Add files from ibiblio as of 2025-03-07 13:37:39HEADmain

1 files changed, 3707 insertions, 0 deletions

diff --git a/43928-0.txt b/43928-0.txt
new file mode 100644
index 0000000..e184956
--- /dev/null
+++ b/43928-0.txt
@@ -0,0 +1,3707 @@
+*** START OF THE PROJECT GUTENBERG EBOOK 43928 ***
+
+Transcriber's Note: Italic text is denoted by _underscores_ and bold
+text by =equal signs=.
+
+
+
+
+THE BRITISH WOODLICE.
+
+
+
+
+This monograph first appeared in the "Essex Naturalist" (Volume XIV.,
+1905-6) and has been republished by special arrangement with the
+Council of the Essex Field Club.
+
+
+
+
+THE BRITISH WOODLICE.
+
+BEING
+
+A MONOGRAPH OF THE TERRESTRIAL ISOPOD CRUSTACEA
+
+OCCURRING IN THE BRITISH ISLANDS.
+
+BY
+
+WILFRED MARK WEBB, F.L.S.,
+
+_Lecturer on Biology and Nature Study to the Surrey County Council,
+Honorary Secretary of the Selborne Society, Sometime, Senior Assistant
+Lecturer on Biology to the Essex County Council, and Editor of the
+Journal of Malacology, Joint Author of_ "Eton Nature Study and
+Observational Lessons."
+
+AND
+
+CHARLES SILLEM.
+
+WITH TWENTY-FIVE PLATES AND FIFTY-NINE FIGURES IN THE TEXT.
+
+  LONDON:
+  DUCKWORTH & CO.,
+  3, HENRIETTA STREET, COVENT GARDEN.
+  1906.
+
+
+
+
+PREFACE.
+
+
+In Professor Sars' "Crustacea of Norway," quite a number of the British
+species of woodlice are figured in detail and described in English, but
+few copies of this fine work are to be met with in our country. The
+Rev. Canon Norman has from time to time published notes on the British
+species in "The Annals and Magazine of Natural History;" these are,
+however, scattered, and contain but few figures, while other literature
+that exists is out of date. Under these circumstances, we have thought
+that the following account and figures of all the British species would
+be useful to those anxious to work at the woodlice, and might also
+encourage others to pay attention to the distribution and habits of the
+interesting tribe to which they belong.
+
+The writers would welcome any corrections or additions in view of a
+second edition.
+
+    W.M.W.
+    C.S.
+
+ODSTOCK, HANWELL, _December, 1905_.
+
+
+
+
+CONTENTS.
+
+
+                                                                 PAGE
+
+  Introduction                                                     1
+  Geological history                                               1
+  External structure and appendages                                2
+  Alimentary canal                                                 6
+  Circulatory system                                               7
+  Excretory system                                                 7
+  Nervous system                                                   8
+  Reproductive organs                                              8
+  Development                                                      9
+  Habits and Economic considerations                               12
+  Local names                                                      15
+  Methods of collections and preservation                          16
+  Classification                                                   17
+  Scheme of classification and synopsis of generic characters      18
+  British Species                                                  19
+  Section--Ligiæ                                                   19
+  Family--Ligiidæ                                                  19
+  Genus--Ligia Fabricius                                           19
+  _Ligia oceanica_ Linzé                                           19
+  Genus--Ligidium Brandt                                           21
+  _Ligidium hypnorum_ Cuvier                                       21
+  Family--Trichoniscidæ                                            22
+  Genus--Trichoniscus Brandt                                       22
+  _Trichoniscus pusillus_ Brandt                                   22
+  _Trichoniscus vividus_ Koch                                      23
+  _Trichoniscus roseus_ Koch                                       24
+  Genus--Trichoniscoides, Sars                                     25
+  _Trichoniscoides albidus_ Budde-Lund                             25
+  Genus--Haplophthalmus Schobl                                     26
+  _Haplophthalmus mengii_ Zaddach                                  26
+  _Haplophthalmus danicus_ Budde-Lund                              27
+  Family--Oniscidæ                                                 27
+  Genus--Oniscus Linné                                             27
+  _Oniscus asellus_ Linné                                          27
+  Genus--Philoscia Latreille                                       29
+  _Philoscia muscorum_ Scopoli                                     29
+  _Philoscia couchii_ Kinahan                                      30
+  Genus--Platyarthrus Brandt                                       30
+  _Platyarthrus hoffmannseggii_ Brandt                             30
+  Genus--Porcellio Latreille                                       32
+  _Porcellio scaber_ Latreille                                     32
+  _Porcellio pictus_ Brandt and Ratzeburg                          33
+  _Porcellio dilatatus_ Brandt                                     33
+  _Porcellio rathkei_ Brandt                                       34
+  _Porcellio laevis_ Latreille                                     35
+  _Porcellio ratzeburgii_ Brandt                                   36
+  Genus--Metoponorthus Budde-Lund                                  37
+  _Metoponorthus pruinosus_ Brandt                                 37
+  _Metoponorthus cingendus_ Kinahan                                38
+  Genus--Cylisticus Schnitzler                                     38
+  _Cylisticus convexus_ De Geer                                    39
+  Family--Armadillidiidæ                                           40
+  Genus--Armadillidium Brandt                                      40
+  _Armadillidium nasatum_ Budde-Lund                               40
+  _Armadillidium vulgare_ Latreille                                41
+  _Armadillidium pulchellum_ Zencker                               42
+  _Armadillidium depressum_ Brandt                                 43
+  Distribution of species                                          43
+  Conclusion                                                       43
+  Bibliography                                                     49
+
+
+
+
+LIST OF FIGURES.
+
+
+PLATES I.-XXV. with a List, will be found at the end of the Book.
+
+
+FIGURE.                                                          PAGE.
+
+  1. Parts of the body (_Oniscus asellus_)                         2
+  2. The first antenna (_Oniscus asellus_)                         2
+  3. The second antenna (_Oniscus asellus_)                        3
+  4. The underside of the head (_Oniscus asellus_)                 3
+  5. The mandibles (_Oniscus asellus_)                             4
+  6. The first maxillae (_Oniscus asellus_)                        4
+  7. The second maxillae (_Oniscus asellus_)                       4
+  8. The fused maxillipeds (_Oniscus asellus_)                     4
+  9. The "upper lip" (_Oniscus asellus_)                           5
+  10. The "lower lip" (_Oniscus asellus_)                          5
+  11. A typical thoracic segment (_Oniscus asellus_)               5
+  12. The fifth thoracic segment of a female
+        (_Oniscus asellus_)                                        5
+  13. The underside of the abdomen of a female
+        (_Oniscus asellus_)                                        6
+  14. A typical abdominal appendage
+        (_Oniscus asellus_)                                        6
+  15. The first abdominal appendage of the male
+        (_Oniscus asellus_)                                        6
+  16. The second abdominal appendage of the male
+        (_Oniscus asellus_)                                        6
+  17. The alimentary canal (_Oniscus asellus_)                     7
+  18. The circulatory system (_Oniscus asellus_)                   7
+  19. The nervous system (_Oniscus asellus_)                       8
+  20. Female reproductory organs (_Oniscus asellus_)               8
+  21. The male reproductory organs (_Oniscus asellus_)             9
+  22. The fertilized egg (_Porcellio scaber_) after Roule         10
+  23. The fertilized egg seen in section
+        (_Porcellio scaber_) after Roule                          10
+  24 to 31. The development of a woodlouse
+        (_Porcellio scaber_) after Roule                          10
+  32. Embryo of the woodlouse showing the three divisions of the
+        intestine separately developed (_Porcellio scaber_)
+        after Roule                                               11
+  33. Embryo of the woodlouse showing traces of the segments
+        (_Porcellio scaber_) after Roule                          11
+  34. An embryo woodlouse ready to be hatched
+        (_Porcellio scaber_) after Roule                          11
+  35. Flagellum and last peduncular joint of the antenna of
+        _Ligia oceanica_                                          12
+  36. Flagellum and last peduncular joint of the antenna of
+        _Ligidium hypnorum_                                       13
+  37. Flagellum and last peduncular joint of the antenna of
+        _Trichoniscus pusillus_                                   23
+  38. Flagellum and last peduncular joint of the antenna of
+        _Trichoniscus vividus_                                    24
+  39. Flagellum and last peduncular joint of the antenna of
+        _Trichoniscus roseus_                                     24
+  40. Flagellum and last peduncular joint of the antenna of
+        _Trischoniscoides albidus_                                25
+  41. Flagellum and last peduncular joint of the antenna of
+        _Haplophthalmus mengii_                                   26
+  42. Flagellum and last peduncular joint of the antenna of
+        _Haplophthalmus danicus_                                  27
+  43. Flagellum and last peduncular joint of the antenna of
+        _Oniscus asellus_                                         28
+  44. Flagellum and last peduncular joint of the antenna of
+        _Philoscia muscorum_                                      29
+  45. Flagellum and last peduncular joint of the antenna of
+        _Philoscia couchii_                                       30
+  46. Flagellum and last peduncular joint of the antenna of
+        _Platyarthrus hoffmannseggii_                             31
+  47. Flagellum and last peduncular joint of the antenna of
+        _Porcellio scaber_                                        32
+  48. Flagellum and last peduncular joint of the antenna of
+        _Porcellio pictus_                                        33
+  49. Flagellum and last peduncular joint of the antenna of
+        _Porcellio dilatatus_                                     34
+  50. Flagellum and last peduncular joint of the antenna of
+        _Porcellio rathkei_                                       35
+  51. Flagellum and last peduncular joint of the antenna of
+        _Porcellio laevis_                                        35
+  52. Flagellum and last peduncular joint of the antenna of
+        _Porcellio ratzeburgii_                                   36
+  53. Flagellum and last peduncular joint of the antenna of
+        _Metoponorthus pruinosus_                                 37
+  54. Flagellum and last peduncular joint of the antenna of
+        _Metoponorthus cingendus_                                 38
+  55. Flagellum and last peduncular joint of the antenna of
+        _Cylisticus convexus_                                     39
+  56. Flagellum and last peduncular joint of the antenna of
+        _Armadillidium nasatum_                                   40
+  57. Flagellum and last peduncular joint of the antenna of
+        _Armadillidium vulgare_                                   41
+  58. Flagellum and last peduncular joint of the antenna of
+        _Armadillidium pulchellum_                                42
+  59. Flagellum and last peduncular joint of the antenna of
+        _Armadillidium depressum_                                 43
+
+
+
+
+THE BRITISH WOODLICE.
+
+
+=Introduction.=--Having finished a somewhat exhaustive list of the land
+and fresh-water molluscs of Essex,[1] one of the present writers felt
+that if he were to make any further contributions of importance to a
+knowledge of the fauna of that interesting county, he must turn his
+attention to some other group of animals. It seemed most fitting that
+some creatures should be chosen which are commonly met with during the
+search for molluscs. Centipedes, millepedes, and woodlice fulfilled
+these conditions, and all were collected, but as only seventeen
+species of woodlice had at the time been found in England, it was
+deemed advisable to study these in detail to begin with. The present
+contribution is the result of the undertaking, and we have thought that
+a general consideration of the British Woodlice, with careful drawings
+from nature of all the species now known from this country, ought to
+lead to a more general study of these interesting creatures and their
+habits.
+
+=Position in the scheme of classification.=--The Woodlice belong to
+an immense group of invertebrate animals known as the Arthropoda, the
+bodies of which are segmented and provided with jointed appendages for
+purposes of walking, swimming, and feeding. Of this group, two large
+divisions are recognized. The first contains the forms which breathe
+by means of air-tubes, such as the Insects; and the second has been
+constituted for Crustacea, which breathe by means of gills. The latter
+are, of course, adapted more especially for a life in water, but here
+and there we come across examples so modified that they can exist in
+air. The land-crabs are a case in point, and so are the Woodlice. These
+belong to an order which contains many fresh-water and marine species,
+known as the Isopoda.
+
+=Geological history.=--The known history of the order is a long one,
+for remains occur in the Old Red Sandstone (Devonian) of Herefordshire,
+and in the Coal Measures. (79)[2]. A form which has been named
+_Archæoniscus brodiei_, and is said to be referable to the recent
+family Aegidae which is found in some numbers in the Purbeck Beds
+(Upper Jurassic), of this country (47). Fossil Isopods have also been
+recorded from the Oolite and from the Oligocene (Isle of Wight).
+
+Turning to the Woodlice proper, we find that they first make their
+appearance in the Miocene (of Oenigen and Baden), and occur also
+in amber (79); while examples of genera, such as _Oniscus_ and
+_Porcellio_, have been discovered in late Tertiary deposits (47).
+
+=External structure and appendages.=--Woodlice agree in being of a
+somewhat oval form, and their bodies are arched, the curve varying in
+different genera and species. A _head_ is to be distinguished; behind
+this comes the _thorax_ of seven segments which are often considerably
+broader than the six succeeding ones which form the _abdomen_ (see fig.
+1.)
+
+[Illustration: FIG. 1.--PARTS OF THE BODY. (_Oniscus asellus._)]
+
+The head carries two _large antennae_ (fig. 3) which are very evident,
+and a careful search with a lens will reveal a second and minute pair
+(the _smaller antennae_) situated between the base of the others, and
+really anterior to them. (figs. 2 and 4.)
+
+[Illustration: FIG. 2.--THE FIRST ANTENNA. (_Oniscus asellus._)]
+
+The larger antennae are customarily bent at certain points, and we can
+distinguish a terminal part, or _flagellum_, and a basal part, the
+_peduncle_ (fig. 3). The number of joints in these structures, which
+varies in different genera and species, forms a useful classificatory
+character, and the relative length of the component parts is of
+considerable value in distinguishing species.
+
+[Illustration: FIG. 3.--THE SECOND ANTENNA. (_Oniscus asellus._)]
+
+There are four pairs of mouth appendages--namely the jaws or
+_mandibles_ (fig. 5), the _first maxillae_ (fig. 6), the _second
+maxilla_ (fig. 7), and the _maxillipeds_ (fig. 8). When the head is
+examined from the underside the last of these organs will be seen
+first, covering in the others.
+
+[Illustration: FIG. 4.--THE UNDERSIDE OF THE HEAD. (_Oniscus
+asellus._)]
+
+A small median plate attached to the front of the head has been called
+"_the upper lip_" (fig. 9), while inside the mouth appendages is a
+little bilobed structure "_the lower lip_" (fig. 10).
+
+[Illustration: FIG. 5.--THE MANDIBLES. (_Oniscus asellus._)]
+
+Before leaving the external features of the head, we must allude to
+the pair of _eyes_ which are usually present, though never raised on
+stalks. In the Common Woodlouse (_Oniscus asellus_, from which all
+our figures to illustrate structure have been made), as in many other
+species, the eyes are compound (fig. 4), but in some forms these are
+simple.
+
+[Illustration: FIG. 6.--THE FIRST MAXILLAE. (_Oniscus asellus._)]
+
+[Illustration: FIG. 7.--THE SECOND MAXILLAE. (_Oniscus asellus._)]
+
+[Illustration: FIG. 8.--THE FUSED MAXILLIPEDS. (_Oniscus asellus._)]
+
+Each of the seven joints of the thorax bears a pair of _walking legs_
+(fig. 11), and in the female at the time when the eggs are laid, a pair
+of plates (fig. 12) arises on segments II. to V. These plates together
+form a brood pouch, in which the eggs are carried (fig. 12) until
+they are hatched, and in which the young ones remain for some time
+afterwards.
+
+When we examine the abdomen, we find that the appendages are
+plate-like, with the exception of the last pair (fig. 13), and they all
+agree in having two divisions, an arrangement which would prove awkward
+in limbs used for walking or feeling.
+
+[Illustration: FIG. 9.--THE "UPPER LIP." (_Oniscus asellus._)]
+
+[Illustration: FIG. 10.--THE "LOWER LIP." (_Oniscus asellus._)]
+
+[Illustration: FIG. 11.--A TYPICAL THORACIC SEGMENT. (_Oniscus
+asellus._)]
+
+[Illustration: FIG. 12.--THE FIFTH THORACIC SEGMENT OF A FEMALE.
+(_Oniscus asellus._)]
+
+The inner plate (or endopodite) is in structure a _gill_, but the blood
+that passes through it, is enabled to take up oxygen from moist air,
+while the outer division (or exopodite) acts as a protecting cover
+(fig. 14). In _Porcellio_, air-tubes (_tracheae_) may be present (see
+below).
+
+[Illustration: FIG. 13.--THE UNDERSIDE OF THE ABDOMEN OF A FEMALE.
+(_Oniscus asellus._)]
+
+In the male, the first two pairs of abdominal appendages are specially
+modified, the inner divisions (endopodites) being long and pointed
+(figs. 15 and 16). The last pair, or tail appendages, in the male are
+often considerably larger than in the female, and the form of these
+structures is sometimes of value in classification.
+
+[Illustration: FIG. 14.--A TYPICAL ABDOMINAL APPENDAGE. (_Oniscus
+asellus._)]
+
+[Illustration: FIG. 15.--THE FIRST ABDOMINAL APPENDAGE OF THE MALE.
+(_Oniscus asellus._)]
+
+[Illustration: FIG. 16.--THE SECOND ABDOMINAL APPENDAGE OF THE MALE.
+(_Oniscus asellus._)]
+
+=Alimentary canal.=--The main portion of the alimentary system is,
+practically speaking, a straight tube (fig. 17). Its first part (not
+shown in the figure) is a narrow gullet, which after passing through
+the nerve collar dilates to form a sort of stomach. Into this the
+secretion of four digestive glands is poured by two ducts. These glands
+have a somewhat striking appearance, being yellow tubes spirally
+coiled, and they end blindly. From the stomach the intestine runs to
+the hinder end of the body and passes under the heart.
+
+=Circulatory system.=--The blood being aërated in the abdominal
+appendages, we find that the heart is situated towards the hinder end
+of the body (fig. 18). Three main arteries supply the thorax and head,
+while the blood is brought from the gills to the heart.
+
+=Excretory system.=--The excretory organs consist of a (_a_) pair of
+so-called "shell glands," which are considered to be the equivalents
+of the excretory tubes or nephridia of annelid worms. In the woodlouse
+these excretory organs open on the second pair of maxillae. They are
+composed of a tube (_sacculus_) closed at one end and more or less bent
+upon itself (5, p. 261) which communicates with a _labyrinth_ that
+is provided with an excretory orifice. Matters are eliminated by the
+_epithelial cells_ [the histology has been described and figured in
+_Ligidium hypnorum_ (66)], which are very large in _Ligia oceanica_.
+
+[Illustration: Fig. 17.--THE ALIMENTARY CANAL. (_Oniscus asellus._)]
+
+[Illustration: Fig. 18.--THE CIRCULATORY SYSTEM. (_Oniscus asellus._)]
+
+(_b_) Masses of cellules in the head, very greatly developed in _Ligia
+oceanica_ (but numbering scarcely more than ten in _Oniscus asellus_),
+which have no external opening. They also function as excretory organs
+(5, p. 263), and have been called "cephalic nephrocytes."
