints = 5 : 8, breadth = 5 : 8. Thorax also nearly +spherical; in the upper half with three stout, prismatic, convex, divergent +ribs, and three large ovate holes between them; in the lower half with +numerous small and irregular pores, spinulate. + +_Dimensions._--Cephalis 0.05 diameter; thorax 0.08 diameter. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +2. _Sethopera oceania_, Haeckel. + + _Lithopera oceania_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 297, Taf. iv. fig. 21. + +Cephalis hemispherical, with a small bristle-shaped horn of half the length +(broken off in Ehrenberg's figure). Length of the two joints = 3 : 4, +breadth = 3 : 4. Thorax nearly spherical; in the upper half with three +divergent ribs, separated by some larger, irregular pores; in the lower +half with numerous small, irregular, roundish pores. + +_Dimensions._--Cephalis 0.03 long, 0.03 broad; thorax 0.04 long, 0.04 +broad. + +_Habitat._--North Atlantic, Station 354, surface; Canary Islands and +Azores. + + +3. _Sethopera pyrum_, Haeckel. + + ? _Lithopera pyrum_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 297. + +Cephalis hemispherical, with a small conical horn of half the length. +Length of the two joints = 3 : 10, breadth = 3 : 7. Thorax pear-shaped, +with rather large, regular, quincuncial pores; {1233}its upper half with +three divergent ribs in the wall, half as broad as the subspherical lower +half. (The three ribs probably were overlooked by Ehrenberg.) + +_Dimensions._--Cephalis 0.03 long, 0.03 broad; thorax 0.1 long, 0.07 broad. + +_Habitat._--North Pacific, Station 256, surface; Californian Sea, 2600 +fathoms, Ehrenberg. + + +4. _Sethopera lagena_, Haeckel. + + _Lithopera lagena_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 78, Taf. iii. fig. 4. + +Cephalis pear-shaped, with a small conical horn of half the length. Length +of the two joints = 3 : 8, breadth = 3 : 6. Thorax smooth, pear-shaped, +with irregular roundish pores; in the wall of its upper third three +divergent thin ribs (sometimes wanting); the lower half inflated. (Compare +_Sethocapsa lagena_.) + +_Dimensions._--Cephalis 0.03 long, 0.03 broad; thorax 0.08 long, 0.06 +broad. + +_Habitat._--Fossil in Barbados. + + + +Genus 551. _Lithopera_,[168] Ehrenberg, 1847, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 54. + +_Definition._--#Sethoperida# (vel Dicyrtida triradiata clausa), with three +divergent ribs enclosed in the cavity of the thorax. Cephalis with a horn. + +The genus _Lithopera_ is, like the preceding _Sethopera_, one of the most +simple and oldest forms of the Sethoperida, and exhibits three divergent +thoracic ribs, which are prolonged neither into lateral wings nor into +basal feet. But whilst in _Sethopera_ the three ribs are enclosed in the +lattice-work of the shell-wall, in _Lithopera_ they lie freely in its +cavity, and are overgrown by the enveloping shell-wall, being inserted on +its inner face with their distal ends. _Lithopera_ may be derived directly +from _Lithomelissa_, by development of lattice-work closing the +shell-mouth. Therefore the lower part of the cephalis is hidden in the +uppermost part of the thorax; only its upper part is free. + + +1. _Lithopera bacca_, Ehrenberg. + + _Lithopera bacca_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. Berlin, + p. 297, Taf. viii. fig. 1. + +Cephalis spherical, with small, irregular pores and a bristle-shaped spine +of half the length; its lower half hidden in the thorax. Length of the two +joints = 1 : 6, breadth = 1 : 5. Thorax ellipsoidal, smooth, with regular, +hexagonal, small pores, and very thin, thread-like bars. From the deep +collar stricture there arise three internal, divergent bars, which are +inserted at the uppermost third of the thorax. + +_Dimensions._--Cephalis 0.02 diameter; thorax 0.12 long, 0.1 broad. + +_Habitat._--Tropical Pacific, Stations 200, 224, 266, 271, &c., surface. + + +{1234}2. _Lithopera bursella_, Ehrenberg. + +_Lithopera bursella_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. +Berlin, p. 297, Taf. x. fig. 4. + +Shell of about the same form and structure as in the nearly allied +preceding species, but smaller, of more slender form, with smaller pores +and thinner bars. Length of the two joints = 1 : 5, breadth = 1 : 3. In the +specimen observed by me the three internal, divergent bars of the +ellipsoidal thorax (not seen by Ehrenberg) were as distinct as in the +similar preceding and following species. + +_Dimensions._--Cephalis 0.02 diameter; thorax 0.1 long, 0.06 broad. + +_Habitat._--Indian Ocean, Zanzibar (Pullen), Madagascar (Rabbe), surface. + + +3. _Lithopera ananassa_, n. sp. (Pl. 57, fig. 3). + +Shell of about the same form and structure as in the two preceding species, +but larger and more robust, and differing in the spiny surface. Length of +the two joints = 1 : 5, breadth = 1 : 4. Here also the lower half of the +spherical cephalis is submerged in the ellipsoidal thorax, and from the +collar stricture arise three strong, internal, divergent beams. The bars of +the hexagonal pores are much thicker than in the two preceding species. + +_Dimensions._--Cephalis 0.03 diameter; thorax 0.16 long, 0.12 broad. + +_Habitat._--Tropical Atlantic, Stations 347 to 352, surface. + + +4. _Lithopera globosa_, n. sp. + +Cephalis spherical, very small, with two divergent conical horns of half +the length; its lower half hidden in the thorax. Length of the two joints = +1 : 5, breadth = 1 : 5. Thorax spherical, with regular, circular, +hexagonally-framed pores. From the collar stricture arise three radial +internal beams, horizontally diverging, and inserted at the inside of the +thorax. + +_Dimensions._--Cephalis 0.03 diameter; thorax 0.15 diameter. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +5. _Lithopera gutta_, Ehrenberg. + + _Lithopera gutta_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. Berlin, + p. 297, Taf. viii. fig. 2. + +Shell pear-shaped, with sharp collar stricture. Length of the two joints = +1 : 4, breadth = 1 : 3. Cephalis spherical, with a conical horn of the same +length; its lower half hidden in the uppermost part of the ovate thorax, +and connected with its wall by three internal, cortinar beams. Pores of the +thorax very irregular in form and size, partly lobed. + +_Dimensions._--Cephalis 0.02 diameter; thorax 0.08 long, 0.06 broad. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms; +Philippine Sea (depth 3300 fathoms), Ehrenberg. + + + +{1235}Genus 552. _Micromelissa_,[169] Haeckel, 1881, Prodromus, p. 433. + +_Definition._--#Sethoperida# (vel Dicyrtida triradiata clausa), with three +divergent, solid, lateral wings. Cephalis with a horn. + +The genus _Micromelissa_ differs from the two preceding genera in the free +prominence of the three cortinar ribs, forming three solid lateral wings. +Beyond these the thorax walls are convergent, and the basal mouth closed by +a lattice-plate. Therefore _Micromelissa_ may have arisen from +_Lithomelissa_ simply by development of this basal mouth-plate. + + +1. _Micromelissa bombus_, n. sp. (Pl. 57, fig. 14). + +Shell smooth, with sharp collar stricture. Length of the two joints = +1 : 4, breadth = 1 : 5. Cephalis spherical, with an oblique conical horn of +the same length. Thorax subspherical, in the upper half with three conical, +downwardly diverging wings, about as long as its radius. Pores very small +and scarce. + +_Dimensions._--Cephalis 0.02 long, 0.02 broad; thorax 0.09 long, 0.1 broad. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +2. _Micromelissa vespa_, n. sp. + +Shell smooth, with deep collar stricture. Length of the two joints = 2 : 5, +breadth = 2 : 3. Cephalis spherical, with an oblique pyramidal horn twice +the length. Thorax inversely ovate, in the upper half with three pyramidal +wings, which are equal to its breadth, little curved and diverging +downwards. Pores very small and scarce. + +_Dimensions._--Cephalis 0.04 diameter; thorax 0.1 long, 0.06 broad. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +3. _Micromelissa apis_, n. sp. + +Shell rough, with deep collar stricture. Length of the two joints = 2 : 3, +breadth = 2 : 4. Cephalis subspherical, with a straight conical horn of +half the length, and subregular, circular, double-contoured pores, of the +same breadth as the bars. Thorax little larger, subspherical, with +irregular, roundish pores, twice to four times as broad as the bars. From +its lower half arise three short conical wings, curved downwards, and half +as long as the cephalis. + +_Dimensions._--Cephalis 0.04 long, 0.04 broad; thorax 0.06 long, 0.08 +broad. + +_Habitat._--South Pacific, Station 295, depth 1500 fathoms. + + +{1236}4. _Micromelissa microptera_, Haeckel. + + _Lithomelissa microptera_, Ehrenberg, 1854, Mikrogeol., Taf. xxxvi. fig. + 2; Abhandl. d. k. Akad. d. Wiss. Berlin, 1875, p. 78, Taf. iii. fig. 13. + + _Lithomelissa microptera_, Buetschli, 1882, Zeitschr. f. wiss. Zool., + vol. xxxvi. p. 539, Taf. xxxiii. fig. 26. + +Shell smooth, with distinct collar stricture. Length of the two joints = +4 : 6, breadth = 3 : 5. Cephalis ovate, with a straight sword-shaped horn +of the same length and very small pores, some larger ones above the +stricture. Thorax little larger, ovate, nearly hyaline, with very few and +small scattered pores. From its uppermost part arise three short conical +wings, scarcely half as long as the cephalic horn, little curved and +divergent downwards. + +_Dimensions._--Cephalis 0.04 long, 0.03 broad; thorax 0.06 long, 0.05 +broad. + +_Habitat._--Fossil in Barbados. + + +5. _Micromelissa ventricosa_, Haeckel. + + _Lithomelissa ventricosa_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 78, Taf. iii. fig. 11. + +Shell rough, with slight collar stricture. Length of the two joints = +1 : 7, breadth = 1 : 5. Cephalis small, hemispherical, with a small conical +horn of half the length. Thorax ovate, very large, papillate, with +irregular, roundish pores. From its basal part arise three short and stout +conical wings at great distances, shorter than the cephalis. (A +transition-form to _Sethocapsa_.) + +_Dimensions._--Cephalis 0.02 long, 0.022 broad; thorax 0.14 long, 0.11 +broad. + +_Habitat._--Fossil in Barbados. + + + +Genus 553. _Peromelissa_,[170] Haeckel, 1881, Prodromus, p. 433. + +_Definition._--#Sethoperida# (vel Dicyrtida triradiata clausa) with three +divergent solid lateral wings. Cephalis without horn. + +The genus _Peromelissa_ differs from the preceding ancestral form, +_Micromelissa_, only in the absence of the cephalic horn, which is lost by +reduction. + + +1. _Peromelissa phalacra_, n. sp. (Pl. 57, fig. 11). + +Shell smooth, with two joints of nearly equal size and similar ovate form. +Cephalis in the upper half hyaline, without pores; in the lower half with +four remote, transverse rows of irregular, roundish pores, decreasing in +size towards the hemispherical summit. Thorax with twelve transverse +{1237}rows of pores, the upper six rows three to four times as large as the +lower six rows. From its upper half diverge almost horizontally three +angular club-shaped wings, half as long as the shell. + +_Dimensions._--Cephalis 0.05 long, 0.06 broad; thorax 0.06 long, 0.05 +broad. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +2. _Peromelissa psilocrana_, n. sp. + +Shell smooth, very similar to the preceding species in size and form, but +differing from it in the disposition of the irregular, roundish pores, +which are irregularly scattered, and in the form of the three wings, which +are slender, pyramidal, diverging downwards, and about as long as the +entire shell. + +_Dimensions._--Cephalis 0.07 long, 0.06 broad; thorax 0.07 long, 0.06 +broad. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +3. _Peromelissa capito_, Haeckel. + + _Lithomelissa capito_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 78, Taf. iii. fig. 14. + +Shell rough, with two joints of nearly equal size and similar ovate form. +Pores irregular, roundish, everywhere scattered. From the upper half of the +thorax arise three short conical wings, which are little curved and diverge +downwards (scarcely half as long as the breadth of the shell). + +_Dimensions._--Cephalis 0.07 long, 0.06 broad; thorax 0.07 long, 0.06 +broad. + +_Habitat._--Fossil in Barbados. + + +4. _Peromelissa calva_, n. sp. (Pl. 57, fig. 12). + +Shell rough, with two ovate joints of somewhat different sizes. Pores +irregular, roundish, everywhere scattered. Thorax little larger than the +cephalis; from its upper half arise three short conical wings, diverging +downwardly or nearly horizontally. + +_Dimensions._--Cephalis 0.06 long, 0.04 broad; thorax 0.07 long, 0.05 +broad. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + + +Genus 554. _Sethomelissa_,[171] Haeckel, 1881, Prodromus, p. 431. + +_Definition._--#Sethoperida# (vel Dicyrtida triradiata clausa) with three +divergent latticed lateral wings. Cephalis with a horn (or a bunch of +horns). + +The genus _Sethomelissa_ differs from the nearly allied _Micromelissa_ in +the fenestration of the three lateral wings, and may be derived either from +this genus by development of lattice-work connecting the three wings with +the shell, or perhaps from _Clathrocanium_ by closing the mouth. + + +{1238}1. _Sethomelissa hymenoptera_, n. sp. + +Cephalis subspherical, thorny, with a bunch of three divergent, larger +apical spines. Thorax pear-shaped, with three broad, triangular, latticed +wings, the superior edge of which is a horizontal, straight, and stout +spine, nearly as long as the thorax. Pores irregular, roundish. + +_Dimensions._--Cephalis 0.03 diameter; thorax 0.11 long, 0.08 broad. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +Genus 555. _Tetrahedrina_,[172] Haeckel, 1881, Prodromus, p. 433. + +_Definition._--#Sethoperida# (vel Dicyrtida triradiata clausa) with a +three-sided pyramidal thorax, the three edges of which are prolonged into +three divergent, solid, terminal feet. Cephalis with a horn. + +The genus _Tetrahedrina_, and the two following nearly allied genera, are +distinguished by the possession of three free, divergent, terminal feet, +projecting over the latticed mouth of the thorax. _Tetrahedrina_ may be +derived directly from _Dictyophimus_, by development of a horizontal +latticed mouth-plate from the middle part of the feet, the lower part of +which remains free. This genus, not noticed by Ehrenberg, is similar to his +_Lithochytris_, and common in the Barbados deposits. + + +1. _Tetrahedrina pyramidalis_, n. sp. + +Shell three-sided pyramidal, smooth, with slight collar stricture. Length +of the two joints = 1 : 4, breadth = 1 : 4. Cephalis hemispherical, with +small, sparsely disposed pores, and a pyramidal horn of the same length. +Thorax with subregular, circular pores and three sharp edges, prolonged +into three divergent pyramidal feet of the same length. + +_Dimensions._--Cephalis 0.03 diameter; thorax 0.12 long, 0.12 broad. + +_Habitat._--Fossil in Barbados. + + +2. _Tetrahedrina pyriformis_, n. sp. + +Shell pear-shaped, rough, with distinct collar stricture. Length of the two +joints = 2 : 6, breadth = 2 : 5. Cephalis subspherical, with a conical horn +of the same length. Thorax with subregular, circular pores, ovate, at the +broad base with three pyramidal, widely divergent feet of the same length. +(Similar to _Lychnocanium tribulus_, Ehrenberg, 1875, _loc. cit._, pl. vii. +fig. 1, but with the mouth closed by a lattice-plate.) + +_Dimensions._--Cephalis 0.04 diameter; thorax 0.12 long, 0.1 broad, + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +{1239}3. _Tetrahedrina quadricornis_, Haeckel. + + _Lithochytris triangula_, Bury, 1862, Polycystins of Barbados, pl. xix. + figs. 4, 5, 6. + +Shell pear-shaped, papillate, with slight collar stricture. Length of the +two joints = 1 : 5, breadth = 1 : 5. Cephalis subspherical, with a stout +conical horn twice the length. Thorax with irregular, roundish, lobulated +pores, with three conical, stout, divergent feet at the base, of the same +size and form as the cephalic horn. + +_Dimensions._--Cephalis 0.02 diameter; thorax 0.1 long, 0.1 broad. + +_Habitat._--Fossil in Barbados. + + + +Genus 556. _Sethochytris_,[173] Haeckel, 1881, Prodromus, p. 433. + +_Definition._--#Sethoperida# (vel Dicyrtida triradiata clausa) with three +terminal latticed feet or hollow, fenestrated, divergent, basal apophyses +of the thorax. Cephalis with a horn. + +The genus _Sethochytris_ differs from the preceding _Tetrahedrina_ in the +fenestration of the three basal feet, which form direct protrusions or +evaginations of the three basal corners of the pyramidal shell. It may be +derived from _Sethopera_ by centrifugal growth of the basal corners. + + +1. _Sethochytris triconiscus_, n. sp. (Pl. 57, fig. 13). + +Shell rough, with deep collar stricture. Length of the two joints = 1 : 8, +breadth = 1 : 3. Cephalis spherical, with an oblique pyramidal horn of the +same length. Thorax campanulate, conical; its three basal corners prolonged +into three divergent, slender, hollow, fenestrated cones, twice as long as +the thorax, and ending in a stout pyramidal spine. + +_Dimensions._--Cephalis 0.04 diameter, thorax 0.12 diameter, length of the +feet 0.2. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +2. _Sethochytris barbadensis_, Haeckel. + + _Lithochytris barbadensis_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 160, Taf. v. fig. 2. + +Shell smooth, with slight collar stricture. Length of the two joints = +1 : 6, breadth = 1 : 4. Cephalis ovate, with a conical horn of half the +length. Thorax conical; its base prolonged into three divergent, hollow, +fenestrated cones, half as long as the thorax. Pores small, subregular, +circular. + +_Dimensions._--Cephalis 0.025 diameter, thorax 0.1 diameter, length of the +feet 0.05. + +_Habitat._--Fossil in Barbados. + + +{1240}3. _Sethochytris pyramis_, n. sp. + +Shell smooth, with slight collar stricture. Length of the two joints = +1 : 8, breadth = 1 : 5. Cephalis ovate, with a conical horn of half the +length. Thorax pyramidal, with three sharp edges; its base prolonged into +three pyramidal, divergent, hollow, fenestrated feet, nearly as long as the +thorax. Pores regular, circular, double-contoured. + +_Dimensions._--Cephalis 0.04 diameter; thorax 0.2 diameter, length of the +feet 0.15. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms; also fossil +in Barbados. + + +4. _Sethochytris triangula_, Haeckel. + + _Lithochytris triangula_, Bury, 1862, Polycystins of Barbados, pl. xix. + fig. 7. + +Shell rough, with obliterated collar stricture (but distinct internal +collar septum). Length of the two joints = 1 : 6, breadth = 1 : 3. Cephalis +subspherical, with a stout conical horn of the same length. Thorax +pear-shaped, inflated; its base prolonged into three divergent, hollow, +fenestrated cones, about as long as the thorax. Pores regular, circular. + +_Dimensions._--Cephalis 0.03 diameter; thorax 0.09 diameter, length of the +feet 0.1. + +_Habitat._--Fossil in Barbados. + + + +Genus 557. _Clathrolychnus_,[174] Haeckel, 1881, Prodromus, p. 431. + +_Definition._--#Sethoperida# (vel Dicyrtida triradiata clausa), with three +vertical, lateral latticed wings stretched between the apical horn and the +three terminal feet. The external lattice-work connecting the wings and +closing the mouth forms an arachnoidal mantle around the shell. + +The genus _Clathrolychnus_ may be derived directly from _Clathrocorys_, by +development of an external arachnoidal mantle connecting the three wings +and the three feet, and enveloping the whole shell, closing at the same +time the basal mouth of the thorax by a fenestrated plate. + + +1. _Clathrolychnus araneosus_, n. sp. (Pl. 64, fig. 5). + +Cephalis subspherical, with irregular, polygonal pores and a large +pyramidal horn of twice the length. Length of the two joints = 4 : 9, +breadth = 5 : 12. Thorax with three large triangular holes (twice as broad +as the cephalis) between the three pyramidal, divergent feet, which at the +distal end are connected by a narrow band of network, composed of two or +three rows of polygonal pores. The entire pyramidal shell is enveloped by a +very delicate web of irregular, polygonal {1241}meshes, closing also the +basal mouth. (In fig. 5 the greater part of the web is taken off to +demonstrate the large holes of the thorax). Only two feet are visible. + +_Dimensions._--Cephalis 0.04 long, 0.05 broad; thorax 0.09 long, 0.12 +broad. + +_Habitat._--Central Pacific, Station 274, surface. + + +2. _Clathrolychnus periplectus_, n. sp. (Pl. 64, fig. 6). + +Cephalis subspherical, with subregular, circular pores and a pyramidal horn +of the same length. Length of the two joints = 1 : 2, breadth = 1 : 3. +Thorax with three large elliptical holes between the three pyramidal, +divergent feet, which are connected at the distal end by a broad band of +network, composed of five to ten rows of polygonal pores. The entire +pyramidal shell is enveloped by a very delicate web, which on the sides is +composed of subregular, square meshes, and on the closed mouth of polygonal +meshes. (In fig. 6 only a part of the web is represented.) + +_Dimensions._--0.04 long, 0.05 broad; thorax 0.08 long, 0.14 broad. + +_Habitat._.--Central Pacific, Station 271, surface. + + + +Family LXIII. #ANTHOCYRTIDA#, n. fam. + + _Sethophormida et Sethophaenida_, Haeckel, 1881, Prodromus, p. 432, 433. + +_Definition._--#Dicyrtida# multiradiata. (#Cyrtoidea# with a two-jointed +shell, divided by a transverse constriction into cephalis and thorax, and +bearing numerous--four to nine or more--radial apophyses.) + +The family #Anthocyrtida#, composed of the Sethophormida and Sethophaenida +of my Prodromus, comprises those #Cyrtoidea# in which the shell is +two-jointed and bears numerous radial apophyses. The two subfamilies differ +in the shape of the mouth, which in the Sethophormida is a simple, wide +opening; in the Sethophaenida closed by a lattice-plate. + +Numerous fossil and living forms of Anthocyrtida were described formerly by +Ehrenberg in his genera _Carpocanium_ and _Anthocyrtis_. These, however, +represent only a small part of the whole family, which exhibits a great +variety in the composition of the lattice-work and in the number of radial +beams. The number of species here described amounts to one hundred and +forty, and these are disposed in fourteen genera (twelve Sethophormida and +two Sethophaenida). + +The Sethophormida may be again divided into two different groups or tribes, +the _Sethamphorida_ and _Carpocanida_; in the former the thorax bears +numerous radial ribs, enclosed in its wall; in the latter these ribs have +disappeared, and only a corona of terminal feet is developed around the +mouth. The shell of the former is usually pyramidal, with a widely open +mouth; of the latter ovate, with a constricted mouth. The mouth of the +thorax becomes perfectly closed in the Sethophaenida. + +{1242}The majority of the Anthocyrtida may be derived from the Polyspyrida +(_Petalospyris_, &c.) by reduction of the cephalis and loss of the sagittal +ring, as was suggested by Buetschli (1882, _loc. cit._). But another part +may also have arisen from the Tripocyrtida, by interpolation of secondary +radial apophyses between the three primary perradial apophyses. The +cephalis in this family is developed in all possible degrees, from one of a +considerable size to one very much reduced. If it becomes perfectly lost, +the Cyrtocalpida arise. + +_Synopsis of the Genera of Anthocyrtida._ + + ------------------------------------------------------------------------- + I. Subfamily Sethophormida. + Terminal mouth of the thorax a simple wide opening. + -------------------- + Radial ribs thorny (rarely smooth) prolonged into free terminal feet + (cephalis commonly large, with one or more horns). + ------------------------------------------------------------------------- + Shell flat, campanulate or nearly discoidal + (cephalis without horn), 558. _Sethophormis_. + + Shell ovate, with constricted mouth + (without horn), 559. _Sethamphora_. + + { Meshes of the network simple, 560. _Sethopyramis_. + { + Shell slender { Meshes fenestrated by + pyramidal, with { secondary latticework, 561. _Plectopyramis_. + straight ribs. { + { Meshes closed by spongy + { framework, 562. _Spongopyramis_. + ------------------------------------------------------------------------- + Radial ribs thorny (rarely smooth) prolonged into free terminal feet + (cephalis commonly large, with one or more horns). + ------------------------------------------------------------------------- + Shell not enveloped by arachnoidal network, 563. _Acanthocorys_. + + Shell enveloped by arachnoidal network, 564. _Arachnocorys_. + ------------------------------------------------------------------------- + No ribs in the thorax. Peristome with free terminal feet. + ------------------------------------------------------------------------- + { { Six feet, 565. _Anthocyrtoma_. + { Feet { + { terminal, { Nine feet, 566. _Anthocyrtis_. + Cephalis { without { + well-developed { separate { Twelve or more + with an apical { peristome. { feet, 567. _Anthocyrtium_. + horn. { + { Feet subterminal, outside the + { constricted peristome, 568. _Anthocyrtidium_. + + Cephalis rudimentary, hidden in the upper + part of the thorax, without horn, 569. _Carpocanium_. + ------------------------------------------------------------------------- + II. Subfamily Sethophaenida. Terminal mouth closed by a lattice-plate. + ------------------------------------------------------------------------- + Thorax with lateral apophyses (four to six or + more wings), 570. _Sethophaena_. + + Thorax with terminal apophyses (four to six or + more feet), 571. _Clistophaena_. + + + +{1243}Subfamily 1. SETHOPHORMIDA, Haeckel, 1881, Prodromus, p. 432. + +_Definition._--#Anthocyrtida# with the basal mouth of the shell open (vel +Dicyrtida multiradiata aperta). + + + +Genus 558. _Sethophormis_, Haeckel,[175] 1881, Prodromus, p. 432. + +_Definition._--#Sethophormida# (vel Dicyrtida multiradiata aperta) with +numerous radial ribs in the wall of the flat and broad campanulate or +nearly discoidal thorax. Cephalis also flat and broad, cap-shaped without +horn. + +The genus _Sethophormis_ comprises a great number of widely distributed and +large Dicyrtida, all agreeing in the flat cap-shaped or nearly discoidal +form of the thorax, which has constantly a very delicate network, and is +pierced by numerous radial beams. Four of these are commonly primary and +direct prolongations of the four cortinar rods in the collar septum, whilst +the others are secondary or interpolated ribs. _Sethophormis_ may be +derived either from the triradial _Lamprodiscus_ by multiplication of the +ribs (or interpolation of secondary ribs between the three primary), or +from _Halicalyptra_ by development of transverse rods connecting its +terminal feet, and forming a ribbed thorax. Corresponding to the number of +the ribs, we may distinguish as subgenera (separate genera in my Prodromus, +1881, p. 432) _Tetraphormis_ with four, _Pentaphormis_ with five, +_Hexaphormis_ with six, _Octophormis_ with eight, _Enneaphormis_ with nine, +and _Astrophormis_ with ten to twenty or more ribs. The cephalis bears no +horn, and is usually large, flat, cap-shaped or hemispherical. + + + +Subgenus 1. _Tetraphormis_, Haeckel, 1881, Prodromus, p. 432. + +_Definition._--Thorax with four radial ribs opposite in pairs in two +meridional planes, perpendicular to one another. Collar septum with four +large pores. + + +1. _Sethophormis cruciata_, n. sp. + +Cephalis very large, hemispherical with irregular, delicate network of +small square meshes. Thorax flatly campanulate, with delicate, regular +network of small hexagonal meshes. All bars very thin, thread-like. Four +stout radial thoracic ribs, crossed in pairs, lie in two meridional planes, +perpendicular to one another. Very similar to _Sethophormis aurelia_ (Pl. +55, figs. 3, 4), but not so flat, and with only four thoracic ribs. +Peristome or margin of the thoracic mouth smooth, circular. + +_Dimensions._--Cephalis 0.04 long, 0.08 broad; thorax 0.12 long, 0.36 +broad. + +_Habitat._--Central Pacific, Station 271, surface. + + +{1244}2. _Sethophormis medusa_, n. sp. + +Cephalis very large, flat, cap-shaped, with irregular, delicate network of +polygonal meshes. Thorax flat, campanulate, nearly hemispherical, with +delicate, irregular network of small polygonal meshes. All bars very thin, +thread-like. Four stout radial thoracic ribs, as in the preceding species. +Peristome denticulate. + +_Dimensions._--Cephalis 0.03 long, 0.09 broad; thorax 0.15 long, 0.25 +broad. + +_Habitat._--North Pacific, Station 244, surface. + + + +Subgenus 2. _Pentaphormis_, Haeckel, 1881, Prodromus, p. 432. + +_Definition._--Thorax with five radial ribs, one of the three primary ribs +(the odd occipital rib) being simple, the two others (the paired lateral +ribs) forked. + + +3. _Sethophormis pentalactis_, n. sp. (Pl. 56, fig. 5). + +Cephalis large, flat, hemispherical, with subregular, hexagonal pores. +Thorax flat, campanulate, nearly hemispherical; also with subregular, +hexagonal pores, and with five stout ribs. The three primary ribs of the +thorax are complete, and reach the peristome; the two secondary ribs (as +basal branches of the two lateral ribs) are incomplete and absent in the +distal half of the thorax. Peristome denticulate, with an elegant marginal +corona of small square pores and short conical spines. + +_Dimensions._--Cephalis 0.03 long, 0.06 broad; thorax 0.1 long, 0.2 broad. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +4. _Sethophormis asteriscus_, n. sp. + +Cephalis large, flat, cap-shaped, with irregular polygonal pores. Thorax +flat, campanulate, with subregular, hexagonal pores, and five stout ribs. +The marginal distance between the two anterior (lateral) ribs is twice as +great as the distance between every two other ribs (the postero-lateral +ribs being basal branches of the antero-lateral ribs). Peristome with a +double corona of short, conical spines. + +_Dimensions._--Cephalis 0.02 long, 0.04 broad; thorax 0.06 long, 0.17 +broad. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +5. _Sethophormis astrodiscus_, n. sp. + +Cephalis small, flatly vaulted, cap-shaped with irregular polygonal pores. +Thorax very flatly vaulted, nearly discoidal, with subregular hexagonal +pores, and five stout ribs. The marginal distance between all five ribs is +nearly equal. Peristome denticulate with an elegant corona of small square +pores and short conical thorns. + +_Dimensions._--Cephalis 0.015 long, 0.035 broad; thorax 0.05 long, 0.2 +broad. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms. + + + +{1245}Subgenus 3. _Hexaphormis_, Haeckel, 1881, Prodromus, p. 432. + +_Definition._--Thorax with six radial ribs (three primary perradial and +three secondary interradial beams). + + +6. _Sethophormis hexalactis_, n. sp. (Pl. 56, fig. 6). + +Cephalis large, hemispherical, with irregular, polygonal pores. Thorax +flatly campanulate, with subregular, hexagonal pores, and six stout radial +ribs; the lateral connected in pairs. (Fig. 6 exhibits the central part of +the shell, seen from below.) In the subcircular collar septum the two +anterior (jugular) meshes are much smaller than the two posterior +(cardinal) meshes. The odd anterior (sternal) rib is opposite to the +posterior (caudal) rib. The two paired ribs of each side (antero-lateral or +pectoral and postero-lateral or ventral ribs) diverge from one common +point. In the specimen figured the left half of the thorax exhibited the +two regular ribs, and the right half three, a posterior accessory branch +being developed (transition to _Octophormis_). This specimen might indeed +be called _Heptaphormis heptalactis_. + +_Dimensions._--Cephalis 0.02 long, 0.05 broad; thorax 0.08 long, 0.22 +broad. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + +7. _Sethophormis hexagonalis_, n. sp. + +Cephalis small, flat, cap-shaped, with small, regular, hexagonal pores. +Thorax flatly conical, nearly discoidal, with larger pores of the same +form, and six stout, straight, prominent ribs. These arise at equal +distances from the six corners of the hexagonal base of the collar septum. +Peristome hexagonal, with a corona of short spines. + +_Dimensions._--Cephalis 0.015 long, 0.04 broad; thorax 0.06 long, 0.24 +broad. + +_Habitat._--North Atlantic, Station 354, surface. + + + +Subgenus 4. _Octophormis_, Haeckel. + +_Definition._--Thorax with eight radial ribs, four secondary interradial +beams being interpolated between the four primary perradial beams of +_Tetraphormis_. + + +8. _Sethophormis octalactis_, n. sp. + +Cephalis large, hemispherical, with irregular, polygonal pores. Thorax +flatly campanulate, with regular, hexagonal pores, and eight stout, +regularly-disposed, radial ribs reaching the margin at equal distances. +Four of these correspond to the four primary ribs of _Tetraphormis +cruciata_, and exhibit at their base a larger pair of basal pores, +surrounded by a semicircular ring (Pl. 70, fig. 5); the other four are +secondary, interpolated. Peristome circular, simple. + +_Dimensions._--Cephalis 0.03 long, 0.06 broad; thorax 0.1 long, 0.22 broad. + +_Habitat._--Indian Ocean, Madagascar (Rabbe), surface. + + + +{1246}Subgenus 5. _Enneaphormis_, Haeckel, 1881, Prodromus, p. 432. + +_Definition._--Thorax with nine radial ribs, three of which are the primary +beams, the other six being secondary and interpolated. + + +9. _Sethophormis rotula_, n. sp. (Pl. 57, fig. 9). + + _Enneaphormis rotula_, Haeckel, 1881, Prodromus et Atlas, pl. lvii. fig. + 9. + +Cephalis very large, flat, cap-shaped, trilobed, with irregular, polygonal +network. Horizontal collar-ring stout, hexagonal, with three larger and +three alternate smaller sides of half the length. From the middle of the +three larger sides arise three horizontal, centripetal, radial beams, which +are united in the centre of the collar-septum--the three primary cortinar +beams. These are prolonged outside into three centrifugal primary ribs of +the thorax. From the six corners of the collar-ring arise six other +secondary, thoracic ribs, equal in size and similar in form to the three +primary. Each of these nine equal, straight ribs of the thorax is thickened +towards the distal end, and bears at equal distances five pairs of opposite +(tangential) lateral branches. The opposite branches of the neighbouring +spines become united, and lie nearly horizontally in one plane, so that the +flat, discoidal thorax is like a nine-angled wheel with nine equally +distant spokes and five concentric, nine-angled rings. + +_Dimensions._--Cephalis 0.12 diameter, thorax 0.36 diameter. + +_Habitat._--Central Pacific, Stations 270 to 274, depth 2350 to 2925 +fathoms. + + +10. _Sethophormis triloba_, n. sp. + +Cephalis large, hemispherical, distinctly trilobed, with dense, irregular, +polygonal network. From the centre of its top diverge three stout arches or +semilunar rods, which are curved downwards, and unite with the three +horizontal, radial beams of the collar-septum inside the collar-ring. These +three parietal arches of the cephalis are much stronger than in the similar +preceding species (Pl. 57, fig. 9), and between them are placed three +vaulted bosoms of the cephalis. The collar-ring and the thorax are of the +same form as in the preceding, but possess only four concentric, +nine-angled rings. + +_Dimensions._--Cephalis 0.05 long, 0.08 broad; thorax 0.24 diameter. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +11. _Sethophormis enneastrum_, n. sp. + +Cephalis very large, flat, cap-shaped, with hexagonal base, trilobed, of +similar form and structure to the two preceding species. The flat, +discoidal thorax has also the same form, with nine stout ribs and five +concentric, nine-angled rings; its forty-five large meshes, however, are +not so simple {1247}as these (Pl. 57, fig. 9), but are subdivided into +irregular, smaller meshes by interpolated radial beams connecting the +concentric rings. + +_Dimensions._--Cephalis 0.1 diameter, thorax 0.3 diameter. + +_Habitat._--North Pacific, Station 253, depth 3125 fathoms. + + +12. _Sethophormis arachnium_, n. sp. + +Cephalis very large, flat, cap-shaped, trilobed, with hexagonal base, of +the same structure as in the three preceding species. The flat discoidal +thorax is also similar, and has the same structure as in the preceding +species (Pl. 57, fig. 9); but the number of concentric, nine-angled rings +is raised from five to eight, and in its outer part nine secondary radial +beams are interpolated between the nine primaries, so that the peristome +has not nine but eighteen corners. + +_Dimensions._--Cephalis 0.08 diameter, thorax 0.4 diameter. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +13. _Sethophormis enneactis_, n. sp. + +Cephalis small, hemispherical, with small, irregular, polygonal pores. +Thorax flatly pyramidal, nearly discoidal, with nine prominent, stout ribs, +which are connected by numerous (twelve to sixteen) horizontal, nine-angled +rings. In the outer half of the thorax there are nine weaker secondary ribs +interpolated between the nine stronger primaries, and eighteen shorter and +feebler tertiary ribs between the former and the latter. Peristome +denticulated, nine-angled. + +_Dimensions._--Cephalis 0.03 diameter, thorax 0.08 long, 0.24 broad. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +14. _Sethophormis eupilium_, n. sp. (Pl. 56, fig. 9). + + Sethopyramis eupilium, Haeckel, 1882, Atlas, pl. lvi. fig. 9. + + Craspedilium eupilium, Haeckel, 1878, Manuscript. + +Cephalis very small, hemispherical, hyaline, without pores. Thorax flatly +pyramidal, with nine concave, triangular faces and nine little curved, +stout, radial beams. Between these are interpolated numerous incomplete +secondary beams, which are absent in the apical part of the thorax. The +radial beams being connected by numerous (thirty to forty or more) +horizontal, ring-like threads, a delicate arachnoidal network with small, +quadrangular pores is produced. Peristome nine-angled, with a peculiar +vertical gallery, composed of four horizontal, parallel, nine-angled rings, +which are connected by numerous vertical, parallel bars, therefore with +three transverse rows of square pores. This peculiar species is very +different from the preceding and may represent a separate genus, +_Craspedilium_. + +_Dimensions._--Cephalis 0.01 diameter, thorax 0.1 long, 0.25 broad. + +_Habitat._--Central Pacific, Station 271, surface. + + + +{1248}Subgenus 6. _Astrophormis_, Haeckel. + +_Definition._--Thorax with a variable number of radial ribs (twelve to +twenty or more). + + +15. _Sethophormis aurelia_, n. sp. (Pl. 55, figs. 3, 4). + + _Leptarachnium aurelia_, Haeckel, 1879, Manuscript et Atlas. + +Cephalis large, nearly hemispherical, with irregular, delicate network of +small square meshes. Collar-septum with four large meshes, separated by a +cross of four bars, opposite in pairs. Thorax flatly campanulate, with +delicate, subregular, hexagonal meshes, and twenty-four prominent radial +ribs; four of these are primary or perradial (centrifugal prolongations of +the four bars of the collar-septum); four others are interradial or +secondary, alternating with the former at angles of 45d; sixteen others are +adradial or tertiary, interpolated between the first and second more or +less irregularly. In some specimens the disposition of the twenty-four ribs +was more regular, in others more irregular, than in the specimen figured +(figs. 3, 4). The central capsule (fig. 4) exhibits a flat, cap-shaped part +with the nucleus (enclosed in the cephalis), and four large, pear-shaped +lobes protruded through the four large collar holes (somewhat deformed in +the preparation figured). The wall of the thorax exhibits at the base four +larger, nearly semicircular pores, bisected by the four primary thoracic +ribs. Peristome with twenty-four indentations (between the prominent distal +ends of the twenty-four ribs), often more distinct than in the specimen +figured. + +_Dimensions._--Cephalis 0.03 long, 0.08 broad; thorax 0.1 to 0.2 long, 0.4 +to 0.6 broad. + +_Habitat._--Central Pacific, Station 263 to 274, depth 2350 to 2925 +fathoms. + + +16. _Sethophormis dodecaster_, n. sp. (Pl. 56, fig. 12). + +Cephalis small, flatly cap-shaped, with irregular, small, roundish pores. +Thorax flatly conical, nearly of the same shape as in the preceding +species, but only with twelve prominent ribs; four primary or perradial +ribs (as prolongations of the four crossed cortinar bars), and eight +adradial ribs interpolated between the former, and arising at some distance +from the collar ring. Peristome with twelve prominent pointed lobes +(supported by the distal ends of the twelve ribs), and with twelve +semicircular bosoms between them. (The specimen figured is young and not +fully developed.) + +_Dimensions._--Cephalis 0.02 long, 0.04 broad; thorax 0.1 long, 0.3 broad. + +_Habitat._--South Pacific, Station 298, depth 2225 fathoms. + + +17. _Sethophormis umbrella_, n. sp. (Pl. 70, figs. 4, 5). + +Cephalis large, flatly cap-shaped, with irregular, small polygonal meshes. +Thorax flat, umbrella-shaped, with subregular, hexagonal meshes, and +sixteen strong radial ribs. Four of these are perradial, and centrifugal +prolongations of the four crossed collar beams; four others are +interradial, and {1249}arise, alternating with the former, directly from +the horizontal collar ring; eight ribs are adradial or tertiary, and arise +in pairs from the four large perradial basal arches of the thorax, which +become bisected by the four primary ribs. Peristome irregularly +denticulate. + +_Dimensions._--Cephalis 0.02 long, 0.06 broad; thorax 0.12 long, 0.32 +broad. + +_Habitat._--North Pacific (off Japan), Stations 236 to 239, surface. + + +18. _Sethophormis floscula_, n. sp. + +Cephalis small, hemispherical, with subregular, small hexagonal pores. +Thorax flatly conical, with larger hexagonal meshes and twenty-four ribs; +four of these are perradial and prolongations of the four collar bars; four +interradial arise from the collar ring between the former, alternating with +them. Each of these eight main ribs gives off two more or less irregular, +lateral branches (one at each side), altogether sixteen. The thorax is +similar to _Cladarachnium ramosum_ (Pl. 55, fig. 5), whilst the cephalis is +quite different. Peristome with twenty-four prominent triangular lobes. + +_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.1 long, 0.4 broad. + +_Habitat._--South Atlantic, Station 325, surface. + + +19. _Sethophormis leptoscenium_, n. sp. + +Cephalis very small, spherical, with few small, circular pores. Thorax +flatly conical or tent-shaped, with concave lateral outlines, small +hexagonal meshes, and numerous (thirty to forty or more) strong, little +curved, simple radial ribs. Peristome nearly circular, with a corona of +small, irregular, conical spines. + +_Dimensions._--Cephalis 0.015 diameter; thorax 0.07 long, 0.26 broad. + +_Habitat._--Indian Ocean, Madagascar (Rabbe), surface. + + +20. _Sethophormis leptopilium_, n. sp. + +Cephalis very small, subspherical, hyaline, without pores. Thorax flatly +conical or hat-shaped, with concave lateral outlines, and a very delicate +network of small square meshes (similar to _Litharachnium araneosum_, Pl. +55, fig. 8). This is supported by thirty-two curved radial ribs, four of +which are primary, four secondary, and the other twenty-four interpolated. +Peristome horizontally expanded and little recurved, like the reflexed brim +of a hat. + +_Dimensions._--Cephalis 0.12 diameter; thorax 0.08 long, 0.24 broad. + +_Habitat._--South Pacific, Station 291, depth 2250 fathoms. + + + +Genus 559. _Sethamphora_,[176] n. gen. + +_Definition._--#Sethophormida# (vel Dicyrtida multiradiata aperta) with +numerous curved ribs in the wall of the ovate thorax, the small mouth of +which is constricted. Cephalis without horn. + +{1250}The genus _Sethamphora_ differs from the preceding _Sethophormis_, +and from the next following ribbed Sethophormida, mainly in the small, more +or less constricted mouth; therefore the thorax is more or less ovate, and +its ribs curved, with the convexity external. Sethophormis may be divided +into two different subgenera, _Dictyoprora_ and _Cryptocephalus_; in the +former the cephalis is perfectly free and well developed, in the latter it +is more or less hidden in the uppermost part of the thorax (like +_Carpocanium_). + + + +Subgenus 1. _Dictyoprona_, Haeckel, 1881, Prodromus, p. 430. + +_Definition._--Cephalis large, perfectly free, not hidden in the thorax. + + +1. _Sethamphora hexapleura_, n. sp. + +Shell ovate, smooth, with distinct collar stricture. Length of the two +joints = 3 : 11, breadth = 5 : 10. Cephalis large, free, hemispherical, +with small circular pores. Thorax truncate, ovate, with six strong curved +ribs, and six large triangular meshes between them in the upper half; five +smaller pores between every two ribs in the lower half (in three tiers); +therefore, together, thirty-six thoracic meshes. Mouth strongly +constricted, smooth, only one-third as broad as the thorax. + +_Dimensions._--Cephalis 0.03 long, 0.05 broad; thorax, 0.11 long, 0.1 +broad. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +2. _Sethamphora enneapleura_, n. sp. + +Shell subovate, smooth, with slight collar stricture. Length of the two +joints = 3 : 9, breadth = 4 : 8. Cephalis large, hemispherical, free, with +small circular pores. Thorax inflated, ovate, with nine strong curved ribs, +which are connected by five transverse circular rings at equal distances. +Forty-five rounded, squarish, large meshes between them, in five transverse +and nine longitudinal rows. Mouth constricted, smooth, half as broad as the +thorax. + +_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.09 long, 0.08 +broad. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +3. _Sethamphora dodecapleura_, n. sp. + +Shell urceolate, smooth, with sharp collar stricture. Length of the two +joints = 3 : 9, breadth = 5 : 9. Cephalis flat, cap-shaped, free, with +twelve ribs, and very small pores between them. Thorax thick-walled, +inflated, with subcylindrical cavity, and twelve prominent sharp ribs, +alternating with twelve longitudinal rows of very small circular pores +(eight pores in each row). Mouth constricted, half as broad as the thorax. + +_Dimensions._--Cephalis 0.03 long, 0.05 broad; thorax 0.09 long, 0.09 +broad. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +{1251}4. _Sethamphora mongolfieri_, Haeckel. + + _Eucyrtidium mongolfieri_, Ehrenberg, 1854, Mikrogeol., Taf. xxxiv. fig. + 18; Abhandl. d. k. Akad. d. Wiss. Berlin, 1875, p. 72, Taf. x. fig. 3. + +Shell urceolate, smooth, with distinct collar stricture. Length of the two +joints = 2 : 9, breadth = 3 : 7. Cephalis campanulate, with eighteen ribs +and small pores. Thorax nearly ellipsoidal, with eighteen prominent ribs, +and eighteen longitudinal rows of regular circular pores between them +(eight pores in each row; therefore 144 pores altogether). Mouth +constricted, only one-third as broad as the thorax. + +_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.09 long, 0.07 +broad. + +_Habitat._--Fossil in Barbados. + + +5. _Sethamphora costata_, n. sp. Pl. 62, fig. 3. + +Shell urceolate, smooth, very similar to the preceding species; also with +eighteen longitudinal ribs, but differing in the larger size of the +cephalis and its pores, and in the more slender and ovate form of the +thorax. Length of the two joints = 5 : 10, breadth = 5 : 8. Pores of the +cephalis more numerous. Mouth half as broad as the thorax. + +_Dimensions._--Cephalis 0.05 long, 0.05 broad; thorax 0.1 long, 0.08 broad. + +_Habitat._--Central Pacific, Stations 265 to 274, depth 2350 to 2925 +fathoms. + + +6. _Sethamphora serrata_, n. sp. + +Shell ovate, spinulate, without external collar stricture. Length of the +two joints = 1 : 6, breadth = 2 : 4. Cephalis flat, cap-shaped, with small +circular pores. Thorax ovate, truncate, with eighteen serrate longitudinal +ribs, alternating with eighteen longitudinal rows of short and broad rather +oblong pores (twenty to thirty pores in each row). Mouth strongly +constricted, only one-fourth as broad as the thorax. + +_Dimensions._--Cephalis 0.02 long, 0.04 broad; thorax 0.12 long, 0.08 +broad. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms. + + +7. _Sethamphora ampulla_, Haeckel. + + _Eucyrtidium ampulla_, Ehrenberg, 1854, Mikrogeol., Taf. xxxvi. fig. 15; + Abhandl. d. k. Akad. d. Wiss. Berlin, 1875, p. 72, Taf. x. figs. 11, 12. + +Shell broad, urceolate, spiny, with sharp collar stricture. Length of the +two joints = 1 : 4, breadth = 1 : 5. Cephalis subspherical, with few small +pores (in figs. 12_a_ and 12_b_ of Ehrenberg, _loc. cit._, broken off, so +that the four pores of the cortinar septum appear). Thorax inflated, +bottle-shaped, with twenty prominent, sharply dentate ribs, alternating +with twenty longitudinal rows of circular pores (about eight pores in each +row). Mouth flat, constricted, one-third as broad as the thorax. + +_Dimensions._--Cephalis 0.025 long, 0.03 broad; thorax 0.1 long, 0.14 +broad. + +_Habitat._--Fossil in Barbados. + + +{1252}8. _Sethamphora aerostatica_, Haeckel. + + _Podocyrtis aerostatica_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 80, Taf. xvi. fig. 4. + +Shell broad, urceolate, smooth, with sharp collar stricture. Length of the +two joints = 2 : 6, breadth = 3 : 8. Cephalis hemispherical, large, with +few pores (broken off in fig. 4_a_ of Ehrenberg, so that the six collar +pores appear). Thorax inflated, bottle-shaped, with twenty-two to +twenty-four smooth prominent ribs, alternating with the some number of +longitudinal rows of small circular pores. Mouth very small, strongly +constricted, scarcely as broad as the cephalis, with three short teeth. + +_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.06 long, 0.08 +broad. + +_Habitat._--Fossil in Barbados. + + + +Subgenus 2. _Cryptocephalus_, Haeckel, 1881, Prodromus, p. 430. + +_Definition._--Cephalis more or less hidden in thorax, being partly +enveloped by its uppermost part. + + +9. _Sethamphora microstoma_, n. sp. (Pl. 57, fig. 5). + + _Cryptoprora microstoma_, Haeckel, Atlas, pl. lvii., fig. 5. + +Shell ovate, smooth, without external collar stricture. Length of the two +joints = 1 : 6, breadth = 2 : 4. Cephalis flat, cap-shaped, without ribs, +with small circular pores. Thorax ovate, with twenty-four prominent ribs, +alternating with deep longitudinal furrows, each of which contains a series +of about fifteen small circular pores. Mouth very small, representing a +short cylindrical tube, which is only one-eighth as broad as the thorax. + +_Dimensions._--Cephalis 0.02 long, 0.04 broad; thorax 0.12 long, 0.08 +broad. + +_Habitat._--Western Tropical Pacific, Station 220, depth 1100 fathoms. + + +10. _Sethamphora favosa_, n. sp, (Pl. 57, fig. 4). + + _Cryptocephalus favosus_, Haeckel, 1881, Prodromus, p. 430. + +Shell ovate, dimply. Length of the two joints = 1 : 5, breadth = 1 : 5. +Cephalis subspherical, small, completely hidden in the thickened top of the +thorax (but very distinct in the longitudinal section). Thorax ovate, with +twenty-five to thirty longitudinal ribs, alternating with the same number +of longitudinal furrows, each of which contains ten to twelve circular, +hexagonally framed pores. In the smooth wall of the peristome only twelve +triangular ribs are visible. Mouth constricted, one-third as broad as the +thorax. + +_Dimensions._--Cephalis 0.02 diameter; thorax 0.1 long, 0.09 broad. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + + +{1253}Genus 560. _Sethopyramis_,[177] Haeckel, 1881, Prodromus, p. 432 +(sensu emendato !) + +_Definition_.--#Sethophormida# (vel Dicyrtida multiradiata aperta) with +numerous straight or slightly curved radial ribs in the wall of the +pyramidal thorax. Network simple. Cephalis commonly without horn. + +The genus _Sethopyramis_ and the four following genera form together a +peculiar small group (Sethopyramida), characterised by the slender +pyramidal shell, in the wall of which numerous (six to nine or more) radial +ribs are enclosed. These ribs may be regarded as the terminal feet of a +_Calpophaena_ or _Halicalyptra_, which become connected by transverse bars. +_Sethopyramis_ may be derived also directly from _Patagospyris_ by loss of +the primary sagittal ring and reduction of the cephalis. + + + +Subgenus 1. _Sestropyramis_, Haeckel. + +_Definition_.--Pyramidal shell with six radial main beams (sometimes also +five or seven, as individual varieties). + + +1. _Sethopyramis scalaris_, Haeckel. + + _Cornutella scalaris_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 68, Taf. ii. fig. 1. + +Shell smooth, slenderly pyramidal, hexagonal. Cephalis large, subglobular, +hyaline, without pores (or with very small and scarce pores). Thorax with +six straight (or little curved) stout longitudinal ribs or radial beams, +which are connected by twenty to thirty complete, hexagonal, horizontal +rings. The large meshes so produced are regular, square, their length and +breadth equally and gradually increasing towards the mouth. + +_Dimensions_.--Cephalis 0.04 diameter; thorax (with twenty-four transverse +rings) 0.4 long, 0.15 broad at the mouth. + +_Habitat_.--Fossil in Barbados. + + +2. _Sethopyramis hexalactis_, n. sp. + +Shell thorny, of the same form as, and similar structure to, the preceding +species, but differing in the spiny surface and the smaller subglobular +cephalis, which bears small circular pores and an oblique conical horn +twice the length. The whole surface is covered with short conical thorns. + +_Dimensions_.--Cephalis 0.02 diameter; thorax (with twenty transverse +rings) 0.25 long, 0.1 broad. + +_Habitat_.--Central Pacific, Station 268, depth 2900 fathoms. + + + +Subgenus 2. _Cephalopyramis_, Haeckel, 1881, Prodromus, p. 432. + +_Definition._--Pyramidal shell with nine radial main beams (sometimes also +eight or ten, as individual varieties). + + +{1254}3. _Sethopyramis enneactis_, n. sp. (Pl. 56, fig. 7). + + _Cephalopyramis enneactis_, Haeckel, 1881, Prodromus et Atlas, pl. lvi. + fig. 7. + +Shell smooth, slender, pyramidal. Cephalis large, ovate, with pointed apex, +nearly hyaline, with very few and small scattered pores. Thorax very +slenderly pyramidal, with straight lateral outlines, and nine stout and +straight radial beams, which are connected by fifteen to twenty horizontal +complete rings. Meshes subregular, square, simple, without secondary +network; their length and breadth equally increasing towards the mouth. + +_Dimensions._--Cephalis 0.05 long, 0.03 broad; thorax (with twenty +transverse rings) 0.24 long, 0.1 broad at the mouth. + +_Habitat._--Central Pacific, Stations 265 to 268, depth 2700 to 2900 +fathoms. + + +4. _Sethopyramis quadrata_, n. sp. (Pl. 54, fig. 2). + +Shell smooth, slenderly pyramidal, very similar in form and structure to +the preceding species; differing from it in the rudimentary cephalis, which +is very small, hemispherical, with few small porules. The three internal +cortinar bars of the collar stricture are present; when they become lost +this species passes over into _Bathropyramis quadrata_ (Pl. 54, fig. 1). + +_Dimensions._--Cephalis 0.01 long, 0.02 broad; thorax (with ten transverse +rings) 0.15 long, 0.1 broad at the mouth. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +5. _Sethopyramis quadratella_, Haeckel. + + _Cornutella quadratella_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 68, Taf. ii. fig. 2. + + _Litharachnium quadratella_, Buetschli, 1882, Zeitschr. f. wiss. Zool., + vol, xxxvi. p. 540, Taf. xxxiii. fig. 37. + +Shell smooth, broadly pyramidal. Cephalis ovate, small, blunt, hyaline, +with very few and small pores (in the figure of Ehrenberg broken off). +Thorax broadly pyramidal, with straight lateral outlines, and nine stout +and straight radial beams, which are connected by eight to twelve +horizontal complete rings. Meshes in the upper half regular, square, in the +lower half broad, rectangular (in the tenth transverse row twice as broad +as long). + +_Dimensions._--Cephalis 0.03 long, 0.02 broad; thorax (with ten transverse +rings) 0.15 long, 0.15 broad. + +_Habitat._--Fossil in Barbados. + + +6. _Sethopyramis trapezoides_, n. sp. + +Shell smooth, broadly pyramidal. Cephalis large, ovate, hyaline, without +pores; its collar septum exhibits distinctly the four collar pores (two +larger cardinal and two smaller jugular pores). {1255}Thorax broad, +pyramidal, with slightly concave lateral outlines and nine (sometimes eight +or ten) curved ribs, which are connected by eighteen to twenty-four +complete transverse rings. The large meshes, so produced, have the form of +a parallel trapezoid, and are in the eighth transverse row three times as +broad as long. (Differs from _Bathropyramis trapezoides_, Pl. 54, fig. 3, +mainly by the possession of a well developed cephalis). + +_Dimensions._--Cephalis 0.04 long, 0.03 broad; thorax (with eighteen rings) +0.32 long, 0.24 broad. + +_Habitat._--South Pacific, Station 285, depth 2375 fathoms. + + +7. _Sethopyramis spinosa_, n. sp. + +Shell thorny, slender, pyramidal. Cephalis small, subspherical, with few +small pores and a straight, vertical, conical horn twice the length. Thorax +with nine straight ribs, which are connected by sixteen to twenty complete +transverse nine-angled rings. The large meshes so produced are subregular, +square. From each nodal point a short conical spine arises. (Differs from +the similar _Bathropyramis spinosa_, Pl. 54, fig. 4, by the development of +the cephalis and the simple pointed, unforked spines.) + +_Dimensions._--Cephalis 0.03 diameter; thorax (with sixteen rings) 0.2 +long, 0.12 broad. + +_Habitat._--Central Pacific, Station 263, depth 2650 fathoms. + + +8. _Sethopyramis hexagonalis_, n. sp. + +Shell papillate, slender, pyramidal. Cephalis small, hemispherical, with a +straight conical horn twice the length, and small circular pores. Thorax +conical, with slightly convex outlines and nine stout, somewhat curved ribs +in zig-zag form, which are connected by ten to twelve interrupted +transverse bars. From each nodal point a small conical papilla arises. The +large meshes so produced are regular, hexagonal, gradually increasing in +size towards the mouth. + +_Dimensions._--Cephalis 0.03 diameter; thorax (with twelve transverse rows +of meshes) 0.18 long, 0.12 broad. + +_Habitat._--South Atlantic, Station 335, depth 1425 fathoms. + + +9. _Sethopyramis cyclomma_, n. sp. + +Shell thorny, slender, pyramidal. Cephalis large, subspherical, with +numerous very small circular pores, and a small conical horn of the same +length. Thorax similar in form and structure to that of the preceding +species; but each hexagonal mesh is provided with a very thin circular +hyaline ring (like a diaphragm), so that the openings are not hexagonal, +but circular. From each nodal point a short pointed conical or slightly +forked spine arises. + +_Dimensions._--Cephalis 0.02 diameter; thorax (with ten transverse rows of +meshes) 0.18 long, 0.14 broad. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms. + + + +{1256}Subgenus 3. _Actinopyramis_, Haeckel. + +_Definition._--Pyramidal shell with twelve or more radial beams (commonly +twelve to twenty-four, sometimes forty or more). + + +10. _Sethopyramis dodecalactis_, n. sp. + +Shell smooth, slender, pyramidal. Cephalis small, spherical, hyaline, with +a short conical horn. Thorax with twelve radial ribs in the upper half, +between which twelve others are interpolated in the lower half. These are +connected by twenty to twenty-four complete transverse rings. The meshes so +produced are subregular, rectangular. + +_Dimensions._--Cephalis 0.03 diameter; thorax 0.6 long, 0.2 broad. + +_Habitat._--Indian Ocean, Madagascar (Rabbe), surface. + + +11. _Sethopyramis bicornis_, n. sp. + +Shell spiny, slender, pyramidal. Cephalis small, spherical, hyaline, with +two divergent conical horns, the major (occipital) three times and the +minor (frontal) twice as long. Thorax slender, pyramidal, campanulate, +thorny, with twenty to thirty radial beams, which are little curved, convex +in the upper, concave in the lower half, and connected by numerous +interrupted transverse bars. Meshes in the upper third rounded, in the +lower two-thirds quadrangular, of very different sizes. Surface covered +with spinules. + +_Dimensions._--Cephalis 0.02 diameter; thorns 0.9 long, 0.4 broad. + +_Habitat._--North Pacific, Station 241, depth 2300 fathoms. + + +12. _Sethopyramis maxima_, n. sp. + +Shell smooth, slender, pyramidal. Cephalis small, spherical, with few small +pores, and a stout, vertical, conical horn twice the length. Thorax very +prolonged, conical, with straight lateral outlines and numerous (twenty to +fifty) radial beams (in the upper third twelve, in the middle third +twenty-four, in the lower third forty to fifty, by interpolation); they are +connected by very numerous interrupted transverse bars. Meshes subregular, +quadrangular. Surface smooth. + +_Dimensions._--Cephalis 0.02 diameter; thorax 1.05 long, 0.45 broad. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +Genus 561. _Plectopyramis_,[178] Haeckel, 1881, Prodromus, p. 432. + +_Definition._--#Sethophormida# (vel Dicyrtida multiradiata aperta) with +numerous straight or slightly curved radial ribs in the wall of the +pyramidal thorax. Network double, the large primary meshes being +fenestrated by fine secondary network. Cephalis commonly without horn. + +{1257}The genus _Plectopyramis_ differs from the preceding _Sethopyramis_, +its ancestral form, only in the peculiar double fenestration of the shell, +the large primary meshes of which are separated by strong bars, and filled +up by a very delicate arachnoidal network, composed of small pores and very +thin threads between them. This double lattice-work often exhibits a very +remarkable regularity. As in the preceding genus, the number of radial ribs +is commonly six or nine, rarely twelve to twenty or more. + + + +Subgenus 1. _Hexapleuris_, Haeckel. + +_Definition._--Pyramidal shell with six radial main beams (sometimes five +or seven in individual varieties). + + +1. _Plectopyramis magnifica_, Haeckel. + + _Polycystina magnifica_, Bury, 1862, Polycystins of Barbados, pl. xi. + fig. + +Shell smooth, slender, pyramidal. Cephalis large, ovate, pointed, separated +from the thorax by a very deep collar stricture, with few irregular pores. +Thorax with six strong and straight radial beams, which are connected by +about twenty horizontal, hexagonal rings. The large meshes so produced are +regular, square, and filled up by an extremely delicate secondary +arachnoidal network, composed of regular square pores (as in Pl. 54, figs. +7, 8). + +_Dimensions._--Cephalis 0.06 long, 0.04 broad; thorax (with twenty +transverse rings) 0.4 long, 0.12 broad. + +_Habitat._--Fossil in Barbados. + + +2. _Plectopyramis hexapleura_, n. sp. + +Shell thorny, slender, pyramidal. Cephalis large, ovate, blunt, with deep +collar stricture. Thorax with six strong and straight radial beams, which +are connected by numerous (twenty to thirty) interrupted transverse bars. +The large meshes so produced are irregular, quadrangular, and filled up by +irregular, delicate, secondary network, with small polygonal pores. + +_Dimensions._--Cephalis 0.05 long, 0.03 broad; thorax 0.3 long, 0.1 broad. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + + +Subgenus 2. _Enneapleuris_, Haeckel. + +_Definition._--Pyramidal shell with nine radial main beams (sometimes eight +or ten in individual varieties). + + +{1258}3. _Plectopyramis dodecomma_, n. sp. (Pl. 54, fig. 6). + +Shell smooth, slenderly pyramidal, with straight outlines. Cephalis +conical, obtuse, with thirty-six small square pores (in nine divergent +longitudinal rows, each of four pores). Collar septum (between cephalis and +thorax) with four distinct collar pores. Thorax pyramidal, with nine very +stout and straight angular radial beams, which are connected by ten to +fifteen broad horizontal nine-angled rings. Each of the large regular, +square meshes so produced contains a very delicate fenestration, with +twelve regular, square pores, separated by two transverse and three +longitudinal crossed threads. A very regular and remarkable structure. + +_Dimensions._--Cephalis 0.03 long, 0.02 broad; thorax (with ten rings) 0.2 +long, 0.15 broad. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +4. _Plectopyramis quadratomma_, n. sp. + +Shell smooth, slenderly pyramidal. Cephalis large, ovate, hyaline, with few +very small basal pores and deep collar stricture. Thorax pyramidal, with +straight outline, and nine very stout and straight radial beams, which are +connected by fifteen to twenty horizontal nine-angled rings. Each of the +large regular, square meshes so produced is filled up by a very delicate +arachnoidal network, with very numerous and small square pores (as in the +similar _Cinclopyramis infundibulum_, Pl. 54, fig. 7, which differs in the +loss of the cephalis). + +_Dimensions._--Cephalis 0.05 long, 0.03 broad; thorax (with fifteen rings) +0.32 long, 0.2 broad. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +5. _Plectopyramis trapezomma_, n. sp. (Pl. 54, fig. 8). + +Shell smooth, broadly pyramidal, with concave lateral outlines. Cephalis +hemispherical, small, with numerous small, circular pores. Thorax +pyramidal, with nine stout, concavely curved radial beams, which are +connected by twelve to sixteen horizontal nine-angled rings. The large +meshes so produced are in the upper half square, in the lower half parallel +trapezoid (in the fifteenth ring three times as broad as long), and filled +up by a secondary arachnoidal network, with very numerous and small square +pores. + +_Dimensions._--Cephalis 0.015 long, 0.025 broad; thorax (with fifteen +rings) 0.22 long, 0.2 broad. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +6. _Plectopyramis polygonomma_, n. sp. + +Shell smooth, pyramidal, very similar to the preceding species; differing +from it in the irregular shape of the delicate polygonal (not tetragonal) +secondary network, filling up the large rectangular meshes. The cephalis is +larger, hyaline, pear-shaped, pointed, without pores, with a deep collar +stricture. The nine radial beams of the thorax are less concave. + +_Dimensions._--Cephalis 0.04 long, 0.03 broad; thorax (with fifteen rings) +0.3 long, 0.22 broad. + +_Habitat._--South Pacific, Station 295, depth 1500 fathoms. + + +{1259}7. _Plectopyramis heteromma_, n. sp. + +Shell smooth, slenderly pyramidal, with concave outlines. Cephalis very +small, subspherical, with a small oblique, conical horn, and very small, +scarce circular pores. Thorax with nine stout concavely curved radial +beams, which are connected by numerous (thirty to fifty or more) +interrupted transverse bars. The large irregular meshes so produced are +filled up by irregular, polygonal, delicate lattice-work. + +_Dimensions._--Cephalis 0.02 long, 0.02 broad; thorax 0.6 long, 0.3 broad. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +8. _Plectopyramis serrata_, n. sp. + +Shell thorny, slenderly pyramidal, with straight outlines. Cephalis very +small, spherical, with a long oblique, conical horn, and very small +circular pores. Thorax with nine stout, straight, regularly serrate ribs or +radial beams, which are connected by numerous (twenty to thirty or more) +interrupted transverse bars. The latter, being crossed by intercalated and +interrupted irregular radial beams, produce a subregular secondary network +of rectangular meshes of different sizes. + +_Dimensions._--Cephalis 0.02 long, 0.02 broad; thorax, 0.3 long, 0.2 broad. + +_Habitat._--South Pacific, Station 298, depth 2225 fathoms. + + +9. _Plectopyramis fenestrata_, Haeckel. + + _Pyramis fenestrata_, Bury, 1862, Polycystins of Barbados, pl. xxi. fig. + 8. + +Shell thorny, broadly pyramidal, with straight outlines. Cephalis very +small, spherical, hyaline. Thorax with nine stout, spinulate, straight ribs +or radial beams, which are connected by ten to fifteen transverse bars, +which in the upper half are complete rings, in the lower half interrupted, +and crossed by irregularly intercalated radial beams. Meshes therefore +irregular, quadrangular. All the bars are thorny. + +_Dimensions._--Cephalis 0.01 diameter; thorax 0.2 long, 0.16 broad. + +_Habitat._--Tropical Atlantic. + + +10. _Plectopyramis furcata_, n. sp. + +Shell spiny, slenderly pyramidal, with straight outlines. Cephalis small, +spherical, with few small pores. Thorax with nine stout and straight +spinulate ribs, which are connected by a variable number of irregular +interrupted transverse bars; the large quadrangular meshes so produced are +filled up by irregular delicate network. The entire surface of the thorax +is covered with short forked spines. + +_Dimensions._--Cephalis 0.02 diameter; thorax 0.3 long, 0.2 broad. + +_Habitat._--Indian Ocean (Zanzibar), Pullen, depth 2200 fathoms. + + + +{1260}Subgenus 3. _Polypleuris_, Haeckel. + +_Definition._--Pyramidal shell with numerous (twelve or more) radial main +beams (commonly twelve to eighteen, sometimes twenty to thirty or more). + + +11. _Plectopyramis polypleura_, n. sp. (Pl. 56, fig. 8). + +Shell smooth, slenderly conical, with straight outlines. Cephalis small, +subspherical, with very small dot-like pores, and an oblique conical horn +twice the length. Thorax with numerous (twenty to thirty) divergent +longitudinal ribs; usually twelve of these radial beams appear as stronger, +primary main ribs, and twelve to eighteen other as secondary, feebler, +interpolated ribs. They are crossed by numerous (twenty to forty or more) +horizontal rings. The large meshes so produced are quadrangular, and partly +filled up by a very delicate secondary network, with small square pores. + +_Dimensions._--Cephalis 0.03 diameter; thorax 0.36 long, 0.24 broad. + +_Habitat._--Central Pacific, Station 267, depth 2700 fathoms. + + +12. _Plectopyramis lagena_, n. sp. + +Shell smooth, wine-bottle shaped, or slenderly conical-campanulate, with +bent outlines, which are concave in the upper, convex in the lower half. +Cephalis very small, spherical, hyaline, without pores. Thorax with +twenty-four radial ribs, twelve stronger primary, alternating with twelve +feebler secondary. They are crossed by interrupted transverse bars. The +irregular quadrangular meshes so produced are filled up by a delicate, +irregular, secondary network. + +_Dimensions._--Cephalis 0.02 diameter; thorax 0.5 long, 0.3 broad. + +_Habitat._--South Atlantic, Station 335, depth 1425 fathoms. + + + +Genus 562. _Spongopyramis_,[179] n. sp. + +_Definition._--#Sethophormida# (vel Dicyrtida multiradiata aperta) with +numerous straight or slightly curved radial ribs in the wall of the +pyramidal thorax. Network spongy. Cephalis commonly without horn. + +The genus _Spongopyramis_ has arisen from _Sethopyramis_ by development of +an irregular spongy framework around the lattice-shell, and is one of the +small number of #Cyrtoidea# in which the shell-wall exhibits a spongy +structure. In both observed species the cephalis is small, but evident. + + +{1261}1. _Spongopyramis spongiosa_, n. sp. (Pl. 56, fig. 10). + + _Plectopyramis spongiosa_, Haeckel, 1881, Prodromus et Atlas, _loc. cit._ + +Shell partly or entirely enveloped by spongy framework, slender, pyramidal, +with rather straight outlines. Cephalis very small, ovate, hyaline. Thorax +with nine very stout and nearly straight ribs, which are connected by +fifteen to twenty or more irregular, interrupted transverse bars. The +irregular quadrangular meshes so produced are filled up by an irregular +secondary network, with meshes of very different size and form. The dense +spongy envelope, which in the specimen figured covered only half the shell, +was complete in another older specimen. + +_Dimensions._--Cephalis 0.015 long, 0.01 broad; thorax 0.4 long, 0.25 +broad. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +2. _Spongopyramis spongoplecta_, n. sp. + +Shell entirely enveloped by spongy framework, pyramidal, with straight +outlines. Cephalis ovate (twice as large as in the preceding species), with +small circular pores. Thorax with twelve stout and straight ribs, which are +connected by twenty to twenty-five annular, transverse bars. The subregular +square meshes so produced are filled up by irregular, spongy network, which +envelops the whole shell more loosely than in _Spongopyramis spongiosa_. + +_Dimensions._--Cephalis 0.03 long, 0.02 broad; thorax 0.5 long, 0.2 broad. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + + +Genus 563. _Acanthocorys_,[180] Haeckel, 1881, Prodromus, p. 432. + +_Definition._--#Sethophormida# (vel Dicyrtida multiradiata aperta) with +numerous radial ribs in the wall of the pyramidal thorax, prolonged into +divergent terminal feet. Network simple. Cephalis commonly with several +horns. + +The genus _Acanthocorys_ and the following nearly allied _Arachnocorys_ +possess a near relation to the three preceding pyramidal genera, but differ +from them in the terminal prolongation of the radial ribs, which are +commonly spiny and form a corona of free feet around the mouth of the +thorax. The cephalis is usually much larger than in the three preceding +genera, and bears a variable number of radial horns. Therefore these two +genera are probably older and nearer to the common ancestral form of the +Sethophormida than the preceding genera. It may be derived directly from +_Dictyophimus_ by interpolation of three secondary (interradial) ribs +between the three primary (perradial) ribs. + + + +{1262}Subgenus 1. _Acanthocorallium_, Haeckel. + +_Definition._--Thorax with six divergent ribs or radial beams (three +primary or perradial alternating with three secondary or interradial). + + +1. _Acanthocorys hexapodia_, n. sp. + +Cephalis large, ovate, with subregular hexagonal pores, and six strong, +conical, simple, divergent horns of the same length. Thorax flat, conical, +smooth, with six large triangular basal holes, separated by six strong, +prismatic, smooth beams, which are connected only near the distal end by a +hexagonal ring of delicate, irregular network. Collar septum with three +meshes, separated by the three centripetal prolongations of the three +primary ribs. + +_Dimensions._--Cephalis 0.05 long, 0.04 broad; thorax 0.12 long, 0.24 +broad. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + +2. _Acanthocorys pristipodia_, n. sp. + +Cephalis large, hemispherical, with irregular, polygonal pores, and +numerous (ten to twenty) bristle-shaped, radiating horns, which are conical +at the base, and twice as long. Thorax flatly campanulate, thorny, with six +strong, serrate or spinulate, divergent, radial ribs, prolonged into six +free conical feet of the same length. Meshes of the thorax irregular, +polygonal, a corona of six larger ones at the base. Collar septum with four +meshes, shaped as in Pl. 56, fig. 6. + +_Dimensions._--Cephalis 0.04 long, 0.06 broad; thorax 0.08 long, 0.18 +broad. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +3. _Acanthocorys macropodia_, n. sp. + +Cephalis small, subspherical, with irregular, roundish pores and numerous +small, bristle-shaped horns. Length of the two joints = 1 : 2, breadth = +1 : 6. Thorax sexangular, pyramidal, with six very long and straight, +widely divergent feet, which are prismatic and spiny, and three to five +times as long as the breadth of the shell. Only the upper third of the six +ribs is connected by irregular, roundish network, with six large triangular +holes at the base. Collar septum with four meshes which have the same +relation to the six ribs as in _Sethophormis hexalactis_ (Pl. 56, fig. 6). + +_Dimensions._--Cephalis 0.025 diameter, thorax 0.05 long, 0.15 broad. + +_Habitat._--Central Pacific, Station 271, surface. + + +4. _Acanthocorys buetschlii_, Haeckel. + + ? _Clathrocanium ehrenbergii_, Buetschli, 1882, Zeitschr. f. wiss. Zool., + vol. xxxvi. pp. 514, 539, Taf. xxxii. fig. 18, _a_, _b_. + +Cephalis large, subspherical, with numerous small, circular pores and three +to six divergent, slender, apical horns. Thorax flatly conical, smooth, not +much larger than the cephalis, with six {1263}large, triangular or ovate +basal holes between the six ribs. Three of these ribs are primary or +perradial, and arise immediately from the collar septum, alternating with +three secondary or interradial ribs, which arise more outside. The specimen +observed by me exhibited six apical horns, and was more complete than that +figured by Buetschli, the six ribs being prolonged over the connecting +lattice-girdle into six short, divergent feet. + +_Dimensions._--Cephalis 0.06 long, 0.06 broad; thorax 0.08 long, 0.1 broad. + +_Habitat._--Fossil in Barbados. + + + +Subgenus 2. _Acanthocoronium_, Haeckel. + +_Definition._--Thorax with nine divergent ribs or radial beams, three of +which are primary or perradial, the other six secondary or interradial. + + +5. _Acanthocorys umbellifera_, Haeckel. + + _Arachnocorys umbellifera_, Haeckel, 1862, Monogr. d. Radiol., p. 305, + Taf. vi. fig. 12. + +Cephalis large, ovate, with subregular, circular pores and numerous +divergent, simple spines of different lengths. Thorax flatly conical, with +nine strong, divergent ribs, which in the distal half are free, in the +proximal half connected by numerous transverse beams, forming irregular +polygonal meshes. Dorsal face of the thorax armed with scattered ascending +spines. + +_Dimensions._--Cephalis 0.05 long, 0.035 broad; thorax 0.05 long, 0.12 +broad. + +_Habitat._--Mediterranean (Messina); Atlantic, Station 354, surface. + + +6. _Acanthocorys triloba_, n. sp. + +Cephalis large, campanulate, trilobed, with irregular, roundish pores, +numerous spines, and a large pyramidal horn on the top, which is connected +by three constricted arches with the base of the horizontal collar beams. +From the latter arise as centrifugal prolongations three stout, curved, +primary ribs of the flatly vaulted thorax, and each of these gives off at +the base two opposite, lateral, secondary ribs. These nine ribs are spiny, +and connected by irregular, arachnoidal network. + +_Dimensions._--Cephalis 0.05 long, 0.07 broad; thorax 0.08 long, 0.18 +broad. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +7. _Acanthocorys enneapodia_, n. sp. + +Cephalis large, ovate, with irregular roundish pores, and numerous +divergent, ascending spines. Thorax smooth, conical, little larger, with +the same network, and nine larger, triangular holes at the base; with nine +straight, equally-disposed ribs, which are prolonged into slender feet +twice the length. With these latter alternate nine shorter radial spines, +arising from the truncate peristome. + +_Dimensions._--Cephalis 0.05 long, 0.04 broad; thorax 0.05 long, 0.09 +broad. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms. + + +{1264}8. _Acanthocorys macroceras_, n. sp. (Pl. 97, fig. 12). + +Cephalis large, hemispherical, spiny, with regular, circular pores, and a +very large, cylindrical, vertical horn five times as long as the whole +shell. Thorax spiny, campanulate, with irregular, roundish pores and nine +strong, curved ribs, prolonged into nine slender, divergent feet twice the +length, which are curved, convex in the proximal half and concave in the +distal half. + +_Dimensions._--Cephalis 0.05 long, 0.08 broad; thorax 0.12 long, 0.2 broad. + +_Habitat._--South Pacific, Station 298, depth 2225 fathoms. + + +9. _Acanthocorys furcata_, n. sp. + +Cephalis large, subspherical, spiny, with irregular, roundish pores. Thorax +flatly conical, thorny, with irregular, polygonal pores, decreasing in size +toward the mouth, and with nine straight divergent ribs, which at the +peristome are forked and prolonged into eighteen slender, very long, +bristle-shaped feet. + +_Dimensions._--Cephalis 0.045 diameter, thorax 0.07 long, 0.13 broad. + +_Habitat._--South Atlantic, Station 323, depth 1900 fathoms. + + + +Subgenus 3. _Acanthocorythium_, Haeckel. + +_Definition._--Thorax with a variable number (ten to twenty or more) radial +ribs, prolonged into free terminal feet. + + +10. _Acanthocorys dodecaster_, n. sp. + +Cephalis small, subspherical, with small circular pores and a large conical +horn of twice the length, and some accessory spines. Thorax thorny, flatly +campanulate, with twelve stout curved ribs, which at the peristome are +prolonged into twelve slender, curved feet of twice the length; four of +them are centrifugal prolongations of the four cortinar beams separating +the four large meshes of the collar septum; eight other ribs are secondary, +interpolated in pairs between the former. At the base of the thorax are +twelve large triangular holes between the ribs; the other network is +irregular, with polygonal meshes. + +_Dimensions._--Cephalis 0.03 diameter, thorax 0.05 long, 0.12 broad. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +11. _Acanthocorys polypodia_, n. sp. + +Cephalis small, hemispherical, with small, roundish pores and divergent +radial spines. Thorax flatly conical, spiny, with twenty to twenty-four +divergent, straight ribs, which in the proximal {1265}third are separated +by the same number of large, triangular meshes, in the middle third +connected by irregular network, in the distal third free. + +_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.06 long, 0.15 +broad. + +_Habitat._--Central Pacific, Station 273, depth 2350 fathoms. + + + +Genus 564. _Arachnocorys_,[181] Haeckel, 1860, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 837. + +_Definition._--#Sethophormida# (vel Dicyrtida multiradiata aperta) with +numerous radial ribs in the wall of the pyramidal thorax, prolonged into +divergent terminal feet. Network double, with an arachnoidal outer mantle +around the inner lattice-shell. Cephalis commonly with numerous horns. + +The genus _Arachnocorys_ has been derived from the preceding +_Acanthocorys_, by development of numerous external siliceous threads which +connect the radial horns of the cephalis with the secondary spines arising +from the thoracic ribs. In this way there becomes formed an outer +arachnoidal framework, enveloping loosely, like a delicate mantle, the +inner primary lattice-shell. + + + +Subgenus 1. _Arachnocorallium_, Haeckel. + +_Definition._--Thorax with six divergent ribs or radial beams (three +primary or perradial, alternating with three secondary or interradial). + + +1. _Arachnocorys hexaptera_, n. sp. + + _Arachnocorys circumtexta_ (juv.?), R. Hertwig, 1879, Organism. d. + Radiol., p. 79, Taf. viii. fig. 2_a_. + +Cephalis large, subspherical, with irregular, polygonal pores, and numerous +bristle-shaped spines twice the length; on the centre of the top a single +larger vertical horn. Thorax flatly conical, with six strong and straight +widely divergent ribs, which in the proximal half are separated by six +large holes, in the distal half connected by a broad ring of irregular +network. From each rib arises a perpendicular branch, and these branches +are connected together, and with the spines of the cephalis, by arachnoidal +network. + +_Dimensions._--Cephalis 0.04 diameter, thorax 0.08 long, 0.24 broad. + +_Habitat._--Central Pacific, Station 266; Mediterranean, surface. + + +2. _Arachnocorys discoides_, n. sp. + +Cephalis small, pyramidal, with irregular, roundish pores and numerous thin +spines, on the top a single larger vertical horn. Thorax very flat, nearly +discoidal, with six strong and straight ribs, {1266}which by communication +of few larger and numerous smaller branches form an irregular network with +polygonal meshes. From each of the six ribs arise two or three larger, +perpendicular branches of half the length, and from the network numerous +smaller spines. All these dorsal spines of the shell are connected by a +dense arachnoidal wicker-work. + +_Dimensions._--Cephalis 0.02 diameter, thorax 0.04 long, 0.3 broad. + +_Habitat._--Central Pacific, Station 271, surface. + + + +Subgenus 2. _Arachnocoronium_, Haeckel. + +_Definition._--Thorax with nine divergent ribs or radial beams, three of +which are primary or perradial, the other six secondary or interradial. +(Sometimes eight or ten occur instead of the nine normal ribs.) + + +3. _Arachnocorys circumtexta_, Haeckel. + + _Arachnocorys circumtexta_, Haeckel, 1862, Monogr. d. Radiol., p. 304, + Taf. vi. figs. 9-11. + + _Arachnocorys circumtexta_, R. Hertwig, 1879, Organism. d. Radiol., p. + 78, Taf. viii. fig. 2. + +Cephalis large, subspherical, with numerous roundish pores, and eight to +ten slender, conical horns twice the length. Thorax flatly conical, with +nine strong, straight, widely divergent, conical feet, each of which bears +in the middle of its outer side a perpendicular ascending branch of half +the length. These branches and the horns of the cephalis are connected by +very thin, parallel, arachnoidal threads. Network of the thorax irregular, +with nine larger triangular holes at the base. Collar septum with numerous, +irregular, roundish pores. + +_Dimensions._--Cephalis 0.04 to 0.05 diameter, thorax 0.08 to 0.12 long, +0.15 to 0.25 broad. + +_Habitat._--Mediterranean (Messina); Atlantic, Stations 347 to 354, +surface. + + +4. _Arachnocorys enneaptera_, n. sp. + +Cephalis large, campanulate, with irregular, polygonal pores, two larger +stout pyramidal and numerous slender, bristle-shaped horns. Thorax of the +same structure as in the preceding species, only the nine basal holes are +of twice the size; the lower network denser (as in _Clathrocanium diadema_, +Pl. 64, fig. 2). Collar septum with numerous, irregular, roundish pores. + +_Dimensions._--Cephalis 0.05 diameter, thorax 0.12 long, 0.22 broad. + +_Habitat._--Tropical Atlantic, Station 338, surface. + + +5. _Arachnocorys araneosa_, n. sp. (Pl. 56, fig. 11). + +Cephalis large, subspherical, with circular, subregular, hexagonally framed +pores, and twenty to thirty slender, cylindrical, straight radial spines. +Thorax flatly conical, nearly of the same shape as in the two preceding +species, but with nine longer ribs, and more irregular, broader network +between them. From the middle of each rib arises, nearly horizontally, a +strong branch, which is directed {1267}outwards. These branches are +connected with the spines of the cephalis as well as with the distal half +of the ribs, by dense and delicate arachnoidal network, composed of +parallel, very thin, siliceous threads (in fig. 11 only partially +represented). Collar septum with numerous irregular, roundish pores. + +_Dimensions._--Cephalis 0.04 diameter, thorax 0.1 long, 0.2 broad. + +_Habitat._--Central Pacific, Station 270 to 274, surface. + + +6. _Arachnocorys arachnodiscus_, n. sp. + +Cephalis small, campanulate, conical, with a single very large conical +central horn, and numerous smaller accessory spines. Thorax in form and +structure similar to that of the three preceding species, but much flatter, +being nearly discoidal. The meshes of the network are smaller and more +numerous, irregularly polygonal, and the nine basal holes little larger. +Collar septum with four large meshes (as in Pl. 60, fig. 6). + +_Dimensions._--Cephalis 0.25 long, 0.3 broad; thorax 0.04 long, 0.24 broad. + +_Habitat._--North Pacific, Station 248, surface. + + +7. _Arachnocorys trifida_, n. sp. + +Cephalis large, campanulate, with irregular, roundish pores and numerous +ramified spines; in the centre of the top a larger pyramidal oblique horn +of twice the length. Thorax cap-shaped, flatly vaulted, with nine strong +convex ribs, prolonged into slender free feet. Three of these nine ribs are +the centrifugal prolongations of the three cortinar bars (united in the +centre of the collar stricture, separating its three large cortinar +meshes); the other six are diverging lateral branches of the former, +arising in pairs at both sides of its base. All nine ribs are connected by +delicate arachnoidal network with irregular polygonal meshes. From its +surface arise thin bristles, and from the base of each main rib a stout, +perpendicular branch. All these dorsal spines are connected by irregular, +arachnoidal wicker-work, covering thorax and cephalis. (A remarkable +primitive species?) + +_Dimensions._--Cephalis 0.05 long, 0.06 broad; thorax 0.07 long, 0.18 +broad. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +Subgenus 3. _Arachnocorythium_, Haeckel. + +_Definition._--Thorax with a variable number of radial ribs (twelve to +twenty or more), prolonged into free terminal feet. + + +8. _Arachnocorys polyptera_, n. sp. + +Cephalis large, subspherical, with irregular, roundish pores and numerous +radial spines. Thorax flatly conical, with numerous radial ribs (twenty to +thirty), which are in the distal half free, in the proximal half connected +by delicate arachnoidal wicker-work, with polygonal, irregular meshes. From +its dorsal face arise numerous radial spines, which are connected together, +and with the cephalic spines, by very thin and numerous threads, parallel +between every two spines. Similar to {1268}_Arachnocorys araneosa_ (Pl. 56, +fig. 11), but differing in the structure of the cephalis, and in the +greater number of the ribs and spines. + +_Dimensions._--Cephalis 0.04 diameter, thorax 0.12 long, 0.24 broad. + +_Habitat._--South Pacific, Station 300, depth 1375 fathoms. + + + +Genus 565. _Anthocyrtoma_,[182] n. gen. + +_Definition._--#Sethophormida# (vel Dicyrtida multiradiata aperta) without +thoracic ribs, with six terminal feet around the mouth. Cephalis free, with +an apical horn. + +The genus _Anthocyrtoma_ and the four following genera form together the +peculiar group of Carpocanida, comprising all those Sethophormida in which +the original thoracic ribs are lost, and only the terminal feet remain. +_Anthocyrtoma_ is the simplest form of this group, possessing only six +terminal feet, three primary perradial, and three alternating, secondary, +interradial. It may be directly derived either from _Lychnocanium_, by +interpolation of three interradial feet, or from _Hexaspyris_ by loss of +the sagittal ring. + + +1. _Anthocyrtoma serrulata_, Haeckel. + + _Anthocyrtis serrulata_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 66, Taf. vi. fig. 7. + +Shell pear-shaped, rough, with obliterated collar stricture. Length of the +two joints = 1 : 4, breadth = 1 : 3. Cephalis ovate, with very small pores, +and a stout conical horn of the same length. Abdomen inflated, truncate, +with larger, regular, circular pores, twice as broad as the constricted +mouth. Six feet vertical, parallel, serrate, all of the same size, about as +long as the cephalis. + +_Dimensions._--Cephalis 0.06 long, 0.05 broad; thorax 0.2 long, 0.17 broad. + +_Habitat._--Fossil in Barbados. + + +2. _Anthocyrtoma alterna_, n. sp. + +Shell pear-shaped, smooth, with distinct collar stricture. Length of the +two joints = 1 : 5, breadth = 1 : 6. Cephalis hemispherical, with a slender +conical horn of twice the length. Abdomen inflated, subglobular, with +regular, circular, hexagonally framed pores, three times as broad as the +narrow, constricted mouth. Six feet conical, smooth, somewhat divergent, +alternating, of different sizes; the three larger (perradial) half as long +as the shell, and twice as long as the three smaller (interradial). +(Similar to _Anthocyrtis ventricosa_.) + +_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.15 long, 0.18 +broad. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + + +{1269}Genus 566. _Anthocyrtis_,[183] Ehrenberg, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, 1847, p. 54. + +_Definition._--#Sethophormida# (vel Dicyrtida multiradiata aperta) without +thoracic ribs, with nine terminal feet around the mouth. Cephalis free, +with an apical horn. + +The genus _Anthocyrtis_ (in the original definition of Ehrenberg) contained +all Dicyrtida without thoracic ribs, with terminal feet. We here restrict +the definition to those Sethophormida in which the number of free terminal +feet is constantly nine (three primary perradial and three alternate pairs +of secondary interradial feet). _Anthocyrtis_ may be derived either +directly from _Patagospyris_ by loss of the sagittal ring, or from +_Lychnocanium_ by interpolation of three secondary feet. + + + +Subgenus 1. _Anthocyrtella_, Haeckel. + +_Definition._--Feet of the peristome-corona divergent, their basal distance +less than their terminal distance. + + +1. _Anthocyrtis mespilus_, Ehrenberg. + + _Anthocyrtis mespilus_, Ehrenberg, 1854, Taf. xxxvi. fig. 13; Abhandl. d. + k. Akad. d. Wiss. Berlin, 1875, p. 66, Taf. vi. fig. 4 (not 5). + +Shell smooth, with distinct collar stricture. Length of the two joints = +1 : 5, breadth = 2 : 6. Cephalis hemispherical, with a stout pyramidal horn +of twice the length. Thorax nearly hemispherical, with regular, circular, +quincuncial pores. Mouth scarcely constricted, with nine divergent, +triangular, lamellar feet, about as long as the thorax. + +_Dimensions._--Cephalis 0.012 long, 0.02 broad; thorax 0.05 long, 0.06 +broad. + +_Habitat._--Fossil in Barbados. + + +2. _Anthocyrtis furcata_, Ehrenberg. + + _Anthocyrtis furcata_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 64, Taf. vi. fig. 2. + +Shell smooth, with deep collar stricture. Length of the two joints = 1 : 5, +breadth = 2 : 6. Cephalis hemispherical, with a short pyramidal horn of +half the length. Thorax hemispherical, with large, irregular, roundish +pores. Mouth scarcely constricted, with nine divergent, curved, slender +feet, which are about as long as the shell, and forked at the distal end. + +_Dimensions._--Cephalis 0.01 long, 0.02 broad; thorax 0.05 long, 0.06 +broad. + +_Habitat._--Fossil in Barbados. + + +{1270}3. _Anthocyrtis butomus_, n. sp. + +Shell thorny, with obliterated collar stricture. Length of the two joints = +2 : 6, breadth = 2 : 7. Cephalis ovate, with very small and scarce pores, +and a conical horn of the same length. Thorax inflated, pear-shaped, with +regular, circular, quincuncial pores. Mouth about half as broad, +constricted, with nine divergent, broad, nearly square, lamellar feet, half +as long as the thorax (similar to _Anthocyrtis serrulata_, Ehrenberg, _loc. +cit._, Taf. vi. fig. 7). + +_Dimensions._--Cephalis 0.05 long, 0.04 broad; thorax 0.12 long, 0.14 +broad. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +4. _Anthocyrtis ventricosa_, Ehrenberg. + + _Anthocyrtis ventricosa_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 66, Taf. viii. fig. 1. + +Shell thorny, with obliterated collar stricture. Length of the two joints = +1 : 7, breadth = 2 : 7. Cephalis hemispherical, hyaline, without pores, +with a slender, conical horn, of about the same length. Thorax inflated, +pear-shaped or subspherical, with regular, circular, quincuncial pores. +Mouth only one-third as broad, much constricted, with nine divergent, +slender, conical feet, about one-fifth as long as the diameter of the shell +(partly broken off in Ehrenberg's figure). + +_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.14 long, 0.14 +broad. + +_Habitat._--Tropical Atlantic, Station 338, depth 1990 fathoms; also fossil +in Barbados. + + + +Subgenus 2. _Anthocyrtissa_, Haeckel. + +_Definition._--Feet of the peristome-corona parallel, vertical; their basal +and terminal distances equal. + + +5. _Anthocyrtis ophirensis_, Ehrenberg. + + _Anthocyrtis ophirensis_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 285, Taf. ix. fig. 13. + +Shell smooth, with slight collar stricture. Length of the two joints = +2 : 4, breadth = 1 : 5. Cephalis ovate, with irregular, roundish pores, and +a pyramidal, excentric, vertical horn of the same length. Thorax +campanulate, with delicate network of large, regular, hexagonal pores. +Mouth scarcely constricted, with nine parallel, vertical, conical feet, +about as long as the cephalis. (In the specimen figured by Ehrenberg only +seven feet are represented, two being broken off; two other specimens of +this species, captured by Rabbe, exhibited nine regularly disposed feet.) + +_Dimensions._--Cephalis 0.03 long, 0.02 broad; thorax 0.08 long, 0.1 broad. + +_Habitat._--Indian Ocean, Zanzibar (Pullen); Madagascar (Rabbe), surface. + + +{1271}6. _Anthocyrtis lauranthus_, n. sp. + +Shell smooth with slight collar stricture. Length of the two joints = +1 : 3, breadth = 1 : 4. Cephalis ovate, with large, roundish pores, and a +conical horn of twice the length. Thorax inflated, campanulate, with +regular, circular, hexagonally framed pores. Mouth two-thirds as broad, +little constricted, with nine parallel, vertical, broad, lamellar, +triangular feet, half as long as the cephalis. + +_Dimensions._--Cephalis 0.04 long, 0.03 broad; thorax 0.1 long, 0.12 broad. + +_Habitat._--Central Pacific, Station 266 to 270, depth 2550 to 2925 +fathoms. + + +7. _Anthocyrtis grossularia_, Ehrenberg. + + _Anthocyrtis grossularia_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 64, Taf. vi. fig. 6. + +Shell spiny, with deep collar stricture. Length of the two joints = 1 : 5, +breadth = 1 : 4. Cephalis subspherical, thorny, with a conical horn of the +same length. Thorax ovate, spiny, with numerous densely-crowded, +subregular, circular pores. Mouth about half as broad, constricted, with +nine parallel, vertical, slender, conical feet, about as long as the +cephalis. + +_Dimensions._--Cephalis 0.04 long, 0.05 broad; thorax 0.2 long, 0.18 broad. + +_Habitat._--Fossil in Barbados. + + +8. _Anthocyrtis subglobosa_, n. sp. + +Shell spiny, with deep collar stricture. Length of the two joints = 1 : 7, +breadth = 1 : 7. Cephalis subspherical, with a conical horn twice the +length. Thorax nearly spherical, with small and very numerous, regular, +circular pores. Mouth only one-third as broad, constricted, with nine +parallel, vertical, square, lamellar feet, about twice as long as the +cephalis. + +_Dimensions._--Cephalis 0.03 long, 0.035 broad; thorax 0.2 long, 0.2 broad. + +_Habitat._--South Pacific, Station 297, depth 1775 fathoms. + + + +Subgenus 3. _Anthocyrtura_, Haeckel. + +_Definition._--Feet of the peristome-corona convergent, their basal +distance greater than their terminal distance. + + +9. _Anthocyrtis enneaphylla_, n. sp. + +Shell smooth, with sharp collar stricture. Length of the two joints = +1 : 6, breadth = 1 : 5. Cephalis subspherical, with a conical horn twice +the length, nearly hyaline, with very small and scarce pores. Thorax nearly +spherical, with regular, circular, quincuncial pores. Mouth only {1272}half +as broad, with nine broad, triangular feet, twice as long as the cephalis, +and curved inwards, convergent towards the main axis. + +_Dimensions._--Cephalis 0.02 long, 0.025 broad; thorax 0.11 long, 0.12 +broad. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +10. _Anthocyrtis ovata_, n. sp. (Pl. 62, fig. 13). + +Shell smooth, with slight collar stricture. Length of the two joints = +1 : 5, breadth = 1 : 3. Cephalis ovate, with numerous small pores, and an +excentric conical horn of the same length. Thorax ovate, with regular, +circular, quincuncial pores. Mouth nearly of the same breadth, scarcely +constricted, with nine triangular, widely-separated feet, about as long as +the cephalis, and convergent towards the main axis. + +_Dimensions._--Cephalis 0.035 long, 0.03 broad; thorax 0.15 long, 0.1 +broad. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + + +Genus 567. _Anthocyrtium_,[184] n. gen. + +_Definition._--#Sethophormida# (vel Dicyrtida multiradiata aperta) without +thoracic ribs, with numerous terminal feet around the mouth (twelve to +fifteen or more). Cephalis free, with an apical horn. + +The genus _Anthocyrtium_ has been derived from the two preceding genera by +further multiplication of the terminal feet, the number of which is at +least twelve to fifteen, often twenty or more. It may be that some species +have arisen directly from _Patagospyris_ by loss of the sagittal ring. + + + +Subgenus 1. _Anthocyrtarium_, Haeckel. + +_Definition._--Feet of the peristome-corona divergent, their basal distance +less than their terminal distance. + + +1. _Anthocyrtium chrysanthemum_, n. sp. (Pl. 62, fig. 14). + +Shell smooth, with distinct collar stricture. Length of the two joints = +3 : 7, breadth = 4 : 9. Cephalis hemispherical, with small, circular pores, +and a large, straight, cylindro-conical horn, about as long as the shell. +Thorax campanulate, hemispherical, with six to eight transverse rows of +squarish pores, increasing in size downwards. Mouth little constricted, +with twelve to fifteen divergent, curved, slender feet, about as long as +the thorax. + +_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.07 long, 0.09 +broad. + +_Habitat._--Central Pacific, Station 270 to 274, depth 2350 to 2925 +fathoms. + + +{1273}2. _Anthocyrtium centaurea_, Haeckel. + + _Anthocyrtis mespilus_, var. _major_, Ehrenberg, 1875, Abhandl. d. k. + Akad. d. Wiss. Berlin, p. 66, Taf. vi. fig. 5. + +Shell smooth, with sharp collar stricture. Length of the two joints = +2 : 6, breadth = 3 : 7. Cephalis hemispherical, with irregular, roundish +pores, and a very large pyramidal horn, longer than the shell, with +contorted edges. Thorax hemispherical, with six to eight transverse rows of +regular, circular pores of equal size. Mouth little constricted, with +fifteen to twenty divergent, curved, slender feet, about as long as the +shell. + +_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.06 long, 0.07 +broad. + +_Habitat._--Fossil in Barbados. + + +3. _Anthocyrtium anthemis_, n. sp. + +Shell papillate, with obliterated collar stricture. Length of the two +joints = 1 : 3, breadth = 1 : 3. Cephalis hemispherical, with very small +and scarce pores, and a conical horn of the same length. Thorax conical, as +long as broad, with conical papillae, and eight to ten transverse rows of +roundish pores, gradually increasing in size downwards. Mouth scarcely +constricted, with fifteen to twenty divergent, straight, conical feet, half +as long as the thorax. + +_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.09 long, 0.09 +broad. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +4. _Anthocyrtium collare_, Haeckel. + + _Anthocyrtis collaris_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 64, Taf. vi. fig. 8. + +Shell rough, conical, with obliterated collar stricture. Length of the two +joints = 3 : 5, breadth = 4 : 7. Cephalis conical, with a pyramidal horn of +the same length, and with two transverse rows of rather oblong, narrow +pores. Thorax truncate, conical, in the lower part thorny, with six to +eight transverse rows of regular, circular pores, increasing in size +downwards. + +_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.05 long, 0.07 +broad. + +_Habitat._--Fossil in Barbados. + + +5. _Anthocyrtium adonis_, n. sp. (Pl. 62 fig. 20). + +Shell rough, with sharp collar stricture. Length of the two joints = +3 : 10, breadth = 4 : 12. Cephalis subspherical, with very small circular +pores, and a very long, straight cylindrical, horn, twice to three times as +long as the shell. Thorax inflated, ovate, or subspherical, with small +regular, circular, hexagonally-framed pores. Mouth strongly constricted, +half as broad as the thorax, with fifteen to {1274}twenty divergent, broad, +lamellar, rectangular feet, as long as the thorax, and so densely placed +that their margins come in contact with one another. + +_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.1 long, 0.12 broad. + +_Habitat._--Central Pacific, Station 263 to 268, depth 2650 to 3000 +fathoms. + + +6. _Anthocyrtium anemone_, n. sp. + +Shell spiny, with sharp collar stricture. Length of the two joints = 1 : 5, +breadth = 1 : 4. Cephalis subspherical, with a conical horn of half the +length, hyaline, without pores. Thorax spiny, pear-shaped, inflated, with +small and numerous, regular, circular pores. Mouth constricted, half as +broad as the thorax, with twelve to fifteen divergent, slender, conical, +denticulate feet, half as long as the thorax. + +_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.14 long, 0.12 +broad. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms; also fossil +in Barbados. + + + +Subgenus 2. _Anthocyrtonium_, Haeckel. + +_Definition._--Feet of the peristome-corona parallel, vertical; their basal +and apical distances equal. + + +7. _Anthocyrtium campanula_, n. sp. (Pl. 62, fig. 17). + +Shell smooth, with deep collar stricture. Length of the two joints = 1 : 3, +breadth = 1 : 3. Cephalis spherical, with a conical horn of the same +length. Thorax campanulate, thin-walled, with delicate network of regular, +hexagonal pores and thin bars. Mouth little constricted, with twenty to +twenty-four parallel, vertical, lanceolate feet, about as long as the +cephalis. + +_Dimensions._--Cephalis 0.03 diameter, thorax 0.09 long, 0.1 broad. + +_Habitat._--South Pacific, Station 302, depth 1450 fathoms. + + +8. _Anthocyrtium reticulatum_, Haeckel. + + _Thyrsocyrtis reticulata_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 84, Taf. xii. fig. 10. + +Shell rough, with sharp collar stricture. Length of the two joints = 1 : 2, +breadth = 1 : 3. Cephalis hemispherical, with a prismatic, denticulate horn +of the same length, and small, irregular pores. Thorax campanulate, thorny, +thin-walled, with delicate network of irregular, polygonal pores. Mouth +little constricted, with twelve (or more) small, parallel, vertical, +triangular feet, shorter than the cephalis. + +_Dimensions._--Cephalis 0.015 long, 0.02 broad; thorax 0.04 long, 0.06 +broad. + +_Habitat._--Fossil in Barbados. + + +{1275}9. _Anthocyrtium leptostylum_, Haeckel. + + _Anthocyrtis leptostyla_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 64, Taf. vi. fig. 1. + +Shell thorny, with slight collar stricture. Length of the two joints = +1 : 5, breadth = 2 : 4. Cephalis hemispherical, with small, scarce pores +and a slender conical horn of the same length. Thorax spiny, with regular, +circular, quincuncial pores. Mouth constricted, half as broad, with twelve +to eighteen slender, parallel, vertical feet, about as long as the +cephalis. + +_Dimensions._--Cephalis 0.02 long, 0.04 broad; thorax 0.1 long, 0.08 broad. + +_Habitat._--Central Pacific, Stations 266 to 270, depth 2550 to 2925 +fathoms; also fossil in Barbados. + + +10. _Anthocyrtium hispidum_, Haeckel. + + _Anthocyrtis hispida_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 64, Taf. viii. fig. 2. + + _Anthocyrtis hispida_, Buetschli, 1882, Zeitschr. f. wiss. Zool., vol. + xxxvi. p. 540, Taf. xxxiii. fig. 30. + +Shell thorny, with sharp collar stricture. Length of the two joints = +1 : 4, breadth = 2 : 5. Cephalis hemispherical, hyaline, with few very +small pores, or without any; with a stout conical horn of twice the length. +Thorax spiny, with regular, circular, hexagonally-framed pores (half as +broad as the bars between them). Mouth wide open, scarcely constricted, +with twelve to fifteen parallel, vertical, broad, lamellar, rectangular +feet, reaching nearly the length of the thorax. + +_Dimensions._--Cephalis 0.02 to 0.03 long, 0.03 to 0.05 broad; thorax 0.07 +to 0.09 long, 0.1 to 0.12 broad. + +_Habitat._--Central Pacific, Stations 263 to 265, depth 2650 to 3000 +fathoms; also fossil in Barbados. + + +11. _Anthocyrtium turris_, n. sp. + +Shell thorny, very similar to _Calocyclas turris_, Ehrenberg (1875, _loc. +cit._, Taf. xviii. fig. 7), but without fenestrated abdomen. Collar +stricture deep. Length of the two joints = 1 : 3, breadth = 1 : 3. Cephalis +subspherical, hyaline, without pores, with a stout conical horn of twice +the length. Thorax nearly spherical, spiny, with regular, circular, +quincuncial pores. Mouth little constricted, with fifteen to twenty +parallel, vertical, broad, lamellar, rectangular feet, about as long as the +thorax. + +_Dimensions._--Cephalis 0.03 long, 0.03 broad; thorax 0.1 long, 0.1 broad. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +{1276}12. _Anthocyrtium doronicum_, n. sp. (Pl. 62, fig. 18). + +Shell rough, with sharp collar stricture. Length of the two joints = 1 : 5, +breadth = 1 : 3. Cephalis hemispherical, with small, circular pores and a +stout conical horn of twice the length. Thorax campanulate, subcylindrical, +with regular, circular, quincuncial pores, three to four times as broad as +the bars. Mouth scarcely constricted, with twenty-four to thirty vertical, +nearly parallel, little curved feet, which are about half as long as the +shell, broad, lamellar, rectangular, and in close contact with their edges. + +_Dimensions._--Cephalis 0.025 long, 0.035 broad, thorax 0.12 long, 0.1 +broad. + +_Habitat._--South Pacific, Station 295, depth 1500 fathoms. + + + +Subgenus 3. _Anthocyrturium_, Haeckel. + +_Definition._--Feet of the peristome-corona convergent, their basal +distance greater than their apical distance. + + +13. _Anthocyrtium pyrum_, n. sp. (Pl. 62, fig. 12). + +Shell smooth, with obliterated collar stricture. Length of the two joints = +2 : 7, breadth = 3 : 8. Cephalis hemispherical, with a small, +bristle-shaped horn of half the length. Thorax inflated, subglobose, with +regular, circular, quincuncial pores and thin bars. Mouth constricted, only +half as broad, with fifteen to twenty small, triangular, convergent feet, +shorter than the cephalis. (In another specimen the feet were twice as +long, stronger and more convergent, than in the one figured.) + +_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.07 long, 0.8 broad. + +_Habitat._--North Pacific, Station 241, depth 2300 fathoms. + + +14. _Anthocyrtium setosum_, Haeckel. + + _Anthocyrtis setosa_, Haeckel, 1862, Monogr. d. Radiol., p. 311. + + ? _Lithopera setosa_, Ehrenberg, 1854, Mikrogeol., Taf. xxxv. B., B. iv. + fig. 23. + +Shell spiny, with sharp collar stricture. Length of the two joints = 1 : 2, +breadth = 1 : 3. Cephalis hemispherical, with a conical horn of the same +length and some accessory spines. Thorax campanulate, with subregular, +circular pores. Mouth little constricted, with twenty to thirty small, +triangular, convergent feet, about as long as the cephalis. (In Ehrenberg's +incomplete figure they are mostly broken off.) + +_Dimensions._--Cephalis 0.02 long, 0.02 broad; thorax 0.04 long, 0.06 +broad. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + +{1277}15. _Anthocyrtium ehrenbergii_, Haeckel. + + _Anthocyrtis ehrenbergii_, Stoehr, 1880, Palaeontogr., vol. xxvi. p. 100, + Taf. iii. fig. 21, _a_, _b._ + +Shell smooth, with obliterated collar stricture. Length of the two joints = +3 : 10, breadth = 2 : 8. Cephalis subcylindrical, with an excentric, stout, +pyramidal horn of the same length. Thorax bottle-shaped, with small, +regular, circular pores of equal size. Mouth little constricted, with +twenty to thirty small, triangular, convergent feet, about half as long as +the cephalis. + +_Dimensions._--Cephalis 0.03 long, 0.02 broad; thorax 0.1 long, 0.08 broad. + +_Habitat._--Fossil in Tertiary rocks of Sicily (Grotte), Stoehr. + + +16. _Anthocyrtium zanguebaricum_, Haeckel. + + _Anthocyrtis zanguebarica_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 285, Taf. ix. fig. 12. + +Shell smooth, with slight collar stricture. Length of the two joints = +3 : 10, breadth = 2 : 7. Cephalis subspherical, with an excentric conical +horn of the same length. Thorax slender, ovate or bottle-shaped, with +irregular, roundish pores increasing in size downwards. Mouth little +constricted, with twelve to fifteen small, triangular, convergent feet, +about half as long as the cephalis. + +_Dimensions._--Cephalis 0.03 long, 0.02 broad; thorax 0.1 long, 0.07 broad. + +_Habitat._--Indian Ocean (Zanzibar), depth 2200 fathoms, Pullen. + + +17. _Anthocyrtium ficus_, Haeckel. + + _Anthocyrtis ficus_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 64, Taf. vi. fig. 3. + +Shell rough, with obliterated collar stricture. Length of the two joints = +2 : 12, breadth = 3 : 10. Cephalis conical, with a large, cylindrical horn, +pyramidal at the base, about as long as the thorax. Thorax subovate, +truncate, papillate, with small, regular, circular, quincuncial pores of +the same breadth as the bars. Mouth constricted, two-thirds as broad as the +thorax, with fifteen to twenty strongly convergent, lamellar, rectangular +or sword-shaped feet, nearly as long as the thorax. + +_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.12 long, 0.1 broad. + +_Habitat._--Fossil in Barbados. + + +18. _Anthocyrtium flosculus_, n. sp. (Pl. 62, fig. 19). + + _Anthocyrtis flosculus_, Haeckel, 1881, Prodromus et Atlas, pl. lxii. + fig. 19. + +Shell ribbed, with distinct collar stricture. Length of the two joints = +1 : 4, breadth = 2 : 4. Cephalis hemispherical, with small, circular pores +and a large cylindrical horn, twice as long as the thorax and half as broad +at the base as the cephalis. Thorax subovate, truncate, with twenty-four to +thirty longitudinal ribs and alternating rows of circular pores. Mouth +constricted, two-thirds {1278}as broad as the thorax, with twenty-four to +thirty slender, convergent feet, which are as long as the entire shell, +with their edges in close contact and their distal ends pointed. + +_Dimensions._--Cephalis 0.03 long, 0.05 broad; thorax 0.12 long, 0.12 +broad. + +_Habitat._--Central Pacific, Stations 265 to 274, depth 2350 to 2925 +fathoms. + + + +Genus 568. _Anthocyrtidium_,[185] Haeckel, 1881, Prodromus, p. 431. + +_Definition._--#Sethophormida#, (vel Dicyrtida multiradiata aperta) without +thoracic ribs, with numerous (twelve to fifteen or more) subterminal feet, +which are separated from the constricted mouth by a ring of lattice-work. +Cephalis free, with an apical horn. + +The genus _Anthocyrtidium_ has been derived from the preceding +_Anthocyrtium_ by further growth and constriction of the peristome, which +becomes separated from the subterminal corona of feet by a more or less +broad ring of lattice-work. + + +1. _Anthocyrtidium cineraria_, n. sp. (Pl. 62, fig. 16). + +Shell campanulate, smooth, with obliterated collar stricture. Length of the +two joints = 5 : 11, breadth = 3 : 13. Cephalis subcylindrical-ovate, with +a conical straight horn of half the length. Thorax hemispherical, inflated, +nearly twice as broad as the constricted mouth. Pores subregular, circular, +double-contoured. Above the mouth, separated from it by two rows of pores, +a corona of twelve to fifteen short conical feet, which are directed +downwards, slightly curved, and as long as the cephalic horn. + +_Dimensions._--Cephalis 0.05 long, 0.03 broad; thorax 0.11 long, 0.13 +broad. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +2. _Anthocyrtidium ligularia_, n. sp. (Pl. 62, fig. 15). + +Shell campanulate, rough, with distinct collar stricture. Length of the two +joints = 1 : 4, breadth = 2 : 6. Cephalis hemispherical, with a slender, +conical, slightly curved horn, about as long as the shell. Thorax +hemispherical, three times as broad as the cephalis, nearly twice as broad +as the constricted mouth, which is prolonged into a prominent smooth ring. +Above the mouth, separated from it by one row of pores, a corona of twelve +to fifteen slender linear feet, which are slightly curved, divergent, and +emarginate at the truncated distal end. + +_Dimensions._--Cephalis 0.015 long, 0.03 broad; thorax 0.06 long, 0.09 +broad. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +{1279}3. _Anthocyrtidium matricaria_, n. sp. + +Shell campanulate, rough, very similar to the preceding species, but +differing in the straight, large, pyramidal horn of the cephalis (as long +as the shell), and in the longer feet, which are twelve to fifteen in +number, little curved at the distal end, pointed, and about as long as the +shell. Length of the two joints = 2 : 6, breadth = 3 : 8. Differs from the +similar _Anthocyrtium centaurea_, Ehrenberg (1875, _loc. cit._, Taf. vi. +fig. 5), mainly in the prominent ring of the peristome. + +_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.06 long, 0.08 +broad. + +_Habitat._--Fossil in Barbados. + + + +Genus 569. _Carpocanium_,[186] Ehrenberg, 1847, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 54. + +_Definition._--#Sethophormida# (vel Dicyrtida multiradiata aperta) without +thoracic ribs, with numerous terminal feet around the mouth (six to twelve +or more). Cephalis hidden in the thorax, without apical horn. + +The genus _Carpocanium_, very common, and rich in numerous living and +fossil species, was formerly placed by me among the true Monocyrtida, since +an external constriction is not visible (Monogr., 1862, p. 290). Afterwards +(in 1879) Richard Hertwig demonstrated that the cavity of the ovate shell, +externally simple, is divided by an internal transverse septum into two +joints, the upper of which is the flat rudimentary cephalis (Organism. d. +Radiol., p. 79; compare also Buetschli, 1882, _loc. cit._, p. 535). Indeed +this septum, with four central crossed cortinar beams, is a true collar +septum, and _Carpocanium_ has been derived from _Anthocyrtis_ or +_Desmospyris_ by reduction of the cephalis, which is very flat and +perfectly hidden in the uppermost part of the thorax. The apical horn is +lost. If the internal septum were to become lost, the genus would pass over +into _Carpocanistrum_. + + + +Subgenus 1. _Carpocanarium_, Haeckel. + +_Definition._--Peristome-corona composed of six feet (three primary +perradial alternating with three secondary interradial). + + +1. _Carpocanium calycodes_, Stoehr. + + _Carpocanium calycodes_, Stoehr, 1880, Palaeontogr., vol. xxvi. p. 96, + Taf. iii. fig. 8. + +Shell urceolate, smooth, nearly twice as long as broad, with hemispherical +vaulted cephalis. Length of the two joints = 3 : 16, breadth = 5 : 10. +Pores regular, circular, as broad as the bars, {1280}quincuncially disposed +in about five longitudinal series at each side. Mouth constricted, half as +broad as the thorax. Peristome with six vertical, equilateral, triangular +feet. + +_Dimensions._--Cephalis 0.015 long, 0.025 broad; thorax 0.08 long, 0.05 +broad. + +_Habitat._--Fossil in Tertiary rocks of Sicily (Grotte, Caltanisetta). + + +2. _Carpocanium setosum_, Haeckel. + + _Halicalyptra setosa_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 160, Taf. ii. fig. 12. + +Shell ovate, truncate at the mouth, thorny, exactly as long as broad. +Length of the two joints = 1 : 8, breadth = 3 : 9. Cephalis hidden, with +very small pores. Thorax inflated, with regular, circular pores, twice as +broad as the bars, in about ten longitudinal series at each side. Mouth +constricted, half as broad as the thorax. Peristome with six vertical, +parallel, broad, lamellar, rectangular feet, separated by equal internals, +half as long as the shell. + +_Dimensions._--Cephalis 0.01 long, 0.03 broad; thorax 0.08 long, 0.09 +broad. + +_Habitat._--Fossil in Barbados. + + +3. _Carpocanium laeve_, Ehrenberg. + + _Carpocanium laeve_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 287. + +Shell subspherical, smooth, equal in length and breadth, with little +vaulted, cap-shaped cephalis. Length of the two joints = 1 : 6, breadth = +4 : 7. Pores regular, circular, twice as broad as the bars, in nine +longitudinal rows. Mouth constricted, only one-third as broad as the +thorax. Peristome with six strong conical feet, which are slightly curved +and convergent. + +_Dimensions._--Cephalis 0.01 long, 0.04 broad; thorax 0.06 long, 0.07 +broad. + +_Habitat._--Mediterranean (Greece); Tropical Atlantic, Station 348, depth +2450 fathoms. + + +4. _Carpocanium lanceolatum_, n. sp. + +Shell subspherical, thorny, with perfectly hidden cephalis. Length of the +two joints = 1 : 3, breadth = 1 : 3. Pores regular, circular, hexagonally +framed, half as broad as the bars, in about sixteen longitudinal rows at +each side. Mouth constricted, half as broad as the thorax. Peristome with +six large lanceolate, vertical, lamellar feet, half as long as the shell. + +_Dimensions._--Cephalis 0.03 long, 0.03 broad; thorax 0.09 long, 0.09 +broad. + +_Habitat._--South Pacific, Station 300, depth 1375 fathoms. + + + +Subgenus 2. _Carpocanidium_, Haeckel. + +_Definition._--Peristome-corona composed of nine feet (three primary +perradial and six secondary interradial). + + +{1281}5. _Carpocanium diadema_, Haeckel. + + _Carpocanium diadema_, Haeckel, 1862, Monogr. d. Radiol., p. 290, Taf. v. + fig. 1. + + _Carpocanium diadema_, R. Hertwig, 1879, Organism. d. Radiol., p. 79, + Taf. viii. figs. 7, 7_a_, 8, 8_a_, 8_b_. + +Shell ovate, with little vaulted cephalis. Length of the two joints = +1 : 8, breadth = 3 : 6. Pores regular, circular, in about twelve +longitudinal rows, twice as broad as the bars. Mouth constricted, half as +broad as the thorax. Peristome with nine vertical, equilateral, triangular +feet. + +_Dimensions._--Cephalis 0.01 long, 0.03 broad; thorax 0.08 long, 0.06 +broad. + +_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Indian, Pacific; many +stations, surface. + + +6. _Carpocanium cylindricum_, n. sp. + +Shell cylindrical, with hemispherical, flatly vaulted cephalis. Length of +the two joints = 1 : 4, breadth = 3 : 3. Pores regular, circular, +double-contoured, as broad as the bars, in about fifteen longitudinal +series. Mouth constricted, two-thirds as broad as the thorax. Peristome +with nine vertical, slender, triangular, pointed feet. + +_Dimensions._--Cephalis 0.02 long, 0.06 broad; thorax 0.08 long, 0.06 +broad. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +7. _Carpocanium enneaphyllum_, n. sp. + +Shell slenderly ovate, at the mouth truncate, thorny, with hemispherical, +vaulted cephalis. Length of the two joints = 1 : 6, breadth = 2 : 4. Pores +regular, circular, hexagonally framed, as broad as the bars, in about +thirteen longitudinal rows. Mouth constricted, about two-thirds as broad as +the thorax. Peristome with nine broad, lamellar, vertical, nearly square +feet, half as long as the shell, with small intervals. + +_Dimensions._--Cephalis 0.02 long, 0.04 broad; thorax 0.12 long, 0.09 +broad. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +8. _Carpocanium solitarium_, Ehrenberg. + + _Carpocanium solarium_, Ehrenberg, 1854, Mikrogeol., Taf. xxii. fig. 28. + + _Lithocampe solitaria_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, p. 65. + +Shell slenderly ovate, twice as long as broad, with hidden spherical +cephalis, completely enclosed in the summit of the thorax. Length of the +two joints = 1 : 6, breadth = 1 : 4. Pores small, regular, circular, as +broad as the bars, in about eleven longitudinal rows. Mouth gradually +constricted, half as broad as the thorax. Peristome with nine ovate blunt +feet, which are as long as the cephalis, little curved and convergent. + +_Dimensions._--Cephalis 0.02 long, 0.02 broad; thorax 0.12 long, 0.07 +broad. + +_Habitat._--Fossil in Tertiary rocks of Sicily (Caltanisetta). + + +{1282}9. _Carpocanium gemmula_, n. sp. + +Shell subspherical, smooth, equal in length and breadth, with hemispherical +vaulted cephalis. Length of the two joints = 2 : 7, breadth = 4 : 9. Pores +small, regular, circular, twice as broad as the bars, in about twenty +longitudinal rows. Mouth strongly constricted, only one-fourth as broad as +the thorax. Peristome with nine conical feet, which are twice as long as +the cephalis, curved, and so convergent that their distal ends come nearly +in contact. + +_Dimensions._--Cephalis 0.02 long, 0.04 broad; thorax 0.07 long, 0.09 +broad. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +10. _Carpocanium microdon_, Ehrenberg. + + _Carpocanium microdon_, Ehrenberg, 1858, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, p. 30. + +Shell broad, ovate, rough, with perfectly hidden cephalis. Length of the +two joints = 2 : 9, breadth = 4 : 7. Pores very small and scarce, smaller +than the bars between them, irregularly scattered. Mouth constricted, +one-third as broad as the thorax. Peristome with nine short, triangular, +pointed, convergent feet. + +_Dimensions._--Cephalis 0.02 long, 0.04 broad; thorax 0.09 long, 0.07 +broad. + +_Habitat._--Mediterranean (Crete), Atlantic (Canary Islands), Station 354, +surface. + + + +Subgenus 3. _Carpocanobium_, Haeckel. + +_Definition._--Peristome-corona composed of twelve or more feet. + + +11. _Carpocanium trepanium_, n. sp. (Pl. 52, fig. 18). + +Shell subcylindrical, with flatly vaulted cephalis. Length of the two +joints = 1 : 6, breadth = 3 : 4. Pores regular, hexagonal, four to six +times as broad as the bars. Mouth little constricted, two-thirds as broad +as the thorax. Peristome with eighteen to twenty-four large, slender, +triangular, vertical feet. + +_Dimensions._--Cephalis 0.02 long, 0.06 broad; thorax 0.12 long, 0.08 +broad. + +_Habitat._--Indian Ocean, Madagascar (Rabbe), surface. + + +12. _Carpocanium hexagonale_, n. sp. (Pl. 52, fig. 15). + +Shell broadly ovate or subconical, with vaulted, cap-shaped cephalis. +Length of the two joints = 2 : 7, breadth = 6 : 9. Thorax subglobular, +truncate. Pores subregular, hexagonal, three to four times as broad as the +bars. Mouth constricted, two-thirds as broad as the thorax. Peristome with +twenty to twenty-five small, triangular, vertical feet. + +_Dimensions._--Cephalis 0.02 long, 0.05 broad; thorax 0.07 long, 0.09 +broad. + +_Habitat._--Tropical Atlantic, Station 347, surface. + + +{1283}13. _Carpocanium petalospyris_, n. sp. (Pl. 52, fig. 19). + +Shell subspherical, smooth, with perfectly hidden cephalis. Length of the +two joints = 1 : 6, breadth = 3 : 6. Pores regular, circular, hexagonally +framed, twice as broad as the bars, in about sixteen longitudinal rows. +Mouth slightly constricted, little narrower than the thorax. Peristome with +twenty to twenty-four vertical, broad, lamellar feet, which are nearly as +long as the shell, at the distal end truncate, and almost in contact at +their edges. + +_Dimensions_.--Cephalis 0.02 long, 0.05 broad; thorax 0.11 long, 0.12 +broad. + +_Habitat_.--Central Pacific, Station 271, depth 2425 fathoms. + + +14. _Carpocanium polypterum_, Haeckel. + + _Cryptoprora polyptera_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 287, Taf. ix. fig. 17. + + _Carpocanium macropterum_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 302. + +Shell campanulate-conical, smooth, with perfectly hidden cephalis. Length +of the two joints = 1 : 6, breadth = 4 : 6. Pores regular, circular, twice +as broad as the bars, in about sixteen longitudinal rows. Mouth wide open, +not constricted. Peristome with twenty to thirty vertical, slender, conical +feet, about as long as the shell. + +_Dimensions_.--Cephalis 0.01 long, 0.04 broad; thorax 0.06 long, 0.06 +broad. + +_Habitat_.--Indian Ocean (Zanzibar), depth 2200 fathoms (Pullen). + + +15. _Carpocanium palmipes_, n. sp. + +Shell ovate, very thick-walled, smooth. Lower half of the subspherical +cephalis hidden in the summit of the thorax, upper half free, with few +small pores. Length of the two joints = 3 : 10, breadth = 3 : 10. Thorax +foveolate, with oblong dimples, each of which encloses a small, circular, +double-contoured pore, half as broad as the bars. Mouth little constricted, +nearly as broad as the thorax. Peristome prolonged into a solid, +cylindrical tube, nearly as long and as broad as the shell; the upper half +of the tube is solid, the lower divided into from twelve to fifteen +vertical, lamellar, pointed feet. + +_Dimensions_.--Cephalis 0.03 long, 0.03 broad; thorax 0.1 long, 0.1 broad. + +_Habitat_.--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +16. _Carpocanium peristomium_, n. sp. (Pl. 52, figs. 16, 17). + +Shell ovate, smooth, with perfectly hidden, flat cephalis (fig. 17). Length +of the two joints = 2 : 10, breadth = 5 : 9. Pores small and very numerous, +regular, circular, as broad as the bars, in about twenty longitudinal rows. +Mouth little constricted. Peristome broad; in the upper {1284}half a +hyaline, circular ring, in the lower half divided into from eighteen to +twenty-four triangular, curved, little convergent feet. + +_Dimensions._--Cephalis 0.02 long, 0.05 broad; thorax 0.1 long, 0.09 broad. + +_Habitat._--Cosmopolitan; Atlantic, Indian, Pacific; many stations, at +various depths. + + +17. _Carpocanium coronatum_, Ehrenberg. + + _Carpocanium coronatum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 66, Taf. v. fig. 7. + +Shell ovate, smooth, with perfectly hidden, subspherical cephalis. Length +of the two joints = 2 : 9, breadth = 2 : 8. Pores small and very numerous, +twice as broad as the bars, regular, circular, in about twenty longitudinal +rows. Mouth little constricted, two-thirds as broad as the thorax. +Peristome with twenty-five to thirty short, bristle-shaped feet, which are +slightly curved, convergent, and in the upper half connected by a solid +ring. + +_Dimensions._--Cephalis 0.02 long, 0.02 broad; thorax 0.09 long, 0.08 +broad. + +_Habitat._--Fossil in Barbados. + + +18. _Carpocanium dactylus_, n. sp. + +Shell slenderly ovate, twice as long as broad, with flat, perfectly hidden +cephalis. Length of the two joints = 1 : 12, breadth = 4 : 8. Pores +subregular, circular, as broad as the bars, in about twelve longitudinal +rows, separated by prominent longitudinal ribs. Mouth constricted, +two-thirds as broad as the thorax. Peristome with twelve large, lanceolate, +lamellar, convergent feet. + +_Dimensions._--Cephalis 0.01 long, 0.04 broad; thorax 0.12 long, 0.08 +broad. + +_Habitat._--South Pacific, Station 295, depth 1500 fathoms. + + +19. _Carpocanium irregulare_, n. sp. (Pl. 52, fig. 14). + +Shell irregular, roundish, subovate, with flat and oblique, perfectly +hidden cephalis. Length of the two joints = 1 : 10, breadth = 3 : 9. Pores +irregularly scattered, roundish, about as broad as the bars. Mouth wide +open, not at all or little constricted. Peristome with twenty to thirty +long, lamellar, pointed feet, which are irregularly curved and convergent. + +_Dimensions._--Cephalis 0.01 to 0.02 long, 0.03 to 0.04 broad; thorax 0.09 +to 0.11 long, 0.08 to 0.09 broad. + +_Habitat._--Central Pacific, Station 263 to 274, surface, and at various +depths. + + +20. _Carpocanium verecundum_, n. sp. (Pl. 52, figs. 12, 13). + +Shell ovate, smooth, with flat, perfectly hidden cephalis (fig. 12). Length +of the two joints = 1 : 9, breadth = 4 : 9. Pores subregular, circular, +twice as broad as the bars, in about eighteen, {1285}partly interrupted, +longitudinal rows, separated by prominent crests. Mouth little constricted. +Peristome with twenty to twenty-four broad, lamellar, pointed feet, which +are about as long as the shell, little curved, and convergent. + +_Dimensions._--Cephalis 0.01 long, 0.04 broad; thorax 0.09 long, 0.09 +broad. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +21. _Carpocanium virgineum_, n. sp. (Pl. 52, fig. 20). + +Shell ovate, smooth, with flat perfectly hidden cephalis. Length of the two +joints = 1 : 8, breadth = 3 : 9. Pores regular, circular, hexagonally +framed, as broad as the bars, in about sixteen longitudinal rows on each +side. Mouth little constricted. Peristome with eighteen to twenty-four very +large, lamellar, pointed feet, which are longer than the shell, and so +curved and convergent that their distal points come nearly in contact. + +_Dimensions._--Cephalis 0.01 long, 0.03 broad; thorax 0.08 long, 0.09 +broad. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + + +Subfamily 2. SETHOPHAENIDA, Haeckel, 1881, Prodromus, p. 433. + +_Definition._--#Anthocyrtida# with the basal mouth of the shell fenestrated +(vel Dicyrtida multiradiata clausa). + + + +Genus 570. _Sethophaena_,[187] Haeckel, 1881, Prodromus, p. 433. + +_Definition._--#Sethophaenida# (vel Dicyrtida multiradiata clausa) with +lateral apophyses. Cephalis with a horn. + +The genus _Sethophaena_ and the following _Clistophaena_ form together the +small subfamily of Sethophaenida, comprising those Dicyrtida in which the +thorax bears numerous radial appendages (four to six or more), and the +mouth is closed by a lattice-plate. In _Sethophaena_ the apophyses are +lateral wings, as in _Micromelissa_, from which it may be derived by +development of secondary wings, interpolated between the three primary +wings. + + +1. _Sethophaena tetraptera_, n. sp. + +Shell smooth, with deep collar stricture. Length of the two joints = +3 : 10, breadth = 4 : 9. Cephalis subspherical, without horn. Thorax ovate, +with rounded hemispherical base, and subregular, hexagonal pores. From its +upper half (below the collar stricture) arise four divergent, +{1286}conical, straight wings, of half the length, opposite in pairs in two +meridional planes, perpendicular to one another (compare _Tetralacorys_, +Pl. 65, figs. 4, 5). + +_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.1 long, 0.09 broad. + +_Habitat._--South Pacific, Station 300, depth 1375 fathoms. + + +2. _Sethophaena hexaptera_, n. sp. (Pl. 97, fig. 13). + +Shell rough, pear-shaped, with distinct collar stricture. Length of the two +joints = 1 : 4, breadth = 2 : 4. Cephalis hemispherical, with a conical +horn of the same length. Thorax inflate, inversely ovate, nearly +pear-shaped, with subregular, circular pores. From its upper half arise, by +a broad base, six divergent, strong, conical wings, which are horn-like, +curved downwards, and half as long as the thorax. + +_Dimensions._--Cephalis 0.025 long, 0.04 broad; thorax 0.09 long, 0.08 +broad. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +3. _Sethophaena enneaptera_, n. sp. + +Shell rough, with sharp collar stricture. Length of the two joints = 1 : 6, +breadth = 1 : 3. Cephalis subspherical, with a stout conical horn of twice +the length. Thorax inversely ovate, with pointed, conical, basal part, and +irregular, roundish pores. From its middle part arise, by a broad +triangular base, nine compressed, divergent wings, which are a little +curved, slender, and about as long as the thorax. + +_Dimensions._--Cephalis 0.025 long, 0.03 broad; thorax 0.17 long, 0.1 +broad. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +4. _Sethophaena polyptera_, n. sp. + +Shell thorny, with slight collar stricture. Length of the two joints = +1 : 10, breadth = 3 : 8. Cephalis flat, cap-shaped, without horn. Thorax +pear-shaped, with hemispherical base and regular, circular pores. From its +lower half (beyond the equator) arises a corona of numerous short conical +wings (eighteen to twenty-four), which are a little curved, and divergent +downwards, scarcely one-third as long as the thorax. + +_Dimensions._--Cephalis 0.015 long, 0.04 broad; thorax 0.15 long, 0.12 +broad. + +_Habitat._--North Pacific, Station 253, depth 3125 fathoms. + + + +Genus 571. _Clistophaena_,[188] Haeckel, 1881, Prodromus, p. 433. + +_Definition._--#Sethophaenida# (vel Dicyrtida multiradiata clausa) with +terminal apophyses. Cephalis with a horn. + +{1287}The genus _Clistophaena_ agrees with the preceding _Sethophaena_ in +the mouth of the thorax being closed by a lattice-plate. But the appendages +of the thorax are terminal feet, not lateral wings; their number is +commonly six or nine, rarely more. _Clistophaena_ may be derived either +from _Tetrahedrina_ by interpolation of secondary feet between the three +primary, or from _Sethamphora_ by development of a basal lattice-plate +closing the mouth. + + +1. _Clistophaena ruestiana_, n. sp. (Pl. 57, fig. 6). + +Shell rough, with distinct collar stricture. Length of the two joints = +3 : 10, breadth = 4 : 11. Cephalis hemispherical, with small, circular +pores and a stout oblique horn three times the length, which is three-sided +prismatic, and at the top denticulate. Thorax subconical, inflate, with +regular, circular, quincuncial pores, increasing in size towards the base. +Margin of the flat base, with six divergent, stout feet of the same +prismatic form as the cephalic horn, with denticulate distal ends, about as +long as the thorax. This elegant species is dedicated to Dr. Ruest of +Freiburg, the discoverer of numerous fossil Radiolaria in the Liassic and +Jurassic formations. + +_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.1 long, 0.11 broad. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +2. _Clistophaena hexolena_, n. sp. + +Shell smooth, with slight collar stricture. Length of the two joints = +1 : 4, breadth = 1 : 5. Cephalis subspherical, small, with a large, +vertical, cylindrical horn, about as long as the shell, and small, circular +pores. Thorax nearly three-sided pyramidal or tetrahedral, with three +rounded edges and sub-regular, circular pores. Margin of the flat base with +six conical, divergent, straight feet, somewhat shorter than the thorax. +(Three on the corners, one on the middle of each side of the triangular +base.) + +_Dimensions._--Cephalis 0.03 diameter, thorax 0.12 long, 0.14 broad. + +_Habitat._--North Pacific, Station 241, depth 2300 fathoms. + + +3. _Clistophaena pyramidalis_, n. sp. + +Shell smooth, with slight collar stricture. Length of the two joints = +2 : 8, breadth = 3 : 10. Cephalis hemispherical, with a stout pyramidal +horn of twice the length. Thorax six-sided pyramidal, with regular, +circular pores of equal size, and six prominent, straight edges, which are +prolonged into six divergent, pyramidal feet of half the length. + +_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.08 long, 0.1 broad. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + +{1288}4. _Clistophaena armata_, n. sp. (Pl. 57, fig. 7). + +Shell spiny, with deep collar stricture. Length of the two joints = 4 : 18, +breadth = 5 : 15. Cephalis subspherical, with small, circular, +hexagonally-framed pores, and a stout, three-sided prismatic, cuspidate +horn of the same length. Thorax pear-shaped, with regular, circular pores +and three pairs of stout pyramidal wings, placed in the three primary +meridional planes of the collar beams; three of them lie in the upper, and +three in the lower third of the thorax. Margin of the flat base with nine +cylindrical, somewhat club-shaped, divergent feet. + +_Dimensions._--Cephalis 0.04 long, 0.05 broad; thorax 0.18 long, 0.15 +broad. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +5. _Clistophaena enneolena_, n. sp. + +Shell spiny, with sharp collar stricture. Length of the two joints = +4 : 20, breadth 5 : 16. Cephalis hemispherical, hyaline, with a stout +conical horn of the same length and some small accessory horns. Thorax +ovate, spiny, with subregular, circular pores. Margin of the vaulted base +with nine divergent, conical feet, half as long as the thorax. + +_Dimensions._--Cephalis 0.04 long, 0.05 broad; thorax 0.2 long, 0.16 broad. + +_Habitat._--South Pacific, Station 296, depth 1825 fathoms. + + +6. _Clistophaena polyolena_, n. sp. + +Shell smooth, conical, with obliterated collar stricture. Length of the two +joints = 1 : 5, breadth = 2 : 5. Cephalis hemispherical, with small, +circular pores and two divergent conical horns (a major occipital and a +smaller frontal horn). Thorax obtusely conical, with regular, hexagonal +pores at the mantle, and circular pores in the basal plate, the margin of +which bears eighteen vertical, parallel, conical feet, as long as the +cephalis. + +_Dimensions._--Cephalis 0.015 long, 0.025 broad; thorax 0.08 long, 0.08 +broad. + +_Habitat._--Central Pacific, Stations 271 to 274, depth 2350 to 2750 +fathoms. + + + +Family LXIV.--#SETHOCYRTIDA#, n. fam. + + _Sethocorida et Sethocapsida_, Haeckel, 1881, Prodromus, pp. 439, 433. + +_Definition._--#Dicyrtida# eradiata. (#Cyrtoidea# with a two-jointed shell, +divided by a transverse constriction into cephalis and thorax, without +radial apophyses). + +The family #Sethocyrtida#, composed of the Sethocorida and Sethocapsida of +my Prodromus, comprises those #Cyrtoidea# in which the shell is two-jointed +and bears no radial apophyses. The two subfamilies differ in the shape of +the mouth, which in the Sethocorida is a simple wide opening, and in the +Sethocapsida is closed by a lattice-plate. The former are here divided into +eight, the latter into three genera. + +{1289}Numerous living and fossil forms of Sethocyrtida were previously +described by Ehrenberg, partly in his genera _Dictyocephalus_ and +_Lophophaena_, partly (intermingled with three-jointed and many-jointed +forms) in the genera _Eucyrtidium_ and _Lithocampe_. A larger number of new +forms has been found in the Radiolarian ooze collected by the Challenger, +and others fossil in Barbados. Many of these Sethocyrtida are common and +widely distributed. When a new third joint is formed on their basal mouth, +they pass over into Theocyrtida. + +The cephalis is usually subspherical or hemispherical, and much smaller +than the thorax, the form of which exhibits all possible intermediate +stages between flat, discoidal, conical, cylindrical, and ovate forms. The +wide open mouth becomes more and more constricted, and finally closed in +the Sethocapsida. The majority of the Sethocyrtida may have been derived +either from the Tripocyrtida, or from the Anthocyrtida by reduction and +loss of the radial apophyses. + +_Synopsis of the Genera of Sethocyrtida._ + + ------------------------------------------------------------------------- + I. Subfamily Sethocorida. + Terminal mouth of the thorax a simple wide opening. + -------------------- + Thorax conical or campanulate, gradually dilated. + ------------------------------------------------------------------------- + Shell simple, without mantle, 572. _Sethoconus_. + + Shell double, with an arachnoid mantle, 573. _Periarachnium_. + ------------------------------------------------------------------------- + Thorax discoidal, flatly expanded. + ------------------------------------------------------------------------- + Cephalis very large, without horn, 574. _Sethocephalus_. + + { Mouth simple, 575. _Sethocyrtis_. + Cephalis with a single horn. { + { Mouth tubular, 576. _Sethocorys_. + ------------------------------------------------------------------------- + Thorax cylindrical or ovate, with truncate, constricted or tubular mouth. + ------------------------------------------------------------------------- + Cephalis with two horns or a bunch of horns, 577. _Lophophaena_. + + Cephalis without horn, 578. _Dictyocephalus_. + ------------------------------------------------------------------------- + II. Subfamily Sethocapsida. + Terminal mouth closed by a lattice-plate. + -------------------- + Cephalis free, not hidden in the thorax + ------------------------------------------------------------------------- + One horn, 579. _Sethocapsa_. + + No horn, 580. _Dicolocapsa_. + ------------------------------------------------------------------------- + Cephalis hidden in the upper part of the thorax. + ------------------------------------------------------------------------- + No horn, 581. _Cryptocapsa_. + + + +Subfamily 1. SETHOCORIDA, Haeckel, Prodromus, p. 430. + +_Definition._--#Sethocyrtida# with the basal mouth of the shell open (vel +Dicyrtida eradiata aperta). + + + +{1290}Genus 572. _Sethoconus_,[189] Haeckel, 1881, Prodromus, p. 430. + +_Definition._--#Sethocorida# (vel Dicyrtida eradiata aperta) with conical +or campanulate, gradually dilated thorax and wide open mouth. Cephalis with +one or more horns. + +The genus _Sethoconus_ is the oldest and simplest form of the Sethocorida, +or of those Dicyrtida in which the simple thorax bears no apophyses and has +the mouth open and not closed by a basal lattice-plate. Probably all those +eradiate Sethocorida have been derived either from triradiate Sethopilida +(_Lychnocanium_), or from multiradiate Sethophormida (_Sethophormis_, +_Anthocyrtis_ ?) by loss of the radial ribs and feet. In _Sethoconus_ the +thorax is more or less conical, sometimes more campanulate, commonly +smooth, in some species covered with spines. The cephalis is usually small, +with rudimentary collar septum, at other times large, with distinct +cortinar septum. Correspondingly, the genus may be divided into different +groups, which here are enumerated as subgenera. + + + +Subgenus 1. _Conarachnium_, Haeckel, 1881, Prodromus, p. 430. (= +_Ceratocyrtis_, Buetschli), 1882, _loc. cit._, p. 536. + +_Definition._--Cephalis relatively large, with distinct collar septum and +numerous pores. Thorax smooth. + + +1. _Sethoconus trochus_, Haeckel. + + _Eucyrtidium trochus_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 293, Taf. vii, fig. 17. + + _Conarachnium trochus_, Haeckel, 1881, Prodromus, p. 430. + +Cephalis ovate, relatively large, with a pyramidal horn of the same length, +and three pairs of large opposite pores, on each side of a vertical septum. +Thorax wide, conical, about as long as broad, with nearly straight +outlines; its pores regular, circular, hexagonally framed, of the same size +as the cephalic pores. + +_Dimensions._--Cephalis 0.03 long, 0.02 broad; thorax 0.06 long, 0.06 +broad. + +_Habitat._--Tropical Pacific, Stations 200 to 281, surface. + + +2. _Sethoconus cucullaris_, Haeckel. + + _Cornutella cucullaris_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 68, Taf. ii. fig. 7. + + _Ceratocyrtis cucullaris_, Buetschli, 1882, Zeitschr. f. wiss Zool., Bd. + xxvi. p. 536, Taf. xxxiii. fig. 36, _a._, _b._ + +Cephalis subspherical, thorny, relatively large, with a conical horn of the +same length, and small circular pores. Thorax wide, conical, enveloping the +lower hidden half of the cephalis, about as {1291}long as broad, with +slightly convex outlines; its pores subregular, circular, half as broad as +the cephalis. + +_Dimensions._--Cephalis 0.03 long, 0.02 broad; thorax 0.15 long, 0.14 +broad. + +_Habitat._--Fossil in Barbados. + + +3. _Sethoconus pileus_, n. sp. + +Cephalis subspherical, free, with distinct collar stricture, a conical +oblique horn of the same length, and small, irregular, roundish pores. +Thorax flatly conical, about half as long as broad, with straight outlines; +its pores subregular, hexagonal, half as broad as the cephalis, with very +thin bars. + +_Dimensions._--Cephalis 0.02 long, 0.02 broad; thorax 0.08 long, 0.16 +broad. + +_Habitat._--Central Pacific, Stations 262 to 274, surface. + + +4. _Sethoconus ampliatus_, Haeckel. + + _Cornutella ampliata_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 68, Taf. ii. fig. 5. + + _Ceratocyrtis ampliata_, Buetschli, 1882, Zeitschr. f. wiss. Zool., Bd. + xxxvi. p. 536. + +Cephalis, hemispherical, thorny, with a conical horn of twice the length; +it is separated from the thorax by a complete internal collar septum, but +without external collar stricture. Thorax flatly conical, about half as +long as broad, with straight outlines; its pores subregular, hexagonal, +about as large as the cephalis, with thin bars. + +_Dimensions._--Cephalis 0.015 long, 0.03 broad; thorax 0.08 long, 0.18 +broad. + +_Habitat._--Fossil in Barbados. + + +5. _Sethoconus mitra_, Haeckel. + + _Cornutella mitra_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 68, Taf. ii. fig. 8. + + _Ceratocyrtis mitra_, Buetschli, 1882, Zeitschr. f. wiss. Zool., Bd. + xxxvi. p. 536. + +Cephalis ovate, with slight collar stricture (not distinct enough in +Ehrenberg's figure), with few large pores, and a conical stout horn of the +same length. Thorax campanulate, conical, twice as long as broad, with +slightly convex outlines; its pores subregular, roundish, increasing in +size towards the mouth, the largest as broad as the cephalis. + +_Dimensions._--Cephalis 0.03 long, 0.02 broad; thorax 0.12 long, 0.07 +broad. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms; fossil in +Barbados. + + +6. _Sethoconus rayianus_, n. sp. (Pl. 58, fig. 6). + + _Conarachnium rayianum_, Haeckel, 1881, Prodromus, p. 430. + +Cephalis ovate, with obliterated collar stricture (but distinct internal +septum), with small, irregular pores, and two to four divergent horns, +which are longer than the cephalis, and two or three of which are forked. +Thorax tent-shaped, conical, two-thirds as long as broad, with slightly +{1292}concave outlines, and subregular, hexagonal pores, gradually +increasing towards the mouth, the largest half as broad as the cephalis. +This elegant species is dedicated to Dr. Ray, the discoverer of many rare +Radiolarians in the Challenger collection. + +_Dimensions._--Cephalis 0.03 long, 0.02 broad; thorax 0.08 long, 0.12 +broad. + +_Habitat._--Central Pacific, Stations 266 to 272, surface. + + +7. _Sethoconus cervus_, Haeckel. + + ? _Eucyrtidium cervus_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 291, Taf. ix. fig. 21. + + _Conarachnium cervus_, Haeckel, 1881, Prodromus, p. 430. + +Cephalis subspherical, with slight collar stricture, small circular pores, +and two to four divergent horns, one or two of which are forked. Thorax +wide, conical, about as long as broad, with straight outlines and +irregular, polygonal pores, gradually increasing towards the mouth; the +largest as broad as the cephalis. + +_Dimensions._--Cephalis 0.015 long, 0.02 broad; thorax 0.08 long, 0.08 +broad. + +_Habitat._--Indian Ocean; Maldive Islands, surface (Haeckel); Zanzibar, +depth 2200 fathoms (Pullen). + + +8. _Sethoconus lophophaena_, n. sp. + + _Conarachnium lophophaena_, Haeckel, 1881, Prodromus, p. 430. + +Cephalis subspherical, with distinct collar stricture, small circular +pores, and numerous (twelve to sixteen) radial, bristle-shaped horns of +different lengths. Thorax wide, conical, somewhat longer than broad, with +slightly convex outlines, and subregular, hexagonal pores, increasing +gradually in size towards the mouth; the largest twice as broad as the +cephalis. + +_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.2 long, 0.16 broad. + +_Habitat._--South Pacific, Station 300, depth 1375 fathoms. + + +9. _Sethoconus larvatus_, Haeckel. + + _Lophophaena larvata_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 78, Taf. viii. fig. 10. + + _Dictyocephalus larvatus_, Buetschli, 1882, Zeitschr. f. wiss. Zool., Bd. + xxxvi. p. 535. + +Cephalis subspherical, large, with sharp collar stricture, and numerous +(five to ten or more) radial, conical (partly forked) horns of different +lengths. Thorax wide, conical, somewhat broader than long, with straight +outlines. Pores of both joints very irregular, roundish, of very different +sizes and form. + +_Dimensions._--Cephalis 0.04 long, 0.05 broad; thorax 0.1 long, 0.12 broad. + +_Habitat._--Fossil in Barbados. + + +{1293}10. _Sethoconus nassa_, Haeckel. + + _Eucyrtidium nassa_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 72, Taf. ix. fig. 9. + +Cephalis slenderly ovate, with sharp collar stricture, few scattered pores, +and a very stout, pyramidal horn of the same length, which is surrounded at +the base by three short, divergent, ascending spines (perhaps the remnants +of the three cortinar rods of _Eucecryphalus_, &c. ?). Thorax slender, +conical, with straight outlines, and small, dense, regular, circular pores +of equal size. + +_Dimensions._--Cephalis 0.04 long, 0.02 broad; thorax 0.12 long, 0.08 +broad. + +_Habitat._--Fossil in Barbados. + + +11. _Sethoconus tabulatus_, Haeckel. + + _Cycladophora tabulata_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 289, Taf. iv. fig. 18. + +Cephalis subspherical, with slight collar stricture, and numerous small, +irregular pores, without horn, or with a small conical horn. Thorax +slenderly conical, with straight outlines, and large, regular, hexagonal +pores. Mouth truncate. (In the specimen I examined the thorax was longer +and more conically dilated; the cephalis had a distinct small horn.) + +_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.08 long, 0.06 +broad. + +_Habitat._--North Atlantic, Antilles, depth 1600 fathoms (Ehrenberg); +Station 347, depth 2250 fathoms. + + + +Subgenus 2. _Cornutellium_ (vel _Ceratarachnium_), Haeckel, 1881, +Prodromus, p. 430. + +_Definition._--Cephalis very small, rudimentary, hyaline, without distinct +collar septum, and without pores (or with scarce, rudimentary pores). +Thorax smooth. + + +12. _Sethoconus hexagonalis_, Haeckel. + + _Cornutella trochus_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 287, Taf. ix. fig. 14. + +Cephalis very small, subspherical, hyaline, without pores, with a +rudimentary horn of half the length. Thorax slenderly conical, or +bottle-shaped, twice to three times as long as broad; in the lower half +nearly cylindrical, with very thin, thread-like bars, and regular, +hexagonal pores, increasing in size towards the mouth. + +_Dimensions._--Cephalis 0.005 diameter, thorax 0.12 long, 0.05 broad. + +_Habitat._--Indian Ocean, Zanzibar, depth 2200 fathoms (Pullen). + + +13. _Sethoconus verrucosus_, Haeckel. + + _Cornutella verrucosa_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 287, Taf. ix. fig. 16. + +Cephalis very small, subspherical, hyaline, without pores, with a +rudimentary horn of half the {1294}length. Thorax slenderly conical, or +bottle-shaped, with little convex outlines; three to four times as long as +broad, papillate, with regular, circular pores, which are included by +rhombic frames, and increase in size towards the mouth. + +_Dimensions._--Cephalis 0.004 diameter, thorax 0.12 long, 0.035 broad. + +_Habitat._--Indian Ocean (Zanzibar), depth 2200 fathoms (Pullen). + + +14. _Sethoconus orthoceras_, n. sp. (Pl. 54, fig. 11). + + _Cornutella orthoceras_, Haeckel, 1879, Atlas, _loc. cit._ + +Cephalis very small, conical, hyaline, without pores, with a double +internal stricture, and a very short, rudimentary horn. Thorax slenderly +conical, with undulate outlines, three to four times as long as broad, with +subregular, roundish pores, gradually increasing in size towards the mouth. + +_Dimensions._--Cephalis 0.02 long, 0.01 broad; thorax 0.16 long, 0.04 to +0.08 broad. + +_Habitat._--South Atlantic, Station 325, surface. + + +15. _Sethoconus profundus_, Haeckel. + + _Cornutella profunda_, Ehrenberg, 1854, Mikrogeol., Taf. xxxv. B, Nr. B. + iv. fig. 21. + + _Cornutella profunda_, Bailey, 1856, Amer. Jour., vol. xxii. pl. i. fig. + 23. + + _Cornutella profunda_, Haeckel, 1862 Monogr. d. Radiol., p. 284. + +Cephalis very small, spherical, hyaline without pores and internal +stricture, with a very short, rudimentary horn. Thorax slenderly conical +with straight outlines, three to four times as long as broad, with +subregular, circular pores, gradually increasing in size towards the mouth. + +_Dimensions._--Cephalis 0.004 to 0.008 diameter, thorax 0.08 to 0.12 long, +0.03 to 0.04 broad. + +_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Indian, Pacific; at +various depths. + + +16. _Sethoconus trichostylus_, Haeckel. + + _Cornutella trichostyla_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 287, Taf. vi. fig. 2. + +Cephalis very small, conical, hyaline, without pores, with a very long, +bristle-shaped, spirally twisted horn, longer than the whole shell. Thorax +slenderly conical, with straight outlines, and very small, regular, +circular pores of nearly equal size, which are separated by broader bars +and spirally ascending oblique crests (according to the figure). + +_Dimensions._--Cephalis 0.004 long, 0.002 broad; thorax 0.06 long, 0.04 +broad. + +_Habitat._--North Pacific (California), depth 2600 fathoms. + + +17. _Sethoconus longisetus_, Haeckel. + + _Cornutella longiseta_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 287, Taf. ix. fig. 15. + +Cephalis very small, spherical, hyaline, without pores, with a very long, +bristle-shaped horn, {1295}nearly as long as the shell. Thorax slenderly +conical, rough, with straight outlines, and irregular, roundish pores, +gradually increasing in size towards the mouth. + +_Dimensions._--Cephalis 0.01 diameter, thorax 0.09 long, 0.03 broad. + +_Habitat._--Indian Ocean (Zanzibar), depth 2200 fathoms (Pullen). + + +18. _Sethoconus gracilis_, Haeckel. + + _Eucyrtidium gracile_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 70, Taf. xi. fig. 15. + +Cephalis small, subspherical, with few scarce pores, and a stout, pyramidal +horn, of the same length. Thorax slenderly conical, three to four times as +long as broad, with straight outlines, and very small and numerous circular +pores of equal size. + +_Dimensions._--Cephalis 0.015 diameter, thorax 0.12 long, 0.04 broad. + +_Habitat._--Fossil in Barbados. + + +19. _Sethoconus bimarginatus_, n. sp. (Pl. 54, fig. 12). + + _Cornutella bimarginata_, Haeckel, 1879, Atlas, _loc. cit._ + +Cephalis very small, subspherical, hyaline, without pores, with a +rudimentary, conical horn of the same length. Thorax slenderly conical, +three times as long as broad, with undulated, little convex outlines, and +irregular, roundish, double-contoured pores, arranged in nine longitudinal +series, markedly increasing in size towards the mouth. + +_Dimensions._--Cephalis 0.01 diameter, thorax 0.16 long, 0.05 broad. + +_Habitat._--South Pacific, Station 300, depth 1375 fathoms. + + +20. _Sethoconus clathratus_, Haeckel. + + _Cornutella clathrata_, Ehrenberg, 1854, Mikrogeol., Taf. xxii. fig. + 39_a_, _b_, _c_. + +Cephalis very small, subspherical, hyaline, without pores, with a +rudimentary horn of half the length. Thorax slenderly conical, three to +four times as long as broad, smooth, with curved axis and small, regular, +circular pores, nearly equal in size. This common species differs from all +others of the genus by the curvation of the axis of the shell, which is +more or less crescentic, or curved like a cowherd's horn; it may, +therefore, represent a peculiar genus, _Sethodrepanum_. + +_Dimensions._--Cephalis 0.003 to 0.006 diameter, thorax 0.08 to 0.16 long, +0.03 to 0.05 broad. + +_Habitat._--Cosmopolitan; Atlantic, Pacific, many stations; fossil in +Barbados and Sicily. + + + +Subgenus 3. _Phlebarachnium_, Haeckel (et _Cladarachnium_, Haeckel), 1881, +Prodromus, p. 430. + +_Definition._--Cephalis small, with very small pores, and internal collar +septum. Thorax spiny or thorny. + + +{1296}21. _Sethoconus facetus_, n. sp. (Pl. 55, fig. 1). + + _Phlebarachnium facetum_, Haeckel, 1881, Prodromus, p. 430. + +Cephalis small, hemispherical, with distinct collar septum, the same +network as the thorax, and numerous bristle-shaped horns of the same +length. Thorax wide, conical, about as long as broad, with slightly convex +outlines; its network extremity delicate, with very small and numerous, +regular, hexagonal pores, disposed in numerous divergent, longitudinal +series, which are convoluted somewhat spirally around the shell axis. +Surface covered with thin, scattered, bristle-shaped spines, about as long +as the cephalis. + +_Dimensions._--Cephalis 0.02 diameter, thorax 0.2 long, 0.22 broad. + +_Habitat._--Central Pacific, Stations 271 to 274, surface. + + +22. _Sethoconus anthocyrtis_, n. sp. (Pl. 62, fig. 21). + + _Anthocyrtis sethoconus_, Haeckel, 1879, Atlas, _loc. cit._ + +Cephalis small, subspherical, with very small pores and numerous radial, +bristle-shaped spines of the same length. Thorax wide, conical, about as +long as broad, with parabolic outlines, its network very delicate, with +subregular, hexagonal meshes. Surface with scarce, bristle-shaped spines +(not represented in the figure). Mouth with a corona of numerous small, +vertical spines. + +_Dimensions._--Cephalis 0.025 diameter, thorax 0.26 long, 0.24 broad. + +_Habitat._--North Pacific, Station 248, surface. + + +23. _Sethoconus virgultus_, n. sp. + + _Cladarachnium virgultum_, Haeckel, 1881, Prodromus, p. 430. + +Cephalis and thorax nearly of the same form and stricture as in _Sethoconus +facetus_, but larger and wider, with the same delicate, hexagonal network +(Pl. 55, fig. 1); it differs from the latter by the wider, more convex and +campanulate form, but mainly by the armature of the surface, which is +densely covered with thin, arborescent, bristle-shaped spines, irregularly +branched, and four to eight times as large as the cephalis. + +_Dimensions._--Cephalis 0.02 diameter, thorax 0.32 long, 0.4 broad. + +_Habitat._--South Pacific, Station 288, surface. + + +24. _Sethoconus setosus_, n. sp. + + _Phlebarachnium setosum_, Haeckel, 1881, Prodromus, p. 430. + +Cephalis small, subspherical, with distinct collar septum, and the same +network as the thorax, with numerous bristle-shaped horns of the same +length. Thorax slenderly conical, twice as long as broad, with irregular, +polygonal pores of little different sizes, and very thin bars. Surface +covered with perpendicular, simple, bristle-shaped spines, about as long as +the cephalis. + +_Dimensions._--Cephalis 0.02 diameter, thorax 0.12 long, 0.22 broad. + +_Habitat._--Central Pacific, Stations 266 to 272, surface. + + +{1297}25. _Sethoconus venosus_, n. sp. (Pl. 55, fig. 2). + + _Phlebarachnium venosum_, Haeckel, 1881, Prodromus, p. 430, et Atlas, + _loc. cit._ + +Cephalis subspherical, with a stout prismatic horn twice the length, +bearing three denticulate edges. The uppermost part of the thorax is +supported by three diverging, radial beams arising from the deep collar +stricture. Thorax wide, conical, nearly twice as long as broad, with +slightly convex, thorny outlines; its delicate network is composed of very +irregular, polygonal meshes of different sizes, separated by stronger bars, +and of numerous very small polygonal pores separated by very thin bars +inside the former. The central capsule of the figured specimen exhibited in +the upper third of the thorax four large club-shaped lobes, which arose +from a very small sphere enclosed in the cephalis and containing the +nucleus. + +_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.4 long, 0.3 broad. + +_Habitat._--Central Pacific, Station 271, surface. + + + +Genus 573. _Periarachnium_,[190] Haeckel, 1881, Prodromus, p. 430. + +_Definition._--#Sethocorida# (vel Dicyrtida eradiata aperta) with conical +or campanulate, gradually dilated thorax, and widely open mouth. Primary +lattice-shell enveloped by an external arachnoidal mantle. Cephalis with +one or more horns. + +The genus _Periarachnium_ has been derived from those forms of the +preceding _Sethoconus_, in which the conical thorax is covered with simple +spines (_Phlebarachnium_) or branched spines (_Cladarachnium_). By +communication of the branches of these spines a second outer shell is +formed, which, like an arachnoidal mantle, envelops the inner primary +shell. + + +1. _Periarachnium periplectum_, n. sp. (Pl. 55, fig. 11). + +Cephalis hemispherical, separated from the thorax by a sharp collar +stricture, from which arise three internal, diverging beams supporting its +upper third. Thorax campanulate, conical, about as long as broad, with +slightly convex outlines. The delicate lattice-work of the entire shell is +double; the inner composed of subregular, hexagonal meshes; the outer of +larger, irregular, polygonal meshes. The bars of the inner are much thicker +than the thin threads of the outer. Both shells are connected by numerous +bristle-shaped beams. The central capsule of the figured specimen exhibited +in the upper part of the thorax three club-shaped lobes, which arose from a +sphere enclosed in the cephalis and containing the nucleus. + +_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.15 long, 0.12 +broad. + +_Habitat._--Central Pacific, Station 271, surface. + + + +{1298}Genus 574. _Sethocephalus_,[191] Haeckel, 1881, Prodromus, p. 430. + +_Definition._--#Sethocorida# (vel Dicyrtida eradiata aperta) with +discoidal, flatly expanded thorax. Cephalis large, without horn. + +The genus _Sethocephalus_ (formerly proposed under the name +_Platycryphalus_) contains some few and rare Sethocorida, distinguished by +the very large cephalis, the collar opening of which is wide open, not +closed by cortinar beams, and surrounded by a very flat, nearly discoidal +thorax, like the brim of a hat. It is possible that this peculiar genus has +been derived from a Tricyrtid (_Theocalyptra_?) by loss of the original +cephalis, and that the apparent large cephalis is the original thorax. + + +1. _Sethocephalus eucecryphalus_, n. sp. (Pl. 56, fig. 13). + +Cephalis very large, campanulate-conical, with irregular, polygonal pores +and thin bars. Thorax short, scarcely broader than the cephalis, beyond the +sharp collar stricture expanded like the brim of a hat, with few rows of +irregular, polygonal pores. (In the specimen figured the thorax was only +half as broad as in another specimen found afterwards.) + +_Dimensions._--Cephalis 0.12 long, 0.09 broad; thorax 0.02 long, 0.12 +broad. + +_Habitat._--South Pacific, Station 285, surface. + + +2. _Sethocephalus platycryphalus_, n. sp. + + _Platycryphalus sethodiscus_, Haeckel, 1881, Prodromus, p. 430. + +Cephalis large, hemispherical, with irregular square pores and thin bars. +Thorax flatly conical, three to four times as broad as the cephalis, beyond +the collar stricture expanded nearly discoidally, with a delicate network +of small, subregular, hexagonal pores. (Similar in general form to +_Sethophormis aurelia_, Pl. 55, fig. 3, but without any trace of collar +beams or radial ribs.) + +_Dimensions._--Cephalis 0.04 long, 0.08 broad; thorax 0.04 long, 0.3 broad. + +_Habitat._--South Pacific, Station 289, surface. + + + +Genus 575. _Sethocyrtis_,[192] n. gen. + +_Definition._--#Sethocorida# (vel Dicyrtida eradiata aperta) with ovate or +subcylindrical thorax, the mouth of which is constricted, simple, without +prominent hyaline peristome. Cephalis with an apical horn. + +{1299}The genus _Sethocyrtis_ and the three following nearly allied genera +differ from the three preceding genera of Sethocorida in the form of the +thorax, which is not gradually dilated, conical, but cylindrical or ovate, +with more or less constricted mouth. _Sethocyrtis_ may be derived from +_Anthocyrtis_ by loss of the terminal feet. Its mouth is quite simple, +without tubular or annular peristome. + + +1. _Sethocyrtis oxycephalis_, n. sp. (Pl. 62, fig. 9). + +Shell rough, subconical, with slight collar stricture. Length of the two +joints = 4 : 9, breadth = 3 : 8. Cephalis ovate, with a pyramidal horn of +half the length. Thorax campanulate, with regular, circular pores, twice as +broad as those of the cephalis. Mouth constricted, scarcely half as broad +as the thorax. + +_Dimensions._--Cephalis 0.04 long, 0.03 broad; thorax 0.09 long, 0.08 +broad. + +_Habitat._--Central Pacific, Stations 263 to 274, depth 2350 to 3000 +fathoms. + + +2. _Sethocyrtis cancrina_, Haeckel. + + _Eucyrtidium cancrinum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 70, Taf. x. fig. 4. + +Shell smooth, bottle-shaped, with obliterated collar stricture. Length of +the two joints = 4 : 9, breadth = 2 : 7. Cephalis subcylindrical, with a +stout conical horn of the same length, and sometimes a smaller accessory +horn at its base. Thorax ovate, truncate, with regular, circular, +quincuncial pores, twice as broad as those of the cephalis. Mouth little +constricted, flat, nearly as broad as the thorax. + +_Dimensions._--Cephalis 0.04 long, 0.02 broad; thorax 0.09 long, 0.07 +broad. + +_Habitat._--Fossil in Barbados. + + +3. _Sethocyrtis diomedis_, n. sp. + +Shell thorny, pear-shaped, with slight collar stricture. Length of the two +joints = 3 : 16, breadth = 4 : 20. Cephalis hemispherical, with a conical +horn of twice the length. Thorax inflate, ovate, truncate at both poles, +with regular, circular pores, twice as broad as those of the thorax. Mouth +constricted, flat, half as broad as the thorax. + +_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.12 to 0.16 long, +0.16 to 0.2 broad. + +_Habitat._--Central Pacific, Stations 265 to 268, depth 2700 to 2900 +fathoms; also fossil in Barbados. + + +4. _Sethocyrtis menelai_, n. sp. + +Shell spiny, pear-shaped, with sharp collar stricture. Length of the two +joints = 3 : 15, breadth = 4 : 18. Cephalis subspherical, with a large, +cylindro-conical horn, about as long as the whole shell. {1300}Thorax +inflate, subspherical, truncate, with large, irregular, roundish pores, +four to six times as large as those of the cephalis. Mouth constricted, +flat, one-third as broad as the thorax. + +_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.15 long, 0.18 +broad. + +_Habitat._--Fossil in Barbados. + + +5. _Sethocyrtis subacuta_, Haeckel. + + _Eucyrtidium subacutum_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 293, Taf. vii. fig. 18. + +Shell smooth, pear-shaped, with sharp collar stricture. Length of the two +joints = 1 : 4, breadth = 1 : 3. Cephalis subspherical, with small, +irregular pores and a rudimentary horn of half the length. Thorax ovate, +with large, subregular, hexagonal pores and thin bars between them. Mouth +constricted, flat, half as broad as the thorax, without prominent +peristome. + +_Dimensions._--Cephalis 0.02 long, 0.02 broad; thorax 0.08 long, 0.06 +broad. + +_Habitat._--Philippine Sea, depth 3300 fathoms (Ehrenberg). + + +6. _Sethocyrtis pleuracantha_, Haeckel. + + _Eucyrtidium pleuracanthum_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 293, Taf. vii. fig. 21. + +Shell smooth, bottle-shaped, with distinct collar stricture. Length of the +two joints = 2 : 4, breadth = 1 : 3. Cephalis slenderly ovate, with an +excentric pyramidal horn of the same length. Thorax inflate, ovate, with +irregular, roundish pores and thin bars between them. Mouth constricted, +flat, half as broad as the thorax, without prominent peristome. + +_Dimensions._--Cephalis 0.04 long, 0.02 broad; thorax 0.08 long, 0.06 +broad. + +_Habitat._--Tropical Pacific, Stations 200, 225, 266, 274, &c., at various +depths. + + +7. _Sethocyrtis agamemnonis_, n. sp. (Pl. 62, figs. 11, _a_, _b_). + +Shell pear-shaped, rough, with sharp collar stricture. Length of the two +joints = 2 : 10, breadth = 3 : 8. Cephalis subspherical, with very small +pores and a small, pyramidal horn of half the length. Thorax inflate, +ovate; in the uppermost part (beyond the collar stricture) with a ring of +six to nine very large roundish pores, which are twice to four times as +broad as the other irregular, roundish pores. (The shell is seen in fig. 11 +from the apical pole, in fig. 11_a_ with the cephalis, in fig. 11_b_ +without it, exhibiting the four central collar pores of the cortinar +septum.) Mouth truncate, without prominent peristome. + +_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.1 long, 0.08 broad. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +{1301}8. _Sethocyrtis cassis_, Haeckel. + + _Cornutella cassis_, Ehrenberg, 1854, Mikrogeol., Taf. xxii. fig. 38. + + _Cyrtocalpis cassis_, Haeckel, 1862, Monogr. d. Radiol., p. 287. + +Shell pear-shaped, smooth, with obliterated collar stricture. Length of the +two joints = 4 : 13, breadth = 3 : 12. Cephalis ovate, with a conical horn +of half the length. Thorax inflate, ovate, with subregular, circular, +quincuncial pores, twice to three times as broad as the bars. Mouth +constricted, truncate, two-thirds as broad as the thorax, without prominent +peristome. + +_Dimensions._--Cephalis 0.04 long, 0.03 broad; thorax 0.13 long, 0.12 +broad. + +_Habitat._--Fossil in Tertiary rocks of Sicily (Caltanisetta). + + + +Genus 576. _Sethocorys_,[193] Haeckel, 1881, Prodromus, p. 430. + +_Definition._--#Sethocorida# (vel Dicyrtida eradiata aperta) with ovate or +sub-cylindrical thorax, the mouth of which is constricted and prolonged +into a ring-like peristome. Cephalis with an apical horn. + +The genus _Sethocorys_ differs from the preceding _Sethocyrtis_, its +ancestral form, in the form of the constricted mouth, which is prolonged +into a prominent, hyaline, tubular, or annular peristome. + + +1. _Sethocorys achillis_, n. sp. (Pl. 62, fig. 8). + +Shell rough, pear-shaped, with distinct collar stricture. Length of the two +joints = 4 : 8, breadth = 3 : 8. Cephalis ovate, with a stout pyramidal +horn of half the length. Thorax nearly spherical, with regular, circular, +quincuncial pores of the same breadth as the cephalic pores. Mouth +constricted, half as broad as the thorax, with a broad, smooth, striated +peristome. + +_Dimensions._--Cephalis 0.04 long, 0.03 broad; thorax 0.08 long, 0.08 +broad. + +_Habitat._--Cosmopolitan; Mediterranean (Corfu), Atlantic, Indian, Pacific; +many stations, at various depths. + + +2. _Sethocorys patrocli_, n. sp. + +Shell thorny, pear-shaped, with slight collar stricture. Length of the two +joints = 4 : 12, breadth = 3 : 10. Cephalis ovate, with a pyramidal horn of +twice the length. Thorax ovate, truncate at both poles, with regular, +circular pores, twice as broad as the cephalic pores. Mouth constricted, +half as broad as the thorax, with a broad, smooth, prominent peristome. + +_Dimensions._--Cephalis 0.04 long, 0.03 broad; thorax 0.12 long, 0.1 broad. + +_Habitat._--Central Pacific, Stations 263 to 274, depth 2350 to 3000 +fathoms. + + +{1302}3. _Sethocorys armadillo_, Haeckel. + + _Eucyrtidium armadillo_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 70, Taf ix. fig. 10. + +Shell slenderly ovate, smooth, with deep collar stricture. Length of the +two joints = 3 : 10, breadth = 4 : 6. Cephalis ovate, at the apex thorny, +with a conical horn of the same length. Thorax smooth, ovate, truncate, +with small, regular, circular pores, disposed in from twelve to fifteen +transverse rows of the same breadth as the cephalic pores. Mouth +constricted, half as broad as the thorax, with a broad, hyaline, prominent +peristome. + +_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.1 long, 0.06 broad. + +_Habitat._--Fossil in Barbados. + + +4. _Sethocorys odysseus_, n. sp. (Pl. 62, fig. 10). + +Shell ovate, smooth, with obliterated collar stricture. Length of the two +joints = 2 : 9, breadth = 4 : 8. Cephalis hemispherical, with a slender, +conical horn of the same length. Thorax nearly spherical, with regular, +circular pores, of the same breadth as the cephalic pores, quincuncially +disposed. Mouth constricted, only one-third as broad as the thorax, with a +broad, hyaline, prominent peristome. + +_Dimensions._--Cephalis 0.02 long, 0.04 broad; thorax 0.09 long, 0.08 +broad. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +5. _Sethocorys amphora_, Haeckel. + + _Lophophaena amphora_, Stoehr, 1880, Palaeontogr., vol. xxvi. p. 99, Taf. + iii. fig. 11. + +Shell ovate, mouth with distinct collar stricture. Length of the two joints += 1 : 5, breadth = 2 : 4. Cephalis hemispherical, with a short conical horn +of half the length. Thorax ovate, truncate, with small, regular, circular, +quincuncial pores. Mouth constricted, half as broad as the thorax, with a +narrow, prominent, hyaline peristome. + +_Dimensions._--Cephalis 0.015 long, 0.03 broad; thorax 0.07 long, 0.06 +broad. + +_Habitat._--Fossil in Tertiary rocks of Sicily; Grotte (Stoehr). + + +6. _Sethocorys ajacis_, n. sp. + +Shell slenderly ovate, smooth, without external collar stricture, but with +an internal septum. Length of the two joints = 1 : 3, breadth = 1 : 2. +Cephalis conical, with a large pyramidal horn of twice the length, and +sometimes with a smaller accessory horn at its base; its pores scarce, +irregular. Thorax ovate, truncate, hyaline, in the greater part without +pores, in the smaller part {1303}with from two to four transverse rows of +small, circular pores only. Mouth constricted, with a large cylindrical, +tubular, hyaline peristome, half as long as the shell. + +_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.09 long, 0.07 +broad. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + + +Genus 577. _Lophophaena_,[194] Ehrenberg, 1847, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 54. + +_Definition._--#Sethocorida# (vel Dicyrtida eradiata aperta) with ovate or +subcylindrical thorax, the mouth of which is either truncate or +constricted. Cephalis armed with several large horns. + +The genus _Lophophaena_ differs from the nearly allied _Sethocorys_ and +_Dictyocephalus_ only in the armature of the large cephalis, which bears a +group of large horns, often arranged in a corona of radial spines. +Sometimes these spines are connected by anastomosing branches (like +_Arachnocorys_). + + + +Subgenus 1. _Lophophaenula_, Haeckel. + +_Definition._--Horns of the cephalis simple, free, radial spines, neither +branched nor connected. + + +1. _Lophophaena galea_, Ehrenberg. + + _Lophophaena galea orci_, Ehrenberg, 1854, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin p. 245. + + _Lophophaena apiculata_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 78, Taf. viii. fig. 11. + + ? _Cornutella spiniceps_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 68, Taf. ii. fig. 6. + +Shell with slight collar stricture. Length of the two joints = 5 : 4, +breadth = 5 : 6. Cephalis subglobular, with numerous bristle-shaped, radial +spines, about as long as its radius. Thorax about the same size, truncate, +conical, smooth, with wide open mouth. Pores in both joints of equal size, +small, regular, circular. + +_Dimensions._--Cephalis 0.05 long, 0.05 broad; thorax 0.04 long, 0.06 +broad. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms; also fossil +in Barbados. + + +3. _Lophophaena radians_, Ehrenberg. + + _Lophophaena radians_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 78, Taf. viii. fig. 9. + + ? _Lophophaena lynx_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 78, Taf. viii. fig. 13. + +Shell with slight collar stricture. Length of the two joints = 4 : 6, +breadth = 4 : 5. Cephalis subglobular, with numerous, stout, conical, +radial spines, about as long as its diameter. Thorax {1304}of about the +same size, subcylindrical, smooth, truncate, with wide open mouth. Pores in +both joints of equal size, small, regular, circular. + +_Dimensions._--Cephalis 0.04 long, 0.04 broad; thorax 0.06 long, 0.05 +broad. + +_Habitat._--Cosmopolitan; Atlantic, Indian, Pacific; also fossil in +Barbados. + + +3. _Lophophaena liothorax_, n. sp. + +Shell with distinct collar stricture. Length of the two joints = 4 : 10, +breadth = 4 : 8. Cephalis subglobular, with large, circular, +hexagonally-framed pores, and with numerous stout, conical, radial spines, +about as long as its diameter. Thorax twice as long, ovate, smooth, +truncate, with little constricted mouth, and with irregular, roundish +pores, of very different sizes. + +_Dimensions._--Cephalis 0.04 long, 0.04 broad; thorax 0.1 long, 0.08 broad. + +_Habitat._--Central Pacific, Stations 270 to 274, depth 2350 to 2925 +fathoms. + + +4. _Lophophaena echinocephala_, n. sp. + +Shell with deep collar stricture. Length of the two joints = 4 : 8, breadth += 4 : 9. Cephalis subglobular, of the same shape as in the preceding +species. Thorax thorny, inflate, nearly spherical, with a constricted mouth +of half the breadth, and with irregular, roundish, double-contoured pores. + +_Dimensions._--Cephalis 0.04 long, 0.04 broad; thorax 0.08 long, 0.09 +broad. + +_Habitat._--North Pacific, Station 253, depth 3125 fathoms. + + + +Subgenus 2. _Lophophaenoma_, Haeckel. + +_Definition._--Horns of the cephalis connected by anastomosing branches. + + +5. _Lophophaena circumtexta_, Haeckel. + + _Lophophaena radians_, var., Ehrenberg, 1875, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 78, Taf. viii. figs. 7, 8. + +Shell with slight collar stricture. Length of the two joints = 4 : 5, +breadth = 4 : 5. Cephalis subglobular, with numerous conical, radial +spines, about as long as its diameter, and at equal distances from the +surface, connected by anastomosing branches. Thorax nearly cylindrical, +smooth, little dilated towards the truncate, wide open mouth. Pores +subregular, circular. + +_Dimensions._--Cephalis 0.04 long, 0.04 broad; thorax 0.05 long, 0.05 +broad. + +_Habitat._--Central Pacific, Stations 265 to 268, depth 2700 to 2900 +fathoms; also fossil in Barbados. + + + +{1305}Genus 578. _Dictyocephalus_,[195] Ehrenberg, 1860, Monatsber. d. k. +preuss. Akad. d. Wiss. Berlin, p. 830. + +_Definition._--#Sethocorida# (vel Dicyrtida eradiata aperta) with ovate or +subcylindrical thorax, the mouth of which is more or less constricted, +either truncate or with a ring-like peristome. Cephalis rounded, without +horn. + +The genus _Dictyocephalus_ has originated probably from _Sethocorys_ by +reduction and loss of the apical horn. The mouth is more or less +constricted, either simple, truncate (_Dictyocryphalus_), or provided with +a prominent, broad, hyaline, annular peristome (_Dictyoprora_). + + + +Subgenus 1. _Dictyoprora_, Haeckel, 1881, Prodromus, p. 430. + +_Definition._--Mouth of the thorax constricted, with a prominent, ring-like +or tubular, hyaline peristome. + + +1. _Dictyocephalus amphora_, n. sp. (Pl. 62, fig. 4). + +Shell smooth, thick-walled, subovate, with slight collar stricture. Length +of the two joints = 5 : 9, breadth = 6 : 8. Cephalis large, obtusely +conical, with numerous oblique pore-canals. Thorax inflate, with six to +eight transverse rows of roundish pores, increasing in size towards the +base. Mouth constricted, one-third as broad as the thorax, with an internal +diaphragm and a narrow hyaline peristome. + +_Dimensions._--Cephalis 0.05 long, 0.06 broad; thorax 0.09 long, 0.08 +broad. + +_Habitat._--Central Pacific, Stations 265 to 272, depth 2425 to 2925 +fathoms. + + +2. _Dictyocephalus urceolus_, n. sp. + + ? _Eucyrtidium Mongolfieri_, Bury, 1862, Polycystins of Barbados, pl. v. + fig. 2. + +Shell smooth, thick-walled, urceolate, with obliterated collar stricture. +Length of the two joints = 5 : 12, breadth = 4 : 10. Cephalis campanulate, +with numerous oblique pore-canals. Thorax inflate, with five or six +transverse rows of roundish pores of equal size. Mouth constricted, nearly +half as broad as the thorax, with a broad hyaline peristome. + +_Dimensions._--Cephalis 0.05 long, 0.04 broad; thorax 0.12 long, 0.1 broad. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms; also fossil +in Barbados. + + +{1306}3. _Dictyocephalus excellens_, Haeckel. + + _Eucyrtidium excellens_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 70, Taf. x. fig. 2. + +Shell annulate, thick-walled, urceolate, with slight collar stricture. +Length of the two joints = 5 : 10, breadth = 4 : 7. Cephalis large, +ovate-conical, with numerous oblique pore-canals. Thorax ovate, with ten to +twelve transverse rows of regular, roundish pores, which are separated by +prominent annular ribs. Mouth constricted, about half as broad as the +thorax, with a broad hyaline peristome. + +_Dimensions._--Cephalis 0.05 long, 0.04 broad; thorax 0.1 long, 0.07 broad. + +_Habitat._--Fossil in Barbados. + + +4. _Dictyocephalus ocellatus_, Haeckel. + + _Dictyocephalus ocellatus_, Haeckel, 1862, Monogr. d. Radiol., p. 297. + + ? _Eucyrtidium ocellatum_, Ehrenberg, 1861, Monatsber. d. k. preuss. + Akad. d. Wiss. Berlin, p. 299. + +Shell smooth, thick-walled, with deep collar stricture. Length of the two +joints = 3 : 9, breadth = 4 : 7. Cephalis subspherical, with numerous +oblique pore-canals. Thorax inflate, campanulate, hyaline, only with three +or four remote transverse rows of circular, double-contoured pores of equal +size. Mouth constricted, one-third as broad as the thorax, with a narrow +hyaline annular peristome. + +_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.09 long, 0.07 +broad. + +_Habitat._--North Atlantic, Greenland; Faeroee Channel (Gulf Stream), John +Murray. + + +5. _Dictyocephalus crassiceps_, Haeckel. + + _Eucyrtidium crassiceps_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 70, Taf. xi. fig. 4. + +Shell smooth, thick-walled, with sharp collar stricture. Length of the two +joints = 4 : 6, breadth = 3 : 4. Cephalis ovate, in the upper part with +scattered pores, in the lower part with one transverse row of pores. Thorax +hyaline, subcylindrical, only with four or five remote transverse rows of +small, circular pores. Mouth constricted, half as broad as the thorax, with +a short hyaline peristome. + +_Dimensions._--Cephalis 0.04 long, 0.03 broad; thorax 0.06 long, 0.04 +broad. + +_Habitat._--Fossil in Barbados. + + +6. _Dictyocephalus australis_, n. sp. (Pl. 62, fig. 1). + +Shell smooth, thick-walled, with slight collar stricture. Length of the two +joints = 2 : 9, breadth = 3 : 6. Cephalis hemispherical, with few small +pores. Thorax subcylindrical, with large, {1307}roundish, double-contoured +pores, irregularly disposed. Mouth constricted, two-thirds as broad as the +thorax, with a broad, hyaline peristome. + +_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.09 long, 0.06 +broad. + +_Habitat._--East coast of Australia, Station 164, surface. + + +7. _Dictyocephalus mediterraneus_, n. sp. (Pl. 62, fig. 2). + +Shell rough, thin-walled, with slight collar stricture. Length of the two +joints = 3 : 10, breadth = 4 : 8. Cephalis hemispherical, with small, +circular pores. Thorax ovate, truncate, with much larger circular pores of +different sizes and thin bars between them. Mouth little constricted, +two-thirds as broad as the thorax, with a narrow, hyaline peristome. + +_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.1 long, 0.08 broad. + +_Habitat._--Mediterranean, Smyrna (Haeckel), surface. + + +8. _Dictyocephalus papillosus_, Haeckel. + + _Eucyrtidium papillosum_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 293, Taf. vii. fig. 10. + +Shell thin-walled, papillate, with obliterated collar stricture. Length of +the two joints = 2 : 7, breadth = 3 : 5. Cephalis hemispherical, with +small, circular pores. Thorax slenderly ovate, with larger, subregular, +circular pores, separated by oblique series of conical papillae. Mouth with +a broad, hyaline peristome (the "third articulus" of Ehrenberg), separated +by a stricture from the little broader thorax. + +_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.07 long, 0.05 +broad. + +_Habitat._--Western Tropical Pacific (Philippine Sea), depth 3300 fathoms. + + +9. _Dictyocephalus tabulatus_, n. sp. + +Shell thin-walled, papillate, with obliterated collar stricture. Length of +the two joints = 2 : 10, breadth = 3 : 7. Cephalis hemispherical, with +small, circular pores. Thorax slenderly ovate, truncate, with large, +subregular, circular, hexagonally-framed pores. Mouth little constricted, +nearly as broad as the thorax, with a broad, hyaline peristome. + +_Dimensions._--Cephalis 0.02 long, 0.03 broad, thorax 0.1 long, 0.07 broad. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +10. _Dictyocephalus reticulum_, Haeckel. + + _Dictyocephalus reticulum_, Haeckel, 1862, Monogr. d. Radiol., p. 297. + + _Eucyrtidium reticulum_, Ehrenberg, 1861, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, p. 300. + +Shell thin-walled, smooth, with deep collar stricture. Length of the two +joints = 2 : 8, breadth = 3 : 5. Cephalis subspherical, with small, +circular pores. Thorax campanulate, with {1308}transverse rows of +alternating square pores. Mouth little constricted, nearly as long as the +thorax, with a narrow, prominent peristome. + +_Dimensions._--Cephalis 0.02 long, 0.03 broad; thorax 0.08 long, 0.05 +broad. + +_Habitat._--Arctic Ocean, Greenland (Schaffner); Iceland (Krabbe). + + +11. _Dictyocephalus ampulla_, n. sp. + +Shell thin-walled, smooth, with slight collar stricture. Length of the two +joints = 1 : 4, breadth = 1 : 3. Cephalis subspherical, without pores, +hyaline. Thorax inflate, subspherical, with scarce and small, +widely-scattered, circular pores. Mouth constricted, only one-third as +broad as the thorax, with a narrow, prominent peristome. + +_Dimensions._--Cephalis 0.02 long, 0.02 broad; thorax 0.08 long, 0.07 +broad. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + + +Subgenus 2. _Dictyocryphalus_, Haeckel, 1881, Prodromus, p. 430. + +_Definition._--Mouth of the thorax flat or truncate, without prominent +ring-like peristome. + + +12. _Dictyocephalus obtusus_, Ehrenberg. + + _Dictyocephalus obtusus_, Ehrenberg, 1860, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, p. 830. + + _Lophophaena obtusa_, Ehrenberg, 1854, Mikrogeol., Taf. xxii. fig. 40. + + _Cornutella obtusa_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 877. + + _Dictyocephalus obtusus_, Haeckel, 1862, Monogr. d. Radiol., p. 296. + +Shell smooth, thick-walled, with distinct collar stricture. Length of the +two joints = 5 : 6, breadth = 4 : 5. Cephalis ovate, little smaller than +the subcylindrical thorax. Pores subregular, circular, of little different +sizes. Mouth truncate, without ring-like peristome. + +_Dimensions._--Cephalis 0.05 long, 0.04 broad; thorax 0.06 long, 0.05 +broad. + +_Habitat._--Fossil in Tertiary rocks of Sicily (Caltanisetta), Grotte, &c. + + +13. _Dictyocephalus globiceps_, n. sp. (Pl. 62, fig. 7). + +Shell rough, thin-walled, with distinct collar stricture. Length of the two +joints = 6 : 8, breadth = 6 : 7. Cephalis subspherical, large, with +circular, double-contoured pores. Thorax cylindrical, with irregular, +roundish pores, the size of which, like the thickness of the wall, +decreases gradually towards the truncate mouth, which has no ring-like +peristome. + +_Dimensions._--Cephalis 0.06 long, 0.06 broad; thorax 0.08 long, 0.07 +broad. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +{1309}14. _Dictyocephalus cavea_, n. sp. + +Shell rough, thin-walled, with slight collar stricture. Length of the two +joints = 3 : 10, breadth = 5 : 7. Cephalis hemispherical, thorny, with +numerous regular, circular pores. Thorax subcylindrical, with very large, +circular, hexagonally-framed pores (in nine longitudinal alternating rows), +three to five times as broad as the cephalic pores. Mouth truncate, wide +open, without ring-like peristome. + +_Dimensions._--Cephalis 0.06 long, 0.1 broad; thorax 0.2 long, 0.14 broad. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +15. _Dictyocephalus capito_, Ehrenberg. + + _Dictyocephalus capito_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 289, Taf. vii. fig. 24. + +Shell smooth, thin-walled, with sharp collar stricture. Length of the two +joints = 7 : 9, breadth = 6 : 8. Cephalis ovate, with numerous irregular, +roundish, densely-crowded pores. Thorax ovate, with very few +widely-scattered, irregular, roundish pores (broken off in Ehrenberg's +figure). Mouth truncate, little constricted, without ring-like peristome. + +_Dimensions._--Cephalis 0.07 long, 0.06 broad; thorax 0.09 long, 0.08 +broad. + +_Habitat._--Western Tropical Pacific (Philippine Sea) Station 206, depth +2100 fathoms. + + +16. _Dictyocephalus hispidus_, Ehrenberg. + + _Dictyocephalus hispidus_, Ehrenberg, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin; Abhandl. d. k. Akad. d. Wiss. Berlin, 1872, p. 289, Taf. v. + fig. 18. + +Shell rough, thin-walled, with deep collar stricture. Length of the two +joints = 3 : 4, breadth = 3 : 5. Cephalis subspherical, spiny, with the +same irregular, roundish pores as the funnel-shaped or nearly ovate thorax. +Mouth truncate, little narrower than the thorax, without ring-like +peristome. + +_Dimensions._--Cephalis 0.03 long, 0.03 broad; thorax 0.04 long, 0.05 +broad. + +_Habitat._--Tropical Atlantic, Mexican Gulf (Ehrenberg); Station 338, depth +1990 fathoms. + + + +Subfamily 2. SETHOCAPSIDA, Haeckel, 1881, Prodromus, p. 433. + +_Definition._--#Sethocyrtida# with the basal mouth of the shell fenestrated +(vel Dicyrtida eradiata clausa). + + + +{1310}Genus 579. _Sethocapsa_,[196] Haeckel, 1881, Prodromus, p. 433 (sensu +emendato). + +_Definition._--#Sethocapsida# (vel Dicyrtida eradiata clausa) with a free +cephalis bearing an apical horn. + +The genus _Sethocapsa_ and the two following genera represent together the +small subfamily of Sethocapsida, or those Dicyrtida in which the mouth of +the thorax is closed, and no radial apophyses are present. _Sethocapsa_ may +be derived either from _Lithopera_ by loss of the three radial rods, or +from _Sethocyrtis_ by closure of the mouth. + + +1. _Sethocapsa pyriformis_, n. sp. (Pl. 57, fig. 2). + +Shell rough, pear-shaped, with slight collar stricture. Length of the two +joints = 3 : 10, breadth = 3 : 8. Cephalis subspherical, with numerous +small pores, and a short pyramidal or conical horn of half the length. +Thorax ovate, with subregular, circular, quincuncial pores. + +_Dimensions._--Cephalis 0.03 diameter, thorax 0.1 long, 0.08 broad. + +_Habitat._--Central Pacific, Stations 263 to 274, depth 2350 to 3000 +fathoms. + + +2. _Sethocapsa lagena_, Haeckel. + + _Lithopera lagena_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 78, Taf. iii. fig. 4. + +Shell smooth, pear-shaped, with sharp collar stricture. Length of the two +joints = 3 : 8, breadth = 3 : 6. Cephalis pear-shaped, with few scarce +pores, and a small conical horn of half the length. Thorax pear-shaped, +with irregular, roundish pores. This species differs from the similar +_Lithopera lagena_ almost only in the complete absence of the three +internal radial collar beams inside the thorax, and may be derived from it +by their retrograde metamorphosis. + +_Dimensions._--Cephalis 0.03 diameter, thorax 0.08 long, 0.06 broad. + +_Habitat._--Fossil in Barbados. + + +3. _Sethocapsa macroceros_, n. sp. + +Shell smooth, pear-shaped, with slight collar stricture. Length of the two +joints = 2 : 11, breadth = 2 : 9. Cephalis subspherical, with small +circular pores, and a very large, straight, pyramidal horn, of about the +same length as the shell. Thorax ovate, with large, irregular, roundish +pores, which are surrounded by polygonal frames. + +_Dimensions._--Cephalis 0.02 diameter, thorax 0.11 long, 0.09 broad. + +_Habitat._--Central Pacific, Station 270, depth 2925 fathoms. + + +{1311}4. _Sethocapsa nidus_, Haeckel. + + _Lithopera nidus pendulus_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 78, Taf. iii. fig. 7. + +Shell smooth, pear-shaped, with distinct collar stricture. Length of the +two joints = 3 : 6, breadth = 3 : 5. Cephalis subspherical, with a large, +straight, pyramidal horn of twice the length, and scarce small pores. +Thorax ovate, also with very small and scarce pores. + +_Dimensions._--Cephalis 0.03 diameter, thorax 0.06 long, 0.05 broad. + +_Habitat._--Fossil in Barbados. + + +5. _Sethocapsa bulla_, n. sp. + +Shell spiny, with slight collar stricture. Length of the two joints = +3 : 12, breadth = 4 : 12. Cephalis hemispherical, with small, scarce pores, +and a conical horn of the same length. Thorax nearly spherical, with large, +subregular, circular, quincuncial pores, twice as broad as the bars. + +_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.12 long, 0.12 +broad. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms; fossil in +Barbados. + + +6. _Sethocapsa ampulla_, n. sp. + +Shell papillate, with slight collar stricture. Length of the two joints = +1 : 5, breadth = 1 : 5. Cephalis hemispherical, hyaline, without pores, +with a large pyramidal horn of twice the length. Thorax nearly spherical, +with large, irregular, roundish, lobulated pores. + +_Dimensions._--Cephalis 0.03 long, 0.04 broad; thorax 0.15 long, 0.15 +broad. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +7. _Sethocapsa staurocephala_, Haeckel. + + ? _Lithopera oxystauros_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 78, Taf. iii. fig. 6. + + ? _Lithopera amblystauros_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 78, Taf. iii. fig. 5. + +Shell smooth, with slight collar stricture. Length of the two joints = +3 : 4, breadth = 3 : 4. Cephalis large, ovate, with a conical horn of the +same length, small scarce pores, and an internal frontal septum, composed +of two crossed beams, a vertical and a horizontal. Thorax little larger +than the cephalis, ovate, with irregular, small and scarce pores. (The two +figures of Ehrenberg are either incomplete--in _Lithopera amblystauros_, +the cephalic horn, and in _Lithopera oxystauros_, the basal part of the +thorax, being broken off--or they belong to different #Botryodea#). + +_Dimensions._--Cephalis 0.03 diameter, thorax 0.04 diameter. + +_Habitat._--Fossil in Barbados. + + + +{1312}Genus 580. _Dicolocapsa_,[197] Haeckel, 1881, Prodromus, p. 433 +(sensu emendato). + +_Definition._--#Sethocapsida# (vel Dicyrtida eradiata clausa) with a free +cephalis, without apical horn. + +The genus _Dicolocapsa_ differs from the preceding _Sethocapsa_ in the loss +of the apical horn, and therefore bears to it the same relation that +_Dictyocephalus_ does to _Sethocyrtis_. + + +1. _Dicolocapsa microcephala_, n. sp. (Pl. 57, fig. 1). + +Shell smooth, thin-walled, with distinct collar stricture. Cephalis small, +subspherical, with small, crowded pores. Length of the two joints = 1 : 3, +breadth = 1 : 3. Thorax also nearly spherical, three times as large as the +cephalis, with small, irregularly scattered, circular pores, and much +broader bars. + +_Dimensions._--Cephalis 0.03 diameter, thorax 0.09 diameter. