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diff --git a/43946.txt b/43946.txt deleted file mode 100644 index eb30893..0000000 --- a/43946.txt +++ /dev/null @@ -1,24586 +0,0 @@ -Project Gutenberg's The Sea-beach at Ebb-tide, by Augusta Foote Arnold - -This eBook is for the use of anyone anywhere at no cost and with -almost no restrictions whatsoever. You may copy it, give it away or -re-use it under the terms of the Project Gutenberg License included -with this eBook or online at www.gutenberg.org/license - - -Title: The Sea-beach at Ebb-tide - A Guide to the Study of the Seaweeds and the Lower Animal - Life Found Between Tide-marks - -Author: Augusta Foote Arnold - -Release Date: October 13, 2013 [EBook #43946] - -Language: English - -Character set encoding: ASCII - -*** START OF THIS PROJECT GUTENBERG EBOOK THE SEA-BEACH AT EBB-TIDE *** - - - - -Produced by Chris Curnow, RichardW and the Online -Distributed Proofreading Team at http://www.pgdp.net (This -file was produced from images generously made available -by The Internet Archive) - - - - - - - THE - SEA-BEACH AT EBB-TIDE - - - - - THE - - SEA-BEACH AT EBB-TIDE - - A GUIDE TO THE STUDY OF - THE SEAWEEDS AND THE - LOWER ANIMAL LIFE FOUND - BETWEEN TIDE-MARKS - - BY - AUGUSTA FOOTE ARNOLD - - WITH MORE THAN - 600 ILLUSTRATIONS - - [Illustration] - - NEW YORK - THE CENTURY CO. - 1901 - - And hath been tutor'd in the rudiments - Of many desperate studies. - - SHAKSPERE. - - - Copyright, 1901, by - THE CENTURY CO. - - /Published May, 1901/ - - - THE DE VINNE PRESS. - - - - -PREFACE - - -This volume is designed to be an aid to the amateur collector and -student of the organisms, both animal and vegetable, which are found -upon North American beaches. In it are described many invertebrates -and some of the more notable varieties of seaweeds, and each -individual is given its proper place in the latest classification. - -The technicality of classification or scientific grouping may at -first seem repellent, but it in reality makes the study of these -objects more simple; and a systematic arrangement has been adopted in -the belief that it is the easiest as well as the only satisfactory -way of becoming familiar with the organisms described. Without it -a very confused picture of separate individuals would be presented -to the mind, and a book like the present one would become a mere -collection of isolated scraps of information. Morphology, or the -study of structure, has been touched upon just enough to show the -objects from the biologist's point of view and to enable the observer -to go a little beyond the bare learning of names. - -Scientific names have been used from necessity, for the plants -and animals of the beach are so infrequently observed, except by -scientific people, that but few of them have common names; and, as -a matter of fact, the reader will find that a scientific name is -as easily remembered as a common one. Technical phraseology has, -however, been avoided as much as possible, even at the expense of -conciseness and precision; where it has been used, care has been -taken to explain the terms so that their meaning will be plain to -every one. A general glossary has been omitted, but the technical -terms used have been indexed. The illustrations will bear the use of -a hand-glass, and this will often bring out details which cannot well -be seen by the unaided eye. - -The systematic table of the marine algae, as given in Part I, and -followed in the text, will be of use to collectors who wish to make -herbaria. In order to name and group specimens such a guide is -necessary. Should specific names lead to embarrassment, many of them -can be neglected, for the names of genera are often a sufficient -distinction. - -Since so many species of invertebrates are found on the beach that -a complete enumeration of them is impracticable, only the most -conspicuous ones have been selected for description in Part II; -but the attempt has been made to designate the various classes and -orders with sufficient clearness to enable the collector to identify -the objects commonly found on the shore, and to follow the subject -further, if he so desires, in technical books. - -It is hoped that this book will suggest a new interest and pleasure -to many, that it will encourage the pastime of collecting and -classifying, and that it will serve as a practical guide to a -better acquaintance with this branch of natural history, without -necessitating serious study. Marine organisms are interesting -acquaintances when once introduced, and the real purpose of the -author is to present, to the latent naturalist, friends whom he will -enjoy. - -Grateful acknowledgment is here made to the following persons who -have kindly assisted and advised the author and have also extended -valued courtesies to her in the preparation of this book: Smith Ely -Jelliffe, M.D., Ph.D.; Herbert M. Richards, A.B., Ph.D., Professor -of Botany in Barnard College; Marshall A. Howe, A.B., Ph.D.; the -Rev. George A. Holst; the Long Island Historical Society of Brooklyn -for the use of its fine herbarium, containing the collections of -Mr. John Hooper, Mr. A. R. Young, and others, from which most of -the illustrations of algae in this book were photographed; Miss -Toedtleberg, Librarian of the Long Island Historical Society; Miss -Ingalls, in charge of the Museum of the Long Island Historical -Society; Dr. Theodore Gill; James A. Benedict, Ph.D., Assistant -Curator of Marine Invertebrates in the Smithsonian Institution; Miss -Mary J. Rathbun, second Assistant Curator of Marine Invertebrates in -the Smithsonian Institution; Miss Harriet Richardson; and especially -to Mr. John B. Henderson, Jr. - - * * * * * - -Thanks, also, are due to Messrs. Macmillan & Co. for permission to -use cuts from the "Cambridge Natural History," Parker and Haswell's -"Zooelogy", and Murray's "Introduction to the Study of Seaweeds"; -to Swan Sonnenschein & Co. for the use of cuts from Sedgwick's -"Student's Text-book of Zooelogy"; to Wilhelm Engelmann for a cut from -"Die natuerlichen Pflanzenfamilien" of Engler and Prantl; to Little, -Brown & Co. for permission to reproduce illustrations from Agassiz's -"Contributions to the Natural History of the United States"; to Henry -Holt & Co. for a cut from McMurrich's "Invertebrate Morphology"; -to Houghton, Mifflin & Co. for cuts from the "Riverside Natural -History" and Agassiz's "Seaside Studies in Natural History"; to the -Commonwealth of Massachusetts for the use of illustrations from -Verrill's "Report upon the Invertebrate Animals of Vineyard Sound -and the Adjacent Waters," Gould's "Invertebrata of Massachusetts" -(ed. Binney), and certain fisheries reports; and to the United -States government for illustrations taken from Bulletin 37 of the -Smithsonian Institution and from reports of the United States Fish -Commission. - - - - -CONTENTS - - - INTRODUCTION - - PAGE - - I Signs on the Beach 1 - - II Collecting 6 - - III Classification 19 - - IV Animal Life in its Lowest Forms 21 - - V Distribution of Animal Life in the Sea 23 - - VI Some Botanical Facts about Algae 25 - - VII Naming of Plants 28 - - VIII Distribution of Algae 30 - - IX Some Peculiar and Interesting Varieties of Algae 32 - - X Uses of Algae 37 - - XI Collecting at Bar Harbor 40 - - PART I - - MARINE ALGAE - - I BLUE-GREEN SEAWEEDS 47 - (CYANOPHYCEAE) - - GRASS-GREEN SEAWEEDS 47 - (CHLOROPHYCEAE) - - II OLIVE-GREEN AND BROWN SEAWEEDS 61 - (PHAEOPHYCEAE) - - III RED SEAWEEDS 75 - (RHODOPHYCEAE OR FLORIDEAE) - - PART II - - MARINE INVERTEBRATES - - I PORIFERA (SPONGES) 99 - - II C[OE]LENTERATA (POLYPS) 111 - - III WORMS 159 - (PLATYHELMINTHES, NEMATHELMINTHES, ANNULATA) - - IV MOLLUSCOIDA 187 - - V ECHINODERMATA 199 - - VI ARTHROPODA 237 - - VII MOLLUSCA 299 - - VIII CHORDATA 471 - - INDEX 479 - - - - -INTRODUCTION - - - In vain through every changeful year - Did nature lead him as before; - A primrose by a river's brim, - A yellow primrose was to him, - And it was nothing more. - - At noon, when by the forest's edge - He lay beneath the branches high, - The soft blue sky did never melt - Into his heart; he never felt - The witchery of the soft blue sky. - - WORDSWORTH. - - - To him who in the love of Nature holds - Communion with her visible forms, she speaks - A various language. - - BRYANT. - - - - -INTRODUCTION - - - - -I - -SIGNS ON THE BEACH - - -The sea-shore, with its stretches of sandy beach and rocks, seems, -at first sight, nothing but a barren and uninteresting waste, merely -the natural barrier of the ocean. But to the observant eye these -apparently desolate reaches are not only teeming with life; they are -also replete with suggestions of the past. They are the pages of a -history full of fascination for one who has learned to read it. - -In this history even the grains of sand have a part. Though so humble -now, they once formed the rocky barriers of the shore. They stood -as do the rocks of to-day, defiant and seemingly everlasting, but -the fury of the sea, which knows no invincible adversary, has laid -them low. Every coast-line shows the destructive effects of the sea, -for the bays and coves, the caves at the bases of the cliffs, the -buttresses, stocks, needles, and skerries, are the work of the waves. -And this work is constantly going on. - - Even a blind man could not stand long upon a shingly beach without - knowing that the sea was busily at work. Every wave that rolls - in from the open ocean hurls the pebbles up the slope of the - beach, and then as soon as the wave has broken and the water has - dispersed, these pebbles come rattling down with the currents that - sweep back to the sea. The clatter of the beach thus tells us - plainly that as the stones are being dragged up and down they are - constantly knocked against each other; and it is evident that by - such rough usage all [pg002] angular fragments of rock will soon - have their corners rounded off and become rubbed into the form of - pebbles. As these pebbles are rolled to and fro upon the beach they - get worn smaller and smaller, until at length they are reduced - to the state of sand. Although this sand is at first coarse, it - gradually becomes finer and finer as surely as though it were - ground in a mill; and ultimately it is carried out to sea as fine - sediment and laid down upon the ocean floor.[1] - -[Footnote 1: Huxley.] - -The story of the sands is not only one of the conflict of the sea -and rocks; it is also a story of the winds. It is the winds that -have rescued them from the waves and driven them about, sifting -and assorting them, arranging them in graceful forms, and often -heaping them up into dunes which, until fastened by vegetation, are -themselves ever moved onward by the same force, sometimes burying -fertile lands, trees, and even houses in their march. The sands, -moreover, are in turn themselves destructive agents, to whose power -the many fragments which strew the beach and dunes bear ample -witness. The knotty sticks so commonly seen on the beach are often -the hearts of oak- or cedar-trees from which the tiny crystals of -sand have slowly cut away their less solid outer growth. Everything, -in fact, upon the sands is "beach-worn," even to the window-glass of -life-saving stations, which is frequently so ground that it loses its -transparency in a single storm. - -The beach is also a vast sarcophagus holding myriads of the dead. -"If ghosts be ever laid, here lie ghosts of creatures innumerable, -vexing the mind in the attempt to conceive them." And there are -certain sands which may be said to sing their requiem, the so-called -musical sands, like the "Singing Beach" at Manchester-by-the-Sea, -which emit sounds when struck or otherwise disturbed. On some -beaches these sounds resemble rumbling, on others hooting; sometimes -they are bell-like and even rhythmical. The cause of this sonorous -character is not definitely known, but it is possibly due to films -of compressed gases which separate each grain as with a cushion, and -the breaking of which [pg003] causes, in the aggregate, considerable -vibrations. Such sands are not uncommon, having been recorded in -many places, and they exist probably in many others where they have -escaped observation. They may be looked for above the water-line, -where the sand is dry and clean. - -We have to do, however, in this volume, not with the history of the -past, nor with the action of physical forces, but with the life of -the present, and to find this, in its abundance, one must go down -near the margin of the water, where the sands are wet. There is no -solitude here; the place is teeming with living things. As each wave -retreats, little bubbles of air are plentiful in its wake. Underneath -the sand, where each bubble rose, lives some creature, usually a -mollusk, perhaps the razor-shell /Solen ensis/. By the jet of water -which spurts out of the sand, the common clam /Mya arenaria/ reveals -the secret of its abiding-place. A curious groove or furrow here and -there leads to a spot where /Polynices heros/ has gone below; and the -many shells scattered about, pierced with circular holes, tell how -/Polynices/ and /Nassa/ made their breakfast and their dinner. Only -the lifting of a shovelful of sand at the water's edge is needed to -disclose the populous community of mollusks, worms, and crustaceans -living at our feet, just out of sight. - -Even the tracks and traces of these little beings are full of -information. What may be read in the track of a bird on the sand is -thus described by a noted ornithologist: - - Here are foot-notes again, this time of real steps from real - feet. . . . The imprints are in two parallel lines, an inch or so - apart; each impression is two or three inches in advance of the - next one behind; none of them are in pairs, but each one of one - line is opposite the middle of the interval between two of the - other line; they are steps as regular as a man's, only so small. - Each mark is fan-shaped; it consists of three little lines less - than an inch long, spreading apart at one extremity, joined at - the other. At the joined end, and also just in front of it, a - flat depression of the sand is barely visible. Now following the - track, we see it run straight a yard or [pg004] more, then twist - into a confused ball, then shoot out straight again, then stop, - with a pair of the footprints opposite each other, different from - the other end of the track, that began as two or three little - indistinct pits or scratches, not forming perfect impressions of a - foot. Where the track twisted there are several little round holes - in the sand. The whole track commenced and finished upon the open - sand. The creature that made it could not, then, have come out - of either the sand or the water; it must have come down from the - air--a two-legged flying thing, a bird. To determine this, and, - next, what kind of bird it was, every one of the trivial points of - the description just given must be taken into account. It is a bit - of autobiography, the story of an invitation to dine, acceptance, - a repast, an alarm at the table, a hasty retreat. A bird came on - wing, lowering till the tips of its toes just touched the sand, - gliding half on wing, half afoot, until the impetus of flight was - exhausted; then folding its wings, but not pausing, for already a - quick eye spied something inviting; a hasty pecking and probing to - this side and that, where we found the lines entangled; a short run - after more food; then a suspicious object attracted its attention; - it stood stock-still (just where the marks were in a pair), till, - thoroughly alarmed, it sprang on wing and was off.[2] - -[Footnote 2: Elliott Coues.] - -Following the key further, he draws more conclusions. The tracks are -not in pairs, so the bird does not belong to the perchers; therefore -it must be a wader or a swimmer. There are no web-marks to indicate -the latter; hence it is a three-toed walking or wading bird. It had -flat, long, narrow, and pointed wings because it came gliding swiftly -and low, and scraped the sand before its wings were closed. This -is shown by the few scratches before the prints became perfect. A -certain class of birds thus arrests the impetus of flight. It had a -long feeling-bill, as shown by the little holes in the sands where -the marks became entangled; and so on. These combined characteristics -belong to one class of birds and to no other; so he knows as -definitely as [pg005] though he had seen the bird that a sandpiper -alighted here for a brief period, for here is his signature. - -It is plain that tracks in the sand mean as much to the naturalist as -do tracks in the snow to the hunter, and trails on the land to the -Indian who follows his course by signs not seen by an untrained eye. - -The tide effaces much that is written by foot and wing, but sometimes -such signs are preserved and become veritable "footprints on the -sands of time." In the Museum of Natural History in New York is -a fossil slab, taken from the Triassic sandstone, showing the -footprints of a dinosaurian reptile now extinct, which, in that long -ago, walked across a beach--an event unimportant enough in itself, -but more marvelous than any tale of imagination when recorded for -future ages. From such tracks, together with fragments of skeletons, -the dinosaur has been made to live again, and its form and structure -have been as clearly defined as those of the little sandpiper of Dr. -Coues. - -[pg006] - - - - -II - -COLLECTING - - -It has been said that everything on the land has its counterpart -in the sea. But all land animals are separate and independent -individuals, while many of those of the sea are united into organic -associations comprising millions of individuals inseparably connected -and many of them interdependent, such as corals, hydroids, etc. These -curious communities can be compared only to the vegetation of the -land, which many of them resemble in outer form. Other stationary -animals, such as oysters and barnacles, which also depend upon -floating organisms for their food, have no parallel on the land. - -The water is crowded with creatures which prey upon one another, -and all are interestingly adapted to their mode of life. Shore -species are exceedingly abundant, and the struggle for life is there -carried on with unceasing strife. In the endeavor to escape pursuers -while they themselves pursue, these animals have various devices of -armature and weapons of defense; they have keen vision, rapid motion, -and are full of arts and wiles. One of the first resources for safety -in this conflict is that of concealment. This is effected not only -by actual hiding, but very generally by mimicry in simulating the -color of their surroundings, and often by assuming other forms. Thus, -for instance, the sea-anemone when expanded looks like a flower and -is full of color, but when it contracts becomes so inconspicuous as -to be with difficulty distinguished from the rock to which it is -attached. Anemones also have stinging threads (nematophores), which -they dart out for further defense. [pg007] - -The study of biology has great fascination, and the subject seldom -fails to awaken interest as soon as the habit of observation is -formed. Jellyfishes, hardly more dense than the water and almost as -limpid, swimming about with graceful motion, often illuminating the -water at night with their phosphorescence, showing sensitiveness, -volition, and order in their lives, cannot fail to excite wonder -in even the most careless observer. Not less interesting are the -thousands of other animals which crowd the shores, lying just beneath -the surface of the sand, filling crevices in the rocks, hiding under -every projection, or boldly--perhaps timidly, who shall say?--lying -in full view, yet so inconspicuous that they are easily passed by -unnoticed. - -To find these creatures, to study their habits and organization, to -consider the wonderful order of nature, leads through delightful -paths into the realms of science. But even without scientific study -the simple observation of the curious objects which lie at one's feet -as one walks along the beach is a delightful pastime. - -The features which separate the classes and the orders of both the -plant and the animal life are so distinctive that it requires but -very superficial observation to know them. It is easy to discriminate -between mollusks, echinoderms, and polyps, and to recognize the -relationship between univalves and bivalves, sea-urchins and -starfishes, sea-anemones and corals. The equally plain distinctions -between the branched, unbranched, tubular, and plate-like green algae -make them as easy to separate. - -The pleasure of a walk through field or forest is enhanced by knowing -something of the trees and flowers, and in the same way a visit to -the sea-shore becomes doubly interesting when one has some knowledge, -even though it be a very superficial one, of the organisms which -inhabit the shore. - - -ROCKY SHORES - -Rocky shores furnish an abundance and great variety of objects to the -collector. The seaweeds here find places of attachment, and the lee -and crevices of the rocks afford shelter to many animals which could -not live in more open and exposed places. The [pg008] rock pools -harbor species whose habitat is below low-water mark and which could -not otherwise bear the alternation of the tides. - -The first objects on the rocky beach to attract attention are the -barnacles and rockweeds. They are conspicuous in their profusion, -the former incrusting the rocks with their white shells, and the -latter forming large beds of vegetation; yet both are likely to be -passed by with indifference because of their plentifulness. They are, -however, not only interesting in themselves, but associated with -them are many organisms which are easily overlooked. The littoral -zone is so crowded with life that there is a constant struggle for -existence,--even for standing-room, it may be said,--and no class -of animals has undisputed possession of any place. Therefore the -collector should carefully search any object he gathers for other -organisms which may be upon it, under it, or even in it, such as -parasites, commensals, and the organisms which hide under it or -attach themselves to it for support. Let the rockweed (/Fucus/) be -carefully examined. Among the things likely to be found attached to -its fronds are periwinkles (/Littorina litorea/), which simulate -the plant in color, some shells being striped for closer mimicry. -Sertularian hydroids also are there, zigzagging over the fronds or -forming tufts of delicate horny branches upon them. Small jelly-like -masses at the broad divisions of the fronds may be compound -ascidians. Calcareous spots here and there may be polyzoans of -exquisite form, while spread in incrusting sheets over considerable -spaces are other species of /Polyzoa/. Tiny flat shelly spirals -are the worm-cases of /Spirorbis/. A pocket-lens is essential to -enable one to appreciate the beauty of these minute forms. Under the -rockweeds are many kinds of crustaceans; perhaps there will also be -patches of the pink urn-like egg-capsules of /Purpura/ at the base of -the fucus. - -Various kinds of seaweed abound in the more sheltered parts of the -rocks, and among them will be found amphipods and isopods, many of -which are of species different from those of the sandy beaches. Here, -too, is the little /Caprella/, imitating the seaweed in form, and -swaying its lengthened body, which is attached to the plant only by -its hind legs. On the seaweeds, as well as in the tide-pool, may be -found beautiful hydroids, and on [pg009] them the curious little -sea-spiders (/Pycnogonidae/), animals which seem to be all legs. - -Mollusks, and other classes as well, differ in different latitudes. -On the rocks of the Northern shores /Littorina/ and /Purpura/ shells -are very abundant, the latter in various colors and beautifully -striped. Limpets are also plentiful, but are not as conspicuous, -since they have flat, disk-shaped shells. When their capture is -attempted, they must be taken unawares and pushed quickly aside, -else they take such a firm hold of the rock that it is difficult -to dislodge them. Near low-water mark under ledges will perhaps be -found chitons, which are easily recognized by their oval, jointed -shells. On the California coast in like localities will be found -the beautiful /Haliotis/, /Acmaea/, and chitons. Every stone that -is lifted will disclose numbers of little amphipods (/Gammarus/), -which will scuttle away on their sides to other shelter; worms will -suddenly disappear into the mud, and perhaps a crab, here and there, -having no alternative, will make a stand and fight for his liberty. -Flat against the stone and not easily perceived may be a chiton, a -planarian worm, or a nudibranch. And just below the water's edge are -sea-urchins and starfishes, which grow in numbers as the eye becomes -accustomed to the search. - -The rock pools are natural aquaria, more interesting by far than any -prepared by man. The possibilities of these little sea-gardens are -beyond enumeration. The longer one studies them the more one finds. -In them all classes of seaweeds and marine invertebrates may be found -and their habits watched. The great beauty of these pools gives them -an esthetic charm apart from the scientific interest they excite. -Perhaps one may find here a sponge, and removing it to a shallow -vessel of sea-water can watch the currents of water it creates. -Several sponges of the same species placed in contact will at the -end of two days be closely united. If the sponges are of different -species they will not coalesce. - -In the clefts and crannies of the rocks are various fine seaweeds, -often of the red varieties, sea-anemones, hydroids, polyzoans, -crustaceans, mollusks, and ascidians. Crabs will be snugly [pg010] -ensconced under projecting surfaces. Most species are more plentiful -at the lowest-water mark, and many are found only at this point and -below. - - -SANDY SHORES - -On sandy shores the greater part of the inhabitants live under the -surface. Many give evidence of their presence by the open mouths of -their burrows, and some distinctly point out these places by piles -of sand or mud in coils at the opening. Some tubicolous worms have -their tubes projecting above the surface. The tubes of /Diopatra/ -are hung with bits of shells, seaweeds, and other foreign matter. -Some mollusks announce themselves by spurting jets of water or -sending bubbles of air from the sand. The majority of the underground -species, however, give no sign of their presence on the surface, -and must be found by digging. Many of them go deep into the sand, -and in searching for worms the digger must be quick- and expert, -or he will lose entirely or cut in two many of the most beautiful -ones, which retreat quickly and to the extremity of their holes at -the least alarm. One can be a rambler on the sandy beach for a long -time without being aware of the many beautiful objects which inhabit -the subsurface of the sand. The curious crab /Hippa/ will disappear -so quickly into the sand that one is hardly sure he has really seen -it. The vast number of worms will surprise any one who searches for -them by their variety, their beautiful color, and their interesting -shapes. Here again a glass is requisite to appreciate the delicacy -and beauty of their locomotive organs, their branchiae, and so on. The -most common of the gasteropod mollusks on sandy shores are /Nassa -obsoleta/, /Nassa trivittata/, and /Polynices (Lunatia) heros/. The -last are detected by the little mounds of sand which they push before -them as they plow their way just below the surface. On more southern -beaches, /Fulgur/, /Strombus/, and /Pyrula/ are the common varieties. -/Olivella/, /Oliva/, and /Donax/, also inhabitants of sandy beaches, -will quickly disappear when uncovered by the waves, being rapid -burrowers. Most of the many dead shells on the beach will be found -to be pierced with a round hole, which is [pg011] drilled by the -file-like tongue, or lingual ribbon, of /Polynices/, /Urosalpinx/, -or /Nassa/, which thus reach the animal within and suck out its -substance. Another similar species is /Polynices/ (/Neverita/) -/duplicata/, which extends to the Gulf of Mexico, while /P. heros/ -is not commonly found below Hatteras. Crustaceans are abundant on -the sandy beach over its whole breadth. Some of the sand-crabs live -above tide-mark. Among these is the fleet-footed /Ocypoda/, which is -interesting to watch. Often they go in numbers to the water's edge -and throw up mounds, behind which they crouch like cats, watching -for whatever prey the tide may bring up. When unable to outrun a -pursuer they rush into the surf and remain there until the danger is -past. The wet sand is often thickly perforated with the burrows of -the sandhoppers (/Orchestia/). These often rise about the feet as do -grasshoppers in the fields. - -[Illustration: PLATE I. Egg-capsules of Purpura lapillus. Egg-case of -Polynices heros. Egg-capsules of Buccinum undatum. Egg-case of the -skate. Fulgur canaliculata (whelk) and egg-cases.] - -/Hippa talpoida/ is a remarkable crab, somewhat resembling an egg. -It is not likely to be seen unless searched for by digging at the -water's edge. It burrows so rapidly that one must be quick to catch -it after it is exposed by the shovel. In some places the tests of -"sand-dollars" are common. The living animal may be found buried just -below the surface at extreme low-water mark. - -The sea-wrack drifted in lines along the shore will repay careful -examination, for here will be found many things belonging to other -shores and deep water. It is often alive with sandhoppers, which -hop away while one searches for less common things. Often the most -delicate seaweeds, numerous small shells, worms, polyzoans, etc., -will be found there. - -The surface of the sand-beach is strewn with remains of many species, -usually beach-worn, but interesting nevertheless as examples of -species one would like to find in better condition, but good -specimens of which elude ordinary search or are unobtainable except -by dredging. - -Egg-cases form another class of objects which are often gathered with -no idea of their identity. Of these the most common are the long -strings of saucer-like capsules which contain the eggs of the mollusk -/Fulgur/, those having square edges being [pg012] the egg-cases of -/F. carica/, and those having sharp edges those of /F. canaliculata/. -Collar-like sandy rings contain the eggs of /Polynices/ (/Lunatia/), -which are cemented together in this shape. The boys of Cape Cod -call them "tommy-cod houses." Cylindrical piles of little capsules, -sometimes called "ears of corn," hold the eggs of /Chrysodomus/. The -irregular masses of small hemispherical capsules are those of the -common whelk (/Buccinum/). The so-called "Devil's pocket-books" are -the egg-cases of the skate. - - -MUDDY SHORES - -On muddy shores the eel-grass (/Zostera marina/) grows abundantly, -giving an appearance of submerged meadows. It is one of the very -few flowering plants which live in salt water. In summer its little -green blossoms may be seen in grooves on the leaf-like blades. Many -animals live on and among eel-grass. Found upon it is the delicate -gasteropod mollusk /Lacuna vincta/, and its eggs in little rings; the -iridescent /Margarita helicina/, and /Nassa/, with its bright-yellow -eggs in small gelatinous masses; also little worms (/Spirorbis/) in -tiny flat spiral shells, compound ascidians in jelly-like masses, -clusters of shelly or horny polyzoans, isopods, planarian worms, and -so on. Scallops (/Pecten/) will be found at the base of the plants, -and the common prawns are very numerous, swimming freely about. Mud -flats and shores are the homes of many mollusks, especially of /Nassa -obsoleta/,--which is the most abundant shell of any considerable size -from Cape Cod to the Gulf of Mexico,--and of vast numbers of the tiny -/Littorinella minuta/, which serve as food for fishes and aquatic -birds. Clams and worms of all varieties are also abundant. - -There are many varieties of mud-crabs, of which the most common -are the "fiddlers," which honeycomb the banks and the surface of -salt-marshes with their burrows. The common edible crab /Callinectes -hastatus/ is plentiful in bays and estuaries. The sluggish -spider-crabs hide beneath the surface of the mud and in decaying -weeds and eel-grass. Hermit-crabs are plentiful here as well as -elsewhere. /Panopeus/ is a sluggish crab found in shallow water and -in all sorts of hiding-places along the shore. It [pg013] may often -be found in dead shells, and, in the South, in holes in the banks. -This genus is represented by a number of species, some of which are -quite pretty. - - -WHARVES AND BRIDGES - -On the piles of wharves and bridges may often be found beautiful -tubularian hydroids in large tufts just below low-water mark, -branched hydroids looking like little shrubs, polyzoans, -sea-anemones, mollusks, and ascidians. The species peculiar to these -localities are the boring mollusk /Teredo navalis/, or ship-worm, the -boring isopod /Limnoria lignorum/, and the boring amphipod /Chelura -terebrans/, all of which penetrate the wood and are most destructive. - -The animals and plants of tropical beaches and coral reefs are -so various and abundant, so curious and beautiful, as to make -a description or even an enumeration of them in a brief space -difficult. The collector is bewildered and excited when he first -views the profusion of the wonderful forms there found. - -It is not generally known that a fine species of "stony coral" -is common from Cape Cod southward, growing in clear water as an -incrustation on rocks, and developing little spires as it advances in -age. This species, the /Astrangia danae/, is especially interesting, -since it will live in a dish of clear sea-water, and the polyps will -expand, showing a very close relationship to the sea-anemone. With -care in changing the water this coral will live for days, and may be -examined in its expanded condition with a lens of moderate power. - -The most favorable time for collecting on any beach is at the lowest -tide, many objects being then uncovered which do not appear higher up -on the beach. At the spring-tides, which occur twice a month, at the -period of the new and that of the full moon, the ebb is especially -low, and affords an opportunity to search for forms whose habitat is -below ordinary low-water mark. During storms deep-water forms are -often torn from their beds and cast upon the beach. Shore-collecting -at these times is often very interesting. [pg014] - - -EQUIPMENT FOR COLLECTING INVERTEBRATES - -The equipment for collecting upon sandy beaches is a shovel, a sieve, -and a net. Numerous trials should be made with the shovel from about -half-tide mark to as deep as one cares to wade, and the sand raised -should be carefully searched for shells, crustaceans, and worms. -By washing out the sand in the sieve the smallest specimens, which -might otherwise escape notice, may be secured. On a rocky beach a -strong knife and a net are sufficient. It is well to have a number -of homeopathic vials for small specimens, which will be injured -by contact with larger forms, and jars for holding the general -collection. - - -PRESERVING INVERTEBRATES - -To preserve specimens, they should first be placed in a weak solution -of alcohol, the strength of which should be increased gradually until -the animal is entirely free from water and is hardened throughout. -If the alcohol becomes colored and sediment falls to the bottom -of the jar, the animal is degenerating, and the alcohol should be -changed. Specimens for transportation can be packed by wrapping each -one in a bit of cheese-cloth and then placing them together in a -large receptacle. Care should be taken to keep the fragile specimens -separate. Sand-dollars possess a pigment which discolors and soon -vitiates alcohol, and consequently these should be separated from -the other forms and placed where the alcohol may be changed from -time to time as appears necessary. The homeopathic vials containing -small specimens may be put into the can without injury to the other -specimens. Special cans of various sizes, with handles and screw -covers, are made for naturalists. One of these cans is a convenient -receptacle for carrying the alcohol to the station and for receiving -the collection for transportation. Careful notes should be made on -the spot of the conditions under which the species are found. One is -likely to forget details if this is delayed until one reaches home. -Labels should be used, giving name when known, or a number when the -name is not known, [pg015] corresponding with the note-book. Names -written with lead-pencil on a slip of paper will not be defaced by or -injure the alcohol. Collections when arranged permanently should be -placed in glass jars, the species being kept separate. - - -COLLECTING AND PRESERVING SEAWEEDS - -To collect seaweeds one must search for them on rocks, in tide-pools, -in the sea-wrack upon the beach, on piles of wharves, on eel-grass, -and on the surface of incoming waves. It is well to follow the -receding tide and take advantage of its lowest ebb (especially of -that of the spring-tides, as mentioned above) to search the extreme -limit of the beach in the short time it is exposed. Many of the red -seaweeds are found there. - -The equipment for collecting consists of a basket, two small tin -pails, one small enough to be carried within the other, a staff -with an iron edge at one end and a small net at the other, and a -pocket-lens. Rockweeds (/Fucus/) or other coarse gelatinous seaweeds -should be put into the basket. The pails, half filled with sea-water, -will receive the other specimens, fine and delicate algae being put -into the smaller pail. It is well to have a second small receptacle -for /Callithamnion/ and /Griffithsia/, if one can be further -burdened. /Desmarestia/ should be kept apart, if possible, since it -discolors and decomposes other algae; it should also have the earliest -attention when the time comes for mounting, and salt water should -be used for floating it upon the mount, otherwise the beauty of the -specimen will be impaired. - -Besides its use as a support, the staff is needed to dislodge -specimens from the rocks, and the net to secure those that are -floating just out of reach. When possible, it is desirable to secure -the whole plant, including the holdfast, and to gather several -plants of the same species, since they vary with age and other -conditions, and it is also well to have duplicates for exchange. It -is particularly desirable to obtain plants which are in fruit. Each -specimen as it is taken should be rinsed in the sea-water to free it -from sand. - -Collections should be mounted as soon as convenient, and [pg016] -especial care in this respect should be taken with red algae, as they -decompose quickly. The requisites for mounting are blotters, pieces -of muslin, two or more smooth boards, weights, a basin, and several -shallow dishes containing water. Fresh water has a strong action on -the color and substance of seaweeds, and specimens should not be left -in it for any length of time. - -Lift a specimen from the general collection, and in a basin of deep -water carefully wash off all superfluous matter; then place it in -shallow water and spread it out, trimming it judiciously, so that -when mounted it will not be too thick and the characteristics be -hidden. Specimens are more interesting and their species more easily -determined when laid out rather thin, showing their branching and -fruit. After the specimen is thus prepared, place it in a second -shallow dish of water. It should now be perfectly clean. Float it out -into the desired position, spreading it well, letting some parts show -the details of the branching, and other parts the general natural -effect of the mass. Run under it a rather heavy sheet of white paper, -and lift it carefully from the water. If raised from the center, -it is easier to let the water subside evenly and gradually without -disarranging the parts. Some collectors find it better to float the -specimen in water deep enough to allow the left hand to be placed -under the sheet to raise it. Lay the sheet on a plate, and with a -needle or forceps rearrange any of the delicate parts which have -fallen together. A few drops of water placed on any portion will -usually be sufficient to enable one to separate the branchlets or -ultimate ramifications. A magnifying-glass will be useful in this -work. - -Cover a blotter with mounted specimens, spread over them a piece -of cotton cloth, and on this place another blotter, upon which lay -more mounted specimens and a cloth. Proceed in this way until all -the specimens are used. Lay the pile of blotters between boards, and -on them place the weights. The weights should not be very heavy. -Judgment must be used in assorting the specimens, those that are fine -being placed together. Those that are coarse and likely to indent -the blotters should be placed between separate boards. In this way a -flat surface and an even pressure will be obtained. The blotters and -cloths should be [pg017] changed twice each of the first two days, -then the cloths should be removed and the specimens left in press for -a week, the blotters being changed daily. Be sure that the specimens -are perfectly dry before placing them in the herbarium. Label each -specimen with the name and the date and place of collection. - -There are some seaweeds which cannot be treated in the above manner. -/Fucus/ if placed in fresh water soon becomes slimy. It is so full of -gelatine that it soon destroys blotters; therefore it is well to hang -it up for several hours and then place it between newspapers, which -should be frequently changed, and as the plant becomes pliable it -should be arranged in proper position. - -Those specimens which do not adhere to paper in drying should be -secured with gum. When it is impossible to mount specimens at the -time they are collected, they can be preserved by drying; afterward -they can be soaked and mounted in the usual manner. To dry the -plants, lay them separately upon boards without pressing out the -sea-water, and leave them in an airy, shaded place until thoroughly -dry; then pack them loosely into boxes and label, giving date and -locality. Blotters or driers can be obtained at botanical-supply -stores at thirty-five cents per quire. - - -HOW TO ARRANGE A HERBARIUM - -The standard herbarium-paper is sixteen by eleven and a half -inches. The sheets are single, white, smooth, and quite heavy. -These, together with folded sheets of yellow manila paper, called -genus-covers, are the only requisites. It is desirable to have also -a case of shelves protected by glass doors. The shelves should be -twelve by eighteen inches, and four to six inches apart. They are -more convenient when made to slide like drawers. - -The different species of one genus are gummed on one or more of the -white sheets and placed within the folded manila paper, which serves -as a cover. Each specimen should be signed with its name, place, and -date of collection, thus: - - /C. rubrum./ Bar Harbor. Aug. 12, 1899, - -the generic name being indicated by its initial capital letter and -the specific name written in full. To this are often added the -[pg018] name of the collector and some interesting comment. On the -lower left-hand corner of the genus-cover is written the generic name -in full and the species of that genus which the cover contains, thus: - - /Ceramium/ /C. rubrum/ - /C. strictum/ - /C. diaphanum/ - -The genera of an order are then placed within a cover and labeled -in the same way, the legend then having the name of the order on -the left and the genera on the right of the bracket, [TN: see -Transcriber's Note.] thus: - - /Rhodymeniaceae/, suborder /Ceramieae/ - - /Callithamnion/ - /Griffithsia/ - /Ceramium/ - -When the order is a large one the genera are distributed through as -many covers as may be necessary. The covers are then arranged on -shelves in the regular order of their classification, and each shelf -is labeled with the order it contains. Herbarium-sheets cost at -retail one dollar per hundred. Genus-covers cost at retail one dollar -and eighty cents per hundred. [pg019] - - - - -III - -CLASSIFICATION - - -The first great biological division is into kingdoms, namely, the -animal kingdom and the vegetable kingdom. Then by classification the -vast number of existing animals and plants are grouped so as to give -each individual a definite place. By this system a beautiful order -is established, which enables the student to find any particular -animal or plant he may wish to study, and also to know its general -characteristics from the name of the group to which it belongs. - -In broad generalization, objects of wide dissimilarity are recognized -as belonging to the same kingdom, as do trees and grasses, or as -do birds and fishes. Certain trees or grasses and certain birds or -fishes have such points of resemblance that they plainly show that -they belong to subdivisions. The most untutored people recognize -these distinctions, but the naturalist goes further and finds points -of distinction which the casual observer overlooks. - -The animal kingdom has a varying number of divisions, called -/branches/, /subkingdoms/, or /phyla/. Some late authors have -admitted twelve divisions, and have given them the name /phyla/. Each -phylum is composed of a group of animals with a plan of structure -which is common to themselves, but differs from that of the animals -of all other phyla. - -The higher animals begin with the twelfth phylum, namely, the -/Chordata/, or vertebrates. These animals have a spinal column, or -series of vertebrae, while the lower animals, or invertebrates are -without a spinal column, and depend for stability [pg020] upon -muscles or coriaceous or calcareous coverings. The vertebrates -are first represented in the fish-like forms. Bilateral symmetry, -however, or the uniform arrangement of parts on each side of -a central axis, exists in several groups which are below the -vertebrates, the first pronounced example being found in worms. -Groups lower than worms have their organs arranged around a central -axis or radiating from it, and were once all classed as /radiates/. - -An animal is classified in accordance with its morphology, anatomy, -histology, and embryology. Morphology determines its general shape, -the position of its limbs, eyes, and mouth, and the covering of -its body; anatomy, the arrangement of its internal organs, such as -the position of its heart, lungs, stomach, etc.; histology, the -character of the tissues of the body; and embryology, the method of -the development of the animal from the embryo to maturity. It is only -after these exact discriminations have been made that the groups are -arranged. Owing to the greater accuracy resulting from histology and -embryology (methods which have been employed only in later years), -many changes in classification have been made, and as science -advances will continue to be made. - -The primary groups are based on broad general characteristics, -but their divisions and subdivisions are determined by closer -distinctions. Animals having shells differ from those having a -cartilaginous or those having a crustaceous covering, and are placed -in different groups. Yet mollusks having a single or a double shell, -having spiral or flat forms, living on land, in fresh water, or in -the sea, while differing from one another, are all of one group. -Lobsters and crabs, although both have crustaceous coverings, are -very unlike; and again, there are many species of both lobsters and -crabs. - -To group individuals, noting resemblances as well as differences, -a system of classification has been arranged with the following -divisions: - -Kingdom, Phylum, Class, Order, Family (or Suborder), Genus, Species. -[pg021] - - - - -IV - -ANIMAL LIFE IN ITS LOWEST FORMS - - -The biological division, or discrimination, between animal and -vegetable life, is based on the manner of assimilating food. Plants -feed upon mineral substances, or, in other words, assimilate -inorganic matter, while animal life requires for its support -vegetable or some other organic matter. - -Animal as well as vegetable life in its lowest forms begins with -one-celled organisms, which are called respectively /Protozoa/ (first -animals) and /Protophyta/ (first plants). Both of these divisions -are composed mostly of microscopic objects, and, together with other -minute forms of life of the marine species, constitute a great part -of the /plankton/, or free-floating organisms of the sea. These -minute organisms seem like connecting-links between the two kingdoms. -They were claimed by both botanists and zooelogists until the use of -the microscope made close observation of minute structure possible. - -Among the small animalcules of the phylum /Protozoa/ are some which -are familiar to all by name, such as the /Infusoria/, which are -most interesting creatures to examine in a drop of water under -the microscope. A more tangible example of the /Protozoa/ are the -/Foraminifera/. /Foraminifera/, like diatoms, have a shell-like -covering, and these shells, among the most plentiful of which are -those of the genus /Globigerina/, fall, as do those of diatoms, in -immense numbers to the bottom of the ocean, and form respectively -what are known as /Globigerina/ and diatomaceous ooze. In course of -time the sedimentary strata become fossilized; thus, the stone of -which the city of Paris is built consists of fossilized [pg022] -foraminifers, and the pyramids of Egypt are built of nummulites, -another genus of /Foraminifera/. It is estimated that an ounce of -this deposit contains four millions of these protozoans, so it is -impossible to conceive the numbers of once living animals represented -in the tombs of the Pharaohs. Telegraph-cables raised from the depth -of two miles bring the message to naturalists that the bottom of the -ocean at that depth is composed of little else than the calcareous -shells of /Foraminifera/. - -Many of the lower animals resemble plants in form. Hydroids and -polyzoans are often gathered and preserved as seaweeds. Corals, -sea-anemones, and holothurians are curiously like plants. For a time -the confusion about the division of animals and plants was partly -owing to this resemblance of forms, and the theory of the animal -nature of corals was for a long time considered to be refuted by -the testimony of a naturalist who declared that he had seen them -in bloom. Later this class of animals was believed to occupy an -intermediate sphere and partake of the characteristics of both -kingdoms. The name zooephyte, meaning "animal-plant" or "mingled -life," was adopted because of these resemblances and was formerly -applied to these forms only. To-day it has a broader application. -There is still a neutral class, called /Protista/, comprising -organisms which have not yet been classified as plants or animals. -[pg023] - - - - -V - -DISTRIBUTION OF ANIMAL LIFE IN THE SEA - - -All living things which inhabit the sea have their appointed -boundaries, and the localization of marine life is as distinct as -is that of terrestrial life. Each kind of beach has forms of life -peculiar to itself. Those animals which inhabit rocky shores or stony -beaches or sand or mud may be looked for anywhere under similar -physical surroundings. They are, however, modified by climatic -conditions, and in wide ranges differ in genera and species. The -rocky coast of Maine has a class of sea-urchins and starfishes -which are different from those which live on the rocky shores of -the northern Pacific coast, yet they are all easily recognized as -belonging to the same family, and a description of typical forms is a -sufficient guide to the recognition of their relationships. - -A bathymetrical division defines the classes of animals according -to the depth of water in which they live. Those which live near the -shore are /littoral/ species, those of the broad sea are /pelagic/, -while those living at great depths are /abyssal/. - -Their modes of life are distinguished by other terms. Those which -float at or near the surface and are carried about by the currents, -like the jellyfishes and the minute organisms mentioned elsewhere, -are /plankton/. Strong swimming animals which move about at will are -/nekton/. Those which are fixed, like oysters, sponges, etc., and -those which crawl on the bottom, like crabs, echinoderms, etc., are -/benthos/. - -Again, geographical divisions are named, in recognition of climatic -influences. The /boreal/ fauna and flora on the Atlantic [pg024] -coast extend from Cape Cod northward; the /American/, from Cape Cod -to Cape Hatteras; the /West Indian/, from Cape Hatteras southward. On -the Pacific coast the divisions, without definite names, are from the -Isthmus to Acapulco, Acapulco to the Gulf of California, Cape Lucas -to the Strait of Fuca. These divisions merge at indefinite lines, -but the above limits are generally accepted as the points of broad -division. - -The shore or littoral fauna is especially abundant and comprises -more species that are curious in form and beautiful in color than -the others. The invertebrates of the deep sea are mostly transparent -and of a blue or violet tint, while the fishes are gray or bluish -above and white beneath, which renders them inconspicuous to their -enemies. [pg025] - - - - -VI - -SOME BOTANICAL FACTS ABOUT ALGAE - - -The vegetable world is separated into two great divisions: -/thallophytes/, or plants having no distinction of leaf or stem, -and /cormophytes/, or plants which have leaves and stems. All -thallophytes that live in the water and are nourished wholly by water -are called /algae/. - -A second great division of plants is into /cryptogams/, or those that -have no flowers, and /phanerogams/, or those that have flowers, by -means of which seeds are produced and successive generations of plant -life continued. - -/Thallophytes/ and /cryptogams/ comprise the lowest and simplest -vegetable organisms. Algae belong to both these divisions; to the -first because they have neither stems nor leaves, and to the second -because they have no flowers. - -The lowest forms of algae are microscopic in size, each individual -being a single cell; but in the ascending scale they attain curious -and beautiful shapes, some growing to a gigantic size and in forms -that resemble shrubs and trees. The green surface commonly seen on -the shady side of trees, on stone steps, and in other damp places is -one of the species of algae which consist of a single cell. This plant -or cell divides, and the separate divisions divide and subdivide -again and again, and in time the aggregate number is great enough to -spread over a comparatively large surface, and thus become visible -to the naked eye. This plant, the /Pleurococcus vulgaris/, is a -fresh-water alga. The /Protococcus nivalis/, or red snow, described -on page 33, is a closely allied species. The green and blue-green -scums and slimes on [pg026] brackish ditches and on the stones and -woodwork of wharves are also species of the lowest orders of algae -and increase by cell-division. Many of them are in colonies incased -in gelatinous matter. These, together with plants of a little higher -order, though still of low organization, the /Confervaceae/, form a -large part of the green vegetation between tide-marks. - -The vegetative body of a thallophyte is a /thallus/, and corresponds -to stem and leaf. It is also called a /frond/. What corresponds to -the root of flowering plants is in algae a disk or conical expansion -of the base of the plant. It is simply a holdfast by which the frond -attaches itself to any submerged material. The algae which grow on -sandy shores and on corals have holdfasts which branch like fibrous -roots and penetrate porous substances in all directions; but this -is only for greater stability, and is an adaptation to the habitat. -Holdfasts do nothing for algae other than the name implies, whereas -real roots absorb the nourishment upon which plants live. Algae are -nourished by the substances held in solution by the water which -surrounds them. - -Algae are the lowest and simplest in organization of all plants, -because they are composed of but one class of cells, such as in -flowering plants are called the /parenchyma/, or soft cells, these -being the ones which compose the pulp of the leaf. In the lowest -orders of algae single cells constitute individual plants, as in -/Pleurococcus/; but in the higher forms, such as /Sargassum/, they -arrange themselves in such a variety of combinations as to resemble -plants which have leaf and stem. The botanical distinction is that in -leaf and stem there would exist the woody and the vascular cells as -well as the parenchyma cells. - -Beginning with plants composed of a single cell, the next development -is into filamentous plants, which are single thread-like rows of -cells, as in /Cladophora/. In /Ulva/ is seen the earliest type of an -expanded leaf. The cells are here arranged in a horizontal surface of -plate-like or ribbon-like shape. - -In /Ulva/ there is a double layer of cells. The layers separate in -/Enteromorpha/, giving a hollow or tubular form. In /Monostroma/ a -double layer is opened or torn apart, giving a frond with a single -layer of cells. [pg027] - -The stem-like forms of certain algae are composed of cylindrical -cells which combine or grow in a longitudinal direction chiefly. -Sometimes the cells are arranged evenly, in which case the stem -seems articulated, as in some species of /Ceramium/. Again, they are -irregularly placed, so that the stem appears solid. - -The highest types of algae in the differentiation of parts, or -vegetative forms, are to be found in the /Fucaceae/, of the brown -seaweeds; the highest in the reproductive development, in the red -class. - -Reproduction by cell-division, in which the organism itself breaks up -into two or more individuals, is called /vegetative reproduction/. -Higher forms reproduce by spores, or germ-cells, which give rise to -new individuals on germination. - -The substance of an alga is more or less firm, according as the -vegetable mucus or gelatinous matter it contains has more or -less consistency; it is /membranaceous/ when the gelatine is -scant and glossy, /gelatinous/ when it is abundant and fluid, and -/cartilaginous/ when it is hard. - -Some algae are annuals; a few are perennials, and cast off and renew -their laminae every season. Many plants present quite a different -appearance at different seasons of the year, and so are often -difficult to identify. Those which form spores throw off these -isolated cells, which sink or are washed to positions where they -germinate and begin their cycle of life. Many of the spores begin -their growth at once, without regard to season, so the species is -ever present. [pg028] - - - - -VII - -NAMING OF PLANTS - - -The real or technical names of plants, which at first appear long and -unpronounceable, are in reality simple when the system of naming is -understood. Every plant has a /generic/ and a /specific/ name. The -generic name is analogous to the surname of a person, such as /Smith/ -or /Jones/. The specific name is analogous to the Christian name of -a person, such as /John/ or /James/. The specific name never stands -alone, and would have as little designating character as John ---- or -James ----. - -This is called the /binomial/ (two-name) /nomenclature/. It was -introduced by Linnaeus, and greatly simplified the system of naming. -The rule in scientific nomenclature is that all names must be Latin -or Latinized. This gives a universal language by which scientists of -all countries understand one another. - -The names of classes (the highest groups) and subclasses are -adjectives or adjective nouns, expressing the most prominent -characteristic of the class or subclass. Thus the four subclasses of -the class /Algae/ are: - -/Cyanophyceae/ (subclass of blue-green algae). - -/Chlorophyceae/ (subclass of grass-green algae). - -/Phaeophyceae/ (subclass of dusky-brown or olive-green algae). - -/Rhodophyceae/ or /Florideae/ (subclass of red algae). - -Orders are, with few exceptions, the names of genera with the -termination /-aceae/, as: - -/Ulvaceae/, from the genus /Ulva/. - -/Ectocarpaceae/, from the genus /Ectocarpus/. - -/Gigartinaceae/, from the genus /Gigartina/. [pg029] - -Suborders, or groups between orders and genera, terminate in /-eae/. -Names of genera are nouns or words taken as nouns. They are derived -from any source,--from prominent or peculiar characteristics, from -localities, or from names of botanists,--or they may be wholly -arbitrary. Personal generic names are divested of titles and take -a final /a/, or, in many cases, for euphony, /ia/. Thus, /Ulva/ is -the Latin for "sedge"; /Ectocarpus/ is from two Greek words meaning -"fruit outside"; /Corallina/ means "coral-like"; /Grinnellia/ is -named for Mr. Henry Grinnell. - -The specific names are commonly adjectives, but sometimes they are -nouns, and occasionally are the names of the botanists who first -described the plants, in which case the name terminates in /-i/ or -/-ii/. The specific name always follows the generic name, thus: - -/Ectocarpus Hooperi/, a species of /Ectocarpus/, first described by -Mr. Hooper. - -/Grinnellia Americana/, a species, peculiar to America, of a genus -named for Mr. Grinnell. - -/Griffithsia corallina/, a species resembling coral, and belonging to -a genus named for Mrs. Griffiths. - -With regard to the four subclasses mentioned above, it should be said -that algae are strictly classified in accordance with their methods -of reproduction; but since allied species have, with few exceptions, -the same color, the classification by colors is generally adopted as -convenient and sufficiently precise. - -Familiar, or, in technical language, "vulgar," names are very -generally given to land plants, and especially to flowers; but -seaweeds are less in sight than flowers are, and so, save in a -few instances, have not been named except by the man of science. -To remember the scientific names will not be found difficult, for -without effort or special pains to acquire the new vocabulary, the -names, like those of new personal friends, will insensibly become -fixed in the memory. - -In the body of this work each of the groups (class, subclass, order, -etc.), in the classification of both animals and plants, is indicated -by a special kind of type. [pg030] - - - - -VIII - -DISTRIBUTION OF ALGAE - - -The eastern coast of North America has been divided into four -sections, which correspond to the distribution of the algae which are -characteristic of each section. The boundary-lines are not precise, -since some species of each section extend beyond the defined limits; -but arctic forms are not generally found south of Cape Cod, nor -can tropical varieties be expected north of Cape Hatteras. On the -intervening coast, however, there are some species common to both -sections. The divisions are: (1) Greenland to Cape Cod; (2) Cape Cod -to Cape Hatteras; (3) Cape Hatteras to Cape Florida; (4) the Florida -Keys and the shores of the Gulf of Mexico. - -On the Pacific coast such distinct lines of demarcation do not exist, -there being no such natural barriers as are formed on the eastern -coast, first by Cape Cod, and, second, by the stretch of sand-beach -which extends from New York to Charleston, and which divides sharply -the climatic varieties. - -The whole shore is again divided laterally into three distinct belts, -called the /littoral/, the /laminarian/, and the /coralline/ zones. -The first or littoral zone covers the space between tide-marks. -Vegetable life in this zone is subjected first to exposure to the -sun and air, and even to desiccation, and then to entire submergence -at constantly recurring periods. The rockweeds (/Fucus/), which -are so plentiful in this zone, are very gelatinous, nature having -apparently provided the gelatine to protect the cells of the plant -from the effects of the alternating extreme conditions. /Fucus/ and -/Enteromorpha/ predominate in this zone. [pg031] - -The laminarian zone extends from low-water mark to the depth of -fifteen fathoms. The /Laminariaceae/ and the beautiful red algae -(/Florideae/) grow here. - -The third or coralline zone extends to the depth of about fifty -fathoms. The algae of this zone, the nullipores, are incrusted with -a deposit of lime which gives them the appearance of corals; and, -singularly enough, the corals, which are animal forms, simulate plant -life. - -Again, algae have special habits and demand certain climates and -seasons for their growth. Algologists register the place where a -specimen is found, and in this way localities have been pretty well -determined. However, great exactness has not been reached, and the -collector is ever watchful to find an alga in some undiscovered home -within the given range. Although algae grow from extreme high-water -mark to the depth of fifty fathoms, almost every variety may be -found on the beach, those growing in deep water being frequently -torn off and washed ashore by the waves. The heaps of sea-wrack -will often reward one who examines them carefully for deep-water -species. Seaweeds are most abundant on rocky shores, particularly -where there are stratified rocks with crevices, which afford shelter -from the waves. Rock pools often contain beautiful varieties of the -more delicate species. Red algae will sometimes be found on the shady -side of these pools. Sand-beaches are unfavorable to the growth of -seaweeds, but fronds which have been carried long distances by the -currents will frequently be found on such shores. [pg032] - - - - -IX - -SOME PECULIAR AND INTERESTING VARIETIES OF ALGAE - - -The species of seaweeds that are known and classified are said to -number several thousands. These plants, which have neither vessels -for the conduction of fluids, nor fibers, consisting simply of -the first vegetable element, the cell, have, notwithstanding this -limitation, assumed a great variety of forms. In size they vary -from one one-thousandth of an inch in diameter, the smallest green -plants known, to those which exceed in length the height of the -tallest trees and form dense submarine forests, which in places make -comparatively deep water impassable for boats. In texture they vary -from a jelly- to a paper- and a leather-like consistency. In color -they have all the shades of green, brown, and red. - - -DIATOMS AND OTHER MINUTE ALGAE - -Among the smallest algae are diatoms. They are microscopic in size, -but exist everywhere in both salt and fresh water, and are infinite -in variety as well as in numbers. They have a silicious, shell-like -covering, which divides and subdivides in their reproductive growth, -forming varied shapes which are exceedingly beautiful and interesting -to examine under the microscope. In vast numbers they float on the -surface of the sea, and, together with other minute free-floating -organisms, form the basis of food-supply for fishes. Their -indestructible shells fall to the bottom of the sea, forming large -deposits, which in time become fossilized. The city of Richmond, -Virginia, is built upon [pg033] a fossiliferous bed of diatoms, -which measures twenty to eighty feet in depth and several miles in -length. - -Associated with diatoms, in fresh water, are desmids, which are green -in color and resemble the diatoms except in having a cartilaginous -instead of a silicious covering. Another minute organism, /Pyrocystis -noctiluca/, is luminous and is said to produce the beautiful -phosphorescent effects seen in tropical seas. /Trichodesmium/ is a -little alga which periodically occurs in great numbers, giving the -water a red appearance, as in the Red Sea, which is said to derive -its name from this circumstance. - - -RED SNOW - -In the high latitudes of the arctic regions, also on snowy mountains -at altitudes where all vegetable life is supposed to be extinguished, -there sometimes appears a redness on the surface of the snow, which -in some cases extends for many miles. At a certain place in Greenland -the color was so vivid that an arctic voyager named the locality the -Crimson Bluffs. - -The strangeness and almost sudden appearance of this color in the -snow have been so unaccountable to uninformed observers that it has -been ascribed by them to the falling of bloody snow and has been -regarded with superstition. The redness is caused by the growth of -one of the smallest of plants, the /Protococcus nivalis/. It is a -simple one-celled alga containing protoplasm and endochrome (red -coloring-matter). It grows by cell-division, the cell dividing into -four, eight, or sixteen parts on a quaternary scale. Each part -acquires a new covering while within the mother cell, and when it -emerges it is a complete individual and ready to repeat the process. -Only a few hours are required for its growth and development; hence -its increase is rapid, and it requires but a little time to make -itself manifest in those places where the conditions are favorable to -its existence. - - -THE SARGASSO SEA - -When the voyager reaches a certain region of the North Atlantic, -called the Sargasso Sea, he sails into a vast undulating marine -[pg034] prairie. Farther than the eye can reach is spread a -yellowish-brown vegetation which covers the water as grass covers the -plain. Sometimes these weeds are so thick as to impede navigation, -and, seen from a little distance, seem substantial enough to walk -upon. At other times, according to seasons and conditions of storm -and wind, they are divided into strips or into island-like masses, -with spaces of clear water between. If the sailor did not know the -special conditions existing here he might suppose he had come upon -dangerous shallows; or were the waters less turbulent he might dream -that he was floating among the water-weeds of an inland lake. - -This vast acreage of vegetation, as large as the continent of Europe, -lying southwest of the Azores and extending between the Canary and -the Cape Verde Islands, was first reported by Columbus, and takes its -name from the floating plant of which it is composed, the /Sargassum -bacciferum/, a species of the order /Fucaceae/, commonly known as -gulfweed. Columbus's sailors took fright at the marvelous appearance -and wished to turn back, thinking they had reached the end of the -navigable ocean. They thought, if land were beyond, it was guarded -by shoals, and that the weeds concealed dangerous rocks. Columbus -threw out two hundred fathoms of line, but did not reach bottom, -and continued on his course for fifteen days before emerging into -clear water. From that day to this the Sargasso Sea has attracted -the attention of all navigators. It is especially interesting to -scientists. The physicist finds there the phenomenon of the ocean -currents