+
+[Illustration: FIG. 19.--THE NERVOUS SYSTEM. (_Oniscus asellus._)]
+
+(_c_) Other "branchial nephrocytes" are situated on the dorsal surface
+between the last thoracic and the first abdominal segments, as well as
+between those that follow, with the exception of the last two; they are
+in distinct patches, one on each of the middle line in _Ligia_, but
+more or less continuous in _Oniscus_ (5, p. 265).
+
+(_d_) The digestive glands have also been shown to be excretory (5, p.
+270).
+
+=Nervous system.=--The nervous system consists of _paired ganglia_
+in the head, above the alimentary canal which send off nerves
+(_commissures_) that meet below, to form a _double nerve cord_ with
+ganglia at intervals (see fig. 19).
+
+[Illustration: FIG. 20.--FEMALE REPRODUCTORY ORGANS. (_Oniscus
+asellus._)]
+
+=Reproductive organs.=--In the female there are a pair of _ovaries_ in
+the positions shewn in fig. 20; and _ducts_ run to the underside of the
+fifth thoracic segment.
+
+The openings are very difficult to identify, and Lereboullet (39, p.
+113) was unable to find them. It is obvious that the openings must be
+underneath the plates that form the egg pouch, and as a change of skin
+is required to set these free, it would appear that at ordinary seasons
+the ducts from the ovaries are closed. The writers have been able to
+determine from external examination of specimens which had moulted and
+were about to lay eggs, that the oviducts at such time open to the
+inside of the base of each walking leg on the fifth segment. In similar
+specimens the oviducts were also followed to the opening from within.
+The _brood pouch_ has already been described.
+
+The male organs consist of six _testes_ arranged in two pairs, each
+of which is provided with a _reservoir_ (see fig. 21). The efferent
+ducts from the two reservoirs unite at the base of the thorax to form a
+common duct (or "penis").
+
+[Illustration: FIG. 21.--THE MALE REPRODUCTORY ORGANS. (_Oniscus
+asellus._)]
+
+=Development.=--The eggs, in the common species of woodlice, at
+least, are laid at the beginning of summer, and are retained in the
+brood pouch, where they undergo their development. The process has
+been recently traced with great care by Professor Louis Roule (58) in
+_Porcellio scaber_ and the description which follows is based upon his
+researches.
+
+As, practically speaking, the larval stages are passed within the egg,
+and there is no free embryo differing in form from the parent, it is
+necessary for the young creatures to be well supplied with nutritive
+material. In fact, the bulk of the large egg is made up of _food-yolk_,
+on the outside of which the _formative protoplasm_ is disposed in
+irregular patches. In the fertilized ovum, one of the latter, which
+lies in a particular position at the end, is found to be larger than
+the others (see fig. 22). It contains the nucleus of the egg-cell (see
+fig. 23) and is called the _cicatricula_. This is the only portion of
+the egg which divides and produces _nucleated cells_. It is these which
+gradually spread all over the surface of the food-yolk, forming a layer
+known as the _blastoderm_, which is at first but one cell thick (see
+figs. 24, 26, and 28).
+
+Before, however, the food-yolk is quite closed in, a differentiation
+into two layers--the _pro-ectoderm_ and _pro-endoderm_--takes place
+(see fig. 25) and rudiments of the first two pairs of _appendages_
+appear (see fig. 26). Moreover, the cells of the ectoderm change their
+shape and begin to multiply at two points to form the beginnings of the
+cerebral ganglia and the nerve cord respectively.
+
+[Illustration: FIG. 22.--THE FERTILIZED EGG (_Porcellio scaber_), AFTER
+ROULE.]
+
+[Illustration: FIG. 23.--THE FERTILIZED EGG SEEN IN SECTION (_Porcellio
+scaber_), AFTER ROULE.]
+
+As the blastoderm closes over the food-yolk, two more appendages arise
+and these are soon followed by others (see fig. 28). A depression
+appears at the point where the blastoderm closed and internally the
+pro-endoderm or inner layer is differentiated into two--the _endoderm
+proper_ and the _mesoderm_ (see fig. 29). The former begins to grow
+so that its edges unite to form the middle part of the intestine (see
+fig. 29) seen from the outside in fig. 30. The depression already
+mentioned grows deeper, forming a tube which is the hind portion of the
+_intestine_, while at the anterior end of the embryo the front part of
+the intestine is similarly formed (see fig. 30). By this time also all
+the nineteen appendages have made their appearance and the mesoderm,
+(which has grown considerably, to form the beginnings of the muscles)
+has sent prolongations into each of them. About this time, spaces (see
+fig. 31) are formed in the muscular mesoderm which are all that remain
+of the _true body cavity_ characteristic of animals above the level of
+the jelly fish, and in these spaces the blood ultimately circulates.
+
+_SURFACE VIEWS._
+
+[Illustration: FIG. 24.]
+
+[Illustration: FIG. 26.]
+
+[Illustration: FIG. 28.]
+
+[Illustration: FIG. 30.]
+
+_OPTICAL SECTIONS._
+
+[Illustration: FIG. 25.]
+
+[Illustration: FIG. 27.]
+
+[Illustration: FIG. 29.]
+
+[Illustration: FIG. 31.]
+
+THE DEVELOPMENT OF A WOODLOUSE (_Porcellio scaber_), AFTER ROULE.
+
+Figs. 24, 26, 28, 30, are Surface Views, and figs. 25, 27, 29, 31,
+which indicate slightly later stages respectively than the others, are
+of egg seen in Optical Section.
+
+The body next alters somewhat in shape and the three divisions of
+the intestine approach one another (see fig. 32) previous to their
+junction. As may be imagined during these processes the food-yolk has
+gradually been used up and the space which it occupied taken by the
+internal organs, which we have mentioned.
+
+[Illustration: FIG. 32.--EMBRYO OF THE WOODLOUSE SHOWING THE THREE
+DIVISIONS OF THE INTESTINE SEPARATELY DEVELOPED (_Porcellio scaber_),
+AFTER ROULE.]
+
+[Illustration: FIG. 33.--EMBRYO OF THE WOODLOUSE SHOWING TRACES OF THE
+SEGMENTS (_Porcellio scaber_), AFTER ROULE.]
+
+[Illustration: FIG. 34.--AN EMBRYO WOODLOUSE READY TO BE HATCHED
+(_Porcellio scaber_), AFTER ROULE.]
+
+In the last stages of the development the appendages become larger
+still, the _heart_ makes its appearance, segmentation of the body is
+completed, and except that the seventh pair of walking legs are as yet
+rudimentary the woodlouse is completed. It is only after hatching that
+the pair of legs mentioned, attain to their normal length.
+
+The process of segmentation of the egg and the formation of its layers
+lasts about a fortnight, while the completion of the development
+proceeds much more rapidly, for another three weeks bring it to an end.
+
+After the first moult or change of skin the last pair of walking
+legs makes its appearance, and Mr. James B. Casserley [whose work
+one of us (75) has described elsewhere] found when keeping a number
+of the common pill-woodlouse (_Armadillidium vulgare_) in captivity
+that his specimens did not subsequently change their skins more than
+once in the six months during which he had them under observation. He
+also noted that the crustaceans go on growing after they are sexually
+mature. As his specimens grew older, Mr. Casserley noticed that their
+colour became darker, and a curious point recorded by him is that two
+examples of the same age may change their skins at the same time,
+and while one may have afterwards nearly twice as many markings, on
+the other very few at all will be seen. The time required for the
+growth of a woodlouse from the size of a pin's head to that of an
+adult example--say three-quarters-of-an-inch long--must be fairly
+considerable, taking into account the fact that any appreciable
+increase in size can only occur at a moult and Mr. Casserley's
+observations as to the infrequency of the process in _Armadillidium
+vulgare_. (See p. 14.)
+
+=Habits and Economic Considerations.=--The construction of the
+breathing organs of woodlice, and the necessity which exists for these
+to be kept moist, restricts the habitats of the animals considerably.
+Woodlice are found under stones and logs, beneath the bark of dead and
+rotten trees, among decaying vegetable matter as well as living grass
+and moss in damp or wet situations. When looking for some of the common
+species under the bark of fallen trees it is surprising to notice that
+the crustaceans may be entirely absent from many trunks, while when
+another is examined which seems to differ very slightly, if at all, in
+condition or situation, they are found in swarms. There is no doubt
+but that the habits of woodlice would well repay the attention of
+naturalists, who are now recognizing that besides anatomy as such, and
+the classification which a knowledge of structure permits, there is the
+equally important consideration of the creatures as they live their own
+life and affect that of others. It is not our object to give a detailed
+account of the ecology of British woodlice, but rather to provide a
+basis from which it may be approached. Nevertheless a few general
+remarks may not come amiss. Many points in the life-history of woodlice
+may no doubt be learned by keeping them in captivity and there is just
+sufficient difficulty in doing this successfully to give an interest to
+the matter.
+
+Apart from a supply of proper food, we take it that the chief object to
+be attained is the provision of the amount of moisture required by the
+particular species under examination, together with a sufficient supply
+of air.
+
+A great many interesting observations can be thus carried out, such
+as those of Mr. Casserley, to which allusion has already been made.
+The process of moulting for instance is well worth watching, and
+although specimens with half their coat changed may be found in remote
+corners, yet the whole course of the moult can be seen much better
+in the case of captive woodlice. The following account is taken from
+Mr. Casserley's description (75) of what happens in the case of
+_Armadillidium vulgare_:--The approach of the moult is indicated by
+the appearance of a white border on each segment of the body, which
+becomes gradually more marked, while at the same time the animal is
+seen to be less active and often makes a small burrow in which to
+hide. Sometimes a sheltered corner against a stone is looked upon as
+affording sufficient protection, but in either case each woodlouse
+keeps to the place originally chosen. About ten days after the white
+lines have become visible the animal appears to be divided into two.
+Its skin is becoming loose and little movement can take place at the
+joints of its body with the exception of that between the fourth and
+fifth thoracic segments where the skin will ultimately break. The
+woodlouse spends a day or two in this condition and then, by suddenly
+walking forward, frees itself from the covering of the hinder portion
+of its body. The three last pairs of walking legs are carefully pulled
+out from the old skin, which now appears perfectly white, and at the
+same time the lining of the hind portion of the alimentary canal (hind
+gut) is also shed. After putting the tender half of his body well into
+his corner or burrow the woodlouse proceeds to eat the part of his skin
+that he has cast. The creature has now a very odd appearance. His front
+half with the exception of the white edges is as it was before, the
+rest of him instead of a light slaty blue, and is very soft as well as
+proportionately a little larger.
+
+In three days or so the tail end becomes hard and attains the normal
+colour. Then the old skin from the front half is pushed off and the
+creature becomes practically defenceless, so much so in fact, that any
+of his species that happen to find him will attack him and eat all his
+front half, rejecting, however, his now hardened tail-end.
+
+Provided that the moulting woodlouse has survived (and in captivity, to
+ensure this, he must be isolated), after three days his jaws will be
+sufficiently hardened to allow of his eating, and usually he first of
+all devours the second half of his cast skin. The operation of moulting
+does not occupy quite so long a time in the case of young examples.
+Specimens half-an-inch long do not moult more than once in six months
+and show but little increase in size after the process.
+
+Woodlice do not appear to live on either animal or vegetable food
+alone, but adopt a mixed diet. It is, however, owing to their attacks
+upon cultivated plants that the creatures are looked upon as pests by
+the horticulturalist. The animals feed either in the night or in the
+very early morning, on seedlings, orchid tubers, mushrooms, or anything
+that comes to hand. Few of the accounts, however, of their ravages,
+mention that the crustaceans have been caught absolutely in the act
+of doing the damage ascribed to them. Some careful inquiries have
+nevertheless enabled us to discover several observers who have watched
+woodlice feeding. Mr. F. V. Theobald, of Wye College, and one of the
+students at Swanley Horticultural College are among the number. The
+former has also given us an account of the methods, out of many tried,
+which he has found most successful for getting rid of the crustaceans.
+Out of doors trapping with moss, sacking or horse-dung is best. In
+glass houses, fumigation with hydro-cyanic acid gas has cleared them
+out, and poison baits, especially potatoes cut and soaked in white
+arsenic, have done some good. Stable manure is especially favourable to
+these creatures, particularly when it is used "long": in this condition
+it should therefore be avoided.
+
+It is interesting to note how the woodlice in winter simply remain
+where they happen to be so long as there is sufficient moisture, though
+they are ready to run about as rapidly, for a time, as in summer,
+should they happen to be disturbed.
+
+No doubt many points of inter-relation between woodlice and other
+animals remain to be discovered. Mr. John W. Odell tells us that on
+Exmoor, in the open, he found no _Armadillidia_, though other forms
+occurred under nine out of every ten stones that he turned over, and
+here the smaller species of ants also abounded. Close to stone walls
+_Armadillidia_ were to be seen to the exclusion of all other genera,
+and this state of affairs was ascribed by Mr. Odell to the presence of
+swarms of the large wood-ants which he considers would make short work
+of any woodlice that could not protect themselves by rolling up.
+
+We ought not to conclude this account without mentioning the fact that
+woodlice once played an important part in medicine.
+
+Doctor Fernie (28) gives some interesting extracts with regard to the
+hog-louse and the woodlouse. The latter he seems to have identified
+quite correctly as _Oniscus asellus_. He calls the former, however,
+indiscriminately, "the common armadillo" (which is the old name for
+the pill-woodlice now known as _Armadillidium_), "the pill millipede"
+and "_Glomeris marginata_." The last two names are those of another
+creature, not a crustacean, which when it is rolled up can be very
+easily mistaken for an _Armadillidium_, though, when it uncurls, it
+will be seen to have many more than seven pairs of legs. The local
+appellations applied to the hog-louse by Doctor Fernie, and his remarks
+with regard to its commonness, tend to show that it is _Armadillidium
+vulgare_, to which he really refers, and the use of which in medicine
+was commonly general.
+
+Hog-lice were prescribed for scrofulous diseases and obstructions of
+the liver and digestive organs, among other things, and the London
+College of Physicians directed that the creatures should be prepared
+by suspending them in a thin canvas bag placed within a covered vessel
+over the steam of hot spirit or wine, so that being killed by the
+spirit they might become friable. Hog-lice and Woodlice were also
+administered alive, while the former were also put down the throats of
+cows "to promote the restoration" of their cud, hence their name of
+"cud-worm." There seems to be considerable evidence that even in modern
+times Woodlice have had considerable remedial effect which depends upon
+"an alkalescent fluid" contained in them.
+
+=Local Names.=--Among the local names by which these creatures are
+known are those of "sow bug," "lucre pig" (Berkshire), "carpenter"
+and "chiselhog" (Berkshire). Doctor Fernie (28) gives a number of
+others:--"thrush-louse," "tiggyhog," "cheslip," "kitchenball,"
+"chiselbob," "lugdor," "palmer," and "cudworm." In the eastern
+counties the same writer notes that they are known as "old-sows" or
+"St. Anthony's hogs" while the Welsh call them "little grey-hogs," "the
+little old women of the wood" or "grammar-sows," grammar signifying
+a shrivelled up old dame. _Oniscus asellus_ was sometimes called
+"socchetre," "church louse," and "chinch."
+
+=Methods of Collection and Preservation.=--Woodlice should be collected
+straightway into tubes or bottles half filled with 30 per cent.
+methylated spirit.[3] Woodlice dropped into this weak spirit become
+gradually narcotised and die, and they remain limp enough for purposes
+of examination or to allow, of their legs and antennæ being set out
+during the process of mounting. Specimens to be kept permanently should
+be placed in 70 per cent. alcohol. For storage purposes the specimens
+of each species from a given locality should be put together into a
+small flat bottomed tube such as is used for pillules by apothecaries
+or specially made for natural history purposes. A paper label on
+which the name, locality, date of capture and any other necessary
+particulars have been written with dark lead pencil, is not affected by
+the spirit. The tubes may be corked, though if not frequently examined
+all the spirit may evaporate, and cause the specimens to be spoilt. A
+safer method is to plug the tubes with cotton wool and keep all those
+containing a given species or specimens from a particular locality
+beneath the surface of spirit in a large wide-mouthed bottle, into
+which first of all some cotton wool has been put to prevent the tubes
+from coming into sudden contact with the glass at the bottom. For show
+purposes in museums, specimens taken direct from 30 per cent. spirit
+should be mounted on slips of opal glass by means of gum-tragacanth
+which has been powdered and shaken up in spirit before having water
+added to it. The slips can be exhibited in glass tubes, six inches high
+by one across, or in narrow stoppered museum jars. A variation of the
+method is to mount the animals on clear glass and to place behind them
+another strip of any colour that may be preferred.
+
+=Classification.=--The various genera of woodlice are connected
+together so closely, by intermediate forms, that their division into
+families is, to a very great extent, arbitrary. Bate and Westwood
+described but a single family Oniscidæ (I), though they distinguished
+two sub-families:--Ligiinæ, which included the forms with many joints
+to the flagellum of the antenna, and Oniscinæ, which contained the rest.
+
+Since then the pill-woodlice have been thought by some to be
+sufficiently different from the other genera to warrant their
+separation, and three families namely, Ligiidæ, Oniscidæ, and
+Armadillidæ have been recognized, as for instance by Dr. Scharff (63).
+
+A fourth family--Trichoniscidæ--has been added by Professor G. O. Sars,
+who in his _Crustacea of Norway_ (59) alludes to the division of the
+tribe into the sections Ligiæ and Onisci and has adopted the following
+classification:--
+
+_Order_--=ISOPODA.=
+
+_Tribe_--ONISCOIDA.
+
+  _Family I._--LIGIIDAE.
+             _Ligia._
+             _Ligidium._
+
+  _Family II._--TRICHONISCIDÆ.
+              _Trichoniscus._
+              _Trichoniscoides._
+              _Haplophthalmus._
+
+  _Family III._--ONISCIDÆ.
+               _Oniscus._
+               _Philoscia._
+               _Platyarthrus._
+               _Porcellio._
+               _Metoponorthus._
+               _Cylisticus._
+
+  _Family IV._--ARMADILLIDIIÆ.
+              _Armadillidium._
+
+All the genera described by Professor Sars are represented in the
+British Islands.
+
+       *       *       *       *       *
+
+Below is a scheme of classification and synopsis of the characters of
+British genera of woodlice which we have compiled in order to render
+easy the determination of the genus to which any particular specimen
+may belong.
+
+_SCHEME OF CLASSIFICATION AND SYNOPSIS OF GENERIC CHARACTERS._
+
+_Order_--=ISOPODA.=
+
+_Tribe_--ONISCOIDA.
+
+
+_Section I._--=LIGIÆ.=
+
+  _The Two Divisions of the Tail Appendages alike in Shape._
+
+  (A.)--Flagellum with 10 or more joints; tail
+         appendages wholly visible; head without
+         lateral lobes                               LIGIIDAE.
+            (1.)--Abdomen broad; body large;
+                   habitat, the sea-shore            _Ligia._
+            (2.)--Abdomen narrow; habitat, wet
+                   moss                              _Ligidium._
+
+  (B.)--Flagellum with less than 10 joints; head
+         with small lateral lobes, tail appendages
+         partly covered                              TRICHONISCIDÆ.