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +2. _Dicolocapsa megacephala_, n. sp. + +Shell smooth, thin-walled, with sharp collar stricture. Cephalis large, +conical, obtuse. Length of the two joints = 5 : 9, breadth = 6 : 8. Thorax +ovate, truncate, with hemispherical base. Pores of both joints equal, +subregular, circular, about as broad as the bars. + +_Dimensions._--Cephalis 0.05 long, 0.06 broad; thorax 0.09 long, 0.08 +broad. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +3. _Dicolocapsa platycephala_, n. sp. + +Shell papillate, thick-walled, with slight collar stricture. Cephalis flat, +hemispherical, hyaline, without pores (or with few small pores). Length of +the two joints = 2 : 11, breadth = 4 : 9. Thorax ovate, with small, +regular, circular pores, half as broad as the bars. + +_Dimensions._--Cephalis 0.02 long, 0.04 broad; thorax 0.11 long, 0.09 +broad. + +_Habitat._--Fossil in Barbados. + + + +Genus 581. _Cryptocapsa_,[198] Haeckel, 1881, Prodromus, p. 433. + +_Definition._--#Sethocapsida# (vel Dicyrtida eradiata clausa) with a +cephalis hidden in the thorax, without apical horn. + +{1313}The genus _Cryptocapsa_ differs from the preceding _Dicolocapsa_, its +ancestral form, in the peculiar shape of the cephalis, which is nearly +perfectly enclosed in the upper part of the inflated thorax. It has, +therefore, to the latter the same relation as _Carpocanium_ bears to +_Anthocyrtis_. + + +1. _Cryptocapsa bacca_, n. sp. + +Cephalis spherical, with small circular pores enclosed in the upper part of +the thorax, which is ovate, smooth, and exhibits regular, circular pores, +about as broad as the bars. + +_Dimensions._--Cephalis 0.03 diameter, thorax 0.15 long, 0.12 broad. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +2. _Cryptocapsa pila_, n. sp. + +Cephalis spherical, with few small pores, enclosed in the upper part of the +thorax, which is pear-shaped, spiny, and exhibits subregular, hexagonal +pores, three times as broad as the bars. From each hexagon corner a small +thorn arises. + +_Dimensions._--Cephalis 0.04 diameter, thorax 0.25 long, 0.17 broad. + +_Habitat._--Central Pacific, Station 269, depth 2900 fathoms. + + +---- + + +Section III. TRICYRTIDA, Haeckel, 1881, Prodromus, p. 426, 434. + +_Definition._--#Cyrtoidea# trithalamia, with three-jointed shell, composed +of cephalis, thorax, and abdomen, with two separating transverse +constrictions, an upper collar, and a lower lumbar constriction. + +_Synopsis of the Families and Subfamilies of Tricyrtida._ + + Family LXV. Podocyrtida. { Mouth open, Theopilida. + Three radial apophyses. { + { Mouth closed, Theoperida. + + Family LXVI. Phormocyrtida. { Mouth open, Theophormida. + Numerous radial apophyses. { + { Mouth closed, Theophaenida. + + Family LXVII. Theocyrtida. { Mouth open, Theocorida. + No radial apophyses. { + { Mouth closed, Theocapsida. + + + +{1314}Family LXV. #PODOCYRTIDA#, n. fam. (Pl. 67, 68, 71-73). + + _Theopilida et Theoperida_, Haeckel, 1881, Prodromus, p. 435, 436. + +_Definition._--#Tricyrtida# triradiata. (#Cyrtoidea# with a three-jointed +shell, divided by two transverse constrictions into cephalis, thorax, and +abdomen, and bearing three radial apophyses.) + +The family #Podocyrtida#, composed of the Theopilida and Theoperida of my +Prodromus, comprises those #Cyrtoidea# in which the lattice-shell is +three-jointed and triradial, bearing three external apophyses. The two +subfamilies differ in the shape of the basal mouth, which in the Theopilida +is a simple wide opening, in the Theoperida closed by a lattice-plate. The +latter are derived from the former by development of this closing plate. +The phylogenetic origin of the Podocyrtida may be found in the +Tripocyrtida, from which they are derived by development of an abdomen. But +there are also some forms, which may be derived directly from the +#Plectoidea#, and the origin of some other forms seems to be doubtful. + +The Podocyrtida represent one of the largest groups of #Cyrtoidea#, very +rich in numerous species, which are partly very common and widely +distributed. A large number of living and fossil species has already been +described and figured by Ehrenberg, (1872, 1879, _loc. cit._). These mainly +belong to his genera _Podocyrtis_, _Pterocanium_, _Rhopalocanium_, +_Lithornithium_, &c., and many of them are very characteristic and common +forms, in which the triradial structure of the three-jointed shell is +visible at first view. We distinguish here twenty genera and one hundred +and fifty species. The majority have a shell with a simple wide open mouth +(Theopilida, fourteen genera and one hundred and eighteen species), in the +minority the mouth is closed by lattice-work (Theoperida, six genera and +thirty-two species). + +The three joints of the shell have in the majority of Podocyrtida such a +proportion that the cephalis is the smallest, the abdomen the largest, and +the thorax between them intermediate in size. The cephalis bears almost +constantly an apical horn; this is rarely reduced or lost; sometimes two or +more horns are developed. The three radial apophyses arise originally from +the base of the cephalis, and may from this point run along the shell-wall +embedded in the lattice-plate of the thorax and the abdomen. They leave the +latter at very different points, and form either lateral wings or terminal +feet, sometimes both together. They are either solid or latticed, sometimes +also branched, and of very various shape. Often only the three terminal +feet surrounding the mouth have remained, whilst the ribs have disappeared. + +Many species of this large family are very variable and connected with +other different species by numerous transitional forms; the distinction of +the genera described is also often very difficult. + +{1315}_Synopsis of the Genera of Podocyrtida._ + + ------------------------------------------------------------------------- + I. Subfamily Theopilida. (Podocyrtida aperta.) + Terminal mouth of the shell a simple wide opening. + -------------------- + A. Three free limbs or wings on the thorax (partly also on the abdomen). + ------------------------------------------------------------------------- + { { Wings arising from + { { the thorax, 582. _Pterocorys_. + { { + { Three wings of { Three ribs enclosed + { the thorax { in the wall of the + { solid. { thorax, 583. _Theopilium_. + No free { { + external { { Wings arising free + appendages{ { from the collar + on the { { stricture, 584. _Corocalyptra_. + abdomen. { + { { Wings not prolonged + { Three wings of { into the cephalis, 585. _Dictyoceras_. + { the thorax { + { latticed. { Wings prolonged + { { into the cephalis, 586. _Pteropilium_. + + { Three ribs { Ribs and feet + { prolonged { solid, 587. _Theopodium_. + { into three { + { terminal { Ribs and feet + Free { feet. { latticed, 588. _Pterocanium_. + appendages{ + on the { Three free { Wings and feet + abdomen. { wings on the { solid, 589. _Pterocodon_. + { thorax. { + { Numerous { Wings and feet + { terminal feet. { latticed, 590. _Dictyocodon_. + + ------------------------------------------------------------------------- + B. Free appendages not on the thorax, only on the abdomen. + ------------------------------------------------------------------------- + Abdomen with three ribs and three feet, 591. _Pleuropodium_. + + { Three feet solid, + { simple, 592. _Podocyrtis_. + Abdomen without lateral { + ribs, with three { Three feet solid, + terminal feet. { ramified, 593. _Thyrsocyrtis_. + { + { Three feet latticed, 594. _Dictyopodium_. + ------------------------------------------------------------------------- + II. Subfamily Theoperida. (Podocyrtida clausa.) + Terminal mouth of the shell closed by a lattice-plate. + -------------------- + Three lateral wings only on the thorax, + ------------------------------------------------------------------------- + Wings solid, 595. _Lithornithium_. + + Wings latticed, 596. _Sethornithium_. + ------------------------------------------------------------------------- + Three lateral wings beginning from the thorax and prolonged + into the abdomen, + ------------------------------------------------------------------------- + 597. _Theopera_. + ------------------------------------------------------------------------- + Three wings only on the abdomen. + ------------------------------------------------------------------------- + { No horn on the + { basal pole, 598. _Rhopalocanium_. + Spell spindle-shaped, with { + three lateral wings on the { Basal pole of the + abdomen. { shell with a horn, 599. _Rhopalatractus_. + + Shell three-sided pyramidal, with three + terminal-feet on the basal corners, 600. _Lithochytris_. + + + +Subfamily 1. THEOPILIDA, Haeckel, Prodromus, p. 435. + +_Definition._--#Podocyrtida# with the terminal mouth of the shell open (vel +Tricyrtida triradiata aperta). + + + +{1316}Genus 582. _Pterocorys_,[199] Haeckel, 1881, Prodromus, p. 435. + +_Definition._--#Theopilida# (vel Tricyrtida triradiata aperta) with three +simple, free lateral wings arising from the sides of the thorax. + +The genus _Pterocorys_, comprising numerous and some very common species, +may be one of the oldest and most primitive Theopilida, and is perhaps the +common ancestral form of all Tricyrtida. It exhibits three free lateral +wings, arising from the sides of the thorax, like _Lithomelissa_ among the +Dicyrtida, and may be derived directly from this genus by development of an +abdomen. The latter is commonly cylindrical or ovate, with a wide open +mouth, whilst the thorax is either campanulate or three-sided and +pyramidal. + + + +Subgenus 1. _Pterocyrtidium_, Buetschli, 1882, Zeitschr. f. wiss. Zool., +vol. xxxvi. p. 531. + +_Definition._--Horn of the cephalis simple. Abdomen not prolonged into a +narrow tube. + + +1. _Pterocorys campanula_, n. sp. (Pl. 71, fig. 3). + +Shell campanulate, with two distinct strictures. Length of the three joints += 2 : 3 : 2, breadth = 2 : 4 : 6. Cephalis subovate, with a pyramidal horn +of the same length. Thorax subconical, in the middle zone with three +conical, horizontal wings, shorter than the cephalis, from which three thin +ribs are decurrent to the mouth. Abdomen short and much dilated, with wide, +truncate mouth. Pores nearly equal, small, subregular, circular. + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.06, _c_ 0.04; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.12. + +_Habitat._--Central Pacific, Stations 266 to 274, surface. + + +2. _Pterocorys carinata_, Haeckel. + + _Eucyrtidium carinatum_, Haeckel, 1862, Monogr. d. Radiol., p. 322, Taf. + vii. figs. 4-7. + +Shell subovate, with two distinct strictures. Length of the three joints = +1 : 2 : 3, breadth = 1 : 3 : 4. Cephalis ovate, with a pyramidal horn of +twice the length. Thorax campanulate, with three decurrent crests, from +which in the lower part three small conical wings arise, shorter than the +cephalis. Abdomen barrel-shaped, inflated, with wide, truncate mouth. Pores +everywhere equal, small, regular, circular, quincuncial. + +_Dimensions._--Length of the three joints, _a_ 0.25, _b_ 0.05, _c_ 0.075; +breadth, _a_ 0.25, _b_ 0.09, _c_ 0.1. + +_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Pacific; many stations, +surface. + + +{1317}3. _Pterocorys sabae_, Haeckel. + + _Pterocanium sabae_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 299, Taf. x. fig. 17. + +Shell campanulate or subconical, with two sharp strictures. Length of the +three joints = 1 : 3 : 4, breadth = 1 : 4 : 5. Cephalis subspherical, with +a conical horn of the same length. Thorax subconical, in the lower third +with three small, conical, little curved wings, shorter than the cephalis. +Abdomen dilated towards the wide, truncate mouth. Pores subregular, +circular, gradually increasing in size from the collar towards the mouth. + +_Dimensions._--Length of the three joints, _a_ 0.025, _b_ 0.06, _c_ 0.08; +breadth, _a_ 0.02, _b_ 0.08, _c_ 0.09. + +_Habitat._--Indian Ocean, Zanzibar, 2200 fathoms (Pullen). + + +4. _Pterocorys columba_, n. sp. (Pl. 71, fig. 2). + +Shell subovate, with two deep strictures. Length of the three joints = +2 : 5 : 4, breadth = 3 : 7 : 7. Cephalis hemispherical, with a curved +conical horn of the same length. Thorax inflate, in the middle zone with +three pyramidal downwardly divergent wings of nearly the same length. +Abdomen short, inflate, little constricted towards the wide, truncate +mouth. Pores all nearly equal, subregular, circular. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.05, _c_ 0.04; +breadth, _a_ 0.03, _b_ 0.07, _c_ 0.07. + +_Habitat._--North Pacific, Station 237, surface. + + +5. _Pterocorys falcifera_, Haeckel. + + _Pterocanium falciferum_, Stoehr, 1880, Palaeontogr., vol. xxvi. p. 107, + Taf. iv. fig. 15. + + ? _Pterocanium bibrachiatum_, Stoehr, 1880, Palaeontogr., vol xxvi. p. + 106, Taf. iv. fig. 14. + +Shell subovate, with two distinct strictures. Length of the three joints = +2 : 6 : 5, breadth = 3 : 9 : 10. Cephalis subspherical, with a conical horn +of the same length. Thorax hemispherical, thick-walled, rough, with three +stout triangular wings, which are about as long as the shell, and curved +downwards, with upper convexity. Abdomen ovate, cylindrical, with wide, +truncate mouth. Pores irregular, roundish, large and small intermingled; at +the base of the abdomen (below the lumbar girdle) a circle of somewhat +oblong, quadrangular pores. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.05; +breadth, _a_ 0.03, _b_ 0.09, _c_ 0.1. + +_Habitat._--Fossil in Tertiary rocks of Sicily, Grotte (Stoehr); +Caltanisetta (Haeckel). + + +6. _Pterocorys aquila_, n. sp. (Pl. 71, fig. 5). + +Shell ovate, with two deep strictures. Length of the three joints = +1 : 4 : 4, breadth = 1 : 8 : 6. Cephalis hemispherical, with a slender +curved horn of three times the length. Thorax hemispherical, campanulate, +spiny, prolonged above the lumbar girdle into three stout, three-sided +prismatic {1318}wings, which are longer than the shell, fenestrated at the +base, and S-shaped, curved. Abdomen barrel-shaped, with wide, truncate +mouth. Pores irregular, roundish, of very different sizes. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.08, _c_ 0.08; +breadth, _a_ 0.03, _b_ 0.16, _c_ 0.12. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +7. _Pterocorys hirundo_, n. sp. (Pl. 71, fig. 4). + +Shell slender, ovate, with two deep strictures. Length of the three joints += 1 : 4 : 4, breadth = 2 : 5 : 5. Cephalis hemispherical, with a large +pyramidal horn longer than the half shell. Thorax conical, spiny, prolonged +above the lumbar girdle into three slender, triangular, prismatic wings, +which are about as long as the shell, and slightly curved downwards, with +lower convexity. Abdomen inflated, with wide, truncate mouth. Pores +irregular, roundish, of very different sizes. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.08, _c_ 0.08; +breadth, _a_ 0.04, _b_ 0.1, _c_ 0.1. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +8. _Pterocorys barbadensis_, Haeckel. + + _Pterocanium barbadense_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 82, Taf. xvii. fig. 6. + + _Pterocyrtidium barbadense_, Buetschli, 1882, Zeitschr. f. wiss. Zool., + Bd. xxxvi., Taf. xxxiii. fig. 29, _a_, _b_. + +Shell slender, smooth, with two slight strictures. Length of the three +joints = 1 : 3 : 4, breadth = 2 : 4 : 4. Cephalis hemispherical, with a +stout pyramidal horn of twice the length. Thorax campanulate-conical, in +the lower half with three divergent, angular wings, which are slightly +curved downwards, and as long as the thorax. Abdomen cylindrical, with +wide, truncate mouth. Pores small, subregular, circular. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.05, _c_ 0.07; +breadth, _a_ 0.04, _b_ 0.07, _c_ 0.07. + +_Habitat._--Fossil in Barbados. + + +9. _Pterocorys apis_, Haeckel. + + _Pterocodon apis_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, + p. 82, Taf. xix. fig. 3. + +Shell slender, smooth, with two distinct strictures. Length of the three +joints = 1 : 2 : 6, breadth = 2 : 3 : 4. Cephalis hemispherical, with a +curved, conical horn of three times the length. Thorax very small, with +three nearly horizontal, conical wings, which are slightly curved +downwards, and twice as long as the thorax. Abdomen cylindrical, three +times as long as the thorax, with wide, truncate mouth. Pores small, +subregular, circular. Differs from all other species in the very small size +of the thorax; the abdomen is broken off in Ehrenberg's figure. + +_Dimensions._--Length of the three joints, _a_ 0.15, _b_ 0.02, _c_ 0.06; +breadth, _a_ 0.02, _b_ 0.03, _c_ 0.04. + +_Habitat._--Cosmopolitan; Atlantic, Pacific, many stations; also fossil in +Barbados. + + +{1319}10. _Pterocorys melitta_, Haeckel. + + _Rhopalocanium ornatum_, Bury, 1862, Polycystins of Barbados, Taf. vi. + fig. 4. + +Shell slender, smooth, with two deep strictures. Length of the three joints += 1 : 1 : 3, breadth = 1 : 2 : 2. Cephalis subspherical, with a pyramidal +horn of twice the length. Thorax broad and short, loaf-shaped, with three +conical wings, which are horizontally expanded, and half as long as the +shell. Abdomen cylindrical, with wide, truncate mouth. Pores small, +subregular, circular. + +_Dimensions._--Length of the three joints, _a_ 0.025, _b_ 0.03, _c_ 0.09; +breadth, _a_ 0.03, _b_ 0.06, _c_ 0.06. + +_Habitat._--Fossil in Barbados. + + +11. _Pterocorys turgida_, Haeckel. + + _Lychnocanium turgidum_, Ehrenberg, 1885, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 80, Taf. vii. fig. 6. + +Shell thick-walled, pear-shaped, smooth, with sharp collar stricture. The +lumbar stricture is not distinct externally, but is represented by a broad, +internal, annular septum. Length of the three joints = 1 : 6 : 3, breadth = +2 : 7 : 6. Cephalis hemispherical, with a stout pyramidal horn of the same +length. Thorax and abdomen together pear-shaped, inflated. Immediately +above the lumbar stricture three stout, conical, lateral wings, as long as +the cephalis, arise. Mouth very small, about as broad as the cephalis. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.12, _c_ 0.06; +breadth, _a_ 0.03, _b_ 0.13, _c_ 0.12. + +_Habitat._--Fossil in Barbados. + + + +Subgenus 2. _Pterosyringium_, Haeckel. + +_Definition._--Horn of the cephalis simple. Abdomen prolonged into a narrow +cylindrical tube. + + +12. _Pterocorys tubulosa_, n. sp. (Pl. 68, fig. 6). + + _Pterosyringium tubulosum_, Haeckel, 1879, Atlas, _loc. cit._ + +Shell thick-walled, rough, with two slight strictures. Length of the three +joints = 1 : 4 : 4, breadth = 1 : 3 : 1. Cephalis hemispherical, with a +conical horn of the same length. Thorax ovate, in the upper half with three +ribs, arising into short, triangular, slightly prominent wings. Abdomen +prolonged into a cylindrical, narrow tube of the same length as the thorax. +Terminal mouth very narrow. Pores subregular, circular. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.12, _c_ 0.12; +breadth, _a_ 0.03, _b_ 0.09, _c_ 0.03. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +{1320}13. _Pterocorys pipetta_, n. sp. + +Shell thin-walled, smooth, with two slight strictures. Length of the three +joints = 1 : 6 : 3, breadth = 1 : 3 : 1. Cephalis ovate, with a conical +horn of twice the length. Thorax ovate, in the middle zone with three +conical wings of the same length, curved slightly downwards (like those of +_Pterocorys columba_, Pl. 71, fig. 2). Abdomen constricted into a +cylindrical tube half as long as the thorax, with narrow mouth. Pores +subregular, circular. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.12, _c_ 0.06; +breadth, _a_ 0.02, _b_ 0.06, _c_ 0.02. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + + +Subgenus 3. _Pterocorythium_, Haeckel. + +_Definition._--Horn of the cephalis double or multiple. Abdomen not +prolonged into a narrow tube. + + +14. _Pterocorys rhinoceros_, n. sp. (Pl. 71, fig. 1). + +Shell very delicate and thin-walled, with two sharp strictures. Length of +the three joints = 2 : 10 : 3, breadth, 3 : 11 : 9. Cephalis obtuse, +conical, with two divergent, conical horns of equal length. Thorax +triangular, pyramidal; from its three edges there arise on the middle joint +three conical descending wings (little larger than the horns), and from the +base of each wing descend two divergent crests, forming at the sides of the +pyramid three rounded lobes. Abdomen short, cylindrical, with wide, +truncate mouth. Network of the whole shell very delicate, with very small +and numerous, regular, circular, hexagonally-framed pores. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.1, _c_ 0.03; +breadth, _a_ 0.03, _b_ 0.11, _c_ 0.09. + +_Habitat._--Central Pacific, Stations 270 to 274, surface, and in various +depths. + + +15. _Pterocorys prismatica_, n. sp. + +Shell very delicate and thin-walled throughout, with fine fenestration +similar to that of the preceding species, but differing from it in the form +of the abdomen, which is much larger, three-sided and prismatic; three +edges of the prism decurrent from the bases of the three short wings. +Length of the three joints = 1 : 4 : 5, breadth = 2 : 6 : 6. No lobes at +the thorax. Mouth wide open, truncate, triangular. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.08, _c_ 0.1; +breadth, _a_ 0.04, _b_ 0.12, _c_ 0.12. + +_Habitat._--South Pacific, Station 288, surface. + + +16. _Pterocorys tricornis_, n. sp. + +Shell spiny, with two deep strictures. Length of the three joints = +1 : 5 : 3, breadth = 1 : 7 : 5. Cephalis subspherical, with three stout, +pyramidal, divergent horns, which are three times as long, {1321}and bear +three serrated edges. Thorax three-sided pyramidal, spiny; its three edges +prolonged at the girdle into three stout, triangular, prismatic wings of +the same length, little curved. Abdomen short, cylindrical, with wide open, +truncate mouth. Pores irregular, polygonal, roundish. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.1, _c_ 0.06; +breadth, _a_ 0.03, _b_ 0.14, _c_ 0.1. + +_Habitat._--North Pacific, Station 244, surface. + + +17. _Pterocorys zittelii_, Haeckel. + + _Pterocyrtidium zittelii_, Buetschli, 1882, Zeitschr. f. wiss. Zool., + vol. xxxvi. pp. 531, 540, Taf. xxxiii. figs. 28, _a_, _b_. + +Shell thin-walled, rough, with two slight strictures. Length of the three +joints = 2 : 5 : 7, breadth = 3 : 5 : 5. Cephalis hemispherical, armed with +a very large, prismatic, vertical horn, which is half as long as the shell, +and at its base surrounded by several (three to five) shorter, upwardly +diverging horns. Thorax campanulate, in the upper half with three short, +downwardly diverging, conical wings. Abdomen subcylindrical, with wide, +truncate mouth. Pores small, subregular, circular. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.05, _c_ 0.07; +breadth, _a_ 0.03, _b_ 0.05, _c_ 0.05. + +_Habitat._--Fossil in Barbados. + + +18. _Pterocorys macroptera_, n. sp. + +Shell thin-walled, smooth, with two slight strictures. Length of the three +joints = 1 : 3 : 2, breadth = 1 : 4 : 3. Cephalis hemispherical, armed with +two larger and six to eight smaller, conical, divergent horns of different +lengths. Thorax three-sided pyramidal; its three edges prolonged into three +very large diverging wings, which are slender, three-sided, prismatic, and +nearly twice as long as the shell. Abdomen short, cylindrical, with wide, +truncate mouth. Pores irregular, roundish, in the middle part of the shell +(on both sides of the girdle) much larger than in the upper and lower part. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.09, _c_ 0.06; +breadth, _a_ 0.04, _b_ 0.12. _c_ 0.1. + +_Habitat._--South Atlantic, Station 335, surface. + + + +Genus 583. _Theopilium_,[200] Haeckel, 1881, Prodromus, p. 435. + +_Definition._--#Theopilida# (vel Tricyrtida triradiata aperta) with three +lateral ribs enclosed in the wall of the thorax, without free lateral or +terminal appendages. + +The genus _Theopilium_ differs from all the other Theopilida in the absence +of free external appendages; it has neither lateral wings nor terminal +feet, but three divergent ribs are enclosed in the wall of the thorax. It +agrees in this character with the Dicyrtid _Lamprodiscus_, and may be +derived directly from this by development of an abdomen. + + +{1322}1. _Theopilium tricostatum_, n. sp. (Pl. 70, fig. 6). + +Shell flatly conical, smooth. Length of the three joints = 1 : 4 : 2, +breadth = 2 : 6 : 10. Cephalis subspherical, with a thin oblique horn of +the same length. Thorax with three stout ribs in its wall, and with +subregular, hexagonal pores increasing in size towards the girdle. Abdomen +flatter than the thorax, without ribs, nearly horizontal, with subregular, +square pores, disposed in four to six concentric, subcircular series of +different sizes; decreasing in size towards the wide open mouth. Seen from +the side, this species resembles _Corocalyptra agnesae_, (Pl. 59, fig. 3). + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.08, _c_ 0.04; +breadth, _a_ 0.03, _b_ 0.12, _c_ 0.2. + +_Habitat._--Central Pacific, Stations 260 to 274, surface. + + +2. _Theopilium triradiatum_, n. sp. + +Shell flatly conical, smooth, in general of the same form as, and with +similar fenestration to, the preceding species, but different in the +proportions. Length of the three joints = 1 : 4 : 2, breadth = 2 : 4 : 6. +Cephalis hemispherical, with two divergent, thin horns of the same length. +Thorax more elevated, about as high as broad. The three divergent ribs are +not limited to the thorax, but prolonged through the whole abdomen, the +outline of which is a prolongation of that of the thorax. + +_Dimensions._--Length of the three joints, _a_ 0.025, _b_ 0.1, _c_ 0.05; +breadth, _a_ 0.05, _b_ 0.1, _c_ 0.15. + +_Habitat._--Tropical Atlantic, Station 347, surface. + + +3. _Theopilium cranoides_, Haeckel. + + _Eucyrtidium cranoides_, Haeckel, 1862, Monogr. d. Radiol., p. 320, Taf. + vii. figs. 1-3. + +Shell campanulate-conical, smooth. Length of the three joints = 2 : 5 : 4, +breadth = 3 : 9 : 10. Cephalis ovate, with a straight, excentric, prismatic +horn of the same length. The campanulate thorax is separated from it by no +external collar stricture, but by an internal septum. From the base of the +horn arise three divergent radial ribs, running in the wall of the two +first joints to the lumbar stricture (_loc. cit._, Taf. vii. fig. 3). +Abdomen short and wide, without ribs. Pores rather large, regular, +circular, quincuncial, in the cephalis smaller. Central capsule four-lobed. + +_Dimensions._--Length of the three joints, _a_ 0.027, _b_ 0.054, _c_ 0.047; +breadth, _a_ 0.03, _b_ 0.09, _c_ 0.1. + +_Habitat._--Mediterranean (Messina), surface. + + + +Genus 584. _Corocalyptra_,[201] n. gen. + +_Definition._--#Theopilida# (vel Tricyrtida triradiata aperta) with three +simple, free, lateral wings, arising from the collar stricture between +cephalis and thorax. + +The genus _Corocalyptra_ comprises a small number of very elegant +hat-shaped Tricyrtida, which resemble greatly _Eucecryphalus_ among the +Dicyrtida. As in the {1323}latter, three free, radial spines, or simple +wings, corresponding to the three basal feet of _Cortina_, arise from the +collar stricture between the small hemispherical cephalis and the large, +flatly conical thorax. _Corocalyptra_ differs from _Eucecryphalus_, its +ancestral form, in the development of a flat and broad abdomen, which is a +prolongation of the thorax, and may be compared to the brim of a hat. + + +1. _Corocalyptra agnesae_, n. sp. (Pl. 59, fig. 3). + +Shell flatly conical or hat-shaped. Length of the three joints = 1 : 4 : 2, +breadth = 2 : 8 : 12. Cephalis hemispherical, with an oblique, small, +conical horn of the same length. From the slight collar stricture arise +three slender, conical feet of equal length, twice as long as the apical +horn, nearly horizontally divergent. Lateral outline of the conical thorax +straight, of the flatter abdomen convex; the smooth margin of the abdomen +turned inwards. Network delicate, with subregular, hexagonal pores. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.08, _c_ 0.04; +breadth, _a_ 0.03, _b_ 0.15, _c_ 0.24. + +_Habitat._--Central Pacific, Station 270, surface. + + +2. _Corocalyptra elisabethae_, n. sp. (Pl. 59, fig. 10). + +Shell flatly conical, hat-shaped, very similar to the preceding species, +but with different proportions. Length of the three joints = 1 : 4 : 2; +breadth = 1 : 7 : 10. Cephalis very small, with an oblique horn of the same +length. The three feet are of different sizes, the caudal odd foot being +twice as long as the two lateral, which are equal to the horn. Lateral +outline of the campanulate thorax convex, of the flatter abdomen less +convex. Margin of the mouth flat. + +_Dimensions._--Length of the three joints, _a_ 0.015, _b_ 0.06, _c_ 0.03; +breadth _a_ 0.02, _b_ 0.14, _c_ 0.2. + +_Habitat._--Tropical Atlantic, Station 347, surface. + + +3. _Corocalyptra emmae_, n. sp. (Pl. 59, fig. 4). + +Shell nearly conical, hat-shaped. Length of the three joints = 1 : 3 : 1, +breadth = 1 : 5 : 7. Cephalis hemispherical, with a straight horn of the +same length. Feet of the collar larger than in the preceding species, the +two lateral smaller being directed upwards, the larger odd caudal +downwards. Thorax slightly campanulate; its hexagonal meshes two to four +times as large as those of the short, convex abdomen, which is turned +inwards. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.09, _c_ 0.03; +breadth, _a_ 0.025, _b_ 0.13, _c_ 0.17. + +_Habitat._--Central Pacific, Station 273, surface. + + +4. _Corocalyptra margarethae_, n. sp. + +Shell nearly conical, hat-shaped, very similar to the preceding species, +but with much more delicate hexagonal network, with thread-like bars. +Length of the three joints = 1 : 7 : 2, breadth = {1324}1 : 10 : 12. +Cephalis hemispherical, with six bristle-shaped spines of half the length +of the shell; three horns divergent upwards, and three alternating feet +divergent downwards. Thorax nearly conical. Abdomen flatter. + +_Dimensions._--Length of the three joints, _a_ 0.015, _b_ 0.1, _c_ 0.03; +breadth, _a_ 0.02, _b_ 0.15, _c_ 0.18. + +_Habitat._--North Pacific, Station 236, surface. + + +5. _Corocalyptra ludovicae_, n. sp. + +Shell flatly campanulate or hat-shaped. Length of the three joints = +1 : 4 : 3, breadth = 2 : 7 : 10. Cephalis hemispherical, with six +bristle-shaped spines, about one-fourth to one-third as long as the shell; +three horns diverging upwards, and three alternate feet diverging +downwards. Thorax nearly conical. Abdomen much larger than in all preceding +species, inflated, with convex, lateral outline; its mouth-edge curved +inwards. The network is much finer than in the similar _Corocalyptra emmae_ +(Pl. 59, fig. 4), and the abdomen is relatively twice as long and broad. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.08, _c_ 0.06; +breadth, _a_ 0.04, _b_ 0.14, _c_ 0.2. + +_Habitat._--Central Pacific, Station 271, surface. + + + +Genus 585. _Dictyoceras_,[202] Haeckel, 1862, Monogr. d. Radiol., p. 333. + +_Definition._--#Theopilida# (vel Tricyrtida triradiata aperta) with three +latticed free lateral wings on the sides of the thorax, which are not +prolonged into the cephalis. + +The genus _Dictyoceras_ and the following _Pteropilium_ agree with the two +preceding genera in the possession of three lateral wings on the sides of +the thorax; but whilst these in the latter are simple solid spines, they +are in the former vertical fenestrated plates. _Dictyoceras_ may be derived +from _Pterocorys_ by development of a vertical lattice-plate between the +thorax and the three free lateral spines arising from it. + + +1. _Dictyoceras insectum_, n. sp. (Pl. 71, figs. 6, 7). + +Shell with two distinct strictures. Length of the three joints = 1 : 3 : 2, +breadth = 2 : 4 : 3. Cephalis hemispherical, with a slender pyramidal horn +of twice the length. Thorax subspherical, in the upper half with three +divergent lattice-wings of the same length, each of which represents a +slender, fenestrated, three-sided pyramid. Abdomen subovate, with wide, +truncate mouth (in the figured specimen broken off). Pores circular, +small, of different sizes. + +_Dimensions._--Length of the three joints, _a_ 0.025, _b_ 0.055, _c_ 0.04; +breadth, _a_ 0.035, _b_ 0.08, _c_ 0.06. + +_Habitat._--Central Pacific, Stations 263 to 274, depth 2350 to 2925 +fathoms. + + +{1325}2. _Dictyoceras formica_, n. sp. (Pl. 71, fig. 8). + +Shell with obliterate collar, but deep lumbar stricture. Length of the +three joints = 1 : 2 : 3, breadth = 2 : 5 : 4. Cephalis conical, with an +oblique curved horn of the same length. Thorax with three vaulted swellings +between the three prominent, diverging lattice-wings, the apex of which is +prolonged downwards into a solid curved spine, half as long as the inflated +abdomen. Mouth little constricted. Pores irregular, roundish, of different +sizes. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.06; +breadth, _a_ 0.03, _b_ 0.1, _c_ 0.09. + +_Habitat._--North Atlantic, Station 353, surface. + + +3. _Dictyoceras melitta_, n. sp. (Pl. 71, fig. 9). + +Shell with two deep strictures. Length of the three joints = 1 : 3 : 4, +breadth = 1 : 6 : 5. Cephalis subspherical, with two conical divergent +horns of the same length. Thorax three-sided pyramidal, the three edges +prolonged into three lattice-wings of the same form, with short, terminal +spines. Abdomen inflated, subovate, with constricted mouth. Pores small, +regular, circular, of equal size, with very thin bars. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.09, _c_ 0.12; +breadth, _a_ 0.04, _b_ 0.18, _c_ 0.15. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms. + + +4. _Dictyoceras bombus_, n. sp. (Pl. 71, fig. 10). + +Shell with deep collar, but evanescent lumbar stricture. Length of the +three joints = 1 : 5 : 3, breadth = 1 : 6 : 7. Cephalis subspherical, with +a conical horn of the same length. Thorax campanulate, with three short and +broad, triangular lattice-wings, the upper edge of which is nearly +horizontal, the lower nearly vertical and decurrent from the height of the +collar to the lumbar stricture. Abdomen inflated, with constricted mouth of +half the breadth. Pores small, subregular, circular, of nearly equal size. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.1, _c_ 0.06; +breadth, _a_ 0.025, _b_ 0.12, _c_ 0.14. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +5. _Dictyoceras virchowii_, Haeckel. + + _Dictyoceras virchowii_, Haeckel, 1862, Monogr. d. Radiol., p. 333, Taf. + viii. figs. 1-5. + + _Lithornithium dictyoceras_, Haeckel, 1860, Monatsber. d. k. preuss. + Akad. d. Wiss. Berlin, 1860, p. 840. + +Shell with two distinct strictures. Length of the three joints = 1 : 3 : 4, +breadth = 1 : 5 : 6. Cephalis subspherical, with an oblique curved horn of +the same length. Thorax conical, with three broad, triangular lattice-wings +different in size and direction, two of which are directed outwards, the +third downwards--each terminated by a strong spine. Abdomen oblique, +inflated, with wide open, truncate mouth. On the shell surface some few +conical spines are scattered. Pores irregular, {1326}roundish, of different +sizes. On the peculiar symmetry of this remarkable form, compare the +detailed description in my Monograph. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.08; +breadth, _a_ 0.02, _b_ 0.1, _c_ 0.12. + +_Habitat._--Mediterranean, Messina, surface. + + + +Genus 586. _Pteropilium_,[203] Haeckel, 1881, Prodromus, p. 435. + +_Definition._--#Theopilida# (vel Tricyrtida triradiata aperta) with three +latticed free lateral wings on the sides of the thorax, prolonged into the +horn of the cephalis in the form of three vertical, free cephalic wings. + +The genus _Pteropilium_ differs from the preceding closely allied +_Dictyoceras_ in the development of three free, vertical, latticed cephalic +wings, expanded between the apical horn of the cephalis and the three wings +of the thorax; they may be direct prolongations of the latter. +_Pteropilium_, however, may also be derived directly from the Dicyrtida +_Callimitra_ or _Clathrocorys_ by development of an abdomen. All these +interesting forms are closely allied to the #Plectoidea#. + + + +Subgenus 1. _Clathropilium_, Haeckel, 1881, Prodromus, p. 435. + +_Definition._--Thorax completely latticed, without three larger lateral +holes between the three wings. + + +1. _Pteropilium stratiotes_, n. sp. (Pl. 70, figs. 9, 10). + +Shell thin-walled, with two deep strictures. Length of the three joints = +1 : 5 : 4, breadth = 2 : 6 : 9. Cephalis hemispherical, with a vertical, +straight, prismatic horn of three times the length. Thorax inflated, +oblique, with three slender, nearly straight, widely divergent ribs, +beginning from the collar stricture and united in its centre with the +centripetal prolongation of the horn. The basal half of the three ribs is +enclosed in the thorax wall, whilst the distal half lies outside it, and is +connected with its lower half only by two divergent, reticulated wings. The +upper edge of the ribs is connected with the occipital horn by a vertical, +loosely reticulated, triangular wing. Abdomen half as long as the thorax, +also of irregular and oblique form, with knee-shaped outline and a wide, +truncate mouth. Network with irregular polygonal, for the most part +quadrangular, meshes, separated by thin bars and forming irregular +transverse rows. Some stronger, vein-like ribs ramify in the wall, +diverging towards the mouth. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.1, _c_ 0.08; +breadth, _a_ 0.04, _b_ 0.12, _c_ 0.18. + +_Habitat._--Central Pacific, Station 271, surface. + + +{1327}2. _Pteropilium hoplites_, n. sp. + +Shell in the general form and in the irregular, quadrangular fenestration +similar to the preceding species, but more heavy and with different +proportions. Length of the three joints = 1 : 6 : 4, breadth = 2 : 6 : 8. +Cephalis twice as broad as in _Pteropilium stratiotes_. Thorax more slender +and subovate. Abdomen truncate, conical, gradually dilated, with straight, +non-geniculate outline. Network coarser, with larger square meshes and +thicker bars. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.12, _c_ 0.08; +breadth, _a_ 0.05, _b_ 0.12, _c_ 0.16. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +3. _Pteropilium eques_, n. sp. + +Shell in the general form and in the irregular, quadrangular fenestration +similar to those of the two preceding species, but more slender and with +different proportions. Length of the three joints = 1 : 3 : 2, breadth = +2 : 4 : 4. Cephalis flatter. Thorax subconical, also flatter. Abdomen +short, cylindrical, with straight outline. Network looser than in the two +preceding species, with larger square meshes and thinner bars. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.08, _c_ 0.06; +breadth _a_ 0.06, _b_ 0.12, _c_ 0.12. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + + +Subgenus 2. _Arachnopilium_, Haeckel, 1881, Prodromus, p. 435. + +_Definition._--Thorax with three large lateral holes between the three +latticed wings. + + +4. _Pteropilium clathrocanium_, n. sp. (Pl. 64, fig. 7). + + _Arachnopilium clathrocanium_, Haeckel, Prodromus, 1881, p. 435. + +Shell very delicate, with two deep strictures. Length of the three joints = +2 : 4 : 2, breadth = 2 : 10 : 5. Cephalis subspherical, with circular, +polygonally-framed pores, and a central, three-sided pyramidal, apical horn +of twice the length. Thorax three-sided pyramidal, with three large, ovate +holes between three prominent latticed wings. From its surface arises a +very delicate, arachnoidal network with irregular, polygonal meshes, +enveloping also the entire cephalis. Abdomen wide and short, as long as the +cephalis, and half as broad as the distance of the wings, twice as broad as +the constricted mouth. + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.08, _c_ 0.04; +breadth, _a_ 0.05, _b_ 0.2, _c_ 0.1. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +{1328}Genus 587. _Theopodium_,[204] Haeckel, 1881, Prodromus, p. 435. + +_Definition._--#Theopilida# (vel Tricyrtida triradiata aperta) with three +divergent solid ribs, which lie in the wall of the thorax and the abdomen, +and are prolonged into three solid terminal feet. + +The genus _Theopodium_ and the following closely allied _Pterocanium_ +differ from the preceding four genera in the development of the three +radial rods or the primary cortinar spines, which are not free lateral +wings, but longitudinal ribs enclosed in the wall of the thorax and +abdomen, and prolonged over the basal mouth into three free terminal feet. +These are solid in _Theopodium_, which, therefore, corresponds to +_Lychnocanium_ among the Dicyrtida. + + +1. _Theopodium tricostatum_, n. sp. (Pl. 97, fig. 14). + +Shell three-sided pyramidal, thorny, with two distinct strictures. Length +of the three joints = 1 : 2 : 2, breadth = 1 : 3 : 4. Cephalis +hemispherical, with a stout conical horn of the same length. Thorax with +regular, circular, hexagonally-framed pores. Abdomen with irregular, +roundish pores of very different sizes. From the middle part of the thorax +arise the three prominent, wing-like edges of the pyramid, which are +prolonged over its wide mouth into three stout, pyramidal, divergent feet +about as long as the thorax, with dentate, lamellar edges. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.07, _c_ 0.06; +breadth, _a_ 0.04, _b_ 0.09, _c_ 0.12. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + +2. _Theopodium pyramidale_, n. sp. + +Shell three-sided pyramidal, rough, without external strictures, but with +two broad internal girdles. Length of the three joints = 1 : 2 : 6, breadth += 2 : 4 : 8. Cephalis with a thick horn of the same length, conical. Thorax +with very small, regular, circular pores. Abdomen with irregular, roundish +pores of very different sizes. From the collar stricture arise the three +rectilinear edges of the pyramid, which are prolonged over its wide-open +mouth into three stout, divergent, pyramidal feet, about as long as the +thorax. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.12; +breadth, _a_ 0.04, _b_ 0.075, _c_ 0.15. + +_Habitat._--Fossil in Barbados. + + + +Genus 588. _Pterocanium_,[205] Ehrenberg, 1847, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 54. + +_Definition._--#Theopilida# (vel Tricyrtida triradiata aperta) with three +divergent ribs, which run along the thorax and abdomen, and are prolonged +into three latticed terminal feet. + +{1329}The genus _Pterocanium_ differs from the preceding _Theopodium_ in +the fenestration of the three terminal feet, which are basal prolongations +of the three radial ribs, enclosed in the wall of the thorax and the +abdomen. Often also these ribs are partly or wholly fenestrated. It +corresponds to _Lychnodictyum_ among the Dicyrtida, and may be derived from +this by development of an abdomen. The latter forms sometimes three concave +bays, at other times three convex lobes between the three latticed feet. + + + +Subgenus 1. _Pterocanarium_, Haeckel. + +_Definition._--Free basal edge of the abdomen between the three feet +concave, forming three shallower or deeper bays between them. + + +1. _Pterocanium proserpinae_, Ehrenberg. + + _Pterocanium proserpinae_, Ehrenberg, 1858, Abhandl. d. k. Akad. d. Wiss. + Berlin, 1872, p. 299, Taf. xi. fig. 22. + + _Pterocanium proserpinae_, Haeckel, 1862, Monogr. d. Radiol., p. 332. + +Shell campanulate, rough. Length of the three joints = 1 : 4 : 2, breadth +1 : 5 : 6. Cephalis subspherical, with a triangular-pyramidal vertical horn +of thrice the length. Thorax hemispherical, without prominent swellings. +Abdomen shorter, with three concave basal bays. Pores in the thorax and +abdomen nearly equal, subregular, circular. Feet from the girdle (or the +lumbar stricture) little divergent, nearly straight. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.08, _c_ 0.04; +breadth, _a_ 0.3, _b_ 0.1, _c_ 0.12. + +_Habitat._--Mediterranean, Candia, Spratt, depth 1100 fathoms. + + +2. _Pterocanium gravidum_, n. sp., (Pl. 73, fig. 3). + +Shell campanulate, nearly three-sided pyramidal, smooth. Length of the +three joints = 1 : 4 : 3, breadth = 1 : 6 : 10. Cephalis subspherical, with +a pyramidal straight horn of twice the length. Thorax hemispherical, +without prominent swellings. Abdomen shorter, with three concave basal +bays; its network prolonged to the ends of the feet. Pores in the thorax +and abdomen of nearly equal size, irregular, roundish. Feet from the girdle +strongly divergent, with convex back. + +_Dimensions._--Length of the three joints, _a_ 0.015, _b_ 0.075, _c_ 0.06; +breadth, _a_ 0.02, _b_ 0.12, _c_ 0.2. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +3. _Pterocanium orcinum_, n. sp. (Pl. 73, fig. 2). + +Shell campanulate, nearly three-sided pyramidal, covered with conical +spines. Length of the three joints = 1 : 4 : 3, breadth = 1 : 5 : 6. +Cephalis hemispherical, with a conical horn of the same length. Thorax +without prominent swellings, with subregular, circular pores. Abdomen +{1330}shorter, with three concave basal edges and irregular, polygonal +pores. Feet from the girdle strongly divergent, nearly straight. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.08, _c_ 0.06; +breadth, _a_ 0.03, _b_ 0.1, _c_ 0.12. + +_Habitat._--Central Pacific, Station 263 to 274, depth 2350 to 2925 +fathoms. + + +4. _Pterocanium contiguum_, Ehrenberg. + + _Pterocanium contiguum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, Taf. xvii. fig. 7. + +Shell three-sided pyramidal, smooth. Length of the three joints = +1 : 3 : 2, breadth = 1 : 4 : 6. Cephalis small, subspherical, with a large +conical horn three times the length. Thorax and abdomen with small, +regular, circular pores of equal size, densely crowded together, with thin +bars. Abdomen shorter, with three concave basal edges. Feet very thick, +straight, from the girdle strongly divergent. + +_Dimensions._--Length of the three joints, _a_ 0.015, _b_ 0.05, _c_ 0.025; +breadth _a_ 0.02, _b_ 0.08, _c_ 0.12. + +_Habitat._--Fossil in Barbados. + + +5. _Pterocanium pyramis_, n. sp. (Pl. 68, fig. 7). + +Shell three-sided pyramidal, smooth. Length of the three joints = +1 : 4 : 3, breadth = 2 : 4 : 6. Cephalis hemispherical, with a conical horn +of the same length. Thorax campanulate, with fifteen to twenty prominent +longitudinal ribs, separating as many rows of regular, circular pores. +Abdomen shorter, with three concave basal bays, and irregular, roundish +pores. Feet very strong, pyramidal, straight, gradually divergent from the +girdle. + +_Dimensions._--Length of the three joints, _a_ 0.025, _b_ 0.08, _c_ 0.06; +breadth, _a_ 0.04, _b_ 0.08, _c_ 0.12. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +6. _Pterocanium virgineum_, n. sp. (Pl. 73, fig. 6). + +Shell nearly three-sided pyramidal, smooth. Length of the three joints = +1 : 4 : 8, breadth 2 : 6 : 9. Cephalis hemispherical, with a conical +straight horn three times the length. Thorax campanulate, with three slight +swellings between the three knee-shaped ribs, and with regular circular +pores. Abdomen longer, with three concave basal bays, and with very small +and numerous pores (much smaller than those of the thorax). At both sides +of the three prominent abdominal crests, two rows of larger, nearly square +pores occur. Feet slender, nearly straight, divergent. + +_Dimensions._--Length of the three joints, _a_ 0.15, _b_ 0.06, _c_ 0.12; +breadth, _a_ 0.03, _b_ 0.09, _c_ 0.14. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +7. _Pterocanium praetextum_, Haeckel. + + Lychnocanium praetextum, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 297, Taf. x. fig. 2. + +Shell nearly three-sided prismatic, smooth. Length of the three joints = +1 : 2 : 1, breadth = 1 : 4 : 4. Cephalis subspherical, with a straight, +conical horn of three times the length. Thorax {1331}campanulate with three +slight swellings between the three knee-shaped ribs, and with regular, +circular pores. Abdomen smaller, with three deep concave basal bays, and +with irregular, roundish pores. Feet longer than the shell, slender, +pyramidal, straight, parallel. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.02; +breadth, _a_ 0.02, _b_ 0.07, _c_ 0.07. + +_Habitat._--Indian Ocean, Ceylon (Haeckel); Zanzibar (Pullen). + + +8. _Pterocanium depressum_, Haeckel. + + _Lychnocanium depressum_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 297, Taf. x. fig. 1. + +Shell (including the feet) nearly three-sided prismatic, rough. Length of +the three joints = 1 : 2 : 1, breadth = 1 : 6 : 6. Cephalis subspherical, +with a conical horn of the same length. Thorax a very flat and broad +triangular pyramid, three times as broad as long. Abdomen smaller, with +three deep, parabolic, concave bays. Pores irregular, roundish. Feet longer +than the shell, slender, pyramidal, straight, parallel. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.02; +breadth, _a_ 0.025, _b_ 0.12, _c_ 0.12. + +_Habitat._--Indian Ocean, Zanzibar, depth 2200 fathoms (Pullen). + + +9. _Pterocanium campanella_, Haeckel. + + _Lychnocanium campanella_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 297, Taf. viii. fig. 12 + + _Podocyrtis campanella_, Ehrenberg, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 769. + +Shell campanulate, smooth, with three high fenestrated crests and deep +collar stricture. Length of the three joints = 1 : 3;1, breadth = +1 : 4 : 3. Cephalis subspherical, with a slender horn of the same length. +Thorax inflated, campanulate, with three vaulted swellings between the +three curved ribs. Abdomen short, with three semicircular bays between the +three feet. Pores of the whole shell regular, circular, small, and +numerous. Feet broad, triangular, shorter than the thorax, with convex back +and convergent ends. + +_Dimensions._--Length of the three joints, _a_ 0.015, _b_ 0.06, _c_ 0.2; +breadth _a_ 0.02, _b_ 0.08, _c_ 0.07. + +_Habitat._--Western Tropical Pacific, Philippine Sea, 3300 fathoms +(Brooke). + + +10. _Pterocanium tricolpum_, n. sp. (Pl. 73, fig. 1). + +Shell nearly three-sided prismatic, smooth, with three high fenestrated +crests and two deep strictures. Length of the three joints = 1 : 3 : 2, +breadth = 1 : 5 : 5. Cephalis subspherical, with an oblique, conical horn +of the same length. Thorax inflated, with three highly vaulted bosoms +between the three high crests, and with subregular, circular pores. Abdomen +shorter, with three concave (or nearly rectangular, square) basal bays +between the three feet, and with irregular, roundish pores, three to four +pairs of larger pores occurring at the sides of the base of the feet. Feet +nearly as long as the shell, with fenestrated bases, nearly straight and +parallel; somewhat convergent, with convex back. (Often the concave bays +between the three feet are not square, as in the specimen figured, but +{1332}semicircular.) The ends of the feet are sometimes strongly +convergent. The vaultings of the three swellings and the reticulation are +also variable; the whole form is often irregular. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.04; +breadth, _a_ 0.025, _b_ 0.1, _c_ 0.1. + +_Habitat._--Cosmopolitan; Atlantic, Pacific; many stations, surface. + + + +Subgenus 2. _Pterocanidium_, Haeckel. + +_Definition._--Free basal edge of the abdomen between the three feet +convex, forming three rounded or semicircular prominent lobes between them. + + +11. _Pterocanium eucolpum_, n. sp. (Pl. 73, fig. 4). + + _Dictyopodium eucolpum_, Haeckel, 1881, Prodromus et Atlas. + +Shell about triangular-prismatic, with two deep strictures, smooth. Length +of the three joints = 1 : 3 : 3, breadth = 1 : 3 : 4. Cephalis +subspherical, with a conical, oblique horn of the same length. Thorax +inflated, with three hemispherical swellings between the three crests, and +with subregular, hexagonal pores. Abdomen longer, with much smaller, +irregular, roundish pores, forming three broad, convex lobes between the +three feet. (In the figured specimen the lobes were not fully developed, +and extremely thin below the line parallel to the edge. In another +specimen, found afterwards in the same locality, the three lobes were much +larger, semicircular, and reached almost to the basal plane of the ends of +the feet by reason of their convexity.) Feet strong, with slightly convex +back, divergent. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.09, _c_ 0.1; +breadth, _a_ 0.03, _b_ 0.09, _c_ 0.12. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +12. _Pterocanium bicorne_, n. sp. (Pl. 73, fig. 5). + + _Dictyopodium bicorne_, Haeckel, 1881, Prodromus et Atlas. + +Shell nearly three-sided pyramidal, slender, smooth. Length of the three +joints = 1 : 2 : 2, breadth = 1 : 4 : 4. Cephalis hemispherical, with two +oblique, conical horns of nearly equal length. Thorax nearly hemispherical, +with slightly prominent crests, and with subregular, hexagonal pores. +Abdomen of about the same length, with much smaller, irregular, roundish +pores, forming three convex, nearly circular lobes between the three large +divergent feet. These are slender, three-sided pyramidal, longer than the +shell, fenestrated at the thickened base, with some rows of larger pores; +their back is slightly concave. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.04; +breadth, _a_ 0.02, _b_ 0.08, _c_ 0.09. + +_Habitat._--South Pacific, Station 295, depth 1500 fathoms. + + +{1333}13. _Pterocanium trilobum_, Haeckel. + + _Dictyopodium trilobum_, Haeckel, 1882, Monogr. d. Radiol., p. 340, Taf. + viii. figs. 6-10. + +Shell three-sided pyramidal, nearly tetrahedral, covered with conical +spines. Length of the three joints = 1 : 4 : 2, breadth = 1 : 6 : 10. +Cephalis hemispherical, with a large conical horn (as long as the thorax). +Thorax tetrahedral, with little prominent crests. Abdomen forming three +semicircular, convex lobes between the three feet, half as long as the +thorax, with the same irregular, roundish pores. Feet slender, about as +long as the shell, triangular, with convex back, strongly divergent, +fenestrated at the inflated and thickened base. (Compare the special +description of the living form and its soft body in my Monograph.) + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.08, _c_ 0.04; +breadth, _a_ 0.03, _b_ 0.12, _c_ 0.2. + +_Habitat._--Mediterranean, Messina, surface. + + + +Genus 589 _Pterocodon_,[206] Ehrenberg, 1847, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 54. + +_Definition._--#Theopilida# (vel Tricyrtida triradiata aperta) with three +solid free lateral wings on the thorax, and numerous solid terminal feet +around the mouth of the abdomen. + +The genus _Pterocodon_ differs from the closely allied _Pterocorys_, its +ancestral form, in the development of numerous solid feet around the +terminal mouth, similar to the terminal corona of _Calocyclas_. + + +1. _Pterocodon campana_, Ehrenberg. + + _Pterocodon campana_, Ehrenberg, 1854, Mikrogeol., Taf. xxxvi. fig. 10. + + _Pterocodon campana_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 82, Taf. xix. fig. 1. + +Shell slender, campanulate, subconical, with two distinct strictures. +Length of the three joints = 1 : 2 : 4, breadth = 2 : 3 : 5. Cephalis +hemispherical, with a conical horn of twice the length. Thorax +hemispherical, in the upper part with three divergent, conical horns, as +long as the cephalis, and curved downwards. Abdomen with four transverse +rows of large circular pores, increasing in size towards the mouth; the +largest (undermost), five times as broad as the circular thoracic pores. +Mouth not constricted, with a corona of twelve to fifteen divergent, +conical feet. + +_Dimensions._--Length of the three joints, _a_ 0.015, _b_ 0.03, _c_ 0.06; +breadth, _a_ 0.02, _b_ 0.05, _c_ 0.08. + +_Habitat._--Fossil in Barbados. + + +2. _Pterocodon ornatus_, n. sp. (Pl. 70, fig. 11). + +Shell nearly ovate, with two deep strictures. Length of the three joints = +1 : 3 : 5, breadth = 1 : 5 : 7. Cephalis hemispherical, with a large +oblique horn reaching half the length of the {1334}shell; three edges of +the horn wing-shaped and dentated. Thorax hemispherical, in the middle zone +with three conical wings, which are half as long as the thorax, and curved +downwards. Pores hexagonal, roundish, twice as broad in the inflated +abdomen as in the thorax. Mouth constricted, with a corona of from fifteen +to eighteen conical, divergent, curved feet, similar to the thoracic wings. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.1; +breadth, _a_ 0.025, _b_ 0.1, _c_ 0.14. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +3. _Pterocodon favosus_, n. sp. + +Shell ovate, with two slight strictures. Length of the three joints = +1 : 2 : 2, breadth = 2 : 4 : 4. Cephalis hemispherical, with a conical horn +of twice the length. Three wings of the thorax equal to those of the +preceding species. Pores regular, circular, hexagonally framed, of equal +size in the thorax and abdomen. Mouth constricted, with a corona of nine +straight, conical, nearly vertical feet. + +_Dimensions._--Length of the three joints, _a_ 0.0025, _b_ 0.05, _c_ 0.05; +breadth, _a_ 0.05, _b_ 0.09, _c_ 0.1. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + + +Genus 590. _Dictyocodon_,[207] Haeckel, 1881, Prodromus, p. 435. + +_Definition._--#Theopilida# (vel Tricyrtida triradiata aperta) with three +latticed free lateral wings on the thorax, and numerous latticed terminal +feet around the mouth of the abdomen. + +The genus _Dictyocodon_, one of the most elegant among the NASSELLARIA, +differs from the preceding _Pterocodon_ in the fenestration of the three +lateral wings of the thorax, and the numerous terminal feet of the abdomen. +It may be derived from _Dictyoceras_ by development of regular lattice-feet +around the terminal mouth. + + + +Subgenus 1. _Dictyocodella_, Haeckel. + +_Definition._--The three lateral lattice-wings arise from the thorax alone. + + +1. _Dictyocodon annasethe_, n. sp. (Pl. 71, fig. 11). + +Shell with two deep strictures. Length of the three joints = 2 : 5 : 4, +breadth = 1 : 5 : 6. Cephalis subspherical, with a very large, three-sided +prismatic horn of three times the length, bearing at the base some smaller +accessory spines. Thorax nearly conical, with three large, inflated, +triangular lattice-wings, the upper edge of which (the cortinar rod) +descends obliquely, and is larger {1335}than the thorax, ending in a spine. +Abdomen inflated, subcylindrical, divided at the wide open mouth by nine +deep incisions into nine large triangular feet. Network in the thorax and +wings composed of small, regular, hexagonal pores, in the abdomen of three +transverse rows of irregular, very large pores, which are surrounded and +separated by bands of very small pores; in each foot one large pore and a +marginal series of very small pores occur. I dedicate this wonderful +species to the memory of my dear wife, Anna Sethe. + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.1, _c_ 0.08; +breadth, _a_ 0.03, _b_ 0.1, _c_ 0.12. + +_Habitat._--Indian Ocean; Cocos Islands (Rabbe), surface. + + +2. _Dictyocodon carolotae,_ n. sp. (Pl. 71, fig. 14). + +Shell with two deep strictures. Length of the three joints = 1 : 3 : 7, +breadth = 2 : 5 : 6. Cephalis hemispherical, with an oblique pyramidal horn +of twice the length. Thorax subconical, in the upper half with three +divergent, triangular wings of half the length, the upper edge of which is +nearly horizontal, little curved. Abdomen nearly cylindrical; divided at +the wide open mouth by nine deep incisions into nine triangular, vertical +feet, about as large as the wings. Network very delicate, with regular, +small, circular pores of equal size and very thin bars. I dedicate this +elegant species to my dear mother, Charlotte Sethe. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.14; +breadth, _a_ 0.04, _b_ 0.1, _c_ 0.12. + +_Habitat._--Cape of Good Hope (Bleek), surface. + + + +Subgenus 2. _Dictyocodoma_, Haeckel. + +_Definition._--The three lateral wings are prolonged from the thorax to the +abdomen. + + +3. _Dictyocodon palladius_, n. sp. (Pl. 71, figs. 12, 13). + +Shell with distinct collar, but evanescent lumbar stricture. Length of the +three joints = 1 : 2 : 7, breadth = 1 : 3 : 8. Cephalis very small, with a +large pyramidal horn of twice the length, bearing at its base some small, +often branched, accessory spines. Thorax three-sided pyramidal, without +external boundary prolonged into the large, inflated, gradually dilated +abdomen. The internal boundary between the two is marked by a fenestrated, +horizontal ring (not indicated in the figure). Three prominent, triangular, +fenestrated wings arise from the base of the cephalic horn, and are +prolonged nearly through the whole shell almost to the edge of the mouth; +in its lower half they form three elevated fenestrated apophyses, the upper +edge of which is nearly horizontal. Mouth divided by about twenty incisions +into as many triangular, vertical, fenestrated feet. The network of the +whole shell is very delicate, like fine gauze, composed of very small, +regular, hexagonal pores. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.055, _c_ 0.21; +breadth, _a_ 0.03, _b_ 0.09, _c_ 0.25. + +_Habitat._--Central Pacific, Station 271, surface. + + +{1336}4. _Dictyocodon prometheus,_ n. sp. + +Shell tower-shaped, very similar to the preceding species in form and +fenestration, but more slender and different in the longer and three-sided +prismatic abdomen. Length of the three joints = 1 : 1 : 8, breadth = +1 : 3 : 7. Cephalis with two large divergent horns of three times the +length, which are united by interior prolongations with the basal central +point, from which arise the upper edges of the three divergent wings; the +ends of the latter are directed downwards. Mouth with a corona of about +thirty irregular, triangular feet. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.03, _c_ 0.025; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.2. + +_Habitat._--Tropical Atlantic, Station 347, surface. + + + +Genus 591. _Pleuropodium_,[208] Haeckel, 1881, Prodromus, p. 436. + +_Definition._--#Theopilida# (vel Tricyrtida triradiata aperta) without ribs +in the thorax, but with three ribs enclosed in the abdomen, which are +prolonged into three terminal feet. + +The genus _Pleuropodium_, formerly confounded with _Theopodium_ and +_Pterocanium_, differs from these two closely allied ancestral genera in +the localisation of the three lateral ribs, which have disappeared in the +thorax and become limited to the abdomen. It is therefore intermediate +between the former and the following _Podocyrtis_. + + +1. _Pleuropodium charybdeum_, Haeckel. + + _Pterocanium charybdeum_, J. Mueller, 1858, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 43, Taf. vi. figs. 7-10. + + _Podocyrtis charybdea_, J. Mueller, 1856, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, p. 492. + +Shell campanulate, armed with scattered, bristle-shaped spines, with sharp +collar and slight lumbar stricture. Length of the three joints = 1 : 3 : 1, +breadth = 1 : 4 : 5. Cephalis cupola-shaped, with a large prismatic, +somewhat curved horn, half as long as the shell. Thorax hemispherical, +spiny. Abdomen short and wide, three-sided prismatic, with three stout +longitudinal ribs, which are prolonged into three slender, prismatic, +nearly vertical, slightly curved feet, about as long as the shell. Pores +irregular, roundish, of variable size. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.03; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.1. + +_Habitat._--Mediterranean (Messina, Nice, &c.), surface. + + +2. _Pleuropodium cortina_, n. sp. + +Shell campanulate, smooth, with two distinct strictures. Length of the +three joints = 1 : 4 : 2, breadth = 1 : 3 : 4. Cephalis subspherical, with +a small, pyramidal, straight horn of the same length. {1337}Thorax +pear-shaped, with regular, circular, hexagonally-framed pores. Abdomen +three-sided pyramidal, with irregular, roundish pores and three prominent, +stout, prismatic ribs, which are prolonged into three straight, divergent +feet of the same length. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.08, _c_ 0.04; +breadth _a_ 0.025, _b_ 0.06, _c_ 0.08. + +_Habitat._--North Atlantic, Station 354, surface. + + + +Genus 592. _Podocyrtis_,[209] Ehrenberg, 1847, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 54. + +_Definition._--#Theopilida# (vel Tricyrtida triradiata aperta) with three +simple, terminal feet on the mouth of the abdomen, without lateral ribs or +wings. Apex with a horn, which usually is simple. + +The genus _Podocyrtis_, and the two following closely allied genera, differ +from all the preceding Theopilida in the absence of lateral ribs or wings, +and the possession of three free terminal feet, which arise directly from +the peristome, or from the margin of the abdominal mouth. They may be +derived from _Pleuropodium_ by reduction and loss of the three piercing +lateral ribs, the terminal free prolongations of which only remain. The +genus _Podocyrtis_ is one of the largest and most common among all +#Cyrtoidea#, being rich mainly in fossil forms. Ehrenberg in his +Polycystins of Barbados (1875, _loc. cit._, p. 80) enumerated not less than +thirty-one species. Some of these are yet living, and occur in the Pacific +Radiolarian ooze collected by the Challenger. Other new forms are to be +added, so that the number of species described in the following pages +amounts to forty-five. Many of these are cosmopolitan, or at least common +and widely distributed. To facilitate study we may divide this large genus +into four subgenera: in two of these the terminal feet are divergent, or +nearly parallel; in the two others convergent. In each of these two groups +the pores of the thorax and the abdomen are either nearly equal in size and +form, or distinctly different, the abdominal pores being often much larger +than the thoracic. The small cephalis bears constantly an apical horn, +which is usually simple, rarely branched. + + + +Subgenus 1. _Podocyrtarium_, Haeckel. + +_Definition._--Feet divergent (the distance between their ends being +greater than that between their bases). Pores of the thorax and abdomen +nearly equal in size and similar in form. + + +{1338}1. _Podocyrtis tripodiscus_, n. sp. (Pl. 72, fig. 4). + +Shell nearly conical, gradually dilated from the apical to the basal part, +with two slight strictures. Surface a little rough. Length of the three +joints = 1 : 2 : 4, breadth = 2 : 4 : 6. Pores subregular, circular, +quincuncially disposed, of nearly equal size in the conical thorax and the +subspherical abdomen. Cephalis hemispherical, with smaller pores and a +spindle-shaped spiny horn of twice the length. Feet cylindrical, as long as +the abdomen, little divergent, their ends curved outwards and thickened +into a papillate knob. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.03, _c_ 0.08; +breadth, _a_ 0.03, _b_ 0.07, _c_ 0.11. + +_Habitat._--Central Pacific, Station 265 to 272, depth 2425 to 2925 +fathoms. + + +2. _Podocyrtis attenuata_, Ehrenberg. + + _Podocyrtis attenuata_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 80, Taf. xvi. fig. 5. + +Shell nearly conical, gradually dilated from the apical to the basal part, +with two slight strictures. Surface a little rough. Length of the three +joints = 2 : 3 : 4, breadth = 2 : 4 : 5. Pores subregular, circular, equal, +quincuncial. Cephalis subspherical, with a conical horn of twice the +length. Feet cylindrical, as long as the abdomen, little divergent +(sometimes as in the specimen figured, nearly parallel). + +_Dimensions._--Length of the three joints, _a_ 0.015, _b_ 0.03, _c_ 0.04; +breadth, _a_ 0.02, _b_ 0.04, _c_ 0.05. + +_Habitat._--Fossil in Barbados. + + +3. _Podocyrtis thyrsoceras_, n. sp. + +Shell slender, conical, smooth, very similar to _Thyrsocyrtis rhizodon_, +Ehrenberg (1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 84, Taf. xii. +fig. 1), with two slight strictures, nearly of the same form and +fenestration as in the preceding smaller species. Length of the three +joints = 1 : 2 : 3, breadth = 1 : 3 : 4. Cephalis subspherical, with a +large cylindrical straight horn, which reaches the length of the abdomen, +and is papillate in the distal half. Feet cylindrical, divergent, nearly as +long as the whole shell, broadened and spinulated at the distal end. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.06; +breadth, _a_ 0.02, _b_ 0.06, _c_ 0.08. + +_Habitat._--South Pacific, Station 295, depth 1500 fathoms. + + +4. _Podocyrtis conica_, n. sp. + +Shell conical, without external strictures, but with two internal septal +rings. Surface papillate. Length of the three joints = 2 : 3 : 8, breadth = +3 : 6 : 10. Pores equal, subregular, circular, quincuncial. Cephalis +hemispherical, with a thick conical horn of the same length. Feet conical, +about as long as the thorax, divergent in the direction of the outline of +the conical shell. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.03, _c_ 0.08; +breadth, _a_ 0.03, _b_ 0.06, _c_ 0.1. + +_Habitat._--Cosmopolitan, Central Pacific, Stations 263 to 274; Tropical +Atlantic, Station 348, in depths between 2350 and 2925 fathoms; also fossil +in Barbados. + + +{1339}5. _Podocyrtis corythaeola_, n. sp. (Pl. 72, fig. 2). + +Shell ovate conical, with two deep strictures, and with rough surface. +Length of the three joints = 2 : 5 : 8, breadth = 3 : 8 : 10. Cephalis +hemispherical, thorny, with a strong oblique horn three times the length, +which is armed with nine to twelve conical spines. Pores small, circular, +of irregular size and distribution. Feet spindle-shaped, divergent, as long +as the inflated abdomen. + +_Dimensions._--Length of the three feet, _a_ 0.02, _b_ 0.05, _c_ 0.08; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.1. + +_Habitat._--Indian Ocean, Maldive Islands (Haeckel), surface. + + +6. _Podocyrtis surena_, n. sp. (Pl. 72, fig. 10). + +Shell thin-walled, tower-shaped, smooth, with two deep strictures. Length +of the three joints = 2 : 5 : 10, breadth = 3 : 10 : 11. Cephalis +subspherical, with a bent conical horn, as long as the hemispherical +thorax. Abdomen cylindrical. Pores subregular, circular, quincuncially +disposed, and slightly larger in the abdomen. Feet with a thickened calf, +nearly perpendicular, as long as the thorax; their distal ends little +divergent, and forming a knob beset with small roundish tubercles. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.05, _c_ 0.1; +breadth, _a_ 0.035, _b_ 0.1, _c_ 0.11. + +_Habitat._--North Pacific, Station 241, depth 2300 fathoms. + + +7. _Podocyrtis conulus_, n. sp. + +Shell elongate, conical, rough, without external strictures, but with two +internal septal rings. Length of the three joints = 3 : 4 : 15, breadth = +5 : 7 : 12. Cephalis hemispherical, with a thick pyramidal horn of the same +length. Feet also pyramidal, divergent, of the same size as the horn. Pores +irregular, roundish, of variable size. Abdomen very long. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.04, _c_ 0.15; +breadth, _a_ 0.05, _b_ 0.07, _c_ 0.12. + +_Habitat._--Tropical Atlantic, Station 342, depth 1445 fathoms; also fossil +in Barbados. + + +8. _Podocyrtis tridactyla_, n. sp. + +Shell conical, with two slight strictures, smooth. Length of the three +joints = 2 : 6 : 5, breadth = 4 : 5 : 6. Cephalis hemispherical, with a +pyramidal horn of twice the length. Pores irregular, polygonal, of variable +size. Feet as long as the abdomen, constricted in the middle, trilobed at +the distal end; the middle lobe twice as large as the lateral lobes. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.05; +breadth, _a_ 0.04, _b_ 0.05, _c_ 0.06. + +_Habitat._--Indian Ocean, Madagascar, Rabbe. + + + +Subgenus 2. _Podocyrtecium_, Haeckel. + +_Definition._--Feet divergent (the distance between their ends being +greater than that between their bases). Pores of the thorax and abdomen of +different form or size. + + +{1340}9. _Podocyrtis prismatica_, n. sp. (Pl. 72, fig. 1). + +Shell conical, rough, with two distinct strictures. Length of the three +joints = 1 : 1 : 3, breadth = 1 : 2 : 5. Cephalis subspherical, with a +curved conical horn of twice the length. Thorax and abdomen together nearly +hemispherical. Pores small, regular, circular, quincuncial, twice as large +in the abdomen as in the thorax. Feet very large, twice as long as the +whole shell, divergent, bent outwards, prismatic, with strong prominent +edges. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.02, _c_ 0.06; +breadth, _a_ 0.02, _b_ 0.04, _c_ 0.1. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +10. _Podocyrtis brevipes_, Ehrenberg. + + _Podocyrtis brevipes_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 80, Taf. xvi. fig. 6. + +Shell conical, smooth, with two slight strictures. Length of the three +joints = 2 : 3 : 6, breadth = 2 : 5 : 9. Cephalis subspherical, with a +conical horn of the same length. Pores regular, circular, quincuncial, +three times as broad in the abdomen as in the thorax. Feet short, +triangular, divergent, as long as the horn. (The specimen figured by +Ehrenberg was incomplete, one foot and the horn being broken off.) + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.03, _c_ 0.06; +breadth, _a_ 0.02, _b_ 0.05, _c_ 0.09. + +_Habitat._--Fossil in Barbados. + + +11. _Podocyrtis divergens_, n. sp. (Pl. 72, fig. 6). + +Shell slender, subconical, thick-walled, with two distinct strictures. +Length of the three joints = 2 : 5 : 7, breadth = 4 : 8 : 10. Cephalis +hemispherical, with a large, oblique, prismatic horn three times the +length, and a small divergent by-horn at its base. Thorax hemispherical, +rough, with regular, circular, quincuncial pores. Abdomen cylindrical, +thorny, with larger circular pores of subregular disposition, two to three +times as broad as those of the thorax. Feet conical, horn-like, bent, as +long as the abdomen; strongly divergent in the distal half. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.05, _c_ 0.07; +breadth, _a_ 0.04, _b_ 0.08, _c_ 0.1. + +_Habitat._--Western Tropical Pacific, Station 220, depth 1100 fathoms. + + +12. _Podocyrtis collaris_, Ehrenberg. + + _Podocyrtis collaris_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 82, Taf. xvi. fig. 1. + +Shell conical, with slight collar and deeper lumbar stricture. Length of +the three joints = 1 : 4 : 4, breadth = 1 : 4 : 8. Cephalis hemispherical, +with a small oblique horn of the same length. Pores regular, circular, +quincuncial, four to six times as broad in the inflated abdomen as in the +conical thorax. Feet short and slightly divergent, little longer than the +cephalis. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.07, _c_ 0.08; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.16. + +_Habitat._--Fossil in Barbados. + + +{1341}13. _Podocyrtis ventricosa_, Ehrenberg. + + _Podocyrtis ventricosa_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 82, Taf. xvi. fig. 3. + +Shell conical, with two deep strictures, thorny. Length of the three joints += 1 : 2 : 5, breadth = 1 : 4 : 8. Cephalis subspherical, with a small +conical horn of the same length. Pores regular circular, quincuncial, four +to six times as broad in the inflated abdomen as in the hemispherical +thorax. (Pores much larger and less numerous than in the similar preceding +species.) Feet broad and stout, triangular, divergent, as long as the +thorax. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.1; +breadth, _a_ 0.025, _b_ 0.07, _c_ 0.16. + +_Habitat._--Fossil in Barbados. + + +14. _Podocyrtis flosculata_, n. sp. (Pl. 72, fig. 9). + +Shell conical, rough, as broad as long, with distinct collar, but +obliterated lumbar stricture. Length of the three joints = 1 : 2 : 4, +breadth = 2 : 4 : 7. Cephalis hemispherical, with a thick conical horn of +the same length. Thorax truncate, conical, with small, circular, +quincuncial pores. Abdomen inflated, with very large and remarkable +regular, quincuncial pores; their inner edge circular, the outer six-lobed, +the six lobes elegantly alternating with six short conical spines. Feet +very coarse, equilateral triangular, half as broad as the thorax, little +divergent. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.08; +breadth, _a_ 0.04, _b_ 0.08, _c_ 0.14. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +15. _Podocyrtis centriscus_, Ehrenberg. + + _Podocyrtis centriscus_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 80, Taf. xiv. fig. 2. + +Shell conical, rough, about as high as broad, with two obliterated +strictures. Length of the three joints = 1 : 2 : 4, breadth = 1 : 4 : 7. +Cephalis small, hemispherical, with a stout conical horn. Pores of the +inflated abdomen irregular, roundish, very large, three occurring in the +course of its length, five times as broad as the small, very numerous, +regular, circular pores of the conical thorax. Feet S-shaped, as long as +the abdomen, with the blunt end curved outwards. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.08; +breadth, _a_ 0.02, _b_ 0.08, _c_ 0.14. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms; fossil in +Barbados. + + +16. _Podocyrtis magnifica_, n. sp. (Pl. 72, fig. 5). + +Shell conical, spiny, a little longer than broad, with two distinct +strictures. Length of the three joints = 1 : 2 : 5, breadth = 2 : 4 : 7. +Cephalis hemispherical, with a large conical horn, which is as long as the +abdomen, nearly scaly, and covered with short, simple, and bifid spines. +Pores regular, circular, quincuncially disposed, four times as broad in the +inflated abdomen as in the {1342}conical thorax. Spines of the former twice +as large as those of the latter. Feet very long and slender, cylindrical, +S-shaped, bent outwards at the thickened distal end, with a spindle-shaped +papillate knob. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.04, _c_ 0.1; +breadth, _a_ 0.04, _b_ 0.08, _c_ 0.14. + +_Habitat._--Canary Islands, Lanzerote, Haeckel, surface. + + +17. _Podocyrtis princeps_, Ehrenberg. + + _Podocyrtis princeps_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 82, Taf. xiii. fig. 1. + + _Podocyrtis princeps_, Buetschli, 1882, Zeitschr. f. wiss. Zool., vol. + xxxvi. p. 540, Taf. xxxiii. fig. 32. + +Shell conical, with two distinct strictures. Length of three joints = +1 : 2 : 5, breadth = 1 : 4 : 7. Cephalis subspherical, with a large +cylindrical, vertical horn, longer than the whole shell. Pores regular, +circular, quincuncial, in the inflated spiny abdomen very large (four to +five in the course of its length), five times as broad as in the smooth +conical thorax. Feet about as long as the shell, slightly bent, S-shaped, +cylindrical. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.05, _c_ 0.1; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.14. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms; fossil in +Barbados. + + +18. _Podocyrtis euceros_, Ehrenberg. + + _Podocyrtis euceros_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 82, Taf. xv. fig. 1. + +Shell conical, campanulate, with two deep strictures. Length of the three +joints = 1 : 3 : 6, breadth = 2 : 5 : 7. Cephalis hemispherical, with a +large, cylindrical horn, nearly as long as the shell. Pores regular, +circular, hexagonally framed, quincuncial, four times as broad in the +papillated, inflated abdomen as in the hemispherical, smooth thorax. Feet +short and broad, triangular, divergent, about as long as the thorax. (In +the specimen figured by Ehrenberg, two feet were broken off). + +_Dimensions._--Length of the three joints, _a_ 0.016, _b_ 0.05, _c_ 0.1; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.12. + +_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Indian, and Pacific +Oceans, at many stations, and in various depths; fossil in Barbados. + + +19. _Podocyrtis cristata_, n. sp. (Pl. 72, fig. 7). + +Shell conical-campanulate, thorny, with two deep strictures. Length of the +three joints = 1 : 2 : 5, breadth = 2 : 4 : 7. Cephalis subspherical, with +a large, oblique, little bent, conical horn, as long as the abdomen. Thorax +hemispherical, papillate, with small, regular, circular pores. Abdomen +inflated, with very large, circular pores, (three to four in its length), +six times as broad as those of the thorax, and separated by hexagonal, +serrated crests. Feet cylindrical, stout, S-shaped, slightly divergent, +with a spherical papillate knob at the distal end. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.1; +breadth, _a_ 0.035, _b_ 0.07, _c_ 0.14. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +{1343}20. _Podocyrtis schomburgkii_, Ehrenberg. + + _Podocyrtis schomburgkii_, Ehrenberg, 1854, Mikrogeol., Taf. xxxvi. fig. + 22; Abhandl. d. k. Akad. d. Wiss. Berlin, 1875, p. 82, Taf. xiv. 7. + +Shell ovate-conical, with two distinct strictures. Length of the three +joints = 2 : 5 : 10, breadth = 3 : 8 : 12. Cephalis hemispherical, with a +large, straight, conical horn as long as the abdomen. Thorax campanulate, +smooth, with small, regular, circular pores. Abdomen inflated, papillate, +with very large, regular, hexagonal pores (three to four in the course of +its length), five times as broad as their bars and as the pores of the +thorax. Feet as long as the abdomen, nearly parallel, slightly bent +outwards at the conical distal end. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.05, _c_ 0.1; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.12. + +_Habitat._--Fossil in Barbados. + + +21. _Podocyrtis hexagonalis_, n. sp. + +Shell nearly ovate, slender, everywhere covered with a regular network of +high, hexagonal, denticulated crests, separating the circular, +funnel-shaped pores, which are twice as large in the subspherical abdomen +as in the hemispherical thorax, between both of which are two deep +strictures. Length of the three joints = 1 : 3 : 6, breadth = 2 : 5 : 6. +Cephalis hemispherical, with a long and thin cylindrical, vertical horn, as +long as the abdomen. Feet of the same length and form, nearly straight, +slightly divergent. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.12; +breadth, _a_ 0.04, _b_ 0.11, _c_ 0.13. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +22. _Podocyrtis ovata_, n. sp. + +Shell nearly ovate, papillate, without external strictures. Length of the +three joints = 1 : 2 : 3, breadth = 2 : 4 : 5. Cephalis hemispherical, with +a pyramidal horn half as long as the shell. Pores regular, circular, +hexagonally framed, three times as broad in the inflated abdomen as in the +conical thorax. Feet pyramidal, little bent, divergent, about as long as +the thorax. + +_Dimensions._--Length of the three joints, _a_ 0.025, _b_ 0.05, _c_ 0.08; +breadth, _a_ 0.05, _b_ 0.095, _c_ 0.12. + +_Habitat._--Mediterranean, Corfu, Haeckel, surface. + + +23. _Podocyrtis urceolata_, n. sp. + + ? _Podocyrtis mitra_, Bury, 1862, Polycystins of Barbados, pl. v. fig. 3. + +Shell nearly ovate, smooth, with two deep strictures. Length of the three +joints = 1 : 2 : 6, breadth = 2 : 4 : 5. Cephalis subspherical, with a +stout, conical horn of the same length. Thorax flat, hemispherical, with +four to six transverse rows of small circular pores. Abdomen urceolate, +{1344}with four to five transverse rows of very large, subregular, +hexagonal pores. Feet short and thick, bent outwards, as long as the +thorax. + +_Dimensions._--Length of the three joints, _a_ 0.025, _b_ 0.05, _c_ 0.15; +breadth, _a_ 0.05, _b_ 0.1, _c_ 0.13. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms; fossil in +Barbados. + + +24. _Podocyrtis ehrenbergii_, Haeckel. + + _Podocyrtis amphiacantha_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 80, Taf. xvii. fig. 3. + +Shell slender, ovate, smooth, with deep collar, but evanescent lumbar +stricture. Length of the three joints = 1 : 3 : 2, breadth = 1 : 3 : 3. +Cephalis subspherical, with a large conical horn, as long as the +campanulate thorax. Abdomen nearly cylindrical. Pores irregular, roundish, +two to four times as large in the abdomen as in the thorax. Feet conical, +slender, divergent, nearly as long as the shell. (In the imperfect specimen +figured by Ehrenberg, two spines were broken off.) + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.04; +breadth, a 0.02, _b_ 0.06, _c_ 0.06. + +_Habitat._--North Pacific, Station 253, depth 3125 fathoms; fossil in +Barbados. + + +25. _Podocyrtis argulus_, Ehrenberg. + + _Podocyrtis argulus_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 80, Taf. xvi. fig. 2. + +Shell slender, ovate, or subconical, with two deep strictures. Length of +the three joints = 1 : 2 : 4, breadth = 1 : 3 : 4. Cephalis hemispherical, +with a small conical horn of the same length (broken off in the figure of +Ehrenberg). Pores regular, circular, three times as broad in the inflated +abdomen as in the campanulate thorax. Feet spindle-shaped, slender, +divergent, about as long as the thorax. + +_Dimensions._--Length of the three joints, _a_ 0.025, _b_ 0.05, _c_ 0.1; +breadth, _a_ 0.03, _b_ 0.07, _c_ 0.1. + +_Habitat._--Tropical Atlantic, Station 247, depth 2530 fathoms; also fossil +in Barbados. + + + +Subgenus 3. _Podocyrtidium_, Haeckel. + +_Definition._--Feet convergent (the distance between their ends being +smaller than that between their bases). Pores of the thorax and abdomen +nearly equal in size and similar in form. + + +26. _Podocyrtis papalis_, Ehrenberg. + + _Podocyrtis papalis_, Ehrenberg, Mikrogeol., Taf. xxxvi. fig. 23; + Abhandl. d. k. Akad. d. Wiss. Berlin, 1875, p. 82, Taf. xv. fig. 6. + +Shell ovate, smooth, without external stricture. Length of the three joints += 1 : 3 : 1, breadth = 1 : 3 : 3. Cephalis ovate, with a stout pyramidal +horn of twice the length. Thorax and {1345}abdomen with about thirty +longitudinal, divergent ribs, separating the same number of longitudinal +rows of regular, circular pores, the size of which increases gradually +towards the base. Feet shovel-shaped (broad, triangular, with convex outer +and concave inner side, the obtuse end being curved inwards), about as long +as the short abdomen, only slightly convergent. + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.12, _c_ 0.04; +breadth, _a_ 0.04, _b_ 0.12, _c_ 0.11. + +_Habitat._--Fossil in Barbados. + + +27. _Podocyrtis costata_, n. sp. + +Shell ovate, smooth, of the same form and structure as _Podocyrtis +papalis_, but with two distinct strictures and different proportions. +Length of the three joints = 1 : 3 : 6, breadth = 2 : 4 : 6. About thirty +longitudinal ribs regularly alternating with rows of circular, regular +pores. Feet as in _Podocyrtis papalis_. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.12; +breadth, _a_ 0.04, _b_ 0.08, _c_ 0.12. + +_Habitat._--Central Pacific, Stations 266 to 272, depth 2425 to 2925 +fathoms. + + +28. _Podocyrtis mitrella_, Ehrenberg. + + _Podocyrtis mitrella_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 82, Taf. xv. fig. 3. + +Shell ovate, smooth, nearly of the same form and structure as _Podocyrtis +papalis_, but different in the proportions of the joints, in the much +smaller, regular pores, and in the great breadth of the shovel-shaped, +blunt, about semicircular feet. Length of the three joints = 2 : 9 : 4, +breadth = 3 : 10 : 3. Cephalis subspherical, with a thick pyramidal horn of +the same length. Slight collar, but no lumbar stricture. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.09, _c_ 0.04; +breadth, _a_ 0.03, _b_ 0.1, _c_ 0.03. + +_Habitat._--Fossil in Barbados. + + +29. _Podocyrtis mitra_, Ehrenberg. + + _Podocyrtis mitra_, Ehrenberg, 1854, Mikrogeol., Taf. xxxvi. fig. 20; + Abhandl. d. k. Akad. d. Wiss. Berlin, 1875, p. 82, Taf. xv. fig. 4. + +Shell ovate, conical, smooth, with two slight strictures. Length of the +three joints = 1 : 2 : 3, breadth = 1 : 3 : 4. Cephalis with the horn (of +equal length) conical. Pores regular, circular, in about twenty +longitudinal rows, slightly increasing in size in the middle part of the +abdomen. Feet shovel-shaped, blunt, slightly divergent, only as long as the +cephalis. + +_Dimensions._--Length of the three joints, _a_ 0.025, _b_ 0.5, _c_ 0.7; +breadth, _a_ 0.03, _b_ 0.075, _c_ 0.1. + +_Habitat._--Cosmopolitan; Mediterranean (Gibraltar), Canary Islands, +Central Pacific, Stations 265 to 274, in different depths; also fossil in +Barbados. + + +{1346}30. _Podocyrtis argus_, Ehrenberg. + + _Podocyrtis argus_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 82, Taf. xvi. fig. 9. + +Shell ovate, with two distinct strictures, smooth. Length of the three +joints = 1 : 3 : 4, breadth = 1 : 4 : 5. Cephalis subconical, with a +conical horn of the same length. Thorax campanulate. Abdomen inflated. +Pores subregular, roundish, of nearly equal breadth, quincuncial. Feet +shovel-shaped, triangular, nearly vertical, only as long as the cephalis. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.08; +breadth, _a_ 0.025, _b_ 0.08, _c_ 0.1. + +_Habitat._--Tropical Atlantic, Station 347, surface; fossil in Barbados. + + +31. _Podocyrtis eulophos_, Ehrenberg. + + _Podocyrtis eulophos_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 82, Taf. xiv. fig. 6. + +Shell subconical, slender, with two slight strictures, smooth. Length of +the three joints = 1 : 2 : 6, breadth = 2 : 4 : 6. Cephalis hemispherical, +with a large, spindle-shaped, angular horn of twice the length. Thorax +hemispherical. Abdomen truncate, conical. Pores subregular, roundish, in +about twenty longitudinal rows, their breadth gradually increasing towards +the base. Feet shovel-shaped, blunt, nearly vertical, only as long as the +cephalis. + +_Dimensions._--Length of the three joints, _a_ 0.025, _b_ 0.05, _c_ 0.16; +breadth, _a_ 0.05, _b_ 0.08, _c_ 0.14. + +_Habitat._--Fossil in Barbados. + + +32. _Podocyrtis favosa_, n. sp. + +Shell ovate, with two slight strictures, and with honeycomb-like surface. +Length of the three joints = 1 : 5 : 2, breadth = 2 : 6 : 5. Cephalis +hemispherical, with a pyramidal horn of twice the length. Thorax +hemispherical. Pores regular, circular, hexagonally framed, funnel-shaped, +with high, prominent crests between them. Feet shovel-shaped, little +convergent, triangular, as long as the abdomen. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.1, _c_ 0.04; +breadth, _a_ 0.04, _b_ 0.12, _c_ 0.11. + +_Habitat._--South Pacific, Station 300, depth 1375 fathoms. + + +33. _Podocyrtis fusiformis_, n. sp. + +Shell slender, nearly spindle-shaped, diminishing gradually from the +broadest middle part (immediately above the lumbar septum) towards the two +poles. Length of the three joints = 1 : 5 : 8, breadth = 2 : 6 : 5. +Cephalis subspherical, with a large conical horn three times the length. +Thorax and abdomen with twenty-four to thirty denticulated, longitudinal +ribs, separating the same number of longitudinal rows of regular, circular +pores. Instead of the lumbar stricture, a broad, internal septum occurs. +Feet slender, straight, as long as the abdomen, only slightly convergent. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.1, _c_ 0.16; +breadth, _a_ 0.05, _b_ 0.12, _c_ 0.1. + +_Habitat._--Indian Ocean, Madagascar (Rabbe) surface. + + + +{1347}Subgenus 4. _Podocyrtonium_, Haeckel. + +_Definition._--Feet convergent (the distance between their ends being +smaller than that between their bases). Pores of the thorax and abdomen +different in size or form. + + +34. _Podocyrtis pedicellaria_, n. sp. (Pl. 72, fig. 8). + +Shell conical, ovate, with two very slight strictures. Length of the three +joints = 2 : 3 : 8, breadth = 2 : 4 : 8. Cephalis conical, with a pyramidal +horn of the same length. Pores subregular, circular, quincuncially +disposed, two to three times as broad in the smooth abdomen as in the +rough, spinulate thorax. Feet as long as the thorax, shovel-shaped (broad, +triangular, with convex outer and concave inner side, the free ends being +curved inwards), only slightly convergent. + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.05, _c_ 0.16; +breadth, _a_ 0.05, _b_ 0.09, _c_ 0.16. + +_Habitat._--Central Pacific, Stations 265 to 268, depth 2700 to 2900 +fathoms. + + +35. _Podocyrtis sinuosa_, Ehrenberg. + + _Podocyrtis sinuosa_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 82, Taf. xv. fig. 5. + + _Podocyrtis sinuosa_, Buetschli, 1882, Zeitschr. f. wiss. Zool., vol. + xxxvi. p. 540, Taf. xxxiii. fig. 33. + +Shell slender, conical, with slight collar, but without lumbar stricture. +Length of the three joints = 1 : 2 : 4, breadth = 1 : 2 : 4. Cephalis +subspherical (in the figure of Ehrenberg broken off), with a pyramidal horn +of the same length. Pores subregular, circular, four times as broad in the +abdomen as in the thorax. Feet shovel-shaped, as long as the thorax. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.06, _c_ 0.12; +breadth, _a_ 0.03, _b_ 0.06, _c_ 0.12. + +_Habitat._--Fossil in Barbados. + + +36. _Podocyrtis floribunda_, n. sp. + +Shell ovate, conical, with two very slight strictures. Length of the three +joints = 2 : 3 : 6, breadth = 2 : 4 : 7. Between twenty-four to thirty +longitudinal, denticulated ribs lie the same number of subregular pores, +which are flower-like, lobed, or rosette-shaped, and two to three times as +large in the abdomen as in the thorax. Feet shovel-shaped (as in the +similar _Podocyrtis pedicellaria_ (Pl. 72, fig. 8). + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.05, _c_ 0.12; +breadth, _a_ 0.04, _b_ 0.08, _c_ 0.14. + +_Habitat._--Tropical Atlantic, Station 342, depth 1445 fathoms; also fossil +in Barbados. + + +37. _Podocyrtis scaphopodia_, n. sp. + +Shell conical, rough, with two slight strictures. Length of the three +joints = 2 : 3 : 5, breadth = 2 : 4 : 8. Cephalis subspherical, with a +pyramidal horn of twice the length. Pores subregular, {1348}circular, +quincuncial, four times as large in the abdomen as in the thorax. Feet +short and broad, triangular, shovel-shaped, with convergent ends. This +species is similar to _Podocyrtis brevipes_, but differs in the form and +size of the horn and of the feet. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.03, _c_ 0.05; +breadth, _a_ 0.02, _b_ 0.04, _c_ 0.08. + +_Habitat._--Central Pacific, Stations 263 to 274, depth 2350 to 2925 +fathoms. + + +38. _Podocyrtis lithoconus_, n. sp. (Pl. 72, fig. 3). + +Shell conical, thick-walled, smooth, with two slight strictures. Length of +the three joints = 2 : 3 : 6, breadth = 2 : 4 : 7. Cephalis hemispherical, +with a spindle-shaped horn of the some length. Pores subregular, circular, +two to four times as broad in the abdomen as in the thorax. Feet +triangular, shovel-shaped, nearly vertical, as long as the cephalis. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.06, _c_ 0.12; +breadth, _a_ 0.04, _b_ 0.08, _c_ 0.14. + +_Habitat._--Central Pacific, Station 270, depth 2925 fathoms. + + +39. _Podocyrtis ampla_, Ehrenberg. + + _Podocyrtis ampla_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 80, Taf. xvi. fig. 7. + +Shell conical, thick-walled, with distinct collar, but without lumbar +stricture. Length of the three joints = 1 : 4 : 5, breadth = 1 : 6 : 7. +Cephalis hemispherical, with a large conical horn, as long as the thorax. +Pores regular, circular, quincuncial, three times as broad in the rough +abdomen as in the smooth thorax. Feet very small, shovel-shaped, only as +long as the cephalis. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.08, _c_ 0.1; +breadth, _a_ 0.03, _b_ 0.12, _c_ 0.14. + +_Habitat._--North Atlantic (Florida); also fossil in Barbados. + + +40. _Podocyrtis nana_, Ehrenberg. + + _Podocyrtis nana_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, + p. 82, Taf. xvii. fig. 2. + +Shell conical, thorny, with two distinct strictures. Length of the three +joints = 1 : 3 : 3, breadth = 2 : 5 : 6. Cephalis hemispherical, with a +large cylindrical horn, nearly as long as the shell. Pores in the abdomen +irregular, roundish, two to four times as broad as the regular, circular, +quincuncial pores of the thorax. Feet very small, shovel shaped, scarcely +as long as the cephalis. + +_Dimensions._--Length of the three joints, _a_ 0.01, _b_ 0.03, _c_ 0.03; +breadth, _a_ 0.02, _b_ 0.05, _c_ 0.06. + +_Habitat._--South Atlantic, Station 335, depth 1425 fathoms; also fossil in +Barbados. + + +41. _Podocyrtis lyaea_, Haeckel. + + _Thyrsocyrtis lyaea_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 84, Taf. xii, fig. 3. + +Shell ovate, conical, with two deep strictures. Length of the three joints += 2 : 5 : 8, breadth = 3 : 8 : 9. Cephalis hemispherical, with a large +conical horn, which is spinulate, scaly, and as {1349}long as the abdomen. +Pores subregular, circular, two to four times as broad in the smooth +abdomen as in the spiny thorax. Feet very short and broad, shovel-shaped, +scarcely as long as the cephalis. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.05, _c_ 0.08; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.09. + +_Habitat._--Fossil in Barbados. + + +42. _Podocyrtis bromia_, Haeckel. + + _Thyrsocyrtis bromia_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 84, Taf. xii. fig. 2. + +Shell ovate, thorny, with two distinct strictures. Length of the three +joints = 2 : 5 : 5, breadth = 3 : 8 : 9. Cephalis subspherical, with a +large conical horn, which is half as long as the shell, and spirally +dentated in the distal half. Thorax conical, spinulate, with regular, +circular, quincuncial pores. Abdomen tuberculate, with a small number of +very large irregular pores. Feet short, shovel-shaped, nearly vertical, as +long as the cephalis. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.05, _c_ 0.05; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.09. + +_Habitat._--Fossil in Barbados. + + +43. _Podocyrtis sphaerogaster_, n. sp. + +Shell inversely ovate, with two deep strictures. Length of the three joints += 1 : 2 : 6, breadth = 2 : 4 : 7. Cephalis hemispherical, with a slender, +slightly bent horn, as long as the abdomen. Thorax hemispherical, +spinulate. Abdomen nearly spherical, with much constricted mouth. Pores +subregular, circular, hexagonally framed. Feet slender, cylindro-conical, +about as long as the shell, with outer convexity, distinctly convergent. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.12; +breadth, _a_ 0.04, _b_ 0.08, _c_ 0.14. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +44. _Podocyrtis tripus_, Haeckel. + + _Podocyrtis bicornis_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 80, Taf. xvi. fig. 8. + + ? _Podocyrtis dipus_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 83, Taf. xii. Fig. 11. + +Shell conical, rough, with two deep strictures. Length of the three joints += 1 : 2 : 4, breadth = 1 : 3 : 5. Cephalis subspherical, with a large, +oblique, conical horn (sometimes with a small accessory horn at its base). +Thorax hemispherical, with subregular, circular, small, quincuncial pores. +Abdomen campanulate, with a small number (about twenty) of very large, +irregular, polygonal pores. Feet conical, small, as long as the thorax, +slightly convergent or nearly vertical. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.08; +breadth, _a_ 0.03, _b_ 0.06, _c_ 0.1. + +_Habitat._--Fossil in Barbados. + + +{1350}45. _Podocyrtis triacantha_, Ehrenberg. + + _Podocyrtis triacantha_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, Taf. xiii. fig. 4. + +Shell conical, rough, with two distinct strictures. Length of the three +joints = 1 : 2 : 4, breadth = 2 : 4 : 6. Cephalis hemispherical, with a +very large conical horn, nearly as long as the whole shell. Thorax +campanulate, densely spinulate, with very small, regular, circular, +quincuncial pores. Thorax inflated, with very large, irregular, roundish, +pores (three to four in the course of its length), five to ten times as +broad as those of the thorax. Feet slender and thin, subcylindrical, as +long as the abdomen, divergent in the proximal half, convergent and curved +inwards in the distal half. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.08; +breadth, _a_ 0.04, _b_ 0.08, _c_ 0.12. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms; also fossil +in Barbados. + + + +Genus 593. _Thyrsocyrtis_,[210] Ehrenberg, 1847, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 54. + +_Definition._--#Theopilida# (vel Tricyrtida triradiata aperta) with three +branched terminal feet on the mouth of the abdomen, without lateral ribs or +wings. Apex with a horn, which usually bears lateral spines. + +The genus _Thyrsocyrtis_ differs from the preceding _Podocyrtis_, its +ancestral form, in the ramification of the three terminal feet, which in +the latter genus remain simple. + + +1. _Thyrsocyrtis rhizodon_, Ehrenberg. + + _Thyrsocyrtis rhizodon_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, Taf. xii. fig. 1. + +Shell slender, conical, smooth, with two distinct strictures. Length of the +three joints = 1 : 2 : 3, breadth = 1 : 3 : 4. Cephalis hemispherical, with +a large cylindrical horn, reaching half the length of the shell, and +papillate in the distal half. Pores nearly equal, regular, circular, +quincuncially disposed, small. Feet divergent, about half as long as the +shell, broadened and forked at the distal end. (The fork incision is often +much deeper, as in the figure given by Ehrenberg.) + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.06; +breadth, _a_ 0.03, _b_ 0.06, _c_ 0.08. + +_Habitat._--Fossil in Barbados. + + +2. _Thyrsocyrtis arborescens_, n. sp. (Pl. 68, fig. 9). + +Shell nearly ovate, thorny, with a deep collar, but without lumbar +stricture. Length of the three joints = 1 : 2 : 4, breadth = 2 : 3 : 4. +Cephalis hemispherical, with a stout scaly or branched horn, half as long +as the shell. Pores irregular, roundish, small, separated by spinulated +crests, of slightly different sizes. Feet divergent, cylindrical, and as +long as the thorax in the proximal half, {1351}irregularly branched or +arborescent in the distal half, with ten to thirty blunt, thickened or +papillate, terminal branches. + +_Dimensions._--Length of three joints, _a_ 0.02, _b_ 0.04, _c_ 0.08; +breadth, _a_ 0.04, _b_ 0.06, _c_ 0.08. + +_Habitat._--Central Pacific, Station 268, depth, 2900 fathoms. + + +3. _Thyrsocyrtis furcata_, n. sp. + +Shell ovate, thorny, with two slight strictures. Length of the three joints += 1 : 1 : 3, breadth = 1 : 2 : 3. Cephalis hemispherical, with a pyramidal +smooth horn of twice the length. Pores of the thorax and abdomen nearly +equal, regular, circular, quincuncial. Feet very broad, forked, about as +long as the abdomen, much divergent; the outer fork-branch as long as the +simple basal half of the foot, and twice as long as the inner or axial +branch. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.03, _c_ 0.09; +breadth, _a_ 0.04, _b_ 0.06, _c_ 0.09. + +_Habitat._--Tropical Atlantic, Station 338, depth 1990 fathoms. + + +4. _Thyrsocyrtis rhizopus_, Haeckel. + + _Podocyrtis rhizodon_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 83, Taf. xv. fig. 2. + +Shell pear-shaped, smooth, with two slight strictures. Length of the three +joints = 1 : 2 : 4, breadth = 1 : 3 : 5. Cephalis ovate, with a stout, +sword-shaped horn of the same length. Pores regular, circular, twice as +broad in the inflated abdomen as in the truncate, conical thorax. Feet +cylindrical, parallel, vertical, straight, divided at the distal end into +two short fork-branches. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.08; +breadth, _a_ 0.02, _b_ 0.06, _c_ 0.1. + +_Habitat._--Fossil in Barbados. + + +5. _Thyrsocyrtis rhizopodium_, n. sp. (Pl. 68, fig. 8). + +Shell campanulate-conical, with deep collar, but without lumbar stricture. +Length of the three joints = 3 : 4 : 10, breadth = 4 : 10 : 15. Cephalis +subspherical, with a small conical horn of the same length. Pores regular, +circular, quincuncial, three to four times as large in the inflated abdomen +as in the truncate, conical thorax. Feet cylindrical, slightly divergent, +about as long as the abdomen, S-shaped, bent outwards, irregularly branched +in the distal half, with tuberculate terminal branches. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.04, _c_ 0.1; +breadth, _a_ 0.04, _b_ 0.1, _c_ 0.15. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +6. _Thyrsocyrtis radicata_, Haeckel. + + _Podocyrtis radicata_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 82, Taf. xiii. fig. 5. + +Shell campanulate-conical, with two distinct strictures, length of the +three joints = 1 : 2 : 4, breadth = 1 : 4 : 6. Cephalis subspherical, with +a small conical horn of half the length. Pores regular, {1352}circular, +quincuncial, four to five times as broad in the inflated, rough abdomen as +in the campanulate, smooth thorax. Feet cylindrical, nearly as long as the +whole shell, S-shaped, bent outwards, dilated and hand-shaped at the distal +end, divided by three to five incisions in some irregular finger-like +branches. + +_Dimensions_.--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.08; +breadth _a_ 0.03, _b_ 0.08, _c_ 0.12. + +_Habitat._--Fossil in Barbados. + + +7. _Thyrsocyrtis trifida_, n. sp. + +Shell campanulate-conical, thorny, with two slight strictures. Length of +the three joints = 1 : 2 : 3, breadth = 1 : 3 : 5. Cephalis subspherical, +with a short pyramidal horn of the same length. Pores regular, circular, +hexagonally framed, twice as broad in the inflated spiny abdomen as in the +rough, campanulate thorax. Feet very large, as long as the shell, +cylindrical in the proximal simple half, in the distal half broadened and +cleft into three large, irregularly lobed branches, two shorter lateral, +and one longer abaxial branch; the latter forms the prolongation of the +proximal half. The outer straight edges of the three diverging feet +correspond to the edges of a three-sided pyramid. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.05, _c_ 0.09; +breadth, _a_ 0.03, _b_ 0.09, _c_ 0.15. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + + +Genus 594. _Dictyopodium_,[211] Ehrenberg, 1847, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 54. + +_Definition._--#Theopilida# (vel Tricyrtida triradiata aperta) with three +latticed terminal feet on the mouth of the abdomen, without lateral ribs or +wings. Apex with a horn. + +The genus _Dictyopodium_ differs from the two preceding ancestral genera in +the fenestration of the three terminal feet, which in _Podocyrtis_ are +simple, in _Thyrsocyrtis_ branched, but not latticed. + + +1. _Dictyopodium eurylophus_, Ehrenberg. + + _Dictyopodium eurylophus_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 68, Taf. xix. fig. 4. + +Shell campanulate-conical, thorny, with two deep strictures. Length of the +three joints = 1 : 2 : 3, breadth = 1 : 3 : 4. Cephalis hemispherical, with +a stout angular horn of twice the length, which at the apex is broadened +and divided into some spines. Pores in the hemispherical thorax and in the +truncate, conical abdomen of nearly equal size, small, subregular, circular +(in the {1353}abdomen sometimes more irregular and unequal). Feet as long +as the abdomen, arising from it with triangular base, diverging, +fenestrated throughout the entire length. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.06, _c_ 0.08; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.1. + +_Habitat._--Central Pacific, Station 263, depth 2650 fathoms; fossil in +Barbados. + + +2. _Dictyopodium oxylophus_, Ehrenberg. + + _Dictyopodium oxylophus_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 68, Taf. xix. fig. 5. + +Shell subconical, smooth, with two slight strictures. Length of the three +joints = 2 : 5 : 7, breadth = 3 : 8 : 10. Cephalis subspherical, with a +small, conical, smooth horn of the same length. Pores irregular, polygonal, +roundish, slightly larger in the abdomen than in the thorax. Feet as long +as the thorax, arising from it with triangular base, diverging, fenestrated +throughout the entire length. (The figures of this and the preceding +species given by Ehrenberg are incomplete, having been drawn from spoiled +specimens. In perfect specimens all the three feet are present and diverge +in both species in the direction of the conical outline. The main +difference between the two species is connected with the pores, which in +_Dictyopodium oxylophus_ are larger and more irregular, the two strictures +are here not so deep.) + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.05, _c_ 0.07; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.1. + +_Habitat._--Fossil in Barbados. + + +3. _Dictyopodium scaphopodium_, n. sp. (Pl. 73, fig. 8). + +Shell campanulate, conical, with two deep strictures. Length of the three +joints = 1 : 2 : 6, breadth = 1 : 4 : 8. Cephalis hemispherical, with a +conical, smooth horn of twice the length. Thorax hemispherical, rough, with +small, regular, circular pores. Abdomen inflated and papillate, with very +large, polygonal or roundish pores (eight to ten times as broad as the +thoracic pores). Feet divergent, nearly as long as the shell, S-shaped, +bent outwards, solid and cylindrical in the proximal half, shovel-shaped +and fenestrated in the distal half. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.12; +breadth, _a_ 0.025, _b_ 0.08, _c_ 0.16. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +4. _Dictyopodium cothurnatum_, Haeckel. + + _Podocyrtis cothurnata_, Ehrenberg, 1854, Mikrogeol., Taf. xxxvi. fig. B. + 21; Abhandl. d. k. Akad. d. Wiss. Berlin, 1875, p. 82, Taf. xiv. fig. 1. + + _Anthocyrtis cothurnata_, Haeckel, 1862, Monogr. d. Radiol., p. 310. + +Shell subconical, rough, with two deep strictures. Length of the three +joints = 1 : 2 : 3, breadth = 1 : 3 : 5. Cephalis hemispherical, with a +very large cylindrical, vertical horn, about as long as the whole shell. +Thorax conical, rough, with small, regular, circular pores. Abdomen +inflated, with very large, roundish pores (four to five in the course of +its length), six to eight times {1354}as large as the thoracic pores. Feet +nearly vertical, only slightly divergent, S-shaped, bent, as long as the +abdomen, cylindrical; at the distal end shovel-shaped and fenestrated +(often much more than in Ehrenberg's figure). + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.06, _c_ 0.1; +breadth, _a_ 0.03, _b_ 0.09, _c_ 0.15. + +_Habitat._--Fossil in Barbados. + + +5. _Dictyopodium thyrsolophus_, n. sp. (Pl. 73, fig. 7). + +Shell subconical, rough, with two slight strictures. Length of the three +joints = 1 : 2 : 4, breadth = 1 : 3 : 6. Cephalis hemispherical, with an +elegant horn, which is half as long as the shell, spindle-shaped and scaly +on the distal third. Thorax hemispherical, with small, regular, circular +pores. Abdomen inflated, papillate, with regular, circular pores, three +times as large as the thoracic pores (five to six in the course of its +length). Feet slightly divergent, cylindrical, about as long as the shell, +shovel-shaped and fenestrated (with a prominent middle rib) at the distal +end. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.06, _c_ 0.12; +breadth, _a_ 0.04, _b_ 0.1, _c_ 0.18. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + + +Subfamily 2. THEOPERIDA, Haeckel, 1881, Prodromus, p. 436. + +_Definition._--#Podocyrtida# with the basal mouth of the shell fenestrated +(vel Tricyrtida triradiata clausa). + + + +Genus 595. _Lithornithium_,[212] Ehrenberg, 1847, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 54. + +_Definition._--#Theoperida# (vel Tricyrtida triradiata clausa) with three +solid lateral wings on the thorax. + +The genus _Lithornithium_ has an ovate or spindle-shaped shell, with two +distinct strictures, and tapering towards both poles. The abdomen is +simple, whilst the cephalis bears an apical horn, and the thorax three +free, lateral, solid, divergent wings. It may be derived from _Pterocorys_ +by development of a terminal lattice-plate closing the mouth. + + +1. _Lithornithium ciconia_, n. sp. (Pl. 67, fig. 3). + +Shell nearly spindle-shaped, with two indistinct strictures. Length of the +three joints = 1 : 2 : 4, breadth = 1 : 3 : 3. Cephalis ovate, with a large +pyramidal spine of twice the length. Thorax three-sided pyramidal with +three pyramidal wings of the same length, the broad triangular bases of +which occupy the whole length of the thoracic edges. Abdomen inversely +ovate (in the {1355}figured specimen broken off, in another specimen, found +afterwards, completely closed at the distal end). Pores very small, +regular, circular, of equal size. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.08; +breadth, _a_ 0.02, _b_ 0.06, _c_ 0.06. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +2. _Lithornithium falco_, n. sp. (Pl. 67, fig. 1). + +Shell nearly ovate, with two sharp strictures. Length of the three joints = +1 : 3 : 4, breadth = 1 : 4 : 3. Cephalis hemispherical, with a conical +spine of the same length. Thorax subspherical, with three conical wings of +half the length, little curved, arising with broad triangular base from the +upper half of the thorax. Abdomen inversely conical. Pores irregular, +roundish, of different sizes. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.07; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.06. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +3. _Lithornithium trochilus_, n. sp. (Pl. 67, fig. 4). + +Shell nearly spindle-shaped, with two deep strictures. Length of the three +joints = 1 : 2 : 3, breadth = 1 : 3 : 2. Cephalis hemispherical, with a +thin curved horn of the same length. Cephalis subovate, with three thin +curved wings of half the length, arising with broad base from its upper +half. Abdomen ovate. Pores subregular, circular, of slightly different +sizes. + +_Dimensions._--Length of the three joints, _a_ 0.015, _b_ 0.05, _c_ 0.06; +breadth, _a_ 0.02, _b_ 0.05, _c_ 0.04. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +4. _Lithornithium foveolatum_, Ehrenberg. + + _Lithornithium foveolatum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 78, Taf. iv. fig. 7. + +Shell subovate, with two distinct strictures. Length of the three joints = +2 : 4 : 3, breadth = 3 : 5 : 4. Cephalis hemispherical, with a short +conical spine of the same length. Thorax subspherical, with three broad +triangular wings of half the length arising from its lower half. Abdomen +subconical. Pores small, regular, circular, of nearly equal size. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.03; +breadth, _a_ 0.03, _b_ 0.05, _c_ 0.04. + +_Habitat._--Fossil in Barbados. + + +5. _Lithornithium fringilla_, n. sp. (Pl. 67, fig. 2). + +Shell ovate, with two slight strictures. Length of the three joints = +4 : 7 : 4, breadth = 3 : 7 : 5. Cephalis ovate, with a pyramidal spine of +the same length Thorax subconical, with three stout {1356}conical, curved +wings of half the length, arising from its lower third (immediately above +the girdle). Abdomen inversely campanulate. Pores subregular, circular, of +equal size. + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.07, _c_ 0.04; +breadth, _a_ 0.03, _b_ 0.07, _c_ 0.05. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +6. _Lithornithium hirundo_, Ehrenberg. + + _Lithocampe hirundo_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 65. + + _Lithornithium hirundo_, Ehrenberg, 1854, Mikrogeol., Taf. xix. fig. 53. + +Shell nearly ovate, with two deep strictures. Length of the three joints = +2 : 6 : 4, breadth = 2 : 7 : 5. Cephalis hemispherical, with an oblique, +conical horn of twice the length. Thorax hemispherical, with three long, +angular, little divergent wings of twice the length, which are S-shaped, +curved, and arise from its lower third, immediately above the girdle. +Abdomen inversely conical. Pores irregular, roundish, of different sizes. +In the figure of Ehrenberg the abdomen is broken off; in a specimen from +Caltanisetta, with somewhat shorter and broader wings, I found it complete. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.04; +breadth, _a_ 0.02, _b_ 0.07, _c_ 0.05. + +_Habitat._--Fossil in Tertiary rocks of the Mediterranean (Aegina, Greece; +Caltanisetta, Sicily). + + + +Genus 596. _Sethornithium_,[213] Haeckel, 1881, Prodromus, p. 436. + +_Definition._--#Theoperida# (vel Tricyrtida triradiata clausa) with three +latticed lateral wings on the thorax. + +The genus _Sethornithium_ differs from the preceding _Lithornithium_, its +ancestral form, only in the fenestration of the three thoracic wings, and +bears therefore to it the same relation that _Dictyoceras_ exhibits to +_Pterocorys_. + + +1. _Sethornithium dictyopterum_, n. sp. Pl. 68, fig. 14. + +Shell ovate, with two slight strictures. Length of the three joints = +2 : 4 : 3, breadth = 1 : 5 : 4. Cephalis ovate, with a pyramidal horn of +twice the length. From the middle part of the thorax arise three broad, +triangular, latticed wings of about the same length, the distal end of each +of which is curved downwards. Abdomen inversely conical. Pores regular, +circular. (Similar to _Lithornithium fringilla_, Pl. 67, fig. 2, but with +much larger wings, which in the greater part are fenestrated.) + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.08, _c_ 0.06; +breadth, _a_ 0.02, _b_ 0.1, _c_ 0.08. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +{1357}Genus 597. _Theopera_,[214] Haeckel, 1881, Prodromus, p. 436. + +_Definition._--#Theoperida# (vel Tricyrtida triradiata clausa) with three +lateral wings, beginning from the sides of the thorax and prolonged into +the sides of the abdomen. + +The genus _Theopera_ differs from the two preceding genera in the greater +extension of the three lateral wings, which are prolonged from their +original base, the thorax, into the inversely conical abdomen. It has +therefore an intermediate position between the preceding and the following +genera. It differs from the similar _Pterocanium_ and _Theopodium_ in the +closure of the constricted and fenestrated mouth. + + +1. _Theopera prismatica_, n. sp. (Pl. 67, fig. 7). + + _Rhopalocanium prismaticum_, Haeckel, 1879, Atlas, pl. lxvii. fig. 7. + +Shell three-sided prismatic, with three broad and long hyaline wings, which +are prolonged from the collar stricture almost to the basal end, with three +parallel edges. Length of the three joints = 2 : 8 : 10, breadth = +3 : 9 : 8. Cephalis hemispherical, with a conical horn of the same length. +Thorax subspherical; abdomen inversely ovate; pores of both small, regular, +circular, of equal size. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.08, _c_ 0.1; +breadth, _a_ 0.03, _b_ 0.09, _c_ 0.08. + +_Habitat._--South Atlantic, Station 332. depth 2200 fathoms. + + +2. _Theopera pyramis_, Haeckel. + + _Rhopalocanium_ sp., Bury, 1862, Polycystins of Barbados, pl. xvii. fig. + 8. + +Shell three-sided pyramidal, with three broad and long hyaline wings, which +are prolonged from the collar stricture almost to the basal end, with three +diverging edges. Length of the three joints = 3 : 8 : 11, breadth = +4 : 8 : 9. Cephalis subspherical, with a conical horn of the same length. +Thorax hemispherical; abdomen inversely campanulate. Pores in the abdomen +twice to three times as broad as in the thorax, subregular, circular. +Differs from the preceding species mainly in the broader pyramidal form and +the divergence of the wings. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.08, _c_ 0.11; +breadth, _a_ 0.04, _b_ 0.08, _c_ 0.09. + +_Habitat._--Fossil in Barbados. + + +3. _Theopera fusiformis_ (Pl. 67, fig. 5). + +Shell nearly spindle-shaped, rough, with two slight strictures. Length of +the three joints = 2 : 3 : 6, breadth = 2 : 5 : 4. Cephalis hemispherical, +large, with an oblique conical horn of the same length. Thorax +hemispherical; abdomen inversely conical. Pores irregular, roundish, of +very {1358}different sizes. Three wings short, broad, diverging, +triangular, and striated, embracing at the base the lumbar stricture, the +lower third of the thorax and the upper third of the abdomen. + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.06, _c_ 0.12; +breadth, _a_ 0.045, _b_ 0.1, _c_ 0.08. + +_Habitat._--Central Pacific, Stations 263 to 274, depth 2350 to 2925 +fathoms. + + +4. _Theopera luscinia_, Haeckel. + + _Lithornithium luscinia_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 78, Taf. iv. fig. 9. + +Shell slenderly ovate, with distinct collar, but indistinct lumbar +strictures. Length of the three joints = 1 : 3 : 6, breadth = 1 : 5 : 5. +Cephalis hemispherical, with a slender cylindrical horn of three times the +length, bearing a spindle-shaped spinulate top (like a fir-cone). Pores +subregular, circular, twice as broad in the abdomen as in the thorax. Three +wings arising with broad triangular base, embracing the lower third of the +thorax and the upper third of the abdomen, prolonged into three slender +diverging spines, as long as the shell. + +_Dimensions._--Length of the three joints _a_ 0.015, _b_ 0.05, _c_ 0.1; +breadth, _a_ 0.02, _b_ 0.07, _c_ 0.07. + +_Habitat._--Fossil in Barbados. + + +5. _Theopera chytropus_, n. sp. (Pl. 67, fig. 6). + +Shell slender, ovate, with distinct collar, but indistinct lumbar +stricture. Length of the three joints = 1 : 2 : 5, breadth = 1 : 3 : 3. +Cephalis hemispherical, with a conical horn of the same length. Pores in +the thorax and abdomen of similar shape, irregular, roundish. Three wings +with broad triangular base attached at the upper half of the shell, in the +lower half free, diverging, with a spinulate knob at the distal end. + +_Dimensions._--Length of the three joints, _a_ 0.025, _b_ 0.06, _c_ 0.15; +breadth, _a_ 0.03, _b_ 0.09, _c_ 0.09. + +_Habitat._--Central Pacific, Stations 265 to 268, depth 2700 to 2900 +fathoms. + + +6. _Theopera cortina_, n. sp. (Pl. 67, fig. 8). + +Shell slender, ovate, with distinct collar, but indistinct lumbar +stricture. Length of the three joints = 1 : 2 : 6, breadth 1 : 4 : 4. +Cephalis subspherical, with an elegant pyramidal horn of three times the +length, bearing an ovate, spinulate knob. Pores subregular, circular, two +or three times as large in the abdomen as in the thorax. The three wings +are slightly elevated small ribs on the thorax, arise with broad, +triangular, striated bases in the upper half of the abdomen, and are +prolonged into three slender diverging feet, which are as long as the +shell, and bear a spinulate, ovate knob at the distal end. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.05, _c_ 0.13; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.08. + +_Habitat._--Tropical Atlantic, Station 338, depth 1990 fathoms. + + + +{1359}Genus 598. _Rhopalocanium_,[215] Ehrenberg, 1847, Monatsber. d. k. +preuss. Akad. d. Wiss. Berlin, p. 54. + +_Definition._--#Theoperida# (vel Tricyrtida triradiata clausa) with three +lateral wings on the sides of the inversely conical abdomen, which bears no +vertical terminal horn on the basal apex. + +The genus _Rhopalocanium_, and the closely allied _Rhopalatractus_ which +follows, differ from the preceding _Theopera_, their probable ancestral +form, in the origin of the three lateral wings from the inversely conical +abdomen, the thorax bearing no wings. The upper part of the wing bases, +which arose formerly from the thorax, is here reduced and lost. + + +1. _Rhopalocanium lasanum_, n. sp. (Pl. 67, fig. 10). + +Shell subovate, with two distinct strictures. Length of the three joints = +1 : 2 : 3, breadth = 1 : 3 : 4. Cephalis hemispherical, with a conical, +dimpled horn of twice the length. Thorax subconical, abdomen campanulate, +both with irregular, circular pores. Three wings cylindrical, divergent, +about as long as the shell, striated, with an ovate, dimpled knob at the +distal end, their broad triangular base being attached to the upper half of +the abdomen. (Form rather variable.) + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.07, _c_ 0.09; +breadth, _a_ 0.03, _b_ 0.09, _c_ 0.12. + +_Habitat._--Central Pacific, Stations 263 to 268, depth 2650 to 3000 +fathoms. + + +2. _Rhopalocanium ornatum_, Ehrenberg. + + _Rhopalocanium ornatum_, Ehrenberg, 1854, Mikrogeol., Taf. xxxvi. fig. 9; + Abhandl. d. k. Akad. d. Wiss. Berlin, 1875, p. 82, Taf. xvii. fig. 8. + +Shell nearly spindle-shaped, with two distinct strictures. Length of the +three joints = 1 : 3 : 6, breadth = 1 : 4 : 3. Cephalis hemispherical, with +a stout, cylindrical horn of twice the length, bearing a dimpled cone. +Thorax ovate, campanulate. Abdomen inversely conical. Pores subregular, +circular, twice as large in the thorax as in the abdomen. Three wings +compressed, slender, divergent, slightly longer than the abdomen, bearing +an ovate, dimpled cone at their distal end, with the broad, triangular, +striated base attached to the upper third of the abdomen. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.12; +breadth, _a_ 0.025, _b_ 0.08, _c_ 0.07. + +_Habitat._--Fossil in Barbados. + + +3. _Rhopalocanium cortinium_, n. sp. + +Shell slender, ovate, nearly of the same form as, and with similar +fenestration to that of _Theopera cortina_, (Pl. 67, fig. 8). It differs +from the latter mainly by the absence of the three thoracic ribs, +characteristic of _Theopera_. Length of the three joints = 1 : 2 : 6, +breadth = 1 : 4 : 4. The {1360}three wings arise by a broad, triangular, +striated base from the upper half of the abdomen, below the lumbar +stricture. The cephalic horn and the three divergent wings are shorter, and +at the distal end not so much thickened as in _Theopera cortina_. + +_Dimensions._--Length of the three joints, _a_ 0.025, _b_ 0.045, _c_ 0.12; +breadth, _a_ 0.03, _b_ 0.07, _c_ 0.08. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + +4. _Rhopalocanium pythia_, n. sp. + + _Rhopalocanium ornatum_, Bury, 1862, Polycystins of Barbados, pl. vi. + fig. 1. + +Shell nearly ovate, with two deep strictures. Length of the three joints = +1 : 4 : 8, breadth = 1 : 4 : 4. Cephalis subspherical, with a conical horn +of three times the length. Thorax inflated, abdomen inversely campanulate +and prolonged into a short, conical, latticed tube. Pores subregular, +circular. Three wings slender, as long as the abdomen, arising by a broader +base from the uppermost part of the abdomen, their thickened end being +curved inwards. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.07, _c_ 0.15; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.07. + +_Habitat._--Fossil in Barbados. + + +5. _Rhopalocanium delphicum_, n. sp. (Pl. 67, fig. 9). + +Shell nearly spindle-shaped, with two deep strictures. Length of the three +joints = 1 : 2 : 4, breadth = 1 : 3 : 3. Cephalis hemispherical, with a +slender, conical, curved horn, as long as the hemispherical thorax. Abdomen +inversely campanulate, prolonged into a short, conical, latticed tube. +Pores subregular, circular. Three wings arising by a narrow base from the +uppermost part of the abdomen, slender, cylindrical, S-shaped, curved, +divergent, with a thick scaly appendix like a fir-cone at the distal end. + +_Dimensions._--Length of the three joints, _a_ 0.025, _b_ 0.07, _c_ 0.14; +breadth, _a_ 0.03, _b_ 0.09, _c_ 0.08. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + + +Genus 599. _Rhopalatractus_,[216] Haeckel, 1881, Prodromus, p. 437. + +_Definition._--#Theoperida# (vel Tricyrtida triradiata clausa) with three +lateral wings on the sides of the inversely conical abdomen, which bears a +vertical terminal horn on the basal apex. + +The genus _Rhopalatractus_, one of the most remarkable forms of Tricyrtida, +differs from the preceding _Rhopalocanium_, its ancestral form, in the +production of a vertical, basal horn, which descends from the basal apex of +the inversely conical abdomen, and is opposed to the upper apical horn of +the cephalis. The shell becomes here, therefore, exquisitely +spindle-shaped. + + +{1361}1. _Rhopalatractus pentacanthus_, n. sp. (Pl. 68, fig. 11). + +Shell very thick-walled, with two sharp strictures. Length of the three +joints = 1 : 6 : 8, breadth = 1 : 6 : 7. Cephalis hemispherical, with +conical cavity, and a conical horn of twice the length. Thorax +subspherical, separated from the abdomen by a deep lumbar stricture, with +small, regular, circular, hexagonally-framed pores. Abdomen three-sided +prismatic, with three strong, prominent, wing-shaped edges, which are +slightly divergent towards the base, and prolonged into three pyramidal +feet about as long as the thorax. Pores of the abdomen disposed in +longitudinal rows, which are separated by denticulate crests. Abdominal +base inversely pyramidal, and prolonged into a very large, cylindrical, +basal, axial spine, nearly as long as the whole shell. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.12, _c_ 0.15; +breadth, _a_ 0.03, _b_ 0.11, _c_ 0.14. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +2. _Rhopalatractus foveolatus_, n. sp. (Pl. 68, fig. 10). + +Shell slenderly ovate, thick-walled, with rough, dimpled surface. Length of +the three joints = 1 : 3 : 5, breadth = 2 : 4 : 4. Cephalis hemispherical, +with spherical cavity, and a thick, conical spine of the same length. +Thorax subspherical, with subregular, circular pores. Abdomen inversely +conical, with larger, irregular, roundish pores, prolonged at the distal +end into a cylindrical, axial, basal spine of about half its length. From +the middle part of the abdomen arise three lateral, conical feet, which are +slightly curved and divergent downwardly, scarcely as long as the basal +spine. All five spines are dimpled. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.1; +breadth _a_ 0.04, _b_ 0.08, _c_ 0.08. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +3. _Rhopalatractus fusiformis_, n. sp. + +Shell slender, spindle-shaped, nearly of the same form as in the preceding +species. Length of the three joints = 1 : 2 : 6, breadth = 1 : 2 : 2. +Cephalis subspherical, with a cylindrical horn three times the length. +Pores subregular, circular, of equal breadth in the thorax and in the +abdomen, which is prolonged into a cylindrical, axial, basal spine of the +same length. From the upper third of the abdomen arise, from a broad +triangular base, three conical wings of half the length, divergent and +slightly curved inwards. + +_Dimensions._--Length of the three joints, _a_ 0.025, _b_ 0.05, _c_ 0.15; +breadth, _a_ 0.03, _b_ 0.06, _c_ 0.06. + +_Habitat._--Central Pacific, Station 263, depth 2650 fathoms. + + +4. _Rhopalatractus fenestratus_, n. sp. (Pl. 68, fig. 12). + + _Dictyatractus fenestratus_, Haeckel, 1881, Prodromus et Atlas. + +Shell nearly spindle-shaped, with two distinct strictures. Length of the +three joints = 1 : 3 : 6, breadth = 1 : 4 : 4. Cephalis hemispherical, with +a large, club-shaped horn, nearly as long as the abdomen, sulcated by +longitudinal ribs, which are elegantly denticulate in the distal half. +Thorax {1362}subspherical. Abdomen subovate, prolonged into a pyramidal, +axial, basal spine, half as long as the thorax. Pores subregular, circular. +From the upper half of the abdomen arise three stout, lateral, diverged +wings of about the same length, which are curved inwards and fenestrated +both at the broad triangular base and at the thickened, three-edged distal +end. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.12; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.08. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + + +Genus 600. _Lithochytris_,[217] Ehrenberg, 1847, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 54. + +_Definition._--#Theoperida# (vel Tricyrtida triradiata clausa) with a +three-sided pyramidal abdomen, the triangular base of which is prolonged at +the three corners into three terminal feet. + +The genus _Lithochytris_ differs from all the other Theoperida in the +absence of lateral wings and the possession of three divergent, terminal +feet, which arise from the three corners of the three-sided pyramidal +abdomen. It repeats, therefore, among the Tricyrtida, that characteristic +formation which _Sethochytris_ and _Tetrahedrina_ represent among the +Dicyrtida. Some species may be derived from _Pterocanium_, other species +from _Podocyrtis_, by the development of a lattice-plate closing the +terminal mouth. + + + +Subgenus 1. _Lithochytrodes_, Haeckel. + +Three feet of the abdomen solid, not fenestrated, representing external +apophyses of the triangular shell-base. + + +1. _Lithochytris cortina_, n. sp. (Pl. 67, fig. 12). + +Shell three-sided pyramidal, without external strictures, but with two +internal girdles. Length of the three joints = 2 : 2 : 5, breadth = +3 : 4 : 6. Cephalis large, truncate-pyramidal, with nine deep divergent +ribs (and nine longitudinal rows of pores between them), and with a stout +pyramidal horn of half the length. The three prominent edges of the thorax +and abdomen are prolonged over the base of the pyramid into three very +stout, solid, subovate feet, about as long as the thorax. + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.04, _c_ 0.1; +breadth, _a_ 0.06, _b_ 0.08, a 0.12. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +2. _Lithochytris pyriformis_, n. sp. (Pl. 67, fig. 13). + +Shell pyramidal, nearly pear-shaped, with two distinct strictures. Length +of the three joints = 1 : 1 : 3, breadth = 1 : 2 : 3. Cephalis large, +pear-shaped, with a short pyramidal horn of half the {1363}length. Thorax +and abdomen rounded, without prominent edges. Three basal feet pyramidal, +solid, nearly vertical, as long as the thorax. Pores irregular, roundish, +in the abdomen large, twice to three times as broad as in the thorax. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.03, _c_ 0.08; +breadth, _a_ 0.04, _b_ 0.06, _c_ 0.09. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms. + + +3. _Lithochytris tripodium_, Ehrenberg. + + _Lithochytris tripodium_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 76, Taf. iv. fig. 11. + +Shell pyramidal, nearly pear-shaped, with two distinct strictures. Length +of the three joints = 1 : 2 : 4, breadth = 1 : 2 : 5. Cephalis with a horn +of the same length, conical. Thorax and abdomen rounded, without prominent +edges. Three basal feet conical, solid, strongly divergent, shorter than +the thorax. Pores subregular, circular, twice as broad in the abdomen as in +the thorax. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.08; +breadth, _a_ 0.03, _b_ 0.05, _c_ 0.1. + +_Habitat._--Fossil in Barbados. + + + +Subgenus 2. _Lithochytridium_, Haeckel. + +_Definition._--Three feet of the abdomen hollow and fenestrated, +representing direct protuberances or corner prolongations of the triangular +shell-base. + + +4. _Lithochytris galeata_, n. sp. (Pl. 67, fig. 16). + +Shell pyramidal, with two sharp strictures. Length of the three joints = +1 : 1 : 4, breadth = 1 : 2 : 4. Cephalis subspherical, with an oblique +pyramidal horn of the same length. Thorax somewhat larger. Abdomen +inflated, with three sharp, prominent edges, which are prolonged over the +shell-base into three pyramidal, hollow, and fenestrated feet, longer than +the thorax. Pores subregular, circular, twice as broad in the abdomen as in +the thorax. + +_Dimensions._--Length of the three joints, _a_ 0.025, _b_ 0.025, _c_ 0.1; +breadth, _a_ 0.025, _b_ 0.05, _c_ 0.1. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +5. _Lithochytris pileata_, Ehrenberg. + + _Lithochytris pileata_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 76, Taf. v. fig. 3. + +Shell three-sided pyramidal, with deep collar, but indistinct lumbar +stricture. Length of the three joints = 2 : 2 : 9, breadth = 3 : 5 : 10. +Cephalis with a conical horn of the same length, pear-shaped. Thorax very +short and broad. Abdomen inflated, with three sharp, prominent edges, which +{1364}are prolonged over the shell-base into three pyramidal, hollow and +fenestrated feet, the lower edge of which is horizontal. Pores regular, +circular, of equal size in the thorax and abdomen. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.02, _c_ 0.09; +breadth, _a_ 0.03, _b_ 0.05, _c_ 0.1. + +_Habitat._--Fossil in Barbados. + + +6. _Lithochytris lucerna_, n. sp. (Pl. 67, fig. 14). + +Shell three-sided pyramidal, with two indistinct strictures. Length of the +three joints = 1 : 2 : 5, breadth = 2 : 3 : 8. Cephalis small, with a horn +of the same length, conical. Thorax with subspherical cavity. Abdomen with +three rounded, prominent edges, which are prolonged over the shell-base +into three conical, hollow, and fenestrated feet, twice as long as the +thorax, with a thick, pyramidal, terminal spine. Pores subregular, +circular, of equal size in the thorax and abdomen. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.1; +breadth, _a_ 0.04, _b_ 0.06, _c_ 0.16. + +_Habitat._--South Pacific, Station 297, depth 1775 fathoms. + + +7. _Lithochytris lanterna_, n. sp. (Pl. 67, fig. 11). + +Shell three-sided pyramidal, with two distinct strictures. Length of the +three joints = 1 : 2 : 4, breadth = 1 : 3 : 6. Cephalis small, with a +pyramidal slender horn of twice the length. Thorax with subspherical +cavity. Abdomen with three sharp prominent edges, which are prolonged over +the convex shell-base into three slender, prismatic, hollow, fenestrated +feet, strongly divergent, twice as long as the thorax (seen in fig. 11 from +the vaulted base). Pores circular, twice as broad in the abdomen as in the +thorax. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.08; +breadth, _a_ 0.02, _b_ 0.06, _c_ 0.12. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +8. _Lithochytris pyramidalis_, Ehrenberg. + + _Lithochytris pyramidalis_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 76, Taf. v. fig. 1. + +Shell three-sided pyramidal, without external strictures, but with two +internal transverse girdles. Length of the three joints = 1 : 2 : 6, +breadth = 2 : 4 : 8. Cephalis with a short horn of half the length, +conical. Cavity of the thorax subspherical. Abdomen with three rounded +edges, prolonged over the concave base into three pyramidal, hollow, and +fenestrated feet, twice as long as the thorax. Pores large, irregular, +roundish. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.12; +breadth, _a_ 0.04, _b_ 0.08, _c_ 0.16. + +_Habitat._--Central Pacific, Stations 265 to 268, depth 2700 to 2900 +fathoms; fossil in Barbados. + + +9. _Lithochytris pteropus_, n. sp. (Pl. 67, fig. 15). + +Shell three-sided pyramidal, with two indistinct strictures, but with two +broad, internal girdles. Length of the three joints = 2 : 2 : 6, breadth = +2 : 3 : 9. Cephalis with a small horn of half the {1365}length, +pear-shaped. Thorax broader than long. Abdomen with three prominent, +rounded edges, prolonged over the concave base into three conical, hollow, +and fenestrated feet, twice as long as the thorax. Pores small, circular, +irregular, in longitudinal series along the edges. + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.04, _c_ 0.12; +breadth, _a_ 0.04, _b_ 0.06, _c_ 0.18. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +10. _Lithochytris vespertilio_, Ehrenberg. + + _Lithochytris vespertilio_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 76, Taf. iv. fig. 10. + +Shell three-sided pyramidal, with two indistinct strictures. Length of the +three joints = 1 : 2 : 5, breadth = 2 : 3 : 10. Cephalis with a short horn +of half the length, conical. Thorax inflated. Abdomen without prominent +edges, divided in the lower half into three large, conical, hollow, and +fenestrated feet, twice as long as the thorax. Pores small, irregular, +roundish. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.1; +breadth, _a_ 0.04, _b_ 0.06, _c_ 0.2. + +_Habitat._--Fossil in Barbados. + + + +Family LXVI. #PHORMOCYRTIDA#, n. fam. + + _Theophormida et Theophaenida_, Haeckel, 1881, Prodromus, pp. 436, 437. + +_Definition._--#Tricyrtida# multiradiata. (#Cyrtoidea# with a three-jointed +shell, divided by two transverse constrictions into cephalis, thorax, and +abdomen, with numerous, four to nine or more, radial apophyses.) + +The family #Phormocyrtida#, composed of the Theophormida and Theophaenida +of my Prodromus, comprises those #Cyrtoidea# in which the lattice-shell is +three-jointed, and bears numerous radial appendages (usually six or nine, +sometimes more, rarely less, four or five). The two subfamilies differ in +the shape of the terminal mouth, which is in the Theophormida a simple wide +opening, in the Theophaenida closed by a lattice-plate. The phylogenetic +origin of the Phormocyrtida may be found either in the Podocyrtida or in +the Anthocyrtida; they may be derived either from the former by +interpolation of interradial, secondary apophyses between the three primary +perradial apophyses; or from the latter by development of an abdomen. + +The radial apophyses are originally radial ribs, which arise from the base +of the cephalis on the collar stricture, run along the thorax and abdomen, +and are often prolonged into terminal feet. Whilst in some forms the radial +ribs are completely preserved in both joints, they are in other forms only +partly visible (in the abdomen), and very often only their free terminal +prolongations are preserved in the form of a corona of feet around the +mouth of the thorax. This corona is either simple or double. Sometimes also +a corona is developed on the lumbar stricture, between the thorax and +abdomen. + +{1366}These apophyses exhibit a remarkable variety in the great subfamily +Theophormida, with open mouth. In the small subfamily Theophaenida, +however, the apophyses appear as six or nine simple lateral wings on the +abdomen. + +The Theophormida are richly represented not only in the present seas, but +also as fossils in Barbados, and numerous remarkable forms have been +already described by Ehrenberg, in his genera _Calocyclas_ and +_Cycladophora_. Many Phormocyrtida belong to the most elegant and admirable +forms of Radiolaria. + +_Synopsis of the Genera of Phormocyrtida._ + + ------------------------------------------------------------------------- + I. Subfamily Theophormida. + Terminal mouth of the abdomen a simple wide opening. + -------------------- + Radial ribs enclosed in the wall of the shell, either the thorax + or the abdomen. + ------------------------------------------------------------------------- + { Abdomen flat, dilated, with + { a wide open mouth, 601. _Theophormis_. + Radial ribs in { + the thorax and { + the abdomen. { Abdomen ovate or cylindrical, + { with constricted + { mouth, 602. _Phormocyrtis_ + + { Peristome with free terminal + Radial ribs in { feet, 603. _Alacorys_. + the abdomen { + only. { Peristome smooth, without + { free feet, 604. _Cycladophora_. + ------------------------------------------------------------------------- + No radial ribs in the shell wall. Peristome with a corona of + terminal feet. + ------------------------------------------------------------------------- + { Abdomen cylindrical or + Terminal { ovate, not dilated, 605. _Calocyclas_. + corona simple. { + { Abdomen dilated, truncate, + { conical or discoidal, 606. _Clathrocyclas_. + + { Both coronas terminal, 607. _Lamprocyclas_. + Corona of feet { + double. { One corona, terminal, the + { other lumbar, 608. _Diplocyclas_. + ------------------------------------------------------------------------- + II. Subfamily Theophaenida. + ------------------------------------------------------------------------- + Terminal mouth of the { Six lateral wings, 609. _Hexalatractus_. + abdomen closed by a { + lattice-plate. { Nine Lateral wings, 610. _Theophaena_. + + + +Subfamily 1. THEOPHORMIDA, Haeckel, 1881, Prodromus, p. 436. + +_Definition._--#Phormocyrtida# with the basal mouth of the shell open (vel +Tricyrtida multiradiata aperta). + + + +Genus 601. _Theophormis_,[218] Haeckel, 1881, Prodromus, p. 436. + +_Definition._--#Theophormida# (vel Tricyrtida multiradiata aperta) with +numerous radial ribs enclosed in the wall of the thorax and of the flat +dilated abdomen; mouth of the latter wide open. + +{1367}The genus _Theophormis_ commences the series of the Theophormida, or +the multiradiate Podocyrtida, as their oldest and simplest form. The +three-jointed shell is flat, campanulate or hat-shaped, and pierced by four +or more radial ribs, four of which are primary or perradial, the others +secondary or interradial. _Theophormis_ may be derived from the similar +_Sethophormis_ by development of a lumbar constriction, and a third joint +or abdomen. + + +1. _Theophormis callipilium_, n. sp. (Pl. 70, figs. 1-3). + +Shell flat, hat-shaped, with two sharp annular strictures. Cephalis large, +flatly cap-shaped, with small, irregular, square meshes (fig. 3). The +collar septum (fig. 2) is composed (as in the following species) of four +crossed, thin, horizontal beams, each of which is inserted at the collar +stricture by a three forked branch. From the centre of the collar stricture +(in the common nodal point of the four beams) there arises a vertical, +axial rod, which is inserted at the flat top of the cephalis by five +branches (one central and four lateral). Length of the three joints = +1 : 3 : 2, breadth = 2 : 6 : 11. Thorax flat, campanulate, with four +primary perradial ribs (prolongations of the four cortinar beams), and +numerous (twenty to thirty) interpolated secondary ribs; four of these are +in interradial (midway between the four primary ribs), and bisect the four +large, semicircular, perradial meshes at the base of the thorax. Network of +the thorax and abdomen subregular, with hexagonal meshes and thin bars. +Abdomen flatly expanded, somewhat curved, like the brim of a hat, half as +broad in the anterior (frontal) part as in the posterior (occipital) part, +which is about as broad as the radius of the thorax. The twenty to thirty +radial ribs of the abdomen are prolongations of the thoracic ribs, and are +somewhat prominent at the margin of the peristome, which appears therefore +elegantly indented. + +_Dimensions._--Length of the three joints, _a_ 0.02 to 0.03, _b_ 0.06 to +0.08, _c_ 0.03 to 0.06; breadth, _a_ 0.05 to 0.08, _b_ 0.2 to 0.3, _c_ 0.4 +to 0.5. + +_Habitat._--Central Pacific, Station 271, surface. + + +2. _Theophormis medusa_, n. sp. + +Shell flatly campanulate, with two distinct, annular strictures. Length of +the three joints = 1 : 2 : 1, breadth = 2 : 5 : 8. Cephalis large, +hemispherical. Thorax flatly conical, with four crossed ribs, opposite in +pairs in two meridional planes, perpendicular one to another, and prolonged +into the flat, nearly discoidal abdomen, which is half as broad as the +thorax. The wall of the abdomen is pierced by eight radial ribs; four +secondary ribs being interpolated between the four primary. Network of the +entire shell very delicate, with regular, hexagonal meshes, and very thin +bars. Peristome circular, not dentate. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.07, _c_ 0.04; +breadth, _a_ 0.06, _b_ 0.16, _c_ 0.24. + +_Habitat._--Central Pacific, Station 266, surface. + + +3. _Theophormis cruciata_, n. sp. + +Shell flat, campanulate, with two distinct annular strictures. Cephalis +flat, cap-shaped, with irregular, square meshes. Thorax flat, conical, with +hexagonal meshes. Abdomen flatly expanded, {1368}of half the breadth, with +larger hexagonal meshes. Thorax and abdomen pierced by four stout radial +ribs, lying opposite in pairs in two diameters, perpendicular one to +another. No secondary or interradial ribs are interpolated between the four +primary. Mouth truncate, circular. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.08, _c_ 0.04; +breadth, _a_ 0.05, _b_ 0.18, _c_ 0.25. + +_Habitat._--Central Pacific, Station 274, surface. + + +4. _Theophormis senaria_, n. sp. + +Shell flat, hat-shaped, similar to _Theophormis callipilium_ (Pl. 70, figs. +1-3), but with a different number and arrangement of the piercing radial +ribs. The cephalis and its collar septum exhibit the same formation as in +_Sethophormis hexalactis_, described above (p. 1245, Pl. 56, fig. 6.) The +caudal and sternal ribs, which are opposed in the sagittal plane, are +simple, whilst the two lateral ribs are forked. In the flat abdomen there +are six secondary or interradial ribs, interpolated between the six primary +or perradial ribs of the thorax. Delicate network with regular, hexagonal +meshes. + +_Dimensions._--Length of the three joints, _a_ 0.035, _b_ 0.075, _c_ 0.025; +breadth, _a_ 0.07, _b_ 0.2, _c_ 0.3. + +_Habitat._--Central Pacific, Station 272, surface. + + + +Genus 602. _Phormocyrtis_,[219] n. gen. + +_Definition._--#Theophormida# (vel Tricyrtida multiradiata aperta) with +numerous radial ribs enclosed in the wall of the thorax, and of the ovate +or cylindrical abdomen; mouth of the latter constricted. + +The genus _Phormocyrtis_ differs from the preceding _Theophormis_ in the +ovate or cylindrical form of the abdomen, the mouth of which is more or +less constricted. The former exhibits, therefore, the same relation to the +latter that _Sethamphora_ bears to _Sethophormis_ among the Dicyrtida. +_Phormocyrtis_ may be derived directly either from _Sethamphora_ by +development of an abdomen, or from _Pterocorys_ or _Theopilium_ by +multiplication of the three radial ribs. + + +1. _Phormocyrtis carinata_, n. sp. + +Shell ovate, with two slight strictures. Length of the three joints = +1 : 2 : 3, breadth = 1 : 3 : 4. Cephalis hemispherical, with a stout +pyramidal horn of twice the length, and few very small pores. Pores in the +campanulate thorax and the inflated abdomen regular, circular, small, and +numerous. Six stout prominent ribs, beginning from the collar stricture, +arise along the thorax and abdomen, and reach the constricted mouth, which +is half as broad as the abdomen. (This species is very similar to +_Pterocorys carinata_, from which it differs in the six complete radial +ribs of the shell-wall.) + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.06, _c_ 0.09; +breadth, _a_ 0.03, _b_ 0.09, _c_ 0.12. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + +{1369}2. _Phormocyrtis fastosa_, Haeckel. + + _Eucyrtidium fastosum_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 291, Taf. ix. fig. 19. + +Shell ovate, with two distinct strictures. Length of the three joints = +1 : 3 : 3, breadth = 1 : 5 : 6. Cephalis ovate, with a stout pyramidal horn +of the same length, and numerous rather large pores. Pores in the +campanulate thorax and the inflated abdomen much smaller, very numerous, +regular, hexagonal. Along these two joints arise nine delicate, divergent +ribs; these extend almost to the wide mouth, which is slightly constricted. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.09, _c_ 0.08; +breadth, _a_ 0.02, _b_ 0.1, _c_ 0.12. + +_Habitat._--Indian Ocean (Zanzibar), depth 2200 fathoms, Pullen. + + +3. _Phormocyrtis costata_, n. sp. (Pl. 69, fig. 6). + +Shell smooth, with sharp collar, but indistinct lumbar stricture. Length of +the three joints = 2 : 5 : 5, breadth = 2 : 6 : 6. Cephalis conical, with a +stout pyramidal horn of twice the length. Thorax and abdomen together +nearly cylindrical, constricted towards both poles, with thirty to forty +longitudinal ribs, which are nearly parallel, vertical in the middle part, +and convergent towards both poles; alternate with the same number of +longitudinal rows of regular, circular pores. Mouth with a broad, hyaline, +only slightly constricted peristome. + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.1, _c_ 0.1; +breadth, _a_ 0.04, _b_ 0.12, _c_ 0.12. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +4. _Phormocyrtis embolum_, Haeckel. + + _Eucyrtidium embolum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 70, Taf. x. fig. 5. + +Shell smooth, with sharp collar, but indistinct lumbar stricture. Length of +the three joints = 3 : 7 : 10, breadth = 3 : 9 : 7. Cephalis subspherical, +with a pyramidal horn of the same length. Thorax campanulate; abdomen +inversely truncate, conical; both with sixteen to twenty longitudinal ribs, +and alternate longitudinal rows of small circular pores, converging towards +the two poles. Mouth truncate, with broad hyaline peristome. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.07, _c_ 0.1; +breadth, _a_ 0.03, _b_ 0.09, _c_ 0.07. + +_Habitat._--Central Pacific, Stations 265 to 268, depth 2700 to 2900 +fathoms; fossil in Barbados. + + +5. _Phormocyrtis quadrata_, n. sp. + +Shell ovate, papillate, with two slight strictures. Length of the three +joints = 2 : 3 : 13, breadth = 4 : 6 : 11. Cephalis hemispherical, small, +with two divergent, pyramidal horns of twice the length. Along the +hemispherical thorax and the ovate inflated abdomen run twenty-four to +thirty curved ribs, converging towards the two poles, and alternate with +the same number of {1370}longitudinal rows of circular, regular pores, +disposed in ten to twelve transverse rows. Each pore with a square, +elevated frame. Mouth constricted, only one-third as broad as the thorax. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.03, _c_ 0.13; +breadth, _a_ 0.04, _b_ 0.06, _c_ 0.11. + +_Habitat._--North Pacific, Station 253, depth 3125 fathoms. + + +6. _Phormocyrtis longicornis_, n. sp. (Pl. 69, fig. 15). + + _Theocorys longicornis_, Haeckel, 1881, Prodromus et Atlas, _loc. cit._ + +Shell slender, ovate, rough, with two slight strictures. Length of the +three joints = 3 : 8 : 12, breadth = 4 : 10 : 11. Cephalis hemispherical, +with a very large, cylindrical horn, about as long as the shell. Thorax +hemispherical, with regular, circular, hexagonally-framed pores. Abdomen +subcylindrical, with twenty to twenty-four nearly parallel undulate ribs, +and alternate longitudinal rows of regular, circular pores. Mouth +constricted, circular, about half as broad as the thorax. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.08, _c_ 0.12; +breadth, _a_ 0.04, _b_ 0.1, _c_ 0.11. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms; also fossil +in Barbados. + + + +Genus 603. _Alacorys_,[220] Haeckel, 1881, Prodromus, p. 436. + +_Definition._--#Theophormida# (vel Tricyrtida multiradiata aperta) with +numerous radial ribs in the abdomen, which are prolonged over the mouth +into free feet. + +The genus _Alacorys_ and the following _Cycladophora_ differ from the +preceding two genera in the formation of the radial ribs, which arise from +the lumbar stricture, and lie in the wall of the abdomen, but are absent on +the thorax. The shell is usually large, more or less pyramidal or conical, +with a wide open terminal mouth. The latter is in _Cycladophora_ simply +truncate, whilst in _Alacorys_ it is surrounded by from four to twelve or +more terminal feet, prolongations of the abdominal ribs. According to the +different number of these (four, five, six, or more) some subgenera may be +distinguished, as _Tetralacorys_, _Pentalacorys_, _Hexalacorys_, &c. + + + +Subgenus 1. _Tetralacorys_, Haeckel, 1881, Prodromus, p. 436. + +_Definition._--Peristome armed with four feet, opposite in two meridian +planes, which are perpendicular to one another. + + +1. _Alacorys lutheri_, n. sp. (Pl. 65, fig. 4). + +Shell papillate, with distinct collar stricture. Length of the three joints += 3 : 6 : 6, breadth = 3 : 8 : 10. Cephalis subspherical, with a pyramidal +horn of the same length. Thorax tuberculate, {1371}nearly hemispherical, +with circular pores of very different sizes. From the margin of its wide +open mouth descend four stout perradial ribs, which are forked at the +distal end, and by communication of their fork-branches form the four +large, pentagonal holes of the abdomen. From the middle of the lower margin +of the holes descend four parallel, vertical, slender feet, about as long +as the shell. This species is dedicated to the memory of the great +Reformer, Martin Luther. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.06, _c_ 0.06; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.1. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +2. _Alacorys tetracantha_, Haeckel. + + _Podocyrtis tetracantha_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 82, Taf. xiii. fig. 2. + + ? _Podocyrtis parvipes_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 82, Taf. xiv. fig. 5. + +Shell rough, with distinct collar stricture. Length of the three joints = +1 : 3 : 5, breadth = 1 : 4 : 6. Cephalis subspherical, with a rudimentary +conical horn. Thorax campanulate, with irregular, roundish pores of +different sizes. Abdomen inflated, with a small number of very large +irregular holes, intermingled with smaller roundish holes. From the margin +of the wide open mouth descend, nearly vertically, four strong vertical +feet, which are about as long as the shell, and slightly curved, with +convex outlines. _Podocyrtis parvipes_ of Ehrenberg seems to be only a +mutilated specimen of this species. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.09; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.13. + +_Habitat._--Fossil in Barbados. + + + +Subgenus 2. _Pentalacorys_, Haeckel, 1881, Prodromus, p. 436. + +_Definition._--Peristome armed with five feet, one of which is odd and +occipital, the other four paired and lateral. + + +3. _Alacorys pentacantha_, Haeckel. + + _Podocyrtis pentacantha_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 82, Taf. xvii. fig. 1. + +Shell rough, with slight collar stricture. Length of the three joints = +1 : 2 : 3, breadth = 1 : 4 : 6. Cephalis subspherical, with a rudimentary +conical horn. Thorax campanulate, with subregular, circular, quincuncial +pores. Abdomen wider, campanulate, with a small number of very large and +irregular, roundish holes. From the peristome descend five stout conical +feet, which are slightly curved and divergent, nearly as long as the shell. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.05, _c_ 0.06; +breadth, _a_ 0.025, _b_ 0.08, _c_ 0.11. + +_Habitat._--Fossil in Barbados. + + +{1372}4. _Alacorys bismarckii_, n. sp. (Pl. 65, fig. 3). + +Shell spiny, with distinct collar stricture. Length of the three joints = +1 : 4 : 5, breadth = 2 : 7 : 10. Cephalis hemispherical, with a very stout, +dimpled, conical horn of the same length. Thorax campanulate, spiny, with +regular, circular pores. Abdomen wider, campanulate, with larger conical +spines, and a small number of irregular, roundish, very large holes. From +the peristome descend, nearly vertically, five very large cylindrical feet, +nearly twice as long as the shell; they are S-shaped, curved, spinulate in +the distal half, and armed at the proximal base with two stout conical +spines, the smaller of which is directed inwards, the larger curved +upwards. Dedicated to Prince Otto von Bismarck, the Reconstructor of the +German Empire. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.08, _c_ 0.1; +breadth, _a_ 0.04, _b_ 0.14, _c_ 0.2. + +_Habitat._--Western Tropical Pacific (north of New Guinea), Station 220, +depth 1100 fathoms. + + + +Subgenus 3. _Hexalacorys_, Haeckel, 1881, Prodromus, p. 436. + +_Definition._--Peristome armed with six feet, three of which are primary or +perradial (Podocyrtis), the three other alternate, secondary or +interradial. + + +5. _Alacorys friderici_, n. sp. (Pl. 65, fig. 1). + +Shell conical, rough, with sharp collar stricture. Cephalis subspherical, +with a large, oblique, prismatic horn, twice the length. Thorax +campanulate, with regular, circular pores (six to eight in its length). +Abdomen wider, campanulate, with a small number of very large pores (three +to four in the course of its length). Peristome with six very large +divergent feet, which are about as long as the shell, cylindrical, +irregularly curved. The specimen figured was observed living, with expanded +pseudopodia. The central capsule exhibited four large pear-shaped lobes, +filling up the shell-cavity; each contained an oil-globule in the thoracic +part. The undivided cephalic part of the capsule enclosed a nucleus, from +which four lobes protruded through the four collar pores into the thorax. +Dedicated to Frederick the Great, the Royal Philosopher of Potsdam. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.06, _c_ 0.08; +breadth, _a_ 0.04, _b_ 0.09, _c_ 0.14. + +_Habitat._--North Atlantic, Canary Islands, Lanzerote (Haeckel), surface. + + +6. _Alacorys guilelmi_, n. sp. (Pl. 65, fig. 2). + +Shell thorny, with distinct collar stricture. Length of the three joints = +1 : 3 : 4, breadth = 2 : 5 : 8. Cephalis hemispherical, with a rudimentary +conical horn. Thorax hemispherical, spiny, with regular, circular pores. +Abdomen wider, campanulate, papillate, with a small number of very large +circular holes. Peristome with six diverging feet, which are about as long +as the shell, at the base conical, thickened, and at the distal end curved +inwards, with a spinulate knob. Dedicated to the German Emperor, Wilhelm. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.08; +breadth, _a_ 0.03, _b_ 0.1, _c_ 0.16. + +_Habitat._--Western Tropical Pacific, Station 224, depth 1850 fathoms. + + +{1373}7. _Alacorys hexacantha_, n. sp. + +Shell thorny, with slight collar stricture. Length of the three joints = +2 : 5 : 7, breadth = 4 : 10 : 14. Cephalis flat, cap-shaped, with a +rudimentary conical horn. Thorax campanulate, with regular, circular pores. +Abdomen wider, campanulate, with a small number of very large polygonal +pores. Peristome with six large divergent feet, which are longer than the +shell, cylindrical, and slightly curved, in the proximal half convex, in +the distal half concave. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.05, _c_ 0.07; +breadth, _a_ 0.04, _b_ 0.1, _c_ 0.14. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +8. _Alacorys hexapleura_, n. sp. + +Shell spiny, with distinct collar stricture. Length of the three joints = +2 : 10 : 8, breadth = 3 : 11 : 10. Cephalis hemispherical, large, hyaline, +and thick-walled, with a very stout, conical horn of the same length. +Thorax pear-shaped, with numerous, regular, circular pores and conical +spines, the size of which increases gradually towards the deep, lumbar +stricture. Abdomen truncate, conical, with irregular, roundish pores, and +six very strong, straight, divergent ribs, prolonged into six short, +conical feet. + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.2, _c_ 0.16; +breadth, _a_ 0.06, _b_ 0.22, _c_ 0.2. + +_Habitat._--Fossil in Barbados. + + + +Subgenus 4. _Octalacorys_, Haeckel. + +_Definition._--Peristome armed with eight feet, four of which are primary +or perradial (corresponding to those of _Tetralacorys_), the other four +alternate, secondary, or interradial. + + +9. _Alacorys aculeata_, Haeckel. + + _Podocyrtis aculeata_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 80, Taf. xiii. fig. 3. + + _Podocyrtis aculeata_, Buetschli, 1882, Zeitschr. f. wiss. Zool., vol. + xxxvi. p. 540, Taf. xxxiii. fig. 34. + +Shell spiny, with deep collar stricture. Length of the three joints = +2 : 5 : 8, breadth = 2 : 7 : 10. Cephalis subspherical, with a slender, +conical horn of twice the length. Thorax campanulate, thorny, with regular, +circular pores. Abdomen wider, campanulate, with a small number of very +large, regular, hexagonal meshes, and stout spines in the nodal points. +Peristome with eight strong conical feet, which are nearly parallel, little +curved (convex at the outside), and sometimes all of the same size (equal +to the length of the shell); at other times different, four larger +alternating with four smaller feet. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.05, _c_ 0.08; +breadth, _a_ 0.025, _b_ 0.07, _c_ 0.1. + +_Habitat._--Fossil in Barbados. + + +{1374}10. _Alacorys octacantha_, n. sp. + +Shell spiny, with deep collar stricture. Length of the three joints = +2 : 8 : 6, breadth = 3 : 7 : 7. Cephalis ovate, with a short, conical horn. +Thorax pear-shaped, spiny, with regular, circular pores, similar to +_Cycladophora erinaceus_, Ehrenberg (1875, Abhandl. d. k. Akad. d. Wiss. +Berlin, p. 68, Taf. xviii. fig. 2). Abdomen truncate, conical, with +irregular, roundish pores, and eight stout, straight, thorny, divergent +ribs of equal size, which are prolonged into eight free, conical, spiny +feet of the same length. + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.16. _c_ 0.12; +breadth, _a_ 0.06, _b_ 0.14, _c_ 0.14. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + + +Subgenus 5. _Ennealacorys_, Haeckel. + +_Definition._--Peristome armed with nine feet, three of which are primary +or perradial, the other six secondary or interradial. + + +11. _Alacorys enneacantha_, n. sp. + +Shell papillate, with slight collar stricture. Length of the three joints = +2 : 4 : 8, breadth = 3 : 6 : 9. Cephalis hemispherical, with a stout, +conical horn of twice the length. Thorax campanulate, with subregular, +circular pores, and small, conical papillae. Thorax wider, campanulate, +with circular pores, and conical papillae of three times the size. +Peristome with nine widely divergent, little curved, conical feet, about as +long as the shell. Similar to _Podocyrtis ventricosa_, Ehrenberg (1875, +_loc. cit._, Taf. xvi. fig. 3), different mainly in the feet. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.08; +breadth, _a_ 0.03, _b_ 0.06, _c_ 0.09. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +12. _Alacorys gigas_, n. sp. + +Shell thorny, with distinct collar stricture. Length of the three joints = +1 : 4 : 2, breadth = 1 : 5 : 4. Cephalis ovate, with a short, conical horn +of about half the length. Thorax campanulate, thorny, with small, regular, +circular pores, very similar to _Cycladophora gigas_, Ehrenberg (_loc. +cit._, 1875, p. 68, Taf. xviii. fig. 1). Abdomen truncate, conical, smooth, +with irregular, roundish pores, and nine stout and straight, little +divergent ribs, which are prolonged into nine cylindrical, pointed feet of +the same length. + +_Dimensions._--Length of the three joints, _a_ 0.05, _b_ 0.2, _c_ 0.1; +breadth, _a_ 0.05, _b_ 0.25, _c_ 0.2. + +_Habitat._--Fossil in Barbados. + + + +Subgenus 6. _Polyalacorys_, Haeckel. + +_Definition._--Peristome with numerous (ten to twenty or more) prominent +feet, three or four of which are primary and perradial, the others +secondary and interradial. + + +{1375}13. _Alacorys dodecantha_, n. sp. + + ? _Podocyrtis schomburgkii_, var., Bury, 1862, Polycystins of Barbados, + Taf. xii. fig. 3. + +Shell smooth, with slight collar stricture. Length of the three joints = +1 : 3 : 4, breadth = 1 : 4 : 7. Cephalis ovate, with a conical horn of the +same length. Thorax campanulate, with regular, circular pores. From its +margin arise twelve stout, little curved, radial beams, which are widely +divergent, and connected in the middle part by a transverse circular ring, +so that the abdomen exhibits twelve large triangular holes, and at the +peristome, alternating with these, twelve free conical feet of the same +length. + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.09, _c_ 0.11; +breadth, _a_ 0.03, _b_ 0.12, _c_ 0.22. + +_Habitat._--Central Pacific, Station 263, depth 2650 fathoms; also fossil +in Barbados. + + +14. _Alacorys carcinus_, n. sp. (Pl. 74, fig. 9). + + _Calocyclas carcinus_, Haeckel, 1879, Atlas, _loc. cit._ + + _Podocyrtis schomburgkii_, var., Bury, 1862, Polycystins of Barbados, pl. + i. fig. 2; pl. xii. fig. 4. + +Shell rough, with distinct collar stricture. Length of the three joints = +1 : 4 : 4, breadth = 2 : 6 : 6. Cephalis hemispherical, with a large, +cylindrical, bent spine of three times the length. Thorax inflated, +campanulate, with large, regular, circular pores. Abdomen truncate, +conical, with three to four transverse rows of regular, square pores, +produced by eighteen divergent, straight ribs, which are connected by three +to four horizontal rings. Distal end of the ribs prolonged into eighteen +slender, conical feet, which are about as long as the thorax and slightly +curved inwards. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.08, _c_ 0.08; +breadth, _a_ 0.05, _b_ 0.12, _c_ 0.12. + +_Habitat._--Central Pacific, Stations 265 to 268, depth 2700 to 2900 +fathoms; also fossil in Barbados. + + +15. _Alacorys polyacantha_, n. sp. + +Shell spiny, with deep collar stricture. Length of the three joints = +3 : 9 : 10, breadth = 4 : 12 : 16. Cephalis hemispherical, with a stout +conical horn of the same length. Thorax campanulate, with regular, circular +pores and conical spines, increasing in size towards the deep lumbar +stricture. Abdomen truncate, conical, with twenty to thirty divergent, +straight ribs, which are connected by four to six transverse rings, and +prolonged into free conical feet of half the length. Therefore four to six +transverse rings of regular, square pores occur. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.09, _c_ 0.1; +breadth, _a_ 0.04, _b_ 0.12, _c_ 0.16. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +16. _Alacorys ornata_, Haeckel. + + _Cryptoprora ornata_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 68, Taf. v. fig. 8. + +Shell ovate, smooth, without external strictures, but with two internal +annular septa. Length of the three joints = 3 : 5 : 4, breadth = 3 : 6 : 5. +Cephalis subspherical, partly enclosed by the uppermost part of the thorax, +without horn, or with a small rudimentary horn. Pores subregular, +{1376}circular, half as broad in the cephalis as in the two other joints. +Thorax campanulate. Abdomen truncate, with eighteen to twenty-four +parallel, vertical, longitudinal ribs, which are prolonged into slender, +free, conical feet of the same length. (This remarkable species may be +derived from _Carpocanium_ by apposition of a third joint.) + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.05, _c_ 0.04; +breadth, _a_ 0.03, _b_ 0.06, _c_ 0.05. + +_Habitat._--Fossil in Barbados. + + + +Genus 604. _Cycladophora_,[221] Ehrenberg, 1847, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 54. + +_Definition._--#Theophormida# (vel Tricyrtida multiradiata aperta) with +four to six or more radial ribs in the abdomen, the terminal mouth of which +is truncate, without feet. + +The genus _Cycladophora_ differs from the preceding _Alacorys_, its +probable ancestral genus, in the absence of free terminal feet, the radial +ribs of the abdomen being connected by transverse beams throughout their +whole length. The number of the regularly disposed ribs (four to six or +more) may also here be used for the distinction of different subgenera. + + + +Subgenus 1. _Lampterium_, Haeckel, 1881, Prodromus, p. 434. + +_Definition._--Abdomen with four radial ribs, opposite in pairs in two +meridian planes, perpendicular one to another. + + +1. _Cycladophora goetheana_, n. sp. (Pl. 65, fig. 5). + +Shell shaped like a lantern, with two sharp strictures. Length of the three +joints = 1 : 2 : 12, breadth = 1 : 4 : 7. Cephalis hemispherical, with a +slender pyramidal horn of three times the length. Thorax twice as large, +thorny, hemispherical, with regular, circular pores. Abdomen very long, +nearly four-sided prismatic, with four superior smaller, and four inferior +larger holes; the former separated by four short, divergent, perradial, the +latter by four long, parallel, vertical, interradial bars. Mouth square, +four-lobed. Dedicated to Wolfgang Goethe. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.24; +breadth, _a_ 0.03, _b_ 0.07, _c_ 0.1 to 0.14. + +_Habitat._--Central Pacific, Stations 265 to 269, depth 2550 to 2900 +fathoms. + + +2. _Cycladophora tetrapleura_, n. sp. + +Shell very similar to the preceding species, but differing in the following +characters: Cephalis conical, with a horn of the same length. Thorax +campanulate. Four ribs of the abdomen not {1377}parallel and vertical, but +more or less divergent. Length of the three joints = 1 : 2 : 8, breadth = +1 : 2 : 4. Whole shell slender, pyramidal. Mouth square, four-lobed. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.06, _c_ 0.24; +breadth, _a_ 0.03, _b_ 0.06, _c_ 0.12. + +_Habitat._--North Pacific, Station 241, depth 2300 fathoms. + + +3. _Cycladophora lanterna_, n. sp. + +Shell very similar to the two preceding species, but differing in the +following characters. Cephalis subspherical, with a thick, pyramidal horn +of the same breadth, and three times the length. Thorax hemispherical, with +circular, hexagonally-framed pores. Abdomen ovate, with four convex ribs, +and twelve large holes, four superior smaller pentagonal, four intermediate +very large, ovate, and four inferior, small, triangular holes. Mouth little +constricted, nearly circular. + +_Dimensions._--Length of the three joints, _a_ 0.025, _b_ 0.05, _c_ 0.22; +breadth, _a_ 0.025, _b_ 0.08, _c_ 0.11. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + + +Subgenus 2. _Lamptidium_, Haeckel. + +_Definition._--Abdomen with six radial ribs (three primary or perradial, +and three alternate, secondary or interradial). + + +4. _Cycladophora hexapleura_, n. sp. + + _Lanterna chinensis_, Bury, 1862, Polycystins of Barbados, pl. xiii. fig. + 7. + +Shell shaped like a lantern, with six sides and two sharp strictures. +Length of the three joints = 1 : 2 : 8, breadth = 1 : 2 : 4. Cephalis +hemispherical, with a conical spine of the same length. Thorax twice as +large, hemispherical, with regular, circular pores. Abdomen nearly +six-sided prismatic, with six descending, little curved ribs, and eighteen +large holes between them; six superior holes interradial, ovate, six +intermediate holes very large, perradial, ovate, six inferior holes +triangular, interradial. Mouth six-lobed. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.16; +breadth, _a_ 0.03, _b_ 0.06, _c_ 0.1. + +_Habitat._--Fossil in Barbados. + + +5. _Cycladophora pyramidalis_, n. sp. + + _Podocyrtis_ sp., Bury, 1862, Polycystins of Barbados, pl. xii. fig. 2. + +Shell slender, pyramidal, with six sides and two slight strictures. Length +of the three joints = 1 : 4 : 12, breadth = 1 : 4 : 8. Cephalis +subspherical, with a conical horn of twice the length. Thorax conical, with +regular, circular pores. Abdomen truncate, pyramidal, with six strong, +divergent, straight ribs, which are connected by five to six transverse, +hexagonal rings; therefore {1378}six longitudinal rows of large, roundish, +quadrangular meshes (four to five meshes in each row). Mouth hexagonal. + +_Dimensions._--Length of the three joints, _a_ 0.025, _b_ 0.1, _c_ 0.3; +breadth, _a_ 0.03, _b_ 0.1, _c_ 0.2. + +_Habitat._--Fossil in Barbados. + + +6. _Cycladophora spinosa_, n. sp. + +Shell spiny, with two deep strictures. Length of the three joints = +1 : 4 : 3, breadth = 1 : 5 : 4. Cephalis subspherical, with a stout conical +horn of the same length. Thorax ovate, with regular, circular pores, and +numerous conical spines. Abdomen truncate, conical, with irregular, +roundish pores, and six strong, divergent ribs. Mouth circular. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.12, _c_ 0.09; +breadth, _a_ 0.03, _b_ 0.15, _c_ 0.12. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms; fossil in +Barbados. + + + +Subgenus 3. _Lamptonium_, Haeckel. + +_Definition._--Abdomen with nine radial ribs (three primary or perradial, +and six secondary or interradial). + + +7. _Cycladophora enneapleura_, n. sp. + +Shell spiny, with two sharp strictures. Length of the three joints = +1 : 5 : 3, breadth = 2 : 7 : 4. Cephalis hemispherical, with a conical horn +of twice the length. Thorax campanulate, with regular, circular pores, and +conical thorax. Abdomen cylindrical, with nine straight, parallel ribs, and +irregular, roundish pores. Mouth circular. (_Similar to Cycladophora +gigas_, Ehrenberg, 1875, _loc. cit._, Taf. xviii. fig. 1, but differing in +the possession of nine abdominal ribs.) + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.15, _c_ 0.1; +breadth, _a_ 0.06, _b_ 0.2, _c_ 0.12. + +_Habitat._--South Pacific, Station 295, depth 1500 fathoms. + + +8. _Cycladophora nonagona_, n. sp. + +Shell spiny, with two distinct strictures. Length of the three joints = +3 : 10 : 7, breadth = 2 : 9 : 8. Cephalis pear-shaped, with a stout +pyramidal horn of the same length. Thorax pear-shaped, with regular, +circular pores, and conical horns, increasing in size towards the base. +Abdomen truncate, pyramidal, with nine straight, spinulate ribs, and nine +even faces between them, with irregular, roundish pores. Mouth nonagonal. + +_Dimensions._--Length of the three joints, _a_ 0.06, _b_ 0.2, _c_ 0.14; +breadth, _a_ 0.05, _b_ 0.18, _c_ 0.16. + +_Habitat._--Fossil in Barbados. + + + +{1379}Subgenus 4. _Cyclampterium_, Haeckel. + +_Definition._--Abdomen truncate, conical or campanulate, with numerous (ten +to twenty or more) divergent ribs. Mouth wide open, truncate. + + +9. _Cycladophora pantheon_, n. sp. (Pl. 68, fig. 3). + +Shell dome-shaped, with slight collar and deep lumbar stricture. Length of +the three joints = 1 : 6 : 5, breadth = 1 : 7 : 8. Cephalis small, with a +conical horn of the same length. Thorax cupola-shaped, with large, regular, +circular pores, and numerous pyramidal tubercles. Abdomen with twelve +(sometimes eleven or thirteen) slender, divergent ribs, which are connected +at equal distances by four to six horizontal rings, and so produce twelve +longitudinal rows of large, regular, square meshes. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.12, _c_ 0.1; +breadth, _a_ 0.03, _b_ 0.14, _c_ 0.15. + +_Habitat._--Central Pacific, Stations 263 to 274, depth 2350 to 2925 +fathoms. + + +10. _Cycladophora dodecapleura_, n. sp. + +Shell cupola-shaped, with two deep strictures. Length of the three joints = +2 : 5 : 6, breadth = 2 : 7 : 10. Cephalis hemispherical, with a conical +horn of twice the length. Thorax subspherical, truncate at both poles, +thorny, with regular, circular pores. Abdomen in the upper half with a +coronal of twelve large ovate holes, separated by twelve divergent, slender +ribs, in the lower half with curved, convergent prolongations of the twelve +ribs, and numerous small, irregular, roundish pores. + +_Dimensions._--Length of the three joints, _a_ 0.015, _b_ 0.05, _c_ 0.06; +breadth, _a_ 0.02, _b_ 0.07, _c_ 0.1. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +11. _Cycladophora campanula_, n. sp. + +Shell campanulate, with two slight strictures. Length of the three joints = +2 : 4 : 5, breadth = 2 : 6 : 10. Cephalis ovate, with a conical horn of the +same length. Thorax campanulate, rough, with regular, circular pores. +Abdomen dilated, with fifteen to twenty slender, divergent, little curved +ribs, which are connected by two or three horizontal rings, and from two or +three transverse rows of large, roundish, square pores. + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.08, _c_ 0.1; +breadth, _a_ 0.04, _b_ 0.12, _c_ 0.2. + +_Habitat._--North Atlantic, Bermuda, surface; also fossil in Barbados. + + +12. _Cycladophora spatiosa_, Ehrenberg. + + _Cycladophora spatiosa_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 68, Taf. xviii. figs. 5, 6. + +Shell campanulate, with two slight strictures. Length of the three joints = +2 : 6 : 9, breadth = 3 : 8 : 14. Cephalis subspherical, with a conical horn +of the same length. Thorax campanulate, {1380}smooth, with regular, +circular pores. Abdomen truncate, conical, with sixteen to twenty-four +divergent ribs, which are straight or slightly curved, and connected by +from four to six transverse, circular rings. The large regular meshes, so +produced, form sixteen to twenty-four longitudinal series, and are rounded +in the upper, square in the lower transverse rows. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.09; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.14. + +_Habitat._--Fossil in Barbados. + + +13. _Cycladophora favosa_, n. sp. (Pl. 62, figs. 5, 6). + +Shell dome-shaped, without collar stricture, but with a deep lumbar +stricture. Cephalis flat, cap-shaped, without horn, or with a rudimentary +conical horn, with small circular pores. Length of the three joints = +1 : 4 : 3, breadth = 2 : 5 : 4. Thorax subspherical, rough, with regular, +circular, hexagonally-framed pores. Abdomen truncate, conical, with +eighteen to twenty-four prominent ribs; between every two ribs only two or +three ovate pores occur. Mouth circular, with eighteen to twenty-four +teeth. The shape of the abdomen is rather variable (figs. 5, 6). + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.08, _c_ 0.06; +breadth, _a_ 0.04, _b_ 0.09, _c_ 0.07. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + + +Subgenus 5. _Cyclamptidium_, Haeckel. + +_Definition._--Abdomen nearly cylindrical or prismatic, with numerous (ten +to twenty or more) straight, vertical, parallel ribs. Mouth wide open, +truncate. + + +14. _Cycladophora fenestrata_, n. sp. (Pl. 68, fig. 2). + +Shell rough, with two slight strictures. Length of the three joints = +1 : 5 : 5, breadth = 1 : 6 : 5. Cephalis conical, with a conical, dimpled +horn of twice the length. Thorax nearly spherical, with regular, circular +pores, and small conical spines. Abdomen cylindrical, with eighteen stout, +parallel, vertical ribs, which are connected by six to eight horizontal, +circular rings; therefore regular transverse and longitudinal rows of +square or circular pores occur. Mouth truncate, circular. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.1, _c_ 0.1; +breadth, _a_ 0.03, _b_ 0.12, _c_ 0.1. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +15. _Cycladophora stiligera_, Ehrenberg. + + _Cycladophora stiligera_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 68, Taf. xviii. fig. 3. + +Shell smooth, with two distinct strictures. Length of the three joints = +2 : 7 : 8, breadth = 2 : 9 : 7. Cephalis subspherical, with a conical horn +of twice the length. Thorax subspherical, smooth, with regular, circular +pores. Abdomen cylindrical, with twelve parallel, vertical ribs, which +{1381}are connected by three to four broad, horizontal rings; therefore +subregular, transverse, and longitudinal rows of roundish pores are +present. Mouth truncate, circular. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.07, _c_ 0.08; +breadth, _a_ 0.02, _b_ 0.09, _c_ 0.07. + +_Habitat._--Fossil in Barbados. + + + +Genus 605. _Calocyclas_,[222] Ehrenberg, 1847, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 54. + +_Definition._--#Theophormida# (vel Tricyrtida multiradiata aperta) with a +simple corona of terminal feet around the truncate mouth. Abdomen not +dilated, cylindrical or ovate. No ribs in the shell-wall. + +The genus _Calocyclas_, and the three following closely allied genera, +differ from the four preceding genera of Theophormida in the absence of +radial or longitudinal ribs in the wall of the thorax and abdomen. These +are completely reduced, and their terminal prolongations only remain, +forming a simple or double corona around the mouth of the abdomen. They +correspond therefore to _Carpocanium_ and _Anthocyrtis_ among the +Dicyrtida. In _Calocyclas_ the corona is simple. The mouth is not dilated, +but often constricted, and the abdomen is cylindrical or ovate, not +conical. The teeth of the corona are usually vertical or convergent. + + + +Subgenus 1. _Calocycletta_, Haeckel. + +_Definition._--Thorax and abdomen smooth, without spines or thorns. + + +1. _Calocyclas veneris_, n. sp. (Pl. 74, fig. 5). + +Shell smooth, with two distinct strictures. Length of the three joints = +1 : 2 : 2, breadth = 1 : 4 : 3. Cephalis ovate, with a large, triangular, +prismatic horn of three times the length. Thorax hemispherical; abdomen +cylindrical; both with regular, circular pores of equal size. Mouth +truncate, with a corona of nine to twelve vertical, lamellar feet, which +are as long as the abdomen, rectangular, twice as broad as their distance +apart, and truncate at the end. + +_Dimensions._--Length of the three joints, _a_ 0.03 to 0.04, _b_ 0.06 to +0.08, _c_ 0.04 to 0.06; breadth, _a_ 0.03 to 0.04, _b_ 0.09 to 0.11, _c_ +0.08 to 0.1. + +_Habitat._--Cosmopolitan; Atlantic, Indian, Pacific, many stations; +surface, and in various depths. + + +2. _Calocyclas virginis_, n. sp. (Pl. 74, fig. 4). + +Shell smooth, with distinct collar, but indistinct lumbar stricture. Length +of the three joints = 1 : 2 : 1, breadth = 1 : 4 : 3. Cephalis ovate, with +a slender, conical horn, little shorter than the {1382}shell. Thorax +subspherical. Abdomen nearly cylindrical, little contracted towards the +peristome. Pores regular, circular, twice as broad in the thorax as in the +abdomen, where they are separated by slight longitudinal ribs. Corona of +the peristome composed of sixteen to twenty-four vertical, lamellar feet, +which are longer than the abdomen, rectangular, and truncate at the end. + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.08, _c_ 0.05; +breadth, _a_ 0.03, _b_ 0.11, _c_ 0.09. + +_Habitat._--Central Pacific, Station 225, depth 4475 fathoms. + + +3. _Calocyclas minervae_, n. sp. + +Shell smooth, with two deep strictures, similar to _Cycladophora +stiligera_. Length of the three joints = 1 : 4 : 3, breadth = 1 : 4 : 3. +Cephalis subspherical, with a large, conical horn of three times the +length. Thorax subspherical, with small, regular, circular pores. Abdomen +cylindrical, with truncate mouth and few irregular pores of different +sizes, commonly arranged in three or four subregular, transverse rows, with +large intervening distances. Peristome with a corona of twelve to twenty +vertical, lamellar feet, which are about as long as the abdomen, and +truncate at the end (in Ehrenberg's figure these are broken off). + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.08, _c_ 0.06; +breadth, _a_ 0.02, _b_ 0.09, _c_ 0.07. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +4. _Calocyclas amicae_, n. sp. (Pl. 74, fig. 2). + +Shell smooth, with two slight strictures. Length of the three joints = +2 : 4 : 5, breadth = 2 : 5 : 5. Cephalis subspherical, with a pyramidal +horn of the same length. Thorax campanulate-conical; abdomen nearly +cylindrical; both with small, subregular, circular pores. Peristome with a +corona of twelve to fifteen small, triangular feet, only as large as the +thickness of the shell-wall, and separated by distances of twice the size. + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.08, _c_ 0.1; +breadth, _a_ 0.04, _b_ 0.1, _c_ 0.1. + +_Habitat._--North Pacific, Station 253, depth 3125 fathoms. + + +5. _Calocyclas sacerdotis_, n. sp. + +Shell smooth, with two deep strictures. Length of the three joints = +1 : 3 : 4, breadth = 1 : 3 : 3. Cephalis ovate, with a pyramidal horn of +three times the length. Thorax campanulate, conical; abdomen twice the +length, cylindrical; both with small, regular, circular pores. Peristome +somewhat constricted, with a corona of nine to twelve conical feet, which +are as long as the cephalis, and with the ends curved inwards, protecting +the mouth. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.08, _c_ 0.12; +breadth, _a_ 0.03, _b_ 0.09, _c_ 0.09. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + +6. _Calocyclas vestalis_, n. sp. (Pl. 74, fig. 3). + +Shell smooth, with two deep strictures. Length of the three joints = +1 : 2 : 3, breadth = 1 : 3 : 3. Cephalis subspherical, with a pyramidal +horn of twice the length. Thorax campanulate; abdomen {1383}nearly +cylindrical; both with regular, hexagonal pores, three times as broad as +the bars. Peristome constricted, half as broad as the abdomen, with a +corona of nine conical, vertical feet as long as the cephalis. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.07, _c_ 0.1; +breadth, _a_ 0.035, _b_ 0.1, _c_ 0.1. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +Subgenus 2. _Calocyclissa_, Haeckel. + +_Definition._--Thorax spiny or thorny; abdomen smooth. + + +7. _Calocyclas turris_, Ehrenberg. + + _Calocyclas turris_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 66, Taf. xviii. fig. 7. + +Shell with two sharp strictures. Length of the three joints = 1 : 4 : 4, +breadth = 1 : 5 : 4. Cephalis hemispherical, with a stout conical horn of +the same length. Thorax subspherical, thorny with small, regular, circular, +quincuncial pores. Abdomen cylindrical, smooth, nearly hyaline, with very +scarce, irregular, widely scattered pores. Peristome with a corona of +fifteen to twenty broad, lamellar, vertical, truncate feet, about as long +as the abdomen. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.08, _c_ 0.08; +breadth, _a_ 0.03, _b_ 0.1, _c_ 0.08. + +_Habitat._--Fossil in Barbados. + + +8. _Calocyclas hyalogaster_, n. sp. + +Shell with two sharp strictures. Length of the three joints = 1 : 4 : 6, +breadth = 1 : 4 : 3. Cephalis subspherical, with a conical horn of twice +the length. Thorax subspherical, thorny, with regular, circular pores. +Abdomen cylindrical, smooth, quite hyaline, without any pores. Peristome +with a corona of twelve broad, lamellar, vertical, truncate feet, half as +long as the abdomen. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.08, _c_ 0.12; +breadth, _a_ 0.02, _b_ 0.08, _c_ 0.06. + +_Habitat._--South Pacific, Station 300, depth 1375 fathoms. + + +9. _Calocyclas erinaceus_, Haeckel. + +_Cycladophora erinaceus_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. +Berlin, p. 68, Taf. xviii. fig. 2. + +Shell with two sharp strictures. Length of the three joints = 2 : 9 : 5, +breadth = 3 : 9 : 5. Cephalis subspherical, rough, with a short and broad +conical horn of half the length. Thorax ovate, densely covered with conical +spines as long as the horn, and with regular, circular, quincuncial pores. +Abdomen cylindrical, smooth, with irregular roundish pores of different +sizes. Peristome with twelve to fifteen vertical, broad, lamellar, truncate +feet half as long as the abdomen (in Ehrenberg's figure these are broken +off). + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.18, _c_ 0.1; +breadth, _a_ 0.06, _b_ 0.18, _c_ 0.1. + +_Habitat._--Fossil in Barbados. + + +{1384}10. _Calocyclas gigas_, Haeckel. + + _Cycladophora gigas_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 68, Taf. xviii. fig. 1. + +Shell with two sharp strictures. Length of the three joints = 2 : 5 : 3, +breadth = 2 : 6 : 4. Cephalis subspherical, rough, with a short and broad +conical horn of half the length. Thorax subspherical, campanulate, thorny, +with subregular, circular pores (smaller and more numerous than in the +preceding). Abdomen cylindrical, smooth, with a small number of sparsely +disposed, roundish, irregularly scattered pores. Peristome with twenty to +thirty short, lamellar, truncate, vertical feet about half as long as the +cephalis. + +_Dimensions._--Length of the three joints, _a_ 0.06, _b_ 0.15, _c_ 0.09; +breadth, _a_ 0.06, _b_ 0.18, _c_ 0.12. + +_Habitat._--Fossil in Barbados. + + + +Subgenus 3. _Calocycloma_, Haeckel. + +_Definition._--Thorax smooth; abdomen spiny or thorny. + + +11. _Calocyclas casta_, n. sp. (Pl. 73, fig. 10). + +Shell ovate, with two sharp strictures. Length of the three joints = +1 : 2 : 8, breadth = 2 : 4 : 8. Cephalis hemispherical, with a strong +pyramidal horn of twice the length. Thorax campanulate, smooth, with small, +regular, circular pores. Abdomen inflated, subspherical, covered with large +conical spines, and large intervening circular pores (four times as broad +as the thoracic pores). Mouth constricted, only one-third as broad as the +abdomen, with a peristome of nine to twelve conical vertical feet as long +as the abdominal spines. (In the specimen figured they were broken off.) + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.04, _c_ 0.15; +breadth, _a_ 0.04, _b_ 0.08, _c_ 0.15. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +12. _Calocyclas pudica_, n. sp. + +Shell ovate, with two distinct strictures. Length of the three joints = +1 : 3 : 8, breadth = 1 : 4 : 6. Cephalis subspherical, with a conical horn +of three times the length. Thorax and abdomen nearly of the same shape as +in the preceding species, but more slender and the regular, circular pores +of the abdomen only twice as broad as the thoracic pores. Conical spines of +the abdomen only half as large, but more numerous. Peristome constricted, +half as broad as the abdomen, with sixteen to twenty short, conical, +vertical feet as long as the cephalis. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.16; +breadth, _a_ 0.025, _b_ 0.08, _c_ 0.12. + +_Habitat._--Central Pacific Station 266, depth 2750 fathoms. + + + +Subgenus 4. _Calocyclura_, Haeckel. + +_Definition._--Thorax and abdomen spiny or thorny. + + +{1385}13. _Calocyclas parthenia_, n. sp. (Pl. 74, fig. 1). + +Shell nearly ovate, with thorny surface, and two slight strictures. Length +of the three joints = 1 : 2 : 4, breadth = 2 : 4 : 5. Cephalis +hemispherical, armed with numerous short, conical thorns, and with a +pyramidal, very large, vertical horn as long as the thorax, and on the +basal half as broad as the cephalis. Thorax hemispherical, separated by a +slight stricture from the broader, barrel-shaped abdomen, which is a little +constricted at the mouth. Teeth of the coronal about twenty, triangular, +short, little divergent. Pores circular, somewhat irregular in size, three +to four times as broad as the bars, in all three joints nearly of the same +shape. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.06, _c_ 0.11; +breadth, _a_ 0.05, _b_ 0.1, _c_ 0.12. + +_Habitat._--Indian Ocean, Cocos Islands, surface (Rabbe). + + +14. _Calocyclas aspasia_, n. sp. + +Shell ovate, conical, with two deep strictures. Length of the three joints += 1 : 3 : 4, breadth = 1 : 4 : 5. Cephalis subspherical, with a conical +horn of twice the length. Thorax and abdomen nearly of the same shape as in +the preceding species, but covered with longer conical spines, less +numerous, and twice as long as the diameter of the subregular, circular +pores. Mouth more constricted, and armed with a coronal of twelve to +sixteen broad, lamellar feet, as long as the cephalis, and similar to those +of _Calocyclas puella_ (Pl. 74, fig. 5). + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.08; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.1. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +15. _Calocyclas monumentum_, n. sp. (Pl. 73, fig. 9). + +Shell nearly conical, with two very deep strictures, everywhere covered +with long, bristle-shaped, divergent spines, about as long as the thorax. +Length of the three joints = 1 : 2 : 2, breadth = 1 : 4 : 6. Cephalis +nearly spherical, with a very large, three-sided pyramidal horn of twice +the length. Thorax and abdomen of similar form, campanulate, with a lower +cylindrical, and an upper truncate, conical part. Pores irregular, +roundish, in the smaller thorax of slightly different sizes, in the larger +abdomen three to four transverse rows of larger pores (six to eight in each +row) are separated by numerous much smaller pores. Peristome wide open, +with a coronal of twelve large, triangular, vertical feet, nearly as long +as the abdomen; in the base of each foot a large, roundish, triangular +pore. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.06, _c_ 0.06; +breadth, _a_ 0.04, _b_ 0.12, _c_ 0.18. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +Genus 606. _Clathrocyclas_,[223] Haeckel, 1881, Prodromus, p. 434. + +_Definition._--#Theophormida# (vel Tricyrtida multiradiata aperta) with a +simple corona of terminal feet around the dilated mouth. Abdomen dilated, +truncate-conical, or discoidal. No ribs in the shell-wall. + +{1386}The genus _Clathrocyclas_ differs from the preceding closely allied +_Calocyclas_ in the dilated mouth and the flatter form of the abdomen, +which is usually truncate, conical, or nearly discoidal. The conical thorax +is often separated from the flat abdomen by an elegant ribbon of small +quadrangular pores. The feet or teeth of the terminal corona are divergent, +or even horizontally expanded, whilst in _Calocyclas_ they are usually +vertical or somewhat convergent. + + + +Subgenus 1. _Clathrocyclia_, Haeckel. + +_Definition._--Shell highly conical, often ovate or slenderly campanulate. +Cephalis commonly with a single horn. + + +1. _Clathrocyclas principessa_, n. sp. (Pl. 74, fig. 7). + +Shell ovate, with two distinct strictures. Length of the three joints = +1 : 2 : 1, breadth = 1 : 2 : 2. Cephalis hemispherical, large, with a +pyramidal, occipital horn of the same length. Thorax subspherical, with +irregular, circular pores, about as broad as the bars. Abdomen short, +widely open with a single transverse row of circular pores, and a coronal +of twelve triangular, divergent feet, as long as the abdomen. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.06, _c_ 0.03; +breadth, _a_ 0.04, _b_ 0.08, _c_ 0.09. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +2. _Clathrocyclas basilea_, (Pl. 74, fig. 6). + +Shell campanulate, with two deep strictures. Length of the three joints = +2 : 5 : 3, breadth = 3 : 7 : 9. Cephalis hemispherical, with an ovate, +oblique horn of the same length. Thorax hemispherical, with subregular, +circular pores of the same breadth as the bars. Abdomen short, with two +transverse rows of the same pores, and with a coronal of sixteen to twenty +ovate, divergent feet, as long as the horn. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.05, _c_ 0.03; +breadth, _a_ 0.035, _b_ 0.07, _c_ 0.09. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms. + + +3. _Clathrocyclas fimbriata_, Haeckel. + + ? _Halicalyptra fimbriata_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 72, Taf. ii. fig. 11. + +Shell campanulate, with two deep strictures. Length of the three joints = +1 : 3 : 1, breadth = 1 : 3 : 5. Cephalis hemispherical, with a conical horn +of twice the length. Thorax hemispherical, in the upper half hyaline, +without pores, in the lower half with four to six transverse rows of +subregular, circular pores. Abdomen short, suddenly dilated, with one or +two transverse rows of larger {1387}ovate pores (six to eight in one row), +and with a coronal of twelve to fifteen divergent, slender, curved feet, as +long as the cephalis. (In the figure of Ehrenberg, seen half from below, +the cephalis is not represented.) + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.02; +breadth, _a_ 0.02, _b_ 0.06, _c_ 0.1. + +_Habitat._--Fossil in Barbados. + + +4. _Clathrocyclas collaris_, n. sp. (Pl. 74, fig. 8). + +Shell subconical, with two indistinct strictures. Length of the three +joints = 1 : 1 : 2, breadth = 1 : 2 : 3. Cephalis hemispherical, with a +triangular prismatic horn three times the length. Thorax truncate, conical, +with a single transverse row of circular pores, each of which is placed in +the lower end of an oblong, lanceolate, longitudinal furrow; collar +composed of fifteen to twenty such furrows. Abdomen inflated, with four to +six transverse rows of circular pores, and with a coronal of nine +triangular, divergent feet, longer than the collar. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.03, _c_ 0.06; +breadth, _a_ 0.03, _b_ 0.06, _c_ 0.09. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +5. _Clathrocyclas puella_, Haeckel. + + _Podocyrtis puella sinensis_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 82, Taf. xiv. fig. 3. + +Shell subconical, with two indistinct strictures. Length of the three +joints = 1 : 1 : 2, breadth = 1 : 2 : 3. Cephalis hemispherical, with a +pyramidal horn of twice the length. Pores subregular, circular, +quincuncial, in the dilated abdomen (with four to five transverse rows), +twice to three times as large as in the short thorax (with two to three +rows). Coronal of the wide peristome with fifteen to twenty short, +triangular, divergent feet, about as long as the cephalis. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.02, _c_ 0.04; +breadth, _a_ 0.02, _b_ 0.04, _c_ 0.06. + +_Habitat._--Fossil in Barbados. + + +6. _Clathrocyclas domina_, Haeckel. + + _Podocyrtis domina sinensis_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 82, Taf. xiv. fig. 4. + +Shell subconical, with two slight strictures. Length of the three joints = +1 : 2 : 4, breadth = 1 : 3 : 4. Cephalis ovate, with a conical horn of the +same length (and sometimes with some little accessory thorns at its base). +Pores subregular, circular, quincuncial, in the dilated abdomen (with six +to eight transverse rows), twice to four times as large as in the +hemispherical thorax (with four to six rows). Coronal of the wide peristome +with nine to twelve short, triangular, divergent feet, half as long as the +cephalis (in Ehrenberg's figure incomplete). + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.08; +breadth, _a_ 0.02, _b_ 0.06, _c_ 0.08. + +_Habitat._--Central Pacific, Stations 263 to 268, depth 2650 to 3000 +fathoms; also fossil in Barbados. + + + +{1388}Subgenus 2. _Clathrocycloma_, Haeckel. + +_Definition._--Shell flatly conical, often widely campanulate, or nearly +discoidal. Cephalis commonly with two or more horns. + + +7. _Clathrocyclas alcmenae_, n. sp. (Pl. 59, fig. 6). + +Shell conical, with two indistinct strictures. Length of the three joints = +2 : 10 : 1, breadth = 2 : 12 : 14. Cephalis hemispherical, with two +divergent, pyramidal horns; frontal horn as long as the cephalis, occipital +horn of twice the length. Thorax conical, with large hexagonal meshes, +increasing gradually in size towards the short abdomen, which is +represented only by a single circular girdle of small, square, abdominal +pores. Coronal of the peristome with twenty to thirty triangular, +divergent, nearly horizontal feet, as long as the cephalis. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.1, _c_ 0.01. +_breadth_, _a_ 0.02, _b_ 0.12, _c_ 0.14. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +8. _Clathrocyclas europae_, n. sp. (Pl. 59, figs. 11, 12). + +Shell conical, almost of the same form as the preceding nearly allied +species, differing from it in the concave (not straight) outline of the +flatter conical thorax, in the more rounded form of its pores, and in the +subspherical form of the cephalis, bearing only a single conical horn of +the same length. Length of the three joints = 2 : 8 : 1, breadth = +2 : 12 : 14. In fig. 11 the cephalis is broken off, so that the four +cortinar pores are visible (two smaller jugular and two larger cardinal +pores, separated by two coracal beams). + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.08, _c_ 0.01. +_breadth_, _a_ 0.02, _b_ 0.12, _c_ 0.14. + +_Habitat._--Mediterranean, Corfu (Haeckel), surface. + + +9. _Clathrocyclas semeles_, n. sp. (Pl. 58, fig. 5). + +Shell conical-campanulate, with two distinct strictures. Length of the +three joints = 2 : 8 : 1, breadth = 2 : 8 : 10. Cephalis hemispherical, +with three divergent, conical horns (the caudal horn, directed downwards, +much longer than the occipital and frontal horns). Pores of the thorax +large, roundish. Abdomen (as in the two preceding species) with only a +single circle of forty to fifty small square pores. Coronal with about the +same number of short, triangular, almost horizontally divergent feet. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.08, _c_ 0.01. +_breadth_, _a_ 0.02, _b_ 0.08, _c_ 0.1. + +_Habitat._--Central Pacific, Station 271, surface. + + +10. _Clathrocyclas danaes_, n. sp. (Pl. 59, figs. 13, 14). + +Shell flatly conical, with straight outline (as in _Clathrocyclas +alcmenae_, Pl. 59, fig. 6). Length of the three joints = 1 : 5 : 1, breadth += 2 : 8 : 1. Cephalis hemispherical, with a single, short, conical, +{1389}oblique horn (broken off in the specimen figured). Pores of the +thorax polygonal, increasing gradually in size towards the girdle (in three +to four circles.) Abdomen nearly horizontally expanded with two rows of +pores, the inner with very small and numerous square pores, the outer with +twenty to thirty much larger quadrangular pores. Coronal of the peristome +with the same number of short, divergent feet, alternating with the larger +pores. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.1, _c_ 0.02; +breadth, _a_ 0.04, _b_ 0.15, _c_ 0.2. + +_Habitat._--North Atlantic, Canary Islands (Lanzerote), Station 354, +surface. + + +11. _Clathrocyclas jonis_, n. sp. (Pl. 59, fig. 9). + +Shell campanulate, with two slight strictures. Length of the three joints = +1 : 5 : 2, breadth = 1 : 6 : 8. Cephalis small, hemispherical, with two +divergent, conical horns of nearly equal length. Pores of the thorax +polygonal, increasing in size towards the girdle; in the upper half filled +up by an extremely fine and delicate cobweb-like network. Abdomen with two +rows of pores, of the same shape as in the preceding species, also with +equal coronal. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.1, _c_ 0.03; +breadth, _a_ 0.02, _b_ 0.12, _c_ 0.16. + +_Habitat._--Central Pacific, Station 274, surface. + + +12. _Clathrocyclas latonae_, n. sp. (Pl. 59, fig. 7). + +Shell campanulate, very similar to the preceding species, but flatter and +different in the larger cephalis, bearing only a single oblique horn. All +the polygonal pores of the thorax are filled out by delicate cobweb-like +network. Length of the three joints = 1 : 3 : 1, breadth = 1 : 4 : 6. +Abdomen with three circular rows of quadrangular pores; first very small +and numerous, second of median size, third very large. Coronal with thirty +to forty short triangular feet. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.08, _c_ 0.03; +breadth, _a_ 0.03, b 0.12, c 0.18. + +_Habitat._--Tropical Atlantic, Station 325, surface. + + +13. _Clathrocyclas coscinodiscus_, n. sp. (Pl. 58, figs. 3, 4). + +Shell flatly campanulate, with two distinct strictures. Length of the three +joints = 1 : 5 : 2, breadth = 1 : 8 : 10. Cephalis hemispherical, with two +divergent, pyramidal horns of the same length. Thorax with concave outline, +with numerous hexagonal pores, gradually increasing in size towards the +girdle, except the outermost row (inside the girdle), which is composed of +very small, square pores. Abdomen (outside the girdle) with three rows of +pores; first with small, second with median, third with large pores. +Coronal with eighty to one hundred short, divergent feet. + +_Dimensions._--Length of the three joints, _a_ 0.02, b 0.1, _c_ 0.03; +breadth, _a_ 0.025, b 0.16, c 0.2. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +{1390}14. _Clathrocyclas cassiopeiae_, n. sp. (Pl. 59, fig. 5). + +Shell flatly campanulate, with two slight strictures. Length of the three +joints = 2 : 4 : 3, breadth = 2 : 6 : 8. Cephalis ovate, thorny, with a +pyramidal horn of the same length, and several smaller accessory horns. +Thorax smooth, with irregular, polygonal pores of nearly equal size. +Abdomen spiny, with three to four irregular rows of similar pores. Coronal +with sixty to ninety or more irregularly and obliquely divergent feet, +little larger than the abdominal spines. + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.08, _c_ 0.06; +breadth, _a_ 0.03, _b_ 0.12, _c_ 0.16. + +_Habitat._--Indian Ocean, Madagascar, Rabbe, surface. + + + +Genus 607. _Lamprocyclas_,[224] Haeckel, 1881, Prodromus, p. 434. + +_Definition._--#Theophormida# (vel Tricyrtida multiradiata aperta) with a +double corona of solid terminal feet around the mouth. No ribs in the +shell-wall. + +The genus _Lamprocyclas_ differs from _Calocyclas_, its ancestral form, in +the duplication of the terminal corona. Usually the feet or teeth of the +lower corona are convergent and curved inwards, whilst the teeth of the +upper corona are divergent and curved outwards. Sometimes above the latter +a third corona begins to be developed. The whole shell is more or less +conical, very thick-walled, with a large and stout apical horn. + + + +Subgenus 1. _Lamprocyclia_, Haeckel. + +_Definition._--Feet of the peristome simple, not branched. + + +1. _Lamprocyclas nuptialis_, n. sp. (Pl. 74, fig. 15). + +Shell campanulate, nearly smooth, with two slight strictures. Length of the +three joints = 1 : 2 : 2, breadth = 1 : 3 : 4. Cephalis ovate, with a very +large, three-sided prismatic horn, nearly as long as the shell. Thorax and +abdomen gradually dilated, with regular, circular, double-edged pores. +Outer coronal of the peristome with twelve to fifteen divergent feet, inner +with as many subvertical, triangular, little curved feet, about as long as +the cephalis. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.06, _c_ 0.06; +breadth, _a_ 0.03, _b_ 0.09, _c_ 0.12. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +2. _Lamprocyclas maritalis_, n. sp. (Pl. 74, figs. 13, 14). + +Shell campanulate, very similar to the preceding species in form and +fenestration, but not so slender and with different peristome. Length of +the three joints = 4 : 5 : 6, breadth = 4 : 10 : 13. Cephalis subspherical, +with a very stout, pyramidal horn of twice the length, the edges of which +are {1391}spirally convoluted. Outer coronal of the peristome with twelve +to fifteen short, divergent feet, inner with as many convergent, longer +feet. + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.05, _c_ 0.06; +breadth, _a_ 0.04, _b_ 0.1, _c_ 0.13. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +3. _Lamprocyclas deflorata_, n. sp. (Pl. 74, fig. 10). + +Shell ovate, smooth, with deep collar, but indistinct lumbar stricture; +very similar to the two preceding species, but with different horn and +peristome. Length of the three joints = 3 : 5 : 8, breadth = 3 : 10 : 13. +Cephalis subspherical, with a pyramidal horn of twice the length, the three +faces of which are deeply concave. Thoracic pores half as large as the +abdominal, both subregular, double-edged. Outer coronal of the wide +peristome with nine short, triangular, subvertical feet, inner with nine +larger, horizontal feet, lying in the plane of the wide mouth. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.05, _c_ 0.08; +breadth, _a_ 0.03, _b_ 0.1, _c_ 0.13. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +4. _Lamprocyclas saltatricis_, n. sp. (Pl. 74, fig. 16). + +Shell conical, rough, with two slight strictures. Length of the three +joints = 2 : 2 : 3, breadth = 1 : 4 : 6. Cephalis ovate, with a large, +prismatic horn, half as long as the shell. Pores subregular, circular, not +double-edged, three times as broad in the inflated abdomen as in the +hemispherical thorax. Outer coronal of the wide peristome with twelve to +fifteen divergent feet, inner with fifteen to twenty conical feet, which +are curved inwards nearly horizontally. + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.05, _c_ 0.07; +breadth, _a_ 0.025, _b_ 0.1, _c_ 0.15. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +5. _Lamprocyclas reginae_, n. sp. (Pl. 74, figs. 11, 12). + +Shell campanulate, with two slight strictures. Length of the three joints = +2 : 3 : 3, breadth = 2 : 5 : 6. Cephalis subcylindrical, with about fifteen +longitudinal rows of circular pores, separated by prominent, parallel +crests, and with a very large sword-like horn, nearly as long as the shell. +Thorax hemispherical, smooth, with elegant, circular, hexagonally-framed +pores. Abdomen dilated, with similar but larger pores, armed with +hook-shaped spines. The two inferior rows of these hooks form the double +coronal of the peristome; the feet of the outer are curved downwards, of +the inner inwards. + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.06, _c_ 0.06; +breadth, _a_ 0.04, _b_ 0.1, _c_ 0.12. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + +6. _Lamprocyclas aegles_, Haeckel. + + _Podocyrtis aegles_, Ehrenberg, 1854, Mikrogeol., Taf. xxxv. B. B iv. + fig. 18. + +Shell campanulate, conical, thorny, with two deep strictures. Length of the +three joints = 3 : 5 : 5, breadth = 3 : 8 : 11. Cephalis ovate, with a +stout, three-sided prismatic horn of twice the {1392}length. Pores +subregular, circular, twice as broad in the inflated abdomen as in the +campanulate thorax, and four times as broad as in the cephalis. Outer +coronal of the wide peristome with fifteen to twenty conical, divergent +feet, inner coronal with a smaller number of vertical, parallel, divergent +feet. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.05, _c_ 0.05; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.11. + +_Habitat._--North Atlantic, depth 1400 fathoms (Berrymann). + + + +Subgenus 2. _Lamprocycloma_, Haeckel. + +_Definition._--Feet of the peristome forked or branched. + + +7. _Lamprocyclas bajaderae_, n. sp. + +Shell campanulate, very similar to the preceding species, but with stronger +spines on the abdomen and with different peristome. Length of the three +joints = 2 : 2 : 3, breadth = 2 : 6 : 8. Cephalis equal to that of +_Lamprocyclas maritalis_ (Pl. 74, figs. 13, 14). Outer coronal of the +peristome with fifteen to twenty divergent, pyramidal feet, half as long as +the horn; inner coronal with as many longer, vertical feet, which are +irregularly forked or branched. + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.04, _c_ 0.06; +breadth, _a_ 0.04, _b_ 0.12, _c_ 0.16. + +_Habitat._--South Pacific, Station 298, depth 2225 fathoms. + + + +Genus 608. _Diplocyclas_,[225] Haeckel, 1881, Prodromus, p. 434. + +_Definition._--#Theophormida# (vel Tricyrtida multiradiata aperta) with a +double corona of radial solid feet, an upper around the lumbar stricture, a +lower around the mouth. No ribs in the shell-wall. + +The genus _Diplocyclas_ differs from all the other Theophormida in the +possession of a double coronal of radial teeth, an upper between thorax and +abdomen, and a lower around the terminal mouth of the latter; it may be +regarded as an _Anthocyrtis_, which has formed an abdomen, and repeated the +terminal armature. The cephalis bears a single or double apical horn. + + +1. _Diplocyclas bicorona_, n. sp. (Pl. 59, fig. 8). + +Shell slender, campanulate. Length of the three joints = 1 : 3 : 2, breadth += 1 : 4 : 4. Cephalis subspherical, with two divergent horns; the occipital +of the same length and forked, the frontal shorter and simple. Thorax +campanulate, with six to eight transverse rows of double-edged roundish +pores of increasing size. Abdomen cylindrical, with three transverse rows +of large {1393}polygonal pores, and a terminal row of very small square +pores. Lumbar and terminal coronals of similar shape, each with twenty to +thirty short divergent feet. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.04; +breadth, _a_ 0.025, _b_ 0.08, _c_ 0.08. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +2. _Diplocyclas bicincta_, n. sp. + +Shell campanulate, in general of the same form as, and similar fenestration +to, the preceding species but not so slender, and with different +proportions. Length of the three joints = 1 : 4 : 2, breadth = 2 : 5 : 5. +Cephalis hemispherical, with a single, conical, simple horn. Pores of the +thorax hexagonal, of increasing size (in eight to ten transverse rows). +Abdomen with smaller square pores (in four to six rows). The two coronals +of the same shape as in Pl. 59, fig. 8. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.08, _c_ 0.04; +breadth, _a_ 0.04, _b_ 0.1, _c_ 0.1. + +_Habitat._--North Pacific, Station 253, depth 3125 fathoms. + + +3. _Diplocyclas bizonalis_, n. sp. + +Shell subconical, with indistinct collar and distinct lumbar stricture. +Length of the three joints = 1 : 2 : 3, breadth = 1 : 3 : 4. Cephalis +hemispherical, with two divergent conical horns of equal size. Thorax +conical, with small, irregular, double-edged pores, and a terminal corona +of about nine very large pores. Abdomen truncate, conical, with three to +four transverse rows of roundish, quadrangular, very large pores. Lumbar +and terminal coronals of similar shape, each with twelve to fifteen +triangular divergent feet. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.06; +breadth, _a_ 0.02, _b_ 0.06, _c_ 0.08. + +_Habitat._--South Pacific, Station 295, depth 1500 fathoms. + + + +Subfamily 2. THEOPHAENIDA, Haeckel, 1881, Prodromus, p. 437. + +_Definition._--#Phormocyrtida# with the basal mouth of the shell +fenestrated (vel Tricyrtida multiradiata clausa). + + + +Genus 609. _Hexalatractus_,[226] n. gen. + +_Definition._--#Theophaenida# (vel Tricyrtida multiradiata clausa) with six +lateral wings on the abdomen. + +The genus _Hexalatractus_, and the following genus _Theophaena_, represent +together the small subfamily Theophaenida, or those Tricyrtida in which the +terminal mouth of the shell is closed by lattice-work, and six or nine +lateral apophyses indicate a multiradiate structure. The shell is more or +less ovate or spindle-shaped, tapering towards {1394}both poles, and +resembles greatly the triradiate _Rhopalocanium_. It may be derived from +the latter by interpolation of three secondary or interradial wings between +the three primary or perradial apophyses. + + +1. _Hexalatractus sexalatus_, n. sp. + +Shell ovate, smooth, with two distinct strictures, length of the three +joints = 3 : 6 : 9, breadth = 4 : 9 : 8. Cephalis subspherical, with a +pyramidal horn of twice the length. Thorax campanulate; abdomen inversely +conical; both with subregular, circular pores. Six divergent wings arise, +beginning from the collar stricture, from the upper half of the shell, with +broad triangular base; they are little curved downwards, with the convexity +outside, and gradually tapering towards the distal end; the latter lies in +the same horizontal plane as the basal apex of the abdomen. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.06, _c_ 0.09; +breadth, _a_ 0.04, _b_ 0.09, _c_ 0.08. + +_Habitat._--Central Pacific, Stations 263, depth 2650 fathoms. + + +2. _Hexalatractus fusiformis_, n. sp. (Pl. 68, fig. 13). + +Shell rough, nearly spindle-shaped, with sharp collar and slight lumbar +stricture. Length of the three joints = 2 : 5 : 12, breadth = 3 : 8 : 7. +Cephalis hemispherical, with a conical horn of the same length. Thorax +hemispherical with regular, circular, hexagonally-framed pores. Abdomen +inversely conical, with irregular, roundish pores. From the upper half of +the abdomen arise, with broad triangular base, six divergent wings, which +are nearly straight, and slightly fenestrated at the base; their conical +distal ends do not reach the horizontal plane, in which the basal apex of +the abdomen lies. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.05, _c_ 0.12; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.07. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + + +Genus 610. _Theophaena_,[227] Haeckel, 1881, Prodromus, p. 437. + +_Definition._--#Theophaenida# (vel Tricyrtida multiradiata clausa) with +nine lateral wings on the abdomen. + +The genus _Theophaena_ differs from the preceding six-radiate +_Hexalatractus_ in the possession of nine lateral wings, and may be derived +from the triradiate _Rhopalocanium_ by interpolation of six secondary wings +between the three primary apophyses. + + +1. _Theophaena corona_, n. sp. (Pl. 70, fig. 12). + +Shell rough, nearly spindle-shaped, with two sharp strictures. Length of +the three joints = 4 : 9 : 16, breadth = 5 : 12 : 10. Cephalis +hemispherical, very thick-walled, with a conical horn of {1395}the same +length; both covered with numerous small dimples and spinules. Thorax +campanulate; abdomen inversely conical; both with regular, circular pores. +Thorax with nine thin curved ribs, which in the upper half of the abdomen +arise as nine large feet, which are strongly compressed and curved (with +the convexity outwards); their distal ends form nine ovate spinulate cones, +and lie in the same horizontal plane as the basal apex of the abdomen. + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.09, _c_ 0.16; +breadth, _a_ 0.05, _b_ 0.12, _c_ 0.1. + +_Habitat._--Indian Ocean, Madagascar (Rabbe), surface. + + +2. _Theophaena nonaria_, n. sp. + +Shell thorny, ovate, with two slight strictures. Length of the three joints += 1 : 4 : 5, breadth = 1 : 5 : 4. Cephalis subspherical, with a conical +horn of half the length. Thorax subspherical, with regular, circular pores +and conical spines. Abdomen ovate, smooth, with irregular, roundish pores. +In the upper half of the thorax descend nine straight, little divergent +ribs, which in the lower half become free, and represent nine slender, +conical wings; their distal ends do not reach the horizontal plane in which +the basal end of the abdomen lies. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.12, _c_ 0.15; +breadth, _a_ 0.03, _b_ 0.14, _c_ 0.12. + +_Habitat._--South of Australia, Station 160, surface. + + + +Family LXVII. #THEOCYRTIDA#, n. fam. + + _Theocorida et Theocapsida_, Haeckel, 1881, Prodromus, pp. 434, 436. + +_Definition._--#Tricyrtida# eradiata. #Cyrtoidea# with a three-jointed +shell, divided by two transverse constrictions into cephalis, thorax, and +abdomen, without radial apophyses. + +The family #Theocyrtida#, composed of the Theocorida and Theocapsida of my +Prodromus, comprises those #Cyrtoidea# in which the lattice-shell is +three-jointed, and bears no external radial apophyses. The two subfamilies +differ in the shape of the terminal mouth, which in the Theocorida is a +simple wide opening, in the Theocapsida closed by a lattice-plate. The +phylogenetic origin of the Theocyrtida may be found either in the +Podocyrtida or in the Sethocyrtida; they may have been derived from the +former by reduction and loss of the three primary apophyses, or from the +latter by development of an abdomen. + +The number of species in this group is very large, and many belong to the +most common and widely distributed #Cyrtoidea#. A great number of living +and fossil species have already been described by Ehrenberg, the majority +being disposed in his genera _Lithocampe_ and _Eucyrtidium_. + +The number of genera, however, is comparatively small, and their +distinction difficult, since the form of the shell presents no striking +differences. + +{1396}It exhibits all possible passages, from a flatly expanded or nearly +discoidal form with a wide open mouth, to a conical or cylindrical, and by +constriction of the terminal mouth to an ovate or spindle-shaped form. By +complete closure of the mouth the Theocapsida arise. In some genera +remarkable traces of the original triradial structure are preserved. The +most interesting of these forms is _Axocorys_, with an internal axial +columella, which bears a number of verticils, each with three radial +branches. + +_Synopsis of the Genera of Theocyrtida._ + + ------------------------------------------------------------------------- + I. Subfamily Theocorida. + Terminal mouth of the abdomen a simple wide opening. + -------------------- + Abdomen gradually dilated towards the wide open mouth. + ------------------------------------------------------------------------- + Abdomen flatly { With horn, 611. _Theocalyptra_. + expanded, { + discoidal. { No horn, 612. _Cecryphalium_. + + { One horn, 613. _Theoconus_. + Abdomen conical. { + { Two or more horns, 614. _Lophoconus_. + ------------------------------------------------------------------------- + Abdomen cylindrical, of nearly equal breadth throughout its whole length. + Mouth truncate. + ------------------------------------------------------------------------- + { Thorax and abdomen + A single apical horn { of equal breadth, 615. _Theocyrtis_. + on the cephalis. { + { Thorax much broader than + { the tubular abdomen, 616. _Theosyringium_. + + Two horns or a bunch of horns on the ephalis, 617. _Lophocyrtis_. + + No horn on the cephalis, 618. _Tricolocampe_. + ------------------------------------------------------------------------- + Abdomen ovate or inversely conical. Mouth more or less constricted. + ------------------------------------------------------------------------- + { Shell-cavity without an + A single apical horn { internal columella, 619. _Theocorys_. + on the cephalis. { + { Shell-cavity with an + { axial columella, 620. _Axocorys_. + + Two horns or a bunch of horns on the + cephalis, 621. _Lophocorys_. + + No horn on the cephalis, 622. _Theocampe_. + ------------------------------------------------------------------------- + II. Subfamily Theocapsida. + Terminal mouth closed by a lattice-plate. + ------------------------------------------------------------------------- + No latticed septum { An apical horn, 623. _Theocapsa_. + between thorax and { + abdomen. { No horn on the cephalis, 624. _Tricolocapsa_. + + A complete latticed septum between thorax + and abdomen, 625. _Phrenocodon_. + + + +Subfamily 1. THEOCORIDA, Haeckel, 1881, Prodromus, p. 434. + +_Definition._--#Theocyrtida# with the basal mouth of the shell open (vel +Tricyrtida eradiata aperta). + + + +{1397}Genus 611. _Theocalyptra_,[228] Haeckel, 1881, Prodromus, p. 434. + +_Definition._--#Theocorida# (vel Tricyrtida eradiata aperta) with discoidal +or flatly expanded abdomen. Cephalis with a single apical horn, or with two +divergent horns. + +The genus _Theocalyptra_, and the following closely allied genus +_Cecryphalium_, differ from all the other Theocorida in the flattened form +of the cap-shaped or nearly discoidal shell. The abdomen specially is quite +flat, often horizontally expanded, and like the marginal brim of a flat +hat. They may be derived from the Dicyrtida _Sethocephalus_ by the +development of an abdomen, or from _Corocalyptra_ by loss of the collar +wings. The network is usually very delicate, as in the latter. The cephalis +of _Theocalyptra_ bears one or two horns. + + +1. _Theocalyptra veneris_, n. sp. + +Shell flatly campanulate, very delicate and fragile, very similar to +_Eucecryphalus agnesae_ (Pl. 59, fig. 3), but without collar spines. Length +of the three joints = 1 : 4 : 2, breadth = 1 : 7 : 9. Cephalis +hemispherical, with a single bristle-shaped horn of twice the length. +Thorax subconical, separated from the flatter abdomen by a deep stricture, +with thin bars, and large, subregular, hexagonal meshes, increasing in size +towards the smooth mouth-edge. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.07, _c_ 0.04; +breadth, _a_ 0.025, _b_ 0.15, _c_ 0.1. + +_Habitat._--Cosmopolitan; Atlantic, Indian, Pacific, many stations, +surface. + + +2. _Theocalyptra orci_, Haeckel. + + _Halicalyptra orci_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 293, Taf. x. figs. 9, 10. + +Shell flatly campanulate, very similar to the preceding species in general +form and fenestration, but flatter and smaller, with different proportions. +Length of the three joints = 7 : 2 : 1, breadth = 1 : 6 : 8. Cephalis +hemispherical, very small, with two divergent, bristle-shaped horns of the +same length. Abdomen nearly horizontally expanded. + +_Dimensions._--Length of the three joints, _a_ 0.015, _b_ 0.04, _c_ 0.01; +breadth, _a_ 0.02, _b_ 0.12, _c_ 0.16. + +_Habitat._--Indian Ocean, Zanzibar, depth 2200 fathoms (Pullen). + + +3. _Theocalyptra discoides_, Haeckel. + + _Cycladophora discoides_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 68, Taf. xviii. fig. 4. + +Shell flatly campanulate, similar to the two preceding species, but not so +delicate, with thicker bars, and roundish, not hexagonal meshes. Length of +the three joints = 1 : 2 : 2, breadth = 3 : 6 : 9. {1398}Cephalis large, +trilobed, with a short, oblique horn of half the length. Thorax +campanulate, conical, separated from the abdomen by a circle of smaller +pores and a deep stricture. Abdomen flat, discoidal, with three circles of +larger pores. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.04; +breadth, _a_ 0.06, _b_ 0.12, _c_ 0.18. + +_Habitat._--Fossil in Barbados. + + +4. _Theocalyptra cornuta_, Haeckel. + + _Carpocanium cornutum_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 287, Taf. ii. fig. 9. + + _Halicalyptra cornuta_, Bailey, 1856, Amer. Journ. Sci. and Arts, vol. + xxii. p. 5, pl. i. figs. 13, 14. + + _Lophophaena cornuta_, Haeckel, 1862, Monogr. d. Radiol., p. 299. + +Shell campanulate-conical, with two sharp strictures. Length of the three +joints = 1 : 3 : 1, breadth = 1 : 4 : 5. Cephalis subspherical, with two +stout, pyramidal, divergent horns of twice the length. Thorax campanulate, +with eight to ten transverse rows of roundish or nearly square pores, +increasing in size towards the abdomen, which is flatly expanded, nearly +discoidal, separated by a circle of smaller pores; the last circle of pores +(on the margin) is larger. + +_Dimensions._--Length of the three joints, _a_ 0.025, _b_ 0.09, _c_ 0.03; +breadth, _a_ 0.03, _b_ 0.12, _c_ 0.16. + +_Habitat._--Arctic Ocean, Kamtschatka (Bailey), Greenland (Ehrenberg). + + + +Genus 612. _Cecryphalium_,[229] Haeckel, 1881, Prodromus, p. 434. + +_Definition._--#Theocorida# (vel Tricyrtida eradiata aperta) with discoidal +or flatly expanded abdomen. Cephalis without horn. + +The genus _Cecryphalium_ has the same flat, conical, or nearly discoidal +shell as the preceding _Theocalyptra_, its ancestral genus, but differs +from it in the complete absence of horns on the cephalis. + + +1. _Cecryphalium lamprodiscus_, n. sp. (Pl. 58, fig. 2). + +Shell flatly conical, with two slight strictures. Length of the three +joints = 1 : 3 : 2, breadth = 1 : 7 : 11. Cephalis roundish, very small. +Thorax conical, with straight lateral outline; its pores irregular, +polygonal, increasing in size towards the girdle. Abdomen little flatter +than the thorax, forming its direct prolongation, with five to six +circular, concentric rows of pores; the first row formed by sixty to eighty +very large, oblongish, quadrangular pores, the second row by very small, +the third again by larger pores; the outmost rows by very small and +numerous pores. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.04; +breadth, _a_ 0.02, _b_ 0.14, _c_ 0.22. + +_Habitat._--Central Pacific, Station 272, surface. + + +{1399}2. _Cecryphalium sestrodiscus_, n. sp. (Pl. 58, fig. 1). + +Shell very flat, subconical, nearly discoidal, with two distinct +strictures. Length of the three joints = 1 : 2 : 1, breadth = 1 : 8 : 10. +Cephalis kidney-shaped, very small. Thorax flat, campanulate, with curved +lateral outline; its pores irregular, polygonal, increasing in size towards +the girdle. Abdomen horizontally expanded, like the brim of a hat, with +five to six concentric, circular rows of pores, the pores of the inner rows +twice to three times as large as those of the outer rows. (The inner circle +of large, oblongish, quadrangular pores, characteristic of the preceding +species, is here divided into three concentric rings by two circular +hoops.) + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.02; +breadth, _a_ 0.02, _b_ 0.15, _c_ 0.2. + +_Habitat._--Central Pacific, Station 274, surface. + + + +Genus 613. _Theoconus_,[230] n. gen. + +_Definition._--#Theocorida# (vel Tricyrtida eradiata aperta) with conical +abdomen, gradually dilated towards the wide open mouth. Cephalis with a +single horn. + +The genus _Theoconus_, and the following closely allied _Lophoconus_, +differ from the other Theocorida in the conical or campanulate form of the +shell; the abdomen is a truncated cone, gradually dilated towards the +terminal mouth. The latter is usually truncated, widely open, sometimes +with a slightly constricted peristome. The cephalis of _Theoconus_ bears a +single apical horn. + + + +Subgenus 1. _Theocorax_, Haeckel. + +_Definition._--Pores of the thorax and of the abdomen of nearly equal size +and similar form. + + +1. _Theoconus zancleus_, Haeckel. + + _Eucyrtidium zancleum_, J. Mueller, 1858, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 41, Taf. vi. figs. 1-3. + + _Eucyrtidium zancleum_, Haeckel, 1862, Monogr. d. Radiol., p. 321. + +Shell bell-shaped, nearly conical, smooth. Length of the three joints = +1 : 3 : 4, breadth = 1 : 4 : 6. Cephalis nearly spherical, with a stout, +straight, pyramidal horn of the same length. Thorax hemispherical. Abdomen +gradually increasing in breadth towards the wide truncated mouth. Pores in +all three joints nearly of the same shape, circular, regular, four times as +broad as the thin bars. + +_Dimensions._--Length of the three joints, _a_ 0.027, _b_ 0.08, _c_ 0.1; +breadth, _a_ 0.03, _b_ 0.12, _c_ 0.18. + +_Habitat._--Mediterranean (Messina, Naples, Nice, &c.). + + +{1400}2. _Theoconus aegaeus_, Haeckel. + + _Eucyrtidium aegaeum_, Ehrenberg, 1858, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 31; Mikrogeol., 1854, Taf. xxxv. a, xix. a, fig. 5. + + _Eucyrtidium aegaeum_, Haeckel, 1862, Monogr. d. Radiol., p. 329. + +Shell flatly bell-shaped, nearly conical. Length of the three joints = +2 : 5 : 3; breadth = 1 : 7 : 8. Cephalis ovate, with a stout, straight, +pyramidal horn of the same length. Thorax flat, bell-shaped. Abdomen with +increasing breadth towards the wide truncated mouth. Pores in all three +joints nearly of the same shape, regular, circular, three times as broad as +the bars. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.05, _c_ 0.03; +breadth, _a_ 0.016, _b_ 0.07, _c_ 0.08. + +_Habitat._--Mediterranean (Coast of Greece and Sicily), surface. + + +3. _Theoconus zanguebaricus_, Haeckel. + + _Eucyrtidium zanguebaricum_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 293, Taf. ix. fig. 22. + +Shell bell-shaped. Length of the three joints = 1 : 2 : 1, breadth = +1 : 3 : 4. Cephalis ovate, with a straight, pyramidal horn of half the +length. Thorax hemispherical, without collar stricture, but with evident +girdle stricture. Abdomen dilated towards the wide truncated mouth. Pores +regular, hexagonal, of nearly equal size and form, four to six times as +broad as the thin bars. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.06, _c_ 0.03; +breadth, _a_ 0.024, _b_ 0.09, _c_ 0.11. + +_Habitat._--Indian Ocean (off Zanzibar), Pullen, depth 2200 fathoms. + + +4. _Theoconus campanulatus_, Haeckel. + + ? _Eucyrtidium campanulatum_, Ehrenberg, 1858, Monatsber. d. k. preuss. + Akad. d. Wiss. Berlin, p. 241. + + _Eucyrtidium campanulatum_, Haeckel, 1862, Monogr. d. Radiol., p. 329. + +Shell bell-shaped, smooth. Length of the three joints = 2 : 3 : 7, breadth += 3 : 7 : 10. Cephalis small, spherical, with a short, conical, oblique +horn of the same length. Thorax hemispherical, with an external girdle +stricture, prolonged into the truncated, barrel-shaped abdomen, which is a +little constricted at the very wide mouth. Pores small and very numerous, +regular, circular, twice to three times as broad as the bars. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.03, _c_ 0.07; +breadth, _a_ 0.03, _b_ 0.07, _c_ 0.1. + +_Habitat._--North Atlantic, Station 352, surface. + + +5. _Theoconus orthoconus_, n. sp. + +Shell perfectly conical, smooth. Length of the three joints = 1 : 2 : 3, +breadth = 1 : 2 : 4. Cephalis hemispherical, with a strong, straight, +conical horn of the same length. Thorax conical, without external girdle +stricture, prolonged into the truncated, conical abdomen, which is +gradually {1401}dilated into a very wide mouth. Pores small, of nearly +equal size and similar form, of the same breadth as the bars. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.06, _c_ 0.09; +breadth, _a_ 0.03, _b_ 0.06, _c_ 0.12. + +_Habitat._--Cosmopolitan; Atlantic, Pacific; many stations, at different +depths. + + + +Subgenus 2. _Theocorbis_, Haeckel. + +_Definition._--Pores of the thorax and of the abdomen of different sizes or +dissimilar forms. + + +6. _Theoconus jovis_, n. sp. (Pl. 69, fig. 4). + +Shell bell-shaped, nearly conical. Length of the three joints = 5 : 6 : 7, +breadth = 4 : 10 : 14. Cephalis nearly cylindrical, large, little curved, +with a very large, oblique, pyramidal horn, as long as the two first joints +together. Thorax and the broader abdomen irregularly bell-shaped, dilated +towards the wide mouth. Pores circular, somewhat irregularly disposed, +gradually increasing in size towards the mouth. + +_Dimensions._--Length of the three joints, _a_ 0.05, _b_ 0.06, _c_ 0.07; +breadth, _a_ 0.04, _b_ 0.1, _c_ 0.14. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +7. _Theoconus junonis_, n. sp. (Pl. 69, fig. 7). + +Shell nearly conical. Length of the three joints = 4 : 5 : 8, breadth = +3 : 8 : 11. Cephalis ovate, with a large apical opening at the base of the +vertical compressed horn, which has about the same length. Thorax and the +broader abdomen together conical, gradually dilated towards the wide mouth. +Thorax with a bosom-like protuberance on one side. Pores circular, +gradually increasing in size. + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.05, _c_ 0.08; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.11. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +8. _Theoconus longicornis_, n. sp. + +Shell conical, thorny. Length of the three joints = 1 : 2 : 4, breadth = +1 : 3 : 6. Cephalis nearly spherical, with a very large, cylindrical, +perpendicular, straight horn, once and a half to twice as long as the whole +shell. Thorax conical. Abdomen nearly hemispherical, with wide open mouth. +Pores circular, four to six times as broad in the thick-walled spiny +abdomen as in the thin-walled rough thorax. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.06, _c_ 0.12; +breadth, _a_ 0.03, _b_ 0.09, _c_ 0.18. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms; also fossil +in Barbados. + + +{1402}9. _Theoconus ampullaceus_, Haeckel. + + _Lithocampe ampullacea_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 66, Taf. iv. fig. 1. + + _Theocorys ampullacea_, Haeckel, 1881, Prodromus, p. 434. + +Shell bell-shaped, nearly conical, thorny. Length of the three joints = +3 : 4 : 10; breadth = 4 : 8 : 15. Cephalis subspherical, with a stout +lateral horn of the same length. Thorax hemispherical, rough. Abdomen +subspherical, widely truncated at both poles, spiny. Pores regular, +circular, three to four times as broad in the thick-walled abdomen as in +the thin-walled thorax. (Differs from the similar preceding species in the +smaller horn and the two deeper strictures of the shell.) + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.04, _c_ 0.1; +breadth, _a_ 0.04, _b_ 0.08, _c_ 0.15. + +_Habitat._--Fossil in Barbados. + + +10. _Theoconus amplus_, Haeckel. + + ? _Podocyrtis ampla_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 80, Taf. xvi. fig. 7. + + ? _Podocyrtis ampla_, Buetschli, 1882, Zeitschr. f. wiss. Zool., vol. + xxxvi. p. 539, Taf. xxxiii. fig. 16. + + ? _Eucyrtidium amplum_, Ehrenberg, 1873, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, p. 248. + +Shell conical, smooth, with two broad internal annular septa. Length of the +three joints = 1 : 3 : 4, breadth = 1 : 4 : 5. Cephalis subspherical, with +a very large, straight, conical horn of the same breadth, which is as long +as the conical thorax. Pores regular, circular, twice as broad in the +truncate, gradually dilated abdomen as in the thorax. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.09, _c_ 0.12; +breadth, _a_ 0.03, _b_ 0.12, _c_ 0.15. + +_Habitat._--Fossil in Barbados. + + +11. _Theoconus ariadnes_, n. sp. + +Shell conical, nearly bell-shaped, smooth. Length of the three joints = +1 : 2 : 3, breadth = 1 : 3 : 5. Cephalis subspherical, with a conical spine +of about the same length. Thorax hemispherical, thin-walled. Abdomen +conical, slightly constricted at the wide open mouth. Pores regular, +circular, twice as large in the thick-walled abdomen as in the thin-walled +thorax. + +_Dimensions._--Length of the three joints, _a_ 0.018 to 0.022, _b_ 0.03 to +0.035, _c_ 0.06 to 0.07; breadth, _a_ 0.015 to 0.02, _b_ 0.04 to 0.06, _c_ +0.07 to 0.09. + +_Habitat._--Cosmopolitan; Atlantic, Indian, and Pacific Oceans, common, +surface. + + +12. _Theoconus dionysius_, Haeckel. + + _Thyrsocyrtis dionysia_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 84, Taf. xii. fig. 5. + + _Thyrsocyrtis jacchia_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 84, Taf. xii. fig. 7. + +Shell bell-shaped, smooth. Length of the three joints = 1 : 3 : 5, breadth += 1 : 4 : 5. Cephalis subspherical, with a conical, irregularly denticulate +horn of twice or thrice the length. Thorax {1403}inflated, nearly +spherical, truncate at both poles, separated by a deep stricture from the +cephalis, as well as from the conical abdomen, which is dilated gradually +towards the wide mouth. Pores in the thorax subregular, circular, in the +abdomen twice to four times larger, and irregular. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.1; +breadth, _a_ 0.02, _b_ 0.08, _c_ 0.1. + +_Habitat._--Fossil in Barbados. + + +13. _Theoconus laterna_, n. sp. + +Shell conical, smooth. Length of the three joints = 1 : 2 : 4, breadth = +1 : 2 : 4. Cephalis small, ovate, with a strong, pyramidal, vertical horn +three times the length. Thorax hemispherical, with subregular, circular, +hexagonally-framed pores. Abdomen truncate, conical, with only fifteen to +twenty very large, irregular, polygonal pores, which are separated by very +thick bars of the same breadth as the horn. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.06, _c_ 0.12; +breadth, _a_ 0.03, _b_ 0.07, _c_ 0.12. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +14. _Theoconus ficus_, Haeckel. + + _Eucyrtidium ficus_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 70, Taf. xi. fig. 19. + + _Theocorys ficus_, Haeckel, 1881, Prodromus, p. 434. + +Shell conical, pear-shaped, smooth. Length of the three joints = +1 : 5 : 20, breadth = 2 : 10 : 25. Cephalis very small, ovate, with a +conical, straight horn three times the length. Thorax quite conical, with +solid wall, without pores. Abdomen very large, nearly spherical, truncate +at both poles, little constricted at the very wide mouth; its pores +subregular, circular, about three times as broad as the bars. (This species +is intermediate between the genera _Theoconus_ and _Theocorys_.) + +_Dimensions._--Length of the three joints, _a_ 0.01, _b_ 0.05, _c_ 0.2; +breadth, _a_ 0.02, _b_ 0.1, _c_ 0.25. + +_Habitat._--Fossil in Barbados. + + + +Genus 614. _Lophoconus_,[231] n. gen. + +_Definition._--#Theocorida# (vel Tricyrtida eradiata aperta) with conical +abdomen gradually dilated towards the wide open mouth. Cephalis with two or +more horns or a corona of horns. + +The genus _Lophoconus_ has the same conical shell with truncate mouth as +_Theoconus_, and differs from it only in the armature of the cephalis, +bearing either two large divergent horns (usually a larger occipital and a +smaller frontal horns), or a bunch or corona of numerous divergent horns. + + +{1404}1. _Lophoconus antilope_, Haeckel. + + _Eucyrtidium antilope_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 291, Taf. ix. fig. 18. + +Shell conical, smooth, with two slight strictures. Length of the three +joints = 1 : 3 : 8, breadth = 2 : 4 : 8. Cephalis hemispherical, with two +divergent, pyramidal horns of twice the length. Thorax campanulate. Abdomen +gradually dilated towards the wide open mouth. Pores very small and +numerous, regular, hexagonal. + +_Dimensions._--Length of the three joints, _a_ 0.015, _b_ 0.05, _c_ 0.12; +breadth, _a_ 0.025, _b_ 0.07, _c_ 0.12. + +_Habitat._--Indian Ocean; between Aden and Socotra (Haeckel); Zanzibar +(Pullen). + + +2. _Lophoconus hexagonalis_, n. sp. + +Shell campanulate, conical, spiny, with two sharp strictures. Length of the +three joints = 1 : 2 : 4, breadth = 1 : 3 : 6. Cephalis hemispherical, with +numerous conical spines of different sizes, the largest of twice the +length. Thorax campanulate, with smaller spines. Abdomen inflated, dilated +towards the wide mouth. Pores large, three or four times as broad as the +bars, subregular, hexagonal. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.05, _c_ 0.09; +breadth, _a_ 0.03, _b_ 0.07, _c_ 0.12. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +3. _Lophoconus cornutella_, n. sp. + +Shell slender, conical, smooth, without external strictures, but with two +internal, annular septa. Length of the three joints = 1 : 2 : 6, breadth = +1 : 2 : 4. Cephalis ovate, with two stout, divergent, conical horns of +three times the length. Thorax and abdomen together conical, gradually +dilated towards the wide truncate mouth. Pores regular, circular, +quincuncial. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.06, _c_ 0.12; +breadth, _a_ 0.02, _b_ 0.04, _c_ 0.08. + +_Habitat._--North Atlantic, Station 353, depth 2965 fathoms. + + +4. _Lophoconus apiculatus_, Haeckel. + + _Eucyrtidium apiculatum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 70, Taf. x. fig. 10. + +Shell campanulate, conical, thorny, with two distinct strictures. Length of +the three joints = 1 : 2 : 2, breadth = 1 : 3 : 4. Cephalis subspherical, +with a bunch of eight to twelve divergent, conical horns, the largest of +which are longer than the cephalis. The regular, circular pores are in the +campanulate thorax scarcely half as broad as in the truncate, gradually +dilated abdomen. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.04; +breadth, _a_ 0.025, _b_ 0.06, _c_ 0.08. + +_Habitat._--Fossil in Barbados. + + +{1405}5. _Lophoconus cervus_, Haeckel + + ? _Eucyrtidium cervus_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 291, Taf. ix. fig. 21. + +Shell conical, smooth, without external stricture, but with two internal +annular septa. Length of the three joints = 1 : 2 : 4, breadth = 1 : 3 : 6. +Cephalis campanulate, with two to six divergent, partly ramified horns. +Pores in the thorax regular, circular, in the abdomen three to four times +as large, regular, hexagonal. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.08; +breadth, _a_ 0.02, _b_ 0.06, _c_ 0.12. + +_Habitat._--Indian Ocean, Cocos Islands (Rabbe), surface (? Zanzibar, 2200 +fathoms, Pullen). + + +6. _Lophoconus rhinoceros_, n. sp. (Pl. 69, fig. 2). + +Shell campanulate, conical, rough, with two sharp strictures. Length of the +three joints = 1 : 2 : 3, breadth = 1 : 3 : 4. Cephalis subspherical, with +numerous very small pores, and two stout, divergent, pyramidal horns, the +major of which is longer, the minor shorter, than the cephalis. Thorax +campanulate, with small, regular, circular pores. Abdomen inflated, with +thickened margin at the wide open mouth, and with irregular, roundish +pores, twice to four times as broad as those of the thorax. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.05, _c_ 0.09; +breadth, _a_ 0.04, _b_ 0.09, _c_ 0.12. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + + +Genus 615. _Theocyrtis_,[232] n. gen. + +_Definition._--#Theocorida# (vel Tricyrtida eradiata aperta) with +cylindrical abdomen, and wide open truncate mouth. Cephalis with a single +horn. + +The genus _Theocyrtis_ and the three following closely allied genera differ +from the other Theocorida in the cylindrical form of the slender abdomen, +which is of equal breadth nearly throughout its whole length. The terminal +mouth is wide open, usually truncate, and of the same breadth; sometimes +slightly constricted. The cephalis of Theocyrtis bears a single horn. + + + +Subgenus 1. _Theocorypha_, Haeckel. + +_Definition._--Pores of the thorax and abdomen of nearly equal size and +similar form. + + +1. _Theocyrtis trachelius_, Haeckel. + + _Eucyrtidium trachelius_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 293, Taf. vii. fig. 8. + +Shell thin-walled and very fragile, smooth. Length of the three joints = +2 : 8 : 7, breadth = 2 : 9 : 8. Cephalis subspherical, with a straight, +conical horn of the same length, separated by a {1406}slender neck from the +inflated, subspherical thorax. Abdomen cylindrical, with a wide open, +truncate mouth. Pores subregular, hexagonal, of equal size, four to six +times as broad as the thin, thread-like bars. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.08, _c_ 0.07; +breadth, _a_ 0.02, _b_ 0.09, _c_ 0.08. + +_Habitat._--Tropical Pacific, many Stations (200, 224, 271, &c.), surface, +and in various depths. + + +2. _Theocyrtis barbadensis_, Haeckel. + + _Eucyrtidium barbadense_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 70, Taf. ix. fig. 7. + +Shell thin-walled, smooth. Length of the three joints = 2 : 4 : 5, breadth, +2 : 5 : 4. Cephalis ovate or conical, with a strong, conical horn, without +external stricture, dilated into the campanulate thorax. Abdomen +cylindrical, with a wide open, truncate mouth. Pores subregular, circular, +quincuncially disposed, of about the same breadth as the bars. + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.08, _c_ 0.1; +breadth, _a_ 0.04, _b_ 0.1, _c_ 0.08. + +_Habitat._--Fossil in the Tertiary rocks of Barbados. + + +3. _Theocyrtis cylindrica_, Haeckel. + + _Eucyrtidium cylindricum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 70, Taf. x. fig. 1. + +Shell elongate, cylindrical, straight, smooth. Length of the three joints = +1 : 2 : 6, breadth = 1 : 3 : 3. Cephalis hemispherical, with a thick, +pyramidal horn of the same length (the edges of the horn giving to it the +appearance of being composed of two converging spines). Thorax truncated, +conical. Abdomen perfectly cylindrical, much elongated. Pores subregular, +circular, twice as broad as the bars, quincuncially disposed. Mouth wide +open, truncate. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.12; +breadth, _a_ 0.03, _b_ 0.06, _c_ 0.06. + +_Habitat._--Tropical Pacific, Station 266, depth 2750 fathoms; fossil in +Barbados. + + +4. _Theocyrtis elegans_, Haeckel. + + _Eucyrtidium elegans_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 70, Taf. xi. fig. 12. + + ? _Eucyrtidium pusillum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 72, Taf. xi. fig. 6 + +Shell slender, cylindrical, straight, smooth. Length of the three joints = +1 : 2 : 7, breadth = 1 : 3 : 3. Cephalis subconical, with a small conical +horn. Thorax campanulate, conical. Abdomen cylindrical, very slender. Pores +subregular, circular, small, disposed in transverse rows, three in the +thorax, six to eight in the abdomen. Mouth wide open, truncate. + +_Dimensions._--Length of the three joints, _a_ 0.01, _b_ 0.02, _c_ 0.07; +breadth, _a_ 0.015, _b_ 0.03, _c_ 0.03. + +_Habitat._--Fossil in Barbados and Sicily. + + +{1407}5. _Theocyrtis paupera_, Haeckel. + + _Eucyrtidium pauperum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 72, Taf. xi. fig. 13. + +Shell slender, cylindrical, smooth. Length of the three joints = 1 : 2 : 6, +breadth = 1 : 3 : 3. Cephalis hemispherical, with a stout conical horn of +twice the length. Thorax truncate, conical. Abdomen cylindrical. Pores very +small, regular, circular, disposed in transverse rows, one or two in the +thorax, three to five in the abdomen. (Distance between the rows twice as +great as in the preceding nearly related species.) Mouth wide open, +truncate. + +_Dimensions._--Length of the three joints, _a_ 0.01, _b_ 0.02, _c_ 0.06; +breadth, _a_ 0.015, _b_ 0.03, _c_ 0.03. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms; also +fossil in Barbados and Sicily. + + +6. _Theocyrtis microtheca_, Haeckel. + + _Eucyrtidium microtheca_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 72, Taf. xi. fig. 10. + + _Eucyrtidium hillaby_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 72, Taf. xi. fig. 8. + +Shell cylindrical, a little rough. Length of the three joints = 1 : 3 : 4, +breadth = 1 : 3 : 3. Cephalis subspherical, with a small conical horn. +Thorax hemispherical or campanulate. Abdomen cylindrical, with wide open +truncate mouth. Pores subregular, circular, quincuncially disposed, of +medium size, rudimentary or wanting in the cephalis. + +_Dimensions._--Length of the three joints, _a_ 0.015 to 0.02, _b_ 0.03 to +0.05, _c_ 0.05 to 0.08; breadth, _a_ 0.02 to 0.025, _b_ 0.05 to 0.06, _c_ +0.05 to 0.06. + +_Habitat._--Central Pacific, Stations 263 to 274, depth 2350 to 2925 +fathoms; also fossil in Barbados. + + + +Subgenus 2. _Theocorusca_, Haeckel. + +_Definition._--Pores of the thorax and the abdomen of different sizes or +forms. + + +7. _Theocyrtis macroceros_, n. sp. (Pl. 69, fig. 13). + +Shell almost cylindrical, smooth. Length of the three joints = 1 : 2 : 5, +breadth = 2 : 3 : 4. Cephalis hemispherical, with a very large cylindrical +horn, once or twice as long as the shell. Thorax truncate, hemispherical. +Abdomen cylindrical, only slightly contracted towards both ends. Two girdle +strictures deep. Pores small, subregular, circular, more irregular and +twice to three times as large in the abdomen as in the thorax, disposed in +transverse rows, five to six in the thorax, eight to ten in the abdomen. + +_Dimensions._--Length of the three joints, _a_ 0.02 to 0.03, _b_ 0.04 to +0.05, _c_ 0.1 to 0.12; breadth, _a_, 0.04, _b_ 0.07, _c_ 0.08. + +_Habitat._--South Atlantic, Station 335, depth 1425 fathoms; also fossil in +Barbados. + + +{1408}8. _Theocyrtis ptychodes_, n. sp. (Pl. 69, fig. 8). + +Shell almost cylindrical, smooth. Length of the three joints = 1 : 3 : 3, +breadth = 2 : 4 : 4. Cephalis hemispherical, with a large, conical, curved +horn of twice the length. Thorax very large, inflated, campanulate, +thick-walled. Abdomen cylindrical, with a thin folded wall (like a +petticoat), the thickness of which decreases gradually towards the wide +truncate mouth. Pores subregular, circular, and quincuncially disposed in +the two first joints, irregular and larger in the abdomen, forming +longitudinal series between the folds. + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.1, _c_ 0.11; +breadth, _a_ 0.05, _b_ 0.12, _c_ 0.12. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +9. _Theocyrtis aspera_, Haeckel. + + _Eucyrtidium asperum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 70, Taf. viii. fig. 15. + +Shell almost cylindrical, with rough or thorny surface. Length of the three +joints = 1 : 3 : 5, breadth = 1 : 5 : 5. Cephalis subspherical, small, with +a short conical horn. Thorax hemispherical, inflated. Abdomen cylindrical, +with wide truncate mouth. Pores in the thorax subregular, circular, +quincuncially disposed, in the abdomen irregular roundish, two to four +times as large. + +_Dimensions._--Length of the three joints, _a_ 0.015 to 0.02, _b_ 0.06 to +0.07, _c_ 0.08 to 0.1; breadth, _a_ 0.02, _b_ 0.1, _c_ 0.1. + +_Habitat._--Tropical Atlantic, Station 338, depth 1990 fathoms; fossil in +Barbados. + + +10. _Theocyrtis proserpinae_, n. sp. + +Shell almost cylindrical, smooth. Length of the three joints = 3 : 6 : 9, +breadth = 2 : 8 : 7. Cephalis subspherical, with a stout conical horn. +Thorax campanulate. Abdomen cylindrical. Pores regular, circular, +quincuncially disposed, double-edged in the thorax, and three to four times +as large as in the cephalis and the abdomen. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.06, _c_ 0.09; +breadth, _a_ 0.02, _b_ 0.08, _c_ 0.07. + +_Habitat._--North Pacific, Stations 244 to 253, depth 2050 to 3125 fathoms. + + +11. _Theocyrtis oenophila_, Haeckel. + + _Thyrsocyrtis oenophila_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 84, Taf. xii. fig. 8. + +Shell in the apical half conical, in the lower cylindrical. Length of the +three joints = 2 : 5 : 6, breadth = 3 : 8 : 7. Cephalis subspherical, with +a large prismatic horn, which is bulbous at the base, and armed with three +teeth at the distal apex. Thorax conical, constricted at the base, with +subregular, circular, quincuncial pores. Abdomen cylindrical, with a +coronal of nine large {1409}roundish pores beyond the lumbar stricture, and +two to four succeeding transverse rows of irregular, roundish, smaller +pores. Mouth widely open, truncated. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.05, _c_ 0.06; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.07. + +_Habitat._--Fossil in Barbados. + + + +Genus 616. _Theosyringium_, Haeckel,[233] 1881, Prodromus, p. 434. + +_Definition._--#Theocorida# (vel Tricyrtida eradiata aperta) with +cylindrical abdomen, which is much narrower than the inflated thorax, and +forms a slender, narrow tube, with truncated mouth. Cephalis with a single +horn. + +The genus _Theosyringium_ differs from the closely allied _Theocyrtis_, its +ancestral form, in the wide inflated thorax, which is much broader than the +narrow tubular abdomen. The mouth of the latter is small and truncate. + + +1. _Theosyringium tibia_, n. sp. (Pl. 68, fig. 4). + +Shell rough, very slender, with two distinct strictures. Length of the +three joints = 1 : 3 : 4, breadth = 1 : 2 : 1. Cephalis ovate, with a +conical horn of the same length. Thorax ellipsoidal. Abdomen cylindrical, +as long as the two former joints together. Pores subregular, circular. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.09, _c_ 0.12; +breadth, _a_ 0.03, _b_ 0.06, _c_ 0.02. + +_Habitat._--Central Pacific, Station 263, depth 2650 fathoms. + + +2. _Theosyringium pipetta_, n. sp. (Pl. 68, fig. 5). + +Shell rough, inflated, with two sharp strictures. Length of the three +joints = 2 : 7 : 9, breadth = 2 : 7 : 2. Cephalis conical, with a slender +horn of half the length. Thorax subglobose. Abdomen cylindrical, as long as +the two former joints together. Pores subregular, circular. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.07, _c_ 0.09; +breadth, _a_ 0.02, _b_ 0.07, _c_ 0.02. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +3. _Theosyringium siphonium_, n. sp. + +Shell rough, inflated, with two deep strictures. Length of the three joints += 1 : 3 : 3, breadth = 1 : 2 : 1. Cephalis subspherical, with a stout +pyramidal horn of twice the length. Thorax broad ovate. Abdomen slender, +inversely conical, as long as the thorax, and one-third as broad as the +base. Pores subregular, circular, hexagonally framed, (Similar to +_Eusyringium conosiphon_, Pl. 78, fig. 10, but only with two strictures and +three joints.) + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.1, _c_ 0.1; +breadth, _a_ 0.03, _b_ 0.07, _c_ 0.025. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +{1410}4. _Theosyringium tubulus_, Haeckel. + + _Eucyrtidium tubulus_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 72, Taf. xi. fig. 6. + +Shell smooth, slenderly spindle-shaped, with two slight strictures. Length +of the three joints = 2 : 10 : 8, breadth = 3 : 6 : 3. Cephalis +hemispherical, hyaline, with a stout, pyramidal horn of the same length. +Thorax spindle-shaped. Abdomen inversely conical, half as long as the +thorax prolonged into a slender, cylindrical tube. Pores subregular, +circular. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.1, _c_ 0.08; +breadth, _a_ 0.03, _b_ 0.06, _c_ 0.03. + +_Habitat._--Fossil in Barbados. + + + +Genus 617. _Lophocyrtis_,[234] n. gen. + +_Definition._--#Theocorida# (vel Tricyrtida eradiata aperta) with +cylindrical abdomen, and wide open truncate mouth. Cephalis with two +horns, or a bunch of horns. + +The genus _Lophocyrtis_ differs from its ancestral form _Theocyrtis_ only +in the armature of the cephalis, bearing instead of a single horn either +two divergent horns, or a bunch, or coronal of numerous spines. The slender +abdomen is in both genera cylindrical, with wide open mouth. + + +1. _Lophocyrtis holothuria_, n. sp. + +Shell smooth, slender, with two distinct strictures. Length of the three +joints = 1 : 2 : 4, breadth = 2 : 4 : 3. Cephalis hemispherical, with a +bunch of five divergent, conical horns, the middle of which is larger and +vertical, nearly as long as the thorax. Thorax campanulate, half as long as +the cylindrical abdomen. Mouth truncate. Pores regular, circular, +quincuncial. (Similar to _Theocyrtis cylindrica_, but with different +cephalis and thorax.) + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.05, _c_ 0.1; +breadth, _a_ 0.04, _b_ 0.07, _c_ 0.06. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +2. _Lophocyrtis stephanophora_, Haeckel. + + _Eucyrtidium stephanophorum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. + Wiss. Berlin p. 72, Taf. viii. fig. 14. + +Shell smooth, slender, with deep collar and indistinct lumbar stricture. +Length of the three joints = 1 : 2 : 4, breadth = 1 : 3 : 3. Cephalis +subspherical, with very small circular pores, and a corona of three to nine +short conical spines. Thorax campanulate, with regular, circular pores, +which are half or one-third as broad as those of the cylindrical abdomen. + +_Dimensions._--Length of the three joints, _a_ 0.025, _b_ 0.05, _c_ 0.09; +breadth, _a_ 0.025, _b_ 0.06, _c_ 0.06. + +_Habitat._--Fossil in Barbados. + + +{1411}3. _Lophocyrtis synapta_, n. sp. Pl. 68, fig. 15. + +Shell spiny, with two sharp strictures. Length of the three joints = +5 : 10 : 6, breadth = 4 : 9 : 7. Cephalis large, ovate, with numerous +(twenty to thirty or more) conical, radially divergent spines of different +sizes, the largest about as long as the cephalis. Thorax subconical, with +numerous short, conical, divergent spines, which are directed downwards. +Abdomen smooth, cylindrical. The irregular, polygonal pores are separated +by thin bars, and in the thorax are twice to four times as broad as in the +first and last joints. + +_Dimensions._--Length of the three joints, _a_ 0.05, _b_ 0.1, _c_ 0.06; +breadth, _a_ 0.04, _b_ 0.09, _c_ 0.07. + +_Habitat._--Indian Ocean, Maldive Islands (Haeckel), surface. + + +4. _Lophocyrtis coronata_, Haeckel. + + _Eucyrtidium coronatum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 70, Taf. x. fig. 9. + +Shell smooth, cylindrical, with two deep strictures. Length of the three +joints = 4 : 3 : 4, breadth = 4 : 5 : 4. Cephalis subspherical, large, of +about the same size and form as the thorax, with a coronal of four to eight +short, conical spines on the apex. Pores in the two first joints irregular, +roundish, twice to four times as broad as the small, circular pores of the +cylindrical abdomen, which are disposed in four to eight transverse rows. + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.03, _c_ 0.04; +breadth, _a_ 0.04, _b_ 0.05, _c_ 0.04. + +_Habitat._--Central Pacific, Station 273, depth 2350 fathoms; fossil in +Barbados. + + +5. _Lophocyrtis biaurita_, Haeckel. + + _Eucyrtidium biauritum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 70, Taf. x. fig. 8. + + _Eucyrtidium biauritum_, Buetschli, 1882, Zeitschr. f. wiss. Zool., p. + 540, Taf. xxxiii. fig. 38, _a_-_f_. + +Shell smooth, with two distinct strictures. Length of the three joints = +1 : 6 : 3, breadth = 2 : 5 : 4. Cephalis small, hemispherical, hyaline, +with two large, divergent, curved horns of three times the length. Thorax +ovate, with few small, widely scattered pores. Abdomen cylindrical, without +pores. + +_Dimensions._--Length of the three joints, _a_ 0.015, _b_ 0.06, _c_ 0.03; +breadth, _a_ 0.02, _b_ 0.05, _c_ 0.04. + +_Habitat._--Fossil in Barbados. + + + +Genus 618. _Tricolocampe_,[235] Haeckel, 1881, Prodromus, p. 434. + +_Definition_.--#Theocorida# (vel Tricyrtida eradiata aperta), with +cylindrical abdomen, and wide open truncate mouth. Cephalis without horn. + +The genus _Tricolocampe_ differs from its ancestral genus, _Theocyrtis_, in +the loss of the cephalic horn; it has the same cylindrical form of the +slender abdomen, and a wide {1412}open terminal mouth of the same breadth. +The whole shell is more or less cylindrical, (sometimes conical in the +upper part), with two distinct external strictures, or internal annular +septa. + + + +Subgenus 1. _Tricolocampium_, Haeckel. + +_Definition._--Pores of the thorax and of the abdomen of nearly equal size +and similar form. + + +1. _Tricolocampe cylindrica_, n. sp. (Pl. 66, fig. 21). + +Shell nearly cylindrical, smooth. Length of the three joints = 2 : 3 : 15, +breadth = 3 : 4 : 5. Cephalis hemispherical, with numerous very small +pores. Thorax and abdomen cylindrical, of about equal breadth, with equal, +circular pores, disposed regularly in transverse rows, three to four rows +in the thorax, ten to twelve in the abdomen. Mouth wide open, not +constricted. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.03, _c_ 0.15; +breadth, _a_ 0.03, _b_ 0.04, _c_ 0.05. + +_Habitat._--Central Pacific, Stations 265 to 274, depth 2350 to 2925 +fathoms. + + +2. _Tricolocampe pupa_, Haeckel. + + _Eucyrtidium pupa_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 293, Taf. vii. fig. 16. + +Shell nearly cylindrical, smooth. Length of the three joints = 2 : 2 : 8, +breadth = 2 : 3 : 3. Cephalis subspherical, with four larger pores. Thorax +and abdomen cylindrical, of about equal breadth, with equal, very small +pores, disposed regularly in transverse rows, two rows in the thorax, eight +to ten in the abdomen. Mouth wide open, a little constricted. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.02, _c_ 0.08; +breadth, _a_ 0.02, _b_ 0.03, _c_ 0.03. + +_Habitat._--Tropical Pacific (Philippine Sea), Station 206, depth 2100 +fathoms. + + +3. _Tricolocampe polyzona_, n. sp. (Pl. 66, fig. 19). + +Shell nearly cylindrical, thick-walled. Length of the three joints = +4 : 4 : 12, breadth = 8 : 9 : 9. Cephalis obtuse, conical. Thorax +barrel-shaped. Abdomen in the middle part a little constricted. Pores very +numerous, subregular, disposed regularly in transverse rows, six to eight +in the cephalis, eight to ten in the thorax, twelve to fifteen in the +abdomen. Mouth rather constricted, only half as broad as the abdomen. + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.04, _c_ 0.12; +breadth, _a_ 0.08, _b_ 0.09, _c_ 0.09. + +_Habitat._--Central Pacific, Stations 266 to 272, depth 2425 to 2925 +fathoms; also fossil in the Nicobars and in Barbados. + + +{1413}4. _Tricolocampe stenozona_, n. sp. (Pl. 66, fig. 20). + +Shell nearly cylindrical, thin-walled. Length of the three joints = +5 : 4 : 9, breadth = 6 : 8 : 9. Form of the three joints and disposition of +their pores nearly equal to the preceding species; but the proportion of +the joints is different, the shell more delicate, and the mouth more widely +open, and nearly as broad as the abdomen. + +_Dimensions._--Length of the three joints, _a_ 0.05, _b_ 0.04, _c_ 0.09; +breadth, _a_ 0.06, _b_ 0.08, _c_ 0.09. + +_Habitat._--North Pacific, Station 256, depth 2950 fathoms. + + +5. _Tricolocampe amphizona_, n. sp. (Pl. 66, fig. 17). + +Shell mitre-shaped, very thick-walled. Length of the three joints = +2 : 1 : 1, breadth nearly uniform. Cephalis obtuse, conical, as long as the +two other cylindrical joints together (probably composed of several united +joints). Pores subregular, disposed in transverse rows, six to eight in the +cephalis, two in the thorax, and two in the abdomen. Mouth widely open. + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.02, _c_ 0.02; +breadth, _a_ 0.04, _b_ 0.05, _c_ 0.05. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms. + + +6. _Tricolocampe panthera_, Haeckel. + + _Eucyrtidium panthera_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 72, Taf. xi. fig. 18. + +Shell mitre-shaped or nearly cylindrical, thick-walled. Length of the three +joints = 1 : 2 : 3, breadth = 1 : 2 : 2. Cephalis subspherical. Thorax +campanulate. Abdomen cylindrical. Pores in all three joints irregular, +roundish, of different sizes, irregularly disposed. Mouth widely open, +truncated, not constricted. + +_Dimensions._--Length of the three joints, _a_ 0.015 to 0.02, _b_ 0.04 to +0.05, _c_ 0.06 to 0.08; breadth about _a_ 0.02, _b_ and _c_ 0.05. + +_Habitat._--Cosmopolitan; Atlantic, Pacific; also fossil in Barbados. + + + +Subgenus 2. _Tricolocamptra_, Haeckel. + +_Definition._--Pores of the thorax and the abdomen of different sizes or +forms. + + +7. _Tricolocampe urnula_, n. sp. (Pl. 66, fig. 22). + +Shell cylindrical, with obtuse conical apex, smooth. Length of the three +joints = 2 : 3 : 10, breadth = 2 : 3 : 6. Cephalis subspherical. Thorax +barrel-shaped. Abdomen cylindrical with slightly constricted wide mouth. +Pores irregular, roundish, three to four times as broad in the abdomen as +in the thorax, irregularly disposed. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.03, _c_ 0.1; +breadth, _a_ 0.025, _b_ 0.035, _c_ 0.06. + +_Habitat._--Central Pacific, Stations 270 to 274, depth 2350 to 2925 +fathoms. + + +{1414}8. _Tricolocampe doliolum_, n. sp. + +Shell cylindrical, with hemispherical apex, rough. Length of the three +joints = 1 : 3 : 5, breadth = 1 : 2 : 3. Cephalis spherical. Thorax and +abdomen cylindrical, of nearly equal breadth. Mouth widely open, not +constricted. Pores irregular, roundish, in the abdomen three to four times +as large as in the thorax, disposed in oblique rows. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.09, _c_ 0.16; +breadth, _a_ 0.03, _b_ 0.05, _c_ 0.09. + +_Habitat._--Fossil in Barbados. + + +9. _Tricolocampe cingulata_, n. sp. + +Shell subcylindrical, with obtuse conical apex, thick-walled. Length of the +three joints = 2 : 3 : 11, breadth = 3 : 7 : 8. Cephalis hemispherical, not +separated externally from the short conical thorax, but with internal +collar septum. Abdomen cylindrical, with wide open, non-constricted mouth. +Pores in the thorax narrow, obliquely ascending, in the abdomen twice as +large, circular, arranged in ten to twelve regular transverse rows, +separated by slight strictures. Lumbar septum nearly complete. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.03, _c_ 0.1 to +0.12; breadth, _a_ 0.03, _b_ 0.07, _c_ 0.08. + +_Habitat._--Fossil in Barbados, and in Tertiary rocks of Sicily; living in +the depths of the Atlantic and Central Pacific, Station 348, depth 2450 +fathoms; Station 268, depth 2900 fathoms. + + +10. _Tricolocampe arcta_, Haeckel. + + ? _Eucyrtidium arctum_, Ehrenberg, 1858, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, p. 33. + + ? _Lithocampe arcta_, Haeckel, 1862, Monogr. d. Radiol., p. 317. + +Shell subcylindrical, with obtuse conical apex. Length of the three joints += 1 : 2 : 4, breadth = 1 : 2 : 2. Cephalis subspherical. Thorax +campanulate, separated by a deep collar, but a slight lumbar stricture. +Abdomen cylindrical, with wide truncate mouth. Pores in the thorax narrow, +obliquely ascending, in the abdomen half as large, very small, and densely +disposed in six to eight regular transverse rows. + +_Dimensions._--Length of the three joints, _a_ 0.022, _b_ 0.045, _c_ 0.09; +breadth, _a_ 0.026, _b_ 0.05, _c_ 0.05. + +_Habitat._--Central Pacific, Station 266 to 274, depth 2350 to 2925 +fathoms. + + + +Genus 619. _Theocorys_,[236] Haeckel, 1881, Prodromus, p. 434. + +_Definition._--#Theocorida# (vel Tricyrtida eradiata aperta) with ovate +abdomen, broader than the constricted mouth. Cephalis with a single horn. + +The genus _Theocorys_ and the two following closely allied genera, united +formerly with _Eucyrtidium_, differ from the preceding Theocorida in the +constriction of the {1415}peristome, so that the inflated abdomen is +broader than the terminal mouth. They represent, therefore, the transition +to the Theocapsida, with closed mouth. The abdomen is commonly more or less +ovate or barrel-shaped, sometimes inversely conical. The cephalis of +_Theocorys_ bears a single apical horn. + + + +Subgenus 1. _Theocoronium_, Haeckel. + +_Definition._--Pores of the thorax and of the abdomen of nearly equal size +and similar form. + + +1. _Theocorys turgidula_, Haeckel. + + _Eucyrtidium turgidulum_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 293, Taf. vii. fig. 13. + +Shell slender, ovate, with two deep strictures, very fragile and +thin-walled. Length of the three joints = 2 : 5 : 7, breadth = 2 : 6 : 6. +Cephalis subspherical, with a pyramidal horn of the same length. Thorax +nearly spherical. Abdomen ovate, twice as broad as the constricted mouth. +Pores very numerous, regular hexagonal, three to four times as broad as the +bars. + +_Dimensions._--Length of the three joints, _a_ 0.015, _b_ 0.05, _c_ 0.07; +breadth, _a_ 0.02, _b_ 0.06, _c_ 0.06. + +_Habitat._--Tropical Pacific (Philippine Sea), Stations 206 and 224, +surface. + + +2. _Theocorys veneris_, n. sp. (Pl. 69, fig. 5). + +Shell inversely ovate, with two deep strictures, smooth. Length of the +three joints = 2 : 5 : 6, breadth = 3 : 7 : 6. Cephalis hemispherical, with +a slender conical horn of twice the length. Thorax nearly spherical. +Abdomen ovate, twice as broad as the constricted mouth. Pores regular, +circular, twice as broad as the bars, quincuncially disposed. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.05, _c_ 0.06; +breadth, _a_ 0.03, _b_ 0.07, _c_ 0.06. + +_Habitat._--Cosmopolitan; Atlantic, Indian, Pacific; many Stations, +surface. + + +3. _Theocorys cretica_, Haeckel. + + _Eucyrtidium creticum_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 291, Taf. xi. fig. 23. + +Shell ovate, thin-walled, smooth, with two deep strictures. Length of the +three joints = 2 : 4 : 4, breadth = 3 : 6 : 6. Cephalis hemispherical, with +a conical horn of the same length. Thorax and abdomen nearly hemispherical, +inflated, united by the opposite bases of the hemispheres. Constricted +mouth only one-third as broad as the abdomen. Pores very small and +numerous, regular, circular, of the same breadth as the bars, quincuncially +disposed. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.04; +breadth, _a_ 0.03, _b_ 0.06, _c_ 0.06. + +_Habitat._--Mediterranean, Crete, Corfu, surface. + + +{1416}4. _Theocorys ovata_, n. sp. (Pl. 69, fig. 16). + +Shell quite ovate, thick-walled, smooth, without external strictures. +Length of the three joints = 2 : 2 : 9. breadth = 3 : 5 : 7. Cephalis +conical, with a thick conical horn of the same length. Thorax and abdomen +gradually dilated towards the base, and then hemispherical, constricted. +Mouth scarcely one-third as broad as the abdomen, prolonged into a short +tube. Pores regular, circular, disposed in transverse rows, two to three in +the cephalis, two to three in the thorax, eight to ten in the abdomen. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.02, _c_ 0.09; +breadth, _a_ 0.03, _b_ 0.05, _c_ 0.07. + +_Habitat._--Central Pacific, Stations 263 to 268, depth 2650 to 3000 +fathoms. + + +5. _Theocorys plutonis_, n. sp. (Pl. 69, fig. 1). + +Shell ovate, thick-walled, smooth, with two slight strictures. Length of +the three joints = 2 : 5 : 4, breadth = 4 : 7 : 6. Cephalis hemispherical, +with a conical, oblique horn of the same length. Thorax and abdomen only +slightly inflated, gradually decreasing towards the wide, little +constricted mouth. Pores subregular, circular, much larger in the abdomen +and the lower half of the thorax than in the upper half and the cephalis. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.05, _c_ 0.04; +breadth, _a_ 0.04, _b_ 0.07, _c_ 0.06. + +_Habitat._--South Pacific, Station 295, depth 1500 fathoms. + + +6. _Theocorys scolopax_, Haeckel. + + _Eucyrtidium scolopax_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 72, Taf. ix. fig. 5. + +Shell slender, inversely ovate, smooth. Length of the three joints = +1 : 3 : 3, breadth = 1 : 4 : 4. Cephalis subspherical, with a long, +slightly curved horn, half as long as the whole shell. Thorax campanulate. +Abdomen inversely ovate, twice as broad as the constricted mouth +(incomplete in Ehrenberg's figure). + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.06; +breadth, _a_ 0.02, _b_ 0.08, _c_ 0.08. + +_Habitat._--Fossil in Barbados. + + + +Subgenus 2. _Theocorythium_, Haeckel. + +_Definition._--Pores of the thorax and of the abdomen of different sizes or +dissimilar forms. + + +7. _Theocorys dianae_, n. sp. (Pl. 69, fig. 11). + +Shell almost ovate, with two deep strictures. Length of the three joints = +3 : 6 : 8, breadth = 3 : 9 : 8. Cephalis subspherical, with a slender, +pyramidal horn of three times the length. Thorax {1417}conical, constricted +at the base. Abdomen bottle-shaped. Pores in the thorax irregular, +polygonal, in the abdomen subregular, circular, quincuncially disposed. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.06, _c_ 0.08; +breadth, _a_ 0.03, _b_ 0.09, _c_ 0.08. + +_Habitat._--North Pacific, Station 253, surface. + + +8. _Theocorys hyalothorax_, n. sp. + +Shell slender, ovate, with two deep strictures. Length of the three joints += 6 : 9 : 8, breadth = 7 : 12 : 11. Cephalis subspherical, with numerous +densely-placed circular pores, and with a pyramidal, slender horn of the +same length. Thorax hemispherical, hyaline, without any pores. Abdomen +ovate, twice as broad as the constricted mouth, with two to four widely +distant, transverse rows of small, circular pores. + +_Dimensions._--Length of the three joints, _a_ 0.024, _b 0_.036, _c_ 0.032; +breadth, _a_ 0.028, _b 0_.048, _c_ 0.044. + +_Habitat._--Tropical Pacific, Station 225, depth 4475 fathoms. + + +9. _Theocorys bachabunda_, Haeckel. + + _Thyrsocyrtis bachabunda_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 84, Taf. xii. fig. 4. + +Shell inversely ovate, with two distinct strictures. Length of the three +joints = 2 : 5 : 9, breadth = 3 : 9 : 8. Cephalis subspherical, small, with +a large cylindrical horn, which is half as long as the whole shell, and +armed with spines at the conical apex. Thorax conical, inflated, with +small, subregular, circular, quincuncial pores. Abdomen inversely ovate, +with irregular, roundish, pores of larger and smaller sizes mixed, +gradually lessening towards the constricted mouth. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.05, _c_ 0.09; +breadth, _a_ 0.03, _b_ 0.09, _c_ 0.08. + +_Habitat._--Fossil in Barbados. + + +10. _Theocorys attenuata_, Haeckel. + + _Eucyrtidium attenuatum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 70, Taf. xi. fig. 16. + +Shell inversely ovate, with distinct collar, but indistinct lumbar +stricture. Length of the three joints = 2 : 5 : 5, breadth = 2 : 7 : 6. +Cephalis hemispherical, with a short, oblique, conical horn. Thorax +inflated, campanulate, with small, regular, circular, quincuncial pores. +Abdomen inversely conical, with irregular pores of larger and smaller sizes +mixed, gradually lessening towards the truncated mouth. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.05, _c_ 0.05; +breadth, _a_ 0.025, _b_ 0.07, _c_ 0.06. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms; also fossil +in Barbados. + + +11. _Theocorys obliqua_, n. sp. (Pl. 69, fig. 10). + +Shell inversely ovate, with distinct collar, but indistinct lumbar +stricture. Length of the three joints = 3 : 7 : 4, breadth = 4 : 9 : 8. +Cephalis hemispherical, with a stout, pyramidal, oblique {1418}horn of the +same length. Thorax and abdomen together ovate, gradually lessening towards +the constricted mouth, which is only half as broad. Pores irregular, +roundish, in the thorax twice to four times as broad as in the abdomen. +Both joints are separated by an oblique, internal, lumbar septum, which in +some specimens observed was more oblique than in that figured; some +specimens had a very irregular form. + +_Dimensions._--Length of the three joints, _a_ 0.025 to 0.03, _b_ 0.06 to +0.07, _c_ 0.03 to 0.04; breadth, _a_ 0.04, _b_ 0.09, _c_ 0.08. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms; also fossil +in Barbados. + + +12. _Theocorys alauda_, Haeckel. + + _Eucyrtidium alauda_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 72, Taf. ix. fig. 4. + +Shell nearly spindle-shaped, decreasing from the thicker middle towards +both ends. Length of the three joints = 1 : 3 : 8, breadth = 1 : 4 : 5. +Cephalis subspherical, with a strong, conical horn of three times the +length. Thorax campanulate, with numerous regular, circular, quincuncial +pores. Abdomen inversely ovate, slender, twice as broad as the truncated +mouth, with irregular, roundish pores, three to four times as large as +those of the thorax. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.16; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.1. + +_Habitat._--Fossil in Barbados and in Tertiary rocks of Sicily. + + +13. _Theocorys apollinis_, n. sp. (Pl. 69, fig. 3). + +Shell ovate, with two deep strictures. Length of the three joints = +2 : 3 : 5, breadth = 2 : 5 : 7. Cephalis subspherical, with a large, +straight, cylindrical horn, about as long as the whole shell (in the +specimen figured this is broken off). Thorax truncate, conical. Abdomen +subglobose, truncate on both poles, twice as broad as the constricted +mouth. Pores quincuncial, subregular, circular, twice as broad in the +abdomen as in the thorax. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.03, _c_ 0.05; +breadth, _a_ 0.02, _b_ 0.05, _c_ 0.07. + +_Habitat._--South Atlantic, Station 332, surface. + + +14. _Theocorys sphaerophila_, Haeckel. + + _Eucyrtidium sphaerophilum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 72, Taf. viii. fig. 16. + +Shell almost ovate, rough, with two slight strictures. Length of the three +joints = 2 : 7 : 10, breadth = 3 : 8 : 12. Cephalis subspherical, with a +strong, conical horn of the same length. Thorax nearly spherical, with +subregular, circular pores of different sizes. Abdomen ovate, truncate at +both poles, nearly twice as broad as the constricted mouth, with very +large, subregular, hexagonal pores, four to six times as broad as the bars, +in three to four transverse, and ten to twelve longitudinal rows. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.07, _c_ 0.1; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.12. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms; fossil in +Barbados. + + +{1419}15. _Theocorys tuberculata_, n. sp. + +Shell almost ovate, tuberculate, with deep collar, but slight lumbar +stricture. Length of the three joints = 2 : 5 : 12, breadth = 3 : 8 : 11. +Cephalis hemispherical, with a cylindrical horn of twice the length. Thorax +hemispherical, with regular, circular, double-edged, quincuncial pores, +between which conical tubercles occur. Abdomen truncate, ovate, twice as +broad as the constricted mouth, with regular, circular, hexagonally-framed +pores, three to four times as broad as those of the thorax. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.05, _c_ 0.12; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.11. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms; fossil in +Barbados. + + +16. _Theocorys martis_, n. sp. + +Shell slender, ovate, with two deep strictures. Length of the three joints += 3 : 6 : 18, breadth = 4 : 8 : 12. Cephalis small, hemispherical, with a +very large, sword-shaped broad horn, nearly as long as the whole shell. +Thorax hemispherical, honey-comb like, with regular, circular, +hexagonally-framed pores. Abdomen ovate, with irregular, roundish, very +large pores, four to six times as broad as the bars, and as the pores of +the thorax. Constricted mouth half as broad as the abdomen. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.06, _c_ 0.18; +breadth, _a_ 0.04, _b_ 0.08, _c_ 0.12. + +_Habitat._--South Pacific, Station 295, depth 1500 fathoms. + + +17. _Theocorys mercurii_, n. sp. + +Shell ovate, conical, with two slight strictures. Length of the three +joints = 1 : 3 : 7, breadth = 2 : 4 : 7. Cephalis hemispherical, with a +broad pyramidal horn of the same length. Thorax campanulate, with +longitudinal series of small, regular, circular pores, separated by +divergent crests. Abdomen nearly spherical, one and a half times as broad +as the constricted mouth, which is prolonged into a thin, solid, +cylindrical peristome. Pores of the abdomen regular, circular, hexagonally +framed, three to four times as broad as the bars, and as the pores of the +thorax. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.15; +breadth, _a_ 0.04, _b_ 0.09, _c_ 0.15. + +_Habitat._--South Atlantic, Station 338, depth 1990 fathoms. + + +18. _Theocorys minervae_, n. sp. (Pl. 69, fig. 14). + +Shell ovate, conical, with two deep strictures. Length of the three joints += 1 : 3 : 4, breadth = 1 : 4 : 5. Cephalis subspherical, with a large +pyramidal horn as long as the thorax, and with small, circular pores. +Thorax rough, with regular, quincuncial, circular pores, three to four +times as large as those of the cephalis. Abdomen barrel-shaped, with +irregular, roundish pores of very different sizes, six very large pores +immediately beyond the lumbar stricture, and four to five rows {1420}of +pores, which are twice to four times as large as those of the thorax. Mouth +truncated, with thickened margin, two-thirds as broad as the abdomen. + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.12, _c_ 0.16; +breadth, _a_ 0.04, _b_ 0.16, _c_ 0.2. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + + +Genus 620. _Axocorys_,[237] Haeckel, 1881, Prodromus, p. 434. + +_Definition._--#Theocorida# (vel Tricyrtida eradiata aperta), with ovate +abdomen, including an internal vertical axial rod, which bears three +divergent radial spines or verticils of three branches, and is prolonged +into an apical horn. + +The genus _Axocorys_ contains only a single but very remarkable species, +and may, perhaps, represent a peculiar group, which has closer relations to +the #Plectoidea# than to the other Tricyrtida. The pyriform three-jointed +shell has neither lateral nor terminal free appendages, but possesses a +very large apical horn, and an inner prolongation of this, an axial rod, +which bears some triradiate verticils of branched spines. The original +ancestral forms of this remarkable genus are probably _Plagoniscus_ and +_Plectaniscus_ (pp. 912 and 924). + + +1. _Axocorys macroceros_, n. sp. (Pl. 68, figs. 1, 1_a_). + +Shell pear-shaped, with two distinct strictures. Length of the three joints += 2 : 3 : 16, breadth = 3 : 6 : 16. Cephalis hemispherical, with few small +pores. From its apex arises vertically a very long three-sided prismatic +horn with denticulate edges, three to four times as long as the shell. An +inner thin prolongation of the horn descends vertically nearly to the +mouth, and bears on its basal end three verticils of branched spines, each +verticil with three divergent forked spines (fig. 1_a_). Pores regular, +circular, in the subspherical abdomen three times as large as in the +hemispherical thorax. The constricted mouth is scarcely broader than the +thorax. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.03, _c_ 0.16; +breadth _a_ 0.03, _b_ 0.06, _c_ 0.16. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +Genus 621. _Lophocorys_,[238] Haeckel, 1881, Prodromus, p. 434. + +_Definition._--#Theocorida# (vel Tricyrtida eradiata aperta), with ovate +abdomen, broader than the constricted mouth. Cephalis with two divergent +horns, or with a bunch of horns. + +{1421}The genus _Lophocorys_ differs from its ancestral form, _Theocorys_, +only in the armature of the cephalis, bearing either two divergent horns, +or a corona of several radial horns. In two species there are four horns on +the apex, a larger vertical (occipital) horn being surrounded by three +smaller, upwards divergent horns. + + +1. _Lophocorys astrocephala_, n. sp. (Pl. 69, fig. 9). + +Shell smooth, inversely ovate, with deep collar and slight lumbar +stricture. Length of the three joints = 3 : 7 : 6, breadth = 4 : 11 : 10. +Cephalis subspherical, stellate, densely covered with numerous (ten to +twenty or more) divergent, large, slenderly conical horns, the longest of +which reach the length of the shell. Thorax campanulate, with small, +regular, circular pores. Abdomen tapering towards the constricted mouth, in +the upper half with the same pores, in the lower half with smaller, scarce +pores, or nearly hyaline. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.07, _c_ 0.06; +breadth, _a_ 0.04, _b_ 0.11, _c_ 0.1. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +2. _Lophocorys acanthocephala_, Haeckel. + + _Eucyrtidium acanthocephalum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 70, Taf. ix. fig. 8. + +Shell rough, bottle-shaped, with two slight strictures. Length of the three +joints = 5 : 11 : 7, breadth = 4 : 12 : 10. Cephalis conical, with a large +pyramidal horn of the same length, and three smaller divergent accessory +horns at the base of the three edges of the latter. Thorax campanulate, +nearly as long as the tapering abdomen (which in the figure of Ehrenberg is +broken off). Pores regular, circular, quincuncial. + +_Dimensions._--Length of the three joints, _a_ 0.05, _b_ 0.11, _c_ 0.07; +breadth, _a_ 0.04, _b_ 0.12, _c_ 0.1. + +_Habitat._--Fossil in Barbados. + + +3. _Lophocorys bicornis_, Haeckel. + + _Eucyrtidium bicorne_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 70, Taf. xi. fig. 7. + +Shell smooth, almost spindle-shaped, with two slight strictures. Length of +the three joints = 2 : 8 : 3, breadth = 3 : 5 : 4. Cephalis hemispherical, +with two stout, pyramidal, divergent horns of twice the length. Thorax +ovate, with seven to eleven transverse rows of small, regular, circular +pores (often very scarce in the upper half). Abdomen with two to four +transverse rows of the same pores. Mouth constricted, half as broad as the +thorax. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.08, _c_ 0.03; +breadth, _a_ 0.03, _b_ 0.05, _c_ 0.04. + +_Habitat._--Fossil in Barbados. + + +{1422}4. _Lophocorys quadricornis_, n. sp. + +Shell rough, slenderly ovate, with two distinct strictures. Length of the +three joints = 2 : 4 : 2, breadth = 2 : 4 : 3. Cephalis ovate, with four +very stout, three-sided prismatic horns; the largest is as long as the +thorax and vertical upon the apex, the three smaller are as long as the +cephalis and diverge upwards from the base of the former. Thorax ovate, +with large, irregular, roundish pores, which are three to four times as +broad as the small, circular pores of the first and the third joint. +Constricted mouth half as broad as the thorax. + +_Dimensions._--Length of the three joints, _a_ 0.045, _b_ 0.085, _c_ 0.04; +breadth, _a_ 0.035, _b_ 0.075, _c_ 0.06. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +5. _Lophocorys bovicornis_, n. sp. (Pl. 69, fig. 12). + +Shell rough, subovate, with two deep strictures. Length of the three joints += 1 : 2 : 3, breadth = 1 : 3 : 4. Cephalis subspherical, with two +divergent, curved horns of different lengths. Thorax campanulate, with +small, circular pores. Abdomen subspherical, truncate at both poles, twice +as broad as the constricted mouth, thorny, with very large, circular pores, +four to six times as broad as those of the smaller thorax. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.06, _c_ 0.09; +breadth, _a_ 0.04, _b_ 0.09, _c_ 0.12. + +_Habitat._--Central Pacific, Station 270, depth 2925 fathoms. + + + +Genus 622. _Theocampe_,[239] n. gen. + +_Definition._--#Theocorida# (vel Tricyrtida eradiata aperta) with ovate +abdomen, broader than the constricted mouth. Cephalis without horn. + +The genus _Theocampe_ differs from the two preceding genera in the absence +of horns on the cephalis, and may, therefore be derived from _Theocorys_ by +reduction of the apical horn. It bears to the latter the same relation as +_Tricolocampe_ does to _Theocyrtis_. + + + +Subgenus 1. _Theocampana_, Haeckel. + +_Definition._--Pores of the thorax and the abdomen of nearly equal size and +similar form. + + +1. _Theocampe ehrenbergii_, Haeckel. + + _Dictyomitra ehrenbergii_, Zittel, 1876, Zeitschr. d. deutsch. geol. + Gesellsch., p. 82, Taf ii. fig. 5. + +Shell ovate, smooth. Length of the three joints = 2 : 3 : 13, breadth = +4 : 7 : 12. Cephalis hemispherical. Thorax truncate, conical. Abdomen +inflated, nearly spherical, twice as broad as the constricted mouth. Pores +of nearly equal size and form, small, regular, circular. + +{1423}_Dimensions._--Length of the three joints, _a_ 0.014, _b_ 0.018, _c_ +0.076; breadth, _a_ 0.023, _b_ 0.044, _c_ 0.073. + +_Habitat._--Fossil in the chalk of Northern Germany; Brunswick (Zittel). + + +2. _Theocampe pirum_, Haeckel. + + _Eucyrtidium pirum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 72, Taf. x. fig. 14. + + _Eucyrtidium excellens_, Buetschli, 1882, Zeitschr. f. wiss. Zool., vol. + xxxvi. p. 540, Taf. xxxiii. fig. 31. + +Shell ovate, smooth. Length of the three joints = 3 : 5 : 15, breadth = +6 : 10 : 16. Cephalis hemispherical. Thorax truncate conical. Abdomen +inflated, subspherical, three times as broad as the constricted mouth. +Pores of nearly equal size, regular, circular in the thorax alternating, in +the abdomen disposed in five to six transverse, widely distant rows. + +_Dimensions._--Length of the three joints, _a_ 0.015, _b_ 0.025 _c_ 0.075; +breadth, _a_ 0.03, _b_ 0.05, _c_ 0.08. + +_Habitat._--Fossil in the Tertiary rocks of Barbados. + + +3. _Theocampe stenostoma_, n. sp. (Pl. 66, fig. 23). + +Shell about ovate, smooth. Length of the three joints = 3 : 4 : 3, breadth += 6 : 8 : 9. Cephalis hemispherical, large. Thorax and abdomen short, +barrel-shaped. Both strictures deep. Abdomen three times as broad as the +constricted mouth. Pores of equal size, regular, circular, disposed in +oblique rows. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.04, _c_ 0.03; +breadth, _a_ 0.06, _b_ 0.08, _c_ 0.09. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +4. _Theocampe nucula_, Haeckel. + + _Eucyrtidium nucula_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 29, Taf. vii. fig. 19. + +Shell nearly ovate, rough. Length of the three joints = 3 : 5 : 3, breadth += 4 : 7 : 6. Cephalis hemispherical, large. Thorax and abdomen inflated. +Both strictures deep. Thorax broader than the short abdomen, and twice as +broad as the constricted mouth. Pores of equal size, regular, circular, +regularly disposed in transverse rows: three in the cephalis, six in the +thorax, and three in the abdomen. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.05, _c_ 0.03; +breadth, _a_ 0.04, _b_ 0.07, _c_ 0.06. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms; also fossil +in Barbados. + + +5. _Theocampe cryptoprora_, Haeckel. + + _Eucyrtidium cryptoprora_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 291, Taf. vii. fig. 14. + +Shell ovate, thin-walled, smooth, without external strictures, but with two +distinct internal annular septa. Length of the three joints = 2 : 7 : 4, +breadth = 3 : 7 : 6. Cephalis, large, subspherical, {1424}hyaline; its +lower half hidden in the upper part of the campanulate thorax. Mouth little +constricted, nearly as broad as the truncate abdomen. All pores equal, +small, regular, circular. + +_Dimensions._--Length of the three joints, _a_ 0.025, _b_ 0.07, _c_ 0.04; +breadth, _a_ 0.03, _b_ 0.07, _c_ 0.06. + +_Habitat._--Tropical Pacific, Stations 225 to 265, in various depths. + + +6. _Theocampe ovulum_, n. sp. + +Shell perfectly ovate, thick-walled, smooth, without external strictures, +but with two broad, internal septa. Length of the three joints = +2 : 3 : 10, breadth = 3 : 6 : 8. Cephalis and thorax together obtuse, +conical, with obliquely ascending pores. Abdomen inflated, twice as broad +as the constricted mouth, with ten to twelve transverse rows of pores. All +pores equal, small, regular, circular. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.03, _c_ 0.1; +breadth, _a_ 0.03, _b_ 0.06, _c_ 0.08. + +_Habitat._--Fossil in Tertiary rocks of Barbados and Sicily. + + +7. _Theocampe cassis_, Haeckel. + + _Eucyrtidium cassis_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 291, Taf. vii. fig. 20. + +Shell bottle-shaped, thin-walled, with slight collar, but deep lumbar +stricture. Length of the three joints = 3 : 8 : 6, breadth = 2 : 7 : 7. +Cephalis ovate. Thorax campanulate. Abdomen inflated, twice as broad as the +constricted mouth. Pores equal, regular, circular, disposed in quincuncial +rows. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.08. _c_ 0.06; +breadth, _a_ 0.02, _b_ 0.07, _c_ 0.07. + +_Habitat._--Tropical Pacific (Philippines), Station 206, depth 2100 +fathoms. + + + +Subgenus 2. _Theocamptra_, Haeckel. + +_Definition._--Pores of the thorax and the abdomen of different sizes or +dissimilar forms. + + +8. _Theocampe sphaerothorax_, n. sp. (Pl. 66, fig. 25). + +Shell almost ovate, rough. Length of the three joints = 2 : 5 : 10, breadth += 3 : 8 : 8. Cephalis hemispherical. Thorax nearly spherical, truncate. +Abdomen ovate, twice as broad as the constricted mouth. Pores subregular, +circular, quincuncially disposed, in the abdomen twice as broad as in the +thorax, and four times as broad as in the cephalis. + +_Dimensions._--Length of the three joints, _a_ 0.025, _b_ 0.05, _c_ 0.1; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.08. + +_Habitat._--Central Pacific, Stations 263 to 274, depth 2350 to 2925 +fathoms. + + +{1425}9. _Theocampe versipellis_, Haeckel. + + _Eucyrtidium versipellis_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 72, Taf. xi. fig. 14. + +Shell slenderly ovate, rough. Length of the three joints = 3 : 5 : 13, +breadth = 4 : 8 : 9. Cephalis subspherical, without pores. Thorax +hemispherical. Abdomen inflated, twice as broad as the constricted mouth. +Pores subregular, circular, quincuncially disposed, in the abdomen three +times as broad as in the thorax. + +_Dimensions._--Length of the three joints, _a_ 0.025, _b_ 0.05, _c_ 0.13; +breadth, _a_ 0.04, _b_ 0.08, _c_ 0.09. + +_Habitat._--Fossil in Barbados. + + +10. _Theocampe megalopora_, Haeckel. + + _Eucyrtidium megaloporum_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 291, Taf. vii. fig. 19. + +Shell almost ovate, with two distinct strictures. Length of the three +joints = 2 : 6 : 3, breadth = 3 : 6 : 4. Cephalis hemispherical. Thorax +ovate, inflated. Abdomen inversely ovate, two to three times as broad as +the constricted mouth. Pores subregular, circular, quincuncially disposed, +twice as broad in the large thorax as in the smaller abdomen. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.03; +breadth, _a_ 0.03, _b_ 0.06, _c_ 0.04. + +_Habitat._--Central Pacific, Station 267, depth 2700 fathoms. + + +11. _Theocampe collaris_, n. sp. (Pl. 66, fig. 18). + +Shell almost ovate, with two distinct strictures. Length of the three +joints = 3 : 3 : 6, breadth = 4 : 5 : 7. Cephalis obtuse conical, with five +or six transverse rows of small pores. Thorax truncate conical, with +longitudinal furrows, each of which contains a single pore. Abdomen +inflated, with five or six distant, transverse rows of small, circular +pores. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.03, _c_ 0.06; +breadth, _a_ 0.04, _b_ 0.05, _c_ 0.07. + +_Habitat._--South Pacific, Station 295, depth 1500 fathoms. + + +12. _Theocampe gemmata_, Haeckel. + + _Eucyrtidium gemmatum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 70, Taf. x. fig. 6. + +Shell slenderly ovate, smooth, with two internal annular septa. Length of +the three joints = 1 : 1 : 4, breadth = 1 : 2 : 3. Cephalis campanulate, +nearly as large as the truncate, conical thorax, both with small, +irregular, obliquely descending pores. Abdomen broader, twice as broad as +the constricted mouth, with numerous longitudinal ribs, alternating with +single rows of small, circular pores. (This and the following allied +species approach to _Cycladophora_, by the abdominal ribs.) + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.02, _c_ 0.07; +breadth, _a_ 0.025, _b_ 0.035, _c_ 0.045. + +_Habitat._--Fossil in Barbados. + + +{1426}13. _Theocampe costata_, n. sp. (Pl. 66, fig. 24). + +Shell almost ovate, with two sharp strictures. Length of the three joints = +2 : 4 : 8, breadth = 3 : 5 : 7. Cephalis hemispherical. Thorax twice as +large, also hemispherical, both with regular, circular, quincuncial pores. +Abdomen broader, with numerous longitudinal ribs, alternating with +longitudinal rows of larger pores. Mouth constricted, half as broad as the +thorax. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.08; +breadth, _a_ 0.03, _b_ 0.05, _c_ 0.07. + +_Habitat._--Indian Ocean, Sunda Straits (Rabbe), surface. + + +14. _Theocampe cryptocephala_, Haeckel. + + _Eucyrtidium cryptocephalum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 70, Taf. xi. fig. 11. + +Shell ovate, rough, with two distinct strictures. Length of the three +joints = 1 : 2 : 4, breadth = 1 : 4 : 5. Cephalis subspherical, its lower +half hidden in the campanulate thorax. Abdomen subspherical, twice as broad +as the constricted mouth. Pores subregular, circular, quincuncial, twice as +broad in the abdomen as in the thorax. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.07; +breadth, _a_ 0.025, _b_ 0.07, _c_ 0.09. + +_Habitat._--Fossil in Barbados. + + + +Subfamily 2. THEOCAPSIDA, Haeckel, 1881, Prodromus, p. 436. + +_Definition._--#Theocyrtida# with the basal mouth of the shell fenestrated +(vel Tricyrtida eradiata clausa). + + + +Genus 623. _Theocapsa_,[240] Haeckel, 1881, Prodromus, p. 436. + +_Definition._--#Theocapsida# (vel Tricyrtida eradiata clausa), with an +apical horn, and a terminal lattice-plate on the mouth. + +The genus _Theocapsa_, and the two following genera, represent together the +small subfamily of Theocapsida, or of those Tricyrtida in which the mouth +is closed by a lattice-plate, and external radial appendages are wanting. +_Theocapsa_ may be derived from _Theocorys_ by fenestration of the +constricted mouth. + + + +Subgenus 1. _Theocapsetta_, Haeckel. + +_Definition._--Thorax of about the same size as the abdomen, or somewhat +larger; pores of both nearly equal in size and similar in form. + + +{1427}1. _Theocapsa aristotelis_, n. sp. (Pl. 66, fig. 6). + +Shell subovate, smooth, with two distinct strictures. Length of the three +joints = 2 : 6 : 7, breadth = 3 : 8 : 8. Cephalis hemispherical, with a +conical, slender horn of about the same length. Thorax and abdomen nearly +equal in size, thin-walled, smooth, with small, regular, circular pores of +equal size. Basal pole rounded. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.07; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.08. + +_Habitat._--Mediterranean (Gibraltar), Atlantic (Canary Islands), surface. + + +2. _Theocapsa plinii_, n. sp. + +Shell subovate, smooth, with two indistinct strictures. Length of the three +joints = 2 : 5 : 6, breadth = 3 : 7 : 7. Cephalis hemispherical, with a +pyramidal, thick horn of about the same length. Thorax and abdomen of +nearly equal size, thick-walled, rough, with large, regular, circular, +double-edged pores of equal size (twice as large and half as numerous as in +the similar preceding species). + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.05, _c_ 0.06; +breadth, _a_ 0.03, _b_ 0.07, _c_ 0.07. + +_Habitat._--Central Pacific, Stations 265 to 268, depth 2700 to 2900 +fathoms. + + +3. _Theocapsa democriti_, n. sp. (Pl. 66, fig. 8). + +Shell slender, ovate, spiny, with two distinct strictures. Length of the +three joints = 3 : 5 : 6, breadth = 4 : 7 : 7. Cephalis ovate, with +numerous slender horns of the same length. Thorax and abdomen with small, +irregular, roundish pores of nearly equal size, armed with scattered +slender spines, half as long as the cephalic horns. Basal pole +hemispherical, rounded. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.05, _c_ 0.06; +breadth, _a_ 0.04, _b_ 0.07, _c_ 0.07. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +4. _Theocapsa galeni_, n. sp. + +Shell broadly ovate, spiny, with two deep strictures. Length of the three +joints = 2 : 7 : 6, breadth = 3 : 8 : 7. Cephalis hemispherical, with two +conical, divergent horns of the same length. Thorax and abdomen with large, +irregular, roundish pores of nearly equal size, armed with numerous short +spines, not larger than the pores. Basal pole conical, pointed. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.07, _c_ 0.06; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.07. + +_Habitat._--North Pacific, Station 253, depth 3125 fathoms. + + + +Subgenus 2. _Theocapsilla_, Haeckel. + +_Definition._--Thorax of about the same size as the abdomen, or somewhat +larger; pores of the two different in size or form. + + +{1428}5. _Theocapsa wottonis_, n. sp. (Pl. 66, fig. 11). + +Shell subovate, rough, with two deep strictures. Length of the three joints += 3 : 7 : 5, breadth = 3 : 9 : 8. Cephalis subspherical, with regular, +circular, hexagonally-framed pores, and with a stout pyramidal horn of the +same length. Thorax conical, with subregular, circular, double-edged pores. +Abdomen hemispherical, smaller and thinner walled, with irregular, somewhat +oblong pores. Basal pole rounded. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.07, _c_ 0.05; +breadth, _a_ 0.03, _b_ 0.09, _c_ 0.08. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +6. _Theocapsa gessneri_, n. sp. + +Shell broadly ovate, with two deep strictures. Length of the three joints = +3 : 9 : 5, breadth = 4 : 10 : 4. Cephalis hemispherical, with a slender, +conical horn of the same length. Thorax subspherical, with small, regular, +circular pores. Abdomen inversely conical, with few large, somewhat oblong +pores. Basal pole acute. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.09, _c_ 0.05; +breadth, _a_ 0.04, _b_ 0.1, _c_ 0.04. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +7. _Theocapsa aldrovandi_, n. sp. + +Shell slender, inversely ovate, with two slight strictures. Length of the +three joints = 3 : 8 : 14, breadth = 4 : 11 : 8. Cephalis subglobular, with +a conical horn of the same length. Thorax also subglobular, papillate, with +regular, circular, hexagonally-framed pores. Abdomen inversely conical, +slender, with very small and numerous, subregular, circular pores. Basal +pole ovate, pointed. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.08, _c_ 0.14; +breadth, _a_ 0.04, _b_ 0.11, _c_ 0.08. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +8. _Theocapsa malpighii_, n. sp. (Pl. 66, fig. 15). + +Shell inversely ovate, with two distinct strictures. Length of the three +joints = 3 : 8 : 11, breadth = 4 : 9 : 8. Cephalis hemispherical, with a +conical horn of the some length Thorax hemispherical, thorny, with very +small circular pores, surrounded by large, regular, hexagonal frames. +Abdomen inversely campanulate, with larger circular pores, and longitudinal +ribs. Basal pole blunt, conical. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.08, _c_ 0.11, +breadth, _a_ 0.04, _b_ 0.09, _c_ 0.08. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + + +Subgenus 3. _Theocapsomma_, Haeckel. + +_Definition._--Thorax much smaller than the abdomen, pores of the two +nearly equal in size and similar in form. + + +{1429}9. _Theocapsa linnaei_, n. sp. (Pl. 66, fig. 13). + +Shell slender, subcylindrical, rough with two slight strictures. Length of +the three joints = 1 : 3 : 6, breadth = 1 : 4 : 4. Cephalis hemispherical, +with a pyramidal horn of twice the length (sometimes, as in the specimen +figured, one or two small accessory horns occur at its base). Thorax +hemispherical, thick-walled. Abdomen nearly cylindrical, twice as long as +the thorax, thin-walled, with a hemispherical, rounded basal pole. The +specimen figured is an abnormal one, with some deformities on the irregular +abdomen; in numerous other specimens the abdomen is cylindrical, regular. +Pores of the thorax and abdomen equal, very small and numerous, regular, +circular, three to four times as broad as the bars. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.05 to 0.06, _c_ +0.1 to 0.12; breadth, _a_ 0.03, b 0.06 to 0.07, _c_ 0.07 to 0.08. + +_Habitat._--Cosmopolitan; Atlantic, Indian, and Pacific Oceans; many +Stations at various depths. + + +10. _Theocapsa forskalii_, n. sp. (Pl. 66, fig. 9). + +Shell slender, subcylindrical, smooth, with two slight strictures. Length +of the three joints = 1 : 1 : 3, breadth = 1 : 2 : 2. Cephalis +hemispherical, with a conical horn of half the length. Abdomen three times +as long as the thorax, of the same breadth, with the same irregular, +roundish pores, large and small intermingled. Basal pole rounded. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.03, _c_ 0.09; +breadth, _a_ 0.03, _b_ 0.06, _c_ 0.06. + +_Habitat._--North Atlantic, Canary Islands, Station 353, depth 2965 +fathoms. + + +11. _Theocapsa wolffii_, n. sp. (Pl. 66, fig. 14). + +Shell slender, spindle-shaped very thick-walled, rough, without external +strictures, but with two broad internal girdles. Length of the three joints += 2 : 3 : 15, breadth = 4 : 5 : 7. Cephalis with a short horn of the same +length, conical. Abdomen five times as long as the thorax, with the same +subregular, circular pores. Basal pole inversely conical, with some larger, +elongate pores. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.03, _c_ 0.15; +breadth, _a_ 0.04, _b_ 0.05, _c_ 0.07. + +_Habitat._--Mediterranean, Crete, depth 1620 fathoms (Spratt). + + +12. _Theocapsa pallasii_, n. sp. + +Shell subovate, thorny, with two slight strictures. Length of the three +joints = 1 : 2 : 3, breadth = 1 : 2 : 3. Cephalis ovate, with a pyramidal +horn of the same length. Thorax and abdomen with subregular, circular pores +of medium size. Basal pole hemispherical. (Differs from _Theocapsa +muelleri_, Pl. 66, fig. 7, mainly in the larger number and smaller size of +the regular, quincuncial pores.) + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.06, _c_ 0.09; +breadth, _a_ 0.03, _b_ 0.06, _c_ 0.09. + +_Habitat._--Tropical Atlantic, Station 342, depth 1445 fathoms. + + + +{1430}Subgenus 4. _Theocapsura_, Haeckel. + +_Definition._--Thorax much smaller than the abdomen, pores of the two +different in size or form. + + +13. _Theocapsa lamarckii_, n. sp. (Pl. 66, fig. 16). + +Shell slenderly ovate, rough, with two distinct strictures. Length of the +three joints = 1 : 2 : 7, breadth = 1 : 4 : 5. Cephalis subspherical, with +a conical horn of twice the length. Thorax conical, with regular, circular +pores. Abdomen three times longer, with subregular, hexagonal pores of +twice the size. Basal pole hemispherical, with very large, irregular, +roundish pores. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.05, _c_ 0.14; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.1. + +_Habitat._--Indian Ocean, Madagascar (Rabbe), surface. + + +14. _Theocapsa cuvieri_, n. sp. (Pl. 66, fig. 10). + +Shell slenderly spindle-shaped, thorny, with two slight strictures. Length +of the three joints = 1 : 3 : 6, breadth = 1 : 3 : 3. Cephalis +subspherical, with a conical horn of the same length. Thorax conical, +spiny, with regular, circular, double-edged pores. Abdomen thinner-walled, +inversely conical, with irregular, roundish pores. Basal pole acute, with a +bunch of larger spines. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.05, _c_ 0.12; +breadth, _a_ 0.02, _b_ 0.05, _c_ 0.06. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +15. _Theocapsa baerii_, n. sp. + +Shell slenderly spindle-shaped, smooth with two indistinct strictures. +Length of the three joints = 1 : 2 : 8, breadth = 2 : 3 : 4. Cephalis +hemispherical, with a thick conical horn of the same length. Abdomen four +times as long as the thorax. Pores in the thorax small and numerous, +regular, circular, in the abdomen twice as large, and irregularly roundish. +Basal pole inversely conical, acute. (Differs from _Theocapsa wolffii_, Pl. +66, fig. 14, mainly in the shape of the pores.) + +_Dimensions._--Length of the three joints, _a_ 0.015, _b_ 0.03, _c_ 0.12; +breadth, _a_ 0.03, _b_ 0.04, _c_ 0.06. + +_Habitat._--North Pacific, Station 241, depth 2300 fathoms. + + +16. _Theocapsa rathkei_, n. sp. + +Shell slenderly conical, with two slight strictures. Length of the three +joints = 1 : 2 : 10, breadth = 2 : 4 : 15. Cephalis small, with a large, +conical horn of three times the length. Thorax small, thorny, with small +irregular, roundish pores. Abdomen very large, as long and as broad as the +thorax, with irregular polygonal or roundish, very large pores, the margin +of which is finely denticulate. Basal pole truncate, rounded. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.05, _c_ 0.2; +breadth, _a_ 0.04, _b_ 0.08, _c_ 0.3. + +_Habitat._--Fossil in Barbados. + + +{1431}17. _Theocapsa schwannii_, n. sp. + +Shell slenderly ovate, or pear-shaped, with two distinct strictures. Length +of the three joints = 1 : 2 : 7, breadth = 2 : 4 : 7. Cephalis +subspherical, small, with a stout, pyramidal horn of three times the +length. Cavity of the thorax subspherical, its thick wall with small, +regular, circular, hexagonally-framed pores. Abdomen very thick-walled, +with crested bars, and very large, irregular, roundish pores. Basal pole +rounded, truncate. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.14, +breadth, _a_ 0.04, _b_ 0.08, _c_ 0.14. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +18. _Theocapsa muelleri_, n. sp. (Pl. 66, fig. 7). + +Shell slenderly ovate, or pear-shaped, spiny, with two indistinct +strictures. Length of the three joints = 1 : 2 : 3, breadth = 1 : 2 : 3. +Cephalis ovate, with a stout, pyramidal horn of the same length, and with a +variable number of smaller accessory horns. Pores irregular, roundish, +three to four times as broad in the inflated abdomen as in the thorax. +Basal pole hemispherical, spiny. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.05, _c_ 0.09; +breadth, _a_ 0.03, _b_ 0.07, _c_ 0.09. + +_Habitat._--Central Pacific, Stations 270 to 274, depth 2350 to 2925 +fathoms. + + +19. _Theocapsa sarsii_, n. sp. + +Shell pear-shaped, with two indistinct strictures. Length of the three +joints = 1 : 1 : 3, breadth = 1 : 2 : 4. Cephalis with a thick horn of the +same length, conical. Abdomen subspherical, very thick-walled, its pores +regular, circular, twice as broad as the bars, and three times as broad as +those of the thorax. Basal pole flat, rounded. + +_Dimensions._--Length of the three joints, _a_ 0.04, _b_ 0.05, _c_ 0.12; +breadth, _a_ 0.05, _b_ 0.11, _c_ 0.15. + +_Habitat._--Fossil in Barbados. + + +20. _Theocapsa darwinii_, n. sp. (Pl. 66, fig. 12). + +Shell pear-shaped, with two distinct strictures. Length of three joints = +1 : 1 : 5, breadth = 1 : 2 : 5. Cephalis hemispherical, with a conical horn +of twice the length. Thorax campanulate, with small, regular, circular +pores. Abdomen broad, ovate, with larger, regular, circular, +hexagonally-framed pores. Basal pole hemispherical. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.04, _c_ 0.2; +breadth, _a_ 0.04, _b_ 0.08, _c_ 0.2. + +_Habitat._--Central Pacific, Stations 263 to 274, depth 2350 to 2925 +fathoms. + + + +Genus 624. _Tricolocapsa_,[241] Haeckel. + +_Definition._--#Theocapsida# (vel Tricyrtida eradiata clausa) without +apical horn, with a terminal lattice-plate on the mouth. + +{1432}The genus _Tricolocapsa_ differs from the preceding _Theocapsa_ in +the loss of the apical horn, and exhibits therefore to it the same relation +that _Theocampe_ bears to _Theocorys_. In some species (Pl. 66, figs. 1, 3) +a small tube begins to be developed on the cephalis, and these may perhaps +be separated as a peculiar genus, _Tricolopera_. + + + +Subgenus 1. _Tricolocapsula_, Haeckel. + +_Definition._--Thorax of about the same size as the abdomen, or larger. + + +1. _Tricolocapsa theophrasti_, n. sp. (Pl. 66, fig. 1). + +Shell slenderly ovate, with two slight strictures. Length of the three +joints = 2 : 8 : 5, breadth = 3 : 7 : 5. Cephalis hemispherical, with a +larger, tube-like, cervical pore at the collar stricture. Thorax very +thick-walled, with irregular, roundish, double edged pores, smaller than +the bars between them. Abdomen smaller, inversely campanulate-conical, with +very irregular pores. Basal pole acute. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.08, _c_ 0.05; +breadth, _a_ 0.03, _b_ 0.07, _c_ 0.05. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +2. _Tricolocapsa dioscoridis_, n. sp. (Pl. 66, fig. 3). + +Shell short and broad, with two deep strictures. Length of the three joints += 3 : 5 : 4, breadth = 4 : 7 : 5. Cephalis hemispherical, with a larger, +tube-like, cervical pore above the collar stricture. Thorax very broad, +with irregular, large and spare, roundish pores. Abdomen much smaller, +inversely conical, with smaller pores. Basal pole obtuse. + +_Dimensions._--Length of the three joints, _a_ 0.03, _b_ 0.05, _c_ 0.04; +breadth, _a_ 0.04, _b_ 0.07, _c_ 0.05. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + +3. _Tricolocapsa linnaei_, n. sp. (Pl. 66, fig. 5). + +Shell short and broad, with two deep strictures. Length of the three joints += 1 : 4 : 2, breadth = 1 : 4 : 2. Cephalis hemispherical. Thorax +thick-walled, inflated, with subregular, circular, double-edged pores. +Abdomen much smaller, thin-walled, with irregular, polygonal pores. Basal +pole hemispherical, rounded. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.08, _c_ 0.05; +breadth, _a_ 0.03, _b_ 0.08, _c_ 0.05. + +_Habitat._--South Pacific, Station 295, depth 1500 fathoms. + + +{1433}4. _Tricolocapsa decandollei_, n. sp. (Pl. 66, fig. 4). + +Shell subovate, with two sharp strictures. Length of the three joints = +2 : 2 : 2, breadth = 3 : 4 : 3.5. Cephalis campanulate. Thorax broader, +ring-shaped. Abdomen inversely hemispherical. All three joints of the same +length, thick-walled, with the same regular and peculiar reticulation, the +small circular pores being surrounded by square, elevated frames. + +_Dimensions._--Length of the three joints, _a_ 0.07, _b_ 0.07, _c_ 0.07; +breadth, _a_ 0.10, _b_ 0.14, _c_ 0.12. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + + +Subgenus 2. _Tricolocapsium_, Haeckel. + +_Definition._--Thorax much smaller than the abdomen. + + +5. _Tricolocapsa brownii_, n. sp. + +Shell ovate, very thick-walled, with two indistinct strictures. Length of +the three joints = 2 : 4 : 7, breadth = 3 : 7 : 10. Cephalis flat, +hemispherical. Thorax truncate, conical. Abdomen inflated, inversely +hemispherical. Pores regular, circular, of the same breadth as the bars, +hexagonally-framed, twice as large in the abdomen as in the thorax. Basal +pole rounded. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.04, _c_ 0.07; +breadth, _a_ 0.03, _b_ 0.07, _c_ 0.1. + +_Habitat._--Fossil in Barbados. + + +6. _Tricolocapsa schleidenii_, n. sp. (Pl. 66, fig. 2). + +Shell subconical, with two deep strictures. Length of the three joints = +2 : 3 : 6, breadth = 3 : 5 : 6. Cephalis subspherical. Pores subregular, +circular, arranged in transverse girdles, three in the broad thorax, six in +the subglobular abdomen. Basal pole rounded. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.03, _c_ 0.06; +breadth, _a_ 0.03, _b_ 0.05, _c_ 0.06. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + + +Genus 625. _Phrenocodon_,[242] n. gen. + +_Definition._--#Theocapsida# (vel Tricyrtida eradiata clausa) with an +apical horn, and a lattice-plate between thorax and abdomen. + +The genus _Phrenocodon_ differs from the two preceding genera in the +remarkable circumstance, that the basal lattice-plate closes not the +terminal mouth itself, but the {1434}constricted opening between thorax and +abdomen. It may therefore be regarded as a _Sethocapsa_, which has +developed a third, open, abdominal joint. The cephalis bears an apical +horn. + + +1. _Phrenocodon clathrostomium_, n. sp. (Pl. 70, figs. 7, 8). + +Shell campanulate-conical, with two deep strictures. Length of the three +joints = 2 : 6 : 3, breadth = 3 : 10 : 14. Cephalis hemispherical, with an +oblique curved horn of the same length. Thorax subconical, with polygonal, +roundish pores, increasing in size towards the girdle. A perfect +fenestrated diaphragm, with irregular, roundish pores of very different +sizes, separates the thorax from the abdomen. The latter is composed of +three parallel, circular rings, which are connected by fifteen to twenty +radial beams. As the middle ring is larger than the two others, the beams +between the large quadrangular pores are divergent in the upper, convergent +in the lower girdle. Short prolongations of the divergent beams form a +coronal around the middle ring (compare fig. 7 profile, fig. 8 from below). + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.03; +breadth, _a_ 0.03, _b_ 0.1, _c_ 0.14. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +2. _Phrenocodon diaphragma_, n. sp. + +Shell campanulate-conical, very similar to that of the preceding species, +but with abdomen and proportions different. Length of the three joints = +1 : 3 : 2, breadth = 1 : 4 : 4. Abdomen cylindrical, with two or three +transverse rows of large quadrangular meshes (fifteen to twenty in each +row), without the characteristic inflexion of the preceding species, and +without the coronal. + +_Dimensions._--Length of the three joints, _a_ 0.02, _b_ 0.06, _c_ 0.034; +breadth, _a_ 0.02, _b_ 0.08, _c_ 0.08. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +---- + + +Section IV. STICHOCYRTIDA, Haeckel, 1862, Monogr. d. Radiol., p. 280, 312 +(Pls. 75-80). + + _Stichocyrtida et Tetracyrtida_, Haeckel, 1881, Prodromus, p. 437, 438. + +_Definition._--#Cyrtoidea# polythalamia, with annulated shell, divided by +three to six or more transverse, horizontal constrictions, into four to +seven or more annular joints. (The first joint represents the cephalis, the +second the thorax, the third the abdomen, all the following joints together +a post-abdomen.) + +{1435}_Synopsis of the three Families and six Subfamilies of +Stichocyrtida._ + + Family LXVIII. Podocampida. } Mouth open, Stichopilida. + Three radial apophyses. } + } Mouth closed, Stichoperida. + + Family LXIX. Phormocampida. } Mouth open, Stichophormida. + Numerous radial apophyses. } + } Mouth closed, Stichophaenida. + + Family LXX. Lithocampida. } Mouth open, Stichocorida. + No radial apophyses. } + } Mouth closed, Stichocapsida. + + + +Family LXVIII. #PODOCAMPIDA#, n. fam. + + _Artopilida et Artoperida, Stichopilida et Stichoperida_, Haeckel, 1881, + Prodromus, p. 437-439. + +_Definition._--#Stichocyrtida# triradiata. (#Cyrtoidea# with an annulated +shell, divided by three or more transverse constrictions into four or more +annular joints, and bearing three radial apophyses). + +The family #Podocampida# comprises those #Cyrtoidea# in which the +lattice-shell is composed of numerous (four to eight or more) annular +joints, and bears three external radial apophyses. It may be divided into +two subfamilies, differing in the shape of the terminal mouth. This is a +simple wide opening in the Stichopilida (and the united Artopilida), closed +by a lattice-plate in the Stichoperida (and the united Artoperida). The +phylogenetic origin of the Podocampida may be found in the Podocyrtida (p. +1314). + +Very few forms only of the Podocampida were hitherto known, viz., +_Stichopilium_ (_Pterocodon_) _davisianum_, and three fossil species from +Barbados, figured by Ehrenberg; _Artopera loxia_ (united by him with +_Lithornithium_), and two species of _Pteropilium_ (_sphinx_ and _bombus_, +both united by him with the three-jointed _Pterocanium_). In general, the +triradiate Stichocyrtida are much rarer and much poorer in specific forms +than the triradiate Tricyrtida, their ancestors. We have observed +altogether only forty-four species, thirty Stichopilida, and fourteen +Stichoperida; the former are disposed among seven, the latter among three +genera. + +The three radial apophyses appear either as lateral ribs or prominent wings +in the thorax (Pl. 77, fig. 8-12), or as three terminal feet around the +mouth (Pl. 97, fig. 15). Sometimes the ribs are replaced by three radial +combs, or rows of spines, and these may be united by three divergent beams, +forming three vaulted bridges with numerous bows (Pl. 75, figs. 10, 11). +The lateral wings or ribs, as well as the terminal feet, are either solid +or fenestrated. + +{1436}_Synopsis of the Genera of Podocampida._ + + ------------------------------------------------------------------------- + I. Subfamily Stichopilida. + Mouth of the terminal joint a simple wide opening. + -------------------- + Three lateral appendices or wings (no terminal feet). + ------------------------------------------------------------------------- + Lateral wings are { Cephalis with + solid spines. { horn, 626. _Stichopilium_. + + { With horn, 627. _Artopilium_. + Lateral wings are { + latticed. { Without horn, 628. _Pteropilium_. + ------------------------------------------------------------------------- + Three terminal appendices or feet at the peristome (all with + cephalic horn). + ------------------------------------------------------------------------- + Three lateral ribs { Feet solid, 629. _Stichocampe_. + or crests prolonged { + into the three { Feet latticed, 630. _Stichopterium_. + terminal feet. { + + No lateral ribs. { Feet solid, 631. _Podocampe_. + Three terminal { + feet free. { Feet latticed, 632. _Stichopodium_. + ------------------------------------------------------------------------- + II. Subfamily Stichoperida. + Mouth of the terminal joint closed by a lattice-plate. + -------------------- + Last joint rounded, without a vertical basal spine (cephalis with horn). + ------------------------------------------------------------------------- + Three lateral solid ribs + (or rows of spines), 633. _Stichopera_. + + Three lateral latticed wings + (or rows of wings), 634. _Cyrtopera_. + ------------------------------------------------------------------------- + Last joint conical, pointed, with a vertical basal spine. + ------------------------------------------------------------------------- + Three lateral solid ribs + (cephalis with an apical horn), 635. _Artopera_. + + + +Subfamily 1. STICHOPILIDA, Haeckel, 1881, Prodromus, p. 439. + +_Definition._--#Podocampida# with the terminal mouth of the shell open (vel +Stichocyrtida triradiata aperta). + + + +Genus 626. _Stichopilium_,[243] Haeckel, 1881, Prodromus, p. 439. + +_Definition._--#Stichopilida# (vel Stichocyrtida triradiata aperta) with +three solid lateral ribs or wings, without terminal feet. Cephalis with a +horn. + +The genus _Stichopilium_ is the most primitive among all Stichocyrtida, and +represents perhaps the common ancestral form of this family. The shell is +composed of four or more joints (sometimes ten to twelve), has a wide open +terminal mouth, and three lateral solid wings or ribs (sometimes a little +latticed on the base). _Stichopilium_ may be derived from _Theopilium_ or +_Pterocorys_ by addition of new terminal joints. + + + +Subgenus 1. _Triacartus_, Haeckel, 1881, Prodromus, p. 437. + +_Definition._--Shell with three annular strictures, and four distinct +joints. + + +{1437}1. _Stichopilium cortina_, n. sp. + +Shell ovate, with three sharp strictures. Length of the four joints = +2 : 6 : 3 : 4. Cephalis subspherical, with a slender pyramidal horn of +twice the length. The three edges of the horn are prolonged into three +strong divergent ribs, along the three first joints, and into three free +conical lateral spines, directed downwards, on the end of the third joint. +The fourth joint is subcylindrical; its circular, terminal mouth half as +broad as the third joint, which is the broadest. Pores small, regular, +hexagonal, with thin bars. + +_Dimensions._--Length of the shell (with four joints) 0.15, breadth 0.08. +Length of the single joints, _a_ 0.02, _b_ 0.06, _c_ 0.03, _d_ 0.04. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +2. _Stichopilium costatum_, n. sp. + +Shell conical, or nearly pyramidal, with three distinct strictures. Length +of the four joints = 3 : 5 : 8 : 4. Cephalis subconical, with a stout +pyramidal horn of the same length. Thorax campanulate, with six +longitudinal ribs, from three of which in the middle arise three +horizontal, conical, free spines or wings, about as long as the cephalis. +The third large prismatic joint bears twelve parallel ribs, six new ribs +being intercalated between the six former. Fourth joint short, cylindrical, +without ribs, the wide open mouth not constricted, nearly as broad as the +third joint, which is the broadest. Pores small, irregular, polygonal, or +roundish. + +_Dimensions._--Length of the shell (with four joints) 0.2, breadth 0.12. +Length of the single joints, _a_ 0.03, _b_ 0.05, _c_ 0.08, _d_ 0.04. + +_Habitat._--North Pacific, Station 244 (off Japan), depth 2900 fathoms. + + +3. _Stichopilium bicorne_, n. sp. (Pl. 77, fig. 9). + +Shell conical, with three slight strictures. Length of the four joints = +4 : 14 : 5 : 3. Cephalis large, conical, with two stout pyramidal, +divergent horns of twice the length. From its base (in the middle of the +collar stricture) arise three internal, downwardly divergent ribs, which +are prolonged on the outside of the upper half of the thorax into three +stout, pyramidal, lateral spines (similar to the horns). The fourth joint, +with wide open mouth, was the broadest, but not fully developed in the +single specimen observed. Pores subregular, hexagonal, with thin bars. + +_Dimensions._--Length of the shell (with four joints) 0.02, breadth 0.09. +Length of the single joints, _a_ 0.02, _b_ 0.07, _c_ 0.025, _d_ 0.015. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +4. _Stichopilium davisianum_, Haeckel. + + _Pterocodon davisianus_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 298, Taf. ii. fig. 10. + + _Cycladophora davisiana_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 289, Taf. ii. fig. 11. + + _Eucyrtidium davisianum_, Haeckel, 1862, Monogr. d. Radiol., p. 328. + + _Pterocanium davisianum_, Haeckel, 1862, Monogr. d. Radiol., p. 332. + +Shell campanulate, conical, with three slight strictures. Length of the +four joints = 2 : 3 : 4 : 3. Cephalis hemispherical, with few small pores +and a short conical horn. Thorax campanulate, with {1438}larger circular +pores, and three recurved, divergent, lateral wings of the same length. +Third and fourth joints each with three transverse rows of very large +hexagonal pores. The similar form described by Ehrenberg as _Cycladophora +davisiana_, is either a mutilated specimen, or belongs to _Lithostrobus_. + +_Dimensions._--Length of the shell (with four joints) 0.12, breadth 0.08. +Length of the single joints, _a_ 0.02, _b_ 0.03, _c_ 0.04, _d_ 0.03. + +_Habitat._--North Atlantic, Greenland, depth 1000 to 1500 fathoms. + + +5. _Stichopilium campanulatum_, n. sp. (Pl. 77, fig. 11). + +Shell campanulate, with three slight strictures. Length of the four joints += 3 : 5 : 5 : 4. Cephalis subovate, with an internal rod-cross, and a stout +pyramidal horn of the same length. From the middle of the collar stricture +arise three divergent collar beams, which descend in the upper half of the +campanulate thorax as three divergent ribs, and are prolonged into three +free horizontal spines. (In the specimen figured these three wings are very +short; in another specimen, found afterwards, there were three solid, +pyramidal, horizontal spines, as long as the cephalic horn.) The third +joint is the broadest, of about the same length as the fourth. (The annular +septum between the two latter is by a mistake not figured). Pores +subregular, circular, hexagonally framed. + +_Dimensions._--Length of the shell (with four joints) 0.17, breadth 0.12. +Length of the single joints, _a_ 0.03, _b_ 0.05, _c_ 0.05, _d_ 0.04. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +6. _Stichopilium triserratum_, n. sp. + +Shell slenderly campanulate, with three deep strictures. Length of the four +joints = 2 : 4 : 6 : 3. Cephalis hemispherical, with a stout pyramidal horn +three times the length. The three edges of the horn are prolonged into +three strong prominent ribs along the three first joints; each rib bears a +series of stout, irregular, triangular teeth. The fourth joint is without +ribs; its constricted mouth is half as broad as the third (broadest) joint. +Pores subregular, circular. + +_Dimensions._--Length of the shell (with four joints) 0.15, breadth 0.08. +Length of the single joints, _a_ 0.02, _b_ 0.04, _c_ 0.06, _d_ 0.03. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + + +Subgenus 2. _Stichopilidium_, Haeckel. + +_Definition._--Shell with four or more annular strictures and five or more +joints. + + +7. _Stichopilium macropterum_, Haeckel. + + _Rhopalocanium varietas_, Bury, 1862, Polycystins of Barbados, pl. xvii. + fig. 7. + +Shell slenderly conical, with five deep strictures. Length of the six +joints = 2 : 5 : 4 : 3 : 3 : 6. Cephalis hemispherical, with a stout +conical horn of twice the length. Thorax campanulate, with {1439}three +large, triangular, widely divergent wings or ribbed solid spines, nearly as +long as the shell. The breadth of the joints increases gradually; the last +joint is the broadest, with wide open mouth. Pores subregular, circular. + +_Dimensions._--Length of the shell (with six joints) 0.23, breadth 0.1. +Length of the single joints, _a_ 0.02, _b_ 0.05, _c_ 0.04, _d_ 0.03, _e_ +0.03, _f_ 0.06. + +_Habitat._--Fossil in Barbados. + + +8. _Stichopilium pectinatum_, n. sp. + +Shell slenderly conical, with nine sharp strictures. All ten joints have +nearly equal length, and increase gradually in breadth; the last joint is +the broadest, and twice as long as each of the others, with wide open +mouth. Cephalis subspherical, with a conical horn of the same length. Each +joint (excepting the first and the last) bears three lateral, nearly +horizontal spines, and the bases of all the spines are connected by three +longitudinal, divergent ribs. Pores subregular, hexagonal. (Similar to +_Stichopera pectinata_, Pl. 75, fig. 11.) + +_Dimensions._--Length of the shell (with ten joints) 0.32, breadth 0.1. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +9. _Stichopilium thoracopterum_, n. sp. + +Shell slenderly ovate, twice as long as broad, with eleven slight annular +strictures. The twelve joints (excepting the second) are of nearly equal +length, or alternately longer and shorter. The eighth joint is the +broadest, one and a half times as broad as the slightly constricted mouth. +Cephalis small, hemispherical, with a pyramidal horn of twice the length. +Thorax (or second joint) campanulate, twice to three times as long as each +of the eleven other joints, with three longitudinal ribs, prolonged into +three divergent, slender, free spines. Pores small, regular, hexagonal. + +_Dimensions._--Length of the shell (with twelve joints) 0.22, breadth 0.11. +Length of each joint (on an average) 0.015 to 0.017, thorax 0.035. + +_Habitat._--South Pacific, Station 296, depth 1825 fathoms. + + + +Genus 627. _Artopilium_,[244] Haeckel, 1881, Prodromus, p. 437. + +_Definition._--#Stichopilida# (vel Stichocyrtida triradiata aperta) with +three latticed lateral ribs or wings, without terminal feet. Cephalis with +a horn. + +The genus _Artopilium_ (including also the genera _Trictenartus_, +_Pterocorythium_, _Stichopterygium_, and _Clathropyrgus_ of my Prodromus) +has a shell of the same form as the preceding _Stichopilium_, but it +differs in the fenestration of the three lateral ribs or wings, which in +the latter are solid. The limit between the two genera is often not +{1440}sharp. _Artopilium_ may be also derived from the three-jointed +_Dictyoceras_ by addition of new terminal joints. + + + +Subgenus 1. _Trictenartus_, Haeckel, 1881, Prodromus, p. 437. + +_Definition._--Shell with three annular strictures and four joints. + + +1. _Artopilium elegans_, n. sp. (Pl. 75, fig. 1). + +Shell three-sided pyramidal, with three annular strictures. Length of the +four joints = 1 : 2 : 9 : 3. Cephalis small, hemispherical, with two large, +prismatic, divergent horns of three times the length. The three prominent +edges of the second and third joints are finely latticed and dentated, and +at the basal end of the third joint are prolonged into three stout, free, +pointed, pyramidal, divergent wings, about as long as the horns. The fourth +joint is only as long as the second, three-sided prismatic, its wide +triangular mouth is armed with six parallel, vertical, slender teeth (two +between every three wings). Network very delicate and regular, in the first +and second joints with circular, in the third and fourth joints with small +hexagonal meshes. + +_Dimensions._--Length of the shell (with four joints) 0.3, breadth of the +third joint 0.3, of the fourth 0.2. Length of the single joints, _a_ 0.02, +_b_ 0.04, _c_ 0.18, _d_ 0.06. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + +2. _Artopilium longicorne_, n. sp. (Pl. 77, fig. 10). + +Shell subovate, with three internal annular septa. Length of the four +joints = 2 : 3 : 2 : 6. Cephalis hemispherical, with a very large +three-sided prismatic horn, nearly as long as the shell. Along the three +following joints arise three broad, triangular, latticed wings, about as +long as the shell. The fourth joint is the broadest, and twice as broad as +the constricted mouth. Pores in the two upper joints regular, circular, in +the two lower and the three wings hexagonal. + +_Dimensions._--Length of the shell (with four joints) 0.13, breadth 0.09. +Length of the single joints, _a_ 0.02, _b_ 0.03, _c_ 0.02, _d_ 0.06. + +_Habitat._--Central Pacific, Station 263, depth 2650 fathoms. + + +3. _Artopilium cyrtopterum_, n. sp. (Pl. 77, fig. 12). + +Shell subovate, with three sharp strictures. Length of the four joints = +1 : 2 : 3 : 3. Cephalis subspherical, with a stout, pyramidal horn of twice +the length. Along the second and third joints arise three broad, +triangular, latticed wings, about half as long as the shell. The third +joint is the broadest, and twice as broad as the constricted mouth. Pores +subregular, circular. + +_Dimensions._--Length of the shell (with four joints) 0.18, breadth 0.1. +Length of the single joints, _a_ 0.02, _b_ 0.04, _c_ 0.06, _d_ 0.06. + +_Habitat._--North Pacific, Station 253, depth 3125 fathoms. + + + +{1441}Subgenus 2. _Clathropyrgus_, Haeckel, 1881, Prodromus, p. 439. + +_Definition._--Shell with four or more annular strictures, and five or more +joints. + + +4. _Artopilium trifenestra_, n. sp. (Pl. 75, fig. 7). + + _Clathropyrgus trifenestra_, Haeckel, 1881, Prodromus et Atlas (_loc. + cit._). + +Shell tower-shaped, nearly cylindrical, with nine deep strictures. The ten +joints are of different lengths and breadths. The third and fourth joints +are the longest, twice as long as the first, fifth, sixth, eighth, and +ninth joints. The third, seventh, and tenth joints are the broadest, and +nearly twice as broad as the second and ninth joints. The mouth of the last +joint is dilated. The second joint bears three divergent ribs, and the +third joint (as prolongations of these) three broad, triangular, +lattice-wings, and between the latter three large, ovate openings or +windows, recalling those in _Clathrocanium_ (Pl. 64). Cephalis +subspherical, with a pyramidal horn of twice the length. Pores subregular, +circular, hexagonally framed. + +_Dimensions._--Length of the shell (with ten joints) 0.28, of the first and +ninth joints 0.02, of the third and fourth joints 0.04; breadth of the +third and seventh joints 0.08, of the second and ninth joints 0.04. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +5. _Artopilium trigonopterum_, n. sp. + +Shell in the upper half campanulate-conical, in the lower half cylindrical, +with seven internal septa. The four middle joints are equal in length, each +about twice as long as each of the two first and of the two last joints. +Cephalis hemispherical, with a conical horn of the same length. Along the +first three joints arise three broad, triangular, lattice-wings. Pores +small, regular, hexagonal, in the wings and the two first joints circular. +The five lower joints are of equal breadth. + +_Dimensions._--Length of the shell (with eight joints) 0.2, breadth 0.1. +Length of the four middle joints, each about 0.034, of the two first and +the two last, each 0.017. + +_Habitat._--South Pacific, Station 300, depth 1375 fathoms. + + +6. _Artopilium cornutella_, n. sp. + +Shell slenderly conical, without external strictures, but with twelve to +fifteen internal annular septa. All thirteen to sixteen joints are nearly +equal or slightly different in length, but increase gradually in breadth. +Along the whole shell arise three narrow, divergent lattice-wings, +increasing in height towards the wide open mouth. Pores subregular, square, +in three to four transverse rows on each joint, half as large in the three +wings as in the joints. Cephalis small, subspherical, with a conical horn +of twice the length. (In the specimen described the axis of the slender +cone was straight, in another incomplete specimen curved; this may perhaps +be a separate species, _Artopilium curvatum_.) + +{1442}_Dimensions._--Length of the shell (with sixteen joints) 0.3, basal +breadth 0.12. Length of each single joint (on an average), 0.02. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +7. _Artopilium stichopterygium_, n. sp. (Pl. 75, fig. 8). + + _Stichopterygium tanypterum_, Haeckel, 1881, Prodromus, p. 439, et Atlas. + +Shell slenderly ovate, subconical, with five deep strictures. The four +lower joints are nearly equal in length, each about twice as long as each +of the first two joints. The fourth and fifth joints are the broadest. +Along the whole shell arise three broad, triangular wings, which envelop +the long, slender, pyramidal horn of the cephalis. In the delicate and +loose lattice-work of each wing is a longitudinal series of six large, +ovate apertures, one on each joint. The small pores of the shell are +irregular, polygonal, or roundish. + +_Dimensions._--Length of the shell (with six joints) 0.17, breadth 0.08. +Length of each of the four lower joints 0.03, of each of the two upper +joints 0.015. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +8. _Artopilium anomalum_, Haeckel. + + _Eucyrtidium anomalum_, Haeckel, 1862, Monogr. d. Radiol., p. 323, Taf. + vii. figs. 11-13. + + _Lithocampe anomala_, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 839. + + _Stichopterygium anomalum_, Haeckel, 1881, Prodromus, p. 439. + +Shell five-jointed, with four internal septa, of a peculiar, irregular, and +abnormal form. Cephalis small, hemispherical, with an oblique, curved horn. +Thorax inflated, campanulate, with three large, latticed, and carinated +protuberances. The third joint (the first abdominal joint) nearly as large +as the thorax, two to three times as long as the two last joints, the septa +of which are connected in a peculiar manner by a common nodal point on one +side. Pores subregular, circular. (Compare the detailed description of this +remarkable species--perhaps the type of a peculiar genus, +_Stichopterygium_--in my Monograph, _loc. cit._) + +_Dimensions._--Length of the shell (with five joints) 0.15, breadth 0.1. + +_Habitat._--Mediterranean (Messina), surface. + + + +Genus 628. _Pteropilium_,[245] n. gen. + +_Definition._--#Stichopilida# (vel Stichocyrtida triradiata aperta) with +three latticed external ribs or wings, without terminal feet. No horn upon +the cephalis. + +The genus _Pteropilium_ (confounded by Ehrenberg with _Pterocanium_) +differs from this three-jointed form by addition of new terminal joints. +The shell-form is in general the same as in the preceding species, from +which it may be derived by phylogenetic loss of the cephalic horn. + + +{1443}1. _Pteropilium sphinx_, Haeckel. + + _Pterocanium sphinx_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 255, Taf. xvii. fig. 5. + +Shell slenderly conical, with three slight strictures. Each of the two last +joints as long as the two first joints together. Cephalis hemispherical. +Third joint with three prominent, divergent ribs, which are prolonged along +the fourth joint into three latticed, triangular wings, ending in a free, +strong, conical spine. Pores subregular, circular, twice as broad in the +fourth joint as in the third, and three times as broad as in the second +joint. + +_Dimensions._--Length of the shell (with four joints) 0.15, of the single +joints, _a_ 0.02, _b_ 0.03, _c_ 0.05, _d_ 0.05; breadth of the third joint +0.09, of the fourth joint 0.06. + +_Habitat._--Fossil in Barbados. + + +2. _Pteropilium bombus_, Haeckel. + + _Pterocanium bombus_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 82, Taf. xvii. fig. 4. + +Shell broadly conical, with three deep strictures. Length and breadth of +the four joints, gradually increasing giving the proportion 2 : 4 : 5 : 6. +Cephalis hemispherical, second joint with three prominent ribs, which are +prolonged along the third and fourth joints into three slender, triangular +pointed wings, with few pores at the base. Pores of the shell subregular, +circular. + +_Dimensions._--Length of the shell (with four joints) 0.17, of the single +joints, _a_ 0.02, _b_ 0.04, _c_ 0.05, _d_ 0.06; basal breadth 0.11. + +_Habitat._--Fossil in Barbados. + + +3. _Pteropilium pyramis_, n. sp. + +Shell three-sided, pyramidal, with five deep strictures. Length and breadth +of the six joints gradually increasing towards the wide mouth. Cephalis +subconical. Along the four first joints arise three slender, divergent +ribs, which at the fifth joint become three free, triangular, latticed +wings, with long, descending, terminal spines. The sixth joint is free, +without wings. Pores irregular, roundish. + +_Dimensions._--Length of the shell (with six joints) 0.2, basal breadth +0.2. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + + +Genus 629. _Stichocampe_,[246] Haeckel, 1881, Prodromus, p. 439. + +_Definition._--#Stichopilida# (vel Stichocyrtida triradiata aperta) with +three solid lateral ribs or wings, which are prolonged into three solid +terminal feet. Cephalis with a horn. + +{1444}The genus _Stichocampe_, together with the three following genera, +represent a peculiar small group among the Stichocyrtida, differing from +all other members of this family in the possession of three free terminal +feet around the open mouth. In the two genera, _Stichocampe_ and +_Stichopterium_, these three feet are the terminal prolongations of three +lateral ribs or crests, while in the two genera developed later, +_Podocampe_ and _Stichopodium_, the three original ribs are lost, and only +the three free feet remain. _Stichocampe_ (the most primitive of these four +genera) may be derived from _Theopodium_ by addition of new joints. + + +1. _Stichocampe divergens_, n. sp. + +Shell spiny, broadly pyramidal, with six deep strictures. Seven joints +gradually increasing in breadth and length, the seventh twice as broad as +the fourth. Pores subregular, circular, hexagonally framed. The prominent +edges of the pyramis are prolonged over the wide mouth into three slender, +straight, divergent feet, half as long as the shell. + +_Dimensions._--Length of the shell (with seven joints) 0.3, of the last +joint 0.06, of the fourth 0.03; breadth 0.25. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +2. _Stichocampe convergens_, n. sp. + +Shell smooth, slenderly pyramidal, with eight distinct strictures. All nine +joints nearly equal in length. Pores regular, circular, forming three or +four transverse rows in each joint. The smooth edges of the pyramis are +prolonged over the wide mouth into three slender, slightly curved, and +convergent feet, twice as long as one joint. + +_Dimensions._--Length of the shell (with nine joints) 0.25, of each joint, +about 0.035; breadth 0.11. + +_Habitat._--Central Pacific, Station 273, depth 2350 fathoms. + + + +Genus 630. _Stichopterium_,[247] Haeckel, 1881, Prodromus, p. 439. + +_Definition._--#Stichopilida# (vel Stichocyrtida triradiata aperta), with +three lateral ribs or wings, which are prolonged into three latticed, +terminal feet. Cephalis with a horn. + +The genus _Stichopterium_ has in general the same shell-formation as the +nearly allied _Stichocampe_, but differs from this ancestral form in the +fenestration of the three terminal feet. It corresponds, therefore, to +_Pterocanium_ among the Tricyrtida. + + +{1445}1. _Stichopterium pterocanium_, n. sp. + +Shell campanulate, with three distinct strictures. Length of the four +joints = 2 : 3 : 4 : 3. Cephalis subspherical, with a conical horn of twice +the length. Pores regular, hexagonal, with thin bars. From the collar +stricture arise three divergent ribs, which in the fourth joint become +latticed and prolonged over its mouth into three slender, pyramidal, +latticed, divergent feet, nearly as long as the shell. (Similar to +_Pterocanium bicorne_, Pl. 73, fig. 5, but with four distinct strictures.) + +_Dimensions._--Length of the shell (with four joints) 0.12, breadth 0.1. +Length of the single joints, _a_ 0.02, _b_ 0.03, _c_ 0.04, _d_ 0.03. + +_Habitat._--South Pacific (off Patagonia), Station 304, surface. + + +2. _Stichopterium virgineum_, n. sp. + +Shell three-sided, pyramidal, with four sharp strictures. Length of the +five joints = 1 : 4 : 3 : 2 : 1. Cephalis hemispherical, with a pyramidal +horn three times the length. Pores subregular, circular, in the second +campanulate joint twice or three times as broad as in the four other +joints. From the base of the cephalic horn arise three divergent ribs, +which descend over the whole shell, and in the fourth joint become latticed +and prolonged over the wide mouth of the fifth joint into three latticed, +pyramidal feet, as long as the second joint. (Similar in general form to +_Pterocanium virgineum_, Pl. 73, fig. 6.) + +_Dimensions._--Length of the shell (with five joints) 0.22, breadth 0.16. +Length of the single joints, _a_ 0.02, _b_ 0.08, _c_ 0.06, _d_ 0.04, _e_ +0.02. + +_Habitat._--Central Pacific, Station 281, surface. + + +3. _Stichopterium dictyopodium_, n. sp. + +Shell subovate, with five internal annular septa. The third and the fourth +joints are about twice as long as the two first and the two last joints. +The fifth joint is the broadest. Pores small and numerous, regular, +circular. The three first joints are without ribs. From the third stricture +arise three divergent, triangular, latticed wings, which descend along the +three last joints, and are prolonged over the wide mouth as three slender, +fenestrated, divergent feet, two-thirds as long as the shell. + +_Dimensions._--Length of the shell (with six joints) 0.18, breadth 0.12. +Length of the two middle joints 0.04, of the four others 0.02 to 0.03. + +_Habitat._--South Pacific, Station 288, surface. + + + +Genus 631. _Podocampe_,[248] Haeckel, 1881, Prodromus, p. 439. + +_Definition._--#Stichopilida# (vel Stichocyrtida triradiata aperta), +without lateral ribs or wings, but with three free, solid, terminal feet. +Cephalis with a horn. + +{1446}The genus _Podocampe_ is next allied to _Stichocampe_, and has also +three solid, free feet around the mouth, but it has lost the three lateral +ribs of the latter. It corresponds to _Podocyrtis_ among the Tricyrtida, +and may be derived from this by addition of new terminal joints. + + +1. _Podocampe tripodiscus_, n. sp. + +Shell ovate, with three annular septa. The fourth joint is the broadest, +and as long as the three other joints together. Cephalis hemispherical, +with a pyramidal horn of twice the length. Mouth constricted, with three +convergent, curved, triangular feet, half as long as the last joint. Pores +subregular, circular. (Similar to _Podocyrtis pedicellaria_, Pl. 72, fig. +8, but larger, with more slender feet, and four joints instead of three.) + +_Dimensions._--Length of the shell (with four joints) 0.2, of the last +joint 0.1; breadth 0.12. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +2. _Podocampe trictenota_, n. sp. (Pl. 97, fig. 15). + +Shell slenderly ovate, nearly spindle-shaped, with three annular septa. The +third joint is the broadest, somewhat longer than the second and third +joints, and three times as long as the hemispherical cephalis, which bears +a strong pyramidal horn of twice the length. Along the two first joints +arise three divergent, dentate crests, each with four to six strong +pyramidal teeth. Mouth strongly constricted, only as broad as the cephalis, +with three conical, vertical, parallel feet, as long as the cephalis. Pores +regular, circular, hexagonally framed. + +_Dimensions._--Length of the shell (with four joints) 0.14, of the third +joint 0.06, of the last 0.04; breadth 0.08. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +3. _Podocampe conica_, n. sp. + +Shell conical, with five distinct strictures. Six joints gradually +increasing in length and breadth. The sixth joint is the broadest, and +twice as long as the fifth joint, three times as long as the fourth. +Cephalis conical, with a stout, conical horn of the same length. Mouth +little constricted, with three divergent, conical feet, half as long as the +shell. Pores subregular, circular. (Similar to _Podocyrtis lithoconus_, Pl. +72, fig. 3, but with six joints instead of three, and with divergent, +slender feet.) + +_Dimensions._--Length of the shell (with six joints) 0.18, of the last +joint 0.06; breadth 0.12. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +4. _Podocampe cornuta_, n. sp. + +Shell slenderly conical, with seven distinct strictures. Eight joints of +nearly equal length, gradually increasing in breadth. Along the three last +joints arise three prominent crests, which are {1447}prolonged over the +wide mouth into three divergent, conical feet, half as long as the shell. +Cephalis hemispherical, with a conical, slender, curved horn, three times +the length. Pores subregular, hexagonal. + +_Dimensions._--Length of the shell (with eight joints) 0.16, of each single +joint (on an average) 0.02; basal breadth 0.07. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + + +Genus 632. _Stichopodium_,[249] Haeckel, 1881, Prodromus, p. 439. + +_Definition._--#Stichopilida# (vel Stichocyrtida triradiata aperta) without +lateral ribs or wings, but with three free latticed terminal feet. Cephalis +with a horn. + +The genus _Stichopodium_ differs from the preceding genus _Podocampe_ in +the fenestration of the three free terminal feet. It agrees in this +character with the genus _Stichopterium_, and may be derived either from +this by loss of the lateral ribs, or from the three-jointed _Pterocanium_ +by addition of new shell-joints. + + +1. _Stichopodium dictyopodium_, n. sp. (Pl. 75, fig. 6). + +Shell subcylindrical, in the upper third conical, with six or seven +internal annular septa. All seven or eight joints are about equal in +length, except the small hemispherical cephalis, which is scarcely half as +long, and bears an oblique, conical horn of the same length. Pores small +and numerous, regular, circular, quincuncial. The last joint with wide open +mouth, and a peristome of three large, triangular, latticed, shovel-shaped, +vertical feet. + +_Dimensions._--Length of the shell (with seven joints) 0.2, breadth 0.11. +Length of each single joint about 0.03, of the feet 0.03. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + + +Subfamily 2. STICHOPERIDA, Haeckel, Prodromus, p. 439. + +_Definition._--#Podocampida# with the terminal mouth of the shell +fenestrated (vel Stichocyrtida triradiata clausa). + + + +Genus 633. _Stichopera_,[250] Haeckel, 1881, Prodromus, p. 439. + +_Definition._--#Stichoperida# (vel Stichocyrtida triradiata clausa) with +three solid lateral ribs, or three longitudinal combs of spines. Cephalis +with a horn. + +{1448}The genus _Stichopera_, and the two following genera, represent the +small subfamily of Stichoperida, or those triradiate Stichocyrtida in which +the terminal mouth is closed by lattice-work. In _Stichopera_ the three +radial appendages are either solid lateral ribs or longitudinal combs of +spines; the closed basal part of the shell is rounded, not pointed. It may +be derived either from _Stichopilium_ by closure of the mouth, or from +_Lithornithium_ by increase of the number of the joints. + + + +Subgenus 1. _Stichoperina_, Haeckel. + +_Definition._--Shell with three solid radial ribs, or longitudinal dentate +crests. + + +1. _Stichopera ovata_, n. sp. + +Shell ovate, with three distinct strictures. Length of the four joints = +2 : 3 : 4 : 6. The fourth joint is the broadest, and twice as long as the +second, with hemispherical basal pole. Cephalis hemispherical, with a +conical horn of twice the length. Along the second and third joints descend +three prominent divergent ribs, which disappear in the middle zone of the +fourth joint. Pores regular, circular. + +_Dimensions._--Length of the shell (with four joints) 0.15, breadth 0.1. +Length of the single joint, _a_ 0.02, _b_ 0.03, _c_ 0.04, _d_ 0.06. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +2. _Stichopera lagena_, n. sp. + +Shell bottle-shaped, with six sharp strictures; the upper half is slender, +conical, and composed of six joints of nearly equal length, the lower half +is formed only by the last subspherical joint. Cephalis subspherical, with +a pyramidal horn of the same length. From its base arise three divergent +ribs, which attain the greatest height in the fourth joint, and disappear +in the sixth joint. (Similar to _Stichophaena ritteriana_, Pl. 75, fig. 12, +but only with three ribs and seven joints.) Pores regular, hexagonal. + +_Dimensions._--Length of the shell (with seven joints) 0.25. Length of each +joint 0.02 to 0.025, of the last joint 0.12; breadth 0.14. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +3. _Stichopera serrata_, n. sp. + +Shell bottle-shaped, with eight deep strictures. The first eight joints are +little different in length, and form together a slender cone, while the +last joint is four times as long (half as long as this cone), and +subspherical. Cephalis conical, with a slender, prismatic horn of three +times the length. Along the whole shell arise three divergent, serrate +ribs, which disappear towards the hemispherical, basal pole. Pores +subregular, hexagonal. + +{1449}_Dimensions._--Length of the shell (with nine joints) 0.21, breadth +0.08; length of each joint 0.016 to 0.019, of the last joint 0.07. + +_Habitat._--Western Tropical Pacific, Station 224, depth 1850 fathoms. + + + +Subgenus 2. _Sticholagena_, Haeckel. + +_Definition._--Shell with three radial combs or longitudinal rows of +isolated spines (instead of the three radial ribs). + + +4. _Stichopera pectinata_, n. sp. (Pl. 75, fig. 11). + +Shell club-shaped, with nine sharp strictures. The nine upper joints +increase gradually in length and breadth, and are together three times as +long as the inflated, inversely campanulate and rounded last joint. Each +joint (excepting the first and the last) bears three thin, bristle-shaped +spines, which are directed obliquely upwards. Cephalis subspherical, with a +slender, conical horn of twice the length. Pores subregular, in the upper +half circular, in the lower hexagonal. + +_Dimensions._--Length of the shell (with ten joints) 0.22, breadth 0.09; +length of the eighth and ninth joints 0.02, of the last joint 0.075. + +_Habitat._--North Pacific, Station 241, depth 2300 fathoms. + + +5. _Stichopera clavata_, n. sp. + +Shell club-shaped, with eight sharp strictures, very similar in form and +structure to that of the preceding species, but differing from it in the +club-like form of the inflated last joint, which is nearly half as long as +the shell; its lower half is broader than the upper (the reverse being the +case in the preceding species). The lateral spines of the three combs are +not directed upwards, but downwards. Cephalis with a curved, conical horn +of the same length. + +_Dimensions._--Length of the shell (with nine joints) 0.2, breadth 0.08; +length of the eighth joint 0.02, of the last joint 0.09. + +_Habitat._--South Pacific, Station 298, depth 2225 fathoms. + + +6. _Stichopera verticillata_, n. sp. + +Shell club-shaped, with ten sharp strictures, similar in form and structure +to that of the two preceding species, but differing from them in the ovate +form of the slender last joint, which is one-third as long as the whole +shell, and five times as long as the preceding joint. The lateral spines of +the three combs are directed nearly horizontally, and are much more +numerous, each joint (excepting the first and last) bears six to twelve +spines (two, three, or four in each radius). They form together about +thirty horizontal verticils, each with three spines. Cephalis with a +curved, conical horn of three times the length. + +{1450}_Dimensions._--Length of the shell (with eleven joints) 0.28, breadth +0.09; length of the tenth joint 0.02, of the last joint 0.1. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +Genus 634. _Cyrtopera_,[251] Haeckel, 1881, Prodromus, p. 439. + +_Definition._--#Stichoperida# (vel Stichocyrtida triradiata clausa) with +three latticed lateral wings, or three longitudinal rows of lattice wings. +Cephalis with a horn. + +The genus _Cyrtopera_ differs from the preceding _Stichopera_ in the +fenestration of the three lateral wings, and bears therefore to it the same +relation that _Sethornithium_ exhibits to _Lithornithium_ among the +Tricyrtida. + + + +Subgenus 1. _Artopera_, Haeckel, 1881, Prodromus, p. 438. + +_Definition._--Shell with three annular strictures and four joints. + + +1. _Cyrtopera thoracoptera_, n. sp. (Pl. 75, fig. 3). + + _Artopera thoracoptera_, Haeckel, 1881, Prodromus et Atlas (_loc. cit._). + +Shell inflated, with three very deep strictures. Length of the four joints += 2 : 7 : 8 : 6. Cephalis hemispherical, with a slender, prismatic horn, +half as long as the shell. Thorax subspherical, in its middle third with +three latticed, triangular wings of half the length. Abdomen with inflated +third, and inversely hemispherical fourth joint; the third is the broadest. +Pores subregular, hexagonal, with thin bars. + +_Dimensions._--Length of the shell (with four joints) 0.23. Breadth of the +third (broadest) joint 0.13. Length of the single joints, _a_ 0.02, _b_ +0.07, _c_ 0.08, _d_ 0.06. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +2. _Cyrtopera ornithoptera_, n. sp. + +Shell broadly ovate, with three slight strictures. Length of the four +joints = 1 : 2 : 3 : 4. Cephalis hemispherical, with a slender, pyramidal +horn of three times the length. Along the second and third joints arise +with broad base three latticed, triangular wings, nearly as long as the +whole shell. Abdomen inflated. The fourth joint is the broadest and +longest, with hemispherical basal pole. Pores subregular, hexagonal. +(Similar to _Artopilium longicorne_, Pl. 77, fig. 10, but with more closely +reticulated network, and perfectly closed mouth.) + +_Dimensions._--Length of the shell (with four joints) 0.2. Breadth of the +fourth (broadest) joint 0.14. Length of the single joints, _a_ 0.02, _b_ +0.04, _c_ 0.06, _d_ 0.08. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + +{1451}3. _Cyrtopera gasteroptera_, n. sp. + +Shell slenderly ovate, with three distinct strictures. Length of the four +joints = 2 : 6 : 7 : 6. Cephalis subspherical, with a stout pyramidal horn +of the same length. The three following joints have nearly equal length; +the third is the broadest. The thorax exhibits three divergent solid ribs; +as prolongations of these, three descending latticed wings, of about the +same length, arise from the third joint, with broad triangular base. The +fourth joint is inversely conical, blunt. Pores irregular, roundish. +(Similar to _Hexalatractus fusiformis_, Pl. 68, fig. 13, but with three +wings and four joints.) + +_Dimensions._--Length of the shell (with four joints) 0.21. Breadth of the +third (broadest) joint 0.11. Length of the single joints, _a_ 0.02, _b_ +0.06, _c_ 0.07, _d_ 0.06. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + + +Subgenus 2. _Cyrtolagena_, Haeckel, 1879, Atlas (Pl. 75). + +_Definition._--Shell with four or more annular strictures, and five or more +joints. + + +4. _Cyrtopera laguncula_, n. sp. (Pl. 75, fig. 10). + + _Cyrtolagena laguncula_, Haeckel, 1879, Manuscript et Atlas (_loc. + cit._). + +Shell bottle-shaped, with seven sharp strictures; the upper part is +slender, conical, composed of seven joints of nearly equal length; the +lower part is only formed by the spherical last joint. Cephalis +subspherical, with a slender curved horn at three times the length. Along +the whole shell arise three longitudinal combs or rows of ascending spines +(three on each joint, fifteen on the last). These are connected by three +divergent longitudinal rods, so that three elegant fenestrated ribs are +formed (each rib with one series of large square meshes). Pores in the +seven upper joints regular, circular, in the last polygonal, irregular and +larger. + +_Dimensions._--Length of the shell (with eight joints) 0.17, of the last +joint 0.08; breadth 0.08. + +_Habitat._--South Pacific, Station 298, depth 2225 fathoms. + + +5. _Cyrtopera lagenella_, n. sp. + +Shell bottle-shaped, with twelve sharp strictures, very similar in form and +structure to the preceding species; but instead of the three simple +fenestrated ribs there arise here, along the shell, three series of short, +triangular, latticed wings. The four first and the last joints are without +wings. The hemispherical cephalis bears a curved conical horn, as long as +the subspherical last joint. The twelve joints of the upper conical part +are nearly equal in length, with regular, small, hexagonal pores. The last +inflated joint is one-third as long as the shell, and has larger, +irregular, polygonal pores. + +_Dimensions._--Length of the shell (with thirteen joints) 0.25, of the last +joint 0.08; breadth 0.1. + +_Habitat._--South Pacific, Station 300, depth 1375 fathoms. + + + +{1452}Genus 635. _Artopera_,[252] Haeckel, 1881, Prodromus, p. 438. + +_Definition._--#Stichoperida# with three solid lateral ribs or wings, and +with a vertical basal spine on the end of the pointed last joint. Cephalis +with a horn. + +The genus _Artopera_ differs from its ancestral genus, _Stichopera_, in the +development of a vertical terminal spine on the end of the last joint, and +bears therefore to it the same relation that _Rhopalatractus_ exhibits to +_Rhopalocanium_ among the Tricyrtida. + + +1. _Artopera loxia_, Haeckel. + + _Lithornithium loxia_, Ehrenberg, 1854, Mikrogeol., Taf. xxxvi. fig. 8; + Abhandl. d. k. Akad. d. Wiss. Berlin, 1875, p. 78, Taf. iv. fig. 8. + +Shell spindle-shaped, with three deep strictures. Length of the four joints += 2 : 5 : 5 : 4. Cephalis subspherical, hyaline, without pores, with a +thick conical horn of the same length. From the two following joints, which +are nearly equal in size and of campanulate form, arise, with broad base, +three divergent, slender, triangular wings. The fourth joint is smaller, +inversely conical, and bears on the basal pole a strong, three-sided +pyramidal, vertical spine, half as long as the shell. Pores subregular, +circular. + +_Dimensions._--Length of the shell (with four joints) 0.18, breadth 0.07. +Length of the single joints, _a_ 0.02, _b_ 0.055, _c_ 0.055, _d_ 0.05. + +_Habitat._--Fossil in Barbados. + + +2. _Artopera motacilla_, n. sp. + +Shell spindle-shaped, with three distinct strictures. Length of the four +joints = 1 : 2 : 3 : 2. Cephalis subspherical, with a conical horn of twice +the length. From the second joint arise three longitudinal, smooth, +divergent ribs, which are prolonged over the third joint, and terminate at +the third stricture in three short, conical teeth. The fourth is inversely +conical, and bears on the basal pole a strong, vertical, cylindrical spine, +nearly half as long as the shell. Pores subregular, circular, hexagonally +framed. (Similar to _Rhopalatractus pentacanthus_, Pl. 68, fig. 11, but +differing in the presence of three sharp strictures, and a large, conical, +basal joint). + +_Dimensions._--Length of the shell (with four joints) 0.18. Breadth of +third (broadest) joint 0.09. Length of the single joint, _a_ 0.02, _b_ +0.04, _c_ 0.06, _d_ 0.04. + +_Habitat._--Western Tropical Pacific (Philippine Sea), Station 198, depth +2150 fathoms. + + +3. _Artopera fusiformis_, n. sp. + +Shell spindle-shaped, with three distinct strictures. Length of the four +joints = 2 : 3 : 5 : 5. Cephalis conical, with a strong, conical horn of +the same length. Along the three first joints arise {1453}three divergent, +irregularly dentate ribs, which at the second joint bear stronger, +pyramidal teeth, also at the third stricture a strong, terminal tooth. +Fourth joint without ribs, inversely conical, with a strong, conical, +terminal spine of half the length on the basal pole. Pores subregular, +circular, double-edged. + +_Dimensions._--Length of the shell (with four joints) 0.15. Breadth of the +third (broadest) joint 0.08. Length of the single joint, _a_ 0.02, _b_ +0.03, _c_ 0.05, _d_ 0.05. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + + +Family LXIX. #PHORMOCAMPIDA#, n. fam. + + _Artophormida et Artophaenida, Stichophormida et Stichophaenida_, + Haeckel, 1881, Prodromus, pp. 438, 439. + +_Definition._--#Stichocyrtida# multiradiata. (#Cyrtoidea# with an annulated +shell, divided by three or more transverse constrictions into four or more +annular joints, with numerous, four to nine or more, radial apophyses.) + +The family #Phormocampida# comprises those #Cyrtoidea# in which the +lattice-shell is composed of numerous (four to eight or more) annular +joints, and bears numerous (four to eight or more) radial apophyses. We +divide it into two subfamilies, differing in the shape of the terminal +mouth. This is a simple wide opening in the Stichophormida (and the united +Artophormida), closed by a lattice-plate in the Stichophaenida (and the +united Artophaenida). The phylogenetic origin of the Phormocampida may be +found in the Phormocyrtida. + +Three fossil forms only of Phormocampida were hitherto known, two of which +were described by Stoehr as _Eucyrtidium acutatum_ and _Lithocampe +fimbriata_, the third by Ehrenberg as _Eucyrtidium barbadense_; the latter +belongs to _Artophormis_, the two former to _Cyrtophormis_. All the other +Phormocampida here described, forming together thirty-one species, are new; +twenty-two of them belong to the Stichophormida, and nine to the +Stichophaenida. The latter are disposed in two, the former in four genera. + +The number of the radial apophyses is sometimes six or nine, sometimes +twelve or more, usually a multiple of three. They are either lateral ribs +or wings (Pl. 75, figs. 2, 5, 12), or terminal feet (Pl. 77, figs. 13 to +18). Usually they are solid, not latticed, and not strongly developed. The +majority of Phormocampida have probably been derived from Phormocyrtida by +growth of the abdomen, which becomes annulated by transverse constrictions. +Some forms, however, may be derived from similar Podocampida, by +interpolation of three to six or more secondary apophyses between the three +primary or perradial apophyses. + +{1454}_Synopsis of the Genera of Phormocampida._ + + ------------------------------------------------------------------------- + I. Subfamily Stichophormida. + Mouth of the terminal joint open, simple. + ------------------------------------------------------------------------- + { Lateral ribs prolonged + Shell conical or { into the terminal feet, 636. _Stichophormis_. + pyramidal. Mouth wide { + open, not constricted. { No lateral ribs. Feet + { free, terminal, 637. _Phormocampe_. + + { + { Lateral ribs prolonged + Shell ovate or spindle- { into the terminal feet, 638. _Artophormis_. + shaped. Mouth more { + or less constricted. { No lateral ribs. Feet + { free, terminal, 639. _Cyrtophormis_. + ------------------------------------------------------------------------- + II. Subfamily Stichophaenida. + Mouth of the terminal joint closed by a lattice-plate. + ------------------------------------------------------------------------- + Six radial ribs or wings, 640. _Artophaena_. + + Nine radial ribs or wings, 641. _Stichophaena_. + + + +Subfamily 1. STICHOPHORMIDA, Haeckel, 1881, Prodromus, p. 439. + +_Definition._--#Phormocampida# with the terminal mouth of the shell open +(vel Stichocyrtida multiradiata aperta). + + + +Genus 636. _Stichophormis_,[253] Haeckel, 1881, Prodromus, p. 439. + +_Definition._--#Stichophormida# (vel Stichocyrtida multiradiata aperta) +with conical or pyramidal shell, bearing in its wall numerous lateral ribs, +which are prolonged into terminal feet. Mouth not constricted. + +The genus _Stichophormis_ and the three following genera represent together +the subfamily of Stichophormida, or of those multiradiate Stichocyrtida in +which the mouth remains open; they may be derived therefore either from the +Theophormida by increasing the number of the shell-joints, or from the +Stichopilida by the interpolation of new radial ribs between the three +primary ribs. _Stichophormis_ may have been derived in the former way from +_Theophormis_. + + + +Subgenus 1. _Stichophormium_, Haeckel. + +_Definition._--Shell with six prominent longitudinal ribs, which are +prolonged into six (sometimes five or seven) divergent free feet over the +mouth. + + +1. _Stichophormis pyramidalis_, n. sp. + +Shell slenderly pyramidal, with three annular septa, and six prominent +radial ribs, which arise from the collar-septum, and are prolonged on the +mouth into six free, divergent, pyramidal feet, {1455}about as long as the +shell. Length of the four joints = 2 : 3 : 5 : 8. Cephalis subspherical, +with a stout, pyramidal horn of twice the length. Pores regular, circular. + +_Dimensions._--Length of the shell (with four joints) 0.18, basal breadth +0.08. Length of the single joints, _a_ 0.02, _b_ 0.03, _c_ 0.05, _d_ 0.08. + +_Habitat._--Central Pacific, Station 273, depth 2350 fathoms. + + +2. _Stichophormis lucerna_, n. sp. + +Shell slenderly pyramidal, with three annular septa and six prominent +radial ribs, which arise from the second stricture, and are prolonged over +the mouth into six free, divergent, cylindrical feet, half as long as the +shell. Length of the four joints = 1 : 2 : 3 : 15. Cephalis hemispherical, +with a prismatic horn of the same length. Pores in the first and second +joints very small and scarce, in the third campanulate joint circular, +hexagonally framed, in the colossal fourth joint very large, polygonal +(each about as large as the third joint). + +_Dimensions._--Length of the shell (with four joints) 0.4, basal breadth +0.2. Length of the single joints _a_ 0.02, _b_ 0.04, _c_ 0.06, _d_ 0.3. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +3. _Stichophormis cornutella_, n. sp. (Pl. 75, fig. 9). + +Shell slenderly conical, with nine annular strictures and six longitudinal +divergent ribs, which arise in the middle of the shell (from the sixth or +seventh stricture), and are prolonged over the wide mouth into six slender +bristle-shaped feet, about half as long as the shell. The bases of the feet +are connected by arcades of lattice-work. All ten joints have nearly the +same length and regular hexagonal pores (in the first and second joints +circular). Cephalis hemispherical, with a very large curved horn, nearly +half as long as the shell, and on one side decurrent to the fourth or fifth +joint. + +_Dimensions._--Length of the shell (with ten joints) 0.16, of each single +joint about 0.016; basal breadth 0.07. + +_Habitat._--North Pacific, Station 253, depth 3125 fathoms. + + + +Subgenus 2. _Stichophormiscus_, Haeckel. + +_Definition._--Shell with nine prominent radial ribs, which are prolonged +over the mouth into nine (sometimes eight or ten) divergent free feet. + + +4. _Stichophormis novena_, n. sp. (Pl. 79, fig. 9). + +Shell slenderly conical, very similar to the preceding, but with eleven +annular strictures and nine divergent ribs, which arise from the tenth or +eleventh stricture, and are prolonged over the wide mouth into nine +bristle-shaped feet, half as long as the shell. The length of the twelve +joints increases gradually; the tenth is twice as long as the sixth. Pores +regular, circular. Cephalis {1456}hemispherical, with a curved conical horn +of twice the length. (In the somewhat mutilated specimen figured, the horn +and the nine feet were broken off, but were well preserved in another +specimen, found afterwards.) + +_Dimensions._--Length of the shell (with twelve joints) 0.22, eighth joint +0.02, fourth joint 0.01; basal breadth 0.12. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +5. _Stichophormis radiata_, n. sp. + +Shell slender, conical, with fourteen annular strictures, and nine radial +ribs; three primary ribs arise from the third stricture, the other six +(secondary) ribs from the ninth stricture; all are prolonged over the mouth +into nine slender bristle-shaped feet, about twice as long as one joint. +All joints have nearly the same length. Cephalis subspherical, with a +straight, conical horn three times the length. Pores regular, hexagonal. + +_Dimensions._--Length of the shell (with fifteen joints) 0.24, of each +joint, about 0.016; basal breadth 0.12. + +_Habitat._--South Pacific, Station 300, depth 1375 fathoms. + + + +Genus 637. _Phormocampe_,[254] n. gen. + +_Definition._--#Stichophormida# (vel Stichocyrtida multiradiata aperta), +with conical or pyramidal shell, without lateral ribs. Mouth dilated, with +a corona of terminal feet. + +The genus _Phormocampe_ may be derived from the preceding _Stichophormis_ +by loss of the lateral ribs, whilst the terminal feet remain. It bears +therefore to the latter the same relation that _Calocyclas_ exhibits to +_Theophormis_ among the Tricyrtida. + + + +Subgenus 1. _Anthocorys_, Haeckel, 1881, Prodromus, p. 437. + +_Definition._--Shell with three transverse strictures or annular septa, and +with four distinct joints. + + +1. _Phormocampe campanula_, n. sp. (Pl. 77, fig. 13). + + _Anthocorys campanula_, Haeckel, 1881, Prodromus et Atlas (_loc. cit._). + +Shell campanulate, with three internal, annular septa. Length of the four +joints = 5 : 2 : 8 : 3. Cephalis three-sided, pyramidal, slender, bearing a +pyramidal horn of the same length, with three dentate edges. Thorax very +small, hemispherical. Third joint very large, campanulate. Fourth joint of +the same breadth, but only one-third as long. Pores subregular, circular. +Peristome with a coronal of twelve to fifteen conical, divergent feet, as +long as the last joint. + +{1457}_Dimensions._--Length of the shell (with four joints) 0.18, breadth +0.09. Length of the single joints, _a_ 0.05, _b_ 0.02, _c_ 0.08, _d_ 0.03. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +2. _Phormocampe lamprocyclas_, n. sp. (Pl. 77, fig. 16). + +Shell conical, with three internal annular septa. Length of the four joints += 1 : 1 : 3 : 4. Cephalis subspherical, as large as the thorax, with a +stout, pyramidal horn of three times the length, bearing at the apex a +spinulate knob. The fourth joint is the broadest, and has large, circular, +hexagonally-framed pores, two to three times as broad as the circular pores +of the three first joints. Peristome with a double coronal of short, +conical, divergent feet, nine on each coronal. + +_Dimensions._--Length of the shell (with four joints) 0.16, breadth 0.11. +Length of the single joints, _a_ 0.02, _b_ 0.02, _c_ 0.05, _d_ 0.07. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +3. _Phormocampe eucalyptra_, n. sp. (Pl. 77, fig. 14). + +Shell flatly conical, somewhat broader than long, with four internal +annular septa. The four joints increase gradually in length and breadth. +Pores subregular, hexagonal. Cephalis hemispherical, with two small, +divergent horns. Peristome with a coronal of thirty to forty short, +conical, divergent feet. + +_Dimensions._--Length of the shell 0.14, breadth 0.17. Length of the single +joints, _a_ 0.02, _b_ 0.03, _c_ 0.04, _d_ 0.05. + +_Habitat._--North Pacific, Station 241, depth 2300 fathoms. + + +4. _Phormocampe metalis_, n. sp. + +Shell spiny, with three broad internal annular septa. Three of the four +joints are nearly equal in length, each being three times as long as the +first. Cephalis subspherical, with a conical horn of twice the length. The +second and third joints are together nearly ellipsoidal, and are not +separated externally. The fourth joint is separated from them by a deep +stricture, one and a half times as broad, and flatly conical. Pores +subregular, circular, hexagonally framed. Peristome with a coronal of +twenty to thirty strong, conical, divergent feet. + +_Dimensions._--Length of the shell 0.22, basal breadth 0.16. Length of the +single joint, _a_ 0.02, _b_ 0.06, _c_ 0.06, _d_ 0.08. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + + +Subgenus 2. _Cyrtocorys_, Haeckel, 1881, Prodromus, p. 438. + +_Definition._--Shell with four or more transverse strictures, and five or +more joints. + + +{1458}5. _Phormocampe mitra_, n. sp. + +Shell broadly campanulate, conical, about as broad as long, with five +internal annular septa. Length of the six joints gradually increasing. +Cephalis flat, cap-shaped, with a short, bristle-shaped, conical horn. +Pores small and numerous, regular, hexagonal, with thin bars. Peristome +with a coronal of forty to fifty divergent, bristle-shaped feet, about as +long as the last joint. + +_Dimensions._--Length of the shell (with six joints) 0.16, of the last +joint 0.05; breadth 0.18. + +_Habitat._--North Pacific, Station 235 (off Japan), surface. + + +6. _Phormocampe conus_, n. sp. + +Shell slenderly conical, three times as long as broad, with thirteen +distinct strictures. Length of the fourteen joints nearly equal. Breadth +gradually increasing towards the mouth. Cephalis hemispherical, with a +slender, conical, curved horn of three times the length. Pores small and +numerous, regular, circular. Peristome with a coronal of twenty to thirty +slightly divergent, bristle-shaped feet, twice as long as the last joint. + +_Dimensions._--Length of the shell (with fourteen joints) 0.22, of each +joint (on an average) 0.016; basal breadth 0.08. + +_Habitat._--South Pacific, Station 297, surface. + + + +Genus 638. _Artophormis_,[255] Haeckel, 1881, Prodromus, p. 438. + +_Definition._--#Stichophormida# (vel Stichocyrtida multiradiata aperta) +with ovate or spindle-shaped shell, bearing in its wall numerous lateral +ribs, which are prolonged into terminal feet. Mouth constricted. + +The genus _Artophormis_ and the following _Cyrtophormis_ differ from the +two preceding genera in the ovate form of the shell, which tapers in +breadth towards the constricted mouth. It differs from the similar +_Alacorys_ in the greater number of the shell-joints, this being four or +more. + + +1. _Artophormis horrida_, n. sp. (Pl. 75, fig. 2). + +Shell slenderly ovate, spiny, with three deep strictures, twice as long as +broad. Length of the four joints = 2 : 5 : 6 : 7. Whole surface covered +with strong conical spines. Six prominent, longitudinal ribs, decurrent +from the cephalis to the mouth, are armed with larger spines, which in the +upper joints are directed upwards, in the lower downwards. The six ribs are +prolonged over the constricted mouth into six stout, conical feet. Cephalis +subspherical, with a conical horn and some smaller spines. Pores circular, +of very different sizes. + +{1459}_Dimensions._--Length of the shell (with four joints) 0.2, breadth +0.1. Length of the single joints, _a_ 0.02, _b_ 0.05, _c_ 0.06, _d_ 0.07. + +_Habitat._--South Pacific, Station 300, depth 1375 fathoms. + + +2. _Artophormis costata_, n. sp. + +Shell spindle-shaped, rough, with six distinct strictures, three times as +long as broad. The length of the seven joints increases gradually; the last +joint is twice as long as the fifth. Six prominent, radial ribs arise from +the third stricture, and are prolonged into six slender, convergent, +conical feet, as long as the sixth joint. Cephalis hemispherical, with a +pyramidal horn of twice the length. Pores regular, circular. + +_Dimensions._--Length of the shell (with seven joints) 0.24, breadth 0.08. +Length of the last joint 0.05. + +_Habitat._--South Pacific, Station 295, depth 1500 fathoms. + + +3. _Artophormis barbadensis_, Haeckel. + + _Calocyclas barbadensis_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 66, Taf. xviii. fig. 8. + +Shell slenderly ovate, smooth, with three sharp strictures, twice as long +as broad. Length of the four joints = 1 : 2 : 3 : 2. Nine prominent +longitudinal ribs arise from the third joint, and are prolonged into nine +slender, conical, little convergent feet. Cephalis hemispherical, with a +conical horn of the same length. Pores subregular, circular, twice as large +in the third joint as in the second; the fourth joint bears above a circle +of nine very large pores (alternate with the nine ribs), and below two or +three circles of smaller pores (eighteen to twenty-seven in the +circumference). Mouth somewhat constricted. The figure of Ehrenberg is +incomplete, the horn of the cephalis and the nine feet being broken off. + +_Dimensions._--Length of the shell (with four joints) 0.16, breadth 0.08. +Length of the single joints, _a_ 0.02, _b_ 0.04, _c_ 0.06, _d_ 0.04. + +_Habitat._--Fossil in Barbados. + + + +Genus 639. _Cyrtophormis_,[256] n. gen. + +_Definition._--#Stichophormida# (vel Stichocyrtida multiradiata aperta) +with ovate or spindle-shaped shell, without lateral ribs. Mouth +constricted, with a corona of terminal feet. + +The genus _Cyrtophormis_ may be derived from the preceding _Artophormis_ by +reduction of the lateral ribs, whilst the terminal feet (as their free +prolongations) remain, and form a corona around the mouth. Sometimes also +each constriction bears {1460}a corona of spines. It corresponds to +_Calocyclas_ among the Tricyrtida and _Anthocyrtis_ among the Dicyrtida. + + + +Subgenus 1. _Cyrtophormium_, Haeckel. + +_Definition._--Shell with six (sometimes five or seven) feet on the +peristome (three perradial alternate with three interradial). + + +1. _Cyrtophormis armata_, n. sp. (Pl. 78, fig. 17). + +Shell spiny, spindle-shaped, with three annular septa. Length of the four +joints = 3 : 4 : 5 : 6. The third joint is the broadest, being twice as +broad as the constricted mouth. Pores irregular, roundish. Cephalis +conical, armed with a bunch of strong, conical spines, and distinguished by +double-contoured pores. Peristome with six (sometimes five or seven) +triangular, vertical, parallel, or slightly divergent feet. + +_Dimensions._--Length of the shell (with four joints) 0.18, breadth 0.09. +Length of the single joints, _a_ 0.03, _b_ 0.04, _c_ 0.05, _d_ 0.06. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +2. _Cyrtophormis ovata_, n. sp. + +Shell rough, ovate, very thick-walled, with three distinct strictures. +Length of the four joints = 1 : 1 : 2 : 3. The fourth joint is the +broadest, inversely hemispherical, and three times as broad as the +constricted mouth. Pores regular, circular, hexagonally framed. Cephalis +hemispherical, with a pyramidal horn of the same length. Peristome with a +coronal of six short, conical, curved, outwardly convex teeth. + +_Dimensions._--Length of the shell (with four joints) 0.2, breadth 0.14. +Length of the single joints, _a_ 0.02, _b_ 0.03, _c_ 0.06, _d_ 0.09. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + + +Subgenus 2. _Cyrtophormiscus_, Haeckel. + +_Definition._--Shell with nine (sometimes eight or ten) feet on the +peristome (three perradial alternate with six interradial). + + +3. _Cyrtophormis cingulata_, n. sp. (Pl. 78, fig. 18). + +Shell spiny, spindle-shaped, with three internal annular septa, and three +external girdles of spines. The second and third joints are of nearly equal +length, twice as broad as the first, and half as broad as the fourth joint. +The third joint is the broadest, and twice as broad as the constricted +mouth. Pores subregular, circular. Cephalis hemispherical, with a large +apical horn, and {1461}a coronal of six strong ascending spines. Peristome +beyond the stricture of the mouth somewhat dilated, with nine triangular, +divergent teeth (broken off in the specimen figured). + +_Dimensions._--Length of the shell (with four joints) 0.18, breadth 0.09. +Length of the single joints, _a_ 0.02, _b_ 0.04, _c_ 0.04, _d_ 0.08. + +_Habitat._--Western Tropical Pacific, Station 224, depth 1850 fathoms. + + +4. _Cyrtophormis aculeata_, n. sp. + +Shell spiny, slenderly ovate, with five distinct strictures, each with a +girdle of spines. The three middle joints are of nearly equal length, each +half as long as the second, and one-third as long as the sixth joint. The +fifth joint is the broadest, twice as broad as the constricted mouth. Pores +regular, circular. Cephalis conical, with a bunch of strong, divergent +spines. Peristome with nine strong, conical, vertical, parallel teeth. + +_Dimensions._--Length of the shell (with six joints) 0.18, breadth 0.08. +Length of the first joint 0.02, the second 0.04, the three following 0.02, +the sixth 0.06. + +_Habitat._--North Pacific, Station 241, depth 2300 fathoms. + + +5. _Cyrtophormis acutata_, Haeckel. + + _Eucyrtidium acutatum_, Stoehr, 1880, Palaeontogr., vol. xxvi. p. 105, + Taf. iv. fig. 11. + +Shell rough, spindle-shaped, with six annular strictures. The third, +fourth, and seventh joints are equal in length, three times as long as the +first and the fifth joints. The fourth joint is the broadest, four times as +broad as the constricted mouth. Pores irregular, roundish. Cephalis small, +subspherical, with a short conical horn. Peristome with nine (?) irregular, +triangular, little convergent teeth. + +_Dimensions._--Length of the shell (with seven joints) 0.22, breadth 0.11. +Length of the third, fourth, and seventh joints 0.04. + +_Habitat._--Fossil in Tertiary rocks of Sicily; Grotte (Stoehr). + + + +Subgenus 3. _Acanthocyrtis_, Haeckel. + +_Definition._--Shell with numerous (twelve to twenty or more) terminal +feet. + + +6. _Cyrtophormis cylindrica_, n. sp. (Pl. 77, fig. 17). + +Shell rough, subcylindrical, with three annular septa. The fourth +cylindrical joint is four times as long as the second and the third joints. +These three joints are nearly equal in breadth. Pores small and numerous, +almost square, in regular, transverse rows; two to three in the first +joint, five to six in the second and in the third, fourteen to sixteen in +the fourth joint. Cephalis flat, cap-shaped, with a short, pyramidal horn. +Peristome half as broad as the shell, hyaline, with a coronal of numerous, +very delicate, vertical feet. + +{1462}_Dimensions._--Length of the shell (with four joints) 0.2, breadth, +0.08. Length of the single joints, _a_ 0.02, _b_ 0.03, _c_ 0.03, _d_ 0.12. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +7. _Cyrtophormis corona_, n. sp. (Pl. 77, fig. 15). + +Shell smooth, conical, ovate, with three deep strictures, about twice as +long as broad. The fourth joint is the broadest, inflated, and three times +as long as the second and the third joints. Pores small and numerous, +circular, in regular, transverse rows; two in the first joint, four in the +second and third, and ten in the fourth joint. Cephalis hemispherical, with +a stout, pyramidal horn. Peristome two-thirds as broad as the fourth joint, +with twelve to fifteen triangular, convergent teeth. + +_Dimensions._--Length of the shell (with four joints) 0.16, breadth 0.08. +Length of the single joints, _a_ 0.01, _b_ 0.03, _c_ 0.03, _d_ 0.09. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +8. _Cyrtophormis cornuta_, n. sp. (Pl. 77, fig. 18). + +Shell thorny, spindle-shaped, with three distinct strictures. Length of the +four joints = 2 : 4 : 3 : 5. The third joint is the broadest. Pores +circular, of different sizes, in the three first joints double-contoured. +Cephalis subspherical, with a large, conical horn of three times the +length. The fourth joint is inversely conical, three times as broad as the +constricted mouth. Peristome with a coronal of numerous (ten to twenty) +irregular, thin, partly forked teeth. + +_Dimensions._--Length of the shell (with four joints) 0.14, breadth 0.07. +Length of the single joints, _a_ 0.02, _b_ 0.04, _c_ 0.03, _d_ 0.05. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +9. _Cyrtophormis fimbriata_, Haeckel. + + _Lithocampe fimbriata_, Stoehr, 1880, Palaeontogr., vol. xxvi. p. 103, + pl. iv. fig. 3. + +Shell rough, spindle-shaped, with six annular septa. The fifth joint is the +longest, twice as long as each of the three preceding joints, and four +times as long as the sixth. The fourth joint is the broadest, three times +as broad as the constricted mouth. Pores small, regular, circular. Cephalis +small, subspherical, with a small, conical horn (broken off in the specimen +figured). Peristome with an irregular, double coronal of ten to twenty +vertical teeth. + +_Dimensions._--Length of the shell (with seven joints) 0.25, breadth 0.1. +Length of the fifth joint 0.06, of each of the three preceding 0.03. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms; fossil in +Sicily (Grotte, Caltanisetta). + + +10. _Cyrtophormis turrita_, n. sp. + +Shell smooth, nearly conical, twice as long as broad, with twelve sharp +strictures. The thirteen joints increase gradually in length and breadth. +The last joint is much longer than any of {1463}the others, twice as long +as the eleventh, and twice as broad as the ninth joint. The constricted +mouth on its lower surface is only one-third as broad. Cephalis small, +hemispherical, with a short, conical horn. Peristome with a coronal of +twenty to thirty delicate, partly confluent, vertical teeth. + +_Dimensions._--Length of the shell (with thirteen joints) 0.26, breadth +0.12. + +_Habitat._--South-Eastern Pacific, Station 299 (off Valparaiso), depth 2160 +fathoms. + + +11. _Cyrtophormis turricula_, n. sp. (Pl. 75, fig. 5). + +Shell smooth, slender, tower-shaped, with fourteen distinct strictures. The +ten first joints are nearly equal in length. The twelfth joint is the +largest, three to four times as long as each of the preceding, and broader +than all the others, twice as broad as the suddenly constricted mouth. +Pores small and numerous, regular, circular, quincuncial. Cephalis small, +subspherical, with a pyramidal horn of three times the length. Peristome +with a coronal of twenty to thirty very delicate, partly confluent, short, +vertical teeth. + +_Dimensions._--Length of the shell (with fifteen joints) 0.3, breadth 0.1. +Length of the twelfth joint 0.05. + +_Habitat._--South-Eastern Pacific, Station 298 (off Valparaiso), depth 2225 +fathoms. + + + +Subfamily 2. STICHOPHAENIDA, Haeckel, 1881, Prodromus, p. 439. + +_Definition._--#Phormocampida# with the terminal mouth of the shell +fenestrated (vel Stichocyrtida multiradiata clausa). + + + +Genus 640. _Artophaena_,[257] Haeckel, 1881, Prodromus, p. 438. + +_Definition._--#Stichophaenida# (vel Stichocyrtida multiradiata clausa) +with six radial ribs or wings. + +The genus _Artophaena_ and the following genus _Stichophaena_ represent +together the small subfamily of Stichophaenida, or of those #Cyrtoidea# in +which the multiradiate shell is composed of numerous (four or more) joints, +and closed at the end by a lattice-plate. The number of the lateral, solid, +or latticed appendages is six in _Artophaena_, nine in _Stichophaena_. They +may have been derived either from the _Stichophormida_ by closure of the +terminal mouth, or from the _Stichoperida_ by intercalation of three or six +interradial appendages. + + +1. _Artophaena aerostatica_, n. sp. (Pl. 75, fig. 4). + +Shell four-jointed, with three sharp strictures and internal septa. The +fourth joint is subspherical, longer than the three first joints together, +and twice as broad as these. The second joint is {1464}twice as long as the +first and the third, and armed with six divergent, stout, pyramidal, radial +spines or wings of the same length. Cephalis flat, cap-shaped, with an +oblique pyramidal horn of twice the length. Pores regular, circular, +hexagonally framed. + +_Dimensions._--Length of the shell (with four joints) 0.18, breadth 0.12. +Length of the single joints, _a_ 0.02, _b_ 0.04, _c_ 0.02, _d_ 0.1. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +2. _Artophaena senaria_, n. sp. + +Shell pear-shaped, with five distinct strictures. Length of the four middle +joints little different. The fifth joint is the broadest. From the first +stricture there arise six radial ribs, which at the fourth are prominent as +six short, conical, divergent spines. The last joint is inversely +hemispherical, twice as long as the preceding. Cephalis hemispherical, with +a conical horn of the same length. Pores regular, circular. + +_Dimensions._--Length of the shell (with six joints) 0.14, breadth 0.09; of +each joint 0.02, of the last 0.04. + +_Habitat._--Central Pacific, Station 273, depth 2350 fathoms. + + +3. _Artophaena hexalatractus_, n. sp. + +Shell spindle-shaped, with three sharp strictures, and six triangular, +latticed, divergent wings, which arise from the collar stricture and +descend along the two middle joints. Their terminal points fall into the +same plane as the basal end of the fourth inversely conical joint. Length +of the four joints = 1 : 2 : 4 : 2. Cephalis hemispherical, with a conical +horn of the same length. (Similar to _Theophaena hexaptera_, Pl. 68, fig. +13, but with three distinct internal annular septa, corresponding to the +three external strictures.) + +_Dimensions._--Length of the shell (with four joints) 0.18, breadth 0.08. +Length of the four single joints, _a_ 0.02, _b_ 0.04, _c_ 0.08, _d_ 0.04. + +_Habitat._--South Pacific (off Juan Fernandez), Station 300, depth 1375 +fathoms. + + +4. _Artophaena hexapodiscus_, n. sp. + +Shell ovate, without external strictures, but with five internal annular +septa. Length of the six joints = 1 : 2 : 3 : 4 : 3 : 6. Cephalis +hemispherical, with a stout conical horn of twice the length. The last +joint is the broadest, inversely hemispherical. From the fourth and fifth +joints arise six divergent ribs, which are prolonged over the fifth +stricture into six triangular, divergent, fenestrated feet, about as long +as the last joint. Pores in the upper half of the shell regular, circular, +in the lower half irregular, roundish. + +_Dimensions._--Length of the shell (with six joints) 0.2, breadth 0.12. +Length of the single joints, _a_ 0.015, _b_ 0.025, _c_ 0.03, _d_ 0.04, _e_ +0.03, _f_ 0.06. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + + +{1465}Genus 641. _Stichophaena_,[258] Haeckel, 1881, Prodromus, p. 439. + +_Definition._--#Stichophaenida# (vel Stichocyrtida multiradiata clausa) +with nine radial ribs or wings. + +The genus _Stichophaena_ differs from the preceding _Artophaena_ in the +typical number of the radial lateral appendages, being nine in the former, +six in the latter. Usually these are simple ribs enclosed in the +shell-wall, more rarely prominent wings. + + + +Subgenus 1. _Stichophaenidium_, Haeckel. + +_Definition._--Last joint of the shell rounded, without basal spines. + + +1. _Stichophaena ritteriana_, n. sp. (Pl. 75, fig. 12). + +Shell pear-shaped, twice as long as broad, with seven internal annular +septa. The upper half is slenderly conical, composed of seven joints of +nearly equal length, gradually increasing in breadth. The lower half is +formed only by the eighth joint, which is very large, subglobose, inflated, +and as long as the seven other joints together. The spherical cephalis +bears a conical horn of the same length. From the thorax arise at equal +distances nine radial ribs in the form of thin, triangular lamellae, which +attain their greatest height in the sixth joint, and form nine elegant, +denticulate crests in the eighth joint. Pores small and numerous, +subregular, circular. This beautiful species is dedicated to my honourable +friend, Dr. Paul von Ritter, the magnanimous philanthropist and liberal +protector of free science, who founded in the University of Jena the first +professorial chair of Darwinism and phylogeny. + +_Dimensions._--Length of the shell (with eight joints) 0.24, breadth 0.12. +Length of each of the first seven joints 0.015; diameter of the +subspherical last joint 0.12. + +_Habitat._--South Pacific, Station 300 (off Juan Fernandez), depth 1375 +fathoms. + + +2. _Stichophaena darwiniana_, n. sp. + +Shell pear-shaped, twice as long as broad, with six distinct strictures. +The last joint is the broadest and twice as long as the sixth, three times +as long as each of the five preceding joints. The hemispherical cephalis +bears a conical horn of twice the length. From the third joint arise nine +radial ribs, which reach the sixth joint, but are not developed in the last +hemispherical joint. Pores irregular, roundish. + +_Dimensions._--Length of the shell (with seven joints) 0.2, breadth 0.1. +Length of five first joints, each 0.018 to 0.022, of the sixth 0.03, of the +seventh joint 0.06. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +{1466}3. _Stichophaena goetheana_, n. sp. + +Shell ovate, one and a half times as long as broad, rough, with five +internal annular septa. The six joints gradually increase in length and +breadth. The last joint is the broadest, and half as long as the five +others together. The hemispherical cephalis bears a pyramidal horn of twice +the length. From the thorax arise nine radial ribs, which attain their +greatest height in the fourth joint and reach the fifth joint, but are not +developed in the last ovate joint. Pores subregular, circular. + +_Dimensions._--Length of the shell (with six joints) 0.22, breadth 0.14. +Length of the single joints, _a_ 0.02, _b_ 0.025, _c_ 0.03, _d_ 0.035, _e_ +0.04, _f_ 0.7. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + + +Subgenus 2. _Stichophaenoma_, Haeckel. + +_Definition._--Last joint of the shell pointed, armed with a polar, basal +spine, or a bunch of spines. + + +4. _Stichophaena nonaria_, n. sp. (Pl. 76, fig. 6). + +Shell nearly spindle-shaped, with five or six distinct strictures. The +third joint is the broadest and longest, and twice as long as the second +and the fifth joints. Along the second or third middle joint (beginning +from the second or third) descend nine prominent longitudinal ribs. +Cephalis hemispherical, with two short, conical, divergent horns. Last +joint inversely conical, armed with several strong, conical, divergent +spines. + +_Dimensions._--Length of the shell (with seven joints) 0.23, of the third +joint 0.05, of the last 0.04; breadth 0.1. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +5. _Stichophaena novena_, n. sp. (Pl. 76, fig. 7). + +Shell nearly spindle-shaped, with eight or nine deep strictures. The third +joint is the broadest, campanulate, in its lower half with nine prominent +ribs, which disappear beyond the third stricture. The following joints are +alternately longer and shorter, and decrease gradually in breadth. Thorax +hemispherical. Cephalis small, hemispherical, with a conical horn of the +same length. Last joint also hemispherical, scarcely larger than the +cephalis, with a bunch of conical, divergent spines. + +_Dimensions._--Length of the shell (with nine joints) 0.25, of the third +joint 0.05, of the last 0.02; breadth 0.1. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + + +{1467}Family LXX. #LITHOCAMPIDA#, n. fam. + + _Artocorida et Artocapsida_, _Stichocorida et Stichocapsida_, Haeckel, + 1881, Prodromus, pp. 437-439. + +_Definition._--#Stichocyrtida# eradiata. (#Cyrtoidea# with an annulated +shell, divided by three or more transverse constrictions into four or more +annular joints, without radial apophyses.) + +The family #Lithocampida# comprises those #Cyrtoidea# in which the +lattice-shell is composed of numerous (four to eight or more) annular +joints, and bears no radial apophyses. It may be divided into two +subfamilies, differing in the shape of the terminal mouth. This is a simple +wide opening in the Stichocorida (and the united Artocorida), closed by a +lattice-plate in the Stichocapsida (and the allied Artocapsida). The +phylogenetic origin of the Lithocampida may be found in the Theocyrtida. + +The number of species of Lithocampida is very great, and amounts here to +more than one hundred and sixty whilst the total number of Stichocyrtida is +about two hundred and forty. They represent therefore, two-thirds of the +whole group, whilst one third is composed of the Podocampida and +Phormocampida. Ehrenberg has already described between forty and fifty +species in his genera _Eucyrtidium_ and _Lithocampe_; the majority of these +were fossils from Barbados. + +This large number of species may be easily increased by accurate researches +on the great masses of Lithocampida, which are found in the Radiolarian +ooze of the Challenger, and as fossils in Barbados. The variety in the +number, size, and proportion of the shell-joints and of the lattice-pores +is very great, and permits us to distinguish a far greater number of +species than are here described. Many species are cosmopolitan, and belong +to the most common forms of Radiolaria. + +This large number of species requires to be disposed in different genera, +but the distinction of these latter is a rather difficult task, since the +exterior of the shell, as well as its internal structure, offers no +striking differences (compare Pls. 78 to 80). In my Monograph (1862, pp. +312 to 319) I have already pointed out the difficulty of distinguishing +between _Lithocampe_ and _Eucyrtidium_. The general form of the shell +exhibits a continuous series of transformations, from a flat, conical, or +nearly discoidal form, through cylindrical to ovate, or spindle-shaped +shells, the wide open terminal mouth becoming more or less constricted, and +finally (in the Stichocapsida) closed. The absence or presence of an apical +horn may further serve for the distinction of genera. A peculiar small +group is represented by the Spirocampida (_Spirocyrtis_, _Spirocampe_, Pl. +76, figs. 11 to 17), the transverse latticed girdles separating the single +joints, which are usually parallel and horizontal, becoming here partly +connected, so that they form a descending spiral. + +{1468}_Synopsis of the Genera of Lithocampida._ + + ------------------------------------------------------------------------- + I. Subfamily Stichocorida. + Terminal mouth of the last shell-joint a simple wide opening. + -------------------- + All annular septa or transverse strictures of the shell separated, + parallel, not connected by a spiral line. + ------------------------------------------------------------------------- + { Conical, { With horn, 642. _Lithostrobus_. + Shell conical { gradually { + or cylindrical. { dilated. { No horn, 643. _Dictyomitra_. + Mouth of the { + last joint wide { Conical above, { + open, not { cylindrical { With horn, 644. _Stichocorys_. + distinctly { below. { + constricted. { + { Cylindrical or { With horn, 645. _Artostrobus_. + { subcylindrical. { + { { No horn, 646. _Lithomitra_. + + { { Last joint + { { not tubular, 647. _Eucyrtidium_. + { Cephalis with { + Shell ovate or { a horn. { Last joint a + spindle-shaped. { { long tube, 648. _Eusyringium_. + Mouth of the { + last joint { { Cephalis with + constricted. { Cephalis { tube. 649. _Siphocampe_. + { without horn. { + { { Cephalis + { { without tube, 650. _Lithocampe_. + ------------------------------------------------------------------------- + Annular septa or transverse strictures of the shell all or partly + obliquely descending and connected spirally. + ------------------------------------------------------------------------- + With horn, 651. _Spirocyrtis_. + + No horn, 652. _Spirocampe_. + ------------------------------------------------------------------------- + II. Subfamily Stichocapsida. + Terminal mouth closed by a lattice-plate. + ------------------------------------------------------------------------- + Last joint rounded, without a { With horn, 653. _Cyrtocapsa_. + vertical basal spine. { + { No horn, 654. _Stichocapsa_. + + Last joint conical, pointed, with { Cephalis + a vertical, basal spine. { with horn, 655. _Artocapsa_. + + + +Subfamily 1. STICHOCORIDA, Haeckel, 1881, Prodromus, p. 438. + +_Definition._--#Lithocampida# with the terminal mouth of the shell open +(vel Stichocyrtida eradiata aperta). + + + +Genus 642. _Lithostrobus_,[259] Buetschli, 1882, Zeitschr. f. wiss. Zool., +vol. xxxvi. p. 529. + +_Definition._--#Stichocorida# (vel Stichocyrtida eradiata aperta), with +conical shell, gradually dilated towards the wide open mouth. Cephalis with +a horn. + +The genus _Lithostrobus_ is probably the most primitive among the +Lithocampida, and comprises those forms of this family in which the +slender, conical shell is gradually dilated towards the wide, terminal +mouth, each joint being broader than the preceding. {1469}It may be derived +from _Theoconus_ by increase in the number of the joints. Some species are +distinguished by a curved axis, which gives them a horn-like appearance; +these may be separated as a peculiar genus, _Cornustrobus_. + + + +Subgenus 1. _Conostrobus_, Haeckel. + +_Definition._--Shell regularly conical, with straight axis; all joints +nearly equal in length, gradually increasing in breadth. + + +1. _Lithostrobus monostichus_, n. sp. + +Shell slenderly conical, smooth, with straight axis, and eight to ten deep +strictures. All joints nearly of the same length, gradually increasing in +breadth; the eighth joint twice as broad as the fourth. In each joint only +a single transverse series of small, circular, regular pores. Horn of the +cephalis conical, straight, of twice the length. (Similar to _Lithostrobus +tetrastichus_, Pl. 80, fig. 6, but in each joint there is only a single +series of pores.) + +_Dimensions._--Length of the shell (with ten joints) 0.2, of each joint +0.02; breadth of the fourth joint 0.03, of the eight 0.06. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +2. _Lithostrobus distichus_, n. sp. + +Shell conical, papillate, with straight axis, and four to six deep +strictures. All joints nearly of the same length, the fifth twice as broad +as the second. In each joint two transverse rows of large, circular pores. +Horn of the cephalis stout, straight, conical, of the same length. + +_Dimensions._--Length of the shell (with six joints) 0.18, of each joint +0.03; breadth of the second joint 0.04, of the fifth 0.08. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +3. _Lithostrobus tristichus_, Haeckel. + + _Lithostrobus cuspidatus_, Buetschli, 1882, Zeitschr. f. wiss. Zool., + vol. xxxvi. p. 529. + + _Eucyrtidium cuspidatum_, Bailey, 1856, Amer. Journ. Sci. and Arts, vol. + xxii, p. 5, pl. i. fig. 12. + +Shell slenderly conical, smooth, with straight axis, and eight to ten deep +strictures. All joints nearly of the same length, the eighth joint twice as +broad as the third. In each joint three transverse rows of pores. Horn of +the cephalis bristle-shaped, strongly curved, about as long as the shell +(Ehrenberg confounds this species with _Lithostrobus cuspidatus_). + +_Dimensions._--Length of the shell (with eight joints) 0.16, of each joint +0.02; breadth of the fourth joint 0.04, of the eighth 0.08. + +_Habitat._--North Pacific, Kamtschatka (Bailey); Station 241, depth 2300 +fathoms. + + +{1470}4. _Lithostrobus tetrastichus_, n. sp. (Pl. 80, fig. 6). + +Shell slenderly conical, smooth, with straight axis and six to eight deep +strictures. All joints nearly of the same length, the eighth joint twice as +broad as the second. In each joint four transverse rows of regular, +circular pores with very thin bars. Horn of the cephalis conical, strong, +curved, about as long as two joints. + +_Dimensions._--Length of the shell (with eight joints) 0.12, of each joint +0.015; breadth of the second joint 0.02, of the eighth 0.04. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +5. _Lithostrobus pentastichus_, n. sp. + +Shell slenderly conical, smooth, with straight axis, and six to eight +slight strictures. All joints nearly of the same length, the sixth twice as +broad as the third. In each joint five transverse rows of small circular +pores. Horn of the cephalis pyramidal, of twice the length. (Similar to +_Eucyrtidium cienkowskii_, Pl. 80, fig. 9, but regularly conical, with all +the joints equal in length.) + +_Dimensions._--Length of the shell (with eight joints) 0.2, of each joint +0.025; breadth of the third joint 0.04, of the sixth 0.08. + +_Habitat._--South Pacific, Station 298, depth 2225 fathoms. + + +6. _Lithostrobus hexastichus_, n. sp. (Pl. 80, fig. 15). + +Shell campanulate-conical, smooth, with straight axis, and six to eight +slight strictures. All joints nearly of the same length, the sixth joint +twice as broad as the second. In each joint six transverse rows of +subregular, hexagonal pores, with thin bars. Horn of the cephalis conical, +straight, of about the same length. (The specimen figured is a somewhat +irregular one; other specimens found afterwards were perfectly conical and +regular, with joints of equal length). + +_Dimensions._--Length of the shell (with six joints) 0.16, of each joint +0.027. + +_Habitat._--Central Pacific, Station 270 to 274, depth 2350 to 2925 +fathoms. + + + +Subgenus 2. _Cornustrobus_, Haeckel. + +_Definition._--Shell horn-shaped, conical, with curved axis; all joints +nearly equal in length, gradually increasing in breadth. + + +7. _Lithostrobus cyrtoceras_, n. sp. (Pl. 80, fig. 2). + +Shell horn-shaped, conical, with curved axis, smooth, with six to eight +deep strictures. All joints nearly of the same length, gradually increasing +in breadth; the sixth joint twice as broad as the second. In each joint +about four transverse series of regular circular pores. Horn of the +cephalis conical, slightly curved, of the same length. + +{1471}_Dimensions._--Length of the curved axis of the shell (with eight +joints) 0.24, length of each joint 0.03; breadth of the second joint 0.04, +of the sixth 0.08. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +8. _Lithostrobus leptoceras_, n. sp. + +Shell horn-shaped, slenderly conical, with curved axis (like a quadrant of +a circle), smooth, with twelve to fourteen slight strictures. All joints +nearly of the same length, the tenth twice as broad as the second. In each +joint only a single transverse row of small circular pores. Horn of the +cephalis curved, bristle-shaped, half as long as the shell. + +_Dimensions._--Length of the curved axis of the shell (with twelve joints) +0.18, length of each joint 0.15; breadth of the second joint 0.02, of the +tenth 0.04. + +_Habitat._--North Pacific, Station 253, depth 3125 fathoms. + + +9. _Lithostrobus caloceras_, n. sp. (Pl. 80, fig. 4). + +Shell horn-shaped, conical, with curved axis, smooth, with six to eight +deep strictures. All joints nearly of the same length, the sixth twice as +broad as the third. On each joint a single circle of very large roundish +pores, separated by two to four series of smaller pores. Horn of the +cephalis conical, curved, of twice the length. + +_Dimensions._--Length of the curved axis of the shell (with six joints) +0.12, length of each joint 0.02; breadth of the third joint 0.04, of the +sixth 0.08. + +_Habitat._--South Pacific, Station 297, depth 1775 fathoms. + + +10. _Lithostrobus macroceras_, n. sp. + +Shell horn-shaped, slenderly conical, with curved, nearly semicircular +axis, without external strictures, but with twelve to twenty internal +septal rings. All joints nearly of the same length, the twelfth twice as +broad as the third. On each joint three to four transverse rows of +subregular, small, hexagonal pores. Horn of the cephalis conical, curved, +of twice the length. + +_Dimensions._--Length of the curved axis of the shell (with sixteen joints) +0.32, length of each joint 0.02; breadth of the third joint 0.02, of the +twelfth 0.04. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + + +Subgenus 3. _Cyrtostrobus_, Haeckel. + +_Definition._--Shell conical (often more campanulate or irregular), with +straight axis; joints of different lengths. Cephalis not lobate. + + +{1472}11. _Lithostrobus conulus_, n. sp. (Pl. 80, fig. 1). + +Shell slenderly conical, smooth, with straight axis, and seven to ten +distinct strictures. Joints of different lengths; the fourth and fifth +about twice as long as the preceding and following joints, the former with +four to five, the latter with two to three transverse rows of large +irregular pores; the seventh joint twice as broad as the third. Horn of the +cephalis short, pyramidal. + +_Dimensions._--Length of the shell (with eight joints) 0.14, length of the +fifth joint 0.03; breadth 0.06. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +12. _Lithostrobus picus_, Buetschli. + + _Lithostrobus picus_, Buetschli, 1882, Zeitschr. f. wiss. Zool., vol. + xxxvi. p. 529. + + _Eucyrtidium picus_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 72, Taf. xi. fig. 1. + +Shell slenderly conical, smooth, with straight axis, and six to eight +slight strictures. Joints of different lengths, the second twice as long as +each of the three following, and four times as long as each of the last +joints; the sixth joint one and a-half times as broad as the second. Small +circular pores in regular transverse rows; six rows in the first and the +second, three rows in the third, fourth, and fifth, a single row in each of +the last joints. Horn of the cephalis cylindrical, half as long as the +shell. + +_Dimensions._--Length of the shell (with eight joints) 0.12, length of the +second joint 0.03; breadth 0.04. + +_Habitat._--Fossil in Barbados. + + +13. _Lithostrobus argus_, Buetschli. + + _Lithostrobus argus_, Buetschli, 1882, Zeitschr. f. wiss. Zool., vol. + xxxvi. p. 529. + + _Eucyrtidium argus_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 70, Taf. ix. fig. 1. + +Shell conical, thorny, with straight axis, and five to seven slight +strictures. Joints of different lengths, each of the three first twice as +long as each of the following. Pores large, roundish, in transverse rows; +three rows in the first and the second joints (which in the figure of +Ehrenberg are not separated), two rows in the third joint, a single row in +each of the following joints. Horn of the cephalis large, conical, curved, +half as long as the shell. + +_Dimensions._--Length of the shell (with seven joints) 0.2, length of the +fourth joint (and each following) 0.02; breadth 0.1. + +_Habitat._--Fossil in Barbados. + + +14. _Lithostrobus acuminatus_, Haeckel. + + _Eucyrtidium acuminatum_, Bury, 1862, Polycystins of Barbados, pl. i, + fig. 1. + +Shell slenderly conical, smooth, with straight axis, and four to six deep +strictures. Joints gradually increasing in length. Pores in regular, +transverse rows, commonly three rows in the first, four {1473}in the +second, five in the third, six in the fourth, seven in the fifth, &c. +(sometimes the increase of the number is more or less irregular). Horn of +the cephalis strong, conical, straight, about as long as the fourth or +sixth joint. + +_Dimensions._--Length of the shell (with six joints) 0.2; length of the +fourth joint 0.04, breadth 0.06. + +_Habitat._--Fossil in Barbados. + + +15. _Lithostrobus cuspidatus_, Haeckel. + + _Eucyrtidium cuspidatum_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 291, Taf. ii. fig. 15. + +Shell, slender, conical, smooth, with straight axis, and ten to twelve +distinct strictures. Joints gradually increasing slightly in length, the +tenth twice as long as the third. Pores circular, in regular transverse +rows; commonly two rows in the first, three in the second, four in the +third, seven in the eighth and following joints. Horn of the cephalis long, +bristle-shaped, curved. This species called _Eucyrtidium cuspidatum_ by +Ehrenberg, differs from _Lithostrobus tristichus_ (compare above), to which +Bailey had given the same name. + +_Dimensions._--Length of the shell (with ten joints) 0.2; length of the +tenth joint 0.03, breadth 0.06. + +_Habitat._--North Atlantic (Greenland, Ehrenberg); Station 348, depth 2450 +fathoms. + + +16. _Lithostrobus cornutella_, Buetschli. + + _Lithostrobus cornutella_, Buetschli, 1882, Zeitschr. f. wiss. Zool., + vol. xxxvi. p. 529. + + _Eucyrtidium cornutella_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 291, Taf. ii. fig. 14. + +Shell slender, conical, smooth, with straight axis, and seven to nine +slight strictures. Joints gradually increasing slightly in length, the +sixth or seventh about twice as long as the third. Pores circular, in +regular transverse rows; two or three in the three or four first joints, +three or four in the following, four or five in the last joints. Horn of +the cephalis thin, bristle-shaped, curved. + +_Dimensions._--Length of the shell (with eight joints) 0.1; length of the +eighth joint 0.01, breadth 0.04. + +_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Pacific; many stations, +surface. + + +17. _Lithostrobus tornatus_, Haeckel. + + _Eucyrtidium tornatum_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 292, Taf. ix. fig. 20. + +Shell campanulate-conical, smooth, with straight axis, and four to six deep +strictures. Joints broad, gradually increasing in length, the fifth twice +as long as the second. Pores small, circular, in regular transverse rows; +in the second and third joints three or four rows, in the fifth seven rows, +&c. Horn of the cephalis small, double or forked. + +{1474}_Dimensions._--Length of the shell (with five joints) 0.1; length of +the fifth joint 0.04, breadth 0.08. + +_Habitat._--Indian Ocean, Zanzibar, depth 2200 fathoms (Pullen). + + +18. _Lithostrobus seriatus_, n. sp. (Pl. 79, fig. 15). + +Shell slender, conical, smooth, with straight axis, and four or five deep +strictures. Joints little different in length, increasing towards the +inflated last joint, which is twice as long as the preceding. On each joint +four or five transverse rows of small circular pores. Horn small, +bristle-shaped, oblique. This common species is rather variable. + +_Dimensions._--Length of the shell (with five joints) 0.14; length of the +fifth joint 0.05, breadth 0.06. + +_Habitat._--Central Pacific, Stations 270 to 274, depth 2350 to 2925 +fathoms. + + +19. _Lithostrobus cornutus_, n. sp. (Pl. 77, fig. 6). + +Shell slender, conical, subcampanulate, smooth, with three or four deep +strictures. Joints of different lengths, the third and the fourth twice as +long as the second, four times as long as the first. Transverse rows of +small circular pores; three in the first joint, five in the second, eight +in the third and in the fourth. Horn large, pyramidal, about as long as the +third joint. + +_Dimensions._--Length of the shell (with four joints) 0.12; length of the +third joint 0.04, breadth 0.06. + +_Habitat._--Central Pacific, Station 265 to 268, depth 2700 to 2900 +fathoms. + + +20. _Lithostrobus microporus_, Buetschli. + + _Lithostrobus microporus_, Buetschli, 1882, Zeitschr. f. wiss. Zool., + vol. xxxvi. p. 529. + + _Eucyrtidium microporum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 291, Taf. xi. fig. 20. + +Shell slender, conical, smooth, very similar to the preceding species, +differs mainly in the more slender form and the smaller pores. The first +joint has four, the second eight, the third ten transverse rows of pores. +Horn conical, as long as the cephalis. The third joint in this and the +preceding species is campanulate, and large. + +_Dimensions._--Length of the shell (with four joints) 0.11; length of the +third joint 0.05, breadth 0.04. + +_Habitat._--Fossil in Barbados. + + +21. _Lithostrobus quadratus_, n. sp. + +Shell broad, conical, smooth, with straight axis, and six to eight deep +strictures. Joints of different lengths, usually alternately longer and +shorter. The seventh joint five times as broad as long, twice as long as +the sixth and the fourth; six transverse rows of pores in the seventh, +three {1475}in the sixth joint. Horn small, conical. This species differs +from all others in the subregular square form of the small pores. + +_Dimensions._--Length of the shell (with seven joints) 0.15; length of the +seventh joint 0.024, breadth 0.12. + +_Habitat._--Central Pacific, Station 271 to 274, depth 2350 to 2750 +fathoms. + + +22. _Lithostrobus hexagonalis_, n. sp. (Pl. 79, fig. 20). + +Shell broad, conical, smooth, with straight axis, and five to eight +prominent girdles between six and nine constricted broad joints. The first +and the third joints are half as long as the second, the fourth, and each +of the following joints. The sixth joint is five times as broad as long. +Pores subregular, hexagonal, in regular transverse rows; three to four rows +in the first and the second joints, six to eight in the third, the fourth, +and each following joint. Cephalis with some small spines, and a larger, +oblique, curved horn. + +_Dimensions._--Length of the shell (with six joints) 0.2; length of the +sixth joint 0.04, breadth 0.2. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + + +Subgenus 4. _Botryostrobus_, Haeckel. + +_Definition._--Shell conical, with straight axis, joints of different +lengths. Cephalis lobate, with some irregular constrictions. (Perhaps +derived from #Botryodea#?). + + +23. _Lithostrobus botryocyrtis_, n. sp. (Pl. 79, figs. 18, 19). + +Shell slender, conical, smooth, with straight axis, and three deep +strictures. Joints of different lengths. The length of the fourth joint +equals two-thirds of its breadth, and of the length of the three preceding +joints together. Each of the latter bears three transverse rows of small, +quadrangular pores, the fourth joint has six rows. The cephalis is +irregularly lobate, with four to six prominent lobes, and two small +divergent horns (fig. 19). + +_Dimensions._--Length of the shell (with four joints) 0.1; length of the +fourth joint 0.04, breadth 0.06. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +24. _Lithostrobus lithobotrys_, n. sp. (Pl. 79, fig. 17). + +Shell slender, conical, smooth, with straight axis, and four deep +strictures. Joints of different lengths, gradually increasing towards the +mouth, the length of the fifth joint equals half its breadth, and one-third +of the length of the whole shell. The single joints bear each four or five +transverse rows of small, roundish pores. Cephalis irregularly lobate, with +four to six prominent lobes, and the same number of small, conical horns. + +{1476}_Dimensions._--Length of the shell (with five joints) 0.12; length of +the fifth joint 0.04, breadth 0.08. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + + +Genus 643. _Dictyomitra_,[260] Zittel, 1876, Zeitschr. d. deutsch. geol. +Gesellsch., p. 80. + +_Definition._--#Stichocorida# (vel Stichocyrtida eradiata aperta), with +conical shell gradually dilated towards the wide open mouth. Cephalis +without horn. + +The genus _Dictyomitra_ agrees with the preceding _Lithostrobus_ in the +slender, conical form of the multiarticulate shell, but differs from it in +the absence of a horn on the cephalis; the horn is here completely lost. + + + +Subgenus 1. _Dictyomitrella_, Haeckel. + +_Definition._--Shell smooth, with joints nearly equal in length. + + +1. _Dictyomitra articulata_, Haeckel. + + _Eucyrtidium articulatum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 70, Taf. xi. figs. 2, 3. + +Shell slender, conical, smooth, with six to eight deep strictures. All +joints nearly equal in length, gradually increasing in breadth, the eighth +four times as broad as long, and twice as broad as the fourth joint. In +each joint three to four transverse series of small, regular, circular +pores. + +_Dimensions._--Length of the shell (with eight joints) 0.12, of each joint +0.015; breadth of the fourth joint 0.04, of the eighth joint 0.08. + +_Habitat._--Fossil in Barbados. + + +2. _Dictyomitra macilenta_, Haeckel. + + _Eucyrtidium macilentum_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 291, Taf. vii. fig. 15. + +Shell slender, conical, smooth, with five to seven deep strictures. All +joints nearly equal in length, gradually increasing in breadth, the sixth +joint three times as broad as long, and twice as broad as the second. In +each joint only two transverse series of small, regular, circular pores. + +_Dimensions._--Length of the shell (with seven joints) 0.08, of each joint +0.012; breadth of the sixth joint 0.036, of the second 0.018. + +_Habitat._--Western Tropical Pacific, Stations 200 to 225, in various +depths. + + +{1477}3. _Dictyomitra conica_, n. sp. + +Shell widely conical, with six to eight prominent strictures. All joints +nearly equal in length, gradually increasing in breadth, the eighth five +times as broad as long, and twice as broad as the third. In each joint +three to four transverse rows of regular, hexagonal pores. (Similar to +_Lithostrobus hexagonalis_, Pl. 79, fig. 20, but more slender, and without +cephalic horn.) + +_Dimensions._--Length of the shell (with seven joints) 0.16, of each joint +0.022; breadth of the sixth 0.08. + +_Habitat._--South Pacific, Station 295, depth 1500 fathoms. + + + +Subgenus 2. _Dictyomitrissa_, Haeckel. + +_Definition._--Shell smooth, with joints of very different lengths. + + +4. _Dictyomitra polypora_, Zittel. + + _Dictyomitra polypora_, Zittel, 1876, Zeitschr. d. deutsch. geol. + Gesellsch., p. 80, Taf. ii. fig. 1. + +Shell slender, conical, rough, with six to nine deep strictures. Breadth +and length of the joints gradually increasing, so that the eighth joint is +twice as long and broad as the third. Pores regular, circular, in +transverse rows, four rows in each joint, in the last joint five to six +rows. + +_Dimensions._--Length of the shell (with eight joints) 0.24; length of the +eighth joint 0.04, breadth 0.1; length of the third joint 0.02, breadth +0.05. + +_Habitat._--Fossil in secondary rocks of Northern Germany (chalk of +Brunswick, &c.), Zittel. + + +5. _Dictyomitra eurythorax_, n. sp. (Pl. 77, fig. 4). + + _Lithocampium eurythorax_, Haeckel, 1881, Prodromus, p. 437, et Atlas, + pl. lxxvii. fig. 4. + +Shell campanulate, conical, rough, with three deep strictures. Cephalis +small, hemispherical. Thorax large, inflated, hemispherical, with six +transverse rows of pores. Abdomen with two broader joints, together as long +as the thorax, each with three to four rows of pores. + +_Dimensions._--Length of the shell (with four joints) 0.14, of the thorax +0.06; breadth of the thorax 0.08, of the last joint 0.1. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +6. _Dictyomitra microcephala_, Haeckel. + + _Eucyrtidium microcephalum_, Ehrenberg, 1858, Monatsber. d. k. preuss. + Akad. d. Wiss. Berlin, p. 32; Abhandl. d. k. Akad. d. Wiss. Berlin, 1872, + p. 291, Taf. xi. fig. 24. + +Shell broadly conical, smooth, with six to eight distinct strictures. +Breadth of the joints gradually increasing, length unequal. The three first +joints short, only one-half or one-third as long as {1478}each of the +following joints; in each of the former three to four transverse rows, in +each of the latter six to eight transverse rows of small, regular, circular +pores. + +_Dimensions._--Length of the shell (with six joints) 0.09, of the three +first joints 0.03, of the three following 0.06; breadth of the sixth joint +0.08, of the fourth 0.04. + +_Habitat._--Mediterranean (Candia) Spratt, depth 1620 fathoms. + + +7. _Dictyomitra demersissima_, Haeckel. + + _Eucyrtidium demersissimum_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 291, Taf. vii. fig. 11. + +Shell slender, conical, smooth, with four internal septal rings (without +external strictures). Breadth of the five joints gradually increasing, +length unequal; the third joint the longest, twice as long as the second, +and longer than any of the following. Pores very small and numerous, in +longitudinal rows. + +_Dimensions._--Length of the shell (with five joints) 0.09, of the second +joint 0.015, of the third 0.03; breadth of the second joint 0.03, of the +third 0.05. + +_Habitat._--Tropical Pacific, Philippine Sea, depth 3300 fathoms. + + + +Subgenus 3. _Dictyomitroma_, Haeckel. + +_Definition._--Shell with longitudinal ribs and furrows between them, with +joints of different lengths. + + +8. _Dictyomitra costata_, n. sp. + +Shell slender, conical, with prominent longitudinal ribs, and six to eight +deep strictures. Length of the majority of joints nearly equal, the two or +three first joints shorter, the last a little longer. In each joint only a +single transverse series of pores at the distal end (one pore in each +furrow). (Similar to _Siphocampe tubulosa_, Pl. 79, fig. 13, but conical, +and without cephalic tube.) + +_Dimensions._--Length of the shell (with eight joints) 0.16, of each middle +joint 0.03, of the first 0.02; breadth of the last joint 0.06. + +_Habitat._--Central Pacific, Station 295, depth 1500 fathoms. + + +9. _Dictyomitra multicostata_, Zittel. + + _Dictyomitra multicostata_, Zittel, 1876, Zeitschr. d. deutsch. geol. + Gesellsch., p. 81, Taf. ii. figs. 2-4. + +Shell slender, conical, with prominent longitudinal ribs, and eight to ten +deep strictures. Length and breadth of the joints gradually increasing, the +eighth joint twice as long and broad as the fourth joint. Pores regular, +circular, one series in each longitudinal furrow, three to four pores on +each joint. + +{1479}_Dimensions._--Length of the shell (with eight joints) 0.2, of the +fourth joint 0.02, of the eighth joint 0.04; breadth of the fourth joint +0.04, of the eighth 0.08. + +_Habitat._--Fossil in secondary rocks of North Germany (chalk of Brunswick, +&c.), Zittel. + + + +Genus 644. _Stichocorys_,[261] Haeckel, 1881, Prodromus, p. 438 (_sensu +emendato_). + +_Definition._--#Stichocorida# (vel Stichocyrtida eradiata aperta) with a +middle constriction of the shell, the upper half of which is conical, the +lower cylindrical. Mouth truncate. Cephalis with a horn. + +The genus _Stichocorys_ is intermediate between the two preceding and the +two following genera; the upper half of the shell with the three first +joints is conical, the lower half with the fourth and the following joints +cylindrical, of equal breadth. The third joint of the shell (or the abdomen +of _Theoconus_) is constantly the largest, being broader than all the other +joints. _Stichocorys_ is a very common and characteristic form, and may be +derived from _Theoconus_ by development of a post-abdomen. + + +1. _Stichocorys wolffii_, n. sp. (Pl. 80, fig. 10). + +Shell in the upper half (with three joints) thorny, in the lower half (with +two joints) smooth. Pores of the former double-contoured, in subregular, +transverse rows. Pores of the latter smaller, simple, scarcely scattered. +Cephalis with a pyramidal horn of the same length. Thorax with prominent, +longitudinal divergent ribs. Dedicated to Caspar Friedrich Wolff (Halle, +1759). + +_Dimensions._--Length of the shell (with five joints) 0.16; breadth of the +third joint 0.08, of the fourth 0.05. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +2. _Stichocorys panderi_, n. sp. (Pl. 80, fig. 7). + +Shell in the upper conical half (with three joints) spiny, in the lower +subcylindrical half (with three joints) smooth. Pores small, circular, +irregularly scattered, simple. Cephalis with a conical horn of the same +length. No longitudinal ribs. Dedicated to Christian Pander (Wuerzburg, +1817.) + +_Dimensions._--Length of the shell (with six joints) 0.18; breadth of the +third joint 0.08, of the fourth 0.05. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +3. _Stichocorys baerii_, n. sp. (Pl. 80, fig. 8). + +Shell in the upper conical half (with three joints) spiny, in the lower +cylindrical half (with three joints) sulcate, with prominent longitudinal +ribs, alternating with longitudinal rows of small pores. {1480}Pores of the +upper half smaller, quincuncially disposed. Cephalis with a stout pyramidal +horn of the same length. Dedicated to Carl Ernst Baer (Koenigsberg, 1828). + +_Dimensions._--Length of the shell (with six joints) 0.2; breadth of the +third joint 0.09, of the fourth 0.07. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +4. _Stichocorys okenii_, n. sp. (Pl. 80, fig. 5). + +Shell smooth, without spines or ribs; the upper conical half (with three +joints) about the same length as the lower subcylindrical half (with three +joints). Pores subregular, circular, in the inflated third joint twice as +large as in the five other joints. At the lumbar stricture (between the +second and third joints) a coronal of nine very large pores. Cephalis with +a curved horn of half the length. Dedicated to Lorenz Oken (Jena, 1806). + +_Dimensions._--Length of the shell (with six joints) 0.2; breadth of the +third joint 0.09, of the fourth 0.07. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +5. _Stichocorys huschkei_, n. sp. (Pl. 80, fig. 3). + +Shell in the upper conical half (with three joints) thorny, in the lower +cylindrical half (with five joints) smooth, roundish. Pores irregularly +scattered, always double-contoured, in the second joint three times as +large as in the third. At the third stricture (between the third and fourth +joints) a coronal of larger pores. Cephalis with a small, conical horn of +half the length. No longitudinal ribs. Dedicated to Emil Huschke (Jena, +1832). + +_Dimensions._--Length of the shell (with eight joints) 0.18; breadth of the +third joint 0.08, of the fourth joint 0.07. + +_Habitat._--South Pacific, Station 285, depth 2375 fathoms. + + +6. _Stichocorys rathkei_, n. sp. + +Shell spiny, everywhere covered with short conical spines. The upper +conical part of the shell (with three joints) half as long as the lower +cylindrical part (with six joints). Pores irregular, roundish, in the +thorax twice to three times as large as in the eight other joints. Cephalis +with a pyramidal horn of the same length. No longitudinal ribs. Dedicated +to Heinrich Rathke (Koenigsberg, 1839). + +_Dimensions._--Length of the shell (with nine joints) 0.24; breadth of the +third joint 0.08, of the fourth joint 0.06. + +_Habitat._--North Pacific, Station 253, depth 3125 fathoms. + + +7. _Stichocorys muelleri_, n. sp. + +Shell in the upper conical part (with three joints) spiny, in the lower +cylindrical part (with seven joints) smooth. Pores in the former +irregularly scattered, roundish, in the latter circular, {1481}regularly +disposed in longitudinal series, alternate, with prominent ribs. The upper +conical part of the shell is about half as long as the lower cylindrical +part. Cephalis with a large, pyramidal horn of three times the length. +Dedicated to Johannes Mueller (Berlin, 1858). + +_Dimensions._--Length of the shell (with ten joints) 0.22; breadth of the +third joint 0.09, of the fourth joint 0.06. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + + +Genus 645. _Artostrobus_,[262] n. gen. + +_Definition._--#Stichocorida# (vel Stichocyrtida eradiata aperta) with +cylindrical shell, the upper pole of which is rounded, the lower truncate. +Cephalis with a horn. + +The genus _Artostrobus_ and the following _Dictyomitra_ differ from all the +other Stichocorida in the cylindrical or nearly cylindrical form of the +shell, all the joints of which are nearly equal in breadth, and are very +short, often with a single transverse row of pores only. The first joint or +cephalis is usually different from the following, often hemispherical or +cap-shaped joints. The last joint is truncate, and has a wide open mouth. +Since the constrictions between the single joints are often very slight, +some species are very similar to the Dicyrtide _Sethocorys_. + + + +Subgenus 1. _Artostrobulus_, Haeckel. + +_Definition._--A single transverse row of small, circular pores on each +joint. (Sometimes on the uppermost joints two or three rows.) + + +1. _Artostrobus annulatus_, Haeckel. + + _Cornutella annulata_, Bailey, 1856, Amer. Journ. Sci. and Arts, vol. + xxii. pl. i. fig. 5_a_, 5_b_. + + _Eucyrtidium annulatum_, Haeckel, 1862, Monogr. d. Radiol., p. 327. + +Shell slender, cylindrical, smooth, without external strictures, but with +ten to twenty internal annular septa. On each joint only a single +transverse row of small pores. Cephalis hemispherical, with a single or +double small horn. Each joint about four times as broad as long. + +_Dimensions._--Length of the shell (with twenty joints) 0.2; length of each +joint 0.01, breadth 0.04. + +_Habitat._--Arctic Ocean, Kamtschatka (Bailey); Greenland (Ehrenberg). + + +{1482}2. _Artostrobus elegans_, Haeckel. + + ? _Eucyrtidium elegans_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 70, pl. xi. fig. 12. + + ? _Eucyrtidium pauperum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 72, pl. xi. fig. 13. + +Shell cylindrical, smooth, with eight to ten internal annular septa. +Cephalis subspherical, with a short, conical horn. Thorax campanulate, with +two transverse rows of pores. Abdomen with six to eight equal joints, each +with a single row of pores. (May be described, perhaps, better as +_Theocyrtis elegans_. _Eucyrtidium pauperum_, Ehrenberg, _loc. cit._, may +be a variety of this species.) + +_Dimensions._--Length of the shell (with nine joints) 0.1; length of each +abdominal joint 0.01, breadth 0.03. + +_Habitat._--Fossil in Barbados. + + + +Subgenus 2. _Artostrobium_, Haeckel. + +_Definition._--All (or the majority) of the joints of the shell with +several transverse rows of pores, in variable number. + + +3. _Artostrobus auritus_, Haeckel. + + _Lithocampe aurita_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 84. + + _Lithocampe auricula_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 71. + + _Eucyrtidium auritum_, Ehrenberg, 1854, Mikrogeol., Taf. xxii. fig. 25. + + _Eucyrtidium auritum_, Stoehr, 1880, Palaeontogr., vol. xxvi. p. 104, + Taf. iv. fig. 7. + +Shell subcylindrical, with five sharp strictures. All six joints nearly +equal in length; each with four or five transverse rows of small pores. +Cephalis small, flat, hemispherical, with two or three small, conical, +oblique horns. Mouth of the sixth joint a little constricted. + +_Dimensions._--Length of the shell (with six joints) 0.12; length of each +joint (on an average) 0.02, breadth 0.04 to 0.05. + +_Habitat._--Fossil in Tertiary rocks of Sicily (Grotte, Caltanisetta). + + +4. _Artostrobus biseriatus_, n. sp. + +Shell cylindrical, smooth, with ten to twelve deep strictures. All joints +nearly equal in size; each with two transverse rows of small circular +pores. Cephalis hemispherical, with a long, bristle-shaped, curved horn. + +_Dimensions._--Length of the shell (with twelve joints) 0.24; length of +each joint 0.02, breadth 0.04. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms. + + +{1483}5. _Artostrobus articulatus_, n. sp. (Pl. 79, fig. 16). + +Shell subcylindrical, with elegant longitudinal ribs and five sharp +strictures. All six joints nearly equal in length, each with three or four +transverse rows of small circular pores. The middle joints twice as broad +as long. Cephalis hemispherical with a conical, oblique horn. + +_Dimensions._--Length of the shell (with six joints) 0.16, length of a +single joint 0.02 to 0.03, breadth 0.04 to 0.05. + +_Habitat._--Central Pacific, Stations 270 to 274, depth 2350 to 2925 +fathoms. + + + +Genus 646. _Lithomitra_,[263] Buetschli, 1882, Zeitschr. f. wiss. Zool., p. +529. + +_Definition._--#Stichocorida# (vel Stichocyrtida eradiata aperta) with +cylindrical shell, the upper pole of which is rounded, the lower truncate. +Cephalis without horn. + +The genus _Lithomitra_ differs from the preceding genus _Artostrobus_ in +the absence of a cephalic horn, and therefore bears to it the same relation +as _Dictyomitra_ does to _Lithostrobus._ In many species the joints are +very short, and bear only a single transverse row of pores, and since the +constrictions between the joints are often very slight, Lithomitra becomes +very similar to the Dicyrtide _Dictyocephalus_. + + + +Subgenus 1. _Lithomitrella_, Haeckel. + +_Definition._--A single transverse row of small circular pores on each +joint. (Sometimes on the uppermost joints two or three rows.) + + +1. _Lithomitra pachyderma_, Buetschli. + + _Lithomitra pachyderma_, Buetschli, 1882, Zeitschr. f. wiss. Zool., Vol. + xxxvi. p. 529. + + _Eucyrtidium pachyderma_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 72, Taf. xi. fig. 21. + + _Eucyrtidium imbricatum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 72, Taf. xi. fig. 22. + +Shell thick-walled, subcylindrical, with longitudinal ribs, slightly +dilated in the middle, with ten to twelve subequal joints. On the lower +edge of each joint a single row of small circular pores. No external +strictures. This and the following species (though separated by Ehrenberg +as four different species) may be united. + +_Dimensions._--Length of the shell (with ten joints) 0.11; length of each +joint 0.01 to 0.012, breadth 0.04. + +_Habitat._--Fossil in Barbados. + + +{1484}2. _Lithomitra acephala_, Buetschli. + + _Lithomitra acephala_, Buetschli, 1882, Zeitschr. f. wiss. Zool., vol. + xxxvi. p. 529. + + _Eucyrtidium acephalum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 70, Taf. xi. fig. 5. + + _Eucyrtidium obstipum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 70, Taf. xi. fig. 17. + +Shell nearly cylindrical, smooth, thick-walled, with twelve to sixteen +subequal joints. On each joint a single row of small circular pores. No +external strictures. Scarcely differing from the preceding species; the +joints are broader and shorter, the cephalis is larger (by union of some +joints?), and the ribs of the surface less distinct. + +_Dimensions._--Length of the shell (with twelve joints) 0.1; length of each +joint 0.006 to 0.009, breadth 0.04. + +_Habitat._--Fossil in Barbados. + + +3. _Lithomitra lineata_, Haeckel. + + _Lithocampe lineata_, Ehrenberg (partim), 1838, Monatsber. d. k. preuss. + Akad. d. Wiss. Berlin, p. 130; Mikrogeol., 1854, Taf. xxii. fig. 26. + + _Lithocampe lineata_, Haeckel, 1862, Monogr. d. Radiol., p. 316. + + _Eucyrtidium lineatum_, Ehrenberg, 1847, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, p. 43; Mikrogeol., 1854, Taf. xxxvi. fig. 16; Abhandl. + d. k. Akad. d. Wiss. Berlin, 1875, p. 72, Taf. xi. fig. 9. + + _Dictyomitra lineata_, Stoehr, 1880, Palaeontogr., vol. xxvi. p. 101, + Taf. iii. fig. 22. + +Shell subcylindrical, smooth, with longitudinal ribs, and four to eight +slight transverse strictures. Cephalis small, subspherical, with few small +pores. Thorax broader, with two or three transverse rows of pores. Each +succeeding (abdominal) joint with a single transverse row of small pores. +Variable and nearly related to the two preceding species (compare my +Monograph, _loc. cit._). + +_Dimensions._--Length of the shell (with six to eight joints) 0.06 to 0.08; +length of each joint (on an average) 0.01, breadth 0.03. + +_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Indian, Pacific, in +various depths; many stations; fossil in Secondary and Tertiary rocks of +many places. + + +4. _Lithomitra nodosaria_, n. sp. (Pl. 79, fig. 1). + +Shell subcylindrical, with longitudinal ribs, and five to eight transverse +strictures, and prominent girdles between them. On each girdle (at the +lowermost edge of each joint) a single transverse row of circular pores. +The three or four uppermost joints are united, and represent a conical +cephalis. + +_Dimensions._--Length of the shell (with six joints) 0.1; length of each +joint 0.01 to 0.15, breadth 0.04 to 0.06. + +_Habitat._--Central Pacific, Station 263 to 274, depth 2350 to 2925 +fathoms. + + +{1485}5. _Lithomitra eruca_, n. sp. (Pl. 79, fig. 3). + +Shell subcylindrical, diminishing slightly towards both ends, with ten to +fifteen slight strictures. On each joint a single transverse row of +circular pores, descending obliquely in the wall. The two or three first +joints form together a roundish cephalis. Usually each joint is three times +as broad as long. + +_Dimensions._--Length of the shell (with twelve joints) 0.2; length of each +joint (on an average) 0.016, breadth 0.05. + +_Habitat._--Central Pacific, Station 265 to 268, depth 2700 to 2900 +fathoms; fossil in Barbados. + + +6. _Lithomitra chrysalis_, n. sp. (Pl. 79, fig. 4). + +Shell subcylindrical, diminishing slightly towards both ends, with elegant +longitudinal ribs, and with five to eight slight strictures. Each of the +upper joints with two (or sometimes three) transverse rows of small pores; +each of the lower joints with only a single row. + +_Dimensions._--Length of the shell (with six joints) 0.11; length of each +joint 0.01 to 0.015, breadth 0.04 to 0.05. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + + +Subgenus 2. _Lithomitrissa_, Haeckel. + +_Definition._--All (or the majority) of the joints of the shell with +several transverse rows of pores, in variable number. + + +7. _Lithomitra cylindrica_, n. sp. + +Shell cylindrical, smooth, with twelve to sixteen internal septal rings +(without external strictures). On each joint two transverse rows of small, +regular, circular pores. The hemispherical cephalis also has two rows of +pores. Each joint is twice as broad as long. + +_Dimensions._--Length of the shell (with sixteen joints) 0.3; length of +each joint 0.02, breadth 0.04. + +_Habitat._--South Pacific, Station 297, depth 1775 fathoms. + + +8. _Lithomitra costata_, Haeckel. + + _Dictyomitra costata_, Stoehr, 1880, Palaeontogr., vol. xxvi. p. 101, + Taf. iii. fig. 23. + +Shell with longitudinal ribs, in the upper half conical, in the lower half +cylindrical, with six to eight slight strictures. Small, circular pores in +regular transverse rows; three rows in each upper joint, two rows in each +lower joint (the last joints sometimes confluent). + +{1486}_Dimensions._--Length of the shell (with eight joints) 0.15; length +of each joint 0.017 to 0.023, breadth 0.04 to 0.05. + +_Habitat._--Fossil in Tertiary rocks of Sicily; Grotte (Stoehr), +Caltanisetta (Haeckel). + + +9. _Lithomitra punctata_, Haeckel. + + _Lithocampe punctata_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 84. + + _Eucyrtidium punctatum_, Ehrenberg, 1854, Mikrogeol., Taf. xxii. fig. 24. + + _Dictyomitra punctata_, Stoehr, 1880, Palaeontogr., vol. xxvi. p. 101, + Taf. iii. fig. 24. + +Shell subcylindrical, smooth, with four to six distinct strictures. +Cephalis small, subspherical. Thorax campanulate-conical. Abdomen +cylindrical, with three to four equal joints. In each joint five to six +transverse rows of small, circular pores, quincuncially disposed. + +_Dimensions._--Length of the shell (with five joints) 0.1; length of each +joint (except the first) 0.02, breadth 0.05. + +_Habitat._--Fossil in Tertiary rocks of Sicily; Caltanisetta (Ehrenberg), +Grotte (Stoehr). + + +10. _Lithomitra seriolata_, Haeckel. + + _Eucyrtidium seriolatum_, Ehrenberg, 1858, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, p. 33. + + _Lithocampe seriolata_, Haeckel, Monogr. d. Radiol., p. 316. + +Shell subcylindrical, smooth, with four to six sharp strictures. Cephalis +small, hemispherical. Thorax conical. Abdomen cylindrical, with three to +five different joints of alternate sizes. Small circular pores in +transverse rows; three or four rows in the third and fifth joints, seven or +eight rows in the second, fourth, and sixth joints. + +_Dimensions._--Length of the shell (with six joints) 0.1; length of the +second and fourth joints 0.03, of the third and fifth joints 0.015. + +_Habitat._--Mediterranean, Crete (Ehrenberg), Corfu (Haeckel). + + +11. _Lithomitra hyperborea_, Haeckel. + + _Eucyrtidium hyperboreum_, Bailey, 1856, Amer. Journ. Sci. and Arts, vol. + xxii., pl. i. fig. 10. + + _Lithocampe hyperborea_, Haeckel, 1862, Monogr. d. Radiol., p. 315. + +Shell cylindrical, with prominent longitudinal ribs and six deep +strictures. Cephalis hemispherical. On each joint three to four transverse +rows of small, obsolete pores. Each joint is about twice as broad as long. + +_Dimensions._--Length of the shell (with six joints) 0.12; length of each +joint 0.02, breadth 0.04. + +_Habitat._--Arctic and Northern Pacific, Kamtschatka (Bailey). + + +{1487}12. _Lithomitra australis_, Haeckel. + + _Lithocampe australis_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, p. 187. + + _Lithocampe australis_, Haeckel, 1862, Monogr. d. Radiol., p. 315. + + _Eucyrtidium australe_, Ehrenberg, 1847, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, p. 43; Mikrogeol., 1854, Taf. xxxv., A 21, fig. 18. + +Shell subcylindrical, smooth, with five deep strictures. The two middle +joints somewhat larger than the two proximal and the two distal joints. +Pores small, circular, in regular, transverse rows; two rows in the first +and the sixth joints, five rows in the second and the fifth, seven or eight +rows in the third and fourth joints. The two latter are twice as broad as +long. + +_Dimensions._--Length of the shell (with six joints) 0.14; length of the +four smaller joints 0.017, of the two larger joints 0.035; breadth 0.06. + +_Habitat._--Antarctic Sea (lat. 78d 10' S., long. 162d W.) Ross. + + +13. _Lithomitra eminens_, Haeckel. + + _Lithocampe eminens_, Stoehr, 1880, Palaeontogr., vol. xxvi. p. 102, Taf. + iv. fig. 2. + +Shell subcylindrical, rough, with seven slight strictures. The two or three +middle joints half as long as the two preceding and the two following +joints. Cephalis small, subspherical. Pores small, in subregular, +transverse rows, on the fifth and sixth joints only two rows, on the +second, third, seventh, and eighth joints four to five rows. + +_Dimensions._--Length of the shell (with eight joints) 0.27; length of the +fifth and sixth joints 0.17, of the others 0.03 to 0.04; breadth 0.08. + +_Habitat._--Fossil in Tertiary rocks of Sicily, Grotte (Stoehr). + + +14. _Lithomitra infundibulum_, n. sp. (Pl. 79, fig. 5). + +Shell in the upper half subconical, in the lower half subcylindrical, +rough, with four slight strictures. Cephalis hemispherical. Thorax conical. +Abdomen subcylindrical, three-jointed. Pores of the second, third, and +fourth joints funnel-shaped, with very small inner, and larger +double-contoured outer aperture; on the thorax twelve transverse rows, on +the third and fourth joints five rows. Fifth joint with irregular, +polygonal pores. + +_Dimensions._--Length of the shell (with five joints) 0.2; length of the +thorax 0.06, breadth 0.08; length of each abdominal joint 0.04, breadth +0.08. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +Genus 647. _Eucyrtidium_,[264] Ehrenberg, 1847, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 54. + +_Definition_.--#Stichocorida# (vel Stichocyrtida eradiate aperta) with +ovate or spindle-shaped shell, the mouth of which is constricted, but not +prolonged into a tube. Cephalis with a solid horn. + +{1488}The genus _Eucyrtidium_ (as here stated in the definition) and the +three following nearly allied genera differ from the preceding Stichocorida +in the more or less constricted mouth, and the consequent ovate or +spindle-form of the multiarticulate shell. The middle joints of the latter +are broader than the upper and the lower joints. In the earlier definition +given in my Monograph (1862, pp. 312 to 320), the genus had a much wider +sense; but the very large number of species since detected requires a more +strict definition. Ehrenberg confounded in his genus _Eucyrtidium_ a large +number of very different #Cyrtoidea#. In his last works (1872, 1875) he +described not less than one hundred and eleven species, fifty-five fossil +and fifty-six living (eight fossil species being yet living). But, in +reality, these one hundred and three species belong to twenty or twenty-two +very different genera of #Cyrtoidea#. + + + +Subgenus 1. _Eucyrtis_, Haeckel, 1881, Prodromus, p. 438. + +_Definition._--All joints of the shell nearly of the same length (excepting +often the first). Surface smooth or rough, without spines. + + +1. _Eucyrtidium acuminatum_, Ehrenberg. + + _Eucyrtidium acuminatum_, Ehrenberg, 1847, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, p. 43; Mikrogeol., 1854, Taf. xii. fig. 27. + + _Eucyrtidium acuminatum_, Stoehr, 1880, Palaeontogr., vol. xxvi. p. 104, + Taf. iv. fig. 6. + + _Eucyrtidium acuminatum_, Haeckel, 1862, Monogr. d. Radiol., p. 326. + + _Lithocampe acuminata_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, p. 84. + +Shell smooth, slender, nearly spindle-shaped, without external strictures, +but with eight to nine internal septal rings. All joints (except the first) +nearly of the same length (or the upper somewhat longer). The fifth joint +is the broadest. Cephalis small, subspherical, with a short, conical horn. +Pores very small and numerous, regular, hexagonal, four to six on the +length of each joint. + +_Dimensions._--Length of the shell (with eight joints) 0.14; length of each +joint about 0.02; greatest breadth, in the fifth joint, 0.07. + +_Habitat._--Fossil in Tertiary rocks of Sicily (Caltanisetta, Grotte, &c.). + + +2. _Eucyrtidium tropezianum_, Haeckel. + + _Lithocampe tropeziana_, J. Mueller, 1858, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 42, Taf. vii. figs. 4, 5, 6. + + _Lithocampe tropeziana_, Haeckel, 1862, Monogr. d. Radiol., p. 326. + +Shell smooth, slender, nearly spindle-shaped, without external strictures, +but with seven or eight internal septal rings. All joints of the same +length. The fifth and sixth joints are the broadest. Cephalis +hemispherical, with a pyramidal horn of the same length. Pores very small +and numerous, regular, circular, hexagonally framed, five to six in the +length of each joint. (Very near to the preceding species, but more +regular, and with different pores.) + +{1489}_Dimensions._--Length of the shell (with eight joints) 0.16, length +of each joint 0.02; greatest breadth (in the fifth joint) 0.07. + +_Habitat._--Mediterranean, French shore, St. Tropez (J. Mueller), surface. + + +3. _Eucyrtidium hexagonatum_, n. sp. (Pl. 80, fig. 11). + +Shell smooth, ovate, with six to seven internal septal rings. All joints +(except the first) nearly of the same length; the sixth joint is the +broadest. The seventh and eighth joints (broken off in the specimen +figured) gradually decrease toward the constricted mouth, which is as broad +as the septum between the third and fourth joints. Cephalis and thorax +together pear-shaped, with circular pores, sharp lumbar stricture, and a +stout, pyramidal horn of the same length. The five or six abdominal joints +with regular, hexagonal pores, six or seven in course of the length of each +joint. + +_Dimensions._--Length of the shell (with eight joints) 0.2, length of each +joint 0.025 to 0.03; greatest breadth (in the sixth joint) 0.1. + +_Habitat._--Central Pacific, Stations 266 to 272, depth 2425 to 2925 +fathoms. + + +4. _Eucyrtidium fusiforme_, n. sp. + +Shell smooth, slender, spindle-shaped, without external strictures, but +with ten to twelve internal septal rings. All joints of the same length; +the sixth joint is the broadest. Cephalis conical, with a pyramidal horn of +the same length. Pores regular, circular, four or five in course of the +length of each joint. (Differs from all other species of the genus in the +regular, slender, spindle form; the constricted mouth of the last joint is +half as broad as the sixth joint.) + +_Dimensions._--Length of the shell (with twelve joints) 0.24, length of +each joint 0.02; greatest breadth (on the sixth joint) 0.06, of the mouth +0.03. + +_Habitat._--Indian Ocean, Maldive Islands (Haeckel, 1882), surface. + + +5. _Eucyrtidium doliolum_, n. sp. + +Shell smooth, barrel-shaped, or nearly spindle-shaped, with eight or nine +distinct strictures. All joints (except the first) of the same length; the +fourth joint is the broadest. Cephalis small, subspherical, with two short, +divergent, conical horns. Pores regular, circular, hexagonally framed, +three to four in course of the length of each joint. + +_Dimensions._--Length of the shell (with ten joints) 0.2, length of each +joint 0.022; greatest breadth (in the fourth joint) 0.08. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + + +Subgenus 2. _Stichocyrtis_, Haeckel, 1881, Prodromus, p. 438. + +_Definition._--All joints of the shell nearly of the same length (excepting +often the first). Surface spiny. + + +{1490}6. _Eucyrtidium spinosum_, n. sp. + +Shell spiny, slender, ovate, without external strictures, but with seven or +eight internal septal rings. Conical spines of different lengths are +scattered over the whole surface. All joints have nearly the same length; +the sixth is the broadest. Cephalis conical, with one large and two or +three smaller conical horns. Mouth constricted, half as broad as the shell. +Pores irregular, roundish, double-edged, three to four on the length of +each joint. + +_Dimensions._--Length of the shell (with eight joints) 0.16, length of each +joint 0.02; greatest breadth (on the sixth joint) 0.06. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +7. _Eucyrtidium chrysalidium_, n. sp. + +Shell spiny, spindle-shaped, with four to five slight strictures, above +each stricture a circle or girdle of conical spines (as in the similar +_Cyrtophormis cingulata_, Pl. 78, fig. 18). All joints (except the first) +have the same length. Cephalis subspherical, with a bunch of divergent +spines. Mouth constricted, only one-third as broad as the third joint, +which is the broadest. Pores subregular, circular, four to five on the +length of each joint. + +_Dimensions._--Length of the shell (with six joints) 0.18, length of each +joint 0.032; greatest breadth 0.08. + +_Habitat._--South Pacific, Station 302, depth 1450 fathoms. + + + +Subgenus 3. _Artocyrtis_, Haeckel. + +_Definition._--Joints of the shell of very different lengths. Surface +smooth or rough, without spines. + + +8. _Eucyrtidium profundissimum_, Ehrenberg. + + _Eucyrtidium profundissimum_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 293, Taf. vii. fig. 12. + +Shell smooth, campanulate, ovate, with three internal septal rings. Four +joints of different lengths. Cephalis subspherical, with a small +bristle-shaped horn. Thorax campanulate, nearly twice as long as each of +the two following joints, which are nearly equal in breadth. Terminal mouth +wide open, little constricted. Pores very small and numerous, regular, +hexagonal. + +_Dimensions._--Length of the shell (with four joints) 0.12; length of the +thorax 0.05, breadth 0.07. + +_Habitat._--Pacific; many Stations (Stations 206, 225, 253, 265, &c.), in +depths between 2000 and 4000 fathoms. + + +{1491}9. _Eucyrtidium anthophorum_, Haeckel. + + _Thyrsocyrtis anthophora_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 84, Taf. xii. fig. 9. + +Shell smooth, slender, ovate, with three slight strictures. Four joints of +different lengths. Cephalis subspherical, with a stout, club-shaped, +spinulate or branched horn of the same length. Second campanulate and third +subcylindrical joint about equal in size. Fourth joint only half as long, +with slightly constricted mouth (broken off in Ehrenberg's figure). Pores +small and numerous, regular, circular, quincuncial. + +_Dimensions._--Length of the shell (with four joints) 0.12; length of the +second and of the third joints 0.04, breadth 0.05 to 0.06. + +_Habitat._--Fossil in Barbados. + + +10. _Eucyrtidium hertwigii_, n. sp. (Pl. 80, fig. 12). + +Shell smooth, ovate, truncate, with three distinct strictures. Four joints +of different lengths. Cephalis campanulate, with an internal rod-cross, and +a stout pyramidal horn of the same length. Second joint campanulate. Third +joint larger, subcylindrical, with a variable number of irregular, +longitudinal ribs, some of which are prolonged into the second and fourth +joints. The latter is only half as long, and slightly constricted towards +the mouth. Pores small and numerous, subregular, circular. + +_Dimensions._--Length of the shell (with four joints) 0.22. Length of the +single joints, _a_ 0.03, _b_ 0.06, _c_ 0.08, _d_ 0.05; breadth, _a_ 0.03, +_b_ 0.1, _c_ 0.12, _d_ 0.11. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +11. _Eucyrtidium lagena_, Haeckel. + + _Eucyrtidium lagena_, Haeckel, 1862, Monogr. d. Radiol., p. 325, Taf. iv. + fig. 11. + + _Lithocampe lagena_, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 839. + +Shell smooth, bottle-shaped, with three distinct strictures. Four joints of +different sizes. Cephalis small, spherical, with a bristle-shaped horn of +the same length. Second joint conical, third subcylindrical, fourth +inflated, with slightly constricted mouth; their lengths about equal. Pores +subregular, hexagonal, large, with thin bars. + +_Dimensions._--Length of the shell (with four joints) 0.16; length of each +of the three lower joints about 0.05, breadth 0.05 to 0.064. + +_Habitat._--Mediterranean (Messina). + + +12. _Eucyrtidium teuscheri_, n. sp. (Pl. 77, fig. 5). + +Shell smooth, bottle-shaped, with three distinct strictures. Four joints of +different lengths. The third joint four times as long as each of the two +first joints, and longer than the fourth, which {1492}is little constricted +towards the mouth. The greatest breadth is in the middle of the shell. +Cephalis hemispherical, with a small, conical horn of the same length. +Pores large, circular, of variable sizes. Dedicated to Dr. Reinhold +Teuscher. + +_Dimensions._--Length of the shell (with four joints) 0.16. Length of the +single joints, _a_ 0.015, _b_ 0.02, _c_ 0.07, _d_ 0.055; breadth, _a_ 0.03, +_b_ 0.05, _c_ 0.08, _d_ 0.06. + +_Habitat._--Central Pacific, Stations 266 to 274, depth 2350 to 2925 +fathoms. + + +13. _Eucyrtidium buetschlii_, n. sp. (Pl. 77, fig. 7). + +Shell rough, slender, ovate, truncate, with three distinct strictures. Four +joints of different lengths; the third is the largest, inflated, +subspherical. Fourth joint subcylindrical, little constricted towards the +truncate mouth. Cephalis hemispherical, with a small, conical horn. Pores +circular, much larger in the third joint than in the three others. + +_Dimensions._--Length of the shell (with four joints) 0.16. Length of the +single joints, _a_ 0.02, _b_ 0.03, _c_ 0.06, _d_ 0.05; breadth, _a_ 0.03, +_b_ 0.07, _c_ 0.09, _d_ 0.07. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +14. _Eucyrtidium galatheae_, Ehrenberg. + + _Eucyrtidium galatheae_, Ehrenberg, 1854, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, p. 242. + +Shell smooth, campanulate, with three deep strictures. Four joints of +different lengths; the fourth joint is the broadest, twice as long as the +third and the second, three times as long as the hemispherical cephalis, +which bears a stout, pyramidal, oblique horn of twice the length. Mouth +little constricted. Pores regular, circular, in transverse rows, three rows +in each of the three first joints, five or six rows in the last joint. + +_Dimensions._--Length of the shell (with four joints) 0.12; length of the +fourth joint 0.05, breadth 0.07. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + +15. _Eucyrtidium galea_, Haeckel. + + _Eucyrtidium galea_, Haeckel, 1862, Monogr. d. Radiol., p. 324, Taf. vii. + figs. 8-10. + + _Lithocampe galea_, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 838. + +Shell smooth, helmet-shaped, with four sharp strictures. Five joints of +different lengths. Cephalis small, spherical, with a thin pyramidal horn of +the same length. Second joint conical, about as long as the third, longer +than the fourth and the fifth joints. The third joint is the broadest. +Pores regular, circular, small and numerous. + +_Dimensions._--Length of the shell (with five joints) 0.18; length of the +second and the third joints 0.05, of the fourth 0.03; breadth 0.08 to 0.1. + +_Habitat._--Mediterranean (Messina), surface. + + +{1493}16. _Eucyrtidium eruca_, Ehrenberg. + + _Eucyrtidium eruca_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 70, Taf. x. fig. 13. + +Shell smooth, slender, ovate, or nearly spindle-shaped, with four sharp +strictures. Five joints of different lengths, the third and fourth nearly +equal, twice as long as the fifth, one and a half times as long as the +second; the fourth joint is the broadest. Mouth little constricted. +Cephalis subspherical, with a small, conical horn. Pores small and +numerous, subregular, circular. + +_Dimensions._--Length of the shell (with five joints) 0.12 to 0.14; length +of the third and the fourth joints, 0.03 to 0.04, breadth 0.04 to 0.05. + +_Habitat._--Cosmopolitan; Atlantic, Pacific, in different depths; also +fossil in Barbados and Sicily. + + +17. _Eucyrtidium montiparum_, Ehrenberg. + + _Eucyrtidium montiparum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 72, Taf. ix. fig. 11. + +Shell rough, nearly spindle-shaped, with five deep strictures. Six joints +of different lengths, the third and fourth nearly equal, longer than the +fifth and the sixth joints; the fourth joint is the broadest. Mouth +slightly constricted. Cephalis very small, hemispherical, hyaline, with a +short, conical horn. Pores subregular, circular, twice as broad as in the +similar smaller preceding species. + +_Dimensions._--Length of the shell (with six joints) 0.2; length of the +third and the fourth joints 0.05, breadth 0.07 to 0.08. + +_Habitat._--Fossil in Barbados. + + +18. _Eucyrtidium cienkowskii_, n. sp. (Pl. 80, fig. 9). + +Shell smooth, subconical, with five distinct strictures. Six joints of +different lengths; the third joint conical, one and a half to two times as +long as each of the other joints; the fifth joint is the broadest. Mouth +wide, very slightly constricted. Cephalis hemispherical, with an oblique +pyramidal horn of the same length. Pores regular, circular, in dense +transverse rows; five to six rows in each of the three last joints, eight +to nine rows in the third joint. + +_Dimensions._--Length of the shell (with six joints) 0.16, length of the +third joint 0.04, of each following joint 0.02; greatest breadth (in the +fifth joint) 0.08. + +_Habitat._--South Pacific, Station 295, depth 1500 fathoms. + + +19. _Eucyrtidium elongatum_, Stoehr. + + _Eucyrtidium elongatum_, Stoehr, 1880, Palaeontogr., vol. xxvi. p. 105, + Taf. iv. fig. 10. + +Shell rough, slender, nearly spindle-shaped, variable in size and form, +with six to seven distinct strictures. Seven to eight joints of different +lengths, often alternately longer and shorter. The second {1494}and the +last joints are the longest, the third is the broadest. Mouth slightly +constricted (broken off in Stoehr's figure). Cephalis small, subspherical, +with a small, oblique, curved horn. Pores irregular. + +_Dimensions._--Length of the shell (with seven joints) 0.2; length of the +single joints, between 0.02 and 0.04, breadth 0.06 to 0.08. + +_Habitat._--Fossil in Sicily (Grotte, Caltanisetta). + + +20. _Eucyrtidium stoehrii_, n. sp. + +Shell smooth, spindle-shaped, gradually diminishing towards both ends, with +eight to ten distinct strictures. Nine to eleven joints of different +lengths; the two or three middle joints--fifth, sixth, and seventh--longer +and broader than the other joints; the broadest is the fifth joint, which +is twice to three times as long as the first and last joints. Cephalis +subspherical, with a conical horn of the same length. Terminal mouth +strongly constricted, one-half or one-third as broad as the fifth joint. +Pores small, regular, circular. + +_Dimensions._--Length of the shell (with ten joints) 0.22; length of the +largest (fifth joint) 0.03, breadth 0.09. + +_Habitat._--Central Pacific, Stations 270 to 274, depth 2350 to 2925 +fathoms. + + +21. _Eucyrtidium scalarium_, n. sp. + +Shell smooth, slender, ovate, with nine to ten deep strictures, and ten to +eleven separate step-like joints of different lengths. The sixth joint is +the longest, twice as long as the fourth, and three times as long as the +third and the last joint; the seventh and eighth joints are the broadest, +one and a half times as broad as the wide mouth. Cephalis hemispherical, +with a short pyramidal horn of the same length. Pores small and numerous, +subregular, square, in regular transverse rows; six rows in the sixth +joint, three rows in the last joint. (Somewhat similar to _Spirocyrtis +scalaris_, Pl. 76, fig. 14, but ovate, not conical and not spiral.) + +_Dimensions._--Length of the shell (with eleven joints) 0.22, breadth 0.11; +length of the last joint 0.01, of the sixth 0.03. + +_Habitat._--North Atlantic, Station 64, surface. + + + +Subgenus 4. _Acanthocyrtis_, Haeckel, 1881, Prodromus, p. 437. + +_Definition._--Joints of the shell of very different lengths. Surface +spiny. + + +22. _Eucyrtidium tricinctum_, n. sp. (Pl. 78, fig. 13). + +Shell spiny, spindle-shaped, with three distinct strictures. Four joints of +different lengths, the first and third half as long as the second and +fourth; the third joint is the broadest, four times as {1495}broad as the +strongly constricted mouth. Spines irregularly scattered over the lower +half of the shell, increasing in size towards the mouth. Pores subregular, +circular. + +_Dimensions._--Length of the shell (with four joints) 0.25. Length of the +single joints, _a_ 0.03, _b_ 0.08, _c_ 0.04, _d_ 0.09; breadth (of the +third joint) 0.1. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +23. _Eucyrtidium armatum_, n. sp. (Pl. 78, fig. 14). + +Shell spiny, spindle-shaped, with three distinct strictures. Four joints of +different lengths, the second and third joints of the same length, shorter +than the fourth joint; the third joint is the broadest, four times as broad +as the strongly constricted mouth. The latter, as well as the conical +cephalis, is armed with an irregular bunch of strong conical spines, while +numerous smaller spines are scattered over the whole surface. Pores +irregular, roundish, double-contoured. + +_Dimensions._--Length of the shell (with four joints) 0.2. Length of the +single joints, _a_ 0.02, _b_ 0.05, _c_ 0.05, _d_ 0.08; breadth (of the +third joint) 0.1. + +_Habitat._--Western Tropical Pacific, Station 224, depth 1850 fathoms. + + +24. _Eucyrtidium conostoma_, n. sp. (Pl. 78, fig. 16). + +Shell spiny, spindle-shaped, with four distinct strictures. Five joints of +different lengths, having the proportion = 1 : 2 : 3 : 6 : 10. The fourth +joint is the broadest, inflated, twice as broad as long. Cephalis small, +with a conical horn of the same length. Fifth joint inversely conical, with +a narrow mouth, broader than the cephalis. Short conical spines are +scattered over the whole surface. Pores subregular, circular. + +_Dimensions._--Length of the shell (with five joints) 0.22. Length of the +single joints, _a_ 0.01, _b_ 0.02, _c_ 0.03, _d_ 0.06, _e_ 0.1; breadth (of +the fourth joint) 0.09. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +25. _Eucyrtidium ehrenbergii_, n. sp. (Pl. 78, fig. 15). + +Shell spiny, spindle-shaped, with four distinct strictures (the first and +the fourth are by a mistake not distinctly figured). Five joints of +different lengths, having the proportion = 2 : 3 : 4 : 2 : 5. The third +joint is the broadest, twice as broad as long, and twice as broad as the +constricted mouth. Whole surface covered with strong spines. Pores +irregular, roundish. + +_Dimensions._--Length of the shell (with five joints) 0.16. Length of the +single joints, _a_ 0.02, _b_ 0.03, _c_ 0.04, _d_ 0.02, _e_ 0.05; breadth +(in the third joint) 0.08. + +_Habitat._--Western Tropical Pacific, Station 220, depth 1100 fathoms. + + +26. _Eucyrtidium ovatum_, n. sp. + +Shell spiny, inversely ovate, with five sharp strictures. Six joints of +different lengths, having the proportion = 1 : 3 : 2 : 1 : 1 : 3. The third +joint is the broadest, three times as broad as the {1496}constricted mouth. +Cephalis with a stout pyramidal horn of the same length. Whole surface +spiny. Pores irregular, roundish. + +_Dimensions._--Length of the shell (with six joints) 0.22. Length of the +single joints, _a_ 0.02, _b_ 0.06, _c_ 0.04, _d_ 0.02, _e_ 0.02, _f_ 0.06; +breadth (in the third joint) 0.11. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + + +Genus 648. _Eusyringium_,[265] Haeckel, 1881, Prodromus, p. 437. + +_Definition._--#Stichocorida# (vel Stichocyrtida eradiata aperta) with +ovate or spindle-shaped shell, the mouth of which is constricted, and +prolonged into a terminal cylindrical tube. Cephalis with a solid horn. + +The genus _Eusyringium_ differs from the preceding closely allied genus +_Eucyrtidium_ in the peculiar formation of the last shell-joint, +representing a narrow, cylindrical, fenestrated tube. It exhibits, +therefore, to the latter the same relation as _Theosyringium_ bears to +_Theocorys_. + + + +Subgenus 1. _Eusyringartus_, Haeckel. + +_Definition._--Shell with three strictures and four joints; the third joint +is the largest, inflated, and much broader than the three others. + + +1. _Eusyringium conosiphon_, n. sp. (Pl. 78, fig. 10). + +Shell with four joints, very thick-walled, rough. Cephalis hemispherical, +with a very stout, smooth, three-sided pyramidal horn of the same length +and breadth. Thorax hemispherical. Third joint subspherical, three times as +long, and twice as broad as the thorax, and of the same length as the +slender, inversely conical fourth joint. Pores in the three first joints +subregular, circular, in the fourth joint irregular. + +_Dimensions._--Length of the shell (with four joints) 0.25. Length of the +single joint _a_ 0.02, _b_ 0.03, _c_ 0.1, _d_ 0.1; breadth 0.12. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +2. _Eusyringium pachysiphon_, n. sp. (Pl. 78, fig. 11). + +Shell with four joints, very thick-walled, rough. Cephalis conical, with a +thick, dimpled, conical horn of the same length. Thorax hemispherical. +Third joint inflated, subspherical, and fourth joint slender, inversely +conical, as in the similar preceding species. Differs from the latter +{1497}mainly in the form of the cephalic horn, and the cylindrical tube of +the last joint. Pores subregular, circular. + +_Dimensions._--Length of the shell (with four joints) 0.3. Length of the +single joints, _a_ 0.03, _b_ 0.03, _c_ 0.12, _d_ 0.12; breadth 0.15. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +3. _Eusyringium macrosiphon_, n. sp. (Pl. 78, fig. 12). + +Shell with four joints, thick-walled, rough. Cephalis subspherical with a +large, dimpled, conical horn of twice the length. The three following +joints nearly of the same shape as in the two similar preceding species. It +differs from these in the smaller size, the larger cephalic horn, and the +longer tube of the fourth joint, which is twice as long as the subspherical +third joint (in the figure the lower half is broken off). Pores subregular, +circular. + +_Dimensions._--Length of the shell (with four joints) 0.3. Length of the +single joints, _a_ 0.03, _b_ 0.03, _c_ 0.08, _d_ 0.16; breadth 0.09. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +4. _Eusyringium leptosiphon_, n. sp. + +Shell with four joints, thin-walled, smooth. Cephalis subspherical, with a +large, dimpled, slender, conical horn of three times the length. Thorax +hemispherical. Third joint ovate, four times as long as the thorax, and of +the same length as the thin, cylindrical tube of the fourth joint. Differs +from the three preceding species in the more slender form and the thinness +of the tube. Pores irregular, roundish. + +_Dimensions._--Length of the shell (with four joints) 0.33. Length of the +single joints, _a_ 0.02, _b_ 0.03, _c_ 0.13, _d_ 0.15; breadth 0.1. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + +5. _Eusyringium sipho_, Haeckel. + + _Eucyrtidium sipho_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 72, Taf. ix. fig. 2. + +Shell with four joints, thick-walled, smooth. Cephalis subspherical, +hyaline, without pores, with a thick, conical horn of twice the length. +Thorax hemispherical. Third joint ovate, four times as long as the thorax, +and of the same length as the thin, cylindrical fourth joint. Pores +subregular, circular, in the fourth joint twice as broad as in the third, +and three times as broad as in the second joint. + +_Dimensions._--Length of the shell (with four joints) 0.22. Length of the +single joints, _a_ 0.02, _b_ 0.02, _c_ 0.09, _d_ 0.09; breadth 0.08. + +_Habitat._--Fossil in Barbados. + + +{1498}6. _Eusyringium fistuligerum_, Haeckel. + + _Eucyrtidium fistuligerum_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. + Wiss. Berlin, p. 70, Taf ix. fig. 3. + +Shell with four joints, thin-walled, smooth. Cephalis subspherical, with +numerous very small pores, and a stout, pyramidal horn of the same length. +Thorax hemispherical. Third joint subspherical, four times as long as the +thorax, and of the same length as the slender, inversely conical or +cylindrical, fourth joint. Pores irregular, roundish or circular, in the +fourth joint twice as broad as in the two preceding joints. + +_Dimensions._--Length of the shell (with four joints) 0.2. Length of the +single joints, _a_ 0.02, _b_ 0.02, _c_ 0.08, _d_ 0.08; breadth 0.09. + +_Habitat._--Fossil in Barbados. + + + +Subgenus 2. _Eusyringoma_, Haeckel. + +_Definition._--Shell with four or more strictures, and five or more joints; +the last joint is strongly constricted, and forms a narrow cylindrical +tube. + + +7. _Eusyringium lagenoides_, Haeckel. + + _Eucyrtidium lagenoides_, Stoehr, 1880, Palaeontogr., vol. xxvi. p. 104, + Taf. iv. fig. 8. + +Shell with five joints, and four sharp strictures, nearly spindle-shaped. +The third joint is twice as long as the second and the fourth. Cephalis +small, cap-shaped, with a thin conical horn of the same length. The fifth +joint is in Stoehr's figure broken off, but well conserved in a specimen +from Caltanisetta, and represents a slender cylindrical tube, with few +pores, half as long as the shell. Pores small, subregular, circular, +quincuncial. + +_Dimensions._--Length of the shell (with five joints) 0.24, breadth 0.08; +length of the third joint 0.06, of the second and the fourth 0.03, of the +fifth 0.1; breadth of the basal tube 0.027. + +_Habitat._--Fossil in Tertiary rocks of Sicily (Grotte, Caltanisetta). + + +8. _Eusyringium rhaphanus_, Haeckel. + + _Eucyrtidium rhaphanus_, Stoehr, 1880, Palaeontogr., vol. xxvi. p. 106, + Taf. iv. fig. 12. + +Shell with six or seven joints of very different lengths, in the upper half +campanulate, in the lower cylindrical. The second and the two last joints +are the longest. Cephalis small, subspherical, with a short conical horn. +The last joint is a narrow cylindrical tube of variable length, scarcely +one-fourth as broad as the preceding joints. Pores in the upper joints +regular, circular, in the lower irregular, roundish. + +_Dimensions._--Length of the shell (with seven joints) 0.2, breadth 0.1; +length of the second and last joints 0.03 to 0.04; breadth of the basal +tube 0.025. + +_Habitat._--Fossil in Tertiary rocks of Sicily (Grotte). + + +{1499}9. _Eusyringium siphonostoma_, n. sp. (Pl. 80, fig. 14). + +Shell with eight joints, in the upper half slender, conical, in the lower +half cylindrical. The single joints are separated by seven internal annular +septa. The third and the seventh joints are the largest, twice as long as +the three intercalated joints. Cephalis small, cap-shaped, with a conical +horn of twice the length. The last joint (broken off in the specimen +figured) is a narrow cylindrical tube, one-third as long and one-third as +broad as the shell. Pores regular, circular, quincuncial. + +_Dimensions._--Length of the shell (with eight joints) 0.24, breadth 0.08; +length of the single joints 0.02 to 0.04; breadth of the basal tube 0.03. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +10. _Eusyringium cannostoma_, n. sp. (Pl. 80, fig. 13). + +Shell with nine or ten joints, slender ovate. The single joints are +separated by eight or nine internal annular septa. The third joint is the +longest, about twice or three times as long as each following joint. +Cephalis hemispherical, with a curved, conical horn of the same length. The +last joint is a narrow, cylindrical tube, about as long as the third joint, +but only one-fourth as broad. Pores small, regular, circular, quincuncially +disposed, and hexagonally framed. + +_Dimensions._--Length of the shell (with ten joints) 0.22, breadth 0.08; +length of the third joint 0.04, of the other joints 0.01 to 0.02, of the +basal tube 0.04; breadth of the latter 0.02. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +Genus 649. _Siphocampe_,[266] Haeckel, 1881, Prodromus, p. 438. + +_Definition._--#Stichocorida# (vel Stichocyrtida eradiata aperta) with +ovate or spindle-shaped shell, the mouth of which is constricted, but not +prolonged into a tube. Cephalis with an oblique, open, apical tube. + +The genus _Siphocampe_ differs from the closely allied genera _Lithocampe_ +and _Eucyrtidium_ in a very remarkable character, viz., the development of +a hollow cylindrical tube on the cephalis. This probably serves for the +emission of a bunch of pseudopodia. It has the same position and the same +oblique direction on the cephalis as the solid apical horn of +_Eucyrtidium_. + + + +Subgenus 1. _Siphocampula_, Haeckel. + +_Definition._--All joints of the shell (excepting the first) are nearly +equal in length. + + +{1500}1. _Siphocampe tubulosa_, n. sp. (Pl. 79, fig. 13). + +Shell slender nearly spindle-shaped, with eight deep transverse strictures, +and elegant longitudinal ribs. Nine joints slightly different in length and +shape. Cephalis flat, cap-shaped, with three or four transverse rows of +small pores, and a cylindrical, oblique tubule of twice the length. Each +successive joint with a single transverse row of regular, circular pores at +its lower edge, separated by divergent, longitudinal ribs. Last joint +shorter, with a hyaline annular peristome of the same length. Mouth half as +broad as the middle part of the shell. + +_Dimensions._--Length of the shell (with nine joints) 0.24; length of each +joint (on an average) 0.02 to 0.03; breadth 0.08. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +2. _Siphocampe annulosa_, n. sp. (Pl. 79, fig. 10). + +Shell slender, subcylindrical, with nine slight transverse strictures, and +interrupted longitudinal ribs. Ten joints nearly equal in length and shape, +excepting the two first, which together form a hemispherical cephalothorax, +with six to eight transverse rows of pores. Tubule of the cephalis short +and wide, truncate, conical. Each of the eight abdominal joints with a +single transverse row of small pores. Mouth constricted, without tubulose +peristome, half as broad as the shell. + +_Dimensions._--Length of the shell (with ten joints) 0.18; length of each +joint (on an average) 0.02, breadth 0.07. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + +3. _Siphocampe caminosa_, n. sp. (Pl. 79, fig. 12). + +Shell slender, subcylindrical, with six deep transverse strictures. Seven +joints nearly equal in length and breadth. Cephalis hemispherical, with an +oblique, cylindrical tubule of twice the length (in the figure the greater +part is broken away). Small circular pores in transverse rows and in +variable number; usually three rows in the first and the last joint, five +rows in the fourth joint, four rows in each of the other joints. Mouth +constricted, with a short tubulose peristome, only one-third as broad as +the shell. + +_Dimensions._--Length of the shell (with seven joints) 0.18; length of each +joint (on an average) 0.025, breadth 0.055. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +4. _Siphocampe erucosa_, n. sp. (Pl. 79, fig. 11). + +Shell slender, nearly spindle-shaped, with five slight transverse +strictures. Six joints nearly equal in length. The two first joints are +united, and form together a hemispherical cephalothorax, with a short, +oblique, cylindrical tubule. Pores regular, circular, double-contoured, in +regular, transverse rows; two rows in the first and the last joints, four +rows in each of the four middle joints. Mouth constricted, without +peristome, only one-third as broad as the shell. + +{1501}_Dimensions._--Length of the shell (with six joints) 0.14; length of +each joint (on an average) 0.02, breadth 0.07. + +_Habitat._--Central Pacific, Station 270, depth 2925 fathoms. + + + +Subgenus 2. _Siphocampium_, Haeckel, 1881, Prodromus, p. 437. + +_Definition._--The joints of the shell are very different in length. + + +5. _Siphocampe quadrantalis_, n. sp. + +Shell nearly spindle-shaped, with three deep strictures. Four joints of +very different lengths. Cephalis subspherical with an oblique cylindrical +tubule of twice the length, and with few small pores. Thorax ovate, half as +long as the shell, with twelve transverse rows of small pores. Abdomen with +two short joints, each of which has two transverse rows of pores. Mouth +constricted, one-third as broad as the thorax. + +_Dimensions._--Length of the shell (with four joints) 0.18; length of the +thorax 0.1, breadth 0.08. + +_Habitat._--Western Tropical Pacific; North Coast of New Guinea, Station +220, depth 1100 fathoms. + + +6. _Siphocampe spiralis_, n. sp. (Pl. 79, fig. 14). + +Shell nearly spindle-shaped, with eight slight strictures. Nine joints of +very different lengths. Cephalis subspherical, with an oblique cylindrical +tubule of the same length, and numerous small pores. Thorax conical, +one-fourth as long as the shell, with eight transverse rows of small pores. +Abdomen with numerous prominent, spirally convoluted ribs, and spiral rows +of pores between them. The first abdominal joint is from two to three times +as long as each of the six following joints. Abdominal pores larger, +roundish, disposed in eleven transverse rows. Four rows in the first +abdominal joint, one row in each of the five following, and two rows in the +last joint. Mouth slightly constricted, two-thirds as broad as the shell. + +_Dimensions._--Length of the shell (with nine joints) 0.17, cephalis 0.02, +thorax 0.04, abdomen 0.11; breadth 0.06. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms; also +fossil in Barbados. + + + +Genus 650. _Lithocampe_,[267] Ehrenberg, 1838, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 128 (_sensu emendato_). + +_Definition._--#Stichocorida# (vel Stichocyrtida eradiata aperta) with +ovate or spindle-shaped shell, the mouth of which is constricted, but not +prolonged into a tube. Cephalis without horn and tube. + +{1502}The genus _Lithocampe_ is the oldest of all "Polycystina," being +founded by Ehrenberg in 1838 upon _Lithocampe radicula_. Afterwards +numerous other species, which belong to very different genera, were +described by him. In 1862 I attempted to give a more strict definition of +this genus in my Monograph (p. 312 to 315), and separated it from the +closely allied and often confounded _Eucyrtidium_ by the absence of a +cephalic horn. The great number of species afterwards discovered leads to +the stricter definition given above. + + + +Subgenus 1. _Lithocampula_, Haeckel. + +_Definition._--All joints of the shell (except often the first) are equal +or nearly equal in length. + + +1. _Lithocampe eupora_, Haeckel. + + _Eucyrtidium euporum_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 291, Taf. iv. fig. 30. + +Shell smooth, ovate or subconical, with three deep strictures. Four joints +equal in length, gradually increasing in breadth, each with three +transverse rows of regular, circular, hexagonally-framed pores; the fourth +joint is the broadest. Mouth little constricted, of the same breadth as the +third joint. + +_Dimensions._--Length of the shell (with four joints) 0.08; length of each +joint 0.02, greatest breadth 0.06. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms; North +Atlantic, depth 3600 fathoms (Morse). + + +2. _Lithocampe platycephala_, Haeckel. + + _Eucyrtidium platycephalum_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. + Wiss. Berlin, pp. 145, 293, Taf. iii. fig. 16. + +Shell smooth, subconical or slenderly ovate, with three slight strictures. +Four joints equal in length, slightly increasing in breadth towards the +mouth. The hemispherical cephalis with longitudinal ribs and irregular +pores, each of the three other joints with four transverse rows of regular, +circular pores. Mouth strongly constricted, half as broad as the third and +fourth joints. + +_Dimensions._--Length of the shell (with four joints) 0.12; length of each +joint 0.03, greatest breadth 0.06. + +_Habitat._--North Atlantic, depth 3600 fathoms (Morse). + + +3. _Lithocampe nereidum_, Haeckel. + + _Lithocampe nereidum_, Haeckel, 1862, Monogr. d. Radiol., p. 319. + + _Eucyrtidium nereidum_, Ehrenberg, 1854, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, p. 242; Mikrogeol., Taf. xxxv. B, _b_, fig. 22. + +Shell smooth, slenderly ovate, with four deep strictures. Five joints equal +in length, the fourth being the broadest. Each joint with three transverse +rows of small, regular, circular pores {1503}(sometimes in the fourth joint +there are four rows). Mouth constricted, half as broad as the fourth joint. +(In Ehrenberg's figure all five joints are delineated, but the greater part +of the hemispherical cephalis is broken off.) + +_Dimensions._--Length of the shell (with five joints) 0.1, of each joint +0.02; breadth of the fourth joint 0.05. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +4. _Lithocampe radicula_, Ehrenberg. + + _Lithocampe radicula_, Ehrenberg, 1838, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 130, Taf. iv. fig. 11.; Mikrogeol., 1854, Taf. xxii. fig. + 23_a_. + +Shell smooth, spindle-shaped, with five sharp strictures. Six joints equal +in length, each with four transverse rows of regular, circular, +double-edged pores. The third and fourth joints are the broadest, and +equal. The constricted mouth is not broader than the hemispherical +cephalis, scarcely one-fourth as broad as the third and the fourth joints. +This remarkable species is the oldest known skeleton of a Radiolarian, a +figure of it being given in 1838, _loc. cit._ (compare my Monograph, 1862, +p. 3, 4, 331). But this figure of Ehrenberg is not quite accurate, and +differs from other figures of the same species, which he afterwards (1854) +published in his Mikrogeologie (_loc. cit._). The best of these is fig. +23_a_ in pl. xxii., and is identical with the typical form (common in +Barbados), and according to this I have here framed my description. The +sixth joint possesses a distinct (though small) terminal mouth; when this +becomes closed, the species passes over into _Stichocapsa radicula_. + +_Dimensions._--Length of the shell (with six joints) 0.18, length of each +joint (on an average) 0.03; breadth of the third and fourth joints 0.08, of +the second and fifth 0.06, of the terminal mouth and the cephalis 0.03. + +_Habitat._--Fossil in Tertiary rocks of Barbados. + + +5. _Lithocampe ventricosa_, Haeckel. + + _Dictyomitra ventricosa_, Stoehr, 1880, Palaeontogr., vol. xxvi. p. 102, + Taf. iii. fig. 25. + +Shell ovate, with six slight strictures. Seven joints nearly equal in +length, each with four (or sometimes three or five) transverse rows of +small, regular, circular pores, in the last joint the pores are larger. The +fourth and fifth joints are the broadest, and are twice as broad as the +constricted mouth. + +_Dimensions._--Length of the shell (with seven joints) 0.13 to 0.14; length +of each joint 0.017 to 0.02, greatest breadth 0.083, mouth 0.04. + +_Habitat._--Fossil in Tertiary rocks of Sicily; Grotte, Caltanisetta. + + +6. _Lithocampe fusiformis_, n. sp. + +Shell smooth, spindle-shaped, decreasing uniformly towards the two blunt +poles, with eight or nine sharp strictures, and nine or ten joints of equal +lengths, each with four transverse rows of regular, {1504}hexagonal pores. +The fourth and fifth joints are the broadest. The constricted mouth is +twice as broad as the hemispherical cephalis, half as broad as the fourth +joint. + +_Dimensions._ --Length of the shell (with ten joints) 0.2, of each joint +0.02; breadth of the fourth joint 0.06, mouth 0.03. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +Subgenus 2. _Lithocampium_, Haeckel, 1881, Prodromus, p. 437. + +_Definition._--The joints of the shell are very different in length. + + +7. _Lithocampe ovata_, n. sp. (Pl. 77, fig. 1). + +Shell smooth, urceolate or ovate, with three sharp strictures. Four joints +of different lengths, having the proportion 1 : 2 : 2 : 6. The fourth joint +is inflated and the broadest. The mouth is constricted, short, tubular, of +the same breadth as the hemispherical cephalis. Pores small, circular, in +regular transverse rows; four rows in the first, four in the second, two in +the third, and five in the fourth joint. The middle stricture is crossed by +longitudinal ribs. + +_Dimensions._--Length of the shell (with four joints) 0.11. Length of the +single joints, _a_ 0.01, _b_ 0.02, _c_ 0.02, _d_ 0.06; greatest breadth +0.055. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +8. _Lithocampe aquilonaris_, Haeckel. + + _Lithocampe aquilonaris_, Haeckel, 1862, Monogr. d. Radiol., p. 317. + + _Eucyrtidium aquilonare_, Bailey, 1856, Amer. Journ. Sci. and Arts, vol. + xxii. p. 4, pl. i. fig. 9. + +Shell smooth, subconical, with three distinct strictures. Four joints of +different lengths, having the proportion 3 : 1 : 3 : 4. The fourth joint is +the broadest, suddenly constricted, with a short tubular mouth of half the +breadth. Pores subregular, circular, in transverse rows; three rows in the +first joint, two in the second, four in the third, and three in the fourth +joint. + +_Dimensions._--Length of the shell (with four joints) 0.11. Length of the +single joints, _a_ 0.03, _b_ 0.01, _c_ 0.03, _d_ 0.04; breadth 0.06. + +_Habitat._--North Pacific, Kamtschatka (Bailey), Station 241, depth 2300 +fathoms. + + +9. _Lithocampe quadrarticulata_, Haeckel. + + _Lithocampe quadrarticulata_, Haeckel, 1862, Monogr. d. Radiol., p. 319. + + _Eucyrtidium quadrarticulatum_, Ehrenberg, 1861, Monatsber. d. k. preuss. + Akad. d. Wiss. Berlin, p. 299. + +Shell smooth, spindle-shaped, with three deep strictures. Four joints of +different lengths = 1 : 3 : 4 : 3. The third joint is the broadest, being +twice as broad as the constricted mouth of the fourth joint. Pores small, +regular, circular, in transverse rows; two being in the first, three in the +second, four in the third, three in the fourth joint. + +{1505}_Dimensions._--Length of the shell (with four joints) 0.11. Length of +the single joints, _a_ 0.015, _b_ 0.03, _c_ 0.04, _d_ 0.025; greatest +breadth 0.05. + +_Habitat._--North Atlantic (Greenland, depth 1600 fathoms, Ehrenberg), +Station 64, surface. + + +10. _Lithocampe multiseriata_, Haeckel. + + _Eucyrtidium multiseriatum_, Ehrenberg, 1872, Monatsber. d. k. preuss. + Akad. d. Wiss. Berlin, page 293, Taf. vii. fig. 9. + +Shell smooth, spindle-shaped, or slenderly ovate, with three sharp +strictures. Four joints of different lengths = 3 : 4 : 5 : 10. The third +and fourth joints nearly equal in breadth, and twice as broad as the +hemispherical cephalis. The truncate mouth is slightly constricted. Pores +very small and numerous, in regular transverse rows. Three or four rows in +the first, five or six in the second, seven or eight in the third, and +fifteen to twenty in the fourth joint. + +_Dimensions._--Length of the shell (with four joints) 0.11. Length of the +single joints, _a_ 0.015, _b_ 0.02, _c_ 0.025, _d_ 0.05; breadth 0.045. + +_Habitat._--Tropical Pacific (Philippine Sea, Ehrenberg), Stations 206, +224, 266, in various depths. + + +11. _Lithocampe diploconus_, n. sp. (Pl. 77, fig. 3). + +Shell rough, doubly conical, with three distinct strictures. Four joints of +different lengths = 2 : 5 : 5 : 8. The third joint is the broadest. The +three first joints form together a broad cone, and the fourth an inverse +truncate cone; the latter is distinguished by convergent longitudinal ribs. +Pores regular, circular, alternating with the ribs in the fourth joint. +Truncate mouth hyaline, half as broad as the third joint. + +_Dimensions._--Length of the shell (with four joints) 0.2. Length of the +single joints, _a_ 0.02, _b_ 0.05, _c_ 0.05, _d_ 0.08; breadth (in the +middle part) 0.1. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +12. _Lithocampe diaphana_, Haeckel. + + _Eucyrtidium diaphanum_, Ehrenberg, 1872, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, p. 309. + +Shell smooth, hyaline, spindle-shaped, decreasing uniformly towards both +poles, with three distinct strictures. Four joints of different lengths; +the second and third equal in breadth, twice as broad and three times as +long as the first and the fourth. Pores very small and scarce, in +transverse interrupted rows, commonly two rows in the first, two or three +in the second, three or four in the third, and only one in the last joint. +Mouth constricted, two-thirds as broad as the fourth joint. + +_Dimensions._--Length of the shell (with four joints) 0.13. Length of the +single joints, _a_ 0.015, _b_ 0.05, _c_ 0.05, _d_ 0.015; breadth (in the +middle part) 0.06, mouth 0.02. + +_Habitat._--South Atlantic, Station 335, depth 1425 fathoms. + + +{1506}13. _Lithocampe hispida_, Haeckel. + + _Lithocampe hispida_, Haeckel, 1862, Monogr. d. Radiol., p. 318. + + _Eucyrtidium hispidum_, Ehrenberg, 1861, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, p. 298; Abhandl. d. k. Akad. d. Wiss. Berlin, 1872, p. + 291, Taf. ii. fig. 19. + +Shell thorny, slenderly ovate, or nearly spindle-shaped, with four sharp +strictures. Five joints of different lengths = 3 : 3 : 4 : 6 : 4. The +fourth joint is the broadest, and nearly twice as broad as the constricted +mouth. Pores small, circular, separated by longitudinal, spiny ribs, +regularly disposed in transverse rows; three rows in the first and second, +four rows in the third and fifth, six rows in the fourth joint. + +_Dimensions._--Length of the shell (with five joints) 0.1. Length of the +single joints, _a_ 0.015, _b_ 0.015, _c_ 0.02, _d_ 0.03, _e_ 0.02; greatest +breadth 0.05. + +_Habitat._--Arctic Ocean (in different depths), Ehrenberg. + + +14. _Lithocampe tumidula_, Haeckel. + + _Lithocampe tumidula_, Haeckel, 1862, Monogr. d. Radiol., p. 318. + + _Eucyrtidium tumidulum_, Bailey, 1856, Amer. Journ. Sci. and Arts, vol. + xxii. p. 5, pl. i. fig. 11. + + _Eucyrtidium tumidulum_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 293, Taf. ii. fig. 12. + + ? _Eucyrtidium increscens_, Ehrenberg, 1861, Monatsber. d. k. preuss. + Akad. d. Wiss. Berlin, p. 299. + + ? _Lithocampe increscens_, Haeckel, 1862, Monogr. d. Radiol., p. 318. + +Shell smooth, nearly spindle-shaped, with four sharp strictures, very +similar to the preceding in size and form. It differs in the smooth +surface, the absence of longitudinal ribs, and the unequal size of the +pores, which form four transverse series in each joint, and are much larger +in the broadest (fourth) joint. Proportion of the five joints = +2 : 2 : 3 : 5 : 4. + +_Dimensions._--Length of the shell (with five joints) 0.1. Length of the +single joints, _a_ 0.012, _b_ 0.012, _c_ 0.02, _d_ 0.03, _e_ 0.025; +greatest breadth 0.05. + +_Habitat._--Cosmopolitan; Atlantic, Pacific; many stations, in different +depths. + + +15. _Lithocampe heteropora_, Haeckel. + + _Lithocampe heteropora_, Haeckel, 1862, Monogr. d. Radiol., p. 317. + + _Eucyrtidium heteroporum_, Ehrenberg, 1854, Monatsber. d. k. preuss. + Akad. d. Wiss. Berlin, p. 242. + +Shell smooth, subconical, obtuse, with four distinct strictures. Five +joints of different lengths = 2 : 4 : 3 : 3 : 2. The fourth joint is the +broadest. Mouth slightly constricted. Pores regular, circular, in the +second joint much larger than in the four others, disposed in transverse +series; two rows in the first and fifth, three rows in the second, four +rows in the third and fourth joints. + +_Dimensions._--Length of the shell (with five joints) 0.14. Length of the +single joints, _a_ 0.02, _b_ 0.04, _c_ 0.03, _d_ 0.03, _e_ 0.02; greatest +breadth 0.07. + +_Habitat._--North Atlantic (depth 2000 fathoms, Ehrenberg), Canary Islands, +surface, Haeckel. + + +{1507}16. _Lithocampe meta_, Stoehr. + + _Lithocampe meta_, Stoehr, 1880, Palaeontogr., vol. xxvi. p. 103, Taf. + iv. fig. 4. + +Shell rough, subconical, obtuse, with four slight strictures. Five joints +of different lengths = 2 : 4 : 5 : 4 : 2. The fourth joint is the broadest, +and three times as broad as the constricted mouth. Pores, small, regular, +circular, quincuncially disposed, equal in size; two transverse rows in the +first and fifth, five rows in the second and fourth, six rows in the third +joint. + +_Dimensions._--Length of the shell (with five joints) 0.14. Length of the +single joints, _a_ 0.017, _b_ 0.033, _c_ 0.04, _d_ 0.033, _e_ 0.017; +greatest breadth 0.083. + +_Habitat._--Fossil in Tertiary rocks of Sicily, Grotte (Stoehr), +Caltanisetta (Haeckel). + + +17. _Lithocampe urceolata_, n. sp. (Pl. 77, fig. 2). + +Shell rough, wide, urceolate, without external strictures, but with four +internal septal rings (not visible in the figure), each of which contains +an internal circle of horizontal pores. Five joints of different lengths = +2 : 3 : 6 : 4 : 2. The third joint is the broadest, and three times as +broad as the constricted mouth. Pores of very different sizes, irregular, +roundish, with prominent polygonal frames. A very remarkable species. + +_Dimensions._--Length of the shell (with five joints) 0.17. Length of the +single joints, _a_ 0.02, _b_ 0.03, _c_ 0.06, _d_ 0.04, _e_ 0.02; greatest +breadth 0.13. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +18. _Lithocampe clava_, Ehrenberg. + + _Lithocampe clava_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 66, Taf. iv. fig. 2. + +Shell smooth, club-shaped, or slenderly ovate, with five internal septal +rings. Six joints of very different lengths = 5 : 2 : 3 : 4 : 5 : 18. The +sixth joint is the broadest, and as long as the five others together. Pores +small, circular, in the basal half of the last joint irregular and larger. +Constricted mouth as broad as the subspherical, hyaline cephalis. + +_Dimensions._--Length of the shell (with six joints) 0.15. Length of the +single joints, _a_ 0.02, _b_ 0.011, _c_ 0.013, _d_ 0.016, _e_ 0.02, _f_ +0.07. + +_Habitat._--Fossil in Barbados. + + +19. _Lithocampe hexacola_, n. sp. (Pl. 79, fig. 7). + +Shell smooth, nearly spindle-shaped, without external strictures, but with +five internal septal rings. Six joints of different lengths = +4 : 8 : 5 : 5 : 5 : 10. The fourth joint is the broadest, and four times as +broad as the constricted mouth. Pores subregular hexagonal, or irregular +polygonal, with thin bars. + +_Dimensions._--Length of the shell (with six joints) 0.18, greatest breadth +0.09. Length of the six joints, _a_ 0.02, _b_ 0.04, _c_, _d_, and _e_ each +0.025, _f_ 0.05. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +{1508}20. _Lithocampe heptacola_, n. sp. (Pl. 79, fig. 8). + +Shell smooth, subcylindrical, constricted at both poles, with six distinct +strictures. Seven joints of different lengths, the five abdominal joints +nearly equal, each half as long as the hemispherical, vaulted thorax, and +twice as long as the subspherical, small cephalis. Mouth constricted, with +a short, tubular, hyaline peristome (like an eighth joint without pores), +about one-third as broad as each of the four middle joints. Pores +subregular hexagonal, or irregular polygonal, with thin bars. + +_Dimensions._--Length of the shell (with seven joints) 0.24, greatest +breadth 0.09. Length of the cephalis 0.02, thorax 0.06, each of the four +following joints 0.03, of the last joint 0.04. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +21. _Lithocampe octocola_, n. sp. (Pl. 79, fig. 6). + +Shell smooth, subcylindrical, thick-walled, constricted at both poles, +without distinct, external strictures, but with seven internal septal +rings. Eight joints of different lengths; four joints (the second to the +fifth) being about twice as long as the four others (the first and the +three last). The constricted mouth only one-third as broad as the four +middle joints. Pores small and numerous, subregular, circular. + +_Dimensions._--Length of the shell (with eight joints) 0.19, breadth 0.09. +Length of the second to the fifth joints, each 0.03; length of the four +other joints, each about 0.016. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + +22. _Lithocampe polycola_, n. sp. + +Shell smooth, subcylindrical, constricted at both poles, with twelve to +fifteen distinct strictures. Fourteen to sixteen joints of different +lengths. Cephalis flat, cap-shaped, hyaline, without pores. Thorax nearly +hemispherical, with three transverse rows of small circular pores. Each +following joint (each abdominal joint) only with a single row of small +pores. The constricted mouth of the last joint only one-third as broad as +the middle part of the shell. (Very similar to _Lithomitra eruca_, Pl. 79, +fig. 3.) + +_Dimensions._--Length of the shell (with sixteen joints) 0.3, breadth 0.08. +Length of the cephalis 0.02, thorax 0.06, each of the following joints +0.015, last joint 0.025. + +_Habitat._--Tropical Pacific, Station 224, depth 1850 fathoms. + + + +Genus 651. _Spirocyrtis_,[268] Haeckel, 1881, Prodromus, p. 438. + +_Definition._--#Stichocorida# (vel Stichocyrtida eradiata aperta) with +spirally-arranged constrictions on the shell. Cephalis with a horn. + +The genus _Spirocyrtis_ and the following closely allied genus _Spirocampe_ +differ from the other Stichocorida (and also from nearly all #Cyrtoidea#) +in a very remarkable {1509}character. The annular constrictions of the +multiarticulate shell and the corresponding internal annular septa are here +not separated, and do not lie in parallel, transverse planes (as usually +happens), but they are all or partly connected in the form of an ascending +spiral, so that the joints are not perfectly separated. An irregularity or +asymmetry of growth on the different sides of the shell is probably the +cause of this strange, spiral structure. + + + +Subgenus 1. _Spirocyrtidium_, Haeckel. + +_Definition._--Shell conical, gradually dilating towards the wide open +terminal mouth. + + +1. _Spirocyrtis scalaris_, n. sp. (Pl. 76, fig. 14). + +Shell conical, gradually dilating towards the wide open mouth, with ten to +twelve spiral convolutions, which correspond to the same number of short +and broad chambers or joints, gradually increasing in breadth; all joints +form together a spirally winding staircase. The length or height of the +single joints or stairs is about equal, and each bears four or five +transverse rows of small, square pores. Cephalis flat, cap-shaped, with two +or three short divergent horns. + +_Dimensions._--Length of the shell (with ten joints or turnings) 0.16, +length of each joint (on an average) 0.016; breadth of the third joint +0.04, of the fifth joint 0.07, of the tenth joint 0.1. + +_Habitat._--Central Pacific, Stations 271 to 274, depth 2350 to 2750 +fathoms. + + +2. _Spirocyrtis cornutella_, n. sp. (Pl. 76, fig. 13). + +Shell conical, gradually dilating towards the wide mouth, similar to the +preceding, but differing in the curved axis, and the broader and shorter +joints, each of which bears only two or three transverse rows of square +pores. The turnings of the staircase are not so sharp, nor so distinct, as +in the preceding species. Cephalis with a single short horn. + +_Dimensions._--Length of the shell (with eight joints) 0.1; breadth of the +fourth joint 0.05, of the eighth joint 0.08. + +_Habitat._--Central Pacific, Station 270, depth 2925 fathoms. + + + +Subgenus 2. _Spirocyrtoma_, Haeckel. + +_Definition._--Shell ovate, or nearly spindle-shaped, more or less tapering +towards the narrower, somewhat constricted mouth. + + +3. _Spirocyrtis holospira_, n. sp. (Pl. 76, fig. 16). + +Shell subovate, twice as long as broad, without external strictures, but +with an internal regularly descending spiral septum, which separates seven +to nine broad joints of nearly equal lengths; the {1510}first and second +joints together are conical, and about as long as each of the following +joints. Cephalis small, hemispherical, with a thick pyramidal horn of the +same length. The fifth joint is the broadest, the truncate mouth is +slightly constricted (in the specimen figured it is broken off). Pores +regular, circular, quincuncial. + +_Dimensions._--Length of the shell (with eight joints) 0.2, breadth 0.1; +length of each joint, about 0.03. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +4. _Spirocyrtis hemispira_, n. sp. + +Shell slender, nearly spindle-shaped, three times as long as broad, without +external strictures, but with ten to eleven internal septa. The five or six +upper of these are perfectly separate, complete parallel rings; the five or +six lower are spirally connected. The eleven or twelve joints gradually +taper in length and breadth, from the broadest middle towards the two +constricted ends of the shell. The middle (fifth or sixth) joint is the +broadest, and is three to four times as broad as the constricted mouth. +Cephalis small, hemispherical, with a conical horn of the same length. +Pores regular, circular, hexagonally framed. + +_Dimensions._--Length of the shell (with twelve joints) 0.25, breadth 0.09; +length of the middle joint 0.03. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +5. _Spirocyrtis merospira_, n. sp. (Pl. 76, fig. 15). + +Shell ovate, with six to eight slight strictures, twice as long as broad. +The three or four upper joints are perfectly separated by annular septa, +the three or four lower joints connected by an internal spiral septum. The +spiral line is often more or less irregular or interrupted (as is also the +case in the specimen figured). Mouth rather wide. Pores small, subregular, +circular. A rather variable species. + +_Dimensions._--Length of the shell (with eight joints) 0.2, breadth 0.1. + +_Habitat._--Central Pacific, Stations 270 to 274, depth 2350 to 2925 +fathoms. + + +6. _Spirocyrtis diplospira_, n. sp. (Pl. 76, fig. 17). + +Shell slender, ovate, with seven to eight slight strictures. All eight or +nine joints are connected by an internal double spiral septum, the first +spiral beginning from the ventral side, the second from the dorsal side of +the collar stricture. Length and breadth of the single joints rather +variable and irregular; the broadest joint is commonly the fifth. Mouth +more or less constricted. Pores subregular, circular. This remarkable +species differs from all other #Cyrtoidea# by the double spiral septum of +the joints. + +_Dimensions._--Length of the shell (with eight joints) 0.2, breadth 0.1. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + + +{1511}Genus 652. _Spirocampe_,[269] Haeckel, 1881, Prodromus, p. 438. + +_Definition._--#Stichocorida# (vel Stichocyrtida eradiata aperta) with +spirally arranged constrictions on the shell. Cephalis without horn. + +The genus _Spirocampe_ has the same peculiar spiral structure of the shell +as the preceding _Spirocyrtis_, and differs from it only in the absence of +a cephalic horn. It exhibits, therefore, the same relation to the latter as +the similar _Lithocampe_ bears to _Eucyrtidium_. + + +1. _Spirocampe callispira_, n. sp. (Pl. 76, fig. 11). + +Shell ovate, smooth, with six joints, connected in the form of a complete +winding staircase. All the windings are nearly at equal distances; each +bears one row of large roundish pores, enclosed by two rows of smaller +pores. Cephalis hemispherical, of about the same breadth as the +constricted, short tubular mouth. + +_Dimensions._--Length of the shell (with six joints) 0.15, breadth 0.09; +mouth 0.03 diameter. + +_Habitat._--Central Pacific, Station 270, depth 2925 fathoms. + + +2. _Spirocampe allospira_, n. sp. (Pl. 76, fig. 12). + +Shell subcylindrical, or nearly spindle-shaped, smooth, very thick-walled, +with eight joints alternately longer and shorter, and connected in the form +of an irregular spiral. The distance between the windings is very variable. +Pores small, regular, circular. Cephalis hemispherical, of about the same +size as the short tubular mouth. + +_Dimensions._--Length of the shell (with eight joints) 0.2, breadth 0.08; +mouth 0.03 diameter. + +_Habitat._--Central Pacific, Station 273, depth 2350 fathoms. + + +3. _Spirocampe polyspira_, n. sp. + +Shell cylindrical, rough, with twelve joints nearly equal in length, +connected in the form of a regular, complete spiral. All windings are at +the same distance. Pores regular, circular, three rows on each turning. +Cephalis flat, cap-shaped, half as broad as the slightly constricted, not +tubular mouth. + +_Dimensions._--Length of the shell (with twelve joints) 0.24, breadth 0.07; +mouth 0.05 diameter. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +Subfamily 2. STICHOCAPSIDA, Haeckel, 1881, Prodromus, p. 439. + +_Definition._--#Lithocampida# with the terminal mouth of the shell +fenestrated (vel Stichocyrtida eradiata clausa). + + + +{1512}Genus 653. _Cyrtocapsa_,[270] Haeckel, 1881, Prodromus, p. 439. + +_Definition._--#Stichocapsida# (vel Stichocyrtida eradiata clausa) with an +apical horn on the cephalis, without basal terminal spine. + +The genus _Cyrtocapsa_ and the two following genera represent together the +small subfamily of Stichocapsida, or of those #Cyrtoidea# in which the +many-jointed shell bears no radial appendages, and the terminal mouth is +closed by a lattice-plate. They have been derived from the Stichocorida by +development of such a closing plate. _Cyrtocapsa_ bears an apical horn on +the cephalis, and may be derived therefore directly from _Eucyrtidium_. + + + +Subgenus 1. _Cyrtocapsella_, Haeckel. + +_Definition._--Shell with three annular strictures (or internal septa) and +four distinct joints. + + +1. _Cyrtocapsa tetrapera_, n. sp. (Pl. 78, fig. 5). + +Shell rough, pear-shaped, with three deep strictures. The three first +joints are of equal lengths, and each half as long as the hemispherical +fourth joint. Cephalis subspherical, with an oblique conical horn of the +same length. The third joint is the broadest, three times as broad as long. +Pores regular, circular. + +_Dimensions._--Length of the shell (with four joints) 0.15, breadth 0.09; +length of each of the three first joints 0.03, of the last 0.06. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +2. _Cyrtocapsa compacta_, n. sp. (Pl. 77, fig. 8). + + _Eucyrtidium compactum_, Haeckel, 1878, Atlas, loc. cit. + +Shell rough, pear-shaped, with three slight strictures. The hemispherical +cephalis bears a thick pyramidal spine of the same length, and is half as +long as the second and the third joints, one-third as long as the +hemispherical fourth joint. The third joint is the broadest, three times as +broad as long. Pores subregular, circular. In the centre of the basal pole +is one larger pore, the remnant of the constricted mouth of _Eucyrtidium_. + +_Dimensions._--Length of the shell (with four joints) 0.16, breadth 0.12. +Length of the single joints, _a_ 0.02, _b_ 0.04, _c_ 0.04, _d_ 0.06. + +_Habitat._--Western Tropical Pacific, Station 206, depth 2100 fathoms. + + +{1513}3. _Cyrtocapsa inflata_, n. sp. + +Shell spiny, pear-shaped, with three deep strictures. The inflated third +joint is twice as long as the second and fourth joints, and three times as +long as the hemispherical cephalis, which bears a large conical horn of +three times the length. Fourth joint flat, vaulted, inversely cap-shaped. +The third joint is the broadest, being twice as broad as long. Pores +regular, circular, double-contoured. + +_Dimensions._--Length of the shell 0.14, breadth 0.11. Length of the single +joints, _a_ 0.02, _b_ 0.03, _c_ 0.06, _d_ 0.03. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +4. _Cyrtocapsa pyrum_, n. sp. (Pl. 78, fig. 8). + +Shell thorny, pear-shaped, without external strictures, but with three +internal annular septa. Length of the four joints = 2 : 5 : 6 : 7. The +fourth joint is the broadest, being about twice as broad as long, and +hemispherical. The small subspherical cephalis bears a stout conical horn +of the same length. Pores large, regular, circular. + +_Dimensions._--Length of the shell (with four joints) 0.2, breadth 0.12. +Length of the single joints, _a_ 0.02, _b_ 0.05, _c_ 0.06, _d_ 0.07. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +5. _Cyrtocapsa cornuta_, n. sp. (Pl. 78, fig. 9). + +Shell rough, very thick-walled, nearly pear-shaped, with three annular +strictures; the second of which is very sharp, the first and third slight. +Length of the four joints = 3 : 4 : 5 : 6. The third joint is the broadest, +being about twice as broad as long; the fourth joint is hemispherical. +Cephalis subspherical, with a large, conical, curved horn of twice the +length. Pores regular, circular, hexagonally framed. + +_Dimensions._--Length of the shell (with four joints) 0.18, breadth 0.12. +Length of the single joints, _a_ 0.03, _b_ 0.04, _c_ 0.05, _d_ 0.06. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +6. _Cyrtocapsa diploconus_, n. sp. (Pl. 78, fig. 6). + +Shell rough, doubly conical, with three annular septa. Length of the four +joints = 3 : 4 : 4 : 8. The third joint is the broadest, two and a half +times as broad as long; the fourth is inversely conical, acute. Cephalis +hemispherical, with a pyramidal horn of the same length. Pores irregular, +roundish. + +_Dimensions._--Length of the shell (with four joints) 0.19, breadth 0.1. +Length of the single joints, _a_ 0.03, _b_ 0.04, _c_ 0.04, _d_ 0.08. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + +{1514}7. _Cyrtocapsa fusulus_, n. sp. (Pl. 78, fig. 7). + +Shell smooth, spindle-shaped, with three distinct strictures. Length of the +four joints = 1 : 1 : 4 : 3. The third joint is the broadest, somewhat +longer than broad. The fourth joint is inversely conical. Cephalis +hemispherical, with a coronal of large, ovate pores, and a pyramidal, +sulcate, oblique horn of twice the length. Pores regular, circular. + +_Dimensions._--Length of the shell (with four joints) 0.18, breadth 0.07. +Length of the single joints, _a_ 0.02, _b_ 0.02, _c_ 0.08, _d_ 0.06. + +_Habitat._--South Pacific, Station 295, depth 1500 fathoms. + + + +Subgenus 2. _Cyrtocapsoma_, Haeckel. + +_Definition._--Shell with four or more annular septa, and five or more +joints. + + +8. _Cyrtocapsa incrassata_, Haeckel. + + _Eucyrtidium incrassatum_, Stoehr, 1880, Palaeontogr., vol. xxvi. p. 105, + Taf. iv. fig. 9. + +Shell rough, spindle-shaped, with four annular septa. Length of the five +joints = 2 : 3 : 4 : 4 : 4. The third joint is the broadest, nearly three +times as broad as long. The fourth joint is inversely conical, acute. +Cephalis small, spherical, with two short, conical, divergent horns. Pores +small, regular, circular. + +_Dimensions._--Length of the shell (with five joints) 0.17, breadth 0.11. +Length of the single joints, _a_ 0.015, _b_ 0.035, _c_ 0.04, _d_ 0.04, _e_ +0.04. + +_Habitat._--Fossil in Tertiary rocks of Sicily, Grotte. + + +9. _Cyrtocapsa costata_, n. sp. + +Shell smooth, spindle-shaped, twice as long as broad, with numerous +longitudinal ribs, and four annular septa. Length of the five joints = +1 : 4 : 3 : 2 : 8. The third joint is the broadest. Fourth joint inversely +conical, acute. Cephalis small, hemispherical, with a small conical horn. +Pores regular, circular. + +_Dimensions._--Length of the shell (with five joints) 0.18, breadth 0.09. +Length of the single joints, _a_ 0.01, _b_ 0.04, _c_ 0.03, _d_ 0.02, _e_ +0.08. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +10. _Cyrtocapsa colatractus_, n. sp. + +Shell smooth, spindle-shaped, with eight internal annular septa (without +external stricture). All nine joints are nearly equal in length, the first +somewhat shorter, the last longer. The fourth joint is the broadest, four +times as broad as long. Last joint inversely conical, blunt. Cephalis +subspherical, with a conical horn of the same length. Pores small and +numerous, regular, circular. + +{1515}_Dimensions._--Length of the shell (with nine joints) 0.22, breadth +0.1; length of the cephalis 0.015, of the last joint, 0.03, of each of the +seven other joints, 0.022 to 0.028. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +11. _Cyrtocapsa chrysalidium,_ n. sp. (Pl. 76, fig. 9). + +Shell rough, nearly spindle-shaped, with seven distinct strictures. Length +of the eight joints = 4 : 6 : 11 : 8 : 5 : 5 : 4 : 3. The third and fourth +joints are the broadest. The last joint is small, inversely cap-shaped. +Cephalis subspherical, with an oblique, dentate horn of the same length. +Pores very numerous, subregular, circular. + +_Dimensions._--Length of the shell (with eight joints) 0.23, breadth 0.1. +Length of the single joints, _a_ 0.02, _b_ 0.03, _c_ 0.055, _d_ 0.04, _e_ +0.025, _f_ 0.025, _g_ 0.02, _h_ 0.015. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + + +Genus 654. _Stichocapsa_,[271] Haeckel, 1881, Prodromus, p. 439. + +_Definition._--#Stichocapsida# (vel Stichocyrtida eradiata clausa) without +apical horn, and without basal spine. + +The genus _Stichocapsa_ differs from the preceding _Cyrtocapsa_ in the +absence of an apical horn, and bears therefore to it the same relation as +_Lithocampe_ does to _Eucyrtidium_. It may be derived either from +_Cyrtocapsa_ by loss of the horn, or from _Eucyrtidium_ by closure of the +terminal mouth. + + +1. _Stichocapsa tetracola,_ n. sp. (Pl. 78, fig. 1). + +Shell smooth, spindle-shaped, half as broad as long, with three slight +strictures. Length of the four joints = 3 : 4 : 4 : 11. The fourth joint is +the broadest, inversely conical, with acute basal pole. Pores subregularly +square in the second and third joints, more irregular in the fourth joint. + +_Dimensions._--Length of the shell (with four joints) 0.11. Length of the +single joints, _a_ 0.015, _b_ 0.02, _c_ 0.02, _d_ 0.055; breadth 0.055. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +2. _Stichocapsa quadrigata,_ n. sp. (Pl. 78, fig. 3). + +Shell smooth, pear-shaped, half as broad as long, with three deep +strictures. Length of the four joints = 3 : 8 : 8 : 5. The second joint is +the broadest. The fourth joint is scarcely larger than the hemispherical +cephalis, inversely conical, with blunt basal pole. Pores subregular, +square, in transverse rows, in the second and third joints of equal size, +in the fourth smaller. + +_Dimensions._--Length of the shell (with four joints) 0.12. Length of the +single joints, _a_ 0.015, _b_ 0.04, _e_ 0.04, _d_ 0.025; breadth 0.06. + +_Habitat._--Central Pacific, Station 270, depth 2925 fathoms. + + +{1516}3. _Stichocapsa tricincta,_ n. sp. (Pl. 78, fig. 2). + +Shell smooth, spindle-shaped, twice as long as broad, with three deep +strictures. Length of the four joints = 2 : 5 : 5 : 10. The third joint is +the broadest. Fourth joint inversely conical, with acute basal pole. +Cephalis small, subconical. Pores irregular, roundish, of very different +sizes. + +_Dimensions._--Length of the shell 0.11. Length of the single joints, _a_ +0.01, _b_ 0.025, _e_ 0.025, _d_ 0.05; breadth 0.055. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +4. _Stichocapsa subglobosa,_ n. sp. + +Shell thorny, broad, pear-shaped, nearly spherical, almost as broad as +long, with three internal septal rings. Length of the four joints = +1 : 2 : 7 : 2. Cephalis small, subspherical. Thorax flat, conical. Third +joint very large, inflated, about twice as broad as the second and fourth +joints. The latter is flat, cap-shaped, with rounded basal pole. Pores +regular, circular, hexagonally framed, in the third joint twice as broad as +in the second and fourth joints. + +_Dimensions._--Length of the shell 0.24. Length of the single joints, _a_ +0.02, _b_ 0.04, _c_ 0.14, _d_ 0.04; breadth 0.2. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +5. _Stichocapsa compressa,_ Haeckel. + + _Lithocampe compressa_, Stoehr, 1880, Palaeontogr., vol. xxvi. p. 103, + Taf. iv. fig. 5. + +Shell rough, broad, pear-shaped, almost as broad as long, with three +internal septal rings. Length of the four joints = 1 : 2 : 3 : 2. Cephalis +very small, spherical. Thorax conical. The third joint is the broadest, +strongly inflated. The fourth joint (in the figure of Stoehr broken off) is +in a well preserved specimen inversely hemispherical, with rounded basal +pole. Pores very small, regular, circular. + +_Dimensions._--Length of the shell 0.1. Length of the single joints, _a_ +0.013, _b_ 0.027, _c_ 0.04, _d_ 0.022; breadth 0.08. + +_Habitat._--Fossil in Tertiary rocks of Sicily; Grotte, Caltanisetta. + + +6. _Stichocapsa pyriformis_, n. sp. + +Shell rough, pear-shaped, about twice as long as broad, with three internal +septal rings. Length of the four joints = 2 : 5 : 2 : 9. Cephalis small, +spherical, hyaline. Thorax conical. Third joint very short and broad; the +fourth joint is the broadest, half as long as the shell, with an inversely +hemispherical basal pole. Pores subregular, circular, small and numerous, +larger in the basal third. + +_Dimensions._--Length of the shell 0.18. Length of the single joints, _a_ +0.02, _b_ 0.05, _c_ 0.02, _d_ 0.09; breadth 0.1. + +_Habitat._--Fossil in Barbados. + + +{1517}7. _Stichocapsa monstrosa,_ n. sp. (Pl. 78, fig. 4). + +Shell tuberculate, twice as long as broad, irregular, horn-shaped or +inversely conical, with curved axis, and with three internal septal rings. +Length of the four joints = 2 : 7 : 3 : 4. Cephalis subspherical, with +small, circular pores. The thorax is the broadest joint, half as long as +the shell. The fourth joint is small, inversely conical, with a blunt, +curved, basal pole. Pores irregular, roundish, partly double-contoured. + +_Dimensions._--Length of the shell (with four joints) 0.16. Length of the +single joints, _a_ 0.02, _b_ 0.07, _c_ 0.03, _d_ 0.04; breadth 0.08. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +8. _Stichocapsa pentacola_, n. sp. (Pl. 76, fig. 1). + +Shell smooth, slender, pear-shaped, twice as long as broad, with four sharp +strictures. Length of the five joints = 1 : 1 : 1 : 2 : 3. The three first +joints are nearly equal in length, but increase in breadth. The fifth joint +is the broadest, nearly spherical, with rounded basal pole. Pores +irregular, roundish. + +_Dimensions._--Length of the shell (with five joints) 0.13. Length of the +single joints, _a_ 0.017, _b_ 0.017, _c_ 0.017, _d_ 0.028, _e_ 0.05; +breadth 0.07. + +_Habitat._--Central Pacific, Station 273, depth 2350 fathoms. + + +9. _Stichocapsa hexacola_, n. sp. (Pl. 76, fig. 2). + +Shell rough, slender, pear-shaped, twice as long as broad, with five +internal septal rings. The five first joints are nearly equal in length. +The sixth joint is the broadest, half as long as the shell, with a rounded, +hemispherical basal pole. Pores small and numerous, subregular, circular, +larger in the inflated basal third. + +_Dimensions._--Length of the shell (with six joints) 0.2. Length of each of +the first five joints 0.02, of the sixth joint 0.1; breadth 0.1. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms; also fossil +in Barbados. + + +10. _Stichocapsa compacta_, n. sp. (Pl. 76, fig. 3). + +Shell rough very thick-walled, slender, pear-shaped, twice as long as +broad, without external stricture, but with eight internal septal rings. +The eight first joints, gradually increasing in breadth, are nearly equal +in length. The eighth joint is the broadest, and one-third as long as the +shell, inversely hemispherical. Pores small, circular, in the last joint +larger. + +_Dimensions._--Length of the shell (with nine joints) 0.25. Length of each +of the eight first joints about 0.02, of the ninth joint 0.08; breadth +0.13. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms; also fossil +in Barbados. + + +{1518}11. _Stichocapsa radicula,_ Haeckel. + + _Lithocampe radicula_, Ehrenberg, 1838 (_partim_); Mikrogeol., 1854, Taf. + xxii. fig. 23_b_.? + +Shell smooth, spindle-shaped, decreasing from the broader middle towards +the two rounded poles, with four or five slight strictures. All five or six +joints nearly equal in length, the middle (third and fourth) are the +broadest. Pores subregular, circular. (To this species those forms of +_Lithocampe radicula_, Ehrenberg, must be referred, in which the basal +opening is perfectly closed by lattice-work. The other forms in which the +basal mouth remains open, and which are connected with the former by +transitional forms, constitute the true type of the genus _Lithocampe_ +(page 1503). + +_Dimensions._--Length of the shell (with six joints) 0.12 to 0.15, breadth +0.06 to 0.07. + +_Habitat._--Fossil in Barbados. + + +12. _Stichocapsa subligata_, Haeckel. + + _Lithocampe subligata_, Stoehr, 1880, Palaeontogr., vol. xxvi. p. 102, + Taf. iv. fig. 1. + +Shell rough, subcylindrical, irregular, with seven slight strictures. All +eight joints of slightly different lengths, the third joint is the +broadest; the seventh joint is much broader than the sixth and the eighth +joints. The latter is inversely hemispherical. Cephalis very small, +spherical. Pores regular, circular, very small and numerous. + +_Dimensions._--Length of the shell (with eight joints) 0.24; length of the +single joints (on an average) 0.025 to 0.035, breadth 0.08. + +_Habitat._--Fossil in Tertiary rocks of Sicily (Grotte). + + +13. _Stichocapsa paniscus_, n. sp. (Pl. 76, fig. 4). + +Shell smooth, cylindrical, with a blunt, conical cephalis, and a +hemispherical last joint, without external strictures, but with seven or +eight internal septa. Eight or nine joints nearly equal in length, the +second and the last somewhat longer. Pores circular, of unequal sizes. + +_Dimensions._--Length of the shell (with seven joints) 0.16; length of each +joint (on an average) 0.02 to 0.03, breadth 0.07. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +14. _Stichocapsa cylindrica_, n. sp. + +Shell rough, cylindrical, four times as long as broad, with hemispherical +cephalis and last joint, without external stricture, but with ten or eleven +internal septa. All eleven or twelve joints are nearly equal in length, and +are three times as broad as long. Only the flat cephalis is shorter, and +the vaulted last joint longer than each of the nine or ten other joints. +Pores regular, circular. + +_Dimensions._--Length of the shell (with twelve joints) 0.24; length of +each joint (on an average) 0.02, breadth 0.06. + +_Habitat._--Tropical Atlantic, Station 338, depth 1990 fathoms. + + + +{1519}Genus 655. _Artocapsa_,[272] Haeckel, 1881, Prodromus, p. 438. + +_Definition._--#Stichocapsida# (vel Stichocyrtida eradiata clausa) with an +apical horn on the cephalis, and a basal terminal spine on the last joint. + +The genus _Artocapsa_ differs from _Cyrtocapsa_, its ancestral form, by the +development of a vertical terminal spine, or a bunch of spines, on the base +of the last joint, and bears therefore to it the same relation as +_Rhopalatractus_ does to _Rhopalocanium_. + + +1. _Artocapsa fusiformis_, n. sp. (Pl. 76, fig. 5). + +Shell spindle-shaped, rough, with five slight strictures, decreasing +uniformly from the broader middle towards both poles, with a strong, +pyramidal, terminal spine at each pole. Length of the six joints = +2 : 5 : 3 : 3 : 2 : 5. Cephalis hemispherical, hyaline, without pores, its +horn half as large as the basal spine. Pores small and numerous, +subregular, circular. + +_Dimensions._--Length of the shell (with six joints) 0.2, breadth 0.09. +Length of the single joints, _a_ 0.02, _b_ 0.05, _c_ 0.03, _d_ 0.03, _e_ +0.02, _f_ 0.05. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +2. _Artocapsa spinosa_, n. sp. (Pl. 76, fig. 10). + +Shell spindle-shaped, spiny, with five distinct strictures. Length of the +six joints = 2 : 3 : 2 : 5 : 4 : 4. The fourth joint is the broadest, and +much larger than the five other joints. The first and the last joints are +similar in size and form, hemispherical, armed with some larger, irregular, +conical spines. Pores irregular, roundish, of variable sizes. + +_Dimensions._--Length of the shell (with six joints) 0.2, breadth 0.09. +Length of the single joints, _a_ 0.02, _b_ 0.03, _c_ 0.02, _d_ 0.05, _e_ +0.04, _f_ 0.04. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +3. _Artocapsa infraculeata_, Haeckel. + + _Eucyrtidium infraculeatum_, Stoehr, 1880, Palaeontogr., vol. xxvi. p. + 106, Taf. iv. fig. 13. + +Shell subcylindrical, rough, with five annular septa. Length of the six +joints = 2 : 3 : 4 : 4 : 4 : 3. The third, fourth, and fifth joints are +nearly equal in length and breadth, whilst the second and sixth are +cupola-shaped. The cephalis is very small, subspherical (regarded by Stoehr +as a "large pore"), and bears a short conical horn. The last joint bears a +bunch of basal spines. + +_Dimensions._--Length of the shell (with six joints) 0.2, breadth 0.09. +Length of the cephalis 0.02, second and sixth joints 0.03, third, fourth, +and fifth joints 0.04. + +_Habitat._--Fossil in Tertiary rocks of Sicily; Grotte (Stoehr), +Caltanisetta (Haeckel). + + +{1520}4. _Artocapsa quadricamera_, n. sp. + +Shell spindle-shaped, smooth, with three sharp strictures. Length of the +four joints = 2 : 3 : 4 : 8. The third joint is the broadest. The fourth +joint is inversely conical, nearly as long as the three other joints +together, and bears a strong, conical, basal spine, of half the length. The +cephalis is small, subspherical, and bears a conical horn of the same +length. Pores subregular, circular. + +_Dimensions._--Length of the shell (with four joints) 0.17, breadth 0.08. +Length of the single joints, _a_ 0.02, _b_ 0.03, _c_ 0.04, _d_ 0.08. + +_Habitat._--Fossil in Barbados. + + +5. _Artocapsa armata_, n. sp. + +Shell slender, inversely ovate, spiny, with six deep strictures. Length of +the seven joints = 2 : 4 : 6 : 5 : 4 : 3 : 2. The third joint is the +broadest, inflated, and much larger than the four following, which +gradually decrease in size. The small, hemispherical cephalis bears a stout +pyramidal horn of twice the length. The last hemispherical joint is armed +with a bunch of stout spines, one of which is much the larger, and as long +as the third joint. Pores irregular, roundish. + +_Dimensions._--Length of the shell (with seven joints) 0.26, breadth 0.12. +Length of the single joints, _a_ 0.02, _b_ 0.04, _c_ 0.06, _d_ 0.05, _e_ +0.04, _f_ 0.03, _g_ 0.02. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4575 fathoms. + + +6. _Artocapsa octocamera_, n. sp. + +Shell subcylindrical, smooth, with seven internal annular septa. Five +joints (the third to the seventh) are nearly equal in size, while the +second and eighth are cupola-shaped, somewhat longer. The cephalis is +smaller, with a conical horn of the same length. The last joint bears a +bunch of divergent, conical spines, of different lengths. Pores small, +regular, circular. + +_Dimensions._--Length of the shell (with eight joints) 0.16, breadth 0.08. +Length of the cephalis 0.016, second and eighth joints 0.033, each of the +five other joints 0.022. + +_Habitat._--South Pacific, Station 285, depth 2375 fathoms. + + +7. _Artocapsa elegans_, n. sp. (Pl. 76, fig. 8). + +Shell spindle-shaped, smooth, with eight internal, broad, annular septa. +The second and third joints are the largest, the fourth and fifth of medium +size, while the cephalis and the four last joints are nearly equal in +length, and much shorter. The third joint is the largest. The subspherical +cephalis bears a bristle-shaped horn of the same length, while the last +joint is armed with a bunch of conical spines. Pores small, in the upper +half of the shell regular, hexagonal, in the lower half irregular. + +_Dimensions._--Length of the shell (with nine joints) 0.2, breadth 0.09. +Length of the first and the four last joints, each 0.014; of the fourth and +fifth, each 0.02; of the third 0.04, second 0.05. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + + +{1521}LEGION IV. PHAEODARIA, + +VEL CANNOPYLEA, VEL PANSOLENIA (PLS. 99-128). + + _Phaeodaria_, Haeckel, 1879. + _Tripylea_, Hertwig, 1879. + _Cannopylea_, Haeckel, 1881. + _Pansolenia_, Haeckel, 1878. + +_Definition._--Radiolaria with a double membrane surrounding the central +capsule, which bears on one pole of the main axis a peculiar astropyle, or +a tubular main-opening, in the centre of a circular radiate operculum. +Usually (but not constantly) a pair of small, lateral, accessory openings +(or parapylae) on the opposite pole of the main axis. Extracapsulum +constantly with a phaeodium, or with a voluminous aggregation of peculiar +dark pigment bodies (phaeodella) covering the astropyle of the central +capsule. Skeleton siliceous or silicated, always extracapsular, very rarely +wanting. Fundamental form very variable, originally monaxon, often +dipleuric or bilateral. + +The legion PHAEODARIA, or CANNOPYLEA, in the extent here defined, was +constituted by me in 1878, in my Protistenreich (p. 102) under the name +PANSOLENIA. This name was given on the supposition that the skeleton of +these interesting Radiolaria is always composed of hollow tubules, in +contrast to that of the other Radiolaria, where it is never tubular. But I +was soon convinced that this supposition was erroneous, that in a great +part of the PANSOLENIA the skeleton is not composed of hollow tubules but +of solid bars, and that a constant, very characteristic, and never failing +mark of this group is to be found in the peculiar phaeodium, a voluminous, +constant, extracapsular pigment body. Therefore, in 1879, I changed the +name into PHAEODARIA, and having discovered in the collection of the +Challenger an astonishing number of new and wonderful types of this group, +I described, in a preliminary note on it, four different orders and ten +families with thirty-eight genera (Ueber die Phaeodarien, eine neue Gruppe +kieselschaliger mariner Rhizopoden; in Sitzungsberichte der Jenaischen +Gesellschaft fuer Medicin und Naturwissenschaft. Sitzung vom 12th December +1879). + +In the same year (1879), Richard Hertwig, in his excellent work entitled +Der Organismus der Radiolarien, published the first accurate description of +the intimate structure of the soft body of the PANSOLENIA, and mainly of +their central capsule; and having always observed, in the few +representatives examined by him, three openings in the capsule (one +main-opening and two accessory openings), he called them TRIPYLEA (_loc. +cit._ p. 87), being guided by the erroneous supposition that these three +openings are {1522}constant in all members of the group. But this is by no +means the case. The two accessory openings are completely absent in several +families, whilst in others their number is increased. A constant and very +striking character, however, of all PHAEODARIA, is the peculiar structure +of their tubular main-opening, which I call astropyle, with its radiate +operculum and cannular proboscis. On account of this important and +startling characteristic I proposed in 1881 to call this group CANNOPYLEA. +The two names PHAEODARIA and CANNOPYLEA both express a very striking and +quite constant character of these curious Radiolaria, whilst the two names +PANSOLENIA and TRIPYLEA are applicable only to a part of the whole legion. + +The history of our knowledge of the PHAEODARIA is short, but very +remarkable. Although hundreds of species, many of them cosmopolitan, are +distributed over all oceans and all zones, although their size is in +general much greater than that of the other Radiolaria (usually 1 to 2 mm., +often even 5 to 10 mm. or more), and although their form and structure are +usually striking, nevertheless the PHAEODARIA remained completely unknown +up to the year 1859. During that year I observed the first forms living in +the Gulf of Messina, and described and figured in 1862 in my Monograph five +genera and seven species, viz., (1) _Aulacantha scolymantha_ (p. 263), (2) +_Thalassoplancta cavispicula_ (p. 261, now _Cannobelos cavispicula_), (3) +_Aulosphaera trigonopa_, and _Aulosphaera elegantissima_ (p. 359), (4) +_Spongodictyum trigonizon_ (p. 459, now _Sagoplegma trigonizon_), and (5) +_Coelodendrum ramosissimum_, and _Coelodendrum gracillimum_ (p. 361). I +recognised the structure of the three genera enumerated as 1, 3, and 5, as +so remarkable and so different from that of the other Radiolaria, that I +founded three peculiar families for them, the Aulacanthida, Aulosphaerida, +and Coelodendrida. + +The first note on the numerous remarkable PHAEODARIA discovered by the +Challenger, and mainly on the large-sized inhabitants of the deep-sea, was +published in 1876 by Dr. John Murray, in his Preliminary Reports on Work +done on Board the Challenger (Proc. Roy. Soc., vol. xxiv., read March 16, +1876). He pointed out (_loc. cit._, p. 535), that the tow-nets, sent down +to a great depth (according to a new plan, adopted in April 1875) brought +up on every occasion a great many new and peculiar Rhizopods, which had +never been observed in the nets used near the surface. "The shells of all +have an exceedingly beautiful tracery, a fenestrated appearance often, +which a closer examination shows to be caused by pit-like depressions. Some +have only one, others have several openings, through which the sarcode +flows. The sarcode of all these deep-sea Rhizopods has many large +black-brown pigment-cells. At times they come up with a good deal of the +sarcode outside of the shell; and two specimens have been seen to throw out +elongated pseudopodia" (_loc. cit._, p. 536). Dr. John Murray distinguished +at that time not less than fifty species of these interesting deep-sea +Rhizopods and called them provisionally Challengerida; a term which we +retain here for the largest and most characteristic family. He gave at the +same time, in an accompanying plate (xxiv.), six {1523}figures of new +PHAEODARIA, the names of which (as found by me in 1879 in the corresponding +preparations) are the following; (1) _Challengeria naresii_, (2) +_Challengeria aldrichii_, (3) _Bivalva compressa_ (now = _Conchopsis +compressa_), (4) _Tuscarora belknapii_, (5) _Challengeria circopora_ (now = +_Circoporus sexfurcus_), and (6) _Haeckeliana porcellana_. A great number +of these Challengerida (twenty species) were afterwards figured by Dr. John +Murray in the Narrative of the Cruise of H.M.S. Challenger, 1885, vol. i. +part 1, p. 226, Pl. A; viz., fourteen species of _Challengeria_ and six +species of _Tuscarora_. + +The most important advance in the knowledge which we had of the peculiar +organisation of the PHAEODARIA, was made by the accurate description which +Richard Hertwig published, in 1879, of the intimate structure of their +central capsule, and mainly of its peculiar openings. He examined living at +Messina the following three forms, described in my Monograph; (1) +_Aulacantha scolymantha_, (2) _Aulosphaera elegantissima_, and (3) +_Coelodendrum ramosissimum_. Besides, he described an interesting new +genus, _Coelacantha anchorata_; and another new form, which he placed in +the Aulosphaerida, as _Aulosphaera gracilis_, but which really was a new +genus of Sagosphaerida, here described as _Sagoscena gracilis_. Finally, +Hertwig first discovered that the peculiar bodies, described by Ehrenberg +as _Dictyocha_ and placed by him in the _Diatomea_ (_Polygastrica_), were +the isolated pieces of the skeleton of a true _Phaeodarium_, and that they +were scattered loosely in great numbers over the surface of the +jelly-sphere, just as are the hollow spicula of _Thalassoplancta_ or +_Cannobelos_. + +The six species mentioned, of which Hertwig gave a very accurate +description and very instructive figures, belong to six different genera, +and these represent six different families of PHAEODARIA, viz.; +Aulacanthida, Aulosphaerida, Coelodendrida, Cannosphaerida, Sagosphaerida +and Cannorrhaphida. He found that all these six forms, in spite of great +differences in the form and structure of their skeleton, were identical in +the structure of the central capsule; and since he observed constantly +three openings in its double wall (a large main-opening on the oral pole, +and a pair of lateral accessory openings on the aboral pole of its main +axis) he called them TRIPYLEA (_loc. cit._, p. 87, 94). But he also pointed +out the remarkable shape of their voluminous extracapsular body, and +especially the characteristic position, size, colour and composition of the +large pigment body, which I had called the phaeodium. + +The accurate description of the gigantic and elegant skeleton of a new +_Phaeodarium_, surpassing all other known Radiolaria in its extraordinary +size (15 mm.), was published in 1882 by O. Buetschli (in Zeitschr. f. wiss. +Zool., vol. xxxvi. p. 486, Taf. xxxi.). He called it _Coelothamnus +davidoffii_, in honour of its discoverer, who had found it floating on the +surface of the Gulf of Villafranca, near Nice. He placed it among the +Coelodendrida; it belongs, however, to that part of this group which +possesses a nasal tube, and which I afterwards separated under the name +Coelographida. + +{1524}The total number of PHAEODARIA, hitherto described and illustrated by +figures, amounts therefore to seventeen species, viz., the seven species +first described by myself (in 1862); the six new species figured by Dr. +John Murray (in 1876); the three new species discovered by Hertwig (in +1879) and the single species last-mentioned described by Buetschli (in +1882). The rich collection of the Challenger has added to this small number +such an astonishing wealth of new and remarkable forms, that I can describe +in the following system of PHAEODARIA not less than eighty-four genera and +four hundred and sixty-five species. These belong to fifteen different +families and four different orders. But this great number is probably only +a small part of the numerous interesting PHAEODARIA, which are abundantly +distributed over all the oceans; those (_e.g._) of the Indian and of the +Arctic Oceans are almost unknown. + +The great majority of these wonderful PHAEODARIA are inhabitants of the +deep-sea, mainly of the southern hemisphere, and are so common in many +stations explored by the Challenger, that its collection contains many +thousands (or rather hundreds of thousands) of well-preserved specimens. A +smaller part of the legion is found on the surface, widely distributed over +all oceans; some of these are very common (as, _e.g._, _Aulacantha_, +_Aulosphaera_, _Sagosphaera_, _Coelodendrum_, _Castanella_, &c.) and it is +difficult to explain how they could entirely escape the eyes of all former +observers. + +The three general characters which distinguish the PHAEODARIA easily and +constantly from all the other Radiolaria are the following:--(1) the double +membrane, a thick outer and a thin inner envelope, of the big central +capsule; (2) its typical main-opening or astropyle, placed on the oral pole +of the main axis, and distinguished by a peculiar radiate operculum, with +tubular proboscis; (3) the phaeodium, or the peculiar voluminous +pigment-body, which constantly lies in the oral half of the calymma, +surrounds the oral part of the central capsule, and is composed of numerous +phaeodella, or singular pigment-granules of green, olive, brown or black +colour. + +Besides these three general and never failing marks of the PHAEODARIA, the +majority of this legion (but by no means all) possess the three following +peculiarities; (1) two parapylae or accessory openings of the central +capsule, placed laterally (at the right and left) on the aboral pole of the +main axis (wanting in the Challengerida, Medusettida, Castanellida, and +perhaps in some other families); (2) a characteristic skeleton which is +always extracapsular, wanting only in the Phaeodinida, incomplete in the +Cannorrhaphida and Aulacanthida, but perfectly developed and of very +various shapes in the twelve other families; usually this silicated +skeleton is composed of hollow tubules, which are filled up by jelly +(PANSOLENIA); but in some families it is composed of ordinary solid +network, not different from that of the other Radiolaria, _e.g._, +especially in the Castanellida and Sagosphaerida; (3) an extraordinary size +of the body, as well of the central capsule and its nucleus, as of the +extracapsular skeleton; the majority of PHAEODARIA have a diameter of 1 to +2 mm., and are therefore from ten to twenty times as large as the +{1525}majority of the other Radiolaria; in some gigantic forms the diameter +of the unicellular body reaches 20 or even 30 mm. + +_The Central Capsule_ of the PHAEODARIA is the most important part of their +body and preserves in all families of this legion the same essential +structure, and nearly the same form, in striking contrast to the +extraordinary variety and complication of the skeleton. As already +mentioned, it differs from the central capsule of all the other Radiolaria +in two most important peculiarities; firstly, the double membrane of the +spheroidal capsule, and secondly, the singular structure of its constant +main-opening, the astropyle. A third constant character is the considerable +size of the enclosed nucleus, the diameter of which usually equals about +half of that of the capsule itself. + +The diameter of the capsule is, in the majority of PHAEODARIA, 0.1 to 0.2 +mm., often also 0.3 to 0.4, rarely more than 0.5, or less than 0.05 mm. + +The position of the central capsule is somewhat different in the four +orders into which we have divided the PHAEODARIA. It lies in the centre of +the spherical, concentric calymma in all the #Phaeocystina#, or in those +PHAEODARIA which possess no complete lattice-shell--Phaeodinida, +Cannorrhaphida, and Aulacanthida (Pls. 101-105). The #Phaeosphaeria# +(comprising the Orosphaerida, Sagosphaerida, Aulosphaerida, and +Cannosphaerida, Pls. 106-112) all possess a very big, usually spherical +lattice-shell, and here the central capsule is much smaller than the latter +and lies in its centre. Another position is constantly occupied by the +central capsule in all #Phaeogromia# (Pls. 99, 100, 113-120; the families +Challengerida, Medusettida, Castanellida, Circoporida, Tuscarorida), which +have a peculiar mouth on the lattice-shell, placed on the oral pole of its +main axis; the central capsule lies in the opposite aboral half of the +shell cavity. The #Phaeoconchia# finally (Pls. 121-128, the families +Concharida, Coelodendrida, and Coelographida) all possess a bivalved shell, +and the capsule is here enclosed between the two valves of the shell. + +The form of the central capsule is constantly spheroidal, slightly +depressed in the direction of the main axis, and therefore comparable to +the spheroidal form of our globe. The depression is generally very slight, +so that the proportion of the minor vertical main axis to the major +horizontal or equatorial axis is about 4 : 5 or 5 : 6, often even 8 : 9 or +less; but sometimes the proportion becomes 3 : 4, or even 2 : 3, so that +the capsule becomes nearly lenticular; very rarely its form becomes almost +perfectly spherical (Pl. 101, fig. 1). The main axis stands always +vertically, and is distinctly marked by the peculiar shape of the +astropyle, placed on its oral pole. Usually this pole, in the living and +freely floating PHAEODARIA seems to be the lower pole, directed downwards +(as also in the NASSELLARIA); but in some families it seems to be inversely +directed upwards, as in the Challengerida and Tuscarorida, (Pls. 99, 100). + +The two _membranes of the central capsule_ possess in all PHAEODARIA a very +different shape, and were in all preparations which I could accurately +examine (some hundreds {1526}belonging to all families) separated by a +clear, rather wide interval, filled up either by a colourless fluid or by a +structureless jelly (Pl. 103, fig. 1; Pl. 123, figs. 8, 9, &c.). They are +in direct connection only at the openings. In the living PHAEODARIA, +however, their distance is very small, or they are in immediate contact +without any interval (Pl. 101, fig. 10; Pl. 102, fig. 1). According to the +observations of Hertwig, the two membranes are always in close contact, and +without interspace, in the living PHAEODARIA; and the space between them is +an artificial product due to the influence of the preserving fluid or of +certain chemical agents. In every case it is very easy to separate both +membranes completely, except at the openings, where they are in direct +connection. We distinguish both membranes shortly as ectocapsa and +endocapsa. + +The ectocapsa, or the outer membrane of the central capsule, is rather firm +and durable, double-contoured, elastic and difficult to destroy. Its +physical and chemical qualities seem to approach those of chitin. It +becomes, however, stained red by carmine, and yellow by nitric acid. +Usually it appears structureless and refracts the light strongly. In a few +cases, however, it exhibits, when examined by strong lenses, a fine +punctation; and in some Aulacanthida (especially in some big forms of +_Aulographis_ and _Aulospathis_) the entire ectocapsa was densely covered +with peculiar curved, or S-shaped dark corpuscles (Pl. 114, fig. 13). They +were all of the same length, about 0.01, and seemed to lie on its inner +face. + +The endocapsa, or the inner membrane of the central capsule, is much +thinner than the outer, with which it is in immediate connection only at +the openings. It encloses the entire contents of the capsule, and becomes +very distinct, as soon as the latter are dissolved by chemical agents, or +stained by carmine. In the majority of well-preserved preparations it is +irregularly plicated, and resembles a thin, but firm, crumpled paper. +Isolated pieces of the endocapsa are completely structureless, but exhibit +also a considerable resistance, in spite of their minute thickness. + +The openings of the central capsule exhibit in the PHAEODARIA a greater +variety than their discoverer, R. Hertwig, supposed. The majority of the +legion, certainly, possess the three openings described by him, and are +therefore true TRIPYLEA. Some families, however, have only one opening, the +astropyle, which is generally present (Challengerida, Medusettida, +Castanellida, and _Phaeocolla_ among the Phaeodinida, Pl. 101, fig. 1). In +some other families there is a variable number of accessory openings or +parapylae, one, three, or more, _e.g._, especially in the Circoporida and +Tuscarorida. The former may be called Astropylea, the latter Sporopylea. +Thus only a single opening to the central capsule is constant in all +PHAEODARIA without exception, and that is the astropyle, or the large +main-opening with its peculiar structure. + +The astropyle, or the single constant main-opening of the central capsule, +is distinguished by a very remarkable structure, and is sufficient of +itself to separate the {1527}PHAEODARIA from all the other Radiolaria, and +from the other Rhizopoda in general. It is always placed on the oral pole +of the main axis, forming here a peculiar cap-shaped or flatly conical +elevation, the centre of which is prolonged into a short, cylindrical +tubule; we call the latter shortly a proboscis, and the former an +operculum. To understand better the different forms which these important +parts assume in the different families, compare Pl. 101, figs. 1-6; Pl. +102, fig. 1; Pl. 103, fig. 1; Pl. 104, figs. 1-3; Pl. 111, fig. 2; Pl. 123, +figs. 1-9; Pl. 127, figs. 4-6; Pl. 128, fig. 2, &c. Compare also the first +very accurate figures which R. Hertwig has given in 1879 (_loc. cit._) in +his Taf. x. + +The operculum of the astropyle, the most important part of this main +opening ("der Oeffnungshof der Hauptoeffnung," in the description of +Hertwig), is a circular convex plate, always more strongly vaulted than the +surrounding part of the capsule membrane, and is sharply separated from it +by a circular, often thickened and double-contoured margin. The operculum +covers the main-opening like the lid of a tea-kettle, and the proboscis +arising from its centre is comparable to the handle of that lid. The +diameter of the circular operculum is usually about half as long (rarely as +long) as the radius of the central capsule, therefore in the majority of +PHAEODARIA 0.03 to 0.06, sometimes 0.1 and more. Its form is sometimes more +conical, sometimes more like a mamma. Its height is usually about equal to +half its diameter. It always exhibits a very distinct radial striation, +produced by numerous prominent radial ribs, which arise in the centre and +end at the circular sharply truncated margin. The usual number of these +radial ribs may be, in the operculum of smaller capsules, from thirty to +fifty, in those of medium size from sixty to ninety, and in the largest two +hundred to three hundred or more. Usually the ribs are simple (Pl. 101, +figs. 1, 2, 6, 10; Pl. 127, figs. 4-6; also in all figures given by +Hertwig); but sometimes, mainly in the biggest Aulacanthida, they are +distinctly branched in a centrifugal direction (Pl. 114, fig. 13; Pl. 115, +fig. 3). Hertwig is of the opinion that the radial ribs are thickened +ridges of the endocapsa ("leistenartige Verdickungen der inneren Membran"), +and that the ectocapsa covering it is structureless (compare his figs. 1 +and 1_a_, in Taf. x.). But I am convinced now, by numerous experiments and +observations, that the radiate operculum is a part of the outer, not of the +inner membrane. That part of the latter which lies immediately beyond the +former, and which may be called the "inner operculum," also exhibits +usually a fine radial striation; but this is probably only the cast of the +stronger and much more prominent radial ribbing of the "outer operculum" +belonging to the ectocapsa. The latter exhibits a large circular opening +with thickened margin, when the radiate operculum is taken from it. The +operculum becomes stained intensely red by carmine, yellow by nitric acid, +corresponding to the ectocapsa, the main-opening of which is closed by it. + +The proboscis, or the cylindrical tubule, which arises in the centre of the +{1528}operculum, is often rather short, and bears the same relation to it +as the nipple does to the human breast (Pl. 104, fig. 2). But usually it is +more or less prolonged and often about as long as the radius of the +capsule, rarely nearly as long as its diameter (Pl. 101, fig. 1). Its form +is usually a slender cylinder, sometimes somewhat conical and tapering +towards the distal end. It is more or less curved or S-shaped in the +majority of preparations (Pl. 115, fig. 3; Pl. 127, fig. 6, &c.). Its thin +wall is a direct prolongation of the outer membrane of the capsule, +therefore it appears as a direct apophysis of the operculum, when this is +detached from the latter. The opening at the distal end of the proboscis, +through which the endosarc is thrown out, is circular. + +The parapylae, or the accessory openings of the central capsule, exhibit in +all PHAEODARIA the same form and structure, but vary in number and +disposition. They are recognised with difficulty in the smaller species, +since they are always of small size, and may be easily overlooked. They +seem to be completely wanting in the following families:--Challengerida +(Pl. 99), Medusettida (Pls. 118-120), Castanellida (Pl. 113), and in single +genera of other families, as in _Phaeocolla_ (Pl. 101, fig. 1). The +majority of PHAEODARIA seem to possess the two lateral parapylae, first +described by Hertwig, placed at a variable distance on each side of the +aboral pole, to the right and left (Pl. 101, figs. 2, 6, 10; Pl. 103, fig. +1_a_; Pl. 104, figs. 1, 2_a_; Pl. 123, figs. 1, 8_a_ &c.). The horizontal +axis, on which the two parapylae lie, is the the frontal or lateral axis; +and the plane, which passes through the three openings of these "Tripylea," +is the frontal or lateral plane. The number of the parapylae seems to be +variable in the two families, Circoporida and Tuscarorida, which also +differ from the other PHAEODARIA in the peculiar (porcellanous) structure +of their shell-wall. The number seems to vary even in the single species of +one genus; and the following cases may be found: (A) a single parapyle, +placed on the aboral pole of the main axis and directly opposed to the +astropyle (on the oral pole), as in _Tuscaridium_ (Pl. 100, fig. 8); (B) +three equidistant parapylae, one of which is placed in the sagittal plane, +and the two others one on each side of it, to the right and left, is in +_Tuscarora_ (Pl. 100, figs. 1-6); the three parapylae seem to correspond +here to the three long feet, or the tubular aboral apophyses of the shell, +which are arranged in a similar manner to the three cortinar feet of the +NASSELLARIA; (C) four equidistant parapylae, placed in pairs on the poles +of the diagonal axes of a horizontal plane, as in _Tuscarora_ (Pl. 100, +fig. 7); they seem here to correspond to the four crossed aboral feet; (D) +six to eight or more parapylae probably in the different genera of +Circoporida (Pls. 114-117); perhaps each radial tube, which is surrounded +on its base by a circle of pores, here corresponds to a separate parapyle. +The number of well-preserved central capsules belonging to the two latter +families, however, which I could examine was relatively small and their +examination very difficult; therefore these numbers are not stated with +satisfactory certainty and require a further more accurate examination. +{1529}The minute structure of the parapylae (or "Neben-Oeffnungen") has +been described already very accurately by Hertwig (_loc. cit._, p. 95, Taf. +x. figs. 1-11_b_). The two membranes of the capsule are in direct and +immediate connection on each parapyle. The strong outer membrane arises in +the form of a ring or of a short cylindrical tubule (collare paraboscidis +or "Oeffnungshals"), is then reflected inwards, and connected at the bottom +of the cylindrical cavity with the delicate inner membrane. From this +connective ring arises a short conical or cylindrical tubule, which we call +shortly the "paraboscis." According to Hertwig (who calls it +"Oeffnungskegel") the paraboscis is a direct prolongation of the inner +membrane only. My own observations have led me to the opinion, that the +paraboscis of each parapyle is a direct prolongation of the outer membrane +(similarly to the larger proboscis of the astropyle), and that the basal +connective ring is, therefore, the inner opening of the paraboscis, through +which the entosarc enters, being protruded through its outer circular +opening. Usually the paraboscis of each parapyle is only a short cylinder, +arising by a conical base; but sometimes, especially in some Aulosphaerida +and Sagosphaerida, it is prolonged into a slender tubule, nearly as long as +the radius of the central capsule. It has been already figured by Hertwig +(_loc. cit._, Taf. x. figs. 6-8). It seems, therefore, that the paraboscis +of the accessory openings is developed in a way similar to the proboscis of +the main-opening, and that the chief difference between the two is +indicated by the large radiate operculum of the latter. + +The cavity of the endocapsa, or the spheroidal space enclosed by the inner +membrane of the central capsule, is filled up in its central part by the +big nucleus, in its peripheral part by the endoplasm, or by the internal +protoplasm, which is in communication with the outer or extracapsular +protoplasm by the openings of that capsule. The endoplasm, or the +intracapsular sarcode, is rather opaque, finely granulated, and usually +filled up by numerous small clear spherules of equal size, which are more +or less regularly arranged and equidistant. These spherules have usually a +diameter of 0.01 to 0.015, rarely more than 0.02 or less than 0.005 mm.; +their size is generally equal in each capsule. They have been already +described and figured in my Monograph, as "wasserhelle kugelige Blaeschen," +and are probably vacuoles or small vesicles filled up by jelly or by a +clear fluid. Usually each vesicle contains a small dark granule of fat, or +a group of such granules connected together; and in these Hertwig observed +a vibrating molecular motion. The central capsule of many PHAEODARIA +contains, besides the vacuoles, often granules of pigment (usually red or +yellow) and sometimes numerous groups of small crystals, placed mainly +beyond the operculum of the astropyle (Pl. 127, figs. 4-7). The outer layer +of the endoplasm, placed immediately beyond the endocapsa, often exhibits a +fine striation, as if composed of delicate fibrillae. This fibrillar +striation is usually most distinct on the base of the openings, where also +the endoplasm becomes stained very intensely by carmine. The astropyle as +well as {1530}the parapylae often exhibit here, when observed from the +face, a distinct radial striation (compare Hertwig, _loc. cit._, p. 98, +Taf. x. figs. 6-14) Perhaps the radiate shape of the operculum is only +produced by radial folds of the endocapsa placed beyond it, and these folds +may be in turn the product of the radial fibrillae, which are prominent +beyond the astropyle. On the other hand, these fibrillae may be compared to +the muscular fibrillae or "myophane filaments" in the ectosarc of the +Infusoria, and may perhaps effect by their contraction a dilatation of the +openings of the capsule. + +The nucleus of the PHAEODARIA is always very large, usually about half or +two thirds as broad as the central capsule and placed either in its centre, +or sometimes nearer to one pole of the main axis, which is common to the +capsule and its nucleus. Therefore the diameter of the latter is usually +half or even two thirds of that of the capsule, and may be in the majority +0.05 to 0.15, often 0.2 to 0.3, rarely more than 0.4 or less than 0.01 mm. +The form of the nucleus is rarely spherical, usually spheroidal, and it is +more depressed in the direction of the main axis than the capsule itself. +In my Monograph, where I gave the first description of it, I called it +"Binnenblaeschen." The membrane of the vesicular nucleus is thin but rather +firm, and contains a rather clear, finely granulated substance, in which +numerous nucleoli are usually scattered. (Compare Pl. 101, figs. 1-10; Pl. +102-104; Pl. 123; Pl.127, &c.; the nucleus is marked by _n_, the nucleoli +by _l_.) + +The nucleoli are very different in respect to their form, size, number and +arrangement. Since these differences are very great even in different +specimens of a single species (as, _e.g._, in the common cosmopolitan +_Aulacantha scolymantha_, _Aulosphaera trigonopa_, _Coelodendrum +ramosissimum_, &c.), it is probable that they represent different stages of +development and multiplication, and that the smallest fragments of the +nucleoli, or the final results of their repeated division, become the +nuclei of the flagellate spores, which are developed in the PHAEODARIA just +as in the other Radiolaria. In the majority of nuclei examined, the number +of the enclosed nucleoli proved to be very great, fifty to eighty or more, +often some hundreds, the greater their number the smaller their size. Their +form is usually irregular, roundish, or even amoeboid--probably the result +of amoebiform motions (Pl. 101, fig. 1). Sometimes the nucleoli were +regularly spherical, equidistant, and connected apparently by a delicate +network (Pl. 101, fig. 2). (Compare Pl. 102-104, 111, 123, and also Taf. x. +of Hertwig, _loc. cit._). + +The calymma, or the extracapsular jelly-veil, is in the PHAEODARIA always +well developed and usually much larger than the enclosed central capsule. +The entire volume of the calymma may be three to six times as great as that +of the capsule in the majority of this legion; but in the large +Aulacanthida, Aulosphaerida, Coelodendrida, Coelographida, &c., the volume +of the former is twenty to fifty as great as that of the latter, or even +more. The jelly substance is rather firm and consistent, clear, +structureless, and becomes more or less intensely stained by carmine. In +the {1531}larger forms it is often filled by numerous large alveoles, which +are usually absent in the smaller forms. These extracapsular alveoles are +most strongly developed in the calymma of the #Phaeocystina#, or the +PHAEODARIA with incomplete skeleton, embracing the three families +Phaeodinida, Cannorrhaphida and Aulacanthida (Pls. 101-104). Usually the +calymma is here very voluminous and entirely filled up by large alveoles, +which are either spherical, irregularly roundish, or polyhedral by mutual +compression. These alveoles or vacuoles have no peculiar wall, but are only +cavities in the homogeneous substance of the jelly, and are filled by a +clear aqueous fluid. Between these the network of the anastomosing +pseudopodia is expanded. They exhibit, therefore, the same shape, as was +first observed in _Thalassicolla_ and in the #Polycyttaria# (Collozoida, +Sphaerozoida and Collosphaerida). + +The relation of the calymma to the skeleton is in the PHAEODARIA of the +same importance as in the other Radiolaria, and we may also here +distinguish a primary and a secondary calymma. The primary calymma is that +on the surface of which at a certain period of life (in the "shell-building +period") the fenestrated shell is secreted in the majority of PHAEODARIA. +The secondary calymma, however, is formed after this period, and envelops +the shell itself as well as its apophyses externally. Usually the entire +skeleton seems to be enveloped by the secondary calymma. + +The parts of the extracapsular body, which are enclosed in the gelatinous +calymma possess a peculiar importance in the PHAEODARIA; these are firstly +the sarcomatrix and the pseudopodia arising from it, and secondly the +phaeodium. The sarcomatrix, or the layer of extracapsular sarcode +(ectoplasm), which immediately surrounds the central capsule is very thick +and more strongly developed in all PHAEODARIA than in all other Radiolaria. +Its extraordinary size has been already mentioned by Hertwig (1879, _loc. +cit._, p. 99). It is in direct connection with the intracapsular sarcode +(or the endoplasm) only by the openings of the central capsule, and mainly +by the astropyle. Very numerous radial pseudopodia arise everywhere from +the sarcomatrix and run to the surface of the calymma, usually forming a +rich network in it by means of numerous branches and anastomoses (compare +Pl. 101-104). On the surface of the calymma the meshes of this network are +very numerous, and there arise from its nodal points the terminal +pseudopodia, which float freely in the surrounding water. The metamorphoses +of this network of sarcode, the perpetual changes in the number and size of +its meshes, and the movements of the sarcode streams as well as of the +small granules running in it, are always very manifest in the PHAEODARIA +and in the big forms of this legion (mainly in the Aulacanthida) they are +better observed than in the majority of other Radiolaria. In many +PHAEODARIA (and perhaps in all) a part of the pseudopodia seems to have +undergone a local differentiation, for special physiological purposes; and +Hertwig has described a peculiar conical contractile body, which arises in +_Coelodendrum_ between the two parapylae (_loc. cit._, p. 100, fig. 3). +Further examination {1532}of these interesting organs in living PHAEODARIA +is required. Usually the sarcode, issuing from the openings of the capsule, +forms a stronger cylinder, with peculiar movements. + +The phaeodium, or the peculiar dark extracapsular pigment-body of the +PHAEODARIA, is one of the most important and most characteristic parts of +their organisation, and has induced me to derive their name from it; it is +not less typical for the whole legion, than the astropyle with its radiate +operculum and the proboscis; and both these important parts are always in +direct topographical and physiological connection. Whilst I have missed the +phaeodium in no _Phaeodarium_ in which the soft body was well preserved, I +have not found it in any other Radiolaria; for the similar extracapsular +pigment bodies, which are found in some species of _Thalassicolla_ and some +other #Sphaerellaria#, have a composition and signification different from +that of the phaeodium--an exclusive peculiarity of the PHAEODARIA. + +The typical importance of the phaeodium for all members of this legion is +proved by the following five facts:--(1) its constant presence in all +PHAEODARIA; (2) its constant excentric position in the oral half of the +calymma; (3) its constant relation to the astropyle, the operculum and the +proboscis of which is always surrounded by it; (4) its constant +considerable size, its volume being usually greater than that of the +central capsule, the aboral half of which is covered by it; (5) its +constant colour and morphological as well as chemical composition. These +five facts together demonstrate by their absolute constancy the high +morphological and physiological importance of the phaeodium for this +peculiar subclass of Radiolaria, although its true nature is difficult to +make out, and its main function is not yet sufficiently known. + +The first remarks that have been made on the phaeodium were published in +1862 in my Monograph, where I noticed the peculiar dark brown extracapsular +pigment body and its excentric position covering only one-half of the +central capsule, in _Aulacantha_ (p. 263, Taf. ii. figs. 1, 2), in +_Thalassoplancta_ (p. 262, Taf. iii. fig. 10), and in _Coelodendrum_ (p. +361, Taf. xxxii. fig. 1). Its general presence and peculiar composition +were first recognised by Dr. John Murray, who had, during the Challenger +Expedition, the first opportunity of examining many big living PHAEODARIA +brought up from great depths. He gives in his first Report (1876, _loc. +cit._, p. 536), the following important notice:--"The sarcode of all these +deep-sea Rhizopods has many large black-brown pigment-cells. Small +bioplasts are scattered through the sarcode. These collect into +capsular-like clumps when the animal is at rest, and are quickly coloured +by carmine." In 1877 Dr. John Murray sent me the wonderful collection of +PHAEODARIA brought home by the Challenger, and I had now the best +opportunity for examining the phaeodium in hundreds of well-preserved +specimens. Supported by these extensive observations, I gave, in 1879, in a +preliminary paper,[273] a fuller description of the {1533}phaeodium, and of +the phaeodella (or the peculiar dark pigment-granules composing it). At the +same time R. Hertwig published his observations on the big living TRIPYLEA +examined by him at Messina, and pointed out particularly that the constant +presence, composition, and arrangement of this excentric extracapsular +pigment-body was most characteristic, and sufficient in itself to +distinguish this group from all the other Radiolaria (1879, _loc. cit._, p. +99). + +The most striking peculiarity of the phaeodium, and the most important on +account of its absolute constancy, is its excentric position, covering only +the oral hemisphere of the central capsule, and wholly or partly wanting on +the aboral hemisphere. This constant topographical relation to the capsule +never fails, and may be always observed at the first glance, when the body +is seen from the side (the main axis of the capsule being perpendicular to +the axis of the eye of the observer), (compare Pl. 101, figs. 6, 10; Pl. +102, fig. 1; Pl. 103, fig. 1, &c.). The phaeodium envelops, therefore, the +oral half of the capsule completely, and especially the astropyle in its +centre; hence, the radiate operculum and the proboscis arising from the +latter cannot be seen usually before the former is removed. The general +form of the entire phaeodium, in consequence of this excentric position, is +concavo-convex (or crescentic in longitudinal section), its concave face +embracing the oral or anterior face of the capsule, and its convex face +being turned to the surface of the calymma. + +The topographical relation of the phaeodium to the surrounding shell is +also very characteristic in the suborder #Phaeogromia#, or in those +PHAEODARIA which possess a peculiar shell-mouth placed on the oral pole of +its main axis. Here the capsule is always placed in the aboral half of the +shell-cavity, the phaeodium in its oral half, separating the astropyle from +the mouth of the shell, both of which lie in the main axis; as in the +Challengerida (Pl. 99), Tuscarorida (Pl. 100), Castanellida (Pl. 113), +Circoporida (Pl. 115), and Medusettida (Pl. 118-120). In this suborder (the +#Phaeogromia#), the volume of the phaeodium may be, on an average, about as +great as that of the central capsule, whilst in the majority of other +PHAEODARIA it is much greater than the latter. + +A similar topographical relation between the phaeodium and the enclosing +shell, as in the #Phaeogromia#, also exists in the suborder #Phaeoconchia#, +or in those PHAEODARIA, which are distinguished from all the others by the +possession of a bivalved shell (Pl. 121-128). The two valves of this +curious shell, which resembles that of the Brachiopoda, are dorsal and +ventral, and the tripylean central capsule is always so placed between them +that its two lateral parapylae (right and left) lie in the frontal plane of +the shell, where a large frontal fissure opens between the opposed margins +of the two hemispherical or cap-shaped valves. The phaeodium is also placed +here on the oral half of the capsule and surrounds its astropyle; but it +exhibits some differences in the three families of #Phaeoconchia#. + +{1534}The Concharida, the bivalved shell of which is simple, and without +tubular apophyses (Pl. 123-125), possess a relatively small central +capsule, which usually fills up only the third or fourth part of the +shell-cavity. This is the aboral or posterior part, on the apex of which +both valves are united by a ligament in some Concharida (Pl. 123, figs. 8, +9). The oral or anterior part of the shell-cavity (usually two-thirds or +more) is filled up by the phaeodium, and this is usually bifid, being +divided by a frontal constriction into two wings or lobes; the dorsal wing +is hidden in the upper valve of the shell, the ventral wing in the lower +valve; both wings are usually united only by a small central bridge, and +this bridge of the phaeodium is pierced in its centre by the proboscis of +the astropyle (Pl. 124, figs. 6, 10; Pl. 123, figs. 8, 9). + +The Coelodendrida have a different shape (Pl. 121). Their bivalved shell is +relatively small and tiny, and bears on the two poles of the sagittal axis +two conical apophyses or galeae, from each of which three or four very +large, dichotomously branched tubes arise. The central capsule fills up the +cavity of the bivalved shell almost entirely, and the voluminous dark +phaeodium envelops both to such an extent that the shell and the enclosed +capsule are often hidden in it completely. Therefore I arrived in my first +description of _Coelodendrum_ (1862, _loc. cit._) at the erroneous +conclusion that the capsule lies outside, not inside the shell. The first +accurate figure and description of its structure was given in 1879, by +Hertwig (_loc. cit._, p. 99, Taf. x. fig. 3). The central capsule (_v_) is +here separated from the bivalved shell (_m_) only by a very small distance, +and the oral part of both is hidden in the phaeodium. I find, however, in +the majority of the numerous preparations of the Challenger collection, the +volume of the phaeodium much greater, and it often envelops the entire +shell. + +The Coelographida, finally, have a phaeodium of the most remarkable shape, +since in their bivalved shell a peculiar reserve store or magazine of +phaeodella, which we call the "phaeocapsa" is developed for it (Pl. +126-128, _g.t.m._). The bivalved shell has in these most perfect PHAEODARIA +a structure similar to that in the Coelodendrida; but they differ from the +latter in the stronger development, and greater differentiation of the two +apical galeae, and the large hollow tubes arising from them. These two +helmet-shaped cupolae, the galeae (_g_), which arise from the two valves on +the poles of the sagittal axis, are in the Coelographida usually larger +than the valves themselves, and are not closed, as in the Coelodendrida, +but open by a tubular apophysis at their base, the nasal tube or rhinocanna +(_t_). The apex of the galea is connected with the open mouth of the +rhinocanna by a single or double frenulum (_b_). The two nasal tubes or +rhinocannae (a dorsal and a ventral) lie in the sagittal plane of the body +and run from the base of each galea along the anterior convexity of the +valve to its oral margin. Here is placed the proboscis of the astropyle, +between the two opposed mouths of the rhinocannae (Pl. 128, fig. 2). The +phaeodium is usually hidden entirely {1535}in the two phaeocapsae, which +are composed of the two galeae (_g_), and the two rhinocannae arising from +them (Pl. 127, figs. 4-9). A part of the phaeodella is usually thrown out +by the mouth of the latter (_m_). + +The characteristic colour of the phaeodium exhibits numerous different +tints between green, brown, and black. It seems to be in the majority +blackish-brown or greenish-brown, very often olive, more rarely almost +quite green or red-brown. Usually the colour is so dark, intense and +opaque, that the parts enclosed by the phaeodium, mainly the oral +hemisphere of the central capsule and the astropyle, are completely hidden +in it. The chemical composition of the phaeodium demands further accurate +researches; unfortunately I have not been able to make out its true nature, +since numerous different experiments furnished no certain general results. + +The phaeodella, or the pigment-corpuscles, which compose the phaeodium, +aggregated in hundreds, and in the bigger species in thousands, are usually +spherical, sometimes somewhat ellipsoidal, at other times spheroidal or +lenticular; but usually numerous smaller, irregular, roundish particles are +intermingled between the larger and more regular corpuscles, and often the +main mass forms a very fine black powder. The size of the phaeodella is +very variable, not only in the different species, but also in one and the +same individual. The larger phaeodella have a diameter of 0.01 to 0.02, the +smaller of 0.004 to 0.008 mm.; but there also occur very big forms of 0.04 +to 0.05 mm., or even more, and very small ones of 0.001 mm. or less. +Usually the phaeodium appears as an aggregate of numerous larger and +smaller phaeodella, which are very different in size as well as in the +intensity and tint of their colour, and are irregularly crowded in a black, +powder-like substance. + +The morphological nature of the phaeodella is also difficult to make out. I +have already pointed out in my first description of _Aulacantha_, +_Thalassoplancta_ and _Coelodendrum_ (1862, _loc. cit._), that a great part +of these pigment-corpuscles are true cells, composed of a nucleus and +protoplasm, which contains granules of pigment, and is enveloped by a +membrane. Dr. John Murray, who had during the Challenger voyage the +opportunity of examining numerous different living PHAEODARIA, and staining +them by carmine, also asserts that a great part of those dark corpuscles +are "large black-brown pigment-cells" (1876, _loc. cit._, p. 536). Numerous +preparations of the Challenger collection, well preserved in glycerine, and +stained by carmine, contain PHAEODARIA belonging to different families, the +phaeodium of which contains numerous such "pigment-cells," with a dark red +nucleus, and so similar are these cells, that every histologist should +recognise them. But in strange contrast to this is the fact, that in +numerous other mountings, prepared in the same manner, not a single cell of +this kind is found in the phaeodium, and that the latter is composed only +of irregular pigment-granules. In many PHAEODARIA belonging to different +families I, like Hertwig, could not find a single true nucleated cell in +the phaeodium. + +{1536}A great part of the PHAEODARIA, and usually the bigger forms of +Aulacanthida, Cannorrhaphida, Coelodendrida, Coelographida, &c., exhibit a +peculiar structure of the larger phaeodella, viz., a fine parallel +striation (Pl. 101, figs. 3, 6; Pl. 102, fig. 1; Pl. 103, fig. 1; Pl. 104, +figs. 1-3, &c.). In each phaeodellum may be counted about ten to twenty +such fine parallel stripes (more in the greater, less in the smaller +forms); and in the ellipsoidal phaeodella the stripes are either transverse +rings, perpendicular to their main axis, or ascending obliquely; they often +resemble the convoluted spiral filament of a thread-cell or nettle-cell of +an Acaleph. Sometimes these parallel transverse stripes are very striking. +Another structure is seen in larger phaeodella, namely an aggregate or +cluster of smaller globules, often of equal size, resembling a small +morula. All these minute structures of the phaeodella as well as their +changes in the living PHAEODARIA, require a far more extensive examination +(by means of strong lenses and different chemical reagents), than I could, +unfortunately, devote to them. + +The physiological signification of the phaeodella, therefore, is at present +not yet known; but the general facts quoted above, their constant presence, +position, volume, and composition, make it probable that their +physiological value in the PHAEODARIAN organism is very great. The +following hypotheses may be taken provisionally into consideration:--A. The +phaeodella are peculiar symbiontes, or unicellular algae, comparable to the +xanthellae or zooxanthellae of the other Radiolaria. This hypothesis is +probably correct for those phaeodella which are true nucleated cells; and +the more so, as the majority of PHAEODARIA do not exhibit those common +yellow xanthellae, which are usually found in the SPUMELLARIA and +NASSELLARIA. It is even possible that the latter are absent in all +PHAEODARIA. B. The phaeodella are dark pigment-bodies, which absorb light +and heat in a manner similar to the simple "pigment-eyes" of many lower +animals, and may therefore be optical sense-organs of the PHAEODARIA. This +hypothesis may be supported by a comparison with the large-eyed unicellular +Protist, _Erythropsis agilis_, described by R. Hertwig. C. The phaeodella +are organs of nutrition of the PHAEODARIA and active in their metastasis +("Stoffwechsel"). Regarding them from this point of view, we may suppose +that the phaeodella are secreted products which serve for digestion, acting +like the bile or the saliva of higher animals. Perhaps they too act like +the venomous matter produced in the thread-capsules of the Acalephae. The +suggestion that they are mere excretions, or half-digested matters, as +Hertwig supposes ("halb assimilirte Nahrungs-bestandtheile," 1879, _loc. +cit._, p. 99) seems less probable. The most important fact illustrating +their high signification for the processes of nutrition, digestion and for +effecting changes on matter, seems to be the close relation of the +phaeodium to the astropyle; the radiate operculum of the latter, and the +proboscis arising from it, being constantly covered and completely hidden +by the central main mass of the phaeodium. + +{1537}The skeleton of the PHAEODARIA is always extracapsular, and exhibits +in the majority of this legion such a characteristic shape, form, and +structure, that these organisms may be easily recognised by it, even apart +from the central capsule and the phaeodium. In a few cases, however, the +skeleton is so similar to that of some NASSELLARIA and SPUMELLARIA, that it +may be accidentally confounded with it. In general the skeleton of the +PHAEODARIA is much larger, and much more highly developed, than that of +most other Radiolaria, and exhibits the most wonderful appearances, and the +most marvellous complications, which are found in the whole world of +Protists, or of unicellular organisms. The varied composition and +differentiation of the skeleton alone distinguishes the numerous families, +genera, and species of PHAEODARIA described in the sequel; all the fifteen +families, however, agree so completely in the structure of the central +capsule and the phaeodium described, that we may derive them all +phylogenetically from a small skeletonless family, the Phaeodinida. + +The chemical composition of the skeleton seems to be, in the majority of +PHAEODARIA, somewhat different from that of the other Radiolaria. In a few +groups only, especially in the Cannobelida (_Dictyocha_, _Mesocena_, &c.), +and in a part of the Castanellida and Concharida, the substance of the +skeleton seems to be of pure silica, as in the NASSELLARIA and SPUMELLARIA; +these flinty skeletons, therefore, may be also found fossil. In the +majority of PHAEODARIA, however, the skeleton does not consist of pure +silica, but of an organic silicate; it becomes more or less intensely +stained by carmine, and browned or blacked by fire; in many cases it even +becomes completely burned and destroyed by the prolonged action of heat. +This circumstance explains why PHAEODARIA in general are rare in deep-sea +deposits, as in the common Radiolarian ooze of the Pacific, and why they +are generally absent in fossil deposits. Even the pure Radiolarian rocks of +the Barbados, &c., contain only a few PHAEODARIA, mainly Dictyochida. + +According to the different forms of the skeleton, we may divide the legion +or subclass of PHAEODARIA into two sublegions, four orders, and fifteen +families. Firstly, we may distinguish as two groups the #Phaeocystina#, +without a lattice-shell, and the #Phaeocoscina#, with a lattice-shell +(compare above, p. 5). The #Phaeocystina# comprise three different +families, viz., (1) Phaeodinida, without any skeleton (Pl. 101, figs. 1, +2); (2) Cannorrhaphida, with an incomplete skeleton, composed of numerous +separate, not radial pieces, which are scattered around the capsule in the +calymma (Pl. 101, figs. 3-14; Pl. 114, figs. 7-13), and (3) Aulacanthida +(Pl. 102-105), with an incomplete skeleton, composed of numerous hollow +radial tubes, which pierce the calymma and come in contact by their +proximal ends with the surface of the central capsule. + +The #Phaeocoscina#, or the PHAEODARIA with a lattice-shell (embracing the +great majority of the whole legion) exhibit three principal differences in +the shape of their shell, and from these we distinguish the three following +orders; (A) #Phaeosphaeria#, with a spherical, not bivalved shell (rarely +of an ellipsoidal or lenticular, or another {1538}modified form), without a +shell-mouth or a peculiar constant large opening on the lattice-shell; (B) +#Phaeogromia#, with an ovate or polyhedral, not bivalved shell (often also +of a subspherical, ellipsoidal, or another modified form), constantly +provided with a shell-mouth or a peculiar large opening on one pole of the +main axis of the lattice-shell; (C) #Phaeoconchia#, with a bivalved shell, +composed of two completely separated, hemispherical, cap-shaped or +boat-shaped valves (a dorsal and a ventral), comparable to that of the +Brachiopoda. + +The #Phaeosphaeria#, or those PHAEODARIA the big shell of which is usually +spherical, never bivalved and never provided with a peculiar shell-mouth, +comprise a great number of common and large-sized PHAEODARIA, which may be +arranged into four different families, according to the different structure +of the shell--(1) Orosphaerida (Pl. 106, 107), spherical shell extremely +big and robust, composed of single piece of coarse lattice-work, the thick +bars of which are stratified and contain partly a fine axial-canal, meshes +of the network usually irregularly polygonal, no astral septa in the nodal +points; (2) Sagosphaerida (Pl. 108), spherical shell large-sized, but +extremely delicate and fragile, composed of a single piece of arachnoidal +lattice-work, the thin bars of which are simple solid threads, without +axial-canal, meshes of the network always large and triangular, no astral +septa in the nodal points; (3) Aulosphaerida (Pl. 109-111), spherical shell +large-sized, but very fragile, composed of numerous hollow cylindrical +tubes, which are connected (and at the same time separated) by peculiar +astral septa in the nodal points, meshes either triangular or polygonal; +(4) Cannosphaerida (Pl. 112), spherical shell double, composed of two +concentric shells which are connected by thin hollow radial tubes, the +inner shell simple, solid or fenestrated, with a shell-mouth on the basal +pole, the outer shell composed of hollow cylindrical tubes which are +connected by astral septa in the nodal points. The structure of this outer +shell is the same as in the Aulosphaerida, while the basal mouth of the +inner shell brings this family in closer relationship to the #Phaeogromia#. + +The #Phaeogromia#, or those PHAEODARIA the shell of which is not bivalved, +but provided with a peculiar constant mouth on the oral pole of the main +axis, are in general similar to the NASSELLARIA (Monocyrtida), and may be +divided into five different families, viz., (1) Challengerida (Pl. 99), +shell ovate or subspherical, also often triangular or lenticular, +distinguished by a peculiar diatomaceous structure, an exceedingly fine +tracery of regular hexagonal, very delicate network; (2) Medusettida (Pl. +118-120), shell ovate, campanulate or cap-shaped, distinguished by a +peculiar alveolar structure, with a corona of peculiar hollow, large, +articulated feet around the mouth; (3) Castanellida (Pl. 113), shell +spherical or subspherical, of ordinary simple lattice-work, usually with a +corona of simple solid teeth around the mouth; (4) Circoporida (Pl. +114-117), shell spherical or polyhedral, with panelled or dimpled surface, +distinguished by a peculiar porcellanous structure (numerous thin needles +being {1539}embedded in a punctulate cement-substance), with hollow radial +spines and with a corona of simple solid teeth around the mouth; (5) +Tuscarorida (Pl. 100), shell ovate or subspherical, with smooth surface, of +the same peculiar porcellanous structure as the Circoporida, but with +hollow, very long tubular teeth around the mouth. + +The #Phaeoconchia# are the peculiar and most interesting "PHAEODARIA +bivalva," differing from all other PHAEODARIA, and from all known +Radiolaria in general, in the possession of a bivalved lattice-shell, +composed of a dorsal and a ventral valve. They may be divided into three +families: (1) Concharida (Pl. 123-125), shell with two thick and firm, +regularly latticed valves, which bear no hollow tubes and no cupola or +galea on their apex or sagittal pole; (2) Coelodendrida (Pl. 121), shell +with two thin and fragile, scarcely latticed valves, which bear a conical +cupola or a helmet-shaped galea on their apex, and hollow branched tubes +arising from it (without rhinocanna and frenula); (3) Coelographida (Pl. +122, 126-128), shell with two thin and fragile, scarcely latticed valves, +similar to those of the Coelodendrida, but differing from them in the +development of a peculiar rhinocanna or nasal tube upon each valve; this +tube is connected by an odd or paired frenulum with the apex of the galea, +and both together contain the phaeodium. + +The phylogenetic affinity of the fifteen families enumerated, and the +morphological relationship based upon it, form a very difficult problem. +The whole legion of PHAEODARIA is probably monophyletic, in as much as all +the families may be derived from a single ancestral group, the skeletonless +Phaeodinida (_Phaeodina_ and _Phaeocolla_); but at the same time +polyphyletic, in as much as probably many families have been derived, +independently one from another, from different branches of Phaeodinida; or +in other words, the characteristic malacoma of the PHAEODARIA (the +cannopylean central capsule and the calymma with the phaeodium) may be a +monophyletic product, inherited from a single ancestral form; the manifold +skeleton, however, is certainly a polyphyletic product, originating from +different skeletonless Phaeodinida. + +Among the independent families of PHAEODARIA, derived directly from +skeletonless Phaeodinida by production of a peculiar skeleton, may be the +following: Cannorrhaphida (Pl. 101, probably polyphyletic), Aulacanthida +(Pl. 102-105), Castanellida (Pl. 113), Challengerida (Pl. 99), Concharida +(Pl. 123-125), Circoporida (Pl. 114-117) and Tuscarorida (Pl. 100). The +four families of #Phaeosphaeria# (the Orosphaerida, Sagosphaerida, +Aulosphaerida and Cannosphaerida (Pl. 106-112), may be derived perhaps from +the Castanellida; and the Medusettida (Pl. 118-120), have been perhaps +derived from the Challengerida. The complicated affinities of these groups +are however difficult to explain. The Coelodendrida (Pl. 121) are probably +derived from the Concharida, and the Coelographida (Pl. 126-128) from the +Coelodendrida. + +The geometrical fundamental form of the shell is in the majority of +PHAEODARIA monaxonial, corresponding to the main axis of the enclosed +central capsule; the {1540}astropyle of the latter, placed on the oral pole +of the main axis, corresponds to the mouth of the shell in all +#Phaeogromia#. In the #Phaeosphaeria#, where no peculiar shell mouth is +developed, the general fundamental form of the shell is usually homaxonial +or spherical, often an endospherical polyhedron, rarely ellipsoidal or +spindle-shaped (with prolonged main axis), or lenticular (with shortened +main axis). The bivalved #Phaeoconchia# have usually either an amphithect +shell (with the same fundamental form as the Ctenophora), or a dipleuric, +bilaterally symmetrical shell (with a dorsal and a ventral valve, a right +and a left parapyle). A small number of PHAEODARIA (mainly Circoporida) are +remarkable on account of the regular polyhedral form of their shell, the +geometrical axes of which resemble crystalline axes and are defined by +regular radial tubes; as the octahedral _Circoporus_ (Pl. 117, fig. 6), the +dodecahedral _Circorrhegma_ (fig. 2), and the icosahedral _Circogonia_ +(fig. 1). + +The siliceous or silicate bars, which compose the skeleton of the +PHAEODARIA, are in the majority hollow tubes, filled up by jelly; in some +other families, however, they are solid rods, as in the NASSELLARIA and +SPUMELLARIA. Such usual lattice-work, composed of solid rods, occurs only +in the families Sagosphaerida (Pl. 108), Castanellida (Pl. 113), and +Concharida (Pls. 123-125). A quite peculiar structure, a diatomaceous +tracery of extremely fine and regular hexagonal frames, distinguishes the +Challengerida (Pl. 99). The hollow cylindrical tubes, which are found in +the other families, appear in three different forms, simple, articulate, +and provided with an axial thread. Simple hollow tubes, which are neither +articulate nor provided with an axial thread, occur in the Cannorrhaphida +(Pl. 101), Aulacanthida (Pl. 102-105), Coelodendrida (Pl. 121, 122), and +Coelographida (Pl. 126-128). In all these families the hollow cylindrical +tubes have a very thin wall and contain a wide cavity, filled only by +jelly. The Orosphaerida (Pl. 106, 107), differ in the reduction of the +cavity, which becomes very narrow (often rudimentary or lost), whilst the +walls of the tubes become extremely thickened and stratified, numerous +concentric layers of silica being disposed one over the other. The hollow +cylindrical tubes contain an axial filament, or a thin thread of silica, +placed in its axis, in the families Aulosphaerida (Pl. 109-111), +Cannosphaerida (Pl. 112), Circoporida (Pl. 114-117), and Tuscarorida (Pl. +100). Usually the axial filament is connected with the thin wall of the +tube by numerous horizontal branches. A quite peculiar structure +distinguishes the Medusettida (Pl. 118-120); their hollow tubes, extremely +prolonged, are articulate owing to the presence of numerous, regular, +equidistant transverse septa; these are pierced by a short tubule, similar +to the siphon of the shells of _Nautilus_; this remarkable alveolar +structure also occurs in the peripheral part of their shell-wall (and +sometimes in the whole shell), numerous small polyhedral chambers or +alveoles which communicate by small openings, being developed; they become +easily filled with air in the dry shell (Pl. 120, figs. 11-16). + +{1541}The substance of the siliceous or silicated shell-wall is, in the +majority of PHAEODARIA, homogeneous and structureless, as in the +SPUMELLARIA and NASSELLARIA; but sometimes it acquires a peculiar +structure. The thickened wall of the hollow tubes in the Orosphaerida and +in several Aulacanthida (Pl. 105, figs. 6-10) becomes distinctly +stratified, concentric strata being disposed one over the other. A very +remarkable structure, differing from that in all other Radiolaria, is found +in the porcellanous shell of the Circoporida (Pl. 114-117), and Tuscarorida +(Pl. 100). The thickened wall of the opaque shell is here composed of a +peculiar silicated cement, which encloses numerous very thin and +irregularly scattered needles (Pl. 115, figs. 6-9; Pl. 116, fig. 3). Dry +fragments of these shells, observed by a strong lens, appear finely +punctulate, and probably air, entering into these fine porules of the +cement, causes the white colour and the calcareous or porcellanous +appearance of the opaque dry shell. Its surface is smooth in the +Tuscarorida (Pl. 100), panelled in the Circoporida (Pl. 114-117). + +The hollow or solid spines, which arise from the shell of the PHAEODARIA, +exhibit an extraordinary variety and elegance in the production of +different branches, bristles, hairs, secondary spine, and thorns, hooks, +anchor-threads, pencils, spathillae, &c. These appendages are developed +similarly to those of many SPUMELLARIA, but exhibit a far greater variety +and richness in form. They are organs partly for protection, partly for +retention of food. They are much more interesting than in other Radiolaria. + +_Synopsis of the Orders and Families of_ PHAEODARIA. + + ------------------------------------------------------------------------- + I. Order PHAEOCYSTINA. + Skeleton absent or incomplete, composed of numerous single scattered + pieces, without connection. Central capsule placed in the centre of + the calymma. + ------------------------------------------------------------------------- + Skeleton completely absent, 1. PHAEODINIDA. + + Skeleton composed of numerous + scattered pieces, not of radial tubes, 2. CANNORRHAPHIDA. + + Skeleton composed of numerous hollow + radial tubes, the proximal ends of which + are in contact with the central capsule, 3. AULACANTHIDA. + ------------------------------------------------------------------------- + II. Order PHAEOSPHAERIA. + Skeleton a simple or double lattice-shell, not bivalved, without a + peculiar shell-mouth (shell usually spherical, rarely of a modified + form, always without peristome). Central capsule placed in the centre + of the shell-cavity. + ------------------------------------------------------------------------- + { Network very robust and + Shell composed { coarse, with irregular + of a simple { polygonal meshes; bars + non-articulated { very thick, partly hollow, 4. OROSPHAERIDA. + lattice-plate, { + without astral { Network very delicate and + septa in the { fragile, with subregular, + nodal points. { triangular meshes; rods + { very thin, filiform, always + { solid, 5. SAGOSPHAERIDA. + + Shell composed { Shell articulated, with + of numerous { astral septa, without a + hollow, tangential { simple central shell, 6. AULOSPHAERIDA. + cylindrical tubes, { + which are { Shell double, composed of + separated by { two concentric shells; + astral septa in { the outer articulated, the + the nodal points. { inner simple, 7. CANNOSPHAERIDA. + ------------------------------------------------------------------------- + III. Order PHAEOGROMIA. + Skeleton a simple lattice-shell, not bivalved, constantly provided + with a peculiar large shell-mouth placed on the oral pole of the + main axis; peristome usually surrounded by peculiar feet or teeth. + (Shell either spherical or ovate, or of another form). Central + capsule excentric, placed in the aboral half of the shell-cavity. + ------------------------------------------------------------------------- + { Structure of the shell + { diatomaceous, with very + { delicate and regular + { hexagonal pores. No + { articulate feet, 8. CHALLENGERIDA. + Structure of the { + shell not { Structure of the shell + porcellanous { alveolar, with hollow + (without needles { alveoles between a double + imbedded in { plate. A corona of + a punctulate { articulated feet around + cement-substance). { the mouth, 9. MEDUSETTIDA. + { + { Structure of the shell of + { simple lattice-work, neither + { diatomaceous nor alveolar. + { No articulate feet, 10. CASTANELLIDA. + + Structure of the { Surface of the shell + shell porcellanous, { (sphericalpanelled or + with peculiar fine { dimpled or polyhedral). + needles imbedded { Peristome flat, 11. CIRCOPORIDA. + in a punctulate { + cement-substance { Surface of the shell + (a circle of { smooth, even (ovate or + pores around the { subspherical). Peristome + base of each tube). { prominent, 12. TUSCARORIDA. + ------------------------------------------------------------------------- + IV. Order PHAEOCONCHIA. + Skeleton a bivalved lattice-shell, composed of a dorsal and a ventral + valve which are completely separated (rarely connected by a ligament + on the aboral pole). Central capsule enclosed between the two valves. + ------------------------------------------------------------------------- + The two valves of the bivalved shell thick and firm, + regularly latticed, without a galea or cupola on + their apex, and without hollow tubes, 13. CONCHARIDA. + + The two valves { Galea without rhinocanna + of the bivalved { or nasal tube, without + shell very thin { frenula, 14. COELODENDRIDA. + and fragile, { + scarcely latticed, { Galea with a rhinocanna or + each with a conical { nasal tube, both connected + cupola or a { by an odd or + helmet-shaped galea { paired frenulum, 15. COELOGRAPHIDA. + on its sagittal { + pole or apex, and { + with hollow tubes. { + + + +Order I. PHAEOCYSTINA, Haeckel (1879). + +_Definition._--PHAEODARIA without lattice-shell, either without any +skeleton, or with an incomplete skeleton, composed of numerous single +pieces, which are scattered in the calymma without connection. Central +capsule placed in the centre of the spherical calymma. + + + +{1543}Family LXXI. #Phaeodinida#, Haeckel (Pl. 101, figs. 1, 2). + + _Phaeodinida_, Haeckel, 1879, Sitzungsb. med.