holding in a vortex this immense mass of seaweed, the -zooelogist finds a great pasture in whose protecting shelter are -living and breeding countless numbers of marine animals, and the -botanist is puzzled because the source of this species of plant is -clouded with doubt. - -[Illustration: PLATE II. Macrocystis pyrifera. Agarum Turneri. -Nereocystis Luetkeana.] - -According to one theory, the plants are dislodged by the tempests -from terrestrial beds and carried by the Gulf Stream into the -huge eddy; but since there does not exist enough of the attached -plants of this species to supply the vast accumulation, another and -more generally accepted theory is that the gulfweed lives also a -pelagic life and adapts itself to the conditions of the [pg035] -floating state, thus dispensing with the disk-like root, as it -needs no holdfasts, and propagating solely by lateral and axillary -ramification. - -There are said to be one hundred and fifty species of /Sargassum/, -but /S. bacciferum/ alone constitutes the beds of the Sargasso Sea. -The plant is the most highly differentiated of any seaweed, in that -it more nearly approaches the true leaf and stem, and is described -botanically as follows: Frond furnished with distinct, stalked, -nerveless leaves and simple, axillary, stalked air-vessels. The -integument is leathery, and the color brown of varying shades. The -most striking peculiarity is the abundance of globular cells. These -berry-like air-bladders give the plant buoyancy enough to support the -weight of its innumerable guests. (Plate XVI.) - - -THE LAMINARIACEAE - -In the laminarian zone, described above, grow the /Laminariaceae/, an -order of brown seaweeds, some of whose genera grow to enormous size, -and in some places form dense submarine forests. Darwin speaks of the -good service rendered by these plants to vessels navigating stormy -coasts, where often they act as natural breakwaters, and again as -buoys designating dangerous rocks near the shore on which they grow. -The seaweeds belonging to this order, commonly known as oarweeds, -tangle, devil's-apron, and sea-colander, are frequently seen twelve -to twenty feet in length, and others are measured by fathoms. One -of the giant plants is /Nereocystis Luetkeana/, which occurs on -the northwest coast. It has a stalk, sometimes three hundred feet -in length, which bears on its extremity a barrel- or cask-shaped -air-vessel, six or seven feet long, from the surface of which a tuft -of fifty or more forked laminae grows to a length of thirty or forty -feet. The stem which anchors this immense frond is so small that the -Aleutian Indians use it for fishing-lines. The sea-otter makes his -home on its huge air-vessel, and the plant is called by the Russians -the "sea-otters' cabbage." - -But the longest of all known plants is the alga /Macrocystis/. Its -thin naked stem, the diameter of which seldom exceeds one quarter -[pg036] of an inch, is reported by one author to be seven hundred -feet in length, by another fifteen hundred feet. It is terminated -by a lamina fifty feet long, resembling a pinnatifid leaf, each -leaflet of which, at its point of division on the stem, expands into -an air-vessel as large as an egg. These air-vessels sustain the -immense frond which floats on the surface of the water, its leaflets -depending in a vertical position from the stem. /M. pyrifera/, the -only species, is found in the Southern oceans and on the Pacific -coast of North America. - -/Lessonia/, another genus, resembles a palm-tree. It grows erect to -a great height and has a stem like the bole of a tree. It branches -in a forking manner and has depending from its branches laminae two -or three feet long. The large stems from which the laminae have been -torn by the storms, and which have been cast ashore on the Falkland -Islands, as described by Sir Joseph Hooker, resemble driftwood, as -they lie in piles three or four feet high and extending for many -miles. - -/Agarum/ and /Thalassiophyllum/ are arctic genera, but they are found -within our limits, the former in the North Atlantic. It has a simple -but enormous leaf-like frond. The latter, which is found on the North -Pacific coast, has a compound frond. Both are characterized by their -fronds being perforated throughout with holes, giving them the name -of sea-colander. [pg037] - - - - -X - -USES OF ALGAE - - -Water covers two thirds of the surface of the earth, and algae, with -a very few exceptions, constitute the whole vegetation which exists -in that enormous area. They have, therefore, an important part to -perform in the economy of nature. Algae do not, like land plants, -derive their nourishment from the soil to which they are attached, -but from substances held in solution by water. In their growth they -effect changes in the water analogous to those effected by land -plants in the air; that is, they change so-called impurities in the -water into materials essential to animal life. The function of plants -is that of transforming or manufacturing inorganic matter, which they -assimilate, into organic matter (such as starch, albumen, sugar), -which forms their own structure and which is the food essential to -animals. In this process, plants inhale carbonic acid gas which -animals breathe out, and exhale oxygen which animals breathe in. -Plants feed on mineral substances and furnish vegetable food, thus -keeping up the balance of life. - -Fresh-water algae have a like economic value. The green surface on -stagnant pools is a vegetable growth whose function is to assimilate -the matter which makes the pool offensive. A submerged district soon -becomes covered with scum, or minute plants (/Sphaeoplea annulina/), -which grow with great rapidity, using up the materials of the -decaying vegetation, and in great measure counteracting the ill -effects, in the atmosphere, of such decay. When the waters subside, -the plants shrivel up and appear like thin paper covering the ground. -This ephemeral substance soon [pg038] disappears, without giving -evidence of its nature in dust or gases, its body seeming to be a -machine which transmutes, but does not hold, the substances on which -it grows. - -Algae, as has been said above, grow in definite zones, and each -zone has also a definite animal life which finds there its food. -Darwin says: "In all parts of the world a rocky and partially -protected shore perhaps supports in a given space a greater number -of individual animals than any other station." And speaking of the -/Laminariaceae/, he adds: "I can only compare these great aquatic -forests of the southern hemisphere with the terrestrial ones in the -intertropical regions. Yet if in any country a forest was destroyed -I do not believe nearly so many species of animals would perish as -would here from the destruction of the kelp." The same may be said of -the Sargasso Sea, where millions of living creatures make their home. -In every kind of marine fauna there are species which derive, if not -the whole, at least a part of their nourishment from the seaweeds. - -The vegetation in the narrow boundary of the three zones is -palpably inadequate to supply the needs of the animal life which -exists in deeper waters. But over the broad area of the ocean -there exists a vast number of pelagic, free-floating algae, which, -although microscopical in size, are almost infinite in numbers. -In illustration of this it has been estimated that, although they -are not especially numerous in the Sargasso Sea, yet if all the -seaweed there were gathered into one mass and the free-floating -algae into another, the bulk of the latter would exceed that of the -former. The pelagic flora consists of /Diatomaceae/, /Protococcaceae/, -/Peridinieae/, and others. Undoubtedly it is on these pastures that -fishes feed, as well as other organisms which in turn are food for -fishes. - -/Fucus/ and /Laminaria/ constitute the kelp from which iodine is -obtained, and were at one time the source of the potash of commerce. -/Fucus vesiculosus/ is a constituent of a medicine used as a cure for -obesity. /Chondrus crispus/, commonly known as Irish moss, was a few -years ago generally used as an article of diet. /Porphyra vulgaris/ -(laver) is used by the Chinese for soups. /Rhodymenia palmata/ -(dulse) is an article of food in Ireland and Scotland. [pg039] -/Gracilaria spinosa/ is used by birds, allied to the swallows, for -making their nests--the edible nests found in large numbers on the -islands of the Indian Archipelago, especially in the caves on the -shores of Java, and gathered and sent to China, where they bring -large prices and are used in making the famous birds'-nest soup. -/Gracilaria lichenoides/, also a species of the Eastern seas, is -the source of agar-agar, a preparation used in laboratories as a -culture-medium for bacteria. Fossil diatoms are ground and used for -polishing-powders. Seaweeds are everywhere used by farmers on the -coasts as fertilizers. [pg040] - - - - -XI - -COLLECTING AT BAR HARBOR - - -The beautiful coast of Maine is a particularly good field for -shore-collecting. The rocky coast harbors the boreal fauna and flora -which depend upon such physical conditions, and the shores at Bar -Harbor are typical of those found elsewhere in northern New England. -The rocks give shelter from the beating surf, while life has exposure -to the cold, pure waters of the arctic current. Everywhere along -the shore, rock pools are to be found. These are perhaps the most -fascinating of all spots to the collector. They are veritable gardens -of the sea, where species flourish which naturally belong to deeper -water, but which find in such pools conditions suitable to their -existence. - -At Bar Harbor one well-known and frequently visited rock pool is -found in Anemone Cave. Entering a field at Schooner Head, one -turns to the right and follows the rocky shore for two or three -hundred feet. It is difficult to take this short walk without being -constantly diverted and delayed by the various attractions one meets, -such as the tide-pools, the barnacles which in places whiten the -rocks, the periwinkles, the purpura shells, and the curious algae; but -at last one arrives at a cavern under an overhanging rock. Here is a -large tide-pool which at first sight displays only a beautiful scheme -of color. It is carpeted with a bright-pink alga, /Hildenbrandtia -rosea/, which incrusts the basin of the pool. - -Interspersed with the pink are patches of a deep-red color, having -a velvety appearance, which are formed by another crustaceous alga, -/Petrocelis cruenta/. The water of the pool is of crystal [pg041] -clearness, and as one gazes into it one object after another comes -into view, until one is filled with astonishment at the number of -beautiful objects the pool contains. The little green balls, one -half of an inch to one inch in diameter, which look like small green -tomatoes scattered on the stones, are /Leathesia difformis/, an -alga which cannot be mistaken for any other. Bunches of /Corallina -officinalis/, which resembles coral, as the name indicates, are -abundant. This alga should be examined with a magnifying-glass. It is -covered with calcareous matter, and its peculiar form of growth is -beautiful and interesting. - -The fronds of the laminarian /Alaria esculenta/ are tiny here, -while just outside the cave they are to be seen several feet in -length, beating against the rocks in the swash of the waves. Thorny -sea-urchins (/Strongylocentrotus drobachiensis/) make green spots -which look like tufts of moss. Yellow and green sponges in little -cones are spread over small surfaces. Starfishes and ophiurans -are plentiful. The /Purpura lapillus/ and /Littorina litorea/ and -/rudis/ (periwinkles), so plentiful on this coast, are present. The -/Mytillus/ and the /Saxicava/ and the /Acmaea testudinalis/ are also -to be found. A green crab (/Carcinus maenas/) is snugly hidden in a -dark nook on the shady side of the pool, and many small crustaceans -scuttle away from under stones as they are lifted. The collector -is always anxious for uncommon, or rather less plentiful, species, -and here are found two specimens of nudibranchs, or naked mollusks, -/AEolis/ and /Dendronotus/. The /Chiton ruber/, a jointed mollusk, was -also found here, and five species of sea-anemones were counted. As -this is a favorite hunting-ground, the anemones have not been left -to attain full growth; but there are very many small ones which at -first are not distinguishable, as they retract their tentacles at the -slightest disturbance of the water and are then quite inconspicuous. -After a little time of quiet watching they will be seen putting out -their tentacles and expanding their beautiful flower-like forms. -It is useless to try to capture them uninjured, so tightly do they -adhere to the rocks, and the difficulty of preserving them in an -expanded form is so great that amateur collectors had better leave -them undisturbed to beautify the pool. [pg042] - -It was hard to resist robbing this rock pool, where the author in -half an hour counted twenty different species, and finally left, -feeling that its treasures were not half discovered; but collecting -should be done elsewhere, and this pool be guarded as a gem to be -admired and not to be despoiled. - -This pool in Anemone Cave, although so very attractive, is surpassed -in beauty and interest by pools on Porcupine Island, at the base -of the cliff. This place is somewhat difficult of access, and the -timid will not undertake the descent to it; but the enthusiastic -collector, who overlooks small obstacles, will be repaid by a visit -to this spot, where all the treasures of Anemone Cave are multiplied -many times over. These pools are resplendent with large anemones, -hydroids, nudibranchs, mollusks, echinoderms, crustaceans, and -algae. /Alaria esculenta/, several feet in length, is beaten to a -fringe against the rocks, and /Agarum Turneri/, the sea-colander, is -also found here, together with beautiful specimens of /Rhodymenia -palmata/, which is so plentiful that it reddens the rocks. - -A /Metridium marginatum/, the most common sea-anemone of this coast, -was taken here which measured six inches in diameter. This creature -threw out so many of the processes used for defense that it seemed at -first as though it were covered with some seaweed; but the worm-like -movements of these threads, which measured six inches or more in -length, soon disclosed their nature. - -On the more accessible shores of Porcupine Island are found the naked -mollusks (nudibranchs) /AEolis/ and /Dendronotus/. Clinging sideways -to the rocks just above high-water mark are many shells of /Littorina -rudis/. They are fastened to the rocks by a glutinous deposit along -the outer lip, and the peculiar exposure of the open end, as well -as the position above tide-mark, indicates that this animal is -undergoing transformation into a land species. /Littorina palliata/ -is abundant on the rockweeds (/Fucus/); some of the specimens are -banded with yellow, and all closely simulate the seaweed on which -they cling. Beautifully banded specimens of /Littorina litorea/ are -also plentiful. Among other shells which are abundant here as well as -elsewhere on this coast are /Purpura lapillus/, /Acmaea testudinalis/, -/Buccinum undatum/, /Mya arenaria/, and /Mytillus edulis/. [pg043] - -Under the rockweeds in small pools and crevices are the polyzoans -/Bugula turrita/ and /Membranipora pilosa/, and the hydroids -/Sertularia pumila/ and /S. argentea/. - -The seaweeds /Rhodymenia palmata/ (dulse) and /Desmarestia/ are -plentiful; also beautiful worms, crustaceans, and starfishes. - -A very interesting beach is found a few hundred feet south of Otter -Cliffs, to which an easy descent is made if one follows a pathway -leading to it through a grove adjacent to the drive. Here one will be -interested in the study of numerous and beautiful rock pools. - -Sea-urchins (/Strongylocentrotus drobachiensis/) seem to carpet some -of them, having the appearance of mossy tufts. Beautiful pink and -purple starfishes (/Asterias vulgaris/), brittle-stars (/Ophiopholis -aculeata/), sea-cucumbers (/Pentacta frondosa/), sea-anemones, and -crabs are abundant. If one lifts a stone the little crustaceans -/Orchestia/ and /Gammarus/ will hurry away, and very likely an -interesting worm or a nudibranch will be found. It is also most -interesting to watch the barnacles, which are below the surface, -reaching out their curled, feather-like feet in regular rhythmic -grasping motions. The common mussels (/Mytillus edulis/), which in -places blacken the shore, are beautiful under examination, and the -silky network or byssus which forms the anchorage should be observed. - -The rocks are hung so plentifully with /Ascophyllum nodosum/ -(rockweed) that its beauty is likely to be passed over unnoticed. -On the /Ascophyllum/ is growing in tufts /Polysiphonia fastigiata/; -other seaweeds, /Rhodymenia palmata/, /Chordaria flagelliformis/, -/Desmarestia aculeata/, /Corallina officinalis/, and /Ceramium/, are -so abundant that one forgets to value them at the moment. Higher up -on the beach the rocks are spotted with papery sheets, which, floated -out in water, prove to be the beautiful purple /Porphyra/. A fine, -dark colored, hairy scum on the rocks is /Bangia fusco-purpurea/. -Sometimes one finds here fronds of /Laminaria/ which have been washed -ashore. Various green algae are abundant. Even if not collecting, it -is well to carry a small tin pail to the beach and float out pieces -of the algae in order to observe carefully, if but for a moment, the -beautiful forms they have in their natural state. Watched for a few -minutes in a pail of water animals disclose curious [pg044] and -surprising forms and habits which are difficult to watch leaning over -a pool. - -Most of the various species mentioned above are common along the -whole shore, and may be looked for at almost any point where the -water is free from contamination. - -At the sand-beach are found species which do not inhabit the rocky -shore, as the sand-dollar (/Echinarachnius parma/), /Polynices/ -(/Lunatia/) /heros/, /Mya arenaria/, and others. After a storm -various deep-water forms are washed upon this beach. /Laminaria -digitata/, six feet long, is found here sometimes under these -circumstances. /Chordaria flagelliformis/, resembling long switches -of hair, floats from the rocks near the shore. To the left, on the -rock under the overhanging ledge, is a tide-pool which one would -hesitate to deface by touching a single specimen. So crystal-clear -is the water, so brilliant the /Hildenbrandtia/, so lovely the -/Corallina/, that all seem placed there to excite admiration. - -But most of all one should obtain the permission of the owner to -visit Rodicks Weir. Here is an immense natural aquarium, full of -living wonders. On a clear day, sunlight penetrates to the bottom, -and at low tide the whole contents of the weir are clearly seen as -one floats through the inclosed water-spaces. On the bottom are -sea-urchins, many of them with sticks or stones on their backs, which -the animals have placed there in the endeavor to conceal themselves; -starfishes feeding; and great numbers of whelks (/Buccinum undatum/). -Cuttlefishes dart rapidly about, and skates, sculpins, and other -fishes display their curious forms. Very likely a giant jellyfish -(/Cyanea arctica/) is entangled in the brush, so that one can examine -at short range its wonderful and beautiful parts. Other jellyfishes -may be closely scrutinized. - -The alga /Polysiphonia violacea/ floats in long feathery tufts from -the stakes. - -On the eel-grass are to be found /Lacuna vincta/ and the delicate -iridescent little shells of /Margarita helicina/. - -Every tide brings different species of the ocean fauna to temporary -imprisonment in this inclosure, so that it is difficult to say what -one may not chance to find in this interesting place. - - - - -PART I - -MARINE ALGAE - - - - -SEAWEED - - - When descends on the Atlantic - The gigantic - Storm-wind of the equinox, - Landward in his wrath he scourges - The toiling surges, - Laden with seaweed from the rocks; - - From Bermuda's reefs; from edges - Of sunken ledges - In some far-off, bright Azore; - From Bahama and the dashing, - Silver-flashing - Surges of San Salvador; - - * * * * * - - Ever drifting, drifting, drifting - On the shifting - Currents of the restless main; - Till in sheltered coves, and reaches - Of sandy beaches, - All have found repose again. - - LONGFELLOW. - - - - -I - -BLUE-GREEN SEAWEEDS (CYANOPHYCEAE) - -GRASS-GREEN SEAWEEDS (CHLOROPHYCEAE) - - -TABLE SHOWING THE CLASSIFICATION OF THE BLUE-GREEN SEAWEEDS DESCRIBED -IN THIS CHAPTER - - Class =ALGAE= - - Subclass =Cyanophyceae= (/Blue-Green Seaweeds/) - - Order =NOSTOCACEAE= - - Genera Species - - ^Spirulina^ - ^Oscillaria^ - ^Calothrix^ - ^Lyngbya^ ^L. majuscula^ - ^L. ferruginea^ - - -[pg049] - - -BLUE-GREEN SEAWEEDS - -The minute algae, which form patches of purple color on rocks, slimy -layers or spots on wharves, bluish-green slime on mud, emerald-green -films on decaying algae, blue-green slime on brackish ditches, and so -on, are various species of the subclass =Cyanophyceae=. The prevailing -color of these plants is blue-green, but some are purple, brown, or -pink. Some of them are gelatinous in texture and shapeless, others -have more definite forms; but all are too small to classify without -the aid of a powerful glass, and are not of special interest except -to the botanist. - - -GENERA ^Oscillaria^ and ^Spirulina^ - -The genus ^Oscillaria^ is so named from an oscillating movement which -these filamentous plants show when viewed under the microscope. They -are very delicate blue-green threads occurring singly, or in loose or -felt-like floating masses, or like slime or scum, on mud or woodwork. -In ^Spirulina^ the filaments are spirally twisted like a corkscrew -and also have a vibrating movement. /Spirulina/ is often found -growing with /Oscillaria/, and forms purple patches on wharves. - - -GENUS ^Calothrix^ - -("/Beautiful hair/") - -Filaments one tenth of an inch long, terminating in transparent -hair-like points, occasionally branching. The plant grows in fine -tufts or like a fringe on algae or in patches on rocks. Sometimes it -forms a spongy layer, again a velvety stratum. The color varies in -different species; it may be bright green, brownish-green, [pg050] -or dark bluish-purple. The genus is very common, and the plants are -often found on the bottoms of boats. - - -GENUS ^Lyngbya^ - -(/Named for Hans Christian Lyngbye, a Danish botanist/) - - ^L. majuscula^, mermaid's-hair. The filaments are curled or - crisped, long, thick, and tenacious, matted together at the base, - and blackish-green. The species grows in tufts on eel-grass and - algae, and is often found floating free. It is common in summer - everywhere south of Cape Cod and on the Pacific coast. - - ^L. ferruginea^ or ^aestuarii^. In this species the filaments are - thin, soft, and without stability (flaccid), so that they lie flat - like a thin stratum. They are verdigris-green in color, and are - found in brackish pools and ditches and on muddy shores near the - sea. [pg051] - - -TABLE SHOWING THE CLASSIFICATION OF THE GRASS-GREEN SEAWEEDS -DESCRIBED IN THIS CHAPTER - - Class =ALGAE= - - Subclass =Chlorophyceae= (/Grass-Green Seaweeds/) - - Order Genus Species - - =CONFERVACEAE= ^Ulothrix^ - - ^Chaetomorpha^ ^C. melagonium^ - ^C. aerea^ - ^C. linum^ - - ^Cladophora^ ^C. arcta^ - ^C. rupestris^ - ^C. gracilis^ - - =ULVACEAE= ^Ulva^ ^U. lactuca^ - ^U. latissima^ - - ^Enteromorpha^ ^E. clathrata^ - ^E. compressa^ - ^E. intestinalis^ - ^E. lanceolata^ - - ^Monostroma^ - - Group =Siphoneae= - - =VALONIACEAE= ^Chamaedoris^ ^C. annulata^ - - ^Anadyomene^ ^A. flabellata^ - - =DASYCLADACEAE= ^Acetabularia^ ^A. crenulata^ - - ^Dasycladus^ ^D. occidentalis^ - - ^Cymopolia^ ^C. barbata^ - - =UDOTEACEAE= ^Penicillus^ ^P. dumentosus^ - ^P. capitatus^ - ^P. Ph[oe]nix^ - - ^Udotea^ ^U. flabellata^ - ^U. conglutinata^ - - ^Halimeda^ ^H. tuna^ - ^H. tridens^ - ^H. opuntia^ - - =CODIACEAE= ^Bryopsis^ ^B. plumosa^ - - ^Codium^ ^C. tomentosum^ - - =CAULERPACEAE= ^Caulerpa^ ^C. prolifera^ - ^C. Mexicana^ - ^C. plumosa^ - ^C. Wurdemanii^ - -[pg052] - - -GRASS-GREEN SEAWEEDS - -"There can hardly be a more fascinating group of plants than this, -whether to the strictly scientific botanist or to the more catholic -lover of nature. The green algae are among the most widely diffused -of plant forms. They grow practically in every place where enough -moisture, together with light and air, is to be had. Between -tide-marks on almost every coast, floating on the surface of the deep -sea, covering damp earth, walls, palings, and tree-trunks, sticking -to the surface of leaves in the moist atmosphere of tropical forests -and jungles, and inhabiting almost every river, brook, pond, ditch, -or casual pool of rain-water in all quarters of the globe, are -members of this ubiquitous group to be found."[3] - -[Footnote 3: Kerner.] - -The grass-green seaweeds are more simple in structure, and therefore -are lower in order, than the red or brown algae. They are among the -lowest of all plants, many of them being minute single cells. They -abound in fresh as well as in salt water, and in this respect differ -from the other groups, the red and the brown algae being almost -exclusively marine plants. - -As one approaches the shore, the attention is often attracted by the -green mantle which covers everything overflowed by the tides. This -consists largely of the confervoid algae, which are very abundant and -are found almost everywhere. They are dense tufts of fine thread-like -plants, often matted at the base; sometimes they are sponge-like, -floating masses. - -The =Ulvaceae=, the plants next higher in order, are the first which -assume ribbon- and leaf-like expansions, and usually first engage the -attention of the collector. [pg053] - -In the green algae are found the extreme forms of one-celled plants. -In ^Pleurococcus^ the cell is microscopic in size. In the =Siphoneae= -the plant still consists of a single cell, but it attains large -dimensions and develops into forms resembling, in outward appearance, -leaf, stem, and root (see /Caulerpa/). - -Other plants consist of single rows of cells, called filaments -(=Confervaceae=), or of cells arranged in layers or flat surfaces, -called membranes (=Ulvaceae=). - - -ORDER =CONFERVACEAE= - -The silkweeds. This order is characterized by cylindrical cells -strung end to end, forming threads or filaments, branched and -unbranched. The plants inhabit both fresh and salt water, and are -very abundant and widely distributed. They grow in dense tufts, often -matted at the base. - - -GENUS ^Ulothrix^ - -A yellow-green, unbranched, decumbent, soft, hair-like fleece on the -surface of rocks, extending indefinitely. This genus differs from -/Chaetomorpha/ in the character of its filaments, which are soft and -gelatinous in ^Ulothrix^, but bristle-like and wiry in /Chaetomorpha/. - - -GENUS ^Chaetomorpha^ - -The frond is filiform; the filaments are coarse, rigid, and -unbranched. In some species the filaments grow straight and in -tufts from a definite base; in others they are twisted together -and are prostrate. Often they are found floating in masses. In ^C. -tortuosa^ the filaments are as fine as human hair, but rigid, and so -closely interwoven as to resemble a layer of wool on the rocks. The -cell-divisions give a striped appearance to the filaments when dry. - - ^C. melagonium.^ This species is dark green, with filaments erect, - coarse as a double bristle, and wiry; five to twelve inches long. - It is found in rock pools from Boston northward. It does not adhere - to paper in drying, and loses its color if immersed in fresh water. - (Plate III.) - - ^C. aerea.^ Yellowish-green, with filaments erect and less rigid - than [pg054] in /C. melagonium/, which it otherwise resembles; - tufts three to twelve inches long; cell-divisions very marked. This - species is found in rock pools from Cape Cod to New York Bay. - - ^C. linum.^ Bright green; filaments coarse, rigid, twisted - together, and prostrate. It is found floating in masses and forming - strata on rocks and gravel from New York northward. It is thought - by some that this, as well as ^C. picquotiana^, which it closely - resembles, is not a true species, but consists of the mature plants - of the species /C. melagonium/ and /C. aerea/, which have become - detached from their holdfasts and have continued to grow. (Plate - III.) - - -GENUS ^Cladophora^ - -("/Branch-bearing/") - -Frond filiform, branched. There are many species of ^Cladophora^, -which differ from one another in their branching, color, and size. -They abound on rocks at low-water mark, in tide-pools, in muddy -ditches, and on wharves. They are especially characterized by being -so profusely branched as to form tufts or spherical masses, by which -the collector can easily distinguish the genus. - - ^C. arcta.^ Bright, glossy green; filaments fine, erect, much - branched, two to eight inches long; tufts dense, more or less - entangled, and in bunches, giving a starry effect. The species is - common on rocks near low-water mark from New York northward. The - plants vary slightly in appearance with the season. (Plate III.) - - ^C. rupestris.^ Dark green; filaments straight, rigid, tufted; - branches crowded; many branchlets flattened against the filaments, - so that the alga somewhat resembles grass; five to ten inches long. - The cell-divisions show plainly. Plants of this species do not - adhere to paper in drying. They are found on rocks at low-water - mark, and are common on the northern New England coast. (Plate III.) - - ^C. gracilis.^ Bright yellow-green; filaments very fine, loosely - tufted, three to twelve inches long, soft, silky, much branched; - branches rather short, and branchlets more or less curved and - arranged in a comb-like manner. It grows on wharves, in muddy - pools, and on eel-grass. (Plate IV.) - -[Illustration: PLATE III. Chaetomorpha melagonium. Chaetomorpha linum. -Cladophora arcta. Cladophora rupestris.] - -[Illustration: PLATE IV. Cladophora gracilis. Ulva lanceolata. Ulva -lactuca, var. rigida. Enteromorpha clathrata.] - - -ORDER =ULVACEAE= - -The plants of this order are, with few exceptions, formed of celled -surfaces and show the earliest type of an expanded leaf. The cells -form thin membranes, which sometimes are broad surfaces of no -definite shape, sometimes are narrow and ribbon-like, or they may be -simple or branched tubes. When the membrane [pg055] consists of -a single layer of cells it is ^Monostroma^ ("one layer"); when it -consists of a double layer it is ^Ulva^; when the layers separate, -the thallus becomes hollow, and it is then ^Enteromorpha^. These -plants are mostly a brilliant grass-green in color, are silky in -texture, and are attached by a small disk to rocks and stones. They -abound everywhere, and are commonly known as /green laver/. - - -GENUS ^Ulva^ - -Frond a thin, silky, flat membrane, sometimes leaf-like, again an -extended surface of no definite shape. These are the largest green -algae. They are common everywhere. - - ^U. lactuca^, the sea-lettuce. Frond a flat membrane of various - shapes, sometimes orbicular, again deeply incised, often - ribbon-like; margin always much waved or ruffled. In the variety - ^rigida^ the frond is oval in outline, not very large, and quite - firm or rigid. The species is found on rocks exposed to the action - of the waves. (Plate IV.) - - ^U. latissima.^ Frond a flat, expanded membrane of indefinite - shape, but general outline oval, never ribbon-like; attains a - size of twelve to twenty-four inches; often deeply lobed, very - waved, often perforated with holes; membrane brilliant green, - thin, smooth, glossy. It grows apart or in tufts, and is found - everywhere, in all stages of growth. It is the largest species of - /Ulva/, and is very common on muddy shores. - - -GENUS ^Enteromorpha^ - -Fronds tubular, simple or branched, sometimes inflated. The tubes -vary in size in different species and also in the same species, some -being fine like a hair, others large, and flat or inflated. The genus -is widely distributed and very abundant. Species of ^Enteromorpha^ -grow on the bottoms of ships, and in nautical language are called -/grass/. - - ^E. clathrata.^ Fronds thread-like, tubular, branched, and branches - beset with numerous fine branchlets; densely tufted, soft. Common - everywhere. (Plate IV.) - - ^E. compressa.^ Fronds long, slender, branched, tufted; branches - simple, compressed, extending from main central branch, obtuse - at ends, but attenuated at base. The species is very abundant - everywhere, and is a useful plant for the aquarium. (Plate V.) - - ^E. intestinalis.^ Single, long, inflated tubes or sacs, obtuse at - the apex, very attenuated at the base; fronds often crimped and - twisted, resembling an intestine, whence the name. (Plate V.) - [pg056] - - ^E. lanceolata.^ Formerly called /Ulva Linza/. Frond narrow, - ribbon-like, six to twelve inches long, one inch to two inches - wide; blunt or pointed at apex, tapering at base; attached by a - disk; edges much ruffled; bright green, soft, thin. - - -GENUS ^Monostroma^ - -This genus resembles /Ulva/, but is more delicate since it -has but one layer of cells, as its name implies. The frond is -usually sac-like at first, then breaks apart, leaving a thin, -semi-transparent membrane of no definite shape. - - -GROUP =SIPHONEAE= - -The distinct and peculiar character of this group is that in each -individual the whole plant consists of but one cell. There are many -genera, some of which are plants of elaborate form and considerable -size, but always the one cell expands and branches without dividing -the elongated cavity with septa, or plates of division. In ^Caulerpa^ -the stability of the plant is secured by numerous fibrils which -emanate from the interior of the cell, forming a spongy network of -interlacing filaments. In other orders the branches gain support from -incrustation, from interlacing, and from cohering on the edges. - - -ORDER =VALONIACEAE= - -The algae of this order are found only in tropical or subtropical -waters. Their holdfasts resemble fibrous roots and penetrate the sand -or coral on which they grow. - - -GENUS ^Chamaedoris^ - - ^C. annulata.^ When young this alga consists of an annulated tube - formed of a single cell. The annular constrictions occur at short - intervals, giving it the appearance of being jointed. It grows to - the height of two to three inches, when it ceases to lengthen and - produces a dense mass of filaments, forming a head or spherical - tuft one inch or more in diameter. It is bright grass-green in - color, rather rigid and tough, and when mature is thinly coated - with carbonate of lime. The holdfast is a tuft of fibers. The - species is found at Key West and is a native of the West Indies. - - -[Illustration: PLATE V. Enteromorpha compressa. Enteromorpha -intestinalis. Enteromorpha intestinalis. Anadyomene flabellata.] - -[Illustration: PLATE VI. Acetabularia crenulata. Dasycladus -occidentalis. Penicillus dumentosus. Udotea conglutinata.] - - -GENUS ^Anadyomene^ - - ^A. flabellata.^ Frond composed entirely of branching filaments, - which unite and form an undulating, rigid membranaceous surface, - which seems like a network of veins. The species grows in bunches - on short stems in the fissures of tidal rocks, and at first view - resembles young /Ulva/. It is a very curious and beautiful alga, - and should be examined with a glass. It is one inch to four inches - in diameter when full-grown. (Plate V.) - - -ORDER =DASYCLADACEAE= - -This order also inhabits only tropical or subtropical seas. It is -placed in this group, although only the main axis is unicellular. -The one-celled axis is surmounted or encircled by whorls of minute -filaments or branchlets (/ramuli/), which protrude through small -holes and are either persistent or deciduous. In the latter case the -fallen filaments leave disk-like scars on the stem. - - -GENUS ^Acetabularia^ - - ^A. crenulata.^ This little alga resembles a mushroom of the - /Agaricus/ variety or gilled species, and so is easily identified. - It is thinly incrusted with lime and is found on rocks and coral, - within tide-marks, on the Florida reefs. When full-grown the stipe - is two to three inches long and the cap one half of an inch in - diameter. (Plate VI.) - - -GENUS ^Dasycladus^ - -Fronds destitute of calcareous matter, soft, cylindrical or -club-shaped; single unicellular axis, beset with fine filaments or -ramuli. - - ^D. occidentalis.^ Frond club-shaped, one to two inches high, one - half of an inch or less in diameter; covered with whorls of fine - filaments, making the fronds almost spongy; substance soft but - tough; dark green. These plants have been compared to foxes' tails. - They grow in bunches on rocks between tide-marks. (Plate VI.) - - -GENUS ^Cymopolia^ - - ^C. barbata.^ Frond branched, dividing regularly in pairs; thickly - incrusted with lime. Annular constrictions at short intervals give - the branches the appearance of strings of beads. Each section - is covered with pores or scars of fallen ramuli. The branches - terminate in tufts of fine filaments. [pg058] - - -ORDER =UDOTEACEAE= - - -GENUS ^Penicillus^ - -The merman's shaving-brush, characteristic of coral reefs. - - ^P. dumentosus.^ Holdfast much branched, like a fibrous root, and - penetrating deep into the coral or sand; stem short, thick, more - or less flattened, sometimes hollow, covered with velvety scurf; - top covered with loosely spreading tuft of soft filaments three to - six inches long, which branch repeatedly in pairs (dichotomous); - color deep green. When old, these plants are incrusted with a thin, - porous layer of carbonate of lime. (Plate VI.) - - ^P. capitatus.^ Holdfast a dense mass of fibers two or more inches - long; stipe one to five inches long, one fourth to one third of an - inch in diameter, usually cylindrical, sometimes wider at top than - at base, sometimes flattened; thickly incrusted with lime, which is - smooth and often polished; top a dense, spherical mass of filaments - one to two inches in diameter; filaments branching dichotomously, - and rigid from incrustation of lime. - - ^P. Ph[oe]nix.^ Stipe cylindrical, one to three inches long, - one fourth of an inch in diameter, thickly incrusted with lime, - smooth; capitulum or head ovoid, and composed of filaments which - are incrusted with lime and coherent, forming many distinct, flat, - wedge-shaped, level-topped, spreading laminae. This species is found - at Key West. - - -GENUS ^Udotea^ - - ^U. flabellata.^ Short, flattened stem, expanding into a broad, - fan-shaped, smooth frond, concentrically zoned; margin wavy; - thickly incrusted with lime. Abundant at Key West. - - ^U. conglutinata.^ Deeply descending root; stem expanding into - fan-shaped frond; entire, lobed, or irregularly torn; slightly - incrusted with lime. The frond is composed of longitudinally - parallel, adherent filaments, which are visible, giving a striated, - rough surface. (Plate VI.) - - -GENUS ^Halimeda^ - -This genus resembles the corallines externally, and is abundant on -coral reefs. It appears as if formed of separate parts, resembling -a series of heart- or kidney-shaped segments strung together. The -plants are more or less incrusted with lime. The branching holdfast -grasps particles of sand, and with them forms a solid ball. - - ^H. tuna.^ Articulations roundish or half kidney-shaped, one half - to three quarters of an inch broad; frond flat, smooth, and thinner - than most species; bright green; somewhat flexible. (Plate VII.) - - -[Illustration: PLATE VII. Halimeda tuna. Halimeda tridens. Bryopsis -plumosa. Codium tomentosum.] - -[Illustration: PLATE VIII. Caulerpa Mexicana. Caulerpa Wurdemanii. -Caulerpa plumaris. Caulerpa paspaloides.] - - ^H. tridens.^ Fronds solitary, erect; base composed of - confluent articulations; above divided into numerous branches - of articulations, which are all flat, and in one plane giving a - fan-shaped outline; middle joints wedge-shaped; upper ones divided - into three lobes, frequently bearing articulations at the summit of - each lobe; thinly incrusted with lime; color bright green. (Plate - VII.) - - ^H. opuntia.^ Articulations kidney-shaped, flat, rather thin; - margins scalloped; irregularly branched and spreading; dense tufts. - - -ORDER =CODIACEAE= - - -GENUS ^Bryopsis^ - -("/Moss-like/") - -There are said to be about twenty species of this genus. They are -distinguished by the manner of branching, but are not very definitely -marked. All are erect, one-celled, branching stalks, and are -feather-like in appearance. - - ^B. plumosa.^ Fronds branched twice or more; branchlets or pinnules - tapering as they rise on the stalk, giving a triangular outline; - stalk naked below; plants a vivid dark green in color, two to six - inches long, growing in tufts on wharves and stones at low-water - mark and in tide-pools. It is common along the whole Atlantic and - Pacific coasts. It is well to use salt water for mounting this - alga, since the green coloring-matter or granular endochrome with - which it is filled easily escapes. (Plate VII.) - - -GENUS ^Codium^ - - ^C. tomentosum.^ This is called the commonest seaweed in the world. - It is abundant in every latitude, yet it does not appear on the - eastern coast of North America. It is found on the gulf coast of - Florida and is plentiful on the Pacific coast. The fronds are often - a foot long, composed of closely packed, club-shaped branches - dividing in a forking manner, and densely covered with fine - filaments which give them a soft, sponge-like texture. (Plate VII.) - - -ORDER =CAULERPACEAE= - - -GENUS ^Caulerpa^ - -(/From two Greek words meaning "stem" and "creep"/) - -/Caulerpa/ is the only genus of its order, but it contains about a -hundred species, many of which resemble mosses, ferns, or cacti. Each -plant is composed of a single cell, however much it may be [pg060] -ramified. The frond consists of a prostrate stem, from the lower side -of which root-like fibers or holdfasts descend into the hard sand or -coral, and from the upper side leaf- and branch-like secondary fronds -arise. These plants grow luxuriantly in tropical waters, extending -over large surfaces, and are the chief food of turtles. (Plate VIII.) - - ^C. prolifera.^ Frond or lamina flat and leaf-like, two to four - inches long, one half to three quarters of an inch wide, either - simple or once forked; margin entire. Similar laminae spring from - the surface or from the edge or base of the different leaf-like - portions. Laminae rise from the upper side of the creeping, rooting - stem. Its substance is somewhat horny and translucent. - - ^C. Mexicana.^ Prostrate, creeping stem, with rootlets or holdfasts - below, and leaf-like fronds above; fronds simple or with one or - two branches deeply cut in narrow lobes nearly to the center. The - species abounds at Key West. (Plate VIII.) - - - - -II - -OLIVE-GREEN AND BROWN SEAWEEDS (PHAEOPHYCEAE) - - -TABLE SHOWING THE CLASSIFICATION OF THE OLIVE-GREEN AND BROWN -SEAWEEDS DESCRIBED IN THIS CHAPTER - - Class =ALGAE= - - Subclass =Phaeophyceae= (/Olive-Green and Brown Seaweeds/) - - Orders Genera Species - - =ECTOCARPACEAE= ^Ectocarpus^ ^E. littoralis^ - ^E. siliculosus^ - ^E. viridis^ - ^E. tomentosus^ - - =SPHACELARIACEAE= ^Sphacelaria^ ^S. cirrhosa^ - ^S. radicans^ - ^Cladostephus^ ^C. verticillatus^ - - =RALFSIACEAE= ^Ralfsia^ - - =ENC[OE]LIACEAE= ^Punctaria^ ^P. latifolia^ - ^P. tenuissima^ - ^P. plantaginea^ - ^Asperococcus^ ^A. echinatus^ - ^Phyllitis^ ^P. fascia^ - - =DESMARESTIACEAE= ^Desmarestia^ ^D. viridis^ - ^D. aculeata^ - ^D. ligulata^ - ^Arthrocladia^ ^A. villosa^ - - =DICTYOSIPHONACEAE= ^Dictyosiphon^ ^D. f[oe]niculaceus^ - - =ELACHISTACEAE= ^Elachista^ - - =CHORDARIACEAE= ^Chordaria^ ^C. flagelliformis^ - ^Mesogl[oe]a^ ^M. virescens^ - ^M. divaricata^ - ^Leathesia^ - ^Myrionema^ - - =LAMINARIACEAE= ^Chorda^ ^C. filum^ - - ^Alaria^ ^A. esculenta^ - - ^Agarum^ ^A. Turneri^ - - ^Laminaria^ ^L. longicruris^ - ^L. saccharina^ - ^L. digitata^ - ^Macrocystis^ - ^Nereocystis^ - ^Lessonia^ - ^Thalassiophyllum^ - - =DICTYOTACEAE= ^Dictyota^ ^D. fasciola^ - ^D. dichotoma^ - ^Zonaria^ ^Z. lobata^ - ^Taonia^ ^T. atomaria^ - ^Padina^ ^P. pavonia^ - ^Haliseris^ ^H. polypodioides^ - - =CUTLERIACEAE= ^Cutleria^ ^C. multifida^ - - =FUCACEAE= ^Himanthalia^ ^H. lorea^ - ^Fucus^ ^F. vesiculosus^ - ^F. serratus^ - ^F. furcatus^ - ^F. ceranoides^ - - ^Ascophyllum^ ^A. nodosum^ - ^Phyllospora^ ^P. Menziesii^ - ^Cystoseira^ ^C. expansa^ - ^Halidrys^ ^H. osmunda^ - ^Sargassum^ ^S. vulgare^ - ^S. Montagnei^ - ^S. bacciferum^ - -[pg064] - - - - -OLIVE-GREEN AND BROWN SEAWEEDS - - -This subclass contains some of the most remarkable of the seaweeds. -It is especially notable for the diversity of its plant forms, which -range from filaments to plants which appear to have stems and leaves -(/Sargassum/). The species vary in size from very small fronds to -those of immense size (the /Laminariaceae/). It includes /Fucus/ -(the rockweeds), a very conspicuous genus, which furnishes fully -three fourths of the vegetable covering of the tidal rocks in the -localities in which it grows. - - -ORDER =ECTOCARPACEAE= - -This order comprises many species of branched, filamentous plants, -some of which are of hair-like fineness and form beautiful feathery -tufts of brownish or olive-green color. They resemble, except in -their tawny color, the green alga /Cladophora/. - -The name is derived from Greek words meaning "outside" and "fruit," -the spores of the plants being borne on the branches. - -The species are determined by the arrangement of the spores, -according as they are in the pod-like branches, in groups, or in -cases on stalks. Since these differences are not perceptible to the -naked eye, it is impracticable to describe many species, or for the -amateur collector to try to separate them. - - -GENUS ^Ectocarpus^ - - ^E. littoralis.^ Filaments fine, in dense tufts, interwoven, six to - twelve inches long; pod linear in the substance of the branches; - color olive-green. This is the most common species of /Ectocarpus/, - and grows abundantly everywhere, appearing like large, fine, - dull-green plumes. (Plate IX.) [pg065] - - ^E. siliculosus.^ Tufts loosely entangled at the base, free and - feathery above, of indefinite length; spores in pod-like forms at - the ends of the branches. Common on the larger algae and on wharves. - - ^E. viridis.^ Tufts a little more loose and expanding than in /E. - siliculosus/; spores in pods at the base of the branches. (Plate - IX.) - - ^E. tomentosus.^ Fine filaments, densely interwoven into rope-like, - spongy masses, two to four inches long; yellowish-brown; pods on - stalks. Found in summer growing on /Fucus/. - - -ORDER =SPHACELARIACEAE= - - -GENUS ^Sphacelaria^ - - ^S. cirrhosa.^ Olive-brown; branched, feathery filaments, one - half of an inch to two inches long. Each branch ends with an - oblong, swollen cell containing a dark granular mass which gives - it a withered appearance. These cells can be seen with a strong - pocket-lens. It forms dense, globe-like tufts on /Fucus/. - - ^S. radicans.^ Filaments one half of an inch to one inch high; - branches few and hairy. It forms a dense, grass-like covering, of - indefinite extent, on the under side of muddy rocks. Found on the - New England coast. - - -GENUS ^Cladostephus^ - - ^C. verticillatus.^ Fronds bristle-like, dividing regularly; - covered with whorls of branchlets set close to the stems, each - whorl overlapping the previous one, giving the plant a spongy - appearance. (Plate IX.) - - -ORDER =RALFSIACEAE= - - -GENUS ^Ralfsia^ - -The species of this genus are brown, leathery, crustaceous expansions -of indefinite form, one inch to six inches in diameter, resembling -lichens. They appear on rocks in shallow, exposed pools. - - -ORDER =ENC[OE]LIACEAE= - - -GENUS ^Punctaria^ - -Dotted-weeds. Fronds pale olive-green, membranaceous, leaf-like, with -short stem; covered with spores which appear like dots. - - ^P. latifolia.^ Frond pale green, four to twelve inches long, one - inch to five inches wide, leaf-like, and tapering suddenly to a - short stalk; much [pg066] waved on margin; substance soft and - thin; dotted with spores. In the young plants fine hairs emerge - from the dots, but disappear later, and the fronds become darker - and more rigid. Found in summer on rocks and on other algae on the - Long Island and New England coasts. - - ^P. tenuissima.^ Fronds smaller and more slender than in /P. - latifolia/; thin and delicate. Found on eel-grass and /Chorda - filum/. - - ^P. plantaginea.^ Fronds dark brown, leathery, leaf-like, blunt or - wedge-shaped on top; dense clusters of hairs on the dots; six to - twelve inches long, one inch to one and a half inches wide. - - -GENUS ^Asperococcus^ - -This genus differs from /Punctaria/ in having a tubular instead of a -flat frond. (Plate IX.) - - ^A. echinatus.^ Resembles /Enteromorpha/ in being tubular; - compressed or inflated; obtuse at the apex; attenuated at the - base. It differs from /Enteromorpha/ in being olive in color, and - in being covered with small oblong dots of darker shade. When the - plant is young the dots are hairy. It grows in clusters, two to - eighteen inches long, one half of an inch to one inch wide. Common - along the New England coast. - - -GENUS ^Phyllitis^ - - ^P. fascia.^ Fronds light olive-green, leaf-like, three to six - inches long, one fourth to one half of an inch wide; margin entire, - slightly waved; contracted at base to short stalk; attached - by disk. This species grows in bunches on rocks and stones at - low-water mark, and is very common everywhere. (Plate X.) - - -ORDER =DESMARESTIACEAE= - -(/Named for M. Desmarest, a French naturalist/) - - -GENUS ^Desmarestia^ - - ^D. viridis.^ Filaments cylindrical, about as thick as a bristle; - branches opposite, in pairs, at intervals on the main stem. The - branches branch again and continue to be disposed in the same - manner. All are long and ultimately become very fine. The color is - olive-green, becoming verdigris-green when exposed to the air for - a short time or placed in fresh water. The species grows in deep - tide-pools and below low-water mark, forming fine, feathery plumes, - often a yard long, which give submerged rocks the appearance of a - luxuriant garden. (Plate X.) - - [Illustration: PLATE IX. Ectocarpus littoralis. Ectocarpus viridis. - Cladostephus verticillatus. Asperococcus bullosus.] - - [Illustration: PLATE X. Phyllitis fascia. Desmarestia viridis. - Desmarestia aculeata. Desmarestia ligulata.] - - ^D. aculeata^ ("spiny"). Fronds cylindrical at base, flattened - above; branches long and straight, arranged alternately, when young - beset with pencils of fine hairs, often one half of an inch long, - which, later, fall off, leaving alternate spines along the edges of - the flattened branches. It [pg067] grows from one foot to six - feet in length, below low-water mark, and is found washed ashore. - It is an attractive plant in the spring, but is brown and coarse - when old. Common everywhere. (Plate X.) - - ^D. ligulata.^ Fronds two to six feet long, pinnate, having a - flat main stem one half of an inch or more wide, with opposite - flat branches; leaflets arranged along the edges of the branches, - pointed at each end, and bordered with forward-pointing spines. It - is found washed ashore, in abundance, in California, but is not - found on the Atlantic coast. (Plate X.) - - -GENUS ^Arthrocladia^ - - ^A. villosa.^ Olive-brown filaments, resembling fine, knotted - threads, each knob having a whorl of delicate filaments. It grows - from six inches to three feet long, in deep water. It is rare, but - is occasionally found on the New England coast. - - -ORDER =DICTYOSIPHONACEAE= - - -GENUS ^Dictyosiphon^ - - ^D. f[oe]niculaceus.^ Fronds filiform, bristle-like, branching - into delicate, hair-like branches; yellowish-brown. It resembles - /Chordaria flagelliformis/, but is much finer. (Plate XI.) - - -ORDER =ELACHISTACEAE= - - -GENUS ^Elachista^ - -The plants of this genus are small, olive-colored, unbranched, -hair-like filaments, growing in dense, radiating tufts, one half -of an inch in height, on /Fucus/. They are interesting to the -microscopist, but not to the collector. - - -ORDER =CHORDARIACEAE= - -("/Cord-like/") - - -GENUS ^Chordaria^ - - ^C. flagelliformis^ ("whip-like"). Firm, leathery, somewhat - elastic, slimy strings, six to twenty-four inches long, and twice - as thick as a bristle; branches mostly undivided, short or long, - irregularly placed on the main axis, and curving inward at the - top of the frond; main axis not extending as far as the branches; - blackish in color; attached by a disk to stones and shells; - solitary or in bunches. It is common along the New England coast. - (Plate XI.) [pg068] - - -GENUS ^Mesogl[oe]a^ - - ^M. virescens.^ Soft, slimy filaments, with branches and - branchlets; olive-green. (Plate XI.) - - ^M. divaricata.^ Fronds two to twenty-four inches high; branching - irregularly, and generally without definite main axis; branches - flexuous, solid at first, later hollow; branchlets short and - wide-spreading. Common from Cape Cod southward; abundant in Long - Island Sound. (Plate XI.) - - -GENUS ^Leathesia^ - -This singular alga resembles a tuber and cannot be mistaken for any -other plant. Its fronds are gelatinous, fleshy balls, one half of an -inch to two inches in diameter, at first solid, afterward lobed and -hollow. It grows singly or in bunches on algae and on sand-covered -rocks, and is found in summer on every coast. The common species is -known as /L. difformis/ or /L. tuberiformis/. - - -GENUS ^Myrionema^ - -Minute algae which grow on other plants and which appear like dark -spots, or, at first, like stains, on /Ulva/, /Enteromorpha/, and -small red algae. These spots, which to the naked eye appear like -decay, show, under the microscope, a jelly-like substance full of -beaded filaments. - - -ORDER =LAMINARIACEAE= - -The plants of this order have large and coarse fronds (some -attaining an immense size), with stems, branching root-like -holdfasts, and expanded leaf-like laminae. They are leather-like, not -articulated, olive-green or brown in color, and sometimes yellow -and semi-transparent. They grow in deep water and are found washed -ashore. Sometimes small plants are found in deep tide-pools at -low-water mark. Some species are perennial. In these instances the -stems only survive, and the laminae are reproduced annually. The new -growth takes place at the apex of the stem. The old lamina is pushed -off, but is held on the summit of the new growth until the latter has -matured. - -[Illustration: PLATE XI. Dictyosiphon f[oe]niculaceus. Chordaria -flagelliformis. Mesogl[oe]a virescens. Mesogl[oe]a divaricata.] - -[Illustration: PLATE XII. Chorda filum. Agarum Turneri. Alaria -esculenta. Laminaria saccharina.] - -In the genus /Chorda/ the fronds are cylindrical; in /Agarum/ -[pg069] the laminae are perforated; in /Alaria/ there are wing-like -leaflets below the laminae. - -The /Laminariaceae/ and /Fucaceae/ are the seaweeds used in making -kelp. For this the algae are burned, and the ash is then separated -into its different mineral constituents and used for various -manufacturing purposes. - - -GENUS ^Chorda^ - - ^C. filum.^ Entire frond cylindrical, divided internally by - transverse septa; one fourth to one half of an inch in diameter, - tapering at each end; ordinarily one to twelve feet long, but - sometimes attaining a length of forty feet. When young the frond - is covered with fine, transparent hairs; later it is brown and - leather-like. The growth takes place at the base, just above the - disk-like holdfast, and at the apex it is constantly dying off. The - species is common on Northern shores, at and below low-water mark. - Often it is in masses which seem like meadows of waving grass under - water. Various small algae and many zooephytes are to be found on the - fronds. (Plate XII.) - - -GENUS ^Alaria^ - -This genus is readily distinguishable by the fact that it has -leaflets below the lamina. It is found north of Cape Cod. - - ^A. esculenta.^ Stem compressed, four to twelve inches long, one - fourth to one half of an inch wide, and running like a midrib - through the lamina; lamina one to ten feet long, two to ten inches - wide, frequently torn and ragged; margin wavy; leaflets three to - eight inches long and without midrib, growing on both sides of the - stem, below the lamina. The spores are produced in the leaflets in - the autumn. This is an edible alga and is used as food in Scotland - and Ireland, where it is called henware, badderlocks, murlins, and - so on. (Plate XII.) - - -GENUS ^Agarum^ - -The sea-colanders. - - ^A. Turneri.^ Stem two to twelve inches long, round below, - flattened above, and extending like a midrib through the lamina; - lamina one foot to four feet long, with holes over the whole - surface; margin wavy. The perforations in the lamina are produced - by conical hollow papillae which cover the young frond and which at - length burst, leaving a hole which enlarges as the plant expands. - This species is found from Cape Cod to Greenland. - - There are other species, which differ from this one in the size of - the perforations, the shape of the lamina, and the prominence of - the midrib. Harvey describes the plant as an arctic genus growing - ten to twelve feet long. (Plate XII.) [pg070] - - -GENUS ^Laminaria^ - -The plants of this genus are all large, varying from one foot to -twelve feet or more in length. They are of wide geographical range, -and are more numerous in species than any others of the order. They -are commonly known as oarweeds, tangle, devil's-aprons, sole-leather, -kelp, sea-furbelows, and so on. - - ^L. longicruris^ ("long-stalked"). Stem six to twelve feet long, - one to two inches thick, slender and solid at base, hollow and - inflated at the middle, contracted at the top; attached by a - strong, branching, root-like holdfast; color light brown. The - large, single, leaf-like lamina, usually shorter than the stem, is - five to twenty feet long, two to three feet broad, with much waved - and folded margin, outlined with two rows of depressed spots. The - spores form a band in the center of the blade. Found from Cape Cod - northward and on the Pacific coast. - - ^L. saccharina^, the sea-tangle. This species differs from /L. - longicruris/ in having a short, solid stem and narrow, ribbon-like - lamina. Stem three inches to four feet long; lamina three to - thirty feet long, six to eighteen inches wide, with central - band of depressed spots; margin much waved; color olive-green, - semi-transparent. It is named from the saccharine matter, called - /mannite/, which it contains. Found on northern shores of the - Atlantic and the Pacific oceans. (Plate XII.) - - ^L. digitata^ ("fingered"). Stem one to five feet long, thick, - round, and solid; lamina oval at base, leathery, smooth, brown, - deeply cleft into segments of unequal breadth. It is named from the - hand-like form of the lamina. This species is found in Long Island - Sound, but is not common south of Cape Cod. The stem is used by - fishermen for knife-handles. Pieces of it, placed on the blades - while green, contract in drying and become solid. (Plate XIII.) - -For the genera ^Macrocystis^, ^Nereocystis^, ^Lessonia^, and -^Thalassiophyllum^, see the Introduction, pages 35, 36. - - -ORDER =DICTYOTACEAE= - - -GENUS ^Dictyota^ - - ^D. fasciola.^ Fronds olive-brown, expanded, membranaceous, erect, - flat; many times forked narrow branches; grows in tufts six to ten - inches long, matted at the base. - - ^D. dichotoma.^ Same as /D. fasciola/, except that the divisions of - the forked frond are one eighth to one half of an inch wide. Found - in tide-pools in Southern waters. (Plate XIII.) - -[Illustration: PLATE XIII. Laminaria digitata. Dictyota dichotoma. -Taonia atomaria. Padina pavonia.] - -[Illustration: PLATE XIV. Haliseris polypodioides. Cutleria -multifida. Fucus vesiculosus.] - - -GENUS ^Zonaria^ - - ^Z. lobata.^ Thallus flat, fan-shaped, but not so rounded as - in /Padina pavonia/, twelve or more inches in height, cleft - irregularly into many [pg071] narrow lobes, the clefts - extending nearly or quite to the base; olive-green, with concentric - zones of darker color; edges thin and bordered with a dark line. - Found in southern California and in tropical and subtropical seas. - - -GENUS ^Taonia^ - - ^T. atomaria.^ Spreading, fan-shaped frond; clefts irregular and - not extending to the basal stem; spores arranged in dark wavy - lines and spots on the frond, giving it a mottled appearance and - beautiful gradation of color. Found in tropical seas. (Plate XIII.) - - -GENUS ^Padina^ - - ^P. pavonia^, the peacock's-tail. Frond broadly fan-shaped; - substance between membranaceous and leathery; powdery on the - outer surface; deeply and variously cleft or entire; several - laminae emanating from a stalk-like base; each lamina fan-shaped; - concentric lines numerous; variegated in zones. This beautiful alga - is always regarded as a prize. It is found on stones at low-water - mark, and is not uncommon south of Charleston, South Carolina, but - is more luxuriant in tropical seas. (Plate XIII.) - - -GENUS ^Haliseris^ - -The sea-endive. - - ^H. polypodioides.^ Fronds flat, forked, notched on lower part; - divisions about one quarter of an inch wide; distinct midrib; - olive-green; grows in tufts. It is found in North and South - Carolina, and is abundant on the Florida Keys. (Plate XIV.) - - -ORDER =CUTLERIACEAE= - - -GENUS ^Cutleria^ - - ^C. multifida.^ Frond erect, flat; branches in a forking manner; - ultimate branches fine and short, and with branchlets on the tips. - This species resembles /Taonia/. It is found in Southern waters. - (Plate XIV.) - - -ORDER =FUCACEAE= - - -GENUS ^Himanthalia^ - - ^H. lorea^, the sea-thong. A cup-shaped base, from the center of - which arises a flat, strap-like frond one fourth to one half of an - inch wide and two to twenty feet long, branching dichotomously (or - by forking), and dotted with pits, or conceptacles, in which the - spores are formed. Found in the extreme North. [pg072] - - -GENUS ^Fucus^ - -The rockweeds. The plants of this genus grow in thick bunches, and -are found in great abundance between tide-marks. The plants are -attached by sucker-like disks to the rocks, from which they hang like -fringe when the tide recedes; when it rises they float and sway in -the water in beautiful bouquet-like forms. In color they are brown or -olive-green, in texture thick and leathery, but they sometimes expand -into thin membranes. They are many times forked in the same plane, -which produces a flat thallus. They often have a distinct midrib. The -air-vessels, whose function it is to float the plant, are disposed -along the midrib, usually in pairs. - -The species are named according to the divisions of the frond, -and the disposition, or presence, of the air-bladders and the -/conceptacles/, or spore-chambers. - -The conceptacles congregate in particular portions of the frond and -give its surface a roughness which is very perceptible; such portions -are then known as the /receptacles/. In /Fucus/ this usually occurs -on the bulbous extremities of the branches. Under the microscope a -section of one of these little pointed spots shows a spherical cavity -filled with a beautiful arrangement of /paraphyses/, or threads, -some of which hold spores, while others protrude through a small -opening in the outer membrane. Conceptacles are peculiar to the -order =Fucaceae=. In them spore-production is carried on in a manner -as complicated as is the formation of seeds in flowering plants. -Although rockweeds are such a conspicuous feature of sea-shore -vegetation, two species only, /Fucus vesiculosus/ and /Ascophyllum -nodosum/ (formerly called /Fucus nodosus/), are common on the -Atlantic coast, and these do not occur south of New York, owing to -the fact that a long stretch of sand-beach extends beyond that point. - - ^F. vesiculosus.^ Midrib distinct through all the forked branches; - margin entire, often wavy; air-vessels spherical or oblong, usually - in pairs along the midrib; receptacles on terminal branches, which - are swollen and filled with gelatinous matter, heart-shaped or - forked, in oblong or pointed divisions; frond tough and leathery, - often two feet long. (Plate XIV.) - -[Illustration: PLATE XV. Fucus serratus. Fucus ceranoides. -Ascophyllum nodosum.] - -[Illustration: PLATE XVI. Phyllospora Menziesii. Halidrys osmunda. -Sargassum vulgare.] - - ^F. serratus.^ Frond distinctly toothed or serrated along the - margin; midrib conspicuous through the main axis and forked - branchings; no air-vessels. This species is rare on the Atlantic - coast. (Plate XV.) - - ^F. furcatus.^ Frond narrow, tough, without air-vessels; regular - forked branching; midrib distinct below, inconspicuous above; - receptacles long, narrow, not inflated. Found from Boston northward. - - ^F. ceranoides.^ Frond flat, rather membranaceous, or less leathery - than in the preceding species; repeatedly forked; midrib not - running through every division; no air-vessels. (Plate XV.) - - -GENUS ^Ascophyllum^ - - ^A. nodosum.^ This species, formerly called /Fucus nodosus/, is - next to /Fucus vesiculosus/ the most common rockweed. Frond one to - five feet long, dark brown, strap-like, leathery; width of main - stems one fourth of an inch or more, and uniform throughout; large, - single, oblong air-vessels distend the frond at intervals. Branches - of various length emerge from the sides of the main stem. Ovoid or - ellipsoidal branchlets or receptacles, single or in groups, occur - at intervals along the sides of both stem and branches. These fall - off after a time and are found in quantities in tide-pools. (Plate - XV.) - - -GENUS ^Phyllospora^ - - ^P. Menziesii.^ Branching holdfast; short stem which immediately - divides into strap-like branches; branches edged with leaves - varying in length, rounded at top, narrow, stalked at base; leaves - placed at intervals, or crowded together, and interspersed with - air-vessels which are often tipped with leaflets; stems expand at - summit into leaf-like laminae and are edged with leaflets at the - base; plant often one hundred and twenty feet or more in length; - tough and leathery in substance. Very common on the California - coast. (Plate XVI.) - - -GENUS ^Cystoseira^ - - ^C. expansa.^ Frond long, slender, repeatedly branched; air-vessels - ellipsoidal and "chained" together in the lower half of the - branches. The plant grows in deep water, ad shows iridescent colors - when seen through the water. It is found on the California coast. - - -GENUS ^Halidrys^ - - ^H. osmunda^, the sea-oak. Frond flat, alternately toothed - or indented below; branched apex, bearing air-vessels like - long-stalked pods; substance leathery. Found on the coast of - southern California. (Plate XVI.) - - -GENUS ^Sargassum^ - -^Sargassum^ is distinguished by its differentiation into stem and -leaf, resembling in outward appearance the higher plants. It [pg074] -is a tropical and subtropical genus, and has one hundred and fifty -species. Two of these, /S. vulgare/ and /S. Montagnei/, are found as -far north as Cape Cod. See Introduction, page 34. - - ^S. vulgare.^ Stems cylindrical; branches alternate; leaves long, - narrow, toothed, with short stalk and midrib; minute dark spots - on its surface; air-vessels small balls resembling berries set on - stalks and usually tipped with a long point; receptacles small, - twig-like forms in the axils of the leaves; color olive-brown; - plant one foot to three or more feet long. Common in Long Island - Sound. (Plate XVI.) - - ^S. Montagnei.^ This species resembles /S. vulgare/, but is more - slender in all its parts, and the receptacles are more elongated. - From south of Cape Cod. - - ^S. bacciferum.^ Particular interest attaches to this species from - the fact that it is the one which forms the floating vegetation - of the Sargasso Sea. It grows attached on the Florida Keys and in - the West Indies. Specimens are sometimes carried by the currents - northward, and are found washed ashore. It differs from /S. - vulgare/ in the leaves, which are thicker, more attenuated, and - sharply toothed, and in having a greater number of air-vessels. - A branch of this species brought from the Sargasso Sea had - air-vessels so numerous and closely set that it resembled a bunch - of small grapes. - - - - -III - -RED SEAWEEDS - -(RHODOPHYCEAE OR FLORIDEAE) - - -TABLE SHOWING THE CLASSIFICATION OF THE RED SEAWEEDS DESCRIBED IN -THIS CHAPTER - - Class =ALGAE= - - Subclass =Rhodophyceae or Florideae= (/Red Seaweeds/) - - Order =NEMALIONACEAE= - - Suborders Genera Species - - ~HELMINTHOCLADIEAE~ ^Nemalion^ ^N. multifidum^ - ^Liagora^ - - ~CHAETANGIEAE~ ^Scinaia^ ^S. furcellata^ - - ~GELIDIEAE~ ^Gelidium^ ^G. corneum^ - - Order =GIGARTINACEAE= - - ^Chondrus^ ^C. crispus^ - ^Gigartina^ ^G. mamillosa^ - ^G. radula^ - ^G. spinosa^ - ^G. microphylla^ - ^Phyllophora^ ^P. membranifolia^ - ^P. Brodiaei^ - ^Sternogramme^ ^S. interrupta^ - ^Gymnogongrus^ ^G. Norvegicus^ - ^Ahnfeldtia^ ^A. plicata^ - ^Callophyllis^ ^C. variegata^ - ^C. laciniata^ - ^Iridaea^ - - Suborders Genera Species - - ~RHODOPHYLLIDEAE~ ^Cystoclonium^ ^C. purpurascens^ - ^C. cirrhosa^ - ^Euthora^ ^E. cristata^ - ^Rhodophyllis^ ^R. veprecula^ - ^Rhabdonia^ ^R. tenera^ - ^R. Coulteri^ - ^Eucheuma^ ^E. isiforme^ - - Order =RHODYMENIACEAE= - - ~SPHAEROCOCCEAE~ ^Gracilaria^ ^G. multipartita^ - ^Hypnea^ ^H. musciformis^ - - ~RHODYMENIEAE~ ^Rhodymenia^ ^R. palmata^ - ^Lomentaria^ ^L. Baileyana^ - ^Champia^ ^C. parvula^ - ^Chylocladia^ ^C. articulata^ - ^Plocamium^ ^P. coccineum^ - - ~DELESSERIEAE~ ^Nitophyllum^ ^N. laceratum^ - ^N. Ruprechteanum^ - ^N. punctatum^ - ^Grinnellia^ ^G. Americana^ - ^Delesseria^ ^D. sinuosa^ - ^D. alata^ - ^D. Leprieurii^ - - ~RHODOMELEAE~ ^Polysiphonia^ ^P. fastigiata^ - ^P. nigrescens^ - ^P. parasitica^ - ^P. dendroidea^ - ^P. Baileyi^ - ^P. Harveyi^ - ^P. Olneyi^ - ^P. fibrillosa^ - ^P. violacea^ - ^P. urceolata^ - Var. ^formosa^ - ^P. variegata^ - ^P. Woodii^ - - ^Laurencia^ ^L. pinnatifida^ - ^Dasya^ ^D. elegans^ - ^D. plumosa^ - - ^Bostrychia^ ^B. rivularis^ - ^Rhodomela^ ^R. subfusca^ - ^R. Rochei^ - ^R. larix^ - ^R. floccosa^ - ^Chondria^ ^C. dasyphylla^ - ^C. tenuissima^ - ^C. striolata^ - - Suborders Genera Species - - ~CERAMIEAE~ ^Callithamnion^ ^C. americanum^ - ^C. Pylaisaei^ - ^C. Baileyi^ - ^C. seirospermum^ - ^C. byssoideum^ - ^C. floccosum^ - ^Griffithsia^ ^G. Bornetiana^ - ^Ptilota^ ^P. serrata^ - ^P. elegans^ - ^P. densa^ - ^P. hypnoides^ - ^Spyridia^ ^S. filamentosa^ - - ^Ceramium^ ^C. rubrum^ - Var. ^proliferum^ - Var. ^secundatum^ - ^C. strictum^ - ^C. diaphanum^ - ^C. fastigiatum^ - ^C. tenuissimum^ - Var. ^patentissimum^ - ^Microcladia^ ^M. Coulteri^ - ^M. borealis^ - - Order =CRYPTONEMIACEAE= - - ~GLOIOSIPHONIEAE~ ^Gloiosiphonia^ ^G. capillaris^ - - ~GRATELOUPIEAE~ ^Halymenia^ ^H. ligulata^ - ^Grateloupia^ ^G. Cutleria^ - ^Prionitis^ ^P. lanceolata^ - ^P. Andersonii^ - - ~DUMONTIEAE~ ^Pikea^ ^P. Californica^ - ^Halosaccion^ ^H. ramentaceum^ - - ~RHIZOPHYLLIDEAE~ ^Polyides^ ^P. rotundus^ - - ~SQUAMARIEAE~ ^Peyssonnelia^ ^P. Dubyi^ - ^Petrocelis^ ^P. cruenta^ - ^Hildenbrandtia^ ^H. rosea^ - - ~CORALLINEAE~ ^Corallina^ ^C. officinalis^ - ^Melobesia^ - - Order =BANGIACEAE= - - ^Bangia^ ^B. fusco-purpurea^ - ^Porphyra^ ^P. vulgaris^ - ^P. laciniata^ - -[pg079] - - - - -RED SEAWEEDS - - -In =Rhodophyceae=, known also as =Florideae= and =Rhodospermeae=, -algae attain their highest development. This is marked by the mode -of reproduction, which, more nearly than in the other subclasses, -resembles that of flowering plants. The fronds, however, are not as -large and do not as closely resemble stem and leaf as do some species -of the brown algae. - -The species of this subclass are very numerous, and the variety in -their fronds, their delicate texture, and their colors, which vary -from pink to purple, make them the most attractive of the seaweeds. -They grow mostly in deep water, but are often found washed ashore, -and many grow just below low-water mark and on the shady side of -tide-pools. - -In the simplest species the frond consists of branched cell-rows. -In some of these the filaments are so fine that a pocket-lens is -required to determine the differences in branching and fully to -appreciate the beauty of the plant (/Callithamnion/). Some have a -cell-surface. In /Delesseria/ the membrane assumes the outline of a -foliage-leaf. /Dasya/, which is an abundant variety, is especially -beautiful in its feather-like appearance. The corallines are singular -in that they are incrusted with lime and resemble corals. - - -ORDER =NEMALIONACEAE= - - -SUBORDER ~HELMINTHOCLADIEAE~ - - -GENUS ^Nemalion^ - -The threadweeds. - - ^N. multifidum.