+            (3.)--Abdomen narrow; eyes compound;
+                   flagellum usually with more
+                   than 3 joints                     _Trichoniscus._
+            (4.)--Abdomen narrow; eyes simple or
+                   wanting; flagellum with 4 joints  _Trichoniscoides._
+            (5.)--Abdomen broad (comparatively);
+                   eyes simple; back with
+                   longitudinal ridges; flagellum
+                   with 3 joints                     _Haplophthalmus._
+
+
+_Section II._--=ONISCI.=
+
+  _The Outer Divisions of the Tail Appendages Broader than the Inner._
+
+  (A.)--Tail appendages projecting when the animal
+         is walking                                  ONISCIDÆ.
+      (a.)--Unable to roll up into a complete ball.
+            (6.)--Flagellum with 3 joints; abdomen
+                   broad; head, with lateral lobes   _Oniscus._
+            (7.)--Flagellum with 3 joints; abdomen
+                   narrow; head without lateral
+                   lobes                             _Philoscia._
+            (8.)--Flagellum with 1 joint; eyes
+                   wanting; abdomen broad; habitat,
+                   ant's nests                       _Platyarthrus._
+            (9.)--Flagellum with 2 joints; abdomen
+                   broad; frontal lobe projecting    _Porcellio_.
+           (10.)--Flagellum with 2 joints; abdomen
+                   narrow                            _Metoponorthus._
+      (b.)--Able to roll up into a complete ball.
+           (11.)--Flagellum with 2 joints; antennae
+                   folded together over the thorax
+                   when the animal is rolled up
+                   into a ball                       _Cylisticus._
+
+  (B.)--Tail appendages not projecting when the
+         animal walking                              ARMADILLIDIIDÆ.
+           (12.)--Flagellum with 2 joints; antennae
+                   hidden or carried at the sides
+                   of the head when the animal is
+                   rolled up into a ball             _Armadillidium._
+
+=British Species.=--Naturalists in this country paid little attention
+to the recognition or description of Woodlice, until the latter half of
+the nineteenth century.
+
+In 1857 Kinahan read a paper before the British Association (32) in
+which he described fourteen species of woodlice from the British
+Islands, and eleven years later when Bate and Westwood published
+their book (1), the number had risen to seventeen. One of the species
+(_Oniscus fossor_), however, was doubtful, and although Dr. Scharff
+in 1894 (63) rejected it, his list contained also seventeen species,
+for in the meantime the Rev. T. R. R. Stebbing had found _Ligidium
+hypnorum_ in Surrey (70).
+
+Since then the Rev. Canon Norman, Dr. Scharff, the Rev. T. R. R.
+Stebbing, and one of the present writers, have added other species, as
+will be seen from the following pages, in which all those found, up to
+the present time in the British Islands are described and figured.
+
+We shall now consider in detail the British genera and species of
+woodlice and give their synonymy and distribution.
+
+_Order_--=ISOPODA.=
+
+_Tribe--ONISCOIDA._
+
+
+_Section_--=LIGIÆ.=
+
+THE TWO DIVISIONS OF THE TAIL APPENDAGES ALIKE IN SHAPE.
+
+_Family_--LIGIIDÆ.
+
+=Flagellum with ten or more joints; tail appendages wholly visible;
+head without lateral lobes.=
+
+_Genus_--=LIGIA= Fabricius, 1798 (27), p. 301.
+
+_Abdomen broad; body large; habitat, the sea-shore._
+
+The genus _Ligia_ agrees with _Ligidium_ alone, in that the flagellum
+of the larger antennæ has more than ten joints. In both genera, there
+are no lateral lobes to the head, and the tail appendages are wholly
+visible from the upper surface of the body. The latter in _Ligia_ is,
+however, very many times bigger than in _Ligidium_ and shows no abrupt
+decrease in the width of its segments when the abdomen is reached.
+
+=Ligia oceanica= Linné (The Quay-louse). PLATE I.
+
+  1767  _Oniscus oceanicus_ Linné (43), p. 1061.
+  1793  _Cymothoa oceanica_ Fabricius (26), p. 509.
+  1815  _Ligia scopulorum_ Leach (38), p. 374.
+  1868  _Ligia oceanica_ Bate and Westwood (1), p. 444.
+  1898  _Ligia oceanica_ Sars (59), 156, pl. LXX.
+
+There is but one British species of _Ligia_, and this, the largest
+member of the whole tribe to be met with in these Islands, usually
+attains a length of two centimetres, while adult males may be nearly
+half as long again. It is the _Oniscus oceanicus_ of Linnæus and lives
+on the sea shore, where it may be found at low tide beneath stones and
+rubbish in the crevices of timber. _Ligia_ forms a connecting link
+between the woodlice proper and the many Isopods which actually live in
+the sea.
+
+The colour of the animals is a greenish grey, and the compound eyes
+are almost black, so that they are very conspicuous; there are from
+eleven to fourteen joints to the flagellum of the outer antennae and
+this feature, taken in conjunction with the large size and habitat, is
+sufficient to identify the species in question.
+
+On the coast of Essex the name "quay-lowders" is given to these
+crustaceans, "lowder" being apparently an old plural of louse.
+
+[Illustration: FIG. 35.--FLAGELLUM AND LAST PEDUNCULAR JOINT OF THE
+ANTENNA OF _Ligia oceanica_.]
+
+It is worthy of mention that Mr. Webb, when in charge of the Marine
+Biological Station at Brightlingsea, examined a very large male
+specimen of _Ligia oceanica_, in which the maxillæ were duplicated and
+consisted of four pairs instead of two.
+
+_BRITISH LOCALITIES:--_
+
+  _England_: Brightlingsea; (W.M.W.): Maldon; (W.M.W. from R.M.):
+     Southend; (J.A.M.): Whitstable; (W.M.W.): Herne Bay; Margate;
+     Dover; Folkestone; (J.A.M.)
+
+  _Scotland_: Shetland to Cornwall; (Norman, 49).
+
+  _Ireland_: East Coast; West Glengariff; Castletown; Berehaven;
+     Bundoran; (Scharff, 63).
+
+_FOREIGN DISTRIBUTION:--_
+
+  _Europe_: France; (25): Spain; (12): Denmark; Prussia; Norway;
+     Faroe Islands; Belgium; (59).
+
+  _Africa_: Morocco; (16).
+
+_Genus_--=LIGIDIUM= Brandt, 1833 (3), p. 173. Zia, Koch (34).
+
+_Abdomen narrow; habitat, wet moss._
+
+In _Ligidium_ there are numerous joints to the flagellum, lateral
+lobes are absent from the head, and the tail appendages are completely
+to be seen. All the segments of the abdomen are distinctly narrower
+than those of the thorax and in this it agrees with _Trichoniscus_,
+_Trichoniscoides_, _Philoscia_, and _Metoponorthus_. In these, however,
+the flagellum has never more than seven joints, the tail appendages (as
+in all genera but _Ligia_ and _Ligidium_) are partially hidden by the
+last segment, and in all the four but _Philoscia_ there are lobes to
+the head.
+
+=Ligidium hypnorum=, Cuvier. PLATE II.
+
+  1792 _Oniscus hypnorum_ Cuvier (9), pl. XXVI., figs. 3-5.
+  1793 _Oniscus agilis_ Persoon, quoted by Koch in Panzer (51),
+        part 5, pl. XXIV.
+  1830 _Ligia hypnorum_ Bosc (2), p. 179.
+  1833 _Ligidium persoonii_ J. F. Brandt (3), p. 174, pl. IV.,
+        figs. 6-7.
+  1840 _Zia agilis_ Koch (34), part 34, pls. XXII. and XXIII.
+  1844 _Ligidium personii_ Zaddach (77), p. 17.
+  1853 _Ligidium personii_ Lereboullet (39), p. 14, pl. I., fig. 1,
+        pl. II., figs. 20-31.
+  1857 _Ligidium personii_ Kinahan (32), p. 275, pl. XXI., fig. 14,
+        pl. XXII., fig. 9.
+  1873 _Zia saundersii_ Stebbing (70), p. 286.
+  1873 _Ligidium agile_ Norman (48), p. 419.
+  1885 _Ligidium hypnorum_ Budde-Lund (8), p. 254.
+  1898 _Ligidium hypnorum_ G. O. Sars (59), p. 158, pl. LXXI.
+
+This species, which like the last, is the only British representative
+of its genus, was added to our fauna in 1873 by the Rev. Thomas R. R.
+Stebbing (70) who found specimens in the neighbourhood of Copthorne
+Common, Surrey. Up to the present time, when we are pleased to announce
+that we discovered it in the spring of 1902 at Warley in Essex,
+_Ligidium hypnorum_ has not been recorded from any other place in the
+British Islands.
+
+[Illustration: FIG. 36.--FLAGELLUM AND LAST PEDUNCULAR JOINT OF THE
+ANTENNA OF _Ligidium hypnorum_.]
+
+As the name of the species implies, it lives in wet situations and in
+its turn connects _Ligia_ with the forms which inhabit drier places.
+_Ligidium hypnorum_ might be mistaken for _Philoscia muscorum_, but as
+already pointed out in the generic description, the latter has but a
+few (three) joints to the flagellum, instead of from ten to thirteen.
+From _Ligia_, the species under consideration is distinguished by its
+small size, narrow abdomen, and habitat.
+
+_BRITISH LOCALITIES:--_
+
+  _England_: Warley, Essex; (W.M.W.): Copthorne Common, Surrey;
+     (Stebbing, 70).
+
+_FOREIGN DISTRIBUTION:--_
+
+  _Europe_: France; (25): Sweden; Denmark; Germany; (59): Turkey; (8).
+
+_Family_--TRICHONISCIDÆ.
+
+=Flagellum with less than ten joints; head with lateral lobes; tail
+appendages partly hidden.=
+
+_Genus_--=TRICHONISCUS= Brandt, 1833 (3), p. 174.
+
+_Abdomen narrow; eyes compound; flagellum, usually with more than three
+joints._
+
+In _Trichoniscus_ the flagellum may have from seven to four (rarely
+three) joints. As in _Trichoniscoides_ and _Haplophthalmus_ there are
+lateral lobes to the head, though these are not very pronounced; the
+body is also of small size, the abdomen narrow with both divisions of
+the tail appendages equally so, and almost of the same length though
+slightly covered by the last segment. The compound eyes distinguish
+_Trichoniscus_ from the two genera named, and from _Platyarthrus_,
+while its small size and the character of its tail-parts mark it out
+from all others.
+
+=Trichoniscus pusillus= Brandt. Plate III.
+
+  1833 _Trichoniscus pusillus_ Brandt (3), p. 174, pl. IV., fig. 9.
+  1838 _Itea riparia_ Koch (34), part 22, pl. XVII.
+  1844 _Itea lævis_ Zaddach (77), p. 16.
+  1857 _Philougria celer_ Kinahan (32), p. 281, pl. XXII., figs. 1-4.
+  1858 _Philougria riparia_ Kinahan (33), pp. 191 and 198, pl. XXIII.,
+        fig. 1.
+  1868 _Philougria riparia_ Bate and Westwood (1), p. 456.
+  1898 _Trichoniscus pusillus_ Sars (59), p. 161, pl. LXXII., fig. 1.
+
+This tiny species is found commonly amongst the roots of the herbage in
+very moist places. It presents a horny translucent appearance and is
+of a reddish brown colour. It runs with considerable speed, and when
+it is moving, the white irregular lines with which it is beset are
+not evident. _Trichoniscus pusillus_ is very much like _Trichoniscus
+vividus_ in colour but the latter species is nearly twice as big and
+has from five to seven joints to the flagellum, while the former has
+never more than four. _Trichoniscus roseus_ is also much larger and
+its bright red colour (which it loses, however, when preserved in
+alcohol) is another means of distinguishing it from the species under
+consideration.
+
+Professor Sars in his _Crustacea of Norway_ (p. 162) describes from
+Christiania, under the name of _Trichoniscus pygmæus_, a still smaller
+species. As this may possibly be discovered in this country a brief
+comparison between it and _Trichoniscus pusillus_ may be of value.
+The former reaches a length of but two millimetres; it is "whitish,
+semi-pellucid with a few light brown pigmentary ramifications across
+the segments and a double row of irregular opaque patches along the
+middle of its back" (p. 163). Its body is covered with minute tubercles
+and there are only three joints to the flagellum; its movements are by
+no means rapid.
+
+[Illustration: FIG. 37.--FLAGELLUM AND LAST PEDUNCULAR JOINT OF THE
+ANTENNA OF _Trichoniscus pusillus_.]
+
+The body of _Trichoniscus pusillus_ is smooth and polished. It has four
+joints to the flagellum--Dr. Scharff (63) says three or four--and it
+moves quickly.
+
+_BRITISH LOCALITIES:--_
+
+  _England_: Brightlingsea; Warley; (W.M.W.): Epping Forest; (Bate
+     and Westwood, 1): Hanwell; Southall; Kew Gardens; Langley; Burnham
+     Beeches; Dropmore; Skirmett; Bluebell Hill, Maidstone; (W.M.W.):
+     Chislehurst; Plymouth; Polperro; Looe; (Bate and Westwood, 1):
+     Hertfordshire; Northumberland; Durham; (Norman, 49): Exeter;
+     (Parfitt, 53).
+
+  _Scotland_: Edinburgh; (Scott, 68): Cumbrae; (Robertson, 57).
+
+  _Ireland_: Connemara; (Norman, 49): Dublin; Wexford; Cork and
+     Kerry; (Percival Wright _teste_ Bate and Westwood, 1): Tyrone;
+     Waterford; Portlaw; Kilkenny; Wicklow; (Kinahan, 33).
+
+_FOREIGN DISTRIBUTION:--_
+
+  _Europe_: France; (25): Spain; (15): Italy; (19): Norway; Sweden;
+     Denmark; Germany; (59).
+
+  _Africa_: Algeria; Tunis; Azores; (24).
+
+  _America_: Niagara; North America; (59).
+
+=Trichoniscus vividus=, Koch. PLATE IV. (from a spirit specimen).
+
+  1840  _Itea vivida_ Koch (34), part 34, pl. IV.
+  1858  _Philougria vivida_ Kinahan (33), pp. 197 and 198, pl. XXIII.,
+         fig. 2.
+  1868  _Philougria vivida_ Bate and Westwood (1), Vol. II., pp. 458
+         and 459, figs.
+
+This species is claret-brown in colour and under a lens it is seen
+to be marbled with white, indeed in appearance it is much like
+_Trichoniscus pusillus_ though twice the size. There are important
+differences between the two species as regards the number of joints to
+the flagellum. These vary from five to seven in _Trichoniscus vividus_
+while in the other, as already pointed out, there are not more than
+four. The body is practically speaking smooth for it bears only very
+small tubercles, widely separated. In _Trichoniscus vividus_ the
+antennæ lack the bristles which characterise those of the other species
+in the genus. The species under consideration was discovered by Dr.
+Kinahan in March, 1858, at Portlaw, Co. Waterford and is active even
+amongst the snow.
+
+[Illustration: FIG. 38.--FLAGELLUM AND LAST PEDUNCULAR JOINT OF THE
+ANTENNA OF _Trichoniscus vividus_.]
+
+_BRITISH LOCALITIES:--_
+
+  _Ireland_: Portlaw, Co. Waterford; (Kinahan, 33): Cappagh, Co.
+     Waterford; (Scharff, Irish Nat., Vol. IX., p. 158): Borris, Co.
+     Carlow; (Scharff, 64.)
+
+_FOREIGN DISTRIBUTION:--_
+
+  _Europe_: Spain; (12).
+
+=Trichoniscus roseus= Koch. PLATE V.
+
+  1838  _Itea rosea_ Koch (34), part 122, pl. XVI.
+  1858  _Philougria rosea_ Kinahan (33), pp. 197 and 199, pl. XXIII.,
+         fig. 3.
+  1858  _Philougria rosea_ Bate and Westwood (1), p. 460.
+  1898  _Trichoniscus roseus_ Sars (59), p. 163, pl. LXXIII., fig. 1.
+
+The third British species of _Trichoniscus_ is of a deep pink colour
+and has a light yellow stripe down the back (in some habitats the
+animals are said to be quite white). Arranged in transverse rows upon
+the body are large tubercles, each of which under strong magnification
+will be found to end in a tiny hair. It is distinguished from
+_Trichoniscus pusillus_ by the larger size of its body, which is
+also comparatively broader, and from _Trichoniscus vividus_ by the
+four joints of the flagellum of its antennæ which latter have strong
+bristles upon them. In the former species there are five or more joints
+to the flagellum and the antennæ, though hairy, lack the bristles.
+_Trichoniscus roseus_ is to be looked for in old gardens.
+
+[Illustration: FIG. 39.--FLAGELLUM AND LAST PEDUNCULAR JOINT OF THE
+ANTENNA OF _Trichoniscus roseus_.]
+
+_BRITISH LOCALITIES:--_
+
+  _England_: Warley; (W.M.W.): Maldon; (W.M.W. from R.M.): Stanmore;
+     Hanwell; Ealing; Wimbledon; (W.M.W.): Berkhamsted; Torquay;
+     (Norman, 49): Plymouth; (Bate and Westwood, 1 and B.M.,):
+     Grassendale, near Liverpool; (R.W.): Newtownards; (R.W., Irish
+     Nat, 1904, p. 260.)
+
+  _Scotland_: Tarbert; (Scot, 68).
+
+  _Ireland_: Dublin; Ballyfinder, Co. Down; (Scharff, 63):
+     Templeogue; Dundrum; Blackrock; Rathgar, Co. Dublin; Bray, Co.
+     Wicklow; (R.F.S.): Oakleigh; Kerry; (R.W.): Belfast; (Welch, Irish
+     Nat., 1896, p. 213.): At the grave of Josiah Welch (grandson of
+     John Knox), Castle Upton; Richhill, Co. Armagh; Castleconnell
+     Ferry; (R.W.): Glenade House, Co. Antrim; (R.W. from R. Ll.
+     Praeger).
+
+_FOREIGN DISTRIBUTION:--_
+
+  _Europe_: France; (25): Spain; (12): Italy; (59): Denmark;
+     Germany; Holland; (39): Dalmatia; (18).
+
+  _Africa_: Algeria; Tunis; (24).
+
+_Genus_--=TRICHONISCOIDES=, Sars, 1898 (59), p. 164.
+
+_Abdomen narrow; eyes simple; (or wanting); flagellum, with four
+joints._
+
+The members of this genus are very much like those of _Trichoniscus_.
+In the latter, however, the hinder legs are longer in proportion and
+the eyes are compound.
+
+=Trichoniscoides albidus= Budde-Lund. PLATE VI.
+
+  1879  _Trichoniscus albidus_ Budde-Lund (7) p. 9.
+  1898  _Trichoniscoides albidus_ Sars (59), p. 165, pl. LXXIII.,
+         fig. 2.
+
+[Illustration: FIG. 40.--FLAGELLUM AND LAST PEDUNCULAR JOINT OF THE
+ANTENNA OF _Trichoniscoides albidus_.]
+
+We are able to include this species, as a specimen was found by Mr.
+Webb at Eton Wick in the summer of 1899. It is one of a number of
+species which the Rev. Canon Norman (49, p. 18) suggested as likely to
+be British. It is the only representative of its genus, which does not
+differ in any very important characters from the others in the family.