-nat. Gesellsch. Jena, Dec. + 12, p. 4. + +_Definition._--PHAEODARIA without skeleton. Central capsule with one to +three (or more) openings, placed in the centre of the spherical naked +calymma. + +The family #Phaeodinida# is the simplest and most primitive of the +PHAEODARIA, and differs from all the other families of this legion in the +complete absence of a skeleton. It bears, therefore, the same relation to +the latter as the Thalassicollida do to the other SPUMELLARIA. The soft +body is only composed of the central capsule with the nucleus, and the +calymma with the phaeodium. + +Of course it is quite possible that the skeletonless PHAEODARIA, which we +regard here as the ancestral family of that legion, may be either members +of other families which have lost their skeleton accidentally, or young +PHAEODARIA which have not yet developed a skeleton. But in some +preparations of the Challenger certain large, well-preserved PHAEODARIA, +without any trace of skeleton, are not rare; and since I myself have +observed a complete living _Phaeodina_, I have no doubt that they are +independent, primordial forms (like _Actissa_, _Thalassicolla_, +_Cystidium_, _Nassella_, &c.). Probably also two skeletonless PHAEODARIA +belong to this family which are figured by R. Hertwig, in 1879, in his +Organismus d. Radiol. (Taf. x. fig. 1, 11); this author, however, supposed +that they had lost their original skeleton. + +The three species of Phaeodinida which are described in the sequel +represent two different genera, _Phaeodina_ and _Phaeocolla_, already +distinguished in my first note on the PHAEODARIA (Sitzungsb. med.-nat. +Gesellsch. Jena, 1879, Dec. 12, p. 4). _Phaeodina_ is a true TRIPYLEA, and +has the usual three openings which occur in the majority of PHAEODARIA, a +large astropyle or main-opening on the oral pole of the main axis, and a +pair of lateral accessory openings, or parapylae, on the aboral pole. +_Phaeocolla_, however, has only a single opening, the astropyle, and agrees +therefore with those PHAEODARIA which possess no parapylae (Challengerida, +Medusettida, Castanellida, &c.). + +The complete body is in all observed Phaeodinida a small jelly sphere of 1 +to 3 mm. in diameter, with a transparent cortical layer and an opaque dark +central part. This latter is the phaeodium, in which the central capsule is +hidden, surrounded on all sides by the gelatinous spherical calymma; the +smooth surface of the latter is spherical. + +The _central capsule_ of the Phaeodinida (Pl. 101, figs. 1, 2), is either +spherical or spheroidal, somewhat lenticular, slightly depressed in the +direction of the main axis. Its diameter is between 0.15 and 0.25. Its +double membrane exhibits the same structure as in the other PHAEODARIA. The +thick, double-contoured outer membrane is separated from the thin and +delicate inner membrane by a clear space, filled up by jelly or by a fluid; +the two are connected in _Phaeocolla_ (fig. 1) only at the astropyle, in +_Phaeodina_ (fig. 2), {1544}they are also connected at the two parapylae. +The radiate operculum of the astropyle opens by a tubular prolongation or +proboscis, which is very long in the former, shorter in the latter. The two +parapylae of the latter also bear short tubules. The protoplasm, enclosed +in the inner membrane, contains numerous small circular vacuoles. The large +central nucleus is sometimes spherical or ellipsoidal, at other times +spheroidal or lenticular; it always contains numerous nucleoli. One +specimen observed, with two nuclei, was apparently engaged in self-division +(fig. 2). + +The spherical gelatinous calymma, in the centre of which the central +capsule is placed, has a diameter of 1 to 2 mm. In the specimen of +_Phaeodina tripylea_, which I observed living, it exhibited exactly the +same shape as the figure of _Dictyocha stapedia_ in Pl. 101, fig. 10; the +only distinction in this latter being indicated by the pileated pieces of +the skeleton on the surface. The jelly-sphere contained numerous roundish +or globular alveoles of very different sizes, and between them an areolated +network of protoplasm; the latter has arisen from the outer surface of the +calymma in the form of very numerous, radiating, partly branched and +anastomosing pseudopodia. The dark and opaque centre of the jelly-sphere is +filled up by the granular, blackish-brown phaeodium, which envelops the +oral half of the central capsule completely; it exhibits the same +characters as in all the other PHAEODARIA. + +_Synopsis of the Genera of Phaeodinida._ + + Central capsule with a single opening (an astropyle + on the oral pole), 656. _Phaeocolla_. + + Central capsule with three openings (an oral + astropyle and two aboral parapylae), 657. _Phaeodina_. + + + +Genus 656. _Phaeocolla_,[274] Haeckel, 1879, Sitzungsb. med.-nat. +Gesellsch. Jena, Dec. 12, p. 4. + +_Definition._--#Phaeodinida# with a single aperture to the central capsule +(an astropyle with radiate operculum, placed on the oral pole of the main +axis). + +The genus _Phaeocolla_ may be regarded as the simplest form of all +PHAEODARIA, and perhaps as the common ancestral form of this legion. It has +no skeleton, and the central capsule exhibits only a single aperture on one +pole of the main axis. In this it agrees with the Challengerida, +Medusettida, and Castanellida, which have also no parapylae or secondary +openings. + + +1. _Phaeocolla primordialis_, n. sp. (Pl. 101, fig. 1). + +Central capsule subspherical, or somewhat depressed in the direction of the +main axis. The oral pole of the latter exhibits a large astropyle, or a +radiate operculum, about as broad as the {1545}nucleus. From its centre +arises a conical mammilla, prolonged into a thin, cylindrical, S-like +tubulus, the proboscis, which is about as long as the diameter of the +capsule. The outer membrane of the capsule is thick and double-contoured; +the inner is very thin, but distinct, and includes finely granulated +protoplasm, and numerous spherical, clear vacuoles, each with some small +granules. Nucleus spheroidal, depressed in the direction of the main axis, +containing numerous dark, irregularly amoebiform nucleoli. The diameter of +the nucleus is about equal to the radius of the central capsule. The +extracapsular calymma is an alveolated sphere, the diameter of which is six +to eight times that of the capsule. The inner part of it contains an +irregular, blackish phaeodium, which surrounds and hides the oral half of +the central capsule. + +_Dimensions._--Diameter of the central capsule 0.16, of the nucleus 0.08, +of the calymma 1.0 to 1.2. + +_Habitat._--Central Pacific, Station 271 to 274, surface. + + + +Genus 657. _Phaeodina_,[275] Haeckel, 1879, Sitzungsb. med.-nat. Gesellsch. +Jena, Dec. 12, p. 4. + +_Definition._--#Phaeodinida# with three apertures to the central capsule +(an astropyle on the oral pole of the main axis, and two lateral parapylae +on both sides of the aboral pole). + +The genus _Phaeodina_ has the same structure of the central capsule as the +majority of PHAEODARIA; one large main-opening or astropyle on the oral +pole of the main axis, and two smaller lateral accessory openings or +parapylae on each side of the aboral pole: it is therefore a true Tripylean +genus, like the majority of PHAEODARIA. + + +1. _Phaeodina tripylea_, Haeckel (Pl. 101, fig. 2). + + ? _Tripylea_ sp., R. Hertwig, 1879, Organismus d. Radiol., Taf. x. figs. + 1, 11. + +Central capsule spheroidal or lenticular, somewhat depressed in the +direction of the main axis. Astropyle with a strongly ribbed, radiate +operculum, scarcely one-third as broad as the diameter of the capsule, and +prolonged into a short tubular proboscis. Parapylae also with short tubular +openings. The outer strong (double-contoured) membrane of the central +capsule is separated from the inner thin (simple-contoured) membrane by a +wide interval, filled up by a clear fluid or jelly; only at the three +apertures both membranes are in direct connection. The granulated +protoplasm contains numerous vacuoles, and surrounds a large spheroidal +nucleus, with numerous small nucleoli. The voluminous calymma in a +specimen, observed living, was alveolar, and the ramification of the +pseudopodia, as well as the formation of the dark brown phaeodium, very +similar to that of _Dictyocha stapedia_ (Pl. 101, fig. 10). Another +specimen, figured in Pl. 101, fig. 2, exhibited the first stages of +self-division; the reticulated nucleus and the radiate operculum of the +astropyle were already doubled, and the two membranes of the capsule +between them constricted in the median plane. To this species belong +probably the central capsules figured by R. Hertwig, _loc. cit._ + +{1546}_Dimensions._--Diameter of the central capsule 0.15 to 0.25, of the +nucleus 0.06 to 0.1, of the calymma 0.8 to 1.2. + +_Habitat._--Mediterranean; Portofino, near Genoa (Haeckel); Messina +(Hertwig). + + +2. _Phaeodina cannopylea_, n. sp. + +Central capsule subspherical, scarcely depressed in the direction of the +main axis. Astropyle with a finely ribbed radiate operculum, about as broad +as the radius of the capsule, prolonged into a slender, tubular proboscis +which is S-shaped, about as long as the radius, and similar to that of +_Phaeocolla primordialis_, Pl. 101, fig. 1. Parapylae also tubular, with +two slender prolongations, half as long and broad as the proboscis of the +parapyle. Nucleus spheroidal, about half as broad as the capsule. This +species differs from the preceding mainly in the cylindrical slender +prolongations of the three apertures, which are similar to those of +_Aulosphaera_ and _Aularia_ (Pl. 111, fig. 2). + +_Dimensions._--Diameter of the central capsule 0.2, of the nucleus 0.1, of +the calymma 1.2 to 1.5. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + + +Family LXXII. #CANNORRHAPHIDA#, Haeckel, 1879 (Pl. 101, figs. 3-14; Pl. +114, figs. 7-13). + + _Cannorrhaphida_, Haeckel, 1879, Sitzungsb. med.-nat. Gesellsch. Jena, + Dec. 12, p. 4. + +_Definition._--PHAEODARIA with an incomplete skeleton, composed of numerous +separate, not radially arranged pieces, which are either hollow tangential +spicula or cap-shaped dishes, or fenestrated rings, scattered loosely in +the calymma. Central capsule placed in the centre of the spherical calymma. + +The family #Cannorrhaphida# comprises those PHAEODARIA in which the +incomplete skeleton is represented by numerous separate pieces of silica, +which exhibit very different forms, and are scattered tangentially on the +surface of the spherical calymma, sometimes also throughout its jelly-mass. +They agree in this peculiar character with the Thalassosphaerida (among the +SPUMELLARIA) and bear the same relation to the skeletonless Phaeodinida as +the Thalassosphaerida do to the Thalassicollida (compare pp. 10 and 29). +The Cannorrhaphida represent the former group among the PHAEODARIA. They +differ from the following family, the Aulacanthida, in the arrangement and +position of the hollow spicula, which are never directed radially and never +touch the central capsule, as is constantly the case in the latter. + +Two genera of Cannorrhaphida have been hitherto known. The first species +observed in a complete and living state (at Messina in 1859) was +_Cannobelos cavispicula_, described in 1862 in my Monograph as +_Thalassoplancta cavispicula_ (_loc. cit._, p. 261, Taf. iii. figs. 10-13). +I there figured a complete living specimen with expanded pseudopodia and a +double central capsule (in the stage of self-division). The latter was +surrounded by an {1547}alveolar calymma and by a voluminous mass of +blackish-brown pigment, the phaeodium; numerous, long, hollow, cylindrical +tubes were scattered on the surface of the calymma. At that time I did not +know the tripylean character of the central capsule and the peculiar +radiate operculum in the PHAEODARIA, and therefore placed _Thalassoplancta +cavispicula_ among the Thalassosphaerida. + +The second description of a complete form of Cannorrhaphida was given in +1879 by R. Hertwig, under the name _Dictyocha fibula_ (Organismus d. +Radiol., p. 89, Taf. ix. fig. 5). The genus _Dictyocha_ had been already +founded by Ehrenberg in 1838, with the following definition:--"Lorica +simplex, univalvis, silicea, laxe reticulata aut stellata" (Abhandl. d. k. +Akad. d. Wiss. Berlin, 1838, p. 128). Ehrenberg had found only scattered +pieces of the skeleton, fossil in Tertiary rocks. He placed them among the +_Bacillaria_ (= _Diatomaceae_), but added, that they may be possibly +scattered spicula of Sponges ("forsan Spongiarum ossicula"). + +In 1859 I myself observed similar forms of _Dictyocha_ at Messina, and +first recognised them as true Radiolaria. But I placed them at that time +among the Acanthodesmida, beside _Prismatium_, supposing that a small +spherical body which I had sometimes seen in the cavity of the pileated +pieces (probably a phaeodellum) was the small central capsule (Monogr. d. +Radiol., 1862, p. 271, Taf. xii. figs. 3-6). The complete body of +_Dictyocha_ was not described till 1879, when R. Hertwig gave a full +description of its peculiar structure, and especially of the great central +capsule, which resembles that of the other PHAEODARIA. He first stated that +the singular pileated pieces described by Ehrenberg were not complete +shells, but isolated pieces of the skeleton, which are scattered in the +jelly-envelope around the central capsule in a mode similar to the spicula +of _Thalassoplancta_, _Thalassosphaera_ and _Sphaerozoum_. Hertwig also +first recognised that the thin rods, which compose the reticular pileated +pieces of the skeleton in _Dictyocha_, are not solid bars, but thin hollow +tubules, similar to the hollow rods of _Aulacantha_ and of other +PHAEODARIA. + +Numerous complete and well-preserved specimens of _Dictyocha_, which I +found in the collection of the Challenger, have convinced me that the +accurate description of R. Hertwig is correct in every respect, and that +these remarkable bodies are true PHAEODARIA, most closely allied to +_Cannobelos_ (= _Thalassoplancta_) and to _Aulacantha_ (compare Pl. 101, +fig. 10). I now regard them as representatives of a peculiar subfamily of +Cannorrhaphida, which I call Dictyochida. To the same subfamily also belong +the small annular bodies which Ehrenberg described in 1841 as _Mesocena_ +(_loc. cit._, p. 401), and the elegant, more complicated, reticular and +pileated bodies, which Stoehr figured in 1880 under the name _Distephanus_ +(Palaeontogr., vol. xxvi. p. 121). These peculiar bodies are also only +isolated pieces of the siliceous skeleton, and are scattered tangentially +in great numbers in the calymma, around the tripylean central capsule. A +still higher degree of development is attained by the interesting forms +{1548}which I describe here as _Cannopilus_ (Pl. 114, figs. 7-13). All +these peculiar forms may be derived from the simple annular pieces of +skeleton, which are aggregated in great numbers in the calymma of +_Mesocena_. The pieces of the skeleton of these Dictyochida never assume +the form of slender, cylindrical, tangential tubules which is +characteristic of the Cannobelida. + +A third subfamily of Cannorrhaphida, the Catinulida, is represented by the +remarkable new genus _Catinulus_ (Pl. 117, fig. 8). The single pieces of +the skeleton, scattered in hundreds or thousands throughout the calymma, +are here not composed of hollow rods, as in the two former subfamilies, but +are solid hemispherical caps, or small, more flatly vaulted dishes, with a +peculiar radial striation. All the complete specimens of _Catinulus_ which +I could examine possessed four equal central capsules, united in one +spherical calymma. + +The common character which unites the three rather different subfamilies, +the Cannobelida, Dictyochida and Catinulida into a single family, and which +separates this family, the Cannorrhaphida, from the other PHAEODARIA, is to +be found in the composition of the rudimentary skeleton from numerous +single pieces, which are loosely scattered either on the surface of the +calymma, or throughout its jelly-mass, and which are never arranged +radially and never touch the central capsule as is always the case in the +closely allied Aulacanthida. + +The slender spicula of the Cannobelida are cylindrical or spindle-shaped, +tubular, scattered in variable numbers, but always in a tangential +direction on the surface of the calymma. Usually they are 0.2 to 0.5 long, +and 0.005 to 0.03 broad; either straight or slightly curved; smooth and +simple in _Cannobelos_, spiny or branched in _Cannorrhaphis_ (Pl. 101, +figs. 3-5). Their wall is thin and fragile, their diameter sometimes equal +throughout their whole length, at other times tapering towards both ends. +Their cavity is filled by jelly, and seems to be open at both ends, since +the purified and dried spicula constantly become filled by air. + +The peculiar pieces of silica which compose the skeleton of the Catinulida +are not hollow, like the rods of the other Cannorrhaphida, but concave +hemispherical cups or more flatly vaulted little dishes, the thin flinty +wall of which is slightly thickened at the circular margin, and radially +striped above it. In all three species of _Catinulus_ observed they were +scattered throughout the calymma in hundreds or thousands (Pl. 117, fig. +8). Their relation to the Dictyochida is doubtful. Perhaps the small cups +of _Catinulus_ may be derived from the simple rings of _Mesocena_, by +development of an operculum on one side of the ring. + +The skeleton of the Dictyochida is much more developed and possesses a +higher morphological interest; the numerous different forms, however, which +its pieces here assume, may be all derived from the simple circular ring of +_Mesocena_. This ring is formed by a thin, hollow, cylindrical, or +prismatic rod, sometimes circular or elliptical, at {1549}other times +polygonal. From its margin small, hollow, radial spines often proceed (Pl. +101, fig. 9). In _Dictyocha_ there arise from the ring two, three, four or +more siliceous bars or arches, which form one or more bulges over one side +of the ring; usually the little fenestrated shell thus produced assumes the +form of a three-sided or four-sided pyramid, or of a little hat with three +or four meshes (Pl. 101, figs. 10-14). From this _Dictyocha_ (in a +restricted sense) we separate the genus _Distephanus_, in which the little +pyramids become truncated, so that one central apical mesh (the apical or +upper ring) is surrounded by four, five, six or eight lateral meshes, the +sides of the pyramid (Pl. 114, figs. 7-9). The edges of the small pyramid +are formed by the same number of siliceous bars arising from the ring and +alternating with the meshes. Radial spines in different numbers and +arrangements arise from the corners of the two parallel rings, as well from +the smaller apical as from the larger basal ring. The simple apical ring of +_Distephanus_ becomes divided or fenestrated in the highest developed genus +of this subfamily, in _Cannopilus_ (Pl. 114, figs. 10-13); each pileated +piece of the skeleton exhibits here two rows of alternating lateral meshes, +an upper row of smaller and a lower row of larger meshes. + +The majority of Dictyochida are armed with spines or thorns, which arise in +a regular manner from different points of the annular or pileated pieces. +In the ancestral genus, _Mesocena_, radial spines start from the corners of +the simple ring in centrifugal direction, and lie horizontally in its +plane. As these primary corner-spines determine the radial composition of +the more highly developed genera we call them perradial (lying in rays of +the first order). In _Dictyocha_ and _Distephanus_ commonly (but not quite +constantly) these perradial spines alternate with the ascending bars which +bisect the sides of the basal ring; these bars are therefore interradial +(lying in rays of the second order); consequently also the corners of the +apical ring of _Distephanus_ are interradial. The latter also often bear +small thorns or teeth. Other teeth frequently start in centripetal +direction from the lower or basal ring, on the side of the perradial +spines, and frequently they are directed obliquely downwards. + +In _Dictyocha_ and _Distephanus_ are frequently found remarkable twin +pieces, composed of two pileated and reticulated skeleton pieces. These are +united by their basal rings loosely in such a way that they form together a +small fenestrated subspherical body; the union is strengthened by those +small teeth of the basal rings, which are directed downwards and catch one +into the other (Pl. 101, fig. 12; Pl. 114, fig. 8). A similar twin piece +has been already observed by Stoehr in the fossil _Distephanus rotundus_, +and upon this was founded this genus. Since the teeth of the two opposed +basal rings, catching one into the other, seem to be specially adapted for +the composition of those small double pyramids, it is probable that the +latter possess a special protective function in these PHAEODARIA, and +perhaps envelop their phaeodella or their flagellate spores (?). In every +case these formations are very remarkable. + +{1550}_The Central Capsule_ of the Cannorrhaphida seems to possess the same +shape in the three subfamilies, and to agree in general with that of the +Aulacanthida. In a living specimen of _Dictyocha stapedia_, which I +observed at Ceylon (Pl. 101, fig. 10), the three openings of the TRIPYLEA +were distinct; the radiate operculum of the astropyle (on the oral pole) +was surrounded by the granules of the dark phaeodium, whilst on the +opposite aboral side, two parapylae or conical secondary openings were +visible. The voluminous spherical calymma (about four times as broad as the +central capsule) contained numerous large alveoles (as in _Aulosphaera_) +and its surface was protected by numerous pileated pieces of the skeleton; +the basal ring of the latter was placed tangentially in the spherical +surface of the calymma, their apical spine being directed outwards. The +pseudopodia, arising from the central capsule and forming a network between +the alveoles of the calymma, radiated outwards in great number from its +surface (Pl. 101, fig. 10). + +The propagation by self-division seems to be very frequent in the +Cannorrhaphida. I frequently found two equal central capsules in one +calymma, as in the first observed species, _Cannobelos cavispicula_, and in +_Cannorrhaphis spinulosa_ (Pl. 101, fig. 3), sometimes also in _Dictyocha_ +and _Distephanus_. As already mentioned, _Catinulus_ constantly exhibited +four central capsules united in each calymma. + +_Synopsis of the Genera of Cannorrhaphida._ + + ------------------------------------------------------------------------- + I. Subfamily Cannobelida. + Pieces of the skeleton cylindrical or spindle-shaped tangential + tubules. + ------------------------------------------------------------------------- + Tubules simple, smooth, 658. _Cannobelos_. + + Tubules spiny or branched, 659. _Cannorrhaphis_. + ------------------------------------------------------------------------- + II. Subfamily Catinulida. + Pieces of the skeleton hemispherical or cap-shaped, solid. + ------------------------------------------------------------------------- + Caps or hemispherical pieces of the skeleton + solid, with radiate margin and circular opening, 660. _Catinulus_. + ------------------------------------------------------------------------- + III. Subfamily Dictyochida. + Pieces of the skeleton either simple rings or pileated or pyramidal + bodies, composed of thin hollow rods and reticular meshes. + ------------------------------------------------------------------------- + Flinty pieces simple { Basal ring simple, not + or arched rings, not { arched or fenestrated, 661. _Mesocena_. + truncated pyramids, { + with a basal ring, { Basal ring fenestrated, + but without apical { with two or more arches, + ring. { vaulted over one side, 662. _Dictyocha_. + + Flinty pieces of the { Apical ring simple, not + skeleton resembling { fenestrated (one girdle + a truncated pyramid, { of meshes on each piece), 663. _Distephanus_. + with an upper smaller { + apical ring, and a { Apical ring fenestrated + lower larger basal { (two girdles of meshes + ring. { on each piece), 664. _Cannopilus_. + + + +{1551}Subfamily 1. CANNOBELIDA, Haeckel. + +_Definition._--#Cannorrhaphida# with numerous hollow cylindrical or +spindle-shaped tubes, which lie tangentially scattered on the surface of +the spherical calymma. + + + +Genus 658. _Cannobelos_,[276] n. gen. + +_Definition._--#Cannorrhaphida# with a skeleton composed of tubular +acicular pieces, which are smooth, cylindrical or spindle-shaped tangential +needles, without spines and branches. + +The genus _Cannobelos_, and the following closely allied _Cannorrhaphis_, +represent the peculiar subfamily Cannobelida, differing from the other +Cannorrhaphida in the acicular form of the pieces of the skeleton, which +are tangentially scattered on the surface of the spherical calymma. The +cylindrical or spindle-shaped hollow needles are smooth in _Cannobelos_, +whilst in _Cannorrhaphis_ they are studded with lateral spines or branches. + + +1. _Cannobelos cavispicula_, Haeckel. + + _Thalassoplancta cavispicula_, Haeckel, 1862, Monogr. d. Radiol., p. 261, + Taf. iii. figs. 10-13. + + _Thalassicolla cavispicula_, Haeckel, 1860, Monatsber. d. k. preuss. + Akad. d. Wis. Berlin, p. 798. + + _Cannorrhaphis cavispicula_, Haeckel, 1881, Prodromus, p. 470. + +Tangential tubes cylindrical, more or less curved, gradually tapering +towards the two pointed ends. Calymma with a voluminous phaeodium. + +_Dimensions._--Length of the tubular spicule 0.25, breadth 0.003. + +_Habitat._--Mediterranean, Messina, surface. + + +2. _Cannobelos calymmata_, n. sp. + +Tangential tubes cylindrical, straight, of equal breadth throughout their +whole length, closed by a hemispherical cap on the two rounded ends. +Calymma very voluminous, with a small phaeodium. + +_Dimensions._--Length of the tubular spicula 0.3 to 0.5, breadth 0.004 to +0.008. + +_Habitat._--Central Pacific, Stations 263 to 274, surface. + + +3. _Cannobelos thalassoplancta_, n. sp. + +Tangential tubes spindle-shaped, straight, gradually tapering towards the +two pointed ends. Calymma and the included phaeodium rather voluminous. + +_Dimensions._--Length of the tubular spicula 0.15 to 0.2, breadth in the +middle part 0.02. + +_Habitat._--Tropical Atlantic, Station 347, surface. + + + +{1552}Genus 659. _Cannorrhaphis_,[277] Haeckel, 1879, Sitzungsb. med.-nat. +Gesellsch. Jena, Dec. 12, p. 4. + +_Definition._--#Cannorrhaphida# with a skeleton composed of tubular +acicular pieces, which are spiny, cylindrical or spindle-shaped tangential +needles, either with lateral spines or branches. + +The genus _Cannorrhaphis_ differs from the preceding closely allied +_Cannobelos_ in the spiny shape of the tangential acicular spicula, which +are studded either with short spines or with longer lateral branches. + + +1. _Cannorrhaphis spinulosa_, n. sp. (Pl. 101, figs. 3, 4). + +Tangential tubes cylindrical, straight, gradually tapering towards the two +pointed ends, densely studded with conical spines, arising perpendicularly. +(The specimen figured, fig. 3, exhibited two ovate central capsules, each +of which contained two large nuclei, with numerous nucleoli.) + +_Dimensions._--Length of the tubular spicula 0.3 to 0.5, breadth 0.01 to +0.015. + +_Habitat._--North Pacific, Station 244, surface. + + +2. _Cannorrhaphis lampoxanthium_, n. sp. + +Tangential tubes cylindrical, more or less curved, suddenly tapering +towards the two pointed ends, densely studded with irregular conical spines +of unequal length, which arise obliquely from their surface. + +_Dimensions._--Length of the tubular spicula 0.4 to 0.5, breadth 0.005 to +0.008. + +_Habitat._--South Pacific, Station 289, depth 2550 fathoms. + + +3. _Cannorrhaphis lappacea_, n. sp. + +Tangential tubes spindle-shaped, gradually tapering towards the two pointed +ends, densely studded with irregular lateral branches, which are partly +simply, partly forked, more or less curved, and arise obliquely from their +surface. + +_Dimensions._--Length of the tubular spicula 0.2 to 0.3, breadth 0.015 to +0.025. + +_Habitat._--Central Pacific, Station 271, surface. + + +4. _Cannorrhaphis spathillata_, n. sp. (Pl. 101, fig. 5). + +Tangential tubes cylindrical, thin and straight, regularly zigzag, with +pointed, regularly alternating lateral spines, with an elegant spathilla, +or a cap-shaped verticil of eight to ten recurved spines on the two ends. + +_Dimensions._--Length of the tubular spicula 0.3, breadth 0.003. + +_Habitat._--Indian Ocean, Cocos Islands (Rabbe), surface. + + + +{1553}Subfamily 2. CATINULIDA, Haeckel. + +_Definition._--#Cannorrhaphida# with a skeleton composed of numerous +cap-shaped pieces, which lie tangentially scattered on the surface of the +spherical calymma. Each piece is a hemispherical or flatly cap-shaped +siliceous body, often with radial striations, and with a thin solid wall. + + + +Genus 660. _Catinulus_,[278] n. gen. + +_Definition._--#Cannorrhaphida# with a skeleton composed of solid, +cap-shaped or hemispherical, not fenestrated, pieces. + +The genus _Catinulus_ differs from all the other Cannorrhaphida in the +peculiar shape of the numerous siliceous pieces, which are scattered on the +surface of the calymma and compose their rudimentary skeleton. These pieces +are neither hollow rings (as in the Dictyochida), nor hollow tubes (as in +the Cannobelida), but solid hemispherical caps or more flatly vaulted small +dishes. All the complete specimens of this genus which I observed exhibited +four equal central capsules in the spherical calymma. + + +1. _Catinulus quadrifidus_, n. sp. (Pl. 117, figs. 8, 8_a_). + +Cap-shaped pieces of the skeleton flatly vaulted, three times as broad as +high, smooth; the marginal ring with fine radial ribs and with smooth +margin. + +_Dimensions._--Diameter of the calymma 0.6 to 0.8, of the four central +capsules 0.12 to 0.2; breadth of the concave caps 0.024, height 0.008. + +_Habitat._--South Atlantic, Station 323, depth 1900 fathoms. + + +2. _Catinulus catillum_, n. sp. + +Cap-shaped pieces of the skeleton flatly vaulted, three times as broad as +high, rough, covered with numerous small spinules; the marginal ring with +stout radial ribs and a corona of denticles on the margin. + +_Dimensions._--Breadth of the concave caps 0.03, height 0.01. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +3. _Catinulus lopadium_, n. sp. + +Cap-shaped pieces of the skeleton hemispherical, twice as broad as high, +smooth; the marginal ring smooth, slightly radiate, with thickened smooth +margin. + +_Dimensions._--Diameter of the calymma 1.2, of the central capsule 0.22; +breadth of the concave caps 0.024, height 0.012. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + + +{1554}Subfamily 3. DICTYOCHIDA, Haeckel. + +_Definition._--#Cannorrhaphida# with a skeleton composed of numerous +annular pieces, which lie tangentially scattered on the surface of the +calymma. Each piece is either a simple hollow ring or a pileate and +reticulate cap, composed of a ring and several connected bars. + + + +Genus 661. _Mesocena_,[279] Ehrenberg, 1841, Abhandl. d. k. Akad. d. Wiss. +Berlin, p. 401. + +_Definition._--#Cannorrhaphida# with a skeleton composed of simple annular +pieces, each of which is a circular, elliptical or polygonal, not +fenestrated, ring, with or without radial spines. + +The genus _Mesocena_ is the simplest form of the Dictyochida, and no doubt +the common ancestral form of this subfamily. The siliceous pieces, which +are scattered in variable and indefinite number in the calymma, are simple +hollow rings, with or without spines on the periphery. Ehrenberg, who first +described and figured such rings (found fossil in different Tertiary rocks) +has mistaken them for Diatoms. Some species, which I found in the +Challenger preparations, leave no doubt that these rings are the siliceous +pieces of the skeleton of the simplest Dictyochida. They are scattered in +great numbers in the spherical calymma, which surrounds a tripylean central +capsule with all the characters of the PHAEODARIA. In the living body the +rings probably always lie in the spherical periphery of the extracapsular +jelly-veil, in tangential planes, whilst in some of the Challenger +preparations the rings were scattered in hundreds throughout the whole +jelly-mass. In a few species the rings are quite simple, circular or +elliptical, smooth, and without teeth or spines. In the majority of species +some teeth or radial spines, regularly disposed, arise from the periphery +of each ring (two, three, four to eight; sometimes sixteen, eight smaller +alternating with eight larger spines). In some species small teeth occur on +the inner margin of the rings. The number of radial spines seems to be +rather constant in all the rings of one and the same individual, with the +exception of a few variations. Thus in _Mesocena octogona_ I found here and +there single rings with seven or nine teeth, instead of the usual number +eight. Ehrenberg enumerated sixteen different species of _Mesocena_; many, +however, of these are synonymous, being founded on slight variations in the +number of the teeth; of others he has given only the name, but neither a +figure nor a description (_e.g._, _Mesocena stephanolithis_, _Mesocena +spongolithis_, &c.). + + +{1555}1. _Mesocena circulus_, Ehrenberg. + + _Mesocena circulus_, Ehrenberg, 1840, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 208. + + _Mesocena circulus_, Ehrenberg, 1854, Mikrogeol., Taf. xix. fig. 44. + +Rings of the skeleton circular, smooth or slightly denticulate on the outer +margin, without spines. This simple form is probably the ancestral form of +the Dictyochida. + +_Dimensions._--Diameter of the rings 0.02 to 0.03, thickness of the hollow +rod 0.001 or less. + +_Habitat._--Fossil in Tertiary rocks of Barbados and of the Mediterranean +(Aegina, Greece; Caltanisetta, Sicily). + + +2. _Mesocena annulus_, n. sp. + + ? _Mesocena crenulata_, Ehrenberg, 1860, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, p. 822. + +Rings of the skeleton elliptical, smooth or slightly denticulate on the +outer margin, without spines. This species is possibly identical with +_Mesocena crenulata_ of Ehrenberg, of which, however, no figure is given. +The major axis of the ellipse is one and a half times as long as the minor. + +_Dimensions._--Diameter of the rings in the major axis 0.03, in the minor +0.02; thickness of the bars 0.002. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + +3. _Mesocena diodon_, Ehrenberg. + + _Mesocena diodon_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 84. + + _Mesocena diodon_, Ehrenberg, 1854, Mikrogeol., Taf. xxxiii., Nr. xv. + fig. 18. + +Rings of the skeleton elliptical, smooth, with two opposite spines on the +poles of the major axis, which is about one and one-third as long as the +minor axis. + +_Dimensions._--Diameter of the rings in the major axis 0.04, in the minor +0.03; length of the spines 0.01. + +_Habitat._--Fossil in Barbados, and in North America (Virginia). + + +4. _Mesocena triangula_, Ehrenberg. + + _Mesocena triangula_, Ehrenberg, 1840, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 208. + + _Mesocena triangula_, Ehrenberg, 1854, Mikrogeol., Taf. xxii. fig. 41. + + _Dictyocha triangula_, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 46. + + _Lithocircus triangularis_, Stoehr, 1880, Palaeontogr., vol. xxvi. p. + 121, Taf. vii. fig. 10. + +Rings triangular, with small peripheral thorns, and three larger teeth on +the corners of the equilateral triangle. + +_Dimensions._--Diameter of the rings 0.03 to 0.05, length of the spines +0.01. + +_Habitat._--Fossil in Tertiary deposits of the Mediterranean; Caltanisetta, +Sicily (Ehrenberg, Stoehr). + + +{1556}5. _Mesocena quadrangula_, Ehrenberg. + + ? _Mesocena quadrangula_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, pp. 145, 273. + + ? _Mesocena quaternaria_, Ehrenberg, 1855, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, p. 302. + +Rings square, with four radial spines on the corners of the square. +Ehrenberg has given only the name of this species, but neither diagnosis +nor figure. I think it may be identical with the species described, which I +found in the North Atlantic. + +_Dimensions._--Diameter of the rings 0.02 to 0.025, length of the spines +0.007 to 0.01. + +_Habitat._--North Atlantic, Faeroee Channel, Gulf Stream (John Murray), +depth 600 fathoms. + + +6. _Mesocena elliptica_, Ehrenberg. + + _Mesocena elliptica_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 84. + + _Mesocena elliptica_, Ehrenberg, 1854, Mikrogeol., vol. i. Taf. xx. fig. + 44. + + _Dictyocha elliptica_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 44. + +Rings elliptical or ovate, with four peripheral spines which lie in two +diameters, perpendicular to one another, two opposite in the major, the two +others in the minor axis of the ellipse. + +_Dimensions._--Diameter of the rings 0.015 to 0.03, length of the spines +0.005. + +_Habitat._--Fossil in Tertiary rocks of the Mediterranean (Placca di furni, +from Zante, Greece); Caltanisetta, Sicily. + + +7. _Mesocena pentagona_, n. sp. + +Rings regularly pentagonal, with smooth straight bars, and with five short +and straight radial spines on the five corners. + +_Dimensions._--Diameter of the rings 0.02, length of the spines 0.005. + +_Habitat._--Fossil in Barbados. + + +8. _Mesocena hexagona_, Haeckel. + + ? _Mesocena senaria_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, pp. 163, 273. + + ? _Mesocena septenaria_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, pp. 163, 273. + +Rings regular, hexagonal, with six radial spines on the six corners +(sometimes between the usual six-radiate rings of one and the same +individual are intermingled single rings with five or seven spines). + +_Dimensions._--Diameter of the rings 0.025 to 0.03, length of the spines +0.007 to 0.01. + +_Habitat._--Mediterranean, Krim (Ehrenberg), Corfu (Haeckel). + + +{1557}9. _Mesocena octogona_, Ehrenberg. + + _Mesocena octogona_, Ehrenberg, 1841, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 417, Taf. i., Nr. iii. fig. 27. + + ? _Mesocena heptagona_, Ehrenberg, 1841, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 417, Taf. i., Nr. iii. fig. 26. + + ? _Mesocena heptagona_, Ehrenberg, 1854, Mikrogeol., Taf. xx. fig. 49. + + ? _Mesocena octoradiata_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, pp. 163, 273. + + ? _Mesocena nonaria_, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. + Berlin, pp. 163, 273. + +Rings regular, octagonal, with eight radial spines on the eight corners of +the ring (sometimes between the common octoradiate rings single rings with +seven or nine teeth are intermingled in one and the same calymma). + +_Dimensions._--Diameter of the rings 0.02, length of the spines 0.005. + +_Habitat._--Tropical Pacific; Peru, Ehrenberg; Station 272 to 274, surface. + + +10. _Mesocena bisoctona_, Ehrenberg. + + _Mesocena bisoctona_, Ehrenberg, 1845, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 78; Mikrogeol., Taf. xxxv., Nr. xviii. figs. 9, 10. + + _Mesocena binonaria_, Ehrenberg, 1845, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 78, _loc. cit._ + +Rings circular, with sixteen teeth; eight stronger teeth regularly disposed +on the outer margin, alternating with these eight smaller teeth on the +inner margin. + +_Dimensions._--Diameter of the rings 0.02, length of the outer spines +0.005. + +_Habitat._--Fossil in Guano from Peru and South Africa, also in Barbados. + + +11. _Mesocena stellata_, n. sp. (Pl. 101, fig. 9). + +Rings circular, with sixteen teeth regularly disposed on the outer margin +of the rings, eight stronger teeth alternating with eight smaller. + +_Dimensions._--Diameter of the rings 0.03, length of the larger spines +0.01. + +_Habitat._--Central area of the Pacific, Station 270, depth 2925 fathoms. + + + +Genus 662. _Dictyocha_,[280] Ehrenberg, 1838, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 128. + +_Definition._--#Cannorrhaphida# with a skeleton composed of annular pieces, +which are fenestrated by one or more arches, arising on one side of the +simple ring, but do not form a truncated pyramid (therefore no apical +ring). + +The genus _Dictyocha_ is a very remarkable and interesting form of +PHAEODARIA, which has had a curious history. Ehrenberg, who first observed +single pieces of it fossil in Tertiary rocks, supposed it to be the +siliceous carapace of a Diatom, and gave it the following {1558}diagnosis: +"Dictyocha, e familia Bacillariorum. Lorica simplex univalvis silicea, laxe +reticulata aut stellulata" (_loc. cit._). In my Monograph (1862, p. 271), I +placed it in the class Radiolaria, supposing that it might be a simple form +of Acanthodesmida, having found only isolated siliceous pieces. Afterwards +(in 1879) Richard Hertwig observed the entire living body, and demonstrated +that the hollow siliceous pieces are scattered in great numbers around a +tripylean central capsule, which exhibits all the essential characters of +PHAEODARIA (Organismus d. Radiol., 1879, p. 89). Hertwig describes the +position of the numerous siliceous pieces in the surface of the +extracapsular jelly-sphere so densely aggregated, that they touch one +another and produce the appearance of a reticulated sphere. In two +specimens, which I observed living (Pl. 101, fig. 10), and in numerous +complete specimens which I found in the collection of the Challenger, the +number of the siliceous pieces was much smaller, and they were scattered +irregularly in the surface of the alveolate jelly-sphere, being separated +by wide and unequal intervals. The regular position seems to be that the +basal rings lie tangentially in the spherical surface of the calymma, +whilst the bars of the reticulum are directed outwards, and the apical +spine radially in centrifugal direction. Very often two pieces are united +by their basal rings in such a manner that they form a little spheroidal +fenestrated body (as in _Distephanus_, Stoehr; compare p. 1550). The +characteristic reticular skeleton-pieces of _Dictyocha_ must be derived +from _Mesocena_; from its simple siliceous ring (on one side of its plane), +arise two, three, or four (rarely more) bars, which become united to a +loose framework (with two, three, or four meshes). When this network +assumes the form of a truncated pyramid (with a central mesh on the apex), +_Dictyocha_ passes over into _Distephanus_. From the corners of the +original basal ring several radial spines usually arise in a centrifugal +direction, and on the sides of these sometimes small teeth or thorns also +run in a centripetal direction. The number of the meshes and the separating +rods is usually four, more rarely two or three. The hollow rods are very +thin, either cylindrical or prismatic. As the ascending rods alternate +regularly with the corner-spines of the basal ring, we may call the latter +perradial, the former interradial. Ehrenberg has distinguished in his genus +_Dictyocha_ not less than fifty species, thirty-five living and twenty-five +fossil (ten species both living and fossil). The greater part of these +cannot be retained, as they are only slight varieties or abnormalities of +single pieces of the skeleton, such as very frequently occur associated +with the common regular forms in one and the same individual. Such abnormal +species are, _e.g._, _Dictyocha abnormis_, _Dictyocha binoculus_, +_Dictyocha bipartita_, _Dictyocha haliomma_, _Dictyocha hexathyra_, +_Dictyocha septenaria_, &c. One species (_Dictyocha splendens_), is the +fenestrated calcareous body of a Holothurian. Of some other species +Ehrenberg has only given the name, but neither a description nor a figure +(e.g., _Dictyocha borealis_, _Dictyocha cenostephania_, _Dictyocha compos_, +_Dictyocha coronata_, _Dictyocha socialis_, _Dictyocha specillum_). A +number of other species must be placed in the genera _Distephanus_ and +_Cannopilus_, so that only eight of his species of true _Dictyocha_ remain. + + +{1559}1. _Dictyocha navicula_, Ehrenberg. + + _Dictyocha navicula_, Ehrenberg, 1838, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 129; Mikrogeol., Taf. xx., Nr. i. fig. 43. + + _Dictyocha ponticulus_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, p. 267. + +Each individual ring elliptical or oblong, with one transverse arch in the +shorter axis, which bisects it into two meshes. No spines or teeth. + +_Dimensions._--Diameter of the ring 0.02, of the bars 0.001. + +_Habitat._--Fossil in Tertiary deposits, Barbados, Sicily, &c.; living in +the Atlantic, Stations 352, 354, and off Bermuda, surface. + + +2. _Dictyocha quadrata_, Ehrenberg. + + _Dictyocha quadrata_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 267. + +Each individual ring square or rhomboid, with one transverse arch in the +shorter axis, forming two meshes. Two peripheral opposite spines on the +poles of one axis. + +_Dimensions._--Diameter of the ring 0.015. + +_Habitat._--Atlantic, Bermuda Islands; fossil in Barbados. + + +3. _Dictyocha pons_, Ehrenberg. + + _Dictyocha pons_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 80; Mikrogeol., Taf. xxi. fig. 40. + + _Dictyocha tripyla_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 80; Mikrogeol., Taf. xxi. fig. 41. + +Each individual ring elliptical or oblong, with one transverse arch in the +shorter axis, forming two meshes. Four peripheral spines, on the poles of +the longer and of the shorter axis. (The individual abnormality, figured as +_Dictyocha tripyla_, _loc. cit._, Taf. xxi. fig. 41, has the transverse +arch bifid at one end, therefore three meshes result; this forms an +interesting transition to _Dictyocha fibula_.) + +_Dimensions._--Diameter of the ring 0.01, of the bars 0.001. + +_Habitat._--Fossil in Tertiary rocks, Oran, Africa. + + +4. _Dictyocha triommata_, Ehrenberg. + + _Dictyocha triommata_, Ehrenberg, 1845, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 76; Mikrogeol., Taf. xxxiii., Nr. xv. fig. 11. + + _Dictyocha triactis_ (= _triacantha_), Ehrenberg, 1844, Monatsber. d. k. + preuss. Akad. d. Wiss. Berlin, p. 80. + + _Dictyocha trifenestrata_, Ehrenberg, 1841, Monatsber. d. k. preuss. + Akad. d. Wiss. Berlin, p. 410; Mikrogeol., Taf. xix. fig. 38. + + _Dictyocha abyssorum_, Ehrenberg, 1854, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 38. + +Each pileated piece of the skeleton is a small three-sided pyramid, the +sides of which form three triangular meshes; the three edges between them +are three curved interradial beams, united in the {1560}centre (the apex of +the pyramid). Alternating with these, three horizontal, perradial, +centrifugal spines start from the base. + +_Dictyocha trigona_, Zittel, 1876 (L. N. 29, p. 83, Taf. ii. fig. 6), is an +interesting Cretaceous species, perhaps a variety of _Dictyocha triommata_. + +_Dimensions._--Diameter of the basal triangle 0.01, of the three meshes +0.005. + +_Habitat._--Fossil in different Tertiary deposits (of Sicily, Greece, North +America); living in the Central Pacific, Stations 270 to 272, depth 2600 to +2925 fathoms. + + +5. _Dictyocha tripyla,_ Ehrenberg. + + _Dictyocha tripyla,_ Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 80. + + _Dictyocha tripyla,_ Ehrenberg, 1854, Mikrogeol., Taf. xix. fig. 38 (et + Taf. xxi. fig. 41?). + +Each pileate piece of the skeleton is a small three-sided pyramid, similar +to that of _Dictyocha triommata_, but differs from it in the possession of +three small perpendicular teeth, which are directed downwards and start +from the basal ring near the origin of the three horizontal spines. + +_Dimensions._--Diameter of the triangular basal ring 0.015, of the three +meshes 0.007. + +_Habitat._--Fossil in Tertiary deposits. North Africa (Oran), Sicily +(Caltanisetta). + + +6. _Dictyocha medusa_, n. sp. (Pl. 101, figs. 13, 14). + +Each pileated piece of the skeleton has four equal, cruciate, triangular +meshes. From the four corners of the square basal ring proceed four +perradial horizontal spines, and between these four interradial curved +bars, which correspond to the edges of a four-sided pyramid, arise from the +centre of the four sides and become united in the centre (on the apex of +the pyramid). No apical spine. + +_Dimensions._--Diameter of the basal ring 0.02, of the four meshes 0.01. + +_Habitat._--Central area of the Pacific, Station 272, depth 2600 fathoms. + + +7. _Dictyocha staurodon_, Ehrenberg. + + _Dictyocha staurodon,_ Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 80. + + _Dictyocha staurodon,_ Ehrenberg, 1854, Mikrogeol., Taf. xviii. fig. 58. + +Each pileated piece of the skeleton is a small, regular, four-sided +pyramid, similar to the foregoing species. It differs from _Dictyocha +medusa_ in the development of a vertical apical spine, and of four small +centripetal teeth, which start from the inside of the basal square, between +the four perradial spines and the four ascending interradial beams. + +_Dimensions._--Diameter of the basal ring 0.025, of the meshes 0.01. + +_Habitat._--Fossil in Tertiary rocks; Tripel of Richmond, Virginia +(Ehrenberg); Barbados, (Haeckel); living in the Tropical Atlantic, Station +347, surface. + + +{1561}8. _Dictyocha fibula_, Ehrenberg. + + _Dictyocha fibula_, Ehrenberg, 1839, Abhandl. d. k. Akad. d. Wiss. + Berlin, p. 149; Mikrogeol., Taf. xviii. fig. 54, _a_, _b_, _c_, Taf. xix. + fig. 43, Taf. xx. fig. 45, Taf. xxi. fig. 42, &c. + + _Dictyocha abnormis_, Ehrenberg, 1845, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 76; Mikrogeol., 1854, Taf. xxxvA., Nr. xvii. fig. 9. + + _Dictyocha bipartita_, Ehrenberg, 1854, Mikrogeol., Taf. xxii. fig. 44. + + _Dictyocha tenella_, Ehrenberg, 1841, Abhandl. d. k. Akad. d. Wiss. + Berlin, Taf. ii. fig. 11. + +Each pileated piece of the skeleton stirrup-shaped, with two pairs of +meshes, and a square basal ring, the four corners of which are prolonged +into four perradial spines. Between the latter four interradial beams arise +from the sides in pairs, and the two pairs are connected by a diagonal +arch. Therefore the two opposite meshes are larger and pentagonal, the +other two meshes (alternating with these) are smaller and square. No +vertical spine on the apex. + +_Dimensions._--Diameter of the basal square ring (diagonal) 0.01 to 0.02, +of the meshes 0.005. + +_Habitat._--Fossil in different Tertiary rocks (Barbados, Oran, Greece, +Sicily, &c.), Ehrenberg. + + +9. _Dictyocha messanensis_, Haeckel. + + _Dictyocha messanensis_, Haeckel, 1862, Monogr. d. Radiol., p. 272, Taf. + xii. figs. 3-6. + + _Dictyocha fibula_, R. Hertwig (not Ehrenberg), 1879, Organismus d. + Radiol., p. 89, Taf. ix. fig. 5. + +Each pileated piece of the skeleton stirrup-shaped, very similar to +_Dictyocha fibula_, but distinguished by a vertical apical spine in the +centre of the transverse arch, which connects the two pairs of ascending +bars. + +_Dimensions._--Diameter of the basal ring 0.02 to 0.03, of the meshes 0.01 +to 0.016. + +_Habitat._--Mediterranean (Messina), North Atlantic (Canary Islands), +Station 354, surface. + + +10. _Dictyocha epiodon_, Ehrenberg. + + _Dictyocha epiodon_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 79; Mikrogeol., Taf. xviii. fig. 55. + +Each pileated piece of the skeleton stirrup-shaped, with four paired meshes +similar to the hats of _Dictyocha fibula_, but distinguished by four small +centripetal thorns, which start from the inside of the basal ring, at the +side of the four ascending beams. No apical spine. + +_Dimensions._--Diameter of the basal ring 0.03, of the meshes 0.01. + +_Habitat._--Fossil in Tertiary rocks of North America (Miocene Tripel of +Richmond, Virginia, &c.). + + +11. _Dictyocha stapedia_, n. sp. (Pl. 101, figs. 10-12). + +Each pileated piece of the skeleton stirrup-shaped, with four paired +meshes, similar to the hats of _Dictyocha fibula_ and _Dictyocha +messanensis_, but distinguished by four small centripetal teeth, which +start from the inside of the basal ring, at the side of the four ascending +beams. In the centre of the diagonal arch arises a vertical apical spine +(differing from _Dictyocha epiodon_). This species seems {1562}to be the +most common of the living forms and widely distributed over all warmer +seas. I observed in Ceylon, taken on the surface, the living specimen +figured in Pl. 101, fig. 10, the numerous spicula were irregularly +scattered over the spherical surface of the alveolate calymma. Other +specimens occur in various preparations of the Challenger collection, from +the Atlantic and the Pacific. The majority of the siliceous little hats +exhibited the stirrup-form shown in fig. 11, and many were united in pairs, +forming a twin-piece (fig. 12). Intermingled with these are found some +irregular forms, representing the specific form of some allied species, +viz., _Dictyocha speculum_, _Dictyocha staurodon_, _Dictyocha epiodon_ and +_Dictyocha messanensis_. + +_Dimensions._--Diameter of the basal ring 0.015 to 0.03, of the meshes +0.005 to 0.012. + +_Habitat._--Cosmopolitan; Atlantic, Pacific, Indian Ocean, in the Tropical +and warmer regions; Stations 159, 244, 266-272, 318, 352, &c. + + +12. _Dictyocha rhombus_, n. sp. + +Each pileated piece of the skeleton stirrup-shaped, similar to _Dictyocha +stapedia_, with four paired meshes. It differs from the latter in the +rhomboid form of the basal ring and the larger size of the two opposite +meshes, which are two to three times as large as the two others. Therefore +the four centripetal teeth of the basal ring do not stand in the four +single meshes, but in pairs only in the two larger meshes. + +_Dimensions._--Diameter of the basal ring 0.02, of the meshes 0.005 to +0.01. + +_Habitat._--North Atlantic; Faeroee Channel, Gulf Stream, depth 50 to 600 +fathoms, John Murray. + + + +Genus 663. _Distephanus_,[281] Stoehr, 1880, Palaeontogr., vol. xxvi. Taf. +ii. p. 121. + +_Definition._--#Cannorrhaphida# with a skeleton composed of pileated +pieces, each of which is a small truncated pyramid with one girdle of +meshes (the apical ring being simple). + +The genus _Distephanus_ was founded in 1880 by Stoehr (_loc. cit._) for a +single twin-piece of the skeleton of _Dictyocha speculum_. Among the common +fossil forms of this species he once found in the Tertiary rocks of +Caltanisetta, Sicily, a single piece (_loc. cit._, Taf. vi. fig. 9), which +seemed to be composed of two equal pieces so united that they formed a +little sphere with fourteen meshes; on each pole of the sphere lies a +central hexagonal mesh surrounded by six pentagonal meshes, and from the +six corners of the equatorial ring arise six centrifugal spines. No doubt +this was a mistake, and the apparent little sphere was one of the above +mentioned twin-forms, composed of two separate hexagonal truncated +pyramids, which were loosely connected by their basal rings. I have often +seen such twin-pieces of _Dictyocha speculum_ and of other species (Pl. +101, fig. 12, Pl. 114, fig. 8), and was always able to separate the two +loosely connected halves of the bivalve shell by slight compression. + +{1563}The genus _Distephanus_ of Stoehr, therefore, is nothing other than +the _Dictyocha_ of Ehrenberg. But I think it is more convenient to retain +the name _Distephanus_ for those forms of _Dictyocha_ which possess a +simple apical mesh surrounded by a ring of lateral meshes, and in which +each piece of the skeleton forms a small truncated pyramid. The basal plane +of this pyramid is marked by the original basal ring (_Mesocena_), the +truncated upper plane by the parallel apical ring, and the edges of the +pyramid by the rising bars which connect both rings. In this sense, so far +as the two rings lying in parallel planes are concerned, the term +_Distephanus_ is correct (but not in the original sense of Stoehr). The +number of the rising bars between the two rings varies from four, five, six +to eight or more. It seems rather constant in each species, so that all the +pieces of the skeleton of one specimen possess either four or six or eight +lateral meshes, &c. But sometimes individual irregularities occur. In the +majority of species each skeleton-piece is armed with spines. Usually a +radial horizontal spine starts centrifugally from each corner of the basal +ring, and on the side of this a small tooth or thorn often starts +centripetally or downwards. In the twin-pieces, where the two basal rings +are united, these teeth catch into one another. In some species upper +spines also occur, starting from the corners of the apical ring. The +perradial spines of the corners of the basal ring alternate regularly with +the interradial ascending bars, which bisect the sides of the ring, as in +_Dictyocha_. + + +1. _Distephanus crux_, Haeckel. + + _Dictyocha crux_, Ehrenberg, 1840, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 207; Mikrogeol., 1854, Taf. xviii. fig. 56, Taf. xx. + fig. 46, Taf. xxxiii. Nr. xv. fig. 9. + + _Dictyocha bipartita_, Ehrenberg, 1844, _loc. cit._, p. 79, Taf. xxii. + fig. 44. + +Each pileated piece of the skeleton exhibits four pentagonal lateral meshes +around one square central mesh, and is composed of two horizontal square +rings; the smaller upper square is connected with the larger lower square +by four ascending interradial beams, which start from the corners of the +former and bisect the sides of the latter; from the corners of the basal +ring arise four short perradial spines. + +_Dimensions._---Diameter of the basal ring 0.02 to 0.03, of the apical ring +0.008. + +_Habitat._---Tropical Atlantic, Station 347, surface; fossil in Tertiary +deposits of the Mediterranean (Sicily, Oran). + + +2. _Distephanus mesophthalmus_, Haeckel. + + _Dictyocha mesophthalma_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, p. 80; Mikrogeol., 1854, Taf. xxii. fig. 43. + +Each pileated piece of the skeleton exhibits four lateral meshes around the +central mesh, and is composed of two parallel horizontal square rings, like +those of _Distephanus crux_, but distinguished {1564}from this by eight +short teeth, four centripetal on the larger lower ring and four perradial +centrifugal on the smaller upper ring. + +_Dimensions._--Diameter of the basal ring 0.03, of the apical ring 0.015. + +_Habitat._--Fossil in Tertiary rocks of Sicily, Caltanisetta (Ehrenberg); +living in the Central Pacific, Station 270 to 272, surface. + + +3. _Distephanus stauracanthus_, Haeckel. + + _Dictyocha stauracanthus_, Ehrenberg, 1845, Monatsber. d. k. preuss. + Akad. d. Wiss. Berlin, p. 76; Mikrogeol., 1854, Taf. xxxiii., Nr. xv. + fig. 10. + +Each pileated piece of the skeleton exhibits four lateral meshes around the +central mesh, and is composed of two horizontal rings, which are connected +by four perradial beams arising from the corners of the upper and smaller +square ring. Lower ring octagonal, with eight peripheral adradial spines, +and with four interradial centripetal teeth on the inside. + +_Dimensions._--Diameter of the basal ring 0.03, of the apical ring 0.004. + +_Habitat._--Fossil in Tertiary rocks of North America (Hollis Cliff, +Virginia; Norwich, Connecticut). + + +4. _Distephanus asteroides_, n. sp. + + _Dictyocha asteroides_, Haeckel, 1881, Prodromus. + +Each pileated piece of the skeleton exhibits five lateral meshes around the +central mesh (or the upper ring). Five peripheral spines (on the corners of +the lower ring) simple, not articulated. + +_Dimensions._--Diameter of the basal ring 0.02, of the apical ring, 0.007. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +5. _Distephanus pentasterias_, Haeckel. + + _Dictyocha pentasterias_, Ehrenberg, 1839, Mikrogeol., Taf. xviii. fig. + 61. + + ? _Dictyocha quinaria_, Ehrenberg, 1842, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, p. 265. + + ? _Dictyocha elegans_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 80; Mikrogeol., 1854, Taf. xxii. fig. 51. + + _Actiniscus elegans_, Ehrenberg, 1854, Mikrogeol., Taf. xxii. fig. 51. + +Each pileated piece of the skeleton exhibits five lateral meshes around the +central mesh (or the upper ring). Five peripheral spines (on the corners of +the lower ring) articulated, triangular, with three distinct joints +(tapering towards the distal end). + +_Dimensions._--Diameter of the basal ring 0.012 to 0.018, of the apical +ring 0.002 to 0.003. + +_Habitat._--Cosmopolitan; living in the depths of the Atlantic and Central +Pacific, Stations 247, 270 to 272, depths 2530 and 2600 to 2925 fathoms; +fossil in Tertiary deposits (Tripel of Caltanisetta, Sicily; Richmond, +Virginia). + + +{1565}6. _Distephanus speculum_, Haeckel. + + _Dictyocha speculum_, Ehrenberg, 1837, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 150; Mikrogeol., 1854, Taf. xviii. fig. 57, Taf. xix. + fig. 41, Taf. xxi. fig. 44, Taf. xxii. fig. 47, &c. + + _Dictyocha speculum_, Stoehr, 1880, Palaeontogr., vol. xxvi., Taf. vii. + fig. 8. + + _Dictyocha anacantha_, Ehrenberg, 1854, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 238. + + _Dictyocha diommata_, Ehrenberg, 1854, Mikrogeol., Taf. xxxiii., Nr. + xvii. fig. 6. + + _Dictyocha erebi_, Ehrenberg, 1854, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 238. + + _Dictyocha haliomma_, Ehrenberg, 1844, Mikrogeol., 1854. Taf. xxi. fig. + 46. + + _Dictyocha hexathyra_, Ehrenberg, 1844, Mikrogeol., 1854, Taf. xxii. fig. + 46. + + _Dictyocha ubera_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 80. + + _Dictyocha stella_, Ehrenberg, 1854, Mikrogeol., Taf. xxii. fig. 52. + + _Dictyocha rotundus_, Stoehr, 1880, Palaeontogr., vol. xxvi., Taf. vii. + fig. 9. + +Each pileated piece of the skeleton is a truncated, six-sided pyramid, and +composed of two regular hexagonal rings which lie in parallel plains, and +are connected by six ascending interradial beams; these start from the +corners of the upper smaller ring and bisect the sides of the lower larger +ring; from the corners of the latter start six perradial centrifugal +spines. + +_Dimensions._--Diameter of the basal ring 0.03, of the apical ring 0.01. + +_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Indian, Pacific; fossil +in Barbados, Sicily, &c. + + +7. _Distephanus ornamentum_, Haeckel. + + _Dictyocha ornamentum,_ Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, p. 80; Mikrogeol., 1854, Taf. xxii. fig. 49. + + _Dictyocha binoculus_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 79; Mikrogeol., 1854, Taf. xix. fig. 42. + +Each pileated piece of the skeleton is a truncated, six-sided pyramid, +similar to that of _Distephanus speculum_, but distinguished by six small +(probably vertical) teeth, which start from the inside of the lower +(larger) ring, on the sides of the ascending beams. + +_Dimensions._--Diameter of the basal ring 0.03, of the apical ring 0.015. + +_Habitat._--Fossil in Tertiary deposits of Sicily, Caltanisetta +(Ehrenberg). + + +8. _Distephanus aculeatus_, Haeckel. + + _Dictyocha aculeata_, Ehrenberg, 1839, Abhandl. d. k. preuss. Akad. d. + Wiss. Berlin, p. 149; Mikrogeol., 1854, Taf. xxii. Fig. 48, Taf. xix. + fig. 40. + + _Dictyocha aculeata_, Stoehr, 1880, Palaeontogr., vol. xxvi. p. 120, + Taf. vii. fig. 7. + + _Dictyocha bisternaria_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, p. 201. + +Each pileated piece of the skeleton is a truncated, six-sided pyramid, +similar to that of _Distephanus speculum_, but distinguished by six small +perradial, horizontal teeth, which start from the sides of the upper +(smaller) ring. + +_Dimensions._--Diameter of the basal ring 0.02, of the apical ring 0.008. + +_Habitat._--Fossil in Tertiary deposits of the Mediterranean; plastic clay +of Greece and Sicily; living in the Mediterranean and the Atlantic, Station +352, surface. + + +{1566}9. _Distephanus sirius_, Haeckel. + + _Actiniscus sirius_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 68. + + _Dictyocha sirius_, Ehrenberg, 1854, Mikrogeol., Taf. xviii. fig. 59. + +Each pileated piece of the skeleton is a truncated six-sided pyramid, +similar to that of _Distephanus speculum_, but distinguished by the six +broad, triangular, peripheral spines, which are articulated and connected +by a thin siliceous membrane (like a web-membrane); each spine has three +articulations (as in _Dictyocha pentasterias_). + +_Dimensions._--Diameter of the basal ring 0.02, of the apical ring 0.005. + +_Habitat._--Fossil in Tertiary rocks (Richmond, Virginia), but also living +in the Atlantic Ocean, Gulf Stream, Faeroee Channel, John Murray, 1880. + + +10. _Distephanus corona_, n. sp. (Pl. 114, figs. 7-9). + + _Dictyocha corona_, Haeckel, 1881, Prodromus. + +Each pileated piece of the skeleton is a truncate six-sided pyramid like +that of _Distephanus speculum_, but differing in the number (twenty-four) +of teeth or spines. Six interradial ascending beams connect the two +horizontal rings between these, and six nearly vertical spines arise from +the perradial corners of the upper hexagonal ring. In the same meridional +(perradial) plains six larger spines descend downwards from the corners of +the lower larger ring. Between these six descending spines and the six +ascending beams arise from the upper edge of the lower ring twelve shorter +teeth of unequal size (the right tooth in each pentagonal lateral mesh +being smaller and directed upwards, the left tooth being larger and +directed nearly horizontally outwards). The lower ring is nearly +dodecagonal. + +_Dimensions._--Diameter of the basal ring 0.025 to 0.03, of the apical ring +0.012 to 0.02. + +_Habitat._--North-west Pacific, Sea of Japan, Station 231, depth 2250 +fathoms. + + +11. _Distephanus octonarius_, Haeckel. + + _Dictyocha octonaria_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 201. + + _Dictyocha polyactis_, Ehrenberg, 1844, _loc. cit._, p. 80; Mikrogeol., + 1854, Taf. xxii. fig. 50. + + _Dictyocha septenaria_, Ehrenberg, 1844, _loc. cit._, p. 80; Mikrogeol., + 1854, Taf. xxi. fig. 45. + +Each pileate piece of the skeleton is a truncated eight-sided pyramid, +composed of two regular octagonal rings, which lie in parallel plains, and +are connected by eight radial beams. From the eight outer corners of the +lower ring (or from the eight interradial meshes, between the eight +perradial beams) start eight basal centrifugal spines. (This species is +similar to _Distephanus speculum_, but has eight beams instead of six. In +single pieces the number of the beams and meshes varies between seven and +nine, the constant number being eight.) A seven-rayed variety is _Dictyocha +septenaria_ (_loc. cit._), a nine-rayed _Dictyocha polyactis_. + +_Dimensions._--Diameter of the basal ring 0.02 to 0.03, of the apical ring +0.01 to 0.015. + +_Habitat._--Fossil in Tertiary rocks (Tripel and Marne from Caltanisetta, +Sicily; Oran, Africa); living in the depths of the Atlantic, Station 348, +and Pacific, Station 270, &c. + + +{1567}12. _Distephanus octogonius_, n. sp. + + _Dictyocha septenaria_, Ehrenberg, 1854, Mikrogeol., Taf. xxxvA., Nr. + xxi. fig. 8. + +Each pileated piece of the skeleton is a truncated eight-sided pyramid, +like that of _Distephanus octonarius_, but differs from it by having eight +short erect teeth, which arise from the corners of the upper smaller ring +and lie in the same perradial plains as the eight horizontal spines +starting from the corners of the lower larger ring. Ehrenberg has figured +only an individual abnormality with seven beams instead of eight, taken +from the Antarctic ice; but I found the same form frequent in deep-sea +soundings from the Antarctic, almost constantly with eight beams, isolated +hats with six, seven, or nine beams being intermingled. + +_Dimensions._--Diameter of the basal ring 0.02, of the apical ring 0.012. + +_Habitat._--Antarctic Ocean; in smolten "Pancake-Ice," taken by Sir James +Clark Ross in lat. 78d 10' S., long. 162d W. (Ehrenberg); Station 156, +depth 1975 fathoms. + + +13. _Distephanus diadema_, n. sp. + + _Dictyocha diadema_, Haeckel, 1881, Prodromus. + +Each pileated piece of the skeleton is an eight-sided pyramid, like that of +the two foregoing species, but differing in the number and distribution of +the teeth or spines, which are thirty-two. From the eight corners of the +basal ring start eight long, nearly horizontal perradial spines, which bear +on each side a smaller, nearly vertically descending spine. From the eight +corners of the upper ring ascend also eight perradial spines, alternating +with the eight interradial beams, which connect the two rings. + +_Dimensions._--Diameter of the basal ring 0.04, of the apical ring 0.02. + +_Habitat._--South Pacific, Station 293, depth 2025 fathoms. + + + +Genus 664. _Cannopilus_,[282] n. gen. + +_Definition._--#Cannorrhaphida# with a skeleton composed of pileated +pieces, each of which is a small truncated pyramid with two girdles of +meshes (the apical ring being fenestrated). + +The genus _Cannopilus_ represents the most highly developed form of +Dictyochida. Each piece of the skeleton is a little fenestrated hat or +topped pyramid, as in _Distephanus_. But the apical mesh is simple in the +latter, in the former it is divided into several meshes by bars which start +in a centripetal direction from the upper ring. Therefore we find two +annular rows of meshes, one above the other; an apical or upper row of +smaller meshes and a basal or lower row of larger meshes. In the apex of +the little {1568}hat is either a central mesh or an apical spine. Other +spines arise from the basal ring, as in the former genera. The number of +corner-spines on the basal ring is either four, six, or eight (in +individual abnormalities also five or seven). + + +1. _Cannopilus superstructus_, Haeckel. + + _Dictyocha superstructa_, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, p. 80; Mikrogeol., Taf. xxii. fig. 45. + +Each pileated piece of the skeleton is a reticulated four-sided pyramid. +The base of it (or the lower ring) is a square, from the four perradial +corners of which start four centrifugal horizontal spines. In the centres +of the four basal bars (or the sides of the square) arise four interradial +beams, which unite in the second (or upper) square ring. This latter forms +a second (but much smaller) four-sided pyramid, the apex of which is +truncated. Therefore the little hat bears nine meshes; around the large +central opening four upper smaller and four lower larger quadrangular +meshes. + +_Dimensions._--Diameter of the basal ring 0.03, of the apical ring 0.01. + +_Habitat._--Fossil in Tertiary rocks of Sicily (Caltanisetta). + + +2. _Cannopilus diplostaurus_, n. sp. (Pl. 114, fig. 10). + +Each pileated piece of the skeleton is a truncated quadrangular pyramid. +From the corners of the square basal ring start four perradial, nearly +horizontal, spines. Between these arise four interradial beams, which are +united above by an upper square ring. This latter is divided into four +small square meshes by a regular cross of perradial bars, the distal ends +of which are prolonged into four short ascending spines. In the centre of +the cross arises a vertical apical spine. + +_Dimensions._--Diameter of the basal ring 0.04, of the apical ring 0.016. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +3. _Cannopilus calyptra_, Haeckel. + + _Dictyocha heptacanthus_, Ehrenberg, 1840, Monatsber. d. k. preuss. Akad. + d. Wiss. Berlin, p. 208; Mikrogeol., 1854, Taf. xix. fig. 39 (?). + +Each pileated piece of the skeleton is a truncated six-sided pyramid, like +that of _Dictyocha speculum_, but distinguished by the reticulation of the +upper (smaller) ring, which is divided by six beams into six meshes, lying +in the horizontal plane of the upper ring. Six peripheral spines on the +corners of the lower ring. (The irregular form, figured by Ehrenberg as +_Dictyocha heptacanthus_, _loc. cit._, is probably only an individual +abnormality with seven peripheral spines, instead of six; similar +abnormalities occur also among the regular hexagonal forms which I found in +the Tertiary rocks of Caltanisetta (Sicily). + +_Dimensions._--Diameter of the basal ring 0.05, of the apical ring 0.02. + +_Habitat._--Fossil in Tertiary deposits of Greece and Sicily. + + +{1569}4. _Cannopilus hemisphaericus_ (Haeckel). + + _Dictyocha hemisphaerica_, Ehrenberg, 1844, Monatsber. d. k. preuss. + Akad. d. Wiss. Berlin, p. 266. + +Each pileated piece of the skeleton is nearly hemispherical, with thirteen +meshes; six lower and larger meshes in the sides of the truncated six-sided +pyramid, seven others in the convex surface of the upper ring (one central +with six surrounding it). From the six corners of the lower ring arise six +horizontal perradial spines. From the inside of the same ring (probably on +the side of the six ascending interradial beams) spring six centripetal +teeth. + +_Dimensions._--Diameter of the basal ring 0.02, of the apical ring 0.01. + +_Habitat._--North Atlantic; Bermuda (Bailey). + + +5. _Cannopilus cyrtoides_, n. sp. (Pl. 114, figs. 11, 12). + + _Dictyocha cyrtoides_, Haeckel, 1881, Prodromus. + +Each pileated piece of the skeleton is an eight-sided truncated pyramid, or +nearly hemispherical. From the basal ring arise twenty-four thorns or +teeth, eight longer perradial centrifugal teeth placed almost horizontally, +and between these sixteen shorter adradial teeth, directed downwards and +somewhat centripetally. The network of the small hat is composed of +seventeen meshes, arranged in two rows. The eight lower meshes are +hexagonal, separated by six interradial ascending beams, and twice as large +as the eight upper pentagonal meshes, which are separated by eight +perradial beams, and enclose an apical central mesh. + +_Dimensions._--Diameter of the basal ring 0.04, of the apical ring 0.005. + +_Habitat._--Central area of the Pacific, Station 266, depth 2750 fathoms. + + + +Family LXXIII. #AULACANTHIDA#, Haeckel (Pls. 102-105). + + _Aulacanthida_, Haeckel, 1862, Monogr. d. Radiol., p. 262. + +_Definition._--PHAEODARIA with an incomplete skeleton, composed of numerous +hollow radial tubes, which pierce the spherical calymma and touch with +their proximal ends the surface of the tripylean central capsule. + +The family #Aulacanthida# represents a large and interesting group of +PHAEODARIA, differing from all other families of this legion in the +possession of numerous large radial tubes, which pierce the gelatinous and +alveolated calymma in a radial direction, and come in contact with the +outer surface of the central capsule by their inner or proximal ends, +whilst their outer or distal ends project over the surface of the spherical +calymma, and develop a great variety of manifold branches and terminal +appendages. Usually (with the exception of a single genus only) the surface +of the calymma is covered by an {1570}arachnoidal veil or mantle, composed +of thousands of very fine, hollow, tangential needles. The skeleton +therefore is incomplete, without any direct connection between the isolated +pieces, just as in the preceding Cannorrhaphida, but the latter never +possess the large, hollow, cylindrical, radial tubes, which are +characteristic of all Aulacanthida. + +The spherical body of the Aulacanthida has usually a diameter of 1 to 2 +mm., and including the radial tubes, of 4 to 5 mm. or more. Some species +are very common and cosmopolitan, and some genera contain numerous species, +distributed widely over all oceans. In spite of their considerable size and +wide distribution, only one species of this great family has been hitherto +known, having been discovered by me at Messina in 1859, and described in my +Monograph as _Aulacantha scolymantha_ (1862, p. 263, Taf. ii. figs. 1, 2, +and Taf. iv. figs. 1-5). I there founded for it the peculiar subfamily +Aulacanthida, and annexed it to the Thalassicollida. The same cosmopolitan +species has been subsequently observed at Messina by R. Hertwig, who first +recognised the three openings in its central capsule, and therefore united +it with his TRIPYLEA (Organism. d. Radiol., 1879, p. 88, Taf. ix. figs. 3, +4; Taf. x. figs. 7, 10). The rich collection of the Challenger has added an +astonishing number of new and interesting forms of Aulacanthida, so that I +can describe here not less than six genera and fifty-eight species. The +majority are inhabitants of the colder parts of the South Pacific and South +Atlantic, at great depths, whilst a few species only are found in the +tropics. + +The structure of the body in all Aulacanthida seems to be similar in all +important points, and the differences by which we are enabled to separate +this great number of species are mainly produced by differences in the +development of the radial tubes, their form and their polymorphous +apophyses. The entire body represents a rather firm jelly-sphere of 1 to 2 +mm. diameter (rarely less or more); the peripheral layer of the spherical +calymma is rather clear and transparent, whilst its central part is dark +and opaque, containing the big phaeodium and the enclosed central capsule. +The diameter of the latter is usually between 0.1 and 0.3, often 0.4 to +0.5, or even more. The gelatinous calymma, in the centre of which the +capsule is placed, always contains numerous, large, spherical or roundish +alveoles, similar to those of _Thalassicolla_, and between them a delicate +network of sarcode (Pl. 102, fig. 1; Pl. 103, fig. 1; Pl. 104, fig. 1). + +The spherical surface of the calymma is nearly always protected by that +characteristic arachnoidal veil or mantle, which is composed of thousands +of very fine tangential needles, densely interwoven in all tangential +directions but never directly connected. They are wanting in a single genus +only, in _Aulactinium_ (Pl. 101, figs. 6-8). This genus, therefore, may +represent a separate subfamily, the Aulactinida, whilst all other genera +protected by that mantle constitute the subfamily Aulographida. The +tangential needles always seem to have the same shape as I have accurately +described, in 1862, of _Aulacantha scolymantha_. They are constantly +smooth, very thin and fragile, but also very elastic cylinders of silica, +of equal breadth throughout their whole length, and seem {1571}to be open +at both ends, since they are easily and constantly filled by air when +dried. Their length is usually between 0.2 and 0.3 mm., rarely less than +0.15 or more than 0.5; their diameter is always less than 0.001, usually +less than 0.0005. + +The large radial tubes of the Aulacanthida constitute the most +characteristic structures of this family, and are always so placed that +their inner or proximal ends are in loose contact with the outer surface of +their central capsule (upon which they rest), whilst their outer or distal +ends are more or less prominent over the spherical surface of the calymma. +Their position, therefore, is rather loose and movable, since they are +fixed only by the consistence of the jelly of the surrounding calymma, and +on the surface of the latter by the covering veil or the mantle of +tangential needles (compare Pl. 102, fig. 1; Pl. 103, fig. 1; Pl. 104, fig. +1). Their number seems never to be fixed, and is probably very variable in +different species. I found, in 1859, in the common _Aulacantha +scolymantha_, the number varying from thirty to one hundred and fifty +(_loc. cit._, p. 264). So also in _Aulographis pandora_, _Aulospathis +variabilis_, and some other common species, numerous specimens of which I +could compare, I found their number very variable, being in one and the +same species sometimes only from ten to twenty, at other times from fifty +to eighty, and sometimes even from one hundred to one hundred and fifty or +more. Perhaps the number increases with the age and the increasing size of +the calymma. + +The radial tubes are always cylindrical (circular in transverse section), +never angular or prismatic. Usually they are straight, more rarely slightly +curved (Pl. 105, figs. 1, 2; Pl. 101, fig. 6). The cylinders are usually +more or less tapering towards both ends, sometimes even spindle-shaped; the +inner or proximal end is always simple and rounded, often slightly swollen +or inflated, and ovate; the outer or distal end is often thickened, +club-shaped, and exhibits the greatest variety in form and ramification. +The length of the radial tubes is usually from 1 to 3 mm., rarely less than +0.8, or more than 3.2; their diameter is usually between 0.02 and 0.03, +rarely less than 0.01 or more than 0.05. The smallest radial tubes are +found in _Aulactinium_, the largest in _Aulospathis_. + +The siliceous wall of the cylindrical radial tubes is usually very thin, +fragile, and perfectly structureless. Only in a few species, mainly of +_Aulographis_, does the wall become very thick and composed of concentric +cylindrical layers (Pl. 105, figs. 6-11). Their cavity is wide and simple, +and filled up by jelly (not by sarcode, as I supposed in my first +description). The simple cavity of the tubes, though not smaller than in +the radial tubes of the Aulosphaerida, Circoporida and Tuscarorida, never +contains the characteristic axial filament with its branches, which is +constantly found in the latter families. According to the description of R. +Hertwig, the tubes are perfectly closed and have no opening. I suppose, +however, that a small opening always exists in the centre of the rounded +base, and perhaps a second on the distal apex. Otherwise the circumstance +that the entire and well-preserved tubes become easily and constantly +filled {1572}up by air, when purified by hot mineral acids and afterwards +dried, cannot be explained. I suppose that the jelly contained in the +cavity of the tubes remains in constant connection by these openings with +the jelly of the surrounding calymma. + +The distal ends of the radial tubes exhibit in the Aulacanthida the +greatest variety in the production of different branches and capturing +apparatus, and this serves for the distinction of the genera and subgenera +here described. In two genera only (in _Aulactinium_ Pl. 101, figs. 6-8; +and in _Aulacantha_, Pl. 105, fig. 16), the distal ends are simple, not +branched. In the four other genera they are armed with terminal branches, +which are usually arranged in elegant verticils. The greatest variety in +the formation of these verticils is developed in _Aulographis_ (Pl. 103). +The single branches of the terminal verticils are here simple, whilst in +the closely allied _Auloceros_ they are forked or elegantly ramified (Pl. +102). _Aulospathis_, the biggest of all Aulacanthida, is distinguished by +the possession of a verticil of lateral branches, placed beyond the +terminal verticil, immediately above the veil of tangential needles (Pl. +104). _Aulodendron_, finally, possesses lateral and terminal branches, +which are irregularly scattered. + +The branches of the radial tubes are rarely straight, usually more or less +curved, either simple or again ramified. Their surface is either smooth or +armed with small spines or recurved teeth, often elegantly dentated or +serrated (Pl. 103, figs. 20-27; Pl. 105, figs. 7-13). Their distal ends are +either simply pointed or armed with a spathilla, or a small crown of +verticillate, usually recurved teeth (Pl. 104, figs. 4-17). The variety and +elegance of these minute armatures are very interesting, the more so as +they occur in very similar and analogous forms among the Aulosphaerida, the +Coelographida, and other PHAEODARIA. + +The _central capsule_ of the Aulosphaerida and its large nucleus +("Binnenblaeschen"), as well as the surrounding alveolate calymma +("Alveolen-Huelle"), and the enclosed dark phaeodium ("dunkels Pigment") +were first described in my Monograph (1862, _loc. cit._, p. 362). Their +minute structure has been examined afterwards very accurately by R. Hertwig +(1879, _loc. cit._, p. 95). The numerous well-preserved preparations of the +Challenger (stained with carmine and preserved in glycerine) which I could +examine, confirmed in all respects the detailed description of Hertwig +(compare Pl. 102, fig. 1; Pl. 103, fig. 1; Pl. 104, fig. 1). + +The spherical or subspherical central capsule is usually slightly depressed +in the shortened main axis. Its diameter is usually between 0.1 and 0.3, +rarely less than 0.08 or more than 0.4 mm. Its outer membrane (_e_) is +thick and double-contoured, separated by a clear interval from the very +thin but firm inner membrane (_i_). The large astropyle, or the +main-opening on the oral pole of the main axis, is closed by a large, +convex, radiate operculum (_o_), from which arises a short tubular +proboscis. On both sides of the opposite aboral pole (to the right and +left) are two conical parapylae or secondary openings (_u, u_). The space +between the inner membrane of the capsule and {1573}the nucleus is filled +up by protoplasm, containing numerous spherical vacuoles of equal size +(_v_); each vacuole encloses a small, dark, fat-granule. The large nucleus +(_n_) is either spherical or lenticular, and more or less depressed in the +main axis; its diameter is usually about half as great as that of the +enclosing capsule, 0.05 to 0.15, rarely less or more; it contains, enclosed +in a clear mass, numerous dark, roundish or oblongish nucleoli (_l_). + +Numerous preparations of Aulacanthida exhibited a central capsule with two +nuclei (Pl. 101, fig. 6), or a calymma with two central capsules (Pl. 104, +figs. 1, 3); so that the process of propagation by self-division, observed +already in many different PHAEODARIA, seems to happen very frequently in +the Aulacanthida. The voluminous phaeodium is usually about twice or three +times as large as the central capsule, and covers its oral or anterior +half; the colour of the roundish phaeodella composing it is sometimes more +green or brown, at other times more blackish. The roundish alveoles, which +fill up the rather firm jelly of the calymma, exhibit nearly the same shape +as in the common _Thalassicolla nucleata_. The surface of the calymma is +usually protected by the dense veil of tangential needles, and often forms +conical or tent-shaped elevations around the bases of the piercing radial +tubes (Pl. 102, fig. 1). + +_Synopsis of the Genera of Aulacanthida._ + + { Surface of the calymma + { naked, without tangential + { needles, 665. _Aulactinium_. + Radial tubes simple, { + without lateral and { Surface of the calymma + terminal branches. { covered by a veil of + { tangential needles, 666. _Aulacantha_. + + Radial tubes without { Terminal branches simple, 667. _Aulographis_. + lateral branches, but { + with a verticil of { Terminal branches forked + terminal branches. { or again ramified, 668. _Auloceros_. + + { Lateral branches + Radial tubes with { verticillate, 669. _Aulospathis_. + lateral and with { + terminal branches. { Lateral branches + { irregularly scattered, + { not verticillate, 670. _Aulodendron_. + + + +Subfamily 1. AULACTINIDA, Haeckel. + +_Definition._--#Aulacanthida# without external veil of tangential needles +on the surface of the calymma. + + + +Genus 665. _Aulactinium_,[283] n. gen. + +_Definition._--#Aulacanthida# without a veil of tangential needles, with +simple radial tubes, which bear neither lateral nor terminal branches. + +{1574}The genus _Aulactinium_ differs from all the other Aulacanthida in +the complete absence of the characteristic fine tangential needles, which +constitute in the latter an arachnoidal veil or mantle around the spherical +calymma. We accordingly divide the whole family into two subfamilies, the +Aulactinida with a naked calymma, and the Aulographida with a veil of +tangential needles. The radial tubes possess in the few species of +_Aulactinium_ observed a very simple shape, as in the closely allied +_Aulacantha_. + + +1. _Aulactinium actinastrum_, n. sp. (Pl. 101, figs. 6, 7). + +Radial tubes slenderly spindle-shaped, slightly curved, gradually tapering +from the middle towards both ends. The proximal two-thirds of the tubes +enclosed in the calymma are smooth; the distal freely prominent third is +armed with six to eight equidistant verticils of small conical teeth (ten +to fifteen in each verticil). + +_Dimensions._--Length of the tubes 0.5 to 1.5, breadth 0.02. + +_Habitat._--South Pacific, Station 289, depth 2550 fathoms. + + +2. _Aulactinium actinelium_, n. sp. (Pl. 101, fig. 8). + +Radial tubes cylindrical, straight, slightly tapering towards both ends. +Proximal two-thirds smooth, the distal third studded with numerous small +recurved thorns. + +_Dimensions._--Length of the tubes 0.6 to 0.9, breadth 0.02. + +_Habitat._--South Pacific, Station 293, depth 2025 fathoms. + + +3. _Aulactinium actinosphaerium_, n. sp. + +Radial tubes cylindrical, straight, smooth, of nearly equal breadth +throughout their whole length, without thorns and spathillae, pointed at +both ends. + +_Dimensions._--Length of the tubes 1.6 to 2.2, breadth 0.02 to 0.03. + +_Habitat._--Antarctic Sea, Station 157, depth 1950 fathoms. + + + +Subfamily 2. AULOGRAPHIDA, Haeckel. + +_Definition._--#Aulacanthida# with an external veil of interwoven, very +numerous and thin, hollow, tangential needles, entirely covering the +surface of the calymma. + + + +Genus 666. _Aulacantha_,[284] Haeckel, 1860, Monatsber. d. k. preuss. Akad. +d. Wiss. Berlin, p. 799. + +_Definition._--#Aulacanthida# with a veil of tangential needles, and with +simple radial tubes, which bear neither lateral nor terminal branches. + +{1575}The genus _Aulacantha_, hitherto the only representative of this +family, was founded by me in 1860 for the cosmopolitan _Aulacantha +scolymantha_, the most common and most widely distributed of all the +members of the family. It is the simplest form of the Aulographida, or of +those Aulacanthida in which the spherical surface of the calymma is densely +covered with interwoven tangential needles. The large radial tubes of +_Aulacantha_ possess a very simple shape, as in the preceding +_Aulactinium_, and have neither lateral nor terminal branches. + + +1. _Aulacantha scolymantha_, Haeckel. + + _Aulacantha scolymantha_, Haeckel, 1862, Monogr. d. Radiol., p. 263, Taf. + ii. figs. 1, 2, Taf. iv. figs. 1-5. + + _Aulacantha scolymantha_, R. Hertwig, 1879, Organism. d. Radiol., p. 88, + Taf. ix. fig. 3, Taf. x. figs. 7-10. + +Radial tubes cylindrical, straight, of nearly equal breadth throughout +their whole length, somewhat inflated on the proximal basal end, smooth +throughout the greater part of their length, but in the distal third +dentate, with numerous (ten to forty) small pointed teeth, which are curved +outwards, and shorter than the thickness of the tube. + +_Dimensions._--Length of the tubes 0.5 to 2.0, breadth 0.01 to 0.02. + +_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Indian, Pacific; at many +Stations; surface and at various depths; the most common of all +Aulacanthida. + + +2. _Aulacantha tubulosa_, n. sp. + +Radial tubes cylindrical or nearly spindle-shaped, straight, gradually +tapering towards the two pointed ends, twice as broad in the middle third +as in the outer and inner third, smooth in the inner half, dentate in the +outer half, with very numerous (one hundred to two hundred) short conical +teeth, which are scarcely one-fourth as large as the greatest breadth of +the tube. + +_Dimensions._--Length of the tubes 0.4 to 0.5, breadth in the middle part +0.02 to 0.03. + +_Habitat._--Central Pacific, Stations 271 to 274, surface. + + +3. _Aulacantha spinosa_, n. sp. (Pl. 105, fig. 4). + +Radial tubes cylindrical, straight, of equal breadth throughout their whole +length, rounded on the proximal base, smooth in the inner proximal half, +dentate or spinescent in the outer distal half, with numerous (fifty to +eighty) slender conical teeth, which are curved forwards, increasing in +size towards the distal end, and somewhat longer than the breadth of the +tube. + +_Dimensions._--Length of the tubes 0.8 to 1.2, breadth 0.015 to 0.02. + +_Habitat._--North Pacific, Stations 241 to 253, surface. + + +{1576}4. _Aulacantha cannulata_, n. sp. (Pl. 105, fig. 16). + +Radial tubes cylindrical in the inner proximal half, prismatic in the outer +distal half, with from three to six, usually four, prominent, thick, +parallel edges, which are dentate towards the thicker distal end; their +teeth short, conical, directed outwards, scarcely one-fourth as long as the +thickness of the tube. The edges are separated in the distal third by more +or less deep furrows, like a channelled column. + +_Dimensions._--Length of the tubes 1.2 to 2.5, breadth 0.03 to 0.04. + +_Habitat._--South Pacific, Stations 291 to 293, surface. + + +5. _Aulacantha clavata_, n. sp. + +Radial tubes more or less irregularly curved, in the inner proximal half +slenderly conical, and gradually tapering towards the inflated base, in the +outer distal half club-shaped, armed with a few (five to twenty) short +conical teeth. + +_Dimensions._--Length of the tubes 1.0 to 1.2, breadth in the middle pact +0.01, in the distal part 0.04. + +_Habitat._--South Atlantic, Station 318, depth 2040 fathoms. + + +6. _Aulacantha laevissima_, n. sp. + +Radial tubes cylindrical, straight, of nearly equal breadth throughout +their whole length; the inner proximal end rounded, the outer distal end +pointed. Surface of the tubes perfectly smooth, without any teeth. The +thickness and length of the simple spicula, as well as the thickness of +their wall, are very variable in this species. + +_Dimensions._--Length of the tubes 0.5 to 4.2, breadth 0.003 to 0.02. + +_Habitat._--North Atlantic, Station 253, Faeroee Channel, surface, John +Murray. + + + +Genus 667. _Aulographis_,[285] Haeckel, 1879, Sitzungsb. med.-nat. +Gesellsch. Jena, Dec. 12, p. 5. + +_Definition._--#Aulacanthida# with a veil of tangential needles, and with +radial tubes, which bear no lateral branches, but at the distal end a +verticil of simple terminal branches. + +The genus _Aulographis_, the richest in the number of species among all +Aulacanthida, differs from the preceding _Aulacantha_, its ancestral form, +in the development of simple terminal branches, which form either a fork or +a verticil. The branches are either smooth or spiny, but not ramified as in +the following genus, _Auloceros_. Their distal {1577}ends are either simply +pointed or bear a terminal spathilla, or a little crown of recurved teeth. +According to these differences we may dispose the twenty-six species +described into four subgenera. + + + +Subgenus 1. _Aulographantha_, Haeckel. + +_Definition._--Terminal branches of the radial tubes simple, smooth, +without lateral teeth and terminal spathillae. Tubes usually thin and +fragile. + + +1. _Aulographis pandora_, n. sp. (Pl. 103, figs. 2-9). + +Radial tubes cylindrical, slender, straight or slightly curved, of equal +breadth. Terminal branches of the tubes very variable in size and number +(two to six, usually three or four), without lateral teeth and terminal +spathillae, slender, conical, slightly curved, directed outwards, twice to +four times (rarely five to eight times) as long as the breadth of the +tubes. This species is extraordinarily variable in the number and size of +the simple terminal branches; the eight tubes, shown in figs. 2 to 9, are +all found in one and the same specimen. + +_Dimensions._--Length of the tubes 0.5 to 1.5, breadth 0.01 to 0.03; +branches 0.02 to 0.12. + +_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Indian, Pacific; surface +and in various depths. + + +2. _Aulographis bovicornis_, n. sp. (Pl. 103, figs. 12-14). + +Radial tubes cylindrical, slender, straight, of equal breadth. Terminal +branches usually two (rarely three), smooth, without lateral teeth and +terminal spathillae, eight to ten times as long as the breadth of the tube, +pointed, S-shaped, or curved like the horns of an ox. + +_Dimensions._--Length of the tubes 0.6 to 0.8, breadth 0.015 to 0.02; +branches 0.1 to 0.2. + +_Habitat._--South Atlantic (east of Buenos Ayres), Stations 323 to 325, +surface. + + +3. _Aulographis taumorpha_, n. sp. (Pl. 103, fig. 16). + +Radial tubes cylindrical, slender, straight, gradually tapering towards the +pointed proximal end. Terminal branches constantly two, opposite in a +tangential, slightly concave or nearly straight line, ten to twelve times +as long as the breadth of the tube, smooth, straight in the proximal part, +recurved in the distal part. + +_Dimensions._--Length of the tubes 0.7 to 0.8, breadth 0.01 to 0.015; +branches 0.1 to 0.15. + +_Habitat._--North Pacific, Station 231, depth 2250 fathoms. + + +{1578}4. _Aulographis triglochin_, n. sp. (Pl. 103, fig. 17). + +Radial tubes robust, club-shaped at the distal end. Terminal branches three +(rarely two or four), widely divergent, geniculated and recurved, smooth, +without lateral teeth and terminal spathillae. + +_Dimensions._--Length of the tubes 1.2 to 1.8, breadth 0.02; branches 0.12 +to 0.15. + +_Habitat._--Central Pacific, Stations 271 to 274, surface. + + +5. _Aulographis cruciata_, n. sp. (Pl. 103, fig. 25). + +Radial tubes slender, cylindrical, of equal breadth. Terminal branches +almost constantly four, equal, regularly crossed (very rarely three or +five), slender, straight or slightly curved, smooth, divergent outwards, +six to eight times as long as the breadth of the tube. + +_Dimensions._--Length of the tubes 1.0 to 1.5, breadth 0.02; branches 0.12 +to 0.15. + +_Habitat._--South Atlantic, Stations 325 to 332, surface. + + +6. _Aulographis ancorata_, n. sp. (Pl. 103, fig. 21). + +Radial tubes slender, cylindrical, straight. Terminal branches constantly +four, equal, regularly crossed, arcuato-recurved or nearly semicircular, +smooth, six to eight times as long as the breadth of the tube. Resembling +an anchor with four teeth. + +_Dimensions._--Length of the tubes 0.5 to 0.7, breadth 0.012 to 0.015; +branches 0.07 to 0.09. + +_Habitat._--South-west Atlantic, Station 318, depth 2040 fathoms. + + +7. _Aulographis stellata_, n. sp. (Pl. 103, figs. 23, _a_-_c_). + +Radial tubes club-shaped, gradually thickened towards the distal end. +Terminal branches stellate, numerous (five to ten or more), diverging in +all directions, smooth, straight or slightly curved, slenderly conical, +three to five times as long as the distal breadth of the tube. The branches +are very variable in size, sometimes very small (figs. _a_, _b_). + +_Dimensions._--Length of the tubes 0.4 to 0.8, breadth 0.02; branches 0.01 +to 0.02. + +_Habitat._--Indian Ocean, Madagascar (Rabbe), surface. + + +8. _Aulographis penicillata_, n. sp. + +Radial tubes slender, cylindrical, of equal breadth. Terminal branches +pencil-shaped, smooth, very numerous (twenty to thirty or more), diverging +outwards, curved, eight to ten times as long as the breadth of the tube, +very thin and fragile, resembling a brush. + +_Dimensions._--Length of the tubes 1.0 to 1.5, breadth 0.02; branches 0.15 +to 0.2. + +_Habitat._--North Atlantic (Antilles), Weber, surface. + + +{1579}9. _Aulographis pistillum_, n. sp. (Pl. 105, fig. 6). + +Radial tubes club-shaped, robust, straight, gradually thickened towards the +distal end. Terminal branches eight to ten (usually nine), conical, smooth, +slightly curved, divergent outwards like a regular corona. + +_Dimensions._--Length of the tubes 0.5 to 0.6, distal breadth 0.04; +branches 0.08. + +_Habitat._--North Atlantic, Station 354, depth 1675 fathoms. + + + +Subgenus 2. _Aulographella_, Haeckel. + +_Definition._--Terminal branches of the radial tubes without terminal +spathillae, but with lateral teeth or secondary spines. (Tubes usually very +stout and robust, club-shaped.) + + +10. _Aulographis triaena_, n. sp. (Pl. 105, fig. 8). + +Radial tubes club-shaped, straight, tapering gradually towards the rounded +proximal end. Terminal branches constantly three, divergent, very stout, +eight to ten times as long as the breadth of the tube, each studded with +three to six irregular, conical, secondary spines. Sometimes the branches +become forked, the species passing over into _Auloceros cervinus_. + +_Dimensions._--Length of the tubes 1.2 to 1.5, breadth 0.004 to 0.06; +branches 0.3 to 0.5. + +_Habitat._--South Pacific, Station 299, depth 2160 fathoms. + + +11. _Aulographis martagon_, n. sp. (Pl. 105, fig. 7). + +Radial tubes club-shaped or slenderly conical, strongly thickened towards +the distal end. Terminal branches six to nine, conical, slightly curved, +divergent outwards, studded outside with small, conical, secondary spines, +twice to three times as long as the breadth of the tube. + +_Dimensions._--Length of the tubes 1.0 to 1.2, breadth 0.04 to 0.05; +branches 0.1 to 0.15. + +_Habitat._--South Atlantic, Station 318, depth 2040 fathoms. + + +12. _Aulographis flammabunda_, n. sp. (Pl. 105, fig. 9). + +Radial tubes club-shaped, more or less curved, with thickened distal ends. +Terminal branches three to six, conical, very stout, three to four times as +long as the breadth of the tube, densely studded with numerous, crowded, +conical, secondary spines, which are very irregular and more or less +curved, resembling the flames of a fire. + +_Dimensions._--Length of the tubes 1.0 to 1.2, distal breadth 0.08 to 0.1; +branches 0.2 to 0.4. + +_Habitat._--South Pacific, Station 302, depth 1450 fathoms. + + +{1580}13. _Aulographis gemmascens_, n. sp. (Pl. 105, fig. 11). + +Radial tubes club-shaped, more or less curved, with thickened distal end. +Terminal branches three to nine (usually three larger and six smaller) +stout, conical, studded with irregular, straight, conical, secondary +spines, crowded and densely aggregated, like the leaves in a bud. + +_Dimensions._--Length of the spines 1.5 to 1.8, distal breadth 0.07 to 0.1; +branches 0.2 to 0.6. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + +14. _Aulographis flosculus_, n. sp. (Pl. 105, fig. 10). + +Radial tubes club-shaped, straight, tapering gradually towards the rounded +proximal end. Terminal branches nine to twelve, stout, conical, twice to +three times as long as the breadth of the tube, studded with irregular +secondary spines, connected in the proximal half by a solid, cap-shaped, +flinty lamella, so that the terminal corona resembles a flower. The hollow +canal of the tube sends a thin branch into each branch of the crown. + +_Dimensions._--Length of the tubes 1.2 to 1.8, distal breadth 0.04 to 0.05; +branches 0.1 to 0.2. + +_Habitat._--North Atlantic, Faeroee Channel (Gulf Stream), John Murray, +depth 600 fathoms. + + + +Subgenus 3. _Aulographidium_, Haeckel. + +_Definition._--Terminal branches of the radial tubes armed with terminal +spathillae (or whorls of small radial teeth), but without lateral denticles +or spines. + + +15. _Aulographis furcula_, n. sp. (Pl. 103, figs. 10, 11). + +Radial tubes cylindrical, slender, slightly curved. Terminal branches +usually two, sometimes on single tubes three, eight to ten times as long as +the tube is broad, strongly curved, ascending vertically from a horizontal +base, with a terminal spathilla of four crossed teeth at the distal end. + +_Dimensions._--Length of the tubes 0.6 to 0.8, breadth 0.006 to 0.008; +branches 0.06 to 0.08. + +_Habitat._--North-west Pacific (off Japan), Station 231, depth 2250 +fathoms. + + +16. _Aulographis triangulum_, n. sp. (Pl. 103, fig. 15). + +Radial tubes cylindrical, slender, straight. Terminal branches constantly +three, slender, slightly curved, nearly horizontally (tangentially) +expanded, eight to ten times as long as the tube is broad, with a terminal +spathilla of four recurved teeth which are opposite in pairs. Since the +angles between the three branches are equal (= 120d) they correspond to the +axes of an equilateral triangle. + +_Dimensions._--Length of the tubes 1.2, breadth 0.015 to 0.02; branches 0.1 +to 0.12. + +_Habitat._--South Pacific, Station 289, depth 2550 fathoms. + + +{1581}17. _Aulographis tetrancistra_, n. sp. (Pl. 103, fig. 22). + +Radial tubes slender, cylindrical, straight. Terminal branches four to six +(usually four), eight to ten times as long as the tube is broad, slightly +curved and widely divergent, with a terminal spathilla of four crossed +recurved teeth. + +_Dimensions._--Length of the tubes 0.5 to 0.7, breadth 0.01; branches 0.08 +to 0.1. + +_Habitat._--South Pacific, Station 285, depth 2375 fathoms. + + +18. _Aulographis hexancistra_, n. sp. (Pl. 103, figs. 18, 19). + +Radial tubes club-shaped, slightly curved, gradually thickened from the +proximal to the distal end. Terminal branches four to eight (usually six in +the majority of tubes), widely divergent, nearly straight, three to four +times as long as the tube is broad, with a terminal spathilla of six +(rarely five) recurved teeth. + +_Dimensions._--Length of the tubes 0.4 to 0.6, breadth 0.01 to 0.02; +branches 0.04 to 0.08. + +_Habitat._--North Pacific, Stations 244 to 253, depth 2050 to 3125 fathoms. + + +19. _Aulographis polyancistra_, n. sp. + +Radial tubes club-shaped, straight, thickened towards the distal end. +Terminal branches ten to twenty, smooth, strongly curved, disposed in a +corona, six to eight times as long as the tube is broad, each with a +terminal spathilla of eight to twelve radial teeth. + +_Dimensions._--Length of the tubes 0.6 to 0.8, distal breadth 0.02; +branches 0.12 to 0.16. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + +20. _Aulographis asteriscus_, n. sp. (Pl. 103, fig. 24). + +Radial tubes slender, cylindrical, straight, equally broad. Terminal +branches six to nine, widely divergent, disposed in a radiate corona, +around a central branch, which is the distal prolongation of the tube +itself. Each branch bears a stellate terminal spathilla, composed of ten to +twenty conical teeth, which radiate in all directions. + +_Dimensions._--Length of the tubes 0.5 to 0.8, breadth 0.02; branches 0.06 +to 0.09. + +_Habitat._--South Atlantic, Station 318, depth 2040 fathoms. + + + +Subgenus 4. _Aulographonium_, Haeckel. + +_Definition._--Terminal branches of the radial tubes armed with numerous +lateral denticles, and with terminal spathillae (or whorls of small radial +teeth). + + +{1582}21. _Aulographis dentata_, n. sp. (Pl. 103, fig. 20). + +Radial tubes slender, cylindrical, equally broad, scarcely inflated at the +distal end. Terminal branches six to eight, curved, disposed in a corona +around a straight central branch, eight to ten times as long as the tube is +broad, armed with numerous stout recurved lateral denticles and with a +terminal spathilla of five or six recurved teeth. + +_Dimensions._--Length of the tubes 1.5 to 2.5, breadth 0.03; branches 0.15 +to 0.2 long. + +_Habitat._--North Atlantic, Station 354, depth 1675 fathoms. + + +22. _Aulographis pulvinata_, n. sp. (Pl. 103, fig. 26). + +Radial tubes club-shaped, straight, gradually thickened towards the distal +end, which bears a broad, circular, biconvex cushion. The margin of this +cushion bears two alternating verticils of radially divergent, straight, +terminal branches, which are twice to three times as long as the tube is +broad. Each branch is armed with two opposite lateral rows of numerous +small denticles, and bears a terminal spathilla with six to eight recurved +radial teeth. + +_Dimensions._--Length of the tubes 2.0 to 2.4, distal breadth 0.03 to 0.07; +branches 0.05 to 0.08 long. + +_Habitat._--South-east Pacific (off Valparaiso), Station 298, depth 2225 +fathoms. + + +23. _Aulographis tripentas_, n. sp. (Pl. 105, fig. 13, 13_a_). + +Radial tubes club-shaped, straight, thickened towards the inflated distal +end, which bears three alternating verticils of terminal branches, each +with five radial branches. The ten branches of the inner and outer +verticils are perradial, smooth; the alternating five branches of the +middle verticil are armed with recurved lateral denticles. Each of the +fifteen branches bears a terminal spathilla with five to seven recurved +teeth. + +_Dimensions._--Length of the spines 2.0 to 2.5, distal breadth 0.03 to +0.06; branches 0.1 long. + +_Habitat._--South-east Pacific (off Juan Fernandez), Station 299, depth +2160 fathoms. + + +24. _Aulographis verticillata_, n. sp. (Pl. 105, fig. 12, 12_a_). + +Radial tubes cylindrical, equally broad, with an inflated ellipsoidal knob +at the distal end. This knob bears twenty to thirty slender, slightly +curved, terminal branches, which are regularly arranged in five radial or +meridional rows, and in four to six concentric verticils. The branches are +five to ten times as long as the tube is broad, and armed with two opposite +rows of lateral denticles, and with a terminal spathilla of six to eight +recurved teeth. + +_Dimensions._--Length of the tubes 1.5 to 1.8, breadth 0.01 to 0.02; +branches 0.5 to 1.0 long. + +_Habitat._--South Pacific, Station 293, depth 2025 fathoms. + + +25. _Aulographis serrulata_, n. sp. (Pl. 103, fig. 27). + +Radial tubes club-shaped, curved, thickened towards the inflated +ellipsoidal distal end, which bears a bunch of fifteen to twenty-five +terminal branches, arranged more or less regularly in radial {1583}or +meridional rows and concentric horizontal verticils. The branches are +irregularly curved, twice to four times as long as the distal end of the +tube, armed with two opposite rows of lateral denticles, and at the distal +end with a spathilla of six radial teeth. + +_Dimensions._--Length of the tubes 1.5 to 1.8, breadth 0.02 to 0.04; +branches 0.1 to 0.15 long. + +_Habitat._--North Pacific, Stations 253 and 254, depth 3025 to 3125 +fathoms. + + +26. _Aulographis candelabrum_, n. sp. (Pl. 103, fig. 1). + +Radial tubes club-shaped, straight, thickened towards the distal end and +constricted beyond the ovate, inflated, terminal knob. This knob is similar +to a candelabrum and bears a corona of six to nine strongly curved terminal +branches, which are eight to ten times as long as the tube is broad, armed +with scattered lateral denticles, and with a spathilla of five to seven +radial teeth. + +_Dimensions._--Length of the tubes 1.6 to 2.4, breadth 0.03 to 0.05; +branches 0.2 to 0.3 long. + +_Habitat._--South-east Pacific (off Juan Fernandez), Station 300, depth +1375 fathoms. + + + +Genus 668. _Auloceros_,[286] n. gen. + +_Definition._--#Aulacanthida# with a veil of tangential needles, and with +radial tubes, which bear no lateral branches, but at the distal end a +verticil of ramified or forked terminal branches. + +The genus _Auloceros_ differs from the preceding closely allied +_Aulographis_, its ancestral form, in the ramification of the verticillate +terminal branches. They are either simply forked or again ramified, and +their distal ends are either simply pointed or armed with a terminal +spathilla, or a little crown of recurved teeth. Some forms of this genus +belong to the most elegant and graceful PHAEODARIA, as the _Auloceros +elegans_ figured, which I observed living in the Indian Ocean. + + + +Subgenus 1. _Auloceraea_, Haeckel. + +_Definition._--Distal ends of the terminal branches pointed, smooth, +without spathilla (or corona of radiate denticles). + + +1. _Auloceros furcosus_, n. sp. (Pl. 102, figs. 2-6). + +Radial tubes slender, spindle-shaped or nearly cylindrical, more or less +tapering towards the two ends. Terminal branches slender, curved, twice to +four times as long as the tube is broad, very variable in number (usually +two or three, rarely four, five, or six; compare figs. 2-6), once or twice +forked; the secondary branches are short, irregular, and pointed. No +terminal spathillae. {1584}In some specimens of this species all the tubes +bear two or three terminal branches, whilst in others there are tubes with +four, five, or six branches intermingled. When the number of the terminal +branches is constant in single localities, this transformistic or +"Darwinian" species may be divided into the following "subspecies:" (1) +_Auloceros pandora_ (with variable numbers); (2) _Auloceros bifurca_ (fig. +2); (3) _Auloceros trifurca_ (fig. 3); (4) _Auloceros quadrifurca_ (fig. +4); (5) _Auloceros quinquefurca_ (fig. 5); (6) _Auloceros sexfurca_ (fig. +6). + +_Dimensions._--Length of the tubes 1.5 to 2.5, breadth 0.02 to 0.03; +branches 0.05 to 0.15 long. + +_Habitat._--North Pacific, Stations 231 to 253, surface and at various +depths. + + +2. _Auloceros trigeminus_, n. sp. (Pl. 102, fig. 7). + +Radial tubes club-shaped, gradually thickened towards the inflated distal +end. Terminal branches short, scarcely longer than the tube is broad, two +constantly opposite, each with three equal, conical, short secondary +branches. No terminal spathillae. + +_Dimensions._--Length of the tubes 0.6 to 0.8, breadth 0.02 to 0.03; +branches 0.04 to 0.08. + +_Habitat._--North Atlantic, Station 353, depth 2965 fathoms. + + +3. _Auloceros capreolus_, n. sp. (Pl. 102, fig. 8). + +Radial tubes cylindrical, equally broad. Terminal branches in two opposite +clustered bunches, each with sixteen to eighteen unequal secondary +branches. The total length and breadth of each cluster is about four times +as great as the tube is broad. No terminal spathillae. + +_Dimensions._--Length of the tube 1.5 to 2.0, breadth 0.03; branches 0.07 +to 0.1. + +_Habitat._--South Pacific, Station 295, depth 1500 fathoms. + + +4. _Auloceros cervinus_, n. sp. (Pl. 102, figs. 9, 10). + +Radial tubes slender, spindle-shaped, slightly curved, tapering gradually +from the middle towards the two ends. Terminal branches constantly three, +obliquely ascending, each twice or three times forked (often more or less +irregularly), with slender, curved, secondary and tertiary branches (twenty +to twenty-four on each tube); the latter are scarcely half as broad as the +three main branches of each tube. No terminal spathillae. + +_Dimensions._--Length of the tubes 2.0 to 3.5, breadth 0.03 to 0.04; +branches 0.12 to 0.15 long. + +_Habitat._--South Atlantic, Station 325, depth 2650 fathoms. + + +5. _Auloceros elegans_, n. sp. (Pl. 102, fig. 1). + +Radial tubes slender, cylindrical, straight, equally broad. Terminal +branches two or three, more or less irregularly branched, each with twelve +to eighteen curved and pointed secondary branches. No terminal spathillae. +Differs from the preceding _Auloceros cervinus_ in the cylindrical form of +the thinner straight tubes, and the more irregular ramification; the +branches are nearly {1585}tangentially expanded, The specimen figured, with +expanded pseudopodia, red central capsule, and green phaeodium, was +observed living by me in 1882 in Ceylon. + +_Dimensions._--length of the tubes 1.0 to 2.0, breadth 0.02 to 0.03; +branches 0.15 to 0.3. + +_Habitat._--Indian Ocean, Ceylon (south of Matura), Haeckel, surface. + + + +Subgenus 2. _Auloceratium_, Haeckel. + +_Definition._--Distal ends of the terminal branches with a spathilla, or a +small corona of radial, usually recurved teeth. + + +6. _Auloceros dicranaster_, n. sp. (Pl. 105, figs. 14, 15). + +Radial tubes cylindrical, straight, equally broad. Terminal branches +tangential, forked, expanded horizontally, five to six times as long as the +tube is broad; their number is usually five (more rarely four or six), and +each is divided into two short, equal, divergent, secondary branches, armed +at the distal end with a spathilla of five or six unequal recurved teeth. + +_Dimensions._--Length of the tubes 1.0 to 1.5, breadth 0.01 to 0.02; +branches 0.05 to 0.08. + +_Habitat._--North Pacific, Stations 244 to 252, depth 2050 to 3050 fathoms. + + +7. _Auloceros spathillaster_, n. sp. (Pl. 102, fig. 12). + +Radial tubes club-shaped or nearly cylindrical, straight, often thickened +towards the distal end. Terminal branches ascending, three to six, usually +four, partly simple, partly forked, slightly curved. The branches are from +twice to three times as long as the tube is broad, and much thinner; at the +distal end they are armed with a spathilla of five or six recurved teeth. + +_Dimensions._--Length of the tubes 2.0 to 2.5, breadth 0.02 to 0.03; +branches 0.08 to 0.12. + +_Habitat._--South Atlantic, Station 319, depth 2425 fathoms. + + +8. _Auloceros arborescens_, n. sp, (Pl. 102, figs. 11, 13). + +Radial tubes club-shaped, irregularly curved, thickened towards the distal +end. Terminal branches two opposite (rarely three or four), forked near the +base, and either dichotomously or more irregularly branched; each tube +bears fifteen to thirty, usually twenty to twenty-four, secondary branches, +which are irregularly curved, and armed at the distal end with a spathilla +of four to eight recurved teeth. The tubes are more richly branched than in +the preceding, smaller, closely allied species, and the branches are more +flatly expanded. + +_Dimensions._--Length of the tubes 2.6 to 3.3, breadth 0.03 to 0.04; +branches 0.1 to 0.2. + +_Habitat._--South Pacific, Stations 288 to 295, depth 1500 to 3000 fathoms. + + + +{1586}Genus 669. _Aulospathis_,[287] n. gen. + +_Definition._--#Aulacanthida# with a veil of tangential needles, and with +radial tubes, which bear two verticils of branches, a distal verticil of +terminal branches, and a proximal verticil of lateral branches. + +The genus _Aulospathis_ and the following _Aulodendron_ differ from the +preceding Aulacanthida in the possession of lateral branches; these are +usually similar to the terminal branches, and irregularly scattered along +the distal half of the tubes in _Aulodendron_. In _Aulospathis_, however, +the largest form in the family, each tube bears two whorls or verticils +only, a verticil of terminal branches at the distal end, and a verticil of +lateral branches beyond the latter, between the middle and distal third of +the tube. The number of branches in each verticil is usually from two to +four, rarely more; it is, however, very variable, so that the ten species +described in the sequel are "Darwinian species," derived either from +_Aulospathis polymorpha_, or from _Aulospathis variabilis_. Each branch +bears at the distal end a spathilla, the teeth of which are very variable +in form, number and arrangement. + + + +Subgenus 1. _Aulospathessa_, Haeckel. + +_Definition._--Distal ends of the radial tubes inflated, usually in the +form of an ovate or pyriform terminal knob. + + +1. _Aulospathis bifurca_, n. sp. (Pl. 104, figs. 1-5). + +Radial tubes with an inflated ovate terminal knob at the distal end, which +bears two divergent, curved, terminal branches (often a few tubes bear +three or four branches instead of the usual two). Proximal whorl usually +cruciate, with four irregularly crossed lateral branches (but often with +five or six, more rarely with two or three). + +_Dimensions._--Length of the tubes 0.15 to 25 mm., breadth 0.04 to 0.06; +branches 0.1 to 0.15. + +_Habitat._--South Pacific, Stations 293 to 295, depth 1500 to 2270 fathoms. + + +2. _Aulospathis trifurca_, n. sp. (Pl. 104, figs. 6, 7, 7_a_). + +Radial tubes with an inflated ovate terminal knob at the distal end, which +bears three divergent, straight, or slightly curved terminal branches +(often a few tubes bear two or four branches instead of the usual three). +Proximal whorl irregular, usually with six divergent, straight, lateral +branches. + +_Dimensions._--Length of the tubes 2.2 to 3.4, breadth 0.03 to 0.05; +branches 0.1 to 0.15. + +_Habitat._--South Pacific (off Valparaiso), Stations 298 to 300, depth 1375 +to 2225 fathoms. + + +{1587}3. _Aulospathis quadrifurca_, n. sp. + +Radial tubes with an inflated ovate terminal knob at the distal end, which +bears four crossed, divergent, curved terminal branches. Proximal whorl +also rather regular, with a cross of four straight lateral branches. + +_Dimensions._--Length of the tubes 3.0 to 4.0, breadth 0.04 to 0.08; +branches 0.2 to 0.3. + +_Habitat._--South Pacific, Station 291, depth 2250 fathoms. + + +4. _Aulospathis polymorpha_, n. sp. (Pl. 104, figs. 10-13). + +Radial tubes with an inflated ovate terminal knob at the distal end, which +bears a variable number of divergent, curved, irregular, terminal branches. +Usually the majority of the tubes bear three branches, whilst others +exhibit two or four, sometimes also five or six. Proximal whorl also very +variable and irregular, with two to six, usually three or four unequal +branches. + +_Dimensions._--Length of the tubes 2.0 to 4.0, breadth 0.04 to 0.06; +branches 0.1 to 0.3. + +_Habitat._--South Pacific, Station 289, depth 2550 fathoms. + + + +Subgenus 2. _Aulospathilla_, Haeckel. + +_Definition._--Distal ends of the radial tubes of equal breadth or tapering +gradually, not inflated, without terminal knobs. + + +5. _Aulospathis diodon_, n. sp. + +Radial tubes without inflated terminal knob, forked at the tapering distal +end, with two divergent curved branches of equal size. Proximal whorl +cruciate, with four rather equal, crossed, straight, lateral branches +(sometimes three or five instead of four in single tubes). + +_Dimensions._--Length of the tubes 2.0 to 2.5, breadth 0.03 to 0.04; +branches 0.1 to 0.3. + +_Habitat._--North Pacific, Station 231, depth 2250 fathoms. + + +6. _Aulospathis triodon_, n. sp. (Pl. 104, fig. 8). + +Radial tubes without inflated terminal knob, with three divergent, slightly +curved, terminal branches. Proximal whorl with a variable number of curved +lateral branches, usually also three (often two or four, rarely more). + +_Dimensions._--Length of the tubes 2 to 3, breadth 0.03 to 0.05; branches +0.2 to 0.3. + +_Habitat._--North Pacific, Stations 250 to 253, depth 2740 to 3125 fathoms. + + +{1588}7. _Aulospathis tetrodon_, n. sp. (Pl. 104, fig. 9). + +Radial tubes without inflated terminal knob, with four crossed, divergent, +slightly curved terminal branches. Proximal whorl usually with an irregular +cross of four lateral branches (often five or six, rarely two or three +instead of the usual four). + +_Dimensions._--Length of the tubes 2.0 to 2.5, breadth 0.03 to 0.04; +branches 0.2 to 0.3. + +_Habitat._--North Pacific, Stations 244 to 245, depth 2775 to 2900 fathoms. + + +8. _Aulospathis hexodon_, n. sp. + +Radial tubes without inflated terminal knob, with three forked, curved +branches at the distal end, so that each tube usually bears six terminal +branches; but other tubes of the same specimen bear only three simple or a +few irregularly forked branches. Proximal whorl usually with six curved, +irregular, lateral branches. + +_Dimensions._--Length of the tubes 2.0 to 3.0, breadth 0.03 to 0.06; +branches 0.2 to 0.5. + +_Habitat._--Western Tropical Pacific, Station 224, depth 1850 fathoms. + + +9. _Aulospathis furcata_, n. sp. + +Radial tubes without inflated terminal knob, with a variable number of +unequal terminal branches, which are partly simple, partly irregularly +forked or branched; the usual number of terminal branches is three or four, +more rarely two or five or six. Proximal whorl very irregular, usually with +four to six unequal, lateral branches. + +_Dimensions._--Length of the tubes 2.0 to 2.5, breadth 0.03 to 0.05; +branches 0.1 to 0.3. + +_Habitat._--Stations 265 to 268, depth 2700 to 2900 fathoms. + + +10. _Aulospathis variabilis_, n. sp. (Pl. 104, figs. 14-17). + +Radial tubes without inflated terminal knob, with a variable number of +unequal terminal branches, which are constantly simple, never forked; the +usual number is in the majority of the tubes three or four, often also two, +rarely five to eight. Proximal whorl irregular, with a variable number of +lateral branches (usually four to six). + +_Dimensions._--Length of the tubes 2.0 to 3.0, breadth 0.03 to 0.06; +branches 0.1 to 0.3. + +_Habitat._--Central Pacific, Stations 271 to 274, depth 2350 to 2750 +fathoms. + + + +Genus 670. _Aulodendron_,[288] n. gen. + +_Definition._--#Aulacanthida# with a veil of tangential needles, and with +radial tubes, which bear numerous, irregularly scattered, lateral and +terminal branches. + +{1589}The genus _Aulodendron_ differs from the other Aulacanthida in the +possession of lateral and terminal branches, which are irregularly +scattered on the radial tubes and not arranged in regular verticils. The +branches are usually short, simple or forked, rarely longer and again +irregularly ramified. + + +1. _Aulodendron antarcticum_, n. sp. (Pl. 105, fig. 5). + +Radial tubes cylindrical, more or less curved, in the inner proximal half +smooth and half as broad as in the outer distal half, which is studded with +irregularly curved, partly branched spines, arising usually perpendicularly +from the tube. The majority of the spines usually simple, the minority +forked, with two to four short branches, the largest spines scarcely twice +as long as the breadth of the tube. + +_Dimensions._--Length of the tubes 0.7 to 0.9, breadth 0.01 to 0.02; length +of the branches 0.02 to 0.04. + +_Habitat._--Antarctic Ocean (Kerguelen), Stations 156 to 159, surface. + + +2. _Aulodendron pacificum_, n. sp. (Pl. 105, fig. 2). + +Radial tubes cylindrical, slightly curved, in the proximal half smooth, in +the distal half with scattered lateral branches, which are partly simple, +partly forked, about twice as long as the breadth of the tube, and bear at +the distal end a spathilla with five to six recurved teeth. The distal end +of the tubes bears a spherical knob, which is separated by a deep stricture +and armed with a bunch of six to twelve strong conical teeth. + +_Dimensions._--Length of the tubes 1 to 1.2, breadth 0.015 to 0.02; +branches 0.03 to 0.04. + +_Habitat._--South Pacific, Station 293, depth 2025 fathoms. + + +3. _Aulodendron australe_, n. sp. (Pl. 105, fig. 3). + +Radial tubes cylindrical, straight, thin, smooth in the proximal half, +armed with numerous lateral branches in the distal half; the majority of +the branches forked, about as long as the breadth of the tube, with two or +three short ramules, each of which bears a spinulate terminal knob. The +distal end of the tubes also forked, with two or three divergent branches. + +_Dimensions._--Length of the tubes 1.2 to 1.6, breadth 0.01 to 0.012. + +_Habitat._--South Pacific, Station 289; New Zealand, Station 169, surface. + + +4. _Aulodendron atlanticum_, n. sp. + +Radial tubes cylindrical, tapering gradually towards the two ends; smooth +and straight in the proximal half, irregularly curved and branched in the +distal half, with ten to twenty (rarely more) branches, which arise almost +perpendicularly from the tube. The proximal branches are from four to eight +times as long as the greatest breadth of the tube, forked, with two or +three short ramules; {1590}the distal branches are much smaller and simple. +The distal end of each branch bears a spathilla with four to six short +teeth. + +_Dimensions._--Length of the tubes 2.4 to 3.6, breadth 0.06 to 0.08. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +5. _Aulodendron indicum_, n. sp. (Pl. 105, fig. 1). + +Radial tubes cylindrical, irregularly curved, tapering gradually towards +the two ends; smooth in the proximal half, irregularly branched in the +distal half, with ten to twenty or more curved branches. The proximal +branches are very large, one-sixth to one-fourth as long as the tube and +irregularly ramified; the distal branches are much shorter, also ramified +or simple. All the branches are more or less curved and bear a spinulate +knob at the distal end. + +_Dimensions._--Length of the tubes 1.2 to 1.8, breadth 0.02 to 0.03; length +of the branches 0.1 to 0.3. + +_Habitat._--Indian Ocean; Cocos Islands (Rabbe), surface. + + +---- + + +Order II. PHAEOSPHAERIA, Haeckel, 1879. + +_Definition._--PHAEODARIA with a simple or double, usually spherical +lattice-shell, which is not bivalved and has no peculiar mouth or +peristome. Central capsule placed in the centre of the shell. + + + +Family LXXIV. #OROSPHAERIDA#, n. fam. (Pls. 106, 107). + +_Definition._--PHAEODARIA with a big spherical (sometimes polyhedral or +ellipsoidal), very coarse shell, which is composed of thick bars containing +an axial canal. Nodal points of the coarse network without astral septa. +Meshes of moderate size, irregularly polygonal. Surface of the shell +usually with radial spines and pyramidal elevations. No peculiar mouth in +the shell. Central capsule tripylean, in the centre of the shell. + +The family #Orosphaerida# comprises those PHAEODARIA which possess a simple +spherical or polyhedral lattice-shell, composed of hollow, very thick, +non-articulate rods, without a peculiar shell-mouth. They agree in the +considerable size of the spherical lattice-shell and the absence of a +peculiar shell-mouth with the other #Phaeosphaeria#, but differ from them +in the coarse and irregular shape of the massive network, which is composed +of irregular polygonal meshes, separated by very thick concentrically +stratified rods, containing a fine axial canal. The closely allied +Sagosphaerida differ from them in the delicate shape of the solid and very +thin, filiform rods of the network, and its subregular {1591}triangular +meshes. The Aulosphaerida differ in the development of the peculiar nodal +cavities and astral septa, by which the thin-walled cylindrical tubes of +the articulated network are separated in the stellate nodal points. The +Cannosphaerida, closely allied to these latter, also differ in the +articulated network, and further in the possession of an internal +concentric shell. The Castanellida are sometimes similar to the +Orosphaerida, but distinguished by a peculiar large shell-mouth and a +network of different shape. + +The Orosphaerida belong to the biggest Radiolaria, and the lattice-work of +their spherical shell is of a ruder and coarser shape than in any of the +other families of this class. Nevertheless they have been hitherto +perfectly unknown, and were first discovered by the Challenger. We have +been able to distinguish in the collection four genera and twenty-seven +species. This strange fact may be explained by the circumstance, that they +are in general rare, and restricted to a few localities, and that probably +all the species are inhabitants of great depths. Complete shells also are +rarely found, whilst broken fragments of their big shells, easily +recognisable by the coarse irregular meshes and the thick stratified bars, +are met with frequently in the Radiolarian ooze of some Pacific Stations, +especially at Stations 265 and 268, at a depth of 2900 fathoms. + +The lattice-shell of the Orosphaerida is usually spherical, or an +endospherical polyhedron (Pl. 106, fig. 4); rarely one axis is somewhat +prolonged, so that the shell becomes slightly ellipsoidal (Pl. 106, fig. +1). Its diameter is usually between 2 and 3, often also between 2 and 1 +mm., rarely more than 3, or less than 1 mm. The largest shells observed +attained 5 to 6, the smallest 0.5 to 0.6 mm. Their general habit is very +characteristic, so that they may be easily distinguished from all other +spherical lattice-shells, especially from the Castanellida and from the +simple Monosphaerida (_Cenosphaera_, _Acanthosphaera_), with which I +confounded them in the beginning (hence the first shell observed, figured +in 1878, was placed among the Monosphaerida in Pl. 12). A closer +examination of the coarse network and of the peculiar structure of its +thick bars always enables one to recognise even small isolated fragments of +broken shells. + +The meshes of the coarse network exhibit in all observed Orosphaerida a +very irregular form and unequal size; the majority are usually more or less +quadrangular, more rarely they are triangular, pentagonal or hexagonal, +very rarely rounded. They are often arranged in parallel rows, which seem +to be determined by prominent crests, connecting the bases of the radial +spines (Pl. 12, fig. 1; Pl. 106, fig. 4, &c.). The diameter of the meshes +is usually between 0.05 and 0.1, often 0.1 to 0.2, rarely more than 0.25, +or less than 0.025 mm. In _Oroplegma_, which develops an outer loose, +spongy shell around the inner primary shell, the big meshes of the former +become much larger and very irregular (Pl. 107, fig. 1). + +The coarse bars which separate the large meshes of the irregular network +are very thick and massive, cylindrical, usually of unequal thickness, +straight or slightly curved, never angular or prismatic. Their diameter is +usually between 0.01 and 0.02, rarely {1592}more than 0.03 or less than +0.005 mm. Their surface is either smooth or slightly spinulate. Examined in +the dry state and by strong lenses, they constantly exhibit a fine, but +distinct longitudinal striation, as the expression of concentric +stratification. A fine axial canal or central tubule is usually visible in +the axis of each rod, and often this axial canal is studded with numerous +short lateral branches (Pl. 107, figs. 2, 4, 8). But very often the axial +canals become rudimentary or lost, or are developed only in a part of the +bars (Pl. 12, fig. 1). When they are completely developed, the entire +network of the shell is drained by a reticulate system of communicating +axial canals; they are probably filled by jelly in the living body. This +tubular system never attains that regularity and high development which is +constantly found in the Aulosphaerida; and the characteristic stellate +nodal points of the latter, with their astral septa, are never found in any +of the Orosphaerida. Moreover the wall of the tubular bars is very thin and +structureless in the Aulosphaerida, very thick and stratified in the +Orosphaerida, the enclosed canal very wide in the former, very narrow in +the latter. The stratification of the concentric cylindrical lamellae, +which surround the narrow axial canal, is effected by the gradual +deposition of the concentric layers, and is very similar to that which is +found in the thick spicula of many sponges. The peculiar structure of the +bars in the Orosphaerida becomes very distinct if the skeleton be burned, +or acted upon by fire for some time; it then assumes a brown colour and its +surface often appears dimpled. Sometimes the concave dimples on the surface +of the bars are rather deep and separated by prominent crests (Pl. 107, +figs. 4, 7). The few genera of Orosphaerida which are here distinguished +have all the same structure, are closely allied, and differ mainly in the +shape of the outer surface of the lattice-sphere. The latter is quite +simple and smooth only in _Orona_. In the common _Orosphaera_ (Pl. 106, +figs. 1-3) it is studded with radial spines. In the most frequent form, +_Oroscena_, the shell has a pyramidal or tent-shaped elevation on the base +of each radial spine, and usually the bases of the neighbouring spines are +connected by strong prominent crests, the edges of the three-sided or +four-sided pyramids (Pl. 12, fig. 1; Pl. 106, fig. 4). This remarkable form +is more or less polyhedral, with concave sides, and is similar to the +characteristic shells which are represented by _Auloscena_ among the +Aulosphaerida, by _Sagoscena_ and _Sagoplegma_ among the Sagosphaerida +(compare Pls. 108 and 110). The pyramids or tents, however, are in these +latter more regularly and distinctly developed than in the Orosphaerida. +The radial spines which arise form the top of the pyramids are often +branched, and the branches become connected to form an outer enveloping +secondary shell or a loose spongy framework in _Oroplegma_ (Pl. 107, fig. +1). + +The radial spines of the Orosphaerida never exhibit a constant number or +disposition in the individual species; their usual number is from twenty to +sixty. Their form exhibits two different types, which, however, are not +sharply separated; robust club-shaped and slender rod-shaped spines. The +robust club-shaped spines are usually about as long as {1593}the diameter +of the shell; they are longitudinally striped in the basal part, spinulate +or reticulately dimpled in the distal part; sometimes they are straight, at +other times curved or undulate (Pl. 106, figs. 1-4; Pl. 107, figs. 4-6). +The slender rod-shaped spines are usually longer than the diameter of the +shell, cylindrical, more or less curved or even undulate, smooth or thorny, +sometimes irregularly branched, and often the branches are all or partly +connected (Pl. 106, fig. 3; Pl. 107, fig. 1). In the majority of the shells +observed the radial spines were found to be partly broken off. Their +structure is the same as that of the bars of the network; but the central +axial canal and the surrounding concentric lamellae are usually more +distinct than in the latter. + +The central capsule of the Orosphaerida lies in the centre of the spherical +lattice-shell, surrounded by the voluminous calymma, which fills up its +cavity. The form, structure, and size of the central capsule are the same +as in the closely allied Aulosphaerida (Pl. 111, fig. 2). Its diameter is +usually about 0.2, or between 0.15 and 0.25, rarely more than 0.3 or less +than 0.12. The dark phaeodium is of about the same volume as the central +capsule, and envelops its oral half with the radiate operculum and the +proboscis of the astropyle. The two opposite parapylae are small. + +_Synopsis of the Genera of Orosphaerida._ + + I. Subfamily { Surface smooth, without + Oronida. { radial spines, 671. _Orona_. + Surface of the shell { + without pyramidal { Surface studded with simple or + or tent-shaped { branched radial spines, 672. _Orosphaera_. + elevations. { + + II. Subfamily { Pyramids of the surface free, + Oroscenida. { without spongy envelope, 673. _Oroscena_. + Surface of the shell { + with numerous { Pyramids of the surface + pyramidal or tent- { connected by a spongy + shaped elevations. { envelope or an external + { lattice-shell, 674. _Oroplegma_. + + + +Genus 671. _Orona_,[289] n. gen. + +_Definition._--#Orosphaerida# with a simple spherical or slightly +ellipsoidal shell, without pyramidal elevations and radial spines. + +The genus _Orona_ is the simplest of the Orosphaerida, and probably the +common ancestral form of this family. The lattice-shell is a simple +fenestrated sphere, sometimes slightly ellipsoidal, with prolonged main +axis, and bears on its surface neither tent-shaped elevations nor radial +spines. It may be confounded with some big forms of _Cenosphaera_; it +differs, however, in the possession of hollow central canals in the thick +bars of the very coarse lattice-plate. + + +{1594}1. _Orona maxima_, n. sp. (Pl. 107, fig. 5). + +Shell spherical, with very irregular polygonal meshes. Bars of the loose +network smooth or slightly spinulate, very thick, with a pinnulate axial +canal. + +_Dimensions._--Diameter of the sphere 5.0 to 5.5, of the meshes 0.2 to 0.4, +of the bars 0.01. + +_Habitat._--Central Pacific, Station 265, depth 2900. + + +2. _Orona robusta_, n. sp. + +Shell spherical, with irregular quadrangular meshes (intermingled with +single triangular, pentagonal, and hexagonal meshes). Bars of the coarse +network very thick, spinulate. + +_Dimensions._--Diameter of the sphere 3.0 to 3.6, of the meshes 0.05, of +the bars 0.012. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +3. _Orona crassissima_, n. sp. (Pl. 107, fig. 7). + +Shell ellipsoidal, slightly prolonged in the main axis, with irregular +polygonal meshes of very different sizes and unequal forms. Bars of the +coarse network very thick, thorny and dimpled, their surface being covered +with a network of prominent polygonal crests. + +_Dimensions._--Diameter of the sphere 3.0 to 4.0, of the meshes 0.2 to 0.5, +of the bars 0.02 to 0.06. + +_Habitat._--South Pacific, Station 289, depth 2550 fathoms. + + + +Genus 672. _Orosphaera_,[290] n. gen. + +_Definition._--#Orosphaerida# with a simple, spherical (sometimes slightly +ellipsoidal or polyhedral) lattice-shell without pyramidal elevations, but +with numerous radial spines. + +The genus _Orosphaera_ differs from the preceding _Orona_, its ancestral +form, in the development of simple or branched radial spines. It bears, +therefore, the same relation to the latter that _Acanthosphaera_ has to +_Cenosphaera_. In the two latter genera, however, the bars of the network +are solid, in the two former hollow. The species referred to _Orosphaera_ +are closely allied and require a further accurate examination. + + + +Subgenus 1. _Oronium_, Haeckel. + +_Definition._--Radial spines simple, smooth or spiny, but neither branched +nor arborescent. + + +{1595}1. _Orosphaera hastigera_, n. sp. + +Radial spines cylindrical, straight, smooth, simple, about as long as the +diameter of the spherical shell, and as broad as its smooth bars. Meshes of +the network irregularly polygonal, the majority quadrangular, of different +sizes. + +_Dimensions._--Diameter of the sphere 1.0 to 1.2, length of the radial +spines 1.1 to 1.5, middle breadth 0.004. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +2. _Orosphaera spinigera_, n. sp. + +Radial spines cylindrical, irregularly curved, thorny, simple, two to three +times as long as the diameter of the spherical shell, and as broad as its +spiny bars. Meshes of the network irregularly polygonal, the majority +pentagonal. + +_Dimensions._--Diameter of the sphere 1.5 to 1.8, length of the spines 3.0 +to 5.0, breadth 0.006. + +_Habitat._--North Atlantic, Station 353, depth 2965 fathoms. + + +3. _Orosphaera fusigera_, n. sp. + +Radial spines slender, spindle-shaped, straight, smooth, about as long as +the diameter of the spherical or slightly ellipsoidal shell, in the thicker +middle part five times as broad as the bars, and tapering equally towards +both ends. Meshes of the network irregularly polygonal, the majority +quadrangular, separated by smooth bars. + +_Dimensions._--Diameter of the shell 1.0 to 1.2, length of the spines 1.2 +to 1.6, basal breadth 0.02, middle breadth 0.1. + +_Habitat._--North Pacific, Station 253, depth 3125 fathoms. + + +4. _Orosphaera foveolata_, n. sp. + +Radial spines spindle-shaped, straight, dimpled, half as long as the radius +of the spherical shell and three to five times as thick as the bars. Meshes +irregular, polygonal, of very different shapes, separated by dimpled bars. +(Similar to _Oroscena gegenbauri_, Pl. 106, fig. 4, but with spherical +dimpled shell, without pyramidal elevations.) + +_Dimensions._--Diameter of the shell 2.0 to 2.4, length of the spines 0.5, +breadth 0.15. + +_Habitat._--Central Pacific, Station 267, depth 2700 fathoms. + + +5. _Orosphaera serpentina_, n. sp. (Pl. 106, fig. 1). + +Radial spines cylindrical, dimpled, undulate or curved in a snake-like +manner, about as long as the diameter of the ellipsoidal or spherical shell +and four to six times as broad as its smooth bars. Meshes very irregular, +polygonal. + +_Dimensions._--Diameter of the shell 1.0 to 1.2, length of the spines 0.12 +to 0.15, breadth 0.12. + +_Habitat._--South Pacific, Station 289, depth 2550 fathoms. + + +{1596}6. _Orosphaera horrida_, n. sp. (Pl. 106, fig. 2). + +Radial spines club-shaped, very strong, straight, about as long as the +diameter of the polyhedral shell, ovate and smooth in the distal half, +slenderly conical, and armed with recurved spines in the proximal half; +their outer third is the thickest, and five times as broad as the smooth +bars of the coarse network. Meshes of the latter irregularly quadrangular. + +_Dimensions._--Diameter of the shell 1.2 to 1.6, length of the spines 1.2 +to 2.0, breadth 0.2. + +_Habitat._--South Pacific, Station 291, depth 2250 fathoms. + + +7. _Orosphaera clavigera_, n. sp. + +Radial spines club-shaped, thickened towards the distal end, more or less +curved, spinulate, about as long as the diameter of the spherical shell; in +the distal third four to six times as broad as the spinulate bars. Meshes +irregularly polygonal, the majority pentagonal. + +_Dimensions._--Diameter of the shell 2.0 to 2.5, length of the spines 1.8 +to 2.2, breadth 0.16. + +_Habitat._--Central Pacific, Station 263, depth 2650 fathoms. + + + +Subgenus 2. _Orothamnus_, Haeckel. + +_Definition._--Radial spines branched or arborescent. + + +8. _Orosphaera ramigera_, n. sp. + +Radial spines cylindrical, spinulate, straight, about twice as long as the +diameter of the spherical shell and as thick as its spinulate bars. +Numerous simple spinulate branches, straight or slightly curved, and two to +four times as long as the meshes, are irregularly scattered, and arise +nearly perpendicularly from the bars. + +_Dimensions._--Diameter of the shell 2.0 to 2.2, length of the spines 4 to +5, breadth 0.05. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +9. _Orosphaera furcata_, n. sp. + +Radial spines cylindrical, smooth, irregularly curved, about as long as the +radius of the spherical shell and as thick as its smooth bars, forked at +the distal end, with two or three terminal branches of various lengths. +Meshes irregularly polygonal (the majority hexagonal). + +_Dimensions._--Diameter of the shell 1.2, length of the spines 0.7, breadth +0.03. + +_Habitat._--Indian Ocean, Madagascar (Rabbe), surface (?). + + +10. _Orosphaera confluens_, n. sp. + +Radial spines cylindrical, smooth, irregularly curved, two to three times +as long as the diameter of the polyhedral shell, twice as broad as its +smooth bars, bearing numerous irregular, lateral {1597}branches, which are +partly confluent and fenestrated (similarly as in Pl. 107, fig. 1), but not +forming an outer lattice-shell. Meshes irregularly polygonal. + +_Dimensions._--Diameter of the shell 3.3, length of the spines 6 to 9, +breadth 0.03. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + +11. _Orosphaera arborescens_, n. sp. (Pl. 106, fig. 3). + + _Orothamnus arborescens_, Haeckel, 1881, Atlas, loc. cit. + +Radial spines cylindrical, rough, more or less curved, somewhat longer than +the diameter of the subspherical or slightly ellipsoidal shell, and at the +thicker base three times as broad as its smooth bars, bearing numerous +irregularly branched and curved, sometimes confluent, lateral branches. +Meshes irregularly quadrangular. + +_Dimensions._--Diameter of the shell 1.2 to 1.6, length of the spines 1.5 +to 2.2, breadth 0.06. + +_Habitat._--South Atlantic, Station 335, depth 1425 fathoms. + + + +Genus 673. _Oroscena_,[291] n. gen. + +_Definition._--#Orosphaerida# with a simple, polyhedral or subspherical +lattice-shell, and with numerous pyramidal elevations on its surface, the +top of which bears a radial spine. + +The genus _Oroscena_ differs from the preceding _Orosphaera_ in the +possession of numerous pyramidal or tent-shaped elevations, each of which +bears on its top a radial spine. It exhibits therefore the same relation to +the latter that _Sagoscena_ does to _Sagosphaera_ and _Auloscena_ to +_Aulosphaera_. The bases of the radial spines are usually connected by +prominent concave crests, the edges of the pyramids. The species described +of _Oroscena_ seem to be very variable and transformistic. + + + +Subgenus 1. _Oroscenium_, Haeckel. + +_Definition._--Radial spines simple, smooth or spiny, but neither branched +nor forked. + + +1. _Oroscena gegenbauri_, n. sp. (Pl. 106, fig. 4). + +Radial spines club-shaped, about half as long as the radius of the shell, +cylindrical and finely sulcate in the basal third, ovate and elegantly +dimpled in the distal two-thirds. The bases of the radial spines are +connected by prominent concave crests, which form the edges of the +polyhedral shell. Meshes irregularly polygonal, the majority quadrangular, +separated by denticulate bars. + +{1598}_Dimensions._--Diameter of the shell (without spines) 1.2 to 1.8, of +the meshes 0.04 to 0.1; length of the spines 0.3 to 0.5. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +2. _Oroscena muelleri_, n. sp. (Pl. 107, fig. 8).[292] + +Radial spines club-shaped, very similar to that of the preceding species, +but much larger, about as long as the radius of the shell. Meshes +irregularly polygonal, the majority pentagonal, separated by smooth bars. + +_Dimensions._--Diameter of the shell 2.0 to 2.4, length of the spines 1.0 +to 1.2. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +3. _Oroscena cuvieri_, n. sp. (Pl. 107, fig. 6). + +Radial spines club-shaped, compressed and smooth in the proximal half, +spindle-shaped and dimpled in the distal half, about as long as the radius +of the shell. Meshes irregularly polygonal, the majority hexagonal, +separated by denticulate bars. + +_Dimensions._--Diameter of the shell 1.5, length of the spines 0.8. + +_Habitat._--South Pacific, Station 289, depth 2550 fathoms. + + +4. _Oroscena baerii_, n. sp. (Pl. 107, fig. 4). + +Radial spines nearly spindle-shaped, undulate, tapering from the thicker +middle towards both ends, coarsely dimpled, about one-third as long as the +radius of the shell. Meshes irregularly polygonal, the majority pentagonal, +separated by spinulate bars. + +_Dimensions._--Diameter of the shell 3.2, length of the spines 1.0 to 1.2, +breadth 0.1. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +5. _Oroscena wolffii_, n. sp. + +Radial spines cylindrical, spinulate, more or less curved, longer than the +diameter of the shell and about twice as broad as its bars. Meshes +irregularly polygonal, of very variable form and unequal size, separated by +smooth bars. + +_Dimensions._--Diameter of the shell 2.5, length of the spines 3.0 to 3.5, +breadth 0.02. + +_Habitat._--Indian Ocean, Zanzibar (Pullen), depth 2200 fathoms. + + + +Subgenus 2. _Orodendrum_, Haeckel. + +_Definition._--Radial spines branched or arborescent. + + +{1599}6. _Oroscena huxleyi_, n. sp. (Pl. 12, figs. 1, 1_a_). + +Radial spines cylindrical, obliquely ascending and irregularly curved, +about as long as the diameter of the shell and somewhat thicker than its +thorny bars. A variable number of short, irregular, partly simple, partly +forked, lateral branches arises from the spines. Meshes of the network very +irregular, partly solid, partly hollow (fig. 1_a_*), the majority +quadrangular. This species, the first observed form of Orosphaerida +(captured the 21st February 1873 at Station 5), was at the beginning of my +observations, in 1876, and when I had no knowledge of the central capsule, +erroneously regarded by me as a gigantic Sphaeroid (of the Monosphaerida) +and therefore placed in Pl. 12. The long branched spines, afterwards +observed complete in another specimen, were broken off in the specimen +first figured. + +_Dimensions._--Diameter of the shell 2.0 to 2.5, length of the spines 2 to +3 mm., breadth 0.03. + +_Habitat._--North Atlantic (west of Canary Islands), Station 5, depth 2740 +fathoms. + + +7. _Oroscena darwinii_, n. sp. + +Radial spines cylindrical, irregularly curved and branched, about twice as +long as the diameter of the shell; the branches are all again ramified and +partly confluent (as in Pl. 107, fig. 1). The branches and the bars of the +network are of equal breadth, smooth (not thorny as in the similar +preceding species). Meshes rather subregular, quadrangular. + +_Dimensions._--Diameter of the shell 2.4 to 2.8, length of the spines 4 to +5 mm., breadth 0.015. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms. + + +8. _Oroscena duncanii_, n. sp. + + ? _Hexactinellida dictyonina_, Martin Duncan, 1881, Journ. Roy. Micr. + Soc., p. 175, pl. iii. figs. 4, 6. + +Radial spines cylindrical, thorny, arborescent, somewhat shorter than the +diameter of the shell, with irregular ramified branches (similar to +_Orosphaera arborescens_, Pl. 106, fig. 3). The size and ramification of +the arborescent spinulate branches decrease towards the apex. The thicker +branches are from two to three times as broad as the spinulate bars of the +network. Meshes of the latter irregular, the majority quadrangular. + +_Dimensions._--Diameter of the shell 3.2, length of the spines 3.5 to 4.5, +breadth 0.02 to 0.3. + +_Habitat._--South Atlantic, Station 318, depth 2040 fathoms; coast of +Portugal, 1095 fathoms. + + + +Genus 674. _Oroplegma_,[293] n. gen. + +_Definition._--#Orosphaerida# with a spongy, spherical or slightly +polyhedral lattice-shell, which is enveloped by a loose spongy framework +and bears numerous radial spines. + +The genus _Oroplegma_ differs from the other Orosphaerida in the +development of an external lattice-work enveloping the internal primary +shell, and produced by the union {1600}of the branches of the radial +spines. This outer shell is either a simple lattice-plate (comparable to +the cortical shell of _Diplosphaera_), or a spongy framework (as in +_Rhizoplegma_). + + + +Subgenus 1. _Oroplegmium_, Haeckel. + +_Definition._--External shell a simple fenestrated lamella, forming an +outer concentric lattice-sphere around the inner primary shell. + + +1. _Oroplegma diplosphaera_, n. sp. (Pl. 107, fig. 1). + +Radial spines slender, cylindrical, smooth, more or less curved, about +twice as broad as the smooth bars of the network. External shell a simple +irregular lattice-sphere, with loose polygonal meshes, which are on an +average three to four times as broad as the irregular meshes of the +internal shell. The free prominent parts of the radial spines are +irregularly branched, very long, with partly confluent branches. + +_Dimensions._--Diameter of the inner sphere 1.5 to 2.0, of the outer 2.5 to +3.0; length of the free spines 1.2, breadth 0.04. + +_Habitat._--Central Pacific, Station 265, depth 2900 fathoms. + + +2. _Oroplegma spinulosum_, n. sp. + +Radial spines slender, cylindrical, thorny, more or less curved, very +similar to those of the preceding species; the shell also much resembles +that of _Oroplegma perplexum_. It differs from the latter in the more +regular fenestration of both shells, and mainly in the shape of the bars +and the spine-branches, which are all spinulate and densely studded with +small conical thorns. + +_Dimensions._--Diameter of the inner sphere 1.5 to 2.0, of the outer 2.5 to +3.0; length of the spines 1.2, breadth 0.03. + +_Habitat._--Central Pacific, Station 268, depth 2900 fathoms. + + +3. _Oroplegma velatum_, n. sp. + +Radial spines stout, cylindrical, somewhat club-shaped, spiny, slightly +curved, about three to four times as broad as the thorny bars of the +network. External shell a simple lattice-sphere with irregular polygonal +meshes, which are for the most part pentagonal and about four times as +broad as the polygonal meshes of the inner shell. The free prominent parts +of the radial spines are thickened, club-shaped, and about as long as the +radius. + +_Dimensions._--Diameter of the inner sphere 2.0 to 2.4, of the outer 2.8 to +3.6; length of the free spines 0.5 to 0.7, breadth 0.12 to 0.15. + +_Habitat._--Tropical Atlantic, Station 338, depth 1990 fathoms. + + + +{1601}Subgenus 2. _Orodictyum_, Haeckel. + +_Definition._--External shell a complex framework, forming an outer spongy +envelope around the inner primary shell. + + +4. _Oroplegma spongiosum_, n. sp. (Pl. 107, fig. 3). + +Radial spines stout, cylindrical, spinulate, slightly curved, three to five +times as broad as the inner rough bars. External shell with pyramidal +elevations, forming a loose spongy framework, the irregular polygonal +meshes of which are two to five times as broad as those of the enclosed +internal shell; the thickness of the spongy envelope equals about half the +radius of the inner shell. External free prolongations of the radial spines +about equal to the radius. + +_Dimensions._--Diameter of the inner sphere 2 to 2.5, of the outer 3 to +3.5; length of the free radial spines 0.5 to 2.0, breadth 0.1. + +_Habitat._--North Pacific, Station 241, depth 2300 fathoms. + + +5. _Oroplegma giganteum_, n. sp. (Pl. 107, fig. 2). + +Radial spines slender, cylindrical, spinulate, irregularly curved, about +twice as broad as the spinulate tubular bars of the network (fig. 2). +External shell an irregular, loose, spongy framework, the polygonal meshes +of which are three to six times as broad as the rounded irregular meshes of +the inner shell; the thickness of the spongy envelope about equals the +radius of the inner shell. External free prolongation of the radial spines +irregularly branched. + +_Dimensions._--Diameter of the inner sphere 3.2 to 3.5, of the outer 5.4 to +6.6; length of the free spines 1.4 to 1.5, breadth 0.03. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + + +Family LXXV. #SAGOSPHAERIDA#, n. fam. (Pl. 108). + +_Definition._--PHAEODARIA with a large spherical (or sometimes polyhedral), +very delicate shell, which is composed of solid, very thin and long +threads. Nodal points of the arachnoidal network without astral septa. +Meshes large, triangular. Surface of the shell usually armed with radial +spines and often studded with pyramidal elevations. No peculiar mouth in +the shell. Central capsule tripylean, in the centre of the shell. + +The family #Sagosphaerida# comprises a rather large number of common and +widely distributed PHAEODARIA, which in respect of the special form and +differentiation of the shell exhibit the greatest similarity to the common +Aulosphaerida, but differ essentially from them in the peculiar structure +of the network. This is not composed of stout hollow cylindrical tubes, but +of solid, very thin threads; and these fine arachnoidal {1602}threads are +simply united or confluent at the nodal points, and are not connected by a +radial or stellate septal junction, as in the Aulosphaerida. There are, +therefore, neither astral septa nor a nodal cavity in each nodal point. The +delicate shape of the thin and fragile threads separates the Sagosphaerida +from the closely allied Orosphaerida, the thick bars of which contain a +central axial canal and exhibit a concentric structure. Another difference +between these two similar families is indicated by the form of the meshes +of the network, which are constantly triangular in the Sagosphaerida, but +irregularly polygonal or quadrangular in the Orosphaerida. The general +habit of these two families, however, is very different, since the big and +stout spheres of the Orosphaerida are the coarsest and rudest spherical +shells of all Radiolaria, whilst the fragile and delicate spheres of the +Sagosphaerida represent the finest and most tender in the whole class. + +The spherical lattice-shell of the Sagosphaerida has a considerable size, +its diameter being usually between one and three millimetres, rarely less +or more. Some species are very common and widely distributed, usually +accompanying the common Aulosphaerida; very frequently the similar shells +of the two are found interwoven. But in spite of this frequency and visible +size, the Sagosphaerida have hitherto almost completely escaped the +attention of observers. The main cause of this strange fact may be their +extreme delicacy and fragibility, so that complete and intact shells occur +very rarely, the majority being more or less broken and incomplete. It +seems that only two species of Sagosphaerida have been hitherto observed. + +The first form described is _Sagmarium trigonizon_, observed by me in 1859 +living at Messina, and figured in 1862 in my Monograph as _Dictyosoma +trigonizon_ (Taf. xxvi. figs. 4-6), but afterwards called _Spongodictyum +trigonizon_ (_loc. cit._, p. 459). I supposed at that time (now twenty-five +years ago), that this remarkable and in many respects distinct form might +belong to the Spongosphaerida, and that an internal, triple, spherical +lattice-shell, found entangled in its spongy framework, might be its +central "medullary shell." But at present, having found many shells of +different Radiolaria accidentally entangled in the arachnoidal framework of +various Sagosphaerida, I think it much more probable, that that "triple +medullary shell," composed of three simple concentric lattice-spheres, was +really a species of _Plegmosphaera_ or _Actinomma_, accidentally entangled +in the arachnoidal spongy framework of _Sagmarium_. This is the more +probable, as I had observed very frequently at Messina, in 1859, fragments +of that framework, but only once the triple lattice-shell which I supposed +to be the "triple medullary shell" of the former. The peculiar structure of +the loose framework, its very large triangular meshes and thin arachnoidal +bars, partly provided with cruciate verticils (_loc. cit._, Taf. xxvi. +figs. 4, 5) have been very frequently observed by me during the last ten +years in various Sagosphaerida (PHAEODARIA), but never in any true +#Sphaeroidea# (SPUMELLARIA). + +The second species of Sagosphaerida hitherto observed, is _Sagoscena +gracilis_, described and figured in 1879 by Richard Hertwig as _Aulosphaera +gracilis_ (Organism. {1603}d. Radiol., p. 91, Taf. ix. fig. 4). He too +observed only fragments of destroyed and incomplete shells, and was led by +their striking similarity to fragments of _Aulosphaera elegantissima_ to +unite it with the genus _Aulosphaera_. But the accurate description and the +figure given by him of the fragments observed leaves no doubt that it was a +true _Sagoscena_. + +In the collection of the Challenger the Sagosphaerida are so common and so +richly represented, that we may describe here not less than seven genera +and thirty-three species, but this may be a small part only of the numerous +species of this family, which seems to be widely distributed over all +oceans, in the Arctic and Antarctic as well as in temperate and tropical +zones. The majority are inhabitants of the surface, but a few species have +been found only in deep-sea soundings. A striking fact is their usual +association with the similar Aulosphaerida. The majority of shells of both +families were found entangled in one another. + +The shell of all Sagosphaerida seems to be spherical or nearly spherical in +the complete state; but complete spheres can be observed only very rarely, +and it is not impossible that deviations from the spherical form exist just +as in some Aulosphaerida (_e.g._, the lenticular _Aulophacus_ and the +spindle-shaped _Aulatractus_). The diameter of the spheres usually seems to +be between 1 and 2, often also 3 millimetres; very rarely shells occur +which are less than 1 or more than 3 (4 or 5) millimetres. + +The siliceous network or lattice-work of the Sagosphaerida exhibits a very +characteristic shape, and this enables one to distinguish it at first sight +from all the other Radiolaria. It is constantly composed of triangular, +very large meshes, which are separated by very thin and delicate, flexible +and elastic bars. With respect to the arrangement of these meshes we +distinguish two different subfamilies; in the Sagenida the wall of the +spherical shell is very thin and composed only of a simple lattice-plate; +in the Sagmarida the wall is thickened and spongy, with a complete +wicker-work of threads, interwoven in different directions. + +The typical triangular form of the large meshes is usually regular or +subregular in the fenestrated Sagenida, more or less irregular in the +spongy Sagmarida. In many cases, however, irregular triangles also occur in +the former, and regular triangles in the latter subfamily. Very rarely +irregular polygonal meshes are found in a part of the network, small +connecting bars being developed accidentally between two neighbouring sides +of the triangles. The diameter of the meshes is usually between 0.1 and 0.2 +mm., often also greater, between 0.2 and 0.3, rarely smaller, 0.05 to 0.09 +mm. The triangular meshes of the Sagosphaerida are therefore on an average +ten times as large as the usual meshes in the network of the common +#Sphaeroidea#. + +The filiform bars, or the thread-shaped, very long and thin rods between +the triangular meshes, are scarcely less characteristic of the +Sagosphaerida than the form and size of the meshes. Their length is usually +between 0.1 and 0.2 mm., often also {1604}from 0.2 to 0.3 mm., whilst their +thickness is only 0.002 to 0.004 mm., often it is less than 0.001, rarely +more than 0.005 mm. The nodal points of the network, in which six threads +are usually united, are more or less thickened, often stellate (Pl. 108, +figs. 9, 12, &c.). Sometimes they are pierced by a central pore. The thin +threads are constantly cylindrical, never edged or prismatic, very elastic +and flexible; usually they are perfectly smooth, rarely spiny or thorny, +sometimes provided with scattered cruciate verticils of lateral branches, +as in _Sagena crucifera_ and in the first described form of this family, +_Sagmarium trigonizon_ (compare my Monograph, 1862, Taf. xxvi. fig. 5). + +The surface of the spherical shell is smooth only in two genera of +Sagosphaerida, in _Sagena_ and _Sagmarium_ (Pl. 108, figs. 2, 8). In the +five other genera it is covered either with radial spines, arising from the +nodal points of the network, or with peculiar cortical pyramids or +tent-shaped elevations (Pl. 108, figs. 1, 3-6, &c.). These pyramids are of +the same characteristic shape as in the similar _Auloscena_ among the +Aulosphaerida (Pl. 110, fig. 1); usually, however, they are less regular +than in the latter. The pyramids or tents are usually six-sided, often, +however, they are also four-sided or three-sided, more rarely five, seven +or more sided. The edges of the pyramids are formed by filiform bars +similar to those which compose the original lattice-work of the +Sagosphaerida. The cavity of the pyramids is quite simple in _Sagoscena_ +(figs. 1, 5, 6), whilst in _Sagenoscena_ and _Sagoplegma_ a radial column +arises in its axis, the thickened axial rod (figs. 3, 4, 10). + +The radial spines, which arise either from the tops of the pyramids or from +the nodal points of the network, exhibit in the Sagosphaerida a variety and +elegance similar to the closely allied Aulosphaerida. Sometimes a single +radial spine arises in each nodal point or at the top of each pyramid +(figs. 3, 4, 10); at other times two, three, or four (rarely more) +divergent spines (figs. 6-9, 12, 13). These are rarely quite simple, +usually provided with lateral and terminal branches. The lateral branches +are either scattered irregularly, or regularly disposed in elegant +verticils, each of which is usually composed of three or four short +branches (Pl. 108, figs. 9, 13). The terminal branches form either a +similar verticil, or a bunch or corona, composed of numerous radial +secondary spines. The distal ends of the terminal as well as of the lateral +branches are rarely simple, usually they are provided with a spinulate knob +or with an elegant spathilla (Pl. 108, figs. 3, 9, 13). + +The _central capsule_ of the Sagosphaerida is comparatively small, as it +also is in the Aulosphaerida and Orosphaerida. Its diameter is usually +about one-third or one-fourth that of the enveloping shell, between 0.2 and +0.3, often only 0.12 to 0.18, rarely more than 0.3 mm. It is surrounded on +the oral half by a red or dark phaeodium and separated from the inner +surface of the shell by the voluminous calymma. The subspherical nucleus is +usually about half as broad as the capsule. The three openings of the +latter, the large tubular astropyle and the two opposite lateral parapylae, +exhibit the same shape {1605}as in the closely allied Aulosphaerida (Pl. +111, fig. 3). The pseudopodia arising from the central capsule form a loose +network in the calymma, and proceed over its surface as numerous delicate +radial filaments, often supported by the radial spines. + +_Synopsis of the Genera of Sagosphaerida._ + + ------------------------------------------------------------------------- + I. Subfamily Sagenida. + Wall of the spherical shell composed of a simple lattice-plate with + or without pyramidal elevations. + ------------------------------------------------------------------------- + { No radial spines, surface + Surface of the spherical { smooth, 675. _Sagena_. + shell smooth or spiny, { + without pyramidal { Radial spines in the nodal + elevations. { points, 676. _Sagosphaera_. + + Surface of the spherical { Pyramids without internal + shell covered with { axial rod, 677. _Sagoscena_. + pyramidal or tent- { + shaped elevations. { Pyramids with an internal + { radial axial rod, 678. _Sagenoscena_. + ------------------------------------------------------------------------- + II. Subfamily Sagmarida. + Wall of the spherical shell spongy, composed of an irregular + complicated wicker-work. + ------------------------------------------------------------------------- + Surface of the spherical { Surface smooth, without + shell smooth or spiny, { radial spines, 679. _Sagmarium_. + without pyramidal { + elevations. { Surface studded with + { radial spines, 680. _Sagmidium_. + + Surface of the spherical { Pyramids on the top with a + shell covered with { radial spine or a bunch + pyramidal elevations. { of divergent spines, 681. _Sagoplegma_. + + + +Subfamily 1. SAGENIDA, Haeckel. + +_Definition._--#Sagosphaerida# with a delicate spherical shell, the thin +wall of which is composed of a simple lattice-plate, not spongy. + + + +Genus 675. _Sagena_,[294] n. gen. + +_Definition._.--#Sagosphaerida# with a delicate shell, the thin wall of +which is composed of a simple smooth lattice-plate, without radial spines. + +The genus _Sagena_ is the simplest of the Sagosphaerida and may be regarded +as the common ancestral form of this family. The delicate wall of the +simple spherical lattice-shell is composed of large, regular, or +subregular, triangular meshes, the nodal points of which bear no radial +spines. It agrees therefore perfectly with _Aularia_, and differs from this +simplest form of Aulosphaerida only in the structure of the skeleton, which +is composed not of hollow articulated tubes, but of very thin solid +threads. The skeleton may therefore also be confounded with _Cenosphaera_, +but the central capsule of this latter is "peripylean," with numerous fine +pores in the entire wall, whilst that of _Sagena_ is "tripylean," having +the proboscis of all PHAEODARIA. + + +{1606}1. _Sagena ternaria_, n. sp. (Pl. 108, fig. 8). + +Network subregular, with equilateral triangular meshes, intermingled with +single irregular meshes (fig. 8). Bars of the network smooth, its nodal +points solid, not pierced. + +_Dimensions._--Diameter of the spherical shell 1.5 to 2.5, length of the +bars 0.1 to 0.2, breadth 0.002 to 0.005. + +_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Indian, Pacific, +surface. + + +2. _Sagena pertusa_, n. sp. + +Network subregular, with nearly equal triangular meshes. Bars of the +network smooth, its nodal points pierced by a circular hole. + +_Dimensions._--Diameter of the shell 1.2 to 1.8, length of the bars 0.2 to +0.25, breadth 0.003. + +_Habitat._--Central Pacific, Stations 270 to 274, surface. + + +3. _Sagena triangula_, n. sp. + +Network very regular, with equilateral triangular meshes. Bars of the +network spinulate, like those of _Sagoplegma spinulosa_. (Pl. 108, fig. +14), its nodal points solid, not pierced. + +_Dimensions._--Diameter of the shell 2.2, length of the bars 0.25, breadth +0.004. + +_Habitat._--South Atlantic, Station 325, surface. + + +4. _Sagena crucifera_, n. sp. + +Network more or less irregular, with unequal triangular meshes. Bars of the +network studded with scattered, rectangular, minute crosses, arising +perpendicularly, each cross composed of four small equal bars. Nodal points +partly solid, partly pierced by a hole. Network very similar to that of +_Dictyosoma trigonizon_, figured in my Monograph, Taf. xxvi. figs. 4, 5. + +_Dimensions._--Diameter of the shell 1.5, length of the bars 0.1 to 0.2, +breadth 0.003. + +_Habitat._--Mediterranean, Atlantic, Canary Islands, Station 353, surface. + + + +Genus 676. _Sagosphaera_,[295] n. gen. + +_Definition._--#Sagosphaerida# with a delicate spherical shell, the thin +wall of which is composed of a simple lattice-plate, and bears on its nodal +points radial spines. + +The genus _Sagosphaera_ differs from the preceding _Sagena_, its ancestral +form, in the development of radial spines on the nodal points of the simple +delicate lattice-sphere. It exhibits therefore the same relation to the +latter as _Aulosphaera_ bears to _Aularia_. {1607}The regular or subregular +triangular meshes of the lattice-sphere are separated in _Sagosphaera_ by +solid, very thin threads, in the similar _Aulosphaera_, however, by thicker +hollow tubes. The genus _Sagosphaera_ may be divided into two +subgenera:--_Sagosphaerella_ with a single radial spine at each nodal point +of the network, and _Sagosphaeroma_ with a bunch of two to four or more +divergent radial spines. + + +1. _Sagosphaera trigonilla_, n. sp. + +Radial spines simple, straight, smooth, about as long as the smooth bars of +the network, a single one at each nodal point. Meshes very regular, of +equal size, equilateral triangular. (Similar to the common _Aulosphaera +trigonopa_.) + +_Dimensions._--Diameter of the sphere 1.2 to 1.8, length of the bars 0.1 to +0.2, breadth 0.002 to 0.006. + +_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Pacific, surface. + + +2. _Sagosphaera penicilla_, n. sp. (Pl. 108, fig. 10). + +Radial spines straight, stout, a single one at each nodal point, twice as +thick, but of the same length as the smooth bars of the network, armed at +the distal end with a brush of numerous thin radial bristles. (Very similar +to _Sagenoscena penicillata_, but without pyramidal elevations on the +surface of the sphere.) + +_Dimensions._--Diameter of the sphere 1.0 to 1.5, length of the bars 0.1 to +0.15, breadth 0.002 to 0.004. + +_Habitat._--Antarctic Ocean, Station 154, surface. + + +3. _Sagosphaera verticilla_, n. sp. + +Radial spines slender, slightly curved, a single one at each nodal point, +armed with three to five cruciate verticils, each of which is composed of +four crossed lateral branches with spinulate terminal knobs (similar to +_Sagmidium crucicorne_, Pl. 108, fig. 9), but with a spherical shell, +having a simply latticed, and not a spongy wall. + +_Dimensions._--Diameter of the sphere 2.0 to 2.5, length of the bars 0.1 to +0.2, breadth 0.002. + +_Habitat._--North Pacific, Station 256, surface + + +4. _Sagosphaera furcilla_, n. sp. (Pl. 108, figs. 11, 11_a_). + +Radial spines short, spinulate, with a spiny terminal knob (fig. 11_a_), +two or three arising from each nodal point of the network in divergent +directions, only one-third or one-fourth as long as its smooth bars. Meshes +more or less irregular, triangular. + +_Dimensions._--Diameter of the sphere 2.2, length of the bars 0.2 to 0.3, +breadth 0.004. + +_Habitat._--South Pacific, Station 293, depth 2025 fathoms. + + +{1608}5. _Sagosphaera coronilla_, n. sp. + +Radial spines slender, smooth, three to six arising from each nodal point +of the network in divergent directions, about as long as its smooth bars, +crowned at the distal end with a bunch of twenty to thirty radial terminal +branches, and provided with a spinulate knob at the distal end (similar to +_Sagenoscena stellata_, Pl. 108, fig. 3). + +_Dimensions._--Diameter of the sphere 3.0, length of the bars 0.1 to 0.2, +breadth 0.002. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +Genus 677. _Sagoscena_,[296] n. gen. + +_Definition._--#Sagosphaerida# with a delicate spherical shell, the thin +wall of which is composed of a simple lattice-plate and covered with +numerous pyramidal elevations; each pyramid bears on its top one or more +radial spines, but has no axial rod in its radial axis. + +The genus _Sagoscena_, and the following closely allied _Sagenoscena_ (both +very common and widely distributed), exhibit a peculiar and very remarkable +structure of the delicate lattice-shell, similar to that which _Auloscena_ +represents among the Aulosphaerida. The surface of the simple spherical +lattice-shell is covered with numerous pyramidal or tent-shaped elevations. +These elegant and delicate pyramids are, however, in _Sagoscena_ usually +not so regular as in the similar _Auloscena_; the edges of the pyramids are +in the latter hollow cylindrical tubes, in the former thin solid threads. +The top of each pyramid usually bears a bunch of apical spines. + + +1. _Sagoscena castra_, n. sp. (Pl. 108, fig. 1). + +Pyramids subregular, of equal size and similar form, usually three-sided, +crowned at the top with three divergent apical spines, which alternate with +the three edges of the pyramids and bear a small spinulate terminal knob. +(Some four-sided and single five-sided pyramids are often intermingled with +the three-sided.) + +_Dimensions._--Diameter of the sphere 1.7 to 2.3, length of the bars 0.2 to +0.25, breadth 0.008. + +_Habitat._--South-Eastern Pacific, Stations 295, 296, surface. + + +2. _Sagoscena tentorium_, n. sp. (Pl. 108, fig. 6). + +Pyramids subregular, of equal size and similar form, usually four-sided, +crowned at the top with three divergent apical spines, which are trifurcate +at the distal end. (Some three-sided and five-sided pyramids are often +intermingled with the four-sided.) + +_Dimensions._--Diameter of the sphere 2.2, length of the bars 0.2 to 0.25, +breadth 0.005. + +_Habitat._--South Pacific, Station 291, surface. + + +{1609}3. _Sagoscena praetorium_, n. sp. (Pl. 108, fig. 7). + +Pyramids subregular, of equal size and similar form, usually four-sided, +crowned at the distal top with three or four divergent apical spines, which +bear some irregular verticils of lateral and terminal branches. (Some +five-sided and some six-sided pyramids are often intermingled with the +four-sided.) + +_Dimensions._--Diameter of the sphere 2.6, length of the bars 0.3, breadth +0.006. + +_Habitat._--Central Pacific, Stations 271 to 274, surface. + + +4. _Sagoscena pellorium_, n. sp. (Pl. 108, fig. 5). + +Pyramids subregular, of equal size and similar form, usually five-sided or +six-sided, crowned at the distal end with three to six divergent apical +spines, which bear an irregularly spinulate terminal knob. (The size and +form of the apical spines is here very variable, as well as the number of +the edges of the pyramids, which varies between three and six.) + +_Dimensions._--Diameter of the sphere 3.2, length of the bars 0.15 to 0.25, +breadth 0.008. + +_Habitat._--Antarctic Ocean, Station 156, surface. + + +5. _Sagoscena cruciarium_, n. sp. + +Pyramids subregular, usually six-sided (intermingled with single five-sided +and seven-sided or eight-sided forms), crowned at the distal top with three +divergent, slender, apical spines, each of which bears three to six regular +cruciate verticils; the four crossed lateral branches of each verticil +bearing a spinulate terminal knob. (Similar to _Sagoplegma scenophora_, Pl. +108, fig. 13.) + +_Dimensions._--Diameter of the shell 2.5, length of the bars 0.2 to 0.3, +breadth 0.004. + +_Habitat._--North Pacific, Stations 240 to 244, surface. + + +6. _Sagoscena debilis_, n. sp. + +Pyramids more or less irregular, with four, five, or six sides, of somewhat +different form and unequal size; crowned at the top with one, two, or three +slender apical spines, of variable length. These spines as well as the bars +of the network bear scattered cruciate verticils, each usually composed of +four crossed, small, lateral branches. + +_Dimensions._--Diameter of the shell 2 to 3.0, length of the bars 0.1 to +0.15, breadth 0.003. + +_Habitat._--Central Pacific, Stations 263 to 274, surface. + + +7. _Sagoscena gracilis_, Haeckel. + + _Aulosphaera gracilis_, R. Hertwig, 1879, Organism. d. Radiol., p. 91, + Taf. ix. fig. 4. + +Pyramids more or less irregular, with five, six, or seven sides, often of +somewhat different form and unequal size; crowned at the top with a single +radial spine, which has the same size as the {1610}bars of the network, and +bears in its distal half four cruciate verticils, each composed of four +crossed and curved horizontal branches. + +_Dimensions._--Diameter of the sphere 1 to 2, length of the bars 0.08 to +0.09, breadth 0.002. + +_Habitat._--Mediterranean (Messina), surface. + + +8. _Sagoscena fragilis_, n. sp. + +Pyramids very irregular, with four to eight sides, of different form and +unequal size; crowned at the top with a single, slender, radial spine, of +the same thickness as the slender bars of the network; the latter as well +as the former are smooth, without lateral branches. + +_Dimensions._--Diameter of the sphere 1.0 to 2.0, length of the bars 0.1 to +0.2, breadth 0.001 to 0.002. + +_Habitat._--Cosmopolitan; Atlantic, Pacific, surface. + + + +Genus 678. _Sagenoscena_,[297] n. gen. + +_Definition._--#Sagosphaerida# with a delicate spherical shell, the thin +wall of which is composed of a simple lattice-plate and covered with +numerous pyramidal elevations; each pyramid bears on its top one or more +radial spines, and has an internal axial rod in its radial axis. + +The genus _Sagenoscena_ differs from the preceding closely allied +_Sagoscena_ in the possession of an internal radial axial rod, which arises +in the centre of the base of each pyramid, and is prolonged usually over +its apex into a free, radial, apical spine. The distal end of the latter is +usually armed with a bunch of terminal teeth or bristles. In the similar +_Sagoscena_ the internal cavity of the pyramids is simple, without axial +rod. + + +1. _Sagenoscena stellata_, n. sp. (Pl. 108, fig. 3). + +Pyramids rather regular, usually six-sided (intermingled with single +five-sided and four-sided forms); their axial rod and its prolongation, the +radial apical spine, three to four times as thick as the slender edges of +the pyramid. The distal end of the apical spine bears an elegant star of +numerous radially divergent terminal branches, each of which is armed with +a spinulate terminal knob. + +_Dimensions._--Diameter of the sphere 3.5 to 4.0, length of the net bars +0.3, breadth 0.003; length of the radial spines 0.2, breadth 0.012. + +_Habitat._--South Atlantic, Station 318, depth 2040 fathoms. + + +2. _Sagenoscena ornata_, n. sp. (Pl. 108, fig. 4). + +Pyramids rather regular, usually six-sided (intermingled with single +five-sided and seven-sided forms); their axial rod and apical spine +spindle-shaped, two to four times as thick as the smooth bars {1611}of the +network. The distal end of the radial spines bears an elegant, foliate, +terminal knob, composed of four to six vertical pinnate leaves, lying in +crossed meridional planes. + +_Dimensions._--Diameter of the sphere 2 to 3, length of the rods 0.1 to +0.2, breadth 0.003 to 0.01. + +_Habitat._--Antarctic Ocean, Station 156, depth 1975 fathoms. + + +3. _Sagenoscena penicillata_, n. sp. (Pl. 108, fig. 10). + +Pyramids rather regular, usually six-sided (intermingled with single +five-sided, seven-sided, and eight-sided forms); their axial rod and apical +spine spindle-shaped, thicker than the smooth bars of the network. The +distal end of the radial spines is penicillate and bears a brush of +bristle-shaped, radial, terminal spinules (compare _Sagosphaera penicilla_, +p. 1607). + +_Dimensions._--Diameter of the sphere 1 to 1.5, length of the bars 0.1 to +0.15, breadth 0.004 to 0.005. + +_Habitat._--Antarctic Ocean, Station 157, depth 1950 fathoms. + + +4. _Sagenoscena coronata_, n. sp. + +Pyramids rather regular, usually four-sided (intermingled with single +five-sided and six-sided forms); their axial rod and apical spines +cylindrical, scarcely thicker than the smooth bars of the network. The +distal end of the radial spines bears a corona of twenty to thirty curved +terminal branches, which form a regular circle, and are armed with a +spinulate terminal knob. + +_Dimensions._--Diameter of the sphere 2 to 3, length of the bars 0.12 to +0.18, breadth 0.004 to 0.008. + +_Habitat._--North Pacific, Station 256, surface. + + +5. _Sagenoscena spathillata_, n. sp. + +Pyramids more or less irregular, of different sizes and various forms, each +composed of four to eight convergent rods and a central axial rod. The +latter is prolonged into a free apical spine, which bears at the distal end +a spathilla of eight to twelve recurved teeth, and often beyond it a second +similar verticil. + +_Dimensions._--Diameter of the sphere 4.0, length of the bars 0.1 to 0.2, +breadth 0.002. + +_Habitat._--Arctic Ocean, Greenland (Olrik). + + +6. _Sagenoscena cruciata_, n. sp. + +Pyramids very irregular, of different sizes and various forms, each +composed of six to nine convergent rods and a central axial rod. The latter +is prolonged into a free apical spine, which bears three to five cruciate +verticils, each composed of four perpendicularly crossed lateral branches +which bear at the distal end a spinulate knob (similar to _Sagmidium +crucicorne_, Pl. 108, fig. 9). + +_Dimensions._--Diameter of the sphere 1.0 to 1.2, length of the bars 0.06 +to 0.09, breadth 0.001. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + + +{1612}Subfamily 2. SAGMARIDA, Haeckel. + +_Definition._--#Sagosphaerida# with a spongy spherical shell, the thickened +wall of which is composed of a loose spongy framework. + + + +Genus 679. _Sagmarium_,[298] n. gen. + +_Definition._--#Sagosphaerida# with a spongy spherical shell, the thickened +wall of which is composed of a loose spongy framework, and exhibits a +smooth surface, without radial spines and pyramidal elevations. + +The genus _Sagmarium_, and the following two genera of Sagosphaerida, +represent together the subfamily Sagmarida, differing from the preceding +Sagenida in the spongy structure of the shell-wall. Whilst in the latter +the thin wall of the delicate spherical shell is composed of a simple +lattice-plate with triangular meshes, in the former numerous branches +diverge from the nodal points of these meshes, and produce by union an +irregular and loose spongy framework. The surface of this spongy hollow +sphere (similar to _Plegmosphaera_) is in _Sagmarium_ smooth. + + +1. _Sagmarium spongodictyum_, n. sp. (Pl. 108, fig. 2). + +Spongy wall of the hollow sphere about half as thick as the radius of its +cavity. Bars of the spongy framework very thin and fragile, smooth, without +thorns. + +_Dimensions._--Diameter of the sphere 2.0 to 2.4; length of the bars 0.1 to +0.2, breadth 0.001. + +_Habitat._--South Atlantic, Station 333, surface. + + +2. _Sagmarium plegmosphaerium_, n. sp. (Pl. 108, fig. 14). + +Spongy wall of the hollow sphere about one-fourth as thick as the radius of +its cavity. Bars of the spongy framework rather stout, studded with +numerous small spines, which arise perpendicularly from their surface. + +_Dimensions._--Diameter of the sphere 1.2 to 1.5, length of the bars 0.1 to +0.16, breadth 0.004. + +_Habitat._--Tropical Atlantic, Station 347, surface. + + +3. _Sagmarium trigonizon_, Haeckel. + + _Dictyosoma trigonizon_, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. + Wiss. Berlin, p. 841. + + _Spongodictyon trigonizon_, Haeckel, 1863, Monogr. d. Radiol., p. 459, + Taf. xxvi. figs. 4, 5. + +Bars of the spongy framework thin, irregularly curved, bearing scattered +small crosses, which are composed of four small rods arising +perpendicularly from the bars. Nodal points of the {1613}framework partly +pierced by a hole. The peculiar network of a complete specimen, observed by +me at Portofino in 1880, was so similar to that of _Spongodictyon +trigonizon_, described above (p. 91), and figured in 1862 in my Monograph, +that I am doubtful if the two forms are not identical, the two medullary +shells of the latter being accidentally entangled in the framework. +(Compare p. 1602.) + +_Dimensions._--Diameter of the sphere 1.1 to 1.5, length of the bars 0.1 to +0.2, breadth 0.002. + +_Habitat._--Mediterranean (Messina, Portofino), surface. + + + +Genus 680. _Sagmidium_,[299] n. gen. + +_Definition._--Sagosphaerida with a spongy spherical shell, the thickened +wall of which is composed of a loose spongy framework, and bears on the +nodal points of its surface radial spines. + +The genus _Sagmidium_ differs from the preceding _Sagmarium_ in the +development of radial spines on the surface of the spongy hollow sphere. It +bears therefore the same relation to the latter as _Sagosphaera_ does to +_Sagena_, and may be derived either from _Sagmarium_ by the formation of +radial spines, or from _Sagosphaera_ by development of the spongy envelope. + + +1. _Sagmidium unicorne_, n. sp. + +Radial spines simple, straight, smooth, a single one at each nodal point of +the surface of the spongy sphere, bearing on its distal end a spinulate +knob, or a bunch of numerous radial bristles. (Similar to _Sagenoscena +penicillata_, Pl. 108, fig. 10.) Bars of the spongy framework smooth. + +_Dimensions._--Diameter of the sphere 3.0 to 3.5, length of the bars 0.15 +to 0.2, breadth 0.003 to 0.006. + +_Habitat._--Antarctic Ocean, Station 256, surface. + + +2. _Sagmidium tricorne_, n. sp. + +Radial spines simple, smooth, usually three divergent united at each nodal +point of the surface (sometimes two or four instead of three). Each spine +bears on its distal end three short divergent conical teeth. (Similar to +the terminal teeth of _Sagoscena tentorium_, Pl. 108, fig. 6.) Bars of the +spongy framework smooth. + +_Dimensions._--Diameter of the sphere 1.6 to 2.4, length of the bars 0.06 +to 0.09, breadth 0.001 to 0.002. + +_Habitat._--Central Pacific, Stations 263 to 268, surface. + + +3. _Sagmidium crucicorne_, n. sp. (Pl. 108, fig. 9). + +Radial spines slender, verticillate, three or four divergent arising from +each nodal point of the surface. Each spine bears three to six cruciate +verticils of lateral branches; each verticil being {1614}composed of four +crossed small branches with a spinulate terminal knob. Bars of the spongy +framework partly covered with similar verticils. + +_Dimensions._--Diameter of the sphere 2.0 to 3.0, length of the bars 0.2 to +0.3, breadth 0.002 to 0.003. + +_Habitat._--North Pacific, Stations 240 to 244, surface. + + +4. _Sagmidium quadricorne_, n. sp. (Pl. 108, fig. 12). + +Radial spines stout, smooth, cylindrical, usually four divergent arising +from each nodal point of the surface (sometimes three, five, or six, +instead of four). Each spine bears on its distal end a club-shaped stellate +knob. Bars of the spongy framework smooth. + +_Dimensions._--Diameter of the sphere 4.5, length of the bars 0.2 to 0.3, +breadth 0.003 to 0.005. + +_Habitat._--South Pacific, Station 293, depth 2025 fathoms. + + +5. _Sagmidium multicorne_, n. sp. + +Radial spines slender, more or less curved, verticillate, in variable +number (three to six) divergent, arising from the nodal points of the +surface. The spines as well as the bars of the spongy framework are partly +simple, partly covered with irregularly scattered cruciate verticils, very +similar to those of _Sagmarium trigonizon_ (or _Dictyosoma trigonizon_), +figured in my Monograph, pl. xxvi. figs. 4, 5. + +_Dimensions._--Diameter of the sphere 5.0, length of the bars 0.2 to 0.3, +breadth 0.003. + +_Habitat._--Indian Ocean, Cocos Islands (Rabbe), surface. + + + +Genus 681. _Sagoplegma_,[300] n. gen. + +_Definition._--#Sagosphaerida# with a spongy spherical shell, the thickened +wall of which is composed of a loose spongy framework, and bears on its +surface numerous pyramidal elevations. + +The genus _Sagoplegma_ differs from _Sagmarium_, its ancestral form, in the +development of pyramidal or tent-shaped elevations on the surface of the +spongy hollow sphere. It exhibits, therefore, the same relation to the +latter as the similar _Sagoscena_ bears to _Sagena_. The wall of the +spherical shell is in the two latter genera a thin simple lattice-plate, in +the former a thickened spongy framework. + + +1. _Sagoplegma pyramidophora_, n. sp. + +Pyramids on the surface of the spongy sphere subregular, mostly +tetrahedral, of nearly equal size and similar form. The three edges of each +pyramid are prolonged over its top into three {1615}short, divergent, +apical spines which are forked at the distal end. (Very similar to +_Sagoscena castra_ and _Sagoscena tentorium_, Pl. 108, figs. 1, 6, probably +derived from them, but differing in the spongy structure of the thickened +shell-wall, which is half as thick as the radius of its cavity.) + +_Dimensions._--Diameter of the sphere 2.0 to 2.5, length of the bars 0.15 +to 0.2, breadth 0.002. + +_Habitat._--North Pacific, Stations 231 to 239, surface. + + +2. _Sagoplegma scenophora_ n. sp. (Pl. 108, fig. 13). + +Pyramids on the surface of the spongy sphere irregular, with three to six +sides, unequal in size and different in form. The edges of each pyramid are +prolonged over its top into three to six divergent apical spines, which +bear three to six cruciate verticils, each composed of four small, crossed, +lateral branches, armed with a spinulate knob at the distal end. + +_Dimensions._--Diameter of the sphere 3.0 to 3.5, length of the bars 0.25 +to 0.35, breadth 0.003. + +_Habitat._--North Pacific, Stations 252, 253, surface. + + + +Family LXXVI. #AULOSPHAERIDA#, Haeckel (Pls. 109-111). + + _Aulosphaerida_, Haeckel, 1862, Monogr. d. Radiol., p. 357. + +_Definition._--PHAEODARIA with a large spherical or subspherical (rarely +spindle-shaped) articulated shell, which is composed of hollow tangential +tubes. Nodal points of the loose network stellate, with a nodal cavity and +astral septa. Meshes either triangular or polygonal. Hollow radial spines +arise usually at the nodal points of the surface. No peculiar mouth in the +shell. Central capsule tripylean, placed in the centre of the shell. + +The family #Aulosphaerida# comprises a great number of splendid and widely +distributed PHAEODARIA, which have a special interest on account of the +peculiarly complicated structure of their large lattice-shell, of the +extraordinary beauty of their form and of their remarkable relations to the +other PHAEODARIA. They differ from all the other Radiolaria in the peculiar +articulate composition of the spherical skeleton of hollow tangential +tubes, which are connected (and at the same time separated) by sutural or +astral septa and filled up by jelly. The same peculiar structure recurs +only in the closely allied Cannosphaerida, which, however, differ in the +possession of a second internal concentric shell, connected with the outer +by radial beams. The similar Sagosphaerida, which exhibit corresponding +forms in various genera, differ from the Aulosphaerida in the simpler +structure of the delicate lattice-sphere, which is composed of very thin +solid threads of silica, without astral septa. The Orosphaerida, finally, +also nearly related to the preceding families, differ from them in the +coarse structure of the lattice-sphere, which is composed of very thick +tangential, concentrically stratified rods, with an internal axial canal, +but without astral septa at the nodal points. + +{1616}One genus only, and two species, of Aulosphaerida have been hitherto +known, having been discovered by me in 1859 at Messina, and described in my +Monograph in 1862 as _Aulosphaera trigonopa_ and _Aulosphaera +elegantissima_ (_loc. cit._, p. 357, Taf. x. figs. 4, 5; Taf. ix. figs. 5, +6). The characteristic structure of their central capsule, as true +TRIPYLEA, was afterwards, in 1879, described more accurately by Richard +Hertwig (Organism. d. Radiol., p. 90, Taf. x. figs. 2, 8, 14). The rich +collection of the Challenger has demonstrated that the Aulosphaerida belong +to the most common and most widely distributed PHAEODARIA; many of them are +distinguished by the admirable elegance and astonishing regularity of their +large and delicate shell. Nine genera and fifty-six species of this great +family are described in the following pages, which, however, may represent +only a small part of the numerous forms which are found on the surface as +well as in different depths of all oceans and in all zones. + +The shell is in the great majority of Aulosphaerida a regular sphere or an +endospherical polyhedron. Two genera only, both rather rare, exhibit a +different monaxonial form, one vertical main axis being developed either +more or less than all the other ones of the sphere:--_Aulatractus_ is +spindle-shaped or ellipsoidal, with prolonged main axis; _Aulophacus_ is +lenticular or discoidal, with shortened main axis. The former may be +compared to the #Prunoidea#, the latter to the #Discoidea#, in opposition +to the common regular #Sphaeroidea#. The size of the lattice-shell is very +considerable in all Aulosphaerida, its diameter varying usually between 1 +and 3 mm., often it amounts to 4 or 5 mm.; very rarely the diameter is more +than 5 or less than 1 mm. The largest form observed is the spindle-shaped +_Aulatractus_, in which the vertical prolonged main axis attains 6 to 10 +mm., the horizontal equatorial axis 3 to 5 mm. + +The network of the lattice-shell exhibits in the Aulosphaerida two +different types, according to which we distinguish two different +subfamilies: Aularida and Aulonida; the former are much more common and +richer in remarkable forms than the latter. The meshes of the network are +in the Aularida constantly triangular, regular or subregular, and very +similar to those of the Sagosphaerida; at each nodal point six tangential +tubes are usually united, so that the network may be regarded also as +composed of regular hexagonal meshes, each of which is divided into six +smaller triangular meshes (Pl. 109, figs. 1, 3, 5). The second subfamily, +the Aulonida, are much rarer than the former, and are distinguished by the +polygonal meshes of the network; these are usually more or less irregular, +pentagonal and hexagonal intermingled, more rarely tetragonal, heptagonal, +or octagonal; usually three or four, rarely five or more tangential tubes +are united at each nodal point (Pl. 111, figs. 1, 3). The size of the +meshes is very considerable, and agrees with that of the Sagosphaerida; +their diameter being usually between 0.1 and 0.3, rarely less or more. + +The hollow tubes which compose the loose network are usually cylindrical, +straight or slightly curved, smooth (Pl. 111, fig. 2), more rarely somewhat +spinulate (Pl. 109, {1617}fig. 5). Their length is usually between 0.1 and +0.2 mm., rarely less than 0.08, or more than 0.24 mm.; their diameter +usually between 0.003 to 0.005, sometimes only 0.002 or less, at other +times 0.006 or more. In several species the tangential tubes are thinner in +the middle part, and thickened towards the two ends (Pl. 109, figs. 3, 4). +Each tube consists of a thin cylindrical wall of silex, and of a jelly-mass +filling up its cavity; in its axis runs a very thin, straight or slightly +curved thread of silica, the axial filament. + +The arrangement of the tangential tubes, which originally, in the simplest +Aulosphaerida, lie tangentially in the spherical face of a simple +lattice-sphere, exhibits various secondary modifications, leading to +various interesting generic forms. Two genera only, _Aularia_ (with +triangular meshes, Pl. 111, fig. 2) and _Aulonia_ (with polygonal meshes, +Pl. 111, fig. 1) possess a smooth, perfectly simple lattice-sphere, and may +therefore be regarded as the ancestral genera of the two subfamilies. Two +other corresponding genera, the common _Aulosphaera_ (Pl. 109) and the +rarer _Aulastrum_ (Pl. 111, fig. 3), differ from the former in the +development of radial spines at the nodal points of the simple +lattice-sphere. _Aulophacus_ may be developed from _Aulosphaera_ by +shortening, _Aulatractus_, however, by prolongation of the vertical main +axis (Pl. 111, figs. 6, 7). In two genera, _Auloplegma_ and _Aulodictyum_, +the latticed wall of the spherical shell becomes thickened and spongy, an +irregular framework being formed by tubes connected in different directions +(Pl. 111, fig. 8). The most remarkable and the most elegant form, however, +of the whole family is represented by _Auloscena_ (Pl. 110). The entire +surface of the spherical lattice-shell is here covered with numerous +regular or subregular pyramids, or tent-shaped elevations. Usually each +pyramid is six-sided, and surrounded by six other six-sided pyramids, their +bases being separated by six triangular meshes, which lie in the spherical +face. A similar elegant form is developed among the Sagosphaerida in the +genera _Sagoscena_, _Sagenoscena_ and _Sagoplegma_ (Pl. 108, fig. 1). The +structure of _Auloscena_, however, is usually more regular, and in the top +of each pyramid a radial tube arises. + +The junction of the cylindrical tubes at the nodal points of the network is +very remarkable. _Aularia_, the simplest form of the family, exhibits at +each nodal point the union of six tangential tubes (Pl. 111, fig. 2); their +ends are so pointed and truncated that they are connected in the form of a +regular six-radiate star; the conical end of each tube is separated from, +and at the same time closely connected with, the adjacent conical ends of +the two neighbouring tubes by a thin septum, the astral or sutural septum. +The six astral septa compose together a six-radiate star, and in the centre +of this star the six axial filaments of the tubes are united. Their central +union is surrounded by a small, double-contoured circle, and this circle +seems to be the perimeter of a small and flat cavity on the inside of the +star, which we call shortly the "nodal cavity" ("die kleine Vertiefung" +according to Hertwig, _loc. cit._, p. 90). The nodal cavity of _Aularia_ +probably possesses a central opening on its inside and six small +surrounding pores, which {1618}lead into the six connected tangential +tubes. In _Aulosphaera_ and _Auloscena_, where a radial spine arises at +each nodal point, its axial filament arises from the centre of the star, +and is usually prolonged on the inside into a free centripetal beam (Pl. +109, figs. 6, 7; Pl. 110, figs. 4, 6). This centripetal beam is a slender, +very thin, conical tube (often with a six-sided pyramidal base) and perhaps +of great morphological interest as a rudiment, being homologous to the +hollow radial beams which connect the two concentric spheres of the +Cannosphaerida. Possibly the Aulosphaerida have been derived from the +latter by loss of the inner shell and reduction of the radial beams; the +centripetal beams which are found in many (but not in all) Aulosphaerida, +may be the last remnant of those radial beams. They contain also an axial +filament, as a direct internal prolongation of that of the external radial +spine. The axial filaments of the radial spines are usually connected with +their thin wall by a variable number of scattered transverse threads, or +sometimes even by thin transverse septa (Pl. 110, figs. 4-7, &c.). This +structure corresponds to the similar axial filaments and their thin +filiform transverse branches which we have found in other PHAEODARIA, +_e.g._, in the Tuscarorida and Circoporida. + +The Aulonida (with polygonal meshes) exhibit in general the same structure +as the Aularida (with triangular meshes). But whilst in the latter usually +six tangential tubes are united at each nodal point, in the former only +three or four tubes become united. Therefore also the number of the small +sutural partitions or astral septa, which radiate from the central openings +of the nodal cavity, is six in the latter, three or four in the former. +Correspondingly three or four small pores lead from the nodal cavity into +the surrounding tangential tubes. + +The true nature of the nodal points, and the intimate structure of the +different parts here united, is a matter which it is very difficult to +explain. It is a certain fact, well established by hundreds of +observations, that in the complete and well-preserved skeletons which are +perfectly purified by fire, or by hot mineral acids, and afterwards dried, +all the tubes of the skeleton, the tangential as well as the radial +cylinders, become filled up by air. Each tube contains usually one large +cylindrical air-bubble, with two hemispherical ends. But the air-bubbles of +the neighbouring tubes are completely separated one from another by the +thin astral or sutural septa, and the air-bubble of the radial tubes is +also separated from the former. The central cavity of each nodal point is +therefore surrounded in the Aularida by six, in the Aulonida by three or +four separate cylinders of air. This fact seems to be explained only on the +supposition that each single tube has two terminal pores or fissures, which +open into the two nodal cavities on its two ends. The radial tubes must +also possess at least one small opening, probably on their base, and +probably they have another on their distal apex. In no other way can it be +explained, that in all complete, well-preserved and purified skeletons, +each single tube constantly becomes easily filled by an air-bubble after +drying. + +In the living Aulosphaerida the cavities of all tubes are filled up by a +jelly-substance, {1619}which may be stained by carmine and is probably +identical with the jelly of the calymma. The latter is probably in direct +connection with the former by the central pore of the nodal cavity, which +is placed on its inside and surrounded by the astral septa; these separate +the tangential tubes, radiating from one nodal point, completely, and are +thin and simple, but very solid lamellae of silica. Therefore the nodal +stars of broken shells usually remain united, whilst the single radiating +tubes composing them are broken off (Pl. 110, figs. 3, 8, 10). But it +happens only rarely (and only in certain individual species) that complete +single tubes separate; usually the fragments of the connected neighbouring +tubes remain on their ends. The two small terminal openings of each +tangential tube, which lead from its cavity into the nodal cavity, and are +surrounded on each end by the truncated ends of two neighbouring astral +septa, are very difficult to observe (Pl. 110, figs. 8-10). + +The wonderful elegance and the high complication of these regular skeletons +of the Aulosphaerida, produced by a single cell, becomes increased by the +graceful and manifold appendages and apophyses which are usually developed +on the radial tubes. In only a few species these are simple, as in the +common and cosmopolitan _Aulosphaera trigonopa_. Usually lateral or +terminal appendages are developed in great variety, a selection of which is +figured in Pls. 109-111. The lateral branches are either irregularly +scattered spines (Pl. 110, figs. 3-7) or regular verticils of cruciate or +radiate spines; each verticil is usually composed of four perpendicularly +crossed horizontal branches (Pl. 109, figs. 3, 4, 7, 10, &c.), more rarely +of a greater number of radiating transverse branches. + +The terminal appendages of the radial spines exhibit a striking similarity +with those of the Aulacanthida (Pls. 102-105). They are either forks with +two or three divergent branches (Pl. 111, figs. 3, 4), or regular crosses +with four branches opposite in pairs (Pl. 109, figs. 2, 6, 7, 10), or +elegant crowns or verticils, composed of numerous radiating branches (Pl. +110, figs. 1-6). The distal ends of the terminal as well as of the lateral +branches are either simple, pointed, or armed with a spinulate knob, or +with a terminal spathilla. The variety and elegance of these terminal +ornaments, the function of which is that of capturing tentacles, is in the +Aulosphaerida not less admirable than in the Aulacanthida and +Coelodendrida. + +The _central capsule_ of the Aulosphaerida (Pl. 111, fig. 2) was first +figured in my Monograph (1862, Taf. xi. fig. 5) of _Aulosphaera +elegantissima_, as a sphere of 0.2 to 0.3 mm. in diameter. I described +there the large nucleus (of half that size) as a spherical "Binnenblase," +and the numerous pseudopodia which arise from the capsule and radiate +through the meshes of the lattice-shell. But I had not observed at that +time the three typical openings of the capsule, which were first discovered +and accurately described by R. Hertwig (1879, _loc. cit._, p. 94, Taf. x. +figs. 2, 4, 5, 8, 14). The large astropyle with its radiate operculum and +proboscis, and the two smaller lateral parapylae, provided with {1620}a +smaller tubule, have in general the same shape as in the closely allied +Sagosphaerida and Orosphaerida, and agree in their strong development with +that of the Aulacanthida. The collection of the Challenger contains +numerous well-preserved preparations of Aulosphaerida, which were stained +by carmine immediately after being captured, and in which the central +capsule and its nucleus exhibit the same intimate structure already +accurately described by R. Hertwig. The diameter of the capsule is usually +between 0.2 and 0.3, rarely less than 0.15 or more than 0.35 mm., the +nucleus has half that size. The phaeodium has usually about the same volume +(Pl. 109, fig. 1), but seems to be in many Aulosphaerida less developed +than in the other PHAEODARIA. + +_Synopsis of the Genera of Aulosphaerida._ + + ------------------------------------------------------------------------- + I. Subfamily Aularida. + Meshes of the network triangular, regular or subregular. Six + tangential tubes united at each nodal point of the net. + ------------------------------------------------------------------------- + { Without radial tubes, 682. _Aularia_. + Shell spherical, with { + a simple network. { With radial tubes in + { the nodes of the net, 683. _Aulosphaera_. + + { Shell covered with pyramidal + { elevations, the top of + Shell spherical, with { which bears a radial tube, 684. _Auloscena_. + pyramidal elevations { + or with spongy { Shell with spongy framework, + framework. { the surface of which bears + { radial tubes, 685. _Auloplegma_. + + { Shell lenticular, with + Shell not spherical, { shortened main axis and + either lenticular or { radial tubes, 686. _Aulophacus_. + spindle-shaped, with { + simple network. { Shell spindle-shaped, with + { prolonged main axis and + { radial tubes, 687. _Aulatractus_. + ------------------------------------------------------------------------- + II. Subfamily Aulonida. + Meshes of the network polygonal, usually irregular. Three or four + (rarely more) tangential tubes united at each nodal point. + ------------------------------------------------------------------------- + { Without radial tubes, 688. _Aulonia_. + Shell spherical, with { + a simple network. { With radial tubes in the + { nodes of the net, 689. _Aulastrum_. + + Shell spherical, with { Without radial tubes, 690. _Aulodictyum_. + a spongy framework. { + + + +Subfamily 1. AULARIDA, Haeckel. + +_Definition._--Network of the shell with triangular, regular or subregular +meshes; six tangential tubes being united at each nodal point. + + + +{1621}Genus 682. _Aularia_,[301] n. gen. + +_Definition._--#Aulosphaerida# with triangular meshes in the network, the +tangential tubes of which form a simple smooth lattice-sphere. No radial +tubes at the nodal points. + +The genus _Aularia_ is the simplest form of the subfamily Aularida, or of +those Aulosphaerida in which the network of the shell is composed of +regular or subregular triangular meshes; they are the main group of the +family, much more common and far richer in distinct forms than the Aulonida +(or the Aulosphaerida with polygonal meshes). The shell of _Aularia_, the +probable ancestral form of the family, is a simple lattice-sphere with +smooth surface, and differs from the common _Aulosphaera_ in the absence of +radial tubes, arising at the nodal points. + + +1. _Aularia ternaria_, n. sp. (Pl. 111, fig. 2). + +Tangential tubes of the network cylindrical, straight, smooth, of equal +breadth. Triangular meshes of the reticular sphere very regular, +equilateral triangular. This species is the simplest of all Aulosphaerida +and similar to the common _Aulosphaera trigonopa_, but has no radial tubes. + +_Dimensions._--Diameter of the sphere 1.0 to 2.0; tubes 0.1 to 0.15 long, +0.007 to 0.01 broad. + +_Habitat._--Central Pacific, Stations 270 to 274, surface. + + +2. _Aularia tubularia_, n. sp. + +Tangential tubes of the network cylindrical, straight, of equal breadth, +thorny, covered with numerous short bristle-shaped thorns, which are all of +the same length and perpendicular to the tube. + +_Dimensions._--Diameter of the sphere 3.0; tubes 0.15 long, 0.005 broad. + +_Habitat._--South Pacific, Station 291, depth 2250 fathoms. + + +3. _Aularia trigonaria_, n. sp. + +Tangential tubes of the network smooth, very thin in the middle part, +gradually dilated towards both ends, so that the nodal points of the +network are inflated. (Similar to _Aulosphaera sceptrophora_, Pl. 109, fig. +3, but without radial tubes.) + +_Dimensions._--Diameter of the sphere 2.2; tubes 0.1 long, 0.002 broad in +the middle part, 0.01 on both sides. + +_Habitat._--North Pacific, Station 253, depth 3125 fathoms. + + + +{1622}Genus 683. _Aulosphaera_,[302] Haeckel, 1860, Monatsber. d. k. +preuss. Akad. d. Wiss. Berlin, p. 802. + +_Definition._--#Aulosphaerida# with triangular meshes in the network, the +tangential tubes of which form a simple lattice-sphere. Radial tubes arise +at its nodal points. + +The genus _Aulosphaera_, the first observed form of all Aulosphaerida, is +also the most common form of the whole family, the richest in distinct +species, and widely distributed over all oceans, in the tropical as well as +in the temperate and Arctic zones. + +The twenty-one species here enumerated may be only a small part of the +numerous forms, which may be distinguished according to the different forms +of the tubes. One of the two Mediterranean species, which I first described +in my Monograph, is cosmopolitan. The shell is in all species a simple +regular lattice-sphere with triangular meshes; it differs from the +preceding _Aularia_ in the development of radial tubes at the nodal points +of the lattice-work. + + + +Subgenus 1. _Aulosphaerantha_, Haeckel. + +_Definition._--Radial tubes simple, smooth, without terminal teeth and +without lateral branches. + + +1. _Aulosphaera trigonopa_, Haeckel. + + _Aulosphaera trigonopa_, Haeckel, 1862, Monogr. d. Radiol., p. 359, Taf. + x. fig. 4. + +Radial tubes of the spherical shell cylindro-conical, straight, smooth, of +the same length as the tangential tubes of the network, which are also +smooth, straight, cylindrical. + +_Dimensions._--Diameter of the sphere 1.0 to 2.0; tangential tubes 0.1 to +0.2 long, 0.002 to 0.004 broad. + +_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Indian, Pacific, +surface. + + +2. _Aulosphaera flexuosa_, n. sp. + +Radial tubes slenderly conical, smooth, gradually tapering towards the +distal end, more or less irregularly curved, two to three times as long as +the tangential tubes, which are cylindrical, straight and smooth. + +_Dimensions._--Diameter of the sphere 2.2; tangential tubes 0.15 long, +0.006 broad. + +_Habitat._--North Atlantic, Faeroee Channel (Gulf Stream), John Murray, +surface. + + + +{1623}Subgenus 2. _Aulosphaerella_, Haeckel. + +_Definition._--Radial tubes smooth, without lateral branches or spines, but +armed with a verticil of teeth at the distal end. + + +3. _Aulosphaera diodon_, n. sp. + +Radial tubes cylindro-conical, straight, smooth, of the same length as the +smooth, cylindrical, tangential tubes; armed at the distal end with two +divergent terminal teeth, which are slightly curved, pincer-shaped, and +about one-fourth as long as the tube. + +_Dimensions._--Diameter of the sphere 2.5; tangential tubes 0.16 long, +0.003 broad. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +4. _Aulosphaera triodon_, n. sp. (Pl. 109, fig. 8). + +Radial tubes cylindrical, straight, smooth, two to three times as long as +the smooth, cylindrical, tangential tubes; armed at the distal end with +three divergent terminal teeth, which are straight or slightly curved and +about one-third as long as the tube. + +_Dimensions._--Diameter of the sphere 1.2; tangential tubes 0.1 long, 0.01 +broad. + +_Habitat._--North-Eastern Pacific (off Japan), Station 231, surface. + + +5. _Aulosphaera tetrodon_, n. sp. + +Radial tubes slender, cylindrical, straight, smooth, about three times as +long as the smooth, cylindrical, tangential tubes; armed at the distal end +with a regular cross of four terminal teeth, which are directed almost +horizontally, and are slightly recurved (just as in _Aulosphaera +spathillata_, Pl. 109, fig. 7, but longer and without lateral verticils). + +_Dimensions._--Diameter of the sphere 1.6; tangential tubes 0.15 long, +0.005 broad. + +_Habitat._--South Pacific, Station 289, depth 2550 fathoms. + + +6. _Aulosphaera polyodon_, n. sp. + +Radial tubes slender, spindle-shaped, gradually tapering towards the two +ends, smooth, about twice as long as the cylindrical, smooth, tangential +tubes; armed at the distal end with a verticil of twelve to twenty or more +divergent, conical, slightly curved teeth. + +_Dimensions._--Diameter of the sphere 3.3; tangential tubes 0.2 long, 0.01 +broad. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + + +Subgenus 3. _Aulosphaerissa_, Haeckel. + +_Definition._--Radial tubes verticillate, armed with a variable number of +regular verticils of lateral branches. + + +{1624}7. _Aulosphaera verticillata_, n. sp. + +Radial tubes slender, cylindro-conical, straight, tapering towards the +distal end, about as long as the smooth, cylindrical, tangential tubes; +armed with eight to twelve verticils of three curved, simple, lateral +branches. (Very similar to the tubes of _Aulastrum trichoceros_, Pl. 111, +fig. 5_a._) + +_Dimensions._--Diameter of the sphere 1.6; tangential tubes 0.15 long, +0.008 broad. + +_Habitat._--South Pacific, Station 300, surface. + + +8. _Aulosphaera spathillata_, n. sp. (Pl. 109, figs. 7, 7_a_). + +Radial tubes slender, cylindro-conical, straight, tapering towards the +distal end, two to three times as long as the smooth, cylindrical, +tangential tubes; armed with two or three distal alternate verticils, each +of which forms a horizontal cross of four (sometimes three or five) +equidistant branches; their distal ends are on the terminal cross simple +hooks, on the proximal cross spathillae. + +_Dimensions._--Diameter of the sphere 3.2; tangential tubes 0.12 to 0.16 +long, 0.01 broad. + +_Habitat._--South-Eastern Pacific (off Valparaiso), Station 298, depth 2225 +fathoms. + + +9. _Aulosphaera cruciata_, Haeckel (Pl. 109, fig. 10). + + _Aulosphaera elegantissima_, R. Hertwig (_non_ Haeckel), 1879, Organism. + d. Radiol., p. 90, Taf. ix. fig. 1; Taf. x. figs. 2, 4, 5, 8, 14, 15. + + ? _Aulosphaera pourtalesii_, Duncan, 1881, Journ. Roy. Micr. Soc., p. + 175, pl. iii. figs. 1-3. + +Radial tubes slender, cylindro-conical, straight, tapering towards the +distal end, twice as long as the smooth, cylindrical, tangential tubes; +armed with four to eight cruciate equidistant verticils, each of which +forms a regular cross of four equal, horizontal, lateral branches, bearing +at the end a small knob or spathilla. + +_Dimensions._--Diameter of the sphere 1.2 to 1.8; tangential tubes 0.1 to +0.15 long, 0.003 broad. + +_Habitat._--Mediterranean (Messina), North Atlantic (Canary Islands), +Caribbean Sea. + + +10. _Aulosphaera elegantissima_, Haeckel. + + _Aulosphaera elegantissima_, Haeckel, 1862, Monogr. d. Radiol., p. 359, + Taf. x. fig. 5; Taf. xi. figs. 5, 6. + +Radial tubes cylindrical, straight, twice as long as the smooth, +cylindrical, tangential tubes; armed with four to eight equidistant +verticils, each of which is composed of eight to twelve simple, horizontal, +lateral branches. + +_Dimensions._--Diameter of the sphere 1.5 to 2; tangential tubes 0.12 to +0.16 long, 0.004 broad. + +_Habitat._--Mediterranean (Messina), surface. + + +11. _Aulosphaera bisternaria_, n. sp. (Pl. 109, figs. 11, 12). + +Radial tubes cylindrical, straight, about as long as the cylindrical +tangential tubes, smooth or somewhat thorny, armed at the distal end with +two alternate verticils of three branches, which bear {1625}a terminal +spathilla; the proximal branches are twice as long as the distal, and +alternate with them regularly, so that the six branches lie in six +different meridional planes. + +_Dimensions._--Diameter of the sphere 2.5; tangential tubes 0.2 long, 0.01 +broad. + +_Habitat._--Antarctic Ocean, Station 156, surface. + + +12. _Aulosphaera dendrophora_, n. sp. (Pl. 109, figs. 1, 2). + +Radial tubes cylindrical, straight, about as long as the cylindrical, +smooth, tangential tubes, armed in the distal half with three verticils of +four crossed branches; the four proximal branches are three times as long +as the four distal, and twice as long as the four intermediate branches. +All twelve branches bear a terminal spinulate knob, and lie in two +perpendicularly crossed meridian planes. + +_Dimensions._--Diameter of the sphere 2.2 to 2.8; tangential tubes 0.2 +long, 0.01 broad. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +13. _Aulosphaera sceptrophora_, n. sp. (Pl. 109, figs. 3, 4). + +Radial tubes straight, in the proximal half conical, with inflated base; in +the distal half cylindrical, with five or six cruciate verticils, each of +which has four perpendicularly crossed teeth. Tangential tubes half as long +as the radial tubes, in the middle part very thin, thickened towards both +ends. + +_Dimensions._--Diameter of the sphere 1.2; tangential tubes 0.1 long, 0.002 +broad in the middle part, 0.012 on both ends. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +14. _Aulosphaera spathophora_, n. sp. + +Radial tubes slender, cylindrical, more or less curved, about three times +as long as the tangential tubes, in the distal half with eight to twelve +verticils of six to eight lateral branches, which are forked, decrease in +length towards the distal end, and bear on each ramule a terminal +spathilla. Tangential tubes slightly curved and thorny. (Similar to +_Auloplegma perplexum_, Pl. 111, fig. 8_a_, but with a simple +lattice-sphere.) + +_Dimensions._--Diameter of the sphere 2.2; tangential tubes 0.2 long. 0.006 +broad. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + + +Subgenus 4. _Aulosphaeromma_, Haeckel. + +_Definition._--Radial tubes spiny or thorny, with irregular lateral +branches, often with forked distal ends. + + +{1626}15. _Aulosphaera bifurca_, n. sp. + +Radial tubes cylindrical, straight, thorny, twice as long as the smooth, +cylindrical, tangential tubes, forked at the distal end, with two curved, +convergent, thorny, terminal branches. (Similar to _Aulastrum dendroceros_, +Pl. 111, figs. 4_a_-4_c_, but with longer and more spinulate branches.) + +_Dimensions._--Diameter of the sphere 3.2; tangential tubes 0.25 long, 0.01 +broad. + +_Habitat._--North Pacific, Station 239, surface. + + +16. _Aulosphaera trifurca_, n. sp. (Pl. 109, fig. 9). + +Radial tubes cylindrical, straight, thorny, about as long as the smooth, +cylindrical, tangential tubes, forked at the distal end, with three curved, +convergent, terminal branches. + +_Dimensions._--Diameter of the sphere 2.5 to 3.0; tangential tubes 0.2 +long, 0.01 broad. + +_Habitat._--North Pacific, Station 240, surface. + + +17. _Aulosphaera quadrifurca_, n. sp. + +Radial tubes cylindro-conical, straight, about as long as the smooth, +cylindrical, tangential tubes; studded with numerous irregular lateral +branches in the distal half, and armed at the distal end with a cross of +four divergent, forked, terminal branches. + +_Dimensions._--Diameter of the sphere 4.2; tangential tubes 0.2 long, 0.01 +broad. + +_Habitat._--Indian Ocean, Madagascar (Rabbe), surface. + + +18. _Aulosphaera multifurca_, n. sp. + +Radial tubes cylindrical, more or less curved, three to four times as long +as the smooth, often curved, tangential tubes; studded with numerous +forked, irregular, lateral branches, and armed at the distal end with a +verticil of twelve to sixteen divergent, forked, terminal branches. + +_Dimensions._--Diameter of the sphere 1.2; tangential tubes 0.06 long, +0.003 broad. + +_Habitat._--Arctic Ocean, Greenland (Olrik), surface. + + +19. _Aulosphaera coronata_, n. sp. + +Radial tubes spindle-shaped, tapering from the thicker middle part towards +both ends, twice as long as the thorny tangential tubes, studded with +numerous irregular, curved, lateral spines, and bearing at the distal end a +corona of twenty to twenty-five divergent, curved, terminal branches. +(Similar to _Auloscena flammabunda_, Pl. 110, fig. 4.) + +_Dimensions._--Diameter of the sphere 3.0; tangential tubes 0.2 long, 0.08 +broad. + +_Habitat._--Tropical Atlantic, Station 347, surface. + + +{1627}20. _Aulosphaera undulata_, n. sp. (Pl. 109, fig. 6). + +Radial tubes slender, cylindro-conical, undulate, about twice as long as +the spinulate and undulate tangential tubes; studded with numerous short, +perpendicular, lateral branches which are partly simple, partly forked, and +bear small terminal spathillae. The distal end of each radial tube bears +usually a verticil of four to eight similar pediculate spathillae. + +_Dimensions._--Diameter of the sphere 2.4; tangential tubes 0.2 long, 0.005 +broad. + +_Habitat._--North Pacific, Station 252, surface. + + +21. _Aulosphaera spinosa_, n. sp. (Pl. 109, fig. 5). + +Radial tubes and tangential tubes equal in size and similar in form, more +or less curved, slender, cylindrical, densely studded with numerous +irregular spines. + +_Dimensions._--Diameter of the sphere 1.6; tangential tubes 0.1 long, 0.004 +broad. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +Genus 684. _Auloscena_,[303] n. gen. + +_Definition._--#Aulosphaerida# with triangular meshes in the network, the +tangential tubes of which arise in pyramidal groups of six over the surface +of the spherical shell. Radial tubes arise at the tops of the six-sided +pyramids, which cover the whole surface. + +The genus _Auloscena_ differs from the preceding _Aulosphaera_, its +ancestral form, in a very remarkable and elegant character. The tangential +tubes of the network here lie not on a spherical face (as in the latter), +but arise over the surface of the spherical calymma in the form of +numerous, regular, hexagonal pyramids; each pyramid being composed of six +convergent ascending tubes, which are united in a common nodal point; at +the latter arises a radial tube, which usually bears an elegant corona of +radially divergent terminal branches. Therefore the base of each hexagonal +pyramid is in contact at its six corners with the basal corners of six +similar neighbouring pyramids, whilst the neighbouring sides of the bases +are separated by six regular triangular meshes, which lie on the spherical +face. In some species this remarkable and elegant structure is quite +regular, whilst in others it becomes more or less irregular. + + + +Subgenus 1. _Auloscenium_, Haeckel. + +_Definition._--Radial tubes smooth, without lateral branches or spines, +bearing a terminal verticil at the distal end. + + +{1628}1. _Auloscena mirabilis_, n. sp. (Pl. 110, figs. 1, 2). + +Radial tubes cylindrical, straight, smooth, about as long as the smooth +pyramidal tubes (or the convergent tubes which form the edges of the +six-sided pyramids of the network). The distal end of each radial tube +bears an elegant spathillate terminal corona (fig. 2), or a verticil of +fifteen to twenty curved radial branches, the distal end of which is armed +with a spinulate knob. + +_Dimensions._--Diameter of the sphere 2.0 to 3.0; pyramidal tubes 0.16 to +0.24 long, 0.008 broad. + +_Habitat._--Central Pacific, Stations 271 to 274, depth 2350 to 2750 +fathoms. + + +2. _Auloscena spectabilis_, n. sp. (Pl. 110, figs. 8, 9). + +Radial tubes cylindro-conical, straight, smooth, twice as long as the +smooth pyramidal tubes, armed at the distal end with a conical terminal +corona, or a verticil of twelve to sixteen divergent, straight, pointed, +terminal branches. + +_Dimensions._--Diameter of the sphere 4.0 to 5.0; pyramidal tubes 0.25 to +0.3 long, 0.012 broad. + +_Habitat._--Antarctic Ocean, Station 154, surface. + + +3. _Auloscena pyramidalis_, n. sp. + +Radial tubes slender, conical, straight, smooth, of the same length as the +smooth pyramidal tubes, armed at the distal end with a hexagonal terminal +corona, or a verticil of six divergent, straight, pointed, terminal +branches, which correspond to the six sides of a pyramid; the proximal apex +of this terminal pyramid is opposed to the distal apex of the similar basal +pyramid. + +_Dimensions._--Diameter of the sphere 3.0 to 4.0; pyramidal tubes 0.2 to +0.3 long, 0.01 broad. + +_Habitat._--Tropical Atlantic, Stations 347 to 349, surface. + + + +Subgenus 2. _Auloscenidium_, Haeckel. + +_Definition._--Radial tubes thorny, with lateral branches or spines, +usually with a terminal verticil at the distal end. + + +4. _Auloscena tentorium_, n. sp. (Pl. 110, fig. 6). + +Radial tubes spindle-shaped, tapering towards both ends, nearly smooth, of +the same length as the smooth pyramidal tubes. The distal part of the +radial tubes is thorny, and bears a verticil or a corona of twenty to +thirty slender terminal branches, which are about one-third as long as the +tube, sabre-shaped, with concave outer edge and pointed distal end. + +_Dimensions._--Diameter of the sphere 4.0; radial tubes 0.3 to 0.4 long, +0.02 to 0.03 broad. + +_Habitat._--North-Western Pacific (off Japan), Station 231, surface. + + +{1629}5. _Auloscena verticillus_, n. sp. (Pl. 110, figs. 10, 11). + +Radial tubes slender, cylindrical, twice as long as the smooth or somewhat +thorny pyramidal tubes, armed in the distal part with two or three +irregular verticils of three to six perpendicular spines, and on the distal +end with a corona of twelve to eighteen straight, divergent, pointed, +terminal branches, which often arise in pairs. + +_Dimensions._--Diameter of the sphere 3.2; pyramidal tubes 0.15 long, 0.01 +broad. + +_Habitat._--South Atlantic, Station 318, depth 2040 fathoms. + + +6. _Auloscena penicillus_, n. sp. (Pl. 110, fig. 3). + +Radial tubes slender, cylindrical, thorny, one and a half times as long as +the thin and smooth pyramidal tubes, armed in the distal half with densely +crowded perpendicular spines and a terminal corona of numerous (twenty to +thirty or more) bristle-shaped branches, like a brush. + +_Dimensions._--Diameter of the sphere 2.0 to 2.5; radial tubes 0.15 to 0.2 +long, 0.005 to 0.01 broad. + +_Habitat._--Antarctic Ocean, Stations 156, 157, surface. + + +7. _Auloscena flammabunda_, n. sp. (Pl. 110, fig. 4). + +Radial tubes cylindro-conical, twice as long as the thorny pyramidal tubes, +studded with numerous curved spines, and armed with a verticil or corona of +numerous (twenty to thirty or more) undulate, divergent, pointed, terminal +branches. + +_Dimensions._--Diameter of the sphere 3.0; radial tubes 0.3 to 0.4 long, +0.02 to 0.03 broad. + +_Habitat._--North Pacific, Station 252, surface. + + +8. _Auloscena gigantea_, n. sp. (Pl. 110, fig. 7). + +Radial tubes cylindrical, thorny, about as long as the thorny pyramidal +tubes, armed in the distal half with four to eight verticils of short +curved ciliae, and at the distal end with a similar small terminal +verticil. + +_Dimensions._--Diameter of the sphere 5.2; pyramidal tubes 0.2 to 0.3 long, +0.01 broad. + +_Habitat._--Central Pacific, Stations 265 to 268, surface. + + +9. _Auloscena arboretum_, n. sp. + +Radial tubes cylindrical, straight or slightly curved, about the same +length as the smooth pyramidal tubes; armed in the distal half with three +or four verticils, tapering in size towards the distal end; each verticil +is composed of four crossed and curved branches, which bear a terminal +spinulate knob. (This species is very similar to _Aulosphaera dendrophora_, +Pl. 109, fig. 1, and may {1630}be derived from it by elevation of the +hexagonal pyramids, which in the latter lie in the spherical plane). + +_Dimensions._--Diameter of the sphere 4.4; pyramidal tubes 0.25 long, 0.01 +broad. + +_Habitat._--Indian Ocean, Cocos Islands (Rabbe), surface. + + +10. _Auloscena serrata_, n. sp. (Pl. 110, fig. 5). + +Radial tubes spindle-shaped, tapering towards both ends, thorny, twice as +long as the thorny pyramidal tubes; armed at the distal end with an elegant +corona which is composed of twelve to sixteen curved terminal branches. +Each branch bears two opposite series of small recurved teeth and a +terminal spathilla of six to eight larger recurved teeth. + +_Dimensions._--Diameter of the sphere 3.0; pyramidal tubes 0.3 long, 0.012 +broad. + +_Habitat._--South Pacific, Station 298, depth 2225 fathoms. + + + +Genus 685. _Auloplegma_,[304] Haeckel, 1879, Sitzungsb. med.-nat. +Gesellsch. Jena, Dec. 12, p. 6. + +_Definition._--#Aulosphaerida# with triangular meshes in the network, the +tubes of which are connected in different directions, and form the spongy +wall of a spherical shell. Radial tubes arise on the surface at the nodal +points. + +The genus _Auloplegma_, one of the rarest forms of Aulosphaerida, differs +from the preceding genera in the spongy structure of the lattice-sphere, +the thickened wall of which is composed of a loose framework. Numerous +tubes, irregularly disposed in different directions, are connected at the +nodal points of this loose spongy framework, whilst radial tubes arise on +the surface of the latter. _Auloplegma_ exhibits therefore a relation to +_Aulosphaera_, its probable ancestral form, similar to that which +_Plegmosphaera_ does to _Acanthosphaera_ among the #Sphaeroidea#. + + +1. _Auloplegma perplexum_, n. sp. (Pl. 111, figs. 8, 8_a_). + +Radial tubes straight, cylindro-conical, armed with six to eight verticils +of lateral branches, which increase in size towards the base; each verticil +is a cross of four dichotomous delicate ramules, ending with a spinulate +knob. The length of the radial tube is about equal to the radial diameter +of the spongy framework, which forms the thick wall of the spherical shell, +and is composed of smooth and straight cylindrical tubes. + +_Dimensions._--Diameter of the shell 1.5 to 2.0, of its wall 0.3 to 0.4; +length of the radial tubes 0.2 to 0.3, basal breadth 0.015. + +_Habitat._--North Pacific, Station 237, surface. + + +{1631}2. _Auloplegma spongiosum_, n. sp. (Pl. 111, fig. 9). + +Radial tubes slender, straight, cylindro-conical, studded irregularly with +lateral branches, which are short, simple, slightly curved, partly +verticillate in the distal third, and ending with a small spinulate knob. +The length of the radial tubes is about twice as great as the radial +diameter of the spongy framework, which forms the wall of the spherical +shell, and is composed of thorny or verticillate cylindrical tubes. + +_Dimensions._--Diameter of the shell 3.2, of its wall 0.1; length of the +radial tubes 0.24, breadth 0.01. + +_Habitat._--North Pacific, Station 231, surface. + + + +Genus 686. _Aulophacus_,[305] n. gen. + +_Definition._--#Aulosphaerida# with triangular meshes in the network, the +tangential tubes of which form a simple, lenticular, biconvex +lattice-shell, with shortened vertical main axis. Radial tubes arise at its +nodal points. + +The genus _Aulophacus_ differs from the common _Aulosphaera_, its ancestral +form, only in the lenticular compression of the spherical lattice-shell, +the vertical axis of which is considerably shortened. It exhibits therefore +to the latter the same relation as _Cenodiscus_ does to _Cenosphaera_ among +the #Sphaeroidea#. The contrary condition is shown in the following genus +_Aulatractus_, in which the vertical axis is prolonged. In the two species +of _Aulophacus_ observed the radial spines exhibit a remarkable +peculiarity, being longer on the circular periphery of the lens, shorter on +both its faces, and shortest in the vertical main axis. + + +1. _Aulophacus lenticularis_, n. sp. (Pl. 111, fig. 5_a_). + +Shell biconvex, lenticular, with rounded circular margin; its horizontal +diameter three times as great as its thickness (or its vertical main axis). +Radial tubes cylindro-conical, straight, with six to nine triradiate +verticils, those of the margin of the lens twice as long as the smooth +tangential tubes, the others shorter. + +_Dimensions._--Horizontal diameter of the lens 5.5 mm., vertical main axis +0.2; length of the radial tubes 0.2, breadth 0.01. + +_Habitat._--Indian Ocean, Belligemma, Ceylon (Haeckel), surface. + + +2. _Aulophacus amphidiscus_, n. sp. (Pl. 111, fig. 5_b_). + +Shell discoidal, slightly biconvex, with rounded circular margin; its +horizontal diameter five times as great as its thickness. Radial tubes +cylindrical, covered with numerous short thorns, those of the margin of the +lens three times as long as the smooth tangential tubes, the others +shorter. + +{1632}_Dimensions._--Horizontal diameter of the lens 6.0, vertical main +axis 1.2; length of the radial tubes 0.2, breadth 0.005. + +_Habitat._--Indian Ocean, Madagascar (Rabbe), surface. + + + +Genus 687. _Aulatractus_,[306] n. gen. + +_Definition._--#Aulosphaerida# with triangular meshes in the network, the +tangential tubes of which form an ellipsoidal or spindle-shaped, simple +lattice-shell, with prolonged vertical main axis. Radial tubes arise at its +nodal points. + +The genus _Aulatractus_ differs from all the other Aulosphaerida in the +peculiar prolongation of the vertical axis of the lattice-sphere, by which +the latter becomes ellipsoidal or spindle-shaped. The triangular meshes of +the regular lattice-work become usually more or less irregular and +polygonal at the two poles of the elongated main axis. _Aulatractus_ seems +to be developed from _Aulosphaera_ in the opposite way from _Aulophacus_, +the former by elongating, the latter by shortening of the vertical +main-axis. + + +1. _Aulatractus fusiformis_, n. sp. (Pl. 111, figs. 6, 6_a_, 6_b_). + +Shell spindle-shaped, about twice as long as broad, rounded at both poles +of the main axis. Tangential tubes smooth, cylindrical. Radial tubes of the +same length as the tangential tubes, but much thinner, slender cylindrical, +studded with perpendicularly arising, short, lateral branches, which are +scattered in the proximal part, verticillate in the distal part, and bear a +spinulate terminal knob. + +_Dimensions._--Length of the shell 7.5 to 10.0, breadth 3.5; length of the +radial tubes 0.15 to 0.18, breadth 0.004. + +_Habitat._--Tropical Atlantic, Stations 348, 349; surface, and in various +depths. + + +2. _Aulatractus diploconus_, n. sp. (Pl. 111, fig. 7). + +Shell diploconical or nearly spindle-shaped, about three times as long as +broad, equally pointed at the two poles of the main axis, not inflated in +the middle part. Radial tubes slenderly conical, thorny, only half as long +as the smooth tangential tubes. + +_Dimensions._--Length of the shell 6.0 to 8.0, breadth 2.2 to 4.5; length +of the radial tubes 0.1 to 0.15, breadth 0.007. + +_Habitat._--North Atlantic, Canary Islands, Station 353, surface. + + +3. _Aulatractus fusulus_, n. sp. + +Shell spindle-shaped, about twice as long as broad, pointed at the two +equal poles of the main axis. Radial tubes cylindro-conical, smooth, about +as long as the smooth tangential tubes. This {1633}species resembles in its +simple structure the common cosmopolitan _Aulosphaera trigonopa_, and +differs from it only in the constant spindle-form of the shell. + +_Dimensions._--Length of the shell 6 to 8, breadth 3 to 4; length of the +radial tubes 0.16 to 0.2, breadth 0.008. + +_Habitat._--North Atlantic, Faeroee Channel, Gulf Stream (John Murray); +Hebrides (Moebius). + + +4. _Aulatractus ellipsoides_, n. sp. + +Shell ellipsoidal, about twice as long as broad, with equally rounded poles +on the main axis. Radial tubes straight, cylindrical, verticillate, about +twice as long as the smooth tangential bars; each verticil is cruciate, +composed of four rectangularly crossed, short, lateral branches which bear +a small spathilla at the distal end. + +_Dimensions._--Length of the shell 6.6, breadth 3.6; length of the radial +tubes 0.2, breadth 0.01. + +_Habitat._--South Atlantic, Station 332, surface. + + + +Subfamily 2. AULONIDA, Haeckel. + +_Definition._--Network of the shell with polygonal, usually irregular +meshes; three or four tangential tubes usually being united at each nodal +point. + + + +Genus 688. _Aulonia_,[307] n. gen. + +_Definition._--#Aulosphaerida# with polygonal meshes in the network, the +tangential tubes of which form a simple smooth lattice-sphere. No radial +tubes at the nodal points. + +The genus _Aulonia_ is the simplest form of the subfamily Aulonida, or of +those Aulosphaerida in which the lattice-work of the shell is composed not +of triangular but of polygonal meshes; all these Aulonida are much rarer +and much less differentiated than the Aularida or the common Aulosphaerida +with triangular meshes. _Aulonia_ has the same simple, smooth, spherical +lattice-shell as _Aularia_, and differs from it only in the polygonal form +of the meshes, which, however, is very constant. + + +1. _Aulonia tetragonia_, n. sp. + +Meshes regular or subregular, square, sometimes intermingled with a +variable number of irregular, triangular, and pentagonal meshes. Bars +cylindrical, of equal breadth. + +_Dimensions._--Diameter of the spherical shell 2.0 to 3.2, of the meshes +0.12 to 0.18; breadth of the bars 0.008. + +_Habitat._--Antarctic Ocean, Station 154, depth 1800 fathoms. + + +{1634}2. _Aulonia pentagonia_, n. sp. + +Meshes subregular, pentagonal, intermingled with a smaller number of +quadrangular and triangular irregular meshes. Bars cylindrical, of equal +breadth. + +_Dimensions._--Diameter of the spherical shell 2.8 to 3.2, of the meshes +0.15 to 0.2; breadth of the bars 0.01. + +_Habitat._--South Pacific, Stations 293 to 302, depth 1375 to 2270 fathoms. + + +3. _Aulonia hexagonia_, n. sp. (Pl. 111, fig. 1). + +Meshes regular or subregular, hexagonal, often intermingled with a variable +number of pentagonal and heptagonal meshes. Bars cylindrical, of equal +breadth. + +_Dimensions._--Diameter of the spherical shell 2.5 to 3.3, of the meshes +0.15 to 0.25; breadth of the bars 0.012. + +_Habitat._--Tropical Atlantic, Stations 347 to 349, surface. + + +4. _Aulonia metagonia_, n. sp. + +Meshes subregularly alternating, larger octagonal and smaller tetragonal. +The network of this remarkable species has a striking similarity to the +arrangement of the radial tubes in some species of _Sycon_, figured in my +Monograph of the Calcispongiae (1872, Bd. iii., Taf. ix. fig. 12). + +_Dimensions._--Diameter of the sphere 4.4, of the greater octagonal meshes +0.24 to 0.3, smaller tetragonal 0.1 to 0.12; breadth of the bars 0.007. + +_Habitat._--Indian Ocean, Cocos Islands (Rabbe), surface. + + +5. _Aulonia polygonia_, n. sp. + +Meshes irregular, polygonal, variable in form and unequal in size; the +majority usually pentagonal or hexagonal, but numerous intermingled meshes +with three, four, seven, or eight sides. Very variable in the size of the +bars and the form of the meshes. + +_Dimensions._--Diameter of the sphere 2.5 to 5.5, of the meshes 0.1 to 0.2; +breadth of the bars 0.008 to 0.12. + +_Habitat._--Cosmopolitan; Atlantic, Indian, Pacific, surface. + + + +Genus 689. _Aulastrum_,[308] n. gen. + +_Definition._--#Aulosphaerida# with polygonal meshes in the network, the +tangential tubes of which form a simple lattice-sphere. Radial tubes arise +at its nodal points. + +{1635}The genus _Aulastrum_ differs from the preceding _Aulonia_, its +ancestral form, only in the development of radial spines at the nodal +points of the simple lattice-sphere. It exhibits therefore to the latter +the same relation as _Aulosphaera_ does to _Aularia_. But the meshes of the +spherical network are constantly triangular in the two latter genera, +polygonal in the two former. The different species of _Aulastrum_ are much +rarer, and are not so differentiated as those of the common _Aulosphaera_. + + +1. _Aulastrum monoceros_, n. sp. + +Radial tubes simple, smooth, straight, cylindro-conical, about as long as +the smooth tangential tubes or somewhat longer. Meshes of the network +irregularly polygonal, the majority usually pentagonal or hexagonal. + +_Dimensions._--Diameter of the sphere 3.0 to 4.0, of the meshes 0.15; +breadth of the tubes 0.012. + +_Habitat._--Tropical Atlantic, Stations 347, 348, depth 2250 to 2450 +fathoms. + + +2. _Aulastrum dichoceros_, n. sp. + +Radial tubes cylindrical, more or less curved, undulate, smooth, twice as +long as the smooth tangential tubes, forked at the distal end, with two +divergent curved branches. Meshes of the network subregular, hexagonal (as +in _Aulonia hexagonia_, Pl. 111, fig. 1), intermingled with single +pentagonal and square meshes. + +_Dimensions._--Diameter of the sphere 2.0 to 2.5, of the meshes 0.12 to +0.18; breadth of the tubes 0.01. + +_Habitat._--Antarctic Ocean, Station 157, depth 1950 fathoms. + + +3. _Aulastrum dendroceros_, n. sp. (Pl. 111, figs. 4_a_, _b_, _c_). + +Radial tubes cylindrical, straight or slightly curved, thorny, forked at +the distal end, two to three times as long as the thorny tangential tubes; +the thorns are short and thin, partly simple, partly irregularly branched +and scattered, arborescent. Meshes of the network irregularly polygonal, +the majority pentagonal or tetragonal. + +_Dimensions._--Diameter of the sphere 2.4; radial tubes 0.2 to 0.3 long, +0.02 broad. + +_Habitat._--North Pacific, Station 241 to 244, surface. + + +4. _Aulastrum triceros_, n. sp. (Pl. 111, figs. 3, 3_a_). + +Radial tubes cylindrical, straight, smooth, about twice as long as the +smooth tangential tubes, armed with three divergent curved teeth at the +distal end. Meshes subregular, pentagonal, intermingled with a small number +of tetragonal and hexagonal meshes. + +_Dimensions._--Diameter of the sphere 1.2 to 1.8; radial tubes 0.15 long, +0.01 broad. + +_Habitat._--Tropical Atlantic, Station 349, depth 2450 fathoms. + + +{1636}5. _Aulastrum trichoceros_, n. sp. + +Radial tubes slender, straight, cylindro-conical, about twice as long as +the smooth tangential tubes, armed with six to eight verticils of lateral +branches, each of which is composed of three short curved branches (similar +to those of _Aulophacus lenticularis_, Pl. 111, fig. 5_a_). Meshes +irregularly polygonal, the majority tetragonal, intermingled with +pentagonal and triangular meshes. + +_Dimensions._--Diameter of the sphere 2.2; tangential tubes 0.12 long, +0.007 broad. + +_Habitat._--South Pacific, Station 289, depth 2550 fathoms. + + +6. _Aulastrum tetraceros_, n. sp. + +Radial tubes straight, cylindrical, about three times as long as the smooth +tangential meshes, armed with three to six subregular cruciate verticils of +branches, each of which is composed of four short, regularly crossed +branches, bearing at the end a spinulate knob (similar to those of +_Aulatractus fusiformis_, Pl. 111, fig, 6_b_). Meshes subregular, square, +intermingled with single pentagonal and hexagonal meshes. + +_Dimensions._--Diameter of the sphere 1.5, of the meshes 0.12 to 0.16; +breadth of the bars 0.008. + +_Habitat._--South Atlantic, Station 318, depth 2040 fathoms. + + +7. _Aulastrum pentaceros_, n. sp. + +Radial tubes straight, cylindrical, smooth, about as long as the smooth +tangential tubes, armed at the distal end with a corona of five curved +teeth (of the same shape as in _Cannosphaera atlantica_, Pl. 112, fig. 6). +Meshes subregular pentagonal (intermingled with single tetragonal, +hexagonal, and heptagonal meshes). + +_Dimensions._--Diameter of the sphere 5.0, of the meshes 0.2; breadth of +the bars 0.015. + +_Habitat._--Indian Ocean, Madagascar (Rabbe), surface. + + +8. _Aulastrum polyceros_, n. sp. + +Radial tubes spindle-shaped, tapering from the broader middle towards both +ends, spiny, twice as long as the spiny tangential tubes, armed at the +distal end with a corona of twelve to twenty divergent curved teeth +(similar to the radial tubes of _Auloscena tentorium_, Pl. 110, fig. 6). +Meshes irregular, polygonal, very variable in size and form. All tubes of +this species are armed with scattered, short, conical spines. + +_Dimensions._--Diameter of the sphere 4.5, of the meshes 0.1 to 0.2; +breadth of the bars 0.006. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +{1637}Genus 690. _Aulodictyum_,[309] Haeckel, 1879, Sitzungsb. med.-nat. +Gesellsch. Jena, Dec. 12, p. 6. + +_Definition._--#Aulosphaerida# with polygonal meshes in the network, the +tubes of which are connected in different directions and form the spongy +wall of a spherical shell. No radial tubes prominent over the surface. + +The genus _Aulodictyum_ differs from _Aulonia_, its ancestral form, in the +development of a spongy framework in the thickened wall of the spherical +lattice-shell. It bears therefore to the latter the same relation as +_Auloplegma_ does to _Aularia_. But the outer surface of the hollow sphere +is in _Aulodictyum_ completely smooth, as well as the inner, and bears no +radial tubes. Only one species of this genus has been observed. + + +1. _Aulodictyum hydrodictyum_, n. sp. + +Shell spherical, smooth on the outer and inner surfaces, composed of an +irregular framework of straight and smooth cylindrical tubes; its meshes +very irregular, of unequal size and various forms. The diameter of the +sphere is about six or eight times as great as the thickness of its +reticular wall. + +_Dimensions._--Diameter of the sphere 2 to 3, of its meshes 0.1 to 0.2; +breadth of the bars 0.01. + +_Habitat._--Antarctic Ocean, Station 157, depth 1950 fathoms. + + + +Family LXXVII. #CANNOSPHAERIDA#, Haeckel (Pl. 112). + + _Cannosphaerida_, Haeckel, 1879, Sitzungsb. med.-nat. Gesellsch. Jena, + Dec. 12, p. 6. + +_Definition._--PHAEODARIA with two concentric spherical or subspherical +shells, which are connected by numerous thin, tubular, radial beams. Inner +shell simple, spherical or ovate, solid or latticed, with a peculiar mouth. +Outer shell spherical or polyhedral, articulate, composed of hollow +tangential tubes, which are separated by astral septa at the stellate nodal +points. From the latter arise hollow radial tubes, whilst the inner radial +beams, connecting the two shells, are inserted in the middle of the +tangential tubes. No peculiar mouth in the outer shell. Central capsule +enclosed by the inner shell. + +The family #Cannosphaerida# comprises a small number of remarkable +PHAEODARIA which are rare and found only in a few localities. They differ +from all the other PHAEODARIA in the possession of two concentric spherical +shells, which are connected by radial beams, and the inner of which is +quite simple, like that of the Medusettida, {1638}whilst the outer is +articulated and composed of hollow tangential tubes, like that of the +Aulosphaerida. This latter family seems to be most nearly allied to the +Cannosphaerida, and is perhaps derived from them by loss of the inner +shell. The possession of a peculiar mouth in this inner shell brings the +Cannosphaerida nearer to the Phaeogromia. The similar Coelodrymida, in +which also two concentric spherical shells are connected by hollow radial +beams, differ essentially in the bivalved shape of the inner shell and the +simple, non-articulated, network of the outer shell. + +Only a single species of Cannosphaerida has been hitherto known, described +and figured in 1879 by R. Hertwig as _Coelacantha anchorata_ (_loc. cit._, +p. 92, Taf. ix. fig. 2). The rich collection of the Challenger has added to +it only four other species, one of which is most nearly allied to the +former, whilst the others belong to a separate genus, _Cannosphaera_ (Pl. +112). The inner shell is in this latter genus a solid lamella of silica, +whilst in the former it is fenestrated. In all other essential points of +structure both genera are scarcely different. + +The inner shell is either spherical or ovate and has a diameter of 0.1 to +0.4 (usually 0.2 to 0.3 mm.). A distinct main axis is always marked by the +large open mouth on its oral pole. The aboral part of the shell-cavity +contains the spherical central capsule, the oral part the dark phaeodium, a +part of which is often prominent through the mouth (figs. 1, 2, 4). The +wall of the inner shell is a very thin and transparent lamella of silica, +which is structureless and solid in _Cannosphaera_, distinctly fenestrated +in _Coelacantha_; the pores of the latter are irregularly rounded and seem +to possess a thickened margin. + +From the surface of the inner shell arise numerous thin tubular, radial +beams (twenty to eighty or more) and connect it with the outer shell. These +beams are always very thin and straight cylindrical tubules, about twice to +four times as long as the diameter of the inner shell, and usually 0.001 +mm. broad, or even less. Their basal end at the surface of the latter +appears mammillated (figs. 2, 4). The cavity of the inner shell seems to +pass over immediately into the tubular cavities of the radial beams. These +latter are sometimes simple, at other times articulated or jointed by a +number of transverse septa. The radial beams are covered in all the species +observed either with scattered spines (fig. 5) or with verticils of +anchor-threads, very thin, filiform, lateral branches which bear a +spathilla with three or four recurved teeth on the distal end (figs. 2, 4). + +The outer shell is either spherical or an endospherical polyhedron, the +prominent nodal points of which fall into a spherical face. Its diameter is +usually from 2 to 3 mm., rarely more than 3 or less than 1 mm. Its +structure is the same as described for the Aulosphaerida, being composed of +hollow cylindrical tubes, which form a loose network and are separated at +its nodal points by astral septa. The meshes of the network are {1639}very +large, usually twice to three times as broad as the inner shell, and +irregularly polygonal; the usual and prevailing form is pentagonal, but +hexagonal meshes are also often intermingled, more rarely meshes with five, +seven, or eight sides. + +The cylindrical tangential tubes possess in general the same shape as in +the similar Aulosphaerida, have a thin wall, are filled with jelly, and +contain a delicate axial filament in their axis; they differ, however, in a +peculiar constant character; in the middle of each tube is inserted an +inner radial beam coming from the inner shell, so that both together have +the form of a T. The central point of insertion has a somewhat shorter +radial distance from the centre of the body than the two nodal points on +both ends of the tangential tube, so that the latter is somewhat geniculate +(figs. 1-5). The two halves of each tangential tube are usually somewhat +thinner on the central end (where the inner radial beam is inserted), +thicker on the distal end (where the outer radial tube arises); at both +ends they are closed by a thin transverse septum. Often also some other +septa are developed, so that each tangential tube seems to be composed of +four to six joints or segments. Usually the tangential tubes are armed with +spines or anchor threads, similar to those of the inner radial beams. The +length of the single tangential tubes is usually between 0.1 and 0.3, their +diameter from 0.01 to 0.02. + +The nodal points of the outer lattice-sphere, in which the outer radial +spines arise, seem to possess the same structure as in the similar +Aulosphaerida. Since three tangential tubes are connected to each nodal +point, in its centre is the union of three small astral septa or sutural +partitions. The small nodal cavity on the inside of the nodal point has +probably three small pores, which lead into the three tangential tubes +between the three astral septa. A fourth pore probably leads from the nodal +cavity into the cavity of the hollow radial tube. This structure is +difficult to observe, but seems to be demonstrated by the fact, that in the +complete and carefully purified skeletons which are treated with hot +mineral acids and afterwards dried, all cylinders, the tangential as well +as the radial tubes, become easily filled by air (compare the description +of the similar structure in the Aulosphaerida). + +The external radial tubes which arise in the nodal points of the outer +shell are either cylindrical or cylindro-conical, straight, and usually +about as long as the diameter of the inner shell. Their structure and +armature is the same as in the similar Aulosphaerida. In the axis of each +radial tube runs a delicate axial filament, which is connected with its +thin and fragile wall either by filiform transverse branches or by delicate +transverse septa. The outside of the radial tubes is either smooth (figs. +3-5) or armed with scattered spines (fig. 4) or with verticils of lateral +branches; each verticil is usually composed of three or four branches. The +distal end of the radial tubes is rarely simple, pointed; it is usually +armed with a spathilla of three or four curved terminal branches (figs. 3, +5) sometimes with an elegant corona composed of twenty to thirty thin +radially divergent branches (fig. 4). + +{1640}The _central capsule_ of the Cannosphaerida is small (of 0.1 to 0.15 +in diameter) and hidden in the aboral half of the enclosing inner shell, +whilst the oral half of the latter is filled up by the phaeodium (figs. 2, +4). The structure of the capsule and of its three openings seems to be the +same as in the closely allied Aulosphaerida. I have, however, not been able +to recognise the two parapylae or secondary openings, and have only +observed the astropyle or the main-opening with its radiate operculum +surrounded by the phaeodium, and directed with its tubular proboscis +towards the mouth of the inner shell. As R. Hertwig also could not +recognise the two parapylae, it is not impossible that they are wanting, +and that the Cannosphaerida possess only one opening, the astropyle, like +the Medusettida and Challengerida. The nucleus, enclosed in the central +capsule, is spherical, half or one-third as broad as the latter, and +contains numerous nucleoli. + +_Synopsis of the Genera of Cannosphaerida._ + + Internal shell solid, without open pores, 691. _Cannosphaera_. + Internal shell latticed, with open pores, 692. _Coelacantha_. + + + +Genus 691. _Cannosphaera_,[310] Haeckel, 1879, Sitzungsb. med.-nat. +Gesellsch. Jena, Dec. 12, p. 6. + +_Definition._--#Cannosphaerida# with a solid, not latticed internal shell. + +The genus _Cannosphaera_ comprises those Cannosphaerida in which the inner +shell is formed by a thin solid siliceous-plate and exhibits no pores +between the prominent bases of the radial beams. + + +1. _Cannosphaera atlantica_, n. sp. (Pl. 112, figs. 5, 6). + +Internal shell not mammillate, with fifteen to twenty radial rods, which +are loosely studded with single, scattered, simple, lateral spines. +External shell with irregular, mostly hexagonal meshes, armed with numerous +scattered forks of paired divergent spines, and with twenty to thirty +larger simple radial spines, which are about half as long as the internal +rods, and bear at the distal end a verticil of three to five curved, +simple, terminal branches. + +_Dimensions._--Diameter of the inner shell 0.1, of the outer 0.5. + +_Habitat._--Tropical Atlantic, Stations 347 to 349, depth 2250 to 2450 +fathoms. + + +2. _Cannosphaera antarctica_, n. sp. (Pl. 112, figs. 1-3). + +Internal shell mammillate, with sixty to ninety radial rods, which are +studded with cruciate verticils of tridentate anchor-threads. External +shell with irregular, mostly pentagonal meshes, {1641}the bars of which +bear on the outside bunches of similar tridentate anchor-threads. At each +nodal point arises a simple, smooth, radial spine, which bears at the +distal end a verticil of three or four small, curved, terminal branches. + +_Dimensions._--Diameter of the inner shell 0.2 to 0.3, of the outer 1.5 to +2.0. + +_Habitat._--Antarctic Ocean, Stations 154 to 157, depth 1300 to 1975 +fathoms. + + +3. _Cannosphaera pacifica_, n. sp. (Pl. 112, fig. 4). + +Internal shell mammillate, with one hundred to one hundred and twenty +radial rods, which are studded with cruciate verticils of tridentate +anchor-threads. External shell with irregular, mostly hexagonal meshes, the +bars of which bear on the outside and on the inside bunches of similar +tridentate anchor-threads. At each nodal point arises a simple, thorny, +radial spine, which bears at the distal end an elegant verticil of fifteen +to twenty flatly expanded, thin, terminal branches. + +_Dimensions._--Diameter of the inner shell 0.25 to 0.35, of the outer 2.0 +to 2.5. + +_Habitat._--Central Pacific, Stations 270 to 274, depth 2350 to 2925 +fathoms. + + + +Genus 692. _Coelacantha_,[311] R. Hertwig, 1879, Organism. d. Radiol., p. +91. + +_Definition._--#Cannosphaerida# with a latticed internal shell. + +The genus _Coelacantha_ comprises those Cannosphaerida in which the inner +shell is formed by a fenestrated flint-plate, and exhibits numerous pores +between the prominent bases of the radial beams. + + +1. _Coelacantha anchorata_, R. Hertwig. + + _Coelacantha anchorata_, R. Hertwig, 1879, Organism. d. Radiol., p. 92, + Taf. ix. fig. 2. + +Internal shell slightly mammillate, with thirty to forty radial rods, which +are densely studded with verticils of tridentate anchor-threads. External +shell with irregular, mostly pentagonal meshes, the bars of which bear the +same verticils, each composed of three thin, tridentate anchor-threads. At +each nodal point arises a slender radial spine, which bears six verticils, +each composed of three to five lateral branches. + +_Dimensions._--Diameter of the inner shell 0.5, of the outer 3.0. + +_Habitat._--Mediterranean, Messina (R. Hertwig), surface. + + +2. _Coelacantha mammillata_, n. sp. + +Internal shell strongly mammillate, with sixty to eighty radial rods, which +are densely studded with cruciate verticils of quadridentate +anchor-threads. External shell with irregular, mostly {1642}hexagonal +meshes, the bars of which bear the same verticils, each composed of four +thin quadridentate anchor-threads. At each nodal point arises a slender, +smooth, radial spine, which bears at its distal end a verticil of four +large, curved, terminal branches. + +_Dimensions._--Diameter of the inner shell 0.4, of the outer 3.2. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +---- + + +Order III. PHAEOGROMIA, Haeckel, 1879. + +_Definition._--PHAEODARIA with a simple, not bivalved lattice-shell, which +assumes very different forms, but is always provided with a peculiar mouth +and peristome on the oral pole of the main axis. Central capsule always +excentric, placed in the aboral half of the shell-cavity. + + + +Family LXXVIII. #CHALLENGERIDA#, John Murray (Pl. 99). + + _Challengerida_, John Murray, 1876, Proc. Roy. Soc. Lond., vol. xxiv. p. + 471, pl. xxiv. figs. 1, 2. + +_Definition._--PHAEODARIA with a monaxonial, usually ovate or lenticular +shell, which exhibits a peculiar, fine, regularly hexagonal, diatomaceous +structure, and is usually provided with teeth on the mouth, but without +articulated feet. Central capsule excentric, placed in the aboral half of +the shell-cavity. + +The family #Challengerida# represent a large, peculiar, and interesting +group of PHAEODARIA, which are, for the most part, inhabitants of great +depths, and were perfectly unknown before the discoveries of the +Challenger. The first note on these remarkable Radiolaria was given in 1876 +by John Murray, in his Preliminary Reports on Work done on board the +Challenger (Proc. Roy. Soc. Lond., vol. xxiv. pp. 471, 536, pl. xxiv. figs. +1, 2). He described the peculiar exceedingly beautiful tracery of their +shell, similar to that of the Diatomaceae, the enclosed central capsule +coloured by carmine, and the surrounding mass of black-brown pigment lumps +(the phaeodium). "At times these Challengerida come up with a good deal of +sarcode outside of the shell, and two specimens have been seen to throw out +elongated pseudopodia" (_loc. cit._, p. 536). He found also the shells in +the Radiolarian ooze of the deep sea. The number of different forms found +in the collection of the Challenger is so great, that I can describe in the +following pages not less than six genera and fifty-eight species. A part of +these have already been figured by Dr. John Murray in the Narrative of the +Challenger Expedition, vol. i. p. 226, Pl. A, 1885. + +In my first preliminary note on the PHAEODARIA, in 1879, I gave a stricter +definition {1643}of the Challengerida (Sitzungsb. med.-nat. Gesellsch. +Jena, Dec. 12, 1879, p. 5). But I united at that time the true +Challengerida with the Tuscarorida, which, however, are sharply separated +by the entirely different structure of their shell. In Plate A given by Dr. +John Murray, and mentioned above, figs. 1-14 represent genuine +Challengerida, with diatomaceous shell-structure, whilst figs. 15-20 are +Tuscarorida, with porcellanous shell-structure. These latter, therefore, +are more closely allied to the Circoporida, whilst the Challengerida +exhibit a closer affinity to the Medusettida and Castanellida. But the two +latter families never possess that peculiar extremely regular and delicate +diatomaceous structure which is exhibited only by the Challengerida. + +The general form of the Challengerida is rather simple, usually more or +less ovate, sometimes nearly triangular, at other times subspherical. In +nearly all species, with a few exceptions, the shell is more or less +compressed from the two sides, so that its horizontal transverse section is +not circular, but elliptical or lanceolate. In many species the shell is +more or less lenticular, with a sharp or sometimes keeled margin. This +margin lies in the sagittal plane of the body, whilst the two flat sides +are right and left. The main axis is always perpendicular, and its oral or +anterior pole is marked by the open mouth of the shell; the latter is in +the living organism probably the upper pole, whilst the opposite aboral or +posterior pole (often marked by large spines) is the lower pole. The dorsal +margin of the mouth is usually different from the ventral, and in the +majority of species this difference is so striking, that right and left +sides of the body may be recognised immediately, the fundamental form being +dipleuric or bilaterally-symmetrical. In a few species, however, and mainly +in those simplest forms in which the ovate shell has a circular mouth +without teeth, and a circular transverse section, that difference is not +recognisable, and the ovate shell is monaxonial, as it is in _Gromia_ and +_Lagena_ among the Foraminifera (Pl. 99, figs. 19, 20, 22). The size of the +shell is in the majority of species between 0.2 and 0.5 mm.; there are, +however, some very small species, in which the diameter of the shell is +only 0.05 to 0.08, or even less; and some large species, the diameter of +which attains 0.8 to 0.9 mm. + +The peculiar structure of the siliceous shell-wall, which we call shortly +"diatomaceous," and by which the Challengerida differ from all the other +PHAEODARIA, has been already represented very well by Dr. John Murray, in +Pl. A. of the Narrative (vol. i. p. 266, figs. 1_c_-1_e_, 2_a_, 4_a_, 7_a_, +7_b_). This elegant diatomaceous structure is extremely similar or nearly +identical with that well-known regular structure which we find in the +common Diatomaceae or Bacillariae. The entire surface of the shell is +covered with a very great number of very small pit-like depressions, +perfectly regular, circular in form, equal in size, and quincuncial in +arrangement. The neighbouring equidistant pits are always surrounded by +regular hexagonal frames of equal size, and the prominent fine crests of +these frames produce the regular hexagonal tracery, which gives to the +shell such a striking similarity to that of the Diatomaceae. According to +{1644}the different positions to which the focus of the microscope is +brought, the hexagonal tracery exhibits a different appearance; either a +regular network of equal hexagonal frames, or a lattice with equal and +equidistant circular openings, or a combination of three crossed and +equidistant systems of parallel lines (crossed at angles of 120d). All the +well-known and often discussed optical phenomena which are observed in the +valves of the Diatomaceae, reappear also on the shell of the Challengerida. + +To recognise the true nature of this diatomaceous structure, sections and +slides of the shell are required, and also fragments of broken shells, the +broken margins of which are of special value for obtaining further +explanation. The figures given by Dr. J. Murray (_loc. cit._, Pl. A) have +already demonstrated that the pit-like depressions are regular small +cavities in the flinty shell-wall, which possess an inner and an outer +opening. These intraparietal cavities are either spherical (fig. 7_b_) or +cylindrical (fig. 1_d_, 4_a_) or spindle-shaped, with a constriction (fig. +2_a_). Further accurate examinations probably will show a greater variety +in their shape. But each cavity constantly possesses two small openings, +one on the outer, and the other on the inner surface of the shell-wall. +Closer examination (especially of broken shells and slides) proves the +presence of these two openings, which in the smaller species seem to be +absent on the first view. I may, therefore, suppose that also in the +similar valves of the Diatomaceae, which exhibit exactly the same +structure, an inner and an outer opening are always present in each +hexagonal pit, and that the very small size alone prevents them from being +recognised. The regular hexagonally-framed cavities in the shell-wall of +the Challengerida (probably also of the Diatomaceae) are therefore genuine +pores, differing from the pores of other Radiolaria only in their smaller +size and the dilatation of the middle part, which is much wider than the +two openings. + +The mouth of the shell, its single larger opening, exhibits in the various +Challengerida a great variety in form and structure, and offers the best +means for separating genera and species. According to its essential shape +two different subfamilies and six genera may be distinguished in this +family. In the first subfamily, Lithogromida, the mouth is a simple large +opening in the wall of the shell on the oral pole of its main axis (Pl. 99, +figs. 1-15). In the second subfamily, Pharyngellida, the mouth is prolonged +into a cylindrical hollow tube, which is prominent into the shell-cavity, +and comparable to the pharynx of the Metazoa in general form and function +(Pl. 99, figs. 16-20). In this case we may distinguish an inner and an +outer mouth of the tubular pharynx. + +In a few forms of both subfamilies the mouth is toothless, smooth, and not +armed with prominent external spines or teeth, as in _Lithogromia_, the +simplest form of all (Pl. 99, fig. 22) and in _Entocannula_ (figs. 19, 20). +In the great majority of Challengerida, however, the outer opening of the +mouth is armed with one or more teeth, usually strong prominent spines +(figs. 1-18). Usually the base of these teeth is {1645}semitubular or a +half cylinder, forming a more or less prominent peristome or a proboscis; +and always in this case the open concave side of the canal-shaped groove is +directed towards the ventral side of the shell, the closed convex side +towards the dorsal side. When several teeth arise from the two lateral free +margins of the groove, they are also directed towards the ventral side +(figs. 2, 12, 17, &c.). Often a deep ventral incision or a guttural +constriction separates the base of the proboscis from the genuine shell. +The structure of this proboscis or peristome is usually the same as in the +diatomaceous shell-wall; but sometimes its lattice-work assumes a different +shape. + +The opening of the mouth itself is rarely circular, usually it is +elliptical or even lanceolate, often triangular. Sometimes two prominent +opposite lips may be distinguished as right and left, when the fissure of +the mouth is prolonged in a sagittal or longitudinal direction; as upper +and lower, when it is prolonged in a frontal or transverse direction. The +upper or dorsal lip is always more developed than the lower or ventral; and +the entire semitubular proboscis may be regarded as a production of the +upper lip. Sometimes the latter attains an extraordinary size and +development, the greatest in _Challengeria murrayi_ (Pl. 99, fig. 1). + +The teeth of the mouth, which arise from the upper lip, are usually hollow, +at least on the base; a prolongation of the shell-cavity arising into the +base of the teeth. Their form is very variable, conical, lanceolate, +triangular, sabre-shaped, &c. Usually they are more or less curved, and +shorter than the radius of the shell; rarely they are straight, and longer +than the radius (Pl. 99, figs. 5, 6). More important is their different +number, which we have employed for the distinction of subgenera; future +observations may prove that they are different genera. The most important +are the following cases:--(A.) a single odd dorsal tooth (figs. 5, 16); +(B.) two paired lateral teeth (figs. 4, 6, 17); (C.) three teeth, an odd +dorsal and two paired lateral (figs. 7, 9, 10); (D.) four paired teeth, two +dorsal and two ventral (figs. 3, 13); (E.) five teeth, an odd dorsal and +two pairs of lateral (figs. 2, 12); (F.) six teeth in three lateral pairs +(fig. 1). + +The teeth of the peristome are not the only apophyses which arise from the +shell of the Challengerida. In the majority other spines appear on the +sagittal margin, which separates the right and left halves of the shell. +These marginal spines are characteristic of the genera _Challengeron_ and +_Porcupinia_; they are usually radially directed, straight, conical, +sometimes solid, at other times hollow. Their number and arrangement is +very variable and serves for the distinction of species; the following +differences are the most important:--(A.) a single odd spine on the apical +pole of the shell, in the principal axis, opposite to the centre of the +mouth (Pl. 99, figs. 6, 7); (B.) two aboral spines, a dorsal and a ventral +(figs. 8-10); (C.) a bunch or a crowded group of radial spines on the +aboral margin of the shell, usually one larger apical spine surrounded by +several smaller dorsal and ventral (figs. 11, 12, 16); (D.) numerous radial +spines along the whole sagittal margin of the shell (figs. 13-15). + +{1646}The _central capsule_ of the Challengerida is constantly placed in +the aboral half of the shell-cavity, whilst its oral half is occupied by +the phaeodium; the intervals between them and the inner surface of the +shell are filled up by the calymma. Frequently from the outer surface of +the capsule arise numerous branched streams of sarcode, which pierce the +calymma and are directed towards the inside of the shell-wall, where they +are united by a thin continuous layer of protoplasm (Pl. 99, fig. 1). The +phaeodium is usually more voluminous than the capsule and envelops the +latter on its anterior or oral face; more rarely the entire capsule is +hidden in the phaeodium. The phaeodella, constituting the latter, are of +very different sizes, of variable colour, olive and greenish-brown, +red-brown, black-brown or nearly black. In some preparations, stained with +carmine, numerous red coloured granula, similar to nuclei, were scattered +in the phaeodium (compare Murray, _loc. cit._, Pl. A, figs. 1-14). + +The diameter of the central capsule is usually about one-half or one-third +as great as that of the enclosing shell (Pl. 99, figs. 1-20). Its form is +either spherical or slightly compressed, spheroidal, or sometimes +lenticular. The large nucleus has the same form, is about half as broad as +the capsule and contains numerous nucleoli. Sometimes the capsule contained +two nuclei of equal size, and in a few specimens the shell contained two +central capsules, each with a nucleus, so that the Challengerida seem to +propagate also by self-division (Pl. 99, fig. 6). + +The astropyle, or the large opening of the central capsule, exhibits the +usual radiate operculum of the PHAEODARIA, and the tubular proboscis +arising from it. This is constantly placed on the oral or anterior pole of +the capsule and directed towards the mouth of the shell. I was never able +to discover any parapyle or secondary opening in the central capsule, +though numerous and well-preserved specimens of the Challenger collection +were accurately examined. It seems therefore that the Challengerida are not +TRIPYLEA (as the majority of PHAEODARIA), but MONOPYLEA with a single +opening (like the closely allied Medusettida and Castanellida). + +_Synopsis of the Genera of Challengerida._ + + { Shell smooth, without + { adoral teeth and + { marginal spines, 693. _Lithogromia_. + I. Subfamily Lithogromida. { + Shell without pharynx { Shell with adoral + or inner prominent tube { teeth, but without + of the mouth. { marginal spines, 694. _Challengeria_. + { + { Shell with adoral + { teeth and with + { marginal spines, 695. _Challengeron_. + + { Shell smooth, without + { adoral teeth and + II. Subfamily Pharyngellida.{ marginal spines, 696. _Entocannula_. + Shell with a pharynx, { + or an inner cylindrical { Shell with adoral + tube, arising from the { teeth, but without + mouth and prominent { marginal spines, 697. _Pharyngella_. + inside. { + { Shell with adoral + { teeth and with + { marginal spines, 698. _Porcupinia_. + + + +{1647}Subfamily 1. LITHOGROMIDA, Haeckel. + +_Definition._--#Challengerida# without pharynx, with a simple mouth, not +prolonged into an inner prominent tube. + + + +Genus 693. _Lithogromia_,[312] Haeckel, 1879, Sitzungsb. med.-nat. +Gesellsch. Jena, Dec. 12, p. 5. + +_Definition._--#Challengerida# without pharynx, without adoral teeth and +marginal spines. + +The genus _Lithogromia_ and the two following genera represent together the +subfamily Lithogromida, comprising those Challengerida in which the mouth +of the shell is a simple opening, and not prolonged into a pharynx or an +internal prominent tube. _Lithogromia_ may be regarded as the common +ancestral form of this family, since it is the simplest of all, and +possesses no external apophyses, neither teeth on the mouth, nor spines on +the margin of the smooth shell. + + +1. _Lithogromia silicea_, n. sp. (Pl. 99, fig. 22). + +Shell ovate, one and a half times as long as broad, not compressed. +Transverse section circular. Mouth a simple circular opening with smooth +edges about one-third as broad as the shell. + +_Dimensions._--Length of the shell 0.2, breadth 0.15; mouth 0.05. + +_Habitat._--North Atlantic, Faeroee Channel (Gulf Stream), John Murray, +depth 600 fathoms. + + +2. _Lithogromia diatomacea_, n. sp. (Pl. 99, fig. 21). + +Shell ovate, lenticular, one and one-third times as long as broad, strongly +compressed. Transverse section elliptical. Mouth a broad fissure, half as +broad as the shell. + +_Dimensions._--Length of the shell 0.27, breadth 0.2; mouth 0.1. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + +3. _Lithogromia lenticula_, n. sp. + +Shell subcircular, lenticular, about as long as broad, strongly compressed. +Transverse section lanceolate. Mouth a narrow fissure, one-third as broad +as the shell. + +_Dimensions._--Diameter of the shell 0.15, mouth 0.05. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + + +{1648}Genus 694. _Challengeria_, John Murray, 1876, Proc. Roy. Soc. Lond., +vol. xxiv. p. 536. + +_Definition._--#Challengerida# without pharynx, with one or more adoral +teeth, but without spines on the sagittal margin. + +The genus _Challengeria_, and the following closely allied _Challengeron_, +differ from the preceding _Lithogromia_, their ancestral form, in the +development of teeth on the mouth of the shell. _Challengeron_ has also +radial spines on the sagittal margin, while these are wanting in +_Challengeria_. The latter genus exhibits not less than twenty-one, the +former twenty-five species, so that both together make by far the greatest +part of the family (containing fifty-eight species). They are also more +common and more widely distributed than the four other genera of +Challengerida, and many species appear in great numbers in certain +localities. With a few exceptions living on the surface, they are all +inhabitants of great depths. + + + +Subgenus 1. _Challengerantha_, Haeckel. + +_Definition._--Peristome with a single simple tooth, which is neither +forked nor branched (_Challengeriae monodontes_). + + +1. _Challengeria naresii_, John Murray. + + _Challengeria naresii_, John Murray, 1876, Proc. Roy. Soc. Lond., vol. + xxiv. pl. xxiv. fig. 1. + + _Challengeria naresii_, John Murray, 1879, _in litteris_, Narr. Chall. + Exp., vol. i. p. 236, pl. A, figs. 1, 1_a_-1_e_. + +Shell circular or nearly circular, strongly compressed, lenticular. +Peristome on the dorsal corner with a single simple vertical tooth, which +is nearly straight, conical, with two sharp lateral edges on the base, +about half as long as the shell. + +_Dimensions._--Diameter of the shell 0.5 to 0.6, length of the tooth 0.2 to +0.3. + +_Habitat._--Cosmopolitan; Atlantic, Indian, Pacific, at depths between 1000 +and 3000 fathoms. + + +2. _Challengeria xiphodon_, n. sp. + +Shell circular, nearly spherical, slightly compressed. Peristome on the +dorsal corner with a single simple vertical tooth, which is straight, +three-sided prismatic, and as long as the shell. + +_Dimensions._--Diameter of the shell 0.1 to 0.13, length of the tooth 0.1 +to 0.12. + +_Habitat._--Tropical Atlantic, Stations 349 to 352, surface. + + +{1649}3. _Challengeria sigmodon_, n. sp. + +Shell circular, nearly spherical, slightly compressed. Peristome with a +single simple tooth, which is S-shaped, more or less curved, and about +one-third as long as the shell. + +_Dimensions._--Diameter of the shell 0.3 to 0.4, length of the tooth 0.1 to +0.14. + +_Habitat._--North Pacific, Station 231, depth 2250 fathoms. + + +4. _Challengeria tritonis_, n. sp. (Pl. 99, fig. 5). + +Shell ovate, slightly compressed. Peristome with a single simple tooth, +which is vertical, straight, slenderly conical, and about half as long as +the shell. + +_Dimensions._--Diameter of the shell 0.15 to 0.2, length of the tooth 0.1 +to 0.12. + +_Habitat._--North Atlantic, Faeroee Channel, Gulf Stream, in great numbers, +in depths from 100 to 600 fathoms. (Expedition of H.M.S. "Triton," 1882), +John Murray. + + +5. _Challengeria pyramidalis_, n. sp. + +Shell slenderly ovate, one and a half times as long as broad, slightly +compressed. Peristome with a single, simple, large tooth, which is +three-sided pyramidal, vertical, straight, and longer than half the shell. + +_Dimensions._--Length of the shell 0.6 to 0.8, breadth 0.4 to 0.5; length +of the tooth 0.4 to 0.5. + +_Habitat._--South Atlantic, Station 318, depth 2040 fathoms. + + +6. _Challengeria cyrtodon_, n. sp. + +Shell ovate, lenticular, strongly compressed. Peristome with a single +simple tooth, which is crescent-shaped, curved over the mouth, and about +half as long as the shell. + +_Dimensions._--Length of the shell 0.4 to 0.5, breadth 0.3 to 0.4; length +of the tooth 0.2 to 0.25. + +_Habitat._--South Pacific, Station 289, depth 2550 fathoms. + + + +Subgenus 2. _Challengeretta_, Haeckel. + +_Definition._--Peristome with a forked or bifid tooth, or with two parallel +lateral teeth (_Challengeria diodontes_). + + +7. _Challengeria sloggettii_, John Murray (Pl. 99, fig. 4). + + _Challengeria harstoni_, John Murray, 1879 (_partim_), _in litteris_, + Narr. Chall. Exp., vol. i. p. 226, pl. A, fig. 14. + +Shell triangular, strongly compressed, with three rounded corners, or +nearly semicircular; its aboral margin straight, horizontal, longer than +the convex, dorsal, and ventral margins. Peristome {1650}with two parallel, +triangular pointed teeth, which are obliquely ascending, lamellar, with +inflated ovate base, and about as long as the shell-radius. + +_Dimensions._--Diameter of the shell 0.2 to 0.3, length of the teeth 0.1 to +0.15. + +_Habitat._--Tropical Atlantic, Stations 347, 348, depth 2250 to 2450 +fathoms. + + +8. _Challengeria harstoni_, John Murray. + + _Challengeria harstoni_, John Murray, 1879, _in litteris_, Narr. Chall. + Exp., vol. i. p. 226, pl. A, fig. 14_a_. + +Shell subcircular or somewhat triangular, with convex margins. Peristome +with two parallel, slender, lanceolate teeth, which are obliquely +ascending, and about half as long as the shell-radius. + +_Dimensions._--Diameter of the shell 0.15 to 0.18, length of the teeth 0.04 +to 0.05. + +_Habitat._--North Pacific, Station 231, depth 2250 fathoms. + + +9. _Challengeria campbelli_, John Murray. + + _Challengeria campbelli_, John Murray, 1879, _in litteris_, Narr. Chall. + Exp., vol. i. p. 226, pl. A, fig. 9. + +Shell cordate, nearly triangular, compressed, with blunt apex. Peristome in +the excavated middle of the broad base, with two short, parallel, +triangular teeth. This species is very similar to _Porcupinia cordiformis_ +(Pl. 99, fig. 16), but differs from it in the absence of an internal +pharynx and of external apical spines. + +_Dimensions._--Diameter of the shell 0.2 to 0.24; length of the teeth 0.03 +to 0.05. + +_Habitat._--South Atlantic, Stations 332 to 335, depth 1425 to 2200 +fathoms. + + +10. _Challengeria thomsoni_, John Murray. + + _Challengeria thomsoni_, John Murray, 1879, _in litteris_, Narr. Chall. + Exp., vol. i. p. 226, pl. A, fig. 2. + +Shell ovate, slightly compressed, with rounded apical pole. Peristome +semitubular, obliquely ascending, nearly straight, in the lower half an +open half-cylinder, in the upper half forked, with two parallel, thin, +oblique teeth. Sometimes a third small (dorsal) tooth is developed. + +_Dimensions._--Length of the shell 0.3 to 0.35, breadth 0.2 to 0.25; length +of the peristome 0.08 to 0.12. + +_Habitat._--South Atlantic, Stations 318 to 330, surface, and in depths +from 1900 to 2900 fathoms. + + +11. _Challengeria bidens_, n. sp. + +Shell ovate, strongly compressed, lenticular. Peristome with two curved, +long and thin bristle-shaped teeth, which are obliquely inclined over the +mouth, and longer than the radius of the shell. + +_Dimensions._--Length of the shell 0.12 to 0.18, breadth 0.1 to 0.14; +length of the teeth 0.08 to 0.1. + +_Habitat._--Central Pacific, Stations 271 to 274, depth 2350 to 2750 +fathoms. + + +{1651}12. _Challengeria havergalli_, John Murray. + + _Challengeria havergalli_, John Murray, 1879, _in litteris_, Narr. Chall. + Exp., vol. i. p. 226, pl. A, figs. 13, 13_a_. + +Shell subspherical, slightly compressed. Peristome semitubular, slender, +somewhat curved, in the lower half a simple half-cylinder, in the upper +half forked, with two divergent teeth, nearly as long as the shell. + +_Dimensions._--Diameter of the shell 0.1 to 0.15, length of the peristome +0.08 to 0.12. + +_Habitat._--South Pacific, Station 300, depth 1375 fathoms. + + +13. _Challengeria elephas_, n. sp. + +Shell ellipsoidal, not compressed. Peristome very similar to that of +_Challengeron diodon_ (Pl. 99, fig. 6), from which this species differs +mainly in the absence of an apical spine, and in a more constricted mouth. +The two conical teeth of the mouth are very large, nearly as long as the +shell, straight, and almost parallel, each tooth has a large hole on the +thickened base. + +_Dimensions._--Diameter of the shell 0.22, length of the teeth 0.2. + +_Habitat._--Indian Ocean, Cocos Islands (Rabbe), surface. + + + +Subgenus 3. _Challengerilla_, Haeckel. + +_Definition._--Peristome with three teeth or trifid, with an odd dorsal and +two paired lateral teeth (_Challengeriae triodontes_). + + +14. _Challengeria macleari_, John Murray. + + _Challengeria macleari_, John Murray, 1879, _in litteris_, Narr. Chall. + Exp., vol. i. p. 226, pl. A, fig. 3. + +Shell subcircular, lenticular, with a sharp marginal edge. Peristome +semitubular, an oblique half-cylinder, with three divergent, short, +triangular teeth; the dorsal odd tooth nearly vertical, the paired lateral +teeth subhorizontal. Length of the peristome about one-third or one-fourth +of the diameter of the shell. + +_Dimensions._--Diameter of the shell 0.25 to 0.35, length of the peristome +0.1 to 0.12. + +_Habitat._--South Atlantic, Stations 325 to 332, depth 1715 to 2900 +fathoms. + + +15. _Challengeria tridens_, n. sp. + +Shell subspherical, slightly compressed. Peristome about as long as the +radius of the shell, with three diverging and obliquely descending teeth; +the dorsal odd tooth twice as long as the paired lateral teeth. + +_Dimensions._--Diameter of the shell 0.08 to 0.12, length of the peristome +0.05 to 0.07. + +_Habitat._--North Atlantic, Faeroee Channel (Gulf Stream), John Murray. + + +{1652}16. _Challengeria trigona_, Haeckel. + + _Challengeria macleari_, var., John Murray, 1879, _in litteris_, Narr. + Chall. Exp., vol. i. p. 226, pl. A, fig. 3_b_. + +Shell triangular, with three rounded corners; the two lateral sides nearly +straight, equal, the aboral side more or less convex and somewhat shorter. +Peristome a curved half-tube (often longer than in Murray's figure), +one-third to one-half as long as the shell, with three short triangular +diverging and ascending teeth of equal length. + +_Dimensions._--Length of the shell 0.25 to 0.3, breadth 0.2 to 0.25; length +of the peristome 0.08 to 0.12. + +_Habitat._--South Atlantic, Stations 332 to 335, depth 1425 to 2200 +fathoms. + + +17. _Challengeria trifida_, n. sp. + +Shell ovate, more or less compressed, about two-thirds as long as broad. +Peristome semitubular, obliquely ascending, about one-third as long as the +shell, in the lower half simple, in the upper trifid, with three curved +divergent teeth; the dorsal odd tooth shorter than the paired lateral +teeth. + +_Dimensions._--Length of the shell 0.3 to 0.36, breadth 0.24 to 0.28. + +_Habitat._--South Pacific, Station 289, depth 2550 fathoms. + + + +Subgenus 4. _Challengeromma_, Haeckel. + +_Definition._--Peristome with four to six or more teeth. + + +18. _Challengeria quadridens_, n. sp. + +Shell subglobose, with nearly circular perimeter. Peristome an oblique +short and broad tube, the breadth of which is twice as great as its length +and equal to the radius of the shell. Margin of the peristome with four +divergent, short, triangular teeth, the two dorsal teeth half as long as +the two ventral. + +_Dimensions._--Diameter of the shell 0.22 to 0.24, breadth of the peristome +0.1. + +_Habitat._--Central Pacific, Stations 265 to 268, depth 2700 to 2900 +fathoms. + + +19. _Challengeria bromleyi_, n. sp. (Pl. 99, fig. 3). + +Shell ovate, lenticular, strongly compressed. Peristome a broad, +trapezoidal, horizontal lamella, the breadth of which is twice as great as +its length and nearly equal to the diameter of the shell; its margin with +four divergent triangular lamellar teeth, the two dorsal teeth three times +as long as the two ventral. + +_Dimensions._--Length of the shell 0.08 to 0.1, breadth 0.05 to 0.07; +breadth of the peristome 0.08. + +_Habitat._--North Pacific, Stations 244 to 253, surface, and in various +depths. + + +{1653}20. _Challengeria wildi_, n. sp. (Pl. 99, fig. 2). + +Shell subspherical, slightly compressed. Peristome semitubular, curved, as +long as the shell-radius; with five curved lamellar teeth, an odd longer +dorsal tooth and two pairs of lateral teeth. + +_Dimensions._--Diameter of the shell 0.12 to 0.18, length of the peristome +0.08 to 0.12. + +_Habitat._--Tropical Atlantic, Stations 347 to 348, depth 2250 to 2450 +fathoms. + + +21. _Challengeria aldrichi_, John Murray, _Challengeria aldrichi_1876, L. +N. 27, pl. 24, fig. 2. + + _Challengeria aldrichi_, John Murray, 1879, in litteris, Narr. Chall. + Exp., vol. i. p. 226, pl. A, fig. 4. + +Shell subspherical, slightly compressed. Peristome a collar-like curved +lamella, the breadth of which is twice as great as its length, and equals +the radius of the shell; its margin with six short triangular teeth, two +convergent ventral, two external horizontal lateral, and two ascending +dorsal. + +_Dimensions._--Diameter of the shell 0.2, breadth of the peristome 0.1. + +_Habitat._--North Pacific, Station 244 to 248, depth 2050 to 2900 fathoms. + + +22. _Challengeria murrayi_, n. sp. (Pl. 99, fig. 1). + +Shell subcircular, lenticular, strongly compressed. Peristome a +trapezoidal, curved, collar-like lamella, the breadth of which is three +times as great as its length and equal to the diameter of the shell; its +margin with six triangular teeth, disposed like the preceding species, but +larger. + +_Dimensions._--Diameter of the shell 0.15, breadth of the peristome 0.15. + +_Habitat._--North-Western Pacific (south of Japan), Station 231, depth 2250 +fathoms. + + + +Genus 695. _Challengeron_, John Murray, 1879, _in litteris et schedulis_. + +_Definition._--#Challengerida# without pharynx, with one or more teeth on +the mouth, and with marginal spines. + +The genus _Challengeron_ has in general the same shape as the preceding +closely allied _Challengeria_, but differs from it in the development of +radial spines on the sagittal margin of the shell, which in the latter +genus is smooth. According to the different number and arrangement of these +marginal spines, which give a very singular appearance to them, we divide +the twenty-five species of this cosmopolitan genus into four +subgenera:--(1) with a single, odd apical spine; (2) with two opposed +aboral spines (a dorsal and a ventral); (3) with a bunch of aboral spines; +(4) with numerous radial spines along the whole sagittal margin of the +shell. + + + +Subgenus 1. _Challengeranium_, Haeckel. + +_Definition._--Margin of the shell with a single spine on the apical pole, +opposite to the peristome (_Challengeriae caudatae_). + + +{1654}1. _Challengeron monodon_, n. sp. + +Shell subspherical, slightly compressed, with a single straight conical +spine on the apical pole, about as long as the radius. Peristome with a +single vertical, straight, conical tooth, diametrically opposite to the +apical spine and of the same length. (Similar to _Challengeria naresii_.) + +_Dimensions._--Diameter of the shell 0.2 to 0.3, length of the two opposite +spines 0.1 to 0.15. + +_Habitat._--Central Pacific, Stations 270 to 274, depth 2350 to 2925 +fathoms. + + +2. _Challengeron cochlear_, n. sp. + +Shell nearly circular, lenticular, strongly compressed, with a single +straight conical spine on the apical pole, about half as long as the +radius. Peristome spoon-shaped, obliquely curved and inclined over the +mouth, with a single terminal tooth, somewhat longer than the radius. + +_Dimensions._--Diameter of the shell 0.1, length of the peristome 0.06. + +_Habitat._--Indian Ocean, Cocos Islands, Rabbe, surface. + + +3. _Challengeron diodon_, n. sp. (Pl. 99, fig. 6). + +Shell ovate, slightly compressed, with a single straight conical spine on +the aboral pole, half as long as the radius. Peristome short and broad, +collar-shaped, about twice as broad as long, and half as long as the +radius, obliquely inclined over the mouth, with two divergent straight +teeth, which are conical and longer than the shell-radius; beyond each +tooth a large ovate hole in the wall of the peristome. + +_Dimensions._--Diameter of the shell 0.08 to 0.1, length of the teeth 0.06 +to 0.08. + +_Habitat._--South-Eastern Pacific, Station 298, depth 2225 fathoms. + + +4. _Challengeron pearceyi_, n. sp. (Pl. 99, fig. 7). + +Shell ellipsoidal or subspherical, scarcely compressed, with a single +straight conical spine on the apical pole, about as long as the diameter. +Peristome slender, semitubular, nearly as long as the diameter, somewhat +obliquely inclined over the mouth, with three divergent triangular or +lanceolate teeth; the dorsal odd tooth about twice as large as the paired +lateral teeth. + +_Dimensions._--Diameter of the shell 0.08 to 0.12, length of the peristome +0.08 to 0.1. + +_Habitat._--Antarctic Ocean, between Kerguelen and Heard Island, Station +157. + + +5. _Challengeron swirei_, John Murray. + + _Challengeria swirei_, John Murray, 1879, _in litteris_, Narr. Chall. + Exp., vol. i. p. 226, pl. A, fig. 11. + +Shell subspherical or somewhat ovate, with a single straight conical spine +on the apical pole, about as long as the radius. Peristome slender, +semitubular, straight and vertical, nearly as long as the shell, with three +pointed teeth, an odd longer terminal and two paired shorter lateral. + +_Dimensions._--Diameter of the shell 0.06 to 0.08, length of the peristome +0.05 to 0.06. + +_Habitat._--Antarctic Ocean, Station 157, surface, common. + + +{1655}6. _Challengeron triodon_, n. sp. + +Shell ovate, one and a half times as long as broad, not compressed, with a +single short and stout conical spine on the apical pole, shorter than half +the radius. Peristome short and broad, collar-shaped, nearly half as broad +and one-third as long as the shell, with three divergent terminal teeth, an +odd dorsal and two paired lateral. + +_Dimensions._--Length of the shell 0.25 to 0.3, breadth 0.15 to 0.2; length +and breadth of the peristome 0.1. + +_Habitat._--North Pacific, Station 245, surface. + + + +Subgenus 2. _Challengerebium_, Haeckel. + +_Definition._--Margin of the shell with two widely distant aboral spines, +opposite in the sagittal plane, a dorsal and a ventral. + + +7. _Challengeron balfouri_, John Murray. + + _Challengeria balfouri_, John Murray, 1879, _in litteris_, Narr. Chall. + Exp., vol. i. p. 226, pl. A, fig. 10. + +Shell subcircular, lenticular, strongly compressed, with two short +divergent spines on the apical margin (a dorsal and a ventral). Peristome +slender, semitubular, as long as the radius, vertical, in the distal half +forked, with two parallel teeth. + +_Dimensions._--Diameter of the shell 0.08 to 0.16, length of the peristome +0.04 to 0.08. + +_Habitat._--North Atlantic, Stations 353 to 354, Hebrides, surface. + + +8. _Challengeron golfense_, n. sp. + +Shell ovate, lenticular, compressed, with two short divergent spines on the +apical margin (a dorsal and a ventral). Peristome slender, semitubular, +half as long as the radius, with three terminal teeth, two short, +vertically ascending, paired teeth and a larger odd tooth, which is +inclined obliquely over the mouth. + +_Dimensions._--Diameter of the shell 0.15 to 0.2, peristome 0.05 to 0.07. + +_Habitat._--North Atlantic, Faeroee Channel, Gulf Stream, surface and at +various depths, John Murray. + + +9. _Challengeron richardsii_, n. sp. (Pl. 99, fig. 8). + +Shell subcircular, lenticular, strongly compressed, with two stout, +divergent, straight spines on the aboral margin (a dorsal and a ventral) +which reach the length of the radius. Peristome slender, semitubular, +slightly curved, about as long as the radius, with three short, divergent, +{1656}terminal teeth. Mouth obliquely truncate. The dorsal odd tooth is +nearly vertical, the two lateral paired teeth almost horizontal. + +_Dimensions._--Diameter of the shell 0.2 to 0.25, length of the spines and +the peristome 0.08 to 0.12. + +_Habitat._--Antarctic Ocean, Station 157, surface, common. + + +10. _Challengeron fergusoni_, n. sp. (Pl. 99, fig. 9). + +Shell isosceles triangular, with three slightly convex edges and two short, +nearly vertically descending spines on the two corners of the aboral +margin. Peristome inversely funnel-shaped, with a deep ventral incision on +the base, and three broad, ovate, triangular teeth. The dorsal odd tooth is +nearly vertical, whilst the two lateral paired teeth are almost horizontal; +therefore the angle between the former and the latter is about a right +angle. + +_Dimensions._--Diameter of the shell 0.2 to 0.3, length of the peristome +0.1. + +_Habitat._--Western Tropical Pacific, Station 224, depth 1850 fathoms. + + +11. _Challengeron tizardi_, John Murray. + + _Challengeria tizardi_, John Murray, 1879, _in litteris_, Narr. Chall. + Exp., vol i. p. 226, pl. A, figs. 7-7_b_. + +Shell nearly equilateral triangular, with concave ventral, convex dorsal +and aboral edges, on the two corners of the latter two opposite horizontal +spines (a dorsal and a ventral). Peristome auriculate and bilobate, with a +deep ventral incision on the base, and three pointed triangular teeth, the +upper margins of which are nearly horizontal. + +_Dimensions._--Diameter of the shell 0.22 to 0.3, length and breadth of the +peristome 0.01 to 0.12. + +_Habitat._--South Atlantic, Stations 332 to 335, depth 1425 to 2200 +fathoms. + + +12. _Challengeron triangulum_, n. sp. (Pl. 99, fig. 10). + +Shell nearly equilateral triangular, with three slightly convex or nearly +straight sides, and two opposite obliquely descending and diverging spines +on the two corners of the aboral margin. Peristome auriculate and bilobate, +with a very thin basal neck and a deep incision on its ventral side; its +distal margin is obliquely truncate, and exhibits an odd ascending dorsal +tooth and two parallel, paired, descending, lateral teeth. + +_Dimensions._--Diameter of the shell 0.2 to 0.3; length and breadth of the +peristome 0.1 to 0.12. + +_Habitat._--North Pacific, Stations 244 to 253, depth 2050 to 3125 fathoms. + + + +Subgenus 3. _Challengeridium_, Haeckel. + +_Definition._--Margin of the shell smooth on the dorsal and the ventral +side, but with three to five or more large spines (or a bunch of spines) on +the aboral side; the middle spine is placed in the main axis, and larger +than the others. + + +{1657}13. _Challengeron bisternum_, n. sp. + +Shell subcircular, lenticular, strongly compressed, with three stout +conical spines on the aboral pole; the middle spine is placed in the main +axis, as long as the radius and three times as long as the two others. +Peristome semitubular, straight, vertical, about as long as the radius, +with three divergent teeth, the middle of which is odd and twice as large +as the two paired lateral teeth. + +_Dimensions._--Diameter of the shell 0.22; length of the peristome 0.1. + +_Habitat._--Indian Ocean, Madagascar (Rabbe), surface. + + +14. _Challengeron heptacanthum_, n. sp. + +Shell ovate, slightly compressed, with a series of five stout, conical, +radial spines on the aboral margin; the middle spine is placed in the main +axis and longer than the radius, twice as long as the two next, and three +times as long as the more distant spines. Peristome short and broad, +collar-shaped, with two large, divergent, straight teeth, each of which is +longer than the shell-radius and bears at its base a large hole. + +_Dimensions._--Length of the shell 0.09 to 0.11, breadth 0.07 to 0.08; +length of the teeth 0.07. + +_Habitat._--Tropical Atlantic, Stations 347, 348, depth 2250 and 2450 +fathoms. + + +15. _Challengeron crosbiei_, n. sp. (Pl. 99, fig. 11). + +Shell ovate, strongly compressed, with a series of seven to nine conical +spines on the aboral margin; the middle spine is placed in the main axis, +as long as the radius, and much larger than the six or eight other spines. +Peristome short and broad, collar-like, with several small spines and two +slender, widely distant, conical teeth, which are half as long as the +shell, and curved towards one another like a pincer, each with a large hole +at its base. + +_Dimensions._--Length of the shell 0.08 to 0.09, breadth 0.06 to 0.07; +length of the two larger teeth 0.04 to 0.05. + +_Habitat._--Central Pacific, Station 270 to 274, depth 2350 to 2925 +fathoms. + + +16. _Challengeron buchanani_, n. sp. (Pl. 99, fig. 12). + +Shell ovate, slightly compressed, with a terminal comb of nine to twelve +conical radial spines, densely crowded on the aboral pole; the middle spine +is placed in the main axis, about half as long as the shell and much larger +than the others. Peristome subconical, semitubular, recurved, half as long +as the shell, with five triangular teeth; the dorsal odd tooth is inclined +backwards, the two parallel pairs of lateral teeth directed ventrally. + +_Dimensions._--Length of the shell 0.15 to 0.18, breadth 0.1 to 0.12; +length of the peristome 0.06 to 0.08. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms. + + + +{1658}Subgenus 4. _Challengerosium_, Haeckel. + +_Definition._--Margin of the shell dentated or serrated, with a continuous +series of numerous short radial spines. + + +17. _Challengeron channeri_, John Murray. + + _Challengeron channeri_, John Murray, 1879, _in litteris_, Narr. Chall. + Exp., vol. i. p. 226, pl. A, fig. 12. + +Shell subcircular, lenticular, strongly compressed, with fourteen to +eighteen slender, straight, radial spines on the margin; the spines are +straight, equidistant, cylindrical, and about as long as the radius of the +shell. Peristome short, with two parallel, vertical, lateral, straight +teeth, which are less than half the length of a spine. + +_Dimensions._--Diameter of the shell 0.14 to 0.17; length of the spines +0.06 to 0.08. + +_Habitat._--North Pacific, Station 231, depth 2250 fathoms. + + +18. _Challengeron moseleyi_, n. sp. (Pl. 99, fig. 14). + +Shell circular, lenticular, strongly compressed, with thirty to forty +slender, straight, equidistant, radial spines on the margin, larger and +smaller spines alternating; the larger spines are about as long as the +radius, the smaller only half as long. Peristome short, tubular, with two +divergent ovate or nearly triangular teeth, a dorsal and a ventral, about +as long as the shorter marginal spines. + +_Dimensions._--Diameter of the shell 0.13 to 0.15; length of the larger +spines 0.06 to 0.07, of the smaller 0.03 to 0.04. + +_Habitat._--North Pacific, Station 244, depth 2900 fathoms. + + +19. _Challengeron bethelli_, John Murray. + + _Challengeron bethelli_, John Murray, 1879, _in litteris_, Narr. Chall. + Exp., vol. i. p. 226, pl. A, fig. 6. + +Shell subcircular, lenticular, strongly compressed, with numerous (twenty +to thirty) short conical spines on the margin (often wanting in the upper +part of the dorsal margin). Peristome with a deep labial incision and two +parallel triangular lateral teeth, the upper margin of which is horizontal. + +_Dimensions._--Diameter of the shell 0.2 to 0.25; length of the spines 0.02 +to 0.03. + +_Habitat._--North Pacific, Stations 238, 241 (off Japan), depth between +2300 and 3950 fathoms. + + +20. _Challengeron bathybium_, n. sp. + +Shell subcircular, lenticular, slightly compressed, with a corona of +numerous (thirty to forty or more) short, conical, radial spines on the +margin. Peristome helmet-shaped, nearly as long as the {1659}radius, with +two widely divergent, conical, curved teeth, a vertical dorsal and a nearly +horizontal ventral tooth. + +_Dimensions._--Diameter of the shell 0.22; length of the peristome 0.1. + +_Habitat._--Western Tropical Pacific, Station 225, depth 4475 fathoms. + + +21. _Challengeron johannis_, n. sp. + +Shell ovate, slightly compressed, with a corona of numerous (forty to sixty +or more) short radial spines on the margin, ten to fifteen of them (in the +aboral half) are pyramidal, and much larger than the others. Peristome +helmet-shaped, about one-third as long as the shell, with a deep bosom and +two widely divergent teeth on the concave upper margin, a forked dorsal and +a conical ventral. + +_Dimensions._--Length of the shell 0.13, breadth 0.1; length of the +peristome 0.04. + +_Habitat._--North Atlantic, Faeroee Channel (Gulf Stream), John Murray. + + +22. _Challengeron carpenterii_, John Murray. + + _Challengeron carpenterii_, John Murray, 1877, _in litteris_, Narr. + Chall. Exp., vol. i. p. 226, pl. A, fig. 8. + +Shell ovate, with a series of twelve to fifteen short, conical, radial +spines on the aboral half of the margin. Peristome slender, semitubular, +nearly as long as the shell, in the upper half forked, with two short +parallel teeth. + +_Dimensions._--Length of the shell 0.13 to 0.18, breadth 0.1 to 0.14; +length of the peristome 0.1 to 0.12. + +_Habitat._--Tropical Atlantic, Stations 347 to 348, depth 2250 to 2450 +fathoms. + + +23. _Challengeron ciliatum_, n. sp. + +Shell ovate, slightly compressed, with numerous (forty to fifty or more) +short and thin, bristle-shaped, radial spines on the margin. Peristome +obliquely truncate, with three curved spines; the dorsal odd spine +subvertical, nearly as long as the radius, and much stronger than the two +parallel, nearly horizontal, lateral spines. + +_Dimensions._--Length of the shell 0.15, breadth 0.11; length of the +peristome 0.1. + +_Habitat._--North Pacific, Station 231, depth 2250 fathoms. + + +24. _Challengeron willemoesii_, n. sp. (Pl. 99, fig. 13). + +Shell broadly-ovate or nearly circular, lenticular, with numerous (fifty to +sixty) short and stout, conical, radial spines on the margin, increasing in +size towards the aboral pole; the spines are alternately larger and +smaller, the largest about half as long as the radius. Peristome +helmet-shaped or half conical, longer than the radius of the shell, with +two pairs of conical, curved, {1660}divergent teeth; the terminal teeth are +the halves of a forked dorsal tooth and diverge laterally; the lower teeth +are nearly horizontal and directed ventrally. + +_Dimensions._--Diameter of the shell 0.13 to 0.15; length of the peristome +0.07 to 0.1. + +_Habitat._--Tropical Pacific, Stations 274 to 276, depth 2350 to 2750 +fathoms. + + +25. _Challengeron wyvillei_, n. sp. (Pl. 99, fig. 15). + +Shell ovate, lenticular, strongly compressed, with numerous (forty to +fifty) short, conical, radial spines on the margin; the spines are larger +on the aboral side and spinulate. Peristome narrow, with two parallel, +lateral, lamellar, forked teeth, about as long as the radius; the upper +branch of the forks is sabre-shaped, obliquely truncate, subvertical, +ciliate, and much broader than the lower nearly horizontal branch, which is +directed towards the ventral side and curved upwards. + +_Dimensions._--Length of the shell 0.12 to 0.16, breadth 0.1 to 0.14; +length of the peristome 0.08 to 0.11. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + + +Subfamily 2. PHARYNGELLIDA, Haeckel. + +_Definition._--#Challengerida# with a pharynx, or an internal prominent +mouth tube. + + + +Genus 696. _Entocannula_,[313] Haeckel, 1879, Sitzungsb. med.-nat. +Gesellsch. Jena, Dec. 12, p. 5. + +_Definition._--#Challengerida# with a pharynx, without teeth on the mouth, +and without marginal spines. + +The genus _Entocannula_ and the two following genera represent together the +subfamily Pharyngellida, differing from the preceding Lithogromida in the +development of a peculiar pharynx, an internal, cylindrical, or +funnel-shaped tube, which is conspicuous, leads from the mouth into the +shell-cavity, and is provided with an inner and an outer opening. The +Pharyngellida are much rarer than the Lithogromida; only ten species have +been observed of the former, fifty of the latter. _Entocannula_ is the +simplest form of the Pharyngellida, having a smooth shell, without aboral +teeth and marginal spines; it differs from _Lithogromia_ only in the +possession of the pharynx. One remarkable species is covered entirely with +extremely thin, flinty hairs, and may represent therefore a peculiar genus, +_Trichogromia_. + + +{1661}1. _Entocannula circularis_, n. sp. + +Shell circular or nearly circular, lenticular, strongly compressed. Pharynx +cylindrical, one-third or one-fourth as broad as the shell, twice as broad +as long, its outer and inner apertures of equal breadth. Surface smooth. + +_Dimensions._--Diameter of the shell 0.20 to 0.32, of the pharynx 0.07 to +0.09. + +_Habitat._--North Pacific, Station 250, depth 3050 fathoms. + + +2. _Entocannula subglobosa_, n. sp. + + _Challengeria bromleyi_, (_partim_), John Murray, 1879, _in schedulis_ + Chall. Coll. + +Shell circular, nearly spherical, slightly compressed. Pharynx +funnel-shaped, truncate, conical, its outer opening twice as broad as the +inner. Surface smooth. + +_Dimensions._--Diameter of the shell 0.25 to 0.28, of the inner mouth 0.05. + +_Habitat._--South Pacific, Station 289, depth 2550 fathoms. + + +3. _Entocannula infundibulum_, n. sp. (Pl. 99, fig. 19). + + _Challengeria bromleyi_ (_partim_), John Murray, 1879, _in litteris_, + Narr. Chall. Exp., vol. i. p. 226, pl. A, fig. 5. + +Shell ovate, truncate at the mouth, slightly compressed. Pharynx +funnel-shaped, its outer aperture two to three times as broad as the inner. +Surface smooth. + +_Dimensions._--Length of the shell 0.22 to 0.28, breadth 0.2 to 0.25; inner +mouth 0.04 to 0.08. + +_Habitat._--South Atlantic, Station 318, depth 2040 fathoms. + + +4. _Entocannula hirsuta_, n. sp. (Pl. 99, fig. 20). + + _Trichogromia hirsuta_, Haeckel, 1881, Manuscript. + +Shell ovate. Pharynx cylindrical, one-fourth as broad as the shell, its +inner and outer apertures of equal breadth. The whole surface of the shell, +and mainly the outer mouth, is densely covered with thin, curved, siliceous +bristles. + +_Dimensions._--Length of the shell 0.27 to 0.36, breadth 0.2 to 0.3; mouth +0.05 to 0.08. + +_Habitat._--North Atlantic, Faeroee Channel (Gulf Stream), John Murray, +depth 600 fathoms. + + + +Genus 697. _Pharyngella_,[314] n. gen. + +_Definition._--#Challengerida# with a pharynx, and with one or more teeth +on the mouth, but without marginal spines. + +The genus _Pharyngella_ differs from the preceding _Entocannula_, its +ancestral form, in the development of one or more teeth on the peristome, +and exhibits therefore the same relation to it that _Challengeria_ bears to +_Lithogromia_. Only a few species of this genus have been observed, all in +the Atlantic. + + +{1662}1. _Pharyngella monoceros_, n. sp. + +Shell ovate, slightly compressed, with a single large tooth on the dorsal +corner of the peristome. The tooth is cylindro-conical, half as long as the +shell, straight or slightly curved, and lies in the main axis of the shell. +Pharynx cylindrical, straight, half as long as the shell-radius. This +species is very similar to _Challengeria tritonis_ (Pl. 99, fig. 5), and to +the common cosmopolitan _Challengeria naresii_, but differs generically +from them in the possession of the pharynx. + +_Dimensions._--Diameter of the shell 0.25 to 0.28; length of the tooth +0.14. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms. + + +2. _Pharyngella gastrula_, n. sp. (Pl. 99, fig. 18). + +Shell ovate. Peristome with two parallel, vertical, straight, pointed +teeth, which are half as long as the shell-radius. Pharynx of the same +length, cylindrical or funnel-shaped, its outer aperture scarcely broader +than the inner. + +_Dimensions._--Length of the shell 0.3 to 36, breadth 0.24 to 0.3; teeth +and pharynx 0.07 to 0.09. + +_Habitat._--North Atlantic, Faeroee Channel (Gulf Stream), John Murray, +depth 600 fathoms. + + +3. _Pharyngella invaginata_, n. sp. + +Shell circular, slightly compressed or nearly spherical. Peristome with two +parallel, vertical, straight, pointed teeth, which are about as long as the +shell-radius. Pharynx of the same length, funnel-shaped; its outer aperture +twice as broad as the inner. + +_Dimensions._--Diameter of the shell 0.2 to 0.22, teeth and pharynx 0.05. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + +4. _Pharyngella gastraea_, n. sp. (Pl. 99, fig. 17). + +Shell broad, ovate or nearly circular, lenticular, strongly compressed. +Peristome with two parallel, pointed teeth, which are nearly as long as the +shell-radius, slightly curved, and obliquely inclined over the mouth. +Pharynx half as long, cylindrical, obliquely descending; its outer and +inner apertures of equal breadth. + +_Dimensions._--Diameter of the shell 0.3 to 0.33, teeth 0.12, pharynx 0.06. + +_Habitat._--South Atlantic, Stations 328 to 334, surface. + + + +Genus 698. _Porcupinia_,[315] Haeckel, 1879, Sitzungsb. med.-nat. +Gesellsch. Jena, Dec. 12, p. 5. + +_Definition._--#Challengerida# with a pharynx, with teeth on the mouth and +marginal spines. + +The genus _Porcupinia_ differs from the preceding _Pharyngella_ in the +development {1663}of marginal spines, and exhibits therefore the same +relation to it that _Challengeron_ bears to _Challengeria_. Only two +species have been observed; the first of these bears, besides the large +marginal spines, numerous flinty bristles on the surface of the shell. + + +1. _Porcupinia aculeata_, n. sp. + +Shell ovate, one and one-third times as long as broad, slightly compressed, +covered with short, bristle-shaped spines over the whole surface, similar +to _Entocannula hirsuta_ (Pl. 99, fig. 20). The keeled margin is armed with +numerous long and stout radial spines, which are alternately larger and +smaller, as in _Challengeron moseleyi_ (Pl. 99, fig. 14); the larger about +as long as the radius, the smaller half as long. Peristome with two +straight, parallel teeth. Pharynx funnel-shaped, half as long as the +radius, its outer aperture twice as broad as the inner. + +_Dimensions._--Length of the shell 0.24, breadth 0.18; peristome 0.05. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + +2. _Porcupinia cordiformis_, n. sp. (Pl. 99, fig. 16). + +Shell heart-shaped, nearly triangular, with a deep, concave bosom at the +broad oral base, and a bunch of five to nine divergent spines at the blunt +aboral apex, the middle spine (in the main axis) larger than the others. +Peristome with two parallel, short, triangular teeth, which are obliquely +inclined over the mouth (their upper convex edge nearly horizontal). +Pharynx cylindrical, short, curved, and obliquely descending. + +_Dimensions._--Diameter of the shell 0.2 to 0.25, of the pharynx 0.05 to +0.08. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + + +Family LXXIX. #MEDUSETTIDA#, n. fam. (Pls. 118-120). + +_Definition._--PHAEODARIA with a simple, ovate, hemispherical or cap-shaped +lattice-shell of peculiar alveolate structure, and with hollow articulate +feet surrounding the widely open mouth. Central capsule excentric, placed +in the aboral half of the shell-cavity. + +The family #Medusettida# represents a peculiar group of remarkable +PHAEODARIA, which are similar to the Challengerida and Tuscarorida in the +general form of the monaxonian shell and its apophyses, but differ from +both families in the strange alveolate structure of the shell and of the +hollow articulate feet surrounding its mouth. All the forms of this family +here described are new, and not a single species was known before the +discoveries of the Challenger. The majority seem to be inhabitants of the +deep-sea, and occur mainly in those places where other families of +PHAEODARIA (Aulacanthida, Aulosphaerida, Coelodendrida) are also well +represented; they are, however, nowhere so common as these latter families. +Their long feet and the small delicate {1664}shell are extremely fragile, +so that complete and well-preserved specimens are rare. Some species are +among the most admirable forms of Radiolaria, and are similar to small +elegant Medusae, _e.g._, _Medusetta_ (Pl. 120, figs. 1-4), _Gazelletta_ +(Pl. 118, fig. 1), and _Gorgonetta_ (Pl. 119). + +The shell of the Medusettida is usually very small and delicate, in +comparison to the long, often exceedingly large, feet, which depend from +the margin of its mouth. From the size and the weight of these feet, we +must suppose that the shell floats in the water in the same position as in +the NASSELLARIA, so that the main axis is vertical, and the open mouth with +the feet on its lower pole. The form of the shell exhibits the same +varieties as the similar umbrella of the Medusae. It is usually more or +less hemispherical, sometimes flatter, cap-shaped, at other times more +highly vaulted, campanulate or ovate. The similarity with the umbrella of a +Medusa is so great, that in many species the large lower opening on the +mouth of the shell is surrounded by a prominent ring or diaphragm, +comparable to the velum of the Craspedotae or Hydromedusae (Pl. 120, figs. +3-4). + +The structure of the shell, which we term shortly "alveolate," is very +remarkable, and seems to be different from that of the other PHAEODARIA. +Its reticulate appearance seems to indicate at first sight the usual +lattice-shell, pierced by numerous very small pores (Pl. 118, figs. 1-3). +But as soon as we make the shell dry, air always enters into its thin +walls, and each apparent pore is found to be a small alveole or a separate +compartment, which contains a small bubble of air (Pl. 120, figs. 11, 16). +The thin wall of the shell is therefore double, composed of two parallel, +very thin lamellae of silica, which are little distant from one another, +and are connected by a network of small rods or septa. This network is +rarely regular, with square meshes (Pl. 118, fig. 3), or with hexagonal or +triangular meshes (Pl. 116, fig. 2); it is usually irregular, with +polygonal meshes (Pl. 120, figs. 11-16). The size of the meshes or alveoles +is usually smallest on the aboral apex of the shell, and increases +gradually towards the mouth. The largest alveoles are around the mouth, on +the velum-shaped peristome, and here the marginal alveoles of the shell +pass directly over into the separate alveoles or hollow compartments of the +articulate feet (Pl. 118, fig. 1). Probably each alveole is a separate +compartment, filled up by jelly, and has a small opening or pore on its +inside; this pore is very distinct in the marginal alveoles of some larger +species (Pl. 116, fig. 1_a_; Pl. 120, fig. 14), but I have not been able to +recognise it everywhere. Moreover, it often happens that the alveoles are +apparently completely closed. In some smaller species the alveolate +structure seems to be present only in the peripheral part of the shell, +whilst the central part is solid. + +The outer convex surface of the shell is usually smooth, sometimes +papillate (Pl. 116, fig. 1), at other times studded with small, conical, +radial spines (Pl. 118, fig. 1; Pl. 120, figs. 4-11). Prolonged cylindrical +spines or tubes are rarely {1665}scattered over the surface (Pl. 116, figs. +1, 2). In some genera a long vertical or oblique spine is developed from +the apex of the shell, and is comparable to the "apical horn" of the +NASSELLARIA (Pl. 118, figs. 2, 3; Pl. 120, figs. 1-4). + +The mouth of the shell, or the large opening on the lower pole of its +vertical main axis, is usually widely open, circular or polygonal, more +rarely constricted. In many species the peristome is broadened and its +margin developed in the form of a horizontal diaphragm, which constricts +the entrance into the shell-cavity, and is comparable to the velum of the +Hydromedusae (Pl. 120, figs. 1-4). Sometimes the margin of the velum is +fringed and bears numerous small dependent filaments of silica, comparable +to the marginal tentacles of many Medusae (Pl. 118, figs. 1, 3; Pl. 120, +fig. 16). Rarely the mouth is strongly constricted and prolonged into a +narrow, long, cylindrical tube, comparable to a proboscis; its opening is +usually fringed (Pl. 116, figs. 1, 2). + +The hollow articulate feet, or the large radial apophyses of the peristome, +are the most remarkable organs of the Medusettida, and occur in the same +form in no other family of Radiolaria. Their number is variable from three +to twelve or more, and is here employed for the distinction of genera, as +it is rather constant; the most frequent number is four (_Medusetta_) or +six (_Gazelletta_). The feet are usually cylindrical, much longer than the +shell, and more or less curved; more rarely they are straight or slightly +compressed. They are always articulate, and divided by numerous transverse +parallel septa into hollow compartments or alveoles; the transversely +striated appearance of the feet is brought about by these septa. The +alveoles have usually the form of short discoidal cylinders, and are +broader than long (Pl. 120, figs. 5-13); rarely they are longer than broad +(fig. 15). The septa between the alveoles are always perforated by a small +opening and usually this opening is prolonged into a shorter or longer +tubule, comparable to the siphuncle in the septa of the chambered shells of +Cephalopoda; as in these latter, the succeeding siphons are arranged in a +continuous series, which lies either in the axis of the foot or parallel to +it (Pl. 120, figs. 8, 13, 15). The siphons are directed towards the distal +end of the foot, so that, _e.g._, the siphon which arises from the septum +between the ninth and tenth alveole, projects into the cavity of the +latter. The communicating cavities of all the alveoles are filled up by +jelly. In the dry shells, which are cleaned by hot mineral acids or by +fire, and in which, therefore, the jelly is destroyed, the cavities become +easily filled by air-bubbles (Pl. 120, figs. 8, 11, 15). Whilst the +alveoles of each foot always form a long simple series, this series becomes +doubled on the base of the larger feet, where they are broadened, and pass +over into the compartments of the peristome (Pl. 122, figs. 10, 11, 14). +The terminal alveole of each foot is closed. + +The feet of the Medusettida are rarely quite simple and smooth (Pl. 120, +figs. 1, 5, 7, 10, &c.). Usually they are armed with numerous spines or +with elegant pencils of spathillae. These secondary appendages or branches +are also hollow, with a {1666}thin wall of silex; but they seem usually not +to communicate with the alveoles of the foot directly; the cavities of the +foot and its appendages are separated by a thin, solid septum. In +_Medusetta_ the convex outer edge of each curved foot is studded with a +series of simple alveolate branches (Pl. 120, figs. 2-4). In _Gazelletta_, +the feet are usually armed with verticillate or alternate spines, which are +either simple or branched (Pl. 120, figs. 11-15); sometimes each branch is +elegantly arborescent (Pl. 118, fig. 1). Sometimes the distal end of each +branch is armed with a spathilla or a coronet of recurved teeth. The +branches attain their highest development in the admirable _Gorgonetta_ +(Pl. 119). The twelve feet of this most interesting genus are +differentiated into two different and alternating groups, six descending +and six ascending. The six upper or ascending feet are arborescent, and +each branch is armed at the distal end with a spathilla (figs. 1, 2). The +six lower or descending feet are covered with most elegant arborescent +pencils or anchor-bearing trees; each terminal branch of a tree is armed +with two spathillae, a smaller terminal and a larger below it (figs. 3, 4). +The distal ends of the feet are rarely simple, usually they are forked or +branched, or armed with peculiar spathillae; and sometimes these terminal +branches are very large (Pls. 118, 119). + +The _central capsule_ of the Medusettida is usually subspherical or +somewhat lenticular, and hidden in the aboral or upper part of the +shell-cavity, whilst its oral or lower part is filled up by the phaeodium +(Pl. 120, figs. 2, 9, 10, 11). Sometimes the phaeodium is very large and +prominent at the aperture of the mouth (Pl. 118, figs. 2, 3; Pl. 119, fig. +1). The nucleus is usually ellipsoidal, half as large as the central +capsule, and includes numerous nucleoli. The membrane of the central +capsule seems in all Medusettida to possess only one opening, the astropyle +or main-opening with a radiate operculum and proboscis, placed at the lower +or oral pole (Pl. 120, fig. 2). I have never been able to observe any +secondary opening or parapyle. The free space between the shell wall and +the capsule is filled up by the calymma, which also includes the phaeodium. +The jelly of the calymma is probably in direct continuity with the jelly +which fills up the alveoles of the shell-wall and of the articulate feet. + +_Synopsis of the Genera of Medusettida._ + + I. Subfamily Euphysettida. { Three equal feet, 699. _Cortinetta_. + Peristome of the shell with { + a corona of three or four { Four equal feet, 700. _Medusetta_. + feet. Apex of the shell { + (usually) with an apical { One large and three + horn. { small feet, 701. _Euphysetta_. + + { Six descending feet, 702. _Gazelletta_. + { + II. Subfamily Gazellettida. { Six descending and six + Peristome of the shell with { ascending alternating + six to twelve or more feet. { feet, 703. _Gorgonetta_. + Apex of the shell (usually) { + without apical horn. { Numerous (ten to twenty + { or more) descending + { feet, 704. _Polypetta_. + + + +{1667}Genus 699. _Cortinetta_,[316] n. gen. + +_Definition._--#Medusettida# with three articulate feet on the peristome. + +The genus Cortinetta comprises Medusettida which exhibit the minimum number +of feet, three, and which therefore may be compared to the tripodal +NASSELLARIA (_Cortina_, _Cortiniscus_, _Tripodiscus_, &c.). This similarity +is the greater, as in the few observed species an apical horn is developed +(as also in the following genus). The three feet are in the two species +observed of equal size and similar form, and equidistant, so that they +cannot be distinguished as an odd caudal and two paired lateral feet, as in +the similar NASSELLARIA. + + +1. _Cortinetta tripodiscus_, n. sp. (Pl. 117, fig. 7). + +Shell campanulate, covered with numerous curved ascending bristles, with a +prominent annular velum on the peristome, similar to that of _Medusetta +craspedota_. (Pl. 120, fig. 4). Feet equal, widely divergent and +equidistant, somewhat longer than the shell, slightly curved, and covered +on their convex outer edge with a series of short lateral branches, the +three ramules of which bear a spathilla. Apical horn conical, straight, +about as long as the shell, also covered with curved bristles. + +_Dimensions._--Length of the shell 0.14, breadth 0.11; length of the feet +0.16, of the apical horn 0.11. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +2. _Cortinetta cortiniscus_, n. sp. + +Shell campanulate, subspherical, thorny, with a prominent annular velum on +the peristome. Feet equal, very large, widely divergent, about three times +as long as the shell and studded with arborescent branches, similar to +those of _Gazelletta drymonema_ (Pl. 118, fig. 1). Apical horn slender, +conical, straight, thorny, twice as long as the shell. + +_Dimensions._--Length of the shell 0.18, breadth 0.16; length of the feet +0.5 to 0.6, of the apical horn 0.33. + +_Habitat._--Central Pacific, Station 274, depth 2750 fathoms. + + + +Genus 700. _Medusetta_,[317] n. gen. + +_Definition._--#Medusettida# with four equidistant articulate feet of equal +size on the peristome. + +The genus _Medusetta_ comprises those forms of the family which bear on the +peristome four equal radial feet, and therefore exhibit a striking +similarity to many {1668}small Medusae (_e.g._, _Codonium_, _Tiara_, +_Sarsia_, &c.). This similarity is the greater, as usually the four feet +are elegantly curved and the entrance in the shell-cavity partly closed by +a marginal diaphragm, comparable to the velum of the Craspedotae or +Hydromedusae. In all the species observed the apex of the shell bears a +slender vertical or curved spine, comparable to the apical horn of the +NASSELLARIA. In most species the feet bear on their convex outside a series +of teeth or branches, which are also alveolate. + + +1. _Medusetta codonium_, n. sp. (Pl. 120, fig. 1). + +Shell ovate, smooth, twice as broad as the constricted mouth. Apical horn +about as long as the shell, nearly straight, smooth. Feet cylindrical, +smooth, irregularly curved, about as long as the shell. + +_Dimensions._--Length of the shell 0.08, breadth 0.05. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + +2. _Medusetta tiara_, n. sp. + +Shell campanulate, smooth, about as long as broad, and three times as broad +as the constricted mouth, which is surrounded by a horizontal broad ring, +like the velum of a Hydromedusa. Apical horn conical, straight, half as +long as the shell. Feet divergent, irregularly curved, twice as long as the +shell. + +_Dimensions._--Length of the shell 0.07, breadth 0.06. + +_Habitat._--North Atlantic (Faeroee Channel), John Murray, surface. + + +3. _Medusetta minima_, n. sp. + +Shell slenderly ovate, smooth, about twice as long as broad, twice as broad +as the constricted mouth. Apical horn straight, vertical, of the same +length. Feet somewhat longer, very thin, slightly curved at the base, in +the distal half nearly parallel and descending vertically. + +_Dimensions._--Length of the shell 0.06, breadth 0.03. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +4. _Medusetta quadrigata_, n. sp. (Pl. 120, fig. 2). + +Shell ovate, campanulate, smooth, little broader than the wide open mouth. +Apical horn longer than the shell, more or less curved, smooth. Feet +cylindrical, about as long as the shell, strongly curved and somewhat +spirally revoluted, with a series of short curved teeth on the abaxial +margin. + +_Dimensions._--Length of the shell 0.07 to 0.09, breadth 0.04 to 0.06. + +_Habitat._--North Pacific (off Japan), Stations 231 to 237, surface. + + +{1669}5. _Medusetta tetranema_, n. sp. (Pl. 120, fig. 3). + +Shell campanulate, conical, smooth, nearly twice as broad as the +constricted mouth, without prominent velum. Apical horn somewhat shorter, +straight, conical, thorny. Feet strongly curved inwards, convergent, twice +as long as the shell, each with four to six strong, ascending, alveolate +branches on the abaxial margin. + +_Dimensions._--Length of the shell 0.07 to 0.09, breadth 0.05 to 0.07. + +_Habitat._--Tropical Atlantic, Station 352, surface. + + +6. _Medusetta spiralis_, n. sp. + +Shell hemispherical, thorny, with wide open mouth. Apical horn straight, +vertical, thorny, twice as long as the shell; feet cylindrical, three times +as long as the shell, spirally convoluted around the vertical axis of the +shell, with a series of recurved teeth on the abaxial margin. + +_Dimensions._--Length of the shell 0.05, breadth 0.08. + +_Habitat._--Central Pacific, Stations 271 to 272, surface. + + +7. _Medusetta craspedota_, n. sp. (Pl. 120, fig. 4). + +Shell campanulate or nearly spherical, spiny, twice as broad as the +constricted mouth, which is surrounded by a funnel-shaped truncate velum. +Apical horn conical, straight, spiny, half as long as the shell. Feet +strongly curved, longer than the shell, with a series of short conical +spines on the abaxial side. + +_Dimensions._--Length of the shell 0.06, breadth 0.06. + +_Habitat._--North Pacific, Station 239, surface. + + + +Genus 701. _Euphysetta_,[318] n. gen. + +_Definition._--#Medusettida# with four articulate feet on the peristome, +one odd very large, and three small or rudimentary feet. + +The genus _Euphysetta_ agrees with the preceding _Medusetta_ in the +possession of four articulate feet; but whilst these in the latter are of +equal size and similar shape, in the former a single odd foot only is +developed, and very large, whilst the three others are rudimentary and very +small. _Euphysetta_ exhibits therefore the same relation to _Medusetta_ +that the Euphysidae (_Euphysa_, _Steenstrupia_, &c.) bear to the Sarsiadae +(_Codonium_, _Sarsia_), among the Hydromedusae (compare my System der +Medusen, 1879, vol. i. p. 12). + + +{1670}1. _Euphysetta staurocodon_, n. sp. (Pl. 118, fig. 2). + +Shell ovate, nearly as broad as long, smooth, with an oblique, slender, +conical, apical horn of the same length. The larger odd foot cylindrical, +curved, somewhat longer than the shell, with three diverging branches at +the distal end. The three smaller feet very short, representing the form of +a regular rectangular cross. + +_Dimensions._--Length of the shell 0.15, breadth 0.14. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms. + + +2. _Euphysetta hybocodon_, n. sp. + +Shell ovate, one and one-third times as long as broad, smooth, with an +oblique, stout, conical horn of half the length. The larger odd foot +cylindrical, curved, twice as long as the shell, with a few pairs of short +lateral branches and forked distal end. The three smaller feet half as long +as the shell, thorny. + +_Dimensions._--Length of the shell 0.16, breadth 0.12. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + +3. _Euphysetta amphicodon_, n. sp. (Pl. 118, fig. 3). + +Shell subspherical, smooth, with a short, oblique, conical, apical horn. +The larger odd foot cylindrical, nearly straight, as long as the shell, +with a few short lateral branches, at the distal end forked. The three +smaller feet were in one specimen observed forked, in another (the specimen +figured) replaced by nine small thorns. + +_Dimensions._--Length of the shell 0.11, breadth 0.13. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + + +Genus 702. _Gazelletta_,[319] John Murray, 1876 (_in litteris_). + +_Definition._--#Medusettida# with six articulate feet on the peristome. + +The genus _Gazelletta_ is by far the most common of all Medusettida, and +some species seem to be widely distributed, or even cosmopolitan. The +number of species, too, is in this genus much larger than in all the other +genera of this family. It differs from the latter in the possession of six +feet, which number is very constant in the majority of species; in some +species, however, single specimens are not rarely found which possess five +or seven feet instead of six. Usually the six feet are rather regularly +formed and disposed, and diverge downwards; but sometimes there is more or +less {1671}irregularity in their shape and arrangement. In the majority of +species the feet are very long, curved, and armed in a very various manner, +so that four subgenera may be distinguished, according to the armatures. + + + +Subgenus 1. _Gazellarium_, Haeckel. + +_Definition._--Feet simple, smooth, without spines and without terminal +branches. + + +1. _Gazelletta hexanema_, n. sp. (Pl. 120, fig. 5). + +Shell hemispherical, smooth. Feet very long, cylindrical, straight, smooth, +widely divergent, without terminal branches. + +_Dimensions._--Length of the shell 0.03 to 0.04, breadth 0.06 to 0.07; +length of the feet 0.1 to 0.2. + +_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Indian, Pacific, +surface. + + +2. _Gazelletta macronema_, n. sp. (Pl. 120, figs. 7, 8). + +Shell hemispherical, smooth. Feet very long, cylindrical, smooth, in the +basal part horizontally expanded, in the distal part strongly curved +downwards, without terminal branches. + +_Dimensions._--Diameter of the shell 0.1 to 0.12, length of the feet 1.2 to +1.6. + +_Habitat._--Central Pacific, Stations 270 to 274, surface. + + +3. _Gazelletta orthonema_, n. sp. (Pl. 120, fig. 10). + +Shell hat-shaped, thorny. Feet cylindrical, straight, smooth, widely +divergent, without terminal branches. + +_Dimensions._--Diameter of the shell 0.12 to 0.16, length of the feet 0.3 +to 0.5. + +_Habitat._--Central Pacific, Stations 270 to 274, surface. + + +4. _Gazelletta cyrtonema_, n. sp. (Pl. 120, fig. 9). + +Shell hat-shaped, thorny. Feet cylindrical, smooth, widely diverging at the +base, strongly curved and convergent in the distal part, often +semicircular, without terminal branches. + +_Dimensions._--Diameter of the shell 0.11 to 0.13, length of the feet 0.4 +to 0.6. + +_Habitat._--North Atlantic, Station 354, Canary Islands, surface. + + + +Subgenus 2. _Gazellidium_, Haeckel. + +_Definition._--Feet smooth, without lateral spines, but branched at the +distal end, or with a bunch of terminal spines. + + +{1672}5. _Gazelletta furcata_, n. sp. + +Shell flat, cap-shaped, smooth. Feet cylindrical, nearly straight, at the +distal end forked, with two divergent, spinulate, terminal branches. + +_Dimensions._--Length of the shell 0.12, breadth 0.3; length of the feet +0.6 to 0.8. + +_Habitat._--Western Tropical Pacific, Station 224, surface. + + +6. _Gazelletta bifurca_, n. sp. (Pl. 120, fig. 6). + +Shell cap-shaped, thorny. Feet nearly straight, widely divergent, +cylindrical, smooth, at the distal end twice forked, with four divergent, +terminal branches, each of which bears a spathillum with six to eight +recurved teeth (sometimes, as in the specimen figured, five or six terminal +branches instead of four). + +_Dimensions._--Diameter of the shell 0.1, length of the feet 0.3 to 0.4. + +_Habitat._--South Pacific, Station 288, surface. + + +7. _Gazelletta penicillata_, n. sp. + +Shell campanulate, spiny. Feet cylindrical, strongly curved, smooth, with a +bunch of twelve to twenty or more curved spines at the distal end. + +_Dimensions._--Diameter of the shell 0.08, length of the feet 0.6. + +_Habitat._--Central Pacific, Station 266, surface. + + + +Subgenus 3. _Gazellonium_, Haeckel. + +_Definition._--Feet spiny, armed with simple or branched lateral spines, +and with terminal branches of the same shape. + + +8. _Gazelletta pectinata_, n. sp. + +Shell flat, cap-shaped, thorny, three times as broad as high. Feet straight +or slightly curved, cylindrical, widely divergent, with four longitudinal +rows of short and simple conical spines, which are directed towards the +distal end, and about as long as a single joint of the foot. + +_Dimensions._--Length of the shell 0.16, breadth 0.5; length of the feet +1.5 to 2.0, breadth 0.03 to 0.05. + +_Habitat._--North Atlantic, Faeroee Channel (John Murray), Hebrides +(Moebius). + + +9. _Gazelletta pinnata_, n. sp. + +Shell hat-shaped, thorny. Feet cylindrical, strongly curved, pinnate, with +two opposite longitudinal rows of simple conical spines, which are slightly +curved, directed towards the distal end and opposed in pairs on about each +third or fourth joint. + +_Dimensions._--Diameter of the shell 0.3, length of the feet 1.2 to 1.5. + +_Habitat._--South Atlantic, Station 325, depth 2650 fathoms. + + +{1673}10. _Gazelletta studeri_, n. sp. (Pl. 120, fig. 15). + +Shell flat, cap-shaped, thorny. Feet widely divergent, nearly straight and +horizontally expanded, with two alternate longitudinal rows of lateral +spines, which arise perpendicularly from the foot, are simple, conical, +slightly curved, and alternate on the succeeding joints. Ends of the feet +constricted, with four to six spines in one row. Dedicated to Professor +Studer. + +_Dimensions._--Diameter of the shell 0.15, length of the feet 0.6 to 0.8. + +_Habitat._--South Atlantic (east of Patagonia), Station 318, surface. + + +11. _Gazelletta schleinitzii_, n. sp. (Pl. 120, figs. 11, 12). + +Shell hat-shaped, thorny. Feet cylindrical, nearly straight and +horizontally expanded, with four longitudinal rows of equal lateral spines, +which arise perpendicularly from the foot and bear at the end three short +divergent teeth. The end of the arms bears three forked spines. I name this +elegant species in honour of Captain Schleinitz, commander of the German +ship "Gazelle," who conducted the deep-sea soundings during the years 1874 +to 1876. + +_Dimensions._--Diameter of the shell 0.12, length of the feet 0.6 to 0.8. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + +12. _Gazelletta trispathilla_, n. sp. (Pl. 120, fig. 13). + +Shell flat, cap-shaped, smooth. Feet cylindrical, nearly straight, widely +divergent, with longitudinal rows of alternate spines, which arise +perpendicularly from the foot and bear at the end three short divergent +branches, each with a spathilla of six short teeth. + +_Dimensions._--Diameter of the shell 0.2 to 0.25, length of the feet 1.2 to +1.5. + +_Habitat._--North Pacific, Station 235 to 238, surface. + + +13. _Gazelletta robusta_, n. sp. (Pl. 120, fig. 14). + +Shell flat, cap-shaped, thorny. Feet cylindrical, very stout, slightly +curved, covered with short irregularly branched spines; their ends with a +bunch of similar spines. + +_Dimensions._--Diameter of the shell 0.6, length of the feet 2.5 to 3.3. + +_Habitat._--Central Pacific, Stations 263 to 274, surface. + + + +Subgenus 4. _Gazellusium_, Haeckel. + +_Definition._--Feet spiny, armed with simple or branched lateral spines, +and with larger terminal branches of a different shape. + + +{1674}14. _Gazelletta dendronema_, n. sp. (Pl. 120, fig. 16). + +Shell hemispherical, thorny, with a broad, alveolate velum which bears +irregular hollow thorns on the inside and on the free margin (fig. 16). +Feet divergent, irregularly curved, with scattered arborescent lateral +spines, which are irregularly branched, and bear at the distal end of each +branch a small spathilla with four to six teeth. The distal ends of the +feet are dichotomously branched, with stouter simple fork-branches. + +_Dimensions._--Length of the shell 0.17, breadth 0.36; length of the feet +0.5 to 0.7. + +_Habitat._--North Pacific, Station 252, surface. + + +15. _Gazelletta melusina_, n. sp. (Pl. 118, fig. 1). + +Shell campanulate, spiny. Feet divergent, strongly curved, with scattered +arborescent lateral spines, which are richly and dichotomously branched, +with thin, simple, terminal branches. The distal ends of the feet bear +three or four much larger and stouter branches, which are again +dichotomously branched. + +_Dimensions._--Length of the shell 0.2, breadth 0.15; length of the feet +0.5 to 0.8. + +_Habitat._--South Pacific, Station 293, depth 2025 fathoms. + + + +Genus 703. _Gorgonetta_,[320] n. gen. + +_Definition._--#Medusettida# with twelve articulate feet on the peristome, +six ascending and six alternate descending. + +The genus _Gorgonetta_ is the most highly developed of all hitherto +observed Medusettida, and belongs to the most remarkable forms of +Radiolaria. Its general shape is very similar to that of a larva of a +_Geryonia_ or _Carmarina_, in which six interradial larval tentacles are +directed upwards, six alternating perradial permanent tentacles downwards. +The six ascending feet are in all the four species observed smaller, more +or less branched, and armed with spathillae. The six descending feet are +much larger and covered with very elegant pencils, the single threads of +which bear a double spathilla. The distal ends of the feet are forked or +branched. + + +1. _Gorgonetta mirabilis_, n. sp. (Pl. 119, figs. 1-4). + +Shell cap-shaped, flatly vaulted, or nearly hemispherical, about twice as +broad as long, with smooth surface. Six ascending feet widely divergent, +about twice as long as the breadth of the shell, nearly straight, +arborescent, with numerous curved branches, each of which bears at the +distal end a spathilla with four to six short recurved teeth (fig. 2). Six +descending feet about twice as {1675}long as the six alternate ascending, +nearly straight, covered with numerous elegant pencils. Each pencil is +richly branched, with fifty to one hundred or more thread-like ramules, and +each terminal ramule has two cruciate spathillae, a larger proximal and a +smaller distal (figs. 3, 4); the four recurved anchor-teeth of the proximal +spathilla are twice as large as those of the distal. The distal end of each +descending foot bears three or four very stout terminal branches, each of +which is about as long as the shell and again trifurcate at the distal end. + +_Dimensions._--Length of the shell 0.2 to 0.3, breadth 0.4 to 0.5. + +_Habitat._--Tropical Atlantic, Stations 346 to 348, surface. + + +2. _Gorgonetta geryonia_, n. sp. + +Shell hemispherical, twice as broad as long, with short scattered thorns on +the surface. Twelve feet of similar shape to those in the preceding +species, but differing in the following characters:--the six ascending feet +are much smaller, about as long as the breadth of the shell, and each bears +only six to twelve short branches; the six descending feet are about three +times as long as the shell, more or less curved; their pencils much +smaller, and the two spathillae of each pencil-thread bear five +anchor-teeth. The distal ends are more richly and irregularly branched. + +_Dimensions._--Length of the shell 0.4, breadth 0.7. + +_Habitat._--Indian Ocean (Cocos Islands), Rabbe, surface. + + +3. _Gorgonetta carmarina_, n. sp. + +Shell flat, cap-shaped, three times as broad as long. Twelve feet similar +in shape to those of the two preceding species, but more irregular in form +and arrangement, and differing in the following characters:--the six +ascending feet are nearly horizontally expanded, one and a half times as +long as the breadth of the shell, with few short branches, each of which +bears a spathilla with six recurved anchor-teeth. The six descending feet +are about five times as long as the shell, irregularly curved, studded with +numerous small pencils, each thread of which bears a double spathilla with +six teeth. The distal ends are irregularly branched. + +_Dimensions._--Length of the shell 0.2, breadth 0.7. + +_Habitat._--South Pacific, Station 318, depth 2040 fathoms. + + +4. _Gorgonetta bisenaria_, n. sp. + +Shell campanulate, similar to that of _Gazelletta melusina_ (Pl. 118, fig. +1), with smooth surface. Six ascending feet about as long as the shell, +nearly straight, similar to those of _Gorgonetta mirabilis_ (Pl. 119, fig. +1). Six descending feet also similar to those of the latter, but shorter, +about twice as long as the shell, strongly curved, studded with numerous +small pencils, each thread of which has a double spathilla with three +teeth. The distal end of each foot bears a whorl of six to eight irregular +forked branches. + +_Dimensions._--Length of the shell 0.5, breadth 0.4. + +_Habitat._--Central Pacific, Station 263, surface. + + + +{1676}Genus 704. _Polypetta_,[321] n. gen. + +_Definition._--#Medusettida# with numerous (ten to twenty or more) +articulate feet. + +The genus _Polypetta_ comprises those Medusettida in which the number of +feet is very large and not limited, usually twenty to thirty or more. The +few specimens of this genus that have been observed are rather different; +and it may be that only the two first species described in the following +lines are true Medusettida; they possess the usual distinctly alveolate +feet, and are derived from the similar _Medusetta_ or _Gazelletta_ simply +by multiplication of the feet. The two other species, however (figured in +Pl. 116, figs. 1, 2, as _Porospathis_), belong perhaps to another family of +PHAEODARIA (Castanellida?); their shell-structure is peculiar and their +feet not distinctly alveolate; they may therefore represent a peculiar +genus _Porospathis_ (Haeckel, Sitzungsb. med.-nat. Gesellsch. Jena, Dec. +12, 1879, p. 5). + + +1. _Polypetta polynema_, n. sp. + +Shell campanulate, thorny, about as long as broad, with slightly +constricted mouth, similar to that of _Gazelletta orthonema_ (Pl. 120, fig. +10). Shell-wall hollow, with irregular polygonal alveoles. Peristome with a +corona of eighteen divergent, curved, cylindrical feet of unequal size; six +larger primary on the margin of the shell, the other twelve secondary, +between the former, somewhat above the margins at different heights. The +feet are two to three times as long as the shell, irregularly curved and +distinctly alveolate, without appendages. + +_Dimensions._--Length of the shell 0.12, breadth 0.11. + +_Habitat._--Central Pacific, Station 266, surface. + + +2. _Polypetta alveolata_, n. sp. + +Shell campanulate, thorny, about as long as broad, very similar to that of +_Medusetta craspedota_ (Pl. 120, fig. 4). Shell-wall hollow, with +subregular hexagonal alveoles. Peristome prolonged into a short +funnel-shaped proboscis, twice as long as the similar velum of the latter. +The velum is surrounded by a corona of eight larger and eight to twelve +smaller feet; the larger are about as long as the shell, divergent, +irregularly curved, thorny, and distinctly alveolate; the smaller feet are +scattered above the latter and form an immediate transition to the small +spines of the shell-surface. + +_Dimensions._--Length of the shell 0.08, breadth 0.09. + +_Habitat._--South Pacific, Station 284, surface. + + +{1677}3. _Polypetta tabulata_, n. sp. (Pl. 116, figs. 2, 2_a_, 2_b_). + + _Porospathis tabulata_, Haeckel, 1879, Sitzungsb. med.-nat. Gesellsch. + Jena, Dec. 12. + +Shell subspherical, with elegantly panelled or tabulate surface, composed +of small triangular plates, which are separated by a network of prominent +crests; at each nodal point of the network a small conical thorn arises +(figs. 2_a_, 2_b_). Each triangular plate seems to contain a hollow +alveole, which opens into the shell-cavity (?). On the surface of the shell +are scattered numerous (thirty to forty or more), cylindrical, hollow, +radial spines, which are straight or slightly curved, not distinctly +alveolate, and increase in size towards the mouth. The aboral spines are +scarcely one-third as long as the radius of the shell, whilst the oral +spines are three times as long as its diameter. The proboscis of the +constricted mouth is a hollow cylinder, longer than the shell-radius, and +armed with a corona of fifteen to twenty slender bristle-shaped teeth. The +position of this singular species in this family is doubtful. + +_Dimensions._--Diameter of the shell 0.1 to 0.11, length of the peristome +0.07, breadth 0.02. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +4. _Polypetta mammillata_, n. sp. (Pl. 116, figs. 1, 1_a_). + + _Porospathis mammillata_, Haeckel, 1879, Sitzungsb. med.-nat., Gesellsch. + Jena, Dec. 12. + +Shell subspherical, densely covered with numerous mammiliform hollow +papillae, between which are scattered single longer, hollow, radial spines; +these are irregularly curved, cylindrical, without distinct alveoles; the +twelve longest are two to three times as long as the shell, divergent in +the oral direction, and surround the base of the peristome in two irregular +alternate circles, each with six spines. The hollow papillae of the +surface, between which are placed numerous circular pores (or dimples?), +open into the shell-cavity by a small pore (fig. 1_a_); they are perhaps +reduced radial spines. The constricted peristome is conical and prolonged +into an inversely conical proboscis, which is about as long as the radius +of the shell; its dilated mouth is surrounded by a corona of slender, +divergent, bristle-shaped teeth. The position of this species in the family +Medusettida is doubtful; perhaps it is more closely allied to the +Castanellida. + +_Dimensions._--Diameter of the shell 0.12; length of the proboscis 0.08, +breadth 0.03; length of the shorter spines 0.1, of the longest spines 0.3. + +_Habitat._--North Pacific, Station 252, surface. + + + +Family LXXX. #CASTANELLIDA#, Haeckel, 1879 (Pl. 113). + + _Castanellida_, Haeckel, 1879, Sitzungsb. med.-nat. Gesellsch. Jena, Dec. + 12, p. 5. + +_Definition._--PHAEODARIA with a spherical or subspherical shell, +exhibiting ordinary lattice-work, with circular or roundish pores. Radial +spines without circles of basal pores. Mouth of the shell large, usually +circular and armed with teeth. Central capsule excentric, placed in the +aboral half of the shell-cavity. + +{1678}The family #Castanellida# represents a common and widely distributed +group of PHAEODARIA, which posses a very simple and uniform shell, viz., a +simple lattice-sphere with radial spines and one simple mouth. It may +therefore be easily confounded with the Coscinommida, or those +#Sphaeroidea# in which the shell is also a simple lattice-sphere armed with +radial spines (_Astrosphaerida simplicia_, p. 209). Indeed the shell of +both groups is very similar, and differs in one important point only; the +Castanellida constantly possess one larger opening in the shell-wall, the +shell-mouth, which is either smooth or armed with a corona of teeth; in the +Coscinommida, however, such a mouth is never present. The living specimens +of both groups, and those shells in which the soft body is preserved, are +very easily distinguished, since the shell encloses in the Coscinommida the +central capsule and the transparent calymma only, whilst the latter, +besides, in the Castanellida contains a voluminous dark brown or green mass +of phaeodella, the characteristic phaeodium. A closer examination of the +central capsule reveals in all Castanellida the typical operculum, the +astropyle, with the proboscis of the PHAEODARIA, which is never present in +any #Sphaeroidea#. + +The Castanellida are easily distinguished also from those similar +PHAEODARIA in which the shell is also a lattice-sphere; the lattice-work is +constantly quite simple, as in the similar Coscinommida, never composed of +separated tangential pieces (as in the Aulosphaerida), or of porcellanous +structure, with basal circles of pores (as in the Circoporida), or of +diatomaceous structure (as in the Challengerida). The gigantic +Orosphaerida, which also in part posses a simple lattice-sphere, differ +from the Castanellida in the absence of the peculiar shell-mouth. + +Though the Castanellida belong to the most common PHAEODARIA, and though +the number of individuals, floating on the surface of the tropical seas, is +extraordinarily great, their variety of forms is very small; the six genera +distinguished in the following system differ only in very slight +characters, and the majority of the species are very similar, and often +hardly distinguishable. The seven species figured in Pl. 113 exhibit the +most striking differences which I could distinguish among all the species +observed. The shell usually has the characteristic appearance of a +chestnut, a sphere covered with very numerous short radial spines or +bristles. In the majority of species a certain number of longer thin radial +spines is scattered over the surface; these are usually simple, rarely +branched. The mouth of the shell, corresponding to the proboscis of the +central capsule, and placed in the same radius, is either a quite simple +larger opening with a smooth margin (figs. 3, 5, 7) or is armed with a +corona of teeth (figs. 1, 6). + +The size of the shell varies between 0.2 and 0.8 mm., and is usually +between 0.3 and 0.5 mm. Its form is in the majority of species a +geometrical sphere; rarely it is somewhat irregular, slightly ellipsoidal +(prolonged in the axis of the mouth and proboscis), or polyhedral (by +conical protuberances from the bases of the radial spines). {1679}The ideal +fundamental form of the shell, however, is constantly monaxonian, since the +place of the shell-mouth and of the proboscis of the capsule (both lying in +one axis of the sphere), causes a principal axis to be different from all +others. The longer radial spines, quite variable in number and disposition, +are never arranged regularly or symmetrically, and therefore determine no +constant axes. + +The lattice-work of the spherical shell offers also but slight differences. +It is usually more or less irregular, with circular or subcircular pores of +unequal sizes. More rarely the network is perfectly regular, with +equidistant circular pores of equal size, and sometimes these are +surrounded by hexagonal frames (fig. 6), as in many #Sphaeroidea#. More +rarely the pores are perfectly irregular, roundish or sometimes polygonal, +of unequal sizes and dissimilar forms (fig. 2). The size of the pores is +very variable between 0.01 and 0.05, usually between 0.015 and 0.025. They +are commonly somewhat broader than the bars between them, more rarely +smaller. The substance of the shell-wall is in the the majority of +Castanellida hyaline, transparent (as in the similar #Sphaeroidea#); in +some larger forms, however, a network of fine axial filaments is visible in +the lattice (fig. 2), and sometimes this seems to be hollow, with an axial +canal (as in the large Orosphaerida). Such an axial filament or fine axial +canal is usually visible in the larger radial spines. The shell-wall of the +Castanellida, however, never exhibits that characteristic structure (with +tangential needles in a cement-like fundamental substance), which we find +in all Circoporida. The latter differ also in the constant presence of +circles of large pores around the bases of the radial spines, which are +never found in the Castanellida. The shell becomes usually stained more or +less purple by carmine, and when burned by fire, becomes of a brown colour. + +The inner surface of the shell is always quite smooth, the outer surface +armed with numerous short and thin radial bristles. Sometimes these +bristles or "by-spines" are very short, but never perfectly wanting. +Usually their length is about one-third or one-fourth of the radius of the +shell, often less, rarely more. They arise from the nodal points between +every three or four neighbouring spines, and are commonly very thin and +straight, pointed, with slightly thickened conical basis. Rarely they are +directed not quite radially, but more or less obliquely. + +The larger radial spines, which arise between the thin bristles or +"by-spines" and may be opposed to the latter as "main-spines," are wanting +in two genera only, in _Castanarium_ and _Castanella_ (Pl. 113, fig. 6). +They are simple in _Castanidium_ (figs. 2, 5, 7) and _Castanissa_ (fig. 1), +irregularly branched in _Castanopsis_ and _Castanura_ (figs. 3, 4). Their +number and disposition is never regular nor symmetrical (as in the majority +of #Sphaeroidea#) and varies even in each single species. In general the +number of main-spines varies between ten and forty (rarely less or more) +usually between twenty and thirty. Their length is commonly about equal to +the diameter of the shell, often somewhat shorter, rarely considerably +longer. Their {1680}thickness is in the majority of species about equal to +the diameter of one or two pores of the lattice. Sometimes they are much +stronger, rarely thinner. + +The form of the radial main-spines is not very variable, usually it is +cylindrical or cylindro-conical, rarely angular, prismatic or pyramidal. +Sometimes they are straight (perfectly radial), at other times more or less +irregularly curved. Usually they are simple, rarely branched; the branches +are always very irregular and exhibit a remarkable tendency to unite by +concrescence (figs. 3, 4). Some thicker forms of spines exhibit a +remarkable structure, the surface being covered with small dimples and +spinules between them (fig. 1); sometimes the dimples are hexagonal (fig. +5_a_). In the axis of the thicker spines there is often visible the same +axial filament or funicle which we find in many other PHAEODARIA, more +rarely a hollow axial canal. + +The mouth of the shell is usually circular, more rarely polygonal or +irregularly roundish (fig. 2). It is either quite smooth (fig. 3, 5, 7) or +armed with a corona of strong teeth (figs. 1, 4, 6). These teeth are +different from the other spines of the shell; they are much thicker than +the radial bristles, and shorter than the main-spines. Their number varies +between three and twenty, usually between five and seven. They are usually +parallel to the main axis, which is determined by the excentric position of +the mouth and the centre of the sphere (figs. 1, 6). The teeth are usually +conical, more or less irregular in size and form, more rarely of equal +size. The corona of teeth is usually sharply separated from the surrounding +lattice-work of the shell, but has no influence on its regular spherical +form. + +The _central capsule_ of the Castanellida immediately determines beyond +doubt their true PHAEODARIAN nature; it lies excentrically in the cavity of +the enclosing shell, and is surrounded at the oral pole by the large and +dark phaeodium. The latter covers the radiate operculum of the capsule +membrane and the tubular proboscis, which arises from it and is directed +towards the shell mouth. Usually the diameter of the spherical central +capsule is about one-third of the shell diameter, rarely one-quarter only, +and in a few cases it attains nearly its half. The calymma, therefore, is +larger than the capsule, and fills up the whole cavity of the shell which +is not occupied by the latter. The greater part of the calymma again is +filled up by the dark green or brown, sometimes black phaeodella, the +roundish granules which compose the voluminous non-transparent phaeodium. +Sometimes the latter proceeds through the mouth and is partially placed +outside the shell (fig. 5). + +The astropyle, or the main-opening of the central capsule, is placed on the +oral pole of its main axis, while its radiate operculum and the tubular +proboscis arising from it possess the same structure as in the other +PHAEODARIA. But the two lateral parapylae or accessory openings which are +present in the majority of the latter seem to be absent in the Castanellida +as well as in the Medusettida and the Challengerida. I could never observe +a trace of them. The proboscis is a small cylindrical tube and is directed +towards the {1681}mouth of the shell, therefore placed in its main axis; it +is usually quite hidden in the dark phaeodium, which occupies the oral half +of the shell-cavity, whilst the capsule lies in the aboral half. The large +nucleus of the central capsule and its double membrane present the same +characters as in the other PHAEODARIA. + +_Synopsis of the Genera of Castanellida._ + + ------------------------------------------------------------------------- + No long radial main-spines (in addition to the constant short bristles + of the shell-surface). + ------------------------------------------------------------------------- + Mouth smooth, 705. _Castanarium_. + + Mouth dentate, 706. _Castanella_. + ------------------------------------------------------------------------- + Long radial main-spines scattered between the short constant bristles + of the shell-surface. + ------------------------------------------------------------------------- + { Mouth smooth, 707. _Castanidium_. + Main spines simple. { + { Mouth dentate, 708. _Castanissa_. + + { Mouth smooth, 709. _Castanopsis_. + Main spines branched. { + { Mouth dentate, 710. _Castanura_. + + + +Genus 705. _Castanarium_,[322] Haeckel, 1879, Sitzungsb. med.-nat. +Gesellsch. Jena, Dec. 12, p. 5. + +_Definition._--#Castanellida# without radial main-spines, with a smooth +mouth. + +The genus _Castanarium_ is the simplest form of all the Castanellida, and +may be regarded as the common ancestral form of this family. The simple +spherical shell has a smooth, toothless mouth and no larger radial spines; +it is densely studded with the simple, radial bristles, which are common to +all Castanellida. The shell therefore is very similar to those species of +the Astrosphaeride _Acanthosphaera_, which represent the subgenus +_Rhapidococcus_ (compare above, p. 210, Pl. 26, fig. 3); it differs from +the latter in the possession of the shell-mouth, which is absent in all +#Sphaeroidea#. + + +1. _Castanarium darwini_, n. sp. + +Pores regular, circular, hexagonally framed, three times as broad as the +bars. Radial bristles half as long as the radius. + +_Dimensions._--Diameter of the shell 0.3 to 0.4, of the pores 0.03. + +_Habitat._--South Atlantic (east of Patagonia), Station 318, depth 2040 +fathoms. + + +{1682}2. _Castanarium hookeri_, n. sp. + +Pores regular, circular, hexagonally framed, twice as broad as the bars. +Radial bristles one-third as long as the radius. + +_Dimensions._--Diameter of the shell 0.55, of the pores 0.025. + +_Habitat._--Indian Ocean, Cocos Islands (Rabbe), surface. + + +3. _Castanarium lyelli_, n. sp. + +Pores regular, circular, without hexagonal frames, of the same breadth as +the bars. Radial bristles twice as long as the diameter of one pore. + +_Dimensions._--Diameter of the shell 0.24, of the pores 0.015. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +4. _Castanarium lubbocki_, n. sp. + +Pores irregularly roundish, about of the same breadth as the roundish, +non-crested bars. Radial bristles one-third as long as the radius. + +_Dimensions._--Diameter of the shell 0.36, of the pores 0.01 to 0.02. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms. + + +5. _Castanarium huxleyi_, n. sp. + +Pores irregularly polygonal, two to three times as broad as the bars, +separated by prominent polygonal crests. Radial bristles half as long as +the radius. + +_Dimensions._--Diameter of the shell 0.45, of the pores 0.02 to 0.05. + +_Habitat._--South Pacific (off Australia), Station 165, surface. + + + +Genus 706. _Castanella_,[323] Haeckel, 1879, Sitzungsb. med.