^ Frond six to twelve inches long, cylindrical, - solid, cord-like, elastic, tough, shiny, very gelatinous; branches - repeatedly in [pg080] a wide-forking manner; sometimes a branch - will divide into several parts at the same point; color dark brown - or purple. It is found, in summer only, from Long Island Sound - northward, growing on smooth rocks which are exposed to the action - of the waves. - - -GENUS ^Liagora^ - -Fronds filamentous; branching regularly in a forking manner to the -very top, forming thick bunches; slightly incrusted with lime, yet -somewhat viscid. It is found in Florida and California, and abounds -in tropical waters. - - -SUBORDER ~CHAETANGIEAE~ - - -GENUS ^Scinaia^ - - ^S. furcellata.^ Frond cylindrical, one eighth of an inch in - diameter, tapering at base, sometimes constricted at intervals, - regularly and several times forked, ending in short divisions; - branches of same length, giving a level top; two to four inches - high; lake-red. When pressed the axis is visible, giving the - appearance of a flat frond with a midrib. This species is found - in summer only, washed ashore from Cape Cod southward and on the - California coast. It is not common. (Plate XVII.) - - -SUBORDER ~GELIDIEAE~ - - -GENUS ^Gelidium^ - - ^G. corneum.^ Frond flat and horny, one inch to four inches high, - narrow, erect, branched several times in the same plane; ultimate - branchlets club-shaped, or swollen at the tips with masses of - spores; color purple-red. It grows in tufts on mud-covered rocks, - and on algae at low-water mark. The typical form is found in Florida - and on the Pacific coast. Smaller plants are found all along the - Atlantic shore. It is an extremely variable plant, and is often - difficult to distinguish on this account. (Plate XVII.) - -[Illustration: PLATE XVII. Scinaia furcellata. Gelidium corneum. -Gelidium Coulteri. Chondrus crispus.] - - -ORDER =GIGARTINACEAE= - - -GENUS ^Chondrus^ - -Carrageen or Irish moss. - - ^C. crispus.^ Frond begins with flattened stem, which divides and - subdivides many times in a broad-forked, fan-like manner; varies - greatly in length and breadth of divisions, also in size and color, - according to conditions of its habitation. In shallow tide-pools - it is pale and [pg081] stunted; but under the shelter of - rocks, in deep water, it grows in dense masses and is a dark - purplish-red or reddish-green. Often it appears iridescent when - seen through the water, with the sun shining on it. It is firm and - leathery in substance. It is an edible alga, and was formerly very - generally used for culinary purposes. At Hingham, Massachusetts, - large quantities are gathered as an article of commerce. It is a - beautiful and very common plant found from New York northward. - (Plate XVII.) - - -GENUS ^Gigartina^ - -Of the species of this genus but one is found on the eastern coast; -on the Pacific coast there are several, and they are large and -conspicuous. - -[Illustration: PLATE XVIII. Gigartina mamillosa. Gigartina radula. -Gigartina spinosa. Gigartina microphylla.] - - ^G. mamillosa.^ Frond three to six inches high, one inch to two - inches broad, flat, leathery, gelatinous; forking near the base, - then dividing and subdividing in the same plane; segments more or - less wedge-shaped and with a tendency to roll inward; covered with - numerous small nipple-like protuberances which contain the spores. - These projections distinguish this genus from /Chondrus/, which it - otherwise resembles, and with which it grows. The color is dark - purple. It is found from Boston northward. (Plate XVIII.) - - ^G. radula.^ Frond flat and thick; rising from a short stem - and widening to several inches; sometimes tapering to the top, - sometimes blunt or divided, sometimes cleft on the sides, but - usually simple; covered with wart-like projections; color dark, - livid red. It is found on the Pacific coast at all seasons, growing - on rocks between tide-marks. Large specimens are one foot to three - feet long and six to ten inches wide. (Plate XVIII.) - - ^G. spinosa^ ("thorny"). Frond thick, leathery; surface rough and - spiny; form variable, the divisions sometimes emanating from a - broad, flattened base, or again branching from a main axis; all - covered with the protruding processes peculiar to the genus; color - dark red, brown, or purple. It is found on the California coast. - (Plate XVIII.) - - ^G. microphylla^ ("small-leaved"). Plant rises from short, flat - stem, and rapidly expands into a flat, wide, thin frond which is - simple or divided into two or three segments, each of which tapers - into a long, pointed apex; thickly covered with long, slender - spines, and on its edges bearing small, thin leaflets; color - brownish-red. It is abundant on the California coast. (Plate XVIII.) - - -GENUS ^Phyllophora^ - -Leafweed. Fronds cylindrical; branched stalks which expand into -rigid, membranaceous, simple or cleft, wedge-shaped laminae; laminae -bear leaflets on their edges or on their surface; spores in masses -form projections on the surface, or are on stalks at the summit; -color dark red. Found washed ashore from New York northward. [pg082] - - ^P. membranifolia.^ Several stems rise from same disk; branches - expand into wedge-shaped, cleft or forked laminae; lobes bear on the - summit other laminae or leaflets divided in the same manner. - - ^P. Brodiaei.^ Stem less branched and leaf-expansions broader and - larger than in /P. membranifolia/; laminae wedge-shaped and deeply - lobed. (Plate XIX.) - - -GENUS ^Sternogramme^ - - ^S. interrupta.^ Frond a thin membrane repeatedly forked, widely - spreading, divisions one fourth to one half of an inch wide; - fertile plants have the spores arranged in an interrupted line - through the center of the segments resembling a midrib; frond two - to eight inches high; bright red. It is found on the California - coast. The illustration shows a plant on which the hydroid - /Sertularia pumila/ is growing. (Plate XIX.) - - -GENUS ^Gymnogongrus^ - - ^G. Norvegicus.^ Frond two to four inches high, thin but leathery - in substance, flat, narrow, divided in a regular forking manner; - spreading ends of terminal forks obtuse; axils rounded; spores form - spherical masses in the upper segments, and project on both sides - like hemispheres. It resembles a simple form of /Chondrus crispus/, - but is more delicate. The color is red or purple. This species is - found in deep tide-pools from New York northward. (Plate XIX.) - - -GENUS ^Ahnfeldtia^ - - ^A. plicata.^ Frond coarse, stem-like filaments, stiff, wiry, - irregularly and profusely branched; sometimes regularly forked and - upper segments equal; entangled; six to eight inches long; tufts - several inches in diameter; dark purple or black. Specimens long - exposed on the beach are faded to white. It is very common from New - York northward. (Plate XIX.) - - -GENUS ^Callophyllis^ - - ^C. variegata.^ Deeply cleft, wide-spreading, flat, membranaceous - frond; all parts notched more or less angularly; color dark to - bright red; spores form hemispherical warts on surface. Some - varieties differ from this one in having long and narrow, and - others in having short and broad segments. It is a beautiful and - common alga on the Pacific coast, resembling /Euthora/ of the - eastern coast. (Plate XX.) - - ^C. laciniata.^ Frond deeply cleft; segments wedge-shaped. It is - found on the Pacific coast. (Plate XX.) - -[Illustration: PLATE XIX. Phyllophora Brodiaei. Sternogramme -interrupta. Gymnogongrus Norvegicus. Ahnfeldtia plicata.] - -[Illustration: PLATE XX. Callophyllis variegata. Callophyllis -laciniata. Iridaea. Cystoclonium cirrhosa.] - - -GENUS ^Iridaea^ - -Frond rises from stalk and widens into a flat, thick, leathery, oval -expansion, one to two feet long, and one to three inches broad; -[pg083] simple or lobed; surface sometimes roughened by collections -of spores in dots; dark red, often glittering in the water with blue -and purple tints. It is found on the Pacific coast. (Plate XX.) - - -SUBORDER ~RHODOPHYLLIDEAE~ - - -GENUS ^Cystoclonium^ - - ^C. purpurascens.^ The translucent, fleshy, juicy main stem, one - eighth of an inch or less in diameter, runs through the whole - plant; irregularly branched all around main stem; branches again - branch in same manner; branches attenuated at the base, and taper - to a long point; smaller branches distended in places by spores - into bladder-like swellings, hence the name; color rose-red to - dark purple; plants exposed on the beach often faded to orange - and white; six to eighteen inches long. It grows on rocks between - tide-marks as well as in deep water. With the exception of - /Ceramium rubrum/, this is the most common red alga on the eastern - coast from New York northward. It differs from /Rhabdonia/ in - having bladdery branches; otherwise it is easily mistaken for it. - - ^C. cirrhosa.^ Ends of branches terminate in spirals like tendrils; - otherwise identical with /C. purpurascens/. (Plate XX.) - - -GENUS ^Euthora^ - - ^E. cristata.^ Frond one inch to five inches high, membranaceous, - broadly spreading; divisions wide and numerous, ultimately becoming - fine like minute branchlets, each one of which, under a glass, - shows a notch in the tip. This beautiful, bright-red alga is found - in abundance north of Cape Cod. It differs from /Delesseria alata/ - in having no midrib or veins. It grows in deep water on stones, - shells, and algae. (Plate XXI.) - - -GENUS ^Rhodophyllis^ - -("/Rosy leaf/") - - ^R. veprecula.^ Frond two to five inches long, one fourth of an - inch to one and one half inches broad, membranaceous, forked; - margin covered with leaflets which are in turn edged with minute - branchlets; color deep red. It is found on the northern New England - coast. (Plate XXI.) - - -GENUS ^Rhabdonia^ - -("/A wand/") - - ^R. tenera.^ Frond six to eighteen inches long, cylindrical, - fleshy, translucent, juicy; irregularly and profusely branched, - branches longest at the base, erect, tapering at both ends, - numerous branchlets; sometimes the main stem runs through - the plant, sometimes it is lost in the [pg084] branching; - spore-masses sometimes form knotty bunches on the side of - branches. It resembles a large /Cystoclonium purpurascens/. It is - characteristic of Long Island Sound, and is not found north of - Cape Cod, but common from there southward along the whole Atlantic - coast. (Plate XXI.) - - ^R. Coulteri.^ This species is common on the Pacific coast, and - differs from /R. tenera/ in having a more pronounced leading stem, - and branches shorter and crowded at the top of the frond. - - -GENUS ^Eucheuma^ - - ^E. isiforme.^ Frond grows in tufts a foot or more in diameter; - stems branch in all directions from a central point, and taper - gradually to the end; secondary branches spread to all sides; - all branches swollen at intervals and armed with several spines - spreading from a conical base; color dark red, becoming on exposure - orange or yellow, and at length semi-transparent and horn-like; - substance firmly cartilaginous. Abundant at Key West. - - -ORDER =RHODYMENIACEAE= - - -SUBORDER ~SPHAEROCOCCEAE~ - - -GENUS ^Gracilaria^ - - ^G. multipartita^ ("many times divided"). Frond four to twelve - inches long; starting from a short, cylindrical stem, it flattens - and broadens as it rises, dividing in an irregular, forking manner, - or cleft into palmate segments which broaden as they rise, and - which divide in the same manner; often cleft or branched on the - edges; conical spore-masses scattered over the frond during July - and August; dingy purple in color. The plant is variable and - sometimes is difficult to determine. It is common from Cape Cod - southward. A narrow variety is most abundant in Long Island Sound. - In Florida and on the California coast there are broad varieties - which may be mistaken for /Rhodymenia/. (Plate XXI.) - - -GENUS ^Hypnea^ - - ^H. musciformis^ ("moss-like"). Frond six to twelve inches long; - main stem running through, thick below and tapering to the size of - a bristle; much and irregularly branched, especially at the base; - branches wide-spreading in every direction, and longest at the - base; branches branch again in the same manner; all parts beset - with short, horizontal spines; color purplish-red. A characteristic - feature, by which the plant can easily be distinguished, is that - the ends of the long branches are naked and are turned over like a - hook, or nearly twisted. It is found washed ashore, often in large, - intricately twisted tufts, from Cape Cod southward and on the - Pacific coast. - -[Illustration: PLATE XXI. Euthora cristata. Rhodophyllis veprecula. -Rhabdonia tenera. Gracilaria multipartita.] - -[Illustration: PLATE XXII. Rhodymenia palmata. Rhodymenia palmata. -Lomentaria Baileyana. Chylocladia articulata.] - - -SUBORDER ~RHODYMENIEAE~ - - -GENUS ^Rhodymenia^ - -("/Red membrane/") - - ^R. palmata^ ("hand-shaped"). The plant commonly known as dulse. - Frond rises from a disk in a short cylindrical stem which spreads - into a thin, broad, fan-shaped membrane six to twelve inches long - and four to eight inches wide at the top; deeply and irregularly - cleft into many wedge-shaped segments; margin usually entire, but - often with leaflets; ends of segments indented, showing where - divisions will ultimately occur; color dark purplish-red. It grows - on rocks and on algae below low-water mark, and is common on the New - England and California coasts. This is an edible alga, and, like - /Chondrus crispus/, is an article of food in seaports. (Plate XXII.) - - -GENUS ^Lomentaria^ - - ^L. Baileyana.^ Fronds two to five inches high; grows in tufts; - filaments tubular, irregularly branched; branchlets often all on - one side; branches and branchlets curved or arched, and tapered at - both ends; color brownish-red. It is found washed ashore from Cape - Cod southward. (Plate XXII.) - - -GENUS ^Champia^ - - ^C. parvula.^ Frond two to six inches long, irregularly branched; - grows in tufts; filaments hollow and constricted, so that they - appear somewhat like a string of beads; color brownish-purple. It - is found washed ashore from Cape Cod southward. (Plate XXIII.) - - -GENUS ^Chylocladia^ - - ^C. articulata.^ Frond filamentous, three to twelve inches long, - hollow, constricted at intervals; branches emanate from constricted - joints; has the appearance of a series of pink, delicate, oval - sacs. (Plate XXII.) - - -GENUS ^Plocamium^ - - ^P. coccineum^ ("scarlet"). Frond a flat, semi-cartilaginous main - stem one eighth of an inch, or less, wide, three to eight inches - long, with alternate branches of unequal length emanating from the - edges; branches have alternate branchlets arranged in groups of - three or four in a row; branchlets have pinnulae on the upper side, - like the teeth of a comb (this peculiarity in branching makes the - genus easy to identify); color dark lake-red. It is not found on - the eastern coast, but is plentiful in California. (Plate XXIII.) - - -SUBORDER ~DELESSERIEAE~ - - -GENUS ^Nitophyllum^ - - ^N. laceratum.^ Frond expands from narrow base and divides almost - at once into long, narrow, strap-shaped segments; minute leaflets, - showing [pg086] a dot or spore-cluster, occur at intervals on the - margin; plant six to eight inches long; thin and silky in texture. - Abundant on the California coast. (Plate XXIII.) - - ^N. Ruprechteanum.^ Frond one foot to two feet long, spreading - from narrow base and dividing by forking into deep-cut, broad, - strap-like lobes; top divisions rounded; traversed lengthwise by - parallel veins; margin of the older parts bordered with a narrow - frill of thin ruffled membrane which sometimes extends also over - parts of the surface of the frond; substance somewhat rigid; color - dark red to purple. It is found on the California coast. (Plate - XXIV.) - - ^N. punctatum.^ Frond six to twenty inches long and of the same - width, dividing in a forking manner; crowded at top; when in fruit, - covered with dark dots; substance thin and silky; color rose-pink. - It is found on the California coast. (Plate XXIV.) - - -GENUS ^Grinnellia^ - -(/Named for Mr. Henry Grinnell of New York/) - - ^G. Americana.^ Frond a delicate membrane, rose-red or purplish in - color, leaf-shaped, four to eight inches long, one inch to four - inches wide, tapering at both ends; margin entire, but much waved; - a line of darker color through the center resembles a midrib; - masses of spores form dots or specks irregularly over the whole - surface; grows from a disk and short slender stem in bunches on - shells and stones in deep water. It is found washed ashore from - Cape Cod southward, and is luxuriant in New York Bay, where it can - be found at any season, but is in perfection in August. (Plate - XXIV.) - - -GENUS ^Delesseria^ - - ^D. sinuosa.^ Delicate, leaf-like membrane, with midrib and veins, - much indented and resembling in general outline an oak-leaf; four - to eight inches long, two to four inches broad; short stem; color - dark red, often flecked with green. It grows in bunches in deep - water, and is easily distinguished, since it is the only alga - having a midrib and veins, and resembling the leaf of a tree. It is - found washed ashore from Cape Cod northward. (Plate XXIV.) - - ^D. alata^ ("winged"). Frond rises from short stem, which flattens - and divides irregularly into many branches and appears like a - midrib, all bordered with narrow membrane one eighth of an inch to - one inch wide; frond two to four inches long; color light red or - pink. It is found on the shore from Cape Cod northward. (Plate XXV.) - - ^D. Leprieurii.^ Frond one inch to two inches long, very narrow, - with delicate midrib, forked, constricted at intervals; branches - start from constricted points; thin and delicate; color purple. - It is found in tidal rivers near New York, and is common on the - southern coast. (Plate XXV.) - -[Illustration: PLATE XXIII. Champia parvula. Champia parvula, -magnified. Plocamium coccineum. Nitophyllum laceratum.] - -[Illustration: PLATE XXIV. Nitophyllum Ruprechteanum. Nitophyllum -punctatum. Grinnellia americana. Delesseria sinuosa.] - -[Illustration: PLATE XXV. Delesseria alata. Delesseria Leprieurii. -Polysiphonia fastigiata (on Ascophyllum). Polysiphonia parasitica.] - -[Illustration: PLATE XXVI. Polysiphonia dendroidea. Polysiphonia -dendroidea, a piece magnified. Polysiphonia Harveyi. Polysiphonia -Harveyi, a piece magnified.] - - -SUBORDER ~RHODOMELEAE~ - -The genera included in this suborder are easily distinguished when in -fruit by the spore-cases, or cystocarps, which appear [pg087] -like little balls, either adherent to the branches, or raised on -short stalks. It is the largest group, and contains many of the most -beautiful of the red algae. - - -GENUS ^Polysiphonia^ - -("/Many tubes/") - -A filament of ^Polysiphonia^ appears, when seen under the microscope, -like a bundle of filaments made up of a central tube, or axis, -surrounded by a number of other tubes. It is by the number of these -parts, called siphons, which vary in number from four to twenty, that -the species is determined. In some plants the siphons are surrounded -by a layer of cells, called corticating or bark cells, which give -the filaments a solid, uniform appearance. In others the siphons are -naked, and the filaments then seem striped or banded with color. It -is difficult, without a microscope, to be sure of the classification. -There are, however, other characteristics which separate many of the -species, and some of these are described below. Two hundred species -of /Polysiphonia/ have been named by algologists. The plants are -plentiful on all shores, especially in warm, shallow waters. Some -species are perennial, but most of them are annuals and disappear in -winter. - - ^P. fastigiata.^ This species grows on /Ascophyllum nodosum/ in - a globular tuft, and appears like a dark-brown ball, one inch - to three inches in diameter. The frond is a dense mass of rigid - filaments branching many times in a forking manner and at broad - angles. The ends are of nearly equal length, giving the plant - a spherical shape. It is common from New York northward at all - seasons, and is easily recognized by its general form and place of - growth. Egg-shaped cystocarps, or spore-cases, occur in the ends of - the terminal filaments. (Plate XXV.) - - ^P. nigrescens.^ Frond three to twelve inches long, rigid below, - soft above; main stem thick as a bristle, but not always easy to - distinguish; branches alternate and densely branched at the ends; - siphons twelve to sixteen in number; filaments banded; color black - or very dark brown. (Plate XXVII.) - - ^P. parasitica.^ Frond one inch to three inches long; branched in - a pinnate or feather-like manner; filaments flat; all branches - and branchlets emanating from the edges and on the same plane, - giving a flat frond; color reddish-brown; resembles a fine /Ptilota - plumosa/; cystocarps on short stalks. It is found on the California - coast. (Plate XXV.) - - ^P. dendroidea.^ This is a variety of the species /P. parasitica/. - Frond four to five inches long; main branches placed at irregular - intervals, but the secondary branches at regular intervals and - alternate; branches [pg088] set at acute angles, giving the plant - a slender appearance; color black or dark brown. It is common on - the California coast. (Plate XXVI.) - - ^P. Baileyi.^ Frond three to six inches high, flat; branches - emanate from edges of the flat stems; main branches wide-spreading - and irregularly placed, secondary branches regular and alternate; - branchlets one eighth to one half of an inch long, covered on the - edges and around the top with incurved ramuli; branchlets broken - off near the base of the branches in mature plants; branchlets - usually uniform in length, but occasionally one is longer and - branches like the primary stem; color black. Common on the - California coast. - - ^P. Harveyi.^ Frond two to six inches high; grows in globose tufts, - and has a bushy aspect; branches stiff and wide-spreading; stems - and branches beset with simple or branched spine-like branchlets; - color dark brown, or black when dry; does not collapse when taken - from the water; cystocarps on short stalks; siphons four in number. - It grows on eel-grass and algae, and is common in Long Island Sound - and northward. Called locally /niggerhair/. (Plate XXVI.) - - ^P. Olneyi^ (dough-balls). Fronds two to five inches high, densely - tufted; soft filaments of hair-like fineness, much branched, and - spreading; when in fruit covered with tiny balls or cystocarps; - siphons four in number. It is common from Cape Cod to New York. - - ^P. fibrillosa.^ Frond four to ten inches high, rather robust - below; main stem quickly lost in a number of prominent stems and - spreading branches; irregularly and profusely branched, becoming - ultimately very fine; numerous branchlets covered with colorless - fibrils in hairy tufts, which give it a misty appearance; fibrils - so delicate that they do not show well in dried specimens, but a - distinct feature by which to recognize the species in the young - plant; color light to dark brown; cystocarps adherent to branchlets - or on short stalks; siphons four in number; main branches only - corticated. It is common in summer on stones and on eel-grass, at - low-water mark, from Cape Cod to New York. (Plate XXVII.) - - ^P. violacea.^ Fronds six to twenty-four inches high, pyramidal - in general outline; main axis with long, wide-spreading branches - at the base; branches rather robust and naked below, but numerous - and becoming very fine and tufted at top; cystocarps adherent or - on short stalks; siphons four in number; main stems corticated; - ultimate branchlets show articulations; color brownish-red. It is - common from New York northward. (Plate XXVII.) - - ^P. urceolata.^ Frond three to ten inches high; main stem - bristle-like; branches naked below, divided and subdivided above; - branches with short branchlets set at a wide angle and often - recurved; siphons four in number; shows articulations; color deep - red. Name refers to cystocarp, which resembles a pitcher. The plant - grows in loose tufts, and is common from New York northward and on - the California coast. - - Variety ^formosa^. Filaments soft and finer than in /P. urceolata/; - branches long and flexuous; articulations five to ten times longer - than broad; color bright red. It grows in tufts sometimes a foot - long, and is found only in the spring. - - [Illustration: PLATE XXVII. Polysiphonia nigrescens. Polysiphonia - fibrillosa. Polysiphonia violacea. Polysiphonia Woodii.] - - [Illustration: PLATE XXVIII. Laurencia pinnatifida. Dasya elegans. - Dasya plumosa. Dasya plumosa, magnified.] - - ^P. variegata.^ Fronds four to ten inches high; filaments thick as - a bristle below, and branched in a forking manner to the very top; - divided at long intervals below, at the top becoming of hair-like - fineness [pg089] and dividing rapidly, forming a densely - tufted mass, which collapses when taken from the water; color - purple-brown; when mounted, silky in appearance; filaments banded; - siphons six in number. It forms purple tufts on woodwork and on - eel-grass from Cape Cod southward. - - ^P. Woodii.^ Fronds four to six inches high; branches flat, long, - wide-spreading, emanating from the edges in one plane; younger - branches show articulations; ultimate branchlets inclined to curve - inward; color light brown. Found on the California coast. (Plate - XXVII.) - - -GENUS ^Laurencia^ - - ^L. pinnatifida.^ Frond flat, thick, leathery; main stem with - opposite, or alternate, branches of about the same size and - character as itself; all pinnatifid, or cut on the edges into - branchlets, some of which are again divided; color bright purple, - often unevenly faded. It is found on the Pacific coast. (Plate - XXVIII.) - - -GENUS ^Dasya^ - -Chenille-weed. - - ^D. elegans.^ Fronds from six inches to three yards long; main stem - and branches cylindrical, and all densely clothed with a fine, - hair-like fringe, which gives the plant the appearance of chenille; - cystocarps on stalks along the branches; color pink or lake-red. - Out of water it seems like a mass of purple jelly. It is found at - or just below low-water mark from Cape Cod southward, and is very - plentiful in New York Bay. (Plate XXVIII.) - - ^D. plumosa.^ A species found on the California coast. The fringe - covering the stems consists of minute leaflets instead of hairs, as - in /D. elegans/. (Plate XXVIII.) - - -GENUS ^Bostrychia^ - - ^B. rivularis.^ Fronds one inch high; color dark purple; branches - fine and irregularly bent. It grows where the water is not very - salt, and is found in patches on submerged logs near New York. - Common from Charleston, South Carolina, southward. (Plate XXIX.) - - -GENUS ^Rhodomela^ - - ^R. subfusca.^ Frond six to eighteen inches long; main stem - cylindrical, and branching widely on all sides; branches longest - at base and gradually shortening to the top of the stem; branches - naked below, but at the ends profusely branched, forming tufts of - branchlets. It is a perennial plant, and changes in aspect with - the season. When mature it is stiff and coarse, and when dry it is - quite black. Common from New York northward. - - ^R. Rochei.^ This species resembles in form /R. subfusca/, but - is much finer and more delicate. In spring it is a soft, fine, - feathery, and beautiful [pg090] alga of a red-brown color. It - is found washed ashore, or in deep tide-pools, south of Cape Cod. - (Plate XXIX.) - - ^R. larix.^ Frond cylindrical, robust, six to fourteen inches high; - branches of unequal length standing out horizontally all around the - main stem; clusters of branchlets growing spirally around stem and - branches. Found on the northern California coast. (Plate XXIX.) - - ^R. floccosa.^ Frond four to ten inches high; less robust than /R. - larix/; stem and branches flat and divided in one plane; branches - alternate; ultimate branchlets somewhat incurved; color black. In - fertile plants the terminal branchlets are gathered in a mass. - Found on the California coast. (Plate XXIX.) - - -GENUS ^Chondria^ - -Plants of this genus are distinguished by having the ultimate -branches attenuated at the base. - - ^C. dasyphylla.^ Frond four to eight inches high; general outline - pyramidal; branches alternate on main stem; stem and branches - covered with short, club-shaped (blunt at top, attenuated at base) - branchlets; cystocarps, or spore-cases, adherent to branchlets or - on short stalks; color light or dull brown. It grows in tufts, and - is common from New York to Cape Cod. (Plate XXX.) - - ^C. tenuissima.^ This species is similar to /C. dasyphylla/, but - is more slender, and the branchlets taper at both ends instead of - being club-shaped. - - ^C. striolata.^ A species similar to /C. tenuissima/. The - branchlets bear secondary branchlets, and the cystocarps are on - short stalks. It is plentiful in Long Island Sound. - - -SUBORDER ~CERAMIEAE~ - - -GENUS ^Callithamnion^ - -These are very beautiful and delicate plants, growing in small, -soft, silky tufts, bright red in color, with darker dots along the -much-branched filaments. There are many species, and they are common -on the northern shores of both oceans; but the different species are -not easy to distinguish with the naked eye, and so but a few of them -are described below. The special characteristics by which the genus -may be recognized are: fronds filamentous, of cobweb fineness, one -inch to six inches long, much branched, and closely crowded at the -top; brilliant red color. - -[Illustration: PLATE XXIX. Bostrychia rivularis. Rhodomela Rochei. -Rhodomela larix. Rhodomela floccosa.] - -[Illustration: PLATE XXX. Chondria dasyphylla. Callithamnion -americanum. Callithamnion Pylaisaei. Callithamnion Pylaisaei, a piece -magnified.] - - ^C. americanum.^ Frond three to six inches long, densely tufted; - filaments of extreme fineness; main branches alternate; much - branched; main and secondary branches have pairs of branched - ramuli along the [pg091] branches; color rose-pink. It grows - on wharves and on algae below low-water mark, and is a common and - beautiful species. It is found (but only in the spring) from New - York northward, and is abundant in Long Island Sound. (Plates XXX, - XXXI.) - - ^C. Pylais[oe]i.^ Fronds three to six inches long, more robust - and darker in color than in /C. Americanum/; main and secondary - branches alternate, decompound, all bearing at short intervals - short opposite branchlets, which in turn are covered with ramuli. - It is found in spring on wharves and on algae from Boston northward. - (Plate XXX.) - - ^C. Baileyi.^ Fronds one inch to three inches long, with main - stem as thick as a bristle, and running to the top of the frond; - branches around the main stem longer at the base than at the - apex, giving the plant a pyramidal outline; branches also have a - main stem and short branches beset with branchlets; shrub-like in - aspect; color purplish-red. Common in summer from New York to Cape - Cod. - - ^C. seirospermum.^ Frond two to five inches high, pyramidal in - outline; has main stem and alternate lateral branches; branches - have secondary branches beset with delicate, erect branchlets; - hair-like in fineness. It is common from Cape Cod southward, and is - plentiful in Long Island Sound. (Plate XXXI.) - - ^C. byssoideum.^ Fronds one inch to three inches long; filaments - very delicate; main branches many times divided; secondary branches - long; many branchlets; rose-colored. It grows in globose tufts, and - is common in Long Island Sound. (Plate XXXI.) - - ^C. floccosum.^ Fronds three to six inches long, hair-like in - fineness; flaccid; main branches sparingly branched below; - numerous alternate branches above; all clothed with short, simple - branchlets; color dark brownish-red. The plant is so exceedingly - fine that it is difficult to distinguish the divisions. It grows on - eel-grass and on algae below low-water mark, and is found from New - York to Cape Cod. (Plate XXXI.) - - -GENUS ^Griffithsia^ - -(/Named for Mrs. Griffiths, an English algologist/) - -These are among the most beautiful of seaweeds, because of their -brilliant color and exceedingly delicate structure. They grow in deep -water, and specimens cast ashore are usually torn and imperfect, but -they may often be gathered from deep tide-pools, and sometimes are -found growing on eel-grass. If placed in fresh water they discharge -their coloring-matter and quickly decompose. - - ^G. Bornetiana.^ Fronds two to five inches high; filaments jointed, - the divisions being long and pear-shaped, growing shorter as they - near the top; repeatedly forked; very soft and fragile. It grows - in tufts, resembling corals; attains perfection in July, and - disappears later in the summer. Found from Cape Cod southward, - washed ashore after storms. (Plate XXXII.) [pg092] - - -GENUS ^Ptilota^ - -Feather-weed. - - ^P. serrata.^ Fronds three to six inches long, dark red in color, - cartilaginous; flattened main stem with opposite, flattened - branches, one of which is minute, so that it appears like alternate - branching; branches also have lateral branchlets and pinnulae, - looking like feathers or ferns; all branching in one plane, making - a flat frond. It is found in the drift on the beach after a storm, - and is common from Cape Cod northward, and also on the California - coast. (Plate XXXII.) - - ^P. elegans.^ Narrower and more delicate than /P. serrata/, - otherwise it has the same essential features. It is common in - summer from New York northward, growing on cliffs, under /Fucus/, - near low-water mark, and it is also found washed upon the beach. - (Plate XXXII.) - - ^P. densa.^ Frond three to twelve inches high, one eighth of - an inch wide, flat, cartilaginous; has leading stem with flat - alternate branches; branches simple or branched again; edges of - whole plant beset with notched, curved pinnulae alternating with - smaller feather-like pinnulae, giving a dense edge to all parts of - the frond. It is found on the California coast. (Plate XXXIII.) - - ^P. hypnoides.^ Flat, cartilaginous main stem, much branched, and - all beset with pinnulae. It differs from /P. densa/ in having the - alternate pinnulae straight and club-shaped, instead of toothed and - curved, and the plant is not so dense and compact. Found on the - California coast. (Plate XXXIII.) - - -GENUS ^Spyridia^ - - ^S. filamentosa.^ Fronds four to eight inches long; filaments as - thick as bristles, irregularly and repeatedly branched; young - branches show articulations and seem to be striped; all branches - clothed with short, very delicate, transparent filaments, which - give the plant a hazy appearance; color purplish-red, which becomes - brown when dried; does not collapse when taken from the water. It - grows in tufts below low-water mark, and is found in the drift on - the beach from Cape Cod southward. (Plate XXXIII.) - - -GENUS ^Ceramium^ - -The pitcher-weed. This genus is easily recognized by the ends of the -filaments, which are forked and incurved, resembling minute pincers -or claws. The filaments are also more or less distinctly banded. It -is widely distributed. - -[Illustration: PLATE XXXI. Callithamnion americanum, a piece -magnified. Callithamnion seirospermum. Callithamnion byssoideum, var. -fastigiatum. Callithamnion floccosum.] - -[Illustration: PLATE XXXII. Griffithsia Bornetiana. Ptilota serrata. -Ptilota serrata, magnified. Ptilota elegans.] - -[Illustration: PLATE XXXIII. Ptilota densa. Ptilota hypnoides. -Ptilota hypnoides, magnified. Spyridia filamentosa.] - - ^C. rubrum^, red ceramium. This is a very common and robust - species, found everywhere, and growing on everything. It is - variable in appearance, becoming quite coarse when old, the - incurving, claw-like ends, which are characteristic of the genus, - being less pronounced. It branches by repeated forking, and, under - the microscope, shows a bark-like [pg093] layer of cells over - the whole surface, which make the ring-like bands on the filaments - less conspicuous. - - [Illustration: PLATE XXXIV. Ceramium rubrum, var. proliferum. - Ceramium rubrum, top of frond magnified. Ceramium diaphanum. - Ceramium tenuissimum, var. patentissimum.] - - Variety ^proliferum^. Fronds beset on all sides with simple or - forked branchlets. (Plate XXXIV.) - - Variety ^secundatum^. Branchlets generally arranged on one side of - the filaments, or secund. - - ^C. strictum^ ("straight"). Brown or purplish-red filaments of - hair-like fineness, growing in tufts two to six inches high, - branching in narrow forks more and more closely as they reach the - top of the frond. There are no principal branches, the filaments - being of about the same diameter and regularly dividing in a - forking manner throughout. The filaments are banded, the red rings - being relatively very narrow. The white interstices at the base are - several times longer than broad, but shorten gradually until at the - top they are of equal length with the red bands. This species is - common from Cape Cod to New York. - - ^C. diaphanum.^ This species has comparatively stout leading - branches, with secondary alternate branches which are finer than - the main stems and divide in a forking manner throughout, and - ultimately become very fine. The color is brown or purplish-red, - distinctly banded. It grows on eel-grass and algae, and is found - from Cape Cod to New York. (Plate XXXIV.) - - ^C. fastigiatum.^ Filaments of hair-like fineness and of about same - size throughout; branched in regular forking manner throughout, - the divisions being wide and distant at the base, but gradually - becoming closer and narrower as they reach the top; the upper - segments about equal, giving a level top and regular outline in - mounted specimens; the terminal forks erect, or less incurved than - in other species; small points or branchlets emanate from some of - the nodes or joints between the bands of color; tufts globe-shaped, - two to five inches high; color lake-red. This species grows on - mud-flats and mud-covered rocks as well as on algae and eel-grass. - - ^C. tenuissimum.^ Fronds two to four inches high, densely tufted; - the forked divisions very wide or open; color rose-pink. - - Variety ^patentissimum^. Fronds small; the forked divisions distant - and very wide open. A mounted specimen appears somewhat like - network. The species is common in Long Island Sound. (Plate XXXIV.) - - -GENUS ^Microcladia^ - - ^M. Coulteri.^ Cylindrical, slightly flattened main stem; branches - set uniformly and alternately, short at the base, gradually - lengthening as far as the center, and from there diminishing to - the apex of the stem, giving a leaf-like outline. The same mode - of branching and the same outline are repeated in the branches. - The ultimate divisions are like forked divisions, and are somewhat - incurved. The plant is six to eight inches high, and in color is - of many shades of red and pink. It is found in abundance on the - Pacific coast at all seasons. (Plate XXXV.) - - ^M. borealis.^ Branches and branchlets placed on one side of arched - main stems; secondary branches curved in opposite direction and - bearing branchlets, also divided on one side only; color dark - brown. It is found on the northern Pacific coast. (Plate XXXV.) - [pg094] - - -ORDER =CRYPTONEMIACEAE= - - -SUBORDER ~GLOIOSIPHONIEAE~ - - -GENUS ^Gloiosiphonia^ - -("/Viscid tube/") - - ^G. capillaris.^ Frond six to ten inches high, solitary or in - tufts; main stem cylindrical, solid above, hollow below; from about - an inch above the base densely beset with short, wide-spreading - branches arranged evenly and all around the stem; branches again - branched in the same way; branches and branchlets attenuated at - base and apex; soft, tender, juicy; shrinks much in drying. The - species is easily recognized by its delicate gelatinous substance, - tapering branchlets, and brilliant red color. It is found in early - summer in tide-pools on the New England coast. - - -SUBORDER ~GRATELOUPIEAE~ - - -GENUS ^Halymenia^ - - ^H. ligulata.^ Frond membranaceous, repeatedly and regularly - divided in a forking manner; the larger divisions one half of an - inch wide and growing very narrow at the top; four to five inches - high, spreading in a fan-shape; color rose-red. It is found at Key - West. - - -GENUS ^Grateloupia^ - - ^G. Cutleria.^ Frond coarse, flat, variable; either simple, - long, and narrow, or short and broad, tapering at both ends, or - blunt at the apex, or deeply cleft into many segments; sometimes - with leaflets along the edges; height two to three feet; color - reddish-brown; in fading, changes to purple and green, and may be - variegated. When simple, the plant resembles /Iridaea/. Found on the - northern California coast. - - -GENUS ^Prionitis^ - - ^P. lanceolata.^ Frond narrow, flat, smooth; leathery stems, which - branch irregularly and sparingly from the edges; branches bordered - with lance-shaped leaflets; color dark brownish-red; plant ten or - more inches high, and varies considerably. (Plate XXXV.) - - There are other species, among them ^P. Andersonii^ (Plate XXXVI.); - all are easily distinguished by the lance-shaped leaflets. Common - on the Pacific coast. - -[Illustration: PLATE XXXV. Microcladia Coulteri. Microcladia -Coulteri, magnified. Microcladia borealis. Prionitis lanceolata.] - -[Illustration: PLATE XXXVI. Prionitis Andersonii. Pikea Californica. -Halosaccion ramentaceum. Polyides rotundus.] - - -SUBORDER ~DUMONTIEAE~ - - -GENUS ^Pikea^ - - ^P. Californica.^ Divisions of frond thick, narrow, cartilaginous; - central axis one eighth of an inch to one inch wide, three to four - inches high, thickly set with similar branches irregularly placed; - all bordered [pg095] with numerous forward-pointing branchlets, - which in turn have spine-like ramuli of various lengths; frond - flat, broadly spreading; dark red. It is common at all seasons on - the California coast. (Plate XXXVI.) - - -GENUS ^Halosaccion^ - - ^H. ramentaceum.^ Fronds brownish-purple, six to fourteen inches - long, coarse and cartilaginous, cylindrical, hollow, compressed, - attenuated at the base; more or less covered with simple or forked - hollow branches half the size of the main stem. In exposed pools - the plants are short and densely branched; in sheltered places they - are larger and more delicate in texture. They are common on the - northern New England and northern California coasts. (Plate XXXVI.) - - -SUBORDER ~RHIZOPHYLLIDEAE~ - - -GENUS ^Polyides^ - - ^P. rotundus.^ Frond three to six inches high, cylindrical, - cartilaginous, repeatedly forked, ends obtuse; spore-masses form - numerous lighter-colored excrescences on the upper divisions of the - frond; dark red. Common from New York northward, in deep pools and - washed ashore. (Plate XXXVI.) - - -SUBORDER ~SQUAMARIEAE~ - - -GENUS ^Peyssonnelia^ - - ^P. Dubyi.^ Frond completely adherent to the rock or stone on - which it grows; color dark purple; somewhat calcareous; redder and - thicker than next species. It is found at low-water mark or in deep - water on the northern New England and northern California coasts. - - -GENUS ^Petrocelis^ - - ^P. cruenta.^ Frond closely adherent, forming dark-purple velvety - patches of indefinite outline on rocks and stones. Common north of - Cape Cod. - - -GENUS ^Hildenbrandtia^ - - ^H. rosea.^ Forms continuous pink incrustations of considerable - extent on stones and rocks at low-water mark. Common everywhere. - - -SUBORDER ~CORALLINEAE~ - -The genera of this suborder are characterized by a calcareous or -stony incrustation of the fronds, which gives them the appearance of -corals. Most of the species are tropical. [pg096] - - -GENUS ^Corallina^ - -("/Coral-like/") - - ^C. officinalis^, common coralline. Frond grows from a disk in - tufts more or less dense. The plant is rigid, and seems like - jointed, branched coral. The articulations are cylindrical at the - base, wedge-shaped and flattened above. Branches emanate from the - top of the articulations. The color varies from reddish-purple to - gray-green, and is often bleached white when exposed to the sun. - Common in tide-pools and on rocks at low-water mark from New York - northward. (Plate XXXVII.) - - -GENUS ^Melobesia^ - -This genus will attract attention, although it cannot be gathered. It -is a thin, brittle, scaly substance of indefinite form, which expands -horizontally and resembles a lichen. It forms brown and pink crusts -on other algae and on rocks, stones, and shells. - - -ORDER =BANGIACEAE= - - -GENUS ^Bangia^ - - ^B. fusco-purpurea^ ("brown-purple"). Fine, hair-like, unbranched, - dark-purple filaments, one inch to six inches long. It grows in - large patches on rocks and woodwork, floating free, but falling - into soft, silky, fleece-like masses when left by the tide. Common - on northern shores. (Plate XXXVII.) - - -GENUS ^Porphyra^ - -("/Purple dye/") - -This plant, except in color, is like the green alga /Ulva/. In -color it is purple of various shades. The species are named from -variations in the outline of the frond. They are found everywhere, -and throughout the year. The plants are edible, being the laver of -commerce, eaten principally by the Chinese, who make them into soup. - - ^P. vulgaris.^ Frond a broad, thin membrane of purple color, three - to twelve inches across; margin much waved; sometimes attached at - the center, often widely expanded and folded, sometimes deeply - lobed. (Plate XXXVII.) - - ^P. laciniata.^ Differs from /P. vulgaris/ in being divided into - narrow segments or into wavy, ribbon-like forms. (Plate XXXVII.) - - -[Illustration: PLATE XXXVII. Corallina officinalis. Bangia -fusco-purpurea. Porphyra vulgaris. Porphyra laciniata.] - - - - -PART II - -MARINE INVERTEBRATES - - - - -I - -PORIFERA - -(SPONGES) - - -TABLE SHOWING THE CLASSIFICATION OF THE SPONGES DESCRIBED IN THIS -CHAPTER - - Phylum and Class =PORIFERA= - - Subclass =Calcarea= - - Order =HETEROC[OE]LA= - - Family ~SYCONIDAE~ - - Genera Species - - ^Grantia^ ^G. ciliata^ - ^Leucosolenia^ ^L. botryoides^ - - Subclass =Non-Calcarea= - - Order =CHONDROSPONGIAE= - - Family ~SUBERITIDAE~ - - ^Suberites^ ^S. compacta^ - ^Polymastia^ ^P. robusta^ - ^Cliona^ ^C. sulphurea^ - Order =CORNACUSPONGIAE= - - Family ~DESMACIDONIDAE~ - - ^Esperiopsis^ ^E. quatsinoensis^ - ^Microciona^ ^M. prolifera^ - - Family ~HETERORRHAPHIDAE~ - - ^Tedania^ - - Family ~HOMORRHAPHIDAE~ - - Genera Species - - ^Halichondria^ ^H. panicea^ - - Family ~SPONGIDAE~ Subfamily ~EUSPONGINAE~ - - ^Chalinopsilla^ ^C. oculata^ - ^C. arbuscula^ - ^Euspongia^ ^E. officinalis^ - Var. ^adriatica^ - Var. ^mollissima^ - Var. ^rotunda^ - Var. ^dura^ - ^Hippospongia^ ^H. equina^ - Var. ^cerebriformis^ - Var. ^meandriformis^ - Var. ^elastica^ - ^H. canaliculata^ - Var. ^gossypina^ - Var. ^flabellum^ - - Family ~SPONGIDAE~ Subfamily ~STELOSPONGINAE~ - - ^Hircinia^ ^H. campana^ - - -[pg101] - - - - -SPONGES - - -There are many animals which consist of but one cell. These are -called /Protozoa/, and comprise the /Infusoria/ and other microscopic -organisms. The animals next higher in the scale are /Metazoa/, or -multicellular animals, and the first group of this subdivision is -=Porifera=, the sponges, the lowest of the many-celled animals. - -For a long time sponges occupied a disputed ground between the animal -and vegetable kingdoms. Aristotle was the first to point out that a -sponge is not a plant. The assertion was doubted and combated, but at -last the animal nature of the sponge was established. Sponges were -then believed to be colonies of one-celled animals, but finally it -was decided that they were individuals with cells of different kinds -that performed functions analogous to those of higher organisms. - -The sponge, as commonly seen, is only the skeleton or framework, so -to speak, of the living animal. In its natural state it is a very -different-looking object. Its entire surface is covered with a thin -slimy skin, usually of a dark color, which is perforated with holes -corresponding to the apertures of the canals. The organic portion -of the sponge is a soft, jelly-like substance composed of three -layers--the external (/ectoderm/), the internal (/endoderm/), and -the middle (/mesoderm/). The external layer is composed of flat -cells. The endoderm has cylindrical cells, each one of which has a -flagellate hair. The main mass of the body, the mesoderm or middle -layer, is made up of cells having various functions, some being -concerned in the formation of framework, some in digestion, and some -in reproduction. - -The framework is secreted in the mesoderm, and in different -[pg102] genera consists respectively of a horny or silicious or -calcareous substance, or of the first two of these substances -combined. The sponge of commerce has the first kind and is composed -entirely of exceedingly fine flexible fibers of a horny substance -called /spongin/. In other species the spongin is intermixed with -spicules of silica, or of carbonate of lime, in various shapes. -In the sponges, so much valued as curiosities, called "Venus's -flower-basket" and "glass-rope sponge," the framework is composed of -silicious spicules alone. - -[Illustration: Various forms of sponge-spicules.] - -The spicules have a great variety of shapes, being rod-like, knobbed, -three-pointed, six-pointed, anchor-like, etc., and are a feature in -the classification of sponges. - -[Illustration: To illustrate choanocytes (/Ch/): section of a -calcareous sponge. /Ect/, ectoderm; /Mes/, mesoderm; /N/, calcareous -spicule; /Eiz/, ovum.] - -The sponge is traversed throughout by a canal system, consisting of a -series of tubes through which water circulates, carrying air and food -to the animal. The exterior of the sponge has numerous small pores -and a comparatively few large openings. The fine pores are inhalent, -taking in and straining the water of its coarser floating material, -and then passing it through perforations in their sides into sacs -lined with peculiar cylindrical cells having flagellate hairs, each -hair having a collar at its base. These cells, called /choanocytes/, -resemble independent animals of the /Protozoa/, known as /flagellate -Infusoria/ or /Choanoflagellata/. [pg103] They take in and digest -food and eject excrement from the area inclosed by the collar. The -cilia (hairs) by their constant movement create currents which keep -the water in motion. Water, then, is taken through the pores into -the first or incurrent canals; thence it is passed into the ciliated -chambers, and thence into the excurrent canals, and out through large -passages terminating in large openings called /oscula/, or craters. -The canal systems vary. In some species they become quite complex. - -[Illustration: Canal system of /Sycon gelatinosum/. Transverse -section through the wall of a cylinder (parallel with the course of -the canals), showing one incurrent canal (/IC/) and one radial (/R/) -throughout their length; /sp/, triradiate spicules; /sp'/, oxeate -spicules of dermal cortex (/dc/); /sp''/, tetraradiate spicules -of gastral cortex (/gc/); /ec/, ectoderm; /en/, endoderm; /pm/, -pore-membrane; /pp/, prosopyle; /ap/, apopyle; /di/, diaphragm; -/exc/, excurrent passage; /PG/, paragastric cavity; /em/, early -embryo; /em'/, late embryo. (The arrows indicate the course of the -water through the sponge.)] - -Sponges vary greatly in shape, size, color, surface, rigidity, -canal systems, and skeleton. They are cake-shaped, tubular, -digitate, palmate, cup-shaped, vase-shaped, cone-shaped, spherical, -hemispherical, pedunculate, etc., their shapes depending upon whether -their growth is uniform or is excessive in a horizontal or in a -vertical direction. When they grow evenly in both directions massive -uniform shapes arise. If lateral growth predominates, broad, low, -and incrusting shapes result. When there is an excess of vertical -growth the forms are digitate; [pg104] but if vertical growth is not -greatly in excess and is restricted to the marginal part, cup-shaped -forms result, and tubular forms when lateral growth is particularly -restricted. In some varieties tubular masses coalesce; sometimes flat -forms unite in intricate compressed folds. Differences in rapidity of -vertical growth make undulations more or less marked, producing lobes -and protuberances. Sometimes narrow vertical growth is retarded and -horizontal growth predominates, forming various shapes on apparent -stems. - -Many of the horny sponges are colored, in shades of yellow, brown, -red, and violet; some are black. - -Sponges are divided into two classes, the =Calcarea= and -=Non-Calcarea=. The former have calcareous skeletons, which make them -hard and rigid; the latter have skeletons of spongin-fiber or of -silicious spicules, or of the two combined. - -All sponges, with the exception of one family (the /Spongillidae/, -which live in fresh water), are inhabitants of the sea, and live at -various depths. The sponges of commerce belong to the /Non-Calcarea/ -and are all confined to the genus /Spongia/. In this genus the -skeleton is more or less flexible, being composed of spongin. They -are shallow-water species, are confined to seas where the waters are -of comparatively uniform high temperature, and flourish best when -protected by reefs and islands. - -There are fisheries for sponges in the waters of the West Indies, the -Bahamas, on the southern and western coasts of Florida, and in the -Mediterranean and Red seas. Those of the Mediterranean surpass in -quality the sponges of our coasts. - -Five species of commercial sponges are taken from Florida waters. -They are graded by the trade in the order of their importance, as the -"sheepswool," "yellow," "grass," "velvet," and "glove." The fishing -for sponges is done from small boats, two persons manning each boat. -One man sculls, while the other, using a water-glass, scans the -bottom. The water-glass is a box with a pane of glass on the bottom. -If the glass is held below the surface and the face is placed in -the box, the observer is enabled to see with some distinctness the -bottom at a considerable depth [pg105] in these clear waters. The -sponges are dragged up by hooks--a primitive method which restricts -the fishing to shallow water, the fishing here being in water not -deeper than thirty feet, but usually three to twenty feet. The -sponges are "killed" by being exposed on the beach for several days; -they are then placed in "crawls," or pens, where they are washed by -the action of the waves for about a week; then, if clean, they are -dried, assorted, strung on cords, pressed and baled for shipment. The -sponge-fisheries are of considerable value, and much attention is -being given to the subject of artificial propagation. It is thought -that such beds could be subjected to the regulations which govern -oyster-beds. Already the planting of sponges has been shown to be -practicable. The living sponge is cut to pieces, and the cuttings -are placed in favorable localities. Pieces planted in Florida waters -attain a marketable size in one year. - -Sponges reproduce by eggs formed in the mesoderm. The eggs escape as -ciliated spheres and swim about until they find a place on which to -attach themselves. As soon as they become fixed they grow with much -rapidity into mature individuals. - -Some species seem to prefer association with other animals and live -as commensals with crabs. The crab /Dromia/ is always concealed under -a sponge, which grows upon its back. Spider-crabs are often overgrown -with sponges as well as seaweeds. In this case, however, the crab -finds and plants the sponge himself. /Aplysella violacea/ overgrows -worm-tubes. Many sponges afford shelter to numerous small animals -which bore into their bodies for protection, no animal seeming to -feed upon the sponge. - -Sponges may be found in tide-pools, on the under side of stones, -on seaweeds, and so on. A small bright-red incrusting sponge with -irregular lobe-like branches is common on the New England coast; a -thin yellow incrusting sponge also is found on the under side of -stones. /Grantia ciliata/, a small urn-shaped species, having a large -aperture at the summit, is found in tide-pools. - -Perhaps the most singular in habit of any sponge is /Cliona -sulphurea/, the boring-sponge, a common species found from Cape -Cod to South Carolina and abundant in Long Island Sound. It -[pg106] is bright sulphur-yellow in color, grows in irregular -masses of considerable size and fine texture, and has low wart-like -prominences. It lives on shells spreading over both surfaces, at -first forming little burrows, but eventually penetrating the shell in -every direction, honeycombing and at last completely destroying it -by absorption. Sometimes it settles upon living shells and greatly -irritates the animal, which constantly secretes new lime to cover the -perforations in its shell. - -These sponges are an important factor in the economy of the sea, as -they disintegrate dead shells, which would otherwise accumulate in -vast quantities. - - -SUBCLASS =CALCAREA= - - -GENUS ^Grantia^ - - ^G. ciliata.^ Small, urn-shaped or oval, with large aperture at the - summit, surrounded by a circle of projecting spicules. It is found - in tide-pools and on piles of wharves from Rhode Island northward. - - -GENUS ^Leucosolenia^ - - ^L. botryoides.^ Tubular, branched. Occurs in the same places as - /Grantia ciliata/. - - -SUBCLASS =NON-CALCAREA= - - -GENUS ^Suberites^ - - ^S. compacta.^ Elongated, compressed masses, sometimes in several - lobes; attached by one edge; texture fine, firm, compact; surface - smooth; color bright yellow. It grows on sandy bottoms, and is - common in shallow water south of Cape Cod. (Plate XXXVIII.) - - -GENUS ^Polymastia^ - - ^P. robusta.^ When young it forms yellowish-white incrustations - over shells and stones; later it grows into long, slender, round, - tapering, finger-like projections. Found on the northern New - England coasts in deep water. - - -GENUS ^Cliona^ - - ^C. sulphurea^, the boring-sponge. Irregular massive form of firm - texture; surface covered with scattered low wart-like prominences - about one eighth of an inch in diameter; bright sulphur-yellow. It - destroys, by absorption, vast quantities of dead shells. - -[Illustration: PLATE XXXVIII. Halichondria panicea. Suberites -compacta. Hircinia campana. Esperiopsis quatsinoensis (found on the -sea-beaches of Alaska).] - -[Illustration: PLATE XXXIX. Microciona prolifera. Chalinopsilla -arbuscula. Chalinopsilla imitans. Euspongia officinalis, var. tuba. -Chalinopsilla oculata.] - - -GENUS ^Microciona^ - - ^M. prolifera.^ When young this species forms bright-red - incrustations over shells and stones; later it rises into irregular - lobes and tubular prominences. When fully developed it is profusely - branched in a forking manner. The branches are more or less - flattened, and often are palmate at the ends. It grows in clusters - six inches in diameter, of a dark orange-red color. When dry it is - grayish-brown, brittle, and bristly. It is found from Cape Cod to - South Carolina, and is abundant in Long Island Sound. (Plate XXXIX.) - - -GENUS ^Tedania^ - -Irregular, uneven, pale-yellow masses spreading over seaweeds; oscula -scattered irregularly over the surface; texture close. - - -GENUS ^Halichondria^ - - ^H. panicea^, crumb-of-bread sponge. It resembles the crumb of - bread, and is found cast up on all beaches. (Plate XXXVIII.) - - -GENUS ^Chalinopsilla^ - - ^C. oculata^, the finger-sponge. Stem stout, more or less - flattened, dividing at the upper end into branches which vary in - form and thickness, being finger-like or more or less compressed - lobes; oscula scattered over the smooth, undulating surface; - texture rather hard, but delicate; color, when living, dull - orange-red; when the animal matter is removed, white. The species - is found in shallow and deep water from New York to Labrador. - Common in Massachusetts Bay. (Plate XXXIX.) - - ^C. arbuscula.^ Profusely branched in a forking manner from close - to the base; branches slender; clusters six to eight inches high - and about the same in breadth; color buff or gray when living, - yellowish-white when free from animal matter; texture finer and - more delicate than that of /C. oculata/. It is found in shallow - water from Cape Cod to North Carolina, and is abundant in Long - Island Sound. (Plate XXXIX.) - - -GENUS ^Euspongia^ - - ^E. officinalis.^ This is one of the commercial sponges and is - known as the "glove-sponge." It is the one of least marketable - value, having inferior elasticity and becoming brittle with - age; yet a Mediterranean sponge of the same species, variety - /adriatica/, is of the finest quality and greatest value. This - singular fact demonstrates that the quality of sponges depends - largely upon physical conditions. /E. officinalis/ has an average - height of five to six inches. It grows on rocky bottoms in shallow - water on the east coast of Florida. This species has a number of - varieties of various forms; some are dome-shaped, others tubular, - rotund, flabellate, etc. The surface is covered with fine tufts - and is generally free from ridges. On the sides are numerous small - apertures, [pg108] and one or more large oscula occur on top. The - color of the living sponge is black. (Plates XXXIX, XL.) - - ^E. officinalis^, variety ^adriatica^. More or less globose; - sometimes attached by a broad base, sometimes by a short stem; - latter form more or less club-shaped; oscula scattered over upper - surface. Found in the West Indies and the Mediterranean. (Plate XL.) - - ^E. officinalis^, variety ^mollissima^, the Levant toilet-sponge. - Generally cup-shaped; oscula on inner side of cup or on upper flat - surface; very soft and elastic. - - ^E. officinalis^, variety ^rotunda^. Usually massive; attached by a - broad base; sides vertical; oscula large and conspicuous on top, or - small in longitudinal rows on the sides. In the young this variety - may have a conical form with only one orifice, but later it has - several oscula. Its rotundity of form increases with the number of - large orifices, but in the adult stages the form varies, some being - conical, while others have the top divided into radiating ridges. - - ^E. officinalis^, variety ^dura^. Irregular, massive, horizontally - expanded, with conical process on upper surface. - - -GENUS ^Hippospongia^ - - ^H. equina.^ Some of the sponges of this species are massive, - spherical, and attached by a small base; others are horizontally - expanded or cake-shaped; some have a depression in the upper - surface and become cup-shaped. - - ^H. equina^, variety ^cerebriformis^. Massive, circular, - cake-shaped, often depressed in the center, producing a cup-shape, - attached by broad base; surface broken up by parallel longitudinal - ridges having many tufts. Cup-shaped forms predominate, and have - a more or less rough surface. This is one of the species known as - grass-sponges. - - ^H. equina^, variety ^meandriformis^, the velvet sponge. The - surface of this variety has a protruding flattened cushion of fiber - which slightly resembles the convolutions of the brain-coral. - Sometimes these cushions are extended into long pencils. The oscula - are large and ragged on the edges; the shape is irregular. The - average size is seven to eight inches in diameter. (Plate XL.) - - ^H. equina^, variety ^elastica^ (variety ^agaricina^, Hyatt), the - yellow sponge. This is the second grade of commercial sponge, - corresponding to the Zimocca sponge of the Mediterranean. It is - found growing with the "sheepswool" in a depth of two to twenty - feet, and is abundant. It is massive and cake-shaped. The whole - surface is a network covered with numerous small, fine cones. - (Plate XL.) - - The variety ^dura^ is classed with this species, which it resembles - in appearance, though it is harder in texture. - - ^H. canaliculata.^ Massive, frondose; more or less horizontally - expanded; bears finger-like processes of varying development on the - upper surface. - - ^H. canaliculata^, variety ^gossypina^, the sheepswool sponge. This - is the highest grade of the commercial bath-sponge. It is called - "sheepswool" because, perhaps, of its irregular shaggy surface. It - is covered with tufts, the larger oscula occupying the intervening - depressions. - -[Illustration: PLATE XL. Euspongia officinalis, var. adriatica. -Hippospongia equina, var. meandriformis. Hippospongia canaliculata, -var. gossypina. Hippospongia equina, var. elastica. Euspongia -officinalis.] - - Sometimes these are very numerous, the whole interior being - cavernous; again, the structure is more dense, with fewer large - openings and more of the small ones between the tufts; again, the - depressions are filled up so that the surface has fewer tufts. - When living, the color is shining black. This is the best sponge - found on the American coast, and although of coarser texture than - the best Mediterranean sponges, it is more durable and quite as - elastic. (Plate XL.) - - ^H. canaliculata^, variety ^flabellum^ (^Spongia graminea^, Hyatt). - This is one of the species of sponges of the third commercial - grade, which bear the trade-name of "grass-sponge." The shape is - cone-like, with either a flat or a funnel-shaped top. The oscula - are on the upper surface. The sides are fluted with deep furrows - which contain the small incurrent apertures. - - -GENUS ^Hircinia^ - - ^H. campana.