+The narrow elongated body will serve to separate it from _Trichoniscus
+vividus_ and _Trichoniscus roseus_, but on account of its size, which
+is much the same as that of _Trichoniscus pusillus_ and the two British
+species of _Haplophthalmus_, it will be advisable to give some further
+points of distinction. From the first its white colour will serve
+to differentiate it; the other two lack the narrow abdomen seen in
+_Trichoniscoides albidus_. Moreover, not one of the three shows the
+serrations on the side plates which characterise the species under
+consideration. _Platyarthrus hoffmannseggii_ is small and white and
+the edges of its side plates are toothed, but it is oval in shape,
+possesses no eyes, and its stout antennæ have but a single joint to the
+flagellum instead of four. On the Continent this species has been found
+in rich soil.
+
+_BRITISH LOCALITIES:--_
+
+  _England_: Eton; (Stebbing, 71a): Sunderland; (Brady, 50a).
+
+
+_FOREIGN DISTRIBUTION:--_
+
+  _Europe_: France; Wimereux and Lyons, Forêt (25): Norway;
+     Denmark; (59).
+
+_Genus_--=HAPLOPHTHALMUS= Schöbl, 1850 (66), p. 449.
+
+_Abdomen broad (comparatively); eyes simple; flagellum with three
+joints; back with longitudinal ridges._
+
+The body of _Haplophthalmus_ is long in proportion to its width, but
+there is no abrupt decrease in the breadth of the abdomen as seen in
+_Trichoniscus_ and _Trichoniscoides_. The eyes are simple as in the
+latter genus and the lateral lobes of the head are rather large, while
+the side plates of the body are well separated.
+
+=Haplophthalmus mengii= Zaddach. PLATE VII.
+
+  1844  _Itea mengii_ Zaddach (77), p. 16.
+  1860  _Haplophthalmus elegans_ Schöbl (66), p. 449.
+  1885  _Haplophthalmus mengii_ Budde-Lund (8), p. 250.
+  1898  _Haplophthalmus mengii_ Sars (59), p. 167, pl. LXXIV.,
+         fig. 1.
+
+The Rev. Canon Norman discovered two specimens of this species in
+Ireland in June, 1900 (50); in the previous year one of us (Mr. Webb)
+found a single example at Eton Wick.
+
+The main differences between the members of this genus and their allies
+are set forth in the generic description and incidentally elsewhere, so
+we shall content ourselves with giving the distinctive points of the
+two British species. _Haplophthalmus mengii_ has a number of raised
+longitudinal ribs on each segment of the thorax, the outer ridges being
+somewhat broken. There are also two prominent ribs upon the third
+segment of the abdomen.
+
+[Illustration: FIG. 41.--FLAGELLUM AND LAST PEDUNCULAR JOINT OF THE
+ANTENNA OF _Haplophthalmus mengii_.]
+
+_BRITISH LOCALITIES:--_
+
+  _England_: Eton; (Stebbing, 71a): Sunderland; (Brady, 50a).
+
+  _Ireland_: Corcumroe Abbey; Co. Clare (Norman, 50).
+
+_FOREIGN DISTRIBUTION:--_
+
+  _Europe_: France; (25): Norway; Prussia; Germany; Bohemia; (59).
+
+=Haplophthalmus danicus= Budde-Lund. PLATE VIII.
+
+  1870  _Haplophthalmus elegans_ Budde-Lund (6), p. 228
+         (not _Haplophthalmus elegans_ Schöbl).
+  1879  _Haplophthalmus danicus_ Budde-Lund (7), p. 9.
+  1881  _Haplophthalmus mengii_ Weber (76), p. 192, pl. V., figs. 7-9
+         (not _Itea mengii_ Zaddach).
+  1885  _Haplophthalmus danicus_ Budde-Lund (8), p. 250.
+  1898  _Haplophthalmus danicus_ Sars (59), p. 168, pl. LXXIV., fig. 2.
+
+This species was added to the British list by the Rev. Canon Norman
+(49), who found a colony in his garden at Berkhamsted. It has rows of
+tubercles on its thorax instead of ridges, and there are no ribs at all
+upon the abdomen. The front of the head projects further comparatively
+and forms a more acute point than in _Haplophthalmus mengii_ and it is
+not so purely white in colour as the latter species.
+
+[Illustration: FIG. 42.--FLAGELLUM AND LAST PEDUNCULAR JOINT OF THE
+ANTENNA OF _Haplophthalmus danicus_.]
+
+_BRITISH LOCALITIES:--_
+
+  _England_: Warley Place; (W.M.W. from Miss Willmott): Queen's
+     Cottage, Kew Gardens; Stanmore; Hanwell, garden at Odstock,
+     Bennett's Nurseries; (W.M.W.): Berkhamsted; (Norman, 49):
+     Sunderland; (Brady, 50a).
+
+_FOREIGN DISTRIBUTION:--_
+
+  _Europe_: France; (25): Denmark; Holland; Germany; (Dollfus, Feu
+     de Jeun, Nat., April, 1896): Norway; (Sars, 59).
+
+
+_Section_--=ONISCI.=
+
+THE OUTER DIVISIONS OF THE TAIL APPENDAGES BROADER THAN THE INNER ONES.
+
+_Family_-ONISCIDÆ.
+
+=Tail appendages projecting when the animal is walking.=
+
+  (1.) Unable to roll up into a complete ball.
+
+_Genus_-=ONISCUS= Linné 1746 (41), p. 360.
+
+_Flagellum, with three joints; abdomen broad; head with lateral lobes._
+
+The characters given above taken in conjunction with the size of the
+animals will serve to distinguish the members of this genus.
+
+=Oniscus asellus= Linné (The "Common Slater.") PLATE IX.
+
+  1761  _Oniscus asellus_ Linné (41), p. 500, No. 2058.
+  1792  _Oniscus murarius_ Cuvier (9), p. 22, pl. XXVI.
+  1838  _Oniscus fossor_ Koch (34), part 22, pl. XXII.
+  1868  _Oniscus asellus_ Bate and Westwood (1), p. 468.
+  1868  _Oniscus fossor_ Bate and Westwood (1), pp. 471-2.
+  1898  _Oniscus asellus_ Sars (59), p. 171, pl. LXXV.
+
+_Oniscus asellus_ is one of the largest of our woodlice and it is also
+probably the commonest, though _Porcellio scaber_ is in many places
+quite as abundant. The body of _Oniscus_ is broad and expanded and the
+colour is usually a slate grey with yellowish markings more or less
+regularly arranged.
+
+From the genus _Porcellio_ the species with which we are concerned
+is at once distinguished by the three jointed flagellum. _Porcellio_
+has but two joints and has, besides, a prominent lobe projecting from
+the middle of the head, which is not seen in _Oniscus_. _Philoscia_,
+although it has three joints to the flagellum, has a narrow abdomen
+and lacks entirely the lateral lobes which are a feature of the other
+genera of Oniscidæ.
+
+_Oniscus fossor_ of Koch (34) was recognized by Kinahan and by Bate and
+Westwood as a species. Dr. Scharff submitted specimens to Professor
+Budde-Lund who found no differences between them and _Oniscus asellus_.
+The former (63) mentions, however, that the characteristics of the
+supposed species are those of young examples of _Oniscus asellus_, and
+Professor Sars (59, p. 173) seems to be of the same opinion. Many young
+examples of _Oniscus asellus_ that we have examined have a curious
+whitish transverse band owing to the light colour of the dorsal plates
+of the first abdominal segments. The flagellum also does not seem to
+shew in young animals a distinct division into three joints.
+
+[Illustration: FIG. 43.--FLAGELLUM AND LAST PEDUNCULAR JOINT OF THE
+ANTENNA OF _Oniscus asellus_.]
+
+_BRITISH LOCALITIES:--_
+
+  _England_: High Beach, Epping, including an albino; Maldon;
+     Brightlingsea; Iver; Hanwell; Eton; Kew; Pamber Forest;
+     Kingston-on-Soar; Bluebell Hill, Maidstone; (W.M.W.):
+     Lynmouth; (W.M.W. from J.T.C.).
+
+  _Scotland_: (Scharff, 63). Dinnet, Aberdeenshire; (W.M.W. from
+     Madame Christen).
+
+  _Ireland_: (Scharff, 63). Yellow form with black spots, Donegal (R.W.)
+
+_FOREIGN DISTRIBUTION:--_
+
+  _Europe_: Almost throughout; (12): France; (25): Spain; (12):
+     Sweden Norway; Denmark; Germany; Holland; Italy; Iceland; (59):
+     Faroe Islands; Thorsharn; (R.F.S.)
+
+  _Africa_: Azores; (24).
+
+  _America_: Greenland; (59): North America; (Budde-Lund).
+
+_Genus_--=PHILOSCIA= Latreille, 1804 (37), p. 43.
+
+_Flagellum with three joints; abdomen narrow; head without lateral
+lobes._
+
+If any further differences of an obvious kind be required to
+distinguish _Philoscia_ from _Oniscus_, one at least will be found in
+the much greater development of the hinder legs in the former genus.
+
+=Philoscia muscorum= Scopoli. PLATE X.
+
+[Not of Lereboullet, which is an _Oniscus_, see Bate and Westwood (1).]
+
+  1763  _Oniscus muscorum_ Scopoli (67), p. 415.
+  1793  _Oniscus sylvestris_ Fabricius (26), p. 397.
+  1793  _Oniscus agilis_ Koch in Panzer (51), part 9, pl. XXIV.
+  1833  _Philoscia marmorata_ Brandt (3), p. 183.
+  1838  _Ligia melanocephala_ Koch (34), part 22, pl. XVIII.
+  1847  _Zia melanocephala_ Koch (38), part 40, pl. I. p. 212.
+  1868  _Philoscia muscorum_ Bate and Westwood (1), p. 450.
+  1898  _Philoscia muscorum_ Sars (59), p. 174, pl. LXXVI., fig. 1.
+
+This species lives chiefly at the roots of grass and under the stones
+or sticks that lie among it. _Philoscia muscorum_ has a very smooth and
+shining body, and its long legs enable it to move very rapidly. The
+ground colour of its dorsal surface varies from light yellow to deep
+brown. There are characteristic dark markings down the middle of the
+thorax and on the sides, between which are lighter patches. In dark
+coloured specimens the markings are by no means so evident.
+
+[Illustration: FIG. 44.--FLAGELLUM AND LAST PEDUNCULAR JOINT OF THE
+ANTENNA OF _Philoscia muscorum_.]
+
+_BRITISH LOCALITIES:--_
+
+  _England_: High Beach, Epping; Warley; (W.M.W.): Maldon; (W.M.W.
+     from R.M.): Kew; Langley; Hanwell, yellow variation; Bluebell
+     Hill, Maidstone; (W.M.W.): Liphook; (C.S.): Pamber Forest;
+     Kingston-on-Soar; (W.M.W.)
+
+  _Scotland_: (Scott, 68).
+
+  _Ireland_: Almost throughout; (Scharff, 63).
+
+_FOREIGN DISTRIBUTION:--_
+
+  _Europe_: France; (25): Spain; (12): Sicily; (19): Hertsogovinia;
+     (22): Sweden; (21): Norway; Denmark; Prussia; Germany; Holland;
+     Poland; Austria; Italy; (59): Sardinia; (21).
+
+  _Africa_: Algeria; Tunis; (24).
+
+=Philoscia couchii= Kinahan. PLATE XI.
+
+  1858  _Philoscia couchii_ Kinahan (33), p. 195, pl. XXIII., fig. 4.
+  1868  _Philoscia couchii_ Bate and Westwood (1), p.
+  1885  _Ligidium couchii_ Budde-Lund (8), p. 257.
+  1885  _Philoscia longicornis_ Budde-Lund (8), p. 221.
+  1897  _Philoscia couchii_ Dollfus (21), p. 72, pl. I., fig. 1.
+
+_Philoscia couchii_ is an inhabitant of the sea-side; it is smaller
+than the last species, its colour to the naked eye is a uniform
+lead-grey, and its antennæ are very large (compared with its size) and
+hairy.
+
+This species was discovered by Professor Kinahan when in the company of
+Messrs. Bate and Westwood near Polperro in Cornwall in the year 1858,
+and dried specimens presented by him are in the British Museum (Natural
+History).
+
+_BRITISH LOCALITIES:--_
+
+  _England_: Talland Cove; Polperro; (Bate and Westwood, 1): Salcombe,
+     Devon; (Norman, 49): Meadefoot, Torquay; (Stebbing in 49).
+
+_FOREIGN DISTRIBUTION:--_
+
+  _Europe_: France; (25): Spain; (12): Sicily; (19): Sebastopol;
+     (Norman, 49).
+
+  _Africa_: Azores; Canaries; Morocco; Algiers; Tunis: Egypt
+     Senegal; (24).
+
+  _Atlantic Isles_: Canaries; Azores; (21).
+
+  _Asia_: Syracuse; Bazone (18).
+
+[Illustration: FIG. 45.--FLAGELLUM AND LAST PEDUNCULAR JOINT OF THE
+ANTENNA OF _Philoscia couchii_.]
+
+_Genus_--=PLATYARTHRUS= Brandt, 1833 (3), p. 174.
+
+[_Typhloniscus_ Schöbl (66), p. 279.]
+
+_Flagellum with one joint; eyes wanting; abdomen broad; habitat, ants'
+nests._
+
+The broad body, which is much flattened, and the very thick
+antennæ distinguish _Platyarthrus_ from the other small woodlice
+(Trichoniscidæ).
+
+=Platyarthrus hoffmannseggii= Brandt. PLATE XII.
+
+  1833  _Platyarthrus hoffmannseggii_ Brandt (3), p. 174, pl. IV.,
+         fig. 10.
+  1844  _Itea crassicornis_ Koch (34), part 36, pl. V.
+  1860  _Typhloniscus steinii_ Schöbl (66), p. 282.
+  1868  _Platyarthrus hoffmannseggii_ Bate and Westwood (1), p. 464.
+  1898  _Platyarthrus hoffmannseggii_ Sars (59), p. 175, pl. LXXVI.,
+         fig. 2.
+
+Up to the present this is the only woodlouse which has been found in
+the nests of British ants. It is small and oval, its colour is white,
+and its body is covered with tubercles. The edges of its side plates
+are toothed, its flagellum has but a single joint and it has no eyes.
+
+Miss Kate Hall tells us that, if very hungry, ants in captivity will
+kill and eat _Platyarthrus_. With regard to its own food, Lord Avebury
+has favoured us with the opinion that it lives on the spores of the
+lower plants, such as would be found in the ants' nest.
+
+[Illustration: FIG. 46.--FLAGELLUM AND LAST PEDUNCULAR JOINT OF THE
+ANTENNA OF _Platyarthrus hoffmannseggii_.]
+
+_BRITISH LOCALITIES:--_
+
+  _England_: Warley; Hanwell; West Drayton; Langley;
+     Kingston-on-Soar; Bluebell Hill, Maidstone; (W.M.W.): Berkhamsted;
+     Salcombe; Devon; Cheddar Cliffs, Somerset; (Norman, 49): Ide, near
+     Exeter; (Parfitt, 53): Torquay; (Stebbing in 49); Lulworth Cove;
+     (Rev. A. R. Hogan _teste_ Bate and Westwood, 1): Hammersmith;
+     Oxford; Berry Head, Torquay; Plymouth; (Bate and Westwood, 1): In
+     the nest of _Myrmica rubra_, Newton Ferrers (E. E. Lowe).
+
+  _Scotland_: Banff; (Thomas Edward in 49).
+
+  _Ireland_: Leixlip, Co. Dublin; Lismore, Co. Waterford; Glengariff,
+     Co. Cork; (Scharff, 63): Bagenalstown, Co. Carlow; (64).
+
+_FOREIGN DISTRIBUTION:--_
+
+  _Europe_: France; (28): Spain; (12): Denmark; Germany; Holland;
+     Bohemia; Austria; Tyrol; Helvetia; (59).
+
+       *       *       *       *       *
+
+  NOTE.--In the genera which follow, air-tubes or air-cavities
+     (tracheæ) are present in the outer plates of the abdominal
+     appendages, 1 and 2, or 1 to 5. The appendages in question have
+     in consequence a milk-white appearance in the living animal
+     owing to the fact that the enclosed air reflects white light.
+     Considerable interest attaches to the study of these tracheæ,
+     which have the same function as those of insects, but which have
+     been independently developed. To emphasise the latter fact the
+     structures are often termed "pseudotracheæ."
+
+_Genus_--=PORCELLIO= Latreille, 1804 (37), p. 45.
+
+_Flagellum, with two joints; abdomen, broad; frontal lobe projecting._
+
+_Porcellio_ is easily separated from the previous genera--_Oniscus_,
+_Philoscia_, and _Platyarthrus_--by its two-jointed flagellum. The
+fact that the abdomen is not abruptly narrowed separates it from
+_Metoponorthus_, which also lacks the prominent frontal lobe so
+characteristic of _Porcellio_. The species of this genera might be
+confused with _Cyclisticus_ which has two joints to the flagellum and
+a broad abdomen, but the latter genus has the power of rolling itself
+into a ball, while its frontal lobe is very small, and the first
+segment of its thorax is comparatively larger than in any species of
+_Porcellio_.
+
+=Porcellio scaber= Latreille. PLATE XIII.
+
+  1804  _Porcellio scaber_ Latreille (37), p. 45.
+  1818  _Oniscus granulatus_ Lamark (36), p. 261.
+  1818  _Porcellio nigra_ Say (62), p. 432.
+  1840  _Porcellio brandtii_ Milne-Edwards (46), p. 168.
+  1840  _Porcellio dubius_ Koch (34), part 34, pl. VIII.
+  1847  _Porcellio asper_ Koch (35), p. 207, pl. VIII., fig. 98.
+  1857  _Porcellio montezumæ_ Saussure (60), p. 207.
+  1865  _Porcellio paulensis_ Heller (31), p. 136, p. XII., fig. 5.
+  1868  _Porcellio scaber_ Bate and Westwood (1), p. 475.
+  1876  _Porcellio graniger_ Miers (44), p. 223.
+  1885  _Porcellio graniger_ Budde-Lund (8), p. 149.
+  1898  _Porcellio scaber_ Sars (59), p. 176, pl. LXXVII.
+
+The body of _Porcellio scaber_ is densely covered with tubercles. Its
+colour is usually of a very dark grey, but at times it is quite red or
+variegated with yellow. Albino specimens have been recorded. The two
+joints of the flagellum are of the same length and together equal that
+of the last joint of the peduncle. Air-tubes are present in the outer
+plates of the first two abdominal appendages.
+
+[Illustration: FIG. 47.--FLAGELLUM AND LAST PEDUNCULAR JOINT OF THE
+ANTENNA OF _Porcellio scaber_.]
+
+_BRITISH LOCALITIES:--_
+
+  _England_: High Beach, Epping; Warley; Brightlingsea; (W.M.W.):
+     Maldon; (W.M.W. from R.M.): Langley; Kew; Skirmett; Pamber Forest;
+     (W.M.W.): Liphook; (C.S.): Stoke-on-Trent; Kingston-on-Soar;
+     (W.M.W.)