-nat. +Gesellsch. Jena, Dec. 12, p. 5. + +_Definition._--#Castanellida# without radial main-spines, with a dentate +mouth. + +The genus _Castanella_ comprises the most common and most widely +distributed species of Castanellida. It agrees in general shape with its +ancestral form, the preceding _Castanarium_, differing from it only in the +possession of strong teeth, which form a corona around the mouth. + + +{1683}1. _Castanella wyvillei_, n. sp. (Pl. 113, fig. 6). + +Pores regular, circular, of equal size, hexagonally framed, of the same +breadth as the bars. Radial bristles twice as long as the diameter of one +pore. Mouth with five to six parallel, conical strong teeth, which are +twice as long as a bristle (fig. 6_a_). + +_Dimensions._--Diameter of the shell 0.5 to 0.7, of the pores 0.02 to 0.03. + +_Habitat._--North Pacific, Stations 252 to 256, surface. + + +2. _Castanella thomsoni_, n. sp. + +Pores regular, circular, of equal size, hexagonally framed, twice as broad +as the bars. Radial bristles about as long as the diameter of one pore. +Mouth with four strong, conical teeth, forming a regular cross, four times +as long as a bristle. + +_Dimensions._--Diameter of the shell 0.7 to 0.8, of the pores 0.03. + +_Habitat._--South Pacific, Stations 295 to 298, surface. + + +3. _Castanella campbelli_, n. sp. + +Pores regular, circular, hexagonally framed, three times as broad as the +bars. Radial bristles half as long as the radius of the shell. Mouth with a +coronet of eight conical, parallel teeth, of the same length as the +bristles, but four to six times as thick. + +_Dimensions._--Diameter of the shell 0.4 to 0.45, of the pores 0.025. + +_Habitat._--Central Pacific, Stations 270 to 274, surface. + + +4. _Castanella sloggetti_, n. sp. + +Pores subregular, circular, without frames, of different sizes, about twice +as broad as the bars. Radial bristles three times as long as one pore. +Mouth with five or six strong, conical teeth, twice as long as the +bristles. + +_Dimensions._--Diameter of the shell 0.3 to 0.36, of the pores 0.02 to +0.03. + +_Habitat._--Tropical Atlantic, Stations 347 to 349, surface. + + +5. _Castanella balfouri_, n. sp. + +Pores irregular, roundish, two to three times as broad as the bars. +Bristles about one-fourth as long as the radius. Mouth with four strong +conical teeth, forming a cross, somewhat longer and much thicker than the +bristles. + +_Dimensions._--Diameter of the shell 0.22 to 0.28, of the pores 0.01 to +0.02. + +_Habitat._--North Pacific, Stations 240 to 245, surface. + + +{1684}6. _Castanella channeri_, n. sp. + +Pores irregular, roundish, two to four times as broad as the bars. Bristles +nearly half as long as the radius. Mouth with seven to nine short conical +teeth, shorter than the bristles, but much thicker. + +_Dimensions._--Diameter of the shell 0.3 to 0.4, of the pores 0.02 to +0.025. + +_Habitat._--North Atlantic, Stations 352 to 354, surface. + + +7. _Castanella horstoni_, n. sp. + +Pores irregular, polygonal, three to four times as broad as the bars. +Bristles about as long as the radius. Mouth with six stout pyramidal teeth, +which are scarcely one-third as long as the radius. + +_Dimensions._--Diameter of the shell 0.55, of the pores 0.02 to 0.025. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + + +Genus 707. _Castanidium_,[324] Haeckel, 1879, Sitzungsb. med.-nat. +Gesellsch. Jena, Dec. 12, p. 5. + +_Definition._--#Castanellida#, with simple radial main-spines and a simple +smooth mouth. + +The genus _Castanidium_ agrees with its ancestral form _Castanarium_ in the +simple shape of the smooth and toothless mouth, but differs from it in the +possession of long radial main-spines, which are scattered between the +constant radial bristles or by-spines of the surface. The shell agrees +therefore in its general shape with the Astrosphaeride _Heliosphaera_, as +defined above (p. 217, Pl. 26, fig. 9), but differs from it in the +possession of the shell-mouth wanting in all #Sphaeroidea#. + + +1. _Castanidium willemoesi_, n. sp. + +Pores regular, circular, hexagonally framed, twice as broad as the bars. +Bristles three times as long as the diameter of one pore. Radial +main-spines straight, conical, smooth, as long as the radius. + +_Dimensions._--Diameter of the shell 0.3 to 0.4, of the pores 0.012 to +0.016. + +_Habitat._--Central Pacific, Station 263 to 274, surface. + + +2. _Castanidium wildi_, n. sp. + +Pores regular, circular, hexagonally framed, of the same breadth as the +bars. Bristles twice as long as one pore. Radial main-spines straight and +short, cylindrical, with dimpled surface (as in Pl. 113, fig. 1), as broad +as one pore and as long as the diameter of the shell. + +_Dimensions._--Diameter of the shell 0.66, of the pores 0.045. + +_Habitat._--South Pacific, Station 297, surface. + + +{1685}3. _Castanidium buchanani_, n. sp. (Pl. 113, fig. 7). + +Pores regular, circular, without frames, twice as broad as the bars, of +variable size. Bristles five to six times as long as one pore. Radial +main-spines numerous, straight, slender, cylindrical, about as long as the +diameter of the shell. + +_Dimensions._--Diameter of the shell 0.25 to 0.3, of the pores 0.012 to +0.02. + +_Habitat._--Tropical Atlantic, Stations 346 to 349, surface. + + +4. _Castanidium murrayi_, n. sp. (Pl. 113, figs. 5, 5_a_). + +Pores subregular, circular, without frames, three times as broad as the +bars. Bristles three times as long as one pore. Radial main-spines +cylindrical, stout, irregularly curved, longer than the shell-diameter, +covered with longish hexagonal dimples, which are separated by a network of +prominent crests (fig. 5_a_). + +_Dimensions._--Diameter of the shell 0.4 to 0.5, of the pores 0.02 to +0.025. + +_Habitat._--North Atlantic, Station 352 to 354, surface. + + +5. _Castanidium aldrichi_, n. sp. + +Pores subregular, circular, without frames, of variable size, about as +broad as the bars. Bristles four times as long as one pore. Radial +main-spines conico-cylindrical, irregularly curved, straight, about as long +as the radius. (The conical base of the spines is inflated and fenestrated, +therefore the shell is nearly polyhedral.) + +_Dimensions._--Diameter of the shell 0.35 to 0.4, of the pores 0.012 to +0.015. + +_Habitat._--Central Pacific, Stations 270 to 274, surface. + + +6. _Castanidium bromleyi_, n. sp. + +Pores irregular, roundish, two to four times as broad as the bars. Bristles +half as long as the radius. Radial main-spines cylindrical, straight, +slender, longer than the shell-diameter. + +_Dimensions._--Diameter of the shell 0.22 to 0.26, of the pores 0.006 to +0.02. + +_Habitat._--Indian Ocean and Southern Pacific, Stations 162 to 169, +surface. + + +7. _Castanidium bethelli_, n. sp. + +Pores irregular, roundish or polygonal, two to three times as broad as the +bars. Bristles one-third as long as the radius. Radial main-spines +conico-cylindrical, irregularly curved, with dimpled surface, somewhat +longer than the radius. + +_Dimensions._--Diameter of the shell 0.5 to 0.6, of the pores 0.015 to +0.03. + +_Habitat._--North Pacific, Stations 235 to 245, surface. + + +{1686}8. _Castanidium moseleyi_, n. sp. (Pl. 113, fig. 2). + +Pores irregular, roundish or polygonal, two to four times as broad as the +bars. Bristles about as long as the diameter of one pore, or a little +longer. Radial main-spines cylindrical, irregularly curved, somewhat longer +than the diameter of the shell; their base is more or less inflated and +fenestrated, therefore the shell is nearly polyhedral. + +_Dimensions._--Diameter of the shell 0.7 to 0.8, of the pores 0.01 to 0.04. + +_Habitat._--Tropical Atlantic, Stations 346 to 349, surface. + + + +Genus 708. _Castanissa_,[325] Haeckel, 1879, Sitzungsb. med.-nat. +Gesellsch. Jena, Dec. 12, p. 5. + +_Definition._--#Castanellida# with simple radial main-spines and a dentate +mouth. + +The genus _Castanissa_ agrees with the preceding _Castanidium_ in the +possession of large radial main-spines, scattered between the numerous +bristles or by-spines of the surface; but it differs from it in the +possession of teeth around the mouth, identical with those of _Castanella_; +it may be derived therefore either from the latter by development of +main-spines, or from the former by formation of teeth. + + +1. _Castanissa challengeri_, n. sp. (Pl. 113, fig. 1). + +Pores regular, circular, three times as broad as the bars. Bristles +one-fourth as long as the radius. Radial main-spines (about twelve) very +stout, straight, cylindrical, at the distal end conical, pointed, with +dimpled surface, about half as long as the radius. Mouth very large, +circular, about one-third as broad as the shell, with a corona of twelve to +sixteen very large, triangular, parallel teeth. + +_Dimensions._--Diameter of the shell 0.7 to 0.8, of the pores 0.03. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + +2. _Castanissa pearceyi_, n. sp. + +Pores regular, circular, twice as broad as the bars. Bristles half as long +as the radius. Radial main-spines (about twenty) slender, cylindrical, +smooth, irregularly curved, about as long as the radius. Mouth large, half +as broad as the radius, with a corona of ten to twelve irregular, slender +teeth. + +_Dimensions._--Diameter of the shell 0.5 to 0.6, of the pores 0.02. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +{1687}3. _Castanissa richardsi_, n. sp. + +Pores subregular, circular, about as broad as the bars. Bristles twice as +long as one pore. Radial main-spines (about twenty) slender, cylindrical, +irregularly curved, with dimpled surface (like those in Pl. 113, fig. +5_a_). Mouth with a corona of six stout, parallel, triangular teeth. + +_Dimensions._--Diameter of the shell 0.3 to 0.35, of the pores 0.015. + +_Habitat._--North Atlantic, Station 354, surface. + + +4. _Castanissa crosbiei_, n. sp. + +Pores irregular, roundish, two to three times as broad as the bars. +Bristles one-third as long as the radius. Radial main-spines very numerous, +straight, cylindrical, smooth, about as long as the diameter of the shell. +Mouth with ten or twelve irregular, conical, parallel teeth. + +_Dimensions._--Diameter of the shell 0.28, of the pores 0.01 to 0.015. + +_Habitat._--North Pacific, Stations 231 to 235, surface. + + +5. _Castanissa macleani_, n. sp. + +Pores irregular, roundish or polygonal, two to four times as broad as the +bars. Bristles about one-fourth as long as the radius. Radial main-spines +numerous, straight, conical, stout, with dimpled surface, shorter than the +radius. Mouth with six to eight irregular conical teeth. + +_Dimensions._--Diameter of the shell 0.32, of the pores 0.012 to 0.024. + +_Habitat._--Tropical Pacific, Station 268, depth 2900 fathoms. + + +6. _Castanissa hoylei_, n. sp. + +Pores irregular, polygonal, two to three times as broad as the bars. +Bristles nearly half as long as the radius. Radial main-spines (about +thirty) very long and thin, cylindrical, irregularly curved, at the conical +base inflated and fenestrated; shell therefore slightly polyhedral. Mouth +with five strong conical teeth. + +_Dimensions._--Diameter of the shell 0.35 to 0.4, of the pores 0.02 to +0.03. + +_Habitat._--North Pacific, Station 245 to 250, surface. + + + +Genus 709. _Castanopsis_,[326] Haeckel, 1879, Sitzungsb. med.-nat. +Gesellsch. Jena, Dec. 12, p. 5. + +_Definition._--#Castanellida# with branched radial main-spines and a simple +smooth mouth. + +The genus _Castanopsis_ differs from its ancestral form _Castanidium_ in +the ramification of the radial main-spines; the branches are usually very +irregular and often partly {1688}confluent. The shell is very similar to +the Astrosphaeride _Cladococcus_ (compare above p. 223, Pl. 27), but +differs from it in the possession of the shell-mouth, absent in all +#Sphaeroidea#. + + +1. _Castanopsis naresi_, n. sp. (Pl. 113, fig. 3). + +Pores subregular, circular, about twice as broad as the bars. Bristles +twice as long as one pore. Radial main-spines somewhat shorter than the +diameter of the shell, straight, cylindrical, in the proximal half simple, +in the distal half irregularly branched, each with ten to twelve partly +confluent branches. + +_Dimensions._--Diameter of the shell 0.6 to 0.7, of the pores 0.02 to 0.03. + +_Habitat._--Tropical Atlantic, Station 347 to 349, surface. + + +2. _Castanopsis macleari_, n. sp. + +Pores irregular, roundish, two to four times as broad as bars. Bristles +half as long as the radius. Radial main-spines about as long as the radius, +stout and straight, cylindrical, forked at the distal end, with two or +three unequal fork-branches. + +_Dimensions._--Diameter of the shell 0.42, of the pores 0.015 to 0.03. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +3. _Castanopsis fergusoni_, n. sp. + +Pores irregular, roundish or polygonal, about as broad as the bars. +Bristles three times as long as one pore. Radial main-spines somewhat +longer than the diameter of the shell, cylindrical, with irregular and +partly confluent lateral branches (similar to Pl. 113, fig. 4_a_). + +_Dimensions._--Diameter of the shell 0.55, of the pores 0.012 to 0.016. + +_Habitat._--North Atlantic, Station 354, surface. + + + +Genus 710. _Castanura_,[327] Haeckel, 1879, Sitzungsb. med.-nat. Gesellsch. +Jena, Dec. 12, p. 5. + +_Definition._--#Castanellida# with branched radial main-spines and a +dentate mouth. + +The genus _Castanura_ differs from the preceding _Castanopsis_ in the +possession of a corona of teeth surrounding the mouth, similar to that of +_Castanissa_. It differs from the latter in the ramification of the radial +main-spines, wherein it agrees with the former. _Castanura_ may therefore +be derived either from _Castanissa_ by ramification of the main-spines, or +from _Castanopsis_ by development of teeth around the mouth. + + +{1689}1. _Castanura tizardi_, n. sp. (Pl. 113, fig. 4, 4_a_). + +Pores regular, circular, without hexagonal frames, twice as broad as the +bars. Bristles twice as long as one pore. Radial main-spines somewhat +longer than the radius, straight, very stout, with irregular lateral +branches, which are partly confluent. Mouth with six strong conical teeth. + +_Dimensions._--Diameter of the shell 0.6, of the pores 0.03. + +_Habitat._--Tropical Atlantic, Station 346, surface. + + +2. _Castanura havergali_, n. sp. + +Pores regular, circular, hexagonally framed, as broad as the bars. Bristles +three times as long as one pore. Radial main-spines as long as the +shell-diameter, in the basal half simple, in the distal half with +irregular, not confluent, lateral branches. Mouth with ten to twelve +irregular, parallel, conical teeth of different sizes. + +_Dimensions._--Diameter of the shell 0.5, of the pores 0.045. + +_Habitat._--Indian Ocean, Madagascar (Rabbe), surface. + + +3. _Castanura swirei_, n. sp. + +Pores regular, circular, hexagonally framed, as broad as the bars. Bristles +half as long as the radius. Radial main-spines straight, longer than the +shell-diameter; on the distal end with a few irregular, confluent, lateral +branches. Mouth with six larger and six alternate smaller, parallel, +conical teeth. + +_Dimensions._--Diameter of the shell 0.28, of the pores 0.015. + +_Habitat._--North Pacific, Station 253, surface. + + +4. _Castanura carpenteri_, n. sp. + +Pores irregular, roundish, twice to four times as broad as the bars. +Bristles about as long as the largest pores. Radial main-spines irregularly +curved, longer than the shell-diameter, with inflated and fenestrated +conical base; in the distal half irregularly branched, with simple, not +confluent, lateral branches. Mouth with six to nine irregular, strong, +conical teeth. + +_Dimensions._--Diameter of the shell 0.3, of the pores 0.012 to 0.025. + +_Habitat._--South Atlantic, Station 331, depth 1715 fathoms. + + + +Family LXXXI. #CIRCOPORIDA#, Haeckel, 1879 (Pls. 114-117). + + _Circoporida_, Haeckel, 1879, Sitzungsb. med.-nat. Gesellsch. Jena, Dec. + 12, p. 5. + +_Definition._--PHAEODARIA with a spherical or polyhedral shell, exhibiting +a peculiar solid porcellanous structure, with a stellate circle of radial +pores around the base of the hollow radial spines. Mouth usually with +teeth. Surface of the shell {1690}tabulate, panelled or dimpled. Central +capsule excentric, placed in the aboral half of the shell-cavity. + +The family #Circoporida# comprises those PHAEODARIA in which the simple +spherical or polyhedral shell exhibits a peculiar porcellanous structure, +possesses a simple mouth, and is particularly distinguished by the constant +character denoted by their name, viz., by circles of pores surrounding the +base of the radial spines. It agrees in these striking peculiarities with +the following family, the Tuscarorida, but differs from them essentially by +the spherical or polyhedral form of the shell, which is never ovate, with +the main axis prolonged. The radial spines, variable in number, are +regularly or symmetrically disposed in all Circoporida, whilst they are +arranged around the poles of the main axis in all Tuscarorida. Whilst the +latter are always extremely large, more than a millimeter in size, the +former are much smaller and never reach the diameter of a millimeter. The +number of genera and species in this family is not large, and the majority +are very rare, but they belong to the most remarkable Radiolaria by the +peculiar structure, as well as by the geometrical regularity of the +polyhedral shell. + +The Circoporida may be divided into two different subfamilies, the +Circogonida and the Haeckelinida. The latter are represented by the single +genus _Haeckeliana_ (Pl. 114), and possess a spherical shell with numerous +small dimples between the circles of pores, and numerous simple radial +spines which do not exhibit a regular arrangement. The Circogonida, on the +other hand, comprise all other genera (Pls. 115-117) and possess a panelled +shell with polygonal plates, and a certain number of radial spines, which +are regularly disposed on the corners of the polyhedral shell, and usually +armed with verticillate bristles and terminal forks or spathillae. Perhaps +the Circogonida and Haeckelinida may be better considered as two separate +families. + +The geometrical fundamental form of the shell is in the Circoporida of the +highest interest, since it exhibits regular proportions, which are very +rare in other organic forms, generally some rare forms of regular +polyhedrons. The shell in all members of this family belongs to that group +of geometrical forms which I have called in my General Morphology +"_Polyaxonia_" (vol. i., 1866, pp. 406-416). The shell therefore is +constantly an "endospherical polyhedron," _i.e._, a polyhedron, all the +corners of which lie in a spherical surface. The corners are always +indicated by the bases of the radial spines arising from the surface of the +shell and marking its axes, and it is immaterial whether the shell itself +is a true polyhedron or a sphere; for in the latter case also the radial +spines mark the axes of the polyhedron. + +The six genera which we here distinguish among the Circoporida, represent +six different fundamental forms. _Circoporus_ (Pl. 115, figs. 1-3; Pl. 117, +figs. 5, 6) possesses six radial spines, opposite in pairs in three +diameters, perpendicular one to another; it agrees therefore with the +Cubosphaerida (p. 169, Pls. 21-25) and {1691}represents the regular +octahedron, with eight congruent triangular faces and six corners. It has +the same form as the well-known antheridia of Chara (Gener. Morphol., vol. +i. p. 412). _Circogonia_ (Pl. 115, figs. 8-10; Pl. 117, fig. 1) exhibits +twelve radial spines, opposite in pairs in six equidistant diameters. The +surface of the shell is divided into twenty equal and equilateral +triangles, and agrees therefore with the regular icosahedron. The same form +appears also in some forms of _Aulosphaera_, and in several Astrosphaerida +(Gener. Morphol., vol. i. p. 411). _Circorrhegma_ (Pl. 117, fig. 2) +possesses a regular shell with twelve equal pentagonal faces and twenty +equidistant corners, from which arise twenty regularly disposed radial +spines. It represents therefore the regular "pentagonal dodecahedron," the +same remarkable form which is found in some Astrosphaerida, and in the +pollen-grains of some plants, _e.g._, _Bucholzia maritima_, _Fumaria +spicata_, _Polygonum amphibium_, &c. (Gener. Morphol., vol. i. p. 412, Taf. +ii. fig. 18). + +The three genera of Circoporida mentioned therefore represent three +different forms of regular polyhedrons, in the exact mathematical sense, +viz., _Circoporus_, the regular octahedron, _Circogonia_, the regular +icosahedron, and _Circorrhegma_, the regular dodecahedron. In each of these +three regular forms all the faces, edges, and corners are equal. The +remaining three genera of Circoporida represent, however, three forms of +subregular or irregular endospherical polyhedra, which are not perfectly +regular. _Circospathis_ (Pl. 115, figs. 4-7; Pl. 117, fig. 3) is a rather +common form, and constantly possesses nine symmetrically disposed radial +spines; the shell is either spherical or polyhedral, with fourteen +triangular faces and thirty edges; the nine spines lie in three meridional +planes, which are crossed at equal angles (three equidistant spines in each +plane). We call this remarkable form the tetradecahedron; it appears also +in some Astrosphaerida (_e.g._, in _Haliomma echinaster_, figured in my +Monograph, Taf. xxiv. fig. 1). _Circostephanus_ (Pl. 116, fig. 3) exhibits +a subregular polyhedral shell with a variable number of triangular faces +and of radial spines (twenty-four to forty or more). _Circostephanus +sexagenarius_ possesses sixty triangular equilateral faces, which are +disposed in twelve pentagonal groups (each with five faces), so that the +shell seems to be derived from a regular pentagonal dodecahedron, the +twelve regular faces of which are divided each into five congruent +triangles. From its corners arise thirty-two radial spines (twelve from the +central points of the pentagons, twenty from the meeting corners of every +three pentagons). In other cases the number of faces and radial spines +seems to be larger and their arrangement more irregular. The same may be +said of _Haeckeliana_, in which the dimpled shell is constantly spherical, +and possesses a variable number of radial spines, from sixteen to +fifty-five (usually between thirty and forty). + +The structure of the shell in the Circoporida is the same as in the +Tuscarorida, of a peculiar porcellanous nature. The shell-wall is very +thick, more or less opaque, and in direct light whitish or yellowish. Its +surface is dimpled, with numerous small, circular, {1692}roundish or +polygonal dimples in _Haeckeliana_ (Pl. 114, figs. 1-6). In the +Circogonida, however, the surface is panelled, with regular or irregular +polygonal plates, often separated by high prominent crests (Pl. 115, figs. +4-9, &c.). Numerous simple thin needles of silica lie tangentially disposed +and irregularly scattered in the porcellanous or cement-like substance of +the thick shell-wall. Under a strong lens this substance appears finely +punctate, being probably pierced by numerous very fine pores. The surface +of the shell is therefore minutely roughened, and often appears quite black +under the microscope, by the adhesion of innumerable fine air-bubbles. In +all Circoporida, as well is in the Tuscarorida, the porcellanous shell has +not the perfect transparency of the purely siliceous shells of other +Radiolaria; its refractive power is somewhat different from the latter; it +becomes deeply stained by carmine and browned by fire, and seems therefore +to consist of a peculiar carbonic silicate. + +The shell in all Circoporida exhibits a simple, excentric mouth, which +corresponds to the main osculum of the central capsule. The excentric +position of this shell-mouth has no influence on the regular form of the +shell. The mouth is either circular or polygonal, usually about as large as +a basal circle of pores. It is always armed with prominent conical or +pyramidal teeth, the number of which is variable and seems to depend partly +upon the number of the shell-faces or the radial spines. _Circoporus_ has +usually four cruciate teeth (Pl. 115, fig. 1; Pl. 117, figs. 4, 5). +_Circorrhegma_ exhibits a pentagonal mouth with five teeth (Pl. 117, fig. +2). _Circogonia_ possesses a hexagonal mouth with six teeth (Pl. 115, fig. +8; Pl. 117, fig. 1). _Circospathis_ has no constant number; some species +have five teeth (Pl. 115, fig. 4), others four (Pl. 115, fig. 10), others +nine (Pl. 117, fig. 3_a_). _Circostephanus_ is also variable; one species +exhibits eight teeth (Pl. 116, fig. 3_a_), another ten, another twelve. In +_Haeckeliana_ (Pl. 114, fig. 3) the teeth are smaller and more numerous. +Usually the teeth arise vertically from the surface of the shell and are +spinulate; more rarely their points are directed towards the centre of the +mouth. Sometimes numerous thin needles arise between the teeth (Pl. 115, +fig. 10). + +The radial spines of the Circoporida are tubular, usually cylindrical and +conical at the thickened base, more rarely prismatic or slenderly +pyramidal, with three or more edges; sometimes the edges are spirally wound +around the axis (Pl. 115, fig. 6). In the majority of species their length +is about equal to the diameter of the shell; often they are somewhat +shorter, more rarely longer. Their tubular structure is always the same as +in the Tuscarorida; the wall of the tube is thick, and in the axis of its +cavity lies an axial cord or funicle, which is connected with the wall by +numerous horizontal, simple, or branched threads (Pl. 115, figs. 6, 7). The +axial funicle itself is either a simple thread of silica, or a strand, +composed of three to fifteen or more filaments, which are closely twisted +like a rope around the axis of the spine, and arise separately from the +bridges between the pores of the basal circle (Pl. 115, figs. 7, 9). The +number of {1693}pores in these circles is very variable, commonly from +three to nine, sometimes twelve to fifteen or more; their form is usually +irregularly ovate (Pl. 115, figs. 7, 9). The bridges between the pores +usually bear numerous siliceous threads or bristles, which are curved +downwards or upwards (Pl. 115, figs. 4-6). Sometimes the spines are +entirely covered with similar bristles or cilia (Pl. 117, figs. 2-5), more +rarely with regular verticils of lateral branches (Pl. 117, fig. 6). + +The distal ends of the radial spines are simple in _Haeckeliana_ (Pl. 114), +whilst in the other Circoporida they are usually (or perhaps constantly) +either forked or armed with a verticil of terminal branches. When the +spines are simply forked, their two terminal branches lie in certain +meridional planes (Pl. 117, fig. 5). The same is probably the case when +they bear three divergent branches (Pl. 115, figs. 1, 2), or four crossed +branches (Pl. 117, figs. 4, 6). The larger species usually bear a corona of +five curved branches disposed around the distal apex of each spine (Pl. +116, fig. 3; Pl. 117, figs. 1, 2). Sometimes the formation of these coronas +is twice or more often repeated, so that the spines appear verticillate. + +The _central capsule_ of the Circoporida (Pl. 115, fig. 8; Pl. 117, fig. 6) +is usually about half as large as the enclosing shell, and lies +excentrically in that half of its cavity which is remote from the +shell-mouth (Pl. 115, fig. 8). The other half (near the mouth) is filled up +by the cap-shaped, dark phaeodium. The proboscis, or the central tubule of +the astropyle, is hidden in the axis of the blackish phaeodium, and is +directed towards the mouth of the shell; it is often S-shaped, more or less +curved. The circular radiate operculum of the astropyle, placed on the base +of the proboscis, exhibits numerous branched radial ribs, and closes the +main-opening like the lid of a tea-kettle (Pl. 115, fig. 3). The number of +the parapylae, or the accessory openings of the capsule, which in the +majority of PHAEODARIA is two, seems to be usually increased in the +Circoporida. In _Circoporus_ the capsule seems to posses six and in +_Circospathis_ nine secondary openings, and therefore there is some +probability that each circle of pores on the base of a radial spine +corresponds to a secondary opening of the capsule. In _Haeckeliana_, +however (Pl. 114), I could observe no parapylae at all. These accessory +openings are always very small in the Circoporida, and may be easily +overlooked. Furthermore, the number of observations respecting this +difficult point is too small, and their certainty not satisfactory; it +requires therefore further accurate examination, as also does the whole +central capsule of the Circoporida. + +The numerous and remarkable characters of shape and structure, which we +have described above as occurring in the Circoporida, are also found in the +following closely allied family, the Tuscarorida; all the species are +inhabitants of great depths. Perhaps it may therefore be more convenient to +separate these two families from the other PHAEOGROMIA as a peculiar order, +under the name PHAEOCALPIA. + +{1694}_Synopsis of the Genera of Circoporida._ + + ------------------------------------------------------------------------- + I. Subfamily Circogonida. + Shell spherical or polyhedral with panelled structure and polygonal + plates. A certain number of radial spines are geometrically disposed. + ------------------------------------------------------------------------- + Shell octahedral (or + spherical), Six radial spines, 711. _Circoporus_. + + Shell tetradecahedral, Nine radial spines, 712. _Circospathis_. + + Shell icosahedral, Twelve radial spines, 713. _Circogonia_. + + Shell dodecahedral, Twenty radial spines, 714. _Circorrhegma_. + + Shell polyhedral, Twenty-four to forty + or more radial spines, 715. _Circostephanus_. + ------------------------------------------------------------------------- + II. Subfamily Haeckelinida. + ------------------------------------------------------------------------- + Shell spherical, with dimpled structure, and a + variable number of radial spines (without + polygonal plates), 716. _Haeckeliana_. + + + +Subfamily 1. CIRCOGONIDA, Haeckel. + +_Definition._--#Circoporida# with panelled shell, composed of polygonal +plates. The shell is usually polyhedral, more rarely spherical, and the +radial spines are usually (or perhaps constantly) branched and regularly +arranged. + + + +Genus 711. _Circoporus_,[328] Haeckel, 1879, Sitzungsb. med.-nat. +Gesellsch. Jena, Dec. 12, p. 5. + +_Definition._--#Circoporida# with a spherical or regularly octahedral +shell, composed of eight congruent, triangular plates, with six corners +from which arise six radial spines, opposite in pairs in three diameters, +perpendicular one to another. + +The genus _Circoporus_, the simplest among the Circoporida, is +distinguished by the regular octahedral form of the shell, with the three +equal axes of the regular crystalline system perpendicular one to another. +Six equal radial spines, arising from the six corners, lie opposite in +pairs in those three dimensive axes. The eight equal triangular faces of +the octahedron are sometimes plane, sometimes concave or convex, and +sometimes the shell becomes spherical. In this case it becomes very similar +to the Hexastylida among the #Sphaeroidea#. + + +1. _Circoporus sexfurcus_, Haeckel (Pl. 117, fig. 5). + + _Challengeria_ sp., John Murray, 1876, Proc. Roy. Soc. Lond., vol. xxiv. + pl. xxiv. fig. 5. + +Shell spherical, covered with irregular, polygonal plates. Six radial +spines shorter than the diameter of the shell, covered with thin curved +bristles, in the proximal half cylindrical, in the distal half forked, each +with two equal curved fork-branches. Around the ciliated base of each spine +a {1695}corona of twelve to sixteen pores surrounded by a circle of +numerous, curved, longer bristles. Mouth cruciform, with four triangular, +convergent teeth. + +_Dimensions._--Diameter of the shell 0.55, length of the spines 0.4. + +_Habitat._--South Pacific, Station 289, depth 2550 fathoms. + + +2. _Circoporus hexastylus_, n. sp. (Pl. 117, fig. 4). + +Shell regularly octahedral, with eight plane, congruent, triangular faces, +which are covered with a very delicate network of small, regular, hexagonal +plates. Six radial spines as long as the radius of the shell, four-sided +pyramidal, simple, in the basal half covered with numerous curved bristles. +Around the base of each spine a corona of four equal pores, surrounded by a +circle of twelve short teeth. Apex with four crossed, curved branches (like +those of _Circospathis tetrodon_). Mouth cruciform, with four smooth teeth. + +_Dimensions._--Diameter of the shell 0.24, length of the spines 0.12. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +3. _Circoporus characeus_, n. sp. + +Shell spherical, covered with a delicate network of irregular polygonal +plates. Six radial spines longer than the diameter of the shell, +cylindrical, covered with numerous curved bristles, each with eight pores +at the base surrounded by a circle of long bristles. Apex of each spine +with a trident or fuscina, similar to that of the following species. +Similar to an antheridium of Chara. + +_Dimensions._--Diameter of the shell 0.32, length of the spines 0.4. + +_Habitat._--South Pacific, Station 285, depth 2375 fathoms. + + +4. _Circoporus sexfuscinus_, n. sp. (Pl. 115, figs. 1-3). + +Shell subregular, octahedral, with eight triangular, concave, somewhat +unequal faces, which are covered with an extremely delicate network of +small square dimples, and furrowed by radial crests arising from the bases +of the spines (fig. 2). Six radial spines about as long as the diameter of +the shell, four-sided, prismatic, with rounded edges; each in the basal +half with a verticil of four crossed, curved bristles (fig. 1), sometimes +with two verticils (fig. 2); on the distal apex inflated, armed with a +trident or fuscina. Around the base of each spine four crossed elliptical +pores. Mouth cruciform, with four small teeth (fig. 1). + +_Dimensions._--Diameter of the shell 0.2 to 0.25, length of the spines 0.2 +to 0.25. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms. + + +5. _Circoporus octahedrus_, n. sp. (Pl. 117, fig. 6). + +Shell regularly octahedral, with eight plane, or slightly convex, +congruent, triangular faces, which are covered with very small, regular, +triangular plates (like those of _Polypetta tabulata_, Pl. 116, fig. 2). +Six stout radial spines, about as long as the diameter of the shell, +four-sided prismatic, {1696}covered with three or four verticils of four +long curved bristles; at the distal apex inflated, with four crossed, +divergent, stout, curved horns. Around the pyramidal base of each spine a +corona of eight pores (two on each of the four faces). Mouth cruciform, +with four triangular, convergent teeth. + +_Dimensions._--Diameter of the shell 0.16, length of the spines 0.18. + +_Habitat._--South Pacific, Station 298, depth 2225 fathoms. + + + +Genus 712. _Circospathis_,[329] Haeckel, 1879, Sitzungsb. med.-nat. +Gesellsch. Jena, Dec. 12, p. 5. + +_Definition._--#Circoporida# with a subregular, spherical, or polyhedral +shell, composed of fourteen triangular, nearly equal plates, with nine +corners, from, which arise nine radial spines, symmetrically disposed. + +The genus _Circospathis_ exhibits the remarkable and peculiar form of a +"Tetradecahedron," or a subregular polyhedron with fourteen triangular +faces, thirty edges, and nine corners, from which arise nine radial spines. +These lie in three meridional planes, which are crossed at equal angles +(three equidistant spines in each plane). The same interesting form occurs +also in some Astrosphaerida, which bear nine regularly disposed radial +spines, as _Haliomma echinaster_. All four observed species of +_Circospathis_ are South Atlantic. + + +1. _Circospathis furcata_, n. sp. (Pl. 115, figs. 4-6). + +Shell polyhedral or nearly spherical, with nine prominent corners, from +which arise nine radial spines, about as long as the diameter of the shell. +The polygonal plates of the shell are separated by high crests, usually +hexagonal or pentagonal, irregular, about twelve to fifteen on the half +meridian. Radial spines cylindrical, straight, about as long as the +diameter of the shell, with spirally turned edges, covered with numerous +curved bristles, at the distal end forked; the two fork branches curved, +one-third as long as the simple basal part. The inflated base of each spine +is surrounded by a corona of nine to twelve ovate basal pores. Mouth +pentagonal, with five thick, mammillate and spinulate, somewhat convergent +teeth (fig. 5). + +_Dimensions._--Diameter of the shell 0.6, length of the spines 0.5. + +_Habitat._--South Atlantic (east of Buenos Ayres), Station 325, depth 2650 +fathoms. + + +2. _Circospathis novena_, n. sp. (Pl. 117, figs. 3, 3_a_). + +Shell polyhedral (tetradecahedral), with fourteen triangular, plane, or +slightly convex faces, covered with small, irregular, polygonal (usually +hexagonal) plates, and nine prominent corners, from which arise nine radial +spines, shorter than the diameter of the shell. Each spine is surrounded at +the broader base by a circle of twelve to sixteen pores and a corona of +bristles, and bears at the {1697}inflated distal apex a trident or fuscina, +similar to that of _Circoporus sexfuscinus_ (Pl. 115, fig. 2). Mouth with +nine convergent, conical, denticulate teeth (fig. 3_a_). + +_Dimensions._--Diameter of the shell 0.6, length of the spines 0.4. + +_Habitat._--South Atlantic, Station 318 (east of Patagonia), depth 2040 +fathoms. + + +3. _Circospathis tetradeca_, n. sp. + +Shell spherical, covered with irregular, polygonal plates. Nine radial +spines, cylindrical, as long as the radius of the shell, bristly, armed at +the distal apex with a trident. (In one specimen six spines possessed three +terminal branches, two spines two branches, and one spine four branches.) +The broader base of each spine is surrounded by a corona of nine pores and +a circle of curved bristles. Mouth with nine smooth conical teeth. + +_Dimensions._--Diameter of the shell 0.55, length of the spines 0.3. + +_Habitat._--South Atlantic, Station 332 (west of Tristan da Cunha), depth +2200 fathoms. + + +4. _Circospathis tetrodonta_, n. sp. (Pl. 115, fig. 10). + +Shell subspherical or polyhedral, with fourteen triangular, convex faces, +covered with irregular polygonal plates. Nine radial spines cylindrical, +nearly smooth, about as long as the diameter of the shell; at the distal +apex with four strong curved horns, like those of _Circoporus hexastylus_, +Pl. 117, fig. 4. Each spine is surrounded at the base by a corona of nine +irregular pores. Mouth with four large, prominent, conical teeth, which are +spinulate, with vertical inner edge (fig. 10). + +_Dimensions._--Diameter of the shell 0.5, length of the spines 0.45. + +_Habitat._--South Atlantic, Station 323 (east of Buenos Ayres), depth 1900 +fathoms. + + + +Genus 713. _Circogonia_,[330] n. gen. + +_Definition._--#Circoporida# with a regular icosahedral shell, composed of +twenty congruent, triangular plates, with twelve corners, from which arise +twelve radial spines. + +The genus _Circogonia_ is remarkable for the regular icosahedral form of +its shell, a geometrical fundamental form, which occurs very rarely in +organised bodies (as in _Aulacantha icosahedra_, and in some Astrosphaerida +with twelve regularly disposed radial spines). The shell is composed of +twenty triangular, equilateral and congruent plates, which are sometimes +separated by prominent crests; their surface is panelled by smaller +hexagonal or polygonal secondary plates. The thirty edges between the +plates are sometimes thickened. From the twelve corners of the regular +icosahedron (where every five triangular plates meet), twelve equal radial +spines arise, each of which is surrounded at the base by a corona of nine +to sixteen pores. Two species only of _Circogonia_ have been observed; the +one has smooth spines, forked at the distal end, {1698}the other bears +numerous curved bristles around each spine, and at the distal end a +verticil of five curved branches. The mouth of the shell (placed in the +centre of one of the triangular plates) is in both species armed with six +teeth. Both species are found in the Tropical Atlantic. + + +1. _Circogonia icosahedra_, n. sp. (Pl. 117, figs. 1, 1_a_). + +Shell regularly icosahedral, with twenty equal, triangular, nearly plane +faces, which are separated by thirty prominent, crest-like edges, and +covered by a delicate network of small, subregular, hexagonal plates. +Twelve radial spines nearly conical, one and a half times as long as the +radius of the shell, with five prominent edges. The campanulate base of +each spine is covered with numerous long, curved bristles, surrounded by a +circle of twelve to sixteen ovate, irregular pores, and separated from the +slender distal part by a constriction. The distal apex of the spine is +surrounded by a verticil of five conical, curved branches (corresponding to +the five edges of the spines, and to the five faces, which meet in the +corners where the spine arises). Mouth hexagonal, with six conical, +spinulate teeth, convergent towards its centre (fig. 1_a_). + +_Dimensions._--Diameter of the shell 0.75, length of the spines 0.5. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + +2. _Circogonia dodecacantha_, n. sp. (Pl. 115, figs. 8, 9). + +Shell subregularly icosahedral, with twenty equal, triangular, slightly +convex faces, which are not separated by prominent crests, but covered with +a network of irregular polygonal plates. Twelve radial spines, cylindrical, +smooth, about as long as the diameter of the shell, forked at the distal +end with two divergent, slightly curved branches (similar to _Circospathis +furcata_, Pl. 115, figs. 4-6). The conical base of each spine is surrounded +by a circle of nine to twelve irregular, ovate pores (fig. 9). Mouth +circular, with a corona of six conical, smooth teeth which arise +perpendicularly from the shell (in the upper part of fig. 8, at left). + +_Dimensions._--Diameter of the shell 0.6, length of the spines 0.7. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms. + + + +Genus 714. _Circorrhegma_,[331] n. gen. + +_Definition._--#Circoporida# with a regular dodecahedral shell, composed of +twelve congruent, pentagonal plates, with twenty corners, from which arise +twenty radial spines. + +The genus _Circorrhegma_ is remarkable for the geometrical regularity of +its shell, which represents a pentagonal dodecahedron. The shell is +therefore composed of twelve equal and regular pentagonal plates, and these +are separated in the only known {1699}species by thirty prominent +crest-like edges. From the corners of the dodecahedron, at which every +three pentagons meet, arise twenty radial spines, opposite in pairs in ten +equidistant axes. + + +1. _Circorrhegma dodecahedra_, n. sp. (Pl. 117, figs. 2, 2_a_). + +Shell dodecahedral, with twelve equal and regular, plane, pentagonal +plates, which are separated by thirty prominent crests, and bear a network +of numerous polygonal (usually also pentagonal), smaller plates. Twenty +radial spines about as long as the radius of the shell, three-sided +prismatic, covered with numerous bristles; each surrounded at the thickened +base by a circle of twelve to sixteen pores, and at the distal apex by a +corona of five curved, terminal branches. Mouth pentagonal, with five +conical, subvertical, spinulate teeth (fig. 2_a_). + +_Dimensions._--Diameter of the shell 0.8, length of the spines 0.5. + +_Habitat._--Indian Ocean, Madagascar (Rabbe). + + + +Genus 715. _Circostephanus_,[332] Haeckel, 1879, Sitzungsb. med.-nat. +Gesellsch. Jena, Dec. 12, p. 5. + +_Definition._--#Circoporida# with a subregular, polyhedral or nearly +spherical shell, composed of thirty to sixty or more triangular plates, +with twenty-four to thirty-two or more corners, from which arise radial +spines, symmetrically disposed. + +The genus _Circostephanus_ comprises those Circoporida in which the +porcellanous shell is an endospherical polyhedron, with numerous (thirty to +sixty or more) triangular faces, and has a variable number of radial spines +(twenty-four to forty or more), arising from its corners. The number of +faces and corners seems to be variable in this genus, but may perhaps be +typical in some species. _Circostephanus sexagenarius_ has the typical form +of a "Sexagenal-Polyhedron," with sixty equal triangular faces and +thirty-two corners, and may be derived from the "Pentagonal-Dodecahedron" +(_Circorrhegma_) by dividing its twelve pentagonal faces each into five +congruent triangles. + + +1. _Circostephanus coronarius_, n. sp. (Pl. 116, figs. 3, 3_a_, 3_b_). + +Shell polyhedral, with thirty-two to forty triangular, concave faces of +nearly equal size, which are separated by high prominent crests. From the +elevated corners of the polyhedron arise twenty-four to thirty radial +spines, which are three-sided prismatic or nearly cylindrical, about as +long as the radius of the shell, and covered with long curved bristles. The +distal end of each spine is surrounded by a verticil of five stout, curved +branches, its pyramidal base by a corona of five (or {1700}sometimes six) +ovate, basal pores (fig. 3_b_). Mouth armed with a corona of eight short, +conical, vertical, spinulate teeth (fig. 3_a_). + +_Dimensions._--Diameter of the shell 0.4 to 0.5, length of the spines 0.2 +to 0.25. + +_Habitat._--South-Eastern Pacific (off Valparaiso), Station 298, depth 2225 +fathoms. + + +2. _Circostephanus sexagenarius_, n. sp. + +Shell polyhedral, with sixty triangular, equilateral congruent faces which +are nearly plane, and separated by high prominent crests. They are disposed +in twelve pentagonal groups, each with five faces, so that they appear as +if derived from a regular pentagonal dodecahedron, the twelve regular faces +of which are each divided into five congruent triangles, meeting in its +centre. From the elevated corners of the polyhedron arise thirty-two radial +spines (twelve in the central points of the pentagons, twenty in the +meeting corners of every three pentagons). The radial spines are nearly as +long as the diameter of the shell, cylindrical, spinulate, and surrounded +at the distal end by a verticil of five stout, curved branches, and at the +pyramidal base by a corona of twelve to sixteen basal pores. Mouth armed +with a corona of twelve conical, vertical, spinulate teeth. + +_Dimensions._--Diameter of the shell 0.75, length of the spines 0.6. + +_Habitat._--South Pacific, Station 295, depth 1500 fathoms. + + +3. _Circostephanus polygonarius_, n. sp. + +Shell polyhedral, with sixty to eighty subregular, triangular, concave +faces, which are separated by prominent crests. From the elevated corners +of the polyhedron arise thirty to forty radial spines, which are longer +than the diameter of the shell, densely covered with curved bristles and +three-sided prismatic, with three spirally convoluted edges. Their distal +end is surrounded by a verticil of eight or nine curved branches, and their +pyramidal base by a corona of eight or nine basal pores. Mouth armed with a +corona of ten conical, vertical, spinulate teeth. + +_Dimensions._--Diameter of the shell 0.8, length of the spines 0.9. + +_Habitat._--South Pacific, Station 288, depth 2600 fathoms. + + + +Subfamily 2. HAECKELINIDA. + +_Definition._--#Circoporida# with dimpled spherical shell, not composed of +polygonal plates. The shell is covered with small roundish dimples, never +polyhedral, and the radial spines are simple, not branched, and usually not +regularly arranged. + + + +Genus 716. _Haeckeliana_, John Murray, 1879, _in schedulis_, Chall. Coll. + +_Definition._--#Circoporida# with spherical shell of a peculiar dimpled, +porcellanous structure, and with a variable number of simple radial +main-spines which are usually not regularly arranged. + +{1701}The genus _Haeckeliana_ comprises the spherical Circoporida, with +dimpled, porcellanous shell, which are widely distributed, but rather rare, +in depths between 2000 and 3000 fathoms. All the known species (six in +number) are very closely related, and though the extreme forms appear very +different in size and structure, they are so connected by a continuous +series of intermediate forms, that they may be regarded as varieties of a +single species, first observed by Dr. John Murray, and called by him +_Haeckeliana porcellana_. The number of radial spines may be from sixteen +to fifty-five, and is usually between thirty and forty. Each is surrounded +by a basal coronet of aspinal pores, usually five, more rarely four or six; +the number, however, is not constant in any one species. Each coronet is +armed with an outer ring of by-spines. The surface of the shell between the +coronets is dimpled. The mouth (Pl. 114, fig. 3) is about as large as a +corona, and also armed with a ring of by-spines. The structure of the thick +porcellanous shell and the radial spines is different from the other +Circoporida. + + +1. _Haeckeliana porcellana_, John Murray (Pl. 114, fig. 6). + + _Haeckeliana porcellana_, John Murray, 1879, _in schedulis_, Chall. Coll. + +Shell with forty to forty-five coronets, the majority of which have five +pores (more rarely four or six). Coronets broader than their intervals, and +twice as broad as the length of the by-spines. Dimples subcircular, of the +same breadth as the pores. Main-spines about as long as the radius. + +_Dimensions._--Diameter of the shell 0.37 to 0.42, of the coronets 0.06 to +0.07. + +_Habitat._--South Pacific, Stations 289 to 293, depth 2025 to 2550 fathoms. + + +2. _Haeckeliana maxima_, n. sp. (Pl. 114, fig. 5). + +Shell with fifty to fifty-five coronets, the majority of which have six +pores (more rarely five or seven). Coronets broader than their intervals, +and eight to ten times as broad as the length of the by-spines. Dimples +irregularly polygonal, of about the same breadth as the pores. Radial +main-spines about as long as the diameter of the shell. + +_Dimensions._--Diameter of the shell 0.5 to 0.52, of the coronets 0.08 to +0.09. + +_Habitat._--Equatorial Atlantic, Station 347, depth 2250 fathoms. + + +3. _Haeckeliana lamarckiana_, n. sp. (Pl. 114, fig. 4). + +Shell with thirty-five to forty coronets, the majority of which have five +pores (more rarely six or four). Coronets broader than their intervals; +each funnel-shaped pore on the inside with a circle of small conical +thorns. By-spines rudimentary or wanting. Dimples irregularly polygonal, +half as broad as the pores. Radial main-spines shorter than the radius. + +_Dimensions._--Diameter of the shell 0.38 to 0.45, of the coronets 0.06 to +0.07. + +_Habitat._--South Atlantic, Stations 318 to 333, depth 2000 to 2900 +fathoms. + + +{1702}4. _Haeckeliana murrayana_, Haeckel. + + _Challengeria_ sp., John Murray, 1876, Proc. Roy. Soc., vol. xxiv, pl. + xxiv. fig. 6. + +Shell with twenty to twenty-five coronets, the majority of which have five +pores (more rarely four or six). Coronets of about the same breadth as +their intervals, and twice as broad as the by-spines. Dimples subcircular, +of about the same breadth as the pores. Radial main-spines about as long as +the radius. + +_Dimensions._--Diameter of the shell 0.35 to 0.4, of the coronets 0.06 to +0.07. + +_Habitat._--Central Pacific, Stations 271 to 274, depth 2350 to 2750 +fathoms. + + +5. _Haeckeliana goetheana_, n. sp. (Pl. 114, fig. 3). + +Shell with sixteen to twenty coronets, the majority of which have four +pores (more rarely five and very rarely six). Coronets smaller than their +intervals. By-spines very short or rudimentary. Dimples subcircular, half +as broad as the pores. Radial main-spines shorter than the radius. + +_Dimensions._--Diameter of the shell 0.25 to 0.3, of the coronets 0.04 to +0.05. + +_Habitat._--North Pacific (south of Japan), Station 231, depth 2250 +fathoms. + + +6. _Haeckeliana darwiniana_, n. sp. (Pl. 114, figs. 1, 2). + +Shell with twenty-six to thirty-two coronets, the majority of which have +five pores (rarely four or six). Coronets smaller than their intervals and +than the length of the by-spines. Dimples subcircular, half as broad as the +pores, Radial main-spines longer than the radius. + +_Dimensions._--Diameter of the shell 0.30 to 0.42, of the coronets 0.07 to +0.08. + +_Habitat._--North Pacific (east of Japan), Stations 241 to 245, depth 2300 +to 2900 fathoms. + + + +Family LXXXII. #TUSCARORIDA#, n. fam. (Pl. 100). + +_Definition._--PHAEODARIA with an ovate, spindle-shaped, or nearly +spherical shell exhibiting a peculiar solid porcellanous structure; with a +few radial pores around the base of the hollow tubules, which are +symmetrically arranged around the main axis and the mouth. Surface of the +shell smooth or spiny, not tabulate nor panelled. Central capsule +excentric, placed in the aboral half of the shell-cavity. + +The #Tuscarorida#, and the preceding closely allied family, the +Circoporida, represent together a peculiar small group, which differs from +the other PHAEODARIA in the singular porcellanous structure of the +shell-wall, and may be called #Phaeocalpia#; their hollow radial spines are +distinguished by peculiar basal pores, forming a circle around their base. +The shell of the Tuscarorida is monaxonian, ovate, spindle-shaped {1703}or +nearly spherical, whilst in the Circoporida it is polyaxonian, spherical or +polyhedral; the hollow radial spines are arranged in the former around the +main axis, in the latter around the common central point. All #Phaeocalpia# +(the Tuscarorida as well as the Circoporida) are inhabitants of great +depths, usually between 2000 and 3000 fathoms. + +Though the number of Tuscarorida at present known is small (only three +genera, with ten species), they represent a very distinct and remarkable +family of PHAEODARIA, as well by their considerable size, as by the +peculiar arrangement of the radial spines and the structure of the +shell-wall, which in some species is more solid and thicker than in any +other Radiolaria. The diameter of the shell is always more than 1 mm., +usually between 1 and 2, and sometimes more than 3 mm. + +The dry shell of the Tuscarorida is not hyaline and transparent as is usual +in the other Radiolaria, but perfectly opaque, milk-white or +yellowish-white. This opacity is caused by innumerable very fine pores, +which everywhere pierce the thick, apparently solid, fundamental substance +of the shell-wall. Besides those very small pores, it is also pierced by a +certain number of larger pores, which are scattered at wide distances +(Narr. Chall. Exp., vol. i. pl. A, fig. 15_b_). These larger pores or +pore-channels have a diameter of about 0.01 mm., and pierce the shell-wall +either in a perpendicular or in an oblique direction. Very numerous +straight, simple, and thin needles, usually 0.1 to 0.2 mm. in length, +similar to the thin tangential needles of the Aulacanthida, are everywhere +scattered tangentially in the cement-like fundamental substance, which +seems to be a peculiar carbonic silicate; their axis is parallel to the +shell-surface. + +The general form of the shell is somewhat different in the three genera of +Tuscarorida; ovate or spherical in _Tuscarora_ and _Tuscarusa_, which bear +no caudal axial spine (Pl. 100, figs. 1-7), or sometimes three-sided +pyramidal (fig. 4); it is spindle-shaped in _Tuscaridium_, which bears on +the aboral pore an axial caudal spine (Pl. 100, fig. 8). In every case the +main axis of the shell, determining its monaxonian fundamental form, is +indicated by the mouth, which is placed in the oral pole of the main axis +and prolonged into a short tube or proboscis. + +The hollow apophyses, arising from the shell of the Tuscarorida, are always +cylindrical, long and thin tubules, the narrow cavity of which communicates +directly with the large shell-cavity. In the axis of the tubules lies a +thin axial chord or funicle, composed of a few (usually three or four) +siliceous threads which arise from bridges between the basal pores of the +apophyses, and are twisted together like the strands of a rope. The axial +funicle is connected with the thin wall of the tubular apophyses by +innumerable very thin radial beams, perpendicular to the axis (Pl. 100, +fig. 3_a_, 5_b_). The surface of the apophyses is almost constantly covered +with numerous small bristles or spines, which are usually curved and +directed towards their distal ends. + +_Tuscarora_ (Pl. 100, figs. 1-6) exhibits two different groups of +apophyses, which may be distinguished according to their different position +and direction as "circoral {1704}teeth" and "aboral feet"; the teeth +immediately surround the opening of the mouth, whilst the feet are remote +from it and usually placed in the aboral half of the body, more rarely in +the equator or in the oral half. The general form and structure are the +same in both groups of apophyses, but their position and direction is +different; the circoral teeth are directed forwards, often parallel (at the +base at least), while the aboral feet are either divergent and directed +backwards, or they diverge forwards in the basal part, then form a large +arch, and finally curve backwards. + +The number of the aboral feet, and their position relative to the circoral +teeth, are different but probably constant in each single species, and +serve, in the first place, for the distinction of genera and species. +_Tuscarora_ (in restricted sense) (Pl. 100, figs. 1-6), has constantly +three feet (comparable to the three cortinar feet of the tripodal +NASSELLARIA); _Tuscarusa_ (Pl. 100, fig. 7) has four feet, opposite in +pairs and forming a regular cross; _Tuscaridium_, finally (Pl. 100, fig. +8), has only one foot, which is situated in the main axis, on its aboral +pole, and may therefore be called a caudal spine. + +The number of the circoral teeth varies from two to four, and is usually +three. Originally these three teeth alternate regularly with the three +aboral feet, so that the latter may be regarded as perradial, the former as +interradial (Pl. 100, figs. 1-4). The proportion of the number of each +group of apophyses in the different species is synoptically shown in the +following table:-- + + a = Depth in Fathoms. + b = Challenger Station. + c = Length of the Shell. + d = Breadth of the Shell. + e = Number of Feet. + f = Number of Pedal Pores. + g = Number of Teeth. + h = Number of Dental Pores. + +------------------------------+------+-----+-----+-----+---+---+---+---+ + | | a | b | c | d | e | f | g | h | + +------------------------------+------+-----+-----+-----+---+---+---+---+ + | 1. _Tuscarora bisternaria_, | 3000 | 264 | 2.0 | 1.5 | 3 | 8 | 3 | 8 | + | 2. " _murrayi_, | 2000 | 295 | 2.5 | 1.5 | 3 | 3 | 3 | 3 | + | 3. " _wyvillei_, | 2250 | 291 | 1.5 | 1.4 | 3 | 4 | 3 | 4 | + | 4. " _tetrahedra_, | 2450 | 348 | 2.5 | 2.0 | 3 | 4 | 3 | 3 | + | 5. " _tubulosa_, | 3000 | 249 | 1.4 | 1.2 | 3 | 4 | 2 | 3 | + | 6. " _porcellana_, | 2650 | 325 | 1.5 | 1.3 | 3 | 4 | 2 | 4 | + | 7. " _belknapii_, | 2025 | 293 | 2.5 | 1.5 | 3 | 3 | 4 | 2 | + | 8. _Tuscarusa medusa_, | 3125 | 253 | 1.2 | 1.0 | 4 | 4 | 2 | 2 | + | 9. _Tuscaridium cygneum_, | 3050 | 250 | 3.2 | 1.6 | 1 | 2 | 4 | 4 | + |10. " _lithornithium_, | 3000 | 264 | 3.6 | 1.8 | 1 | 4 | 4 | 6 | + +------------------------------+------+-----+-----+-----+---+---+---+---+ + +The base of the apophyses in all Tuscarorida is inflated, conical, and +pierced by a small number of large ovate pores, the typical "basal pores," +which occur also in the closely allied Circoporida. The number of these +basal pores varies from two to eight, and is usually three or four; it +never becomes in this family so great as in the Circoporida, where each +circle of pores is often composed of sixteen to twenty-four or more basal +pores. The number seems to be rather constant in each single species, as +may be seen in the preceding Table. The pedal pores (on the base of the +aboral feet) are usually larger than the dental pores (on the base of the +circoral teeth). Their form is {1705}usually irregularly ovate or +triangular; their outer aperture is armed with spines or bristles, which +are commonly larger than in the other parts of the apophyses. + +The mouth of the shell varies in form, according to the number and +arrangement of the teeth on its corners. It is therefore a narrow +transverse fissure, with two broad opposite lips and two corners, in the +bidental forms (Pl. 100, figs. 5, 7), triangular in the tridental species +(figs. 1-4), quadrangular or square in the quadridental species, _Tuscarora +belknapii_ (Narr. Chall. Exp., _loc. cit._, pl. A, fig. 15). The singular +genus _Tuscaridium_ (fig. 8) exhibits four teeth, which are nearly +horizontally divergent in two pairs, a dorsal and a ventral pair +(corresponding in position to the four feet of _Tuscarusa_, fig. 7); the +mouth is here prolonged into a cylindrical, spinulate proboscis, which is +curved towards the ventral face of the shell (fig. 8). + +The _central capsule_ of the Tuscarorida is kidney-shaped or spheroidal, +scarcely half as large as the dark olive-green phaeodium, which surrounds +its anterior (oral) face. Usually the capsule and the phaeodium together +fill up the aboral half of the shell-cavity, and are separated from its +walls by the calymma. The latter is pierced by numerous branched and +reticulately anastomosing pseudopodia, which arise from the matrix +enveloping the capsule, and pass over into a thin layer of sarcode, +adjacent to the inner surface of the shell. The astropyle or the +main-opening of the central capsule exhibits the usual radiate operculum +and tubular proboscis of the PHAEODARIA (Pl. 115, fig. 3), and is directed +towards the mouth of the shell. The number of the parapylae or accessory +openings seems to be variable in this family, and to correspond to the +number of radial feet which arise from the shell. Therefore _Tuscaridium_ +possesses only one parapyle, which is diametrically opposite to the mouth, +lies on the aboral pole of the capsule, and is directed towards the single +caudal tube. _Tuscarora_ seems to have three parapylae, corresponding to +the three radial feet, and _Tuscarusa_ probably has four parapylae, +directed towards its four radial feet; in the latter genus, however, the +capsule was not observed (the shell being empty); and in the other +Tuscarorida this important and difficult anatomical question must be solved +by further accurate examinations. + +The nucleus is nearly half as large as the central capsule, ellipsoidal, +and contains numerous nucleoli. In one specimen of _Tuscarora belknapii_ I +observed two nuclei in the central capsule, and in another specimen of the +same species John Murray observed two central capsules (figured by him in +the Narr. Chall. Exp., vol i. pl. A, fig. 15). + +_Synopsis of the Genera of Tuscarorida._ + + Three equidistant aboral radial feet, 717. _Tuscarora_. + Four equidistant aboral radial feet, 718. _Tuscarusa_. + One single aboral foot or terminal spine, 719. _Tuscaridium_. + + + +{1706}Genus 717. _Tuscarora_,[333] John Murray, 1876, _in schedulis_, +Chall. Coll. + +_Definition._--#Tuscarorida# with three radial aboral feet, and a variable +number of circoral teeth. + +The genus _Tuscarora_ comprises seven of the ten observed species of +Tuscarorida, all seven agreeing in the possession of three perradial feet, +which alternate originally (in four species), with three interradial teeth +surrounding the mouth. The latter is armed in two other species with two +teeth, and in one species with four teeth (compare above, p. 1704). The +three perradial feet have a similar position as in the tripodal +NASSELLARIA, so that they may be distinguished as an odd caudal foot and +two paired lateral feet. + + + +Subgenus 1. _Tuscarantha_, Haeckel. + +_Definition._--Shell with three perradial equidistant feet and three +interradial equidistant circoral teeth, alternating regularly with the +former. + + +1. _Tuscarora bisternaria_, John Murray (Pl. 100, figs. 1, 1_a_). + + _Tuscarora bisternaria_, John Murray, 1879, _in litteris_, Narr. Chall. + Exp., vol. i. p. 226, pl. A, figs. 16, 16_a._ + +Shell subspherical, with three lateral perradial feet in the equatorial +zone, and three basal interradial teeth around the mouth, alternating +regularly with the former. The three lateral feet arise either in the +equator itself or a little above it, and are nearly horizontally expanded, +descending a little towards the aboral pole. They are straight, +cylindrical, twice to four times as long as the shell, geniculate at the +inflated base, and covered with small thorns. A circle of six to eight +basal pores in the base of each foot. The narrow mouth is triangular, +surrounded by the thorny, inflated, subspherical bases of the three long, +cylindrical, diverging, thorny teeth, which ascend obliquely and are longer +than the shell; each tooth exhibits in the upper part of the inflated base +a corona of eight to ten ovate holes. + +_Dimensions._--Length of the shell 2.0, breadth 1.5. + +_Habitat._--Central Pacific, Station 264, depth 3000 fathoms. + + +2. _Tuscarora murrayi_, n. sp. (Pl. 100, fig. 2). John Murray, 1876, L. N. +27, pl. 24, fig. 4. + +Shell pear-shaped, with three circoral perradial feet in the upper third +and three basal interradial teeth around the mouth. The three lateral feet +are thin, cylindrical, arcuate, very bristly, arise immediately beyond the +narrow tubular peristome, and ascend obliquely nearly to the height of the +mouth; then they are curved downwards in a large arc, three to four times +as long as {1707}the shell. The tubular peristome is about half as long as +the shell, bottle-shaped, nearly three-sided prismatic, and bears three +very long spinulate teeth, which in the lower half are parallel, in the +upper slightly curved and diverging, at the base pear-shaped. Three ovate +basal pores in the inflated base of each foot and each tooth. + +_Dimensions._--Length of the shell 2.5, breadth 1.5. + +_Habitat._--South Pacific, Station 295, depth 1500 fathoms. + + +3. _Tuscarora wyvillei_, n. sp. (Pl. 100, figs. 3, 3_a_-3_c_). + +Shell subspherical, pellucid, thinner and more fragile than in the other +species of the genus, with three aboral perradial feet in the lower third, +and three interradial teeth around the wide mouth. The three feet are +straight, conical, widely divergent, shorter than the shell, and arise from +its lower third; on the inflated base of each four small ovate pores. The +three teeth, alternating with them, are straight, cylindrical, arise from +the margin of the mouth and diverge obliquely upwards. On the base of each +foot four opposite cordate pores of very unequal size. + +_Dimensions._--Length of the shell 1.5, breadth 1.4. + +_Habitat._--South Pacific, Station 291, depth 2250 fathoms. + + +4. _Tuscarora tetrahedra_, John Murray (Pl. 100, figs. 4, 4_a_). + + _Tuscarora tetrahedra_, John Murray, 1879, _in litteris_, Narr. Chall. + Exp., vol. i. p. 226, pl. A, fig. 19. + +Shell tetrahedral or three-sided pyramidal, with three perradial basal +feet, and three alternate, interradial, circoral teeth. The three rounded +edges of the pyramid are prolonged directly over the aboral base into the +three short, divergent, conical, basal feet, which are smooth and scarcely +one-fourth as long as the shell. The base of each foot is pierced by four +small crossed pedal pores. The narrow mouth, on the apex of the pyramid, is +surrounded by three short and broad, triangular, spinulate teeth, each of +which bears three slender, triangular, dental pores. + +_Dimensions._--Length of the shell 2.5, breadth 2.0. + +_Habitat._--Tropical Atlantic, Station 348, depth 2450 fathoms. + + + +Subgenus 2. _Tuscaretta_, Haeckel. + +_Definition._--Shell with three perradial equidistant feet, and with two +circoral teeth, which are opposite in the radius of the odd dorsal foot; +therefore a dorsal and a ventral tooth. + + +5. _Tuscarora tubulosa_, John Murray (Pl. 100, figs. 5, 5_a_, 5_b_). + + _Tuscarora tubulosa_, John Murray, 1879, _in litteris_, Narr. Chall. + Exp., vol. i. p. 226, pl. A, fig. 17. + +Shell subspherical, with three lateral perradial feet on the upper half of +the shell (above the equator), and two parallel vertical teeth on the +mouth. The three feet arise between the upper and {1708}the middle third of +the shell, diverge upwards, and are slightly arcuate, covered with numerous +curved spines. Their base is pierced by four pedal pores. The peristome is +a narrow sagittal fissure, placed in the radius of the odd or dorsal foot, +and bears two opposite teeth on its two corners. The teeth are cylindrical, +longer than the shell, covered with curved spines, and ascend in a parallel +and vertical manner; each is perforated at the base by three large dental +pores. + +_Dimensions._--Length of the shell 1.4, breadth 1.2. + +_Habitat._--North Pacific, Stations 244 to 250, depth 2050 to 3050 fathoms. + + +6. _Tuscarora porcellana_, John Murray (Pl. 100, figs. 6_a_, 6_b_). + + _Tuscarora porcellana_, John Murray, 1819, _in litteris_, Narr. Chall. + Exp., pl. A, fig. 18. + +Shell pear-shaped, with three lateral perradial feet in the lower half of +the shell, and two parallel vertical teeth on the mouth. The three lateral +feet arise between the middle and the lower third of the shell, are +straight, cylindrical, spinulate, about as long as the shell and diverge +downwards; their base is pierced by four ovate pedal pores. The two +parallel and vertical teeth are straight, shorter than half the shell, and +opposite in the sagittal plane, on the two corners of the narrow mouth, in +the radius of the dorsal odd foot. The base of each tooth exhibits four +cordate dental pores. + +_Dimensions._--Length of the shell 1.5, breadth 1.3. + +_Habitat._--South Atlantic, Station 325, depth 2650 fathoms. + + + +Subgenus 3. _Tuscarilla_, Haeckel. + +_Definition._--Shell with three perradial equidistant feet, and with four +crossed equidistant teeth around the mouth. + + +7. _Tuscarora belknapii_, John Murray. + + _Tuscarora belknapii_, John Murray, 1879, _in litteris_, Narr. Chall. + Exp., vol. i. p. 226, pl. A, figs. 15, 15_a_-15_d._ + +Shell pear-shaped, with three lateral perradial feet in the upper third, +and four crossed teeth around the mouth. The three arcuate feet are thin, +cylindrical, covered with small curved thorns, and arise at the base of the +peristome, between the upper and middle third of the shell; they ascend +diverging to the height of the mouth, and are then curved downwards in a +large arc, twice to three times as long as the shell. The base of each foot +is dilated and pierced by three pedal pores. The four thin and long teeth +of the peristome are similar to the feet, ascend in a slightly diverging +manner, and are so placed that two opposite lie in the sagittal plane (or +in the radius of the dorsal odd foot), whilst the two others are opposite +in the frontal plane (perpendicular to the former). The base of each tooth +exhibits two large ovate dental pores. + +_Dimensions._--Length of the shell 2.5, breadth 1.5. + +_Habitat._--South Pacific, Station 293, depth 2025 fathoms. + + + +{1709}Genus 718. _Tuscarusa_,[334] n. gen. + +_Definition._--#Tuscarorida# with four radial aboral feet and a variable +number of circoral teeth. + +The genus _Tuscarusa_ differs from the preceding closely allied _Tuscarora_ +in the possession of four radial feet instead of three. The mouth of the +single observed species is a narrow sagittal fissure, and armed with two +opposite teeth (a dorsal and a ventral, as in the subgenus _Tuscaretta_). +The four lateral feet form a cross, and lie opposite in pairs, in two +diagonals of the square, which is bisected by the sagittal mouth. + + +1. _Tuscarusa medusa_, n. sp. (Pl. 100, figs. 7, 7_a_). + +Shell ovate, with four crossed lateral feet in the upper third, and with +two opposite teeth around the mouth. The four feet are opposite in pairs in +two diameters of the shell, perpendicular one to another, and arise between +the upper and middle third of the shell; they are thin, cylindrical, +spinulate, arcuate, and ascend to the height of the mouth diverging +upwards; then they are curved downwards in a large arc. They lie in the +diagonals of the square, which is halved by the narrow and long fissure of +the mouth. This lies in the original sagittal plane, and from its two +corners arise the two opposite teeth (a dorsal and a ventral), diverging +upwards, cylindrical and slightly curved. The base of each foot is pierced +by four pedal pores, of each tooth by two dental pores. + +_Dimensions._--Length of the shell 1.2, breadth 1.0. + +_Habitat._--North Pacific, Station 253, depth 3125 fathoms. + + + +Genus 719. _Tuscaridium_,[335] n. gen. + +_Definition._--#Tuscarorida# without radial aboral feet, but with a +terminal axial caudal foot, and a variable number of circoral teeth. + +The genus _Tuscaridium_, comprising two closely allied species, differs +from the two preceding genera of Tuscarorida in the absence of lateral +radial feet, which are represented by a single large caudal spine placed in +the main axis of the shell, at its aboral pole. The shell is therefore +spindle-shaped, and not ovate or subspherical, as in the two other genera. +It reaches in the two observed species a length of more than 3 mm. + + +1. _Tuscaridium cygneum_, Haeckel. + + _Tuscarora cygnea_, John Murray, 1879, in litteris, Narr. Chall. Exp., + vol. i. p. 226, pl. A, fig. 20. + +Shell spindle-shaped, twice as long as broad (in the transverse section +circular), equally tapering towards both poles of the main axis. The aboral +pole bears a thin, cylindrical, straight, caudal {1710}spine, placed in the +prolongation of the main axis, and about half as long as the shell. Its +base is pierced by two large opposite pedal pores. The anterior or oral +pole bears a cylindrical peristome, similar to a bird's head, and curved +towards the ventral face; on both sides of its neck (at right and left) a +series of three or four irregular, ovate, buccal holes. The neck bears four +cylindrical, spinulate, radial tubes (two on each side), crossed nearly +horizontally, and placed in two diagonal planes perpendicular one to +another; these planes correspond to those in which the four feet of +_Tuscarusa medusa_ lie. The base of each tube is pierced by four dental +pores. + +_Dimensions._--Length of the shell 3.2, breadth 1.6. + +_Habitat._--North Pacific, Station 250, depth 3050 fathoms. + + +2. _Tuscaridium lithornithium_, n. sp. (Pl. 100, figs. 8, 8_a_, 8_b_). + +Shell spindle-shaped, twice as long as broad, very similar to the preceding +closely allied species. It differs from the latter in the following +characters:--The curved proboscis of the peristome is broader and more +spiny. The four radial tubes of the mouth and the terminal caudal spine are +very spiny (in the preceding species nearly smooth). The number of buccal +holes (six to eight on each side of the mouth) is twice as great as in the +former. Each circoral tube is pierced at the base by six or eight (in the +former by four pores), and the base of the caudal spine exhibits a cross of +four pores (in _Tuscaridium cygneum_ only two pores). + +_Dimensions._--Length of the shell 3.6, breadth 1.8. + +_Habitat._--North Pacific, Station 264, depth 3000 fathoms. + + +---- + + +Order IV. PHAEOCONCHIA, Haeckel, 1879. + +_Definition._--PHAEODARIA with a bivalved lattice-shell, composed of two +free opposite valves (a dorsal and a ventral), between which the central +capsule is enclosed. + + + +Family LXXXIII. #CONCHARIDA#, Haeckel, 1879 (Pls. 123-125). + + _Concharida_, Haeckel, 1879, Sitzungsb. med.-nat. Gesellsch. Jena, Dec. + 12, p. 6. + +_Definition._--PHAEODARIA with a bivalved lattice-shell, which is spherical +or lenticular, and composed of two equal or unequal boat-shaped valves, a +dorsal and a ventral. The valves bear neither an apical latticed cupola or +galea, nor hollow radial tubes. The central capsule is placed in the aboral +half of the shell-cavity, and so enclosed between both valves, that its +three openings lie in the open frontal fissure between them (the astropyle +on the oral pole of the main axis, the two parapylae on both sides of its +aboral pole, at right and left). + +{1711}The family #Concharida# and the two following closely allied +families, the Coelodendrida and Coelographida, compose together the most +remarkable and interesting suborder of #Phaeoconchia# (or "PHAEODARIA +bivalva"), differing from all the other Radiolaria in the possession of a +bivalved lattice-shell, composed of two separate valves, like the shell of +a Brachiopod. The central capsule is so enclosed between the two +fenestrated valves that its three openings lie in the horizontal open +(frontal) fissure between them, the astropyle or main-opening on the oral +pole of the main axis; the two secondary openings or parapylae on the two +sides of its aboral pole, at right and left. The plane in which the three +openings lie is therefore the frontal plane, dividing the entire body into +a dorsal and a ventral half. The two valves, accordingly, must be +considered as dorsal and ventral valves (as in the Brachiopoda), and the +symmetrical halves of each valve as right and left. These halves may be +always easily distinguished, since the oral pole of each valve is +constantly different from the aboral pole. The voluminous phaeodium always +lies in the oral half, and the central capsule in the aboral half of the +shell-cavity, whilst the calymma encloses the whole shell. + +The Concharida differ from the other two families of bivalved PHAEODARIA in +the absence of the apical galeas, and the branched hollow tubes arising +from them. Each of these two cupolas, which are at the opposite poles of +the sagittal axis (one cupola on the apex of each valve), is in the +Coelographida connected by a simple or double frenulum with a peculiar +rhinocanna, or an open nasal tube directed towards the mouth; whilst the +cupolas of the Coelodendrida possess neither a rhinocanna nor a frenulum. +The three families of #Phaeoconchia# may therefore represent a +phylogenetical series, the common root of which are the Concharida. From +these are developed the Coelodendrida by development of an apical cupola or +galea on each valve, and of hollow radial tubes arising from it; whilst the +Coelographida are developed from the latter by production of a rhinocanna +on the base of each cupola, and of one or two frenula connecting the former +with the latter. + +All the Concharida described in the following pages (seven genera and +thirty species), are perfectly new to science, and not a single form of +this interesting family was known before the explorations of the +Challenger. Some species (mainly of the genera _Conchidium_ and +_Conchopsis_) are by no means rare, and are found in great numbers at some +stations of the tropical seas (in the Pacific as well as in the Atlantic). +All described species are closely allied, agree in the majority of +characters, and are easy to distinguish from all the other Radiolaria. Some +few forms of Concharida, however, form a direct passage to the +Coelodendrida. + +Regarding the probable origin of the Concharida (and therefore also of all +other #Phaeoconchia# derived from the latter), two different hypotheses are +possible. They have either been derived directly from the skeletonless +_Phaeodina_, by development of a bivalved lattice-shell; or they may be +derived from PHAEODARIA with a simple {1712}spherical lattice-shell +(Castanellida), by the halving of this latter, or its splitting into two +hemispherical valves; the former hypothesis is more probable than the +latter. + +The two valves of the lattice-shell (Pls. 123-126) must in the Concharida +(as in all other #Phaeoconchia#) be distinguished as dorsal and ventral, +and may therefore be compared with the two valves of the Brachiopoda, not +with those of the Lamellibranchia. This important morphological distinction +is expressed by the constant position of the central capsule within the +shell-cavity. The capsule always exhibits the character of the "TRIPYLEA" +and has three tubular openings, placed in the frontal or lateral plane of +the unicellular body. In the same plane lies the open frontal fissure +between the two valves, and the three openings are so disposed in it that +the large anterior main-opening (or the astropyle) is placed on the oral +pole of the main axis, whilst the two accessory small lateral openings or +parapylae are placed on both sides of the aboral pole, at the right and +left. Therefore in a dorsal or ventral view all three openings are visible +(Pl. 123, figs. 1, 8_a_); in the usual lateral view, however, from the +right or left side, only two openings are visible, the astropyle on the +anterior, and one parapyle (right or left) near the posterior pole of the +main axis (Pl. 123, figs. 8, 9; Pl. 124, figs. 6, 10). The posterior view +(from the aboral pole) shows the two parapylae, at right and left; in the +anterior view (from the oral pole) the astropyle may be visible, but +usually it is completely hidden in the dark voluminous phaeodium. This +latter envelops sometimes nearly the whole capsule as an opaque +conglomeration of green or brown phaeodella (Pl. 123, figs. 8, 9); but +usually the phaeodium fills up the anterior (oral) half of the +shell-cavity, whilst the capsule occupies the posterior (aboral) half (Pl. +124, figs. 6, 10). + +The dorsal shell-valve is in almost all PHAEODARIA smaller or somewhat +different in shape from the ventral valve, and this difference is often +very striking (Pl. 124, figs. 3-16); but in a few species both valves are +so similar, that I could not discover any certain difference. This equality +of the two valves occurs mainly in those Concharida which pass over into +the Coelodendrida; in these latter as well as in the Coelographida, both +valves are usually equal in size and form. Whilst the main axis (or the +longitudinal axis of the body) in the two latter families of #Phaeoconchia# +seems to be normally vertical (in the living and freely floating body), in +the living Concharida it is probably horizontal, so that the larger and +heavier ventral valve lies below the smaller and lighter dorsal valve. + +The geometrical fundamental form of the body is therefore in the Concharida +dipleural or bilaterally symmetrical, and we distinguish in it the same +three dimensive axes, as in all other dipleural forms. On the anterior or +oral pole of the main axis (or longitudinal axis) lies the mouth of the +shell, and behind it the phaeodium; on the opposite posterior or aboral +pole lies the hinge of the shell (comparable to the shell-hinge of the +Brachiopoda) and in front of it the central capsule. The sagittal (or +{1713}dorso-ventral) axis, determining the height of the shell, has on its +dorsal (or upper) pole the apex or highest point of the dorsal valve, on +its ventral (or lower) pole the apex or lowest point of the ventral valve. +The two poles of the frontal (lateral or transverse) axis are equal and are +determined by the two parapylae of the capsule, and the corresponding +points of the shell-fissure between both valves. Usually the main-axis is +the longest, the frontal axis the shortest, and between both the sagittal +axis. + +In regard to the three dimensive planes which are determined by these three +axes, perpendicular to one another, they are rarely of nearly equal size +(as in some subspherical species), usually the sagittal plane (separating +the right and left halves of the body) is the largest; the cinctural or +equatorial plane (separating oral and aboral halves) is the smallest, and +the frontal or lateral plane (separating dorsal and ventral halves) is +intermediate in size. The relation of the three perimeters of these three +planes corresponds to that proportion; the sagittal perimeter (in which the +keel of the compressed valves lies) is the largest; the cinctural or +equatorial perimeter (separating the anterior phaeodium and the posterior +central capsule) is the smallest, and the frontal or lateral perimeter (in +which the fissure between the valves lies) is intermediate in size. + +The general form of the single valves is very varied in the different +species, in the majority boat-shaped or hat-shaped, more or less laterally +compressed, in a few forms hemispherical. In _Conchopsis_ (Pl. 125) and +_Conchoceras_ (Pl. 124, figs. 15, 16) the lateral parts of the valves +(right and left) are vaulted, whilst their median parts are so strongly +compressed that they form a sharp sagittal keel, and then the shell in the +dorsal or ventral view appears spindle-shaped (Pl. 123, fig. 8_a_; Pl. 125, +fig. 8). Often the frontal margins of the valves are somewhat constricted +(Pl. 124, fig. 7). + +The junction between the two valves of the shell is always loose, but not +so loose as in the two following families. In the Coelodendrida and +Coelographida the two valves are either perfectly free and separated by a +frontal zone of jelly, or in very loose contact on the frontal margins. In +the Concharida, however, the margins of both valves seem to be usually in +contact, and their connection is effected in a double way. In the subfamily +Conchasmida (comprising the genera _Concharium_ and _Conchasma_, Pl. 123, +figs. 1-6) the lateral margins of both valves are smooth, not dentated, and +fit one into another like the two parts of a box, or like the two valves of +a Diatom (_Navicula_). In the second subfamily, however, Conchopsida +(comprising the five other genera, Pls. 124, 125), the lateral margins of +the valves are dentate, usually provided with a series of numerous strong +conical teeth, and the teeth of both valves so catch into one another, that +their union is rather firm (like the margin of the shells of _Tridacna_, +_Pecten_, and other Lamellibranchiata). Besides, a more solid junction is +often effected on the posterior or aboral part of the margins, which we +shall call the hinge. Here often peculiar strong teeth catch one into +another, and in the majority of species {1714}two aboral spines are +developed, the caudal horns (a dorsal and a ventral); these are very large +in _Conchoceras_ (Pl. 124, figs. 15, 16). But a peculiar and most +interesting kind of junction is effected in some Concharida by a true +ligament between the valves (Pl. 123, figs. 8, 9; Pl. 125, fig. 2). This +ligament is always placed on the aboral hinge, is of dark brown colour, and +is not dissolved by mineral acids unless long applied. It may preserve the +connection of the posterior parts of both valves, when their anterior parts +are removed one from another, just as in the Brachiopoda. I observed this +interesting ligament mainly in the genus _Conchopsis_, but not in all +species, and it is not yet certain whether it is a constant organ in these +and some other Concharida. + +In the majority of Concharida the lateral margins of the two valves project +slightly inwards into the cavity, and in some species of _Conchopsis_ these +inner borders are so broadened that they form a broad, horizontal, +fenestrated inner shelf, comparable to the deck of a boat or to the velum +of the Hydromedusae or Craspedotae (Pl. 125, fig. 9). In this case the +velum surrounds the ovate aperture through which the two lobes of the +central capsule (dorsal and ventral) enter into the cavity of both valves. + +The mouth of the shell lies on the oral pole of the main axis, and is +therefore opposed to the aboral hinge. The two valves are here usually more +or less emarginate, so as to form a transverse mouth with an upper and a +lower lip (Pl. 124, figs. 6, 7, 11). The form of these two lips is often +very different and characteristic of particular species (Pl. 124, figs. 3, +15, 16). The mouth remains in many species constantly open, even when the +frontal fissure is closed (figs. 7, 16). Since the centre of the shell +mouth lies in the prolongation of the proboscis arising from the operculum +of the central capsule, probably the main stream of sarcode, issuing from +the latter, becomes protruded by the former. + +Apophyses of the shell (besides the teeth of the margins) are completely +wanting in three genera, _Concharium_, _Conchellium_, and _Conchopsis_ (Pl. +123, figs. 1-4, 7; Pl. 125). The four other genera possess free apophyses +or spines, which we call horns. They are probably important as the +beginnings of those large hollow tubes which are characteristic of the two +following families, Coelodendrida and Coelographida. We distinguish two +different forms of horns, apical horns on the poles of the sagittal axis, +and caudal horns on the aboral pole of the main axis; the former probably +correspond to the sagittal tubes and the latter to the caudal tubes of the +two following families. Apical horns are found in a single genus only, +_Conchonia_ (Pl. 124, figs. 10-14). Here either on one pole or on poles of +the sagittal axis a horn is developed, usually curved backwards. Sometimes +the base of this conical horn is inflated and fenestrated, and may +represent the beginning of the formation of the galea or apical cupola of +the Coelodendrida. + +The two caudal horns are opposite on the aboral hinge of the shell, one +arising from the posterior end of each valve. Usually they are short and +thick, pyramidal, the {1715}ventral horn larger than the dorsal (Pl. 124, +figs. 3, 6). Rarely the two caudal horns are fenestrated at the base and +reach a considerable size, as in _Conchoceras_ (Pl. 124, figs. 15, 16). + +The walls of the bivalved shell usually exhibit in the Concharida a rather +solid shape and regular structure, with an elegant network of regularly +arranged pores. But in some species the walls of the shell become very thin +and fragile, and assume the same shape (with very irregular network), as in +the Coelodendrida and Coelographida. The pores are usually small and +numerous, circular, often hexagonally framed (Pl. 125, figs. 4-6). They +pierce the thick shell-wall either in a radial or in an oblique direction. +Sometimes each pore is armed with six radial teeth (Pl. 123, fig. 7_a_). At +other times each pore represents an oblique ampullaceous canal, dilated in +its middle part, with two narrow openings (Pl. 125, figs. 5_a_, _b_, _c_, +6). The pores are so arranged in the majority of species that they form +regular curved series, which are separated by prominent crests, and +converge towards the poles of the main axis. Usually the marginal pores +(along the frontal margin of the valves) are much smaller (compare Pls. +123-125). + +The _central capsule_ of the Concharida, very well preserved in numerous +specimens of the Challenger collection, constantly possesses the same +situation and structure. It is always enclosed in the aboral or posterior +half of the shell-cavity, whilst the oral or anterior half is filled up by +the phaeodium. The free spaces between both and between the inner surface +of the shell are completely filled up by the jelly of the calymma, which +also covers the whole shell as a thin outer jelly-envelope. The form of the +central capsule is sometimes nearly spherical, usually somewhat compressed +in the direction of the main axis, and sometimes also in the direction of +the frontal axis (Pl. 123, figs. 1-9). In some species it becomes bilobed, +with an upper dorsal and a lower ventral lobe, and in some others it +becomes triangular (Pl. 125, fig. 7). Its two membranes (inner and outer) +are often separated by a broad colourless interval, containing a clear +fluid or jelly (Pl. 123, figs. 8, 9). The nucleus is usually about half as +large as the central capsule and ellipsoidal, its longer axis lying in the +sagittal diameter of the body. Several specimens (of different genera) +contained two separate nuclei, one placed in the dorsal, the other in the +ventral half of the capsule (Pl. 124, fig. 6). This duplication of the +nucleus is probably the preparation for the division of the capsule. The +division will be probably effected in the frontal plane, so that each half +of the bisected capsule gets one nucleus and one valve, and the other valve +becomes newly formed (in a way similar to that in the bivalved +Diatomaceae). The astropyle, or the main-opening of the capsule, is closed +by a radiate operculum, from which arises a tubular proboscis; this lies in +the main axis of the body, is directed towards the anterior mouth of the +shell, and surrounded by the phaeodium. The two shorter tubes of the paired +parapylae, or the accessory lateral openings, lie on the posterior or +caudal side of {1716}the capsule, at right and left, and are directed half +backwards, half outwards (towards the frontal fissure between the valves, +Pl. 123, figs. 1, 8_a_). + +The phaeodium exhibits in all Concharida the same characteristic shape, and +represents a dark conglomeration of phaeodellae, filling up the anterior or +oral half of the shell-cavity. Usually it is bilobed, divided into a dorsal +and a ventral lobe or wing, which fills up the corresponding valve of the +shell (Pl. 123, figs. 8, 9). The phaeodium is commonly more voluminous than +the capsule, and surrounds its anterior half, more rarely it encloses +nearly the entire capsule (Pl. 124, figs. 6, 10). Its colour is usually +olive, sometimes more greenish, at other times more brownish, in some +species nearly black. The phaeodellae, or the roundish granules which +compose the phaeodium, exhibit the same shape as in all other PHAEODARIA +(compare above, p. 1535). Sometimes peculiar rather oblong nucleated cells +are scattered in great numbers between the phaeodellae, probably parasites +or symbiontes (Pl. 123, figs. 7-9, 9_a_). + +_Synopsis of the Genera of Concharida._ + + ------------------------------------------------------------------------- + I. Subfamily Conchasmida. + Lateral edges of the two valves smooth, without teeth. + ------------------------------------------------------------------------- + { Aboral hinge without + Valves without sagittal { horns, 720. _Concharium_. + keel, nearly hemispherical { + or slightly compressed. { Aboral hinge with two + { horns (one on each + { valve), 721. _Conchasma_. + ------------------------------------------------------------------------- + II. Subfamily Conchopsida. + Lateral edges of the two valves dentate, with a series of prominent + teeth on both sides. The teeth of both valves catch one into another. + ------------------------------------------------------------------------- + { Aboral hinge without + { horns, 722. _Conchellium_. + { + Valves without sagittal { Aboral hinge with two + keel, nearly hemispherical { horns. No apical horn, 723. _Conchidium_. + or slightly compressed. { + { Aboral hinge with two + { horns. Apex also with + { a horn, 724. _Conchonia_. + + { Aboral hinge without + Valves with a sharp { horns, 725. _Conchopsis_. + sagittal keel, strongly { + compressed on both sides, { Aboral hinge with two + boat-shaped. { horns (one on each + { valve). 726. _Conchoceras_. + + + +Subfamily 1. CONCHASMIDA, Haeckel. + +_Definition._--#Concharida# with the lateral margins of the two valves +smooth, without interlocking teeth. + + + +Genus 720. _Concharium_,[336] Haeckel, 1879, Sitzungsb. med.-nat. +Gesellsch. Jena, Dec. 12, p. 6. + +_Definition._--#Concharida# with the lateral margins of the valves smooth, +without sagittal keel and without horns on the hinge. + +{1717}The genus _Concharium_ is the simplest and the most primitive form of +all Concharida; it may be regarded as the common ancestral form of the +whole family. The entire shell is usually almost spherical, without horns +or teeth, and may be regarded as a _Castanella_ which is bisected or broken +into two equal hemispherical halves. The lateral margins of the two +hemispherical valves are smooth, without teeth, and catch one into the +other like the two valves of a Diatom, or the two halves of a bivalved box. +_Concharium_ agrees in this simple shape of the frontal margins with the +following genus _Conchasma_, and represents with it the small subfamily +Conchasmida. + + +1. _Concharium bivalvum_, n. sp. (Pl. 123, figs. 2, 2_a_). + +Shell spherical, smooth. Diameter in all directions nearly the same. +Borders of the two hemispherical valves circular, smooth, about twice as +broad as the pores. In the half frontal perimeter of the shell (along the +right and the left border of each valve) twenty-two to twenty-four pores, +in the half sagittal perimeter (in the middle line of each valve) eighteen +to twenty-two pores, in the half equator (in the cinctural perimeter of +each valve) twenty to twenty-two pores. All pores circular, of the same +size, twice as broad as their bars. + +_Dimensions._--Length of the shell (longitudinal diameter) 0.35, height +(sagittal diameter) 0.34, breadth (lateral diameter) 0.33. + +_Habitat._--North Atlantic, west of Madeira, Station 354, depth 1675 +fathoms. + + +2. _Concharium nucula_, n. sp. (Pl. 123, fig. 3). + +Shell pear-shaped, with costate surface. Oral face somewhat truncated, +broader than the aboral face. Its longitudinal diameter about one-fifth +longer than the two other diameters. Borders of the two valves ovate, +smooth, about as broad as the pores. In the half frontal perimeter of the +shell twenty-two to twenty-four pores, in the half sagittal perimeter +eighteen to twenty, in the half equator sixteen to eighteen. Pores +irregularly roundish, three to four times as broad as the bars. The pores +are so disposed in meridional rows that the crests between the rows +converge towards the two poles of the sagittal axis. + +_Dimensions._--Length of the shell 0.2, height 0.18, breadth 0.16. + +_Habitat._--South Atlantic (west of Tristan da Cunha), Station 332, depth +2200 fathoms. + + +3. _Concharium diatomeum_, n. sp. (Pl. 123, fig. 1). + +Shell nearly spherical, slightly lenticular, somewhat compressed in +dorso-ventral direction; the sagittal diameter therefore somewhat shorter +than the two others. Borders of the two hemispherical valves nearly +circular, quite smooth, about as broad as the length of the largest pores. +In the half frontal perimeter of the shell forty-four to fifty pores; in +the half sagittal perimeter twenty to twenty-four; in the half equator +thirty to thirty-three. Pores different in form and size; the +{1718}marginal pores small, nearly circular; the dorsal and ventral pores +oblongish-hexagonal, twice as long as broad, about four to six times as +long as the bars, regularly arranged in transverse rows. + +_Dimensions._--Length of the shell 0.22, height 0.21, breadth 0.2. + +_Habitat._--Tropical Atlantic, near Sierra Leone, Station 348, depth 2450 +fathoms. + + +4. _Concharium bacillarium_, n. sp. (Pl. 123, fig. 4). + +Shell walnut-shaped, with panelled surface; oral and aboral face of the +same form. Its longitudinal diameter about one-fifth longer than the two +other diameters. Borders of the two cup-shaped valves elliptical, smooth, +with a prominent edge, about as broad as the larger pores. In the half +frontal perimeter of the shell fifty to fifty-five pores, in the half +sagittal perimeter thirty-six to forty, in the half equator also thirty to +forty. Pores hexagonally framed. The pores are tapering in size from the +sagittal plane towards the valve-margins, and so regularly arranged in +meridional rows that the crests between the latter converge towards both +poles of the longitudinal axis. + +_Dimensions._--Length of the shell 0.2, height 0.15, breadth 0.15. + +_Habitat._--Tropical Atlantic, off St. Helena, Station 340, depth 1500 +fathoms. + + +5. _Concharium fragilissimum_, n. sp. + +Shell subspherical, very thin-walled and fragile. Diameter in all +directions nearly the same. Oral and aboral face scarcely different. +Margins of the hemispherical valves extremely thin and hyaline. Pores +irregularly roundish, of very different sizes and unequal forms. The +fragile shell of this species differs in general shape from that of all +other Concharida, and is like that of the Coelodendrida (Pl. 121, fig. 3), +but exhibits neither an apical cupola or galea, nor radial tubes arising +from it. It may be perhaps a young specimen of _Coelodendrum_. + +_Dimensions._--Diameter of the shell 0.22, of the pores 0.002 to 0.02. + +_Habitat._--Mediterranean, Portofino (Haeckel), surface. + + + +Genus 721. _Conchasma_,[337] n. gen. + +_Definition._--#Concharida# with the lateral margins of the valves smooth, +without sagittal keel, but with two caudal horns on the hinge (a dorsal and +a ventral). + +The genus _Conchasma_ is closely allied to the preceding _Concharium_, and +has the same hemispherical valves with smooth margins, without teeth; but +it differs from the latter in the development of two caudal horns or +posterior spines on the aboral hinge, one horn on the aboral end of each +valve. The three species of this genus were all found in great depths of +the Antarctic Ocean, in Diatom ooze, between 1260 and 1975 fathoms, at +Stations 152 to 157. + + +{1719}1. _Conchasma radiolites_, n. sp. (Pl. 123, fig. 5). + +Shell nearly spherical, somewhat compressed on both sides; the dorsal valve +smaller, flatter and shorter than the ventral valve. In the half sagittal +perimeter of the shell twenty to twenty-two pores, in the half frontal +perimeter twelve to fourteen, in the half equator eighteen to twenty. All +pores nearly of the same size, circular, hexagonally framed, scarcely as +broad as the bars. The two horns of the hinge are four-sided pyramidal, of +different sizes; the ventral horn (of the larger valve) two to three times +as long as the dorsal horn (of the smaller valve); the latter twice as long +as a pore. + +_Dimensions._--Length of the shell 0.16, height 0.15, breadth 0.14. + +_Habitat._--Antarctic Ocean, Station 154, depth 1800 fathoms. + + +2. _Conchasma sphaerulites_, n. sp. (Pl. 123, fig. 6). + +Shell nearly spherical, somewhat compressed on both sides, the frontal +diameter therefore somewhat shorter than the two others. Both valves nearly +of the same size, hemispherical, their borders smooth, twice as broad as +the largest pores. In the half sagittal perimeter of the shell twenty-eight +to thirty pores, in the half frontal perimeter twenty to twenty-two, in the +half equator twenty-four to twenty-six. Size of the pores increasing from +the borders towards the top of the valves. One series of very small pores +along the frontal free margin of each valve. Pores roundish-polygonal, +three to four times as broad as the bars. The two horns of the hinge are of +equal size, four-sided pyramidal, and twice as long as the larger pores. + +_Dimensions._--Length of the shell 0.18, height 0.18, breadth 0.16. + +_Habitat._--Antarctic Ocean, Station 152, depth 1260 fathoms. + + +3. _Conchasma hippurites_, n. sp. + +Shell nearly spherical, scarcely compressed. The frontal diameter equal to +the two others. Both valves equal. In the half sagittal perimeter of the +shell thirty-two to thirty-four pores, in the half frontal perimeter +twenty-four to twenty-six, in the half equator twenty-six to twenty-eight. +All pores of nearly equal size, circular, polygonally framed, twice as +broad as the bars. The two horns of the hinge are large, three-sided +pyramidal, the ventral horn twice as long as the dorsal, and four to six +times as long as one pore. + +_Dimensions._--Length of the shell 0.22, height 0.21, breadth 0.2. + +_Habitat._--Antarctic Ocean, Station 157, depth 1950 fathoms. + + + +Subfamily 2. CONCHOPSIDA, Haeckel. + +_Definition._--#Concharida# with the lateral margins of the two valves +dentate, the teeth of both catch one into another. + + + +{1720}Genus 722. _Conchellium_,[338] n. gen. + +_Definition._--#Concharida# with the lateral margins of the valves dentate, +without sagittal keel and without horns on the hinge. + +The genus _Conchellium_ and the four following genera represent together +the subfamily Conchopsida, differing from the Conchasmida in the dentate +lateral margins of the two valves. These are armed with a series of strong, +conical teeth, and catch one into another just as the two valves of many +Lamellibranchiata and Brachiopoda do (Pl. 124, figs. 1-16). _Conchellium_ +is the simplest form among the Conchopsida, since the valves are +hemispherical, and possess neither a sagittal keel nor projecting horns. + + +1. _Conchellium tridacna_, n. sp. (Pl. 123, figs. 7, 7_a_). + +Shell nearly spherical, finely tuberculated, the sagittal diameter somewhat +longer than the two others. Borders of the two hemispherical valves smooth +in 0.2 of the oral, and 0.1 at the aboral part, dentated in the remaining +0.7 part; on one side of each valve fourteen to sixteen very strong and +long teeth, all nearly of the same size, about one-fourth as long as the +shell-radius. In the half frontal perimeter of the shell (on one border of +each valve) twenty-five to thirty pores, in the half sagittal perimeter +thirty-five to forty, in the equator twenty-five to thirty. Pores circular, +hexagonally framed, of equal size (except some smaller rows along the +fissure), twice as broad as the bars. On the conical inside of each +funnel-like pore six small spinules, between every three neighbouring pores +a triangular facette (fig. 7_a_). + +_Dimensions._--Length of the shell 0.34 to 0.38, height 0.38 to 0.42, +breadth 0.32 to 0.36. + +_Habitat._--North Pacific, Stations 250 to 253, depth 2740 to 3125 fathoms. + + +2. _Conchellium hippopus_, n. sp. + +Shell nearly spherical, in the lateral perimeter (along the girdle-fissure) +somewhat constricted. Borders of the two hemispherical valves semicircular, +smooth in 0.3 of the oral, and 0.2 of the aboral part, dentated only in the +remaining 0.5 middle part; on one side of each valve seven to eight very +strong and long teeth, increasing in size towards the mouth, the longest +(foremost) teeth nearly one-third as long as the shell-radius. In the half +frontal perimeter of the shell (along one border of each valve) twenty-four +to twenty-eight pores, in the half sagittal perimeter thirty-two to +thirty-six, in the half equator twelve to fourteen. Pores circular, twice +to three times as broad as the bars, smaller along the fissure. + +_Dimensions._--Length of the shell 0.06, height 0.065, breadth 0.055. + +_Habitat._--Central area of the Tropical Pacific, Station 274, depth 2750 +fathoms. + + + +{1721}Genus 723. _Conchidium_,[339] Haeckel, 1879, Sitzungsb. med.-nat. +Gesellsch. Jena, Dec. 12, p. 6. + +_Definition._--#Concharida# with the lateral margins of the valves dentate, +without sagittal keel and apical horns, but with two caudal horns on the +hinge (a dorsal and a ventral). + +The genus _Conchidium_ is the most common form of all Concharida, and some +of its species occur in great numbers in the tropical zone of the Pacific +and the Atlantic, on the surface as well as at various depths. It differs +from the preceding _Conchellium_, its ancestral form, in the development of +two caudal horns, or two strong pyramidal spines which arise from the +posterior end of the valves; the dorsal horn usually is smaller than the +ventral. + + +1. _Conchidium terebratula_, n. sp. (Pl. 124, figs. 1, 2). + +Shell subspherical, smooth; both valves of nearly equal size and form, +hemispherical. The three dimensive axes of the body are almost equal. +Margins of the valves dentate in nearly the whole periphery; on each side +of one valve eleven or twelve strong conical teeth, all of the same size. +Aboral hinge with two short and stout four-sided pyramidal horns of equal +length. Mouth with two equal short lips. Pores of the shell subregular, +circular, three to four times as broad as the bars, in the dorsal valve +twice as large as in the ventral valve. + +_Dimensions._--Diameter of the shell 0.24 to 0.28. + +_Habitat._--Central Pacific, Stations 270 to 274, surface, and at various +depths. + + +2. _Conchidium thecidium_, n. sp. (Pl. 124, fig. 6). + +Shell subspherical, slightly compressed on both sides. Dorsal valve +somewhat smaller than the ventral, of similar form. Principal axis of the +shell somewhat longer than the sagittal, and this longer than the frontal +axis. Margins of the valves smooth in the oral quarter, strongly dentate in +the remainder; on each side of one valve eight or nine very large +triangular teeth, half as long as the height of the valve. Aboral hinge +with two unequal, stout, four-sided pyramidal horns; the dorsal horn half +as long at the ventral. Mouth with two unequal lips, the upper shorter than +the lower. Pores of the shell subregular, hexagonal, three to four times as +broad as the bars. The figured specimen, well preserved, contained in the +central capsule two nuclei, one in the dorsal, the other in the ventral +half. + +_Dimensions._--Length of the shell 0.28 to 0.33, height 0.27 to 0.3, +breadth 0.22 to 0.24. + +_Habitat._--South Pacific, Station 292, depth 1600 fathoms. + + +{1722}3. _Conchidium rhynchonella_, n. sp. (Pl. 124, fig. 3). + +Shell with three different dimensive axes in the proportion = 6 : 5 : 4. +Ventral valve semi-ovate, larger than the humpbacked dorsal valve. Margins +of the valves dentate almost in the whole periphery; on each side of one +valve twelve or thirteen strong conical teeth. Aboral hinge with two very +unequal horns, the dorsal much smaller than the pyramidal ventral. Under +lip of the mouth emarginate, much larger than the acute upper lip. Pores +subregular, circular, twice as broad as the bars. + +_Dimensions._--Length of the shell 0.3, height 0.25, breadth 0.2. + +_Habitat._--North Pacific, Stations 244 to 253, surface, and at various +depths. + + +4. _Conchidium dimerella_, n. sp. + +Shell laterally compressed, very similar to the preceding, but differing in +the following characters:--Proportion of the three axes = 7 : 5 : 4. +Ventral valve hemispherical, larger than the humpbacked dorsal. Margins of +the valves dentate in the middle half only, whilst the anterior and +posterior quarters are smooth; on each side of one valve six or seven +strong conical teeth. Ventral horn of the aboral hinge very large, +pyramidal, one-third as long as the shell and three times as long as the +dorsal. + +_Dimensions._--Length of the shell 0.35, height 0.25, breadth 0.2. + +_Habitat._--North Pacific, Station 236, surface. + + +5. _Conchidium leptaena_, n. sp. (Pl. 124, figs. 4, 5). + +Shell laterally compressed, with three different dimensive axes of the +proportions = 4 : 3 : 2. Ventral valve larger than the dorsal, both +semi-ovate. Margins of the valves dentate along the lateral sides; on each +side of one valve nine or ten conical teeth, the middle of which are +smaller. Aboral hinge with two unequal short horns; the dorsal rudimentary. +Under lip of the mouth pointed, much larger than the truncate upper lip. +Pores circular, about twice as broad as the bars. + +_Dimensions._--Length of the shell 0.2, height 0.15, breadth 0.1. + +_Habitat._--Central Pacific, Stations 271 and 272, surface, and at various +depths. + + +6. _Conchidium argiope_, n. sp. (Pl. 124, figs. 7-9). + +Shell laterally compressed, with three different dimensive axes of the +proportion = 6 : 5 : 3. Both valves nearly equal. Margins of the shell +dentate along the lateral fissure, on each side of one valve thirteen or +fourteen thin conical teeth. Aboral hinge with two equal, short, pyramidal +horns. Mouth with two equal short lips. Pores subregular, circular, twice +as broad as the bars. + +_Dimensions._--Length of the shell 0.2, height 0.17, breadth 0.1. + +_Habitat._--Tropical Atlantic, Stations 341 to 349, surface, and at various +depths. + + +{1723}7. _Conchidium magasella_, n. sp. + +Shell laterally compressed, with two equal valves, very similar to the +preceding species, but differing in the following characters:--Proportion +of the three axes = 6 : 4 : 3. Margins of the valves with smaller and more +numerous teeth; on each side of one valve sixteen to eighteen short conical +teeth. Pores smaller and more numerous, about as broad as the bars. + +_Dimensions._--Length of the shell 0.24, height 0.16, breadth 0.12. + +_Habitat._--Indian Ocean, Madagascar (Rabbe), surface. + + +8. _Conchidium productum_, n. sp. + +Shell laterally compressed, prolonged, with two equal valves, +similar to the two preceding species, differing in the following +characters:--Proportion of the three axes = 3 : 2 : 1. Margins of the +valves smooth in the anterior and posterior quarter, dentate in the middle +lateral half; on each side of one valve ten to twelve strong conical teeth. +Horns of the aboral hinge prolonged, conical, half as long as the shell, +the ventral somewhat larger than the dorsal. Pores regular, circular, twice +as broad as the bars. + +_Dimensions._--Length of the shell 0.25, height 0.15, breadth 0.08. + +_Habitat._--North Atlantic, Station 354, surface. + + + +Genus 724. _Conchonia_,[340] n. gen. + +_Definition._--#Concharida# with the lateral margins of the valves dentate, +without sagittal keel, but with an apical horn on the poles of the sagittal +axis, and with two caudal horns on the hinge (a dorsal and a ventral). + +The genus _Conchonia_ is closely allied to the preceding _Conchidium_, its +ancestral form, but differs from this and from all other Concharida in the +development of horns on the poles of the sagittal axis. These are probably +of great morphological importance, since they represent the beginnings of +the hollow tubes arising from the poles of the sagittal axis in all +Coelodendrida and Coelographida. In one of the three observed species each +valve possessed an apical or sagittal horn, whilst in the two other species +one valve only was provided with a horn. Since I observed one specimen only +of each species, I cannot say whether this difference is important and of +constant generic value. + + +1. _Conchonia diodon_, n. sp. (Pl. 124, figs. 10-12). + +Shell laterally compressed, with two very unequal valves. Dorsal valve +smaller, hat-shaped, on the apex with a fenestrated protuberance which is +similar to the galea of the Coelodendrida, and bears a short, conical, +backwardly-directed horn. Ventral valve larger, boat-shaped, without apical +{1724}horn. Aboral hinge with two pyramidal, horizontal, caudal horns of +different sizes, the dorsal smaller than the ventral. Lateral margin of +each valve on one side with twelve to fourteen strong conical teeth (fig. +12). Lips of the narrow mouth thickened (fig. 11). + +_Dimensions._--Length of the shell 0.3, height 0.27, breadth 0.21. + +_Habitat._--Tropical Atlantic, Station 342, depth 1445 fathoms. + + +2. _Conchonia triodon_, n. sp. (Pl. 124, figs. 13, 14). + +Shell laterally compressed, with two very unequal valves. Dorsal valve +(fig. 14) larger, hat-shaped, on the apex with a large pyramidal horn which +is half as long as the shell, curved and directed backwards. Ventral valve +(fig. 13) smaller, boat-shaped, without apical horn. Aboral hinge with two +pyramidal caudal horns of different sizes, the dorsal horn twice as long as +the ventral. Lateral margin of each valve on one side with twelve to +fifteen conical teeth. Perhaps the larger horned valve (fig. 14) may be the +ventral, and the opposite smaller hornless (seen from above in fig. 13) the +dorsal valve. + +_Dimensions._--Length of the shell 0.21, height 0.17, breadth 0.12. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +3. _Conchonia tetrodon_, n. sp. + + _Conchura tetrodon_, Haeckel, 1882, Manuscript. + +Shell subspherical, with two nearly equal hemispherical valves, which are +very thin-walled and similar in structure to those of the Coelodendrida, +with very irregular roundish pores of different shapes and sizes (compare +Pl. 121, fig. 3). Lateral margins of the valves with very numerous and +irregular, thin, bristle-shaped teeth, similar to those of some +Coelographida (compare Pl. 127, fig. 8). Aboral hinge with two equal, +conical, caudal horns, which are straight, parallel, and half as long as +the shell. Two similar straight conical horns are opposed on the poles of +the sagittal axis, and arise from the apex of the two valves. This +remarkable species may perhaps better represent a separate genus, +_Conchura_, forming a direct transition to the ancestral form of the +Coelodendrida, _Coelodoras_; it differs from the latter in the absence of a +galea or hollow conical cupola on the apex of each valve, and in the solid, +not hollow structure of the horns. + +_Dimensions._--Diameter of the shell 0.24, length of the two sagittal horns +0.1, of the two caudal horns 0.12. + +_Habitat._--Indian Ocean, Cocos Islands (Rabbe), surface. + + + +Genus 725. _Conchopsis_,[341] Haeckel, 1879, Sitzungsb. med.-nat. +Gesellsch. Jena, Dec. 12, p. 6. + +_Definition._--#Concharida# with dentate lateral margins and a sharp +sagittal keel of the compressed valves, without horns on the hinge. + +{1725}The genus _Conchopsis_ and the following _Conchoceras_ differ from +the other Concharida in the strong lateral compression of the shell, so +that each valve is provided in the sagittal plane with a sharp prominent +keel, comparable to the dorsal and the anal fin of fishes. These compressed +shells are in general twice to three times as large as the more roundish +and keelless shells of the five preceding genera. The sculpture of the +fenestrated valves is extremely elegant. _Conchopsis_ possesses at the +aboral hinge not the two prominent caudal horns, which mark the following +genus _Conchoceras_, but in some species a peculiar ligament connects the +aboral ends of both valves. + + +1. _Conchopsis orbicularis_, n. sp. (Pl. 125, fig. 3). + +Shell subcircular, lenticular, strongly compressed on both sides, nearly as +high as long, its sagittal perimeter nearly circular; frontal and cinctural +perimeter spindle-shaped. Borders of the two boat-shaped valves smooth in +0.4 of the oral part, and in 0.1 of the aboral part of their length, +strongly dentated in the remaining 0.5 middle part; about twenty-five +slender, straight teeth on each side of one valve, size of the teeth +increasing from the aboral towards the oral pole. In the half lateral +perimeter of the shell (along the right and the left borders of each valve) +sixty to sixty-five pores, in the half sagittal perimeter (along the keel +of each valve) eighty to eighty-five pores, in the half equator sixty to +sixty-five pores. + +_Dimensions._--Length of the shell 0.53, height 0.55, breadth about 0.2. + +_Habitat._--South Atlantic, west of Tristan da Cunha, Station 333, depth +2025 fathoms. + + +2. _Conchopsis compressa_, n. sp. (Pl. 125, figs. 7, 8). + +Shell lenticular, strongly compressed on both sides; proportion of its +longitudinal diameter to the sagittal and lateral = 10 : 9 : 3, its +sagittal perimeter elliptical (fig. 7), cinctural and frontal perimeter +spindle-shaped (fig. 8). Borders of the two boat-shaped valves smooth in +0.3 of the oral, and 0.3 in the aboral part, dentated in the remaining 0.4 +middle part; about forty to forty-four very slender teeth of equal size on +one lateral edge of each valve. In the half frontal perimeter of the shell +(along the border of the valve) sixty-four to sixty-eight pores, in the +half sagittal perimeter (along one valve-keel) seventy to eighty pores, in +the half equator forty-four to forty-eight pores. Ventral and dorsal pores +linear, three to four times as long as the circular, lateral pores. + +_Dimensions._--Length of the shell 0.6 to 0.8, height 0.55 to 0.72, breadth +0.2 to 0.3. + +_Habitat._--North Pacific, between 30d and 40d north latitude (between +Japan and San Francisco), in depths from 2000 to 3000 fathoms frequent, +Stations 241 to 252. + + +3. _Conchopsis carinata_, n. sp. (Pl. 123, fig. 8). + +Shell subcircular, lenticular, in the central half slightly compressed, +nearly spherical, in the peripheral half strongly compressed, with a broad, +hyaline, smooth keel on the sagittal plane. Borders of the two valves +smooth in the 0.2 of the oral, and 0.1 of the aboral part, strongly +{1726}dentated in the remaining 0.7 middle part; about fifty slender teeth +of equal size on one lateral edge of each valve. In the half lateral +perimeter of the shell about forty-five to fifty pores, in the half +sagittal perimeter sixty-five to seventy, in the half equator thirty-two to +forty pores. The pores are arranged in parallel curved rows, which are +separated by high denticulate crests. Aboral hinge with a strong ligament. + +_Dimensions._--Length of the shell 0.6 to 0.7, height 0.55 to 0.65, breadth +0.35 to 0.45. + +_Habitat._--South Atlantic (east of Patagonia), Station 318, depth 2040 +fathoms. + + +4. _Conchopsis lenticula_, n. sp. (Pl. 123, fig. 9). + +Shell subcircular, lenticular, strongly compressed on both sides, with a +sharp and broad hyaline keel in the sagittal perimeter. Borders of the two +valves smooth in 0.3 of the oral, and 0.2 of the aboral part, strongly +dentated in the remaining 0.5 middle part; about thirty strong, conical +teeth on the lateral edge of each valve. In the half lateral perimeter of +the shell fifty to fifty-five pores, in the half sagittal seventy to +seventy-five, in the half frontal forty to forty-five pores. The large +central capsule of this species fills up the posterior half of the +shell-cavity, the dark green phaeodium the anterior half; the latter +contains numerous peculiar, longish, nucleated cells (fig. 9_a_), parasites +or symbiontes (?). Aboral hinge of the shell with a strong ligament. + +_Dimensions._--Length of the shell 0.7, height 0.6, breadth 0.3. + +_Habitat._--Central Pacific, Stations 271 to 274, depth 2350 to 2750 +fathoms. + + +5. _Conchopsis pilidium_, n. sp. (Pl. 125, fig. 9). + +Shell ovate, lenticular, compressed on both sides, with a broad, wing-like +sagittal keel. Proportion of its longitudinal diameter to the sagittal and +lateral = 6 : 5 : 3. Sagittal perimeter elliptical. Borders of the two +hat-like valves smooth in 0.15 of the oral, and 0.2 of the aboral part, +strongly dentated in the remaining 0.65 middle part; about twenty-five to +thirty teeth of nearly equal size on one side of each valve. In the half +lateral perimeter of the shell (along one border of each valve) forty-five +to fifty pores, in the half sagittal perimeter (on the keel of one valve) +seventy to seventy-five pores, in the half equator thirty-six to forty +pores. Each pore is surrounded by a hexagonal frame. The opening of each +valve in this species is bordered and partly closed by a broad, horizontal +diaphragm or velum, like the deck of a boat; it is broadest on the oral +side. + +_Dimensions._--Length of the shell 0.78 to 0.8, height 0.66 to 0.7, breadth +0.3 to 0.4. + +_Habitat._--South Atlantic, between Buenos Ayres and Tristan da Cunha, +Stations 324 to 334, at depths between 1715 and 2900 fathoms. + + +6. _Conchopsis aspidium_, n. sp. (Pl. 125, figs. 1, 2). + +Shell scutiform, strongly compressed on both sides, in the centre only +lenticular, in the periphery wing-like, keeled. Proportion of the +longitudinal diameter to the sagittal and frontal = 6 : 5 : 2. Sagittal +circumference in the oral half semicircular, in the aboral half pentagonal, +two {1727}acute corners jutting out near the aboral hinge, one corner in +the keel of the dorsal, the outer in the keel of the ventral valve. Borders +of the two boat-shaped valves smooth in 0.3 of the oral part, and in 0.1 of +the aboral part, strongly dentated in the remaining 0.6 middle part; about +thirty-five teeth in one side of each valve, larger on both ends than in +the middle. In the half frontal perimeter of the shell sixty to sixty-five +pores, in the half sagittal perimeter eighty to eighty-five, in the half +equator of the shell forty to fifty pores. + +_Dimensions._--Length of the shell 0.55 to 0.65, height 0.5 to 0.55, +breadth 0.2 to 0.22. + +_Habitat._--North Pacific, Stations 243 and 244, depth 2800 to 2900 +fathoms. + + +7. _Conchopsis navicula_, n. sp. (Pl. 125, figs. 4-6). + +Shell pear-shaped, compressed on both sides, in the sagittal periphery +keeled. Proportion of the longitudinal diameter to the sagittal and lateral += 4 : 3 : 2. Its sagittal perimeter nearly ovate. Borders of the two +boat-shaped valves smooth in 0.3 of the oral, and 0.15 of the aboral part, +strongly dentated in the remaining 0.55 middle part; teeth conical, of +nearly equal size. In the half frontal perimeter of the shell (along one +border of each valve) forty to forty-five pores, in the half sagittal +fifty-four to fifty-six pores, in the half equator thirty-two to thirty-six +pores. Each pore is surrounded by a hexagonal frame, and pierces the shell +in an oblique direction, dilated in the middle part (figs. 5, 6). Shell +very thick-walled, several longitudinal crests on both sides of the keel of +each valve. Hinge very strong, usually with a broad ligament between the +two unequal aboral lips of the hinge. + +_Dimensions._--Length of the shell 0.8, height 0.6, breadth 0.4. + +_Habitat._--South Pacific, Station 293, depth 2025 fathoms. + + + +Genus 726. _Conchoceras_,[342] Haeckel, 1879, Sitzungsb. med.-nat. +Gesellsch. Jena, Dec. 12, p. 6. + +_Definition._--#Concharida# with dentate lateral margins and a sharp +sagittal keel of the compressed valves, and with two caudal horns on the +hinge (a dorsal and a ventral). + +The genus _Conchoceras_ has the same lenticular keeled and laterally +compressed shell as the preceding ancestral genus _Conchopsis_, but is +distinguished from it by the development of two large caudal horns on the +aboral hinge. It bears therefore the same relation to the latter as +_Conchidium_ does to _Conchellium_. + + +1. _Conchoceras caudatum_, n. sp. (Pl. 124, fig. 15). + +Shell lenticular, slightly compressed; proportion of the longitudinal +diameter to the sagittal and lateral = 6 : 5 : 4; sagittal and cinctural +perimeter ovate, frontal perimeter elliptical. Free {1728}margins of the +two boat-shaped valves dentate nearly in the whole perimeter; in one +lateral border of each valve eleven or twelve very large conical teeth, the +largest of which are nearly half as high as the valve. On the aboral hinge +of the shell two divergent, very large horns, four-sided pyramidal, acute, +straight, at the base perforated by a few large pores. The dorsal horn (of +the smaller valve) is somewhat shorter than the ventral horn (of the larger +valve). The apical distance of both horns is somewhat greater than their +length, and about half the length of the shell. In the half frontal +perimeter (along one border of each valve) thirty-two to thirty-four pores, +in the half sagittal perimeter thirty-four to thirty-eight, in the half +equator thirty to thirty-three. The pores are smaller near the +girdle-fissure, irregularly quadrangular, and arranged in longitudinal +rows, which are separated by meridional crests, and converge towards both +poles of the main axis. + +_Dimensions._--Length of the shell (without the horns) 0.24 to 0.26, height +0.20 to 0.22, breadth 0.16 to 0.18; length of the horns 0.1 to 0.13. + +_Habitat._--Eastern part of the Tropical Atlantic, near the Equator, +Station 348, depth 2450 fathoms. + + +2. _Conchoceras cornutum_, n. sp. (Pl. 124, fig. 16). + +Shell lenticular, strongly compressed on both sides; proportion of the +longitudinal axis to the sagittal and lateral = 4 : 3 : 2. Sagittal +perimeter ovate, frontal perimeter elliptical, cinctural perimeter +spindle-shaped. Free margins of the two keeled valves in the oral third +smooth, in the remaining part strongly dentate; ten or eleven large teeth +on one lateral border of each valve, the largest about half as high as the +valve. On the aboral hinge of the shell two fenestrated apophyses which +bear two stout, strongly curved horns, like pincers; the dorsal horn (of +the smaller upper valve) is shorter and less curved than the ventral horn +(of the larger lower valve). The lips of the mouth (at left on fig. 16) are +also unequal, the upper lip emarginate. In the half frontal perimeter of +the valve twenty-two to twenty-four pores, in the half sagittal perimeter +twenty-eight to thirty, in the half equator twenty to twenty-two. The pores +are separated by high parallel crests and arranged in longitudinal rows, +which converge towards the aboral hinge. + +_Dimensions._--Length of the shell (without the horns) 0.36 to 0.4, height +0.27 to 0.3, breadth 0.2 to 0.22; length of the horns 0.16 to 0.22. + +_Habitat._--Tropical Atlantic, Station 338, depth 1990 fathoms. + + + +Family LXXXIV. #COELODENDRIDA#, Haeckel (Pl. 121). + + _Coelodendrida_, Haeckel, 1862, Monogr. d. Radiol., p. 360. + +_Definition._--PHAEODARIA with a bivalved lattice-shell, composed of two +hemispherical valves, a dorsal and a ventral. A conical cupola or a +pyramidal galea arises from the apical pole of both valves, therefore at +the opposite poles of the sagittal axis. Rhinocanna and frenula wanting. +Three or more hollow radial tubes arise from each valve and are +symmetrically disposed. Sometimes their branches form an outer +{1729}bivalved mantle. The central capsule is so enclosed between the two +inner valves, that its three openings lie in the open frontal fissure +between them. + +The family #Coelodendrida# differs from the preceding Concharida (its +probable ancestral group) in the development of a conical galea or +pyramidal cupola on the apical pole of each valve, and of three or more +hollow radial tubes arising from each galea. They do not possess, however, +the peculiar sagittal nasal tube or rhinocanna, which is constantly +developed from the base of each cupola (and connected with its apex by a +frenulum) in the following family, the Coelographida. These latter differ +also from the former in the constant possession of prominent verticillate +styles. + +The family Coelodendrida was founded in 1862 in my Monograph (p. 360) and +represented hitherto only by two species of the genus _Coelodendrum_, there +described (p. 361, Taf. xiii. figs. 1-3, and Taf. xxxii. fig. 1). This +first description, however, contained some errors, which were afterwards +(in 1879) corrected by Richard Hertwig; this author also gave the first +accurate description of the central capsule and its three openings. In the +rich collection of the Challenger, the Coelodendrida are represented by +four genera, but only seventeen species, some of which, however, are +cosmopolitan and very common, particularly _Coelodendrum_. + +The two valves of the lattice-shell, dorsal and ventral, are either +hemispherical, or somewhat more flatly vaulted or cap-shaped. They are +never connected in the equatorial zone of the body, as I supposed in my +Monograph (1862, _loc. cit._); but they are separated by the +girdle-fissure, a free circular equatorial interval, in which lie the three +openings of the enclosed central capsule. Though the two valves, therefore, +have no direct connection, they are, however, always opposed so accurately, +that their equal free circular edges correspond exactly one to the other, +so that the apex of each valve lies in one pole of the sagittal axis. From +this apex there arises on each valve an irregular conical or three-sided +pyramidal cupola, the galea (Pl. 121, figs. 3, 4, 8). The Coelodendrida +differ in the possession of this galea from the Concharida, and agree with +the Coelographida; but they never exhibit the peculiar rhinocanna or nasal +tube, which arises from each galea in the latter family. + +The siliceous lattice-plate of the two valves, and of the galea arising +from them, is very thin and fragile, and its irregular roundish pores are +extremely variable in size, number, and disposition. Sometimes the pores +are so small and so scarce, that the plate appears nearly solid. At other +times the siliceous plate seems to be really solid, and covered by a +network of thin crests, the small dimples between which give to it the +appearance of being fenestrated. Often the pores or the dimples are wanting +in the central part of each valve, while they are very numerous and dense +in the peripheral part. The same may be said of the lattice-plate of the +galea, which is sometimes nearly solid, at other times richly fenestrated. +The Coelodendrida agree in this structure with the following {1730}family, +the Coelographida, and differ from the preceding family, the Concharida, in +which the siliceous wall of the two valves is much thicker, and perforated +by regular circular or roundish pores. + +The galea or conical cupola in the apex of the two valves ("der +kegelfoermige Aufsatz" of the German authors) has in all Coelodendrida a +triangular base and an irregularly conical or nearly three-sided pyramidal +form. Its cavity is about one-third or one-fourth as large in diameter as +the cavity of the hemispherical valve upon which it rests. The galea is +relatively smaller and more irregularly formed than in the Coelographida, +and differs essentially from that of the latter in the constant absence of +a rhinocanna; there are also wanting, therefore, the characteristic +frenula, which connect the nasal tube with the apex of the galea. The +cavity of the galea probably always communicates with that of the valves by +pores in the separating siliceous plate, and is besides pierced by +irregular pores in its outer wall, very variable in form, size, and number, +but it does not communicate with the cavity of the hollow radial tubes, +from which it is separated by a thin, solid, siliceous plate. + +The hollow radial tubes which arise from the galea in the Coelodendrida do +not seem to possess that constant regularity in number, origin, and +disposition, which is found in the following family, and there serves for +distinction of genera. In my first description of the Coelodendrida (1862, +_loc. cit._, p. 362), I pointed out this irregularity, and mentioned that +the number of radial tubes arising from each galea varies from three to +eight; the total number therefore amounts to from six to sixteen, the same +minimum and maximum numbers which we shall encounter also in the radial +styles of the following family. But whilst it is easy to determine the +position and relation of these hollow tubes in the Coelographida, owing to +the constant sagittal position of their rhinocanna, this task is very +difficult in the Coelodendrida, where the rhinocanna is wanting. In the +most frequent cases there arise from each galea three or four tubes, more +rarely five or six, and very rarely seven or eight. The simplest and +probably the original case is the development of three tubes, two of which +are paired (divergent on the right and left), while the third is odd, lying +in the sagittal plane. Perhaps these three primary tubes may be compared to +the three cortinar feet of the NASSELLARIA, so that we may regard the two +paired anterior as pectoral, and the odd posterior as a caudal tube. +Usually the two paired or pectoral tubes arise from two corners of the +triangular base of the galea, whilst the third odd or caudal tube does not +arise from the third corner of the base, but more or less above it, and +often even from the highest point or the apex of the galea. In the majority +of species observed, this odd sagittal tube is forked even at its origin, +so that two divergent tubes (an anterior and a posterior) arise from the +apex of the galea (Pl. 121, figs. 3, 8). More rarely the two paired or +pectoral tubes are also forked at the base, so that three pairs of tubes +arise from each galea, and the total number of tubes amounts to twelve. +Very rarely {1731}four separate tubes or four pairs of tubes arise from +each galea, viz., two from the two anterior corners of the basal triangle, +one from the posterior corner, and one from the apex of the galea. It is +possible that this difference in the origin, furcation, and number of the +hollow radial tubes may be employed for the distinction of genera of +Coelodendrida, in the same manner as it is employed in the next following +family, the Coelographida. But I have not been able, in spite of numerous +and accurate examinations, to demonstrate in the former the same regularity +in number and arrangement of the tubes as in the latter. It seems that +these relations here are very variable, even in one and the same Species, +and not yet fixed. + +It is, however, probable, on the other hand, that the primary tubes (all or +partly) are identical to the Coelodendrida and Coelographida. This is most +probably the case with the posterior odd or caudal tube, which seems to be +never wanting, and in both families is developed in the form of a +dichotomous brush (never in the form of a verticillate style). Possibly +also the two paired pectoral tubes are homologous in both families. + +The hollow tubes are perfectly simple and unbranched only in one genus, +_Coelodoras_, which is probably the common ancestral form of both families, +and which may have been derived from _Concharium_ by development of a galea +and tubes on the sagittal apex of the valves. All the other Coelodendrida +have branched spines, and the ramification is constantly dichotomous, or +repeatedly forked. There never occur in this family those characteristic +"styles," or verticillate prolonged tubes, which we find in all +Coelographida. Usually the cylindrical tubes are slightly curved and forked +even near their base. The furcation is repeated a variable number of times +in the different species. In the largest species each tube becomes a brush +with more than one hundred terminal bristles. + +We divide the Coelodendrida into two subfamilies, according to the +different development of the distal branches of the hollow tubes. In the +Coelodorida all the branches of the tubes remain free and are never +connected by anastomoses, so that the surface of the bivalved skeleton is +protected by the free radial distal branches of the tubes. In the larger +species of _Coelodendrum_ (_e.g._, _Coelodendrum furcatissimum_, Pl. 121, +fig. 1), the numerous branches of the dichotomous tubes form a dense +thicket, similar to that in the Coelotholida. + +In the second subfamily, Coelodrymida, the distal branches of the tubes are +connected by numerous anastomoses, and compose either a simple +lattice-plate on the surface of the skeleton (_Coelodrymus_), or a thicker +envelope of spongy framework (_Coelodasea_). The lattice-mantle so produced +is always bivalved, and its two outer hemispherical valves (dorsal and +ventral) correspond exactly to the two inner valves, from which arise the +hollow tubes. The free margins of the two external mantle-valves come +externally into contact in the equatorial plane of the body, in which the +girdle-fissure lies internally between the two central shell-valves. The +free edges {1732}of the two external mantle-valves, opposed to one another +in the circle of the equator, seem usually to catch one into another in the +same way as the corresponding mantle-valves of the Coeloplegmida are +loosely connected (Pl. 128, figs. 1, 7). A true concrescence between the +two valves seems never to take place. + +The two subfamilies of Coelodendrida therefore exactly correspond to the +two subfamilies of the following family, the Coelographida. The Coelodorida +and Coelotholida form in a similar way a thicket, by dichotomous +ramification of the hollow tubes, all the branches of which remain free. +The Coelodrymida and Coeloplegmida, on the other hand, form an outer +lattice-mantle by anastomosing branches. The latter two subfamilies, of +course, have been derived correspondingly from the two former, and the +common ancestral form of all four is probably _Coelodoras_, derived from +the Concharida. + +Though the two corresponding subfamilies in both groups are very similar, +they are, however, separated by important hereditary characters. All +Coelodendrida (the Coelodorida without a mantle as well as the Coelodrymida +with a mantle) possess no rhinocanna and no frenula on the galea, and they +never develop prominent verticillate styles; the surface of their calymma +is probably always spherical or subspherical. All Coelographida, however +(the Coelotholida without a mantle as well as the Coeloplegmida with a +mantle), possess a rhinocanna and frenula on the galea, and always develop +prominent verticillate styles; the surface of their calymma is probably +always symmetrically polyhedral. + +The superficial armature of the skeleton in the Coelodendrida is rather +simple, and by no means so manifold and differentiated as in the more +highly developed Coelographida. The thin terminal branches of the hollow +tubes are in the Coelodorida closed at the distal end, and armed with a +variable number of short teeth (Pl. 121, fig. 2), or with a spinulate +terminal knob, or a corona of recurved hooks (_ibid._, figs. 5-7). In the +Coelodrymida, however, where the distal ends of the branches by +anastomosing form the lattice-mantle, the spherical surface of this latter +is armed with numerous thin spathillae or radial bristles (often zig-zag or +spinulate), and each bristle usually bears at the distal end a small anchor +with two, three, or four recurved teeth; the outer convex edge of these +teeth is usually smooth, the inner concave edge denticulate. All these +ramules and branches of the tubes (also the thinnest terminal threads) are +hollow, and filled up by jelly. + +The _central capsule_ of the Coelodendrida does not lie outside the two +central valves (as I supposed in my first description, in 1862, being +deceived by the dark enveloping phaeodium, Monogr. d. Radiol., Taf. xxxii. +fig. 1), but it is enclosed between the two valves, as in the preceding and +the following family. The first accurate description of it was given by +Richard Hertwig in 1879 (_loc. cit._, p. 95, Taf. x. fig. 3). Its constant +position between the two lattice-valves (dorsal and ventral) is such, that +its three openings lie in the frontal plane, in the open fissure between +the valves. The astropyle or the main-opening, with the radiate operculum +and the tubular proboscis arising from it, lies on the anterior (or oral) +{1733}pole of the main axis, whilst the two lateral accessory openings, or +parapylae, lie on both sides of the posterior (or aboral) pole, to the +right and left. The position of the capsule is therefore the same as in the +preceding Concharida (Pls. 123-125), and the following Coelographida (Pls. +126-128). The large nucleus, enclosed in the central capsule, is usually +half as broad, and contains numerous nucleoli. + +The calymma, or the extracapsular jelly-veil, is in the Coelodendrida +usually spherical, very voluminous, and includes the entire skeleton, the +thicket of the Coelodorida as well as the lattice-mantle of the +Coelodrymida. Only the outermost terminal branches of the tubes in the +former, and the radial bristles and spathillae on the surface of the +latter, remain free and project beyond the surface of the calymma. The +phaeodium is usually very large, three to four times as broad as the +central capsule, and envelops it often completely. Usually it envelops only +the anterior half of it, and the proboscis (Pl. 121, figs. 1, 9). Often +numerous green, brown, or blackish phaeodellae are scattered through the +whole calymma, and sometimes accumulate in a superficial layer on its +surface. The galea of both valves is usually also filled up by the +phaeodium. + +_Synopsis of the Genera of Coelodendrida._ + + ------------------------------------------------------------------------- + I. Subfamily Coelodorida. + Hollow tubes, arising from the galea of both valves, simple or + dichotomously branched; the branches always free, not anastomosing. + No outer lattice-mantle. + ------------------------------------------------------------------------- + Tubes simple, not branched, 727. _Coelodoras_. + + Tubes forked or dichotomously branched, 728. _Coelodendrum_. + ------------------------------------------------------------------------- + II. Subfamily Coelodrymida. + Hollow tubes, arising from the galea of both valves, dichotomously + branched; the branches anastomose and form an outer bivalved + lattice-mantle. + ------------------------------------------------------------------------- + Lattice-mantle simple; its meshes lying + in a spherical surface, 729. _Coelodrymus_. + + Lattice-mantle spongy; its meshes lying + in different planes, 730. _Coelodasea_. + + + +Subfamily I. COELODORIDA, Haeckel. + +_Definition._--#Coelodendrida# without an external bivalved lattice-mantle, +with simple or branched hollow tubes, the terminal branches of which are +free, not anastomosing. + + + +Genus 727. _Coelodoras_,[343] n. gen. + +_Definition._--#Coelodendrida# without external lattice-mantle, with +simple, not branched, radial tubes, which arise separately from the galea. + +{1734}The genus _Coelodoras_ is the simplest form of the Coelodendrida, and +may be regarded as the common ancestral form of this and of the following +family. It differs from all other members of these two families in the +simple shape of the hollow radial tubes which arise from the galea, and are +neither branched nor forked; the galea is very small, a flat triangular +cap. _Coelodoras_ may be derived immediately from _Concharium_ or +_Conchonia_ (p. 1723), by development of the galea and the radial tubes. + + +1. _Coelodoras hexagraphis_, n. sp. + +Three straight, cylindrical, equidistant hollow tubes arise divergent from +the three corners of each galea, and are about as long as the diameter of +the valves, at the distal end armed with a spinulate knob. The odd sagittal +(or caudal tube) is directed backwards, the two paired (or pectoral) tubes, +forwards. + +_Dimensions._--Diameter of the valves 0.16, length of the tubes 0.2. + +_Habitat._--Central Pacific, Station 266, depth 2750 fathoms. + + +2. _Coelodoras octographis_, n. sp. + +Four hollow cylindrical tubes, slightly curved, arise divergent from each +galea, and are about one and a half times as long as the diameter of the +valves, at the distal end knob-shaped, and armed with four crossed, +recurved teeth. Two anterior (or pectoral) tubes arise from the two frontal +corners of the galea basis, and diverge forwards to right and left. Two +posterior tubes (a sagittal and a caudal) arise from the posterior corner +of each galea, and diverge in the sagittal plane backwards. + +_Dimensions._--Diameter of the valves 0.2, length of the tubes 0.3. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + + +Genus 728. _Coelodendrum_,[344] Haeckel, 1860, Monatsber. d. k. preuss. +Akad. d. Wiss. Berlin, p. 801. + +_Definition._--#Coelodendrida# without external lattice-mantle, with +branched radial tubes, the hollow branches of which are free and never +connected by anastomoses. + +The genus _Coelodendrum_ is the first described form not only of the family +Coelodendrida, but of all #Phaeoconchia# or bivalved PHAEODARIA; it is also +the most common form of this group, and represented by ten different +species, some of which are cosmopolitan, very common, and widely +distributed. In my first description of _Coelodendrum_ I confounded it +erroneously with some forms of _Coelodasea_ and _Coelographis_, the +separated fragments of which I had found entangled between the branches of +the former. The first figures of _Coelodendrum_ are given in my Monograph, +in 1862, {1735}Taf. xiii. figs. 1-3 (not 4) and Taf. xxxii. fig. 1 (not 2 +and 3). _Coelodendrum_ has been derived from _Coelodoras_ by furcation and +repeated dichotomous ramification of the hollow radial tubes which arise +from the galea. + + + +Subgenus 1. _Coelodendridium_, Haeckel. + +_Definition._--Ramification of the hollow tubes regularly dichotomous, each +branch being forked again; therefore the two terminal ramules of the last +branches equal. + + +1. _Coelodendrum ramosissimum_, Haeckel. + + _Coelodendrum ramosissimum_, Haeckel, 1862, Monogr. d. Radiol., p. 363, + Taf. xiii. figs. 1-3. + + _Coelodendrum ramosissimum_, R. Hertwig, 1879, Organism. d. Radiol., p. + 93, Taf. x. figs. 3, 12. + +Terminal branches regularly forked, with two equal, smooth, nearly straight +or slightly curved fork-branches, diverging at right angles; their +end-knobs with four crossed (or sometimes five or six) short recurved +teeth. + +_Dimensions._--Diameter of the spherical skeleton 1.2 to 1.8, of the two +central valves 0.2 to 0.25. + +_Habitat._--Cosmopolitan; Mediterranean, Atlantic, Indian, Pacific; many +Stations, surface and at various depths. + + +2. _Coelodendrum spinosissimum_, n. sp. (Pl. 121, fig. 7). + +Terminal branches regularly forked, with two equal, smooth, straight, +fork-branches, diverging at right angles, their end-knobs echinoidal, +subspherical or club-shaped, with numerous short radial thorns. + +_Dimensions._--Diameter of the skeleton 2 to 2.2, of the two central valves +0.25 to 0.03. + +_Habitat._--Tropical Atlantic, Stations 346 to 349, surface. + + +3. _Coelodendrum furcatissimum_, n. sp. (Pl. 121, fig. 1-4). + +Terminal branches regularly forked, with two equal, smooth, straight, or +slightly curved fork-branches, diverging at acute angles; their end-knobs +very small, with three short, diverging, conical teeth. + +_Dimensions._--Diameter of the skeleton 2 to 2.5, of the two central valves +0.3 to 0.4. + +_Habitat._--Cosmopolitan; Atlantic, Indian, Pacific; many Stations, +surface, and at various depths. + + +4. _Coelodendrum bifurcum_, n. sp. + +Terminal branches regularly forked, with two equal, smooth, more or less +curved fork-branches, diverging at acute angles; their end-knobs thin, with +two slender, parallel, bristle-shaped teeth. + +_Dimensions._--Diameter of the skeleton 0.6 to 0.8, of the two central +valves 0.1 to 0.15. + +_Habitat._--North Pacific, Stations 252 to 256, surface. + + +{1736}5. _Coelodendrum gracillimum_, Haeckel. + + _Coelodendrum gracillimum_, Haeckel, 1862, Monogr. d. Radiol., p. 364, + pl. xxxii. fig. 1. + +Terminal branches regularly forked, with two equal, spinulate, curved +fork-branches, diverging at obtuse angles and covered with numerous small +thorns; their end-knobs cap-shaped, with a corona of six to eight small +recurved teeth. In one specimen of this species (in 1859) I found entangled +the fragments of _Coelographis gracillima_, figured in Taf. xxxii. figs. 2, +3, _loc. cit._ I supposed at that time, erroneously, that the latter +belonged to full-grown specimens of the former. + +_Dimensions._--Diameter of the skeleton 1 to 1.2, of the valves 0.15 to +0.2. + +_Habitat._--Mediterranean (Messina), surface. + + +6. _Coelodendrum lappaceum_, n. sp. + +Terminal branches regularly forked, with two equal, spinulate, straight or +slightly curved fork-branches, diverging at acute angles and covered with +small recurved hooks; their end-knobs large, conical, with a prominent apex +and a basal corona of six to eight recurved teeth. + +_Dimensions._--Diameter of the skeleton 1.5 to 1.8, of the valves 0.22. + +_Habitat._--South Pacific, Stations 285 to 295, depth 1500 to 2600 fathoms. + + + +Subgenus 2. _Coelodendronium_, Haeckel. + +_Definition._--Ramification of the hollow tubes more or less irregular, +mainly in the periphery; the terminal ramules of the last branches unequal. + + +7. _Coelodendrum cervicorne_, n. sp. (Pl. 121, fig. 8). + +Terminal branches irregularly ramified, with unequal, smooth, curved +ramules, diverging at obtuse angles, their end-knobs echinoidal, small, +with short, diverging, conical thorns. + +_Dimensions._--Diameter of the skeleton 1 to 1.2, of the valves 0.2. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + +8. _Coelodendrum digitatum_, n. sp. + +Terminal branches irregularly ramified, with unequal, spinulate, straight +ramules, diverging at acute angles; the two last fork-branches digitate, +each with five diverging finger-shaped ramules, lying in a meridian plane; +their end-knobs conical, pointed, with a corona of recurved hooks. + +_Dimensions._--Diameter of the skeleton 1.6, of the valves 0.24. + +_Habitat._--Indian Ocean, Madagascar (Rabbe), surface. + + +{1737}9. _Coelodendrum flabellatum_, n. sp. (Pl. 121, fig. 6). + +Terminal branches flabellate, irregularly ramified, each of the last two +fork-branches being divided into four or five diverging straight branches +of different lengths; usually the last eight or ten ramules lie in a +meridional plane; their end-knobs cap-shaped, with a corona of recurved +teeth. + +_Dimensions._--Diameter of the skeleton 2.0 to 2.5, of the valves 0.25 to +0.3. + +_Habitat._--North Pacific, Station 235 to 240, surface. + + +10. _Coelodendrum serratum_, n. sp. (Pl. 121, fig. 5). + +Terminal branches flabellate, irregularly ramified like the preceding +species; it differs from this in the strong compression of the broad, +saw-shaped, terminal branches; the two opposite edges (placed in the +meridional plane of the flabellum) are finely serrated; their end-knobs +with a corona of diverging teeth. + +_Dimensions._--Diameter of the skeleton 3.0 to 3.2, of the valves 0.3 to +0.36. + +_Habitat._--Central Pacific, Stations 270 to 274, depth 2350 to 2925 +fathoms. + + + +Subfamily 2. COELODRYMIDA, Haeckel. + +_Definition._--#Coelodendrida# with an external bivalved lattice-mantle, +produced by the anastomosing branches of the hollow radial tubes. + + + +Genus 729. _Coelodrymus_,[345] Haeckel, 1879, Sitzungsb. med.-nat. +Gesellsch. Jena, Dec. 12, p. 6. + +_Definition._--#Coelodendrida# with an external bivalved lattice-mantle, +produced by the anastomosing terminal branches of the hollow tubes, which +are connected in a spherical face. + +The genus _Coelodrymus_, and the following closely allied genus +_Coelodasea_, represent together the small subfamily Coelodrymida, +differing from the Coelodorida in the possession of an outer bivalved +lattice-mantle. They exhibit therefore the same relation to the latter, +that in the following family the Coeloplegmida bear to the Coelotholida. +The bivalved spherical mantle is composed of a simple lattice-plate in +_Coelodrymus_, of a spongy framework in _Coelodasea_; the anastomosing +branches of the hollow radial tubes become connected in the former in a +spherical face, in the latter in the form of a spongy framework. + + +{1738}1. _Coelodrymus ancoratus_, n. sp. (Pl. 121, figs. 9, 10). + +Network of the mantle loose, with large, irregular, polygonal meshes; the +terminal branches of the forked trees, which communicate at the spherical +surface of the calymma, and compose the mantle, are smooth. Spherical +surface covered with very numerous and thin zigzag radial filaments, which +are about as long as the galea, and bear at the distal end an anchor with +two recurved teeth, denticulate at the concave proximal edge (fig. 10). + +_Dimensions._--Diameter of the spherical lattice-mantle 2 to 2.5, of the +valves 0.3 to 0.4. + +_Habitat._--South-Eastern Pacific (off Juan Fernandez), Station 300, depth +1375 fathoms. + + +2. _Coelodrymus lappulatus_, n. sp. + +Network of the mantle rather dense, with numerous and small irregular +polygonal meshes; the terminal branches of the forked trees, which compose +the mantle, are spinulate. Spherical surface densely studded with very +numerous spinulate, radial filaments, which are about half as long as the +galea, and bear at the distal end an anchor with four crossed recurved +teeth, denticulate at the concave proximal edge. + +_Dimensions._--Diameter of the spherical lattice-mantle 2.5 to 3, of the +valves 0.4 to 0.5. + +_Habitat._--South-Western Pacific (east of New Zealand), Station 169, depth +700 fathoms. + + +3. _Coelodrymus echinatus_, n. sp. + +Network of the mantle very dense, with very numerous and small irregular +roundish meshes; the terminal branches of the forked trees, which compose +the mantle, are spiny. Spherical surface studded with very numerous, thin, +radial bristles, which bear no anchor at the distal end. + +_Dimensions._--Diameter of the spherical lattice-mantle 1.8, of the valves +0.22. + +_Habitat._--South Pacific, Station 289, depth 2550 fathoms. + + + +Genus 730. _Coelodasea_,[346] n. gen. + +_Definition._--#Coelodendrida# with an external spongy lattice-mantle, +produced by the anastomosing branches of the hollow tubes, which are +connected in different heights. + +The genus _Coelodasea_ differs from the preceding _Coelodrymus_ in the +spongy structure of the outer bivalved mantle. The hollow branches of the +radial tubes of _Coelodendrum_, which anastomose in _Coelodrymus_ only on +the spherical surface of the calymma, and form a simple lattice-sphere, +become connected in _Coelodasea_ in different planes (laterally and +terminally), and therefore form an irregular spongy framework. The latter +exhibits therefore to the former a relation similar to that which +_Spongoplegma_ bears to _Carposphaera_ among the #Sphaeroidea#. + + +{1739}1. _Coelodasea ramosissima_, Haeckel. + + _Coelodendrum ramosissimum_ (_partim_), Haeckel, 1862, Monogr. d. + Radiol., p. 363, Taf. xiii. fig. 4. + +Spongy framework of the spherical bivalved mantle very dense and thick, +produced by very numerous, irregular anastomoses of the lateral and +terminal branches, which arise from the hollow tubes. The last and thinnest +terminal branches are forked, as seen in the radial section of fig. 4 +(_loc. cit._), their ends are closed and armed with some very small +denticles (not open, as figured in fig. 4). In my Monograph I had +confounded this species with _Coelodendrum ramosissimum_, which however, +may possibly be its ancestral form. + +_Dimensions._--Diameter of the spongy spherical mantle 2 to 2.5, of the +central valves 0.15. + +_Habitat._--Mediterranean (Messina), surface. + + +2. _Coelodasea spongiosa_, n. sp. + +Spongy framework of the bivalved mantle rather loose, not nearly so thick +and dense as in the preceding species. The last and thinnest terminal +branches are prolonged into denticulate, zigzagged, radial filaments, which +bear at their distal end an anchor with two recurved teeth (similar to +_Coelodrymus ancoratus_, Pl. 121, figs. 9, 10). + +_Dimensions._--Diameter of the spongy spherical mantle 3 to 3.2, of the +central valves 0.24. + +_Habitat._--Equatorial Atlantic, Station 347, depth 2250 fathoms. + + + +Family LXXXV. #COELOGRAPHIDA#, n. fam. (Pls. 122, 126-128). + +_Definition._--PHAEODARIA with a bivalved lattice-shell, composed of two +hemispherical valves, a dorsal and a ventral. A conical cupola or a +helmet-shaped galea arises on the apical pole of each valve, therefore on +the opposite poles of the sagittal axis. The cavity of the galea +communicates with the sagittal rhinocanna, a peculiar nasal tube, which +rests upon the valve, and is connected with the galea by a simple or double +frenulum; its opening being directed towards the proboscis. Three or more +branched hollow radial tubes arise from each valve, and are symmetrically +disposed. Sometimes their branches form an outer bivalved mantle. The +central capsule is so enclosed between the two inner valves, that its three +openings lie in the open frontal fissure between them. + +The family #Coelographida#, the last family of the PHAEODARIA, exhibits the +highest degree of morphological development, not only in this group, but +among all Radiolaria. They attain also the greatest size of all members of +the class, since the diameter of their body is sometimes more than 20 mm., +and in a few species even more than 30 mm. The complexity of their +structure attains at the same time such a high degree, that they may be +regarded as the most complicated, and (in a morphological sense) as the +most highly developed of all Protozoa. Nevertheless their body always +remains a single cell, {1740}and is closely allied to the preceding +Coelodendrida; they differ from the latter mainly in the development of a +peculiar new organ, the "rhinocanna," or "nasal tube." This is a hollow +tube placed in the sagittal plane, arising from the base of each galea, and +is connected with its apex by a simple or double frenulum. Between the oral +openings of the two opposed rhinocannae (one dorsal and one ventral) lies +the proboscis of the central capsule. + +The first observed species of Coelographida was _Coelographis gracillima_, +some parts of which (but not the entire skeleton) were figured in my +Monograph (1862, Taf. xxxii. figs. 2, 3). But I confounded these with +_Coelodendrum gracillimum_, in the branched hollow trees of which the +fragments of the former were entangled. I detected this error afterwards, +when I had the opportunity of the observing some complete specimens. The +first description of a complete skeleton was given in 1882 by O. Buetschli, +who examined a large specimen of _Coelothamnus davidoffii_, captured by +Davidoff in the Mediterranean (Zeitschr. f. wiss. Zool., Bd. xxxvi. p. 486, +Taf. xxxi.). In the rich collection of the Challenger I was able to +distinguish not less than nine genera and twenty-six species of +Coelographida, but the majority of their large and most fragile skeletons +were more or less injured, or quite broken. It was, therefore, of the +highest importance for the minute study of this difficult group, that Dr. +John Murray, during his expedition to the Faeroee Channel (in 1882, in +H.M.S. "Triton"), discovered in the Gulf Stream the beautiful _Coeloplegma +murrayanum_, and brought up home hundreds of well-preserved specimens (Pl. +127). Only by the complete examination of this excellent material it was +possible to answer many difficult questions as to their morphology, and to +correct the errors in my description and in that of Buetschli. + +We divide the family Coelographida into two rather different subfamilies, +which may afterwards be separated as two divergent families, the +Coelotholida (Pl. 122) and Coeloplegmida (Pls. 126-128). Both groups may be +easily distinguished at a glance, since the numerous branches, arising from +the hollow radial tubes, remain constantly free and independent in the +former, and represent a spiny thicket, whilst in the latter they constantly +become united, and by anastomosing form a peculiar "mantle," or outer +envelope of delicate network. But besides, there are other and more +important differences between the two groups. The peculiar hollow tube, +arising from the base of the galea on each valve, which is filled with +phaeodella, and which we call the rhinocanna, develops in the Coelotholida +on its open mouth two paired lateral frenula (right and left), which +connect it (like two lateral bridges) with the base of two paired hollow +main tubes (the "frontal tubes"). In the Coelospathida, however, the mouth +of the rhinocanna develops a single odd frenulum only (in the sagittal +plane), and is connected by it with the base of an odd, single, hollow main +tube, directed forwards, the "nasal style." + +The central bivalve lattice-shell, from which the galea and the tubes +arise, exhibits in {1741}the Coelographida essentially the same form and +structure as in the preceding Coelodendrida. The only (but important) +difference between them is indicated by the constant presence of the +peculiar rhinocanna in the former, whilst this is always absent in the +latter. The two valves of the shell, dorsal and ventral, are either +hemispherical or somewhat flatter, sometimes nearly cap-shaped, and formed +of an extremely delicate and irregularly fenestrated plate of silica, as in +the Coelodendrida. As in the latter, so also in the Coelographida both +valves are of similar form and usually of equal size, but sometimes the +dorsal is a little smaller than the ventral valve. The remarkable +difference which Buetschli describes in his _Coelothamnus davidoffii_, and +the inverse origin of the three tubes in both valves (_loc. cit._, Taf. +xxxi; figs. 2, 4), depends upon an error of observation, produced by the +artificial inversion of one valve, and the dislocation of their natural +arrangement. The valves are never in direct contact, but separated by the +equatorial fissure or girdle-cleft, in which the girdle zone of the +enclosed central capsule and its three openings lie freely (Pl. 127, figs. +4, 5; Pl. 128, fig. 2). The free margins of both valves, which are opposite +to one another, and bound the girdle-cleft, are always equidistant, so that +the cleft in the whole equatorial circumference is of equal breadth. The +margins are usually irregularly denticulate, sometimes armed with longer +bristles (Pl. 127, fig. 8), more rarely smooth (fig. 5). The delicate +lattice-work of the valves is always irregular and very variable, usually +with numerous small and unequal pores, sometimes rudimentary, so that the +valves appear partly solid and hyaline. The size of the valves is usually +between 0.2 and 0.5 (in diameter). + +The galea (_g_) or the apical cupola, which arises from the vaulted apex of +each valve (or its sagittal pole) is more developed in the Coelographida +than in the preceding Coelodendrida, and differs from the latter in the +peculiar rhinocanna arising from its base, and in the single or double +frenulum, connecting the open mouth of the rhinocanna with the odd or +paired main tube arising from the galea. The two opposite galeae lie +therefore on the poles of the sagittal axis of the bivalve shell, and are +so symmetrically disposed in the sagittal plane, that the open mouths of +their rhinocannae are directed towards the oral pole of the main axis, and +nearly come in contact with the proboscis arising from the radiate +operculum of the central capsule (Pl. 127, figs. 4, 5). + +The size and form of the galea are very variable, even in one and the same +species. The volume of its cavity is generally about as great as that of +the hemispherical valve from which it arises, sometimes larger, at other +times smaller. Its fundamental form is constantly dipleuric or bilateral, +since the radial hollow tubes arise symmetrically on both its sides, and +the rhinocanna proceeding from its base determines the sagittal plane. +Usually the galea has the form of a vaulted helmet, the convex crest of +which is inclined towards the mouth (Pl. 127, figs. 4, 5, 8, 9). Its +anterior or apical part is broad and truncated in the Coelotholida, more or +less conical in the Coelospathida; sometimes it assumes nearly the form of +a bilateral three-sided pyramid, at other times it is more +{1742}pear-shaped (Pls. 126-128). The thin siliceous wall of the galea has +the same irregular and delicate network as the valve from which it arises, +and sometimes the small irregular pores are also here reduced, so that the +wall becomes partly solid. In some cases the thin, solid, siliceous plate +of the galea and of the valve is covered by an irregular delicate network +of crests; the dimples between these crests may be easily confounded with +true pores. + +The cavity of the galea is filled with phaeodella and does not communicate +with the cavity of the shell-valves, nor with the cavity of the radial +tubes filled by jelly; it is closed towards the latter and the former by a +thin solid plate of silex. Buetschli (1882, _loc. cit._, p. 488) describes +in _Coelothamnus_ a large circular opening (Taf. xxxi. figs. 2_a_, 4_a_), +and states that this is a direct communication between the cavities of the +valves and of their galeas which are called by him "der dreiseitige +kastenfoermige Aufsatz" ([epsilon]). This error was caused by the fact that +he observed the valves from the apical face only. The apparent opening of +communication does not exist, and is the optical section of the rhinocanna, +the shortened walls of which he describes as "trapezfoermige Kiesellamelle" +([gamma]); the two lateral edges of the latter ("die seitlichen Zipfel," +[delta]) are the paired frenula, which connect the open mouth of the +rhinocanna with the base of the two frontal tubes. + +The "rhinocanna or nasal tube" (Pl. 126, figs. 1, 4; Pl. 127, figs. 4-9_t_) +is a very remarkable organ which is common to all Coelographida (without +any exception), and distinguishes them markedly from all the other +Radiolaria, and particularly from the closely allied Coelodendrida in which +we find no trace of it. The rhinocanna is a cylindrical or three-sided +prismatic hollow tube, which lies in the sagittal plane, on the outer +surface of each valve, arises from the base of the galea, and is directed +towards the proboscis of the central capsule. The two opposite rhinocannae +open on each side of the latter (Pl. 127, figs. 4-9_m_), and usually this +"nasal mouth" or the anterior opening of the nose is somewhat dilated or +even funnel-shaped. The posterior opening of the nose passes directly over +into the base of the cavity of the galea. + +Usually the rhinocanna is densely filled up by dark phaeodella, which enter +by this channel into the cavity of the galea (Pl. 127, figs. 4, 5, 9). +Sometimes the entire phaeodium is enclosed in the two galeae and their +rhinocannae (figs. 5, 9), whilst at other times a great part of the +phaeodium lies outside of their cavities, and surrounds the proboscis of +the mouth, or even the anterior half of the central capsule (fig. 4). The +length of the cylindrical rhinocanna is usually about equal to that of the +galea, whilst the diameter of the latter is from three to five times as +great as that of the former. The structure of the thin wall is the same in +both. The fine reticulation (fig. 8) is produced either by true, very small +and irregular pores, or by a fine network placed on the solid thin wall. We +may distinguish on each rhinocanna an outer or distal convex face, which is +opposite to the proximal concave face of the galea, and an inner concave or +proximal face, which rests immediately upon the convex outer face of the +shell-valve; a thin solid lamella of {1743}silica here completely separates +the cavities of the valve and of the rhinocanna resting upon it. + +The "frenula or nasal suspensoria" (Pl. 127, figs. 4-9_b_) are thin +ligaments of silica, which connect the nasal mouth (_m_) with the base of +the main tubes arising from the galea; they are, therefore, also common to +all Coelographida, and an exclusive and marked attribute of this family. +They are, however, different in the two subfamilies of this group, +corresponding to the different origin of the odd or paired main tubes. In +the Coeloplegmida (Pls. 126-128) from the apex of each galea arises an odd +main style, the nasal style (_g_ 1), and its base is connected with the +nasal mouth by an odd frenulum (_b_). In the Coelotholida however (Pl. 122) +the large nasal odd style is always wanting, and there arise two paired +frontal tubes from the two corners of the truncate frontal face of the +galea; therefore two paired frenula are developed (a right and a left), and +these, converging towards the nasal mouth, connect its distal corner with +the base of the two frontal tubes. + +The odd frenulum of each valve of the Coeloplegmida lies therefore in the +sagittal plane, whilst the two paired frenula of the Coelotholida lie on +both sides of it, to the right and left. The frenula seem to be supporting +columellae or pillars, which support the fragile skeleton, and mainly +effect a fixed prop for the fragile galea. In the Coelotholida the frenula +are often rather broad and irregularly fenestrated lamellae of silica (Pl. +122, fig. 2), whilst in the Coeloplegmida they are usually thin ligaments, +fenestrated only at the broadened ends, which are inserted inside on the +distal apex of the nasal mouth, and outside on the base of the nasal main +styles. + +The large hollow tubes which arise from the galea of all Coelographida, are +very variable in number, size and shape, but are always richly branched and +symmetrically arranged in the dorsal and the ventral valve of the shell. +They exhibit an important difference in the two subfamilies of the group; +in the Coelotholida all the branches, and also the thin terminal ramules, +are free, without any junction; in the Coeloplegmida, however, they +communicate by frequent anastomoses, and the connected terminal ramules +form on the surface of the calymma an outer lattice-mantle of very delicate +network. Another marked difference between the two families is indicated by +the origin and site of those main tubes which are connected with the +rhinocanna by a frenulum. In the Coeloplegmida an odd, very large main tube +(the nasal style) arises from the anterior apex of each galea and bears on +its base an odd frenulum. This nasal style and its frenulum is altogether +wanting in the Coelotholida, where two paired main tubes (the frontal +tubes) arise from the lateral corners of the truncate anterior side of the +galea, and are connected with the mouth of the rhinocanna by two paired +convergent lateral frenula. + +We distinguish in all Coelographida two different forms of hollow branched +tubes, which we will call "brushes" and "styles." The brushes are +dichotomously branched from the base, not verticillate; their distal +ramules remain separate in the Coelotholida {1744}and compose the spiny +surface, of the peculiar "fork-thicket" whilst in the Coelographida they +become connected by frequent anastomoses and form the outer +"lattice-mantle." The styles however are much longer projecting over the +surface of the thicket or the mantle, and are not dichotomously branched, +but verticillate, or armed with cruciate or alternately cruciate pairs of +branches; the larger branches of the styles may be again dichotomously +branched like the brushes; whilst the free prominent parts of the styles +are always verticillate or cruciate-pinnate. The brushes are identical with +the hollow tubes of the Coelodendrida, whilst the styles are peculiar forms +of apophyses, wanting in the latter. + +The minimum number of hollow tubes which arise from each valve is three, +and these are probably homologous with the three primary tubes of the +Coelodendrida. Two of these are paired (right and left), whilst the third +is odd and lies in the sagittal plane; they have the same position as in +the tripodal NASSELLARIA, and may therefore bear the same names, the two +paired anterior or pectoral tubes being divergent forwards, the odd or +caudal tube being bisected backwards (so in the Coelotholida, Pl. 121). The +odd caudal tube (probably identical with the odd tube of the Coelodendrida) +is always a brush, dichotomously branched, and never prolonged into free +style. The two paired frontal or pectoral tubes, however are usually +prolonged into two long verticillate styles. The basal origin also of these +three primary tubes is different. The two pectoral or anterior paired tubes +always arise from the galea itself whilst the posterior odd or caudal tube +usually arises behind the galea from the valve (Pl. 127, figs. 4-8, _g_ 6). + +Since these three primary tubes the odd caudal and the paired pectoral, are +probably homologous in all Coelographida and Coelodendrida, they have a +great morphological importance, similar to the three primary feet of the +NASSELLARIA. All other tubes arising from the valves must be regarded as +secondary apophyses, since they are not constant in all members of the two +families, but present only in some of them. All the Coelotholida observed +(a small number of species only) possess no secondary tubes, but only the +three primary; whilst all Coeloplegmida possess one or more secondary +tubes, and one of these is constant, viz., the odd nasal style, directed +towards the mouth, and arising as the foremost from the apex of the galea +(Pl. 127, figs. 4-8, _g_ 1). + +The maximum number of tubes observed, which arise from each valve in the +Coeloplegmida, is eleven; five of these are odd and placed in the sagittal +plane of the body, viz.:--(A) the primary caudal tube (Pl. 127, figs. 4-8, +_g_ 6); (B) an odd procaudal tube, arising between the caudal and the +sagittal tube; (C) the sagittal tube, placed either in the sagittal axis of +the body or near it (often prolonged into a sagittal style, Pl. 128, fig. +1); (D) an odd postnasal tube, arising between the sagittal and the nasal +tube; (E) the odd nasal tube, constant in all Coeloplegmida, and connected +at its base by the odd frenulum with the rhinocanna (Pl. 127, figs. 4-8, +_g_ 1). All other tubes occurring in the Coeloplegmida are paired, and +symmetrically arranged on both sides of the sagittal {1745}plane, at right +and left; their maximum number is three pairs, viz.:--(F) the paired +pectoral tubes (as the foremost), directed forwards; (G) the paired frontal +or lateral tubes, placed either in the frontal axis of the valve, or in a +neighbouring axis, directed towards the right and left pole (Pl. 127, figs. +4-8, _g_ 4 and _g_ 5); (H) the paired tergal tubes, directed backwards +(constant in all Coeloplegmida). The origin of these tubes is rather +variable, since they arise in nearly allied species, sometimes +independently of one another, at other times united at the base. But a +closer comparison of them in the different species will demonstrate their +homology, caused by constant heredity. + +The terminal ramules of the brushes, which form the subspherical +"fork-thicket" in the Coelotholida, the outer "lattice-mantle" in the +Coeloplegmida, are constantly armed at the distal ends either with +spathillae or with anchor-pencils, bunches of those most elegant spinulate +threads, which bear at the free end an anchor, or a whorl of two, three, or +four recurved teeth (Pl. 122, fig. 8; Pl. 127, fig. 10; Pl. 128, figs. 1, +6). The pencils are usually dichotomously branched, their threads zig-zag +or delicately serrate, often armed with very small recurved denticles, and +the anchor teeth (commonly three or four) are usually smooth on the convex +outer, serrate on the concave inner edge. The entire surface of the +subspherical thicket in the Coelotholida, and of the polyhedral +lattice-mantle in the Coeloplegmida, is armed with thousands of those most +elegant spathillae, or anchor-pencils. + +The "fork-thicket" of the Coelotholida is identical with that of the +Coelodendrida, and is composed only of the innumerable dichotomous branches +of the hollow tubes. It envelops the two central valves and the enclosed +central capsule in the same way as in the Coelodendrida. But the +Coelotholida differ from these latter in constantly possessing a rhinocanna +and two frenulae. The entire form of this thicket, which in the few species +observed was never complete, but always more or less destroyed, is usually +probably subspherical or polyhedral, sometimes cordate or kidney-shaped. +Its surface is densely studded with thousands of spathillae. Its diameter +is about four to eight times as great as that of the enclosed bivalve +shell. + +The "lattice-mantle" of the Coeloplegmida, which replaces in this subfamily +the fork-thicket of the Coelotholida, is always produced by the anastomoses +of the distal ramules of the brushes, and of those branches of the styles +which do not proceed over the surface of the mantle. Its network is always +very irregular, and composed of polygonal meshes of very different sizes. +Usually it is quite simple, and may be compared with the cortical shell of +the Disphaerida. More rarely it is more or less spongy. Its surface is +densely studded with thousands of spathillae or anchor-pencils. The entire +form of the lattice-mantle is always symmetrically polyhedral, since its +dorsal and ventral halves are symmetrically developed on both sides of the +equatorial plane, and therefore correspond perfectly to the enclosed +smaller halves of the central bivalve shell. The two valves of the +lattice-mantle (dorsal and ventral valves) are never really united and +grown together, {1746}but are in loose contact in the equatorial plane; +here the free edges of both valves catch into one another by means of free +ramules (Pl. 128, figs. 1, 7). This loose connection is similar to what +occurs in the Conchopsida (or in the Concharida with dentate edges), but +never so regular. The special form of the polyhedral lattice-mantle depends +on the number, arrangement, and development of the styles, which proceed +over its surface; it preserves the polyhedral form of the calymma, on the +surface of which it is deposed. + +The characteristic styles of the Coelographida (which are never found in +the preceding Coelodendrida) are longer hollow tubes, symmetrically +disposed on both valves. They are prominent over the surface of the +fork-thicket in the Coelotholida, of the lattice-mantle in the +Coeloplegmida. They bear in these latter a peculiar terminal coronet on +their distal end, whilst in the former this end is armed with large pencils +of spathillae. The styles may be forked once or twice at their base, but in +their greatest part they are verticillate, and not dichotomously branched +like the brushes. The lateral branches of the styles are usually very +numerous and regularly cruciate in alternating opposite pairs. In the odd +nasal style, _e.g._, the first and third pairs of opposite lateral branches +usually lie in the frontal plane, the second and fourth in the sagittal +plane, perpendicular to the former, and so on. A similar regular +disposition of the lateral branches is found also in other styles, but not +in all. There are certain styles in which the lateral branches are not +opposite in pairs, but alternate or verticillate, and others in which they +represent unequal branches of forks, so that each single segment of the +branched style represents the stouter branch of a fork, and the +appertaining lateral branch the thinner branch of the fork. Further +accurate examinations are required to recognise the different laws of the +ramification of the styles in the different forms of Coelographida. The +lateral branches of the styles are usually again dichotomously branched +inside the lattice-mantle, and their distal ends pass over into its +network. But the verticillate or cruciate branches, which arise from the +free part of the styles outside the lattice-mantle, are always armed with +the same elegant pencils of spathillae which cover the surface of the +fork-thicket in the Coelotholida, the surface of the lattice-mantle in the +Coeloplegmida. These pencils also are often regularly opposite in pairs, +and the pairs alternate in two planes perpendicular one to another (Pl. +128, figs. 1, 4). + +The terminal coronets are peculiar ornaments which protect the distal ends +of the styles in the Coeloplegmida, whilst in the Coelotholida these are +armed with the usual pencils of spathillae (Pl. 122, fig. 8). Each coronet +is usually produced by the double, triple, or quadruple furcation of the +free distal end of the style; therefore composed of four, eight, or sixteen +terminal branches, which, on account of their peculiar form and function, +we may call "fingers." More rarely the ramification of the coronets is more +or less irregular, and sometimes the number of the fingers exceeds twenty +or even thirty. + +In the majority of species eight fingers are regularly disposed (Pl. 127, +figs. 1-3; Pl. 128, figs. 1-8). Often too sixteen occur, rarely four only. +Sometimes the fingers {1747}are placed nearly in one plane and form a hand. +The form of the fingers is very variable and most characteristic of the +individual species. Very often they have the shape of a human finger, and +are smooth, spinulate, or armed with recurved hooks. The distal end of each +finger often again bears a small coronet or a spathilla (Pl. 128, figs. +5-9), and sometimes it is arrow-shaped (Pl. 126, fig. 2_a_). All these +apophyses of the terminal coronets as well as the anchor-pencils of the +mantle and the finest branches of the tubes, are hollow and filled up by +jelly. + +The different number and arrangement of the styles offers the best means +for the distinction of genera in the Coelographida. The minimum number is +six (_Coelographis_, Pl. 126, fig. 1), the maximum number sixteen +(_Coelothamnus_, Pl. 122, fig. 3, and _Coelagalma_, Pl. 126, fig. 4). Since +the arrangement of the styles in both valves is constantly symmetrical, the +fundamental form of the whole body is in all Coeloplegmida "amphithect," as +in the _Ctenophora_. The longitudinal or main axis of the body is vertical, +with two distinct poles; the proboscis of the central capsule and the two +rhinocannae are directed upwards, towards the oral pole; the caudal tube of +each valve is directed downwards, towards the aboral pole. The two other +axes of the body are unequal, horizontal, and perpendicular one to the +other; each has two equal poles. On the poles of the sagittal axis lie the +galeae of the dorsal and ventral valves; on the poles of the frontal axis +lie the two secondary openings or parapylae of the central capsule. The +frontal fissure or the large cleft between the dorsal and ventral valves of +the skeleton lies in the vertical frontal plane of the body, which is +perpendicular to the vertical sagittal plane; the equatorial plane, +however, is horizontal. + +The _central capsule_ of the Coelographida exhibits the same shape and +position as in the preceding Coelodendrida. It is subspherical, slightly +depressed in the direction of the main axis, and lies enclosed between the +two central valves of the lattice-shell. Its three constant openings lie in +the frontal plane, and therefore in the frontal fissure between the two +valves. The astropyle, or the main-opening of the capsule, lies on the oral +pole of the main axis, and its radiate operculum (_d_) is directed upwards; +the curved proboscis arising from it (_o_) is prominent between the mouths +of the two opposed rhinocannae. The two lateral parapylae or accessory +openings lie on both sides of the aboral pole, on the right and left (Pl. +127, figs. 4-6). The large spheroidal or somewhat lenticular nucleus (_n_) +is usually about half as broad as the capsule, and contains numerous +nucleoli. The protoplasm around the nucleus contains many vacuoles, and in +the oral part of the capsule (between nucleus and operculum) often numerous +groups of crystals (Pl. 127, figs. 4-6_k_, 7). The double membrane of the +central capsule exhibits the same shape as in the other PHAEODARIA. + +The calymma, or the extracapsular jelly-veil, is in the Coelographida very +voluminous, and includes the entire skeleton, the fork-thicket of the +Coelotholida, the lattice-mantle of the Coeloplegmida, and also the +prominent large styles. Only the distal ends of the {1748}latter (with the +terminal coronets), and the anchor pencils, covering the surface of the +thicket and the mantle, seem to project over the surface of the calymma. +The entire form of the latter is therefore a symmetrical polyhedron. The +phaeodium fills up a small part only of the calymma, and is usually +enclosed in the two galeae and their rhinocannae (Pl. 127, figs. 5, 9), but +often also a part of the phaeodium is scattered around the oral half of the +central capsule. + +_Synopsis of the Genera of Coelographida._ + + ------------------------------------------------------------------------- + I. Subfamily Coelotholida. + Rhinocanna of each valve with two paired lateral frenula. The distal + ends of the dichotomous brushes are not united by anastomoses, and + form an outer bivalved fork-thicket. + ------------------------------------------------------------------------- + Eight paired styles (four on each valve), 731. _Coelotholus_. + + Twelve paired styles (six on each valve), 732. _Coelothauma_. + + Sixteen paired styles (eight on each valve), 733. _Coelothamnus_. + ------------------------------------------------------------------------- + II. Subfamily Coeloplegmida. + Rhinocanna of each valve with an odd sagittal frenulum. The distal + ends of the dichotomous brushes are united by anastomoses, and form + an outer bivalved lattice-mantle. + ------------------------------------------------------------------------- + Mantle with six styles. { One odd and two paired + { styles on each valve, 734. _Coelographis_. + + Mantle with eight styles. { Two odd and two paired + { styles on each valve, 735. _Coelospathis_. + + Mantle with ten styles. { One odd and four paired + { styles on each valve, 736. _Coelodecas_. + + Mantle with twelve { Two odd and four paired + styles. { styles on each valve, 737. _Coelostylus_. + + Mantle with fourteen { One odd and six paired + styles. { styles on each valve, 738. _Coeloplegma_. + + Mantle with sixteen { Two odd and six paired + styles. { styles on each valve, 739. _Coelagalma_. + + + +Subfamily 1. COELOTHOLIDA, Haeckel. + +_Definition._--#Coelographida# with two paired lateral frenula on each +galea, and with free terminal branches on the hollow radial tubes, without +an external lattice-mantle. Eight to sixteen long styles are prominent over +the surface of the fork-thicket, which is composed of the caudal brush and +the dichotomous basal branches of the styles. + + + +Genus 731. _Coelotholus_,[347] n. gen. + +_Definition._--#Coelographida# with two paired lateral frenula on each +galea, without external lattice-mantle, armed with eight styles (two pairs +of styles on each valve). + +{1749}The genus _Coelotholus_ and the two following genera form together +the subfamily Coelotholida, the hollow tubes of which do not communicate by +anastomosing branches, and therefore form no lattice-mantle, as in the +following subfamily Coeloplegmida. Another important difference between +these two subfamilies of Coelographida is found in the arrangement of the +main tubes and their connection with the rhinocanna. In all Coelotholida a +pair of divergent frontal styles arise from the truncate oral side of each +galea, and are connected with the mouth of the rhinocanna by two lateral +convergent paired frenula (right and left); whereas the characteristic odd +nasal style, which in all Coeloplegmida arises from the sagittal apex of +each galea and is connected with the mouth of the rhinocanna by an odd +sagittal frenulum, is always wanting. The total number of long verticillate +styles, which project over the outer surface of the fork-thicket, is eight +in _Coelotholus_, whilst it is twelve in _Coelothauma_, and sixteen in +_Coelothamnus_. The two latter may be derived from _Coelotholus_, as the +common ancestral genus of this subfamily. + + +1. _Coelotholus octonus_, n. sp. (Pl. 122, figs. 1, 2). + +Eight styles of equal length, regularly zig zag, twice as long (in their +free part) as the diameter of the loose fork-thicket. Anchor-pencils +gradually tapering from the proximal towards the distal end. Each of the +four primary frontal tubes (to the right and left of each valve) is simply +forked, and the pectoral (anterior) branch of each tube is so diametrically +opposed to the tergal (posterior) tube of the other side, that they form +together a double cross. + +_Dimensions._--Diameter of the whole body 12, of the fork-thicket 2.5. + +_Habitat._--South-Eastern Pacific, Station 300, depth 1375 fathoms. + + +2. _Coelotholus cruciatus_, n. sp. + +Eight styles of equal length, straight, twice as long (in their free part) +as the diameter of the dense fork-thicket. Anchor-pencils of about equal +size throughout their whole length. Each of four primary frontal tubes is +divided into two equal, widely divergent branches; the anterior branches of +the right side are diametrically opposed to the posterior branches of the +left side, so that all eight together form a double cross. + +_Dimensions._--Diameter of the whole body 20, of the fork-thicket 4.0. + +_Habitat._--South-Western Pacific (off Sydney), Station 164A, depth 1200 +fathoms. + + +3. _Coelotholus ancoratus_, n. sp. + +Eight styles of different lengths, slightly curved. Anchor-pencils +gradually tapering from the proximal to the distal end. Each of the four +primary frontal tubes is divided into two divergent {1750}branches of +different lengths; the anterior (or pectoral branch) twice as long (in the +free part) as the diameter of the fork-thicket, the posterior (or tergal +branch) three times as long. + +_Dimensions._--Diameter of the whole body 20, of the fork-thicket 3.2. + +_Habitat._--Indian Ocean (Sunda Strait), Rabbe, surface. + + + +Genus 732. _Coelothauma_,[348] Haeckel, 1879, Sitzungsb. med.-nat. +Gesellsch. Jena, Dec. 12, p. 6. + +_Definition._--#Coelographida# with two paired lateral frenula on each +galea, without external lattice-mantle, armed with twelve styles (three +pairs of styles on each valve). + +The genus _Coelothauma_ differs from the preceding _Coelotholus_, its +ancestral form, in the possession of twelve long, prominent styles, six of +which are opposite in three pairs on each valve. In the single species +observed each of the four main tubes (opposite in pairs on the frontal +corners of the two galeae) is simply forked, as in _Coelotholus_; but +whilst in this latter all eight styles remain simple, in _Coelothauma_ the +anterior (or pectoral) branch only is simple, the posterior (or tergal) +branch is again forked. + + +1. _Coelothauma duodenum_., n. sp. (Pl. 122, figs. 3-5). + +Twelve styles straight, of different lengths. Two short bilateral main +tubes arise opposite in pairs from the two frontal corners of each galea, +and are divided into an anterior and posterior branch. The anterior or +pectoral branch is simple, and twice as long as the diameter of the +fork-thicket. The posterior or tergal branch is again forked near the base, +and its two divergent branches are three times as long as the diameter of +the fork-thicket. All twelve styles are densely studded with anchor-pencils +of nearly equal size. + +_Dimensions._--Diameter of the whole body 21, of the fork thicket 3.5. + +_Habitat._--South-Western Pacific (east of New Zealand), Station 169, depth +700 fathoms. + + + +Genus 733. _Coelothamnus_,[349] Haeckel, 1879, Sitzungsb. med.-nat. +Gesellsch. Jena, Dec. 12, p. 6. + +_Definition._--#Coelographida# with two paired lateral frenula on each +galea, without external lattice-mantle, armed with sixteen styles (four +pairs of styles on each valve). + +The genus #Coelothamnus# differs from its ancestral form, _Coelotholus_, in +the duplication of the number of long verticillate styles, which are +prominent over the surface of the {1751}dense fork-thicket. Whilst in +_Coelotholus_ each frontal main tube (arising from the frontal corner of +the galea at right and left) is divided into an anterior or pectoral, and a +posterior or tergal style, in _Coelothamnus_ each of these two divergent +main styles is again forked, so that the total number of projecting and +radially diverging styles amounts to sixteen. One Mediterranean species of +this genus, _Coelothamnus davidoffii_, has been already described by +Buetschli in 1882 (Zeitschr. f. wiss. Zool., vol. xxxvi. p. 486, Taf. +xxxi.). Though its description on the whole is accurate, some important +errors, which may be here corrected, are to be met with. The two central +valves of the lattice-shell (dorsal and ventral) are symmetrically equal in +size and in form, as in all other Coelographida; the different forms and +the inverse arrangement of the two valves, described by Buetschli (pp. 488, +491), were effected by an artificial dislocation and inversion. The +peculiar opening [alpha], which, according to his opinion, was supposed to +bring about a direct communication between the cavities of the galea and +its valve, is in reality the optical section of the rhinocanna, the two +convergent frenula of which ([gamma]) he figured, but did not recognise. +_Coelothamnus_ attains the greatest size among all Radiolaria; the diameter +of the body in _Coelothamnus maximus_ amounts to 33 mm. + + +1. _Coelothamnus bivalvis_, n. sp. (Pl. 122, figs. 6-9). + +Sixteen styles all of equal length, about three times as long (in their +free part) as the diameter of the dense fork-thicket. The size of the +anchor-pencils tapers from the proximal to the distal end. Each of the four +primary frontal tubes (which arise in opposite pairs from the frontal +corners of the two galeae) is twice forked, and so produces four styles. + +_Dimensions._--Diameter of the whole body 18, of the fork-thicket 2.4 to +3.0. + +_Habitat._--North Atlantic, Canary Islands, Station 354, surface. + + +2. _Coelothamnus davidoffii_, Buetschli. + + _Coelothamnus davidoffii_, Buetschli, 1882, Zeitschr. f. wiss. Zool., + vol. xxxvi. p. 486, Taf. xxxi. + +Sixteen styles all of equal length (?), about four times as long (in their +free part) as the diameter of the fork-thicket. The size of the +anchor-pencils is nearly equal throughout their entire length. (Compare the +careful description of this species by Buetschli.) + +_Dimensions._--Diameter of the whole body 15, of the fork-thicket 1.8. + +_Habitat._--Mediterranean (Villafranca, near Nice), Davidoff, surface. + + +3. _Coelothamnus sedecimalis_, n. sp. + +Sixteen styles straight, of different sizes. The pectoral or anterior +branch of each frontal main tube is simple, and twice as long as the +diameter of the large fork-thicket. The tergal or posterior branch is +forked at the base, and its anterior branch is again forked in the middle +part, so that three {1752}long divergent styles arise from each tergal +tube. The hindermost of these is the longest, three times as long as the +diameter of the fork-thicket. All anchor-pencils have nearly equal size. + +_Dimensions._--Diameter of the whole body 22, of the fork-thicket 5.2. + +_Habitat._--South Pacific, Station 166 (west of New Zealand), depth 275 +fathoms. + + +4. _Coelothamnus maximus_, n. sp. + +Sixteen styles straight, of different sizes. The four frontal main tubes +are already forked at the base, so that from each frontal corner of the two +galeae two divergent tubes, an anterior or pectoral and a posterior or +tergal, arise. Each of these is again forked, and each branch prolonged +into a very long verticillate style. The hindermost style of each side is +the longest, twice as long as the foremost, and one and a half times as +long as the two intermediate styles. The size of the anchor-pencils +decreases in the distal third of the styles. + +_Dimensions._--Diameter of the whole body 32, of the fork-thicket 7.5. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + + +Subfamily 2. COELOPLEGMIDA, Haeckel. + +_Definition._--#Coelographida# with an odd sagittal frenulum on each galea, +and with an external bivalved lattice-mantle, produced by the anastomosing +branches of the hollow radial tubes. Six to sixteen long styles are +prominent over the surface of the mantle, and bear terminal coronets. + + + +Genus 734. _Coelographis_,[350] n. gen. + +_Definition._--#Coelographida# with an odd sagittal frenulum on each galea +and an outer lattice-mantle, armed with six styles (one odd and two paired +styles on each valve). + +The genus _Coelographis_ is the simplest form of the Coeloplegmida, or of +those Coelographida in which the branches of the arborescent tubes are +united on the surface of the calymma, and form a delicate bivalved +lattice-mantle. In all these Coeloplegmida an odd nasal main style is +developed on the apex of the galea, and this is connected by an odd +sagittal frenulum with the mouth of the rhinocanna, _Coelographis_ differs +from the other Coelographida in the minimum number of coronal styles, viz., +three on each valve, an odd anterior (nasal) and two paired posterior +(tergal). + + +1. _Coelographis regina_, n. sp. (Pl. 126, figs. 1_a_-1_c_). + +Shell-mantle twice as long as broad, its frontal perimeter isosceles +triangular, with a triangular excision at the base, its sagittal perimeter +slenderly ovate. Nasal odd style twice as long as the {1753}paired tergal +styles, the former with ten to twelve, the latter with five to six +alternate-cruciate pairs of lateral branches. Terminal coronets (on the +free distal ends of the styles) palmate, with ten to twelve spinulate, +irregular, finger-shaped branches (fig. 1_d_). + +_Dimensions._--Length of the shell 5.6, breadth 2.7. + +_Habitat._--South-Eastern Pacific (off Juan Fernandez), Station 297, depth +1775 fathoms. + + +2. _Coelographis sagittella_, n. sp. + +Shell-mantle one and a half times as long as broad, its frontal perimeter +arrow-shaped, isosceles triangular, with a deep concave excision at the +base, its sagittal perimeter slenderly ovate. Nasal odd style one and a +half times as long as the paired tergal styles, the former with fourteen to +sixteen, the latter with eight to nine verticils of branches. Terminal +coronets three times forked, with eight subregular, broad and spinulate, +finger-shaped branches. + +_Dimensions._--Length of the shell 6.4, breadth 4.2. + +_Habitat._--Central Pacific, Station 271, depth 2425 fathoms. + + +3. _Coelographis hexastyla_, n. sp. + +Shell-mantle one and a half times as long as broad, very similar to the +preceding species, its frontal perimeter isosceles triangular, with a flat +basal excision. Nasal odd style one and a third times as long as the paired +tergal styles, the former with fourteen to sixteen, the latter with ten to +twelve verticils of branches. Terminal coronets with four forks in the form +of a cross, and eight divergent spinulate fingers. + +_Dimensions._--Length of the shell 4.2, breadth 3.1. + +_Habitat._--North Pacific, Station 259, depth 2225 fathoms. + + +4. _Coelographis gracillima_, Haeckel. + + _Coelodendrum gracillimum_ (_partim_) Haeckel, 1862, Monogr. d. Radiol., + Taf. xxxii. figs. 2, 3. + +Shell-mantle one and a third times as long as broad, similar to the three +preceding species, its frontal perimeter isosceles triangular. Nasal odd +style one and a half times as long as the two paired tergal styles, the +former with eleven or twelve, the latter with seven or eight pairs of +branches. Terminal coronets irregularly dichotomously branched, with twelve +to sixteen spinulate fingers. The network of the mantle is also spinulate +(_loc. cit._, fig. 3). This species was formerly confounded by me with +_Coelodendrum gracillimum_ (_loc. cit._, fig. 1), since I found a fragment +only of the former entangled in the branch-work of the latter (1859, in +Messina). Afterwards (in 1877) I observed a complete specimen in Corfu. + +_Dimensions._--Length of the shell 3.2, breadth 2.4. + +_Habitat._--Mediterranean (Messina, Corfu), surface. + + +5. _Coelographis triangulum_, n. sp. + +Shell-mantle about as long as broad, its frontal perimeter equilateral +triangular, without basal excision, with three equal straight sides. Nasal +odd style and the two paired pectoral styles nearly {1754}of equal length, +each with ten to twelve alternate-cruciate pairs of lateral branches. +Terminal coronets umbrella-shaped, composed of eight equal, simply forked +branches. + +_Dimensions._--Length of the shell 3.6, breadth 3.4. + +_Habitat._--South Pacific, Station 293, depth 2025 fathoms. + + + +Genus 735. _Coelospathis_,[351] n. gen. + +_Definition._--#Coelographida# with an odd sagittal frenulum on each galea +and an outer lattice-mantle, armed with eight styles (two odd and two +paired styles on each valve). + +The genus _Coelospathis_ differs from the preceding _Coelographis_ in the +possession of four coronal styles on each valve. Two of these are odd and +lie in the sagittal plane, viz., the constant vertical nasal style +(directed towards the mouth), and the horizontal sagittal style, which is +placed in the equatorial plane, in the sagittal axis of the body. The two +other styles are paired and identical with the tergal styles of +_Coelographis_, directed backwards, and divergent to right and left. + + +1. _Coelospathis ancorata_, n. sp. (Pl. 128, figs. 1-7). + +Shell-mantle one and a half times as long as broad, its frontal perimeter +isosceles triangular; its zonal perimeter square, its sagittal perimeter +nearly rectangular, with a concave excision on the oral side (fig. 1). Odd +nasal styles of both valves divergent in the sagittal plane (each with +fourteen to sixteen pairs of branches), three times as long as the odd +sagittal styles (each with three or four pairs) and twice as long as the +paired tergal styles (each with four to six pairs of branches). Terminal +coronets (on the free distal end of the styles) three times forked, each +with eight slender, widely divergent fingers, which are curved, zig-zag, +and armed with alternating recurved hooks; at the end of each finger a +verticil of four to six small recurved teeth (fig. 5). + +_Dimensions._--Length of the shell 2 to 3, breadth 1.2 to 2.1. + +_Habitat._--South Pacific, Station 289, depth 2550 fathoms. + + +2. _Coelospathis octostyla_, n. sp. (Pl. 128, fig. 8). + +Shell-mantle one and a third times as long as broad, very similar to the +preceding species; but differing from this in the following characters: the +odd nasal styles bear ten to twelve pairs of branches, and are twice as +long as the odd sagittal and the paired pectoral styles, which are nearly +equal in size (each with five or six pairs of branches). The eight fingers +of the terminal coronets are less divergent and curved than in the +preceding species, and each finger bears at its end a verticil of four to +six divergent, slender teeth, which are not recurved (fig. 8). + +_Dimensions._--Length of the shell 2.2 to 2.6, breadth 1.7 to 1.9. + +_Habitat._--Central Pacific, Stations 271 to 274, depth 2350 to 2750 +fathoms. + + +{1755}3. _Coelospathis octodactyla_, n. sp. (Pl. 128, fig. 9). + +Shell-mantle about as long as broad, in the frontal perimeter nearly +isosceles triangular, very similar to the two preceding species; it differs +from them in the following characters: all eight styles have nearly equal +size, and each bears six to eight pairs of branches. The eight fingers of +the terminal coronets diverge nearly in one plane, and are not curved in a +zigzag manner, but armed with alternate, slender, recurved hooks, which are +larger than in the two preceding species, and geniculate at the base; the +distal end of each finger bears a verticil of eight to ten very small +divergent teeth, which are not recurved (fig. 9). + +_Dimensions._--Length of the shell 2.4, breadth 2.2. + +_Habitat._--North Pacific, Station 252, surface. + + + +Genus 736. _Coelodecas_,[352] n. gen. + +_Definition._--#Coelographida# with an odd sagittal frenulum on each galea +and an outer lattice-mantle, armed with ten styles (one odd and four paired +styles on each valve). + +The genus _Coelodecas_ is closely allied to _Coelographis_, but differs +from it in the development of a new pair of styles on each valve. These are +placed between the odd nasal and the paired tergal styles, are usually +directed laterally, parallel to the frontal axis of the body, and may +therefore be called frontal or lateral styles. The total number of coronal +styles is therefore ten. + + +1. _Coelodecas sagittaria_, n. sp. (Pl. 126, figs. 2_a_, 2_b_). + +Shell-mantle one and a half times as long as broad; its frontal perimeter +pentagonal, with a deep median incision at the base; the two oral sides of +the pentagon twice as long as the two lateral sides, and one and a half +times as long as the base. Sagittal perimeter ovate; equatorial perimeter +subcircular. Nasal odd style of each valve with fourteen to sixteen pairs +of branches, one and a half times as long as the paired frontal styles +(each with eight to nine pairs), and twice as long as the paired tergal +styles (each with four to six pairs of branches). Terminal coronets (on the +free distal ends of the styles) richly branched, each with thirty to forty +thorny fingers, which bear a conical point with recurved teeth, like an +arrow. + +_Dimensions._--Length of the shell 3.2, breadth 2.1. + +_Habitat._--Tropical Atlantic, Station 347, depth 2250 fathoms. + + +2. _Coelodecas decastyla_, n. sp. + +Shell-mantle one and a third times as long as broad; its frontal perimeter +pentagonal, with a slight incision on the base; the two oral sides of the +pentagon as long as the base, and one and a {1756}half times as long as the +two lateral sides. Nasal odd style of each valve with ten to twelve pairs +of branches, about twice as long as the four paired frontal and tergal +styles, each of which bears five or six pairs. Terminal coronets three +times forked, each with eight straight, spinulate, slightly divergent +fingers, shaped like a human finger. + +_Dimensions._--Length of the shell 3.6, breadth 2.7. + +_Habitat._--Central Pacific, Station 272, depth 2600 fathoms. + + +3. _Coelodecas pentagona_, n. sp. + +Shell-mantle about as long as broad; its frontal perimeter nearly regular +pentagonal, with five equal sides. Nasal odd style of each valve with six +to eight pairs of branches scarcely longer than the four paired frontal and +tergal styles, each of which is provided with four to six pairs. Terminal +coronets irregularly branched, each with twelve to sixteen slender curved +fingers, which bear at the distal end a spinulate knob. + +_Dimensions._--Length of the shell 2.6, breadth 2.4. + +_Habitat._--South Atlantic, Station 332, depth 2200 fathoms. + + + +Genus 737. _Coelostylus_,[353] n. gen. + +_Definition._--#Coelographida# with an odd sagittal frenulum on each galea +and an outer lattice-mantle, armed with twelve styles (two odd and four +paired styles on each valve). + +The genus _Coelostylus_ is characterised by the possession of twelve +coronal styles; it is closely allied to _Coelospathis_, and differs from +this in the development of a new pair of styles on each valve. These are +placed between the odd nasal and the odd sagittal style of each valve, they +are directed forwards, and may therefore be called "pectoral styles." + + +1. _Coelostylus bisenarius_, n. sp. (Pl. 126, fig. 3_a_, 3_b_). + +Shell-mantle one and a third times as long as broad; its frontal perimeter +pentagonal, with a deep median incision at the base; the two oral sides of +the pentagon about as long as the basal odd side, and half as long as the +two lateral sides. Sagittal perimeter (fig. 3_a_) octagonal; the three +paired lateral sides of the bilateral octagon about equal, and somewhat +shorter than the basal and oral odd sides. Equatorial perimeter rounded +square. Nasal odd style of each valve with twelve alternate-cruciate pairs +of lateral branches, about twice as long as the two paired pectoral styles +(each with four pairs), and the odd sagittal style (with six pairs); the +two paired tergal styles bear eight pairs and are longer than the latter, +shorter than the nasal style. All styles are more or less curved, +divergent, and at the distal end four times forked, bearing a terminal +coronet with sixteen spinulate fingers (fig. 3_b_). + +_Dimensions._--Length of the shell 4.2, breadth 3.2. + +_Habitat._--Indian Ocean (Madagascar), Rabbe, surface. + + +{1757}2. _Coelostylus flabellatus_, n. sp. + +Shell-mantle one and a half times as long as broad, very similar to that of +the preceding species. It differs from this mainly in the peculiar form of +the twenty-four terminal coronets, which are flabellate and very similar to +the terminal branches of _Coelodendrum flabellatum_ (Pl. 121, figs. 5, 6). +I formerly supposed, therefore, that both forms belonged to one and the +same species. But though I had no complete specimens of the two species, I +was afterwards led to the opinion that one and the same peculiar form of +terminal branches is here produced by adaptation to similar conditions in +two very different genera. Each coronet is a flat flabellum, placed in a +meridian plane, and composed of eight pairs of spinulate branches as +figured, _loc. cit._, in figs. 5 and 6. The cap-shaped distal end of each +finger is armed with eight to twelve recurved teeth. + +_Dimensions._--Length of the shell 3.8, breadth 2.6. + +_Habitat._--North Pacific, Station 252, surface. + + + +Genus 738. _Coeloplegma_,[354] n. gen. + +_Definition._--#Coelographida# with an odd frenulum on each galea and an +outer lattice-mantle, armed with fourteen styles (one odd and six paired +styles on each valve). + +The genus _Coeloplegma_, distinguished by the possession of fourteen +coronal styles, is closely allied to _Coelodecas_, but differs from it in +the development of a new pair of styles on each valve. These are placed +between the odd nasal and the paired frontal styles, are directed forwards, +and may therefore be called pectoral styles, corresponding to those of +_Coelostylus_. + + +1. _Coeloplegma murrayanum_, n. sp. (Pl. 127, figs. 1-13.). + +Shell-mantle about as long as broad, its frontal perimeter subcircular, or +slightly pentagonal, with five convex sides, its sagittal perimeter also +nearly circular. Odd nasal style with six to eight, the paired pectoral +styles with two or three, lateral styles with three to five, and tergal +styles with six to nine pairs of branches. The central capsule constantly +contains masses of crystals (figs. 4-7). Terminal coronets (on the free +distal ends of the styles) three times furcate, each with eight simple and +short fingers. This interesting species, discovered by Dr. John Murray in +August 1882, during the expedition of H.M.S. "Triton," in great numbers in +the Gulf Stream, off the Faeroee Channel, is very variable and connected by +numerous transitional forms with the following closely allied species. +(Compare the following note.) + +_Dimensions._--Length of the shell 1.6 to 2.2, breadth 1.5 to 2.1. + +_Habitat._--North Atlantic, Gulf Stream, off the Faeroee Channel, in depths +between 40 and 200 fathoms, John Murray. + + +{1758}2. _Coeloplegma tritonis_, n. sp. (Pl. 127, figs. 2-13). + +Shell-mantle one and a quarter times as long as broad, its frontal +perimeter heptagonal, with seven concave sides (fig. 2), its sagittal +perimeter ovate, its zonal perimeter nearly square (fig. 3). Odd nasal +style with twelve to fourteen, the paired pectoral styles with three to +four, lateral styles with six to eight, and tergal styles with eight to ten +pairs of branches. Coronets three times forked, each with eight terminal +branches, bearing a small spinulate knob. This remarkable species, in +external appearance very different from the preceding, is connected +immediately with it by numerous transitional varieties; both species +represent the opposite terminal poles of a long series of "Darwinian +metamorphic forms." If only the two specimens, figured in Pl. 127, figs. 1 +and 2, were known, every one would distinguish them as two widely different +species. But the careful comparison of numerous intermediate forms +demonstrates that there is no "missing link" in this long and remarkable +chain. The careful comparative study of these very variable and most highly +developed Coelographida may be regarded as a strong argument for the theory +of descent, and explains the true "origin of species." + +_Dimensions._--Length of the shell 1.8 to 2.5, breadth 1.5 to 2.1. + +_Habitat._--North Atlantic, Gulf Stream, off the Faeroee Channel, in depths +between 40 and 200 fathoms, John Murray. + + +3. _Coeloplegma tetradecastylum_, n. sp. + +Shell-mantle one and a third times as long as broad, its frontal perimeter +heptagonal, with seven concave sides. Similar to the preceding species, +differs from it mainly in the prolonged nasal style, which bears sixteen to +eighteen pairs of branches, and is about three times as long as each of the +six paired styles, each of which bears five to six pairs of branches. +Coronets three times forked, each with eight terminal branches, armed with +scattered spines, and bearing a knob with three recurved hooks. + +_Dimensions._--Length of the shell 3.2, breadth 2.4. + +_Habitat._--Tropical Atlantic, Stations 335 to 342, surface. + + +4. _Coeloplegma atlanticum_, n. sp. + +Shell-mantle one and a half times as long as broad, its frontal perimeter +ovate. Similar to _Coeloplegma murrayanum_ (Pl. 127, fig. 1), differs from +it in the different length of the styles; the nasal odd style (with +eighteen to twenty pairs of branches) is about twice as long as the lateral +styles (with ten to twelve pairs), and three times as long as the pectoral +and tergal styles (with six to eight pairs). Coronets four times forked, +each with sixteen terminal branches, armed with recurved spines, and +bearing a cross of four curved hooks. + +_Dimensions._--Length of the shell 2.5, breadth 1.7. + +_Habitat._--South Atlantic, Station 318, depth 2040 fathoms. + + + +{1759}Genus 739. _Coelagalma_,[355] n. gen. + +_Definition._--#Coelographida# with an odd sagittal frenulum on each galea +and an outer lattice-mantle, armed with sixteen styles (two odd and six +paired styles on each valve). + +The genus _Coelagalma_ represents the highest degree of development among +the Coelographida, and exhibits the maximum number of coronal styles in +this family, viz., sixteen (eight on each valve). Two of these are odd (as +in _Coelospathis_ and _Coelostylus_), viz., the longitudinal anterior nasal +style, and the horizontal sagittal style. The six others are paired (as in +_Coeloplegma_), viz., two anterior or pectoral, two lateral or frontal, and +two posterior or tergal styles. Since _Coelagalma_ in this highest +developed armature exceeds all the other Coeloplegmida, and exhibits at the +same time the utmost complexity in structural detail, it may be regarded as +one of the most perfect forms not among the PHAEODARIA only, but among all +Radiolaria. + + +1. _Coelagalma mirabile_, n. sp. (Pl. 126, figs. 4, 4_a_). + +Shell-mantle one and a half times as long as broad, its frontal perimeter +(fig. 4_a_) heptagonal, with seven concave sides, its sagittal perimeter +octagonal, its equatorial perimeter hexagonal (fig. 4_b_), the corners of +the polygons are marked by the sixteen prominent styles. Nasal odd style +longer; and sagittal odd style shorter, than the six paired styles of each +valve; the two pectoral styles are directed forwards, the two lateral +styles are nearly opposed in the horizontal frontal diameter, while the two +shorter tergal styles are directed backwards. The terminal coronets (at the +distal ends of the sixteen styles) are four times forked, with sixteen +equal spinulate fingers, each finger at the distal end with eight recurved +teeth. The entire surface of the bivalved latticed mantle is densely +studded with hundreds of most elegant anchor-pencils, so that the external +appearance of this beautiful species becomes one of the most wonderful +among Radiolaria. + +_Dimensions._--Length of the shell 5.4, breadth 3.6. + +_Habitat._--Central area of the Pacific, Station 271, depth 2425 fathoms. + + + + +{1760}NOTE ON THE DIMENSIONS AND MEASUREMENTS OF THE DESCRIBED SPECIES OF +RADIOLARIA. + + +All the dimensions of the species of Radiolaria described in the present +work are given in millimetres. In the majority of the species the +dimensions of only a single observed specimen have been measured by the +micrometer, and usually only the most important proportions have been +recorded. But since the outlines of nearly all the species figured (with +very few exceptions) have been drawn by the camera lucida, and therefore +usually are almost perfectly exact, and since the excellent artist, Mr. +Adolph Giltsch, has executed the lithographic plates with the greatest +accuracy, having examined the objects themselves under the microscope, it +is very easy to determine the dimensions of all the separate parts by +comparative measurement. In very many of the species described (perhaps +nine hundred or a thousand) several specimens of each species (usually +three or four) have been measured comparatively, and the dimensions +recorded are taken as averages. A very important contribution to the +general conception of the proportions, and especially to the important +question of the constancy of the dimensions, has been given by my honoured +friend Dr. Reinhold Teuscher of Jena. This excellent observer, to whom I am +indebted for much and important co-operation in my Radiolarian work, has +instituted at my request a long series of measurements, with the view of +comparing the dimensions (of the entire skeleton as well as of its +individual parts) in numerous (usually twenty or thirty) specimens of one +and the same species. About three hundred species of very different groups +(mainly #Sphaeroidea#, #Discoidea#, #Spyroidea#, and #Cyrtoidea#) have been +measured in this manner, and the general survey of the results obtained +(about eight thousand measurements were recorded) has enabled me to form a +good opinion of the constancy and variability of the dimensions in the +individual species. The general result is, that they are not absolutely +constant in any given case, but that each species (of which many specimens +have been carefully compared) exhibits a certain degree of variability in +all its proportions. The general meaning of "species," therefore, is in the +unicellular Radiolaria the same as in all other organisms, and its +development follows the same laws as are so accurately explained by Charles +Darwin in his Origin of Species. + + + + +ADDENDA. + + + I. _List of Twenty-two Deep-Sea Radiolarians from the Banda Sea._ + +P. Harting (L. N. 18) published in 1863 the description of 14 SPUMELLARIA +and 8 NASSELLARIA, taken in depths between 900 and 4000 fathoms, in the +Banda Sea. The figures of them are, however, for the most part not complete +enough. The names are the following:-- + + + I. SPUMELLARIA. + + 1. _Haliomma nitidum_, figs. 13, 14 = _Heliodiscus_? + 2. _Haliomma gracile_, fig. 15 = _Acanthosphaera_? + 3. _Haliomma lens_, fig. 16 = _Stylodiscus_? + 4. _Haliomma pyriforme_, fig. 17 = _Cenellipsis_? + 5. _Haliomma scutum_, fig. 18 = _Botryocella_? + 6. _Haliomma polyacanthum_, fig. 40 = _Druppocarpus_? + 7. _Haliomma inerme_, fig. 41 = _Thecosphaera_? + 8. _Haliomma oblongum_, fig. 42 = _Druppula_? + 9. _Haliomma amphiaspis_, fig. 43 = _Monozonium_? + 10. _Tetrapyle polyacantha_, fig. 44 = _Larcarium_? + 11. _Flustrella cyclica_, fig. 19 = _Porodiscus_. + 12. _Flustrella micromma_, fig. 47 = _Porodiscus_. + 13. _Rhopalastrum bandaicum_, fig. 45 = _Dictyastrum_. + 14. _Lithocyclia reticulata_, fig. 20 = _Spongodiscus_? + + II. NASSELLARIA. + + 15. _Lithocircus annulus_, fig. 50 = _Lithocircus_. + 16. _Acanthodesmia arcuata_, fig. 25 = _Zygostephanus_. + 17. _Acanthodesmia inermis_, fig. 26 = _Dictyospyris_? + 18. _Cladospyris moluccana_, fig. 48 = _Cyphonium_? + 19. _Podocyrtis brevipes_, fig. 24 = _Podocyrtis_. + 20. _Podocyrtis micracantha_, fig. 49 = _Podocampe_? + 21. _Lithocampe corbula_, fig. 21 = _Lithomitra_. + 22. _Lithocampe sinuosa_, fig. 22 = _Lithocampe_? + + + II. _List of Fossil Radiolaria (probably Jurassic) found in the "Diaspri + della Toscana," and described in 1880 by Dante Pantanelli_ (L. N. 36). + (_Compare_ s 243, _Note_ B, p. clxviii). + +The figures are too small and too incomplete for certain determination. + + I. SPUMELLARIA. + + 1. _Ethmosphaera minuta_. + 2. _Ethmosphaera vulgaris_. + 3. _Ethmosphaera siphonophora_. + 4. _Heliosphaera echinoidites_. + 5. _Rhaphidococcus lusianensis_. + 6. _Heliodiscus simplex_. + 7. _Histiastrum lusianense_. + 8. _Trematodiscus soritoides_. + 9. _Euchitonia muellerites_. + 10. _Euchitonia amoena_. + 11. _Euchitonia clathrata_. + 12. _Euchitonia crevolensis_. + 13. _Euchitonia grandis_. + 14. _Euchitonia dubia_. + + II. NASSELLARIA. + + 15. _Lithocircus haeckelii_. + 16. _Lithocircus truncatus_. + 17. _Lithocircus rhombus_. + 18. _Cornutella pseudoprofunda_. + 19. _Cornutella pseudoclathrata_. + 20. _Lithopera ovata_. + 21. _Lithopera elongata_. + 22. _Polystichia ehrenbergii_. + 23. _Polystichia haeckelii_. + 24. _Polystichia muelleri_. + 25. _Urocyrtis emmae_. + 26. _Urocyrtis amaliae_. + 27. _Urocyrtis stephanii_. + 28. _Adelocyrtis cometa_. + 29. _Adelocyrtis pala_. + 30. _Adelocyrtis spinosa_. + + + + +ERRATA. + + + Page 23, line 3 from top, _add_ "Compare also _Myxobrachia cienkowski_, + Wagner, 1872, L. N. 23." + + Page 40, bottom line, _add_ "The two following species are incompletely + known:--_Sphaerozoum orientale_, Dana, 1863, _Ann. and Mag. Nat. Hist._, + vol. xii. p. 54. _Sphaerozoum sanderi_, Doenitz, 1871, L. N. 60, p. 71." + + Page 65, line 15 from top, _add_ "_Cenosphaera radiata_, Zittel, 1876 (L. + N. 29, p. 84, Taf. ii. figs. 7, 8), a fossil Cretaceous species, is + closely allied to _Cenosphaera compacta_." + + Page 84, line 17 from top, _add_ "_Caryosphaera polysphaerica_, + Buetschli, 1882 (L. N. 41, Taf. xxiii. fig. 12) is probably a + _Cromyosphaera_ (fossil in Barbados)." + + Page 95, line 11 from top, _add_ "_Dermatosphaera_, Ehrenberg, is a + _Collosphaera_ with small pores (compare L. N. 16, p. 533)." + + Page 97, line 8 from foot, _for_ "xxiv." _read_ "xxxiv." + + Page 122, line 14 from foot, _for_ "_Spongolonche_" _read_ + "_Spongolonchis_." + + Page 149, lines 1, 4, 6 and 12 from top, _for_ "_Spongolonche_" _read_ + "_Spongolonchis_." + + Page 149, line 2 from foot, _for_ "_Spongolonche_" _read_ + "_Spongolonchis_ ([Greek: spongos], [Greek: lonchis])." + + Page 172, line 4 from foot, _add_ Synonym "? _Haliphormis hexacantha_, + Ehrenberg, 1872, L. N. 24, Taf. x. fig. 6." + + Page 216, line 11 from foot, _add_ "Taf. xiii." + + Page 308, line 4 from top, _add_ "Compare _Haliomma oblongum_, Harting, + 1863, L. N. 18, p. 15, pl. 2, fig. 42." + + Page 326, line 14 from foot, _for_ "1872" _read_ "1875." + + Page 461, line 12 from foot, _delete_ "H." + + Page 463, line 10 from top, _add_ "Indian Ocean, Cocos Islands, Rabbe." + + Page 492, bottom line, _add_ "_Porodiscus haeckelii_ = _Trematodiscus + haeckelii_, Buetschli, 1882, L. N. 41, Taf. xxiv. figs. 5_a_, 5_b_." + + Page 509, bottom line, _add_ "_Stylodictya haeckelii_, Zittel, 1876, L. + N. 29, p. 85, Taf. ii. fig. 9, is a fossil Cretaceous species, related to + _Stylodictya multispina_." + + Page 534, line 11 from foot, _add_ "Indian Ocean, Cocos Islands (Rabbe). + Also in the Central Pacific, Station 267." + + Page 584, line 12 from top, _for_ "1872" _read_ "1875." + + Page 586, line 7 from foot, _add_ "_Spongotrochus ehrenbergii_, + Buetschli, 1882, L. N. 41, Taf. xxvi. figs. 1_a_, 1_b_." + + Page 633, bottom line, _add_ "_Monozonium hartingii_ = _Haliomma + amphiaspis_, Harting, 1863 (L. N. 18, p. 15, pl. 2, fig. 43)." + + Page 763, line 8 from top, _add_ "Pl. 132, fig. 11." + + Page 784, line 16 from top, _for_ "vi." _read_ "xvi." + + Page 802, line 14 from bottom, _after_ "11_a_" _insert_ "11_c_." + + Page 839, line 13 from top, _for_ "95" _read_ "135." + + Page 841, line 8 from foot, _after_ "figs." _insert_ "2." + + Page 842, line 13 from top, _add_ "_Haliomma ligurinum_, J. Mueller (= + _Haliommatidium ligurinum_, Haeckel, L. N. 16, p. 423) seems to be + closely allied to the preceding." + + Page 889, line 6 from top, _add_ "_Cricoidea_, Buetschli, 1882 (L. N. 40, + p. 537) = NASSELLARIA." + + Page 951, line 9 from foot, _add_ "Fossil in Barbados." + + Page 952, line 2 from foot, _add_ "Fossil in Barbados." + + Page 966, line 10 from top, _add_ "Fossil in Barbados." + + Page 981, line 19 from top, _add_ "Fossil in Barbados." + + Page 1037, line 8 from top, _add_ "Pl. 85, fig. 2." + + Page 1081, line 12 from foot, _add_ "Pl. 95, fig. 15." + + Page 1158, line 10 from foot, _for_ "516. _Cyrtophormis_" _read_ "516. + _Cystophormis_." + + Page 1165, lines 8, 11 and 15 from foot, _for "Cyrtophormis" read + "Cystophormis_." + + Page 1165, bottom line, _read_ "_Cystophormis_ = bladder-basket; [Greek: + kyste], [Greek: phormis]." + + Page 1166, lines 1, 7 and 13 from top, _for_ "_Cyrtophormis_" _read_ + "_Cystophormis_." + + Page 1250, line 7 from top, _for_ "_Dictyoprora_" _read_ "_Dictyoprona_." + + Page 1251, line 11 from top, _add_ "Pl. 62, fig. 3." + + Page 1356, line 9 from foot, _add_ "Pl. 68, fig. 14." + + Page 1384, line 2 from foot, _for_ "_Calocycloma_" _read_ + "_Calocyclura_." + + Page 1411, first line, _add_ "Pl. 68, fig. 15." + + Page 1560, line 2 from top, _add_ "_Dictyocha trigona_, Zittel, 1876 (L. + N. 29, p. 83, Taf. ii. fig. 6), is an interesting Cretaceous species, + perhaps a variety of _Dictyocha triommata_." + + Page 1615, line 6 from top, _insert_ "n. sp." _after_ "_scenophora_." + + Page 1653, line 7 from top, _add_ "John Murray, 1876, L. N. 27, pl. 24, + fig. 2." + + Page 1706, line 7 from foot, _add_ "John Murray, 1876, L. N. 27, pl. 24, + fig. 4." + + Page 1752, line 4 from bottom, _for_ "figs. 1_a_-1_d_" _read_ "figs. + 1_a_-1_c_." + + Page 1757, line 14 from bottom, _for_ "fig. 1" _read_ "figs. 1-13." + + Page 1759, line 14 from bottom _for_ "figs. 4_a_, 4_b_" read "figs. 4, + 4_a_." + + + + +INDEX. + + Synonyms are printed in _Italics_; names of Families, Orders, &c., in + CAPITALS. + + ACANTHARIA, 716. + Acanthochiasma, 739. + fusiforme, 739. + krohnii, 739. + rubescens, 739. + spirale, 739. + ACANTHOCHIASMIDA, 738. + Acanthocorallium, 1262. + Acanthocoronium, 1263. + Acanthocorys, 1261. + buetschlii, 1262. + dodecaster, 1264. + enneapodia, 1263. + furcata, 1264. + hexapodia, 1262. + macroceras, 1264. + macropodia, 1262. + polypodia, 1264. + pristipodia, 1262. + triloba, 1263. + umbellifera, 1263. + Acanthocorythium, 1264. + Acanthocyrtis, 1494. + Acanthocystis, 1461. + Acanthodesmia, 975. + _arcuata_, 1761. + ceratospyris, 976. + corona, 976. + _dumetum_, 930. + _hertwigii_, 983. + _inermis_, 1761. + muelleri, 976. + _polybrocha_, 930. + _prismatium_, 1010. + vinculata, 975. + ACANTHODESMIDA, 973. + Acantholithium, 753. + Acantholonche, 790. + amphipolaris, 790. + peripolaris, 791. + ACANTHOLONCHIDA, 781. + ACANTHOMETRA, 725. + _Acanthometra_, 742. + _alata_, 761. + _anomale_, 789. + _arachnoides_, 910. + _belonoides_, 783. + _brevispina_, 745. + _bulbosa_, 743. + _cataphracta_, 810. + _claparedei_, 751. + _complanata_, 786. + _compressa_, 747. + _costata_, 812. + _cruciata_, 754. + _cuspidata_, 752. + _dichotoma_, 747. + _dolichoscia_, 743. + _echinoides_, 751. + _elastica_, 742. + _elongata_, 785. + _forceps_, 770. + _fragilis_, 750. + _furcata_, 747. + _fusca_, 743. + _hastata_, 770. + _hemicompressa_, 748. + _heteracantha_, 784. + _lanceolata_, 746. + _messanensis_, 786. + _mucronata_, 756. + _muelleri_, 750. + _multispina_, 752. + _ovata_, 785. + _pallida_, 770. + _pectinata_, 757. + _pellucida_, 744. + _purpurascens_, 769. + _quadridentata_, 758. + _quadrifolia_, 752. + _serrata_, 757. + _sicula_, 744. + _spinulosa_, 759. + _tenuis_, 784. + _tetracopa_, 749. + _tetraptera_, 787. + _wageneri_, 744. + ACANTHOMETREA, 716. + Acanthometrella, 742. + ACANTHOMETRIDA, 725. + Acanthometron, 742. + bifidum, 745. + bulbiferum, 745. + bulbosum, 743. + catervatum, 745. + conicum, 743. + cylindricum, 743. + dolichoscion, 743. + elasticum, 742. + fuscum, 743. + pellucidum, 744. + siculum, 744. + wageneri, 744. + Acanthonarium, 749. + Acanthonia, 751. + claparedei, 751. + concava, 750. + convexa, 750. + cuspidata, 752. + denticulata, 750. + diplopyramis, 752. + echinoides, 751. + fragilis, 750. + muelleri, 750. + multispina, 752. + prismatica, 749. + quadrangula, 751. + quadrifolia, 752. + serrulata, 753. + stellata, 753. + tetracopa, 749. + ACANTHONIDA, 740. + Acanthonidium, 751. + ACANTHOPHRACTA, 791. + ACANTHOPHRACTIDA, 791. + Acanthosphaera, 209. + acanthica, 215. + acufera, 211. + angulata, 216. + antarctica, 214. + arctica, 214. + brevispina, 215. + capillaris, 214. + castanea, 211. + clavata, 212. + compacta, 213. + conifera, 216. + _coronata_, 219. + dentata, 211. + echinoides, 214. + _elliptica_, 350. + enneacantha, 213. + florida, 213. + flosculenta, 211. + fortispina, 212. + gibbosa, 216. + haliphormis, 215. + insignis, 212. + longispina, 215. + macropora, 210. + marginata, 212. + maxima, 216. + micropora, 210. + mucronata, 212. + octahedralis, 213. + _pectinata_, 218. + reticulata, 217. + _setosa_, 174. + simplex, 216. + tenuis, 210. + tenuissima, 210. + _zonaster_, 281. + ACANTHOSTAURIDA, 768. + Acanthostaurus, 769. + aequatorialis, 769. + bipennis, 769. + conacanthus, 769. + cruciatus, 771. + forceps, 770. + hastatus, 770. + pallidus, 770. + purpurascens, 769. + Acontasparium, 829. + Acontaspidium, 829. + Acontaspis, 829. + capillata, 830. + furcata, 829. + hastata, 829. + lanceolata, 829. + Acostaurus, 769. + Acrobotrys, 1114. + acuminata, 1115. + aquaria, 1114. + auriculata, 1115. + disolenia, 1114. + monosolenia, 1114. + pentasolenia, 1115. + tetrasolenia, 1115. + trisolenia, 1115. + Acrocalpis, 1168. + _virginica_, 1169. + Acrocorona, 1176. + Acrocoronis, 977. + Acrocubus, 992. + amphistylus, 993. + amphithectus, 994. + arcuatus, 993. + brachiatus, 993. + cortina, 994. + lasanum, 994. + octopylus, 993. + tesseralis, 993. + tetrapodius, 994. + Acromelissa, 1203. + Acropyramis, 1159. + Acrosphaera, 99. + collina, 101. + echinoides, 100. + erinacea, 100. + inflata, 101. + setosa, 100. + spinosa, 100. + ACROSPHAERIDA, 94. + ACROSPYRIDA, 1085. + Acrospyris, 1085. + clathrocanium, 1085. + dictyophimus, 1085. + fragilis, 1086. + macrocephala, 1085. + pyramidalis, 1086. + Actidiscus, 15. + _discoides_, 15. + _lenticularis_, 15. + _phacoides_, 15. + Actilarcus, 16. + _larcoides_, 16. + Actinastrum, 733. + legitimum, 733. + pentazonium, 733. + Actinelarium, 730. + ACTINELIDA, 728. + Actinelidium, 730. + Actinelius, 730. + pallidus, 731. + polyacanthus, 731. + primordialis, 730. + protogenes, 730. + purpureus, 730. + Actinelonium, 731. + Actinomma, 251. + _aculeatum_, 258. + anthomma, 252. + arcadophorum, 255. + _asteracanthion_, 196. + capillaceum, 255. + castanomma, 253. + crenatum, 314. + _daturaeforme_, 164. + denticulatum, 254. + dodecomma, 256. + drymodes, 198. + entactinia, 253. + facetum, 252. + _fenestratum_, 315. + giganteum, 256. + _hexactis_, 192. + hexagonium, 252. + hirsutum, 251. + _inerme_, 80. + japonicum, 253. + _medusa_, 80. + pachycapsa, 256. + pachyderma, 254. + schwageri, 256. + _sphaerechinus_, 258. + spinigerum, 254. + _tetracanthum_, 164. + trinacrium, 254. + _triplex_, 314. + ACTINOMMATIDA, 251. + Actinommida, 251. + Actinopyramis, 1256. + Actiprunum, 14. + _ellipsoides_, 14. + _prunoideum_, 14. + ACTIPYLEA, 716. + Actissa, 12. + discoides, 15. + ellipsoides, 14. + larcoides, 16. + lenticularis, 15. + phacoides, 13. + primordialis, 13. + princeps, 13. + prototypus, 13. + prunoides, 14. + radiata, 14. + ADELACANTHA, 717. + Adelocyrtis, 1762. + cometa, 1762. + pala, 1762. + spinosa, 1762. + Aegospyris, 1053. + aegoceras, 1054. + aequispina, 1053. + caprina, 1054. + longibarba, 1054. + octospina, 1053. + Alacorys, 1370. + aculeata, 1373. + bismarckii, 1372. + carcinus, 1375. + dodecantha, 1375. + enneacantha, 1374. + friderici, 1372. + gigas, 1374. + guilelmi, 1372. + hexacantha, 1373. + hexapleura, 1373. + lutheri, 1370. + octacantha, 1374. + ornata, 1375. + pentacantha, 1371. + polyacantha, 1375. + tetracantha, 1371. + Amphiactura, 470. + _diploconus_, 470. + amphibrachia, 470. + Amphibelithium, 790. + Amphibelone, 788. + aciculata, 788. + anomala, 789. + clavaria, 790. + cultellata, 789. + pyramidata, 789. + Amphibelonium, 788. + Amphibrachium, 516. + amphilonche, 517. + armatum, 518. + capitatum, 518. + clavula, 518. + dilatatum, 517. + indicum, 518. + lanceolatum, 517. + murrayanum, 523. + sponguroides, 517. + _Amphicentria_, 614. + _salpa_, 614. + Amphicraspedum, 523. + maclaganium, 523. + murrayanum, 523. + wyvilleanum, 523. + Amphicyclia, 463. + amphistylia, 464. + chronometra, 463. + pachydiscus, 464. + AMPHILITHIDA, 781. + Amphilithium, 787. + Amphiloncharium, 783. + Amphilonche, 783. + acufera, 788. + _anomala_, 789. + belonoides, 783. + complanata, 786. + concreta, 787. + conica, 785. + denticulata, 784. + diodon, 783. + elongata, 785. + heteracantha, 384. + hydrotomica, 786. + lanceolata, 783. + lancetta, 786. + messanensis, 786. + ovata, 785. + tenuis, 784. + tetraptera, 787. + violina, 787. + AMPHILONCHIDA, 781. + Amphilonchidium, 785. + Amphiplecta, 1223. + acrostoma, 1223. + amphistoma, 1223. + callistoma, 1224. + Amphipyle, 641. + aceros, 641. + amphiceros, 691. + amphiptera, 642. + callizona, 644. + cladoceros, 643. + decaceros, 643. + hexaceros, 642. + octoceros, 643. + platyptera, 641. + stauroceros, 642. + stenoptera, 641. + tetraceros, 642. + Amphipylonium, 656. + octoceras, 657. + semilunare, 656. + spinosissimum, 657. + tetraceros, 657. + Amphirrhopalum, 521. + amphidicranum, 521. + bigeminum, 522. + echinatum, 522. + ximorphum, 521. + ypsilon, 532. + Amphisphaera, 142. + apollo, 143. + cronos, 144. + jupiter, 143. + mars, 144. + mercurius, 143. + neptunus, 142. + pluto, 144. + uranus, 143. + Amphispyridium, 1096. + Amphispyris, 1095. + costata, 1097. + quadrigemina, 1096. + reticulata, 1096. + sternalis, 1096. + subquadrata, 1097. + thorax, 1096. + toxarium, 1097. + Amphispyrium, 1095. + AMPHISTYLIDA, 142. + Amphistylus, 145. + clio, 145. + _giganteus_, 329. + glyptodon, 145. + hippocampus, 145. + _neptunus_, 328. + AMPHITHOLIDA, 663. + Amphitholonium, 668. + acanthonium, 669. + octostylonium, 669. + tricolonium, 669. + Amphitholus, 666. + acanthometra, 667. + armatus, 668. + artidium, 666. + artiscus, 666. + dodecanthus, 667. + octacanthus, 667. + panicium, 668. + polyacanthus, 668. + Amphymenium, 519. + amphistylium, 520. + fusiforme, 521. + monstrosum, 520. + naviculare, 519. + pupula, 519. + zygartus, 520. + ANDROSPYRIDA, 1090. + Androspyris, 1092. + anthropiscus, 1093. + aptenodytes, 1093. + homunculus, 1092. + pithecus, 1093. + Anthocorys, 1456. + _campanula_, 1456. + Anthocyrtarium, 1272. + Anthocyrtella, 1269. + ANTHOCYRTIDA, 1241. + Anthocyrtidium, 1278. + cineraria, 1278. + ligularia, 1278. + matricaria, 1279. + Anthocyrtis, 1269. + butomus, 1270. + _collaris_, 1273. + _cothurnata_, 1353. + _ehrenbergii_, 1277. + enneaphylla, 1271. + _ficus_, 1277. + _flosculus_, 1277. + furcata, 1269. + grossularia, 1271. + hispida, 1275. + lauranthus, 1271 + _leptostyla_, 1275. + mespilus, 1269. + ophirensis, 1270. + ovata, 1272. + _serrulata_, 1268. + _sethoconus_, 1296. + _setosa_, 1276. + subglobosa, 1271. + ventricosa, 1270. + _zanguebarica_, 1277. + Anthocyrtissa, 1270. + Anthocyrtium, 1272. + adonis, 1273. + anemone, 1274. + anthemis, 1273. + campanula, 1274. + centaurea, 1273. + chrysanthemum, 1272. + collare, 1273. + doronicum, 1276. + ehrenbergii, 1277. + ficus, 1277. + flosculus, 1277. + hispidum, 1275. + leptostylum, 1275. + pyrum, 1276. + reticulatum, 1274. + setosum, 1276. + turris, 1275. + zanguebaricum, 1277. + Anthocyrtoma, 1268. + alterna, 1268. + serrulata, 1268. + Anthocyrtonium, 1274. + Anthocyrtura, 1271. + Anthocyrturium, 1276. + _Anthomma_, 76. + _nodusum_, 76. + Anthospyris, 1064. + aculeata, 1065. + arachnoides, 1065. + diaboliscus, 1065. + doronicum, 1065. + mammillata, 1064. + spathulata, 1065. + tragopogon, 1066. + Apocubus, 992. + Arachnocalpis, 1172. + ellipsoides, 1172. + sphaeroides, 1173. + Arachnocorallium, 1265. + Arachnocoronium, 1266. + Arachnocorys, 1265. + arachnodiscus, 1267. + araneosa, 1266. + circumtexta, 1266. + discoides, 1265. + enneaptera, 1266. + hexaptera, 1265. + polyptera, 1267. + trifida, 1267. + _umbellifera_, 1263. + Arachnocorythium, 1267. + Arachnopegma, 267. + increscens, 267. + longispinum, 267. + verticillatum, 267. + Arachnopila, 266. + hexagonella, 266. + polygonella, 266 + Arachnopilium, 1327. + _clathrocanium_, 1327. + Arachnosphaera, 268. + dolichacantha, 269. + increscens, 269. + myriacantha, 268. + oligacantha, 268. + tenuissima, 269. + velaris, 269. + ARACHNOSPHAERIDA, 265. + Archibursa, 1157. + tripodiscus, 1157. + Archicapsa, 1191. + nonaforis, 1192. + quadriforis, 1192. + triforis, 1191. + ARCHICAPSIDA, 1189. + Archicircus, 940. + duodenus, 942. + ellipsis, 941. + hertwigii, 942. + hexacanthus, 942. + monopylus, 941. + monostephus, 941. + ovalis, 941. + primordialis, 942. + princeps, 940. + quadratus, 941. + rhombus, 942. + sexangularis, 943. + triglyphus, 943. + ARCHICORIDA, 1180. + Archicorys, 1184. + ampulla, 1184. + galea, 1184. + globosa, 1185. + microstoma, 1185. + ovata, 1185. + ARCHIDISCIDA, 485. + Archidiscus, 486. + dioniscus, 486. + dithalamus, 486. + hexathalamus, 489. + hexoniscus, 488. + octoniscus, 489. + pentoniscus, 488. + polythalamus, 489. + pylonsicus, 488. + stauroniscus, 487. + tetrathalamus, 487. + tetroniscus, 487. + trioniscus, 487. + trithalamus, 487. + Archipera, 1155. + bicornis, 1156. + cortiniscus, 1155. + multicornis, 1156. + pentacantha, 1155. + quadricornis, 1156. + tricornis, 1156. + ARCHIPERIDA, 1146. + Archiperidium, 1154. + Archiphaena, 1177. + corona, 1178. + gorgospyris, 1178. + stephanoma, 1178. + ARCHIPHAENIDA, 1173. + ARCHIPHORMIDA, 1159. + Archiphormis, 1167. + campanulata, 1165. + cancellata, 1167. + urceolata, 1168. + ARCHIPILIDA, 1135. + Archipilium, 1139. + cyrtopterum, 1140. + orthopterum, 1139. + sigmopterum, 1139. + Archiscenium, 1150. + callimitra, 1151. + clathrocorys, 1150. + cyclopterum, 1151. + quadrispinum, 1150. + _tricolpium_, 1147. + tripterygium, 1151. + Archistephus, 941. + Artidium, 356. + ARTINIDA, 354. + Artiscium, 355. + Artiscus, 355. + elegans, 356. + facetus, 355. + hystrix, 356. + nodosus, 356. + panarius, 356. + paniculus, 355. + paniscus, 355. + Artocapsa, 1519. + armata, 1520. + elegans, 1520. + fusiformis, 1519. + infraculeata, 1519. + octocamera, 1520. + quadricamera, 1520. + spinosa, 1519. + ARTOCAPSIDA, 1467. + ARTOCORIDA, 1467. + Artocyrtis, 1490. + Artopera, 1452. + fusiformis, 1452. + loxia, 1452. + motacilla, 1452. + _thoracoptera_, 1450. + ARTOPERIDA, 1435. + Artophaena, 1463. + aerostatica, 1463. + hexalatractus, 1464. + hexapodiscus, 1464. + senaria, 1464. + ARTOPHAENIDA, 1453. + ARTOPHORMIDA, 1453. + Artophormis, 1458. + barbadensis, 1459. + costata, 1459. + horrida, 1458. + ARTOPILIDA, 1435. + Artopilium, 1439. + anomalum, 1442. + cornutella, 1441. + cyrtopterum, 1440. + elegans, 1440. + longicorne, 1440. + stichopterygium, 1442. + trifenestra, 1441. + trigonopterum, 1441. + Artostrobium, 1482. + Artostrobulus, 1481. + Artostrobus, 1481. + annulatus, 1481. + articulatus, 1482. + auritus, 1482. + biseriatus, 1482. + elegans, 1482. + _Aspidomma_, 847. + _hystrix_, 854. + _mucronatum_, 756. + Astractinium, 476. + Astractura, 476. + aristotelis, 476. + clavigera, 476. + democriti, 477. + hippocratis, 477. + ordinata, 476. + ASTRACTURIDA, 469. + Astracturium, 476. + Astrocapsa, 799. + coronata, 799. + quadrifida, 799. + stellata, 799. + tritonis, 799. + ASTROCAPSIDA, 797. + Astrocyclia, 466. + arachnia, 467. + heterocycla, 468. + rotula, 467. + solaster, 466. + stella, 467. + ASTROCYRTIDA, 1129. + ASTROLITHIDA, 726. + Astrolithium, 745. + _bifidum_, 745. + _bulbiferum_, 745. + _cruciatum_, 771. + _dicopum_, 748. + Astroloncharium, 756. + Astrolonche, 756. + bicruciata, 756. + mucronata, 756. + pectinata, 757. + pinnata, 757. + serrata, 757. + ASTROLONCHIDA, 740. + Astrolonchidium, 757. + ASTROLOPHIDA, 728. + Astrolophus, 732. + solaris, 732. + stellaris, 732. + _Astromma_, 475. + _aristotelis_, 476. + _entomocora_, 367. + _pentactis_, 479. + _pythagorae_, 471. + Astrophacus, 453. + apollinis, 455. + asteriscus, 453. + cingillum, 454. + phacodiscus, 454. + saturnus, 454. + solaris, 453. + trochiscus, 453. + Astrosestrum, 442. + acanthastrum, 443. + acraspedum, 443. + _caudatum_, 431. + echinastrum, 443. + ephyra, 442. + floscula, 444. + nauphanta, 442. + octacanthum, 442. + pelagia, 444. + Astrosphaera, 250. + hexagonalis, 250. + splendens, 250. + sideraea, 251. + stellata, 251. + ASTROSPHAERIDA, 206. + Astrostaurus, 436. + _magnificus_, 436. + Astrostylus, 431. + Atactodiscus, 497. + _irregularis_, 498. + Aulacantha, 1575. + cannulata, 1576. + clavata, 1576. + laevissima, 1576. + scolymantha, 1575. + spinosa, 1575. + tubulosa, 1575. + AULACANTHIDA, 1569. + AULACTINIDA, 1573. + Aulactinium, 1574. + actinastrum, 1574. + actinelium, 1574. + actinosphaerium, 1574. + Aularia, 1621. + ternaria, 1621. + trigonaria, 1621. + tubularia, 1621. + AULARIDA, 1620. + Aulastrum, 1635. + dendroceros, 1635. + dichoceros, 1635. + monoceros, 1635. + pentaceros, 1636. + polyceros, 1636. + tetraceros, 1636. + triceros, 1635. + trichoceros, 1636. + Aulatractus, 1632. + diploconus, 1632. + ellipsoides, 1633. + fusiformis, 1632. + fusulus, 1632. + Auloceraea, 1583. + Auloceratium, 1585. + Auloceros, 1583. + arborescens, 1585. + capreolus, 1584. + cervinus, 1584. + dicranaster, 1585. + elegans, 1584. + furcosus, 1583. + spathillaster, 1585. + trigeminus, 1584. + Aulodendron, 1588. + antarcticum, 1589. + atlanticum, 1589. + australe, 1589. + indicum, 1590. + pacificum, 1589. + Aulodictyum, 1637. + hydrodictyum, 1637. + Aulographantha, 1577. + Aulographella, 1579. + AULOGRAPHIDA, 1574. + Aulographidium, 1580. + Aulographis, 1577. + asteriscus, 1581. + ancorata, 1578. + bovicornis, 1577. + candelabrum, 1582. + cruciata, 1578. + dentata, 1582. + flammabunda, 1579. + flosculus, 1580. + furcula, 1580. + gemmascens, 1580. + hexancistra, 1581. + martagon, 1579. + pandora, 1577. + penicillata, 1578. + pistillum, 1579. + polyancistra, 1581. + pulvinata, 1582. + serrulata, 1582. + stellata, 1578. + taumorpha, 1577. + tetrancistra, 1581. + triaena, 1579. + triangulum, 1580. + triglochin, 1578. + tripentas, 1582. + verticillata, 1582. + Aulographonium, 1581. + Aulonia, 1633. + hexagonia, 1634. + metagonia, 1634. + pentagonia, 1634. + polygonia, 1634. + tetragonia, 1633. + AULONIDA, 1633. + Aulophacus, 1631. + amphidiscus, 1631. + lenticularis, 1631. + Auloplegma, 1630. + perplexum, 1630. + spongiosum, 1631. + Auloscena, 1628. + arboretum, 1629. + flammabunda, 1629. + gigantea, 1629. + mirabilis, 1628. + penicillus, 1629. + pyramidalis, 1628. + serrata, 1630. + spectabilis, 1628. + tentorium, 1628. + verticillus, 1629. + Aulospathessa, 1586. + Aulospathilla, 1587. + Aulospathis, 1586. + bifurca, 1586. + diodon, 1587. + furcata, 1588. + hexodon, 1588. + polymorpha, 1587. + quadrifurca, 1587. + tetrodon, 1588. + trifurca, 1586. + triodon, 1587. + variabilis, 1588. + Aulosphaera, 1622. + bifurca, 1626. + bisternaria, 1624. + coronata, 1626. + cruciata, 1624. + dendrophora, 1625. + diodon, 1623. + elegantissima, 1624. + flexuosa, 1622. + _gracilis_, 1609. + multifurca, 1626. + polyodon, 1623. + _pourtalesii_, 1624. + quadrifurca, 1626. + sceptrophora, 1625. + spathillata, 1624. + spathophora, 1625. + spinosa, 1627. + tetrodon, 1623. + trifurca, 1626. + trigonopa, 1622. + triodon, 1623. + undulata, 1627. + verticillata, 1624. + AULOSPHAERIDA, 1615. + Axellipsis, 293. + lobata, 293. + perforata, 293. + Axocorys, 1420. + macroceros, 1420. + Axodiscus, 490. + hexagonus, 490. + octogonus, 491. + spinosus, 491. + staurophorus, 490. + stylophorus, 490. + trigonus, 490. + triradiatus, 490. + Axoprunum, 298. + stauraxonium, 298. + + Bathropyramis, 1159. + acephala, 1159. + interrupta, 1160. + medusa, 1160. + quadrata, 1159. + ramosa, 1161. + spinosa, 1160. + trapezoides, 1160. + BELOIDEA, 28. + BELONASPIDA, 859. + Belonaspis, 863. + conifera, 864. + datura, 863. + furcata, 863. + lanceolata, 864. + multiforis, 864. + pandanus, 863. + Belonostaurus, 771. + bicuspis, 772. + quadratus, 771. + Belonozoum, 39. + atlanticum, 40. + bacillosum, 39. + italicum, 40. + spinulosum, 40. + BOTRIDA, 1103. + BOTRYIDA, 1103. + Botryocampe, 1122. + camerata, 1124. + galea, 1123. + hexathalamia, 1125. + inflata, 1123. + rotalia, 1123. + theocapsa, 1123. + BOTRYOCAMPIDA, 1120. + Botryocella, 1116. + borealis, 1116. + multicellaris, 1112. + nucula, 1116. + quadricellaris, 1117. + quadrigemina, 1117. + tricellaris, 1116. + BOTRYOCELLIDA, 1112. + BOTRYOCYRTIDA, 1120. + Botryocyrtis, 1120. + cerebellum, 1121. + quinaria, 1121. + serpentis, 1120. + theocampe, 1121. + BOTRYODEA, 1108. + Botryopera, 1108. + cyrtoloba, 1108. + multiloba, 1109. + quadriloba, 1109. + triloba, 1108. + Botryopyle, 1112. + cephalodes, 1113. + cribrosa, 1113. + dictyocephalus, 1113. + inclusa, 1113. + sethocorys, 1112. + BOTRYOPYLIDA, 1112. + Botryostrobus, 1475. + Brachiospyris, 1037. + diacantha, 1038. + ocellata, 1038. + Buccinosphaera, 99. + invaginata, 99. + tubaria, 99. + + Callimitra, 1216. + agnesae, 1217. + annae, 1217. + carolotae, 1217. + elisabethae, 1218. + emmae, 1218. + Calocyclas, 1381. + amicae, 1382. + aspasia, 1385. + _barbadensis_, 1459. + _carcinus_, 1375. + casta, 1384. + erinaceus, 1383. + gigas, 1384. + hyalogaster, 1383. + minervae, 1382. + monumentum, 1385. + parthenia, 1385. + pudica, 1384. + sacerdotis, 1382. + turris, 1383. + veneris, 1381. + vestalis, 1382. + virginis, 1381. + Calocycletta, 1381. + Calocyclissa, 1383. + Calocycloma, 1384. + CALODICTYA, 481. + Calpocapsa, 1190. + Calpophaena, 1175. + enneaphylla, 1176. + ennearrhabda, 1176. + hexacorethra, 1177. + hexarrhabda, 1176. + petalospyris, 1177. + tetracorethra, 1177. + tetrarrhabda, 1176. + Caminosphaera, 111. + dendrophora, 112. + dichotoma, 112. + elongata, 111. + furcata, 111. + Cannartidium, 373. + amphicanna, 374. + amphiconicum, 373. + _amphiconus_, 372. + amphisiphon, 374. + bicinctum, 374. + mammiferum, 375. + mastophorum, 375. + _tubarium_, 339. + Cannartiscus, 372. + amphiconiscus, 372. + amphicylindrus, 373. + Cannartus, 358. + biscottus, 359. + bitubulus, 359. + violina, 358. + CANNOBELIDA, 1551. + Cannobelos, 1551. + calymmata, 1551. + cavispicula, 1551. + thalassoplancta, 1551. + CANNOBOTRYIDA, 1107. + Cannobotrys, 1109. + cortina, 1110. + dicanna, 1110. + monocanna, 1110. + pentacanna, 1111. + sagittalis, 1110. + tetracanna, 1111. + tricanna, 1110. + Cannocapsa, 801. + osculata, 801. + stethoscopium, 801. + tubulosa, 801. + Cannopilus, 1567. + calyptra, 1568. + cyrtoides, 1569. + diplostaurus, 1568. + hemisphaericus, 1569. + superstructus, 1568. + CANNOPYLEA, 1521. + CANNORRHAPHIDA, 1546. + Cannorrhaphis, 1552. + cavispicula, 1551. + lampoxanthium, 1552. + lappacea, 1552. + spathillata, 1552. + spinulosa, 1552. + Cannosphaera, 1640. + antarctica, 1640. + atlantica, 1640. + pacifica, 1641. + CANNOSPHAERIDA, 1637. + Cantharospyris, 1050. + ateuchus, 1051. + carabus, 1051. + platybursa, 1051. + radicata, 1051. + CAPSOPHRACTA, 793. + Carpocanarium, 1279. + Carpocanidium, 1280. + Carpocanistrum, 1170. + acephalum, 1171. + evacuatum, 1172. + flosculum, 1171. + giganteum, 1171. + novenum, 1171. + pyriforme, 1172. + Carpocanium, 1279. + _arachnodiscus_, 1164. + calycodes, 1279. + _campanula_, 1144. + _cornutum_, 1398. + coronatum, 1284. + cylindricum, 1281. + dactylus, 1284. + diadema, 1281. + enneaphyllum, 1281. + gemmula, 1282. + hexagonale, 1282. + irregulare, 1284. + laeve, 1280. + lanceolatum, 1280. + _macropterum_, 1283. + microdon, 1282. + palmipes, 1283. + peristomium, 1283. + petalospyris, 1283. + polypterum, 1283. + setosum, 1280. + solitarium, 1281. + trepanium, 1282. + verecundum, 1284. + virgineum, 1285. + Carpocanobium, 1282. + Carposphaera, 71. + apiculata, 73. + areca, 74. + belladonna, 74. + borassus, 75. + capillacea, 72. + cerasus, 73. + corypha, 75. + cubaxonia, 72. + entactinia, 74. + infundibulum, 72. + maxima, 76. + melissa, 73. + melitomma, 73. + micrococcus, 75. + modesta, 74. + nobilis, 75. + nodosa, 76. + prunulum, 74. + CARPOSPHAERIDA, 71. + Caryomma, 265. + irregulare, 266. + regulare, 265. + CARYOMMIDA, 265. + Caryosphaera, 86. + hexalepas, 86. + pentalepas, 86. + polysphaerica, 1763. + CARYOSPHAERIDA, 85. + CARYOSTYLIDA, 148. + Caryostylus, 148. + _ceparius_, 336. + _cepicius_, 336. + hexalepas, 148. + Castanarium, 1681. + darwini, 1681. + hookeri, 1682. + huxleyi, 1682. + lubbocki, 1682. + lyelli, 1682. + Castanella, 1683. + balfouri, 1683. + campbelli, 1683. + channeri, 1684. + horstoni, 1684. + sloggetti, 1683. + thomsoni, 1683. + wyvillei, 1683. + CASTANELLIDA, 1677. + Castanidium, 1684. + aldrichii, 1685. + bethelli, 1685. + bromleyi, 1685. + buchanani, 1685. + moseleyi, 1686. + murrayi, 1685. + wildi, 1684. + willemoesi, 1684. + Castanissa, 1686. + challengeri, 1686. + crosbiei, 1687. + hoylei, 1687. + macleani, 1687. + pearceyi, 1686. + richardsi, 1687. + Castanopsis, 1688. + fergusoni, 1688. + maclearei, 1688. + naresi, 1688. + Castanura, 1689. + carpenteri, 1689. + havergalli, 1689. + swirei, 1689. + tizardi, 1689. + CATINULIDA, 1553. + Catinulus, 1553. + catillum, 1553. + lopadium, 1553. + quadrifidus, 1553. + Cecryphalium, 1398. + lamprodiscus, 1398. + sestrodiscus, 1399. + Cenellipsis, 291. + circopora, 291. + ehrenbergii, 291. + faceta, 291. + heteropora, 292. + infundibulum, 292. + maxima, 292. + micropora, 291. + oblonga, 293. + ovulum, 292. + primitiva, 291. + Cenellipsium, 290. + Cenellipsula, 292. + Cenocapsa, 802. + nirvana, 802. + CENOCAPSIDA, 802. + CENODISCIDA, 409. + Cenodiscus, 411. + lenticula, 412. + phacoides, 411. + rotula, 412. + CENOLARCIDA, 606. + Cenolarcus, 606. + dimensivus, 607. + lentellipticus, 607. + minimus, 607. + primordialis, 607. + triaxonius, 607. + Cenosphaera, 62. + _acanthica_, 215. + anthophora, 63. + antiqua, 67. + aspera, 68. + bombus, 63. + compacta, 65. + coronata, 67. + crassa, 65. + cristata, 66. + elysia, 64. + eridani, 64. + favosa, 62. + gigantea, 67. + hexagonalis, 62. + hirsuta, 68. + inermis, 62. + lethe, 64. + marginata, 67. + maxima, 65. + _megapora_, 155. + melecta, 63. + mellifica, 62. + _micropora_, 155. + nirwana, 65. + papillata, 66. + perforata, 66. + plutonis, 64. + polygonalis, 66. + porophaena, 63. + primordialis, 61. + proserpinae, 64. + radiata, 1763. + reticulata, 66. + rosetta, 63. + setosa, 64. + solida, 65. + tenerrima, 66. + vesparia, 62. + Centrocubus, 278. + cladostylus, 278. + octostylus, 278. + polystylus, 278. + Centrospira, 495. + _perispongidium_, 495. + Cephalopyramis, 1253. + _enneactis_, 1254. + Cephalospyris, 1034. + cancellata, 1035. + ovata, 1035. + triangulata, 1035. + Cerasosphaera, 73. + _Ceratocyrtis_, 1281. + _ampliata_, 1291. + _cucullaris_, 1290. + _mitra_, 1291. + Ceratospyris, 1065. + _acuminata_, 1080. + allmersii, 1067. + _articulata_, 1048. + _ateuchus_, 1051. + _borealis_, 1075. + calorrhiza, 1069. + carnerii, 1069. + _clavata_, 1028. + _diacantha_, 1038. + _didiceros_, 1030. + _dirrhiza_, 1039. + echinus, 1068. + _fibula_, 1082. + _furcata_, 1031. + _heptaceros_, 1038. + krausei, 1068. + _longibarba_, 1054. + muelleri, 1068. + mulderi, 1067. + _ocellata_, 1038. + pentagona, 1067. + polygona, 1066. + preyeri, 1068. + radicata, 1051. + ramosa, 1069. + _setigera_, 1047. + strasburgeri, 1068. + _stylophora_, 1038. + _triceros_, 1033. + _triomma_, 1047. + _turrita_, 1050. + Ceriasparium, 819. + CERIASPIDA, 813. + Ceriaspidium, 820. + Ceriaspis, 820. + cicatricosa, 821. + favosa, 821. + icosahedra, 821. + inermis, 821. + lacunosa, 820. + scrobiculata, 820. + Ceriosphaera, 66. + _perforata_, 66. + Challengeranium, 1653. + Challengerantha, 1648. + Challengerebium, 1655. + Challengeretta, 1649. + Challengeria, 1694. + aldrichii, 1653. + _balfouri_, 1655. + bidens, 1650. + bromleyi, 1652. + campbelli, 1650. + cyrtodon, 1649. + elephas, 1651. + harstoni, 1650. + havergalli, 1651. + macleari, 1651. + murrayi, 1653. + naresii, 1648. + pyramidalis, 1649. + quadridens, 1652. + sigmodon, 1649. + sloggettii, 1649. + _swirei_, 1654. + thomsoni, 1650. + tizardi, 1656. + tridens, 1651. + trifida, 1652. + trigona, 1652. + tritonis, 1649. + wildi, 1653. + xiphodon, 1648. + CHALLENGERIDA, 1642. + Challengeridium, 1656. + Challengerilla, 1651. + Challengeroma, 1652. + Challengeron, 1654. + balfouri, 1655. + bathybium, 1658. + bethelli, 1658. + bisternum, 1657. + buchanani, 1657. + carpenterii, 1659. + channeri, 1658. + ciliatum, 1659. + cochlear, 1654. + crosbiei, 1657. + diodon, 1654. + fergusoni, 1656. + golfense, 1655. + heptacanthum, 1657. + johannis, 1659. + monodon, 1654. + moseleyi, 1658. + pearceyi, 1654. + richardsii, 1655. + swirei, 1654. + tizardi, 1656. + triangulum, 1656. + triodon, 1655. + willemoesii, 1659. + wyvillei, 1660. + Challengerosium, 1658. + CHIASTOLIDA, 736. + CHIASTOLIDINA, 738. + Chiastolus, 738. + amphicopium, 738. + _Chilomma_, 454. + _saturnus_, 454. + Chitonastrum, 537. + bathybium, 537. + dicranoides, 538. + jugatum, 537. + lyra, 538. + _regulare_, 539. + triglochin, 537. + Choenicosphaera, 102. + flammabunda, 103. + flosculenta, 103. + murrayana, 102. + nassiterna, 103. + Cinclopyramis, 1161. + cribellum, 1161. + infundibulum, 1161. + lithosestrum, 1162. + Circogonia, 1698. + dodecacantha, 1698. + icosahedra, 1698. + CIRCOGONIDA, 694. + Circoniscus, 489. + CIRCOPORIDA, 1689. + Circoporus, 1694. + characeus, 1695. + hexastylus, 1695. + octahedrus, 1695. + sexfurcus, 1694. + sexfuscinus, 1695. + Circorrhegma, 1699. + dodecahedra, 1699. + Circospathis, 1696. + furcata, 1696. + novena, 1696. + tetradeca, 1697. + tetrodonta, 1697. + Circosphaera, 63. + CIRCOSPYRIDA, 1072. + Circospyris, 1072. + gigas, 1072. + nucula, 1072. + tridentata, 1072. + Circostephanus, 1699. + coronarius, 1699. + polygonarius, 1700. + sexagenarius, 1700. + Circotympanum, 1012. + decagonium, 1013. + hexagonium, 1012. + octogonium, 1013. + Cladarachnium, 1165. + _virgultum_, 1296. + ramosum, 1165. + CLADOCOCCIDA, 51. + Cladococcus, 223. + abietinus, 226. + _acufer_, 211. + antarcticus, 225. + arborescens, 224. + bifurcus, 226. + _cervicornis_, 228. + _dentatus_, 211. + dendrites, 227. + japonicus, 225. + penicillus, 224. + pinetum, 226. + quadricuspis, 225. + scoparius, 225. + _simplex_, 216. + spinifer, 224. + stalactites, 227. + tricladus, 227. + viminalis, 226. + Cladocorona, 1177. + CLADOPHRACTA, 803. + Cladopyramis, 1160. + Cladoscenium, 1148. + ancoratum, 1149. + fulcratum, 1148. + gladiatum, 1149. + pectinatum, 1150. + pinnatum, 1149. + verticillatum, 1149. + Cladospyris, 1069. + _bibrachiata_, 1039. + _moluccana_, 1761. + _ramosa_, 1069. + _tribrachiata_, 1029. + _Clathrobursa_, 1045. + _dictyopus_, 1045. + Clathrocanidium, 1210. + Clathrocanium, 1210. + coarctatum, 1211. + diadema, 1212. + _ehrenbergii_, 1262. + reginae, 1212. + sphaerocephalum, 1211. + squarrosum, 1211. + triomma, 1211. + Clathrocorona, 1212. + _diadema_, 1212. + _reginae_, 1212. + Clathrocorys, 1219. + giltschii, 1220. + murrayi, 1219. + teuscheri, 1220. + Clathrocircus, 961. + decaporus, 962. + dictyospyris, 963. + hexaporus, 962. + multiforis, 963. + octoporus, 962. + stapedius, 962. + Clathrocyclas, 1385. + alcmenae, 1388. + basilea, 1386. + cassiopeiae, 1390. + collaris, 1387. + coscinodiscus, 1389. + danaes, 1388. + domina, 1387. + europae, 1388. + fimbriata, 1386. + jonis, 1389. + latonae, 1389. + principessa, 1386. + puella, 1387. + semeles, 1388. + Clathrocyclia, 1386. + Clathrolychnus, 1240. + araneosus, 1240. + periplectus, 1241. + Clathromitra, 1218. + pentacantha, 1219. + pterophormis, 1219. + Clathropilium, 1326. + Clathropyrgus, 1441. + _trifenestra_, 1441. + Clathrosphaera, 118. + arachnoides, 119. + circumtexta, 118. + lamellosa, 119. + CLATHROSPHAERIDA, 118. + Clathrospyris, 1052. + camelopardalis, 1052. + fusiformis, 1053. + pyramidalis, 1052. + Clistophaena, 1286. + armata, 1288. + enneolena, 1288. + hexolena, 1287. + polyolena, 1288. + pyramidalis, 1287. + ruestiana, 1287. + Coccocyclia, 468. + heliantha, 468. + liriantha, 468. + COCCODISCIDA, 455. + Coccodiscus, 461. + darwinii, 461. + goethei, 461. + lamarckii, 461. + COCCOLARCIDA, 610. + Coccolarcus, 610. + lentellipsis, 610. + platellipsis, 610. + Coccostaurus, 466. + _magniducis_, 466. + Coelacantha, 1641. + anchorata, 1641. + mammillata, 1641. + Coelagalma, 1759. + mirabile, 1759. + Coelodasea, 1739. + ramosissima, 1739. + spongiosa, 1739. + Coelodecas, 1755. + decastyla, 1755. + pentagona, 1756. + sagittaria, 1755. + COELODENDRIDA, 1728. + Coelodendrum, 1735. + bifurcum, 1735. + cervicorne, 1736. + digitatum, 1736. + flabellatum, 1737. + furcatissimum, 1735. + gracillimum, 1736. + lappaceum, 1736. + ramosissimum, 1735. + serratum, 1737. + spinosissimum, 1735. + Coelodoras, 1734. + hexagraphis, 1734. + octographis, 1734. + COELODORIDA, 1733. + COELODRYMIDA, 1737. + Coelodrymus, 1738. + ancoratus, 1738. + echinatus, 1738. + lappulatus, 1738. + COELOGRAPHIDA, 1739. + Coelographis, 1752. + gracillima, 1753. + hexastyla, 1753. + regina, 1752. + sagittella, 1753. + triangulum, 1753. + Coeloplegma, 1757. + atlanticum, 1758. + murrayanum, 1757. + tetradecastylum, 1758. + tritonis, 1758. + COELOPLEGMIDA, 1752. + Coelospathis, 1754. + ancorata, 1754. + octodactyla, 1755. + octostyla, 1754. + Coelostylus, 1756. + bisenarius, 1756. + flabellatus, 1757. + Coelothamnus, 1751. + bivalvis, 1751. + davidoffi, 1751. + maximus, 1752. + sedecimalis, 1751. + Coelothauma, 1750. + duodenum, 1750. + COELOTHOLIDA, 1749. + Coelotholus, 1749. + ancoratus, 1749. + cruciatus, 1749. + octonus, 1749. + COLEASPIDA, 861. + Coleaspis, 867. + amphilonche, 867. + coronata, 866. + hydrotomica, 867. + obscura, 866. + occulta, 867. + vaginata, 866. + COLLIDA, 9. + COLLODARIA, 9. + Collodastrum, 27. + amoeboides, 28. + pelagicum, 28. + stellatum, 28. + Collodinium, 24. + _inerme_, 25. + _nostochinum_, 25. + _volvocinum_ 25. + Collodiscus, 27. + _coeruleus_, 27. + _discoideus_, 27. + COLLOIDEA, 10. + Collophidium, 26. + _contortum_, 26. + _serpentinum_, 26. + _vermiforme_, 27. + Colloprunum, 25. + _ovatum_, 25. + _ellipsoides_, 26. + Collosphaera, 95. + globularis, 95. + huxleyi, 96. + irregularis, 97. + _ligurina_, 97. + polyhedra, 97. + polygona, 96. + primordialis, 95. + pyriformis, 96. + regularis, 95. + _spinosa_, 100. + tuberosa, 97. + _tubulosa_, 105. + COLLOSPHAERIDA, 92. + COLLOZOIDA, 23. + Collozoum, 24. + amoeboides, 28. + contortum, 26. + coeruleum, 27. + discoideum, 27. + ellipsoides, 26. + inerme, 25. + nostochinum, 25. + ovatum, 25. + pelagicum, 28. + serpentinum, 26. + stellatum, 28. + vermiforme, 27. + volvocinum, 25. + Conarachnium, 1290. + _rayanum_, 1291. + _cervus_, 1292. + _lophophaena_, 1292. + _trochus_, 1290. + CONCHARIDA, 1710. + Concharium, 1716. + bacillarium, 1718. + bivalvum, 1717. + diatomeum, 1717. + fragilissimum, 1718. + nucula, 1717. + Conchasma, 1718. + hibburites, 1719. + radiolites, 1719. + sphaerulites, 1719. + CONCHASMIDA, 1716. + Conchellium, 1720. + hippopus, 1720. + tridacna, 1720. + Conchidium, 1721. + argiope, 1722. + dimerella, 1722. + leptaena, 1722. + magasella, 1723. + productum, 1723. + rhynchonella, 1722. + terebratula, 1721. + thecidium, 1721. + Conchoceras, 1727. + caudatum, 1727. + cornutum, 1728. + Conchonia, 1723. + diodon, 1723. + tetrodon, 1724. + triodon, 1724. + CONCHOPSIDA, 1719. + Conchopsis, 1724. + aspidium, 1726. + carinata, 1725. + compressa, 1725. + lenticula, 1726. + navicula, 1727. + orbicularis, 1725. + pilidium, 1726. + _Conchura_, 1724. + _tetrodon_, 1724. + Conosphaera, 221. + orthoconus, 221. + plagioconus, 222. + platyconus, 221. + Conostrobus, 1469. + Cornustrobus, 1470. + Cornutanna, 1183. + cyrtoconus, 1184. + loxoconus, 1184. + orthoconus, 1183. + Cornutella, 1180. + _ampliata_, 1291. + annulata, 1182. + _bimarginata_, 1295. + _cassis_, 1301. + circularis, 1181. + clathrata, 1182. + _cullaris_, 1290. + curvata, 1183. + distenta, 1181. + granulata, 1182. + hexagona, 1180. + _longiseta_, 1294. + mitra, 1181. + _obtusa_, 1308. + _orthoceras_, 1294. + _profunda_, 1284. + _pseudoprofunda_, 1762. + _pseudoclathrata_, 1762. + _quadratella_, 1254. + _scalaris_, 1203. + sethoconus, 1180. + _spiniceps_, 1303. + spiralis, 1183. + stiligera, 1181. + stylophaena, 1182. + _trichostyla_, 1294. + _trochus_, 1293. + _tumens_, 1182. + _verrucosa_, 1293. + Cornutellium, 1180. + Cornutissa, 1181. + Cornutosa, 1183. + _clathrata_, 1183. + Corocalyptra, 1322. + agnesae, 1323. + elisabethae, 1323. + emmae, 1323. + ludovicae, 1324. + margarethae, 1323. + COROCYRTIDA, 1129. + CORONIDA, 967. + Coronidium, 973. + acacia, 975. + cervicorne, 974. + diadema, 974. + dyostephanus, 974. + Coronophaena, 1178. + Coronosphaera, 117. + diadema, 117. + calycina, 117. + convolvulus, 117. + Cortina, 950. + cervina, 952. + conifera, 951. + dendroides, 951. + furcata, 951. + tripus, 950. + typus, 951. + Cortinetta, 1667. + cortiniscus, 1667. + tripodiscus, 1667. + CORTINIDA, 950. + CORTINISCIDA, 963. + Cortiniscus, 963. + dipylaris, 964. + tetrapylaris, 964. + tripodiscus, 963. + tripylaris, 964. + typicus, 964. + Corythospyris, 1057. + Coscinasparium, 826. + Coscinaspidium, 828. + Coscinaspis, 826. + ceriopora, 826. + coscinopora, 826. + isopora, 828. + orthopora, 827. + parmipora, 827. + peripora, 825. + polypora, 827. + rhacopora, 827. + stigmopora, 826. + Coscinomma, 222. + amphisiphon, 222. + ectosiphon, 222. + endosiphon, 223. + macrosiphon, 223. + COSCINOMMIDA, 209. + _Craniaspis_, 827. + _parmipora_, 827. + Craspedilium, 1247. + _eupilium_, 1247. + Craspedomma, 77. + CRICOIDEA, 889. + Cromyatractus, 335. + ceparius, 336. + cepicius, 336. + tetracelyphus, 335. + tetralepus, 335. + tetraphractus, 335. + Cromyechinus, 263. + dodecacanthus, 264. + icosacanthus, 263. + polyacanthus, 264. + Cromyocarpus, 318. + quadrifarius, 318. + Cromyodruppa, 317. + cepa, 317. + mango, 318. + Cromyodrymus, 264. + abietinus, 265. + quadricuspis, 264. + Cromyomma, 261. + circumtextum, 262. + macroporum, 262. + mucronatum, 263. + perplexum, 261. + perspicuum, 262. + quadruplex, 262. + villosum, 261. + zonaster, 261. + CROMYOMMIDA, 260. + Cromyosphaera, 85. + antarctica, 85. + bigemina, 85. + cepa, 85. + _perspicua_, 262. + quadruplex, 84. + rosetta, 84. + scorodonium, 85. + CROMYOSPHAERIDA, 84. + Cromyostaurus, 167. + verticillatus, 167. + CROMYOSTYLIDA, 146. + Cromyostylus, 147. + gladius, 147. + Crucidiscus, 415. + cruciatus, 416. + cuspidatus, 416. + echinatus, 416. + endostaurus, 416. + Cryptocapsa, 1312. + bacca, 1313. + pila, 1313. + Cryptocephalus, 1252. + favosus, 1252. + _Cryptoprora_, 1252. + _microstoma_, 1252. + _ornata_, 1375. + _plutonis_, 1252. + _polyptera_, 1283. + Cubaxonium, 204. + octahedrum, 204. + spongiosum, 204. + Cubosphaera, 203. + concentrica, 203. + cubaxonia, 203. + CUBOSPHAERIDA, 169. + CUBOTHOLIDA, 677. + Cubotholonium, 682. + ellipsoides, 682. + sphaeroides, 682. + Cubotholus, 680. + octoceras, 681. + quadraticus, 680. + regularis, 680. + rhombicus, 681. + Cycladophora, 1376. + campanula, 1379. + _davisiana_, 1437. + _discoides_, 1397. + dodecapleura, 1378. + enneapleura, 1378. + _erinaceus_, 1383. + favosa, 1380. + fenestrata, 1390. + goetheana, 1375. + _gigas_, 1384. + hexapleura, 1377. + lanterna, 1377. + nonagona, 1378. + pantheon, 1379. + pyramidalis, 1377. + spatiosa, 1379. + spinosa, 1378. + stiligera, 1380. + _tabulata_, 1293. + tetrapleura, 1376. + Cyclampterium, 1371. + Cyclamptidium, 1380. + CYCLODISCARIA, 409. + Cypassis, 366. + entomocora, 367. + eucolpos, 367. + halicora, 368. + palliata, 366. + puella, 367. + Cyphanta, 360. + arachnoides, 361. + circopora, 361. + colpodes, 361. + hispida, 362. + hystrix, 362. + laevis, 361. + CYPHINIDA, 359. + Cyphinidium, 371. + _amphilophus_, 370. + amphistylium, 371. + apicatum, 371. + coronatum, 372. + Cyphinoma, 369. + Cyphinura, 370. + Cyphinus, 369. + amphacanthus, 369. + amphilophus, 370. + dixiphus, 370. + penicillatus, 370. + Cyphocolpus, 368. + didymus, 368. + virginis, 369. + Cyphonium, 363. + diattus, 364. + ceratospyris, 366. + coscinoides, 363. + cribellum, 365. + ethmarium, 363. + facettarium, 365. + hexagonium, 364. + mammarium, 364. + profundum, 365. + trinacrium, 364. + virgineum, 363. + CYRTELLARIA, 1015. + CYRTIDA, 1126. + Cyrtidosphaera, 65. + _echinoides_, 214. + _reticulata_, 66. + CYRTOCALPIDA, 1178. + Cyrtocalpis, 1185. + amphora, 1186. + _cassis_, 1301. + compacta, 1187. + gromia, 1188. + lithomitra, 1187. + obliqua, 1187. + ovulum, 1187. + reticulum, 1186. + sethopora, 1187. + urceolus, 1186. + urna, 1186. + Cyrtocapsa, 1512. + chrysalidium, 1515. + colatractus, 1414. + compacta, 1512. + cornuta, 1513. + costata, 1514. + diploconus, 1513. + fusulus, 1514. + incrassata, 1514. + inflata, 1513. + pyrum, 1513. + tetrapera, 1512. + Cyrtocapsella, 1512. + Cyrtocapsoma, 1514. + Cyrtocorys, 1457. + CYRTOIDEA, 1126. + Cyrtolagena, 1451. + _laguncula_, 1451. + Cyrtopera, 1450. + gasteroptera, 1451. + lagenella, 1451. + laguncula, 1451. + ornithoptera, 1450. + thoracoptera, 1450. + Cyrtophormis, 1459. + aculeata, 1461. + acutata, 1461. + armata, 1460. + cingulata, 1460. + cornuta, 1462. + corona, 1462. + cylindrica, 1461. + fimbriata, 1462. + ovata, 1460. + turricula, 1463. + turrita, 1462. + Cyrtophormiscus, 1460. + Cyrtophormium, 1460. + Cyrtostrobus, 1471. + Cystidium, 897. + inerme, 897. + lecythium, 897. + princeps, 897. + Cystophormis, 1165. + aerostatica, 1166. + pila, 1165. + spiralis, 1166. + tabulata, 1166. + CYTOPHORA, 1. + + Dendrocircus, 948. + arborescens, 949. + barbadensis, 950. + dodecancistra, 949. + dodecarrhiza, 949. + elegans, 949. + quadrangulus, 948. + stalactites, 950. + Dendrospyris, 1038. + arborescens, 1040. + bibrachiata, 1039. + dirrhiza, 1039. + furcata, 1039. + polyrrhiza, 1039. + ramosa, 1040. + stylophora, 1038. + Dermatosphaera, 1763. + Desmartus, 398. + larvalis, 398. + tubulatus, 399. + Desmocampe, 397. + aphrodite, 397. + atractus, 398. + catenula, 397. + taenioides, 397. + DESMOCAMPIDA, 392. + Desmospyris, 1089. + anthocyrtoides, 1090. + carpocanium, 1090. + cyrtocolpos, 1090. + mammillata, 1089. + Dicolocapsa, 1312. + megacephala, 1312. + microcephala, 1312 + platycephala, 1312. + Dicranastrum, 550. + antilope, 551. + bifurcatum, 552. + cornutum, 551. + dichotomum, 550. + furcatum, 550. + tricuspis, 551. + trifarium, 552. + wyvillei, 551. + Dictyastrella, 524. + Dictyastromma, 525. + Dictyastrum, 524. + aculeatum, 526. + angulatum, 524. + bandaicum, 525. + hexagonum, 525. + _lyra_, 538. + _taumorphum_, 537. + triactis, 526. + trirrhopalum, 525. + trispinosum, 525. + _velatum_, 545. + Dictyaspis, 865. + compacta, 865. + favosa, 865. + solidissima, 865. + _Dictyatractus_, 1361. + _fenestratus_, 1361. + Dictyocephalus, 1305. + amphora, 1305. + ampulla, 1308. + australis, 1306. + capito, 1309. + cavea, 1309. + crassiceps, 1306. + excellens, 1306. + _galeatus_, 1208. + globiceps, 1308. + hispidus, 1309. + _larvatus_, 1292. + mediterraneus, 1307. + obtusus, 1308. + ocellatus, 1306. + papillosus, 1307. + reticulum, 1307. + tabulatus, 1307. + urceolus, 1305. + Dictyoceras, 1324. + bombus, 1325. + formica, 1325. + insectum, 1324. + melitta, 1325. + virchowii, 1325. + Dictyocha, 1557. + _abnormis_, 1561. + _abyssorum_, 1559. + _aculeata_, 1565. + _anacantha_, 1565. + _asteroides_, 1564. + _binoculus_, 1565. + _bipartita_, 1563. + _bisternaria_, 1565. + _corona_, 1566. + _crux_, 1563. + _cyrtoides_, 1569. + _diadema_, 1567. + _diommata_, 1565. + _elegans_, 1564. + _elliptica_, 1556. + epiodon, 1561. + _erebi_, 1565. + fibula, 1561. + _haliomma_, 1565. + _hemisphaerica_, 1569. + _heptacanthus_, 1568. + _hexathyra_, 1565. + medusa, 1560. + _mesophthalma_, 1563. + messanensis, 1561. + navicula, 1559. + _octonaria_, 1566. + _ornamentum_, 1565. + _pentasterias_, 1564. + _polyactis_, 1566. + pons, 1559. + _ponticulus_, 1559. + quadrata, 1559. + _quinaria_, 1564. + rhombus, 1562. + _septenaria_, 1566.. + _sirius_, 1566. + _speculum_, 1565. + stapedia, 1561. + _stauracanthus_, 1566. + staurodon, 1560. + _stella_, 1565. + _superstructa_, 1568. + _tenella_, 1561. + _triacantha_, 1559. + _triactis_, 1559. + _triangula_, 1555. + _trifenestrata_, 1559. + trigona, 1764. + triommata, 1559. + tripyla, 1560. + _ubera_, 1565. + DICTYOCHIDA, 1554. + Dictyocodon, 1334. + annasethe, 1334. + carolotae, 1335. + palladius, 1335. + prometheus, 1336. + Dictyocoryne, 592. + agrigentina, 593. + charybdaea, 593. + echinata, 594. + euchitonia, 592. + pentagona, 593. + profunda, 592. + tetradiscus, 592. + tetras, 597. + trigona, 593. + Dictyocryphalus, 1308. + Dictyomitra, 1476. + articulata, 1476. + conica, 1477. + costata, 1478. + demersissima, 1478. + ehrenbergii, 1422. + eurythorax, 1477. + lineata, 1484. + macilenta, 1476. + microcephala, 1477. + multicostata, 1478. + polypora, 1477. + punctata, 1486. + ventricosa, 1503. + Dictyomitrella, 1476. + Dictyomitrissa, 1477. + Dictyomitroma, 1478. + Dictyophimium, 1195. + Dictyophimus, 1195. + arabicus, 1198. + bicornis, 1200. + brandtii, 1198. + buetschlii, 1201. + challengeri, 1196. + cienkowskii, 1200. + cortina, 1197. + craticula, 1196. + gracilipes, 1197. + hamosus, 1199. + hertwigii, 1201. + lasanum, 1197. + longipes, 1197. + lucerna, 1199. + platycephalus, 1198. + plectaniscus, 1196. + pocillum, 1200. + pyramis, 1196. + sphaerocephalus, 1195. + tridentatus, 1199. + tripus, 1195. + triserratus, 1200. + Dictyoplegma, 90. + _spongiosum_, 90. + Dictyopodium, 1352. + _bicorne_, 1332. + _challengeri_, 1231. + cothurnatum, 1353. + _eucolpum_, 1332. + eurylophus, 1352. + oxylophus, 1353. + scaphopodium, 1353. + thyrsolophus, 1354. + _trilobum_, 1333. + Dictyoprona, 1250. + Dictyoprora, 1305. + _Dictyosoma_, 90. + _spongiosum_, 90. + _trigonizon_, 1612. + Dictyospyrantha, 1073. + Dictyospyrella, 1074. + Dictyospyris, 1073. + anthophora, 1076. + biloba, 1074. + _clathrata_, 1049. + _clathrus_, 1049. + distoma, 1073. + enneastoma, 1077. + fenestra, 1075. + gigas, 1075. + hexastoma, 1077. + mammillaris, 1076. + messanensis, 1076. + polystoma, 1077. + quadriloba, 1076. + _reticulata_, 1096. + _sphaera_, 1400. + spinulosa, 1075. + stalactites, 1073. + tetrastoma, 1075. + _tridentata_, 1072. + triloba, 1074. + triomma, 1074. + tristoma, 1074. + Dictyospyrissa, 1075. + Dictyospyromma, 1076. + DICYRTIDA, 1192. + Didymocyrtis, 364. + _ceratospyris_, 366. + _entomocora_, 367. + _hexagonia_, 364. + _faceta_, 365. + Didymospyris, 367. + _colpodes_, 367. + _entomocora_, 367. + Dioniscus, 486. + Diplactinium, 470. + Diplactura, 469. + diplobrachia, 469. + diploconus, 470. + Diplacterium, 469. + DIPLOCONIDA, 881. + Diploconium, 886. + Diploconulus, 885. + Diploconus, 885. + amalla, 885. + cotyliscus, 886. + cyathiscus, 885. + cylindrus, 885. + fasces, 886. + hexaphyllus, 886. + saturnus, 886. + Diplocolpium, 887. + Diplocolpulus, 880. + Diplocolpus, 887. + costatus, 887. + cristatus, 887. + dentatus, 888. + serratus, 888. + sulcatus, 888. + Diplocyclas, 1392. + bicincta, 1393. + bicorona, 1392. + bizonalis, 1373. + DIPLOPHRACTA, 847. + Diplosphaera, 246. + denticulata, 247. + dictyota, 247. + gracilis, 247. + hexagonalis, 246. + ornata, 246. + polygonalis, 247. + reticulata, 248. + _spinosa_, 245. + _stellata_, 251. + triglochin, 248. + DIPLOSPHAERIDA, 230. + DIPLOZONARIA, 640. + Dipocoronis, 980. + Dipocubus, 993. + Diporasparium, 816. + DIPORASPIDA, 808. + Diporaspidium, 817. + Diporaspis, 816. + circopora, 816. + nephropora, 816. + zygopora, 817. + DIPOSPYRIDA, 1035. + Dipospyris, 1036. + bipes, 1036. + chelifer, 1037. + cubus, 1036. + forcipata, 1037. + irregularis, 1037. + mystax, 1036. + sigmopodium, 1037. + DISCIDA, 402. + DISCOIDEA, 402. + DISCOPYLIDA, 571. + Discospira, 495. + _accrescens_, 499. + _bilix_, 496. + _deformis_, 498. + _duplex_, 497. + _helicoides_, 496. + _operculina_, 496. + _spiralis_, 496. + DISCOSPIRIDA, 481. + Discopyle, 573. + elliptica, 573. + osculata, 573. + Discozonium, 571. + cyclonium, 571. + hexagonium, 572. + trigonium, 572. + Disolenia, 113. + Distephanolithis, 970. + Distephanus, 1562. + aculeatus, 1565. + asteroides, 1564. + corona, 1566. + crux, 1563. + diadema, 1567. + mesophthalmus, 1563. + octogonius, 1567. + octonarius, 1566. + ornamentum, 1565. + pentasterias, 1564. + _rotundus_, 1565. + sirius, 1566. + speculum, 1565. + stauracanthus, 1564. + Distriactis, 436. + alternatus, 437. + amphithectus, 437. + corallanthus, 437. + lirianthus, 436. + palmanthus, 437. + Dizonium, 635. + amphacanthum, 636. + circulare, 635. + ellipticum, 635. + octacanthum, 636. + pleuracanthum, 636. + stauracanthum, 636. + transversum, 635. + Dodecaspis, 834. + tricinata, 834. + trizonia, 835. + Doracantha, 756. + dorataspis, 756. + Doratasparium, 813. + DORATASPIDA, 802. + Dorataspidium, 814. + Dorataspis, 813. + _bipennis_, 809. + _cataphracta_, 810. + _costata_, 812. + _diodon_, 837. + fusigera, 813. + gladiata, 815. + loricata, 814. + macracantha, 814. + macropora, 814. + micropora, 815. + _parmipora_, 827. + _polyancistra_, 840. + polypora, 815. + typica, 815. + _solidissima_, 865. + Dorcadospyris, 1040. + antilope, 1041. + decussata, 1041. + dentata, 1040. + dinoceras, 1041. + lunulata, 1041. + Dorypelta, 857. + dodecaspis, 858. + furcata, 857. + gladiata, 857. + lithoptera, 858. + ramosa, 857. + stauroptera, 857. + tessaraspis, 858. + tetrodon, 857. + Dorypeltarium, 856. + Dorypeltidium, 857. + Dorypeltonium, 858. + Druppatractus, 324. + accipenser, 325. + belone, 325. + coronatus, 326. + diodon, 327. + hippocampus, 324. + ichthydium, 324. + laevis, 327. + pisciculus, 328. + ostracion, 326. + testudo, 325. + xiphias, 327. + Druppocarpus, 311. + ananassa, 311. + borassus, 312. + castanea, 311. + chamaerops, 312. + corypha, 312. + Druppula, 308. + areca, 309. + caryota, 309. + cocos, 308. + drupa, 308. + elliptica, 310. + nucula, 310. + oliva, 310. + ovata, 309. + pandanus, 308. + phoenix, 308. + prunum, 310. + DRUPPULIDA, 306. + Drymosphaera, 248. + cladophora, 249. + dendrophora, 249. + furcata, 249. + hexagonalis, 248. + polygonalis, 249. + Drymospira, 694. + DYOPRUNIDA, 288. + DYOSPHAERIDA, 52. + DYOSTEPHIDA, 932. + Dyscollosphaera, 96. + DYSTYMPANIDA, 1006. + Dystympanium, 1006. + dictyocha, 1007. + distephanus, 1007. + medusa, 1007. + + Echinactura, 480. + asteriscus, 480. + culcita, 480. + goniaster, 480. + Echinaspis, 833. + diadema, 833. + dichotoma, 832. + echinoides, 833. + Echinocalpis, 1170. + Echinocapsa, 1190. + ECHINOCYSTIDA, 1. + Echinomma, 257. + aculeatum, 258. + cidaris, 257. + diadema, 258. + echinidium, 257. + sphaerechinus, 258. + toxopneustes, 259. + trinacrium, 258. + _Echinosphaera_, 638. + _datura_, 638. + ECTOLITHIA, lxxii. + Elaphococcus, 227. + cervicornis, 228. + dichotomus, 229. + drymodes, 229. + elaphoceras, 228. + furcatus, 228. + umbellatus, 229. + umbellifer, 228. + Elaphospyris, 1056. + alcicornis, 1057. + capricornis, 1056. + cervicornis, 1057. + damaecornis, 1057. + heptaceros, 1056. + Elatomma, 242. + irregulare, 243. + juniperinum, 243. + penicillus, 243. + pinetum, 242. + scoparium, 242. + ELLIPSIDA, 299. + Ellipsidium, 294. + artocarpus, 294. + datura, 294. + echinidium, 295. + opuntia, 295. + pandanidium, 294. + Ellipsostylus, 299. + aquila, 300. + avicularis, 299. + ciconia, 300. + columba, 300. + gallinula, 301. + hirundo, 301. + megadictya, 301. + ornithoides, 299. + psittacus, 300. + Ellipsoxiphus, 296. + atractus, 298. + bipolaris, 287. + claviger, 297. + elegans, 296. + flosculus, 296. + fragilis, 296. + parvoforaminus, 297. + suessi, 297. + Ennealacorys, 1374. + Enneaphormis, 1246. + _rotula_, 1246. + _Enneaplegma_, 929. + _enneacantha_, 929. + Enneapleuris, 1257. + Entocannula, 1660. + circularis, 1661. + hirsuta, 1661. + infundibulum, 1661. + subglobosa, 1661. + ENTOLITHIA, lxxii. + Ethmosphaera, 69. + conosiphonia, 69. + leptosiphonia, 70. + macrosiphonia, 70. + minuta, 1762. + pachysiphonia, 70. + polysiphonia, 70. + siphonophora, 69. + siphonophorites, 1762. + stenosiphonia, 70. + vulgaris, 1762. + ETHMOSPHAERIDA, 61. + Eucecryphalium, 1221. + Eucecryphalus, 1220. + campanella, 1223. + corocalyptra, 1221. + cuvieri, 1222. + gegenbauri, 1222. + halicalyptra, 1221. + _huxleyi_, 1215. + _laevis_, 1213. + muelleri, 1222. + _schultzei_, 1216. + Euchitonia, 532. + acuta, 536. + amoena, 1762. + beckmannii, 534. + carcinus, 535. + clathrata, 1762. + crevolensis, 1762. + cruciata, 533. + dubia, 1762. + echinata, 536. + elegans, 535. + _euclidis_, 531. + furcata, 532. + _gegenbauri_, 439. + grandis, 1762. + _leydigii_, 530. + _koellikeri_, 530. + _krohnii_, 539. + lanceolata, 434. + muelleri, 533. + muellerites, 1762. + stoehrii, 534. + triangulum, 533. + virchowii, 535. + ypsiloides, 536. + zittelii, 534. + EUCHITONIDA, 516. + Eucollosphaera, 95. + EUCORONIDA, 976. + Eucoronis, 976. + angulata, 978. + arborescens, 978. + cervicornis, 978. + challengeri, 978. + laevigata, 977. + nephrospyris, 977. + perspicillum, 977. + EUCYRTIDINA, 1127. + Eucyrtidium, 1487. + _acanthocephalum_, 1421. + _acephalum_, 1484. + _acuminatum_, 1488. + _acutatum_, 1461. + _aegaeum_, 1400. + _alauda_, 1418. + _amplum_, 1402. + _ampulla_, 1251. + _annulatum_, 1481. + _anomalum_, 1492. + anthophorum, 1497. + _antilope_, 1404. + _apiculatum_, 1404. + _aquilonare_, 1504. + _arctum_, 1414. + _argus_, 1472. + _armadillo_, 1302. + armatum, 1495. + _articulatum_, 1476. + _asperum_, 1408. + _attenuatum_, 1417. + _auritum_, 1482. + _australe_, 1487. + _barbadense_, 1406. + _biauritum_, 1411. + _bicorne_, 1421. + buetschlii, 1492. + _campanulatum_, 1400. + _cancrinum_, 1299. + _carinatum_, 1316. + _cassis_, 1424. + _cervus_, 1292. + chrysalidium, 1490. + cienkowskii, 1493. + _compactum_, 1512. + conostoma, 1495. + _cornutella_, 1473. + _coronatum_, 1411. + _cranoides_, 1322. + _crassiceps_, 1306. + _creticum_, 1415. + _cryptocephalum_, 1426. + _cryptoprora_, 1423. + _cuspidatum_, 1473. + _cylindricum_, 1406. + _davisianum_, 1437. + _demersissimum_, 1478. + _diaphanum_, 1505. + doliolum, 1489. + ehrenbergii, 1495. + _elegans_, 1406. + elongatum, 1493. + _embolum_, 1369. + eruca, 1493. + _euporum_, 1502. + _excellens_, 1306. + _fastosum_, 1369. + _ficus_, 1403. + _fistuligerum_, 1498. + fusiforme, 1489. + galatheae, 1492. + galea, 1492. + _gemmatum_, 1425. + _gracile_, 1295. + hertwigii, 1491. + _heteroporum_, 1506. + hexagonatum, 1489. + _hillaby_, 1402. + _hispidum_, 1506. + _hyperboreum_, 1486. + _imbricatum_, 1483. + _incrassatum_, 1514. + _increscens_, 1506. + _infraculeatum_, 1519. + lagena, 1491. + _lagenoides_, 1498. + _lineatum_, 1484. + _macilentum_, 1476. + _megaloporum_, 1425. + _microcephalum_, 1477. + _microporum_, 1474. + _microtheca_, 1407. + _mongolfieri_, 1251. + montiparum, 1493. + _multiseriatum_, 1505. + _nassa_, 1293. + _nereidum_, 1502. + _nucula_, 1423. + _obstipum_, 1484. + _ocellatum_, 1306. + ovatum, 1495. + _pachyderma_, 1483. + _papillosum_, 1307. + _pauperum_, 1482. + _picus_, 1472. + _pirum_, 1423. + _platycephalum_, 1502. + _pleuracanthum_, 1300. + profundissimum, 1480. + _punctatum_, 1486. + _pupa_, 1412. + _pusillum_, 1406. + _quadrarticulatum_, 1504. + _raphanus_, 1498. + _reticulum_, 1307. + scalarium, 1484. + _scolopax_, 1416. + _seriolatum_, 1486. + _sipho_, 1497. + _sphaerophilum_, 1418. + spinosum, 1490. + _stephanophorum_, 1410. + stoehrii, 1494. + _subacutum_, 1300. + teuscheri, 1491. + _tornatum_, 1473. + _trachelium_, 1405. + tricinctum, 1464. + _trochus_, 1280. + tropezianum, 1488. + _tumidulum_, 1506. + _turgidulum_, 1415. + _versipellis_, 1425. + _zancleum_, 1399. + _zanguebaricum_, 1400. + Eucyrtis, 1488. + Eucyrtomphalus, 1221. + Euphysetta, 1670. + amphicodon, 1670. + hybocodon, 1670. + staurocodon, 1670. + EUPHYSETTIDA, 1666. + Euscenarium, 1146. + Euscenidium, 1147. + Euscenium, 1146. + archicyrtis, 1146. + furcatum, 1147. + hemisphaericum, 1147. + plectaniscus, 1146. + quadratum, 1148. + ramosum, 1148. + tricolpium, 1147. + tripospyris, 1147. + Eusyringium, 1496. + cannostoma, 1499. + conosiphon, 1496. + fistuligerum, 1498. + lagenoides, 1498. + leptosiphon, 1497. + macrosiphon, 1487. + pachysiphon, 1496. + rhaphanus, 1498. + sipho, 1497. + siphonostoma, 1499. + EUTYMPANIDA, 1007. + Eutympanium, 1013. + coronarium, 1014. + dodecarium, 1014. + militare, 1014. + musicantum, 1013. + octonarium, 1014. + + _Flustrella_, 492. + _bilobata_, 527. + _concentrica_, 492. + _cyclia_, 494. + _haliomma_, 692. + _macropora_, 493. + _micromma_, 1761. + _spiralis_, 496. + + Gamospyris, 1042. + annulus, 1042. + circulus, 1042. + Gazelletta, 1670. + bifurca, 1672. + cyrtonema, 1671. + dendronema, 1674. + furcata, 1672. + hexanema, 1671. + macronema, 1671. + melusina, 1674. + orthonema, 1671. + pectinata, 1672. + penicillata, 1672. + pinnata, 1672. + robusta, 1673. + schleinitzii, 1673. + studeri, 1673. + trispathilla, 1673. + GAZELLETTIDA, 1666. + Giraffospyris, 1056. + _heptaceros_, 1076. + Gorgonetta, 1675. + bisenaria, 1675. + carmarina, 1675. + geryonia, 1675. + mirabilis, 1674. + Gorgospyris, 1069. + ehrenbergii, 1070. + eurycolpos, 1071. + lamellosa, 1071. + liriope, 1071. + medusa, 1070. + medusetta, 1070. + polypus, 1070. + schizopodia, 1071. + thamnopodia, 1071. + Gorgospyrium, 1070. + + Haeckeliana, 1702. + darwiniana, 1702. + goetheana, 1702. + maxima, 1701. + lamarckiana, 1701. + murrayana, 1702. + porcellana, 1701. + HAECKELINIDA, 1700. + Hagiastrum, 542. + bramae, 543. + buddhae, 542. + christi, 543. + _cornutum_, 551. + mohammedis, 543. + mosis, 543. + _rhopalophorum_, 541. + Halicapsa, 1189. + hystrix, 1191. + lithapium, 1190. + papillata, 1190. + prunoides, 1190. + pyriformis, 1191. + triglochin, 1190. + Halicalyptra, 1168. + ampulla, 1169. + campanula, 1169. + _cancellata_, 1167. + castanella, 1170. + _cornuta_, 1398. + _fimbriata_, 1387. + _galea_, 1136. + novena, 1169. + _orci_, 1397. + petalospyris, 1169. + _setosa_, 1280. + spinosa, 1170. + virginica, 1169. + HALICALYPTRINA, 1127. + Haliomma, 230. + _amphiaspis_, 1761. + _amphidiscus_, 447. + _amphisiphon_, 374. + antarcticum, 238. + _apertum_, 159. + _apiculatum_, 73. + arachnium, 230. + _asperum_, 344. + _asteracanthion_, 196. + beroes, 238. + boreale, 237. + capense, 235. + capillaceum, 236. + castanea, 232. + _cenosphaera_, 291. + circumtextum, 233. + clavatum, 239. + compactum, 239. + _contiguum_, 439. + _crenatum_, 314. + datura, 232. + denticulatum, 235. + _didymocyrtis_, 366. + _didymum_, 367. + _dixyphos_, 135. + duodecinum, 233. + _echinaster_, 240. + _echinoides_, 842. + _ellipticum_, 310. + enneaxiphos, 234. + _entactinia_, 74. + erinaceum, 236. + favosum, 231. + _gracile_, 1761. + grande, 235. + _helianthus_, 446. + _hexacanthum_, 184. + hexagonium, 230. + _hexagonum_, 138. + hispidum, 136. + horridum, 232. + _humboldtii_, 449. + _hystrix_, 854. + _inerme_, 80. + _infundibuliforme_, 72. + _lagena_, 527. + _lens_, 1761. + ligurinum, 1764. + lirianthus, 232. + longispinum, 235. + macrodoras, 238. + _medusa_, 80. + megaporum, 233. + melitomma, 231. + _modestum_, 74. + _nitidum_, 1761. + _oblongum_, 1761. + _octacanthum_, 442. + _oculatum_, 234. + _ovatum_, 309. + patagonicum, 239. + permagnum, 239. + _perspicuum_, 162. + _phacodiscus_, 447. + _polyacanthum_, 350. + _pyriforme_, 1191. + _quadruplex_, 262. + _radians_, 423. + _radiatum_, 423. + _radicatum_, 1051. + regulare, 231. + rhodococcus, 237. + _scutum_, 1761. + _sexaculeatum_, 186. + _sol_, 446. + spinulosum, 237. + _tabulatum_, 871. + tenellum, 236. + tenuispinum, 234. + _tetracanthum_, 164. + _triactis_, 432. + _trinacrium_, 254. + _triplex_, 314. + _umbonatum_, 449. + _virginicum_, 1169. + wyvillei, 238. + Haliommantha, 230. + HALIOMMATIDA, 230. + _Haliommatidium_, 842. + _echinoides_, 842. + _fenestratum_, 869. + _ligurinum_, 1764. + _muelleri_, 871. + _tetragonopum_, 845. + HALIOMMATINA, 51. + Haliommetta, 233. + HALIOMMIDA, 230. + Haliommilla, 236. + Haliommura, 237. + Haliphormis, 1166. + costata, 1167. + lagena, 1167. + HAPLOPHRACTA, 847. + HAPLOZONARIA, 632. + Heliocladus, 451. + _dendrophorus_, 451. + _furcatus_, 451. + Heliodendrum, 452. + HELIODISCIDA, 444. + Heliodiscus, 444. + amphidiscus, 447. + apollinis, 450. + asteriscus, 445. + cingillum, 448. + echiniscus, 448. + glyphodon, 446. + _grottense_, 451. + helianthus, 446. + humboldti, 449. + marginatus, 449. + _medusinus_, 438. + pertusus, 448. + phacodiscus, 447. + polymorphus, 447. + siculus, 446. + simplex, 1762. + sol, 446. + solaster, 447. + sulcatus, 449. + trigonodon, 445. + trochiscus, 445. + umbonatus, 449. + zoroaster, 450. + Heliodrymus, 450. + dendrocyclus, 451. + furcatus, 451. + grottensis, 451. + setosus, 452. + ramosus, 452. + viminalis, 452. + HELIOSESTRIDA, 427. + Heliosestrum, 438. + aegineta, 440. + contiguum, 439. + craspedotum, 441. + _glyphodon_, 446. + irregulare, 440. + liriope, 439. + medusinum, 438. + octagonium, 441. + octangulum, 441. + octastrum, 438. + octonum, 440. + quadrigeminum, 439. + solarium, 439. + Heliosoma, 240. + duodecilla, 241. + echinaster, 240. + elegans, 240. + hastatum, 241. + indicum, 241. + radians, 240. + Heliosphaera, 217. + actinota, 218. + castenella, 219. + coronata, 219. + cristata, 219. + echinoides, 218. + echinoidites, 1762. + elector, 220. + elegans, 218. + floribunda, 219. + heteracantha, 220. + hexagonaria, 217. + hyperionis, 220. + _inermis_, 62. + _insignis_, 212. + pectinata, 218. + polygonaria, 220. + solaris, 221. + _tenuissima_, 210. + HELIOSPHAERIDA, 209. + Heliostaurus, 434. + _cruciatus_, 434. + Heliostylus, 429. + _dentatus_, 429. + _serratus_, 429. + _Heptaplegma_, 929. + _heptacantha_, 929. + HEXACARYIDA, 202. + Hexacaryum, 203. + arborescens, 203. + Hexacolparium, 880. + Hexacolpidium, 880. + Hexacolpus, 880. + conifer, 880. + dodecodus, 881. + infundibulum, 881. + nivalis, 880. + trypanon, 881. + Hexaconarium, 876. + Hexaconidium, 877. + Hexacontarium, 200. + dentatum, 200. + clavatum, 200. + HEXACONTIDA, 191. + Hexacontium, 192. + antarcticum, 197. + asteracanthion, 196. + axophaenum, 196. + axotrias, 192. + circumtextum, 193. + clavigerum, 195. + drymodes, 198. + favosum, 194. + floridum, 195. + furcatum, 198. + gladiatum, 198. + hexaconicum, 196. + hexactis, 192. + hexagonale, 194. + laevigatum, 193. + octahedrum, 193. + papillosum, 197. + periplectum, 199. + phaenaxonium, 192. + polygonale, 197. + prionacanthum, 195. + sceptrum, 194. + setosum, 198. + triplosphaerium, 193. + Hexaconus, 876. + ciliatus, 876. + coronatus, 877. + echinatus, 878. + serratus, 877. + vaginatus, 877. + velatus, 877. + Hexacorethra, 1048. + _magica_, 1048. + Hexacoronis, 981. + _Hexacromidium_, 202. + _arachnoides_, 202. + HEXACROMYIDA, 201. + Hexacromyum, 201. + arachnoides, 202. + _cubaxonium_, 303. + elegans, 201. + octahedrum, 202. + quadrigatum, 201. + _Hexactura_, 560. + _orchidacea_, 560. + Hexadendron, 199. + bipinnatum, 200. + quadricuspis, 199. + Hexadoras, 205. + axophaena, 205. + lychnosphaera, 205. + octahedrum, 205. + HEXADORIDA, 205. + Hexadoridium, 206. + streptacanthum, 206. + Hexalacorys, 1372. + Hexalasparium, 874. + HEXALASPIDA, 872. + Hexalaspidium, 875. + Hexalaspis, 874. + heliodiscus, 875. + hexaglypha, 876. + hexalastrum, 875. + _nivalis_, 880. + sexalata, 875. + stellata, 875. + Hexalastrum, 559. + crinanthum, 559. + _geryonidum_, 560. + orchidaceum, 560. + palmanthum, 559. + Hexalatractus, 1393. + fusiformis, 1394. + sexalatus, 1394. + Hexaloncharium, 190. + hystricinum, 191. + octahedrum, 190. + philosophicum, 190. + Hexalonche, 179. + amphisiphon, 182. + anaximandri, 182. + anaximenis, 183. + aristarchi, 185. + aspera, 184. + brevicornis, 181. + castanella, 184. + conicornis, 181. + cristata, 183. + curvicornis, 181. + ekphantaea, 185. + favosa, 180. + geometrica, 184. + grandis, 182. + heracliti, 187. + hexacantha, 184. + hystricina, 187. + octahedra, 181. + octocolpa, 183. + phaenaxonia, 180. + philosophica, 186. + pythagoraea, 185. + rosetta, 180. + seleuci, 186. + serrata, 183. + setosa, 187. + sexaculeata, 186. + xenophanis, 187. + HEXALONCHIDA, 179. + Hexalonchidium, 191. + axonometrum, 191. + Hexancistra, 188. + ancorata, 188. + mirabilis, 189. + quadricuspis, 189. + tricuspis, 188. + triserrata, 188. + _Hexapitys_, 189. + _mirabilis_, 189. + Hexaplagia, 915. + antarctica, 915. + arctica, 915. + australis, 916. + collaris, 916. + HEXAPLAGIDA, 915. + Hexaplecta, 927. + triaxonia, 927. + tricladonia, 927. + HEXAPLECTIDA, 927. + Hexapleuris, 1257. + HEXAPYLIDA, 567. + Hexapyle, 568. + circularis, 569. + dodecantha, 569. + hexacantha, 569. + polyacantha, 570. + sexangula, 568. + triacantha, 569. + triangula, 568. + HEXASPYRIDA, 1046. + Hexaspyridium, 1047. + Hexaspyris, 1046. + alterna, 1047. + articulata, 1048. + buetschlii, 1047. + hexacorethra, 1048. + ophirensis, 1048. + setigera, 1047. + spinosa, 1048. + Hexastylarium, 177. + elongatum, 178. + heteraxonium, 177. + quadratum, 178. + HEXASTYLIDA, 171. + Hexastylidium, 178. + rhomboides, 178. + spirale, 179. + Hexastylus, 171. + biantis, 172. + brevispinus, 175. + chilonis, 174. + cleobuli, 174. + cochleatus, 174. + conifer, 176. + contortus, 177. + dimensivus, 175. + dictyotus, 176. + favosus, 172. + hirsutus, 176. + longispinus, 175. + longissimus, 172. + marginatus, 176. + maximus, 173. + minimus, 172. + periandri, 173. + phaenaxonius, 171. + pittaci, 173. + sapientum, 171. + setosus, 174. + solonis, 173. + spiralis, 177. + thaletis, 172. + triaxonius, 175. + Hexinastrum, 560. + geryonidum, 560. + Hexonasparium, 878. + Hexonaspidium, 879. + Hexonaspis, 879. + hastata, 879. + heliosestrum, 878. + hexagona, 879. + hexapleura, 879. + Hexoniscus, 488. + Histiastrum, 544. + boseanum, 546. + _brunonis_, 548. + circulare, 546. + coronatum, 546. + _democriti_, 548. + excisum, 544. + _fasciatum_, 535. + gladiatum, 545. + _lurianense_, 1762. + pentadiscus, 546. + quadrigatum, 544. + quaternarium, 545. + _straussii_, 547. + _ternarium_, 531. + _trinacrium_, 530. + velatum, 545. + _ypsiloides_, 536. + Holosiphonia, 104. + HOLOTRYPASTA, 5. + Hylaspis, 846. + barbata, 847. + coronata, 847. + serrulata, 846. + Hymenactura, 473. + archimedis, 473. + copernici, 475. + hexagona, 474. + ptolomaei, 475. + pythagorae, 474. + trigona, 474. + Hymenactinium, 475. + Hymenacturium, 474. + Hymenastrella, 530. + Hymenastromma, 531. + Hymeniastrum, 530. + archimedis, 531. + euclidis, 531. + guembelii, 530. + koellikeri, 530. + leydigii, 530. + pythagorae, 531. + ternarium, 531. + trigonarium, 532. + Hystrichasparium, 822. + Hystrichaspidium, 823. + Hystrichaspis, 822. + armata, 824. + cristata, 823. + divaricata, 824. + dorsata, 823. + foveolata, 824. + fruticata, 825. + furcata, 822. + pectinata, 822. + serrata, 825. + sulcata, 824. + + ICOSACANTHA, 717. + Icosasparium, 843. + Icosaspidium, 845. + Icosaspis, 844. + cruciata, 844. + elegans, 844. + icosahedra, 845. + icosastaura, 846. + multiforis, 845. + ornata, 844. + spectabilis, 845. + tabulata, 843. + tetragonopa, 845. + + Lampoxanthium, 36. + _brevispiculum_, 36. + octoceras, 37. + pandora, 38. + punctatum, 37. + tetractinium, 37. + Lamprocyclas, 1390. + aegles, 1391. + bajaderae, 1392. + deflorata, 1391. + maritalis, 1390. + nuptialis, 1390. + reginae, 1391. + saltatricis, 1391. + Lamprocyclia, 1390. + Lamprocycloma, 1392. + Lamprodiscus, 1212. + coscinodiscus, 1213. + laevis, 1214. + monoceros, 1213. + tricostatus, 1213. + Lampromitra, 1214. + arborescens, 1216. + coronata, 1214. + dendrocorona, 1216. + furcata, 1215. + huxleyi, 1215. + pyramidalis, 1215. + quadricuspis, 1214. + schultzei, 1216. + LAMPROSPYRIDA, 1092. + Lamprospyris, 1093. + darwinii, 1094. + hookeri, 1094. + huxleyi, 1094. + lyelli, 1094. + spenceri, 1095. + Lamprotripus, 1199. + _horridus_, 1201. + _spinosus_, 1201. + _squarrosus_, 1200. + Lampterium, 1376. + Lamptidium, 1377. + Lamptonium, 1378. + LARCARIDA, 605. + Larcarium, 608. + amphistylum, 608. + axostylum, 609. + chaetostylum, 609. + hexastylum, 608. + octostylum, 609. + polystylum, 609. + staurostylum, 608. + Larcidium, 611. + axacanthum, 611. + dissacanthum, 611. + dodecanthum, 612. + hexacanthum, 611. + octacanthum, 612. + polyacanthum, 612. + LARCOIDEA, 599. + Larcospira, 696. + lentelliptica, 696. + oliva, 697. + quadrangula, 696. + sexangula, 696. + Larcospirema, 696. + LARCOSPIRIDA, 695. + Larcospironium, 697. + LARNACALPIDA, 619. + Larnacalpis, 620. + lentellipsis, 620. + macrococcus, 621. + phacodiscus, 620. + subsphaerica, 621. + triaxonia, 621. + Larnacantha, 621. + bicruciata, 623. + cladacantha, 623. + decacantha, 624. + dissacantha, 622. + dodecantha, 624. + drymacantha, 624. + hexacantha, 622. + octacantha, 623. + prismatica, 623. + quadricornis, 622. + stauracantha, 622. + LARNACIDA, 614. + Larnacidium, 618. + hexabelonium, 619. + polybelonium, 619. + staurobelonium, 619. + Larnacilla, 617. + medullaris, 618. + prometor, 618. + subglobosa, 618. + typus, 617. + LARNACILLIDA, 617. + Larnacoma, 625. + hexagonium, 625. + lentellipticum, 625. + quadruplex, 625. + Larnacospongus, 626. + larnacillifer, 626. + tetrapylifer, 626. + Larnacostupa, 627. + dendrophora, 627. + octacantha, 627. + spinosa, 627. + Leptarachnium, 1248. + _aurelia_, 1248. + Leptosphaera, 244. + ciliata, 245. + hexagonalis, 244. + polygonalis, 245. + reticulum, 246. + serrata, 245. + spinosa, 245. + stellata, 245. + Liosphaera, 76. + hexagonia, 76. + peridromium, 77. + polypora, 78. + porulosa, 77. + rhodococcus, 77. + LIOSPHAERIDA, 59. + Liriospyris, 1049. + amphithecta, 1050. + clathrata, 1049. + heteropoda, 1050. + hexapoda, 1049. + turrita, 1050. + Lithapium, 303. + halicapsa, 303. + monocyrtis, 304. + pyriforme, 303. + Litharachnium, 1163. + arachnodiscus, 1164. + araneosum, 1163. + discoides, 1164. + epeira, 1164. + pilidium, 1164. + _quadratella_, 1254. + tentorium, 1163. + Lithatractus, 319. + carduelis, 321. + cirsium, 321. + conifer, 322. + conostylus, 323. + convallaria, 320. + echiniscus, 321. + fragilis, 319. + gamoporus, 323. + hexagonalis, 319. + jugatus, 323. + leptostylus, 320. + lobatus, 322. + pachystylus, 320. + rosetta, 322. + LITHELIDA, 688. + Lithelius, 693. + alveolina, 694. + arborescens, 695. + capreolus, 694. + primordialis, 694. + solaris, 695. + spiralis, 693. + LITHOBOTRYIDA, 1111. + Lithobotrys, 1117. + _adspersa_, 1116. + _biceps_, 1113. + _borealis_, 1116. + _cribrosa_, 1113. + _denticulata_, 1013. + _galea_, 1123. + geminata, 1118. + _inflata_, 1123. + lithocorythium, 1118. + mascula, 1119. + nasuta, 1118. + _nucula_, 1116. + orchidea, 1119. + ornata, 1118. + _quadriloba_, 1109. + sphaerothorax, 1119. + _stiligera_, 1088. + _triloba_, 1108. + Lithocampe, 1501. + _acuminata_, 1488. + _ampullacea_, 1402. + _anomala_, 1442. + aquilonaris, 1504. + _arcta_, 1414. + _auricula_, 1482. + _aurita_, 1482. + _australis_, 1487. + clava, 1507. + _compressa_, 1516. + _corbula_, 1761. + diaphana, 1505. + diploconus, 1505. + _eminens_, 1487. + eupora, 1502. + _fimbriata_, 1462. + _fusiformis_, 1503. + _galea_, 1492. + _heteropora_, 1506. + _hexacola_, 1507. + _heptacola_, 1506. + _hirundo_, 1356. + hispida, 1506. + _hyperborea_, 1486. + _increscens_, 1506. + _lagena_, 1491. + _lineata_, 1484. + meta, 1507. + multiseriata, 1505. + nereidum, 1502. + octocola, 1505. + ovata, 1504. + platycephala, 1502. + polycola, 1508. + _punctata_, 1486. + quadrarticulata, 1504. + radicula, 1503. + _seriolata_, 1486. + _sinuosa_, 1761. + _solitaria_, 1281. + _subligata_, 1518. + _tropeziana_, 1488. + tumidula, 1506. + urceolata, 1507. + ventricosa, 1503. + LITHOCAMPIDA, 1467. + Lithocampium, 1504. + _eurythorax_, 1474. + Lithocampula, 1502. + _Lithocarpium_, 1172. + _pyriforme_, 1172. + Lithochytridium, 1363. + LITHOCHYTRINA, 1127. + Lithochytris, 1362. + _barbadensis_, 1239. + cortina, 1362. + galeata, 1363. + lanterna, 1364. + lucerna, 1364. + pileata, 1363. + pteropus, 1364. + pyramidalis, 1364. + pyriformis, 1362. + _triangula_, 1240. + tripodium, 1363. + vespertilio, 1365. + Lithochytrodes, 1362. + LITHOCIRCIDA, 940. + Lithocircus, 943. + annularis, 943. + _annulus_, 1761. + crambessa, 944. + decimalis, 944. + furcatus, 945. + haeckelii, 1762. + hexablastus, 944. + magnificus, 945. + _mesocena_, 132. + _productus_, 948. + quadricornis, 944. + rhombus, 1762. + tarandus, 944. + _triangularis_, 1555. + truncatus, 1762. + _vinculatus_, 975. + Lithocoronis, 978. + _challengeri_, 978. + _Lithocorythium_, 1117. + _cephalodes_, 978. + _galea_, 1123. + _oxylophus_, 1118. + _platylophus_, 1118. + Lithocubus, 1011. + astragalus, 1012. + geometricus, 1011. + octacanthus, 1011. + vinculatus, 1012. + Lithocyclia, 459. + cingulata, 459. + heteropora, 460. + lenticula, 459. + monococcus, 460. + ocellus, 460. + _reticulata_, 1761. + _stella_, 467. + LITHOCYCLIDA, 459. + LITHOCYCLIDINA, 455. + Lithogromia, 1647. + diatomacea, 1647. + lenticula, 1647. + silicea, 1647. + LITHOGROMIDA, 1647. + Litholopharium, 735. + LITHOLOPHIDA, 733. + Litholophidium, 735. + Litholophonium, 736. + Litholophus, 734. + decapristis, 735. + decastylus, 735. + decimalis, 735. + fasciculus, 736. + ligurinus, 736. + penicillus, 736. + pyramidalis, 735. + rhipidium, 736. + Lithomelissa, 1203. + amphora, 1205. + bicornis, 1206. + buetschlii, 1207. + _capito_, 1257. + corythium, 1207. + decacantha, 1208. + ehrenbergii, 1204. + _falcifera_, 1207. + haeckelii, 1207. + _hertwigii_, 1207. + macroceros, 1204. + macroptera, 1204. + mediterranea, 1206. + _microptera_, 1236. + microstoma, 1205. + mitra, 1204. + pycnoptera, 1205. + _spongiosa_, 1210. + thoracites, 1206. + _ventricosa_, 1236. + Lithomespilus, 301. + _alauda_, 128. + flammabundus, 303. + flammeus, 302. + phloginus, 302. + phlogoides, 302. + _picus_, 129. + _trogon_, 129. + Lithomitra, 1483. + acephala, 1484. + australis, 1487. + chrysalis, 1485. + costata, 1485. + cylindrica, 1485. + eminens, 1487. + eruca, 1485. + hyperborea, 1486. + infundibulum, 1487. + lineata, 1484. + nodosaria, 1484. + pachyderma, 1482. + punctata, 1486. + seriolata, 1486. + Lithomitrella, 1483. + Lithomitrissa, 1485. + Lithopera, 1233. + _amblystauros_, 1311. + ananassa, 1234. + bacca, 1233. + bursella, 1234. + _denticulata_, 1073. + elongata, 1762. + globosa, 1234. + gutta, 1234. + _lagena_, 1233. + _nidus_, 1311. + _oceania_, 1232. + ovata, 1762. + _oxystauros_, 1311. + _pyrum_, 1232. + _setosa_, 1276. + Lithophyllium, 753. + condylatum, 754. + cruciatum, 754. + foliosum, 754. + gladiatum, 754. + Lithoptera, 778. + darwinii, 781. + dodecaptera, 780. + fenestrata, 781. + icosaptera, 781. + lamarckii, 779. + muelleri, 779. + quadrata, 780. + tetragona, 780. + tetraptera, 779. + Lithopteranna, 779. + Lithopterella, 780. + LITHOPTERIDA, 776. + Lithopteroma, 780. + Lithornithium, 1354. + ciconia, 1354. + _dictyoceras_, 1325. + falco, 1355. + foveolatum, 1355. + fringilla, 1355. + hirundo, 1356. + _loxia_, 1452. + _luscinia_, 1358. + trochilus, 1355. + Lithospira, 693. + Lithostrobus, 1468. + acuminatus, 1472. + argus, 1472. + botryocyrtis, 1475. + caloceras, 1471. + conulus, 1472. + cornutus, 1474. + cornutella, 1473. + cuspidatus, 1473. + cyrtoceras, 1470. + distichus, 1469. + hexagonalis, 1475. + hexastichus, 1470. + leptoceras, 1471. + lithobotrys, 1475. + macroceras, 1471. + microporus, 1474. + monostichus, 1469. + pentastichus, 1470. + picus, 1472. + quadratus, 1474. + seriatus, 1474. + tetrastichus, 1470. + tornatus, 1473. + tristichus, 1469. + Lithotympanum, 1006. + spinosum, 1006. + tuberosum, 1006. + Lonchostaurus, 772. + bifidus, 773. + bifurcus, 773. + crystallinus, 773. + lanceolatus, 773. + rhombicus, 773. + rhomboides, 772. + Lophoconus, 1403. + antilope, 1404. + apiculatus, 1404. + cervus, 1405. + cornutella, 1404. + hexagonalis, 1404. + rhinoceros, 1405. + Lophocorys, 1420. + acanthocephala, 1421. + astrocephala, 1421. + bicornis, 1421. + brevicornis, 1422. + quadricornis, 1422. + Lophocyrtis, 1410. + biaurita, 1411. + coronata, 1411. + holothuria, 1410. + stephanophora, 1410. + synapta, 1411. + Lophophaena, 1303. + _amphora_, 1302. + _apiculata_, 1303. + _capito_, 1204. + circumtexta, 1304. + _cornuta_, 1398. + echinocephala, 1304. + galea, 1303. + galeata, 1204. + _larvata_, 1282. + liothorax, 1304. + _lynx_, 1303. + _obtusa_, 1308. + radians, 1303. + Lophophaenoma, 1304. + Lophophaenula, 1303. + LOPHOSPYRIDA, 1078. + Lophospyris, 1066. + acuminata, 1080. + comosa, 1071. + dipodiacus, 1080. + Lychnasparium, 839. + LYCHNASPIDA, 835. + Lychnaspidium, 842. + _haliommidium_, 842. + Lychnaspis, 829. + capillaris, 839. + cataplasta, 843. + echinoides, 842. + giltschii, 839. + haliommidium, 842. + longissima, 841. + maxima, 839. + minima, 841. + polyancistra, 840. + rabbeana, 842. + rottenburgii, 841. + serrata, 840. + undulata, 841. + wagenschieberi, 840. + Lychnocanella, 1224. + Lychnocanissa, 1225. + Lychnocanium, 1224. + _arabicum_, 1198. + _campanella_, 1331. + carinatum, 1226. + clavigerum, 1230. + continuum, 1225. + crassipes, 1230. + cypselus, 1229. + _depressum_, 1331. + falciferum, 1207. + favosum, 1225. + fenestratum, 1228. + fortipes, 1227. + _hamosum_, 1199. + hirundo, 1227. + lanterna, 1224. + _lucerna_, 1199. + nodosum, 1225. + ovatum, 1229. + _praetextum_, 1330. + pudicum, 1230. + pyriforme, 1225. + sigmopodium, 1228. + _tetrapodium_, 1228. + tribulus, 1226. + trichopus, 1228. + _tridentatum_, 1199. + tripodium, 1229. + tuberosum, 1227. + _turgidum_, 1319. + ventricosum, 1226. + Lychnocanoma, 1229. + Lychnodictyum, 1230. + challengeri, 1231. + sethopodium, 1231. + scaphopodium, 1231. + wyvillei, 1231. + Lychnosphaera, 276. + regina, 277. + _rhizoplegma_, 276. + + Mazosphaera, 108. + apicata, 109. + hippotis, 108. + _inflata_, 101. + laevis, 109. + lagotis, 108. + Medusetta, 1667. + codonium, 1668. + craspedota, 1669. + minima, 1668. + quadrigata, 1668. + spiralis, 1669. + tetranema, 1669. + tiara, 1668. + MEDUSETTIDA, 1663. + Melitomma, 76. + formosum, 231. + _melittosphaera_, 73. + Melittosphaera, 72. + Merosiphonia, 106. + MEROTRYPASTA, 5. + Mesocena, 1554. + annulus, 1555. + _binonaria_, 1557. + bisoctona, 1557. + circulus, 1555. + _crenulata_, 1555. + diodon, 1555. + elliptica, 1556. + _heptagona_, 1557. + hexagona, 1556. + _nonaria_, 1557. + octogona, 1557. + _octoradiata_, 1557. + pentagona, 1556. + quadrangula, 1556. + _quaternaria_, 1556. + _senaria_, 1556. + _septenaria_, 1556. + stellata, 1557. + triangula, 1555. + Microcubus, 997. + amphispyris, 999. + cornutus, 999. + dodecastoma, 998. + pentacircus, 998. + quadrupes, 998. + zonarius, 998. + Micromelissa, 1205. + apis, 1235. + bombus, 1235. + microptera, 1236. + ventricosa, 1236. + vespa, 1235. + Mitrocalpis, 1188. + palliata, 1188. + MONOCYRTIDA, 1133. + MONODICTYA, 1126. + MONOPRUNIDA, 288. + MONOPYLARIA, 889. + MONOPYLEA, 889. + MONOSPHAERIDA, 52. + MONOSTEPHIDA, 937. + Monostephus, 940. + Monozonium, 633. + alatum, 633. + amphistylum, 634. + hartingii, 1763. + pleurostylum, 634. + primordiale, 633. + staurostylum, 634. + Myelastrella, 553. + Myelastromma, 553. + Myelastrum, 553. + anomalum, 556. + ciliatum, 555. + decaceros, 554. + dodecaceros, 554. + farfalla, 554. + giganteum, 555. + heteropterum, 553. + lobatum, 555. + medullare, 553. + octocorne, 553. + papilio, 554. + rotula, 555. + spinale, 553. + _Myxobrachia_, 22. + _cienkowskii_, 1763. + _pluteus_, 22. + _rhopalum_, 22. + + Nassella, 898. + nassiterna, 898. + thalassicolla, 898. + NASSELLARIA, 889. + NASSELLIDA, 896. + NASSOIDEA, 895. + Nephrodictyum, 1101. + NEPHROSPYRIDA, 1099. + Nephrospyris, 1100. + cordata, 1102. + nephridium, 1101. + paradictyum, 1102. + paradoxa, 1102. + phaseolus, 1101. + renilla, 1101. + + Octalacorys, 1373. + Octodendron, 279. + araucaria, 280. + arboretum, 281. + contortum, 281. + cubocentron, 279. + pinetum, 280. + spathillatum, 280. + spirale, 279. + verticillatum, 281. + Octopelta, 855. + cultella, 855. + furcella, 856. + scutella, 856. + Octophormis, 1245. + Octopyle, 650. + amphistyle, 651. + decastyle, 654. + euryzona, 652. + hexastyle, 653. + obtecta, 653. + octostyle, 653. + ovulina, 650. + quadrata, 650. + sexangulata, 653. + staurostyle, 651. + stenozona, 652. + subglobosa, 651. + tetraptera, 652. + tetrastyle, 652. + transversaria, 651. + Octotympanum, 999. + arborescens, 1000. + cervicorne, 1000. + octonarium, 1000. + octospinum, 1000. + Odontosphaera, 102. + cyrtodon, 102. + monodon, 102. + OMMACAMPIDA, 392. + Ommatartus, 396. + amphicanna, 396. + amphisiphon, 396. + amphiobolus, 396. + Ommathymenium, 520. + OMMATIDA, 51. + Ommatocampe, 393. + amphilonche, 395. + annulata, 393. + chaetopodum, 395. + erucaeformis, 394. + increscens, 393. + nereis, 394. + polyarthra, 393. + _profundissima_, 380. + _setosa_, 381. + Ommatocyrtis, 366. + OMMATODISCIDA, 500. + Ommatodiscus, 500. + circularis, 501. + decipiens, 500. + fragilis, 502. + haeckelii, 501. + laevigatus, 502. + stoehrii, 501. + _Ommatogramma_, 519. + _navicularis_, 519. + _Ommatospyris_, 363. + _apicata_, 371. + _coscinoides_, 363. + _entomocora_, 367. + _ethmaria_, 363. + _loeevis_, 361. + _penicillata_, 370. + _profunda_, 365. + _virginea_, 363. + Orodendrum, 1598. + Orodictyum, 1601. + Orona, 1594. + crassissima, 1594. + maxima, 1594. + robusta, 1594. + ORONIDA, 1593. + Oronium, 1594. + Orophasparium, 818. + Orophaspidium, 818. + Orophaspis, 817. + astrolonche, 818. + diporaspis, 819. + furcata, 818. + gladiata, 818. + ramosa, 818. + tessaraspis, 819. + Oroplegma, 1600. + diplosphaera, 1600. + giganteum, 1601. + spinulosum, 1600. + spongiosum, 1601. + velatum, 1600. + Oroplegmium, 1600. + Oroscena, 1597. + baerii, 1598. + cuvieri, 1598. + darwinii, 1599. + duncanii, 1599. + gegenbauri, 1597. + huxleyi, 1599. + muelleri, 1598. + wolffii, 1598. + OROSCENIDA, 1593. + Oroscenium, 1597. + Orosphaera, 1594. + arborescens, 1597. + clavigera, 1596. + confluens, 1596. + foveolata, 1595. + furcata, 1596. + fusigera, 1595. + hastigera, 1595. + horrida, 1596. + ramigera, 1596. + spinigera, 1595. + serpentina, 1595. + OROSPHAERIDA, 1590. + Orothamnus, 1596. + _arborescens_, 1597. + Otosphaera, 116. + auriculata, 116. + polymorpha, 116. + + PANACANTHA, 715. + Panarium, 388. + annularium, 389. + artophorum, 389. + facettarium, 388. + pipettarium, 389. + tubularium, 390. + Panartella, 377. + PANARTIDA, 375. + Panartissa, 379. + Panartoma, 381. + Panartura, 381. + Panartus, 376. + amphiconus, 379. + diploconus, 379. + fusiformis, 379. + pluteus, 382. + profundissimus, 380. + quadriceps, 380. + quadrigeminus, 381. + quadrijugus, 380. + setosus, 381. + spinosus, 381. + tetracolus, 377. + tetrameres, 378. + tetraphalangus, 378. + tetraplus, 377. + tetrathalamus, 378. + Panicium, 385. + amphacanthum, 385. + amphistylus, 385. + coronatum, 386. + scoparium, 385. + PANSOLENIA, 1521. + Pantopelta, 855. + icosaspis, 855. + PARADICTYIDA, 1099. + Paradictyum, 1102. + paradoxum, 1102. + Parastephanus, 1008. + asymmetricus, 1008. + circularis, 1008. + dispar, 1009. + quadrispinus, 1008. + PARASTEPHIDA, 987. + PARATYMPANIDA, 1004. + Paratympanum, 1005. + decastylum, 1005. + hexastylum, 1005. + octostylum, 1005. + Patagospyris, 1087. + anthocyrtis, 1088. + confluens, 1088. + lanceolata, 1088. + stiligera, 1088. + PELTOPHRACTA, 803. + Pentactura, 479. + astropecten, 479. + pentactis, 479. + Pentalacorys, 1371. + Pentalastrum, 556. + asteracanthion, 556. + astropecten, 556. + cometa, 557. + ophidiaster, 557. + Pentaphormis, 1244. + _Pentaplegma_, 930. + _decacantha_, 930. + Pentasolenia, 113. + PENTASPYRIDA, 1052. + Pentaspyris, 1054. + isacantha, 1055. + pentacantha, 1054. + Pentinastrum, 557. + asteriscus, 557. + goniaster, 558. + Pentoniscus, 488. + Pentophiastrum, 558. + caudatum, 559. + dicranastrum, 558. + forcipatum, 559. + Periarachnium, 1297. + periplectum, 1297. + Perichlamydium, 499. + accrescens, 499. + _aequale_, 515. + _asteriscus_, 514. + _limbatum_, 514. + praetextum, 499. + saturnus, 499. + spirale, 499. + _spongiosum_, 516. + _venustum_, 515. + Peridarium, 1153. + Peridium, 1153. + alatum, 1155. + cervinum, 1155. + curvipes, 1154. + lasanum, 1154. + palmipes, 1154. + papillatum, 1154. + spinipes, 1154. + Peripanarium, 390. + cenoconicum, 390. + cenocylindricum, 391. + Peripanartus, 382. + amphiconus, 383. + _amphicorona_, 387. + atractus, 384. + cylindrus, 384. + laevigatus, 383. + palliatus, 382. + Peripanicium, 386. + amphicorona, 387. + amphixiphus, 386. + coronarium, 387. + Periphaena, 426. + cincta, 426. + decora, 426. + statoblastus, 426. + Periplecta, 926. + cortina, 926. + monocyrtis, 927. + pteroscenium, 926. + PERIPYLARIA, 6. + PERIPYLEA, 6. + Peripyramis, 1162. + cirumtexta, 1162. + spongiosa, 1162. + Perispira, 494. + _perforata_, 495. + _radiata_, 495. + _Perispongidium_, 498. + _irregulare_, 498. + PERISPYRIDA, 1095. + Perispyris, 1098. + bicincta, 1099. + lentellipsis, 1099. + spongiosa, 1099. + Perizona, 427. + scutella, 427. + pterygota, 427. + Peromelissa, 1236. + calva, 1237. + capito, 1237. + phalacra, 1236. + psilocrana, 1237. + Petalospyrantha, 1060. + Petalospyrella, 1060. + Petalospyris, 1059. + anthemis, 1062. + anthocyrtoides, 1090. + _arachnoides_, 1065. + argiscus, 1062. + bellidiastrum, 1063. + _carinata_, 1074. + _clathrus_, 1049. + _confluens_, 1088. + corona, 1061. + _diaboliscus_, 1065. + dictyocubus, 1063. + dinoceras, 1063. + eupetala, 1061. + _flabellum_, 1174. + floscula, 1060. + foveolata, 1060. + furcata, 1064. + lobata, 1064. + novena, 1062. + _ocellata_, 1174. + octopus, 1061. + _ophirensis_, 1048. + papillata, 1063. + _pentas_, 1070. + platyacantha, 1060. + _radicata_, 1051. + _seminulum_, 1046. + _spinosa_, 1048. + tessaromma, 1062. + triomma, 1060. + Petalospyrissa, 1061. + Petalospyromma, 1062. + PHACODISCARIA, 409. + PHACODISCIDA, 419. + Phacodiscus, 424. + clypeus, 425. + echiniscus, 425. + grandis, 425. + lentiformis, 425. + rotula, 424. + Phacostaurium, 435. + Phacostaurus, 435. + magnificus, 436. + oceanidum, 435. + _pyramidalis_, 465. + quadrigatus, 436. + Phacostylium, 430. + Phacostylus, 430. + amphipyramis, 431. + amphistylus, 430. + amphixiphos, 430. + caudatus, 431. + maximus, 431. + PHAENOCALPIDA, 1157. + Phaenocalpis, 1173. + carinata, 1174. + flabellum, 1174. + ocellata, 1174. + petalospyris, 1173. + Phaenoscenium, 1174. + cladopodium, 1175. + hexapodium, 1175. + polypodium, 1175. + Phaeocolla, 1544. + primordialis, 1544. + PHAEOCONCHIA, 1710. + PHAEOCOSCINA, 1537. + PHAEOCYSTINA, 1542. + PHAEODARIA, 1521. + Phaeodina, 1545. + cannopylea, 1546. + tripylea, 1545. + PHAEODINIDA, 1543. + PHAEOGROMIA, 1642. + PHAEOSPHAERIA, 1590. + Pharyngella, 1662. + gastraea, 1662. + gastrula, 1662. + invaginata, 1662. + monoceros, 1662. + PHARYNGELLIDA, 1660. + Pharyngosphaera, 98. + stomodaea, 98. + Phatnacantha, 765. + icosaspis, 765. + tessaraspis, 765. + Phatnasparium, 868. + PHATNASPIDA, 861. + Phatnaspidium, 871. + Phatnaspis, 870. + coscinoides, 870. + cristata, 869. + ensiformis, 869. + fenestrata, 869. + haliommidium, 871. + lacunaria, 869. + loculata, 869. + muelleri, 871. + orthopora, 870, + polypora, 870. + quadratura, 871. + tabulata, 871. + Phatnasplenium, 870. + Phlebarachnium, 1295. + _facetum_, 1296. + _setosum_, 1296. + _venosum_, 1297. + Phoenicosphaera, 75. + Phormobotrys, 1124. + cannothalamia, 1125. + hexathalamia, 1125. + pentathalamia, 1124. + polythalamia, 1125. + trithalamia, 1124. + Phormocampe, 1456. + campanula, 1456. + conus, 1458. + eucalyptra, 1457. + lamprocyclas, 1457. + metalis, 1457. + mitra, 1458. + PHORMOCAMPIDA, 1453. + PHORMOCYRTIDA, 1365. + Phormocyrtis, 1368. + carinata, 1368. + costata, 1369. + embolum, 1369. + fastosa, 1369. + longicornis, 1370. + quadrata, 1369. + Phormosphaera, 61. + PHORMOSPYRIDA, 1084. + Phormospyris, 1076. + tricostata, 1087. + tridentata, 1087. + trifoliata, 1087. + PHORTICIDA, 708. + Phorticium, 709. + abnorme, 710. + deforme, 710. + pylonium, 709. + spironium, 709. + Phortolarcus, 710. + Phortopyle, 709. + Phractacantha, 755. + bifurca, 755. + bipennis, 755. + PHRACTACANTHIDA, 753. + Phractasparium, 808. + PHRACTASPIDA, 808. + Phractaspidium, 810. + Phractaspis, 809. + bipennis, 809. + cataphracta, 810. + complanata, 809. + condylophora, 809. + constricta, 810. + prototypus, 809. + Phractasplenium, 809. + bipenne, 809. + Phractopelta, 852. + aspidomma, 854. + dorataspis, 852. + diporaspis, 852. + dyadopora, 852. + haliomma, 854. + hexadopora, 853. + hystrix, 854. + octadopora, 853. + tessaraspis, 853. + tessaromma, 854. + tetradopora, 853. + PHRACTOPELTIDA, 847. + Phrenocodon, 1433. + clathrostomium, 1434. + diaphragma, 1434. + Phyllostaurus, 744. + Physematium, 34. + atlanticum, 35. + muelleri, 35. + PILOCYRTIDA, 1129. + Pipetta, 337. + conus, 338. + fusus, 337. + salpinx, 338. + tuba, 337. + Pipettaria, 339. + fusaria, 339. + tubaria, 339. + Pipettella, 304. + elongata, 305. + fusiformis, 304. + prismatica, 305. + tubulosa, 305. + Pityomma, 259. + drymodes, 260. + piniferum, 260. + scoparium, 259. + Plagiacantha, 909. + abietina, 910. + arachnoides, 910. + dodecantha, 910. + elatine, 911. + furcata, 910. + verticillata, 910. + PLAGIACANTHIDA, 898. + Plagiocarpa, 914. + procortina, 914. + procyrtella, 914. + PLAGONIDA, 906. + Plagonidium, 913. + bigeminum, 913. + quadrigeminum, 914. + Plagoniscus, 912. + cortinaris, 913. + euscenium, 912. + nassellaris, 913. + tripodiscus, 912. + Plagonium, 916. + arborescens, 917. + distriactis, 917. + lampoxanthium, 907. + sphaerozoum, 916. + trigeminum, 917. + _Platybursa_, 1051. + _compressa_, 1051. + _Platycryphalus_, 1298. + _sethodiscus_, 1298. + PLECTANIDA, 919. + Plectaniscus, 924. + archiscenium, 925. + cladoscenium, 925. + clathrocorys, 925. + cortiniscus, 925. + tripodiscus, 925. + Plectanium, 928. + ovodimare, 928. + sphaerozoum, 928. + trigeminum, 928. + PLECTELLARIA, 895. + PLECTIDA, 898. + Plectocoronis, 979. + anacantha, 979. + pentacantha, 979. + triacantha, 979. + PLECTOIDEA, 898. + Plectophora, 922. + arachnoides, 922. + novena, 923. + pyramidalis, 923. + triomma, 922. + Plectopyramis, 1256. + dodecomma, 1258. + fenestrata, 1259. + furcata, 1259. + heteromma, 1259. + hexapleura, 1257. + lagena, 1260. + magnifica, 1257. + polygonomma, 1258. + polypleura, 1260. + quadratomma, 1258. + serrata, 1259. + _spongiosa_, 1261. + trapezomma, 1258. + Plegmosphaera, 87. + coelopila, 88. + entodictyon, 88. + exodictyon, 89. + leptodictyon, 89. + leptoplegma, 89. + maxima, 88. + pachypila, 88. + pachyplegma, 89. + _polybrocha_, 930. + PLEGMOSPHAERIDA, 86. + Pleurasparium, 811. + Pleuraspidium, 812. + Pleuraspis, 811. + amphithecta, 811. + costata, 812. + horrida, 811. + pyramidalis, 812. + ramosa, 812. + Pleuropodium, 1336. + charybdeum, 1336. + cortina, 1336. + Podocampe, 1445. + conica, 1446. + cornuta, 1446. + trictenota, 1446. + tripodiscus, 1446. + PODOCAMPIDA, 1435. + Podocoronis, 980. + cortiniscus, 981. + dipodiscus, 980. + hexapodiscus, 982. + petalospyris, 982. + polypodiscus, 982. + tetrapodiscus, 981. + toxarium, 980. + tripodiscus, 981. + Podocyrtarium, 1337. + Podocyrtecium, 1339. + PODOCYRTIDA, 1314. + Podocyrtidium, 1344. + Podocyrtis, 1337. + _aculeata_, 1373. + _aegles_, 1391. + _aerostatica_, 1252. + _amphiacantha_, 1344. + ampla, 1348. + argulus, 1344. + argus, 1346. + attenuata, 1338. + _bicornis_, 1349. + brevipes, 1340. + bromia, 1349. + _campanella_, 1331. + centriscus, 1341. + _charybdea_, 1336. + collaris, 1340. + conica, 1338. + conulus, 1339. + corythaeola, 1339. + costata, 1345. + _cothurnata_, 1353. + cristata, 1342. + _dipus_, 1349. + divergens, 1340. + _domina_, 1387. + ehrenbergii, 1344. + euceros, 1342. + eulophos, 1346. + favosa, 1346. + floribunda, 1347. + flosculata, 1341. + fusiformis, 1346. + hexagonalis, 1343. + lithoconus, 1348. + lyaea, 1348. + magnifica, 1341. + _micracantha_, 1761. + mitra, 1345. + mitrella, 1345. + nana, 1348. + ovata, 1343. + papalis, 1344. + _parvipes_, 1371. + pedicellaria, 1347. + _pentacantha_, 1371. + princeps, 1342. + prismatica, 1340. + _puella_, 1387. + _radicata_, 1351. + _rhizodon_, 1351. + scaphopodia, 1347. + schomburgkii, 1343. + sinuosa, 1347. + sphaerogaster, 1349. + _spinosa_, 1169. + surena, 1339. + tetracantha, 1371. + thyrsoceras, 1338. + triacantha, 1350. + tridactyla, 1339. + tripodiscus, 1338. + tripus, 1349. + urceolata, 1343. + ventricosa, 1347. + Podocyrtonium, 1347. + Polyalacorys, 1374. + POLYCYRTIDA, 1103. + POLYCYSTINA, 1. + Polyplagia, 917, + duodenaria, 918. + novenaria, 918. + octonaria, 918. + septenaria, 918. + viminaria, 919. + POLYPLAGIDA, 917. + Polyplecta, 929. + decacantha, 930. + dumetum, 930. + enneacantha, 929. + heptacantha, 928. + polybrocha, 930. + POLYPLECTIDA, 929. + Polypleuris, 1260. + Polypetta, 1676. + alveolata, 1676. + mammillata, 1677. + polynema, 1676. + tabulata, 1677. + POLYPRUNIDA, 288. + Polysolenia, 113. + _setosa_, 100. + POLYSPHAERIDA, 52. + POLYSPYRIDA, 1059. + Polystichia, 1762. + ehrenbergii, 1762. + haeckelii, 1762. + muelleri, 1762. + Porcupinia, 1663. + aculeata, 1663. + cordiformis, 1663. + Porocapsa, 800. + coronodon, 801. + murrayana, 800. + octodon, 800. + tetrodon, 800. + POROCAPSIDA, 799. + PORODISCIDA, 481. + Porodiscus, 491. + bispiralis, 497. + bilix, 496. + centrospira, 495. + concentricus, 492. + deformis, 498. + duplex, 497. + ellipticus, 494. + flustrella, 493. + helicoides, 496. + heterocyclus, 494. + irregularis, 498. + macroporus, 493. + microporus, 493. + operculina, 496. + orbiculatus, 492. + perispira, 495. + quadrigatus, 494. + radiatus, 495. + semispiralis, 497. + sorites, 493. + spiralis, 496. + _Porospathis_, 1677. + _mammillata_, 1677. + _tubulata_, 1677. + Porosphaera, 67. + Prismatium, 1009. + tripleurum, 1010. + tripodium, 1009. + Pristacantha, 765. + dodecodon, 766. + octodon, 765. + polyodon, 766. + Pristodiscus, 418. + Procyttarium, 13. + _primordiale_, 13. + PROTYMPANIDA, 991. + Protympanium, 991. + amphipodium, 992. + primordiale, 991. + trissocircus, 992. + Prunocarpus, 316. + artocarpium, 316. + datura, 316. + melocactus, 317. + sparganium, 316. + PRUNOIDEA, 284. + PRUNOPHRACTA, 859. + Prunosphaera, 74. + Prunulum, 313. + amygdalum, 313. + cerasum, 313. + coccymelium, 313. + crenatum, 314. + fenestratum, 315. + frugulum, 313. + persicum, 314. + pyrenium, 315. + triplex, 314. + Pseudocubus, 1010. + hexapylus, 1011. + obeliscus, 1010. + octostylus, 1010. + Psilomelissa, 1208. + calvata, 1209. + galeata, 1208. + hertwigii, 1209. + phalacra, 1208. + sphaerocephala, 1209. + Pteractis, 535. + _elegans_, 535. + Pterocanarium, 1329. + Pterocanidium, 1332. + Pterocanium, 1328. + _barbadense_, 1318. + _bibrachiatum_, 1327. + bicorne, 1332. + _bombus_, 1443. + campanella, 1331. + _charybdeum_, 1336. + contiguum, 1330. + _davisianum_, 1437. + depressum, 1331. + eucolpum, 1332. + _falciferum_, 1317. + gravidum, 1329. + orcinum, 1329. + praetextum, 1330. + proserpinae, 1329. + pyramis, 1330. + _sabae_, 1317. + _sphinx_, 1443. + tricolpum, 1331. + trilobum, 1333. + virgineum, 1330. + Pterocodon, 1333. + _apis_, 1318. + campana, 1333. + _campanella_, 1223. + _davisianus_, 1437. + favosus, 1334. + ornatus, 1333. + Pterocorys, 1316. + apis, 1318. + aquila, 1317. + barbadensis, 1318. + campanula, 1316. + carinata, 1316. + columba, 1317. + falcifera, 1317. + hirundo, 1318. + macroptera, 1321. + melitta, 1319. + pipetta, 1320. + prismatica, 1320. + rhinoceros, 1320. + sabae, 1317. + tricornis, 1320. + tubulosa, 1319. + turgida, 1319. + zittelii, 1321. + Pterocorythium, 1320. + _Pterocyrtidium_, 1316. + _barbadense_, 1318. + _zittelii_, 1321. + Pteropilium, 1326. + bombus, 1443. + clathrocanium, 1327. + eques, 1327. + hoplites, 1327. + pyramis, 1443. + sphinx, 1443. + stratiotes, 1326. + Pteroscenium, 1151. + arcadophorum, 1152. + arcuatum, 1152. + macropodium, 1153. + pinnatum, 1152. + spinulosum, 1152. + tripocolpum, 1153. + _Pterosyringium_, 1319. + _tubulosum_, 1319. + PYLOBOTRYIDA, 1119. + Pylobotrys, 1121. + cerebralis, 1122. + fontinalis, 1122. + putealis, 1121. + PYLODISCIDA, 561. + Pylodiscus, 570. + cardiopylus, 571. + nephropylus, 571. + sexangularis, 570. + triangularis, 570. + Pylolena, 568. + inermis, 568. + armata, 568. + PYLONIDA, 628. + Pylonium, 654. + circozonium, 654. + hexazonium, 655. + nephropylium, 655. + octacanthum, 655. + quadricorne, 655. + stenozonium, 656. + Pylospira, 697. + tetrapyle, 698. + octopyle, 698. + cymbium, 698. + Pylospirema, 697. + PYLOSPYRIDA, 1078. + Pylospyris, 1083. + canariensis, 1084. + denticulata, 1083. + trinacria, 1083. + Pylospironium, 698. + Pylozonium, 659. + novemcinctum, 659. + octacanthum, 660. + + Quadriloncharium, 776. + QUADRILONCHIDA, 766. + Quadrilonchidium, 777. + Quadrilonche, 776. + mesostaura, 777. + platystaura, 777. + telostaura, 777. + tetrastaura, 776. + + Rhaphidocapsa, 211. + Rhaphidococcus, 210. + _acufer_, 211. + _lurianensis_, 1762. + _simplex_, 216. + Rhaphidodrymus, 214. + Rhaphidosphaera, 214. + _reticulata_, 217. + Rhaphidozoum, 46. + acuferum, 46. + arachnoides, 47. + ascensionis, 48. + asperum, 47. + australe, 48. + capense, 48. + neapolitanum, 47. + pacificum, 46. + pandora, 49. + patagonicum, 48. + pelagicum, 46. + polymorphum, 49. + Rhizoplegma, 275. + lychnosphaera, 275. + polyacanthum, 275. + radicatum, 276. + spirale, 275. + trigonacanthum, 276. + Rhizosphaera, 283. + leptomita, 284. + serrata, 284. + trigonacantha, 283. + Rhodosphaera, 83. + hexagonia, 83. + melitomma, 83. + palliata, 83. + pentaphylla, 83. + RHODOSPYRIDA, 1087. + Rhodospyris, 1088. + triceros, 1089. + tricornis, 1089. + Rhopalastrella, 526. + Rhopalastromma, 528. + Rhopalastrum, 526. + arcticum, 529. + _bandaicum_, 525. + clavatum, 528. + hexaceros, 529. + _hexagonum_, 525. + irregulare, 528. + lagenosum, 527. + malleus, 527. + martellum, 528. + pistillum, 527. + triceros, 529. + _trispinosum_, 525. + truncatum, 526. + ypsilinum, 528. + Rhopalatractus, 1360. + fenestratus, 1361. + foveolatus, 1361. + fusiformis, 1361. + pentacanthus, 1361. + Rhopalocanium, 1359. + cortinium, 1359. + delphicum, 1360. + lasanum, 1359. + ornatum, 1359. + _prismaticum_, 1357. + pythia, 1360. + Rhopalodictyum, 589. + abyssorum, 589. + bifidum, 590. + curvatum, 591. + elongatum, 591. + subacutum, 590. + truncatum, 589. + zittelii, 590. + + Sagena, 1605. + crucifera, 1606. + pertusa, 1606. + ternaria, 1606. + triangula, 1606. + SAGENIDA, 1605. + Sagenoscena, 1610. + coronata, 1611. + cruciata, 1611. + ornata, 1610. + penicillata, 1611. + spathillata, 1611. + stellata, 1610. + SAGMARIDA, 1612. + Sagmarium, 1612. + plegmosphaerium, 1612. + spongodictyum, 1612. + trigonizon, 1612. + Sagmidium, 1613. + crucicorne, 1613. + multicorne, 1614. + quadricorne, 1614. + tricorne, 1613. + unicorne, 1613. + Sagoplegma, 1614. + pyramidophora, 1614. + scenophora, 1615. + Sagoscena, 1608. + castra, 1608. + cruciarium, 1609. + debilis, 1609. + fragilis, 1610. + gracilis, 1609. + pellorium, 1609. + praetorium, 1609. + tentorium, 1608. + Sagosphaera, 1607. + coronilla, 1608. + furcilla, 1607. + penicilla, 1607. + trigonilla, 1607. + verticilla, 1607. + SAGOSPHAERIDA, 1601. + Saturnalis, 131. + annularis, 132. + circoideus, 132. + circularis, 131. + cyclus, 132. + rotula, 133. + trochoides, 132. + Saturnalium, 132. + Saturninus, 146. + triplex, 146. + Saturnulus, 141. + annulus, 141. + circulus, 141. + ellipticus, 141. + planetes, 142. + _Schizomma_, 645. + _quadrilobum_, 645. + SEMANTIDA, 953. + Semantidium, 960. + haeckelii, 961. + hexastoma, 960. + sexangulum, 960. + signatorium, 961. + Semantis, 956. + biforis, 956. + dipyla, 957. + distephanus, 957. + distoma, 957. + sigillum, 957. + spinescens, 958. + SEMANTISCIDA, 956. + Semantiscus, 966. + hexapodius, 966, + hexapylus, 967. + hexaspyris, 966. + Semantrum, 958. + buetschlii, 959. + muelleri, 959. + quadrifore, 958. + signarium, 960. + sphragisma, 959. + tetrapylum, 959. + tetrastoma, 959. + Sepalospyris, 1081. + platyphylla, 1081. + polyphylla, 1081. + Sethamphora, 1249. + aerostatica, 1252. + ampulla, 1251. + costata, 1251. + dodecapleura, 1250. + enneapleura, 1250. + favosa, 1252. + hexapleura, 1250. + microstoma, 1252. + mongolfieri, 1251. + serrata, 1251. + Sethocapsa, 1310. + ampulla, 1311. + bulla, 1311. + lagena, 1310. + macroceros, 1310. + nidus, 1311. + pyriformis, 1310. + staurocephala, 1311. + SETHOCAPSIDA, 1309. + Sethocephalus, 1298. + eucecryphalus, 1298. + platycryphalus, 1298. + Sethochytris, 1239. + barbadensis, 1239. + pyramis, 1240. + triangula, 1240. + triconiscus, 1239. + Sethoconus, 1290. + ampliatus, 1291. + anthocyrtis, 1296. + bimarginatus, 1295. + cervus, 1292. + clathratus, 1295. + cucullaris, 1290. + facetus, 1296. + gracilis, 1295. + hexagonalis, 1293. + larvatus, 1282. + longisetus, 1294. + lophophaena, 1292. + mitra, 1291. + nassa, 1293. + orthoceras, 1294. + pileus, 1291. + profundus, 1294. + rayianus, 1291. + setosus, 1296. + tabulatus, 1293. + trichostylus, 1294. + trochus, 1290. + venosus, 1297. + verrucosus, 1293. + virgultus, 1296. + SETHOCORIDA, 1289. + Sethocorys, 1301. + achillis, 1301. + ajacis, 1302. + amphora, 1302. + armadillo, 1302. + odysseus, 1302. + patrocli, 1301. + SETHOCYRTIDA, 1288. + Sethocyrtis, 1298. + agamemnonis, 1300. + cancrina, 1292. + cassis, 1301. + diomedis, 1292. + menelai, 1299. + oxycephalis, 1299. + pleuracantha, 1300. + subacuta, 1300. + SETHODISCIDA, 422. + Sethodiscus, 422. + cristatus, 424. + echinatus, 424. + lenticula, 423. + macrococcus, 423. + macroporus, 422. + micrococcus, 423. + microporus, 422. + phacoides, 422. + radians, 423. + Sethomelissa, 1207. + hymenoptera, 1238. + Sethopera, 1232. + lagena, 1233. + oceania, 1232. + pyrum, 1232. + tricostata, 1232. + SETHOPERIDA, 1232. + Sethophaena, 1285. + enneaptera, 1286. + hexaptera, 1286. + polyptera, 1286. + tetraptera, 1285. + SETHOPHAENIDA, 1285. + SETHOPHORMIDA, 1143. + Sethophormis, 1243. + arachnium, 1247. + asteriscus, 1244. + astrodiscus, 1244. + aurelia, 1248. + cruciata, 1243. + dodecaster, 1248. + enneactis, 1247. + enneastrum, 1246. + eupilium, 1247. + floscula, 1249. + hexagonalis, 1245. + hexalactis, 1245. + leptopilium, 1249. + leptoscenium, 1249. + medusa, 1244. + octalactis, 1245. + pentalactis, 1244. + rotula, 1246. + triloba, 1246. + umbrella, 1248. + SETHOPILIDA, 1195. + Sethopilium, 1202. + cyrtopus, 1202. + macropus, 1203. + orthopus, 1202. + Sethopyramis, 1253. + bicornis, 1256. + cyclomma, 1255. + dodecalactis, 1256. + enneactis, 1254. + _eupilium_, 1247. + hexagonalis, 1255. + hexalactis, 1253. + maxima, 1256. + quadrata, 1254. + quadratella, 1254. + scalaris, 1253. + spinosa, 1255. + trapezoides, 1254. + Sethornithium, 1356. + dictyopterum, 1356. + Sethosphaera, 71. + entosiphonia, 71. + entosolenia, 71. + _rhodococcus_, 237. + Sethostaurium, 438. + Sethostaurus, 433. + conostaurus, 433. + coronatus, 434. + cruciatus, 434. + gigas, 435. + orthostaurus, 433. + recurvatus, 434. + rhombostaurus, 434. + Sethostylium, 428. + Sethostylus, 429. + dentatus, 429. + dicylindrus, 428. + distyliscus, 428. + _endostylus_, 413. + hastatus, 429. + serratus, 429. + spicatus, 430. + Siphocampe, 1490. + annulosa, 1500. + caminosa, 1500. + erucosa, 1500. + quadrantalis, 1501. + spiralis, 1501. + tubulosa, 1500. + Siphocampium, 1501. + Siphocampula, 1499. + _Siphonaspis_, 823. + _cristata_, 823. + Siphonosphaera, 104. + chonophora, 107. + conifera, 106. + cyathina, 105. + fragilis, 106. + infundibulum, 105. + macrosiphonia, 107. + marginata, 104. + pansiphonia, 104. + patinaria, 105. + pipetta, 108. + polysiphonia, 106. + serpula, 107. + socialis, 106. + tubulosa, 105. + Solenosphaera, 112. + amalthea, 115. + ascensionis, 115. + cornucopiae, 115. + megalactis, 114. + pandora, 113. + serpentina, 114. + variabilis, 113. + venosa, 114. + Soreuma, 713. + acervulina, 714. + acinosum, 713. + irregulare, 713. + setosum, 714. + spinosum, 714. + subglobosum, 713. + SOREUMIDA, 712. + Sorolarcus, 715. + larnacillifer, 715. + tetrapylifer, 715. + terminalis, 715. + SPHAERELLARIA, 49. + SPHAERIDEA, 50. + Sphaerocapsa, 798. + cruciata, 798. + dentata, 798. + quadrata, 798. + pavimentata, 798. + SPHAEROCAPSIDA, 795. + SPHAEROIDEA, 50. + SPHAEROPHRACTA, 795. + Sphaerospyris, 1099. + globosa, 1100. + quadriforis, 1100. + sphaera, 1100. + SPHAEROSTYLIDA, 133. + Sphaerostylus, 138. + clio, 139. + cottus, 140. + diadema, 139, + flexuosus, 138. + hippocampus, 139. + liostylus, 138. + ophidium, 140. + trigla, 140. + SPHAEROZOIDA, 38. + Sphaerozoum, 40. + _acuferum_, 46. + alveolatum, 43. + araucaria, 44. + arborescens, 44. + armatum, 43. + _atlanticum_, 40. + _bicellulare_, 25. + _bifurcum_, 33. + circumtextum, 45. + furcatum, 42. + furculosum, 42. + _fuscum_, 43. + geminatum, 45. + hamatum, 41. + hexactinium, 41. + _inerme_, 25. + _italicum_, 40. + medusinum, 41. + _neapolitanum_, 47. + octoceras, 44. + _orientale_, 1763. + ovodimare, 42. + _pelagicum_, 28. + punctatum, 43. + _punctatum_, 42. + quadrigeminum, 44. + _sanderi_, 1763. + _spinulosum_, 40. + stellatum, 45. + triactinium, 41. + trigeminum, 43. + variabile, 45. + verticillatum, 44. + Spiremarium, 692. + Spirema, 692. + diplospira, 693. + flustrella, 692. + lentellipsis, 692. + melonia, 692. + subglobosum, 693. + SPIREMIDA, 691. + Spiremidium, 693. + Spirocampe, 1511. + allospira, 1511. + callispira, 1511. + polyspira, 1511. + Spirocyrtidium, 1509. + Spirocyrtis, 1508. + cornutella, 1509. + diplospira, 1510. + hemispira, 1510. + holospira, 1509. + merospira, 1510. + scalaris, 1509. + Spirocyrtoma, 1509. + Spironetta, 701. + Spironilla, 702. + Spironium, 701. + arbustum, 702. + diagonale, 702. + octonium, 701. + spinosum, 702. + Spongaster, 596. + cruciatus, 597. + orthogonus, 598. + pentacyclus, 598. + quadratus, 597. + scyllaeus, 598. + tetras, 597. + Spongasteriscus, 594. + armatus, 595. + clavatus, 595. + furcatus, 595. + mucronatus, 595. + myelastrum, 596. + ovatus, 594. + quadricornis, 596. + tetraceros, 596. + Spongatractus, 350. + fusiformis, 351. + pachystylus, 350. + streptacanthus, 351. + Spongechinus, 272. + cavus, 273. + _multiaculeatus_, 271. + serrulatus, 273. + setosus, 273. + SPONGELLIPSIDA, 341. + Spongellipsis, 341. + aplysina, 342. + aspera, 342. + laevis, 342. + setosa, 342. + spinosa, 342. + Spongiomma, 270. + asteroides, 272. + clavatum, 271. + denticulatum, 270. + helioides, 271. + multiaculeum, 271. + radiatum, 270. + spathillatum, 270. + SPONGIOMMIDA, 270. + SPONGOBRACHIDA, 587. + Spongobrachium, 587. + ellipticum, 588. + lanceolatum, 588. + Spongocore, 346. + chrysalis, 346. + cincta, 346. + diplocylindrica, 346. + puella, 347. + pupula, 347. + velata, 347. + _Spongocyclia_, 577. + _charybdoea_, 593. + _cycloides_, 578. + _elliptica_, 588. + _orthogona_, 598. + _scyllaea_, 598. + _triangularis_, 578. + SPONGOCYCLIDA, 573. + Spongocyrtis, 1188. + arachnoides, 1189. + montis ovis, 1189. + Spongodictyon, 90. + arcadophoron, 91. + cavernosum, 91. + spongiosum, 90. + trigonizon, 91. + SPONGODISCIDA, 573. + Spongodisculus, 576. + Spongodiscus, 576. + _aculeatus_, 583. + biconcavus, 577. + _charybdoeus_, 593. + cycloides, 578. + _ellipticus_, 588. + favus, 577. + florealis, 578. + mediterraneus, 576. + _orthogonus_, 598. + _quadricornis_, 596. + radiatus, 576. + resurgens, 577. + _scyllaeus_, 598. + spiralis, 578. + spongocyclia, 578. + Spongodruppa, 349. + elliptica, 350. + frangula, 349. + lentisca, 349. + pistacia, 349. + polyacantha, 350. + terebintha, 349. + SPONGODRUPPIDA, 348. + Spongodrymus, 272. + abietinus, 272. + elaphococcus, 272. + SPONGOLARCIDA, 613. + Spongolarcus, 613. + amphicentria, 614. + dimensivus, 613. + lentellipsis, 613. + triaxonius, 613. + Spongolena, 587. + cypselura, 588. + rhopalura, 587. + spongura, 587. + Spongoliva, 352. + amygdalina, 352. + cerasina, 352. + daturina, 353. + opuntina, 352. + persicina, 352. + prunulina, 352. + Spongolonche, 579. + amphistyla, 580. + conostyla, 580. + Spongolonchis, 149. + compacta, 149. + laxa, 149. + Spongomelissa, 1209. + spongiosa, 1210. + SPONGOPHACIDA, 575. + Spongophacus, 579. + periphaena, 579. + Spongophortis, 711. + larnacilla, 711. + radiosa, 711. + spongiosa, 711. + Spongopila, 274. + dichotoma, 274. + verticillata, 275. + Spongoplegma, 89. + antarcticum, 90. + Spongoprunum, 347. + amphicylindrus, 348. + amphilonche, 347. + atractuas, 348. + Spongopyramis, 1260. + spongiosa, 1261. + spongoplecta, 1261. + Spongosphaera, 282. + helioides, 283. + _pachystyla_, 350. + polyacantha, 282. + quadricuspis, 283. + _rhabdostyla_, 584. + streptacantha, 282. + SPONGOSPHAERIDA, 52. + Spongospira, 578. + _florealis_, 578. + _spiralis_, 578. + Spongostaurus, 582. + cruciatus, 582. + hastatus, 582. + quadratus, 582. + serratus, 582. + SPONGOSTYLIDA, 148. + Spongostylidium, 150. + streptacanthum, 150. + Spongostylus, 149. + gladiatus, 150. + hastatus, 149. + _prunococcus_, 354. + serratus, 150. + Spongothamnus, 274. + furcatus, 274. + scoparius, 274. + Spongotripus, 580. + irregularis, 581. + neumayri, 581. + regularis, 580. + strepsiceros, 581. + ypsilon, 581. + SPONGOTROCHIDA, 579. + Spongotrochiscus, 585. + Spongotrochus, 585. + _arachnius_, 583. + brevispinus, 586. + _craticulatus_, 583. + ehrenbergii, 1763. + _heteracanthus_, 584. + longispinus, 586. + multispinus, 586. + parma, 587. + scutella, 586. + SPONGURIDA, 339. + Spongurus, 343. + asper, 344. + cylindricus, 344. + phalanga, 343. + radians, 345. + _salpa_, 614. + spongechinus, 345. + stuparius, 343. + stypticus, 343. + tricolus, 344. + Spongoxiphus, 353. + prunococcus, 354. + sphaerococcus, 353. + SPUMELLARIA, 6. + Spyrida, 1015. + SPYRIDINA, 1015. + _Spyridobotrys_, 1083. + _trinacria_, 1083. + SPYROIDEA, 1015. + Stauracantha, 761. + bifurca, 764. + diplostaura, 762. + johannis, 763. + murrayana, 763. + orthostaura, 762. + pinnulata, 763. + quadrifurca, 764. + scalaris, 763. + stauraspis, 764. + tetrastaura, 762. + STAURACANTHIDA, 758. + Stauracanthidium, 764. + Stauracanthonium, 762. + STAURACONTIDA, 163. + Stauracontium, 163. + antarcticum, 165. + cruciferum, 164. + daturaeforme, 164. + papillosum, 165. + setosum, 165. + sparganium, 165. + tetracanthum, 164. + tetracontium, 164. + Stauractinium, 478. + Stauractura, 477. + medusina, 478. + quadrata, 478. + tetragona, 478. + Stauracturium, 477. + Stauralastrum, 540. + antiquum, 541. + clavigerum, 541. + cruciforme, 540. + dilatatum, 541. + horridum, 542. + lanceolatum, 540. + ordo, 540. + rhopalophorum, 541. + staurolonche, 542. + Staurancistra, 162. + quadricuspis, 162. + Staurasparium, 831. + STAURASPIDA, 830. + Stauraspidium, 831. + Stauraspis, 831. + cruciata, 831. + furcata, 832. + stauracantha, 832. + xiphacantha, 831. + Staurectodiscus, 416. + Staurentodiscus, 416. + STAUROCARYIDA, 167. + Staurocaryum, 167. + arborescens, 167. + STAUROCROMYIDA, 166. + Staurocromyum, 166. + quadrispinum, 166. + quadruplex, 166. + Staurocyclia, 465. + cruciata, 465. + magniducis, 466. + phacostaurus, 465. + serrata, 465. + Staurodictya, 506. + ciliata, 506. + cruciata, 507. + elegans, 507. + grandis, 508. + medusa, 506. + ocellata, 508. + quadrispina, 507. + splendens, 508. + Staurodoras, 168. + liassica, 168. + mojsisovicsi, 168. + spongosphaera, 168. + wandae, 169. + STAURODORIDA, 168. + Staurolithium, 771. + _cruciatum_, 771. + Staurolonche, 159. + aperta, 159. + brunonis, 159. + epicurii, 161. + feuerbachii, 160. + gassendii, 161. + hexagona, 158. + holbachii, 160. + lucretii, 161. + moleschottii, 160. + pertusa, 159. + spinozae, 159. + straussii, 160. + STAUROLONCHIDA, 158. + Staurolonchidium, 162. + artioscelides, 162. + perspicuum, 162. + Stauropelta, 859. + cruciata, 859. + stauropora, 859. + Staurosphaera, 153. + andreae, 154. + apostolorum, 155. + bartholomaei, 156. + christiana, 153. + crassa, 155. + cruciata, 153. + jacobi, 154. + johannis, 153. + judae, 155. + matthaei, 156. + pauli, 153. + petri, 153. + phillippi, 154. + simonis, 154. + thaddaei, 156. + thomae, 155. + STAUROSPHAERIDA, 151. + Staurospira, 507. + STAUROSTYLIDA, 152. + Staurostylus, 156. + germanicus, 157. + graecus, 156. + latinus, 157. + STAUROTHOLIDA, 670. + Staurotholonium, 675. + alternatum, 675. + bicruciatum, 675. + biquadratum, 675. + lenticulare, 676. + octodoratium, 676. + octodoronium, 676. + Staurotholus, 673. + cruciatus, 673. + decastylus, 674. + dodecastylus, 674. + octostylus, 674. + polystylus, 674. + quadratus, 673. + tetrastylus, 673. + Stauroxiphos, 163. + gladius, 163. + Stegaspis, 819. + Stephanastrum, 549. + capitatum, 549. + quadratum, 549. + rhombus, 549. + STEPHANIDA, 937. + Stephaniscus, 965. + medusinus, 965. + quadrifurcus, 965. + quadrigatus, 965. + tetrapodius, 965. + Stephanium, 952. + quadrupes, 952. + tetrapus, 952. + Stephanolithia, 953. + _muelleri_, 959. + _spinescens_, 958. + Stephanophaena, 1178. + Stephanospyris, 1042. + cordata, 1042. + excellens, 1043. + verticillata, 1043. + STEPHIDA, 931. + STEPHOIDEA, 931. + Stichocampe, 1443. + convergens, 1444. + divergens, 1444. + Stichocapsa, 1515. + compacta, 1517. + compressa, 1516. + cylindrica, 1518. + hexacola, 1517. + monstrosa, 1517. + paniscus, 1518. + pentacola, 1517. + pyriformis, 1516. + quadrigata, 1515. + radicula, 1518. + subglobosa, 1516. + subligata, 1518. + tetracola, 1515. + tricincta, 1516. + STICHOCAPSIDA, 1511. + STICHOCORIDA, 1468. + Stichocorys, 1479. + baerii, 1479. + huschkei, 1480. + muelleri, 1480. + okenii, 1480. + panderi, 1479. + rathkei, 1480. + wolffii, 1479. + STICHOCYRTIDA, 1434. + Stichocyrtis, 1489. + Sticholagena, 1449. + Stichopera, 1447. + clavata, 1449. + lagena, 1448. + ovata, 1448. + pectinata, 1449. + serrata, 1448. + verticillata, 1449. + STICHOPERIDA, 1447. + Stichoperina, 1448. + Stichophaena, 1465. + darwiniana, 1465. + goetheana, 1466. + nonaria, 1466. + novena, 1466. + ritteriana, 1465. + STICHOPHAENIDA, 1463. + Stichophaenidium, 1465. + Stichophaenoma, 1466. + STICHOPHORMIDA, 1454. + Stichophormis, 1454. + cornutella, 1455. + lucerna, 1455. + novena, 1455. + pyramidalis, 1454. + radiata, 1456. + Stichophormiscus, 1455. + Stichophormium, 1454. + STICHOPILIDA, 1436. + Stichopilidium, 1438. + Stichopilium, 1436. + bicorne, 1437. + campanulatum, 1438. + cortina, 1437. + costatum, 1437. + davisianum, 1437. + macropterum, 1438. + pectinatum, 1439. + thoracopterum, 1439. + triserratum, 1438. + Stichopodium, 1447. + dictyopodium, 1447. + Stichopterium, 1444. + dictyopodium, 1445. + pterocanium, 1445. + virgineum, 1445. + _Stichopterygium_, 1442. + _tanypterum_, 1442. + _anomalum_, 1442. + Stigmosphaera, 68. + actinocentra, 68. + Stomatodiscus, 502. + amphistomus, 502. + osculatus, 503. + Streblacantha, 706. + calcarina, 706. + hastigerina, 707. + siderolina, 706. + STREBLACANTHIDA, 704. + Streblonia, 704. + bulimina, 705. + globigerina, 704. + planorbulina, 705. + polymorphina, 705. + pulvinulina, 706. + rosalina, 705. + _siderolina_, 706. + uvigerina, 704. + STREBLONIDA, 702. + Streblopyle, 707. + helicina, 707. + spirulina, 707. + STREBLOPYLIDA, 704. + Stylactis, 532. + _triangulum_, 533. + _zittelii_, 534. + Stylartus, 357. + bipolaris, 357. + bicuspis, 357. + palatus, 358. + penicillus, 358. + Stylatractus, 328. + carduus, 330. + compactus, 329. + disetanius, 331. + fusiformis, 329. + giganteus, 329. + neptunus, 328. + papillosus, 331. + sethoporus, 330. + variabilis, 330. + Stylectodiscus, 413. + Stylentodiscus, 413. + Stylochlamydium, 514. + aequale, 515. + asteriscus, 514. + limbatum, 514. + perispirale, 515. + spongiosum, 516. + venustum, 515. + Stylocoronis, 982. + Stylocromyum, 147. + amphiconus, 147. + amphipyramis, 147. + _tetraphractum_, 335. + Stylocyclia, 462. + amphacantha, 463. + _arachnia_, 510. + dimidiata, 462. + excavata, 463. + prionacantha, 462. + STYLOCYCLIDA, 461. + Stylodictya, 509. + arachnia, 510. + _bispiralis_, 497. + centrospira, 512. + clavata, 513. + dujardinii, 513. + echinastrum, 513. + _forbesii_, 510. + gracilis, 509. + haeckelii, 510. + hastata, 510. + heliospira, 512. + hertwigii, 513. + multispina, 510. + _ocellata_, 508. + octogonia, 511. + perispira, 511. + _quadrispina_, 507. + setigera, 512. + solmaris, 511. + _splendens_, 508. + stellata, 510. + STYLODICTYIDA, 503. + Stylodiscus, 413. + amphistylus, 413. + endostylus, 413. + Stylosphaera, 133. + calliope, 134. + _carduus_, 330. + clio, 134. + _coronata_, 326. + dixyphos, 135. + erato, 137. + euterpe, 135. + _flexuosa_, 138. + _hippocampus_, 324. + hispida, 136. + _holosphaera_, 150. + jugata, 137. + _laevis_, 327. + liostylus, 136. + _megadictya_, 301. + melpomene, 135. + musa, 133. + nana, 136. + _ophidium_, 140. + polyhymnia, 134. + _radiosa_, 334. + setosa, 135. + _spinulosa_, 332. + _sulcata_, 333. + terpsichore, 137. + _testudo_, 325. + thalia, 137. + urania, 134. + STYLOSPHAERIDA, 121. + Stylospira, 512. + _arachnia_, 513. + _dujardinii_, 513. + _heliospira_, 512. + Stylospongia, 584. + _huxleyi_, 585. + Stylospongidium, 586. + _geddesii_, 585. + Stylostaurus, 157. + caudatus, 157. + gladiatus, 158. + Stylotrochiscus, 583. + Stylotrochus, 583. + arachnius, 583. + craticulatus, 583. + geddesii, 585. + helianthus, 584. + heteracanthus, 584. + huxleyi, 585. + rhabdostylus, 584. + Stypolarcus, 614. + spongiosus, 614. + Styposphaera, 86. + spongiacea, 87. + spumacea, 87. + stupacea, 87. + + Taurospyris, 1058. + bovina, 1058. + cervina, 1058. + Tessarasparium, 835. + TESSARASPIDA, 830. + Tessaraspidium, 838. + _quadratum_, 838. + Tessaraspis, 835. + arachnoides, 836. + circularis, 837. + concreta, 838. + diodon, 837. + _elegans_, 844. + _icosastaura_, 846. + hexagonalis, 836. + irregularis, 838. + micropora, 827. + pentagonalis, 836. + quadrata, 838. + quadriforis, 837. + rotunda, 838. + tetragonalis, 836. + trigonalis, 836. + Tessarastrum, 547. + brunonis, 548. + democriti, 548. + spinozae, 546. + straussii, 547. + Tessarospyris, 1045. + clathrobursa, 1045. + nuciformis, 1046. + seminulum, 1046. + _Tetracorethra_, 1044. + _mirabilis_, 1044. + Tetracoronis, 981. + Tetracranastrum, 552. + Tetracubus, 994. + TETRACYRTIDA, 1434. + Tetrahedrina, 1238. + pyramidalis, 1238. + pyriformis, 1238. + quadricornis, 1239. + Tetralacorys, 1370. + Tetraphormis, 1243. + Tetraplagia, 911. + abietina, 912. + geometrica, 911. + phaenaxonia, 911. + TETRAPLAGIDA, 941. + Tetraplecta, 923. + pinigera, 924. + quadricornis, 924. + tetrahedra, 923. + TETRAPLECTIDA, 923. + Tetrapyle, 645. + cardiopyle, 646. + circopyle, 645. + circularis, 645. + cladacantha, 648. + cruciata, 647. + dodecaceros, 649. + fusiformis, 646. + nephropyle, 645. + octacantha, 648. + pleuracantha, 646. + pluteus, 649. + _polyacantha_, 1761. + quadricornis, 647. + quadrigata, 648. + quadriloba, 645. + staurophora, 647. + tetracantha, 647. + transversa, 646. + turrita, 649. + Tetrapylonium, 657. + armatum, 659. + octacanthum, 658. + pantellipticum, 658. + quadrangulare, 658. + reniforme, 658. + Tetrarrhabda, 1044. + Tetrasolenia, 113. + _quadrata_, 113. + _venosa_, 114. + TETRASPHAERIDA, 52. + TETRASPYRIDA, 1043. + Tetraspyris, 1043. + calcarata, 1045. + cubica, 1044. + scoparia, 1045. + stephanium, 1044. + tetracorethra, 1044. + Tetroniscus, 487. + _Thamnospyris_, 1070. + _thamnopodia_, 1071. + Thalassicolla, 18. + _acufera_, 46. + australis, 20. + _cavispicula_, 1551. + maculata, 21. + melacapsa, 21. + nucleata, 20. + _papillosa_, 22. + _pelagica_, 23. + pellucida, 19. + _punctata_, 25. + _sanguinolenta_, 22. + spumida, 19. + zanclea, 19. + Thalassicollarium, 18. + THALASSICOLLIDA, 10. + Thalassicollidium, 20. + Thalassolampe, 16. + margarodes, 16. + maxima, 17. + _primordialis_, 13. + Thalassophysa, 21. + papillosa, 22. + pelagica, 23. + sanguinolenta, 22. + Thalassopila, 17. + cladococcus, 17. + Thalassoplancta, 36. + brevispicula, 36. + _cavispicula_, 1551. + longispicula, 36. + Thalassosphaera, 31. + belonium, 31. + _bifurca_, 33. + rhaphidium, 31. + THALASSOSPHAERIDA, 29. + Thalassoxanthium, 32. + bifurcum, 33. + cervicorne, 33. + furcatum, 33. + hexactinium, 32. + medusinum, 32. + octoceras, 34. + ovodimare, 34. + punctatum, 34. + triactinium, 32. + triradiatum, 32. + Thecosphaera, 78. + aequorea, 80. + capillacea, 81. + diplococcus, 81. + dodecactis, 82. + entactinia, 81. + favosa, 79. + floribunda, 79. + icosactis, 82. + inermis, 80. + maxima, 82. + medusa, 80. + micropora, 81. + phaenaxonia, 79. + triplodictyon, 79. + THECOSPHAERIDA, 78. + Theocalyptra, 1397. + cornuta, 1398. + discoides, 1398. + orci, 1397. + veneris, 1397. + Theocampana, 1422. + Theocampe, 1422. + cassis, 1424. + collaris, 1425. + costata, 1426. + cryptocephala, 1426. + cryptoprora, 1423. + ehrenbergii, 1422. + gemmata, 1425. + megalopora, 1425. + nucula, 1423. + ovulum, 1424. + pirum, 1423. + sphaerothorax, 1424. + stenostoma, 1423. + versipellis, 1425. + Theocentra, 1424. + Theocapsa, 1426. + aldrovandi, 1428. + aristotelis, 1427. + baerii, 1430. + cuvieri, 1430. + darwinii, 1431. + democriti, 1427. + forskalii, 1429. + galeni, 1427. + gessneri, 1428. + lamarckii, 1430. + linnaei, 1429. + malpighii, 1428. + muelleri, 1431. + pallasii, 1429. + plinii, 1427. + rathkei, 1430. + sarsii, 1431. + schwannii, 1431. + wolffii, 1429. + wottonis, 1428. + Theocapsetta, 1426. + THEOCAPSIDA, 1426. + Theocapsilla, 1427. + Theocapsomma, 1428. + Theocapsura, 1430. + Theoconus, 1399. + aegeus, 1400. + amplus, 1402. + ampullaceus, 1402. + ariadnes, 1402. + campanulatus, 1400. + dionysius, 1402. + ficus, 1403. + jovis, 1401. + junonis, 1401. + laterna, 1403. + longicornis, 1401. + orthoconus, 1400. + zancleus, 1399. + zanguebaricus, 1400. + Theocorax, 1399. + Theocorbis, 1401. + THEOCORIDA, 1396. + Theocoronium, 1415. + Theocorusca, 1407. + Theocorys, 1414. + alauda, 1418. + ampullacea, 1402. + apollinis, 1418. + attenuata, 1417. + bachabunda, 1417. + cretica, 1415. + dianae, 1416. + _ficus_, 1403. + hyalothorax, 1417. + _longicornis_, 1370. + martis, 1419. + mercurii, 1419. + minervae, 1419. + obliqua, 1417. + ovata, 1416. + plutonis, 1416. + scolopax, 1416. + sphaerophila, 1418. + tuberculata, 1419. + turgidula, 1415. + veneris, 1415. + Theocorypha, 1405. + Theocorythium, 1416. + THEOCYRTIDA, 1395. + Theocyrtis, 1405. + aspera, 1408. + barbadensis, 1406. + cylindrica, 1406. + elegans, 1406. + macroceros, 1407. + microtheca, 1407. + oenophila, 1408. + paupera, 1407. + proserpinae, 1408. + ptychodes, 1408. + trachelius, 1405. + Theodiscoma, 414. + Theodiscura, 415. + Theodiscus, 413. + christianus, 414. + divinus, 414. + nirwana, 415. + trinitatis, 414. + vanitatis, 415. + Theopera, 1357. + chytropus, 1358. + cortina, 1358. + fusiformis, 1357. + luscinia, 1358. + prismatica, 1357. + pyramis, 1357. + THEOPERIDA, 1354. + Theophaena, 1394. + corona, 1394. + nonaria, 1395. + THEOPHAENIDA, 1393. + THEOPHORMIDA, 1366. + Theophormis, 1366. + callipilium, 1367. + cruciata, 1367. + medusa, 1367. + senaria, 1368. + THEOPILIDA, 1315. + Theosyringium, 1409. + pipetta, 1409. + siphonium, 1409. + tibia, 1409. + tubulus, 1411. + Theopilium, 1321. + cranoides, 1322. + tricostatum, 1322. + triradiatum, 1322. + Theopodium, 1328. + pyramidale, 1328. + tricostatum, 1328. + THEROSPYRIDA, 1055. + Therospyris, 1058. + canis, 1058. + felis, 1059. + leo, 1059. + Tholartus, 663. + isocolus, 664. + paniscus, 664. + sagitta, 665. + tricolus, 664. + tripanis, 665. + Tholocubus, 677. + tessellatus, 677. + tesseralis, 678. + tesserarius, 677. + Tholodes, 665. + cupula, 665. + Tholoma, 671. + metallasson, 672. + quadrigeminum, 672. + THOLONIDA, 660. + Tholonium, 678. + bicubicum, 678. + ellipticum, 679. + hexonium, 679. + sphaericum, 679. + sphaeronium, 679. + Tholospira, 699. + cervicornis, 700. + dendrophora, 700. + hystrix, 700. + nautiloides, 699. + spinosa, 696. + Tholospirema, 699. + Tholospironium, 700. + THOLOSPYRIDA, 1077. + Tholospyridium, 1079. + Tholospyris, 1078. + cupola, 1080. + fenestrata, 1079. + galeata, 1079. + ramosa, 1079. + tripodiscus, 1079. + Tholospyrium, 1078. + Tholostaurus, 670. + cruciformis, 670. + dodecabeles, 671. + octobelonis, 671. + polybelonis, 671. + quadrigatus, 670. + tetrabelonis, 671. + _Tholothauma_, 682. + _ellipsoides_, 682. + Thoracaspis, 862. + bipennis, 862. + circopora, 862. + ellipsoides, 862. + nephropora, 862. + Thyrsocyrtis, 1350. + _anthophora_, 1491. + arborescens, 1350. + _bachabunda_, 1417. + _bromia_, 1349. + _dionysia_, 1402. + furcata, 1351. + _jacchia_, 1402. + _lyaea_, 1348. + _oenophila_, 1408. + _radicata_, 1351. + _reticulata_, 1274. + rhizodon, 1350. + rhizopodium, 1351. + rhizopus, 1351. + trifida, 1352. + TIAROSPYRIDA, 1078. + Tiarospyris, 1082. + amphora, 1083. + galea, 1082. + mitra, 1082. + pervia, 1082. + Toxarium, 995. + bifurcum, 997. + circospyris, 995. + constrictum, 996. + cordatum, 996. + costatum, 997. + furcatum, 997. + pedatum, 997. + subcirculare, 996. + thorax, 996. + Toxellium, 995. + Toxidium, 996. + Toxonium, 997. + TREMATODISCIDA, 491. + Trematodiscus, 492. + _concentricus_, 492. + _ellipticus_, 494. + _flustrella_, 493. + _haeckelii_, 1763. + _helicoides_, 496. + _heterocyclus_, 494. + _macroporus_, 493. + _microporus_, 493. + _orbiculatus_, 492. + _sorites_, 493. + _soritoides_, 1762. + Triacartus, 1436. + _Triactinosphaera_, 590. + _zittelii_, 590. + Triactiscus, 432. + tricuspis, 432. + tripodiscus, 432. + tripyramis, 432. + Tribonosphaera, 98. + centripetalis, 98. + Triceraspyris, 1029. + arborescens, 1032. + corallorrhiza, 1031. + cortiniscus, 1030. + damaecornis, 1032. + didiceros, 1030. + furcata, 1031. + gazella, 1031. + giraffa, 1031. + longicornis, 1032. + maniculata, 1031. + tripodiscus, 1030. + _Trichogromia_, 1661. + _hirsuta_, 1661. + Tricircarium, 985. + Tricirconium, 986. + Tricolocampe, 1411. + amphizona, 1413. + arcta, 1414. + cingulata, 1414. + cylindrica, 1412. + doliolum, 1414. + panthera, 1413. + polyzona, 1412. + pupa, 1412. + stenozona, 1413. + urnula, 1413. + Tricolocampium, 1412. + Tricolocamptra, 1413. + Tricolocapsa, 1431. + brownii, 1433. + decandollei, 1433. + dioscoridis, 1432. + linnaei, 1432. + schleidenii, 1433. + theophrasti, 1432. + Tricolocapsium, 1433. + Tricolocapsula, 1432. + Tricolospyris, 1097. + baconiana, 1098. + kantiana, 1098. + leibnitziana, 1098. + newtoniana, 1098. + _Tricranastrum_, 541. + _wyvillei_, 551. + Trictenartus, 1440. + Tricyclarium, 987. + Tricyclidium, 984. + dictyospyris, 984. + semantrum, 985. + Tricyclonium, 987. + TRICYRTIDA, 1313. + Tridictyopus, 1145. + conulus, 1145. + elegans, 1145. + vatillum, 1145. + Trigonactinium, 472. + Trigonactura, 471. + lanceolata, 472. + pythagorae, 471. + rhopalastrella, 471. + triacantha, 472. + trigonobrachia, 472. + trigonodiscus, 472. + trixiphos, 473. + Trigonacturium, 471. + Trigonastrum, 539. + gegenbauri, 539. + krohnii, 539. + regulare, 539. + Trigonocyclia, 464. + triangularis, 464. + Triodiscus, 566. + lenticula, 566. + trigonus, 567. + spinosus, 567. + Triolena, 564. + hexabelone, 564. + primordialis, 564. + tribelone, 564. + trigonalis, 564. + trispinosa, 564. + Trioniscus, 486. + Triopyle, 564. + circulus, 565. + cordigera, 565. + hexagona, 565. + renigera, 565. + spinigera, 566. + trigona, 565. + TRIOPYLIDA, 563. + TRIOSPHAERIDA, 52. + Triospyridium, 1032. + Triospyris, 1030. + Triospyrium, 1030. + TRIOSTEPHIDA, 967. + Triostephus, 983. + Tripilidium, 1140. + cladopodium, 1142. + clavatum, 1141. + cortina, 1140, + costatum, 1141. + dichopodium, 1142. + elongatum, 1142. + hemisphaericum, 1140. + lychnocanium, 1141. + ovatum, 1141. + Triplagia, 908. + horizontalis, 909. + primordialis, 909. + triradialis, 909. + TRIPLAGIDA, 908. + Triplecta, 921. + triactis, 922. + triangulum, 921. + TRIPLECTIDA, 921. + TRIPLOZONARIA, 656. + TRIPOCALPIDA, 1133. + Tripocalpis, 1135. + cortinaris, 1137. + galea, 1136. + plectaniscus, 1136. + tricostata, 1136. + triserrata, 1136. + Tripocoronis, 981. + Tripocubus, 994. + TRIPOCYRTIDA, 1192. + Tripocyrtis, 1201. + _challengeri_, 1231. + plagoniscus, 1201. + plectaniscus, 1202. + tripodiscus, 1202. + Tripodictya, 505. + triacantha, 505. + tribelonia, 505. + trigonaria, 505. + Tripodiscinus, 1143. + Tripodisculus, 1144. + Tripodocorys, 1142. + Tripodonium, 1137. + campanulatum, 1137. + ovatum, 1137. + Tripodiscium, 1143. + campanula, 1144. + clavatum, 1143. + furcatum, 1144. + ovatum, 1143. + ramosum, 1144. + sphaerocephalum, 1144. + tristylospyris, 1143. + Tripospyrantha, 1025. + Tripospyrella, 1026. + TRIPOSPYRIDA, 1025. + Tripospyris, 1025. + capitata, 1025. + clavata, 1028. + conifera, 1027. + cortina, 1025. + cortiniscus, 1026. + diomma, 1026. + eucolpos, 1029. + _euscenium_, 1147. + furcata, 1021. + hexomma, 1028. + semantidium, 1029. + semantis, 1026. + semantrum, 1027. + tessaromma, 1028. + tribrachiata, 1029. + triomma, 1026. + triplecta, 1027. + Tripospyrissa, 1027. + Tripospyromma, 1028. + Tripterocalpis, 1137. + conoptera, 1138. + ogmoptera, 1138. + phylloptera, 1138. + TRIPYLEA, 1521. + _Trisolenia_, 113. + _megalactis_, 114. + _zanguebarica_, 97. + Trissocircus, 985. + binellipsis, 985. + globus, 986. + lentellipsis, 985. + octahedrus, 986. + octostoma, 986. + TRISSOCYCLIDA, 982. + Trissocyclus, 986. + sphaeridium, 987. + stauroporus, 987. + triaxonius, 987. + Trissopilium, 1138. + lithomelissa, 1139. + tetraplecta, 1139. + Tristephaniscus, 984, + Tristephanium, 982. + dimensivum, 983. + hertwigii, 983. + octopyle, 983. + quadricorne, 984. + Tristylocorys, 1140. + Tristylospyris, 1032. + clavipes, 1033. + furcata, 1034. + palmipes, 1033. + ramosa, 1034. + scaphipes, 1033. + triceros, 1033. + tripodiscium, 1034. + Tristylospyrula, 1033. + Tristylospyrium, 1034. + Trizonium, 637. + amphibelonium, 638. + constrictum, 637. + decabelonium, 639. + dodecabelos, 640. + hexabelonium, 639. + hexagonium, 638. + octobelonium, 639. + octogonium, 638. + pleurobelonium, 638. + staurobelonium, 639. + tricinctum, 637. + TROCHODISCIDA, 412. + Trochodisculus, 417. + Trochodiscus, 417. + cenophacus, 417. + cingillum, 419. + echiniscus, 418. + medusinus, 417. + odontotrochus, 418. + solaris, 418. + stellaris, 418. + Trypanosphaera, 109. + coronata, 110. + dentata, 110. + terebrata, 110. + transformata, 111. + trepanata, 110. + TYMPANIDA, 987. + Tympanidium, 1003. + barbadense, 1004. + binoctonum, 1004. + foliosum, 1003. + spinosum, 1003. + staurocircum, 1004. + Tympaniscus, 1001. + bipes, 1001. + corona, 1001. + dipodiscus, 1001. + _dizonius_, 973. + dodecaster, 1002. + fibula, 1002. + quadrupes, 1002. + tripodiscus, 1002. + Tympanura, 1003. + Tympanomma, 1004. + Tuscarantha, 1706. + Tuscaretta, 1707. + Tuscaridium, 1709. + cygneum, 1709. + lithornithium, 1710. + Tuscarilla, 1708. + Tuscarora, 1706. + belknapii, 1708. + bisternaria, 1706. + _cygnea_, 1709. + murrayi, 1706. + porcellana, 1708. + tetrahedra, 1707. + tubulosa, 1707. + wyvillei, 1707. + TUSCARORIDA, 1702. + Tuscarusa, 1707. + medusa, 1709. + + Urocyrtis, 1762. + amaliae, 1762. + emmae, 1762. + stephanii, 1762. + + Xanthiosphaera, 119. + capillacea, 119. + erinacea, 120. + lappacea, 120. + Xiphacantha, 758. + alata, 761. + ancorata, 760. + ciliata, 761 + _cruciata_, 754. + crucifera, 759. + emarginata, 759. + falcata, 759. + _foliosa_, 754. + macroptera, 760. + _murrayana_, 763. + _pectinata_, 757. + platyptera, 761. + quadridentata, 758. + _serrata_, 757. + spinulosa, 759. + stauroptera, 760. + trigonoptera, 760. + Xiphacanthidium, 760. + Xiphacanthonium, 758. + Xiphatractus, 332. + armadillo, 332. + chlamydophorus, 333. + dasypus, 333. + euphractus, 332. + glyptodon, 334. + radiosus, 334. + spinulosus, 332. + sulcatus, 333. + Xiphodictya, 503. + amphibelonia, 503. + amphirrhopalia, 504. + staurospira, 504. + heliospira, 504. + Xiphoptera, 777. + dodecactena, 778. + icosactena, 778. + tessaractena, 778. + Xiphosphaera, 123. + astraea, 126. + _bipolaris_, 297. + ceres, 126. + clavigera, 126. + euphrosyne, 124. + flora, 125. + gaea, 123. + gigantea, 125. + hebe, 127. + luna, 123. + juno, 125. + maxima, 124. + pallas, 124. + planeta, 123. + venus, 123. + vesta, 126. + Xiphospira, 504. + XIPHOSTYLIDA, 122. + Xiphostylus, 127. + alauda, 128. + alca, 130. + alcedo, 127. + anhinga, 128. + ardea, 131. + cuculus, 129. + edolius, 130. + emberiza, 131. + falco, 130. + gallus, 128. + motacilla, 127. + phasianus, 127. + picus, 129. + trochilus, 129. + trogon, 129. + + ZONARIDA, 682. + Zonarium, 684. + octangulum, 685. + quadrigatum, 685. + quadrispinum, 685. + tetratholium, 685. + Zonaspis, 833. + aequatorialis, 834. + cingulata, 834. + fragilis, 833. + Zonidium, 687. + octostylium, 688. + octotholium, 688. + Zoniscus, 686. + hexathalamius, 686. + hexatholius, 687. + octacanthus, 667. + rectangulus, 686. + tetracanthus, 687. + ZONODISCIDA, 411. + Zonodiscus, 412. + saturnalis, 412. + Zygacantha, 746. + complanata, 748. + compressa, 747. + costata, 746. + dichotoma, 747. + dicopa, 748. + foliacea, 748. + furcata, 747. + lanceolata, 746. + semicompressa, 748. + Zygacantharium, 746. + ZYGACANTHIDA, 742. + Zygacanthidium, 747. + Zygacanthonium, 748. + ZYGARTIDA, 397. + Zygartus, 401. + chrysalis, 401. + doliolum, 401. + _larvalis_, 398. + _virginis_, 369. + Zygocampe, 399. + chrysalidium, 400. + corasium, 400. + pupula, 399. + ZYGOCAMPIDA, 392. + Zygocircus, 945. + acacia, 947. + buetschlii, 948. + dodecanthus, 947. + hexagonus, 947. + pentagonus, 946. + polygonus, 947. + productus, 958. + rhombicus, 946. + sagittalis, 946. + tetragonus, 946. + trigonus, 946. + triquetrus, 347. + ZYGOCYRTIDA, 1015. + ZYGOSPYRIDA, 1021. + Zygospyris, 1055. + equus, 1056. + quadrupes, 1055. + Zygostaurus, 774. + amphithectus, 774. + arcuatus, 774. + caudatus, 775. + cornutus, 775. + frontalis, 775. + longicornis, 774. + sagittalis, 775. + ZYGOSTEPHANIDA, 970. + Zygostephaniscus, 972. + Zygostephanium, 972. + constrictum, 973. + dizonium, 973. + paradictyum, 973. + Zygostephanus, 970. + bicornis, 972. + dissocircus, 971. + muelleri, 971. + ramosus, 971. + reniformis, 972 + serratus, 971. + violina, 972. + + + +Notes. + + [1] _Cystidium_ = Small vesicle; [Greek: kystidion]. + + [2] _Nassella_ = Small wicker cage for fishing. + + [3] _Triplagia_ = Triangular or three-radial; [Greek: triplagios]. + + [4] _Plagiacantha_ = Having spines on the sides; [Greek: plagios], + [Greek: akantha]. + + [5] _Tetraplagia_ = Four-sided; [Greek: tetraplagios]. + + [6] _Plagoniscus_ = Side-windlass; [Greek: plagos], [Greek: oniskos]. + + [7] _Plagonidium_ = Small side-article; [Greek: plagonidion]. + + [8] _Plagiocarpa_ = Having its fruit (the central capsule) on the side; + [Greek: plagiokarpos]. + + [9] _Hexaplagia_ = Six-sided; [Greek: hexaplagios]. + + [10] _Plagonium_ = Side-article; [Greek: plagos], [Greek: onion]. + + [11] _Polyplagia_ = Manifold; [Greek: polyplagios]. + + [12] _Triplecta_ = Hunting net with three beams; [Greek: tris], [Greek: + plekte]. + + [13] _Plectophora_ = Bearing a hunting net; [Greek: plekte], [Greek: + phoros]. + + [14] _Tetraplecta_ = Hunting net with four beams; [Greek: tetra], [Greek: + plekte]. + + [15] _Plectaniscus_ = Shell of wickerwork; [Greek: plektaniskos]. + + [16] _Periplecta_ = Surrounded by a hunting net; [Greek: peri], [Greek: + plekte]. + + [17] _Hexaplecta_ = Hunting net with six beams; [Greek: hexa], [Greek: + plekte]. + + [18] _Plectanium_ = Small wickerwork or network; [Greek: plektane]. + + [19] _Polyplecta_ = Much entwined; [Greek: polyplektos]. + + [20] _Archicircus_ = Primordial ring; [Greek: archi], [Greek: kirkos]. + + [21] _Lithocircus_ = Ring of silex; [Greek: lithos], [Greek: kirkos]. + + [22] _Zygocircus_ = Yoked or symmetrical ring; [Greek: zygon], [Greek: + kirkos]. + + [23] _Dendrocircus_ = Ring bearing trees; [Greek: dendron], [Greek: + kirkos]. + + [24] _Cortina_ = Tripod. + + [25] _Stephanium_ = Small crown or garland; [Greek: stephanion]. + + [26] _Semantis_ = Signet-ring; [Greek: semantis]. + + [27] _Semantrum_ = Signet-ring; [Greek: semantron]. + + [28] _Semantidium_ = Small signet-ring; [Greek: semantidion]. + + [29] _Clathrocircus_ = Lattice-ring; [Greek: klethron], [Greek: kirkos]. + + [30] _Cortiniscus_ = Small cortina or tripod. + + [31] _Stephaniscus_ = Small coronet or garland; [Greek: stephaniskos]. + + [32] _Semantiscus_ = Small signet-ring; [Greek: semantiskos]. + + [33] _Zygostephanus_ = Yoked ring; [Greek: zygon], [Greek: stephanos]. + + [34] _Zygostephanium_ = Small yoked ring; [Greek: zygon], [Greek: + stephanion]. + + [35] _Coronidium_ = Small crown; [Greek: koronidion]. + + [36] _Acanthodesmia_ = Thorn-band; [Greek: akantha], [Greek: desmion]. + + [37] _Eucoronis_ = Good crown; [Greek: eu], [Greek: koronis]. + + [38] _Plectocoronis_ = Crown with framework; [Greek: plektos], [Greek: + koronis]. + + [39] _Podocoronis_ = Crown with feet; [Greek: pous], [Greek: koronis]. + + [40] _Tristephanium_ = Small crown with three rings; [Greek: tris], + [Greek: stephanion]. + + [41] _Tricyclidium_ = Composed of three small crossed circles; [Greek: + tris], [Greek: kyklidion]. + + [42] _Trissocircus_ = Composed of three crossed circles; [Greek: trissos], + [Greek: kirkos]. + + [43] _Trissocyclus_ = Composed of three crossed rings; [Greek: trissos], + [Greek: kyklos]. + + [44] _Protympanium_ = Primordial drum; [Greek: protympanion]. + + [45] _Acrocubus_ = Perfect cube; [Greek: akros], [Greek: kybos]. + + [46] _Toxarium_ = Small bow; [Greek: toxarion]. + + [47] _Microcubus_ = Small cube; [Greek: mikros], [Greek: kybos]. + + [48] _Octotympanum_ = Drum with eight gates; [Greek: okto], [Greek: + tympanon]. + + [49] _Tympaniscus_ = Little drum; [Greek: tympaniskos]. + + [50] _Tympanidium_ = Small drum; [Greek: tympanidion]. + + [51] _Paratympanum_ = Side-drum; [Greek: para], [Greek: tympanon]. + + [52] _Lithotympanum_ = Drum of silex; [Greek: lithos], [Greek: tympanon]. + + [53] _Dystympanium_ = Hideous drum; [Greek: dys], [Greek: tympanion]. + + [54] _Prismatium_ = A small prism; [Greek: prismation]. + + [55] _Pseudocubus_ = False cube; [Greek: pseudos], [Greek: kybos]. + + [56] _Lithocubus_ = Cube of silex; [Greek: lithos], [Greek: kybos]. + + [57] _Circotympanum_ = Drum with rings; [Greek: kirkos], [Greek: + tympanon]. + + [58] _Eutympanium_ = Nice small drum; [Greek: eu], [Greek: tympanion]. + + [59] _Tripospyris_ = Basket with a tripod; [Greek: tripos], [Greek: + spyris]. + + [60] _Triceraspyris_ = Basket with three horns; [Greek: trikeras], [Greek: + spyris] + + [61] _Tristylospyris_ = Basket with three styles; [Greek: tristylos], + [Greek: spyris]. + + [62] _Cephalospyris_ = Head-like basket; [Greek: kephale], [Greek: + spyris]. + + [63] _Dipospyris_ = Basket with two feet; [Greek: dipous], [Greek: + spyris]. + + [64] _Brachiospyris_ = Basket with two arms; [Greek: brachion], [Greek: + spyris]. + + [65] _Dendrospyris_ = Basket with arborescent feet; [Greek: dendron], + [Greek: spyris]. + + [66] _Dorcadospyris_ = Basket with two horns, similar to an antelope; + [Greek: dorkas], [Greek: spyris]. + + [67] _Gamospyris_ = Basket with two feet grown together; [Greek: gamos], + [Greek: spyris]. + + [68] _Stephanospyris_ = Basket with a garland; [Greek: stephanos], [Greek: + spyris]. + + [69] _Tetraspyris_ = Basket with four feet; [Greek: tetra], [Greek: + spyris]. + + [70] _Tessarospyris_ = Basket with four feet; [Greek: tessara], [Greek: + spyris]. + + [71] _Hexaspyris_ = Basket with six feet; [Greek: hexa], [Greek: spyris]. + + [72] _Liriospyris_ = Lily-basket; [Greek: leirion], [Greek: spyris]. + + [73] _Cantharospyris_ = Basket with six feet, like a beetle; [Greek: + kantharos], [Greek: spyris]. + + [74] _Clathrospyris_ = Latticed basket; [Greek: klethron], [Greek: + spyris]. + + [75] _Aegospyris_ = Goat-basket; [Greek: aigospyris]. + + [76] _Pentaspyris_ = Basket with five feet; [Greek: penta], [Greek: + spyris]. + + [77] _Zygospyris_ = Bilocular basket, with paired halves; [Greek: zyga], + [Greek: spyris]. + + [78] _Elaphospyris_ = Deer-basket; [Greek: elaphos], [Greek: spyris]. + + [79] _Taurospyris_ = Bull-basket; [Greek: tauros], [Greek: spyris]. + + [80] _Therospyris_ = Basket with four feet, like a beast; [Greek: ther], + [Greek: spyris]. + + [81] _Petalospyris_ = Leaf-basket; [Greek: petalos], [Greek: spyris]. + + [82] _Anthospyris_ = Flower-basket; [Greek: anthos], [Greek: spyris]. + + [83] _Ceratospyris_ = Horned basket; [Greek: keras], [Greek: spyris]. + + [84] _Gorgospyris_ = Medusiform basket; [Greek: gorgo], [Greek: spyris]. + + [85] _Circospyris_ = Basket with a ring; [Greek: kirkos], [Greek: spyris]. + + [86] _Dictyospyris_ = Net-basket; [Greek: diktyon], [Greek: spyris]. + + [87] _Tholospyris_ = Basket with a cupola; [Greek: tholos], [Greek: + spyris]. + + [88] _Lophospyris_ = Basket with a crest; [Greek: lophos], [Greek: + spyris]. + + [89] _Sepalospyris_ = Basket with leaves; [Greek: sepalon], [Greek: + spyris]. + + [90] _Tiarospyris_ = Basket with a cap; [Greek: tiara], [Greek: spyris]. + + [91] _Pylospyris_ = Basket with gates; [Greek: pyle], [Greek: spyris]. + + [92] _Acrospyris_ = Basket with an apical spine; [Greek: akra], [Greek: + spyris]. + + [93] _Phormospyris_ = Wicker-basket; [Greek: phormos], [Greek: spyris]. + + [94] _Patagospyris_ = Basket with a patagium; [Greek: patageion], [Greek: + spyris]. + + [95] _Rhodospyris_ = Rose-basket; [Greek: rhodon], [Greek: spyris]. + + [96] _Desmospyris_ = Basket with a band or string; [Greek: desmos], + [Greek: spyris]. + + [97] _Androspyris_ = Man-like wicker basket; [Greek: aner], [Greek: + spyris]. + + [98] _Lamprospyris_ = Splendid wicker-basket; [Greek: lampros], [Greek: + spyris]. + + [99] _Amphispyris_ = Basket with a cap on both sides; [Greek: amphi], + [Greek: spyris]. + +[100] _Tricolospyris_ = Wicker-basket with three joints; [Greek: trikolos], + [Greek: spyris]. + +[101] _Perispyris_ = Wicker-basket surrounded by an envelope; [Greek: + peri], [Greek: spyris]. + +[102] _Sphaerospyris_ = Spherical wicker-basket; [Greek: sphaira], [Greek: + spyris]. + +[103] _Nephrospyris_ = Kidney-shaped basket; [Greek: nephros], [Greek: + spyris]. + +[104] _Botryopera_ = Basket with grapes; [Greek: botrys], [Greek: pera]. + +[105] _Cannobotrys_ = Grape with tubes; [Greek: kanna], [Greek: botrys]. + +[106] _Acrobotrys_ = Perfect grape; [Greek: akros], [Greek: botrys]. + +[107] _Botryocella_ = Grape-pinnace; [Greek: botrys], [Greek: kella]. + +[108] _Lithobotrys_ = Stone grape; [Greek: lithos], [Greek: botrys]. + +[109] _Botryocyrtis_ = Basket with grapes; [Greek: botrys], [Greek: + kyrtis]. + +[110] _Pylobotrys_ = Grape with an aperture; [Greek: pyle], [Greek: + botrys]. + +[111] _Botryocampe_ = Caterpillar with a grape; [Greek: botrys], [Greek: + kampe] + +[112] _Phormobotrys_ = Grape basket; [Greek: phormos], [Greek: botrys]. + +[113] _Tripocalpis_ = Urn with three feet; [Greek: tripous], [Greek: + kalpis]. + +[114] _Tripodonium_ = Shell with three feet. + +[115] _Tripterocalpis_ = Urn with three wings; [Greek: tripteros], [Greek: + kalpis]. + +[116] _Trissopilium_ = Small hat with three wings; [Greek: trissos], + [Greek: pilion]. + +[117] _Archipilium_ = Primordial hat; [Greek: archipilion]. + +[118] _Tripilidium_ = Small hat with three feet; [Greek: tria], [Greek: + pilidion]. + +[119] _Tripodiscium_ = Shell with three small feet; [Greek: tria], [Greek: + podiskion]. + +[120] _Tridictyopus_ = Shell with three lattice-feet; [Greek: tria], + [Greek: diktyon], [Greek: pous]. + +[121] _Euscenium_ = Nice small tent; [Greek: eu], [Greek: skenion]. + +[122] _Cladoscenium_ = Small tent with branched axis; [Greek: klados], + [Greek: skenion]. + +[123] _Archiscenium_ = Primordial tent; [Greek: archi], [Greek: skenion]. + +[124] _Pteroscenium_ = Small tent with wings; [Greek: pteron], [Greek: + skenion]. + +[125] _Peridium_ = Small pouch; [Greek: peridion]. + +[126] _Archipera_ = Primordial pouch; [Greek: archi], [Greek: pera]. + +[127] _Archibursa_ = Primordial bottle; [Greek: archi], [Greek: byrsa]. + +[128] _Bathropyramis_ = Pyramid with ladders; [Greek: bathron], [Greek: + pyramis]. + +[129] _Cinclopyramis_ = Lattice-pyramid; [Greek: kinklis], [Greek: + pyramis]. + +[130] _Peripyramis_ = Pyramid with an envelope; [Greek: peri], [Greek: + pyramis]. + +[131] _Litharachnium_ = Spider-web of silex; [Greek: lithos], [Greek: + arachnion]. + +[132] _Cladarachnium_ = Spider-web with branched threads; [Greek: klados], + [Greek: arachnion]. + +[133] _Cystophormis_ = bladder-basket; [Greek: kyste], [Greek: phormis]. + +[134] _Haliphormis_ = Sea-basket; [Greek: hals], [Greek: phormis]. + +[135] _Archiphormis_ = Primordial-basket; [Greek: archi], [Greek: phormis]. + +[136] _Halicalyptra_ = Sea-veil; [Greek: hals], [Greek: kalyptra]. + +[137] _Carpocanistrum_ = Small fruit-basket; [Greek: karpos], [Greek: + kanistron]. + +[138] _Arachnocalpis_ = Urn enveloped by spider's web; [Greek: arachne], + [Greek: kalpis]. + +[139] _Phaenocalpis_ = Urceolate shell; [Greek: phaina], [Greek: kalpis]. + +[140] _Phaenoscenium_ = Tent-shaped shell; [Greek: phaina], [Greek: + skenion]. + +[141] _Calpophaena_ = Urceolate shell; [Greek: kalpis], [Greek: phaina]. + +[142] _Archiphaena_ = Primordial shell; [Greek: archi], [Greek: phaina]. + +[143] _Cornutella_ = Small horn; diminutive of cornu. + +[144] _Cornutanna_ = Horn-shaped; _Cornuta_. + +[145] _Archicorys_ = Principal helm; [Greek: archikorys]. + +[146] _Cyrtocalpis_ = Basket-urn or wicker-pitcher; [Greek: kyrtos], + [Greek: kalpis]. + +[147] _Mitrocalpis_ = Turban basket; [Greek: mitra], [Greek: kalpis]. + +[148] _Spongocyrtis_ = Spongy basket; [Greek: spongos], [Greek: kyrtis]. + +[149] _Halicapsa_ = Sea-capsule; [Greek: hals], [Greek: kapsa]. + +[150] _Archicapsa_ = Primordial capsule; [Greek: archikapsa]. + +[151] _Dictyophimus_ = Net goblet; [Greek: diktyon], [Greek: phimos]. + +[152] _Tripocyrtis_ = Basket with a tripod; [Greek: tripos], [Greek: + kyrtis]. + +[153] _Sethopilium_ = Small fenestrated hat; [Greek: setho], [Greek: + pilion]. + +[154] _Lithomelissa_ = Stone bee; [Greek: lithos], [Greek: melissa]. + +[155] _Psilomelissa_ = Smooth bee; [Greek: psilos], [Greek: melissa]. + +[156] _Spongomelissa_ = Spongy bee; [Greek: spongos], [Greek: melissa]. + +[157] _Clathrocanium_ = Basket of network; [Greek: klethra], [Greek: + kaneon]. + +[158] _Lamprodiscus_ = Splendid disk; [Greek: lampros], [Greek: diskos]. + +[159] _Lampromitra_ = Splendid turban; [Greek: lampros], [Greek: mitra]. + +[160] _Callimitra_ = Beautiful turban; [Greek: kallis], [Greek: mitra]. + +[161] _Clathromitra_ = Lattice-turban; [Greek: klethra], [Greek: mitra]. + +[162] _Clathrocorys_ = Lattice-helmet; [Greek: klethra], [Greek: korys]. + +[163] _Eucecryphalus_ = Nice net-cap, [Greek: eu], [Greek: kekryphalos]. + +[164] _Amphiplecta_ = Shell at both poles open, with framework around; + [Greek: amphiplekta]. + +[165] _Lychnocanium_ = Lantern-basket: [Greek: lychnos], [Greek: kaneon]. + +[166] _Lychnodictyum_ = Lantern with network; [Greek: lychnos], [Greek: + diktyon]. + +[167] _Sethopera_ = Sieve-pouch; [Greek: setho], [Greek: pera]. + +[168] _Lithopera_ = Stone-pouch; [Greek: lithos], [Greek: pera]. + +[169] _Micromelissa_ = Small bee; [Greek: mikros], [Greek: melissa]. + +[170] _Peromelissa_ = Pouch-bee; [Greek: pera], [Greek: melissa]. + +[171] _Sethomelissa_ = Sieve-bee; [Greek: setho], [Greek: melissa]. + +[172] _Tetrahedrina_ = Small tetrahedron; [Greek: tetraedron]. + +[173] _Sethochytris_ = Sieve-pot; [Greek: setho], [Greek: chytris]. + +[174] _Clathrolychnus_ = Fenestrated lantern; [Greek: klethra], [Greek: + lychnos]. + +[175] _Sethophormis_ = Sieve-basket; [Greek: setho], [Greek: phormis]. + +[176] _Sethamphora_ = Sieve-pitcher; [Greek: setho], [Greek: amphoreus]. + +[177] _Sethopyramis_ = Sieve-pyramid; [Greek: setho], [Greek: pyramis]. + +[178] _Plectopyramis_ = Woven pyramid; [Greek: plektos], [Greek: pyramis]. + +[179] _Spongopyramis_ = Spongy pyramid; [Greek: spongos], [Greek: pyramis]. + +[180] _Acanthocorys_ = Spiny Helmet; [Greek: akantha], [Greek: korys]. + +[181] _Arachnocorys_ = helmet with a cobweb; [Greek: arachne], [Greek: + korys]. + +[182] _Anthocyrtoma_ = Flower-arch; [Greek: anthos], [Greek: kyrtoma]. + +[183] _Anthocyrtis_ = Flower-basket; [Greek: anthos], [Greek: kyrtis]. + +[184] _Anthocyrtium_ = Flower-basket; [Greek: anthos], [Greek: kyrtion]. + +[185] _Anthocyrtidium_ = Small flower-basket; [Greek: anthos], [Greek: + kyrtidion]. + +[186] _Carpocanium_ = Fruit-basket; [Greek: karpos], [Greek: kaneon]. + +[187] _Sethophaena_ = Sieve-shell; [Greek: setho], [Greek: phaina]. + +[188] _Clistophaena_ = Closed shell; [Greek: kleistos], [Greek: phaina]. + +[189] _Sethoconus_ = Sieve-cone; [Greek: setho], [Greek: konos]. + +[190] _Periarachnium_ = Shell enveloped by cobweb; [Greek: peri], [Greek: + arachnion]. + +[191] _Sethocephalus_ = Sieve-head; [Greek: setho], [Greek: kephale]. + +[192] _Sethocyrtis_ = Sieve-basket; [Greek: setho], [Greek: kyrtis]. + +[193] _Sethocorys_ = Sieve-helmet; [Greek: setho], [Greek: korys]. + +[194] _Lophophaena_ = Shell with a top-knot; [Greek: lophos], [Greek: + phaino]. + +[195] _Dictyocephalus_ = Latticed head; [Greek: diktyon], [Greek: kephale]. + +[196] _Sethocapsa_ = Sieve-capsule; [Greek: setho], [Greek: kapsa]. + +[197] _Dicolocapsa_ = Two-jointed capsule; [Greek: dikolos], [Greek: + kapsa]. + +[198] _Cryptocapsa_ = Hidden capsule; [Greek: kryptos], [Greek: kapsa]. + +[199] _Pterocorys_ = Helmet with wings; [Greek: pteron], [Greek: korys]. + +[200] _Theopilium_ = Divine hat; [Greek: theos], [Greek: pilion]. + +[201] _Corocalyptra_ = Coif or hood of a girl; [Greek: kore], [Greek: + kalyptra]. + +[202] _Dictyoceras_ = Reticulated horn; [Greek: diktyon], [Greek: kera]. + +[203] _Pteropilium_ = Small hat with wings; [Greek: pteron], [Greek: + pilion]. + +[204] _Theopodium_ = Divine foot; [Greek: theos], [Greek: podion]. + +[205] _Pterocanium_ = Basket with wings; [Greek: pteron], [Greek: kaneon]. + +[206] _Pterocodon_ = Bell with wings; [Greek: pteron], [Greek: kodon]. + +[207] _Dictyocodon_ = Net-bell; [Greek: diktyon], [Greek: kodon]. + +[208] _Pleuropodium_ = Shell with ribs and feet; [Greek: pleura], [Greek: + podion]. + +[209] _Podocyrtis_ = Basket with feet; [Greek: pous], [Greek: kyrtis]. + +[210] _Thyrsocyrtis_ = Basket with a thyrsus or apical rod; [Greek: + thyrsos], [Greek: kyrtis]. + +[211] _Dictyopodium_ = Shell with latticed feet; [Greek: diktyon], [Greek: + podion]. + +[212] _Lithornithium_ = Siliceous bird; [Greek: lithos], [Greek: + ornithion]. + +[213] _Sethornithium_ = Latticed bird; [Greek: setho], [Greek: ornithion]. + +[214] _Theopera_ = Divine pouch; [Greek: theos], [Greek: pera]. + +[215] _Rhopalocanium_ = Basket with clubs; [Greek: rhopalon], [Greek: + kaneon]. + +[216] _Rhopalatractus_ = Spindle with clubs; [Greek: rhopalon], [Greek: + atraktos]. + +[217] _Lithochytris_ = Pot of silex; [Greek: lithos], [Greek: chytris]. + +[218] _Theophormis_ = Divine basket; [Greek: theos], [Greek: phormis]. + +[219] _Phormocyrtis_ = Plaited basket; [Greek: phormos], [Greek: kyrtis]. + +[220] _Alacorys_ = Wing-helmet. + +[221] _Cycladophora_ = Bearing a female robe; [Greek: kyklas], [Greek: + phoros]. + +[222] _Calocyclas_ = Beautiful female robe; [Greek: kalos], [Greek: + kyklas]. + +[223] _Clathrocyclas_ = Fenestrated female robe; [Greek: klethra], [Greek: + kyklas]. + +[224] _Lamprocyclas_ = Splendid female robe; [Greek: lampros], [Greek: + kyklas]. + +[225] _Diplocyclas_ = Female robe with a double girdle; [Greek: diploos], + [Greek: kyklas]. + +[226] _Hexalatractus_ = Spindle with six wings; [Greek: hexala], [Greek: + atraktos]. + +[227] _Theophaena_ = Divine shell; [Greek: theos], [Greek: phaina]. + +[228] _Theocalyptra_ = Divine veil; [Greek: theos], [Greek: kalyptra]. + +[229] _Cecryphalium_ = Net-cap; [Greek: kekryphalion]. + +[230] _Theoconus_ = Divine cone; [Greek: theos], [Greek: konos]. + +[231] _Lophoconus_ = Cone with a crest; [Greek: lophos], [Greek: konos]. + +[232] _Theocyrtis_ = Divine basket; [Greek: theos], [Greek: kyrtis]. + +[233] _Theosyringium_ = Divine tube; [Greek: theos], [Greek: syringion]. + +[234] _Lophocyrtis_ = Basket with a crest; [Greek: lophos], [Greek: + kyrtis]. + +[235] _Tricolocampe_ = Caterpillar with three joints; [Greek: tris], + [Greek: kolon], [Greek: kampe]. + +[236] _Theocorys_ = Divine helmet; [Greek: theos], [Greek: korys]. + +[237] _Axocorys_ = Helmet with an internal axis; [Greek: axis], [Greek: + korys]. + +[238] _Lophocorys_ = Helmet with a top crest; [Greek: lophos], [Greek: + korys]. + +[239] _Theocampe_ = Divine caterpillar; [Greek: theos], [Greek: kampe]. + +[240] _Theocapsa_ = Divine capsule; [Greek: theos], [Greek: kapsa]. + +[241] _Tricolocapsa_ = Three-jointed capsule; [Greek: trikolon], [Greek: + kapsa]. + +[242] _Phrenocodon_ = Bell with diaphragm; [Greek: phren], [Greek: kodon]. + +[243] _Stichopilium_ = Hat with a row of joints; [Greek: stichos], [Greek: + pilion]. + +[244] _Artopilium_ = Loaf-hat; [Greek: artos], [Greek: pilion]. + +[245] _Pteropilium_ = Winged hat; [Greek: pteron], [Greek: pilion]. + +[246] _Stichocampe_ = Caterpillar with a row of joints; [Greek: stichos], + [Greek: kampe]. + +[247] _Stichopterium_ = Row-wing; [Greek: stichos], [Greek: pterion]. + +[248] _Podocampe_ = Caterpillar with feet; [Greek: pous], [Greek: kampe]. + +[249] _Stichopodium_ = Row-foot; [Greek: stichos], [Greek: podion]. + +[250] _Stichopera_ = Row-pouch; [Greek: stichos], [Greek: pera]. + +[251] _Cyrtopera_ = Basket-pouch; [Greek: kyrtos], [Greek: pera]. + +[252] _Artopera_ = Bread-pouch; [Greek: artos], [Greek: pera]. + +[253] _Stichophormis_ = Row-basket; [Greek: stichos], [Greek: phormis]. + +[254] _Phormocampe_ = Latticed caterpillar; [Greek: phormos], [Greek: + kampe]. + +[255] _Artophormis_ = Bread-basket; [Greek: artos], [Greek: phormis]. + +[256] _Cyrtophormis_ = Plaited-basket; [Greek: kyrtos], [Greek: phormis]. + +[257] _Artophaena_ = Bread-shell; [Greek: artos], [Greek: phaina]. + +[258] _Stichophaena_ = Row-shell; [Greek: stichos], [Greek: phaina]. + +[259] _Lithostrobus_ = Cone of silex; [Greek: lithos], [Greek: strobos]. + +[260] _Dictyomitra_ = Net-cap; [Greek: diktyon], [Greek: mitra]. + +[261] _Stichocorys_ = Row-helmet; [Greek: stichos], [Greek: korys]. + +[262] _Artostrobus_ = Bread-cone; [Greek: artos], [Greek: strobos]. + +[263] _Lithomitra_ = Stone-cap; [Greek: lithos], [Greek: mitra]. + +[264] _Eucyrtidium_ = Nice small basket; [Greek: eu], [Greek: kyrtidion]. + +[265] _Eusyringium_ = Nice small tube; [Greek: eu], [Greek: syringion]. + +[266] _Siphocampe_ = Caterpillar with a tube; [Greek: siphon], [Greek: + kampe]. + +[267] _Lithocampe_ = Stone-caterpillar; [Greek: lithos], [Greek: kampe]. + +[268] _Spirocyrtis_ = Spiral basket; [Greek: speira], [Greek: kyrtis]. + +[269] _Spirocampe_ = Spiral caterpillar; [Greek: speira], [Greek: kampe]. + +[270] _Cyrtocapsa_ = Basket-capsule; [Greek: kyrtos], [Greek: kapsa]. + +[271] _Stichocapsa_ = Jointed capsule; [Greek: stichos], [Greek: kapsa]. + +[272] _Artocapsa_ = Bread-shaped capsule; [Greek: artos], [Greek: kapsa]. + +[273] Ueber die Phaeodarien, eine neue Gruppe kieselschaliger mariner + Rhizopoden, _Sitzungsb. med.-nat. Gesellsch. Jena_, December 12, + 1879, pp. 3, 4. + +[274] _Phaeocolla_ = Brown jelly; [Greek: phaios], [Greek: kolla]. + +[275] _Phaeodina_ = Provided with brown pigment; [Greek: phaiodion]. + +[276] _Cannobelos_ = Bearing hollow tubular arrows; [Greek: kanna], [Greek: + belos]. + +[277] _Cannorrhaphis_ = Bearing hollow tubular needles; [Greek: kanna], + [Greek: rhaphis]. + +[278] _Catinulus_ = Small cup or dish. + +[279] _Mesocena_ = Hollow in the centre, annular; [Greek: meson], [Greek: + kenos]. + +[280] _Dictyocha_ = Net-possessing; [Greek: diktyon], [Greek: echo]. + +[281] _Distephanus_ = Double corona; [Greek: distephanos]. + +[282] _Cannopilus_ = Hat with tubes; [Greek: kanna], [Greek: pilos]. + +[283] _Aulactinium_ = With radial tubes; [Greek: aulos], [Greek: achtis]. + +[284] _Aulacantha_ = Tubular spine; [Greek: aulos], [Greek: akantha]. + +[285] _Aulographis_ = Tubular style; [Greek: aulos], [Greek: graphis]. + +[286] _Auloceros_ = Tubular horn; [Greek: aulos], [Greek: keros]. + +[287] _Aulospathis_ = Tube with whirls; [Greek: aulos], [Greek: spathis]. + +[288] _Aulodendron_ = Tubular tree; [Greek: aulos], [Greek: dendron]. + +[289] _Orona_ = Hilly or tuberculate shell; [Greek: oros], [Greek: one]. + +[290] _Orosphaera_ = Sphere with hilly elevation; [Greek: oros], [Greek: + sphaira]. + +[291] _Oroscena_ = Shell with tent-shaped elevations; [Greek: oros], + [Greek: skene]. + +[292] In the plate the number is omitted by mistake. The figure is above in + the middle. + +[293] _Oroplegma_ = Hilly shell of framework; [Greek: oros], [Greek: + plegma]. + +[294] _Sagena_ = Drag-net; [Greek: sagene]. + +[295] _Sagosphaera_ = Spherical armour; [Greek: sage], [Greek: sphaira]. + +[296] _Sagoscena_ = Armour with tents; [Greek: sage], [Greek: skene]. + +[297] _Sagenoscena_ = Net with tents; [Greek: sagene], [Greek: skene]. + +[298] _Sagmarium_ = Covering of a shield, armour; [Greek: sagmarion]. + +[299] _Sagmidium_ = Small armour, military clock; [Greek: sagmidion]. + +[300] _Sagoplegma_ = Armour of framework; [Greek: sage], [Greek: plegma]. + +[301] _Aularia_ = Tubular shell; [Greek: aularia]. + +[302] _Aulosphaera_ = Tubular sphere; [Greek: aulos], [Greek: sphaira]. + +[303] _Auloscena_ = Tubular tent; [Greek: aulos], [Greek: skene]. + +[304] _Auloplegma_ = Tubular framework; [Greek: aulos], [Greek: plegma]. + +[305] _Aulophacus_ = Tubular lens; [Greek: aulos], [Greek: phakos]. + +[306] _Aulatractus_ = Spindle composed of tubes; [Greek: aulos], [Greek: + atraktos]. + +[307] _Aulonia_ = Tubular object; [Greek: aulos], [Greek: onion]. + +[308] _Aulastrum_ = Tubular star; [Greek: aulos], [Greek: astron]. + +[309] _Aulodictyum_ = Tubular net; [Greek: aulos], [Greek: diktyon]. + +[310] _Cannosphaera_ = Sphere with tubules; [Greek: kanna], [Greek: + sphaira]. + +[311] _Coelacantha_ = Hollow spine; [Greek: koilos], [Greek: akantha]. + +[312] _Lithogromia_ = Siliceous _Gromia_. + +[313] _Entocannula_ Shell with an internal tube. + +[314] _Pharyngella_ = Shell with an internal pharynx. + +[315] _Porcupinia_, in memory of H.M.S. "Porcupine" by which the first + British deep-sea explorations were carried out during the years 1869 + and 1870. + +[316] _Cortinetta_ = Diminutive of _Cortina_. + +[317] _Medusetta_ = Small Medusa. + +[318] _Euphysetta_ = Diminutive of _Euphysa_ (a Medusa). + +[319] _Gazelletta_ = Named in memory of the German ship "Gazelle," which + was engaged in deep-sea soundings during the years 1874 to 1876, + under the command of Captain Schleinitz (Naturalist, Professor + Studer). + +[320] _Gorgonetta_ = Diminutive of _Gorgo_, Medusa. + +[321] _Polypetta_ = Diminutive of _Polypus_. + +[322] _Castanarium_ = Shell similar to a chestnut, _Castanea_. + +[323] _Castanella_ = Diminutive of _Castanea_. + +[324] _Castanidium_ = Small chestnut; [Greek: kastanidion]. + +[325] _Castanissa_ = Diminutive of _Castanea_. + +[326] _Castanopsis_ = Shell similar to a chestnut; [Greek: kastanon], + [Greek: opsis]. + +[327] _Castanura_ = Chestnut with tails; [Greek: kastanon], [Greek: oura]. + +[328] _Circoporus_ = Shell with circles of pores; [Greek: kirkos], [Greek: + poros]. + +[329] _Circospathis_ = Shell with verticils around the spines; [Greek: + kirkos], [Greek: spathis]. + +[330] _Circogonia_ = Polyhedron with circles of pores; [Greek: kirkos], + [Greek: gonia]. + +[331] _Circorrhegma_ = Shell with circles of fissures; [Greek: kirkos], + [Greek: rhegma]. + +[332] _Circostephanus_ = Shell with circular coronets; [Greek: kirkos], + [Greek: stephanos]. + +[333] _Tuscarora_, named from the American ship "Tuscarora," commanded by + Captain Belknap, which made a splendid series of deep-sea soundings + in the Pacific Ocean in 1875. + +[334] _Tuscarusa_, derivation from _Tuscarora_. + +[335] _Tuscaridium_, derivation from _Tuscarora_. + +[336] _Concharium_ = Small mussel; [Greek: koncharion]. + +[337] _Conchasma_ = Bivalved shell-fish; [Greek: konchasma]. + +[338] _Conchellium_ = Small bivalved mussel; [Greek: konchellion]. + +[339] _Conchidium_ = Similar to a bivalved mollusc; [Greek: konchidion]. + +[340] _Conchonia_ = Bivalved shell like a mussel; [Greek: konche], [Greek: + onia]. + +[341] _Conchopsis_ = Similar to a bivalved shell-fish or mussel; [Greek: + konche], [Greek: opsis]. + +[342] _Conchoceras_ = Mussel with horns; [Greek: konche], [Greek: keras]. + +[343] _Coelodoras_ = Hollow spear; [Greek: koilos], [Greek: doras]. + +[344] _Coelodendrum_ = Hollow tree; [Greek: koilos], [Greek: dendron]. + +[345] _Coelodrymus_ = Forest of hollow trees, [Greek: koilos], [Greek: + drymos]. + +[346] _Coelodasea_ = Hollow thicket, [Greek: koilos], [Greek: dasea]. + +[347] _Coelotholus_ = Hollow cupola; [Greek: koilos], [Greek: tholos]. + +[348] _Coelothauma_ = Hollow wonder; [Greek: koilos], [Greek: thauma] + +[349] _Coelothamnus_ = Hollow thicket; [Greek: koilos], [Greek: thamnos] + +[350] _Coelographis_ = Hollow style; [Greek: koilos], [Greek: graphis]. + +[351] _Coelospathis_ = Hollow whorl; [Greek: koilos], [Greek: spathis]. + +[352] _Coelodecas_ = Shell with ten hollow styles; [Greek: koilos], [Greek: + dekas]. + +[353] _Coelostylus_ = Hollow style; [Greek: koilos], [Greek: stylos]. + +[354] _Coeloplegma_ = Hollow framework; [Greek: koilos], [Greek: plegma]. + +[355] _Coelagalma_ = Hollow ornament: [Greek: koilos], [Greek: agalma]. + + + + + * * * * * + + + + +Corrections made to printed text + +Page 920: (The different genera of) 'Plectanida' corrected from +'Plectonida'. + +Page 951, Cortina dendroides, feet: '0.15 to 0.2' corrected from '01.5 to +0.2'. + +Page 964, Cortiniscus tetrapylaris, height: '0.08 to 0.12' corrected from +'0.08 to 0.012'. + +Page 1029, Tripospyris furcata: (Facial and occipital) 'plates' corrected +from 'faces' (as adjoining species). + +Page 1056, Elaphospyris heptaceros, horns: '0.08' corrected from '0.008' +("as long as the shell"). + +Page 1069, Ceratospyris ramosa, author: 'Ceratospyris' corrected from +'Ceratopyris'. + +Page 1138, Tripterocalpis, definition: 'Tripocalpis' corrected from +'Tripodocalpis'. + +Page 1181, Cornutella stiligera, dimensions: '0.03 to 0.04 broad' corrected +from '0.03 to 0.04 long' (as adjoining species). + +Page 1220, Clathrocorys murrayi, thorax length: '0.04' corrected from +'0.0.04'. + +Page 1237, Peromelissa calva, thorax length: '0.07' corrected from '0.7' +("little larger than the cephalis"). + +Page 1260, Plectopyramis polypleura, thorax: '0.24 broad' corrected from +'0.24 long' (as adjoining species). + +Page 1338, Podocyrtis conica, breadth a: '0.03' corrected from '00.3'. + +Page 1343, Podocyrtis hexagonalis, breadth b: '0.11' corrected from +'0.011'. + +Page 1352, Dictyopodium eurylophus, author: 'Dictyopodium' corrected from +'Dictopodium'. + +Page 1355, Lithornithium trochilus, length (b): '0.05' corrected from +'0.5'. + +Page 1378, Cycladophora enneapleura: 'Cycladophora gigas' corrected from +'Clycladophora gigas'. + +Page 1385, Calocyclas monumentum, length (c): '0.06' corrected from '0.6'. + +Page 1387, Clathrocyclas domina: 'peristome' corrected from 'persistome'. + +Page 1397, Theocalyptra veneris: 'Eucecryphalus' corrected from +'Eucephryphalus'. + +Page 1415, Theocorys turgidula, length (b): '0.05' corrected from '0.005'. + +Page 1415, Theocorys cretica, length (a): '0.02' corrected from '0.2'. + +Page 1417, Eucyrtidium attenuatum, dimensions: 'breadth' inserted. + +Page 1444, Stichocampe convergens, length of each joint: '0.035' corrected +from '0.35'. + +Page 1547, first paragraph: 'Thalassoplancta' corrected from +'Thallassoplancta'. + +Page 1555, Mesocena diodon: 'Ehrenberg, 1854' corrected from 'Ebrenberg, +1854'. + +Page 1572, The distal ends of the radial tubes: 'Auloceros' corrected from +'Auloceras'. + +Ib., The central capsule: 'Aulosphaerida' corrected from 'Aulasphaerida'. + +Page 1573, second paragraph: 'Thalassicolla nucleata' corrected from +'Thallassicolla nucleata'. + +Page 1574, first paragraph: 'Aulographida' corrected from 'Aulagraphida'. + +Page 1591, The lattice-shell: 'Cenosphaera' corrected from 'Cenosphera'. + +Page 1593, Orosphaerida, central capsule: (rarely less than) '0.12' +corrected from '1.2'. + +Page 1595, Orosphaera foveolata, length of spines: '0.5' corrected from +'0.05' ("half as long as the radius of the shell"). + +Page 1607, Sagosphaera penicilla, reference to 'Sagenoscena penicillata' +corrected from 'Sagenoscena pencillata'. + +Page 1658, Challengeron moseleyi, larger spines: '0.06' corrected from +'0.6' ("about as long as the radius"). + +Page 1663, Porcupinia aculeata: 'Pharynx' corrected from 'Pharnyx'. + +Page 1744, The maximum number of tubes: first occurence of 'Coeloplegmida' +corrected from 'Coloeplegmida'. + +Index: 'Acrocoronis' corrected from 'Acrocoronia'. + +Index, Alacorys: 'guilelmi' corrected from 'gulielmi'. + +Index, Amphicraspedum: 'maclaganium' corrected from 'maclagganium' (per +text). + +Index, Archidiscus: 'dithalamus' corrected from 'dithalamius', and +'trithalamus' from 'trithalamius' (per text). + +Index: 'Aulographantha' corrected from 'Aulographanta'. + +Index, Aulosphaera diodon: '1623' corrected from '1523'. + +Index, Calocyclas amicae: '1382' corrected from '1282'. + +Index, Calocyclas: 'aspasia' corrected from 'aspasiae'. + +Index: 'Conarachnium' corrected from 'Conarachinum'. + +Index, Cyphinus: 'dixiphus' corrected from 'dixiphos' (per text). + +Index, Hexacolpus: 'dodecodus' corrected from 'dodecotus', per text as +signifying 12 teeth (odos). + +Index, Lithobotrys galea: '1123' corrected from '1128'. + +Index, Panartus profundissimus: '380' corrected from '880'. + +Index: 'Phacodiscida' corrected from 'Phacodisida'. + +Index, Pityomma: '259' corrected from '299'. + +Index, Pylonium nephropylium: '655' corrected from '955'. + +Index: 'Sethopera' corrected from 'Sethoptera' + +Index, Spongellipsis: '341' corrected from '34'. + +Index, Spongocore: 'diplocylindrica' corrected from 'diplocylindrus' (per +text). + +Index, Aulosphaera diodon: '578' corrected from '378'. + +Index, Spongostylus: '149' corrected from '749'. + +Index: 'Staurocyclia' corrected from 'Staurocylia'. + +Index, Stichoperida: '1447' corrected from '1147'. + +Index, Theocampe: 'gemmata' corrected from 'geminata'. + +Index, Tuscarora: 'cygnea' corrected from 'cygneum'. + +Footnote 188: '[Greek: kleistos]' corrected from '[Greek: setho]' (carried +down from previous footnote). + +Footnote 308: 'Aulastrum' corrected from 'Aulastrus'. + + + +***END OF THE PROJECT GUTENBERG EBOOK REPORT ON THE RADIOLARIA COLLECTED +BY H.M.S. CHALLENGER DURING THE YEARS 1873-1876, SECOND PART: SUBCLASS +OSCULOSA; INDEX*** + + +******* This file should be named 44526.txt or 44526.zip ******* + + +This and all associated files of various formats will be found in: +http://www.gutenberg.org/dirs/4/4/5/2/44526 + + + +Updated editions will replace the previous one--the old editions +will be renamed. + +Creating the works from public domain print editions means that no +one owns a United States copyright in these works, so the Foundation +(and you!) can copy and distribute it in the United States without +permission and without paying copyright royalties. Special rules, +set forth in the General Terms of Use part of this license, apply to +copying and distributing Project Gutenberg-tm electronic works to +protect the PROJECT GUTENBERG-tm concept and trademark. Project +Gutenberg is a registered trademark, and may not be used if you +charge for the eBooks, unless you receive specific permission. 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