^ The normal variety is vase-shaped, but the species - varies greatly in form. Some varieties have branches. When living, - its color is black. It is found at Key West in four to forty feet - depth. (Plate XXXVIII.) - - - -II - - C[OE]LENTERATA - (POLYPS) - - - - -Phylum - -=C[OE]LENTERATA= - -Classes - -=HYDROZOA= - -(/Zooephytes, small Jellyfishes, and a few Corals/) - -=SCYPHOZOA= - -(/Large Jellyfishes/) - -=ACTINOZOA= - -(/Sea-anemones and most of the Stony Corals/) - -=CTENOPHORA= - -(/Comb-jellies/) - - - - -C[OE]LENTERATA - - -The animals included in the phylum =C[oe]lenterata= were once all -called /zooephytes/, or animal plants, because of their resemblance -to vegetable forms. The name /C[oe]lenterata/ is derived from two -Greek words meaning "hollow" and "intestine," and it describes the -anatomical structure of each member of the group. They are commonly -known as polyps. In the simplest forms the parts which perform the -different functions cannot be distinguished one from the other, and -even in higher forms there is but little differentiation. Shakspere's -description of old age applies to them: "Sans teeth, sans eyes, sans -taste, sans everything." - -Nevertheless, this very low order of animals has, like the -higher orders, such a diversity of form and habit as to require -classification. Some of them are stationary, and of these some branch -like plants; some move about by the aid of tentacles, some move by -means of vibrating cilia, and others move by the contraction and -expansion of the soft body. - -Cuvier included them in his /Radiata/, a class comprising all the -animals whose parts diverge or radiate from a central axis. Recent -classification has divided the radiate animals into several classes. -This arrangement of parts is obviously quite different from that -of bilateral symmetry, or the disposal of parts on each side of a -longitudinal axis. The type of radiate structure is shown in polyps. -The body is a sac, in the center of which is another sac or axis. -This is the digestive cavity. Vertical partitions extend from the -central to the outer sac, forming distinct [pg114] divisions or -chambers. The number of divisions varies with the different species -and also with the age of the animal. Other partitions start from the -outer sac, and extend toward the central axis, but do not unite with -it. These partitions, called /mesenteries/, are always in definite -multiples, varying in different species, new divisions growing -between the first partitions in regular order. On the inner edge -of these partitions the eggs of the animal are formed, which, when -mature, drop into the chambers and pass through openings into the -inner sac, or digestive cavity, and out of the mouth into the water. - -[Illustration: Diagram of radiate structure.] - -The animals are classed according as the eggs are formed on all -or on special partitions, those being of the highest order where -a limitation and constancy of function is maintained. The upper -surface of the body has hollow tentacles, each one of which opens -into one of the chambers and extends outward. All parts of the animal -communicate, and whatever enters the mouth circulates through the -whole structure; and when assimilation is completed the residue -returns by the same road and is expelled through the mouth. This -structure is common to all polyps; but there are great differences -in their texture, some being soft and some horny, while others -deposit a calcareous skeleton (corals). Some grow in colonies, like -the hydroids and corals, and are stationary, others are free and -independent; some have but few, others have many tentacles; and they -differ widely in size, form, and color. - -Hydroids, sea-anemones, corals, sea-fans, starfishes, and sea-urchins -are different examples of the radiate structure. They are not, -however, all of them polyps. - -The /C[oe]lenterata/ are divided into four classes: =Hydrozoa=, which -include the colonies of zooephytes which resemble seaweeds, the small -jellyfishes which are born of these colonies, and the /millepores/, -which are colonies of zooephytes which secrete a stony instead of a -horny skeleton, yet differ in some respects from other [pg115] stony -corals; =Scyphozoa=, large jellyfishes, many of which do not have the -double form of development; =Actinozoa=, the sea-anemones and the -different forms of stony corals, including sea-fans, sea-pens, etc.; -=Ctenophora=, the jellyfishes commonly known as comb-jellies. [pg116] - - -TABLE SHOWING THE CLASSIFICATION OF THE HYDROZOA DESCRIBED IN THIS -CHAPTER - - Class =HYDROZOA= - - Order =LEPTOLINIAE= (/Branched colonies or shrub-like communities of - hydroids; some permanently fixed, others liberate swimming-bells/) - - Suborder =ANTHOMEDUSAE= (/Zooeids not covered by protective sheath; - umbrella of medusae strongly arched; egg-sacs in manubrium/) - - Division TUBULARIANS (/Without polyp-cups/) - - Genera and Species - - ^Clava leptostyla^ - ^Hydractinia polyclina^ - ^Coryne mirabilis^ - ^Sarsia^ - ^Eudendrium ramosum^ - ^Tubularia indivisa^ - ^T. Couthouyi^ - ^Parypha crocea^ - ^Corymorpha pendula^ - ^Hybocodon prolifer^ - ^Pennaria tiarella^ - ^P. gibbosa^ - ^Bougainvillea superciliaris^ - - Suborder =LEPTOMEDUSAE= (/Zooeids covered with cup-like sheaths; - umbrella of medusae thin and not very convex; egg-sacs in line - of radial canals/) - - Division CAMPANULARIANS (/Polyp-cups stalked/) - - Genera and Species - - ^Obelia commissuralis^ - ^Eucope diaphana^ - ^Oceania languida^ - ^Clytia poterium^ - ^C. bicophora^ - - Division SERTULARIANS (/Polyp-cups sessile/) - - ^Sertularia pumila^ - ^S. argentea^ - ^S. cupressina^ - - Division PLUMULARIANS (/Polyp-cups on one side of branches - only/) - - ^Aglaophemia struthioides^ - ^Plumularia falcata^ - - Family =GERYONOPSIDAE= - - ^Tima formosa^ - - Family =AEQUOREIDAE= - - ^Zygodactyla groenlandica^ - - Order =TRACHYLINAE= (/No fixed zooephyte stage; always - free-swimming medusae/) - - Suborder =TRACHYMEDUSAE= (/Tentacles spring from margin of - umbrella; manubrium long; gonads in connection with radial - canals/) - - Genera and Species - - ^Trachynema digitale^ - - Suborder =NARCOMEDUSAE= (/Tentacles spring from midway between - summit and margin of umbrella; manubrium short; gonads in - connection with manubrium/) - - Order =HYDROCORALLINA= (/Skeleton of carbonate of lime/) - - ^Millepora alcicornis^ - - Order =SIPHONOPHORA= (/Pelagic free-swimming colonies; exhibit - extreme polymorphism of zooeids/) - - ^Nanomia cara^ - ^Physalia arethusa^ - ^Vellela limbosa^ - - -TERMS USED IN DESCRIBING HYDROIDS - -^C[oe]nosarc^ ("common flesh"): The fleshy axis, or organized living -bond, by which the zooeids are organically united to one another. It -consists of three layers: ectoderm, endoderm, and mesoderm. - -^Ectoderm^ ("outside skin"): The outside one of the three organized -layers of which every hydroid is composed. - -^Endoderm^ ("inside skin"): The innermost layer. - -^Gonangium^ ("seed-vessel"): The external horny receptacle within -which the gonophores are developed. - -^Gonophore^ ("seed-bearing"): A generative zooeid. - -^Hydranth^ ("water flower"): A nutritive zooeid. - -^Hydrorhiza^ ("water-root"): The part of the colony which fixes it to -other bodies, like a root. - -^Hydrosoma^ ("water-body"): The entire hydroid colony. - -^Hydrotheca^ ("water-receptacle"): The cup-like, horny receptacle -which protects the hydranth. - -^Mesoderm^ ("middle skin"): A layer which lies between the ectoderm -and the endoderm. - -^Nematophore^ ("thread-bearing"): The name of peculiar bodies -developed in certain genera from definite points; characteristic of -plumularians. - -^Perisarc^ ("around flesh"): The transparent, chitinous shell, or -unorganized outer membrane of horny consistency, which covers to a -greater or less extent the soft parts of the colony. - -^Zooeid^ ("animal form"): One of the animals which form the colony. -[pg119] - - - - -CLASS =HYDROZOA= - -SEAWEED-LIKE ZOOePHYTES AND SMALL JELLYFISHES - - -The hydroids have been called the nurses of jellyfishes. From casual -observation these two forms would not be associated together, for the -shrub-like organisms, which so much resemble plants that they are -often collected and preserved as seaweeds, suggest only vegetable -life. Examined with a glass, however, they disclose their animal -nature. Along the stems, arranged in various ways, are small cups, -from which protrude the numerous moving tentacles of the little -polyps living within them. - -/Hydroids are colonies of associated animals living a communal life./ -The multitude of individuals composing the colony are invested with -a horny covering, the /perisarc/, which in some genera assumes a -tree-like form. Through these stems and branches runs a fleshy tube, -a thread of animal substance, which connects in one living whole -the zooeids, or individuals of the community. There is division of -labor, as in other communities: some of the zooeids obtain the food -for the colony, and have tentacles around their open mouths; others -have no mouths, but reproduce the species, and at certain stages of -development liberate swimming-bells, or small jellyfishes (medusae). - -The typical hydroid colony is attached by a kind of creeping stem -from which arises a vertical axis, which gives off short lateral, -alternate branches bearing zooeids at their ends. There is often more -complex branching. The zooeids in certain genera (tubularians) are -uncovered; in others (sertularians) they are incased in a glassy, -cup-like, horny sheath. - -Three kinds of zooeids, polyps, or hydranths--as they are -indiscriminately called--are attached to the stem. Those having -an [pg120] open end and a crown of tentacles are the nutritive -individuals. Small, club-like dilations are immature zooeids. The -/blastostyles/, or reproductive zooeids, are long, cylindrical, -mouthless, and covered. At maturity the cover is ruptured, and the -medusae have the appearance of a pile of thin saucers attached by the -middle of the convex side. When at length these saucers are set free -as little medusae, or jellyfishes, the convex side of each saucer, -or swimming-bell, is called the /ex-umbrella/; the concave, under -side, the /subumbrella/. From the center of the subumbrella projects -the /manubrium/, or stomach of the animal. At the free end of the -manubrium is a four-cornered mouth. From the attached end of the -/manubrium/ four tubes or canals diverge, and, extending through the -animal, open into a circular canal which runs around the margin of -the umbrella. When the medusa is as above described, it has reached -the highest point in its development. - -When the medusa has matured, it lays eggs, known as /planulae/. These -are spherical bodies covered with cilia (hairs), by means of which -they swim about for a time; but they finally attach themselves -to some object, there to grow and develop into hydroid colonies. -The cycle of life is thus completed. This process is known as -/alternation of generation/, or /metagenesis/, one life-history -containing two quite different forms of being. The term of life of an -individual is one year, the zooephyte stage beginning in the autumn -and the medusa stage in the spring. - -Some medusae, besides reproducing by means of eggs, multiply by -budding, small medusae growing on the manubrium or on the margin of -the umbrella. /Sarsia/ and /Lizzia/ sometimes increase by budding. - -The /Hydrozoa/ are not all of the above type. In the sertularians the -zooeids perish on the stem and have no medusa life, their reproductive -element giving rise to the hydroid form without metamorphosis. The -/Trachylinae/ have no hydroid life, being always free-swimming medusae; -others, the /Siphonophora/, live a hydroid life which is unattached, -the colony floating on the ocean; the millepores secrete calcareous -skeletons and always remain fixed, reproducing by budding. [pg121] - -Hydroids are very abundant, but are comprised in the few groups -mentioned: namely, those which live only in the fixed colonial state; -those which have alternation of generation, being first hydroids -and then swimming-bells, or medusae; those which live always in the -medusa state, the eggs of the jellyfish developing at once into -other medusae; and the /Siphonophora/, or those which have a floating -colonial state, the hydroid never being attached, but floating at -large and capable of locomotion, some of the colony having the -function of propulsion. - -Hydroids are particularly interesting as exemplifying the close -resemblance that may exist in outward appearance between animal and -vegetable life and as illustrations of communal life and of the -alternation of generation. A few examples of different types are -given below. - - -ORDER =LEPTOLINIAE= - -The members of this order agree in all essential particulars being -branched colonies having two principal forms of zooeids, the nutritive -and the reproductive. Some genera attain the length of several -inches, or even feet; others are very small tufts growing on shells -and seaweeds. The cup may completely inclose the zooeid and be close -to the stem (sessile), as in sertularians; it may be on the end of -a short stalk, as in campanularians; or it may not reach above the -base of the zooeid, as in tubularians. The genera are based upon these -differences in the perisarc. - -The hydroids, like all other classes, exist in such great variety -that it would be impracticable to describe here the many named -species; but to recognize the genera is simple. A long tubular -pedicel without a cup is characteristic of the tubularians; the -campanularians have an arborescent form and bell-shaped cups on -stalks; the sertularians have sessile cups; and the plumularians have -a feather-like form, with zooeid-cups on one side only of the branches. - -The beautiful and varied structure of these "animal plants" is most -interesting, and to be fully appreciated they should be seen [pg122] -in life and examined with a glass. Some species are confined to deep -water, but many are littoral and to be found in tide-pools, in the -chinks and crannies of rocks, under stones, and under the hanging -/Fucus/. The horny skeletons of large varieties are frequently washed -ashore, and in their tangled masses smaller living species often may -be found. - - -THE TUBULARIANS - -This division is characterized by zooeids borne on long, slender stems -which are sometimes simple and small, sometimes branching and eight -to ten inches long. The zooeid has two rows of tentacles, the central -one being sometimes on a kind of proboscis. The reproductive zooeids -are in bunches, sometimes below the outer row of tentacles, sometimes -between the two rows. The perisarc does not cover the zooeid. In color -they are commonly red or yellow. - - -GENUS ^Clava^ - - ^C. leptostyla.^ This species is found growing on /Fucus/, on the - under side of stones at low-water mark, and in tide-pools, where - it often covers several feet of the surface of the rock with a - delicate velvet-like carpet. It is red in color and is, apparently, - a soft and tender species, but it thrives on the most exposed - beaches. The colonies are cylindrical tubes about one quarter of an - inch in height, rising from a creeping stem (/hydrorhiza/). Each - tube is surmounted by a zooeid with fifteen to thirty tentacles, - which is constantly changing form by its contractions. Below the - tentacles are reproductive buds arranged in clusters. Common from - Long Island Sound northward. (Plate XLI.) - -[Illustration: PLATE XLI. Clava leptostyla. Tubularia indivisa. -Hybocodon prolifer. Coryne mirabilis. Eudendrium ramosum. Tubularia -Couthouyi.] - - -GENUS ^Hydractinia^ - - ^H. polyclina.^ The soft, pinkish covering often seen on shells - inhabited by hermit-crabs. This association of two different - kinds of animals is known as /commensalism/, and is a partnership - formed for the benefit of one or both the individuals. In this - case the mossy appearance of the hydroid conceals the shell, - while the stinging-cells with which it is invested are weapons of - defense against the enemies of the crab and also help to paralyze - its prey. In return for these favors the colony is moved about, - thereby obtaining perhaps better oxygenation. Originally it was - thought that /Hydractinia/ lived only on the shells occupied by - hermit-crabs, and that the nomadic life was essential to its - existence; but this is not the case, for it is also found growing - on rocks in tide-pools. These colonies arise from a creeping stem, - which forms a horny, root-like [pg123] network over a surface - and develops at intervals projecting points on which the zooeids - live. Each colony consists of feeding members, of reproductive - members, and of a third kind which seems to have a protective - function. These last are more slender than the others, and are - without tentacles, but are armed with lasso- or stinging-cells. The - colonies are of different sexes, the male being lighter in color - than the female colonies. The eggs develop into planulae, which swim - about for a while and then give rise to other colonies. It is found - from New Jersey northward, and is very abundant in Long Island - Sound. - - -GENUS ^Coryne^ - - ^C. mirabilis.^ A hydroid about one inch high, growing in patches - and appearing like tufts of moss on rocks between tide-marks. - When highly magnified it shows club-shaped tubes with pedicels, - terminating in zooeids, scattered over the swollen ends. The - medusa-bud is larger than the others and is lower on the tube. It - liberates a swimming-bell, which is called /Sarsia/. (Plate XLI.) - -[Illustration: Colony of /Coryne/, natural size.] - - -^Sarsia^ - - ^S. mirabilis.^ This medusa of /Coryne/ is from one quarter to - three quarters of an inch in diameter when full-grown. Its umbrella - is nearly hemispherical, and from the center hangs a manubrium. - From the margin of the umbrella hang four very long tentacles. The - shape of its body and the length of its tentacles and proboscis are - constantly changing as it moves in the water. These little medusae - are very plentiful in the spring and summer, and swim rapidly in - all directions near the surface of the water. - -[Illustration: /Sarsia/, the free medusa of /Coryne/.] - - -GENUS ^Tubularia^ - - ^T. Couthouyi.^ This species is found in the same places as - /Parypha crocea/. The stem is three to six inches long, and is - inclosed in a horny sheath, which is more or less ringed or - jointed, or it may be smooth throughout. The head, when the - tentacles are expanded, measures one and a half inches in diameter. - It has a proboscis covered with tentacles, disposed in series, - which grow successively shorter, the last being merely papillae. The - medusa-buds hang in clusters between the outer tentacles and the - proboscis. The animal grows in bunches of five to ten tubes, which - spring from a creeping, tangled stem. (Plate XLI.) - - -GENUS ^Parypha^ - - ^P. crocea.^ This is one of the most beautiful of the tubularians. - It has a large, drooping head on a stem three to [pg124] four - inches long. It is bright red in color, and from the center of the - circle of tentacles the reproductive zooeids hang in a cluster, like - a bunch of grapes. It does not liberate swimming-bells. It is found - in bunches on piles of wharves and bridges, in brackish water, on - the eastern coast as far south as Charleston, South Carolina. - - ^Corymorpha pendula.^ See Plate XLII. - - -GENUS ^Hybocodon^ - - ^H. prolifer.^ One of the largest tubularians, somewhat resembling - /Parypha crocea/. It is deep orange in color, and the head is - erect on a long stem. The reproductive zooeids are in a cluster in - the center of a double row of tentacles, and resemble a basket of - fruit. It grows singly, or in groups of two or three, in shaded - tide-pools, which are protected from the surf, and in which the - water is very pure. It is found on the Massachusetts coast, but is - not common. This species liberates swimming-bells. (Plate XLI.) - - -GENUS ^Pennaria^ - - ^P. tiarella.^ The branches are arranged alternately and at right - angles to a central stem or axis; they taper, being shortest at - the top and bottom of the stem. The zooeids are red in color, and - are arranged along the upper side of branches at considerable - intervals. The stems are black and beaded, being constricted at - intervals. The zooeids have two rows of tentacles, the upper ones - on a small proboscis. From the lower part of the proboscis deep, - bell-shaped bodies, which eventually become swimming-bells, are - developed. The species is found on rocks and eel-grass along the - whole eastern coast. - - [Illustration: /Pennaria tiarella/; a branch, natural size.] - - ^P. gibbosa.^ A species similar to /P. tiarella/, found on the - coast of Florida. - -[Illustration: PLATE XLII. Corymorpha pendula. Clytia bicophora.] - -[Illustration: PLATE XLII, A. Obelia longissima. Clytia poterium. -Sertularia pumila.] - - -GENUS ^Bougainvillea^ - - ^B. superciliaris.^ This hydroid is found in tide-pools on the - New England coast, growing in clusters, about two inches high, - attached to rocks or to mussel-shells. The stem is very slender, - and branches. It is red in color. The medusae which it liberates - are found in great numbers in the spring. The tiny swimming-bells - are nearly globular. The tentacles are long, are arranged in - four clusters on the margin, and extend in every direction. The - manubrium is yellow and short, and the mouth is concealed by four - clusters of short tentacles. On these oral tentacles [pg125] - the eggs of the animal are produced. In its habits it is sluggish, - often remaining in one position for several days. - - -THE CAMPANULARIANS - -The hydroids which have an open, bell-shaped cup at the termination -of a short, stalk-like stem, or branchlet, are mostly campanularians. -This division embraces jellyfishes of different families. Many medusae -cannot be referred with certainty to the hydroids from which they -sprang, and the medusa-buds of many of the hydroids have not been -noted. - - -GENUS ^Obelia^ (Plate XLII, A) - - ^O. commissuralis.^ This is a delicate, much-branched hydroid, five - to six inches long, found at low-water mark in tide-pools, attached - to stones and seaweeds, along the rocky shores from Nova Scotia - to South Carolina. Its branches are arranged spirally and spread - nearly at right angles to the main stem, and the main branches - subdivide in a similar manner. Every interval of the stem has a - slight curve, and at the base of every branch there are four or - five rings. The ultimate branches, or pedicels, bear at their ends - bell-shaped cups which have even edges, but are twelve-sided and - slightly incurved. The pedicels are ringed for the whole length. - The reproductive cups on short ringed pedicels are larger than - the others, and occupy the angles of the branches. These cups are - constricted and again expanded at the apex, forming an urn-like top. - - -GENUS ^Eucope^ - - ^E. diaphana.^ This species is often abundant on the fronds of - /Laminaria/ washed ashore, and also on /Rhodymenia/ and /Fucus/. - It has a creeping base, zigzag in form, but keeping a straight - course, and in its branching often forming a network over the - surface of the flat fronds. At each angle of the creeping stems - rises a pedicel about an inch high, which inclines in the direction - of the stem and terminates in a zooeid-cup similar in form to that - of /Obelia/. The medusa which this hydroid liberates is called - /Thaumatias diaphana/. The swimming-bell is very shallow and thin, - turning inside out at almost every pulsation. The tentacles are - numerous and rigid like stiff hairs. This little medusa is very - active and is abundant. The species is found from Long Island Sound - northward. - - -GENUS ^Oceania^ - - ^O. languida.^ This medusa is one inch in diameter and one half of - an inch high, and is so delicate and transparent that it is hardly - visible except in its outlines. In its early stages it is nearly - spherical and has no tentacles; later the disk flattens and has - from thirty-two to thirty-six [pg126] tentacles and numerous - eye-spots. When disturbed it flattens its disk and folds together, - leaving its tentacles sprawled in every direction. It is very - languid in its movements, and often remains in one position for - hours. These medusae are found only in the hottest hours of the day, - but are very plentiful then, shoals of them often stretching for - miles, and so thick as to touch one another. Their habitat is the - New England coast. - - -GENUS ^Clytia^ - - ^C. poterium.^ This hydroid is found creeping over seaweeds in - tide-pools from Long Island Sound northward. The main stem is - prostrate, or root-like, running over the body to which it is - attached. The stems rise as do the tubularians. The sterile zooeids - are on single stems about one quarter of an inch high. The stems - are faintly ringed for their entire length, and at the top have - a distinct ring, on which rests an open, bell-shaped cup, which - is smooth around the rim. The reproductive zooeids are on very - short pedicels, and the cups are long and cylindrical, with a wavy - outline. (Plate XLII, A.) - - ^C. bicophora.^ This species is found in the same places as the - preceding, and is of about the same size. The long stems are more - or less ringed and sometimes branched. The edges of the cups are - notched. The medusa-buds are urn-shaped and ringed, and are on very - short pedicels. (Plate XLII.) - - -THE SERTULARIANS - -The sertularians are distinguished by the horny cup, which is -sessile--that is, set directly against the stem instead of being -raised upon a stalk. They are among the most common objects of the -beach, and, like the plumularians, are often mistaken for plants by -the amateur collector and are gathered and pressed as seaweeds. They -are found everywhere along the coast. They zigzag over the fronds of -seaweeds or hang in fringes upon them, as well as upon rocks, stones, -and shells. They well repay close examination with a glass. Every -open cup bears a wreath of tentacles, which makes the branch a spray -of stars. This is not an inappropriate comparison, for besides their -starry shape some species emit a phosphorescent light. - -[Illustration: PLATE XLII, B. Sertularia argentea. Sertularia -cupressina.] - -[Illustration: PLATE XLIII. Plumularian hydroid. Aglaophemia -struthioides. Aglaophemia struthioides, magnified. Plumularia -falcata.] - - -GENUS ^Sertularia^ - - ^S. pumila.^ The most abundant of all the hydroids on the northeast - coast is this species, which is found in profusion upon /Fucus/ - and other seaweeds, and mingled with them upon the rocks. It - is easily distinguished from the campanularians because its - zooeid-cups are close against the stems (sessile) instead of on - stalks or pedicels. The stem creeps [pg127] over the fronds - of seaweeds, often crossing and recrossing in a tangled mass. At - short intervals the upright, straight branches rise to one inch or - one and a half inches in height, and are more or less branched. - All except the creeping stems are close set on each side, with - cylindrical zooeid-cups which turn outward at the ends. The cups of - the reproductive zooeids are not sessile; they are much larger than - those of the nutritive ones and are urn-shaped. (Plate XLII, A.) - - ^S. argentea.^ This is a beautiful species, common from New Jersey - northward. It has a profusion of silvery branches on a dark stem. - The colonies are often a foot or more long, and the branches at - the top and bottom of the stem are shorter and fewer than those in - the middle of the colony. The zooeid-cups are nearly cylindrical, - pressed closely to the stem, nearly opposite or subalternate to one - another, and end in pointed tips. The medusa-bud is urn-shaped, - with two horns at the top. (Plate XLII, B.) - - ^S. cupressina^, the sea-cypress. This species is similar to - /S. argentea/, but the main stem is thicker and longer, and the - branches less crowded and less subdivided. The branches are arched - or drooping, instead of straight, and gradually decrease in length - at some distance from the lower and upper parts of the stem, - giving a spire-like apex, the stem often continuing into a bare, - branchless extremity. The zooeid-cups are tubular, not much narrowed - or divergent above, and two-lipped on the margin. It is found from - New Jersey northward. (Plate XLII, B.) - - -THE PLUMULARIANS - -These hydroids are feather-like in the manner of branching, short -lateral branches being arranged on each side of a long central stem. -In some species the stems are naked below and resemble quills. The -zooeid-cups are only on one side of the short branches. (Plate XLIII.) - - -GENUS ^Aglaophemia^ - - ^A. struthioides^, the ostrich-plume. This species, which is - found on the Pacific coast, is perhaps the most beautiful of the - hydroids. It varies in size and color, but always suggests a small - ostrich-plume. The zooeid-cups are arranged in a single row on one - side of each short branch, and the main stem has a joint between - each of the branches, which are placed quite close together. The - rims of the cups have sharp-pointed teeth, and from the top emerge - three tubular projections, which are called /nematophores/, and are - supposed to be degenerate zooeids. At intervals a branch is replaced - by a cylindrical body covered with nematophores, and in these the - generative zooeids are developed. (Plate XLIII.) - - -GENUS ^Plumularia^ - - ^P. falcata^ (Johnston), or ^Hydrallmania falcata^ (Hincks). This - species is found on shells and rocks near low-water mark from Long - [pg128] Island Sound northward. It is from four to twelve inches - high. The main stem is in long spiral turns, and at intervals has - spreading plumose branches. The zooeid-cups are tubular and closely - pressed against one another, and are ranged in rows on one side of - the branchlets; the apertures of the cups are plain and oblique. - (Plate XLIII.) - - -FAMILY ~GERYONOPSIDAE~ - - -GENUS ^Tima^ - - ^T. formosa.^ A very delicate and transparent medusa; size one to - two inches in diameter; bell conical; radial tubes four in number; - manubrium long, hanging far below the disk; four frilled appendages - diverging from the corners of the mouth; tentacles thirty-two; - egg-sacs white and following the line of the radial tubes in - undulating folds. This species is not very common; it is found on - the New England coast. - - -FAMILY ~AEQUOREIDAE~ - - -GENUS ^Zygodactyla^ - -[Illustration: /Zygodactyla groenlandica./] - - ^Z. groenlandica.^ Medusa seven to eleven inches in diameter; disk - violet-colored and transparent; margin fringed with long, fine, - contractile tentacles of a darker violet color; numerous radiating - tubes; egg-sacs in slightly waved plates; manubrium hanging below - the line of the disk and with a thin frilled membrane depending - from it. Found north of Cape Cod in July. - - -ORDER =TRACHYLINAE= - -The /Trachymedusae/ are characterized by their direct development, the -egg of the jellyfish producing a medusa and not a hydroid colony. - - -GENUS ^Trachynema^ - - ^T. digitale.^ Size one inch to one and a half inches in height; - rose-colored; the bell thin and hard, and conical at the top. The - swimming is effected by contractions of the muscular velum (the - band around the inner margin of the umbrella) instead of wholly by - the bell. The tentacles are long and numerous, and are curled up - when moving. The manubrium is long and has four expansions at the - mouth. Eight egg-cases [pg129] hang in long pendent sacs from the - upper part of the radial canals and reach nearly to the velum. Four - garnet-colored eyes in club-shaped processes are prominent on the - margin. The animal moves by jerks in straight lines. - - -ORDER =HYDROCORALLINA= - -CALCAREOUS HYDROIDS - -[Illustration: /Trachynema digitale./] - -The genus ^Millepora^ ("thousand pores"), which is the type of this -order, is a colony of animals, like other hydroids, which secrete -calcareous instead of horny coverings. It differs from true corals -in that the members of a colony perform different functions, whereas -in true corals each member of a community is a complete individual. -It differs also in the arrangement of the stony partitions, which in -=Hydrocorallina= are the outside coverings and connecting canals, but -in true corals are vertical partitions inside the animal, between the -inner and outer sacs, as explained on page 114. - - -GENUS ^Millepora^ - - ^M. alcicornis^, elk-horn coral. This beautiful coral, which is - abundant in Florida and contributes to the building of the reefs, - rises in broad expansions, more or less lobed, and suggests by its - shape the object for which it is named. The whole mass is porous, - being traversed by innumerable canals. Its surface, although - smooth compared with that of other corals, is covered with very - minute pores, which are of two sizes. The larger ones are the - /gastropores/, or stomach-pores, in which the nutritive animal - lives; it has a cylindrical body, with four knob-like tentacles and - a mouth. Placed more or less irregularly around the gastropores are - smaller pores, the /dactylopores/ (finger-pores), from which emerge - slender mouthless processes, or /dactylozooeids/, with tentacles and - stinging-cells. These seem to be the guard-polyps of the community. - The cups occupied by the zooeids are shallow. As one animal dies, - another succeeds it and builds a horizontal partition separating - the new cup from the old one. Thus the stony mass increases in size - by the progress of succeeding generations of zooeids. The living - animal occupies only the outer, open space. (Plate XLIV.) [pg130] - - - -ORDER =SIPHONOPHORA= - -FREE-SWIMMING COLONIES - -This order of hydroids consists of free-floating communities and -is one of peculiar interest, since it shows in a clear manner the -special function of each individual member of the colony, and -illustrates better than the foregoing, perhaps, the curious forms of -animal life which this class presents. - - -GENUS ^Nanomia^ - -[Illustration: Adult /Nanomia cara/.] - - ^N. cara.^ This species is found on the New England coast. The - members of the community are arranged along a hollow stem about - three inches long which opens into every individual. At the top - of the stem is a sac, or float; just below this is a group of - swimming-bells which have no manubrium or mouth, and whose sole - function is to provide locomotion for the community; and below - these are three sets of zooeids, each having a triangular shield - and tentacles. The tentacles are longer than the main stem. One of - these last groups consists of the nutritive members, the mouths - of the community, resembling manubriums of swimming-bells out of - place. Each one has at the point of attachment a bunch of long, - delicate tentacles having pendent knobs of lasso-cells. A second - group, also with mouths, has shorter tentacles which are carried in - spiral coils. The members of the third group have but one tentacle - each and resemble the float at the end of the stem; presumably - these drop off and produce new colonies. There are also on the - lower part of the stem other reproductive members, which resemble - the clusters of buds seen on [pg131] tubularian hydroids. These - animals are pink in color and move through the water with a - graceful swaying motion. - - -GENUS ^Physalia^ - - -[Illustration: /Physalia arethusa/; Portuguese man-of-war, one fifth -natural size.] - - ^P. arethusa^, the Portuguese man-of-war. This colony is perhaps - the best-known one of the group, since it attracts much attention - in Southern waters, and is also one of the most remarkable - examples of an animal community. The most prominent part of the - compound body is the float, an oblong pear-shaped bag, full of - air, which floats on the surface of the water. Its color is bright - blue, varying to rose. On the upper side of this air-vessel is a - crest, or sail, and from the under side depend long tentacles, or - streamers. Some of these tentacles are covered with stinging- or - lasso-cells; some are the feeding zooeids, with flask-shaped - bodies, and some, which look like bunches of grapes, are the - reproductive zooeids. The tentacles in this curious cluster are - all close together and hang from one side of the float, near the - broader end. The longest are on the outside, which may be called - the windward side, since they serve to keep the crest, or sail, - before the wind; and when the wind is strong they stretch out to - a remarkable length,--forty to fifty feet,--acting as anchors to - keep the colony from being driven ashore. They also change its - course by raising the pointed end of the float, thus forcing it to - "come about." These long tentacles, ordinarily carried more or less - curled up, are in bunches of two to four, and emerge from a common - stem. Clusters of similar, but smaller, tentacles alternate with - the larger ones, but grow somewhat nearer the pointed end of the - float; these are purely locomotive organs. Next come two smaller - sets of appendages, also of unequal size, which are the nutritive - organs of the community. They are clustered together on a stem like - the others. The appendages of the third kind are small, resemble - bunches of grapes, and are scattered among the nutritive hydrae. - These last are the reproductive zooeids of the community. - - -GENUS ^Vellela^ - - ^V. limbosa.^ This hydroid is abundant on the Florida coast. It - has a bright-blue, flattened, oblong, bladder-like float, four to - five inches [pg132] long, which, is divided into a number of - concentric, communicating compartments. The margin of the float is - entire, and a triangular sail extends diagonally across the top. On - the under side is a single mouth on a manubrium, and surrounding it - are a large number of short thread-like appendages having different - functions. Some of them are feelers, others bear reproductive buds, - and others have stinging-cells. Associated with /Vellela/ is an - allied hydroid called /Porpita/, which has no sail, and in company - with these two is a jellyfish called /Rataria/, which is supposed - to be the offspring of one or the other of them. - -[Illustration: /Vellela limbosa./] - - -TABLE SHOWING THE CLASSIFICATION OF THE SCYPHOZOA DESCRIBED IN THIS -CHAPTER - - Class =SCYPHOZOA= (/Velum usually absent and tentaculocysts - present; the eggs are discharged into a gastric cavity. The type - of this class is Aurelia/) - - Order =STAUROMEDUSAE= (/Umbrella conical or vase-shaped; no - tentaculocysts/) - - Genera Species - - ^Lucernaria^ ^L. auricula^ - - Order =PEROMEDUSAE= (/Umbrella conical and divided by transverse - constrictions; four interradial tentaculocysts/) - - ^Pericolpa^ ^P. quadrigata^ - - Order =CUBOMEDUSAE= (/Umbrella four-sided, cup-shaped; four - perradial tentaculocysts/) - - ^Charybdaea^ ^C. marsupialis^ - - Order =DISCOMEDUSAE= (/Flattened, saucer-like or disk-shaped - umbrella; radial tubes branched; eight tentaculocysts/) - - Suborder ~CONNOSTOMAE~ (/Very small; marginal tentacles; short - and solid; mouth square without arms/) - - Suborder ~SEMOSTOMAE~ (/Square mouth with four long arms; - tentacles long and hollow/) - - ^Aurelia^ ^A. flavidula^ - ^Cyanea^ ^C. arctica^ - ^C. fulva^ - ^C. versicolor^ - ^Linerges^ ^L. mercurius^ - ^Pelagia^ ^P. cyanella^ - - Suborder ~RHIZOSTOMAE~ ("/Root-mouth/") (/Mouth obliterated by - growth of oral arms across it; tentacles absent/) - - ^Cassiopeia^ ^C. frondosa^ - -[pg134] - - - - -CLASS =SCYPHOZOA= - -THE LARGE JELLYFISHES - - -There is perhaps no marine animal which excites more wonder than -the jellyfish. Its transparency, its graceful rhythmical movements, -its long streaming tentacles, the variety and eccentricity of its -form, and often of its color, attract attention, and one naturally -desires to know something of its life-history. Jellyfishes are also -called /medusae/, because their long appendages suggest the locks of -the Gorgon; /acalephs/, on account of their stinging or nettle-like -properties; and sun-jellies, sea-blubbers, etc., because they float -upon the surface during the warmest part of the day, when the sun is -high. The name /jellyfish/ is inappropriate, since the animal in no -way resembles a fish except in the fact that it swims; but it is, -nevertheless, the commonest name. - -Jellyfishes vary in size from that of a pinhead to six or seven -feet in diameter. They differ in the number, size, and position of -the tentacles, the number of the radial canals, the form of the -manubrium, the position of the egg-sacs, etc.; but the general plan -of the internal structure is the same in all species. In shape they -are compared to a mushroom. From the center of an umbrella-like top -falls a central organ like the stalk of a mushroom. It is called the -/manubrium/ and is the mouth and stomach of the animal. - -From the top of the manubrium radiate straight or branched tubes, -which are connected with a canal which runs around the whole margin -of the umbrella. Extending around the inner circumference of the -disk in certain species (usually the hydroid medusae), there is a -horizontal shelf, called the /velum/, or veil, because it sometimes -falls like a veil. [pg135] - -From the margin of the umbrella depend the tentacles. There are -little mineral deposits, like crystals, called /lithocysts/, disposed -at intervals on the margin, and known also as /marginal bodies/, -which are supposed to be eyes. In some species these lithocysts -are inclosed in club-shaped bodies, and they are then called -/tentaculocysts/, because they are like small tentacles. These, -together with the nerve-fibers, are called the sense-organs; but to -what extent jellyfishes can see and feel is undetermined. This is -the first appearance of sense-organs in animals. Around the concave -surface of the umbrella is a muscular zone, or zone of contractile -tissue, by which the animal opens and shuts the umbrella and gets its -locomotive power. The /gonads/, which are conspicuous from being more -opaque than the rest of the body, are the egg- or sperm-sacs. They -vary in form and in position. - -The jellyfish is carnivorous, feeding on small organisms such -as crustaceans and even fishes. The tentacles are invested with -stinging-cells, as are also the frills about the mouth, when such -occur. With these stinging-cells, which are in some species so -powerful as to have been compared with an electric battery, the -jellyfish benumbs its prey. The stinging properties are due to -nettle-like threads contained in poison-cells. When these penetrate -the flesh they produce a pain similar to that of an electric shock. - -The food is taken into the manubrium by the square mouth at its -free end, and is there digested. It is then sent as nutritive fluid -through the canal system of the body, and ejected through small pores -in the canal which surrounds the margin of the umbrella. - -There are two sexes. The gonads of the female contain eggs; those of -the male, sperms. The contents of the gonads drop into the central -cavity and pass out through the mouth. The fertilized ovum is called -a /planula/, and is a transparent sphere covered with cilia, by -means of which it swims about for a time. At length it attaches -itself to some object, and becomes in some species a branching colony -(hydroid), in other species a /strobila/. The latter, as it grows, -is constricted at intervals, and at maturity resembles a pile of -inverted saucers with lobed edges. Each of [pg136] these saucers -is finally detached, and when liberated is called an /ephyrula/, -and becomes a jellyfish. Thus its cycle of life is complete. There -are some species which, having no hydroid or strobila state, mature -without alternation of generation (/metagenesis/). - -The term of life of the jellyfish does not exceed one year. Even the -giant /Cyanea/ attains its immense growth in six months. It starts -in the spring as an ephyrula, not more than one half of an inch in -diameter, and when it dies in the autumn is often six to eight feet -in diameter. The bodies of jellyfishes are ninety-nine per cent. -water, and the dead ones thrown upon the beaches by the autumn storms -rapidly disappear, leaving no traces behind. - -The powerful stinging-cells with which the large medusae are armed -make them formidable enemies, and it is probable that some deaths -by drowning are caused by swimmers encountering them and becoming -paralyzed by them. - - -ORDER =STAUROMEDUSAE= - -("/Cross-medusae/") - - -GENUS ^Lucernaria^ - - ^L. auricula.^ This little iridescent jellyfish, which measures - about one and a half inches in diameter, is commonly found attached - to eel-grass by a stalk-like projection of the top of the umbrella. - Short, globe-tipped tentacles are arranged in eight clusters, each - cluster on a raised prolongation of the margin of the umbrella, and - in the center of each space between them is a dark kidney-shaped - organ called the /anchor/. These anchors are used for holding, - either for suspension or when moving from place to place. The - mouth forms a slight quadrangular projection in the center of the - bell-like expansion. The arm-like projections are mottled with - two rows of spots, which are the ova. Although a free form and - capable of moving about, /Lucernaria/ is sedentary in habit. It is - sometimes found free, but generally attached by its extremity to - eel-grass or /Fucus/, seldom to rocks. It is constantly changing - its shape. The one it most frequently assumes is that of a cup or - inverted bell. It is found on the New England coast. (Plate XLIV.) - - -ORDER =PEROMEDUSAE= - -("/Maimed medusae/") - - -GENUS ^Pericolpa^ - - ^P. quadrigata.^ Umbrella conical and divided by a horizontal - constriction into two parts, the lower one being again divided into - lobes. There are four long tentacles and four tentaculocysts. It is - not found on the coasts of the United States. [pg137] - - -ORDER =CUBOMEDUSAE= - -("/Cube-medusae/") - - -GENUS ^Charybdaea^ - - ^C. marsupialis.^ Umbrella square, flattened on top, and of firm - consistency. Four tentacles fall from lobes on the umbrella, and - four club-shaped eyes are in marginal notches. Plate-like egg-sacs - follow each side of the four radial canals. The bell is one inch - in diameter and about two inches in height. It is not found on the - coasts of the United States. - - -ORDER =DISCOMEDUSAE= - -("/Disk-medusae/") - - -SUBORDER ~SEMOSTOMAE~ - - -GENUS ^Aurelia^ - -[Illustration: /Aurelia flavidula/, about one fourth natural size.] - - ^A. flavidula.^ Size eight to ten inches in diameter; disk - gelatinous, transparent bluish-white, broad and comparatively flat, - with a fringe of short tentacles of even length around the margin; - margin broken by eight notches, in each one of which is a club-like - organ (/tentaculocyst/) containing calcareous spots or eyes, which - are hidden by lappets or hood-like coverings; groups of nerve-cells - also lie in the marginal notches; radial canals branched; manubrium - very short, with square mouth, which is surrounded by delicate - membranes, or oral arms, each arm being a folded membrane tapering - to a point. The edges of the membranes are covered with lasso- or - stinging-cells. Four egg-sacs, or gonads, are conspicuous in - horseshoe shape around the center of the disk. The gonads are - pink in the males, and yellow in the females. These medusae swim - in shoals, and are common everywhere in summer. They may be said - to be annual animals, for they make their appearance regularly as - free-swimming medusae in the latter part of April, when they may be - seen in immense numbers near the surface when the water is smooth - and the sky clear. At this time they are about an inch in diameter. - They grow rapidly, and by the end of June have attained their full - size. At [pg138] the end of July they are fully developed, and - begin to discharge their eggs, which go into the folds around the - mouth and remain there until they attain the planula stage. After - the spawning period the medusae, reduced in strength, are unable - to resist the storms of the autumn, and many of them are cast - ashore; many others, in a more or less wasted condition, float - near the surface, but the body is less transparent, its tissues - are thickened, its tentacles gone, and general dissolution has - commenced. In this condition the medusae are frequently capsized by - the air which accumulates in the empty egg-cavities, and, floating - helplessly on the surface, are attacked and destroyed by swarms of - small crustaceans; thus their cycle of life is terminated. It has - been suggested that the destruction of the mothers, by being cast - upon the beaches in the autumnal gales, is a provision to set free - the planulae in a position favorable to their existence; for when - liberated they fasten upon the rocks and seaweeds of the shore, - where, during the winter months, they develop into strobilae, which - in turn free their saucer-like disks early in April. - -[Illustration: Strobila of /Aurelia flavidula/.] - - -GENUS ^Cyanea^ - -[Illustration: /Cyanea arctica/, greatly reduced in size.] - - ^C. arctica^, the sun-jelly or sea-blubber. This is the largest - jellyfish known. Some individuals measure seven and a half feet - across the disk and have tentacles more than one hundred feet long. - Usually they are three to five feet in diameter, with tentacles - thirty to forty feet long. The disk is red, the margin white and - scalloped. The tentacles, of different colors, are covered with - lasso- or stinging-cells, and are arranged in eight distinct, - thick clusters on the margin. From the mouth hang four long and - very broad, thin curtains, much folded and ruffled, whose edges at - times look as if they were embroidered, because great numbers of - discharged eggs are attached to them. Four egg-sacs hang from the - disk near the manubrium, and eight sense-organs (tentaculocysts), - in hardened coverings, lie in some of the deep incisions of the - margin. /Cyanea/ [pg139] is usually solitary, seldom being seen - in company with others. It is common on the New England coast, - and is frequently found stranded on the beach, where it in no way - suggests the beautiful appearance it presents when floating in - the water. Like /Aurelia/, /Cyanea/ has a strobila stage. It is - supposed that the young remain near the bottom, for they are seldom - seen, while adults are plentiful. They begin to appear in numbers - at the end of summer from Cape Cod northward. - - ^C. fulva.^ This species is found in midsummer south of Cape Cod - and is common in Long Island Sound. Its general color is light - yellowish-brown, the flowing curtains being the darkest part of - the animal. It is not as large as C. arctica, and the lobes of the - margin are deeper and more rounded. - - ^C. versicolor.^ The whole disk is bluish milky-white, the flowing - curtains are light brown, and the tentacles are pink. It is not so - large as /C. arctica/. Found in the spring on the southern coast. - -[Illustration: /Linerges mercurius/, thimble-fish.] - - -GENUS ^Linerges^ - - ^L. mercurius^, the thimble-fish. The English name indicates the - form as well as the size of this little brownish jellyfish, which - is found near the Florida Keys, extending in lines for considerable - distances. - - -GENUS ^Pelagia^ - - ^P. cyanella.^ Umbrella spherical, margin scalloped, tentacles - eight in number; four long appendages ruffled on the edges hang - from the mouth; size about two inches in diameter; appendages four - inches long; color pink. (See next page.) - - -SUBORDER ~RHIZOSTOMAE~ - -The =Rhizostomae=, or root-mouth jellyfishes, are very remarkable. -They have no tentacles, but covering the end of the manubrium and -hanging from it like tentacles are oval appendages with numerous -minute funnel-like apertures, called suctorial mouths. As the manner -of locomotion of jellyfishes is peculiar to themselves, so also is -this many-mouthed development unique in the animal kingdom. The -type of this group, described below, is found on the Florida Keys. -The different species vary in diameter from three to eight inches. -[pg140] - - -GENUS ^Cassiopeia^ - -[Illustration: /Pelagia cyanella./] - - ^C. frondosa.^ This species has a circular disk, on the margin of - which are sixteen sense-organs (tentaculocysts), but no tentacles. - The lower end of the manubrium, which in other jellyfishes is - an open mouth, is closed by eight arms which emanate from it - and are usually extended laterally, lying parallel to the disk. - These arms are much branched, and the branches, in turn, have - numerous appendages. Some of these appendages look like little - polyps and have mouths surrounded by crowns of tentacles; others - are ovoid bodies without external openings, but with a central - cavity connected with vessels leading to the arms. The former are - mouths, but the function of the ovoid bodies is not known. Although - able to swim freely, /Cassiopeia/ lies usually on its back, as if - attached, and languidly opens and closes its disk, rarely changing - its position. Its arms, extending upward, appear like the fronds of - algae. These jellyfishes are common on the Florida coast, huddled - together on the sands of the coral reefs. (Plate XLIV.) [pg141] - - -TABLE SHOWING THE CLASSIFICATION OF THE ACTINOZOA DESCRIBED IN THIS -CHAPTER - - Class =ACTINOZOA= - - Subclass =Zoantharia= (/Mesenteries numerous, usually in - multiples of six; tentacles unbranched hollow cones/) - - Order =ACTINIARIA= (/The sea-anemones. Single; no skeleton/) - - Genera Species - - ^Metridium^ ^M. marginatum^ - ^Rhodactinia^ ^R. davidsii^ - ^Holocampa^ ^H. producta^ - ^Sagartia^ ^S. leucolena^ - - Order =MADREPORARIA= (/The stone- or reef-corals. Colonies; - skeleton calcareous/) - - ^Oculina^ - ^Astraea^ - ^Meandrina^ - ^Diploria^ ^D. cerebriformis^ - ^Madrepora^ ^M. cervicornis^ - ^M. palmata^ - ^Astrangia^ ^A. danae^ - - Order =ANTIPATHARIA= (/The black corals/) - - Subclass =Alcyonaria or Halcyonoida= (/Tentacles and mesenteries - eight in number; tentacles feathered, that is, with uniform - branches/) - - Order =ALCYONACEA= - - ^Alcyonium^ ^A. palmatum^ - ^Tubipora^ - - Order =GORGONACEA= (/The sea-fans and sea-whips. Compound, - tree-like colonies, with horny axis, branching throughout/) - - Order =PENNATULACEA= (/Free, phosphorescent; colonies, with - horny axis; polyps in lateral branches/) - - ^Pennatula^ - -[pg142] - - - -CLASS =ACTINOZOA= - -SEA-ANEMONES, REEF-CORALS, SEA-FANS, SEA-WHIPS, AND SEA-PENS - - -The animals of this class are divided into two subclasses, based on -the following anatomical differences: In the first subdivision, which -includes the sea-anemones and the reef-building corals, the polyps -have numerous simple, hollow tentacles and radial partitions of the -same number, both being some multiple of six. The polyps of a colony -are all alike, and the hard matter they secrete is carbonate of lime. -In the second subdivision, the /Alcyonaria/,--or halcyonoids, as they -are commonly called,--the tentacles and radial partitions are always -eight in number, and the tentacles have small symmetrical appendages -or branches. The polyps of this group are often accompanied by -small zooeids having no tentacles. The hard secretions are horny -and elastic, as in sea-fans, sea-whips, and sea-pens, or they are -extremely hard, as in /Corallina rubrum/. - - - - -SUBCLASS =ZOANTHARIA= - -("/Animal-flowers/") - - -ORDER =ACTINIARIA= - -SEA-ANEMONES - -These curious and, at times, beautiful creatures are polyps, and are -constructed on the radial system. They have a cylindrical body with -a broad base and rows of hollow tentacles around the upper disk. -They have a central sac, and a space between the outer and inner -sacs which is divided vertically by walls called /mesenteries/, as -explained on page 114. Each tentacle, however many there [pg143] may -be, has a corresponding chamber. The inner sac has a mouth, like a -slit, at the top of the disk, opening to the outside, and it also has -openings into the chambered spaces which surround it. These chambers -also open into the hollow tentacles; thus a continuous circulation -throughout the whole animal is established. - -The food taken in at the mouth is digested in the inner sac, passes -through all the chambers of the cavity as nutritive fluid, and is -then expelled at the mouth again. The inner sac, or gullet, has -longitudinal grooves; two of these are broad and deep, and correspond -to the corners of the mouth. These are called /siphonoglyphs/. The -sea-anemone is soft and contractile, and belongs to the only order -of this class which does not secrete a skeleton. It has two sets of -muscles, one of which extends from the base to the summit of the body -and is placed on the dividing partitions. Sea-anemones are classified -by the arrangement of the septa and the manner in which the muscles -are placed upon them. The other set of muscles is arranged around -the circumference of the column or body. Each tentacle is furnished -with similar sets of muscles. The animal is sensitive, and at the -least alarm contracts its body by means of these muscles, and -quickly transforms itself from a beautiful, flower-like form into a -shapeless, unattractive, inconspicuous mass. - -The /Actiniaria/ are developed from the egg. The eggs form on the -edges of the inner walls (mesenteries), and when mature drop into -the outer sac (gullet), and out of the mouth as ciliated spheres -(planulae). After swimming about for a time these attach themselves to -rocks, and, conforming to the irregularities of the surface, secure a -tight hold. The upper surface of the planula then becomes depressed -and forms a gullet, and in time a complete animal is formed. The -/Actiniaria/ reproduce also by budding. A small protuberance or -simple elevation of the body-wall appears on the side at the base, -or in some species on the disk of the animal, which generally -develops into a complete animal and at maturity falls away from the -parent. Sometimes several anemones bud simultaneously from the same -individual, and a third generation commences to bud at the same -time from the immature young of the parent stock. The sea-anemones -increase [pg144] also by self-division. In this case a constriction -is formed, which gradually deepens and forms a complete partition of -the body, and two individuals exist where originally there was but -one. - -The /Actiniaria/ are carnivorous and very voracious. They feed -on small organisms and on shell-fish and crustaceans, which they -suck out of their shells. To secure their prey they are armed with -an abundant supply of stinging-cells on the tentacles, and also -with fine stinging-threads which are ejected from pores which are -distributed over the whole body. - -Sea-anemones vary greatly in color and form, and when expanded -suggest flowers, but do not resemble the one for which they are -named. They abound on every shore, the same genus often being found -in widely separated regions. They are larger and more highly colored -in tropical waters. Many of the species are littoral, and are found -in the tide-pools of rocky caverns, on the under side of rocks, and -on the piles of wharves and bridges at low-water mark. The majority -of them are attached, but are able to change their location; others, -/Edwardsia/ and /Cerianthus/, swim about when young, and in the -adult state burrow in the sand or mud, leaving only their tentacles -exposed. /Bucidium parasiticum/ is parasitic on the folds of the -membrane which hangs from the mouth of the large jellyfish /Cyanea -arctica/. /Fenja/ and /Peachia/ lie on the sea-bottom, with their -bodies horizontal like a worm, the mouth-end and tentacles erect. - -/Adamsia palliata/ furnishes another example of commensalism; it -lives on the back of shells, commonly the whelk, inhabited by -hermit-crabs. /Minyas/ is pelagic; it has a float at one end, and by -means of its tentacles swims about freely. - -A very few species only are described below, since these polyps are -unmistakable, being always columnar bodies, with the upper disk more -or less crowded with tentacles, and so brilliant in coloring and -beautiful in form as to attract attention if found in the expanded -state; otherwise they are easily overlooked. - - -GENUS ^Metridium^ - - ^M. marginatum.^ This is the most conspicuous and abundant - sea-anemone of the northeastern coast. It is common from New York - [pg145] northward, and is found near low-water mark in tide-pools, - on the under side of large stones, in sheltered crevices of rocks, - and on the piles of wharves and bridges. In contraction it is a - broad, low cone, but when expanded is sometimes ten inches across - the disk. Allied species found in Florida are eighteen inches in - diameter. The column is smooth, cylindrical, and broader than - long. At the top is a slightly elevated, thickened fold, and - above this a deeply folded and frilled margin, with numerous - fine, short tentacles, appearing like a fringe, which cover the - upper side of the disk half-way to the oval mouth. The color is - exceedingly variable; commonly the column is yellowish-brown, but - it may be pink, white, salmon, orange, or dark brown, or striped - or mottled with different colors. The disk and folds are lighter - or flesh-colored, and the tentacles are of varying colors, usually - grayish with tips of brighter colors. When irritated this species - throws out from the column numbers of long, slender white threads - (/acontia/), which are covered with minute stinging-cells. These - organs of defense protect the animal from the attacks of many - enemies. - - -GENUS ^Rhodactinia^ - - ^R. davidsii^ (Agassiz), ^Tealia crassiformis^ (Gosse), the - thick-petaled rose-anemone. The color varies, being often - bluish-green mottled with crimson, often bright cherry-red, with - the thick tentacles somewhat lighter in shade, or flesh-colored. - The animal is found in shallow water. It assumes various shapes, - changing every few minutes. The tentacles are short, conical, and - uniform in size; the column, the breadth of which is greater than - its height, often has wart-like processes in longitudinal lines. - The diameter of the disk is about three inches. Found from Cape Cod - northward in tide-pools and on ledges covered with /Fucus/. - - -GENUS ^Holocampa^ - - ^H. producta.^ Its column, stretched to its full extent, is a foot - in length and about an inch in diameter, but when contracted is - much shorter and thicker. It has but twenty tentacles, and these - have swollen tips. Rows of suckers extend the length of the column. - It ranges from Cape Cod to South Carolina, and is found under rocks - at low-tide mark, and also on sandy beaches, buried in the sand, - with its tentacles only above the surface. - - -GENUS ^Sagartia^ - - ^S. leucolena^, the white-armed anemone. It ranges from Cape Cod - to North Carolina, and is common in Long Island Sound, being found - at low-water mark on the under side of stones. The column is - elongated, cylindrical, translucent, flesh-colored, with simple - plain disk and long, slender, whitish tentacles crowded together - near the margin. [pg146] - - -ORDER =MADREPORARIA= - -STONE- OR REEF-CORALS - -The coral resembles the sea-anemone and is a polyp constructed on the -radial plan (page 113). It lives in colonies, but, unlike the hydroid -colonies, each polyp of the community is a complete organism, and -in the reef-building corals all the individual polyps of a colony -are alike. The home of each animal is called a /corallite/, and the -aggregation of many corallites is a /corallum/. - -The corallite is composed of carbonate of lime secreted by the polyp, -and, broadly speaking, may be called a skeleton. The secretion forms -a basal plate and radiating partitions between the mesenteries in -the cavity of the animal, and also surrounds the polyp like a cup. -In some species this is a solid substance; in others it is like a -network through which the animal substance (c[oe]nosarc) of the -zooeids of the colony is connected, as in /Madrepora/. - -The polyps reproduce by budding and by self-division (fission), -in a manner similar to that of sea-anemones. The way in which the -budding or the fission takes place determines the shape of the -colony, or corallum, which has a great variety of forms. In some -species the budding is confined to certain individuals of the colony. -In this case the branched forms result. When growth takes place by -fission, hemispherical masses are formed, which are often perfectly -symmetrical, as in the so-called brain-corals. In /Astraea/ the polyps -are inclosed separately, but in /Meandrina/ fission is confined to -the upper half of the polyps, so that a complex polyp is formed, with -several mouths opening into a common stomach, making long serpentine -furrows on the corallum. - -Some of the genera of the second subdivision, the alcyonarians, -differ materially from the ordinary idea of corals, as their -framework is of a horny and more or less flexible material (chitin). -Of these are the sea-fans, sea-whips, and sea-pens. The organ-pipe -coral of the same subdivision is an example of an exceedingly -fragile lime structure, while the red coral, /Corallina rubrum/, -[pg147] the species so much used for ornamental purposes, has an -exceedingly hard and stony character. The madrepore corals are called -reef-builders, but not in the sense of constructors of reefs. They do -not erect definite structures as bees do. It is the aggregation of -the skeletons of the dead polyps, together with other agencies, which -forms a reef. The coral polyps, though so minute individually, are -almost infinite in numbers. It is estimated that the colonies rise -one half of an inch in ten years. - -Corals live at different depths in the sea. Those which form the base -of the reef are the astraeans, which do not live above a depth of six -fathoms. They are characterized by little star-shaped spots on the -corallum, the radial partitions meeting in the center of the spots, -or corallites. Next above the astraeans come the maeandrinas and the -porites. The former have elongated openings which extend in waving -furrows over the surface. The porites resemble astraeans, but the pits -are smaller, with fewer partitions, and the substance is more porous. -Above these and capping the reefs are the beautiful branching and -palmate madreporians, together with millepores, numerous varieties of -sea-fans (/Gorgonacea/), and the calcareous seaweeds (nullipores), -making a garden of beautiful branching forms of every shape and color. - -The coral reef is as thickly inhabited by other living organisms -as is the forest by birds and insects. Mollusks, worms, crabs, -starfishes, and sea-urchins find resting-places there and work -destruction to the coral masses, as they bore and penetrate the reef -in various ways until large fragments of it are detached and either -washed by the waves to places far from their foundation, or ground -to sand, which, filling the interstices of the reef, adds to its -solidity. - -The living coral is quite different in appearance from the bleached -skeletons commonly seen. The surface of the corallum is often soft -and downy, from the numerous waving tentacles, and its coloring is -vivid and varied. The madrepores are pink, yellow, green, brown, and -purple. /Tubipora/, the organ-pipe coral, has green polyps emanating -from its red tubes. White polyps in star-like form dot the branches -of the red coral of commerce, /Corallina rubrum/. The whole mass -of /Helipora/ is bright blue, [pg148] and the beautiful sea-pens -are both highly colored and phosphorescent. Owing to the fact that -these brilliantly colored polyps were mistaken for blossoms, the -recognition of their true character was long delayed, they having -been ranked as vegetables until comparatively recent times. - -With few exceptions, corals do not grow in water below the -temperature of 68 deg., hence they are inhabitants of tropical and -subtropical waters. The Florida Keys are coral reefs, and the species -described below are to be found there. - - -GENUS ^Oculina^ - -Arborescent; corallites arranged somewhat spirally on branches and -widely separated; branches compact between corallites. Each bud is -for a time at the apex of the branch, but finally becomes lateral, -and then gives off another bud from its upper surface, and so the -stem lengthens. (Plate XLIV.) - - -GENUS ^Astraea^ - -The star-corals. The corals of this genus are hemispherical masses -covered with small star-shaped pits, or corallites. Although the -diameter of an astraea-dome may be twelve feet or more, it has only -one half or three quarters of an inch of living coral on its surface, -the rest being solid matter left behind as the polyps rose in growth. -The colony increases by self-division. The septa meet in the center -of the corallite, making star-like pits; the surface is comparatively -smooth. (Plate XLIV.) - - -Genera ^Meandrina^, ^Diploria^ - -Corallum massive, hemispherical in shape, with furrows running in -irregular lines over the whole surface. The peculiar serpentine form -of the corallite is produced by the animal growing in one direction, -fission being incomplete, and new mouths being successively opened -until a line of them extends along a common stomach. - - ^D. cerebriformis.^ This species is commonly known as brain-coral - or brain-stone. The hemispherical shape, together with the peculiar - serpentine corallites, makes its resemblance to the human brain - very noticeable and the name unusually appropriate. This species, - when living, is bright yellow. (Plate XLV.) - -[Illustration: PLATE XLIV. Millepora alcicornis. Lucernaria auricula. -Cassiopeia frondosa. Astraea argus. Oculina.] - -[Illustration: PLATE XLV. Porites furcata and P. astraeaoides. Diplora -cerebriformis. Madrepora cervicornis. Madrepora palmata. Mycedium -fragile.] - - -GENUS ^Madrepora^ - -Some species of these corals appear like branches, while others -have flat, low surfaces or fronds; all of them are covered with -innumerable small cylindrical cups. Each cup is the home of a polyp, -which secretes calcareous matter around its column, and septa between -its radial partitions. The corallum, when examined with a glass, -looks like meshwork. Through the fine openings of the porous surface, -the polyps of the colony are connected by interlacing tubes of animal -substance (c[oe]nosarc). The polyps of the madrepore colonies are -small in comparison with the connecting structure, which becomes very -massive; but, although large, the corallum is fragile, on account of -its perforated character and the exceeding delicacy of its parts. - -In species which form incrustations, new polyps arise from tissue -which spreads beyond the corallites. In some species certain polyps -and corallites increase in length, growing longitudinally, and -continually form buds around the base. This manner of growth leads -to the formation of branches, while the former manner gives lateral -extension. Both of these forms of budding may take place at the same -time in the same colony. The madrepores are among the most common of -the reef-builders. They form reefs which extend for miles around the -Florida Keys. - - ^M. cervicornis^, the stag-horn coral. This is a branching species - which attains large size. Its manner of growth is as follows: At - the tip of each branch is an individual polyp, which is larger - than those which surround the branch. This is the original animal - which started the branch, and is the parent from which all the - others on the branch have budded. The large terminal polyp buds - around the base; a surplus of lime also collects at the base and - clogs its tissues, so that it no longer can perform the functions - of life, and after a certain period the base becomes dead matter. - The polyp on the upper end continues to live and rises above the - excess of solid matter. At the same time it continues to form new - buds. The buds become independent corallites and secrete an excess - of calcareous matter at their bases, which cements them to the - parent stock and increases the thickness of the branch. Thus, as - the original polyp constantly rises and buds, the colony assumes a - stem-like form, covered with numerous individuals. Certain polyps - on the main stem have the attributes of the parent animal. These - start branches, and so the process goes on, and in time the colony - becomes much branched and arborescent in form. In the living coral - each little polyp is like a minute sea-anemone, having a colored - cylindrical body surrounded on its upper disk with numerous - tentacles. (Plate XLV.) [pg150] - - ^M. palmata.^ This madrepore grows like the one described above, - except that the branches do not remain separated, but unite or grow - together, giving broad, flat surfaces which resemble fronds. When - carefully examined these surfaces show striations which indicate - the course of the branches. The structures forming the lobes are - caused by the failure of the branches to unite. On the Carysfort - Reef of the Florida Keys this species covers the top of the reef - for several miles, nearly reaching the surface, and appears like a - vast bed of low yellow shrubbery. (Plate XLV.) - - -GENUS ^Astrangia^ - - ^A. danae.^ A small coral found on the New England coast. It lives - in the clefts of rocks in small patches, sometimes two to three - inches across and one quarter of an inch or more high. Frequently - it is like a thin crust of lime covered with star-like divisions. - Sometimes it forms branches. The living animals are white, and - when expanded rise above the cells and resemble a cluster of small - sea-anemones. - - -SUBCLASS =ALCYONARIA= or =HALCYONOIDA= - -[Illustration: /Alcyonium palmatum/: /A/, entire colony; /B/, -spicules.] - -In this subclass--the actinoid corals--the polyps are of two kinds. -The smaller are without tentacles and are called /siphonozooeids/. The -larger have but eight radial partitions and eight tentacles. This -limitation of parts places them in a higher rank than the corals of -the first subclass. Another characteristic of these polyps is the -presence of symmetrical branchlets on the tentacles, which give them -a feather-like appearance. These corals are called halcyonoids. -[pg151] - -Some of them may easily be fancied to have been selected for -halcyons' nests, as the name suggests--the sea-fans, for example. - - -ORDER =ALCYONACEA= - - -GENUS ^Alcyonium^ - - ^A. palmatum.