+
+  _Scotland_: Dinnet (W.M.W. from Madame Christen).
+
+  _Ireland_: Common everywhere; (Scharff, 63.)
+
+_FOREIGN DISTRIBUTION:--_
+
+  _Europe_: Throughout; (59): France; (28): Spain; (15): Iceland;
+     (59): Faroe Isles--Thorsharn and Naalsoe--(R.F.S. and B.M., N.
+     Annadale).
+
+  _America_: Greenland; North America; Sandwich Isles; (B.M.);
+     Mexico; (59): St. Paul; St. Croix; (59); Ascension; Tristan
+     d'Acunha; (23)
+
+  _Asia_: Ceylon; Kamtschatka: (23).
+
+  _Australia_: Melbourne; Sydney; Tasmania; New Zealand; (B.M.,
+     Chilton).
+
+  _Africa_: Azores; Canaries; Cape of Good Hope; (24).
+
+=Porcellio pictus= Brandt and Ratzeburg. PLATE XIV.
+
+  1833  _Porcellio pictus_ Brandt and Razteburg (4), p. 78, pl. 12,
+         fig. 5.
+  1839  _Porcellio melanocephalus_ Koch (34), part 28, pl. XVIII.
+  1853  _Porcellio melanocephalus_ Schnitzler (65), p. 24.
+  1856  _Porcellio mixtus_ Fitch (29), p. 120.
+  1868  _Porcellio pictus_ Bate and Westwood (1), p.
+  1898  _Porcellio pictus_ Sars (59), p. 177. pl. LXXVII., fig. 1.
+
+There are tubercles on the body of _Porcellio pictus_, which is a
+striking looking animal. Its head is black with the lateral lobes
+curved outwards; there is a dark band down the middle of the back and
+commonly two others on each side, with more or less conspicuous yellow
+markings between.
+
+The distal (terminal) joint of the flagellum is but half the length of
+the proximal one and the last peduncular joint is longer than the two
+combined.
+
+The abdominal appendages--1 and 2--are provided with air-tubes.
+
+[Illustration: FIG. 48.--FLAGELLUM AND LAST PEDUNCULAR JOINT OF THE
+ANTENNA OF _Porcellio pictus_.]
+
+_BRITISH LOCALITIES:--_
+
+  _England_: Maldon; (W.M.W. from R.M.): Chislehurst; (Bate and
+     Westwood, 1): Cooper's Hill, near Cheltenham; (Norman, 49):
+     Exeter; (Parfitt, 53): Kent; (Bate and Westwood, 1.)
+
+  _Scotland_: Between Leith and Portobello; (Scott, 68): Cumbrae
+     (Scott, 68a): Ayrshire; (Boyd in Norman, 49): Banff; (T. Edwards
+     in Norman, 49).
+
+  _Ireland_: Dublin; Belfast; (Bate and Westwood, 1): Galway;
+     Maryborough; Queen's Co., Castel; and Caher Co. Tipperary; (R.F.S.)
+
+_FOREIGN DISTRIBUTION:--_
+
+  _Europe_: France; (25): North, West-Central, and East Europe; (8):
+     Sweden; Norway; Denmark; Germany; Hungary; Russia; (59).
+
+  _North America_: (8).
+
+=Porcellio dilatatus= Brandt. PLATE XV.
+
+  1833  _Porcellio dilatatus_ Brandt and Ratzeburg (4), p. 78, pl. 12.,
+         fig. 6.
+  1840  _Porcellio scaber_ Milne-Edwards (not Latreille) (46), p. 167.
+  1868  _Porcellio dilatatus_ Bate and Westwood (1), p.
+  1898  _Porcellio dilatatus_ Sars (59), p. 179, pl. LXXVII., fig. 2.
+
+The fact that _Porcellio dilatatus_ is more than half as broad as it is
+long, at once distinguishes it from the other species of _Porcellio_.
+It is tuberculated and of somewhat a lighter grey than _Porcellio
+scaber_ usually is. The two species agree in having the two joints of
+the flagellum equal, but the last peduncular joint, as in _Porcellio
+pictus_, is longer than the flagellum.
+
+As in the two preceding species, air-tubes are found in the outer
+plates of the appendages on the first two abdominal segments.
+_Porcellio dilatatus_ is to be looked for near houses.
+
+[Illustration: FIG. 49.--FLAGELLUM AND LAST PEDUNCULAR JOINT OF THE
+ANTENNA OF _Porcellio dilatatus_.]
+
+_BRITISH LOCALITIES:--_
+
+  _England_: Maldon; (W.M.W. from R.M.): Eton; (Stebbing from
+     W.M.W., 71a): Berkhamsted; (Norman, 50): Headley, Surrey; Ventnor;
+     (Stebbing in Norman, 49).
+
+  _Ireland_: Dublin; (Scharff, 63): Dundrum; (Scharff in Norman,
+     50): Galway; Roundstone; (R.F.S.): Belfast; (C. W. Buckle, Irish
+     Nat., Vol. XI. (1902), p. 43).
+
+_FOREIGN DISTRIBUTION:--_
+
+  _Europe_: France; (25): Spain; (12 ): Denmark; Norway; Germany;
+     Poland; Holland; (59).
+
+  _Africa_: Madeira; Azores; (24).
+
+  _Australia_: New Guinea; (59).
+
+=Porcellio rathkei= Brandt. PLATE XVI.
+
+  1833  _Porcellio rathkei_ Brandt (3), p. 177, fig. 10.
+  1833  _Porcellio ferrugineus_ Brandt (3), p. 178.
+  1840  _Porcellio trilineatus_ Koch (34), part 34, pl. IX.
+  1853  _Porcellio trivittatus_ Lereboullet (39), p. 54, pl. I.,
+         figs. 13 and 14.
+  1853  _Porcellio tetramoerus_ Schnitzler (65), p. 24.
+  1853  _Porcellio striatus_ Schnitzler (65), p. 24.
+
+There is often a light band down the back and one on either side of it
+near the margin in _Porcellio rathkei_ (especially in the males), with
+other more irregularly arranged light patches between. Unlike the three
+species previously considered, the present one has a smooth body. The
+distal joint of the flagellum is the longer, and the flagellum itself
+is equal in length to the last joint of the peduncle.
+
+Some specimens found by Mr. Webb in 1899 at Eton were submitted to Mr.
+Stebbing, and since then the former has found _Porcellio rathkei_ to
+be pretty generally distributed in West Middlesex, where the species
+appears to frequent the open fields.
+
+Air-tubes occur in abdominal appendages 1 to 5 and the white appearance
+of all of these at once serves to distinguish the living animal from
+_Porcellio scaber_ in which the first two pairs of abdominal appendages
+alone are white.
+
+_BRITISH LOCALITIES:--_
+
+  _England_: Eton; (Stebbing, 71a): Lane End; (Stebbing, from the
+     Misses Johnston, 71a): Acton; Ealing; Hanwell; Southall; Northolt;
+     Greenford; West Drayton; Mortlake; (W.M.W.); Sunderland; (Brady,
+     50a).
+
+_FOREIGN DISTRIBUTION:--_
+
+  _Europe_: France; (25): Bosnia; Servia; (22): Hertzogovania
+     (B.M.); Norway; Northern, Western, and Middle Europe, everywhere;
+     (59): Corfu (B.M.)
+
+  _Asia_: Transcaucasia; (59).
+
+  _North America_: (59).
+
+[Illustration: FIG. 50.--FLAGELLUM AND LAST PEDUNCULAR JOINT OF THE
+ANTENNA OF _Porcellio rathkei_.]
+
+=Porcellio laevis= Latreille. PLATE XVII.
+
+  1804  _Porcellio laevis_ Latreille (37), p. 46.
+  1827  _Porcellio degeerii_ Savigny and Audouin (61), p. 289.
+  1833  _Porcellio cucercus_ Brandt (3), p. 177.
+  1833  _Porcellio syriacus_ Brandt (3), p. 178.
+  1833  _Porcellio musculus_ Brandt (3), p. 180.
+  1833  _Porcellio cinerascens_ Brandt (3), p. 178.
+  1833  _Porcellio dubius_ Brandt (3), p. 178.
+  1837  _Porcellio poeyi_ Guérin (30), p. 6.
+  1844  _Porcellio urbicus_ Koch (34), part 36, pl. IV.
+  1847  _Porcellio flavipes_ Koch (35), p. 206, pl. VIII., fig. 97.
+  1853  _Cylisticus laevis_ Schnitzler (65), p. 25.
+  1857  _Porcellio cubensis_ Saussure (60), p. 307.
+  1857  _Porcellio sumichtasli_ Saussure (60), p. 307.
+  1857  _Porcellio cotillæ_ Saussure (60), p. 307.
+  1857  _Porcellio aztecus_ Saussure (60), p. 307.
+  1857  _Porcellio mexicanus_ Saussure (60), p. 307.
+
+Another smooth species is _Porcellio laevis_. The colour of its body
+is light grey with irregular white markings. The large size of this
+species and the very long tail-appendages of the males are features
+which will help to identify it. The distal joint of the flagellum is
+slightly the longer and as in the last species (_P. rathkei_) the
+flagellum is equal in length to the last joint of the peduncle. The
+chief habitats for this species are among vegetable rubbish near human
+dwellings.
+
+Only the first two abdominal appendages contain air-tubes.
+
+[Illustration: FIG. 51.--FLAGELLUM AND LAST PEDUNCULAR JOINT OF THE
+ANTENNA OF _Porcellio laevis_.]
+
+_BRITISH LOCALITIES:--_
+
+  _England_: Maldon; (W.M.W. from R.M.): Ipswich (1892); Hanwell;
+     Wimbledon; (W.M.W.): Kent; (Kinahan, 32).
+
+  _Ireland_: Dublin; (Bate and Westwood, 1): Blackrock Dundrum; Co.
+     Dublin; Galway; (R.F.S.)
+
+_FOREIGN DISTRIBUTION:--_
+
+  _Europe_: France; (25): Spain; (15): Sicily; (19): Hertzogovania;
+     (22): Sweden; Denmark; Germany; Belgium; Austria; Italy; Dalmatia;
+     Greece; Turkey; (59); Corfu; (B.M.): Inca, Majorca (23);
+     (B.M.--Pocock and Thomas.)
+
+  _Asia_: Syria; Turkestan; (21).
+
+  _Africa_: Morocco; Algeria; Tunis; Tripoli; Senegal; Egypt; (23).
+
+  _Atlantic Isles_: Bermudas; Azores; Canaries; Cape Vera; Madeira;
+     (24).
+
+  _America_: North America; Mexico; Peru; Brazil; Chili; West
+     Indies; Pacific Islands; (59); Sandwich Isles; (B.M.)
+
+=Porcellio ratzeburgii= Brandt. PLATE XVIII.
+
+  1833  _Porcellio ratzeburgii_ Brandt, (3), p. 178.
+  1839  _Porcellio nemorensis_ Koch (34), part 28, pl. XIX.
+  1839  _Porcellio lugubris_ Koch (34), part 28, pl. XX.
+  1853  _Porcellio quercum_ Schnitzler (65), p. 24.
+  1898  _Porcellio ratzeburgii_ Sars (59), p. 182, pl. LXXX, fig. 1.
+
+There are granulations on the middle of the segments in _Porcellio
+ratzeburgii_ and the sides of its body are more nearly parallel than
+in the other species of _Porcellio_; the frontal lobe is, practically
+speaking, semicircular and the lateral plates of the thorax flank the
+head to a considerable extent. As in _Porcellio pictus_, the dark band
+is in the middle of the back. The distal joint of the flagellum is
+nearly twice as long as the proximal, and the flagellum is shorter than
+the last joint of the peduncle. This species was added to the British
+list by Mr. Webb (74) in 1898.
+
+_Porcellio ratzeburgii_ agrees with _Porcellio rathkei_ in having
+air-tubes in the first five abdominal appendages.
+
+[Illustration: FIG. 52.--FLAGELLUM AND LAST PEDUNCULAR JOINT OF THE
+ANTENNA OF _Porcellio ratzeburgii_.]
+
+_BRITISH LOCALITIES:--_
+
+  _England_: Warley; Brightlingsea; young examples (W.M.W.): Maldon;
+     young examples (W.M.W. from R.M.)
+
+_FOREIGN DISTRIBUTION:--_
+
+  _Europe_: Trafoi St. Martini, and Capitello, in the Tyrol;
+     (Norman, 50); East Alps, very common; Val-de-Joux; Massif de la
+     Chartreuse Vaulnaveys (25): Bosnia; (22): Norway; Central Europe;
+     Upper Pfaltz; Bohemia; Saxony; Rhaetia; (59).
+
+_Genus_--=METOPONORTHUS= Budde-Lund, 1879 (7), p. 4. _Porcellionides_
+Miers, 1876 (44), p. 98.
+
+_Flagellum, with two joints; abdomen, narrow; frontal lobe not
+developed._
+
+The hinder legs of _Metoponorthus_ are proportionately longer than in
+any other Oniscidæ save _Philoscia_. Both genera have a narrow abdomen,
+but _Philoscia_ has an extra joint to the flagellum, and shows no sign
+of lateral lobes to the head.
+
+=Metoponorthus pruinosus= Brandt. PLATE XIX.
+
+  1833  _Porcellio pruinosus_ Brandt (3), p. 181.
+  1840  _Porcellio truncatus_ Milne-Edwards (46), p. 173.
+  1840  _Porcellio maculicornis_ Koch (34), part 34, pl. XVI.
+  1853  _Porcellio frontalis_ Lereboullet (39), p. 63, pl. I, fig. 17.
+  1868  _Porcellio pruinosus_ Bate and Westwood (1), p. 487.
+  1877  _Porcellio (Porcellioides) flavo-vittatus_ Miers (45), p. 669,
+         pl., LXVIII., fig. 4.
+  1898  _Metoponorthus pruinosus_ Sars (59), p. 184, pl. LXXX., fig. 2.
+
+Undamaged specimens of _Metoponorthus pruinosus_ are of a beautiful
+bluish-grey colour, owing to a "bloom" which is easily brushed off,
+revealing a dark reddish-brown tint beneath it. The antennæ are long
+and have white markings upon them.
+
+Air-tubes occur in the first two abdominal appendages.
+
+[Illustration: FIG. 53.--FLAGELLUM AND LAST PEDUNCULAR JOINT OF THE
+ANTENNA OF _Metoponorthus pruinosus_.]
+
+_BRITISH LOCALITIES:--_
+
+  _England_: Maldon; (W.M.W. from R.M.): Hanwell; Eton Wick; Kew;
+     Ipswich; Stoke-on-Trent; (W.M.W.): Chiselhurst; Oxford; (Bate and
+     Westwood): Berkhamsted; Burnmoor; Durham; (Norman, 49): Exeter;
+     (Parfitt, 53); Torquay; (B.M.--T.R.R.S.)
+
+  _Scotland_: Banff; (Thomas Edwards in Norman, 49)
+
+  _Ireland_: Dublin; (Kinahan, 32): Foyle District; Donegal; Galway;
+     Clonbrock, Co. Galway; Mornington, Co. Meath; Santry; Gleeson
+     Park; Dundrum, Co. Dublin; Bray; (R.F.S.)
+
+_FOREIGN DISTRIBUTION:--_
+
+  _Europe_: Practically all the Countries of Europe are given in
+     Dollfus' list; (23).
+
+  _Asia_: Japan; China; Syria; Ceylon; Sumatra; Celebes;
+     Phillipines; Caucasus; Himalayas; (23): Christmas Island; (B.M.)
+
+  _Africa_: Generally distributed; Madagascar; Seychelles; (23).
+
+  _Atlantic Isles_; (23).
+
+  _America_: North and South, almost everywhere, to judge from M.
+     Dollfus' list; (23).
+
+  _Australia_: New Caledonia; (23).
+
+=Metoponorthus cingendus= Kinahan. PLATE XX.
+
+  1857 _Porcellio cingendus_ Kinahan (32), p. 279, pl. XIX.,
+        figs. 1468-9.
+  1868 _Porcellio cingendus_ Bate and Westwood (1), p. 489.
+  1885 _Metoponorthus simplex_ Budde-Lund (8), p. 188.
+
+The colour of _Metoponorthus cingendus_ is steel blue with red or
+yellowish spots. It has a raised line across each thoracic segment and
+its abdomen is narrower than in _Metoponorthus pruinosus_.
+
+[Illustration: FIG. 54.--FLAGELLUM AND LAST PEDUNCULAR JOINT OF THE
+ANTENNA OF _Metoponorthus cingendus_.]
+
+_BRITISH LOCALITIES:--_
+
+  _England_: Salcombe, Devon; (Norman, 49): South Devon; (Stebbing
+     in 49).
+
+  _Ireland_: Dublin; (B.M. from Kinahan); Mountain Districts of
+     Dublin, Wicklow, and Cork; Coast of Kerry; Arran Islands; Achill,
+     Co. Mayo; Roundstone, Co. Galway; Mallow, Caef Island; Glandore;
+     Brock Haven, Co. Cork; Killoughrim Forest, Co. Wexford; Kenmare,
+     Co. Kerry; (R.F.S.).
+
+_FOREIGN DISTRIBUTION:--_
+
+  _Europe_: France; (25): Spain; (12).
+
+  (2.) Able to roll up into a ball.
+
+_Genus_--=CYLISTICUS= Schnitzler, 1853 (65), p. 24.
+
+_Flagellum, with two joints; abdomen broad; frontal lobe, very small._
+
+The characters given immediately above are almost those of _Porcellio_
+with which _Cylisticus_ might, perhaps, be confounded. The latter
+has the power, however, of rolling itself into a ball, and the first
+segment of the thorax is comparatively larger than in any species of
+_Porcellio_, indeed the side plates of the segment in question entirely
+flank the head. These features, as well as the straight sides of the
+body and the arched back, connect _Cylisticus_ with _Armadillidium_,
+from which the former is, however, at once separated by its long
+pointed tail appendages.
+
+=Cylisticus convexus= De Geer. PLATE XXI.
+
+  1778  _Oniscus convexus_ De Geer (10), p. 553, pl. XXXV., fig. 11.
+  1833  _Porcellio spinifrons_ Brandt (3), p. 177.
+  1836  _Porcellio laevis_ Koch (34), part 6, pl. I.
+  1853  _Porcellio armadilloides_ Lereboullet (39), p. 65. pl. I.,
+         fig. 18.
+  1853  _Cylisticus laevis_ Schnitzler (65), p. 25.
+  1868  _Porcellio armadilloides_ Bate and Westwood (1), p. 485.
+  1898  _Cylisticus convexus_ Sars (59), p. 186, pl. LXXXI.
+
+There is but a single species of _Cylisticus_ found in this country,
+so that it is not necessary for us to go into much further detail with
+regard to it. _Cylisticus convexus_ has the two joints of the flagellum
+about equal, and they together in turn closely approximate in length to
+the last joint of the peduncle. Mr. Stebbing says, in a letter, that
+British examples do not appear to have the "white tail-piece" seen in
+Continental ones. It is not noticeable in the preserved specimens which
+we have seen from Berkhamsted and Leixlip, but it is very evident in
+the living ones found at Hanwell and Maidstone.
+
+The abdominal appendages 1 to 5 are provided with air-tubes.
+
+[Illustration: FIG. 55.--FLAGELLUM AND LAST PEDUNCULAR JOINT OF THE
+ANTENNA OF _Cylisticus convexus_.]
+
+_BRITISH LOCALITIES:--_
+
+  _England_: Maldon; (W.M.W. from R.M.): Hanwell; Bluebell Hill,
+     Maidstone; Eton; (W.M.W.): Berkhamsted; Portland; (Norman, 49).
+
+  _Scotland_: Salisbury Crags; Edinburgh; Lanarkshire; Rothesay;
+     (Scott, 68): Killwinning; (John Smith _fide_ Robertson, 57):
+     Highgate; (Bate and Westwood, 1).
+
+  _Ireland_: Leixlip, Co. Dublin; Tempo, Co. Fermanagh; Goresbridge,
+     Co. Kilkenny; (R.F.S.)
+
+_FOREIGN DISTRIBUTION:--_
+
+  _Europe_: France; (25): Sweden; Norway; Denmark; Germany; Bohemia;
+     Holland; Belgium; Turkey; Caucasus; (59).
+
+  _North America_; (59).
+
+_Family_--ARMADILLIDIIDÆ.
+
+=Tail appendages not projecting when the animal is walking.=
+
+_Genus_--=ARMADILLIDIUM= Brandt, 1833 (3), p. 184.
+
+_Flagellum, with two joints; outer division of the tail appendages
+expanded and broader at the hinder end._
+
+The members of the genus _Armadillidium_ are more likely to be
+confounded, by the uninitiated, with the "Pill-millipedes" than with
+other Woodlice. Excepting _Cylisticus_ (which has long pointed tail
+appendages) no other British forms have the power of rolling themselves
+up into a complete ball. The very arched body is characteristic of
+_Armadillidium_, and so is the groove into which the basal joints of
+the antennæ fit when the creatures curl up.
+
+The first two abdominal appendages only are provided with air-tubes.
+
+=Armadillidium nasatum= Budde-Lund. PLATE XXII.
+
+  1885  _Armadillidium nasatum_ Budde-Lund (8), p. 51.
+  1892  _Armadillidium nasatum_ Dollfus (14), p. 10, fig. 12.
+  1899  _Armadillidium nasatum_ Norman (misprinted _Porcellidium_) (49),
+         p. 57. pl. VI., figs. 5-8.
+
+_Armadillidium nasatum_ has a narrow but very prominent frontal lobe,
+which is almost square and curves somewhat upwards and backwards. The
+joints of the flagellum are approximately equal, and are together of
+the same length as the last peduncular joint.
+
+The telson is as long as it is broad at the base, and tapers to a
+roundish point, while its sides are slightly incurved.
+
+[Illustration: FIG. 56.--FLAGELLUM AND LAST PEDUNCULAR JOINT OF THE
+ANTENNA OF _Armadillidium nasatum_.]
+
+The outer divisions of the tail appendages are considerably longer than
+broad, and are more or less paddle-shaped.
+
+It will be noticed that the slope from thorax to telson is more gentle
+than in the common species, _Armadillidium vulgare_, and the first
+thoracic segment is not so greatly developed. Consequently the species
+which we are considering does not produce a perfect sphere, and the
+antennæ are not hidden when it rolls up. It is interesting to compare
+this species with _Cylisticus convexus_. The surface of the body is
+smooth, and its colour is a delicate brownish grey with more or less
+distinct rows of darker markings.
+
+_BRITISH LOCALITIES:--_
+
+  _England_: Maldon; (W.M.W. from R.M.): Bluebell Hill, Maidstone
+     (W.M.W.); Clifton, banks of the Avon; (W.M.W. from J.T.C. 1900):
+     Leigh Woods, Clifton; Tunbridge Wells; South Devon; (Stebbing in
+     49); Cheddar Cliffs, Somerset; (Norman, 49).
+
+_FOREIGN DISTRIBUTION:--_
+
+  _Europe_: France; (28): Spain; (12): Italy; (23).
+
+=Armadillidium vulgare= Latreille. PLATE XXIII.
+
+  1804   _Armadillo vulgaris_ Latreille (37), p. 48.
+  1804   _Armadillo variegatus_ Latreille (37).
+  1853   _Armadillo ater_ Schnitzler (65), p. 48.
+  1816   _Armadillo maculatus_ Risso (56), p. 158.
+  1818   _Armadillo pillularis_ Say (62), p. 432.
+  1825   _Armadillo pustulosus_ Dermarest (11), p. 323, pl. XLIX.
+  1830-4 _Armadillidium commutatum_ Brandt and Ratzeburg (4), p. 81,
+          pl. XIII., fig. 123.
+  1833   _Armadillidium zenckeri_ Brandt (3), p. 185.
+  1839   _Armadillo trivialis_ Koch (34), part 28, pl. XIV.
+  1898   _Armadillidium vulgare_ Sars (59), p. 189, pl. LXXXII.
+
+The common pill woodlouse is _Armadillidium vulgare_. Its frontal
+lobe is not large, though it is broad, while its margin where it
+joins the head is rounded and slightly recurved. The proximal joint
+of the flagellum is somewhat the shorter and the two together, as in
+_Armadillidium nasatum_, are of about the same length as the last joint
+of the peduncle.
+
+The telson has the form of a triangle with the angles truncated and is
+about as long as it is broad at the base. The outer divisions of the
+tail appendages are considerably broader than they are long.
+
+The species can roll itself up into a very perfect sphere, and when
+it assumes this form its antennæ are hidden beneath the much expanded
+lateral plates of the first thoracic segment.
+
+[Illustration: FIG. 57.--FLAGELLUM AND LAST PEDUNCULAR JOINT OF THE
+ANTENNA OF _Armadillidium vulgare_.]
+
+The body is smooth, shiny, and strongly arched. Its colour varies very
+considerably, generally it is of a slaty-grey, but yellow markings are
+often present to a greater or less extent. In a specimen before us
+(from Bluebell Hill, Maidstone) the head is of a uniform dark grey,
+the sides of the thorax are yellow, while the back is mottled with the
+same colour. The abdomen, including the telson, is also yellow with the
+exception only of the tail appendages, which are dark grey.
+
+_BRITISH LOCALITIES:--_
+
+  _England_: Warley; (W.M.W): Maldon; (W.M.W. from R.M.):
+     Brightlingsea; Hanwell; Mortlake; Bluebell Hill, Maidstone;
+     Langley; Skirmett; Pamber Forest; Kingston-on-Soar; Ipswich;
+     (W.M.W.); Lynmouth; (W.M.W. from J.T.C.)
+
+  _Scotland_: (Scott, 68.)
+
+  _Ireland_: Ardrahan; (Norman, 50): Borris, Co. Carlow; Glandare,
+     Terneay, Co. Cork; Courtstown, Co. Wexford; Cappagh, Co.
+     Waterford; Castel, Co. Tipperary; (R.F.S.)
+
+_FOREIGN DISTRIBUTION:--_
+
+  _Europe_: Throughout; (23).
+
+  _Asia_: Damascus; (23).
+
+  _Africa_: Algeria; (23).
+
+  _Atlantic Isles_: (23).
+
+  _America_: North and South; (23).
+
+  _Australia_: Melbourne (64 quoting Budde-Lund); New Zealand; (23).
+
+=Armadillidium pulchellum= Zencker. PLATE XXIV.
+
+  1799  _Oniscus pulchellus_ Zencker (78) (quoted by Koch in Panzer),
+         part 62, pl. XXI.
+  1833  _Armadillidium pulchellum_ Brandt (3), p. 188.
+  1861  _Armadillo maculatus_ Sill (69), p. 5.
+  1870  _Armadillidium pictum_ Plateau (not Brandt) (55), p. 116.
+  1898  _Armadillidium pulchellum_ Sars (59), p. 191, pl. LXXXIII.,
+         fig. 4.
+
+The smallest British species is _Armadillidium pulchellum_. The frontal
+lobe projects so as to make the head somewhat triangular. The antennæ
+are very short and the distal joint of the flagellum is three times the
+length of the other, while the two together are not as long as the last
+peduncular joint.
+
+[Illustration: FIG. 58.--FLAGELLUM AND LAST PEDUNCULAR JOINT OF THE
+ANTENNA OF _Armadillidium pulchellum_.]
+
+The telson is truncated at the end so that it is by no means as long as
+it is broad at the base, and the outer divisions of the tail appendages
+are in similar proportion.
+
+The colour of the body (which is smooth) is dark brown with four
+important series of light patches running down the back and less marked
+variegations between them.
+
+_BRITISH LOCALITIES:--_
+
+  _England_: Matlock; (T.R.R.S.) Arnside; Westmorland (Brady, 50a).
+
+  _Ireland_: Ballymote, (Irish Nat., May, 1901), Sligo; (Scharff).
+
+_FOREIGN DISTRIBUTION:--_
+
+  _Europe_: Vosges; Switzerland; Pyrenees; (23): Forest de Soignes;
+     Belgium; (14).
+
+=Armadillidium depressum= Brandt. PLATE XXV.
+
+  1833  _Armadillidium depressum_ Brandt (3), p. 82. pl. XII.,
+         figs, 4, 5, 6, C, D.
+  1892  _Armadillidium depressum_ Dollfus (14), p. 17-18.
+
+The frontal lobe in _Armadillidium depressum_ is very prominent and
+much recurved. The antennæ are fairly long and while the two joints
+of the flagellum are nearly equal they are together not so long as
+the last peduncular joint.
+
+[Illustration: FIG. 59.--FLAGELLUM AND LAST PEDUNCULAR JOINT OF THE
+ANTENNA OF _Armadillidium depressum_.]
+
+The telson is slightly longer than it is broad at the base, and its
+sides are incurved. As in _Armadillidium vulgare_ and _Armadillidium
+pulchellum_ the outer divisions of the tail appendages are broader
+than they are long.
+
+The body is flatter than in the other species and bears tubercles; its
+colour is a slate-grey with yellowish markings. The first thoracic
+segment is well developed and the head appears as if almost completely
+imbedded in it.
+
+_BRITISH LOCALITIES:--_
+
+  _England_: Clifton, banks of the Avon; (W.M.W. from J.T.C., 1900):
+     Shirehampton, near Bristol; (Stebbing in 49): Clifton; (Dollfus
+     from Miers 14).
+
+_FOREIGN DISTRIBUTION:--_
+
+  _Europe_: France; Italy; (25): Asia Minor; (14, quoting Brandt).
+
+=Distribution of Species.= There are not sufficient records at present
+to enable us to draw any conclusions as to the general distribution of
+Woodlice in the British Isles, but it is hoped that more attention will
+be given to these creatures, and that before long there may be other
+material available.
+
+=Conclusion.= At the beginning it was mentioned that the present work
+grew out of an investigation into the fauna of Essex, and in order
+to show what may be expected when places are explored in which no
+collecting has been done, we may briefly indicate the results which we
+obtained in the county in question.
+
+It was not long before a species new to Britain--to wit, _Porcellio
+ratzeburgii_--was found (74). This discovery was mentioned by Mr.
+Stebbing in the _Victoria County History of Essex_ (p. 71), and he
+prophesied that most of the British species then would be met with in
+the county. We may safely claim to have shown that his prediction was
+true, for we have been able to record in the preceding pages no less
+than sixteen other species, as will be seen from the following lists:--
+
+_WOODLICE RECORDED FROM ESSEX._
+
+  1. _Ligia oceanica_
+  2. _Ligidium hypnorum_
+  3. _Trichoniscus pusillus_
+  4. _Trichoniscus roseus_
+  5. _Haplophthalmus danicus_
+  6. _Oniscus asellus_
+  7. _Philoscia muscorum_
+  8. _Platyarthrus hoffmannseggii_
+  9. _Porcellio scaber_
+  10. _Porcellio pictus_
+  11. _Porcellio dilatatus_
+  12. _Porcellio laevis_
+  13. _Porcellio ratzeburgii_
+  14. _Metoponorthus pruinosus_
+  15. _Cylisticus convexus_
+  16. _Armadillidium nasatum_
+  17. _Armadillidium vulgare_
+
+Of these _Ligidium hypnorum_ calls for special mention, as it had not
+been found in this country since Mr. Stebbing discovered it in Surrey
+in 1873. Several of the Porcellios and _Cylisticus convexus_ have been
+met with in but few places, and the same may be said of _Armadillidium
+nasatum_.
+
+Of the British species not as yet found in Essex _Trichoniscus vividus_
+has at present only been recorded from Ireland; _Philoscia couchii_ and
+_Armadillidium depressum_ have not been collected except in the extreme
+south west of England, while _Metoponorthus cingendus_ has hitherto
+only been noticed in Devonshire and Ireland. The other four species,
+with the exception of _Porcellio rathkei_, which is well distributed
+in west Middlesex (and might have been expected to occur in Essex),
+are still rare. In fact, for _Trichoniscoides albidus_ but two British
+localities are known; for _Haplophthalmus mengii_ three (two in England
+and one in Ireland); while _Armadillidium pulchellum_ has only been
+recorded from two or three places.
+
+In other counties quite as satisfactory results were obtained as in
+Essex--a systematic search in Buckinghamshire brought to light at Eton
+three species which at the time had not been recorded from the British
+Isles, while in Middlesex, no less than a dozen species were found at
+Hanwell.
+
+Since part of this contribution was printed our attention has been
+drawn to some notes by the Rev. Canon Norman and Professor G. S. Brady
+(50a). These bear out the remarks which have already been made, for
+among the species found by Professor Brady in the north of England
+were _Trichoniscoides albidus_, _Haplophthalmus mengii_, _Porcellio
+rathkei_, and _Armadillidium pulchellum_. In one of Canon Norman's
+previous papers (50--1903) he claims to have added the second species
+to the British list, and in the notes in question a similar claim is
+made with regard to the first and third. It should, however, be pointed
+out that all three of them were found in Buckinghamshire in 1899 by Mr.
+Webb, and that they were exhibited at the Nature Study Exhibition held
+in London in August, 1902. A specimen of _Armadillidium pulchellum_
+from Matlock was sent to us by the Rev. T. R. R. Stebbing in January,
+1904, and was found, we understand, some considerable time previously.
+
+It only remains for us to express our hearty thanks to the numerous
+friends and correspondents who have given us their ready help. The
+names of these have been printed in the text, but we would like to
+mention more particularly Dr. Calman, of the British Museum (Natural
+History), Monsieur Adrian Dollfus, Mr. Roland Matthams, the Rev. Canon
+Norman, Dr. Scharff, the Rev. T. R. R. Stebbing, and Miss Willmott.
+
+
+FOOTNOTES:
+
+[1] "The Non-Marine Molluscs of Essex," by Wilfred Mark Webb; ESSEX
+NATURALIST, Vol. x. (1897), pp. 27-48 and 65-81.
+
+[2] The numbers in brackets refer to papers mentioned in the
+Bibliography at the end.
+
+[3] It should be pointed out that the methylated spirit now sold in the
+shops contains mineral naphtha and goes milky on the addition of water.
+Permission can be obtained from Somerset House to buy what is still
+called "ordinary methylated spirit," but at present five gallons has to
+be purchased at one time.
+
+
+
+
+BIBLIOGRAPHY.
+
+
+Explanation of the initials given in the text:--
+
+  B.M.--Specimens in the British Museum (Natural History).
+  J.T.C.--John Thomas Carrington.
+  J.A.M.--James A. Murie.
+  R.M.--Roland Matthams.
+  R.F.S.--R. F. Scharff.
+  C.S.--Charles Sillem.
+  T.R.R.S.--The Rev. Thomas R. R. Stebbing.
+  W.M.W.--Wilfred Mark Webb.
+  R.W.--R. Welch.
+
+  (1) BATE, C. SPENCE, and WESTWOOD, J.C.: _A history of the British
+        Sessile-eyed Crustacea_, London, 1868.
+
+  (2) BOSC, L. A. G.: _Manuel de l'histoire Naturelle des
+        Crustacés_, Vol. II. Paris, 1830.
+
+  (3) BRANDT, J. F.: "Conspectus Monographiae Crustaceorum
+        Oniscodorum Latreillei," _Bull. Soc. Nat., Moscow._ Vol. VI.
+        (1833), pp. 171-193.
+
+  (4) BRANDT, J. F., and RATZEBURG, J. T. C.: _Medizinische
+        Zoologie._ Vol. II., Berlin, 1830-1834.
+
+  (5) BRUNTZ, L.: "Contribution à l'Etude de l'Excretion chez les
+        Arthropodes." _Archives de Biologie._ Vol. XXII. (Nov., 1903),
+        pp. 215-422, pls. I.-VIII.
+
+  (6) BUDDE-LUND, G.: "Danmarks Isopode Landkrebsdyr,"
+        _Naturhistorisk Tidsskrift._ Part 3, vol. VII. (1870,
+        pp. 217-245).
+
+  (7) BUDDE-LUND, G.: _Prospectus generum specierumque Crustaceorum
+        Isopodum terrestrium._ Copenhagen, 1879.
+
+  (8) BUDDE-LUND, G.: _Crustacea Isopoda Terrestria._ Hauniae, 1885.
+
+  (9) CUVIER, G.: "Memoires sur les Cloportes terrestres." _Journ.
+        d'hist. nat._ Vol. II. 1792.
+
+  (10) DE GEER, C.: _Memoires pour servir à l'histoire des
+         insectes._ Vol. VII., Stockholm, 1778.
+
+  (11) DESMAREST, A.G.: _Considérations générales sur la classe des
+         Crustacés._ Paris, 1825.
+
+  (12) DOLLFUS, A.: "Catalogue raisonné des Isopodes terrestres de
+         l'Espagne." _Ann. Soc. Espan. Hist. Nat._ Vol. XXI. (1892),
+         pp. 161-190.
+
+  (13) DOLLFUS, A.: "Sur la Distribution Geographique des Isopodes
+         terrestres dans la region des Basses-Pyrenees." _Assoc.
+         Francaise pour l'avancement des Sciences. Rep. Congress de
+         Pau._, 1892.
+
+  (14) DOLLFUS, A.: "Le Genre Armadillidium." _Feu. des Jeunes
+         Naturalistes_, Ser. 3. May 1892.
+
+  (15) DOLLFUS, A.: "Catalogue raisonné des Isopodes terrestres de
+         l'Espagne." Premier supplement, _Ann. Soc. Espan. Hist. Nat._
+         Vol. XXII. (1893), pp. 47-51.
+
+  (16) DOLLFUS, A.: "Isopodes Terrestres in 'Voyage de M. Ch.
+         Allmand aux Iles Canaries.'" _Mem. Soc. Zool. de France._
+         Vol. VI. (1893), p. 46.
+
+  (17) DOLLFUS, A.: "Sur la Distribution Geographique des
+         Armadilliens en Europe." _Compte-Rendu troisieme Congres.
+         Internal. de Zool._ Leyden, Sept. 1895 (1896), pp. 356-358.
+
+  (18) DOLLFUS, A.: "Les Isopodes terrestres du Nord de l'Afrique du
+         Cap. Blanc a Tripoli." _Mem. Soc. Zool. Trans._ Vol. IX.