^ This coral community is found sometimes at low-water - mark, but usually in deeper water, attached to shells and stones. - It is commonly known as dead-men's-fingers, an unpleasant name - given it by fishermen because of a fancied resemblance to a human - hand with only the stumps of the fingers. The substance of the - coral is semi-cartilaginous, with scattered spicules of lime which - give it stability. When the polyps are fully extended the colony - is rather attractive in appearance, but not so when contracted. - It is found in abundance on the New England coast. An immense - /Alcyonium/, /Paragorgia arborea/, grows on the fishing-banks off - Newfoundland, and is sometimes brought up on the fishing-lines. It - is tree-like in form, and measures six feet or more in length. - - -GENUS ^Tubipora^ - -[Illustration: /Tubipora/, organ-pipe coral, natural size.] - -The organ-pipe coral. This genus, which is deep red in color and very -fragile, consists of many tubes slightly separated from [pg152] one -another, but connected by horizontal platforms at short intervals. -The form of reproduction, by budding, in this colony is peculiar to -itself. The spicules of lime secreted in the polyp unite or fuse into -a tube or cylindrical skeleton. At certain stages of development -the polyp sends out a horizontal expansion, which unites with the -expansions of other polyps and becomes calcified, forming a shelf -which binds the tubes together. From the top of the platforms other -corallites are formed, and thus a colony is made, which broadens as -it rises in its growth. The body of the polyp is green, the skeleton -red. It belongs to the East Indian seas and is given here only as an -example of a peculiar manner of growth. - - -ORDER =GORGONACEA= - -SEA-FANS, SEA-WHIPS, AND SEA-FEATHERS - -These are compound, tree-like /Alcyonaria/, with a calcareous or -horny skeleton which forms a branched axis and is covered with a -layer of united polyps having spicules of lime distributed through -the mass, which give some firmness to the bark-like covering. -Gorgonias, in great variety, grow in abundance on the coral reefs and -mud-flats of Florida, forming masses of low shrubbery, pink, yellow, -brown, or purple in color. - -The sea-whips and sea-feathers are varieties of gorgonias, which are -named from their forms. Some have shapes which resemble branching -shrubs; others are long unbranched rods, either straight or spiral. -They attain a height of several feet and are of various colors. The -colony has a horny axis surrounded by a living mass which resembles a -sheet of animal matter. This mass consists of polyps closely united, -and has throughout its substance spicules of carbonate of lime, -making it a kind of calcareous crust or bark. In dried specimens -this becomes very brittle, and is easily broken from the horny axis. -(Plates XLVI, XLVII.) - -[Illustration: PLATE XLVI. GORGONIAS. - -Eugorgia aurantica. Muricea specifera. Pterogorgia acerosa. Gorgonia -anceps.] - -[Illustration: PLATE XLVII. Leptogorgia rigida (a gorgonia). Eunicea -lugubris (a gorgonia). Gorgonia flabellum (a gorgonia). Leptogorgia -Agassizii (a gorgonia). Pennatula borealis and P. aculeata -(sea-pens).] - -The sea-fans are colonies with a central, horny, flexible, and -much-branched axis, covered, as in the sea-whips, with a layer of -united polyps containing spicules of lime, which make a somewhat -[pg153] firm crust. This, in dried specimens, breaks off readily. -The colony branches profusely, or rather separates by fission, in -one plane, the large and small branches making a network of fan-like -shape and often of great fineness and intricacy. These fans attain a -length of several feet and a corresponding breadth, and are abundant -in semi-tropical as well as in more southern waters. In color they -are red, yellow, brown, or purple. - - -ORDER =PENNATULACEA= - -SEA-PENS - -These singular colonies resemble quill-feathers, such as are used for -pens, and are named for this reason. The long, horny central axis is -naked below, and is partly buried in the sand, but is not permanently -attached. The upper portion of the axis has two rows of short, -opposite, lateral branches; on the upper side of the branches the -polyps live in separate inclosures. Spicules of lime are present in -the substance of the branches, which gives them stability. Sea-pens -are found at moderate depths and are widely distributed. They are -highly colored and phosphorescent. [pg154] - - -TABLE SHOWING THE CLASSIFICATION OF THE CTENOPHORA DESCRIBED IN THIS -CHAPTER - - Class =CTENOPHORA= - - Order =CYDIPPIDA= (/Two tentacles, retractile into sheaths/) - - Genera Species - - ^Pleurobrachia^ ^P. rhododactyla^ - - Order =LOBATA= (/Numerous lateral tentacles contained in a groove; - body compressed; two large oral lobes/) - - ^Bolina^ ^B. alata^ - ^B. septentrionalis^ - ^B. vitrea^ - - ^Mnemiopsis^ ^M. Leidyii^ - - Order =CESTIDA= (/Ribbon-like form, from body being extremely - compressed in the vertical plane/) - - ^Cestum^ ^C. veneris^ - - Order =BEROIDA= (/No tentacles; mouth very wide; gullet occupies - greater part of body/) - - ^Idyia^ ^I. roseola^ - ^I. cyanthina^ - -[pg155] - - - - -CLASS =CTENOPHORA= - -COMB-JELLIES - - -These are delicate, free-swimming, generally spherical bodies, -resembling jellyfishes in outline, transparency, and gelatinous -consistency, but differing from them widely in the manner of -locomotion. They are called "comb-jellies" from the rows of flat -cilia, arranged like the teeth of a comb, which run in eight -meridional lines over the surface. It is by means of these cilia -that the animal moves through the water. The little paddles are -worked in unison, in single lines, or each one of them can be -moved independently, and they give the animal varying and peculiar -motions. The /Ctenophora/ are nearly transparent, but have a -prismatic coloring, caused by the waving cilia, and at night they are -phosphorescent. They are widely distributed, being found in all seas. - -The mouth of the animal opens into a gullet which extends two thirds -through the length of the body. On each side of the gullet is a -vertical tube. The two tubes unite at the base of the gullet, and -from there run as a single canal to the end opposite the mouth, and -open to the outside through two excretory pores. From the base of -the gullet, where the tubes unite, two other tubes extend laterally, -which divide and subdivide in a horizontal plane, becoming eight in -number, and connect at the surface with the lines of cilia; then, -dividing, run in opposite directions to the poles of the spherical -body. The animal derives its nourishment and air through this -circulatory system. A nervous system is situated at the pole opposite -the mouth, in a small area surrounded by cilia, in the center is an -eye-speck, or lithocyst. [pg156] - - -ORDER =CYDIPPIDA= - - -GENUS ^Pleurobrachia^ - -[Illustration: /Pleurobrachia rhododactyla/, in motion.] - - ^P. rhododactyla.^ A transparent spherical body, one inch to one - and a half inches in diameter, with eight combs or plates of flat - cilia extending from pole to pole. At one pole is the mouth, like - a slit, at the other a small area in the center of which is an - eye-spot. From the body hang two tentacles, half a yard or more - in length, fringed with cilia. The tentacles are very contractile - and can be rolled up or expanded with great rapidity; they take - graceful curves as the animal moves rapidly through the water. - /Pleurobrachia/ has a pink tint, and prismatic colors play over - it from the vibrating cilia. It is a beautiful and interesting - creature to watch. Found along the shores of Massachusetts and - Maine. - - -ORDER =LOBATA= - - -GENUS ^Bolina^ - -[Illustration: /Bolina alata/, seen from the broad side: /o/, -eye-speck; /m/, mouth; /r/, auricles; /v/, digestive cavity; /g/, -/h/, short rows of flappers; /a/, /f/, long rows of flappers; /b/, -/n/, /x/, /t/, /z/, tubes winding in the larger lobes; /i/, base of -gullet. About half natural size.] - - ^B. alata.^ Slightly oval in form; lower part of the body divided - into two large lobes which hang below the mouth. Four of the - swimming-plates are shorter than the other four and terminate in - curious processes or short appendages called auricles. /Bolina/ - is about two inches in length, and is very delicate, transparent, - and phosphorescent. Its contractile power enables it to vary in - outline to a considerable extent. It has a slow undulating motion, - and sometimes carries its lobes uppermost and open. Usually found - associated with /Pleurobrachia/ from Massachusetts northward. - - ^B. septentrionalis.^ Found on the northern Pacific coast. - - ^B. vitrea.^ A species found in Florida. [pg157] - - -GENUS ^Mnemiopsis^ - - ^M. Leidyii.^ Resembles /Bolina/ in general form; often six to - eight inches in length; gregarious, thousands often being collected - together; exceedingly phosphorescent. - - -ORDER =CESTIDA= - - -GENUS ^Cestum^ - - ^C. veneris^, Venus's girdle. This singular animal, although not - an inhabitant of our seas, has its place in this group, and is - shown here because of its very curious shape. In form it is flat - and ribbon-like. Sometimes it attains a length of five feet, while - in breadth it is but one or two inches. The mouth is midway in its - length and is opposite the sense-organ or eye-spot. On each side of - the mouth is a short tentacle which protrudes from a sac. Four of - the swimming-plates are small; the other four extend along the edge - of the body. /Cestum/ moves by contractions of the body more than - by the combs which fringe its edges. It is very transparent, with - a violet hue, and is so delicate that it is difficult to capture - it uninjured. Its habitat is the Mediterranean Sea. It may be seen - among the zooelogical specimens in almost any museum. - -[Illustration: /Cestum veneris./] - - -ORDER =BEROIDA= - - -GENUS ^Idyia^ - - ^I. roseola.^ This species has an ovate body three to four inches - in height and about half as broad. Some individuals are larger. - It has [pg158] an eye-spot on the upper rounded side, and at - the other end a very large mouth opening into a digestive cavity, - which occupies the greater part of the body. A delicate fringe - surrounds the area about the eye-spot, and eight rows of cilia - run from there to the oral end. It has no tentacles. /Idyia/ is - pink and especially highly colored at the spawning-time. Like - other jellyfishes, their part in life is finished when they have - discharged their spawn, and the first September storms break them - to pieces. In July and August they are plentiful on the New England - coast. They appear at the surface of the water in the hottest part - of the day, but disappear entirely when the water is in the least - rough or the weather is cold or the sun overcast. Their movements - are slow and graceful, the long axis being carried in a nearly - horizontal position. They are exceedingly voracious, feeding - chiefly on other /Ctenophora/, and often swallowing animals as - large as themselves. - - [Illustration: /Idyia roseola/, half natural size: /d/, /e/, /f/, - /g/, /h/, rows of locomotive flappers.] - - ^I. cyanthina.^ This species, found on the northern Pacific coast, - broadens near the center, making it somewhat vase-shaped. /Idyopsis - Clarkii/, a similar genus, found in Florida, is globular. All these - species are very beautiful, the rapid movement of the cilia giving - them a brilliant iridescence. - - - - -III - - WORMS - (PLATYHELMINTHES - NEMATHELMINTHES - ANNULATA) - - -TABLE SHOWING THE CLASSIFICATION OF THE WORMS DESCRIBED IN THIS -CHAPTER - - Phylum =PLATYHELMINTHES= - - Class =TURBELLARIA= - - Order ~POLYCLADIDA~ - - Genera Species - - ^Planocera^ ^P. nebulosa^ - ^Stylochopsis^ ^S. littoralis^ - ^Leptoplana^ ^L. folium^ - - Order ~TRICLADIDA~ - - ^Planaria^ ^P. grisea^ - ^Procerodes^ ^P. frequens^ - ^Bdelloura^ ^B. rustica^ - ^B. candida^ - ^Fovia^ ^F. Warrenii^ - - Order ~RHABDOC[OE]LIDA~ - - Class =TREMATODA= (/External and internal parasites/) - - Class =CESTODA= (/Internal parasites/) - - Class =NEMERTINEA= - - ^Tetrastemma^ ^T. arenicola^ - ^Nemertes^ ^N. socialis^ - ^N. viridis^ - ^Meckelia^ ^M. ingens^ - ^M. rosea^ - ^Cerebratulus^ ^C. angulatus^ - ^Cosmocephala^ ^C. ochracea^ - ^Polina^ ^P. glutinosa^ - - Phylum =NEMATHELMINTHES= - - Class =NEMATODA= - - ^Pontonema^ ^P. marinum^ - - Phylum =ANNULATA= - - Class =CHAETOPODA= - - Subclass =Polychaeta= - - Order ~ERRANTIA~ - - Families Genera Species - - ~SYLLIDAE~ - - ~APHRODITIDAE~ ^Polynoe^ ^P. squamata^ - ^P. sublevis^ - ^Harmothoe^ ^H. imbricata^ - ^Aphrodite^ ^A. aculeata^ - - ~PHYLLODOCIDAE~ ^Phyllodoce^ ^P. gracilis^ - - ~NEREIDAE~ ^Nereis^ ^N. virens^ - ^N. pelagica^ - ^N. limbata^ - - ~NEPHTHYDIDAE~ ^Nephthys^ ^N. ingens^ - ^N. picta^ - - ~EUNICIDAE~ ^Marphysa^ ^M. sanguinea^ - ^Diopatra^ ^D. cuprea^ - ^Arabella^ ^A. opalina^ - ^Lumbriconereis^ ^L. tenuis^ - - ~GLYCERIDAE~ ^Glycera^ ^G. americana^ - ^G. dibranchiata^ - - Order ~SEDENTARIA~ or ~TUBICOLA~ - - Families Genera Species - - ~SPIONIDAE~ ^Nerine^ ^N. agilis^ - ^N. coniocephala^ - - ~CIRRATULIDAE~ ^Cirratulus^ ^C. grandis^ - - ~TEREBELLIDAE~ ^Thelepsus^ ^T. cincinnatus^ - ^Amphitrite^ ^A. ornata^ - ^Polycirrus^ ^P. eximius^ - ^Ch[oe]tobranchus^ ^C. sanguineus^ - - ~AMPHICTENIDAE~ ^Cistenides^ ^C. Gouldii^ - - ~MALDANIDAE~ ^Clymenella^ ^C. torquata^ - ^Maldane^ ^M. elongata^ - - ~ARENICOLIDAE~ ^Arenicola^ ^A. marina^ - - ~SABELLIDAE~ ^Sabella^ ^S. microphthalma^ - - ~SERPULIDAE~ ^Serpula^ ^S. dianthus^ - ^Spirorbis^ ^S. borealis^ - - Subclass =Oligochaeta= (/Mostly terrestrial or fresh-water - forms/) - - Class =GEPHYREA= - - Order =SIPUNCULOIDEA= - - Genera Species - - ^Sipunculus^ ^S. nudus^ - ^Phascolosoma^ ^P. Gouldii^ - - Class =HIRUDINEA= (/Leeches/) - -[pg163] - - - - -WORMS - - -Burrowing in sand and mud, lying under stones and in crevices of -rocks, concealed in various kinds of tubular cases which are free or -attached to stones or shells, crawling over the ground or seaweeds, -swimming free or attached to other animals, is found in abundance a -class of animals commonly known as "worms," and generally regarded as -repulsive creatures unworthy of attention. - -To the biologist, however, worms are among the most interesting forms -of lower animal life. The amateur collector, if he stops to give -them careful consideration, will probably find them unexpectedly -interesting, and will be surprised to find how many varieties of them -there are, and how different they are from his preconceived notion of -them. Worms are varied in structure, their habits are strange, and -their form and color often beautiful. Although plentiful, they are -not conspicuous, but are easily found if search is made for them, and -so large a class of shore animals should not be passed by unnoticed. -Unusual biological interest is attached to this group because, in the -different types, affinities with other classes of animals are found, -suggesting, perhaps, connecting-links with higher organizations. -They are the first animals to show definite bilateral symmetry, or -two similar sides, and to carry the same part of the body always in -front. Formerly one division, called /Vermes/, comprised all the -worms. To-day they are separated into four divisions, or phyla. The -most careless observer easily recognizes the basis of separation, for -the flatworms, the round- or threadworms, the wheel-like animalcules, -and the jointed worms have very obvious differences. The names given -the phyla express these distinctions, the termination [pg164] -meaning "worm"; the prefixes /Platy-/, /Nemat-/, /Troc-/, meaning -"flat," "thread," "wheel," respectively; while /Annulata/, meaning -"ringed," describes the segmented forms belonging to that phylum. - -There are vast numbers of parasitic worms, which live internally or -externally on their hosts, there being no animal of land or sea, of -high or low degree, which is not subject to the affliction of these -visitors. The parasitic worms are degenerate, some being without -digestive organs, or without eyes, or without locomotor organs, and -so on, as the case may be, the host supplying the missing function. -The life-history of these low forms is interesting; but parasitic -worms do not come within the scope of this book, and are mentioned -only to mark their place in the series. - - -PHYLUM =PLATYHELMINTHES= - -FLATWORMS - -The flatworms have a flattened body, more or less compressed in the -different classes. Ordinarily the body is very thin, and, when short, -has a leaf-like form; when long it is ribbon-like. Some species are -thick in the middle and thin at the edges. They have a dorsal, or -upper, and a ventral, or under, surface; a right and a left side; an -anterior and a posterior end. The anterior end is carried forward and -has some of the characteristics of a head, though a distinct head is -not apparent. The mouth is on the ventral surface. In some species it -is in the middle of the length of the body; in others it is before or -behind this point. - -The flatworms are the first animals to assume pronounced bilateral -symmetry. They are soft-bodied, having no supporting skeleton, and -they have no segments, or divisions, such as are found in higher -types, as in /Annulata/. They have no body-cavity, the space -between the organs and the body-wall being filled with tissue. The -alimentary canal has no anal aperture, the excretions being carried -off by a water-vascular system consisting of branching vessels which -end in minute bundles of vibrating cilia, called ciliary flames. -These flames communicate with the exterior through small pores or -flame-cells. Their sense-organs are eyes [pg165] and otocysts. The -latter are sacs containing crystals of carbonate of lime, and their -function is supposed to be that of hearing. - -The flatworms are hermaphroditic, and their propagation is by means -of eggs. They are numerous and very generally distributed, occurring -in fresh and salt water, on land and shore, on the surface and in -the depths of the sea. A vast number also are parasites and infest, -internally or externally, nearly every living creature. The parasitic -forms differ anatomically from the free-living worms. The internal -parasites, living by absorption of the digested food of their hosts, -have no digestive organs; they are also devoid of organs of sense -and of defense. The external parasites, being carried about by their -hosts, are without organs of locomotion. - - -CLASS =TURBELLARIA= - -The turbellarians are the simplest group of bilateral animals and -occupy the lowest place among worms. They owe their name to the fact -that they are covered with cilia, which are constantly in motion and -cause a slight turbulence in the water around them. - - -ORDER =POLYCLADIDA= - -("/Many-branched/") - -The polyclads are found below half-tide mark on the under side of -stones and on seaweeds. Sometimes they are found swimming about -at night. They are leaf-like in form, one inch to two inches in -length, and are very thin and delicate. They adapt themselves to the -inequalities of the surfaces to which they attach themselves, and -often are of the same color, and therefore are so inconspicuous that -they are apt to escape notice. They move with a gliding motion over -surfaces, and often swim when in search of food. - -The intestine is much branched and has no anal aperture. From the -mouth, which is placed in the center of the ventral surface, a -pharynx, or muscular fold, is protruded in some species, which -enables the worm to attach itself to and consume prey of considerable -size. After digestion has taken place, the fecal [pg166] matter -collects in the main intestine and is forcibly ejected by the -pharynx. Numerous eyes are collected in groups on the anterior dorsal -surface, or arranged around the margin of the body. The eggs are laid -in shell-like cases, and cemented together in plate-like masses or in -spirals, and attached to shells or stones. (Plate XLVIII.) - - -GENUS ^Planocera^ - - ^P. nebulosa.^ One half of an inch wide and three quarters of an - inch long, circular or elliptical in shape; very flat and thin; - olive-green on the dorsal surface, with a line of darker color on - the posterior end, and whitish retractile tentacles on the back. - Found creeping on under side of stones in tide-pools. - - -GENUS ^Stylochopsis^ - - ^S. littoralis.^ About one half of an inch long; changeable in - form, from broad oval to elliptical; color pale green, veined with - a lighter shade on the dorsal side, flesh-colored on the ventral - surface; numerous eyes arranged in irregular rows near the margin - and in groups in front of the tentacles, also clusters of eyes on - the tentacles. Found under stones between tide-marks. - - -GENUS ^Leptoplana^ - - ^L. folium.^ Body flat; margin thin and undulated; shape leaf-like, - but changeable; about one inch long and one half of an inch wide; - color pale yellow, veined with a deeper shade; eyes in four groups - near the anterior end. - - -ORDER =TRICLADIDA= - -("/Three-branched/") - -The triclads are divided into three groups: those of the fresh-water -ponds and streams, those of the land and sea, known as planarians, -and those of the sea. The planarians are the most interesting worms -in the order. The triclads differ from the polyclads in being -elongate in form and in having the intestine in three branches -instead of in many. The mouth is midway in the length of the body, -on the ventral side, and from it protrudes a pharynx, which is -cylindrical or bell-shaped, and is capable of great dilatation. With -the pharynx the worm, which is wholly carnivorous, envelops other -worms, crustaceans, or any animal food. Several species are found on -the under side of stones in tide-pools. - -[Illustration: PLATE XLVIII. Polyclad worm. Worm-tubes of Diopatra.] - - - -GENUS ^Planaria^ - - ^P. grisea.^ Oval or elliptical in form; anterior end truncate; - posterior end rounded; color yellow or gray, with a light stripe; - two black eyes surrounded with white; length one half to three - quarters of an inch; width about one eighth of an inch. Found under - stones between tide-marks. - - -GENUS ^Procerodes^ - - ^P. frequens.^ One eighth of an inch long; brown or black above, - gray below; has two kidney-shaped eyes; active and abundant. Found - under stones near high-water mark. - - -GENUS ^Bdelloura^ - - ^B. rustica.^ Body milk-white, smooth, thin. Found on /Ulva - latissima/ (sea-lettuce). - - ^B. candida.^ Parasitic on the gills of the horseshoe-crab. - - -GENUS ^Fovia^ - - ^F. Warrenii.^ Bright red, narrow, oblong. Found on eel-grass. - - -ORDER =RHABDOC[OE]LIDA= - -Minute, active worms found among the red seaweeds. They are brown in -color, and are marked by one or more transverse white bars. - - -CLASS =NEMERTINEA= - -The nemerteans are long, narrow, flat, smooth worms, and vary from -one half of an inch to many feet in length. They are exceedingly -contractile, and when alarmed can shrink to less than half their -normal length. They are very generally distributed, and are to be -found between tide-marks, in loose coils like a string, under stones -on sandy and muddy shores. The very long species, like /Lineus -marinus/, are solitary, but other smaller species are gregarious, -many worms being coiled together in tangled masses. Some species are -to be found in empty shells, and others live among the seaweeds. They -are very slimy, the epidermis secreting an abundance of mucus, and -they can often be tracked by the trail of slime they leave behind -them. This mucus sometimes hardens, forming for some species a -tubular [pg168] covering; others remain naked. All are covered with -vibrating cilia, which is a universal feature of flatworms. In color -they may be white, yellow, green, red, purple, etc., and sometimes -they are banded or striped with a contrasting color. The ventral is -usually lighter than the dorsal surface. - -The principal characteristic of the nemertean worms is a long -thread-like organ, known as the /proboscis/. This lies in a sheath -along the center of the dorsal surface, and is quickly thrown out -to a great length, and as quickly completely withdrawn within the -body. The proboscis is slender, hollow, muscular, and full of nerves. -It reaches the outside through a pore at the anterior end of the -body, and has no connection with the alimentary system. It is used -as a feeler and as a weapon. Some species have a sharp spine at the -end of the proboscis, others have stinging-cells. The proboscis is -sometimes so forcibly ejected that it breaks off, in which case it -retains its vitality for some time, and seems as if it were itself a -worm. A new proboscis is quickly grown by the worm to take the place -of a lost one. The head is a little broader than the body, and has -eyes arranged in one or several pairs on each side. The mouth is on -the ventral surface, near the anterior end, has thick lips, and is -very dilatable. Through the mouth the animal ejects a part of the -esophagus and envelops its prey, which is often of considerable size. -Chaetopod worms they often swallow whole; the soft parts, after being -digested, are carried off through the regular passages, ending in the -ciliary flames (page 164), while the indigestible parts are ejected -at the anus. Often the spines and bristles find their way out by -perforating the intestine and the body-wall, without apparently doing -the worm any injury. The perforated parts quickly heal. - -These worms have the strange power of regenerating lost parts; -mutilated portions are soon repaired. The anterior end, when severed -from the rest of the body, grows again into a complete individual, -while the posterior end continues to perform part of its functions -and retains its vitality for a considerable time before dying. One -species, /Lineus sanguineus/, is capable, after being broken in -pieces, of regenerating each section into a perfect worm. [pg169] - -The nemerteans are carnivorous, voracious, and often cannibalistic. -They will live for some time in confinement, losing, however, their -bright color, and the smaller worms will gradually disappear, as they -are devoured by the larger ones. The mode of locomotion varies with -the order. Some species attach their long proboscis to a distant -object, then drag the body to it; some glide rapidly along by means -of the muscles of the body and the cilia which cover it; others swim. -The swimming forms have thin edges which have a wave-like motion, -and this, together with a lateral movement of the tail, propels them -through the water. In some species the worm develops directly from -the egg; others pass through a larval stage before reaching maturity. - - -GENUS ^Tetrastemma^ - - ^T. arenicola.^ Dark flesh-color or purplish; slender, cylindrical, - four to five inches long when extended; head changeable in form and - partly distinct from body because of slight constriction at the - neck. It lives in sand at low-water mark. - - -GENUS ^Nemertes^ - - ^N. socialis.^ Individuals very slender, five to six inches long - when extended; color brown or black, a little lighter underneath; - three or four eyes in lines on each side the head. It is abundant - under stones on rocky shores, many coiled together, forming large - masses. - - ^N. viridis.^ Color olive-green or brown, crossed by faint pale - lines; body changeable in form; when extended, six to eight inches - long, one eighth of an inch or less in breadth; row of dark eyes on - each side of flat head. Common under stones between tide-marks on - northern rocky shores. - - -GENUS ^Meckelia^ - - ^M. ingens.^ One of the largest nemertean worms; found on sandy and - muddy shores near low-water mark. The young, from several inches to - a foot long, are common. When full-grown some attain the length of - twelve or thirteen feet, and are an inch in breadth and quite flat - when extended, but can contract to two or three feet in length, - and are then nearly cylindrical. This worm, although so soft, - penetrates the sand with great rapidity. Its head changes shape - constantly and assists the proboscis when burrowing. It is also - able to swim. Its color is yellowish or flesh-color, with whitish - edges and a central band. - - ^M. rosea.^ The largest specimens are six to eight inches long and - one quarter of an inch broad; lives in burrows on sandy beaches; - color red or pink; often covered with sand, which adheres to the - mucus which the worm secretes. [pg170] - - -GENUS ^Cerebratulus^ - - ^C. angulatus.^ Olive-green, with light dorsal stripe. - - -GENUS ^Cosmocephala^ - - ^C. ochracea.^ Two to three inches long when extended; gray or - yellowish-white, and mottled by the internal organs showing through - the translucent body; line of lighter color down the back; anterior - end often orange-colored. It is common near low-water mark under - stones and in the dead tubes of /Serpula/. - - -GENUS ^Polina^ - - ^P. glutinosa.^ One to two inches long; color orange or light - yellow, with a faint line of deeper color down the center of the - dorsal surface; very slimy; eyes numerous, in oblique lines on the - head. Found in tide-pools on algae. - - -PHYLUM =NEMATHELMINTHES= - - -ROUNDWORMS - -The worms of this phylum have the general name of roundworms, which -distinguishes them from the flatworms of the preceding division and -from the segmented worms of the /Annulata/. The body is elongated, -cylindrical, smooth, and pointed at both ends. With few exceptions, -they are parasitic. - -A few of the nematode species are free, living under stones and among -seaweeds at about low-water mark. - - -CLASS =NEMATODA= - - -GENUS ^Pontonema^ - - ^P. marinum.^ Slender, white, smooth, active, cylindrical; - constantly coiling and uncoiling itself. - - -PHYLUM =ANNULATA= - - -SEGMENTED WORMS - -The name of this phylum expresses the principal characteristic of -the group of worms which have elongated bodies composed of series -of short parts, or ring-like divisions. Each one of these segments -contains a separate and similar set of internal organs. [pg171] - -The annelids are divided into four classes, one of which, the -/Gephyrea/, has not the characteristics which distinguish the group. -The classes are easily recognized by conspicuous features. Some have -bristles; others have scales; others have tentacles around the head -and inclose themselves in tubes. Many are highly colored, and all -are of great interest to the naturalist from the diversity of their -habits, form, and structure, and from the analogies they bear to -other and higher types of animals. - -The annelids are the highest type of worms, their organs having -attained more special functions. The sense-organs of eye and ear -are more developed, and the nervous system has distinct centers, -or ganglia, the first and largest ganglion being a part of the -head. They are found in abundance everywhere. Some species grow to -the length of one foot or two feet. Some are carnivorous, others -vegetarian, and many are mud-eaters, swallowing sand and mud for the -sake of the organisms they contain. They themselves are food for -fishes, which devour them in vast quantities, rooting them out of -their burrows or capturing them at night, at which time they swim -about. - - -CLASS =CHAETOPODA= - -("/Bristle-footed/") - -[Illustration: A magnified parapodium of /Nereis dumerilii/: /dors. -cirr./, dorsal cirrus; /vent. cirr./, ventral cirrus; /s/, setae.] - - -The bristle-worms. This class of worms has bunches of bristles on -both sides of each segment of the body, which serve as organs of -locomotion, or bristle-feet. The bristles emanate from outgrowths -of the body known as /parapodia/, which are practically limbs. The -parapodia are sometimes divided into distinct lobes or branches. The -bristles are of various shapes and often of brilliant color. They -are usually horny, sometimes simple, sometimes divided into joints, -and vary in shape in different genera. The parapodia have, besides -the bristles, a second set of [pg172] hair-like appendages, called -/cirri/. These are sense-organs and also have a respiratory function. -The cirri too vary in shape in different genera. Generally they are -hair-like, but sometimes conical; again they are broadened into -scales, as in the /Aphroditidae/. - -The body-cavity in chaetopod worms is divided into a series of -chambers or segments. These divisions seem on the exterior like -constrictions, and give the body the appearance of a series of rings. -The internal organs are repeated in each segment, so that each of -the latter contains a portion of the alimentary canal, a pair of -/nephridia/, a pair of nerve-ganglia, and blood-vessels which connect -the main blood-vessels running along the dorsal and ventral surfaces. -The alimentary canal runs through the body, but is constricted at -each joint. The nephridia are curved tubes, which are excretory -organs, opening to the outside and carrying off the waste products -which have passed into the fluid of the body-cavity. - -The chaetopod worms have a well-developed nervous system, beginning -with a two-lobed ganglion forming a brain and head, then extending -through the worm in a double ventral chain and series of ganglia. -They have also a blood-vascular system. The blood is either colored -or colorless. Sometimes it is a bright red or green, and is often -visible through the body-wall. The circulation is effected, not -by means of a heart, but by wave-like (peristaltic) contractions -of the dorsal blood-vessel. The body is cylindrical, but in many -cases is somewhat flattened. There are two layers of muscles, one -of which encircles the body, while the other extends parallel with -its length. Respiration is effected by /gills/, which may be simple, -hair-like appendages to the parapodia, or branched, or comb-like -in form. Sometimes they are confined to the middle segments, as -in /Arenicola/; sometimes to the segments near the head, as in -/Tubicola/; or they may be extended over the whole dorsal surface. - - -SUBCLASS =POLYCHAETA= - -("/Many-bristled/") - -The polychaete worms have one or two well-developed parapodia, or -limbs, on each side of every segment of the body, and on each -[pg173] parapodium is a bunch of bristles, or /chaetae/. There are -hundreds of species of this class of worms, the species being based -on the shape and the lobes of the parapodia, the relative length of -the cirri, the form and arrangement of the chaetae, and so on. They -are abundant on the shore everywhere, but abound where rocks and -stones afford them some shelter. Many burrow in the sand and mud. -In doing this the worm eats his way into the hole, swallowing the -mud and sand. He assimilates the organic or vegetable matter the -mud contains, and ejects the rest in cylindrical coils, known as -castings, which lie in heaps at the mouth of the burrow. By these -castings they may be traced. Others secrete tubes. - -The polychaete worms are divided into /Errantia/, which are wandering, -free-swimming forms, and /Sedentaria/ or /Tubicola/, which live in -tubes permanently. These distinctions are not strictly correct, since -some species of errant polychaetes form tubes (/Eunicidae/), and some -/Sedentaria/ form no tubes. - -Many polychaetes are beautifully colored, some in vivid reds and -greens, with various markings; some are iridescent; some are -phosphorescent. - - -ORDER =ERRANTIA= - -Carnivorous, free /Polychaeta/, with protrusible pharynx armed with a -horny jaw. "They are active, fierce beasts of prey." - - -FAMILY ~SYLLIDAE~ - -This family is the highest in organization of the worms. They are -small, the majority being less than an inch in length, and many are -minute. They are often highly colored. Many have long cirri on the -feet; some have alternation of generation. They are common everywhere -along the coast, but are not seen unless searched for. Sponges -sometimes are alive with them. They are interesting subjects for -microscopic study. - - -FAMILY ~APHRODITIDAE~ - -The scale-bearing annelids. This family of worms is distinguished -from all others by having scales on the back. The scales, called -/elytra/, are flattened dorsal cirri carried on the upper parapodia, -[pg174] and generally on alternate segments and in a double row down -the back. The elytra are the breathing-organs, and, although of a -horny texture, are richly supplied with nerves. The worms are short -and have a large protrusible pharynx armed with a double pair of -horny jaws. - - -GENUS ^Polynoe^ - -The species of /Polynoe/ are determined by the number of scales they -bear. They have a flattened short body with nearly parallel sides. -The bristles are of a bright golden color. The proboscis is large and -has four powerful jaws at the end and a circle of papillae at the top. -They are sluggish in movement and are found under stones and in the -crevices of rocks. When disturbed they roll themselves into a ball. - - ^P. squamata.^ Twelve pairs of rough scales; color sandy-brown, - speckled; one inch to one and a half inches long; the broad, oval - scales overlap and entirely cover the body and head. Some /Polynoe/ - when disturbed throw off every scale. Very common north of Cape Cod. - - ^P. sublevis.^ Twelve pairs of smooth scales; usually grayish-brown - in color, speckled with dark spots; iridescent; last pair of scales - more slender than the others; length one and a quarter inches, - breadth about one quarter of an inch. - -[Illustration: /Polynoe squamata./] - - -GENUS ^Harmothoe^ - - ^H. imbricata.^ Sixteen pairs of smooth scales; variable in color; - usually gray, speckled, or striped. - - -GENUS ^Aphrodite^ - - ^A. aculeata.^ This polychaete, sometimes called the sea-mouse, is - one of the most beautiful of worms. It is brightly iridescent in - color, from its setae, which form a fur-like coating over the dorsal - surface. It has fifteen pairs of scales, but they are hidden by - the numerous setae. These bristles cover its sides and back. Some - are coarse and nearly an inch long, with sharp points, and are - barbed near the ends. They curve over the back like the quills of a - porcupine. The body is three to six inches long. It is broadest in - the middle and tapers to a point. They live in mud below tide-mark, - and may be found washed upon the beach after storms. [pg175] - - -FAMILY ~PHYLLODOCIDAE~ - -[Illustration: /Aphrodite aculeata/, natural size: /c/, neuropodial -chaetae; /p/, palps; 1, iridescent bristles; 2, stiff chaetae; 3, felting -bristles of notopodium.] - -These animals are commonly known as "paddle-worms," on account of -having leaf-like cirri, which they use in locomotion. The head is -long and bears four pairs of short and four pairs of long tentacles. -The body is long and depressed, sometimes two feet in length, usually -eight to twelve inches long. The general color is bright green and -iridescent. Found in tide-pools. Specimens are often found by digging -in sandy mud, or they may be obtained by placing old shells and other -material in a dish of sea-water. When the water becomes a little -stale, the worms of this and other families make their way to the -sides of the dish, where they secrete a colorless slime which holds -mud or any light matter that it may come in contact with. In this -condition, when lifted or disturbed, they crawl rapidly out of the -slime, and show to good advantage their elongate body, which is often -beautifully colored. - - -GENUS ^Phyllodoce^ - -[Illustration: /Phyllodoce paretii./] - - ^P. gracilis.^ Three inches or more long and one sixteenth of - an inch wide; large proboscis, with twelve longitudinal rows of - prominent [pg176] projections on the swollen base, its terminal - end smooth, with a circle of round projections at the orifice; - color green, with a row of dark spots down the center of the dorsal - surface and a fainter line of spots on each side at the base of the - parapodia. Found on the New England coast. - - -FAMILY ~NEREIDAE~ - - -GENUS ^Nereis^ - -[Illustration: Head of /Nereis pelagica/.] - -Among the most common of the polychaete worms is the genus ^Nereis^, -various species of which are found in all parts of the world. They -are abundant under stones, among seaweeds, and living in burrows -between tide-marks. They are active, fierce, and voracious. Some -attain a length of eighteen or more inches. They are commonly known -as "clam-worms," and are used by fishermen for bait. /Nereis/ has a -distinct head, consisting of two parts. One, the /prostomium/, bears -on its upper side four eyes and a pair of short, conical tentacles, -and on the lateral sides a second pair of processes called /palps/. -The palps are more conspicuous than the tentacles, and consist of two -parts, a large base and a small terminal point, the latter capable -of being withdrawn. The palps are sense-organs and perhaps test the -food. The second part of the head, or /peristomium/, bears on the -sides four pairs of long tentacles which are used as feelers. The -mouth is on the ventral side, and through it /Nereis/ throws out -its pharynx, which contains a horny, notched jaw. It seizes its -prey with this jaw, which, with the pharynx, is then withdrawn and -tears the food apart, acting like a gizzard. The body of /Nereis/ -is rounded above and nearly flat below. Each of the segments has a -pair of parapodia, bearing a bundle of bristles and cirri. The last -segment of the body is elongated, cylindrical, and without parapodia, -but has on the end a pair of long cirri, which give the appearance -of a divided tail. Each segment of the body, except the head- and -tail-segments, contains a pair of excretory tubes (/nephridia/), -ganglia of nerves, and a portion of the intestine and of the vascular -system. There are circular muscles by which the worm can diminish its -diameter, longitudinal [pg177] muscles in four bands, and muscles to -move the parapodia. Breathing is carried on over the whole surface -of the body, and especially in parts of the lobes of the parapodia -called gills. Its sense-organs are eyes, palps, tentacles, and cirri. - - ^N. virens.^ This species is found from New York northward in - muddy and shelly sand, and under rocks between tide-marks, living - in burrows, which it lines with a mucous secretion. It is very - active, and voracious, feeding on other worms, /Crustacea/, etc., - which it captures with its horny, protruded jaw. At night it - leaves its burrow and swims freely about like an eel, frequently - falling a prey to fishes. In color it is dull bluish-green, with - some iridescence. The gills, which are leaf-like appendages on the - parapodia, are green on the anterior end of the body and become - bright red farther back. This species, and /N. branti/ of Alaska, - are the giants of polychaete worms, often measuring eighteen inches - or more in length. - - [Illustration: /Nereis pelagica./ 1, male; 2, female.] - - ^N. pelagica.^ Found in abundance on the New England shore and - northern coasts under stones and on shelly bottoms. The female is - four to five inches long, while the male is only two inches in - length. In this species the body is widest in the middle, while in - other species it is widest at the anterior end. The palps are long, - and the second head-piece (peristomium) is twice as long as the - next segment. The color is reddish-brown and iridescent. - - [Illustration: /Nereis limbata./ Male, anterior part of body, head - and extended proboscis.] - - ^N. limbata.^ Five to six inches long; jaws light yellow, sharp, - and slender; parapodia and bristles smaller on the anterior than on - the posterior end; color dark brown, with light lines on the sides - and appendages, pale red on the posterior end; dorsal blood-vessel - apparent, and the heart-like pulsations can be distinctly seen. - The male worm is red in the middle section. Found along the middle - Atlantic coast on sandy shores. - - -FAMILY ~NEPHTHYDIDAE~ - -In this family the worms have a long, thick, flattish body, a section -of which has a quadrangular form. The lobes of the parapodia are -widely separated and fringed [pg178] with membrane, appearing like -double parapodia. The pharynx is very large and projected as in -/Nereis/. - - -GENUS ^Nephthys^ - - ^N. ingens.^ Sometimes six inches long and one quarter of an inch - broad; usually smaller; color whitish, with red blood-vessel - showing on dorsal side; appendages dark blown; moves actively - and burrows quickly into the mud; when captured often breaks off - a portion of the posterior end, which it is able to reproduce; - proboscis large; branchiae between the dorsal and ventral parapodia. - Found burrowing in all kinds of mud on the New England coast. - -[Illustration: /Nephthys ingens./ Anterior part of body and extended -proboscis; ventral view. Enlarged.] - - ^N. picta.^ More slender than /N. ingens/; color whitish, mottled - with brown on the dorsal anterior end; often a dark line down the - back; head square in front and triangular in the back. Found in - sandy mud at low-water mark. - - -FAMILY ~EUNICIDAE~ - -These are beautiful worms, having a reddish-brown iridescent body, -with bright-red branching gills, which look like feathers, along the -back. They form parchment-like tubes. - - -GENUS ^Marphysa^ - - ^M. sanguinea.^ Length six inches or more; color bronze or - brownish-red and iridescent; has bright-red branched gills and six - caudal cirri of different lengths; body flattened, except at the - anterior end, where it becomes narrow and cylindrical; has powerful - jaws. It is found under stones and in clefts of rocks at low-water - mark, or more commonly in parchment-like tubes on shelly beaches, - from Cape Cod to New Jersey. - - -GENUS ^Diopatra^ - - ^D. cuprea.^ This is one of the largest and most beautiful - annelids. It is found from Cape Cod to South Carolina at low-water - mark, in sandy mud-flats, living in long tubes which project above - the surface two or three inches and are hung with seaweeds and bits - of foreign matter. /Diopatra/ is twelve inches or more in length - and one half of an inch in breadth. In color it is reddish-brown, - specked with gray, and has a brilliant whitish or opal-like - iridescence. The appendages are yellowish-brown, specked with - green. The body is flattened. From the fifth segment long, dull - to bright red, much-branched gills, resembling plumes, [pg179] - extend nearly to the end of the worm. On the ventral side of the - parapodia are whitish tubercles with a dark spot in the middle. - These papillae secrete the long, broad tube in which the worm lives. - The worm is difficult to capture, for when pursued it retreats - quickly into its tube, which is so large that it can easily turn - around within it. (Plate XLVIII.) - -[Illustration: /Diopatra cuprea./ Head and anterior part of body, -showing part of the branchiae; side view.] - - -GENUS ^Arabella^ - - ^A. opalina.^ Body cylindrical, twelve to eighteen inches long, - one quarter of an inch wide in the middle, and tapers to the ends, - which are comparatively small; lateral appendages short; color - bronze, with brilliant, opal-like iridescence; head small, conical, - but blunt and without tentacles; four eyes in transverse row at the - base of the head; segments well marked; coils into spirals when - outside of its burrow. Found in compact sandy mud at low-water mark - on the New England coast. - - -GENUS ^Lumbriconereis^ - - ^L. tenuis.^ Twelve inches or more long, and slender, like a fine - cord; bright red and somewhat iridescent; very fragile. Abundant - in sandy mud on the northern New England coast, and found from New - Jersey northward. - - -FAMILY ~GLYCERIDAE~ - -These worms are long and smooth, with numerous segments. They taper -at both ends. The head is small, conical, sharply pointed, and has -four very small tentacles. The proboscis, or [pg180] pharynx, when -protruded, is very large and long, and appears too large for the -worm. The proboscis has four hook-like jaws. These worms burrow -rapidly and disappear almost instantly into the mud or sand. - -[Illustration: /Glycera meckelii/, with pharynx everted.] - - -GENUS ^Glycera^ - - ^G. americana.^ Color red or purple; has branched gills on upper - side of parapodia. Found from South Carolina to Cape Cod on sandy - and muddy shores and flats near low-water mark. - - ^G. dibranchiata.^ Has a simple gill on both sides of the - parapodia; about eight inches long and one quarter of an inch wide - in the middle; proboscis one inch long and wider than the body on - the upper end. Abundant from New Jersey to Cape Cod. - - -ORDER =SEDENTARIA= - -THE TUBICOLOUS WORMS - -Many of this order construct tubes in which they live permanently. -Some species of both /Sedentaria/ and /Errantia/ have habits -pertaining to the other. These worms are without a protrusible -pharynx and without jaws. The body is usually divided into two or -three sections by segments and appendages of different forms. They -have hair-setae on a limited number of segments only, varying with the -species; the remaining segments have /uncini/, or hooked comb-like -rows of setae, which are very small, but often crowded in bunches. -Uncini exist also on segments having hair-setae. Parapodia are often -lacking on the posterior parts and are usually without cirri. The -gills are usually confined to the anterior end and are sometimes -represented by tentacles around the head. The different species have -characteristic tubes, formed by mucus secreted by epidermal glands. -Sometimes the mucus hardens, making a parchment-like tube; again it -cements together grains of sand, or bits of shell, seaweeds, etc. -Some species secrete [pg181] calcareous tubes; these are often found -on rocks, in coral, and in the shells of mollusks. The anterior end -of the body is more highly developed than the posterior end. - - -FAMILY ~SPIONIDAE~ - - -GENUS ^Nerine^ - - ^N. agilis.^ Two to three inches long; slender; somewhat flattened - at the anterior end; head conical and sharp; the two tentacles - about one half of an inch long; four eyes; color reddish-brown, - light green on the sides; gills red; tentacles greenish-white. It - burrows with extreme rapidity and lives on exposed beaches near - low-water mark. - - ^N. coniocephala.^ Two and a half inches long, one sixteenth of an - inch in diameter; head conical; body flattened on the dorsal side, - round on the ventral side; has two long tentacles turned backward - and a membrane on the gills of the anterior segments; gills red; - bristles long and numerous. - - -FAMILY ~CIRRATULIDAE~ - -Worms of this family have a cylindrical body, more or less attenuated -at each end; segments similar throughout; many segments with long, -filamentous cirri which act as gills; and a conical head. They live -in burrows. - - -GENUS ^Cirratulus^ - -[Illustration: /Cirratulus grandis./] - - ^C. grandis.^ Four to six inches long; head acute; segments - numerous, short, and distinct; color dull yellow, or orange, - to brown, often iridescent beneath; ventral surface somewhat - flattened. Numerous long, filamentous, red to orange-colored cirri - extend nearly the whole length of the body and act as gills. It is - common in sand and gravel at low-water mark from Cape Cod to New - Jersey. [pg182] - - -FAMILY ~TEREBELLIDAE~ - -The body is cylindrical and largest on the anterior end; there are -one to three pairs of more or less branched gills on the anterior -end, and the ventral surface of the anterior segments is thickened by -glands which secrete mucus for tube-building. These gland-spaces are -called /shields/. - - -GENUS ^Thelepsus^ - - ^T. cincinnatus.^ Two to four inches long; pale red; marked like - lacework on the back; gills have numerous unbranched filaments - arising separately in two transverse rows; tubes thin, transparent, - flexible, and hung with foreign substances; attached along the - whole length. - - -GENUS ^Amphitrite^ - -[Illustration: /Amphitrite ornata./] - - ^A. ornata.^ Twelve to fifteen inches long; flesh-color, reddish, - or brown; three pairs of red plume-like gills and numerous - flesh-colored tentacles around the anterior end; tentacles - constantly in motion and sometimes extended eight or ten inches; - tubes a quarter of an inch or more in diameter, and firm, being - composed of sand and mud. It is found under stones in mud, gravel, - and sand at low-water mark from Cape Cod to New Jersey, often - associated with /Cirratulus grandis/. - - - GENERA ^Polycirrus^, ^Chaetobranchus^ - - [Illustration: /Polycirrus eximius./] - - ^P. eximius^, ^C. sanguineus^. These are two species of bright-red, - fragile worms, found under stones, in mud. They do not form - tubes. The first is a small worm, the second twelve to fifteen - inches long. Both have long, crowded tentacles extending in - every direction and distended as the blood flows into them. /C. - sanguineus/ has [pg183] tentacles sixteen inches in extent, and - branched gills on short pedicels on the back. They are common in - mud at low-water mark from Cape Cod to New Jersey. - - -FAMILY ~AMPHICTENIDAE~ - - -GENUS ^Cistenides^ - -[Illustration: /Cistenides Gouldii./ ] - - ^C. Gouldii^ constructs conical free tubes of grains of sand in - a single layer; body short and a little curved; head obliquely - flattened; two broad groups of golden bristles turned upward on - each side of the anterior end; one to two inches long; color - light red or flesh-color, mottled with red or blue. This is a - common worm, and its horn-shaped tubes are so plentiful as to - attract attention on sandy shores. They will repay examination - with a glass, so beautifully are they built. The worm has - bunches of golden bristles arranged in two rows close to the - flattened anterior end, which make a kind of operculum to the - tube. This feature makes the species easy to identify. The worm - is transparent; the internal organs showing through give it the - various bright colors. It is found on sandy and muddy shores from - New Jersey northward. - - -FAMILY ~MALDANIDAE~ - -The tubes of these animals are formed of sand, a short portion -projecting, and are very abundant in certain places. There is a horny -plate on the upper surface of the head, and the skin on the sides of -the head is raised in folds. There is a funnel-like process at the -posterior extremity; gills are lacking. Some of the segments in the -middle of the body are longer than the rest. - - -GENUS ^Clymenella^ - -[Illustration: /Clymenella torquata./ /a/, head and extended -proboscis, front view; /b/, posterior end; /c/, entire animal, side -view, natural size.] - - ^C. torquata.^ Body long, composed of twenty-two segments; the - fifth segment has a collar-like fold; the caudal extremity is - funnel-shaped and edged with papillae; both [pg184] the first and - the last three segments are bare, the rest have short bristles - above and hooks below; head has a prominent convex plate with a - raised border; worm pale red, with bright-red bands around the - segments, sometimes brownish. It constructs nearly straight tubes - of pure sand close to low-water mark in sheltered coves, and ranges - from New Jersey northward. - - -GENUS ^Maldane^ - - ^M. elongata.^ Six to eight inches long, one eighth to one quarter - of an inch in diameter; body cylindrical, cut obliquely at both - ends; head bordered by a slight fold; color brown, with red blood - showing through. Found in sandy mud at low-water mark, in firm, - deep tubes of fine mud, on the New England coast. - - -FAMILY ~ARENICOLIDAE~ - - -GENUS ^Arenicola^ - - ^A. marina.^ Five to ten inches long; brownish-green; body - cylindrical, thickest on the anterior end; anterior and posterior - ends without chaetae; twelve to thirteen pairs of branched red gills - on the central segments. It makes burrows eighteen to twenty-four - inches deep on sandy southern shores, and can be traced by castings - at the mouth of the burrow. Commonly known as "lugworm," and used - by fishermen for bait. - - -FAMILY ~SABELLIDAE~ - -In this family the gills arise from two semicircular bases forming -the crown; the second lobe of the anterior extremity is reversed like -a collar; the gill-filaments have secondary processes, and the tubes -are flexible, composed of cemented mud or sand. Found under stones, -the tube passing around the stone and opening upward. - - -GENUS ^Sabella^ - - ^S. microphthalma.^ Length of tube one and a quarter inches, - diameter one eighth of an inch; body olive-green, specked with - white; wreath of tentacles half as long as the body; tentacles pale - yellowish or flesh-colored, with transverse lines of darker color. - It is found on the southern New England coast. - - -FAMILY ~SERPULIDAE~ - -This family forms white calcareous tubes. One of the dorsal -gill-filaments is flattened, forming an operculum, or cover, with -[pg185] which the tube is closed when the worm has withdrawn itself -inside. The tubes are commonly found attached to shells and rocks, -usually solitary, but sometimes in clusters, crossing and recrossing -each other on the surface of the shell or rock. Plume-like gills -are attached to the anterior end of the body. The color differs -in different species. These worms may easily be mistaken for the -mollusks /Vermetus/, which live in similar tubes of larger size, -growing in masses. - - -GENUS ^Serpula^ - - ^S. dianthus.^ Tubes often three inches long and one eighth of - an inch wide, the fixed end coiled and contorted, free end with - circular opening; tubes often show circular ridges, marking periods - of growth; operculum funnel-shaped, the exterior striated and the - edge bordered with short processes; wreath of gills nearly circular - and divided into two symmetrical parts; color variable. It is found - in tide-pools, also on the under side of rocks at low-water mark, - either solitary or congregated in masses, and ranges from Cape Cod - to New Jersey. - - -GENUS ^Spirorbis^ - - ^S. borealis.^ A minute calcareous tube, in a close, flat coil - attached on one side; easily mistaken for a minute gasteropod - shell; worm has an operculum and wreath of gills. Found on the - fronds of seaweeds, on shells, etc. - - - - -CLASS =GEPHYREA= - - -This class of animals, once placed near the holothurians, belongs -with the annelid worms on account of their mode of development, -their structure being entirely dissimilar. They are without segments -and without parapodia. The body-cavity is filled with fluid and is -traversed by connective tissue and fine muscular fibers. They are -subcylindrical animals which can retract the anterior end of the -body. The mouth is surrounded by tentacles, or by tentacular folds, -and is at the base of the proboscis. They live in fissures of rocks, -in sand, mud, rock, or coral, and in deep gasteropod shells. Their -distribution is general. - - -ORDER =SIPUNCULOIDEA= - - -GENUS ^Sipunculus^ - - ^S. nudus.^ The body is cylindrical, a foot or more in length - when extended. It is divided into two portions. The anterior end, - to the [pg186] extent of one sixth of the entire length of the - worm, is capable of being withdrawn into the remainder of the body. - This portion is called the /introvert/. The introvert is retracted - by means of special muscles forming a sheath around the gullet - and connected at the other end to the body-wall about half-way - down the body. It is narrower than the rest of the body and is - covered more or less closely with small horny papillae which turn - backward and overlap like scales. The rest of the body is divided - into longitudinal furrows and circular markings, giving it the - appearance of being divided into squares. These markings correspond - to muscles which lie beneath. The introvert, when retracted, leaves - at the opening a lobed and plaited fold of the integument, giving - the appearance of tentacles. When the introvert is expanded there - is a fringe-like funnel around the mouth. The body is covered with - a horny cuticle and has an iridescent luster. The animal lives - buried in the sand and feeds upon sand, deriving its nourishment - from the organisms contained therein. The sipunculoids pass so much - sand and mud through their bodies that they are said to modify the - mineral substances on the bottom of the sea, as earthworms do the - soil of the land. - - -GENUS ^Phascolosoma^ - - ^P. Gouldii.^ Body cylindrical, a foot or more in length, a - quarter or half of an inch in diameter when expanded; but the - body constantly changes in size and shape as it is contracted or - expanded; surface of body parchment-like in texture and marked off - in small squares; color dull white to light brown. It is found on - the New England coast in sand and gravel at low-water mark. - - - - -IV - -MOLLUSCOIDA - - -TABLE SHOWING THE CLASSIFICATION OF THE MOLLUSCOIDA DESCRIBED IN THIS -CHAPTER - - Class =POLYZOA= - - Subclass =Ectoprocta= (/Excretory opening outside lophophore; - mouth in center of circle of tentacles; tentacles retractile/) - - Order =GYMNOLAEMATA= (/Circular lophophore/) - - Suborder ~CYCLOSTOMATA~ (/Tubular calcareous zo[oe]cia, - with circular apertures devoid of closing apparatus/) - - Set ARTICULATA (/Erect branches divided at intervals by - chitinous joints/) - - Genera Species - - ^Crisia^ ^C. eburnea^ - - Set INARTICULATA (/Erect or adherent zoarium; unjointed/) - - ^Tubulipora^ ^T. flabellaris^ - ^Diastopora^ ^D. patina^ - - Suborder ~CHEILOSTOMATA~ (/Calcareous or chitinous - zo[oe]cia, usually with opercula; avicularia, vibracula, - and ovicells often present/) - - Set CELLULARINA (/Flexible erect forms/) - - - ^AEtea^ ^AE. anguinea^ - ^Eucratea^ ^E. chelata^ - ^Cellularia^ ^C. ternata^ - ^Caberea^ ^C. Ellisii^ - ^Bugula^ ^B. turrita^ - ^B. Murrayana^ - ^B. flabellata^ - - Set FLUSTRINA (/Cells quadrate; front wall of zo[oe]cium - membranous or depressed, and has ridge-like margin/) - - ^Flustra^ ^F. membranacea^ - ^Membranipora^ ^M. pilosa^ - ^M. lineata^ - ^M. tenuis^ - - Set ESCHARINA (/Zo[oe]cium wholly calcified/) - - ^Escharella^ ^E. variabilis^ - ^Mollia^ ^M. hyalina^ - ^Cellepora^ ^C. scabra^ - ^C. ramulosa^ - ^C. pumicosa^ - - Suborder ~CTENOSTOMATA~ (/Horny or gelatinous zo[oe]cia, - having tooth-like processes which close the apertures when - the tentacles are retracted/) - - ^Alcyonidium^ ^A. ramosum^ - ^A. hirsutum^ - ^A. hispidum^ - ^A. parasiticum^ - ^Vesicularia^ ^V. dichotoma^ - ^V. custata^ - - Subclass =Entoprocta= (/Excretory opening within lophophore; - mouth near margin of area, which is surrounded by tentacles; - tentacles roll up instead of being retracted/) - - ^Pedicellina^ ^P. americana^ - - -[pg190] - - -TERMS USED IN DESCRIBING POLYZOA - -^Avicula'ria^: Specifically modified zo[oe]cia, resembling a bird's -head, found only in the /Cheilostomata/. - -^Brown bodies^: Brown pigment-masses contained in the zo[oe]cia and -derived from the breaking down of the polypides. - -^Lo'phophore^: The disk bearing the mouth and circlet of ciliated -tentacles. - -^Orifice^: The open end of the zo[oe]cium. - -^Ovicell^: The receptacle in which the eggs develop. - -^Pe'ristome^: The ridge around the orifice of cell. - -^Po'lypide^: The parts of the animal within the zo[oe]cium. - -^Vibra'cula^: A lashing filament, or specifically modified zo[oe]cia, -found only in the /Cheilostomata/. - -^Zoa'rium^: The whole colony. - -^Zo[oe]'cium^: The body-wall of a single individual. [pg191] - - - - -POLYZOA - - -Among the numerous objects to be found on the beach at low tide -are the /Polyzoa/, of which there are said to be seventeen hundred -named species of the marine forms. These little animals, although -so plentiful, are inconspicuous, and it may be said that their very -existence is not known to those who are not professed naturalists; -yet they are easy to see, incrusting with a delicate calcareous -lacework the surface of stones and shells and seaweeds in the -tide-pools, and hanging from the rocks like branches of delicate -seaweeds. There is hardly a frond of even the fine red algae on which -cannot be found the little tube holding shelly saucers, or the -creeping stems or branches of polyzoans. Any one of these little -masses, when examined with a pocket-glass, will surprise one with its -delicate and beautiful structure. - -This class of animals is also called /Bryozoa/, and certain species -have the common names of sea-mats and corallines. They are broadly -divided into two groups, namely, the erect and the incrusting forms. -Those having tree- or plant-like shapes resemble seaweeds, while the -colonies which spread over stones, shells, and algae resemble moss, -hence the name /Bryozoa/ (moss-animals). Both groups have the general -appearance of hydroids, because, like them, they are colonies having -plant forms and having their organisms inclosed in cup-like sheaths. -The resemblance, however, is but a superficial one, for the /Polyzoa/ -have a much higher organization, each animal of the colony being a -separate and distinct individual. They can easily be distinguished by -the hair-like processes on the tentacles. The ciliated tentacles and -complete alimentary system are the conspicuous differences between -these colonies and those of the hydroids. - -The /Polyzoa/ are very numerous and form a most attractive [pg192] -group. They are plentiful everywhere, occurring between tide-marks -and at great depths on the floor of the sea. Rocks protected from the -sun are often incrusted with the calcareous forms, while branching -species hang from the rocks and adorn rock pools. /Membranipora/, -in lace-like sheets, will be found on the larger seaweeds as well -as on various submerged objects. The beautiful little /Crisia/ may -be looked for on the fronds of red algae, and /Alcyonidium/, in soft -moss-like patches, on /Fucus/. On some beaches are scattered the -sea-mats, /Flustra foliacea/, looking like bits of brown paper. A -pocket-lens will reveal the marvelous and orderly arrangement of the -two layers of cells, or zo[oe]cia, placed back to back. There is not -a more surprising object in the animal kingdom than a living branch -of /Bugula/. The cells on its spiral, profusely branched clusters -have appendages resembling a bird's head, with its bill constantly -opening and shutting. Of the erect polyzoans some are entirely -calcareous and rigid; such species live in deep water, and their -colonies are called corallines, as are also the calcareous algae. They -have existed in vast numbers since early geologic times, and are -plentiful in the Tertiary deposits, known as Coralline Crags. Other -erect forms have a calcareous framework, which is not continuous, -but has horny intervals, so that the colonies are flexible and can -be swayed by the tides in shallow water where they live. Others -have complete horny exoskeletons. The same differences occur in the -incrusting forms, those on the seaweeds being either flexible, so -that they bend with the plant, or if entirely calcareous are so small -that they do not break when the plant sways to and fro. Still others -are gelatinous and resemble bits of sponge. The calcareous forms are -usually ornamented with ridges which form beautiful patterns. - -The individuals of the polyzoan colonies are small polyp-like -organisms which have a cup-like inclosure of horny or of calcareous -substance, or of the two combined, as mentioned above. This inclosing -sheath is the exterior or cuticle of the animal and is called the -/zo[oe]cium/, the whole colony being called the /zoarium/. The animal -substance within the zo[oe]cium is the /polypide/, and consists of -the mouth, tentacles, and alimentary system. A disk at the anterior -end of the body, bearing the circle of tentacles, is [pg193] the -/lophophore/; it is a contractile body, being, with the tentacles, -protruded from the zo[oe]cium or drawn within it at will. In some -species the orifices of the zo[oe]cia are surrounded with spines; -others have lids, called /opercula/, which shut down when the -polypides are retracted. A singular modification of the zo[oe]cia is -seen in the genus /Bugula/, where peculiar shapes like birds' heads, -called /avicularia/, occur. In these singular appendages the upper -beak is hooked, while the lower one, or mandible, is the operculum of -the zo[oe]cium. These constantly open and shut by means of muscles, -and although their function is not certainly known, it is thought -that they capture prey. Other modifications are whip-like processes, -or flagellate filaments, called /vibracula/, which constantly -beat the water. In many of the zo[oe]cia of the colony there are -dark-colored masses, called /brown bodies/. These are formed by the -degeneration of the polypides, which at certain periods break down, -their tentacles and alimentary system ceasing to act and becoming -brown masses. The body-wall then puts out a bud internally and forms -a new polypide, which absorbs, or passes out, the brown body. The -term of life of a single polypide is not known, but in every colony -many such transformations are constantly taking place. - -The colonies originally start from larvae produced in the /ovicells/ -of the zoaria. The ovicells are sometimes very large and pear-shaped, -occurring at intervals on the stems; or there may be one at the top -of each zo[oe]cium. They look like pearls. A larva, when liberated, -swims about for a time, then attaches itself to a fixed object, and -increases, by budding, into some one of the various forms which the -colonies take. - - -SUBCLASS =ECTOPROCTA= - - -ORDER =GYMNOLAEMATA= - - -SUBORDER ~CYCLOSTOMATA~ - -ERECT OR CREEPING POLYZOA - -The zo[oe]cia are more or less cylindrical; the upper ends are -sometimes completely free and sometimes closely adherent. The -[pg194] opening of the cell has no operculum. Ovicells, containing -the embryos, appear like pear-shaped swellings. - - -GENUS ^Crisia^ - -[Illustration: /Crisia eburnea/; a branch bearing ovicells, highly -magnified.] - - ^C. eburnea.^ This species is found in tide-pools on algae, - especially on the red seaweeds, growing in bushy tufts from one - half of an inch to an inch high. Calcareous, with horny joints; - cells in two rows, semi-alternate, cylindrical, free at one end, - bent; no operculum; ivory-white; ovicells large and pear-shaped. - Common from Long Island Sound northward and on the Pacific coast. - - -GENUS ^Tubulipora^ - - ^T. flabellaris.^ This species is found attached to slender - branched algae, in coral-like masses of long, crooked, tubular - cells united at the base and spreading into fan-shapes placed flat - against the fronds. It is sometimes one quarter of an inch in - diameter. On the same alga may often be found /Crisia/, /Mollia/, - and /Cellepora/. (Plate XLIX.) - - -GENUS ^Diastopora^ - - ^D. patina.^ Tubular cells rise from a saucer-shaped disk about a - quarter of an inch in diameter; cells lie obliquely or stand erect, - and are crowded toward the center; margin of disk without cells; - colony white and calcareous. Found on algae and eel-grass from Long - Island Sound northward. - - -SUBORDER ~CHEILOSTOMATA~ - -In this suborder the zo[oe]cia are either horny or calcareous, and -the orifices are usually surrounded with spines and have opercula. -The orifices generally have raised margins, or peristomes. Ovicells -form helmet-like coverings overhanging the orifices. - - -GENUS ^AEtea^ - - ^AE. anguinea.^ Delicate, white, creeping, calcareous stems, from - which rise numerous club-shaped cells, about one eighth of an inch - high, each one with an aperture in the end. This species creeps in - wavy lines along the fronds of algae, and is frequently found on - /Dasya/, /Griffithsia/, /Plocamium/, and eel-grass. - -[Illustration: PLATE XLIX. Tubulipora flabellaris. 1, Tubulipora -flabellaris, natural size. Eucratea chelata. Cellularia ternata. 1, -Cellularia ternata, natural size.] - -[Illustration: PLATE L. Caberea Ellisii. Bugula turrita. 1, Bugula -Murrayana; 2, B. Murrayana, magnified; 3, B. Murrayana, a few cells, -more highly magnified; 4, B. flabellata; 5, B. flabellata, magnified.] - - -GENUS ^Eucratea^ - - ^E. chelata.^ A small, delicate species rising from a creeping - stem. It has branches composed of single rows of horn-shaped cells - having an oblique aperture on the side. Found at extreme low-water - mark on hydroids, shells, stones, and /Fucus/. (Plate XLIX.) - - -GENUS ^Cellularia^ - - ^C. ternata.^ Zoarium filamentous, spreading, about one inch high, - white, calcareous, branched in a forking manner; cells long, - narrowest at base, arranged in series of three and on the same - plane, apertures oblique and facing one way; horny joint between - each cluster of cells. This species grows in deep water from Cape - Cod northward, and is found on objects washed upon the beach. - (Plate XLIX.) - - -GENUS ^Caberea^ - - ^C. Ellisii.^ Zoarium erect, with fibrous base, leaf-like, branches - in a forking manner; branches straight, stiff, narrow, spreading; - cells arranged in rows of three, adherent throughout; long bristles - emanate from near base of many cells; egg-capsules globular, - smooth, pearly. Common from Cape Cod northward in deep water. - (Plate L.) - - -GENUS ^Bugula^ - -[Illustration: 1, /Bugula turrita/, enlarged; 2, the same, a -branchlet, highly magnified; 3, the same, a branchlet, bearing -ovicells.] - - ^B. turrita.^ This is a very abundant species, found everywhere - along the coast from Maine to North Carolina. Large quantities of - it are [pg196] sometimes thrown upon the beach by storms. It - grows in erect tufts, sometimes a foot long, and is much branched; - the branches grow around the stem in a spiral manner, forming - dense clusters. The lower part of the stem is often naked (having - lost the branches) and bright orange in color, while the tufts of - branches at the top are pearly-white or yellowish. The cells are - long, with a long, pointed spine on the upper outer angle. Like all - species of /Bugula/, it has bird-head appendages, which can be seen - under a powerful glass. (Plate L.) - - ^B. Murrayana.^ Clusters of broad, thin, flexible fronds, one - to two inches high, attached by a slender base and spreading in - entangled masses; fronds wedge-shaped, flat, dividing in a forking - manner; outer cells have bristle-like filaments, which constantly - beat the water; all cells have avicularia, or bird-head appendages. - (Plate L.) - - ^B. flabellata.^ Fan-shaped fronds of flat branches, divided in a - forking manner; the cells are arranged in four or five longitudinal - rows, are oblong, with a spine at each side of the circular - aperture, and are capped with pearl-like ovicells. This species, - like others of the genus, bears the very singular structures known - as avicularia, or bird-head appendages. They show, under a strong - glass, a hooked beak, like that of the hawk or parrot. These beaks - are attached by flexible stems and are provided internally with - powerful muscles by which they are constantly opened and closed; - the beak can bite with considerable force. In this species they are - attached to the sides of the cells. (Plate L.) - - -GENUS ^Flustra^ - - ^F. membranacea.^ This species forms gauze-like incrustations on - the fronds of seaweeds, and is common on /Fucus/ and /Laminaria/, - spreading irregularly over several inches of space. The cells are - oblong, quadrangular, with a blunt, hollow spine at each angle. - Many specimens have simple horny tubes, closed on top, rising from - some of the cells to the height of half an inch. (Plate LI.) - -[Illustration: PLATE LI. Flustra foliacea. 1, 2, Cellepora pumicosa, -natural size; 3, C. pumicosa, magnified; 4, C. ramulosa. 1, Flustra -membranacea; 2, 3, F. membranacea, magnified. Vesicularia dichotoma.] - - -GENUS ^Membranipora^ - - ^M. pilosa.^ An incrusting variety, composed of a single layer of - cells spreading irregularly over the surfaces of stones, shells, - and seaweeds, sometimes completely covering the fronds of /Chondrus - crispus/, /Phyllophora/, /Rhodymenia/, and other algae. The cells - are membranaceous, with a calcareous rim, and have one long hair - and several small ones surrounding the large roundish apertures. It - is found in abundance on the shores from Long Island Sound to the - Arctic Ocean. - - [Illustration: 1, /Membranipora pilosa/; a few of the cells seen - from above, magnified. 2, /Membranipora pilosa/; a single cell, - seen in profile.] - - ^M. lineata.^ Cells oblong, crowded, closely adherent; slender - spines on edge of aperture, which bend over and meet across it; - incrusts rocks and shells in broad, thin, radiating patches; cells - [pg197] much smaller and narrower than those of /M. pilosa/; - easily distinguished from that species by its manner of spreading - and the absence of the one long hair. Common from New Jersey - northward. - - ^M. tenuis.^ Common on pebbles, often covering their whole surface - with a lace-like incrustation of very small oblong cells having a - three-lobed aperture. Found in Long Island Sound and north to Cape - Cod. - - -GENUS ^Escharella^ - - ^E. variabilis.^ This species forms calcareous incrustations on - shells or pebbles. The layers are thin, but eventually overlap one - another, and the incrustation sometimes becomes an inch thick and - resembles coral. The color of the living animal is dull red. The - species ranges from Cape Cod to South Carolina, and is abundant in - Long Island Sound. - - -GENUS ^Mollia^ - - ^M. hyalina.^ Cells subcylindrical, irregular, transparent, smooth, - and more or less oblique. The species forms small circular disks on - algae in tide-pools. - - -GENUS ^Cellepora^ - - ^C. scabra.^ It forms branching, coral-like masses on slender red - algae. - - ^C. ramulosa.^ Branches cylindrical, rough, dividing in a forking - manner, spreading, two to three inches high, calcareous; cells - urn-shaped, irregularly arranged, apertures contracted, long spine - on the outer edge. It is found in deep water attached to shells, - and in tide-pools, where it grows chiefly on /Sertularia/ and other - hydroids and on slender red algae. It ranges from Long Island Sound - to Greenland. (Plate LI.) - - ^C. pumicosa.^ Cells urn-shaped, irregularly crowded together, - forming a conglomeration of porous, brittle masses, not exceeding - an inch in breadth, usually round when small, oblong and knobbed - when large; spine on outer margin of aperture. It incrusts stones - and the stems of /Fucus/. (Plate LI.) - - -SUBORDER ~CTENOSTOMATA~ - - -GENUS ^Alcyonidium^ - - ^A. ramosum.^ Twelve to fifteen inches high; much branched; - branches smooth, cylindrical, one third of an inch in diameter, - usually crooked; branches in a forking manner; color rusty-brown. - Abundant in shallow water, attached to rocks, from New Jersey to - Cape Cod. - - ^A. hirsutum.^ A species common on seaweeds, sometimes completely - covering them, forming dirty, straw-colored, thick, cartilaginous - crusts covered with numerous conical papillae. These are the - cells, or zo[oe]cia; they are surrounded with spines. Circular - yellow spots occur over the surface, which are clusters of eggs. - A good pocket-lens will show the cells, laid in beautiful order, - and perhaps the extended tentacles. Found from Long Island Sound - northward. [pg198] - - ^A. hispidum.^ One of the most common species found incrusting - the fronds of /Ascophyllum/ at low-water mark. It forms fleshy, - brown, soft crusts of moderate thickness, and has spines scattered - over the otherwise smooth and glistening surface. The cells are - inconspicuous, and each one has five long rigid bristles. Habitat, - Long Island Sound to Greenland. - - ^A. parasiticum.^ It forms thin, earthy crusts on algae and - hydroids. The surface is porous; the cells are distant and arranged - irregularly, and seem as if composed of sand cemented with mud. - - -GENUS ^Vesicularia^ - - ^V. dichotoma^ (^Valkeria pustulosa^). This species grows in - clusters of crowded slender stems, which branch in a forking - manner, the branches dividing in different planes, making a - tree-like form one to three inches high. At the points where the - branches divide is a dark, opaque substance, and at these points - also the cells are crowded in clusters of spiral rows and are - greenish-brown in color. The dark spots are in marked contrast to - the white translucent substance of the rest of the stem, giving a - spotted aspect to the whole. (Plate LI.) - - ^V. custata.^ Delicate, thread-like, jointed stems, with slender - opposite branches; cells small and elliptical, arranged mostly - in clusters. Found creeping like a small dodder-plant over other - polyzoans, hydroids, and seaweeds. - - - - -SUBCLASS =ENTOPROCTA= - - -GENUS ^Pedicellina^ - - ^P. americana.^ A very small species. Club-like zo[oe]cia rise - from slender, white, creeping stems; tentacles roll up instead of - retracting into the cups. Found on hydroids, other polyzoans, and - algae. - - - - -V - -ECHINODERMATA - - - - - Phylum - =ECHINODERMATA= - - Classes - =ASTEROIDEA= - (/Starfishes/) - - =OPHIUROIDEA= - (/Brittle-stars/) - - =ECHINOIDEA= - (/Sea-urchins/) - - =HOLOTHUROIDEA= - (/Sea-cucumbers/) - - =CRINOIDEA= - (/Feather-stars and Sea-lilies/) - -[pg201] - - -TERMS USED IN DESCRIBING THE STRUCTURE OF ECHINODERMS - - - ^Abo'ral surface^: The side opposite the mouth. - - ^Ambula'cra^: Tubular feet used in moving. - - ^Ambulacral zones^: The five areas containing the rows of tube-feet. - - ^Ampul'lae^: Reservoirs or vesicles at the base of the tube-feet. - - ^Auricula'ta^: The larval stage of holothurians. - - ^Bipinna'ria^ or ^Branchiolaria^: The larval stage of starfishes. - - ^Dorsal surface^: The back of the animal, generally, but not - necessarily, the upper side. - - ^Exoskeleton^: Outside framework or support, differing from a true - skeleton which lies inside the body. - - ^Interambulacral areas^: The five areas between the ambulacral - zones. - - ^Larva^: The animal in a stage of development from the time it - leaves the egg until it reaches the complete form of the species. - - ^Madreporic plate^: A sieve-like plate of carbonate of lime. - - ^Oral surface^: The side on which the mouth is placed. - - ^Ossicles^: Calcareous plates which cover the body and form the - exoskeleton. - - ^Pedicella'riae^: Small spines which have divided ends, like - scissors or forceps. - - ^Plu'teus^: The larval stage of sea-urchins. - - ^Po'lian vessels^: One to ten sacs arising from the ring-canal. - - ^Ring-canal^: The canal around the mouth. - - ^Spines^: Processes which rise from the surface of the animal. - - ^Stone-canal^: A calcareous tube leading from the madreporic plate - to the ring-canal. - - ^Suckers^: Sucking-disks on the ends of the tube-feet. - - ^Ventral surface^: The side opposite the dorsal surface. - - ^Water-vascular system^: A series of canals which conduct water - through the animal. [pg202] - - - - -ECHINODERMATA - - -The echinoderms, although their shapes are very unlike in the -different classes, have the same general internal structure, and -also other features which place them together in one group. They are -radiates (page 113) of the highest type; they have an exoskeleton; -and many of them are beset with spines, from which the name is given. -They have locomotor organs, the /ambulacra/, and a /water-vascular -system/ peculiar to themselves. Some have the very strange power of -casting off, and developing again, parts of the body. - -The development from the egg to the adult is remarkable, and of -unusual interest to naturalists. The larval stage of echinoderms -is so unlike the mature animal that for a long time the larvae were -thought to be another class of animals, and therefore were given the -names which they still retain. - -In observing echinoderms it will be seen that the dorsal part is -carried uppermost by some, such as the starfishes and sea-urchins. -In the former the back is broad and extended; in the latter it is -curved and contracted. But in crinoids the back is carried downward -and is extended like a stalk; in the sea-cucumbers (holothurians) -the dorsal and ventral surfaces are parallel with the long axis of -the cylindrical body, instead of being on a plane with the mouth and -excretory opening. Owing to the unusual positions of the dorsal and -ventral surfaces, the terms /oral/ (mouth side) and /aboral/ (side -opposite the mouth) are generally used in describing these species. - -The surface of the body is divided definitely by the ambulacra, the -/ambulacral zones/, and the /interambulacral spaces/, but differently -in the different classes. The movement of the animals is [pg203] -effected by means of the tube-feet, or ambulacra. These have suckers, -which are attached or released by the power of the water-vascular -system. The /madreporic plate/, which can be distinctly seen in -starfishes at the angle of two of the arms, is a calcareous porous -plate which opens into the /stone-canal/. This canal passes through -the body and opens into a circular tube which runs around the -mouth. A system of canals extends from this circumoral tube, or -/ring-canal/, and eventually one canal opens into each tube-foot. -Water, entering by the madreporic plate, passes through the various -canals and into the tube-feet, which it distends. When the feet are -pressed against a substance and the water is withdrawn, a vacuum is -formed, which causes the disk-ends of the feet to act like suckers. -When the feet are again flooded the hold is relaxed. Thus the animal -drags its body along with a slow, gliding motion. The madreporic -plate, being calcareous, is said to act as a filter, purifying the -water as it passes into the body, which it furnishes with oxygen as -well as with locomotive power. - -[Illustration: Aristotle's lantern.] - -A curious organ found in the /Echinoidea/ (sea-urchins) is called -/Aristotle's lantern/. It is a complicated arrangement, not fully -understood, having forty parts, and is connected with the alimentary -system. One of the parts is the mouth, over which five teeth project. -These teeth grasp and grind the food. The exoskeleton is composed -of plates of carbonate of lime, called /ossicles/, which cover the -surface of the body. The ossicles are of various sizes and shapes, -and are one of the determining features in classification. They may -be scattered spicules of lime, separated plates joined by connecting -rods, or overlapping plates; or they may be fitted together so as to -form a continuous shell. The starfishes are usually carnivorous, the -sea-urchins usually vegetarian, while the holothurians, after the -manner of worms, take in sand and mud, deriving their nourishment -from the organic particles contained in them. All echinoderms live in -the sea. [pg204] - - -TABLE SHOWING THE CLASSIFICATION OF THE STARFISHES DESCRIBED IN THIS -CHAPTER. - - Class =ASTEROIDEA= (/Starfishes/) - - Order =PHANEROZONIA= (/Ossicles not crowded; large marginal - ossicles; spines only on dorsal surface; pedicellariae sessile/) - - Families Genera Species - - ~PORCELLANASTERIDAE~ ^Ctenodiscus^ ^C. corniculatus^ - - ~ASTROPECTINIDAE~ ^Astropecten^ ^A. articularis^ - ^Psilaster^ ^P. florae^ - ^Luidia^ ^L. senegalensis^ - ^L. clathrata^ - ^L. alternata^ - - ~PENTAGONASTERIDAE~ ^Mediaster^ ^M. aequalis^ - - ~ANTHENEIDAE~ ^Hippasteria^ ^H. phrygiana^ - - ~PENTACEROTIDAE~ ^Pentaceros^ ^P. occidentalis^ - ^P. reticularis^ - ^Nidorella^ ^N. armata^ - - ~ASTERINIDAE~ ^Asterina^ ^A. folium^ - ^A. miniata^ - - Order =CRYPTOZONIA= (/Ossicles crowded; pedicellariae stalked/) - - ~SOLASTERIDAE~ ^Solaster^ ^S. endeca^ - ^S. decemradiata^ - ^Crossaster^ ^C. papposus^ - - ~ECHINASTERIDAE~ ^Cribrella^ ^C. sanguinolenta^ - ^Echinaster^ ^E. sentus^ - - ~HELIASTERIDAE~ ^Heliaster^ ^H. multiradiata^ - - ~ASTERIIDAE~ ^Asterias^ ^A. vulgaris^ - ^A. Forbesii^ - ^A. ochracea^ - ^A. gigantea^ - -[pg205] - - - - -CLASS =ASTEROIDEA= - -THE STARFISHES - - -These animals are named from their star-shaped outline. Some have -five long, spreading arms diverging from a small disk, which is -hardly more than their point of union; others have a large body with -short arms, which are like angular projections of the body, giving -a pentagonal shape. Some genera have a greater number of arms than -others; /Solaster/ has eleven to thirteen, and /Heliaster/ (the -sun-stars, found on the west tropical coast) has thirty to forty. - -[Illustration: Diagram of water-vascular system of a starfish: /a/, -madreporite; /b/, stone-canal; /c/, ring-canal; /d/, radial canals; -/e/, ampullae; /f/, ambulacra.] - -The mouth of the starfish is in the center of the ventral side. A -ventral or /ambulacral groove/ extends through each arm. In these -grooves the ambulacra, or tube-feet, are arranged in rows. The -/ambulacra/ are hollow, cylindrical bodies, each of which has a -sucker at one end, and is connected at the other end with a little -globular body, the /ampulla/. The ventral groove forms a ridge in the -body-cavity. It is called the /ambulacral zone/, and is formed by a -double row of elongated plates, which meet and form a raised line -along the middle of the inside of the arms, and appear like ribs; -between them lie the ampullae. These plates are called the /ambulacral -ossicles/. Numerous other ossicles extend over the surface, buried -in the integument of the body, making a calcareous network, or -/exoskeleton/. The ossicles are connected by muscles so that the -animal is not rigid, but is able to bend the body and even creep -through comparatively small places. The ossicles are covered with -/spines/ of two kinds. The very minute ones are the /pedicellariae/, -and have a jointed end which opens and shuts like a pincers. Their -principal use seems to be to remove waste matter or other substances -from the body, keeping it free and clean. The pedicellariae are -arranged, in some species, in circles around the [pg206] bases -of the spines, and form groups over the dorsal surface. Examining -the backs of different starfishes with a strong magnifying-glass, -one will be surprised to see the varied grouping of the spines and -pedicellariae. At the extremity of each arm is a red eye-spot, which -is sensitive to light, and a tube-foot, which has no sucker and which -is believed to act both as an olfactory and as a feeling organ. The -madreporic plate lies at the angle of two of the arms or rays. Water -filters through the madreporic plate and passes by the stone-canal to -the ring-canal around the mouth, and thence to the radial tubes, one -of which extends through each arm and is connected by a branch with -each tube-foot. At the base of each tube-foot there is a globular -reservoir, or ampulla. A valve connects the tube-foot and ampulla. -When the ampulla is contracted, water is forced into and distends -the tube-foot; when the ampulla is distended, it withdraws the water -from the tube-foot, thus acting like a suction-bulb. When water -is sent into the tube-feet they are greatly extended and are then -placed against an object. The water being then withdrawn through the -ampullae, a vacuum is formed, and the suckers are tightly attached. -By the alternating movements of the ambulacra the animal is dragged -slowly along and moves with a gliding motion. It does not deviate -from a straight path, going over elevations or through depressions -without turning aside; its body conforms to the irregularities of -the road and never bridges over spaces. The stomach extends a little -way into the arms, and a short intestine leads to the excretory -opening in the center of the back. Starfishes are carnivorous and -voracious, and are particularly [pg207] destructive to oyster-beds. -The animal fastens itself to a bivalve, and protrudes a part of its -stomach, with which it envelops its prey and slowly sucks it out of -its shell. When feeding on small mollusks they take them into the -stomach directly. Starfishes regain by natural growth parts of the -body which may be lost. Sometimes the animal throws off an arm to -escape capture, and self-mutilation also occurs where unfavorable -conditions exist. Oystermen formerly were ignorant of the starfish's -wonderful powers of regeneration, and were in the habit of cutting -up those captured in their forks and throwing them overboard, thus -increasing the number instead of destroying their enemies, as each -arm with a piece of the body attached to it will, it is said, become -a new individual. This tenacity of life makes starfishes difficult -to destroy, and they are exceedingly plentiful in all seas. One -naturalist speaks of seeing on the coast of Maine a bed of starfishes -which extended several miles and covered the bottom so closely that -he picked sixty individuals off a small stone. On the northern -shores of the Pacific coast they abound in great variety, and some -are of unusual size. /Asterias gigantea/ of this region measures -two feet across. Another species, /Phyncopodia helianthoides/, -measures a yard in diameter, and has twenty or more arms. The most -common species of the Atlantic coast are /Asterias vulgaris/ and /A. -Forbesii/; the former ranges from Long Island northward, the latter -from Massachusetts to Florida. These are the species particularly -destructive to oyster-beds. /Asterias vulgaris/ sometimes grows to be -fifteen inches in diameter; from this, which is perhaps the largest, -are found starfishes of all sizes down to the very small /Cribrella/. -They inhabit all varieties of bottoms, from low-water mark to deep -water. They are not always abundant in the same place, but seem to -move about. - -Some oystermen believe that the starfishes get into masses like a -ball and are rolled along by the tide. This idea comes from the fact -that an oyster-bed may be free from them one day and the next be -covered by these pests. To get rid of them the beds are swept over -with a tangle, which is an iron bar holding swabs of raveled rope. -The spines of the starfish are caught in the [pg208] tangle, and -often hundreds are brought up in one haul and are then killed by -steaming. - -The anatomical system of the starfish is easily traced by cutting -off, with scissors, the skin from the dorsal surface of the disk, and -also cutting a slit down one of the arms. In the center of the body -will be seen the upper part of the stomach, a small star-like spot, -from which radiate five branches, which divide and lead into the -much-ramified, plume-like organs which extend through the arms. These -are the pyloric caeca, whose function is to secrete the digestive -fluids. The much-folded stomach occupies the greater part of the -central space, its large convolutions showing on top. The mouth -connects with the stomach on the ventral side. By turning back the -skin from the arm, small filiform processes can in some large species -be seen; these are the dermal branchiae, or breathing-organs, which -may either project through pores in the skin between the ossicles or -be entirely retracted. If the pyloric caeca be laid back, one can see -the rib-like arrangement of the ambulacral ossicles, and also the -ampullae, which lie between the ossicles on each side of the ridge. If -an ampulla be inflated and then pressed, the corresponding tube-foot -will be seen to extend. To follow successfully the water-vascular -system, beginning in the madreporic plate and extending through the -stone-canal to the ring-canal around the mouth and thence through the -arms, requires a strong glass and more skilful manipulation. - - -ORDER =PHANEROZONIA= - - -FAMILY ~PORCELLANASTERIDAE~ - - -GENUS ^Ctenodiscus^ (Plate LII.) - - ^C. corniculatus.^ Pentagonal; about two and a half inches in - diameter; the body flat, with wide marginal plates, giving a - flat edge to the rather long, pointed arms; madreporic plate - large; color greenish; ambulacra without suckers, seeming to be - adapted to pushing through soft mud rather than dragging over hard - surfaces. It lives in deep water on muddy bottoms and ranges from - Massachusetts to Greenland. When dredged the animal is usually - found to be filled with soft mud. - - -FAMILY ~ASTROPECTINIDAE~ - -In this family there are only two rows of tube-feet; the rays end in -sharp points and have large ossicles on the margins. [pg209] - - -GENUS ^Astropecten^ - - ^A. articularis.^ The body is flat and smooth; the rays sharply - pointed and conspicuously bordered with marginal ossicles and - fringed with short spines; two rows of ambulacral feet; color rich - purple. Found in shallow waters of South Atlantic coast on sandy - bottoms. (Plate LII.) - - -GENUS ^Psilaster^ - - ^P. florae.^ Diameter four to five inches; arms sharply pointed - and conspicuously bordered with large ossicles; body flat, with - smooth surface, the ossicles seeming like mosaic; bright pinkish - flesh-color. It occurs in deep water off the eastern coast as far - south as New Jersey. - - -GENUS ^Luidia^ - -This genus of starfishes is celebrated for its peculiar habit of -breaking in pieces when taken from the water, and therefore good -specimens are almost impossible to obtain. - - ^L. senegalensis.^ Twelve to fourteen inches across; arms long and - narrow, tapering to a point and fringed on the edges with spines; - surface rather smooth, showing the separation of the ossicles; - color almost white, with dark line running through the center of - each arm; usually nine arms. Found in shallow water on the coasts - of Florida and the Gulf of Mexico. - - ^L. clathrata.^ Four to five inches across; light-colored; with - a fringe of spines on the margins of the arms, which taper to - a point; two rows of ambulacra. It is found from New Jersey - southward, and is one of the most common starfishes on the sandy - beaches of North and South Carolina. (Plate LII.) - - ^L. alternata.^ Upper surface purplish, with irregular yellowish - bands on the arms; under surface yellow. Found in shallow water on - the Florida coast. - - -FAMILY ~PENTAGONASTERIDAE~ - - -GENUS ^Mediaster^ - - ^M. aequalis.^ Body flat; the five rays equal or exceed in length - the diameter of the disk; margins have double row of large plates; - surface covered with granules, which are easily rubbed off; bright - red above, pale orange below; diameter four inches. Common on the - coasts of Oregon and California. - - -FAMILY ~ANTHENEIDAE~ - - -GENUS ^Hippasteria^ - - ^H. phrygiana.^ This beautiful starfish lives in deep water, but - is sometimes thrown up on the beach, and ranges from Cape Cod - northward. [pg210] It has a large, pentagonal, bright-scarlet - disk, five to six inches in diameter, with arms rather long and - pointed. The upper side is raised and cushion-like, and is covered - with blunt spines; the margins have larger spines of the same - shape. The pedicellariae are sessile and so long and large as to be - easily seen with the naked eye. (Plate LII.) - - -FAMILY ~PENTACEROTIDAE~ - - -GENUS ^Pentaceros^ - - ^P. occidentalis.^ Pentagonal; eight to twelve inches in diameter; - ossicles a network of rod-like plates, with prominent spines at - the points of union; body inflated in the center and running in - wedge-like form to the ends of the rather long and narrow arms; the - upper lines of the ridges have spines more prominent than those - on the rest of the body; the spines of the larger specimens are - more like large warts or small hemispheres. Found on the Lower - California coast. - - ^P. reticularis.^ This starfish is the largest species on our - coasts. It is common in southern Florida close to the shore. The - body is three to four inches thick, flat on the oral surface, but - raised on the upper side, and tapers down in wedge-like form to the - points of the short arms. The prominent blunt spines which cover - its surface are arranged in a somewhat regular net-like order, and - the sharp-edged margins have an even row of larger spines of the - same form. The madreporic plate is nearly in the center of the - disk, and is quite conspicuous, being bordered with a circle of - small spines. Its color is dull yellow, and its size often a foot - or more in diameter. It is the large starfish so often seen in - curiosity-shops. (Plate LII.) - - -GENUS ^Nidorella^ - - ^N. armata.^ This very curious pentagonal species, found on the - California coast, is five to six inches in diameter and red in - color. The upper surface is raised and covered with thick, pointed - spines one half of an inch to one inch long, arranged in lines, but - not crowded. The ossicles on the margins are large; some of them - are hemispherical and bear large spines. Smaller spines border the - under edge of the margins. (Plate LIII.) - - -FAMILY ~ASTERINIDAE~ - -The starfishes of this family are pentagonal, with a large body and -short arms. The disk is more or less elevated in the center, and the -edges are sharp. There are two rows of ambulacra. The ossicles are -notched and overlapping. The family is confined to temperate and -tropical waters. - - -GENUS ^Asterina^ - - ^A. folium.^ Small, pentagonal, swollen (gibbous). Found on the - Florida coast. - -[Illustration: PLATE LII. Ctenodiscus crispatus. Astropecten -articularis. Luidia clathrata. Hippasteria phrygiana. Pentaceros -reticularis.] - -[Illustration: PLATE LIII. Nidorella armata. Asterina miniata. -Solaster decemradiata. Crossaster papposus.] - - ^A. miniata.^ Pentagonal; somewhat raised in center; about one and - a half inches across; edges sharp. Found on the California coast - close to shore. (Plate LIII.) - - -ORDER =CRYPTOZONIA= - - -FAMILY ~SOLASTERIDAE~ - - -GENUS ^Solaster^ - - ^S. endeca.^ Dark red in color; nine to eleven arms, which are - shorter than the breadth of the disk; diameter of disk about five - inches; two rows of ambulacra; surface rather smooth. Common on - the coast of Maine, and found from Cape Cod to Newfoundland below - low-water mark. - - ^S. decemradiata.^ This species is common on the North Pacific - coast. It has ten arms, which are about twice the length of the - diameter of the body, the whole body being about a foot across. - (Plate LIII.) - - -GENUS ^Crossaster^ - - ^C. papposus.^ Twelve to fifteen arms, half as long as the breadth - of the body; upper surface an open network of calcareous rods, - or ossicles; at their points of union are club-shaped tubercles - bearing tufts of smaller spines; concentric lines and spots of red - and purple over the spiny upper surface; color light underneath. - Common on the New England coast. (Plate LIII.) - - -FAMILY ~ECHINASTERIDAE~ - - -GENUS ^Cribrella^ - - ^C. sanguinolenta.^ This species is abundant north of Cape Cod and - is found of all sizes from half an inch to two inches in diameter - and of various colors--purple, orange, red, yellow, flesh-color, - etc. It has five round arms, generally about four times as long as - the breadth of the disk. The ends are often turned upward. It is - covered with crowded short spines, like little warts, which give - it a nearly smooth surface. It has two rows of ambulacra. It moves - with two of its arms turned forward, as if they were dragging the - other three behind them. Unlike most species, the young are not - free-swimming, but the eggs are carried around the mouth of the - mother, and the young are retained there until they are capable of - taking care or themselves. (Plate LIV.) - - -GENUS ^Echinaster^ - - ^E. sentus.^ This species occurs close to shore in the waters of - Florida and is perhaps the most commonly observed species on the - beach. It extends as far north as New Jersey. It is purplish in - color, and about four and a half inches in diameter, with two rows - of ambulacra, five arms, and a surface rough with spines. [pg212] - - - -FAMILY ~HELIASTERIDAE~ - - -GENUS ^Heliaster^ - - ^H. multiradiata.^ Spines on the upper surface of rays in five - rows, but close to the disk proper become reduced to one row. Found - on the coasts of Lower California and Mexico. (Plate LIV.) - - -FAMILY ~ASTERIIDAE~ - -The /Asteriidae/ have the following characteristics: four rows -of tube-feet; ossicles small and unequal; spines isolated or -grouped; pedicellariae of two forms, forceps-like and scissors-like -respectively. They include the very common forms found on all beaches. - - -GENUS ^Asterias^ - - ^A. vulgaris.^ The common starfish of the Atlantic coast, from - Long Island Sound to Labrador. It occurs at low-water mark and - extends into deep water. It has five arms, which taper to a point. - Large specimens measure fifteen inches across. The upper surface - is rough, being covered with short spines, which are largest and - thickest at the edges of the rays, and surrounding them are the - pedicellariae. The color varies from pink, yellow, and brown to - purple. - - ^A. Forbesii.^ The common starfish of the Atlantic coast, from - Massachusetts Bay to the Gulf of Mexico. This species resembles - very closely /A. vulgaris/, but can be distinguished from it by - the madreporic plate, which is bright orange, while in the former - it has the same color as the animal; also the arms are a little - swollen at the base and terminate more bluntly. These two species - are very destructive to oyster-beds, especially where their ranges - overlap. It is computed that they destroy annually two hundred - thousand dollars' worth of oysters. Vast numbers congregate where - the feeding-ground is good, and move in long lines from place - to place. The oystermen dredge over the beds and bring them up - in thousands, then steam them or throw them on the shore above - high-water mark. (Plate LIV.) - - ^A. ochracea.^ The common starfish of the Pacific coast, from - Sitka to San Diego. Five rays, each hardly twice as long as the - diameter of the body; spines running irregularly over the surface, - but forming a pentagon at the middle of the disk and inclosing the - madreporic plate; diameter eight inches. It is very common near San - Francisco on rocks at low-water mark. (Plate LIV.) - - ^A. gigantea.^ Body very large and swollen; six rays, somewhat - less in length than twice the diameter of the disk; aboral surface - covered with numerous short, blunt, equidistant spines of uniform - size and regularly distributed; spines contracted at the base and - striated; diameter two feet. Found on the California coast. - -[Illustration: PLATE LIV. Cribrella sanguinolenta. Heliaster -multiradiata. Asterias Forbesii. Asterias ochracea.] - - -TABLE SHOWING THE CLASSIFICATION OF THE BRITTLE-STARS DESCRIBED IN -THIS CHAPTER. - - Class =OPHIUROIDEA= (/Brittle-stars/) - - Order =EURYALIDA= (/Skin without plates; arms simple or branched, - and capable of being rolled up/) - - Genera Species - - ^Astrophyton^ ^A. Agassizii^ - - Order =OPHIURIDA= (/Skin with plates/) - - ^Ophiopholis^ ^O. aculeata^ - ^Amphiura^ ^A. squamata^ - ^Ophiocoma^ ^O. riisei^ - ^O. aethiops^ - ^O. Alexandri^ - ^Ophiothrix^ ^O. angulata^ - -[pg214] - - - - -CLASS =OPHIUROIDEA= - -BRITTLE-STARS - - -The ophiurans, or brittle-stars, differ from the starfishes in having -the arms quite distinct from the body. In starfishes the arms are -extensions of the body, and the viscera extend partway into them, -while in ophiurans the body is a central disk, with the five narrow -arms attached to its margin. In form they suggest a spider, and -sometimes are called sea-spiders. The name brittle-star is also -descriptive, since they break off their limbs readily. The arms are -narrow, taper to a point, usually curl at the ends, and have no -ambulacral grooves, but are completely covered with bare calcareous -plates (except in the first order, where they have a skin and no -plates). The ambulacra are small spines without suckers, which -emanate from the sides or margins of the arms and do not serve for -walking. The madreporic plate is on the ventral surface, in one of -the circular shields which surround the mouth. The alimentary canal -ends blindly. The egg-sacs lie between the arms and open by slits on -the under side, close to the arms, where they join the disk. Water -flows in and out of these pouches, which are thought to have also -respiratory and excretory functions. No eye-specks have been found, -but they must exist, since the animal is sensible to approaching -danger and quickly retreats. The ophiurans are more active than -starfishes, moving by wriggling, and clambering with their arms. They -are shy and hard to find, and it is difficult to capture a whole one, -since they throw off pieces of their arms at the least alarm. Often -they completely dismember themselves, an action which does them no -permanent injury, since they reproduce lost parts. They are more -commonly inhabitants of deep than of shallow waters, and are brought -up from the bottom in dredges in great numbers. [pg215] Some species -may be found near low-water mark under stones and in clusters of -mussels, and often in seaweeds, thrown up from deep water, on the -shore. - - -ORDER =EURYALIDA= - - -GENUS ^Astrophyton^ (Plate LV.) - - ^A. Agassizii.^ This very singular ophiuran is commonly called the - basket-fish, from its resemblance to a basket when the tentacles - are rolled up. Its body is covered with skin instead of calcareous - plates. The body is thick and somewhat circular in form, with - elevated radiating ridges on the upper side, and the skin is marked - off in star-like divisions. From the margin of the body extend - five arms, which at once divide in a forking manner; each section - again divides, and this division in pairs (dichotomous division) - continues until the ends of the arms have become very numerous and - attenuated. The arms are carried curled up or straight at will. In - moving, the animal seems to walk on these branches as if on tiptoe, - and in this position it forms a kind of net which entraps prey. The - arms and prominent parts of the disk are yellow, and the depressed - or membranous parts brown. /Astrophyton/ is six to eighteen inches - in diameter. It is found off the northern New England coast. - - -ORDER =OPHIURIDA= - - -GENUS ^Ophiopholis^ - - ^O. aculeata.^ This is a common species, found in shallow water - on the North Atlantic coast. A similar or perhaps identical - species occurs on the North Pacific coast. It is spotted purple or - variegated in color. The upper surface of the body is covered with - plates variously arranged, sometimes in the shape of a star, and - each one is surrounded with small spines. The under side of the - egg-sacs is covered with small spines. These sacs open by slits on - each side next the arms, and have a rounded appearance, bulging - out between the arms. The arms, which are long and attenuated at - the ends, have on the upper side transverse oval plates surrounded - by a border of flat, roundish granules. Sometimes the plates are - divided into two or three pieces, when they are similarly bordered - with granules. The arms are fringed with rows of thick, compressed, - obtuse spines, generally six in each row. The under sides of the - arms have large quadrangular plates slightly separated from one - another and extending across the whole surface in regular, even - rows. (Plate LV.) - - -GENUS ^Amphiura^ - - ^A. squamata.^ This very delicate species, found on shelly bottoms - below low-water mark from New Jersey northward, has a body less - than one quarter of an inch in diameter, with arms two inches or - more [pg216] in length and thread-like in size. These long, - slender arms have, on both the upper and under surfaces, a row of - overlapping plates, and are fringed with small spines, three in a - row. The color is gray or whitish, sometimes marked with darker - gray or brown. (Plate LV.) - - -GENUS ^Ophiocoma^ - - ^O. riisei^, ^O. aethiops^, ^O. Alexandri^. These animals have - long spines on the sides of the arms, which give them a bushy - appearance. The surface of the body is granulated, but the arms - are covered with wide plates. Their color is brown above and light - beneath. /O. riisei/ is found at Key West, the other two species on - the coast of Lower California. (Plate LV.) - - -GENUS ^Ophiothrix^ - - ^O. angulata.^ Body covered with short, rough spines; egg-sacs - conspicuous and extend like lobes between the arms; rays narrow and - thickly beset with long spines, which are serrated on the edges and - ends. Found on the Florida coast. (Plate LV.) - -[Illustration: PLATE LV. Astrophyton. Ophiocoma aethiops Ophiothrix -angulata. Ophiopholis aculeata. Ophiocoma Alexandri. Amphiura -squamata.] - -[pg217] - - -TABLE SHOWING THE CLASSIFICATION OF THE ECHINOIDEA DESCRIBED IN THIS -CHAPTER - - =Class= =ECHINOIDEA= - - Order =DESMOSTICHA= or =REGULARIA= (/Shell usually globular; mouth - and anus polar; lantern of Aristotle present/) - - Families Genera Species - - ~CIDARIDAE~ ^Cidaris^ ^C. tribuloides^ - ^Dorocidaris^ ^D. papillota^ - ^D. Blakei^ - ^Porocidaris^ ^P. sharreri^ - - ~ARBACIADAE~ ^Arbacia^ ^A. punctulata^ - ^C[oe]lopleurus^ ^C. floridanus^ - - ~DIADEMATIDAE~ ^Diadema^ ^D. setosum^ - - ~ECHINOMETRIDAE~ ^Echinometra^ ^E. subangularis^ - - ^Strongylocentrotus^ ^S. drobachiensis^ - ^S. purpuratus^ - ^S. franciscanus^ - - ~ECHINIDAE~ ^Echinus^ ^E. gracilis^ - ^Toxopneustes^ ^T. variegatus^ - - Order =CLYPEASTROIDEA= (/Corona or shell a more or less flattened - disk; anus excentric; lantern of Aristotle present/) - - ~ECHINANTHIDAE~ ^Clypeaster^ ^C. ravenellii^ - ^Echinanthus^ ^E. rosaceus^ - - ~SCUTELLIDAE~ ^Echinarachnius^ ^E. parma^ - ^E. excentricus^ - ^Mellita^ ^M. testudinata^ - ^Encope^ ^E. michelini^ - - Order =SPATANGOIDEA= or =PETALOSTICHA= (/Heart-shaped; mouth and - excretory opening excentric; no lantern of Aristotle/) - - ~SPATANGOIDAE~ ^Moira^ ^M. atropos^ - ^Lovenia^ ^L. cordiformis^ - ^Schizaster^ ^S. fragilis^ - ^Metalia^ ^M. pectoralis^ - ^Brissopsis^ ^B. lyrifera^ - -[pg218] - - - - -CLASS =ECHINOIDEA= - -SEA-URCHINS, CAKE-URCHINS, HEART-URCHINS - - -ORDER =DESMOSTICHA= - -SEA-URCHINS - -The shell of a sea-urchin consists of many calcareous plates, -or /ossicles/, fitted closely together and forming a continuous -exoskeleton. The plates are so united that externally the marks of -juncture are not perceptible, but on the interior the shape of these -plates is well defined. In examining such a shell, or test (they -abound on the beach), it will be seen that its surface is covered -with numerous hemispherical projections or knobs, which are grouped -in double rows and run in meridional lines from one pole to the -other of the more or less spherical body, separating it into ten -divisions. Five of these divisions have perforations, or small pores -in the plates of the shell, and are called the /ambulacral zones/ -or areas, because through these pores pass the small tubes, in the -living animal, which connect the tube-feet, or /ambulacra/, with the -radial water-canals and the /ampullae/ (see page 206). The wide spaces -between these double rows of pores are called the /interambulacral -zones/ or areas. The ten spaces diverge from the /peristome/, or -soft part around the mouth, in the center of the lower surface, and -converge in the small area at the top or aboral side. In the center -of this small circular dorsal space is the excretory opening, and -surrounding it are ten plates, five of which have openings into the -egg-sacs. One of them is larger than the others, and is modified to -form the /madreporic plate/. The other five plates have eye-specks. -The ambulacral zones terminate at these ocular plates. - -The numerous spines which cover the animal are of three [pg219] -kinds, and proceed from the knobs on the exoskeleton, over which they -fit, forming ball-and-socket joints, which enable them to move in -any direction. The long spines are ribbed, and seem to have no other -function than that of protection. The second set, the /pedicellariae/, -are very peculiar small organs scattered over the surface in great -numbers, and consisting of a head bearing three bill-like blades -mounted on a long, flexible stalk. The office of some of the -pedicellariae is to remove waste from the excretory opening; this is -passed down regular lines and dropped into the water, thus keeping -the body clean. Others are constantly opening and shutting their -forks, reaching in all directions and grasping and removing anything -which may have become entangled in the spines. They also capture -floating bits of seaweed, which they drag over the body to conceal -it. A third set of projections are the /sphaeridia/, small globular -bodies said to be connected with perception. - -[Illustration: Test of sea-urchin, with the spines removed to show -the arrangement of the plates, lateral view: /Amb/, ambulacral zone -with its perforated plates; /Ap/, apical (aboral) pole; /Int. amb./, -interambulacral zones. (From Bronn's "Thierreich.")] - -The spines vary greatly in size, number, and form in different -species, and are such conspicuous features as to make the -identification of species easy. In some the spines are solid and -fluted; [pg220] in others they are hollow, sharp, and brittle; again -in others they are short and silky, or very long and serrated, and so -on. In one species they are so broad and flat as to resemble little -sails. (See /Dorocidaris/.) (Plate LVI.) - -The mouth, over which five long teeth project, is a part of -Aristotle's lantern, which forms a curious and prominent feature in -the center of the lower surface. Ten tentacles, like large tube-feet -without suckers, lie around the mouth. The alimentary canal, starting -in Aristotle's lantern, winds in two and a half coils around the -inside of the shell, supported by mesenteries, and terminates in the -excretory opening on the aboral surface. The sea-urchin has also -a water-vascular system similar to that of starfishes (page 206). -When the tube-feet are distended they project beyond the spines, and -enable the animal to move slowly about; but sea-urchins are less -active than starfishes, and although they are so well protected by -spines and have few enemies after maturity, they lie in sluggish -idleness in secluded places, and for further concealment often cover -themselves with seaweeds or stones. - -The sea-urchin has a nervous system, which starts in a ring around -the mouth, ramifies through the body, and terminates in the -eye-plates. The tube-feet and all the spines are under nervous as -well as muscular control. Egg-sacs lie under the apex of the shell -and open by separate ducts into the five plates on the small upper -disk. Through these the eggs are discharged into the water, where -they become free-swimming larvae, called /Pluteus/. This immature -sea-urchin (Pluteus) undergoes several curious transformations in -the course of its development, and does not in any way resemble the -mature animal. In spring the apical disk of the females will often -be found covered with orange-colored ova, and that of the males with -white sperms. In the growth of the animal, in its mature form, the -shell enlarges by accretions of lime on the individual plates, or -ossicles, of the exoskeleton, and by new plates formed around the -apical disk. Sea-urchins are compared to starfishes folded over, the -eye-specks on the ends of the rays meeting in a small area around -the excretory opening, the ambulacra following spherical lines and -leaving the mouth, as before, on the ventral side. [pg221] - -The /Echinoidea/ present great differences in shape, being more or -less spherical, oval, discoid, and heart-shaped. These variations are -associated with the differences of internal structure, the openings -of the digestive tract being at the opposite poles in the spherical -and oval forms, but excentric in the disk- and heart-shaped species. -The sea-urchins are grouped in three orders in accordance with these -variations. All are characterized by the absence of arms, by having -the calcareous plates immovably united to form a firm test, and by -the great development of the movable spines upon the plates. - -Sea-urchins are sometimes called /sea-eggs/, perhaps from their -shape, but possibly from the edible quality of some species, which -are eaten by the natives of the shore, who take them at the spawning -season, when the egg-sacs are distended. They are gregarious, and -frequently are so crowded together as literally to pave the surface -of rocks and the bottoms of tide-pools in sheltered places. The -following is quoted from A. Agassiz: "Many of the /Desmosticha/ -along coasts exposed to the action of the waves live in cavities -which they hollow out of the solid rock. This they do, not by means -of any solvent, but by mere mechanical action. They chisel out with -their teeth the solid rock by incessant turning round and round, and -keep their cave, where they are frequently prisoners for the rest -of their existence, up to the size required by the growth of their -test and spines, by constant gnawing. On the coast of California the -common /Strongylocentrotus purpuratus/ occurs in this way. We find -long tracts of shore, where this sea-urchin is common, completely -honeycombed and pitted by cavities and depressions in which they seek -shelter against the powerful surf continually beating against the -rocks. The same species does not excavate in sheltered places, where -the sea-urchins can find protection between the interstices of large -fragments of rock or ledges more or less sheltered from the more -direct action of the open sea." - -Sea-urchins in cavities of granite rock, where the openings are too -small for the animal to get out, are to be seen in thousands on the -coast of France at Croisic, Lower Loire. Spines of large sea-urchins -are used as slate-pencils by the missionaries in the Pacific -Islands. [pg222] - - -FAMILY ~CIDARIDAE~ - - -GENUS ^Cidaris^ - - ^C. tribuloides.^ Similar to /Porocidaris sharreri/, but with - thicker and stouter spines. Found from South Carolina to Brazil. - - -GENUS ^Dorocidaris^ - - ^D. papillota.^ A deep-water species which occurs off Chesapeake - Bay and southward. It has slender spines with distinct longitudinal - rows of serrations, and the spines are grouped in rosette-like - forms over the small spherical body. - - ^D. Blakei.^ This species is very peculiar in having broad, - fan-shaped spines; vermilion in color. Found in deep water in the - Bahamas and West Indies. (Plate LVII.) - - -GENUS ^Porocidaris^ - - ^P. sharreri.^ This species occurs, in deep water, off the coast of - North Carolina and thence southward to the West Indies. The shell - is light greenish-pink. The spines are white, with brownish-pink - at the base, pointed, three and a half inches long, and surrounded - at the base with small, flat, triangular, secondary spines. (Plate - LVII.) - - -FAMILY ~ARBACIADAE~ - - -GENUS ^Arbacia^ - - ^A. punctulata.^ A small species found in shallow water on shelly - and gravelly bottoms from Massachusetts to Mexico, and common - in Long Island Sound. The shell is about one inch in diameter; - the spines are rather thick and one half to three quarters of an - inch long. The color varies from deep violet--almost black--to - straw-color, and the spines are tipped with brown. The South - Carolina species are usually brick-red in the bare interambulacral - spaces, with darker sutures, and spines tipped with same color. The - animal walks by means of its spines, with a tilting motion, and - advances quite rapidly. (Plate LVII.) - - -GENUS ^C[oe]lopleurus^ - - ^C. floridanus.^ This beautiful sea-urchin is taken on the Florida - reefs. The very brittle spines are one to four inches long, and - are banded with carmine and white. The shell has zones of light - chocolate-color alternating with orange and yellow. - - -FAMILY ~DIADEMATIDAE~ - - -GENUS ^Diadema^ - - ^D. setosum.^ Spines very brittle, and from one to two and a half - inches long; jet-black. Found on the Florida reefs. (Plate LVII.) - - -[Illustration: PLATE LVI. Pedicellariae of sea-urchins. Spines of -sea-urchins.] - -[Illustration: PLATE LVII. Porocidaris sharreri. Dorocidaris -Blakei. Arbacia punctulata. Diadema setosum. Strongylocentrotus -franciscanus.] - - -FAMILY ~ECHINOMETRIDAE~ - -In this family the ambulacral plates have several pairs of pores. - - -GENUS ^Echinometra^ - - ^E. subangularis.^ This species, which ranges from South Carolina - to Brazil, and is also found in Bermuda, is common on mud-flats - and is easily distinguished by its oblong or elliptical shape. - Its shell is about three inches long in its widest portion. The - spines are one half of an inch to one inch long, thick at the base - and tapering to a point. The color is dark purplish-green to deep - violet--almost black. - - -GENUS ^Strongylocentrotus^ - - ^S. drobachiensis.^ This sea-urchin (which bears, perhaps, the - longest name in technical nomenclature and has no other, unless - that of "sea-egg," which is applied indiscriminately to all - sea-urchins) is a very common species in shallow waters of the - northern temperate zones. It extends as far as New Jersey on the - Atlantic and to the State of Washington on the Pacific coast. - Although it is found as far south as New Jersey, it is there rare - and small; but farther north, especially on the coast of Maine, - it is exceedingly abundant. It is green or greenish-purple in - color, and resembles somewhat a large chestnut-bur. The body is - circular, somewhat depressed (but of variable thickness), and - about two inches in diameter. The spines are moderately slender - and longitudinally striated. It feeds partly on diatoms and other - small algae, which it cuts from the rocks with its sharp teeth. It - also devours dead fishes, bones and all, and in return is swallowed - whole by the wolffish and other large fishes. It moves by means - of the tube-feet on its oral surface, slowly dragging itself - along, and frequently is seen with seaweed, a stone, or some other - substance on its back, which it places there with its pedicellariae - for the purpose of concealment. - - ^S. purpuratus.^ The common purple sea-urchin of the west coast, - from Sitka to Lower California, found in abundance on the rocks - just beyond low-water mark. It is about one and a half inches in - diameter, with rather thick, pointed, and fluted spines. - - ^S. franciscanus.^ This is the largest species of the west coast, - the shell measuring sometimes five inches across, and the thick - spines one and a half inches in length. The tubercles on the naked - shells are very prominent, and the zones are very clearly marked. - It is purple in color and is often found in great quantities at - low-water mark. It ranges from Alaska to Lower California. (Plate - LVII.) - - -FAMILY ~ECHINIDAE~ - -In this family the ambulacral plates have but three pairs of pores. -[pg224] - - -GENUS ^Echinus^ - - ^E. gracilis.^ This is a deep-water species, which occurs from - Cape Cod southward. The shell is nearly spherical, but is a - little depressed on the oral side, and has twenty bands of color, - alternately green and white. The spines are short and thin. - - -GENUS ^Toxopneustes^ - - ^T. variegatus.^ This is the common species of the Southern States, - from North Carolina southward, and is found in shallow water in - protected places. The shell is nearly globular; the spines vary in - thickness and color, some being long, slender, and greenish, while - others have stout and blunt spines of a yellowish or violet tint. - - -ORDER =CLYPEASTROIDEA= - -CAKE-URCHINS - -The animals of this order, commonly known as sand-cakes or -sand-dollars, are flat and circular like disks. Sometimes they are -cut at intervals on the margin; again they have slits through the -body (/lunules/). They have a well-marked star-shaped figure on the -dorsal surface. This figure is formed by the ambulacra, or tube-feet, -which run in five rounded or petal-shaped lines on the under surface. -The mouth, in Aristotle's lantern, is in the center of the somewhat -concave ventral surface, the petal-like ambulacral zones meeting at -the central space. The excretory opening is on the margin of the -disk, at a point between two of the sections of the star-like figure. -This marks the posterior part of the body, while the opposite arm -of the star marks the front or anterior end. The spines are very -fine and silky, and are spread abundantly over the whole animal. -Clypeasteroids are mainly found in sand considerably below low-water -mark, though some species thrive where they are exposed to the surf -on open sandy beaches. - - -FAMILY ~ECHINANTHIDAE~ - - -GENUS ^Clypeaster^ - - ^C. ravenellii.^ This species occurs in deep water from South - Carolina southward. The disk is about four inches in diameter, - and is raised [pg225] in the center into a large cone. The - ambulacra run down the sides of the cone in straight lines, and - around the base is a depressed area which emphasizes a thick border - which extends around the scalloped margin. The color is light - yellowish-brown. (Plate LVIII.) - - -GENUS ^Echinanthus^ - - ^E. rosaceus.^ This is a large species, oblong in shape, about - four to five inches across and much rounded on top, the body being - about two inches thick. The ambulacral zones are depressed, leaving - prominent elevations which make a very conspicuous figure on the - top. The color is light chocolate-brown. Found close to the shore - off the coasts of Florida, South Carolina, and the West Indies. - - -FAMILY ~SCUTELLIDAE~ - - -GENUS ^Echinarachnius^ - -THE SAND-DOLLARS - - ^E. parma.^ This species, the shells of which are very common - objects on sand-beaches from New Jersey northward, is generally - known as the sand-dollar. The animals have flat circular disks - about three inches in diameter. The ambulacral zones, in five - petal-like lines, form a distinct figure on the upper surface. The - mouth is in the center of the ventral surface, and the excretory - opening is on the edge of the disk. In life they are covered - with short, fine, silky spines, which seem like hair, and are - purplish-brown in color, but turn green when taken from the water. - The sand-dollars are exceedingly abundant off Nantucket Shoals, - where the bottom seems paved with them. They are eaten in great - numbers by flounders, cod, and haddock. When put in alcohol they - stain it a dark color. Fishermen prepare an indelible ink by - grinding to powder these animals and mixing it with some liquid. - This species is also found on the northern Pacific coast. - - [Illustration: /Echinarachnius parma/, the sand-dollar. Much - smaller than natural size.] - - ^E. excentricus.^ This is the common sand-dollar of the Pacific - coast. The disk, instead of being circular as in /E. parma/, is - somewhat straight across the posterior end, and the posterior - ambulacral zones are shorter than the other three. The upper side - of the disk is raised, forming a cone-like elevation, the apex - being the center of the figure. - - -GENUS ^Mellita^ - - ^M. testudinata.^ The disk is rounded in front and straight in the - back. Four long, narrow lunules, or cuts, occur on the sides in - line with the ambulacral, petal-shaped zones, but do not extend - quite to the edge of the disk; and a wide lunule occurs in the - interambulacral space [pg226] of the posterior end. The three - anterior zones are shorter than the posterior pair. On the upper - side of the disk the spines all turn toward the periphery. The - color of the living animal is greenish-blue. It is very abundant - from Cape Hatteras southward in shallow water, and the shells are - sometimes found as far north as Cape Cod. (Plate LVIII.) - - -GENUS ^Encope^ - - ^E. michelini.^ Ambulacral zones unequal in size, the posterior - pair usually longer than the others; lunules like notches in the - margin, with a large one opening between the posterior ambulacral - zones nearly in the center of the disk; disk rounded in front and - square at the back. Common on the coasts of southern Florida and - the Gulf of Mexico in shallow water. (Plate LVIII.) - - -ORDER =SPATANGOIDEA= - -HEART-URCHINS - -The /Spatangoidea/, or heart-urchins, have heart-shaped or thick -elliptical bodies. The mouth and excretory opening are both away from -the center and on the ventral side. These animals seem deformed, so -much are they out of symmetry and so different in outline from the -other orders of the class. The ambulacral zones are in circles, or -petaloid in outline, as in cake-urchins, but are not continuous, and -the anterior one is usually unlike the others and frequently without -pores. The entire body is covered with spines, and these are the -chief organs of locomotion; the greater part of them turn backward, -giving the living animal the semblance of a porcupine. The mouth is -protected by a projecting plate, but Aristotle's lantern is absent -in this order. The anatomy is in general the same as in the other -orders, but the organs are turned in conformity with the inclosing -shell. Most of these animals bury themselves in sand or mud and live -in deep water; a few only are littoral species. - - -FAMILY ~SPATANGOIDAE~ - - -GENUS =Moira= - - ^M. atropos.^ Size about one inch by one and a half inches, and one - inch thick; color yellowish-white, with brown spines. Found from - North Carolina to Florida, from the shore to deep water. - -[Illustration: PLATE LVIII. Clypeaster ravenellii. Mellita -testudinata. Encope michelini. Test of Metalia pectoralis. Lovenia -cordiformis.] - -[pg227] - - -GENUS ^Lovenia^ - - ^L. cordiformis.^ About one inch by one and a half inches thick; - reddish in color; resembles a little porcupine. Found on the - southern California coast. (Plate LVIII.) - - -GENUS ^Schizaster^ - - ^S. fragilis.^ One and a half by two inches in size, and one inch - thick; color brownish. Lives in deep water off the eastern coast. - - -GENUS =Metalia= - - ^M. pectoralis.^ A very large heart-urchin, found on the southern - coast of Florida and in the West Indies in shallow water. It is, - perhaps, the largest species found, being six to eight inches long - and proportionately wide and thick. The shell is thin, more or less - elliptical, and densely clothed with long reddish-gray spines. - (Plate LVIII.) - - -GENUS ^Brissopsis^ - - ^B. lyrifera.^ A beautiful deep-water species, found off the - coasts of Florida and the Gulf of Mexico. It has a red body with - pale-yellowish spines. In size it is about two by two and a half - inches, and is thickest on the posterior end. It is thickly clothed - with long curved spines, some of which form two long tufts in the - back. [pg228] - - -TABLE SHOWING THE CLASSIFICATION OF THE HOLOTHUROIDEA DESCRIBED IN -THIS CHAPTER - - Class =HOLOTHUROIDEA= - - Order =ELASIPODA= (/Deep-sea forms; tube-feet in zones near - together/) - - Order =PEDATA= (/Well-developed tube-feet and false ambulacra/) - - Genera Species - - ^Thyone^ ^T. briareus^ - ^Pentacta^ ^P. frondosa^ - ^Lophothuria^ ^L. fabricii^ - - Order =APODA= (/Without radial canals, tube-feet, or respiratory - trees/) - - ^Synapta^ ^S. tenuis^ - ^S. roseola^ - ^S. rotifera^ - ^Caudina^ ^C. arenata^ - -[pg229] - - - - -CLASS =HOLOTHUROIDEA= - -SEA-CUCUMBERS - - -The holothurians, or sea-cucumbers, although in appearance quite -unlike starfishes and sea-urchins, have the characteristic ambulacral -zones and other features of the group. In form they are cylindrical, -and, when the tentacles and tube-feet are retracted, resemble fat -worms; when fully expanded they are somewhat like sea-anemones, the -tentacles forming a rosette-like top. The walls of the body are tough -and muscular, with small calcareous deposits or spicules of various -shapes in the skin. The mouth is at one end, the excretory opening -at the other, and along the body are double rows of tube-feet. Often -instead of tube-feet, or together with them, are conical processes -without suckers. The ambulacra, when arranged in regular zones, are -used for locomotion only in the lines running from the madreporic -plate. In some species three of the zones are near together, and form -a kind of sole on which the animal creeps; again the tube-feet are -wholly suppressed, as in /Synapta/. Besides progressing by means of -these suckers, the holothurians move, as do worms, by the extension -and contraction of the body. The inner surface of the tough membrane -inclosing the body is lined with powerful longitudinal and transverse -muscles, by means of which the creature contracts and lengthens its -body and changes its form in a wonderful manner. Around the mouth -are tentacles, which are often much branched and are used as organs -of touch and smell, and sometimes have an ear-sac at the base. From -the mouth the food-canal, making one long coil, extends to a chamber - [pg231] (/cloaca/) at the other pole. The cloaca gives off a pair -of much-branched respiratory trees, which are constantly supplied -with water by the contractions of the cloaca. At the base of one of -the respiratory trees are singular structures known as /Cuvierian -organs/. They are numerous, viscid, glandular tubes, which the animal -can throw out, and which will adhere closely to almost anything. The -holothurian has a water-vascular system, the madreporic plate being -near the mouth, but not opening to the outside, and a nervous system -which starts from a ring which lies around the mouth. The egg-sacs -are branched tubes, often highly colored, which open to the outside, -close to the wreath of tentacles surrounding the mouth. - -[Illustration: Internal organs of a /Holothurian/, as seen when -the body-wall is divided along the middle of the dorsal surface: -/b.w./, body-wall; /circ. mus./, circular layer of muscle; /cl./, -cloaca; /cl. op./, cloacal opening with five teeth; /cuv. org./, -Cuvierian organs; /gen. ap./, genital aperture; /gen. du./, genital -duct; /gen. gl./, genital gland; /int./, intestine; /inter. oss./, -interambulacral ossicles; /int. ves./, intestinal vessels; /long. -mus./, longitudinal band of muscle; /mad. can./, madreporic canals; -/mes./, mesentery; /pol. ves./, Polian vesicles; /rad. amb./, radial -ambulacral vessel; /ri. bl. ves./, ring blood-vessel; /resp./, -respiratory trees; /ring-ves./, ring-vessel of the ambulacral system; -/stom./, stomach.] - -The larvae, when free-swimming, are called /Auricula/. In the -deep-water species, /Cucumaria crocea/ and /Psolus ephippiger/, the -eggs, when discharged, and the young are carried on the back of the -mother. In /Cucumaria laevigata/ there is a brood-pouch, while in -/Synapta viviparia/ the young develop in the body-cavity. - -The holothurians have the singular power of ejecting the whole of -their internal organs and of growing them again in case they escape -the enemy they have endeavored to elude by this strange method. They -also turn themselves inside out, as it were, as if from /nausea/, -when confined in water too stale for their uses. Often the viscera -are ejected through holes in the sides of the body broken by violent -muscular contractions. - -Holothurians are generally distributed through all seas, but are -congregated in greatest numbers in Eastern seas. Their habitat -extends from shallow to very deep water. They are found in -tide-pools, on rocks, and in sand or mud. Like worms, they live on -organic particles contained in mud and sand, which they take into the -gullet and pass through the alimentary canal. - - -ORDER =PEDATA= - - -GENUS ^Thyone^ - - ^T. briareus.^ This is a large purple holothurian, found in shallow - water from Texas to Cape Cod. It is four to five inches long and - one inch or more thick, purple in color, and thickly covered over - its whole surface with prominent papillae. [pg232] - - -GENUS ^Pentacta^ - -[Illustration: /Pentacta frondosa/, the sea-cucumber.] - - ^P. frondosa.^ This animal is commonly called the sea-cucumber, - and the popular name somewhat expresses its form, but it has the - power of changing its shape in a most surprising manner. Sometimes - it will be nearly globular, again long and thin, or it may be - constricted like an hourglass. When at rest the body is ovate and - somewhat pentagonal. On the angles are double lines of suckers, and - in the interambulacral zones are a few scattered false ambulacra. - The surface is nearly smooth, very dark purple on one side, and - inclined to whitish on the other. Ten much-branched tentacles - surround the mouth. The animal, when grown and expanded, measures - fifteen to eighteen inches in length. This species is found - throughout the whole length of both the east and the west coasts. - It is very plentiful on the Maine coast in tide-pools and on the - rocks at low-water mark. The genus ranges over the greater part of - the globe. The tough muscular body is said to be edible, tasting - somewhat like lobster, or trepang (/Holothuria edulis/), which is - found on coral reefs in Eastern seas and is much valued as food - by the Chinese. The internal organs of /P. frondosa/ are highly - colored, making its anatomy easy to trace. The muscular system is - plainly defined. - - -GENUS ^Lophothuria^ - -[Illustration: /Lophothuria fabricii/, showing under surface with -three rows of ambulacra.] - - ^L. fabricii^ (Verrill), ^Psolus fabricii^ (Dueben), ^Cuvieria - squamata^ (D. and K.: Agassiz). The body in this species is covered - with rounded overlapping scales and numerous granulations, and - when it is retracted is about two and a half to three inches long - and about one inch thick. [pg233] Rows of tube-feet lie near - together, on a flat under surface, and form a kind of sole on which - the animal creeps. The oral end of the body is a little raised - and bears ten tentacles; these tentacles are profusely and finely - branched, and when expanded are about as long as the body. The - aboral end is obtuse and a little raised. Around the oral and anal - openings the scales are grouped, forming circles in those regions. - This holothurian is bright red in color, and when expanded is a - beautiful object, perhaps the most attractive in appearance of any - in the class. When retracted it has the aspect of an ascidian, and - for a time was supposed to belong to that group. It is found on the - New England coast on the under side of large shelving rocks. - - -ORDER =APODA= - - -GENUS ^Synapta^ - - ^S. tenuis.