+        (1896), pp. 523-553.
+
+  (19) DOLLFUS, A.: _Crustacés Isopodes de la Sicile._ 1896.
+
+  (20) DOLLFUS, A.: "On West Indian Isopod Crustaceans." _Proc.
+         Zool. Soc. Lond._ 1896, pp. 388-400.
+
+  (21) DOLLFUS, A.: "Tableau Iconographique des _Philoscia_
+         d'Europe." _Feu. des Jeun. Natural._ Ser. 3, 1897, pp. 70-73
+         and 91-95.
+
+  (22) DOLLFUS, A.: "Land Isopods der Balkan region." _Wissenschaft
+         Mittheilung aus Bosnien und der Hercegovina._ Vol. IV. (1896).
+
+  (23) DOLLFUS, A.: "Les Crustacés Isopodes Terrestres à grande
+         dispersion," _Feu des Jeun. Natural._ Ser. 3 (Oct. 1897).
+
+  (24) DOLLFUS, A.: "Sur la Distribution Geographique des Isopodes
+         Terrestres dans l'Afrique Septentrional du Senegal à Obock."
+         _Proc. Inter. Congres. Zool._ Cambridge, 1898, pp. 249-259.
+
+  (25) DOLLFUS, A.: "Catalogue des Crustacés Isopodes Terrestres de
+         France." _Feu. des Jeun. Natural._ Ser. 3 (October 1899).
+
+  (26) FABRICIUS, J.C.: _Entomologia systematica._ Vol. II.,
+         Hauniae, 1793.
+
+  (27) FABRICIUS, J. C.: Supplement to the last, 1798.
+
+  (28) FERNIE, Dr.: _Animal Simples_, 1899.
+
+  (29) FITCH, Asa.: _Noxious Insects of New York._ Albany, 1856.
+
+  (30) GUERIN, F.E.: "Sur _Porcellio Poeyi_." _Ann. Sci. Soc. Entom.
+         de France._ Vol. VI. (Paris, 1837, in Bull. ent., page 6).
+
+  (31) HELLER, C.: _Reise der Novara; Crustacea._ 1865.
+
+  (32) KINAHAN, J.R.: "Analysis of certain genera of terrestrial
+         Isopoda." _Nat. Hist. Rev._ Vol. IV. (1857).
+
+  (33) KINAHAN, J.R.: "On the genera _Philoscia_, _Itea_ and
+         _Philougria_." _Nat. Hist. Rev._ Vol. V. 1858.
+
+  (34) KOCH, C.L.: _Deutschlands Crustaceen, Myriapoden and
+         Arachniden._ Regensburg, 1835-1844.
+
+         Koch's descriptions and figures were published in _Deutschlands
+          Crustaceen_ and appeared also in Panzer's _Faunæ Insectorum
+          Germanicæ_ continued by Herrich-Schäffer (which see). The
+          number of the parts of the latter which correspond to those
+          of the former are placed in square brackets after them in the
+          list here given. Part 6 (1836) [139]; Part 22 (1838) [162];
+          Part 28 (1839) [178]; Part 34 (1840) [180]; Part 36 (1844)
+          [186]. Some of the dates quoted will be found to differ from
+          those usually given (in Budde-Lund (8, p. 7) for instance),
+          and printed on the parts of the copy in the Zoological
+          Society's Library. Our authority for this change is Mr. C. D.
+          Sherborne, who bases his dates upon reviews which he has
+          discovered.
+
+  (35) KOCH, C. L.: _System der Myriapoden mit den Verzeichnissen
+         und Berichtigungen zu Deutschlands Crustaceen, Myriapoden und
+         Arachniden._ Regensburg, 1847.
+
+  (36) LAMARCK, J. B.: _Histoire naturelle des animaux sans
+         vertébres._ Vol. V., 1818.
+
+  (37) LATREILLE, P. A.: _Histoire Naturelle des Crustacés et des
+         Insectes._ Vol. VII., Paris, 1804.
+
+  (38) LEACH, W. E.: "Tabular view of the external characters of
+         four classes of animals, which Linné arranged under Insectes."
+         _Trans. Linn. Soc. Lond._ Vol. XI., 1815.
+
+  (39) LEREBOULLET, A.: "Memoire sur les Crustacés de la famille des
+         Cloportides qui habitent les environs de Strasbourg." _Mem. Soc.
+         Mus. Hist. Nat. Strasbourg._ Vol. IV., 1853, pp. 130, pl. X.
+
+  (40) LEUCKART, R.: _Verzeichnisz der zur Fauna Helgolands
+         gehörenden wirbellosen Seethiere._ Braunsweig, 1847.
+
+  (41) LINNÉ, C.: _Fauna Suecica._ First edition, Holmiæ, 1746.
+
+  (42) LINNÉ, C.: _Fauna Suecica._ Second edition, Holmiæ, 1761.
+
+  (43) LINNÉ, C.: _Systema Naturae_, ed. 12, 1767.
+
+  (44) MIERS, E. J.: "Catalogue of New Zealand Crustacea." _Ann.
+         Mag. Nat. Hist., Ser. 4._, Vol. XVII., 1876.
+
+  (45) MIERS, E. J.: "On a collection of Crustacea (Decapoda and
+         Isopoda), chiefly from South America." _Proc. Zool. Soc._,
+         1877, p. 653-678.
+
+  (46) MILNE-EDWARDS, H.: _Histoire naturelle des Crustacés._ Vol.
+         III. Paris, 1840.
+
+  (47) NICHOLSON and LYDDEKER: _Manual of Palæontology_, 1889, Vol.
+         II., p. 559.
+
+  (48) NORMAN, A. M.: "Note on the discovery of _Ligidium agile_,
+         Persoon (_Zia saundersii_ Stebbing)." _Ann. Mag. Nat. Hist.
+         Ser. 4_, Vol. XI., p. 419.
+
+  (49) NORMAN, A. M.: "British Land Isopoda." _Ann. Mag. Nat. Hist.
+         (Ser. 7)_, Vol. III. (1899), pp. 71-78, pl. VI.
+
+  (50) NORMAN, A. M.: Continuation of the last. Vol. XI., 1903, pp.
+         309-372.
+
+  (50a) NORMAN, A.M.: and BRADY C.S.: "British Land Isopoda." Second
+         Supplement _Ann. Mag. Nat. Hist. (Ser. 7)_, Vol. XIV. (1904),
+         pp. 449-450.
+
+  (51) PANZER, G. W. F.: _Faunæ Insectorum Germanicæ initia, oder
+         Deutschlands Insecten._ Parts 1-110, Nurnberg, 1793-1813.
+        (See Koch.)
+
+  (52) PANZER, G. W. F.: Continuation by Herrich-Schäffer, Parts
+         111-190, 1829-1844. (See Koch.)
+
+  (53) PARFITT, E.: "The Fauna of Devon." Sessile-Eyed Crustacea.
+         _Trans. Devon Assoc. Sci._, Sept. 1873.
+
+  (54) PERSOON: No paper upon Woodlice by this author is known, but
+         he is quoted in Panzer's _Deutschlands Insecten_ (51), which
+         see.
+
+  (55) PLATEAU, F.: "Crustacés Isopodes Terrestres." _Bull. Acad.
+         Roy. de Belgique, Ser. 2._, Vol. XXIX., No. 2 (1870), p. 112.
+
+  (56) RISSO, A.: _Histoire Naturelle des Crustacés des environs de
+         Nice._ Paris, 1816.
+
+  (57) ROBERTSON, D.: "Catalogue of the Amphipoda and Isopoda of
+         the Firth of Clyde." _Trans. Nat. Hist. Soc. Glasgow_, Vol. II.
+         (1888), pp. 9-99.
+
+  (58) ROULE, LOUIS: "Etudes sur le Development de Crustacés." _Ann.
+         Sci. Nat._, Vol. XVIII. (1895), pp. 1-156, pls. I.-X.
+
+  (59) SARS, G. O.: _An account of the Crustacea of Norway._ Vol.
+         II., 1896-1899.
+
+  (60) SAUSSURE, H. de: "Diagnoses de quelques crustacés nouveaux
+         des Antilles et du Mexique." _Rev. et Mag. de Zool. (Ser. 2)_,
+         Vol. IX. (1857), pp. 304-308.
+
+  (61) SAVIGNY, J. C., and AUDOUIN, V.: _Description de l'Egypte._
+         Vol. XXII., 1827.
+
+  (62) SAY, T.: "An account of the Crustacea of the United States."
+         _J. Acad. Nat. Sci. Philadelphia_, Vol. I., pt. II., 1818.
+
+  (63) SCHARFF, R. F.: "The Irish Woodlice." _Irish Naturalist_,
+         Vol. III., 1894, pp. 4-7 and 25-29, pl. II.
+
+  (64) SCHARFF, R. F.: "The Woodlice of Co. Carlow." _Irish
+         Naturalist_, 1895, p. 319.
+
+  (65) SCHNITZLER, H. J.: _De Oniscineis agri Bonnensis._ (Thesis.),
+         Cologne, 1853.
+
+  (66) SCHOBL, J.: "_Typhloniscus_, eine neue blinde Gattung der
+         Crustacea Isopoda." _Sitzungsberichte der math. naturw. Acad.
+         Wiss. Wien._ Vol. XL. (1860), pp. 279-330.
+
+  (67) SCOPOLI, J. A.: _Entomologia Carniolica._ Vindibonæ, 1763.
+
+  (68) SCOTT, T.: "The Land and Freshwater Crustacea of the District
+         around Edinburgh." _Proc. R. Phys. S. Edin._, Vol. XI.
+        (1890-91), p. 75.
+
+  (68a) SCOTT, T.: _British Association Hand Book on the Natural
+         History of Glasgow._ 1901; _Isopoda_, pp. 335 and 336.
+
+  (69) SILL, VICTOR: "Beitrag zur Kentniss der Crustaceen,
+         Arachniden and Myriapoden Siebenburgens." _Verhandl. u.
+         Mittheil. des Siebenburghischen Ver. für Naturwiss. zu
+         Hermannstadt_, Vol. XII. (1861), p. 1-11.
+
+  (70) STEBBING, T. R. R.: "On a Crustacean of the Genus Zia." _Ann.
+         Mag. Nat. Hist. Ser. 4._, Vol. XI. (1873).
+
+  (71) STEBBING, T. R. R.: _The Victoria County History of Essex_
+         (1903); Crustacea, pp. 27-28.
+
+  (71a) STEBBING, T. R. R.: _The Victoria County History of
+         Buckinghamshire_ (1905); Crustacea.
+
+  (72) VEJDOVSKYF: "Zur Morphologie der Antennen und Schalendruse
+         der Crustaceen." _Zeit. Wiss. Zool._, Vol. LXIX., p. 378.
+
+  (73) VERHOEF, K. W.: "Ueber Palæarktische Isopoden." _Zool. Anz._,
+         Vol. XXIV.
+
+  (74) WEBB, WILFRED MARK: "The occurrence in Essex of a species
+         of Woodlouse (Isopoda) new to Britain (_Porcellio ratzeburgii_,
+         Brandt)." _Essex Naturalist_, Vol. XI. (1899), p. 127.
+
+  (75) WEBB, WILFRED MARK: "Notes on Woodlice" (Including extracts
+         from a paper read before the North London Natural History
+         Society by James B. Casserley). _Science Gossip_, Vol. VI.,
+         New Series (1900), pp. 295-296.
+
+  (76) WEBER, MAX.: "Uber einige neue Isopoden der Niederlandischen
+         Fauna." _Tijdschr der Niederland Dierk veren_, Vol. V. (1881),
+         pp. 167-196, pl. V.
+
+  (77) ZADDACH, E. G.: _Synopses crustaceorum Prussicorum prodromus
+         Regiomonti_, 1844.
+
+  (78) ZENKER, C. D.: No paper upon woodlice by this author is
+         known, but he is quoted in Panzer's _Deutschlands Insecten_
+         (51), which see.
+
+  (79) ZITTEL, K. A. von: _Textbook of Palæontology_. English
+         Translation 1900, p. 668.
+
+
+
+
+INDEX.
+
+
+  Abdomen, 2, =2=
+
+  Aegidae, 2
+
+  Air cavities, in abdominal appendages, 31
+
+  Air tubes, 1, 6, 31, 33, 34, 35, 36, 37, 39
+
+  _albidus, Trichoniscoides_, description of, 25
+
+  Alcohol, 16
+
+  Antennae, large, 2, =3=
+
+      "     smaller, 2, =3=
+
+  Alimentary canal, 6, =7=
+
+  Ants, 31
+
+    "   wood, 14
+
+  Anus, 31, inset facing =10=
+
+  Appendages, 2
+
+        "     abdominal, 5, =6=
+
+  _Archaeoniscus brodiei_, 2
+
+  Armadillidæ, 17
+
+        "      characters of, 18, 40
+
+  _Armadillidium_, 15, 38
+
+          "      _commutatum_, 41
+
+          "      _depressum_, 44
+
+          "            "        description of, 43
+
+          "            "        flagellum of, =43=
+
+  _Armadillidium nasatum_, 41, 44, Plate xxii.
+
+          "            "        description of, 40
+
+          "            "        flagellum of, =40=
+
+  _Armadillidium pictum_, 42
+
+          "      _pulchellum_, 43, 44, 45, Plate xxxiv.
+
+          "            "        description of, 42
+
+          "            "        flagellum of, =42=
+
+  _Armadillidium vulgare_, 15, 40, 43, 44, Plate xxiii.
+
+       "           "            description of, 41
+
+       "           "            flagellum of, =41=
+
+       "           "            moulting of, 12, 13
+
+       "         _zenckeri_, 41
+
+  _Armadillo ater_, 41
+
+       "     _maculatus_, 41, 42
+
+       "     _pillularis_, 41
+
+       "     _pustulosus_, 41
+
+       "     _trivialis_, 41
+
+       "     _variegatus_, 41
+
+       "     _vulgaris_, 41
+
+  Arthropoda, 1
+
+  Arteries, 7, =7=
+
+  _asellus, Oniscus_, description of, 27
+
+  Avebury, Lord, 31
+
+
+  Baden, Miocene of, 2
+
+  Bate and Westwood, 17, 19, 30
+
+  Blastoderm, 10
+
+  Body cavity, 11, inset facing =10=
+
+  Brady, Professor C. S., 45
+
+  Branchial nephrocytes, 8
+
+  British Association, 19
+
+  Brood pouch, 4, =5=, 9
+
+  Budde-Lund, 28
+
+
+  Calman, Dr., 45
+
+  Carpenter, 15
+
+  Cells, nucleated, 10, inset facing =10=
+
+  Cephalic nephrocytes, 8
+
+  Cheslip, 15
+
+  Chiselbob, 15
+
+  Church louse, 16
+
+  Cicatricula, 10, inset facing =10=
+
+  _cingendus, Metoponorthus_, description of, 38
+
+  Circulatory system, 6, 7
+
+  Classification, 17
+
+  Coal measures, 1
+
+  Collection of Woodlice, methods of, 16
+
+  Commissures, 8, =8=
+
+  Conclusion, 43
+
+  _convexus, Cylisticus_, description of,39
+
+  _couchii, Philoscia_, description of, 30
+
+  Crabs, land, 1
+
+  Crustacea, 1
+
+  Cud worm, 15, 16
+
+  _Cylisticus_, 40
+
+        "   characters of, 17, 18, 38
+
+  _Cylisticus convexus_, 44, Plate xxi.
+
+        "          "     description of, 39
+
+        "          "     flagellum of, =39=
+
+        "     _laevis_, 35, 39
+
+  _Cymothoa oceanica_, 20
+
+
+  _danicus, Haplophthalmus_, description of, 27
+
+  _depressum, Armadillidium_, description of, 43
+
+  Development, 9
+
+  Digestive glands, 6, =7=
+
+  _dilatatus, Porcellio_, description of, 33
+
+  Distribution of species, 43
+
+  Dollfus, Adrian, 45
+
+
+  Economic considerations, 12
+
+  Egg, 9, 10, =10=, =11=, inset facing =10=
+
+   "   segmentation of, 11, inset facing =10=
+
+  Embryo, 10, =11=
+
+  Endoderm, 10, inset facing =10=
+
+  Essex, Woodlice recorded from, 44
+
+  Excretory organs, 7
+
+  Exhibition of species new to Britain, 45
+
+  Exmoor, woodlice and ants on, 14
+
+  External structure, 2
+
+
+  Flagellum, 3, =3=
+
+  Food, 13, 14
+
+
+  Ganglia, cerebral 8
+
+  Geological history, 1
+
+  Genera, 17
+
+  Gill, 5, =5=
+
+  Gills, 7, =6=
+
+  _Glomeris marginata_, 15
+
+  Grammar sows, 16
+
+  Growth, time required for, 12
+
+  Gullet, 6
+
+  Gut, fore, inset facing =10=
+
+   "   mid, inset facing =10=
+
+
+  Habits, 12
+
+  Hall, Miss Kate M., 31
+
+  _Haplophthalmus_, 22
+
+          "          characters of, 17, 18, 26
+
+          "          _danicus_, 44, Plate viii.
+
+          "               "      description of, 27
+
+          "               "      flagellum of, =27=
+
+          "          _elegans_, 26
+
+          "          _mengii_, 44, 45, Plate vii.
+
+          "              "       description of, 26
+
+          "              "       flagellum of, =26=
+
+  Head, 2, =2=, =3=
+
+  Heart, 6, 7, =7=, 11
+
+  Herefordshire, Old Red Sandstone, 1
+
+  History, geological, 1
+
+  _hoffmannseggii, Platyarthrus_, description of, 30
+
+  Hog-louse, 15
+
+  Hogs, little grey, 16
+
+  Hydro-cyanic acid gas for destroying woodlice, 14
+
+  _hypnorum, Ligidium_, description of, 21
+
+
+  Insects, 1
+
+  Intestine, 6, =7=
+
+      "      formation of, in embryo, 10, 11
+
+  Isle of Wight, Oligocene of, 2, Oolite of, 2
+
+  Isopoda, 1, 19
+
+  _Itea crassicornis_, 30
+
+     "   _laevis_, 22
+
+     "   _mengii_, 26
+
+     "   _rosea_, 24
+
+     "   _riparia_, 22
+
+     "   _vivida_, 23
+
+
+  Jurassic, Upper, 2
+
+
+  Kinahan, Professor, 19, 28, 30
+
+  Kitchenball, 15
+
+
+  Labels, 16
+
+  _laevis, Porcellio_, description of, 35
+
+  _Ligia_, 21
+
+      "    branchial nephrocytes, 8
+
+      "    characters of, 17, 18, 19, 20
+
+      "    _hypnorum_, 21
+
+      "    _melanocephala_, 29
+
+      "    _oceanica_, 44, Plate i.
+
+      "        "       description of, 20
+
+      "        "       excretory organs of, 7, 8
+
+      "        "       flagellum of, 20, =20=
+
+      "    _scopulorum_, 20
+
+  Ligiae, 17
+
+     "    characters of, 19
+
+  Ligiidae, characters of, 17, 18, 19
+
+  _Ligidium_, 19
+
+      "       characters of, 17, 18, 21
+
+      "       _hypnorum_, 44, Plate ii.
+
+      "            "      description of, 21
+
+      "            "      excretory organs of, 7
+
+      "            "      in Surrey, 19
+
+      "       _persoonii_, 21
+
+  Lip, the lower, 4, =5=
+
+   "   the upper, 4, =5=
+
+  Lucre pig, 15
+
+  Lugdor, 15
+
+
+  Mandibles, 3, =4=
+
+  Manure, from stables, favourable to woodlice, 14
+
+  Maxillae, first, 3, =4=
+
+     "      second, 3, =4=
+
+     "      openings of excretory organs on second, 7
+
+  Maxillipeds, 3, =4=
+
+  _mengii, Haplophthalmus_, description of, 26
+
+  Mesoderm, 10, inset facing =10=
+
+  Methylated spirit, 16
+
+  _Metoponorthus_, 21
+
+         "          characters of, 18, 37
+
+         "          _cingendus_, description of, 38, Plate xx.
+
+         "                 "     flagellum of, =38=
+
+         "          _pruinosus_, 44, Plate xix.
+
+         "                "     description of, =37=
+
+         "                "     flagellum of, 37
+
+         "          _simplex_, 38
+
+  Miocene, 2
+
+  Middlesex, West, 35
+
+  Millipede, pill, 15, 40
+
+  Moult, 11
+
+  Moulting, process of, 12, 13, 14
+
+  Mouth appendages, 3, =4=
+
+  _muscorum, Philoscia_, description of, 29
+
+
+  Names, local, 15
+
+  _nasatum, Armadillidium_, description of, 40
+
+  Nephrocytes, branchial, 8
+
+        "      cephalic, 8
+
+  Nerve cord, 8, =8=
+
+  Nervous system, 8
+
+  Norman, Rev. Canon A. M., 25, 27, 45
+
+
+  _oceanica, Ligia_, description of, 20
+
+  Oenigen, Miocene of, 2
+
+  Old-sows, 16
+
+  Old women of the wood, little, 16
+
+  Oligocene, 2
+
+  Onisci, 17
+
+     "    characters of, 27
+
+  Oniscidae, 19
+
+  _Oniscus_, 28
+
+      "      branchial nephrocytes, 8
+
+      "      characters of, 17, 18, 27
+
+      "      _agilis_, 21
+
+      "      _asellus_, 4, 15, 28, 44, Plate ix.
+
+  _Oniscus asellus_, Albino in Epping Forest, 28
+
+       "       "     description of, 27
+
+       "       "     excretory organs of, 8
+
+       "       "     flagellum of, =28=
+
+       "       "     young examples of, 28
+
+       "   _convexus_, 39
+
+       "   _fossor_, 19, 28
+
+       "   _granulatus_, 32
+
+       "   _murarius_, 27
+
+       "   _muscorum_, 29
+
+       "   _oceanicus_, 20
+
+       "   _pulchellum_, 42
+
+       "   _sylvestris_, 29
+
+  Oolite, 2
+
+  Ovaries, 8, =8=
+
+  Oviducts, 8, =8=
+
+
+  Palmer, 16
+
+  Penis, 9, =9=
+
+  Peduncle, 3, =3=
+
+  _Philoscia_, 21, 28
+
+       "       characters of, 17, 18, 29
+
+       "       _couchii_, 44, Plate xi.
+
+       "           "     description of, 30
+
+       "           "     flagellum of, =30=
+
+       "       _marmorata_, 29
+
+       "       _muscorum_, 21, 44, Plate x.
+
+       "            "      description of, 20
+
+       "            "      flagellum of, =29=
+
+  _Philougria celer_, 29
+
+       "        _riparia_, 22
+
+       "        _rosea_, 24
+
+       "        _vivida_, 23
+
+  Physicians, college of, rules for preparing woodlice for
+       medicinal use, 18
+
+  _pictus, Porcellio_, description of, 33
+
+  Pill millipede, 15, 40
+
+  _Platyarthrus_, 22
+
+        "         characters of, 17, 18, 39
+
+        "         _hoffmannseggii_, 44, Plate xii.
+
+        "               "          description of, 30
+
+        "               "          flagellum of, =31=
+
+  _Porcellio_, 6, 28, 38
+
+        "      characters of, 7, 18, 32
+
+        "      _armadilloides_, 39
+
+        "      _asper_, 32
+
+        "      _aztecus_, 35
+
+        "      _brandtii_, 32
+
+        "      _cinerascens_, 35
+
+        "      _cingendus_, 38
+
+        "      _cotillae_, 35
+
+        "      _cubensis_, 35
+
+        "      _degeerii_, 35
+
+        "      _dilatatus_, 34, 44, Plate xv.
+
+        "           "       description of, 33
+
+        "           "       flagellum of, =34=
+
+        "       _dubius_, 32, 33
+
+        "       _ferrugineus_, 34
+
+        "       _flavipes_, 35
+
+        "       _flavo-vittatus_, 37
+
+        "       _frontalis_, 37
+
+        "       _graniger_, 32
+
+        "       _laevis_, 39, 44, Plate xvii.
+
+        "           "     description of, 35
+
+        "           "     flagellum of, =35=
+
+        "       _lugubris_, 36
+
+        "       _maculicornis_, 37
+
+        "       _melanocephalus_, 33
+
+        "       _mexicanus_, 35
+
+        "       _mixtus_, 33
+
+        "       _montezumae_, 32
+
+        "       _musculus_, 35
+
+        "       _nemorensis_, 36
+
+        "       _nigra_, 32
+
+        "       _paulensis_, 32
+
+        "       _pictus_, 34, 44, Plate xiv.
+
+        "       description of, 33
+
+        "       flagellum of, =33=
+
+        "       _poeyi_, 35
+
+        "       _pruinosus_, 37
+
+        "       _quercum_, 36
+
+        "       _rathkei_, 35, 36, 44, 45
+
+        "           "      description of, 34, Plate xvi.
+
+        "           "      flagellum of, =35=
+
+        "       _ratzeburgii_, 44, Plate xviii.
+
+        "            "         description of, 36
+
+        "            "         flagellum of, =36=
+
+        "       _scaber_, 28, 44, Plate xiii.
+
+        "           "     description of, 32
+
+        "       _scaber_, development of, 9
+
+        "           "     flagellum of, 32
+
+        "           "     Milne Edwards, 33
+
+        "       _spinifrons_, 39
+
+        "       _striatus_, 34
+
+        "       _sumichtasti_, 35
+
+        "       _syriacus_, 35
+
+        "       _tetramoerus_, 34
+
+        "       _trilineatus_, 34
+
+        "       _trivittatus_, 34
+
+        "       _truncatus_, 37
+
+        "       _urbicus_, 35
+
+  _Porcellionides_, Miers, 37
+
+  Preservation of Woodlice, methods of, 16
+
+  Pro-ectoderm, 10, inset facing =10=
+
+  Pro-endoderm, 10, inset facing =10=
+
+  Protoplasm, formative, 10
+
+  _pruinosus, Metoponorthus_, description of, 37
+
+  pseudotracheae, 31
+
+  _pulchellum, Armadillidium_, description of, 42
+
+  _pusillus, Trichoniscus_, description of, 22
+
+  Purbeck Beds, 2
+
+
+  Quay-louse, 20
+
+  Quay lowders, 20
+
+
+  _rathkei, Porcellio_, description of, 34
+
+  _ratzeburgii, Porcellio_, description of, 36
+
+  Reproductive organs, 8, =8=, =9=
+
+  _roseus, Trichoniscus_, description of, 24
+
+  Roule, Professor Louis, 9
+
+
+  Sandstone, old red, 1
+
+  Sars, Professor G. O., 17, 23
+
+  _scaber, Porcellio_, description of, 32
+
+  Scharff, Dr. R. F., 17, 19, 23, 45
+
+  Seminal reservoir, 9, =9=
+
+  Socchetre, 16
+
+  Sow bug, 15
+
+  Species, distribution of, 43
+
+  St. Anthony's hogs, 16
+
+  Stebbing, the Rev. T. R. R., 19, 21, 35, 44, 45
+
+  Swanley Horticultural College, 14
+
+
+  Tertiary deposits, 2
+
+  Testes, 9, =9=
+
+  Thorax, 2, 3
+
+  Thrush louse, 15
+
+  Tiggyhog, 15
+
+  Tracheae, 6, 31
+
+  Trichoniscidæ, characters of, 18, 22
+
+  _Trichoniscoides_, 21, 22, 26
+
+       "             characters of, 17, 18, 25
+
+       "             _albidus_, 44, 45
+
+       "              "    description of, 25
+
+       "              "    flagellum of, =25=
+
+  _Trichoniscus_, 21, 22, 26
+
+       "          characters of, 17, 18, 22
+
+       "          _pusillus_, 22, 23, 24, 25, 44, Plate iii.
+
+       "               "      description of, 22
+
+       "               "      flagellum of, =23=
+
+       "           _pygmaeus_, description of, 23
+
+       "           _roseus_, 23, 25, 44, Plate v.
+
+       "               "     description of, 24
+
+       "               "     flagellum of, =24=
+
+       "           _vividus_, 22, 25, 44, Plate iv.
+
+       "                "     description of, 23
+
+       "                "     flagellum of, =24=
+
+  Tubes for specimens, 16
+
+  _Typhloniscus steinii_, 30
+
+
+  _vividus, Trichoniscus_, description of, 23
+
+  _vulgare, Armadillidium_, description of, 41
+
+
+  Walking legs, 4, 5
+
+  Webb, Mr. Wilfred Mark, 20, 25, 26, 35, 36, 45
+
+  Welsh names for Woodlice, 16
+
+  Westwood, Bate and, 17, 19, 30
+
+  White arsenic for destroying Woodlice, 14
+
+  Willmott, Miss, 45
+
+  Wood-ants, 15
+
+  Woodlice, in captivity, 12
+
+      "     methods for getting rid of, 24
+
+      "     position of, 1
+
+      "     storage of specimens, 16
+
+      "     Welsh names for, 16
+
+  Woodlouse, common, 4
+
+
+  Yolk, food, 10, 11, inset facing =10=
+
+
+  _Zia agilis_, 21
+
+     "     _melanocephala_, 29
+$
+
+
+
+
+LIST OF PLATES.
+
+
+                                                  PLATE
+
+  _Ligia oceanica_ Linné                             I.
+
+  _Ligidium hypnorum_ Cuvier                        II.
+
+  _Trichoniscus pusillus_ Brandt                   III.
+
+  _Trichoniscus vividus_ Koch                       IV.
+
+  _Trichoniscus roseus_ Koch                         V.
+
+  _Trichoniscoides albidus_ Budde-Lund              VI.
+
+  _Haplophthalmus mengii_ Zaddach                  VII.
+
+  _Haplophthalmus danicus_ Budde-Lund             VIII.
+
+  _Oniscus asellus_ Linné                           IX.
+
+  _Philoscia muscorum_ Scopoli                       X.
+
+  _Philoscia couchii_ Kinahan                       XI.
+
+  _Platyarthrus hoffmannseggii_ Brandt             XII.
+
+  _Porcellio scabier_ Latreille                   XIII.
+
+  _Porcellio pictus_ Brandt and Ratzeburg          XIV.
+
+  _Porcellio dilatatus_ Brandt                      XV.
+
+  _Porcellio rathkei_ Brandt                       XVI.
+
+  _Porcellio laevis_ Latreille                    XVII.
+
+  _Porcellio ratzeburgii_ Brandt                 XVIII.
+
+  _Metoponorthus pruinosus_ Brandt                 XIX.
+
+  _Metoponorthus cingendus_ Kinahan                 XX.
+
+  _Cylisticus convexus_ De Geer                    XXI.
+
+  _Armadillidium nasatum_ Budde-Lund              XXII.
+
+  _Armadillidium vulgare_ Latreille              XXIII.
+
+  _Armadillidium pulchellum_ Zencker              XXIV.
+
+  _Armadillidium depressum_ Brandt                 XXV.
+
+[Illustration: _PLATE I._
+
+LIGIA OCEANICA Linné. THE QUAY-LOUSE.
+
+_Length, two to three centimetres._
+
+Charles Sillem, del. ad nat. F. W. Reader, sculpt.]
+
+[Illustration: _PLATE II._
+
+LIGIDIUM HYPNORUM Cuvier.
+
+_Length, nine millimetres._
+
+Charles Sillem, del. ad nat. F. W. Reader, sculpt.]
+
+[Illustration: _PLATE III._
+
+TRICHONISCUS PUSILLUS Brandt.
+
+_Length, four millimetres._
+
+Charles Sillem, del. ad nat. F. W. Reader, sculpt.]
+
+[Illustration: _PLATE IV._
+
+TRICHONISCUS VIVIDUS Koch.
+
+_Length, eight millimetres._
+
+Charles Sillem, del. ad nat. F. W. Reader, sculpt.]
+
+[Illustration: _PLATE V._
+
+TRICHONISCUS ROSEUS Koch.
+
+_Length, five millimetres._
+
+Charles Sillem, del. ad nat. F. W. Reader, sculpt.]
+
+[Illustration: _PLATE VI._
+
+TRICHONISCOIDES ALBIDUS Budde-Lund.
+
+_Length, four millimetres._
+
+Charles Sillem, del. ad nat. F. W. Reader, sculpt.]
+
+[Illustration: _PLATE VII._
+
+HAPLOPHTHALMUS MENGII Zaddach.
+
+_Length, three to four millimetres._
+
+Charles Sillem, del. ad nat. F. W. Reader, sculpt.]
+
+[Illustration: _PLATE VIII._
+
+HAPLOPHTHALMUS DANICUS Budde-Lund.
+
+_Length, three to four millimetres._
+
+Charles Sillem, del. ad nat. F. W. Reader, sculpt.]
+
+[Illustration: _PLATE IX._
+
+ONISCUS ASELLUS Linné (The common slater).
+
+_Length, sixteen millimetres._
+
+Charles Sillem, del. ad nat. F. W. Reader, sculpt.]
+
+[Illustration: _PLATE X._
+
+PHILOSCIA MUSCORUM Scopoli.
+
+_Length, nine millimetres._
+
+Charles Sillem, del. ad nat. F. W. Reader, sculpt.]
+
+[Illustration: _PLATE XI._
+
+PHILOSCIA COUCHII Kinahan.
+
+_Length, nine millimetres._
+
+Charles Sillem, del. ad nat. F. W. Reader, sculpt.]
+
+[Illustration: _PLATE XII._
+
+PLATYARTHRUS HOFFMANNSEGGII Brandt.
+
+_Length, three millimetres._
+
+Charles Sillem, del. ad nat. F. W. Reader, sculpt.]
+
+[Illustration: _PLATE XIII._
+
+PORCELLIO SCABER Latreille.
+
+_Length, fourteen millimetres._
+
+Charles Sillem, del. ad nat. F. W. Reader, sculpt.]
+
+[Illustration: _PLATE XIV._
+
+PORCELLIO PICTUS Brandt and Ratzeburg.
+
+_Length, thirteen millimetres._
+
+Charles Sillem, del. ad nat. F. W. Reader, sculpt.]
+
+[Illustration: _PLATE XV._
+
+PORCELLIO DILATATUS Brandt.
+
+_Length, fifteen millimetres._
+
+Charles Sillem, del. ad nat. F. W. Reader, sculpt.]
+
+[Illustration: _PLATE XVI._
+
+PORCELLIO RATHKEI Brandt.
+
+_Length, twelve millimetres._
+
+Charles Sillem, del. ad nat. F. W. Reader, sculpt.]
+
+[Illustration: _PLATE XVII._
+
+PORCELLIO LAEVIS Latreille.
+
+_Length, sixteen millimetres._
+
+Charles Sillem, del. ad nat. F. W. Reader, sculpt.]
+
+[Illustration: _PLATE XVIII._
+
+PORCELLIO RATZEBURGII Brandt.
+
+_Length, eleven millimetres._
+
+Charles Sillem, del. ad nat. F. W. Reader, sculpt.]
+
+[Illustration: _PLATE XIX._
+
+METOPONORTHUS PRUINOSUS Brandt.
+
+_Length, nine millimetres._
+
+Charles Sillem, del. ad nat. F. W. Reader, sculpt.]
+
+[Illustration: _PLATE XX._
+
+METOPONORTHUS CINGENDUS Kinahan.
+
+_Length, six millimetres._
+
+Charles Sillem, del. ad nat. F. W. Reader, sculpt.]
+
+[Illustration: _PLATE XXI._
+
+CYLISTICUS CONVEXUS De Geer.
+
+_Length, twelve millimetres._
+
+Charles Sillem, del. ad nat. F. W. Reader, sculpt.]
+
+[Illustration: _PLATE XXII._
+
+ARMADILLIDIUM NASATUM Budde-Lund.
+
+_Length, fifteen millimetres._
+
+Charles Sillem, del. ad nat. F. W. Reader, sculpt.]
+
+[Illustration: _PLATE XXIII._
+
+ARMADILLIDIUM VULGARE Latreille.
+
+_Length, fifteen millimetres._
+
+Charles Sillem, del. ad nat. F. W. Reader, sculpt.]
+
+[Illustration: _PLATE XXIV._
+
+ARMADILLIDIUM PULCHELLUM Zencker.
+
+_Length, five millimetres._
+
+Charles Sillem, del. ad nat. F. W. Reader, sculpt.]
+
+[Illustration: _PLATE XXV._
+
+ARMADILLIDIUM DEPRESSUM Brandt.
+
+_Length, fifteen millimetres._
+
+Charles Sillem, del. ad nat. F. W. Reader, sculpt.]
+
+
+       *       *       *       *       *
+
+
+Transcriber's Notes
+
+Obvious typographical errors have been corrected. Inconsistent
+accents, punctuation, and hyphenation are as in the original text.
+
+The "æ" ligature is used interchangeably with "ae" throughout.
+
+Some taxonomic names may have changed since 1906.
+
+The following misprints and misspellings have been noted or corrected:
+
+CONTENTS:-
+Page  vii: "Family--Ligidæ " changed to "Family--Ligiidæ".
+Page  vii: "Haplopthalmus mengii" changed to "Haplophthalmus mengii".
+Page viii: "Armydillidium vulgare" changed to "Armadillidium vulgare".
+
+MAIN PART OF BOOK:-
+Page  2: "Aegidae is found" changed to "Aegidae which is found".
+Page 16: "naptha" changed to "naphtha" in footnote.
+Page 28: "Thornsharn" changed to "Thorsharn".
+Page 29: "Philoscia marmorala" changed to "Philoscia marmorata".
+At the end of the following lines, there is a missing page reference:
+  Page 30: "1868  _Philoscia couchii_ Bate and Westwood (1), p."
+  Page 33: "1868  _Porcellio pictus_ Bate and Westwood (1), p."
+  Page 33: "1868  _Porcellio dilatatus_ Bate and Westwood (1), p."
+
+INDEX:-
+Page 51: "Ligidae, characters of" changed to "Ligiidae, characters of".
+
+
+
+
+
+End of the Project Gutenberg EBook of The British Woodlice, by 
+Wilfred Mark Webb and Charles Sillem
+
+*** END OF THE PROJECT GUTENBERG EBOOK 43928 ***