^ This curious animal is long and slender, and so - transparent that its internal organs are clearly visible. Around - the mouth are a circular tube and a wreath of twelve branching - tentacles. There are no ambulacra. Little spots scattered - irregularly over the surface show, when highly magnified, small - warts, each one of which has a calcareous projection shaped like a - little anchor. By means of these anchors and by the contractions - of its body the animal moves through the mud or sand in which it - lives, near low-water mark. The sand is collected into rings at the - oral end and pushed downward until the whole animal is inclosed in - a sand-tube. When empty /Synapta/ is white and transparent, and - the digestive canal may be seen wound in a spiral throughout its - length; but when gorged with food, sand, pebbles, and shells can - be distinctly seen filling the food-canal, and the body then has a - dark-gray color. /Synapta/ grows to a length of eighteen inches or - more, but is constantly breaking pieces off its posterior end by - muscular contractions. When kept in confinement it soon commences - to constrict its body at various points, and after a few hours - there is nothing left but a mass of fragments. It is viviparous, - that is, it carries its young in the body-cavity; the eggs are - hatched, and the young approach maturity before they are expelled. - This species ranges from Cape Cod to North Carolina, and can be - found in the upper part of its burrows when the tide is out. - - ^S. roseola.^ This species occurs in the same localities as /S. - tenuis/, and differs from it mainly in color, which is pale red, - due to minute red spots scattered through the skin. - - ^S. rotifera.^ A species found in Florida. It is light purplish - in color, and has eight or ten branches on each of the twelve - tentacles. In this species the spicules of lime in the skin are - shaped like wheels instead of anchors. - - -GENUS ^Caudina^ - - ^C. arenata.^ About four inches long and tapers to the ends; the - posterior end sometimes narrowed to a long, slender, tail-like - extremity; tentacles around the mouth resemble cloves. It lives in - sand and may be found on the New England coast, washed ashore after - a storm. [pg234] - - - - -Class =CRINOIDEA= - -Genera ^Pentacrinus^ ^Comatula^ - - - - -CLASS =CRINOIDEA= - -FEATHER-STARS AND SEA-LILIES - -[Illustration: The feather-star (/Antedon/), illustrating the -/Comatula/ form of crinoid.] - -The crinoids are inhabitants of deep water, where they grow in great -numbers, forming beds of sea-lilies. Their general form, which -suggests the lily, and their feather-like manner of branching, give -them the two common names of sea-lilies and sea-feathers. They have -a long, jointed stalk, one end of which is attached, while the other -bears the disk of the animal. From the disk emanate five arms, which -divide near the base, making [pg235] ten arms in all. The arms -have short branches along the sides. Ambulacral grooves follow the -center of all the arms and branches. The mouth is in the center of -the upper side, which in this case is the ventral surface. The genus -^Pentacrinus^ remains permanently attached, but ^Comatula^, at a -certain stage of development, separates from the stalk and swims -freely about by means of its arms. It can attach itself temporarily -by tubular processes, which are developed on the dorsal surface at -the point where the stem was attached. The ossicles, or plates which -cover the dorsal surface, are free, making the crinoid an animal of -innumerable joints. - -[Illustration: /Pentacrinus asteria./] - -The crinoids are particularly interesting from the fact that they -have existed from early geologic times, and their history is written -in stone. In the early ages they were the only class of echinoderms, -and their evolution into other forms can be traced through successive -geologic periods. They existed in such vast numbers that the fossil -forms are plentiful and are familiar to every student of geology, and -are known as stone-lilies and encrinites. To-day they are decadent, -there now remaining only twelve of the two hundred genera which -existed formerly. A fine bed of crinoids is found off Cuba, on the -slope of the coast where the water rapidly deepens from one hundred -to two hundred fathoms. [pg236] - -Although the crinoids are deep-water forms, and are never found on -the beach, they are given here because they follow in the system of -classification and illustrate another curious class of echinoderms. -The brief description given may add interest to the fossil forms to -be seen in museums. - - - - -VI - -ARTHROPODA - - -TABLE SHOWING THE CLASSIFICATION OF THE ARTHROPODS DESCRIBED IN THIS -CHAPTER - - Phylum =ARTHROPODA= - - Class =CRUSTACEA= - - Subclass =Entomostraca= (/Crustacea of small, often of almost - microscopic minuteness, and of comparatively simple - organization; appendages have little differentiation/) - - Order =PHYLLOPODA= (/Appendages resemble leaves; mostly - fresh-water species/) - - Suborder ~EUPHYLLOPODA~ (/Phyllopoda of considerable - size, bearing ten to sixty pairs of leaf-like - swimming-feet/) - - Suborder ~CLADOCERA~ (/Small phyllopoda; body laterally - compressed; carapace like a bivalve shell; four to five - pairs of swimming-feet; chief organs of locomotion are - the biramous antennae; abdomen devoid of appendages. They - abound in fresh water, are very prolific, and afford a - large amount of food to fresh-water fishes/) - - Genera Species - - ^Daphnia^ - ^Leptodora^ - ^Moina^ - ^Polyphemus^ - - Order =OSTRACODA= (/Resemble minute bivalve shells; swim by - antennae; body unsegmented; appendages seven pairs only/) - - ^Cypris^ (fresh-water) - ^Cypridina^ (marine) - - Order =COPEPODA= (/Small size; body long, segmented; four to - five pairs of once-branched appendages on thorax; abdomen - without appendages; abundant in fresh and salt water; many - forms parasitic/) - - ^Cyclops^ - ^Cetochilus^ - ^Sapphirina^ - ^Siphonostomata^ - ^Nicothoe^ - - Order =CIRRIPEDIA= (/Imperfectly segmented; fixed or - parasitic during adult life; inclosed in skin strengthened - by calcareous plates; abdomen rudimentary; appendages - biramous, usually six pairs/) - - Genera Species - - ^Lepas^ ^L. anatifera^ - ^L. striata^ - ^L. pectinata^ - - ^Balanus^ ^B. balanoides^ - ^B. eburneus^ - ^B. rugosus^ - ^B. geniculatus^ - ^B. tintinnabulum^ - - Suborder ~RHIZOCEPHALA~ (/Parasitic/.) - - ^Sacculina^ (parasitic on crabs) - ^Peltogaster^ (parasitic on hermit-crabs) - - Subclass =Malacostraca= (/Highly organized Crustacea, usually - of considerable size; appendages much differentiated/) - - Order =PHYLLOCARIDA= (/Small; covered with bivalved carapace; - thoracic feet leaf-like; abdominal feet biramous; posterior - segment terminates in two long spines; mostly fresh-water - species/) - - Order =SCHIZOPODA= (/Small; transparent; shrimp-like; thorax - more or less completely covered with soft carapace; - thoracic appendages biramous; eyes on stalks/. /Mysis/ are - /Without gills or thoracic legs/; /Euphausia/ are /With - gills or thoracic legs/.) - - ^Mysis^ ^M. sternolepis^ - ^Euphausia^ - - Order =DECAPODA= (/Thoracic segments unite with head and form - cephalothorax, which is covered by carapace; eyes stalked; - maxillipeds have exopodites; five pairs of walking-feet - without exopodites/) - - Suborder ~MACRURA~ (/Abdomen usually longer than - cephalothorax and commonly extended; rostrum usually - prominent; eyes not inclosed in orbits; antennae and - antennules large; antennae have exopodites/) - - Set Free-swimming Forms: Shrimps and Prawns - - ^Penaeus^ ^P. setiferus^ - ^P. brasiliensis^ - ^Palaemonetes^ ^P. vulgaris^ - ^Crangon^ ^C. vulgaris^ - ^C. franciscorum^ - - Families Genera Species - - Set Creeping Forms: Lobsters and Crawfish - - ASTACOIDAE ^Homarus^ ^H. americanus^ - ^Panulirus^ ^P. interruptus^ - ^P. argus^ - ^Scyllarus^ - - Set Anomalous Forms: Approaching the Brachyura - - Suborder ~ANOMURA~ (Of these Families, the Lithodidae have - /Fifth pair of feet folded under the carapace/) - - DROMIDAE ^Hippoconcha^ ^H. arcuata^ - - PAGURIDAE ^Pagurus^ ^P. bernhardus^ - ^P. pollicaris^ - ^P. longicarpus^ - ^Clibanarius^ ^C. vittatus^ - ^Pylopagurus^ - - CENOBITIDAE ^Cenobita^ ^C. diogenes^ - - HIPPIDAE ^Hippa^ ^H. talpoida^ - ^H. analoga^ - ^Albunaea^ ^A. gibbesii^ - - PORCELLANIDAE ^Porcellana^ ^P. sayana^ - ^P. sexspinosus^ - ^Petrolisthes^ ^P. armatus^ - - LITHODIDAE ^Lithodes^ ^L. maia^ - ^Echidnocerus^ ^E. cibarius^ - ^E. foriminatus^ - ^Acantholithodes^ ^A. hispidus^ - ^Cryptolithodes^ ^C. sitchensis^ - ^Phyllolithodes^ ^P. papillosus^ - - Suborder =BRACHYURA= (/Abdomen shorter than cephalothorax, - and permanently folded under it; eyes inclosed in orbits; - antennules and antennae small/. Of these Families, the - PORTUNIDAE are called /Swimming crabs/; the OCYPODIDAE are - called /Sand- and fiddler-crabs/; and the MAIIDAE are the - so-called /Spider-crabs/.) - - Families Genera Species - - PORTUNIDAE ^Carcinides^ ^C. maenas^ - ^Callinectes^ ^C. sapidus^ - ^Ovalipes^ ^O. ocellatus^ - - Set WALKING CRABS - - CANCROIDAE ^Cancer^ ^C. irroratus^ - ^C. borealis^ - ^C. magister^ - ^C. productus^ - ^C. antennarius^ - ^Menippe^ ^M. mercenaria^ - ^Eupanopeus^ ^E. herbstii^ - ^Eurypanopeus^ ^E. depressus^ - ^Neopanopeus^ ^N. texana^ - ^Rhithropanopeus^ ^R. harrisii^ - - GRAPSIDAE ^Hemigrapsus^ ^H. nudus^ - ^H. oregonensis^ - ^Pacygrapsus^ ^P. crassipes^ - - OCYPODIDAE ^Ocypoda^ ^O. arenaria^ - ^Uca^ ^U. minax^ - ^U. pugnax^ - ^U. pugilator^ - - MAIIDAE ^Libinia^ ^L. dubia^ - ^L. emarginata^ - ^Hyas^ ^H. coarctatus^ - ^H. lyratus^ - ^H. araneus^ - ^Loxorhynchus^ ^L. crispatus^ - ^Pugettia^ ^P. gracilis^ - ^Sternorhynchus^ ^S. sagittarius^ - ^Epialtus^ ^E. productus^ - ^Pitho^ ^P. aculeata^ - ^Lambrus^ ^L. pourtalesii^ - - CALAPPIDAE ^Calappa^ ^C. flamma^ - - PINNOTHERIIDAE ^Pinnotheres^ ^P. ostreum^ - - Order =STOMATOPODA= (/Abdomen very large; second pair - of thoracic legs very large; gills borne on abdominal - segments/) - - ^Squilla^ ^S. empusa^ - - Order =CUMACEA= (/Small, shrimp-like/) - - ^Diastylis^ ^D. quadrispinosus^ - - Order =ARTHROSTRACA= (/No carapace, as a rule; six to seven - pairs of walking-legs; eyes sessile/) - - Suborder ~AMPHIPODA~ (/Body usually compressed laterally/) - - ^Orchestia^ ^O. agilis^ - ^Talorchestia^ ^T. longicornis^ - ^Gammarus^ ^G. locusta^ - ^Chelura^ ^C. terebrans^ - ^Caprella^ ^C. geometrica^ - - - Suborder ~ISOPODA~ (/Body depressed or flattened/) - - ^Cirolana^ ^C. concharum^ - ^Limnoria^ ^L. lignorum^ - ^Sphaeroma^ ^S. quadridentatum^ - ^Idotea^ ^I. marina^ - ^I. ochotensis^ - ^I. metallica^ - ^I. wosnesenskii^ - ^Chiridotea^ ^C. caeca^ - ^C. entomon^ - - Class =MERISTOMES= - - Order =XIPHOSURA= - - ^Limulus^ ^L. polyphemus^ - - Class =PANTOPODA= (Lang) - - Order =PYCNOGONIDA= - - ^Phoxichilidium^ ^P. maxillare^ - -[pg243] - - -TERMS USED IN DESCRIBING CRUSTACEA - -^Abdomen^: The posterior part of the body. - -^Antennae^: Articulated appendages which immediately precede the mouth. - -^Anten'nules^: The anterior of the two pairs of feelers of the head. - -^Bira'mous^: Having two branches. - -^Carapace^: A thin chitinous shell covering the cephalothorax. - -^Cephalic^: Pertaining to the head. - -^Cephalotho'rax^: The united head and thorax. - -^Chela^: The pair of pincers, or claw, which terminates some of the -appendages. - -^Che'liped^: A leg with chela, or claw, at the end. - -^Endop'odite^: The inner one of the two main divisions of the limb. - -^Epime'ra^: Divisions on the ends of the segments of amphipods and -isopods, and belonging to the legs. - -^Epip'odite^: A third branch of a limb. - -^Epis'toma^: A triangular area in front of the mouth. - -^Exop'odite^: The outer one of the two main branches into which the -typical limb of any segment is divided. - -^Gastric mill^: The first half of the stomach, where food is ground. - -^Mandibles^: The pair of appendages next behind the antennae. - -^Maxil'lae^: The first pair of appendages after the mandibles. - -^Maxillipeds^: The three pairs of appendages after the maxillae. - -^Metame'res^: Segments. - -^Orbits^: Eye-cavities, peculiar to the higher /Crustacea/. - -^Prosto'mium^: The region in front of the mouth; the preoral part of -the head. - -^Rostrum^: The beak in front of the head. - -^Segment^: A part cut off or marked as separate from others. - -^Somite^: A segment of the body. - -^Squame^: A scale. - -^Telson^: The last segment of the abdomen. - -^Thorax^: The middle part of the body. - -[pg244] - - - - -ARTHROPODA - - -This subdivision of the animal kingdom includes insects, centipedes, -spiders, and crustaceans, which together constitute more than -half the known species of animals. Although these animals are so -unlike in general appearance, it is easy to recognize the common -characteristics which place them together in one group. The name -/Arthropoda/, meaning "jointed-footed," suggests perhaps one of the -most obvious points of resemblance. The /Arthropoda/ have bilateral -symmetry, one side of the body being like the other; they are covered -with a horn-like material (chitin); they are divided into segments; -the segments have appendages; and the appendages are jointed so as -to admit freedom of motion. Their manner of growth is peculiar; they -cast off their rigid external coverings and secrete larger coats of -mail, and at these periods increase in size or undergo metamorphosis. - -There are such modifications of these general features as the habits -of the different species demand. For instance, the appendages may be -constructed for walking, swimming, boring, sucking, or the seizure -and preparation of food. In some animals the appendages form a part -of the breathing-organs, in others are used as organs of sense. Every -detail of the organism, down to the hairs, has its special use and -function. - - -CLASS =CRUSTACEA= - -The crustaceans vary in size from microscopic minuteness to two feet -or more in length. The giant crab of Japan (/Kaempferia kaempferi/) -exceeds this, being commonly from eight to twelve feet [pg245] -across the arms, and is said to reach even greater proportions. -Crustaceans live on land and sea, and in both fresh and salt water; -they may be parasitic, sedentary, or free and active. There are said -to be over ten thousand species, which include crabs, lobsters, -shrimps, beach-fleas, wood-lice, barnacles, and water-fleas. Nine -tenths of the species are marine; of these some are pelagic, and -their transparent forms constitute a part of the plankton. Others -live on the bottom in deep water and attain a large size. A vast -number live in the littoral zone and form a considerable part of that -crowded community. They are scavengers and freebooters, being great -fighters, as well as predatory in their habits. As a rule, they feed -on dead organic matter, which they consume in surprising quantities; -some have also a vegetarian diet. They have, like starfishes, the -singular power of throwing off their limbs and growing new ones. - -The /Crustacea/ derive their name from the nature of their crust or -covering. This is earthy and brittle, not stony, like the shells -of mollusks. This crust, or exoskeleton, has various degrees of -firmness, from that of a delicate polished cuticle, seen in small -forms, to the heavy armor of some crabs and the shell-like character -of the covering of barnacles. - -The lobster and crab are perhaps the most comprehensive examples as -well as the largest in size of the class, the vast majority of the -species being minute forms. The ocean swarms with varieties too small -to be noticeable to the naked eye. - -It is the province of /Crustacea/ to consume decaying organic matter, -both animal and vegetable, and in doing this they perform a great -service in purifying the waters of the pool, the shore, and even the -sea. Not only in this are they serviceable, but to a great extent -they serve as food for other animals, their flesh being palatable -and preferred to that of other animals whose diet would seem to make -them more wholesome. The small forms exist in such myriads, and -increase so rapidly, that, although extremely small, they furnish an -inexhaustible supply of food. Even some whales subsist upon these -minute animals, and for man the larger species are articles of diet -that are counted among the luxuries. The crustaceans are remarkable -for their varied forms and for their [pg246] perfect adaptation to -many different conditions of life. There is no class in the animal -kingdom which presents so wide a range of organization, or whose -structure deviates so widely from the type form. These differences -lie chiefly in the external characters and in the structure of the -appendages. - -Some species are solitary, like lobsters and crabs; others, like -shrimps, are gregarious and live in immense shoals. In the habits of -these animals there is much which excites wonder and interest. - - -ANATOMY OF THE HIGHER CRUSTACEA - -The body of a crustacean is divided into segments, which are -sometimes distinctly separated, like joints, and sometimes fused -into one piece. The head part is called the /cephalic/ portion, -the middle section is the /thorax/, and the posterior part is the -/abdomen/. The horn-like covering of the thorax is the /carapace/; -where it projects over the head it is the /rostrum/. When the head -and thorax are united, as in most /Crustacea/, the anterior or front -portion of the animal is called the /cephalothorax/. Each segment -has a pair of appendages. Each appendage has a joint attached to the -body; from this arise two jointed branches, the /endopodite/ and -the /exopodite/, the inner and the outer foot. The appendages are -modified to perform special functions. In front of the mouth are two -pairs: the smaller ones are the /antennules/ and have ears at the -base; the larger ones are /antennae/ and are feelers. At the base of -the antennae are the /green glands/, said to have renal functions. -Both the antennules and the antennae are fringed with hairs, which aid -in the sense of touch and perhaps of smell. On each side of the mouth -are the /mandibles/. Then come the /maxillae/ and the /maxillipeds/, -used in capturing and tearing the food and conveying it to the mouth. -Thus it will be seen that some of the appendages around the head -are connected with the senses, and others are used in eating. Those -of the thorax are for walking; those of the abdomen for swimming, -guarding the eggs, etc. The food taken into the mouth passes into -the stomach through a short passage. The stomach is divided into two -parts. The front [pg247] one contains three long teeth which meet -laterally and grind the food; this is known as the /gastric mill/. - -When sufficiently fine, the food passes through a strainer of stiff -bristles into the smaller portion of the stomach, where it is -partially digested, and from there enters a long, straight intestine -which reaches the length of the body and opens to the outside on -the under side of the /telson/, or last segment. A large liver also -pours its secretions into the intestine. The green substance commonly -called "fat" in lobsters is the liver. - -The heart consists of an elongated tube, or a short sac, which lies -directly under the integument of the back. From this heart-sac, -blood, which is colorless, is sent by arteries to all parts of the -body; it then collects in spaces called /venous sinuses/, from which -it goes to the gills, and thence back to the heart. - -The nervous system begins in a large ganglion in front of the mouth, -called the brain; from this two branches arise, which pass on each -side of the digestive organs, meeting in ganglia in each segment -and extending the whole length of the body. The gills, by which the -animal breathes, are upon the limbs, or on the walls of the body -immediately adjacent to them, and are generally inclosed in special -chambers. In lobsters and crabs two such chambers are found under -the flaps of the carapace, above the walking-legs. Gills are divided -so as to present much surface to the water, from which they absorb -oxygen. They are like a dense mass of little tubes arranged along a -central tube. The class has two kinds of eyes, simple and compound; -the latter are composed of a number of eyes. In some species the eyes -are placed on the ends of movable stalks, which enable the creature -to see in all directions and from a higher plane than the body -occupies. As a rule, the eyes occur in the head region, but in the -shrimp /Euphausia/ they are on the thorax and abdomen. In barnacles -simple eyes exist in the young stage, but in adult forms there are -no apparent visual organs. The ear (so called) consists of a sac -containing small silicious particles suspended in fluid. Numerous -fine hairs on the inner surface of the sac connect with nerve-fibrils. - -The organs of hearing are in various places. In decapods, or the -larger /Crustacea/, they are at the base of the antennules. [pg248] - -The muscles are white bundles of fibers, and are in strips, which is -an indication of power and activity. There are four important sets: -twisted ventral muscles which bend the tail and are particularly -large and strong, those which straighten the tail, those moving the -appendages, and those which work the gastric mill. - -[Illustration: Zoea of /Cancer irroratus/. Last stage before it -changes to the megalops condition.] - -The eggs, after being discharged, are attached to the abdominal legs -of the mother by a kind of cement, or they are carried in pouches -attached to the thorax. In these positions they mature, and hatch at -different stages of development in different species. Some emerge -with three pairs of legs, and are known as /Nauplius/; some are -/Zoea/, having a carapace and abdominal segments, but no abdominal -appendages. Another stage is /Megalops/, with large stalked eyes. -Others are hatched as miniature adults. These names were given when -the embryo stage was not recognized and the larvae were thought to be -distinct species. - -[Illustration: Megalops stage of /Cancer irroratus/, just after -change from zoea stage.] - -The growth of the animal is effected by moulting. The /Crustacea/ -are named from the crust-like covering which envelops them. It is -a horny material, called chitin, in which are deposited particles -of carbonate of lime, making a rigid envelop which would prevent -all freedom of motion, were it not that there are spaces free from -lime, and thus flexible joints are left. When the animal expands it -throws off this hard covering and secretes a new and larger one. As -the time of moulting approaches, the old covering becomes loosened, -and a delicate new one is formed beneath it. The old shell splits -open across the back just behind the carapace, and the soft animal -withdraws first its cephalothorax and then its abdomen, leaving the -cover complete, including even the covering of the eyes and the -lining of the stomach. The [pg249] new shell is rapidly hardened, -being already formed when the old one is cast, and the animal -regains its normal condition in about a week; in the meantime it -is defenseless, and lies quiet in some secluded place. Moulting is -an exhausting process, and is attended with great dangers. A great -mortality occurs at this time from accidents, from weakness, and also -from helplessness in case of attack. - -The hair-like processes scattered over the shell, often like fringes, -are said to be organs of feeling. - - - - -SUBCLASS =ENTOMOSTRACA= - - -These are /Crustacea/ of small, often microscopic size, of -comparatively simple organization, and with appendages adapted -to serve the purpose of respiration. These minute animals may be -obtained by skimming the surface of the water with a muslin net, -preferably at night, then washing off the inside of the net with a -small quantity of water into a glass dish. Place the dish on a dark -surface before a light, and the little creatures will gather toward -the light, and may be satisfactorily observed with a glass. - - -ORDER =COPEPODA= - -This order, though composed of minute forms, is one of great economic -importance, from the fact that the little crustaceans exist in -vast numbers and furnish a very considerable part of the food of -many fishes. ^Cyclops^ is the most common of the fresh-water, and -^Cetochilus^ of the marine genera. These, together with other genera, -swarm in water wherever life exists, from the smallest pools and -ditches to the broad surface of the ocean. Without having drawn -a surface-net on some sheltered bay, it is difficult to have an -idea of the myriads of /Entomostraca/ in the sea. Although nearly -transparent and of such delicate texture as to be almost jelly-like, -they sometimes color the sea with a reddish tint for miles. Whales -which have baleen, or fringes of whalebone, in the mouth subsist -on these small organisms, which are called "brit" by the whalemen. -The whales, sometimes in schools, rush through the water with open -mouths, engulfing these little [pg250] crustaceans, the baleen -straining them from the water. Although devoured in such immense -quantities, and sometimes lying dead in sheets of scum on the surface -of the water, they maintain their numbers by the exceeding rapidity -with which they reproduce. It has been computed that the descendants -of one /Cyclops/ may number in one year 4,500,000,000, provided all -the young reach maturity and produce a full number of offspring. - -One of the free marine forms, ^Sapphirina^, is of especial interest, -as it surpasses all animals in phosphorescence and sparkles by day as -well as by night. It is one quarter of an inch long, and is broad and -flat. - -Besides the myriads of free-swimming copepods, there are parasitic -forms in great number. The marine parasitic forms are commonly known -as fish-lice. They have various habits, some living as commensals, -others attaching themselves to animals only to be carried about; the -true parasites live upon the blood and tissues of their hosts, and -may fasten themselves to the external parts of the body or to the -internal organs. Whales, fishes of all kinds, mollusks, starfishes, -jellyfishes, and corals, all have some form of parasite, and many -have several different kinds of guests. It is said that the haddock -has more than a dozen which infest its external and internal -membranes. - -^Nicothoe^ is found on the gills of lobsters. The truly parasitic -forms are usually very degenerate and lose the characteristics of -their order. - - -ORDER =CIRRIPEDIA= - -("/Curled feet/") - -THE BARNACLES - -Barnacles of the genus /Balanus/ (acorn-shells) (Plate LIX.) are -familiar objects on rocky shores, which they often whiten with their -shells, and those of the genus /Lepas/ are also widely known. The -name of the order is descriptive of their curled appendages. The -appendages are fringed like feathers and are drawn into or protruded -from the shell at will. When extended they are constantly in motion, -and create currents which carry food to the [pg251] mouth of the -animal, which is dependent upon such food as comes within range of -its tentacles. - -[Illustration: /Balanus./ A, external view: /s/, scutum; /t/, tergum.] - -[Illustration: /Balanus./ B, anatomy: /a/, antennules; /ad/, adductor -muscle; /m/, muscles of scuta and terga; /o/, edge of parapet; /ov/, -ovary; /ovi/, oviduct; /sc/, scutum; /sk/, parapet; /t/, tergum; -/wo/, female aperture.] - -Their life-history is interesting. The young barnacle, called a -/nauplius/, in no way resembles the adult. When it emerges from the -egg it is a free and independent animal, with one eye, three pairs -of legs, and a single shell. It swims about for a while and moults -several times. It then has two eyes, two shells, and six pairs of -legs. At this period it seeks a permanent home, and attaches its -anterior end to the object it selects by means of its antennae, -which have become suckers. It makes its hold secure by secreting a -cement which permanently fastens it to the spot. It then undergoes -metamorphosis, loses its bivalve shell and its eyes, and attains its -characteristic /cirripeds/, or curled feathery legs, and a new shell -covering. During these transformations, from the time it becomes -fixed until it attains its adult form, the barnacle fasts, living by -the absorption of its own animal fat. Its food subsequently consists -of the minute animal forms which abound in the sea. Its further -growth is by moulting, but parts only of its covering are disengaged; -the shell is permanent, and its successive stages of growth are -marked upon it by lines, as in mollusks. The lining of the shell, or -enveloping skin of the animal, and also the cuticle of the legs are -[pg252] shed, and in the spring of the year these thin, glossy casts -are found in abundance floating on the surface of the water near the -shore. - -There are but three orders of barnacles, namely, those in which the -shell is directly attached to the rocks, those which are attached to -floating objects by a long stalk, and those which are parasitic on -animals. A species of the third order infests the whale. - -The older zooelogists classed barnacles with the /Mollusca/, but in -1829 Vaughan Thompson, in the study of their embryology, found that -they should be classed with crustaceans, in company with crabs, -shrimps, and water-fleas, with which their immature forms show direct -relationship. - - -GENUS ^Lepas^ - -This genus is commonly known as the ship-barnacle, also as the -goose-barnacle. It attaches itself to floating logs as well as to -ships, but the latter form its principal home; consequently it -is a great voyager, and, though common everywhere, is everywhere -considered a stranger. The same species are found on ships coming -from the most remote and widely separated regions, and so they cannot -be considered native to any one locality. They are wanderers on the -deep, and grow in such numbers on the bottoms of ships, especially -of those which sail in warm seas, that they seriously impede the -progress of the vessels. Aside from diminishing its speed, they do a -ship no injury. - -There was a tradition, which lasted several centuries, that geese -were hatched from these shells, which somewhat resemble eggs. Gerard, -in the appendix to his "Herball or Generale Historie of Plants" -(1597), gives a picture of shells of /Lepas/ growing on a tree, with -geese falling from them and swimming about in the water below. His -description is as follows: "There are founde in the North parts of -Scotland and the islands adjacent called Orchades certaine trees -whereon do growe certaine shell fishes of a white color, tending to -russet, wherein are conteined little living creatures; which shells -in time of maturitie do open, and out of them grow those little -living foules whom we call barnakles, in the North of England brant -geise, and in Lancashire tree geise; but [pg253] the other that do -fall upon the land do perish and come to nothing." He then describes -in detail the various transformations, and ends with: "But what our -eies have seen and hands have touched we shall declare." - -The long, flexible stalk of /Lepas/ is its anterior end. Generally -this stalk is only half an inch long, but in some species it attains -the length of a foot. - -Huxley describes the barnacle as a crustacean fixed by its head and -kicking food into its mouth with its legs. The mouth has a pair of -small mandibles and two pairs of maxillae, the last pair uniting to -form a lower lip. The thorax has six pairs of branched appendages. -The body is enveloped in a fold of skin, to which are attached five -shell-like plates. One of these plates is long and narrow, and -extends along the dorsal side; two are large and triangular (the -terga); two are small and triangular (the scuta), the long point -extending downward. These shells are on the free or posterior end. - -Barnacles have a nervous system, consisting of a brain and a chain -of five or more ganglia, but no special respiratory or circulatory -organs are known; the cirripeds, or feet, are supposed to perform -these functions. They have also a food-canal, a digestive gland, and -excretory tubes. The eggs are carried under the external fold of the -skin in flat cakes. - - ^L. anatifera.^ The shell is bluish-white, showing lines of growth - and faint radiating lines emanating from the anterior basal angle. - The upper valves are narrow; the long tips point downward, and - the top is blunted, leaving a space which is occupied only by a - membrane. Near the apex of the shell, at the back, is a distinct - angle. The dorsal valve is broad, not much compressed, and is - sometimes grooved lengthwise. The cartilage of the shell and - the stalk adjoining the shell are orange-colored. The stalk is - grayish-brown and the cirri flesh-colored. The stalk is from one - inch to six inches long. The shell is one inch long. - - ^L. striata.^ Shells bluish-white; valves sharply triangular; - dorsal valve compressed, forming a ridge; lines radiate from the - basal angle of the lower valves and from the upper angle of the - terminal valves, starting from the extreme end; the margins have a - narrow edge of yellow cartilage; the stalk and cirri are of a dark - slate-color; shell and stalk are each about an inch long. - - ^L. pectinata.^ Shell shorter and less compressed than in the - preceding species; lines of growth and radiating lines distinct; a - decided line [pg254] runs from anterior base to summit, a little - back of the margin; terminal end broadly obtuse (truncated); dorsal - valve much compressed, forming a sharp edge serrated with ten to - twelve teeth and distinctly striated or furrowed. - -[Illustration: /Lepas anatifera./ A, the entire animal; B, anatomy. -/a/, antennule; /c/, carina; /cd/, cement-gland; /l/, digestive -gland; /m/, adductor muscle; /od/, oviduct; /ov/, ovary; /p/, -peduncle; /s/, scutum; /t/, tergum and testis; /vd/, vas deferens; -/h/, tentacles.] - -[Illustration: PLATE LIX. Different forms of Balanus. (After Darwin.) -Cenobita diogenes.] - - -GENUS ^Balanus^ - -/Balanus/ is known as the "acorn-shell," or "sea-acorn," and is found -in vast numbers and of all sizes between tide-marks, incrusting rocks -and the piles of piers. It also may be found attached to floating -objects or to shells, or even to living animals, but its usual -habitat is stationary. Unlike /Lepas/, it has no stalk, the shell -being directly attached to some object. The body is surrounded by a -fold of skin, to which are attached a shell consisting of six or more -plates and a fourfold lid, or /operculum/, consisting of two /scuta/ -and two /terga/. The operculum may be called the door, as the animal -opens and shuts it at will and has complete protection when it is -closed. If one taps a rock [pg255] incrusted with barnacles, and -holds the ear near, the closing of the many doors may be distinctly -heard. - -The development of /Balanus/ from the larval stage, as also the -anatomy of the adult, is similar to that of /Lepas/. When covered -with water and unmolested, there may be seen over a bed of barnacles -thousands of tiny fringed feet waving to and fro. The motions look -like gestures; they are perfectly regular and rapid, numbering -eighty to a hundred a minute. The shell covering formed by barnacles -on piles of wharves and bridges is said to be a protective agent; -otherwise the barnacles seem to have no economic value in nature, -as, unlike other animals, they do not serve, except in very small -measure, as food to other classes. The tautog and perhaps some other -fishes feed partly upon them. They are sometimes an obstacle to -oyster-culture, as they fasten upon the objects intended for oyster -embryos, and, growing faster than the latter, soon crowd them off. -One species, /Coronula diadema/, fastens to the skin of whales. It -attains the size of two inches in diameter. The shell is half an -inch thick and full of cavities, into which the skin of the whale is -drawn, giving the barnacle a secure hold. (Plate LIX.) - - ^B. balanoides^ (Stimp.), ^B. ovularis^ (Gould), the rock-barnacle. - This is perhaps the most conspicuous of the barnacles. It inhabits - the whole northern Atlantic coast, and is so abundant that it not - only whitens the rocks with a complete incrustation of shells, but - the animals are so crowded that many of them lose their normal - shapes and become greatly elongated. When the rocks are covered - with water they seem alive, on account of the thousands of waving - tentacles. This species also incrusts woodwork between tide-marks. - - The shell is small, white, and variable in shape; sometimes its - height is less than the diameter of its base; again the height is - several times greater and the summit broader than the base. In its - early stages the valves are smooth, but later the base is scalloped - by four or five grooves. The summit of the plates is even and - blunt. The aperture is diamond-shaped. Two valves of the operculum - are pointed at the tips; two are blunt, making a deep notch in - the summit. These valves are the distinctive feature by which to - recognize this species, which varies so much in outward form; the - species is also distinguished by its membranous base, which does - not form a solid plate like that of other species. - - ^B. eburneus^, the ivory barnacle. This species, like /B. - balanoides/, is a very common barnacle, and is found on all kinds - of submerged woodwork, whether fixed or floating. It is also found - on the carapace of [pg256] crabs and /Limulus/, and on mollusks. - It is chiefly found on objects below low-water mark. It ranges - from Massachusetts Bay to Florida. It is easily distinguished from - the preceding by its low, broad form and shelly base. The shell is - smooth and circular at the base, and inclines backward, forming an - oblique cone with a triangular opening; the plates terminate in - points at the summit and incline backward, the last one forming a - kind of beak. The operculum is pyramidal; two of its valves have - both transverse and longitudinal lines well defined at the base, - and are coarsely toothed at the edges; the posterior valves are - slightly grooved across. - - ^B. rugosus^ (Gould), ^B. crenatus^. Shell white, cylindrical, - somewhat conical, rugged, the summit usually as broad as the base; - height often greater than diameter; aperture diamond-shaped, plates - ending at the summit in acute spreading points, the posterior plate - folded and curved like a beak; plates rough, with coarse, irregular - ribs; valves of the operculum at the summit acute, with diverging - points; the points striated. Found on shells and stones in deep - water and also on bottoms of ships. - - ^B. geniculatus.^ Shell dirty greenish-white, cone-shaped; aperture - about the size of base; shell-plates triangular, unequal in - breadth, and with alternate large and small ribs; the smaller ribs - compressed and roughened on the edges by the conspicuous lines of - growth which run across them; depressed areas between the plates - marked with fine cross-lines; front valves of the operculum have - coarse plated ridges, which incline over one another and are - crossed by fine radiating lines; diameter at base one to one and - a half inches; height two thirds the diameter. Found on pecten - shells, and abundant off the coast of Maine. - - ^B. tintinnabulum.^ Shell pink to purplish, conical, with six - triangular plates, which are grooved, forming unequal ribs, and - crossed by distinct lines of growth; spaces between plates crossed - by lateral lines; posterior valves of the operculum longer than the - others and curved forward, resembling the beak of a bird of prey; - diameter at the base one inch; height one and a half inches. Found - in warm waters and on vessels from the South. - - -SUBORDER ~RHIZOCEPHALA~ - -These are parasitic forms and very degenerate. ^Sacculina^ lives on -crabs, and its term of life is about three years, during which period -the afflicted crab does not moult. Its shape is that of an ovoid sac -on a stalk, which it attaches between two segments of the ventral -surface of its host. The stalk divides and ramifies in a root-like -manner within the body of the crab, from whose vital elements it -absorbs its nourishment. The roots spread like a mycelium through the -whole crab, even to the claws. - -^Peltogaster^ lives on hermit-crabs. [pg257] - - -SUBCLASS =MALACOSTRACA= - -This subclass comprises highly organized /Crustacea/, usually of -considerable size, having the appendages much differentiated, the -thorax with eight segments, and the abdomen with seven segments. - - -ORDER =SCHIZOPODA= - -The name, meaning "cleft-footed," applies to the appendages of the -thorax, which are once-branched (/biramous/). Gills, when present, -are attached to these feet, and hang freely in the water. A delicate -carapace covers the thorax; the abdomen is proportionately very -large, often twice the length of the cephalothorax. In /Mysis/ the -eggs are carried in pouches under the thorax, giving the common -name of "opossum-shrimp" to this small, transparent, phosphorescent -crustacean. - -[Illustration: /Mysis sternolepis./] - - -GENUS ^Mysis^ - - ^M. sternolepis.^ About one inch in length; translucent; antennae - very long; segments marked at joints with dark spots; the last two - segments terminate in a stout spine; telson longer than the sixth - segment; the sides are nearly straight and are armed with spines; - the extremity is cleft; eyes large and prominent. Found abundantly - in winter on the shores of still, muddy bays and sounds, especially - among eel-grass. - - -ORDER =DECAPODA= - -("/Ten-footed/") - -The /Decapoda/ are named from their ten walking-legs. The higher -forms of crustaceans belong to this order. All the /Decapoda/ -have a similar anatomy, but are placed in two subdivisions -[pg258] according to their external form. In /Macrura/, the first -subdivision, belong the lobsters, crawfish, shrimps, prawns, and -hermit-crabs, animals having a long and more or less cylindrical -body, with the abdomen extended; in /Brachyura/, the second -subdivision, are placed the crabs, animals having the thorax broad -and flat, and the abdomen bent under the thorax. The /Decapoda/ -have twenty segments, all of which, except the last one, have, at -some period of life, a pair of appendages. The first two pairs of -appendages, or, in the stalk-eyed forms, the first three pairs, -are especially connected with the senses, and are often fringed -with hairs, which are also considered to have a sense-function. The -/antennules/, or first pair of appendages after the eye-stalks, are -sometimes divided into two or three branches. At the base of the -antennules are the ears. The /antennae/, or second pair of appendages, -are undivided, but are larger than the first pair, and are often -very long. At the base of the antennae are the renal glands. Both -the antennules and the antennae are slender, elongated, movable, and -full of joints. In some species they are greatly modified, as in -/Scyllarus/, where they are developed into broad swimming-plates and, -perhaps, as shovels for burrowing; in some amphipods they are used as -swimming-organs. (Plate LX.) - -[Illustration: PLATE LX. External Anatomy of a Lobster. /C/, -carapace; /e/, eye; /g/, gill; /m/, metastoma; /n/, endopodite; /p/, -epipodite; /x/, exopodite; I-VII, abdominal segments; 1, antennula; -2, antenna; 3, mandibles; 4, 5, maxillae; 6, 7, 8, maxillipeds; 9, big -pincer; 10-13, walking-feet.] - -The next six pairs of appendages are grouped about the mouth. They -are the /mandibles/, the /maxillae/, and the /maxillipeds/. The -mandibles are at the mouth-opening, and, being heavy and hard, are -adapted to tearing and grinding; they have a jointed attachment, -the /palpus/, whose office is to keep the mandibles clean. The two -pairs of maxillae are delicate and leaf-like. The three pairs of -maxillipeds grow gradually larger, the last pair being very prominent -and extending over the other mouth-parts. Next come five pairs of -walking-feet. One or more pairs of these feet have pincer-like ends, -or claws. Some species have the claws immensely developed, as in -lobsters. The claws are the /chelae/, and the feet which bear the -/chelae/ are termed the /chelipeds/. The rest of the walking-feet -have generally single, hook-like ends, but are variously modified -in different species. The abdominal segments have six pairs of -appendages, also variously modified. The last segment is without -appendages, but often is extended into a tail, [pg259] or -fin-like expansion. The next to the last segment, in many forms, has -appendages modified into swimming-plates, which extend on each side -of the telson, forming a broad, fan-like caudal extremity. - -They have, then, to correspond to the twenty segments of the body, -two pairs of sensory, six pairs of mouth-, and five pairs of -walking-appendages attached to the cephalothorax, and six pairs on -the abdomen. The terminal segment, or telson, is without appendages. -The exopodite is present on the maxillipeds, but disappears from the -walking-feet in the higher forms. - -In moulting the /Macrura/ split in the longitudinal line down the -back; in the /Brachyura/ the split occurs across the body at the -point between the thorax and the abdomen. - - -SUBORDER ~MACRURA~ - -SHRIMPS, PRAWNS, LOBSTERS, CRAWFISH, AND HERMIT-CRABS - -The characteristic features of the /Macrura/ are an elongated body -with the abdomen usually extended; a carapace, somewhat cylindrical; -and the last pair of appendages of the abdomen (which are attached to -the next to last segment) united with the last segment, or telson, to -form a powerful caudal fin, used for swimming backward. The creeping -forms in moving walk forward, but swim backward. - -FREE-SWIMMING FORMS: SHRIMPS AND PRAWNS - -In these animals the body is compressed and the carapace is not hard. -The abdomen is very large in proportion to the cephalothorax, and has -a peculiar bend. The rostrum is often longer than the thorax. The -eye-stalks, antennae, and legs sometimes attain extraordinary length, -and the chelae (claws) are not always on the first pair of legs. In -some species chelae are on two or three pairs of the legs. Above the -antennae are expanded antennal scales, which, together with the long -bases of the antennules and very prominent eye-stalks, make the head -a broad and conspicuous feature. The difference between shrimps and -prawns is not very well defined, the small individuals seeming to -be generally called shrimps, the larger full-grown ones prawns. -[pg260] Prawns are known as /crevettes/ in France and as /Garnelen/ -in Germany, where they are largely used as food. In the United States -the shrimp-fishery is an industry of the South. On the California -coast the fisheries are very extensive and are monopolized by the -Chinese. - - -GENUS ^Penaeus^ - - ^P. setiferus.^ This species is about six inches in length when - full-grown. A ridge or crest extends along the center of the - carapace, and terminates in a long, pointed, toothed rostrum, - the teeth being fringed with hair on the inner side. The antennae - are a foot or more in length; there are chelae on the first three - pairs of thoracic feet; the swimming-feet and lateral margins of - the segments of the abdomen are fringed with hair; and the caudal - appendages are longer than the telson. It ranges from Virginia - southward, and is very abundant on the shores of the Southern - States, where it is gathered for the markets. The large ones are - known as prawns and the small ones as shrimps. - - ^P. brasiliensis.^ This species is associated with /P. setiferus/, - and, although not so abundant, forms a part of the shrimp-supply - in the fisheries. It differs from the former in having a groove - on each side of the ridge which runs through the center and whole - length of the carapace. The first three pairs of feet are chelated. - This shrimp is found as far north as Long Island, and often in - brackish water, or even where the water is quite fresh. - - -GENUS =Palaemonetes= - - ^P. vulgaris (Palaemon vulgaris).^ Average size one half of an inch - in length; body translucent, almost colorless, irregularly spotted; - rostrum as long as carapace and toothed on the upper edge. It is - found among eel-grass in brackish water, and also in pools and - ditches on muddy shores from Massachusetts Bay to Florida. Commonly - known as prawns. - -[Illustration: /Palaemonetes vulgaris/; male.] - - -GENUS ^Crangon^ - - ^C. vulgaris^, the common sand-shrimp. It ranges from Labrador to - North Carolina on the Atlantic coast and from Alaska to southern - California on the Pacific coast. It is found in abundance on sandy - shores at low-water mark, and in shallow water below tide-mark; - also among rocks and seaweeds. When left by the tide it buries - itself in the sand. Its color varies with its location, rendering - it inconspicuous. Upon the [pg261] sandy shores it is translucent, - pale in color, and often specked, closely resembling the sand, - while on dark, muddy bottoms it is much darker. This is an edible - shrimp, eagerly devoured by fishes; it is also gathered for the - markets. The body of /C. vulgaris/ is broad at the anterior end - and tapers to a sharp point at the posterior extremity. A pair of - broad, divided appendages on the cylindrical segment, which is next - to the last on the abdomen, together with the sharp telson, form a - fan-like swimming-tail. As in all shrimps, the antennae are long and - have plate-like antennal scales at the base, which are fringed with - hairs. The mandibles are long. The movable finger of the chela is - folded across the extremity of the claw. - - ^C. franciscorum^, the California shrimp. This species is about - three inches in length. It is distinguished from /C. vulgaris/ by - its larger size and by the greater length of the movable finger of - the chela, which folds parallel to the side of the claw instead of - across its extremity. Its color is light or dark yellowish-gray, - mottled. This is the shrimp extensively gathered by the Chinese for - commercial purposes. The shrimp-meat is dried and cured, and then - separated by blowers very much as wheat is cleaned. It is exported - to Eastern countries in great quantities, the value of the export - being estimated at one hundred thousand dollars per annum. - -[Illustration: /Crangon vulgaris/, the common sand-shrimp; male, -natural size.] - - -CREEPING FORMS: LOBSTERS AND CRAWFISH - - -FAMILY ~ASTACOIDAE~ - - -GENUS ^Homarus^ - -There are but three species of this genus, which is the most -important one of all the /Crustacea/. They are /H. vulgaris/ of -Europe, /H. capensis/ of the Cape of Good Hope, and /H. americanus/, -which occurs on the eastern coast of the United States from Labrador -to New Jersey. The lobster-fishery is one of great importance, and of -such value that it is governed by stringent laws. The [pg262] annual -catch on the Atlantic coast of North America amounts to many millions -of lobsters, the money value of which is very large. - - ^H. americanus^, the common lobster of the Atlantic coast. - The characteristic feature of the lobster is its enormously - developed chelae, or pincer-claws, which are on the first pair of - walking-feet. Small claws occur on the next two pairs, and simple - hooks on the remaining two pairs. The appendages on the abdomen are - divided (biramous). In the female they are used, excepting the last - pair, for holding the eggs; in the male they are greatly abridged. - The appendages on the next to last segment are divided and broadly - flattened, forming with the telson a powerful swimming-paddle. The - rostrum is very prominent, and has a long, pointed end, slightly - upturned, and several spines. - - The lobster belongs to the creeping forms of the order; it walks - forward by means of the ten feet, but swims backward by using its - caudal fin. It lives in deep water on rocky bottoms, hiding among - stones, etc., but frequents sandy shores as well. It lives on - dead and decaying animal matter, and it would seem strange that - its flesh is so palatable, were it not that we know that chemical - combinations which take place in the assimilation of food make one - kind as clean, when transformed, as another. All the crustaceans - have a similar dietary, being scavengers of the sea; yet fishes - find them more acceptable than other animal food, and fishes - capable of capturing larger prey subsist largely on the minute - entomostracans described elsewhere. - - [Illustration: /Homarus americanus/, American lobster; male.] - - The lobster is so large that it can easily be dissected, and will - serve as a type of the structure of /Crustacea/. In dissecting one - can follow the descriptions given of the anatomy of /Crustacea/ - on page 246, and will be interested in observing the beautiful - arrangement of the parts and their adaptation to the uses they - serve. [pg263] - - The female lobster carries her eggs on the abdominal legs, to which - they are glued by a kind of cement. After the young emerge from - the egg, the zoeae still cling to the mother for a little time. - The lobster moults eight times the first year, five times the - second, and three times the third year, after which the male moults - twice and the female once a year. It retires to some secluded - spot for this operation, which is attended with many dangers. The - back splits open longitudinally and the animal slowly withdraws, - leaving the shell complete. In preparation for moulting, the lime - around the contracted joints of the chelae is absorbed, so that the - soft flesh can pass through. Any injury to a limb at the time of - moulting, or which results from fighting or from any accident, is - repaired at successive moultings, and a lost member is replaced by - a new, but not always a perfect, one. - - -GENUS ^Panulirus^ - - ^P. interruptus.^ This is the California spiny lobster, - rock-lobster, or salt-water crawfish. It differs from the common - lobster /Homarus/ of the Atlantic coast in having no large claws, - the first pair of feet being simple like the rest, also in having - antennae which are enormously long and very large at the base. The - carapace is beset with spines, and the lateral margins of the - abdominal segments end in spines. This species lives among the - rocks on the southern California coast. - - [Illustration: /Panulirus interruptus/, the spiny or rock-lobster.] - - ^P. argus^ or ^americanus^ resembles /P. interruptus/, and is found - on the coast of Florida. - - -GENUS ^Scyllarus^ - -/Scyllarus/ has a broad, almost square carapace, which is uneven and -coarsely granulated; the anterior corners are sharp, the posterior -ones rounded. The antennae are curiously modified into broad, flat, -double plates reaching quite across the straight anterior end of the -carapace. The under scales of these modified antennae are rounded and -leaf-like, the upper ones are pointed. The margins of the abdominal -plates on the ventral side are toothed, and on the upper side the -first three sections have [pg264] knobs, the third one being the -most prominent, and forming the posterior extremity when the abdomen -is folded in. The walking-feet are all simple and end in points; -the first pair are the longest, and the following ones gradually -diminish in size. The ventral surface is rough and spiny. The abdomen -is of about the same length as the carapace. These animals are found -off the Florida coast and are caught in the fish-traps. They are -uncommon. The very peculiar development of the antennae makes them -worthy of examination when opportunity offers. - - -ANOMALOUS FORMS: ANOMURA - -The anomalous forms which are intermediate between the suborders -/Macrura/ and /Brachyura/ were, until recently, placed in a suborder, -/Anomura/. The members of this group differ from one another, and -some of them resemble in external features members of the other -divisions of the suborders, but there is a difference in anatomical -structure which separates them in the classification. - - -FAMILY ~DROMIDAE~ - - -GENUS ^Hippoconcha^ - - ^H. arcuata.^ This curious little crab, found on the Florida coast, - carries the half of a bivalve shell over its back. Its fifth pair - of thoracic legs are bent over the back, and these, together with - the fourth pair of legs and the spiny front edge of the carapace, - enable the crab to hold the shell in position. This crab was - formerly classed with the hermits, all of which were originally - called /Bernhardus/, after the monk of that name. - - -FAMILY ~PAGURIDAE~ - -THE HERMIT-CRABS - -In these curious animals the posterior part of the body is not -protected by a crustaceous covering, and therefore the animal seeks -protection by inserting its soft and defenseless abdomen into some -hollow object, usually the shell of a gasteropod mollusk, as the -whelk or the periwinkle (/Buccinum/, /Littorina/). The hermit-crabs -do not always use a shell for this purpose, as they are sometimes -found in the tubes of plant-stems or in sponges. Like other -organisms in the animal world, they seem [pg265] well fitted to -make the best of their surroundings, the body becoming modified to -suit the peculiar conditions under which they live. In those which -inhabit shells the abdomen becomes spiral, in conformity to the -convolutions of the shell. All the abdominal appendages are more or -less atrophied; the sixth pair become like hooks, and these fasten -to the columella of the shell, keeping the crab securely attached -to it. In the female some of the abdominal appendages are hair-like -and are adapted to carrying the eggs. The thorax, being protected, -is protruded from the shell at will. The first pair of feet are much -larger than the others, and are provided with claws (chelae). The -first right foot is usually much larger than the left, and, besides -the usual functions of capturing and crushing prey, the claw, or -hand, serves as an operculum to close the mouth of the shell when the -crab retires completely within it. The small left hand is shaped to -fill out the parts of the opening not covered by the right one, thus -making a close fit. The next two pairs of feet end in simple hooks, -and are used for walking and dragging the crab along when he travels. -These crabs move about very fast, and the houses upon their backs -seem no encumbrance. [pg266] - -[Illustration: /Pagurus bernhardus/: /ch/, chela of first right leg; -/l./4, /l./5, fourth and fifth legs; /t/, abdominal terga; /up/, last -pair of appendages, modified to fasten to the columella of the shell -in which the hermit lives.] - -In some genera both hands are alike; in others the left one is the -larger. In the case of hermits which live in tooth-shells, the -right hand is cylindrical in form, fitting the circular opening of -the shell. The other extreme is found in the genus /Cancellus/, -where both the chelipeds and the first pair of ambulatory feet are -ingeniously shaped, so that when closed they form a round operculum, -or door, which closes the way into the compact sponge which this crab -has for its carcin[oe]cium, or house. It is interesting to note these -differences and observe the perfection with which the feet are formed -and jointed to suit the openings of different shells. Some genera -show other adaptations to their twisted houses, the eye-stalks being -uneven in length and the ambulatory feet unequal on the opposite -sides. Besides this, some species are hairy and cover themselves with -dirt for further protection. The exposed claws of some hermits have a -special armature of spines, which make a fringe of points around the -opening of the shell when the crab is withdrawn. - -As the hermit grows he is occasionally obliged to find a new or -larger shell, and there are amusing anecdotes of the troubles he -experiences at these times while house-hunting. Very often he tries -several shells before he finds one to fit. There is a tradition, -not, however, well authenticated, that if the shell chosen happens -to be occupied by its natural owner, the crab tears out and devours -the unfortunate occupant. If the desired shell is occupied by -another hermit inferior in strength to himself, he proceeds to take -possession by violence. He then examines carefully the empty shell, -inserting his legs and feelers, and if he decides to occupy it he -withdraws his abdomen from the old shell and darts it so quickly into -the new one that the act of transference is difficult to follow. -After walking about with the new shell it sometimes proves to be -unsatisfactory and further search becomes necessary. After it is -well domiciled the crab never ventures outside the shell until it -is obliged to change again on account of growth, or because some -stronger crab dispossesses him. The shells of hermit-crabs serve -frequently as the home of other animals which live with them a -commensal life. The hydroid /Hydractinia polyclina/ often covers -the exterior of such shells with a brown, velvety growth. Some -sea-anemones also are commensals [pg267] with hermits. /Adamsia -palliata/ is always found on the shell occupied by /Eupagurus -prideaux/, and never on any other. This is a European form. On -our own coast a red anemone, the /Epizoanthus americanus/, found -in deep water off the entire eastern shore, fastens on the shell -occupied by the hermits /Eupagurus pubescens/ and /E. kroyeri/. This -anemone in time absorbs the shell of its host and itself becomes its -protector--an advantage to the hermit, who finds room in the yielding -polyp-mass for its increasing size, and feels no longer the necessity -for change of domicile. The female hermit holds its eggs in the -posterior feet until they are hatched; the young are then released, -pass into the water, and soon find shells for themselves. - -[Illustration: A colony of sea-anemones (/Epizoanthus americanus/) -which had completely covered and absorbed a shell occupied by a -hermit-crab (/Eupagurus pubescens/), which still lived within the -cavity. The polyps are not expanded.] - - -GENUS ^Pagurus^ - - ^P. bernhardus.^ This is a large species, bright red in color, - rough and hairy. It inhabits the shells of /Fulgur carica/ or - of /Polynices heros/. It ranges from Cape Cod northward, and is - replaced on the northern California coast by /P. alaskensis/ and - /P. aleuticus/. - -[Illustration: /Pagurus bernhardus/, the hermit-crab.] - - ^P. pollicaris.^ This hermit inhabits shells similar to those - occupied by the last, but is pale red in color, and its surface - is granulated and not hairy. The short joint of the chela has a - broad angle. It ranges from Massachusetts to Florida, and occurs at - low-water mark on rocky and shelly bottoms of bays and sounds. - - ^P. longicarpus.^ A quick-moving little hermit with long chelipeds, - found in small shells at the water's edge in quiet places. They - exist in great numbers and are eaten, shell and all, by fish. This - species can be distinguished from all others by its very light - color and metallic luster. - - -GENUS ^Clibanarius^ - - ^C. vittatus.^ This hermit is found from North Carolina southward - along the edge of the water and in tide-pools. It cannot be - mistaken [pg268] for any other hermit common on our coast, since - it has the very distinctive feature of white longitudinal stripes - on the ambulatory feet. The chelipeds are about equal, rough with - tubercles, and the tips have smooth black edges. Body and feet are - quite hairy. The color is brown and white. - - -GENUS ^Pylopagurus^ - -This genus is represented in Southern waters by several species. -One of the most characteristic of them lives in /Dentalium/, the -tooth-shell. The outer surface of the right hand is formed to close -the shell. All the ambulatory feet and the very small left hand fold -beneath, leaving only the flat surface of one hand exposed to view. -Another species lives in a shell covered with polyzoans. - - -FAMILY ~CENOBITIDAE~ - - -GENUS ^Cenobita^ - - ^C. diogenes.^ This large hermit-crab, found in Florida and in more - southern waters, inhabits the beautiful pearly shell of /Livona - pica/. It lives on land a part of the year, but spends the breeding - season in the water. It can be distinguished by its land-roaming - habits, its large left cheliped, very stout walking-legs, and - compressed eye-stalks. This species climbs the hills, but is more - frequently met with in low, shaded, marshy places. (Plate LIX.) - - -FAMILY ~HIPPIDAE~ - - -GENUS ^Hippa^ - -[Illustration: /Hippa talpoida/, the sand-bug.] - - ^H. talpoida.^ This animal, commonly known as the "sand-bug," - differs greatly in appearance from a crab. When the appendages are - folded under the carapace it somewhat resembles an egg, the body - being ovate, about half as broad as long, and the sides forming a - nearly regular curve. The carapace is about one and a half inches - long, convex, yellowish-white, and nearly smooth. The abdomen is - long and pressed under the body, reaching nearly to the front. - The eyes are minute and on the ends of long, slender stalks. The - antennae are plume-like and about as long as the carapace. /Hippa/ - lives on sandy beaches at or near low-water mark, exposed to the - action of the waves. It burrows with great rapidity into the loose - and shifting sands, using the short and stout second, third, and - fourth thoracic legs and the appendages of the sixth abdominal - segment [pg269] for pushing and digging. Crabs of this species - are gregarious and may be seen in great numbers, though but few - will be captured together by digging, as they rapidly disappear - beneath the sand. Sometimes they are found swimming about in the - tide-pools. They seem to live upon the organic particles contained - in the sand, which they swallow, the mouth not being adapted for - mastication. This species ranges from Cape Cod to Florida. (Plate - LXI.) - - ^H. analoga.^ Similar to /H. talpoida/, but broader and flatter. It - is bluish above, yellowish-white below, and the fringing hairs are - black. Found on the California coast. - - -GENUS ^Albunaea^ - - ^A. gibbesii.^ This animal is found with /Hippa/, and, like it, - burrows rapidly in the sand. Its general outline is square. The - surface of the carapace is marked off with denticulated lines, - which make the back appear as if composed of plates. The front edge - of the carapace has a row of teeth and a prominent spine at the - anterior angles. The abdomen is doubled under itself (not fitting - into a groove of the thorax, as in ordinary crabs), this animal - being intermediate between the long- and the short-tailed forms. - The eyes are on triangular, plate-like stalks. The antennules are - very long and are fringed with hair. The chelipeds have claw-like - joints, which close across the straight, broad end of the hand. - The first two pairs of walking-feet have curious sickle-like - terminal joints. The animal is about one and a quarter inches long. - /Albunaea/ does not extend as far north as /Hippa/, its range being - from Georgia southward. (Plate LXI.) - - -FAMILY ~PORCELLANIDAE~ - -The crabs of this family are little more than one quarter to one half -of an inch across the back. The chelipeds are broad and flattened. -The first three pairs of walking-legs are well developed, and the -fifth pair are very small and are doubled over the base of the -carapace. The sixth segment of the abdomen has a pair of biramous -appendages, which, with the telson, form a swimming-fan. - - -GENUS ^Porcellana^ - - ^P. sayana.^ Carapace little longer than broad; breadth about one - quarter of an inch; smooth; has three acute denticulations between - the eyes, the middle one the largest and depressed in the center; - two denticulations on each anterior side; chelae fringed with hair - on the edges; walking-legs somewhat hairy; fifth pair of legs - folded over base of carapace; color reddish, with white spots. - This species was once called /occulata/, because of the eye-like - spots over its entire surface. The posterior part and abdomen have - longitudinal bands of color. The claws are marked like the shell. - Found from South Carolina southward, often in the shells inhabited - by hermit-crabs. (Plate LXI.) [pg270] - - -GENUS ^Petrolisthes^ - - ^P. sexspinosus.^ Carapace longer than broad; breadth about one - half of an inch; space between the eyes broad, but not divided into - three teeth as in /Porcellana sayana/; second joint of the cheliped - has five broad teeth on its front edge and five or six small - spines on its outer edge; fifth pair of legs doubled over base of - carapace; whole body traversed with broken red lines. Found from - South Carolina southward. (Plate LXI.) - - ^P. armatus.^ Carapace longer than broad; breadth about one - quarter of an inch; prominent and wide between the eyes; a small - sharp spine on each anterior side; chelipeds long; second joint - of cheliped twice as long as broad, with three teeth on the front - edge and four or five small spines on the outer edge. Found on the - Florida coast. (Plate LXI.) - - -FAMILY ~LITHODIDAE~ - -The species of this family have a broad, ovate, uneven body and -a prominent rostrum. The fifth pair of legs are rudimentary and -are folded under the carapace in the branchial chambers, so that -the crabs appear to have but four legs on each side. This is -the distinguishing feature of the family, and makes them easily -recognized. - - -GENUS ^Lithodes^ - - ^L. maia.^ The carapace is cordate (heart-shaped), and longer than - broad, exclusive of the rostrum. The margin is recurved all around, - and is beset with numerous very long spines. Six spines on each - anterior side margin are regular and longer than the others. The - surface of the carapace is covered with tubercles and spines and - elevated in places. The rostrum is spiny, a third as long as the - carapace, and has two spines at the base, one above the other, - a spine at each side, two lateral spines near the middle, and - two terminal divergent spines. The chelipeds are unequal and are - covered with spines, those on the inner margin being the longer. - The color is yellowish-red, lighter underneath; the spines are - darker. Found on the fishing-banks off the coast of Maine. (Plate - LXI.) - -[Illustration: PLATE LXI. 1, Hippa talpoida. 2, Albunaea gibbesii. -3. 1, Porcellana sayana; 2, Petrolisthes armatus; 3, Petrolisthes -sexspinosus. 4, Lithodes maia.] - -[Illustration: Plate LXII. Echidnocerus cibarius. Cryptolithodes -sitchensis. Echidnocerus foriminatus. Phyllolithodes papillosus.] - - -GENUS ^Echidnocerus^ - - ^E. cibarius.^ This curious crab has the carapace raised in front - into a large cone-like elevation terminating in a long point. Three - prominent but smaller cones extend across the center of the back, - and two still smaller ones occur on the posterior sides and in the - middle of the posterior margin. The whole surface of the carapace - is covered with coarse granulations arranged in rosette-like - groups. The chelipeds and legs are beset with large tubercles and - fold together in such a manner that when retracted the crab is a - close, compact, box-like mass, with a very rough, [pg271] spiny - armature. The antennae are broad at the base and covered with small - spines on the sides and upper surface, and the eye-stalks are also - spiny. This crab sometimes attains the size of ten inches across - the carapace and a weight of seven pounds, being among the largest - crabs known. It is found at the mouth of the Columbia River and - along the northwest coast. (Plate LXII.) - - ^E. foriminatus.^ This species resembles /E. cibarius/ in the - manner of closing the feet, forming a compact, box-like, spiny - armature. The body is more depressed than that of the latter, - and the cone-like elevations on the back are less prominent. The - spines are hairy. The characteristic feature of this species is a - semicircular cut in the second joints of the chelipeds, directly - opposite to similar depressions in the first walking-legs, so that - when the feet are folded a round hole is left, through which water - flows freely to the gill-openings, which might, without these open - holes, be obstructed by the close folding of the legs against the - carapace. Found off the California coast near San Francisco. (Plate - LXII.) - - -GENUS ^Acantholithodes^ - - ^A. hispidus.^ The whole body in this species, including the legs, - is covered with hairy spines. The abdomen is broad, and covers - about the whole under surface of the body, and is also beset with - hairy spines, but they are less prominent than those on the upper - side. The rostrum, terminating in spines, reaches to the tips of - the eye-stalks, which are also spiny. The chelipeds are larger and - longer than the walking-feet; the latter taper to a point, ending - in a sharp nail. The shape of the body resembles somewhat that of - a toad. This is a deep-water species, but it is sometimes brought - ashore at Monterey, California, by fishermen who find it in the - stomachs of fishes. - - -GENUS ^Cryptolithodes^ - - ^C. sitchensis.^ The most striking characteristic of this singular - species is the great development of the carapace, which forms - a broad, thin shield extending beyond the body and legs, and - completely hiding the animal beneath it. The carapace is smooth - and uneven, has a high ridge through the center of the anterior - part, and the sides are broadly expanded and bluntly pointed at the - extremity. The rostrum appears like a small rectangular piece cut - out of the anterior side of the carapace. This species is found in - the Strait of Fuca. A similar species, /C. typicus/, is found near - low-water mark on the surf-washed rocks of the beach at Monterey, - California. (Plate LXII.) - - -GENUS ^Phyllolithodes^ - - ^P. papillosus.^ The carapace is triangular, about two inches - wide at the base, and narrowing to a long, pointed rostrum which - terminates in a forked spine. The surface of the carapace is deeply - depressed in parts, and forms a heart-shaped figure in the center. - The lateral margins have four prominent spines on each side, the - two at the posterior ends being [pg272] thicker than the other - two. The abdomen is broad, covering the whole under side of the - body, and is marked off with prominent raised ridges diverging from - the center line. The legs are all beset with long, rough spines. - Habitat, the northwest coast. Taken from the stomachs of fishes off - Monterey, California. (Plate LXII.) - - -SUBORDER ~BRACHYURA~ - -THE CRABS - -This group contains the true crabs, which are the highest of the -/Crustacea/. In form they are quite the reverse of the first group. -In the /Macrura/--except in the anomalous forms--the body is long -and cylindrical and the abdomen extended, but in the /Brachyura/ the -body is flat and broad and the abdomen short and reflexed. Crabs of -this suborder inhabit all seas of the globe, and are found from the -shore to great depths. Some species live on land, some on the shore, -some in deep water. Some forms burrow in the sand; others live under -stones and boulders, or conceal themselves in crevices of rocks or -in the cavities of sponges. They are divided into many families, -and creep, climb, swim, or burrow, their structure being modified -to their respective modes of life. There is also great variation in -their shapes as well as in their color and markings. This diversity -is so great and peculiar that it seems as though each one were more -curious than the others. - -In crabs the cephalothorax is depressed and often broader than long. -The abdomen is relatively small and is folded under the thorax, lying -in a groove which it fits so perfectly as to be quite hidden from -above. The appendages of the abdomen are much reduced in number. The -male has two pairs; the female has four pairs, which it uses for -carrying its eggs. The first pair of walking-legs are comparatively -large, and end in chelae, or pinching-claws. The other eight legs -terminate in simple points, except in the swimming varieties, when -the fifth pair is flattened to form fins, or swimming-paddles. The -eye-stalks are long and fit into sockets on the carapace. Both pairs -of feelers are small. The antennules are frequently folded into small -grooves. The external or third pair of maxillipeds are broad and -flat, and cover the mouth-parts like a lid, or operculum. [pg273] - -Crabs, like other crustaceans, are scavengers, living on dead animal -matter; but the land species are also vegetarian in diet. They are -great fighters, but are also wily, often averting danger by resorting -to stratagem. They are an interesting and curious group, as they -possess a good degree of intelligence and have amusing habits. - -From the time they leave the egg until they attain the adult form -they pass through several complete and singular metamorphoses. The -most marked forms are called the /Zoea/ and the /Megalops/. So little -do these resemble the adult that originally they were classed as -distinct genera far removed from the one to which they really belong. -After the larva has moulted several times it appears as in the -illustration on page 248--the last zoea stage. From this it changes -directly to /Megalops/; the /Zoea/, seeming to be attacked with -violent convulsions, wriggles out of its skin a full /Megalops/ (page -248). The animal then has enormous eyes, an extended abdomen, an -elongated carapace, and swimming-legs. This stage is a short one, and -at the first moulting changes to a form nearly approaching the adult. -From this time they grow by shedding the shell at certain periods. -This shedding is supposed to occur twice each summer until they have -reached full growth, after which it is probable that they do not -again moult; for often they are found with extraneous organisms, -such as barnacles and sponges, upon them, of a size that must have -required a considerable period of time for growth. The sexes of -the same species sometimes differ so much that it is difficult to -classify them. Even naturalists have been led into the error of -assigning the male and female to separate species. - -The front side margins of the carapace in many crabs are edged with -a row of teeth or with spines, which vary in number and character -in different species. In the spider-crabs the whole surface of the -carapace is generally studded with tubercles, spines, and stiff hairs -of a peculiar character. This armature is for protective purposes, -and is often used to secure foreign bodies, such as algae, hydroids, -and polyzoans, which the crabs place upon their backs to disguise -themselves. The burrowing crabs are usually smooth. When in motion -the crab moves sideways, using the legs [pg274] of one side to pull -with and those of the other side to push with. As all the legs do -not move at the same time, a continuous and uniform motion is kept -up. Some species move with great rapidity, notably the sand-crab, -/Ocypoda arenaria/. Often when pursued they will run into the surf -instead of to their holes. The common edible crab, /Callinectes -sapidus/, of the Atlantic coast, the fiddler-crabs, and the -spider-crabs are among the well-known representatives of /Brachyura/. - - -FAMILY ~PORTUNIDAE~ - -SWIMMING CRABS - - -GENUS ^Carcinides^ - -[Illustration: /Carcinides maenas/, the green crab.] - - ^C. maenas^ (M. J. Rathbun), ^Carcinus maenas^ (Leach), the green - crab. This is one of the most common species on the Atlantic coast - from Cape Cod to New Jersey, and is very abundant in Vineyard - Sound, Buzzard's Bay, and Long Island Sound. It is found between - tide-marks, frequently well up on the beach, hiding under loose - stones, also in tide-pools and in holes and cavernous places on - the shore. It is from one and a half to two inches long, and a - little more in breadth. It has five acute teeth on each side of the - anterior part of the carapace. Its color is green, spotted with - yellow, making it quite conspicuous. The surface of the carapace - and limbs is more or less granulated. The posterior feet are - flattened to form swimming-paddles. It is a very lively creature - and has reckless audacity when brought to bay, which justifies its - specific name (which implies frenzy). The French call it /crabe - enrage/. [pg275] - - -GENUS ^Callinectes^ - -[Illustration: /Callinectes sapidus/, the blue crab.] - - ^C. sapidus^ (Mary J. Rathbun), ^C. hastatus^ (Stimpson), the blue - crab. This is the common edible crab of the Atlantic coast. It is - known at the North as the "blue crab," and at the South as the - "sea-crab." It is found from Cape Cod to Florida, and after the - lobster is the crustacean which has the greatest commercial value, - being taken in immense quantities for the markets, not only when - the shell is hard, but immediately after moulting, before the new - shell has hardened, when it is known as the "soft-shelled crab." - It inhabits muddy shores, and is common in bays and at the mouths - of estuaries. The carapace is about twice as broad as it is long, - and has a long, sharp spine on each side which projects outward. - This is a distinguishing feature. There are eight short spines on - each side between the long spines and the eyes; then come recesses - for the eyes, and between the eyes are four unequal teeth and a - small spine underneath. The chelae are large and somewhat unequal - in size; then come three pairs of simple feet and a fifth pair, - which are flattened, forming swimming-organs. The margins of the - carapace and abdomen are fringed with fine hairs, as are also most - of the joints of the limbs. The upper surface of the body and claws - is dark green in color, the lower surface is dingy white, the feet - blue, and the tips of the spines reddish. The body is compressed, - the carapace being moderately convex above, and is covered with - minute granulations, which are more numerous over some portions - than over others. The abdomen of the female is very broad and fills - the entire space between the bases of the posterior pair of feet. - During the spawning season it is so charged with eggs that often - it projects out almost at right angles with the carapace. The - [pg276] crabs of this species are very active and can swim rapidly. - They also have the habit of pushing themselves backward into the - mud for concealment. They are predaceous and pugnacious, and have - great strength in their claws, which they use with dexterity. - They not only fight their own kind, but show a bold front to all - enemies, including man. The average size is six inches across the - carapace. - - -GENUS ^Ovalipes^ - -[Illustration: /Ovalipes ocellatus/, the lady-crab.] - - ^O. ocellatus^ (Rathbun), ^Platyonichus ocellatus^ (Latreille), - the lady-crab or sand-crab. A species common on sandy shores from - Cape Cod to Florida. It is found among the loose sands at low-water - mark, even on the most exposed beaches, and also is abundant on - sandy bottoms offshore. At low-water mark it buries itself up - to the eyes and antennae in the sand, where it watches for prey - and foes, and quickly disappears beneath the sand when danger - approaches. It possesses the power of burrowing in common with - other marine animals which inhabit exposed beaches of loose sand. - By burying itself deep in the sand it is protected from the action - of the breakers. This species is easily distinguished by the color - and shape of its carapace, taken in connection with its posterior - swimming-feet. The body is nearly as long as it is broad, with - five prominent spines on each side. The front margin is indented - on each side of a three-spined rostrum, to form cavities for the - eyes. The first limbs are large and have claws; the posterior ones - are flattened into swimming-feet, and the intermediate three pairs - are simple in structure, ending in points. In color it is white, - covered with spotted rings of red and purple. [pg277] - - -WALKING CRABS - - -FAMILY ~CANCROIDAE~ - - -GENUS ^Cancer^ - -[Illustration: /Cancer irroratus/, the rock-crab; male.] - - ^C. irroratus^, the rock-crab. This is the common crab of the New - England coast. It ranges from Labrador to South Carolina, but is - rare south of New Jersey. It is found on sandy as well as on rocky - shores at and below low-water mark and also between tide-marks, - hiding among rocks, nearly buried in sand or gravel, and in - tide-pools, where sometimes amusing combats between the males may - be seen. The carapace is suboval, one third broader than long, - the breadth being often from three to four inches. The surface is - granulated but smooth; the color is yellowish, closely dotted with - brown. The eyes are on short stalks in deep, circular holes, and - between the eyes are small teeth. There are nine blunt teeth along - each side of the front edge of the carapace. The first pair of legs - are short and stout, and terminate in claws. The four posterior - pairs are slender and end in pointed tips. This is an edible crab, - and it is devoured by the larger fishes, but does not--although - there seems to be no reason for it--share to any extent a place in - the markets with the blue crab, /Callinectes sapidus/. - -[Illustration: /Cancer borealis/, the Jonah crab; male.] - - ^C. borealis^, the Jonah crab. This crab resembles, and is - frequently taken for, /C. irroratus/. It is larger than the latter - in full growth, and is heavier and more massive. The carapace and - claws are rougher, the granules being irregular in size. The legs - are proportionately shorter and heavier. The teeth on the anterior - margins are rounded in front, but the posterior ones are sharply - pointed. In color [pg278] it is brick-red above and yellowish - beneath. It inhabits rocky shores only and is found at low tide on - the surface of the rocks, where it is exposed to the action of the - waves and also to the attacks of birds of prey, which feed upon - it, while /C. irroratus/, concealed under the rocks in the same - locality, escapes their depredations. This species is supplied to - the Newport market, where it is considered preferable to the blue - crab. Its range is from the eastern end of Long Island to Nova - Scotia. - -[Illustration: /Cancer magister/, the common crab of the Pacific -coast; male.] - - ^C. magister.^ This species inhabits the Pacific coast and ranges - from Alaska to Lower California. The adult male is from seven to - nine inches broad and from four to five inches long. The anterior - margin of the carapace is an almost regular elliptical curve with - nine small teeth on each side. At the end of the curve a large, - pointed tooth projects directly outward, and from this the carapace - slopes abruptly backward, giving a narrow posterior end. The - surface of the carapace is undulated and covered with papillae, and - is light reddish-brown, shading to lighter color in the back. The - color of the legs and under surface of the animal is yellowish. - The claws are toothed above and ribbed at the sides. It inhabits - sandy bottoms below tide-mark and is the largest and most important - edible crab of the western coast. - - ^C. productus^, the red crab. This species, like the preceding one, - is of large size and inhabits the western coast from Alaska to - the Gulf of California. The carapace is four and a half inches in - length, from five to seven in breadth, and somewhat elliptical in - outline. The teeth on the anterior margin are distinctly separate - in the adult, but in the young appear as wrinklings of the edge - of the carapace. The posterior margins are concave. In color the - animal is dark red above and yellowish beneath in the adults, but - variable in the young, sometimes being yellow spotted with red, - or banded with red and yellow. It inhabits rocky shores. This is - an edible crab, but is not taken for the markets, /C. magister/ - supplying all demands. [pg279] - -[Illustration: /Cancer productus/, the red crab; male.] - -[Illustration: /Cancer antennarius/, the California rock-crab.] - -[pg280] - - ^C. antennarius^, the rock-crab of the Pacific coast. This - species of the California coast inhabits rocky bottoms below - low-water mark. The carapace is three and a half inches long by - five or six inches wide, and dark purplish-brown in color. The - chelae are marbled with purplish spots and are nearly smooth. The - distinguishing features of this crab are its large and hairy - antennae, the hirsute margins of its abdomen and walking-feet, and - the numerous hairs on the under side of its body. - - -GENUS ^Menippe^ - -[Illustration: /Menippe mercenaria/, the stone-crab; male.] - - ^M. mercenaria^, the stone-crab. This species lives in deep holes - in the mud along the borders of creeks and estuaries, and also - in crevices between fragments of rock, in stone-heaps and other - debris, and is found from South Carolina to Texas. These crabs are - edible, and in some localities are hunted for food, one manner - of capturing them being to thrust the hand and arm into their - holes and drag them out, an operation attended with danger to the - inexperienced hunter, who is likely to be badly pinched. They are - withdrawn with difficulty, as they offer a strong resistance, - bracing themselves with their claws against the sides of their - holes, and often hold so firmly to the rocks that they are torn - [pg281] apart. They are also taken by a hooked iron which is thrust - into the hole; the crab seizes it and is then suddenly jerked from - its hole. The adult measures about three by four and a half inches, - and the body is from one inch to two inches thick. One of the chelae - is larger than the other, and both are proportionately enormously - large, and are tipped with black. The terminal joints of the other - four pairs of legs are thickly fringed with hairs and end in points - which seem like nails. - - -FORMER GENUS ^Panopeus^ - -[Illustration: /Eurypanopeus depressus/, the mud-crab; male, natural -size.] - - ^Eupanopeus herbstii^, ^Eurypanopeus depressus^, ^Neopanopeus - texana^, ^Rhithropanopeus harrisii^ (Mary J. Rathbun). These four - species, formerly all called /Panopeus/, are small crabs which live - in the mud and are commonly known as mud-crabs. They are abundant - under stones in muddy places, and occur on the Atlantic coast from - Massachusetts Bay to Florida, though they are not commonly met with - north of New Jersey. /Eupanopeus herbstii/ is the largest one of - the group, some of the Southern ones measuring two inches across. - It is found living in mud at low-water mark, or burrowing in banks - near high-tide mark. It is dark olive-brown, the claws broadly - tipped with black. /Eurypanopeus depressus/ is flattened above, - and is smaller than /Neopanopeus texana/, which is somewhat convex - above. The last two are commonly found together and have similar - habits. /Rhithropanopeus harrisii/ lives near high-water mark and - also in salt-marshes, and is comparatively rare. The claws lack the - dark tips of /E. herbstii/, and a distinct groove follows the edge - of the carapace. - - -FAMILY ~GRAPSIDAE~ - - -GENUS ^Hemigrapsus^ - - ^H. nudus^ (Mary J. Rathbun), ^Heterograpsus nudus^ (Stimpson); - ^H. oregonensis^ (Mary J. Rathbun), ^Heterograpsus oregonensis^ - (Stimpson). These two species, commonly called respectively the - /purple shore-crab/ and the /yellow shore-crab/, are the most - abundant species of the California coast. Hundreds may be found - congregated under a single rock. They range from Sitka to Lower - California. /H. oregonensis/ literally swarms in sloughs of salt - or brackish water, and hundreds of uplifted threatening claws - confront the intruder who ventures on these mud-flats when the tide - is out. This species, the yellow shore-crab, has a nearly square - body. The anterior half of the side margins has two rather deep - indentations, [pg282] making two spine-like projections which bend - forward. The four posterior pairs of legs are more or less hairy; - the chelae are rather large in proportion. The male is about one - inch across and the female is one third less in size. The general - color is yellow. /H. nudus/ is found in the same localities, and - differs from /H. oregonensis/ in being purple in color, with - mottled claws, and in having the denticulations less pronounced - and the walking-feet devoid of hairs. It is also a little larger. - (Plate LXIII.) - - -GENUS ^Pacygrapsus^ - - ^P. crassipes.^ A species very common on the California coast south - of San Francisco. This crab is similar in general features to the - purple and yellow ones described above, but is considerably larger, - and the carapace is banded with color. - - -FAMILY ~OCYPODIDAE~ - - -GENUS ^Ocypoda^ - - ^O. arenaria^, the sand- or ghost-crab. The name /Ocypoda/ means - "swift-footed," and, as it implies, this species is especially - noted for its rapidity of movement. These crabs are the opposite - of the strong-armed, thick-shelled, slow-moving /Cancroidae/. An - instance is told of a collector having great difficulty to keep up - at full run with one which he chased for a considerable distance - over the sand. They are also dexterous in burrowing, and live in - holes, often three feet deep, dug perpendicularly into the sand. - They wander far from their burrows when the tide is out, and - every little while raise their stalked eyes and stand on tiptoe - to look about. If alarmed, they run with great rapidity to the - nearest burrow, or, if danger is close, press themselves on the - sand until an attempt is made to touch them, when they again dart - away rapidly, and in running hold their bodies high, and double - and dodge so that it is difficult to catch them. /Ocypoda/ is - colored almost exactly like the sand, and this mimicry, together - with its fleetness, makes it interesting to note and difficult - to capture. It inhabits sandy beaches above tide-mark from Long - Island to Brazil, and subsists largely upon the beach-fleas, which - inhabit the same localities. It springs upon them, very much as a - cat catches a mouse. The carapace of this species is almost square - in outline, and on the anterior corners ends in a spine. A small - portion of the carapace folds down like a band between the eyes. On - each side of this band, and extending across the front, are large - grooves for the eye-stalks. The body is about an inch thick; the - first joints of the chelae are toothed; one chela is a little longer - than the other, and both are coarsely granulated. The other four - pairs of legs are thickly fringed with hairs. (Plate LXIII.) - -[Illustration: PLATE LXIII. Hemigrapsus nudus. Hyas araneus. Ocypoda -arenaria. Pugettia gracilis. Libinia dubia. Pitho aculeata.] - -[Illustration: /Uca/ (/Gelasimus/) /pugilator/, the fiddler-crab; -male.] - - -GENUS ^Uca^ - - ^U. minax^ (^Gelasimus minax^), ^U. pugnax^ (^Gelasimus pugnax^), - ^U. pugilator^ (^Gelasimus pugilator^), the fiddler-crabs. These - species [pg283] of fiddler-crabs occur on the Atlantic - coast. They congregate in immense numbers, and excavate their - holes in convenient localities above the reach of the tides--on - salt-marshes, far up the estuaries, and along the mouths of rivers, - even where the water is quite fresh. The males have one claw very - largely developed; the other chela is small. The former is likened - to a fiddle, the latter to a bow, and this, together with the - waving motion of the large claw, gives them their popular name. - This comparatively enormous claw is a distinguishing feature by - which they are easily recognized without other description. The - female has claws of small and equal size. These crabs burrow holes - in the mud or sand half an inch to two inches in diameter and a - foot or more in depth. The upper part is nearly perpendicular, - becoming horizontal below, with a chamber at the end. One species, - /U. minax/, constructs an archway over the mouth of its burrow, in - which it sits and surveys the surroundings, but quickly retreats - when danger approaches. The crab makes its burrow by scraping up - the mud or sand and forming it into pellets, which it carries under - the three anterior walking-feet on the under side, using the legs - on the side moving forward, and the fourth one on the other side, - to climb out of the hole. After peering cautiously about, the - crab emerges, and carries its load four or five feet away before - dropping it; then again looks about before quickly running back; - and, finally, turning its stalked eyes, looks in all directions - and suddenly disappears, soon to return with another load. The - burrows cover considerable areas, and the crabs are so abundant - that the marshes and shores sometimes seem to be alive with them. - When alarmed, they lift the large claw and run sideways, after - the manner of all crabs, to their holes, and, as many are likely - to retreat into the most convenient one, the owner often finds - his burrow occupied by other tenants, whom he unceremoniously - proceeds to pull out. /U. minax/ ranges from southern New England - to Florida, and lives on salt-marshes farther away from the sea - than the others, and often where the water is quite fresh. It - is larger than the other species, and can be distinguished by a - red patch at the joints of the legs. It is a vegetarian in diet, - living on small algae. This is the species which constructs a little - observation-house over the mouth of its burrow. It can live out of - water, and without food, for several days. /U. pugilator/ lives - on sandy and muddy flats and beaches near high-water mark, where - the sand is compact and somewhat sheltered, and ranges from Cape - Cod to Florida. This species, like /U. minax/, is a vegetarian. - /U. pugnax/ is exceedingly abundant on muddy banks and ditches of - salt-marshes, the banks being sometimes completely honeycombed and - undermined by them. It ranges from Cape Cod to Florida. [pg284] - - -FAMILY ~MAIIDAE~ - -The members of this family are known as "spider-crabs." Their bodies -are thick and more or less round in form, narrowing in front to -a long, beak-like projection. The surface is generally rough and -irregular, having tubercles, spines, prickles, and hairs. The legs -are long. These crabs are often covered with seaweeds, hydroids, -and other organisms, which they gather with their long and flexible -chelipeds and place upon their backs, presumably to conceal -themselves from their enemies. They seem to select, instinctively or -with reason, such things as will bear transplanting, sometimes using -sponges and polyps which are not destroyed by being torn apart, and -they also select their dress with reference to its masking uses. A -/Hyas/ covered with bright-colored algae was seen to remove them and -replace them with sponges, when transferred to the locality of the -latter, where the former did not grow. The animal takes in his claw -the object he has gathered, and first holds it to his mouth, where it -is moistened with a secretion of mucus or cement, and then places it -on his back. If it does not hold, the operation is repeated, often -several times, a new spot on the shell being selected each time. It -has also been found that the coats of these crabs are covered with -hairs which are differently arranged in different genera, some being -hooked, others serrated, etc., and that these aid in holding the -transplanted organisms in place. The crab is sometimes so covered -with these growths as to be entirely concealed beneath them. It is a -sluggish animal, and inhabits shallow water along the whole of the -Atlantic and Pacific coasts. - - -GENUS ^Libinia^ - - ^L. dubia^, ^L. emarginata^. These two species inhabit the - Atlantic coast, and are found on muddy shores and flats, among - decaying seaweed, in eel-grass, and even beneath the surface of - the mud. They are covered with hairs, and sometimes have planted - on their backs algae, hydroids, and even barnacles. The legs of /L. - emarginata/ often spread a foot or more. The males are much larger - than the females. The species ranges from Maine to Florida. /L. - dubia/ does not extend north of Cape Cod. It is found more commonly - than /L. emarginata/ in very shallow water [pg285] near shore. It - is not so thickly covered with spines, and has a longer rostrum, - which is also more deeply divided at the end. (Plate LXIII.) - - -GENUS ^Hyas^ - - ^H. coarctatus^, the toad-crab. This species of spider-crab is - found from Greenland to New Jersey, in shallow as well as in deep - water. Its body resembles strongly, both in form and size, that of - a toad, hence its common name. It forms an important part of the - food of the cod. - - ^H. lyratus.^ A toad-crab of the Pacific coast, ranging from Bering - Sea to Puget Sound; named from the lyre-shape of its carapace. - - ^H. araneus.^ A species which especially resembles a toad in its - form. Found off the northern New England coast. (Plate LXIII.) - - -GENUS ^Loxorhynchus^ - - ^L. crispatus^, the sheep-crab. This crab occurs on the coast of - southern California. The body is thick and about three inches - across the widest portion, and tapers to a long, prominent rostrum. - It is covered with long tubercles and spines and with short, - bristly hairs; the legs are long, the chelipeds stretching fully - two feet. - - -GENUS ^Pugettia^ - - ^P. gracilis.^ A small spider-crab found on the Pacific coast from - Alaska to Puget Sound. Its body is one half of an inch wide and - [pg286] one inch long, with prominent spines on the sides of the - carapace, which narrows in front into a long beak ending in two - spines. It is red and green above, red beneath. (Plate LXIII.) - - -GENUS ^Sternorhynchus^ - - ^S. sagittarius.^ This is one of the most delicately formed of the - spider-crabs. The body has narrow longitudinal stripes of light and - dark color. It lives offshore from Cape Hatteras southward. - -[Illustration: /Epialtus productus/, the kelp-crab; female.] - - -GENUS ^Epialtus^ - - ^E. productus^, the kelp-crab. This crab inhabits the coasts of - California and Oregon, and is found among seaweeds on rocks just - below low-water mark. The carapace is smooth, is quadrate in form, - is about two inches long and broad, has two spines on each side, - and has a prominent denticulated rostrum. This is the most common - spider-crab of the Pacific (California) coast. It is olive-green, - thus simulating in color the kelp among which it lives. (See page - 285.) - - -GENUS ^Pitho^ - - ^P. aculeata.^ The carapace has six spines on each side, the - middle two being sometimes partly united; the general outline is - pentagonal; the length about one inch. Quite common on the Florida - coast. (Plate LXIII.) - - -GENUS ^Lambrus^ - -[Illustration: /Lambrus pourtalesii./] - - ^L. pourtalesii^, the long-armed spider-crab. The carapace is - broader than it is long and has three elevations all covered with - spines. The general surface is pitted and granulated; the rostrum - points downward; the chelipeds are very long, the margins armed - with spines; the breadth of the carapace is about one and a half - inches; and the length of the chelipeds is about three and a half - inches. Its range is from Cape Cod to Florida, and it lives among - the rocks. (Plate LXIV.) [pg287] - - -FAMILY ~CALAPPIDAE~ - - -GENUS ^Calappa^ - - ^C. flamma^, the box-crab. This singular animal lives on sandy and - muddy bottoms offshore, from North Carolina southward. The carapace - is broad and straight on the posterior side, and is curved on the - anterior side, narrowing to the front. The posterior side has - prominent denticulations. The body is one and a half inches thick, - about four to five inches wide, and two to three inches long. - The chelae are large, broad, and flattened, and are so arranged - that when flexed they fit closely together across the front. When - folded, and the small legs are withdrawn under the carapace, the - animal is shut up as if in a box, and resembles a shell. When in - danger it closes its doors, as it were, and abandons itself to the - waves, which often carry it ashore. The crested claws resemble the - head of a cock. (Plate LXIV.) - - -FAMILY ~PINNOTHERIIDAE~ - - -GENUS ^Pinnotheres^ - -[Illustration: /Pinnotheres ostreum/, the oyster-crab; male, enlarged -four diameters.] - - ^P. ostreum^, the oyster-crab. The female of this species lives - in the gill-cavity of the oyster, and is particularly abundant in - oysters from the Chesapeake. The males are seldom seen, and rarely - occur in the oyster, but swim freely about. They are smaller than - the female, have a firmer shell, and are dark brown above, with a - dorsal stripe and two conspicuous spots. The under side of the legs - is whitish. The female is commensal, at least in the adult form, - and its thin, whitish, transparent carapace is tinged with pink. - The species ^P. maculatum^ lives in /Mytilus edulis/ (mussel) and - in the smooth scallop, /Pecten magellanicus/. The oyster-crab is a - true messmate, and its presence in the oyster may be advantageous - in helping to provide food for its host. This crab, like the rest, - holds its eggs in the posterior feet until hatched, when the larvae - leave the parent and swim about for a while. The females, at the - megalops stage, enter oysters--sometimes two enter the same oyster, - but seldom more than one; there it remains permanently, growing to - the size of an inch or more in diameter, and becomes a degenerate. - The eyes become smaller; the shell never hardens, like its allies - which live in open water; its limbs and chelae are weak; and it has - no pugnacity, the protection afforded by the oyster doing away with - the need for the common protective features of its kind. /Pinnixa - cylindrica/, a related species, lives in the tubes of large annelid - worms as a commensal. [pg288] - - -ORDER =STOMATOPODA= - - -GENUS ^Squilla^ - -[Illustration: /Squilla empusa/, the mantis-shrimp.] - - ^S. empusa.^ This animal suggests somewhat the lobster, though very - unlike it. The carapace is much smaller and softer, and leaves - the last three segments of the thorax uncovered. The abdomen is - larger and longer in proportion, while the legs and organs are - quite different. The whole body is depressed, instead of laterally - compressed. It measures from eight to ten inches in length and two - inches in breadth. Instead of chelae, the last joint of the great - claw has six sharp curved spines, which fit into sockets in a - groove on the second joint. By this singular organ they hold their - prey securely. The abdominal feet carry the gills. The antennal - scales are oblong and fringed with hair. The antennules terminate - in three flagella. The caudal appendages and telson are long, - strong, and armed with spines. This animal lives in burrows in the - mud below low-water mark, forming large, irregular holes, but is - frequently washed ashore. In color it is pale yellowish-green, each - segment being bordered with darker green and edged with yellow. It - is found from Cape Cod to Florida. - - -ORDER =CUMACEA= - - -GENUS ^Diastylis^ - - ^D. quadrispinosus.^ Among the minute /Crustacea/ which swim on the - surface of the water, this species, with other small forms, may be - captured by using a muslin net. It is a quarter of an inch or less - in length. It is easily distinguished by its large carapace, the - posterior portion of which is marked off in transverse ridges, the - anterior end running into a sharp-pointed rostrum. It has a long, - slender abdomen, the sections of which [pg289] are distinctly - marked, and it terminates in long, forked spines, which are longer - than the telson. It is found from New Jersey northward. - - -ORDER =ARTHROSTRACA= - - -SUBORDER ~AMPHIPODA~ - -The /Amphipoda/ have a laterally compressed body, with gills on the -thoracic feet and an elongated abdomen. The segments of the thorax -are not united, nor covered by a carapace, but the whole body is -covered with a segmented, polished, flexible cuticle. The three -anterior legs of the abdomen are for swimming-feet, and the posterior -ones are adapted for springing. The antennae are long and hairy. The -amphipods comprise the beach-fleas and many other small crustaceans -which abound between tide-marks on all beaches. Besides serving in no -small measure as food for fishes, they are scavengers of the beach, -and consume large quantities of waste matter. They are sometimes -used in preparing skeletons for anatomical specimens. Animals to be -skeletonized, being fastened to boards and anchored just below the -surface of the water in sheltered places, are divested of all flesh -in a few hours, and the bones are more completely cleaned than if -prepared by a naturalist. - - -GENUS ^Orchestia^ - -[Illustration: /Orchestia agilis/; male.] - - ^O. agilis^, the beach-flea. These little crustaceans exist in - countless numbers under the masses of sea-wrack on the beach. When - disturbed they jump about with great agility by means of the last - three pairs of abdominal feet, which are adapted to this purpose. - In color the animal is brown and much resembles the decaying - seaweeds among which it lives and upon which it probably feeds. The - antennules are short, the antennae long, on two long, jointed bases. - The second pair of feet in the males terminate in chelae. The last - abdominal appendages are stiff and pointed backward. The abdomen is - curved under. The length of /Orchestia/ is half an inch or less. - Some species occur on all beaches. /O. agilis/ ranges from New - Jersey to Greenland. - - -GENUS ^Talorchestia^ - - ^T. longicornis^ (^Talitrus longicornis^). This species is similar - to Orchestia agilis, but is about an inch long when mature and - of a paler [pg290] color. It jumps like the latter, but not so - strongly. It is found among the weeds and burrowing in the sand - a little below high-water mark. The wet sand is often completely - filled with its holes. It can be distinguished by its very long - antennae. Another species, ^T. megalophthalma,^ is distinguished by - its shorter antennae and very large eyes. Both of these species are - grayish in color and closely resemble the sand. Found from Cape Cod - to New Jersey. - - -GENUS ^Gammarus^ - -[Illustration: /Gammarus locusta/, the scud.] - - ^G. locusta.^ The animals of this genus are among the largest of - the amphipods. The males are larger than the females, sometimes - being one and a half inches long. They are abundant under stones - and /Fucus/ at and near low-water mark. Although much larger than - the beach-fleas, they otherwise resemble them. They do not jump - like the former, but move rapidly, lying on the side, and in water - swim with the back downward. Two pairs of the thoracic feet are - chelate, and three pairs are longer than the others. The feet - on the last segments of the abdomen are stiff and turn sharply - back, forming a part of the tail, which is used most effectively - in locomotion. The antennules and antennae are of about the same - length. Several species of /Gammarus/ occur in the same range, all - having the same general characteristics; some have but one pair of - chelate feet; the antennules are usually shorter than the antennae; - the females of all the species have no chelate feet. /G. locusta/ - ranges from New Jersey to Greenland. The color is generally - reddish- or olive-brown. ^G. annulatus^ is found in the same - places, but usually a little higher up on the beach; it is lighter - in color, and has dark bands with red spots on the sides of the - abdomen. ^G. mucronatus^ occurs from Cape Cod to Florida. ^Melita - nitida^ is a smaller slate-colored amphipod found in some places; - another is ^M[oe]ra levis^, which is whitish, with black eyes. - -[Illustration: /Chelura terebrans/, the boring amphipod.] - - -GENUS ^Chelura^ - - ^C. terebrans^, the boring amphipod. This little crustacean - is associated in its work on submerged timber with the isopod - /Limnoria lignorum/. The excavations of the latter are narrow and - cylindrical, running down into the wood, while /Chelura/ makes - larger burrows in oblique lines near the surface, which give the - wood the appearance of having been plowed. It is very active and - destructive. It feeds upon the wood into which it burrows. Its - color is semi-translucent, thickly mottled above with pink. [pg291] - - - -GENUS ^Caprella^ - -[Illustration: /Caprella geometrica./] - - ^C. geometrica.^ These very curious little animals, which are so - slender as to seem like skeletons, are found in abundance clinging - to hydroids, /Polyzoa/, delicate algae, or eel-grass, or under - stones in tide-pools. They resemble in color, and often in form, - the objects on which they live. Holding on by the posterior feet, - they extend the body out rigidly or sway it about, so that they - resemble little sticks or branches, and often escape detection. In - walking, they bring the hind feet up to the front ones, doubling - the body into a loop like the canker- or measuring-worm. The - appendages on the anterior and posterior ends are furnished with - chelae and hooks; those of the middle section are rudimentary. This - animal cannot be mistaken for any other. /C. geometrica/ is found - from Cape Cod to North Carolina. Some of the species of this genus - may be found on every coast. - - -SUBORDER ~ISOPODA~ - -The isopods have an elongate, flattened, but more or less arched -body, composed of seven thoracic segments and a short abdomen of -six segments. The six segments of the abdomen are smaller than -those of the thorax, and are often more or less united, sometimes -into a single piece with scarcely any trace of division above; but -the number of pairs of appendages is generally six, showing the -composite nature of the apparently simple organ. The last segment, -or telson, is broad and has a pair of modified appendages. The seven -thoracic legs are not all equal, as the name would imply, but vary -greatly in different species. As a rule, they are adapted to walking -or attachment, and in the female some have delicate plates which -form brood-pouches. The swimming-feet fold under the abdomen, and -in some species are inclosed by the first pair, which are large and -plate-like, and form a complete cover for the others. The isopods -are a large and widely distributed order, varying in size, and -are inconspicuous because they cling closely to objects. They are -retiring in habit, though extremely ferocious. - -The sow-bugs or pill-bugs, common in gardens, under leaves in the -woods, and under almost any pile of rubbish among decaying vegetable -matter, are a land species of isopods. Other species inhabit [pg292] -ponds and streams of fresh water, and still others are found along -the shores of all oceans, abounding among the marine vegetation -of the shallow waters. Some swim free in the open sea; others are -brought up from the greatest depths. Others, again, are parasites, -and live in the internal organs of fishes and prawns. Sometimes -a prawn is found having what appears like a very swollen throat, -which actually is a little parasitic isopod of the family /Bopyridae/ -attached to its gills. - - -GENUS ^Cirolana^ - -[Illustration: /Cirolana concharum./] - - ^C. concharum.^ The body consists of fourteen segments, the first - being the head, the next seven the thorax, and the last six the - abdomen. On the head are the triangular eyes, the antennules, and - the antennae, and underneath is the mouth, which is covered by the - maxillipeds. The dorsal surface is more or less rounded. At the - bases of all the segmental thoracic rings excepting the first one - are sutures marking off square, scale-like pieces (/epimera/). The - epimera form a border to the side margins. The legs are attached to - the epimera, which are, in fact, the upper segments of the legs. - The first three pairs of legs have a general resemblance to one - another, and are directed forward. The last four pairs are much - longer and flatter, and are directed backward. The telson, or last - segment, is triangular, and the square or blunt apex is fringed - with hairs. On the ventral surface of the thorax in the adult - females there is a long pouch for the reception and development - of the eggs. This species is usually about one and a half inches - in length, but sometimes is longer. Its color is yellowish, with - a brown edge on the posterior margins of the segments, somewhat - translucent in the thinner parts. It is found from Cape Cod to - South Carolina, swimming about in shallow water, and is especially - abundant in winter. - - -GENUS ^Limnoria^ - -[Illustration: /Limnoria lignorum/, the gribble.] - - ^L. lignorum^, the gribble. This little isopod is very destructive - in its habits, boring into submerged woodwork, like the ship-worm - (Teredo), and doing great damage to the piles of wharves, etc. It - burrows to the depth of half an inch, and completely honeycombs - the surface of the wood, which then scales off or rapidly decays, - and is washed away by the waves. The animal then begins anew, - and in a short time, or at the rate of about an inch a year, - piles diminish in diameter where /Limnoria/ is plentiful, and are - finally destroyed unless protected from these little crustaceans - by a sheathing of metal. Although considered as pests, they have - an economic value not so often recognized, as they attack all - driftwood, and in time entirely destroy floating and water-logged - [pg293] timber, which without their destructive agency might become - serious obstructions to navigation. /Limnoria/ is only the fifth - of an inch in length, and its back is covered with minute hairs, - to which dirt usually adheres. It burrows with its mandibles, or - jaws, which are chisel-like at the ends. Its habitat extends from - a little above to a little below tide-marks throughout the whole - Atlantic coast. - - -GENUS ^Sphaeroma^ - - ^S. quadridentatum.^ The name of the genus to which this species - belongs is derived from the peculiar habit of many of the species - of rolling themselves into a ball when alarmed. The body is so - constructed as to admit of this singular change of shape. The - abdomen turns under, and the last abdominal appendages, together - with the narrow epimera, shut in the legs and cover the ventral - portions with armor. The body, when extended, is an ellipse a - little over a quarter of an inch in length and half that in - breadth. The legs are hairy and adapted to walking. The anterior - abdominal segments are fused into one, but are marked at the sides - with depressed lines. The abdominal feet are plate-like and fringed - with hairs. A slight elevation runs around the margins of the - animal like a border. The color is variable. Some are a uniform - slaty gray; others are marked with a longitudinal patch of color - on the back. It is found from Cape Cod to Florida among algae or - rocks, and is easily recognized by its habit of rolling itself - into a ball. ^Sphaeroma destructor^ is a boring isopod, larger than - /Limnoria/, and is even more destructive, since its holes are - larger; but its range is limited, or, at least, it has so far been - found only in the St. Johns River, Florida. - -[Illustration: /Sphaeroma quadridentatum./] - - -GENUS ^Idotea^ - -[Illustration: /Idotea marina./] - - ^I. marina^ (Linnaeus), ^I. irrorata^ (Edwards). This species is - about one inch long, and is easily recognized by the abdomen, the - first three segments of which are narrow and terminate in acute - teeth, while the other three are fused into one with straight sides - and ending in three teeth, of which the middle one is the longest. - The first pair of abdominal feet are large, long, and plate-like, - covering the other feet and whole under surface of the abdomen like - an operculum. The head is nearly square, the eyes are small, and - the antennae have long peduncles. The articulations of the thoracic - feet are fringed with hair. The color of this species varies: - sometimes it is light or dark green, or brown with black spots; - again [pg294] it is striped longitudinally with light color. - Sometimes the stripes run transversely in bands or spots. It is - found from New Jersey northward on rocky shores of bays and sounds, - or in eel-grass on sandy shores. - - ^I. ochotensis.^ A species very similar to the preceding, but a - little larger, found on the Pacific coast. - - ^I. metallica.^ This species is a little smaller than /I. marina/, - and differs from it in having the end of the telson truncated, or - straight, instead of dentate. The head is nearly square. The body - is broadest in the middle of the thorax; the projecting epimera - give a serrate appearance to the sides. The abdominal feet are - inclosed in the operculum-like scales of the first pair of feet. - Its color is bright blue or green, often with a metallic luster - when seen in the water. It is found swimming free or floating in - masses of seaweeds from Long Island northward and also on the - Pacific coast. - - ^I. wosnesenskii.^ A common species on the California coast, - about one inch long and dark in color. The abdominal segments are - united and bluntly rounded, and each has a small median tooth. The - abdominal feet are inclosed by the opercular feet. Eggs and young - are carried in a pouch. - - -GENUS ^Chiridotea^ - -[Illustration: /Chiridotea caeca./] - - ^C. caeca.^ This species burrows beneath the surface of the sand, - raising it up into a little ridge, and makes a mound at the end of - the burrow, where it may be found. These trails are common on the - wet sand. It imitates the sand in color, and is about half an inch - in length, with a broad thorax and narrow abdomen terminating in a - point. It is found on the New England coast. - - ^C. entomon^ (Linnaeus). This species of the northern Pacific coast - is from one to three inches long. The head has the appearance of - two lobes, the sides having two rounded ends. The body is broad, - the abdomen narrowing to a pointed end. The last segments of the - abdomen are united, and the abdominal feet are inclosed by the - first pair, which extend over them like an operculum. The epimera - are broad, with acute lateral angles. - - - - -CLASS =MERISTOMES= - - -ORDER =XIPHOSURA= - - -GENUS ^Limulus^ - -[Illustration: Under surface of horseshoe-crab, /Limulus polyphemus/: -/a/, abdomen; /c/, cephalothorax; /g/, the first gill-bearing -abdominal appendage; /m/, mouth; /o/, operculum; /p/, telson; /s/, -metastoma; 1-6, cephalothoracic limbs.] - - ^L. polyphemus^, the horseshoe- or king-crab. This well-known - and curious animal ranges along the Atlantic coast from Maine - to Mexico. [pg295] It lives on sandy and muddy shores below - low-water mark, where it burrows beneath the surface. At the - breeding season--May, June, and July--it comes ashore to deposit - its eggs near high-water mark. The crabs come up the beach in - pairs, the male being the smaller and riding on the back of the - female, holding on by short feet provided with nippers, which - are peculiar to the males. Sometimes the female is accompanied - by several males, each one holding on to the tail of another and - forming a string of animals. After the female has deposited her - eggs in a hole excavated by her for the purpose, the male covers - them with milt, and they then return to the water, leaving the - eggs to be buried in the sand by the action of the waves. The eggs - hatch in July and August, and sometimes the beach is literally - alive with the young crabs, which, however, soon disappear, and - are not seen again until they are well grown. After the spawning - season the adults are not very often seen, but usually their empty - shells, abandoned in moulting, may be found on the shore. The - horseshoe-crab, also called king-crab, is especially interesting - from the fact that it is the last survivor of an otherwise extinct - group of animals. Its relationships with classes which have become - extinct, its nearest relatives being fossils, make it difficult - to classify definitely with existing forms. Formerly it was - regarded as a crustacean; now it is classed by some authors with - the /Arachnida/, along with scorpions and spiders. It has the - characteristics of both groups. There are only two known species of - /Limulus/ in the world; the other, ^Limulus moluccanus^, lives on - the eastern coast of Asia. /L. polyphemus/ often measures a foot in - diameter. The body is composed of three parts. The front portion, - or cephalothorax, is broad and semicircular, with posterior angles - ending in points. Near each side of its dorsal surface is a pair of - large compound eyes covered with thickened cuticle, and near the - center line of the shell, at the base of the first spine, a pair - of small, simple eyes. The second portion is the abdomen, and the - third a long, movable spine attached to the last segment of the - abdomen and between two terminal points of the horn-like covering. - [pg296] On the cephalothorax are seven pairs of appendages. The - first pair are small and lie in front of the mouth; these and - the four following pairs have chelae, or claws. The sixth pair - have no chelae, but at the base have a peculiar process termed the - flabellum. These six pairs of appendages surround the mouth, and - have bristles at the base which serve as jaws. The seventh pair of - thoracic appendages are broad plates called the operculum, which - meet and cover the abdominal appendages to a certain extent. The - abdomen has five pairs of appendages, which are plate-like and - resemble the operculum in form and have an upper and an under - piece. On the posterior surfaces of the abdominal feet are large, - leaf-like folds, which are the gills. In front of the first pair - of thoracic legs is a small tubercle supposed to have an olfactory - function. /Limulus/ has a blood-vascular system (the blood being - bluish in color), a nervous and a digestive system. It walks with - the thoracic feet and swims with the abdominal ones. It enters - the sand by pushing in the rounded, anterior end. In moulting the - carapace opens on the front edge. /Limulus/ is edible, its meat - being, it is said, as good as that of the lobster. (Plate LXIV.) - - - - -CLASS =PANTOPODA= (Lang) - - -ORDER =PYCNOGONIDA= - -This order of animals, like /Limulus/, has no definitely determined -position in the classification of marine organisms. About one hundred -and fifty species of /Pycnogonida/ have been described, of which -thirty are found on our coast and are commonly known as sea-spiders. -They are found crawling slowly over seaweeds, hydroids, and sponges, -and appear to be all legs, but, like other animals, have a digestive, -a circulatory, and a nervous system. They are devoid of organs of -respiration. The body has a cephalothorax, which bears a conical -suctorial proboscis on the anterior end, and on top a prominence -containing four eyes. It has three pairs of appendages, two pairs -of which are sometimes lacking; then come three free segments and -a rudimentary abdomen. There is a pair of short appendages bearing -claws (chelae) and four pairs of long walking-legs. The walking-legs -contain a tubular outgrowth of the body, into which the stomach -extends. The egg-sacs are in the legs, and open at the basal joints. -The male is provided with an extra pair of legs, for the purpose of -carrying the eggs after they are deposited by the female. The -[pg297] ovigerous legs are run through sac-like pockets and bent -under the body, and thus the eggs are carried until hatched. - -[Illustration: PLATE LXIV. Calappa flamma. Calappa flamma, claws -open, showing form of cockscomb. Lambrus pourtalesii. Limulus -polyphemus.] - - -GENUS ^Phoxichilidium^ - - ^P. maxillare.^ This species is found on the New England coast - creeping over hydroids and ascidians. It is purple, gray, or brown - in color. Its young take shelter in the cavities of hydroids, - forming galls. - -[Illustration: /Phoxichilidium maxillare/, enlarged.] - - - - -VII - -MOLLUSCA - - -TABLE SHOWING THE CLASSIFICATION OF THE MOLLUSKS DESCRIBED IN THIS -CHAPTER - - Phylum =MOLLUSCA= - - Class =AMPHINEURA= (/Bilaterally symmetrical mollusks, having - shell composed of eight plates, or devoid of shell. Including - chitons and their allies/) - - Order =POLYPLACOPHORA= (/Shell composed of eight plates/) - - Order =APLACOPHORA= (/Devoid of shell/) - - Class =GASTEROPODA= (/Unsymmetrical univalve mollusks, usually - spirally coiled. Periwinkles, whelks, snails, etc./) - - Order =OPISTHOBRANCHIATA= (/Branchiae, when present, behind - the heart/) - - Suborder =TECTIBRANCHIATA= (/Branchiae more or less covered - by mantle; shell delicate and often rudimentary/) - - Suborder =NUDIBRANCHIATA= (/Devoid of shell and mantle, and - without true branchiae/) - - Order =PROSOBRANCHIATA= (/Branchiae situated in front of the - heart/) - - Suborder =DIATOCARDIA= (/Usually two auricles, two - branchiae, and two nephridia/) - - Suborder =MONOTOCARDIA= (/One auricle, one branchia, one - nephridium/) - - Order =PULMONATA= (/Air-breathing mollusks/) - - Class =SCAPHOPODA= (/Mollusks without head, eyes, or heart, - with trilobed foot and tubular shell open at both ends. The - tooth-shells/) - - Class =PELECYPODA= (/Bilaterally symmetrical, headless, bivalved - mollusks. Mussels, cockles, oysters, etc./) - - Order =PROTOBRANCHIATA= (/Gills form a single pair of - plume-like organs, each with two rows of flattened - gill-filaments/) - - Order =FILIBRANCHIATA= (/Two pairs of plate-like gills formed - of V-shaped filaments/) - - Order =PSEUDOLAMELLIBRANCHIATA= (/Gills plaited so as to form - vertical folds/) - - Order =EULAMELLIBRANCHIATA= (/Firm, basket-work gills, the - filaments united by vascular connections/) - - Class =CEPHALOPODA= (/Mollusks of high organization, having - a definitely formed head surrounded by tentacles; shell, - when present, usually internal; shell, external in nautili. - Cuttlefishes, squids, octopi, and nautili/) - - Subclass =Tetrabranchiata= - - Subclass =Dibranchiata= - - Order =OCTOPODA= - - Order =DECAPODA= - -[pg302] - - -TERMS USED IN DESCRIBING MOLLUSKS - -^Abductor muscles^: Muscles which move parts away from the axis. - -^Adductor muscles^: Muscles which draw parts together; opposite of -/abductor/. - -^Aperture^: Opening of the spiral shell. - -^Bilateral symmetry^: Having two equal sides, divided by a central -axis. - -^Branchiae^: Gills, or breathing-organs; organs subservient to -respiration through water. Same as /ctenidia/. - -^Buccal mass^: The mouth-parts as a whole; the organ of prehension -and mastication of food; the pharynx: present in all mollusks except -lamellibranchs. - -^Canal^: A narrow prolongation of the aperture of a spiral shell. - -^Carinated^: Ridged as if keeled; having a keel. - -^Cinereous^: Ash-gray; having the color of wood-ashes. - -^Cirri^, plural of ^Cirrus^: Filamentous appendages. - -^Columella^: An upright pillar in the center of most of the univalve -shells, round which the whorls are convoluted. - -^Concrescent^: Growing together; uniting. - -^Cordate^: Heart-shaped. - -^Costae^, plural of ^Costa^: Ridges of a shell. - -^Crenulated^: Having a series of notches; marked as with notches, as -the indented margin of a shell. - -^Crystalline style^: A transparent gelatinous substance of unknown -function, which fills, at times, the stomach-parts of certain -mollusks. - -^Ctenidia^, plural of ^Ctenidium^: Gills, or breathing-organs, -adapted to water-respiration. [pg303] - -^Decussated^: Crossed; intersected. - -^Dextral^: Having the aperture on the right side of the shell when -the apex is upward. - -^Epidermis^: The horny coating or outer skin of some shells. - -^Foot^: The ventral surface of the body on which the animal rests or -moves. - -^Fossette^: A little hollow or pit. - -^Fuscous^: Brown tinged with gray; swarthy. - -^Fusiform^: Tapering both ways from the middle. - -^Lamelliform^: Lamellate in structure; disposed in leaf-like layers. - -^Lingual ribbon^: The chitinous band of teeth, or rasp, borne upon -the odontophore; the radula. - -^Lunule^: An impressed area just below the beaks of bivalve shells. - -^Mantle^: A fleshy or membranous outgrowth of the outer body-wall; -also called /pallium/. - -^Mantle cavity^: The space between the mantle and the body. - -^Monomyarian^: Having one adductor muscle, as an oyster. - -^Nephridium^: The renal organ of mollusks, corresponding to kidneys -in vertebrates. - -^Node^: A knob or protuberance; also a notch in the margin. - -^Odon'tophore^: The lingual ribbon bearing chitinous teeth. - -^Oper'culum^: A horny or shelly plate which serves to close the -aperture of the shell when the animal is retracted. - -^Osphra'dia^, plural of ^Osphradium^: Olfactory or water-testing -organs. - -^Otocyst^: The cavity, or cyst, which contains the essential parts of -an organ of hearing. - -^Pallial line^: The impression or mark made by the mantle, or -pallium, on the inner surface of a bivalve shell. - -^Pallial sinus^: A notch or recess of the pallial line; the scar of -the siphon. - -^Papillaceous^: Warty; studded with bosses; having excrescences. - -^Perios'tracum^: Same as /epidermis/. - -^Per'istome^: In zooelogy, mouth-parts in general; in conchology, the -margin of the aperture of the shell. [pg304] - -^Porcelanous^: Resembling porcelain. - -^Rad'ula^: Same as /lingual ribbon/. - -^Reticulated^: Having distinct lines or veins crossing like a -network; covered with netted lines. - -^Sculpture^: Elevated or impressed marks on the surface; markings -resulting from irregularity of surface; tracery. - -^Sinistral^: Having the aperture of the shell at the left; opposite -of /dextral/. - -^Sinuate^: Curved in and out; wavy. - -^Siphon^: A tubular fold, or prolongation of the mantle forming a -tube. - -^Spire^: All the whorls of a spiral univalve, above the first large -body-whorl. - -^Suture^: The line of junction of the successive whorls of a univalve -shell, or the line of closure of the opposite valves of a bivalve -shell. - -^Teeth^: Tooth-like projections on the hinge of a bivalve shell. - -^Testaceous^: Having a hard shell, as distinguished from crustaceous, -or soft-shelled. - -^Turbinate^: Shaped like a whipping-top; whorled from a broad base to -an apex. - -^Umbilicus^: A central, navel-like depression in the body-whorl; a -circular, more or less central pit or hollow. - -^Umbo^: The beak of a bivalve shell; the protuberance of each valve -above the hinge. - -^Varices^, plural of ^Varix^: Raised marks on the shell denoting a -former position of the lip of the aperture, and indicating periods of -rest. - -^Varicose^: Having prominent and tortuous formations on the shell. - -^Ventricose^: Having the whorls of the shell swollen or strongly -convex. - -^Whorl^: One of the turns of a spiral shell. /Body-whorl/, the last -whorl. - -[pg305] - - - - -MOLLUSKS - - -We now come to another large and important group of animals, with -characters so peculiar to itself and differing so radically from -those which distinguish any other class of living creatures, that -it may be said to occupy almost a unique position in the animal -kingdom. Recent investigations have demonstrated that the larval -form of mollusks presents some remarkable points of similarity to -the embryonic forms of the /Annelida/ and to the larvae of some other -classes of lower organisms. This discovery is one of the triumphs -of embryology in its patient search for that connecting-thread that -weaves together all the varying forms of animal life. Aside from -these subtle evidences of relationship revealed by the microscope, -the mollusks appear to occupy a position of considerable isolation in -the biological world. - -As accepted by zooelogists to-day, this phylum is but the remnant of -its former self. Aristotle considered all creatures with a testaceous -covering to belong to a single family, and those later patriarchs of -biology, Linnaeus, Cuvier, and Lamarck, extended the group to include -the greater part of all the marine invertebrate animals. Little by -little the phylum has been shorn of orders and classes. First, the -worms and the /Echinodermata/ were separated into distinct phyla; -then the barnacles were discovered to be crustaceans, and were -accordingly removed from their position as "multivalves" under the -/Mollusca/; then the tunicates, or ascidians, were found, through the -critical examination of their larval stage, to be merely masquerading -as mollusks; and lastly, the brachiopods have been somewhat -reluctantly removed from their old position with the mollusks and -given the [pg306] distinction of a phylum almost exclusively to -themselves: they retain their old associations only in the name of -/Molluscoida/. - -With some exceptions, all mollusks secrete from their outer skin, or -mantle fold, a calcareous protective covering, or shell. This may be -either "univalve" or "bivalve" according as it consists of one or two -pieces. This phylum includes all the sea-shells which are so commonly -found along every ocean beach, in the tide-pools, on rocks at low -tide, in estuaries, and, indeed, wherever sea-water is present. The -phylum also includes, as one of its large suborders, all the snails -and slugs that are to be found crawling upon the land. These are true -mollusks, which differ essentially from their marine brethren only in -that they breathe by means of a pulmonary sac or lung instead of by -gills. There are also many genera and species of mollusks that find -their habitat only in the fresh water of rivers, lakes, or ponds; -curiously enough, many of these fresh-water forms, like the purely -terrestrial snails and slugs, are air-breathers, possessing no gills -whatever, and are consequently obliged to make periodic visits to -the surface of the water to obtain their necessary supply of oxygen. -There are also numerous forms of mollusks that are entirely deprived -of a shell covering; and, again, there are intermediate types -between these two extremes that produce only more or less developed -rudimentary shells. Notwithstanding these variations in the matter -of a shell covering,--an important consideration in this phylum,--by -reason of their anatomical features these "naked" forms are mollusks -quite as much as are those that secrete the most highly developed -tests. - -The marvelous beauty of sea-shells and tropical land-shells, -their almost infinite variety in form and coloring, has given to -them an interest among collectors that is very great. There are -many wonderful conchological collections in public museums and in -private cabinets. It would well repay the lover of beauty as well -as the more serious student of nature to examine carefully such -collections when opportunity offers, for nowhere in the realm of -nature can more exquisite coloring and modeling be found. The fact -that shells may be preserved for all time without the expense and the -vexations of preservative fluids has no doubt induced many [pg307] -to choose this field of natural history for special study. But the -true student of zooelogy does not confine his investigations in this -phylum to considerations of the shell only, for the protective -armor constitutes only a portion, although an important portion, of -the anatomy of the mollusk. On the same principle, it would hardly -suffice to examine only the skeleton of vertebrate animals in order -to become acquainted with the fishes or mammals. In a sense, the -testaceous covering of a mollusk may be likened to an outer skeleton. - -The older zooelogists were inclined to ignore almost entirely the -animal or "soft parts" of mollusks, and their classification of -the phylum into "univalve," "bivalve," and "multivalve," based -upon shell-characters alone, has since been proved to be wholly -artificial. The terms "univalve" and "bivalve" are, of course, often -and correctly used to-day to designate mollusks possessing a single -or a double shell, such as the common garden-snail, which carries -upon its back a single spiral shell, and, on the other hand, the -oyster or clam, which is inclosed within two valves which fit closely -together. But these terms are not /technically/ used, although -they do indicate in a general way the more modern classification. -Even among some comparatively recent conchologists a tendency to -belittle the value of the "slimy creature" within the shell has led -to some curious errors of grouping--mistakes which more thorough -and scientific investigation has brought to light. In general, the -higher classification into classes, orders, suborders, and families -is exclusively based upon anatomical features, and to a large extent, -also, is that of the genera; but species are always determined by -their shell or conchological characteristics. - -When a certain familiarity with the forms and general appearance of -shells is gained, a glance at the shell alone will almost always -suffice to place it at once in its true generic position, for, along -with modifications of the animal itself, corresponding modifications -of the shell are quite certain to take place. Hence a fairly expert -zooelogist should be able to determine with considerable accuracy from -an empty and dead shell the anatomical features of the animal that at -one time inhabited it. [pg308] - -One of the main reasons for the special interest that seems to have -attached to the study of conchology is derived from the fact that the -durability of shells has caused their almost perfect preservation -as fossils from the very earliest periods of geological time, thus -furnishing the key to the solution of many problems of evolution. -Upon this page of the earth's history the letters are sharp and -clear, and geologists possessing a knowledge of recent forms of -mollusks as well as of their geographical distribution have been -enabled to read some wonderful stories of the cosmic history of -islands and continents. - - -GEOGRAPHICAL DISTRIBUTION - -Mollusks are found in every part of the world. The arctic seas -possess their own characteristic faunae, the more temperate waters of -Europe and of America contain their own peculiar genera and species, -and the warm waters of the tropic seas furnish the conditions -favorable to the life of an immense number of characteristic forms. -Again, there are the littoral species, that live only between -tide-marks and are therefore exposed to the air for a number of -hours each day; some of these live just about high-tide mark and -have become almost terrestrial in their habits, while others must be -sought at the point of lowest tide, where for only a short time each -day they are deprived of their natural element. Then there are the -shallow-water forms, which never appear above low-tide mark save when -a neap tide surprises them; their range in depth extends to about -the hundred-fathom line, more or less. Beyond this depth to several -hundred fathoms other characteristic forms appear, and from the more -profound depths of mid-ocean the dredge has brought to light a host -of curious and interesting species. - -It is the temperature of the water rather than the depth that appears -to influence the distribution of marine mollusks. Thus, certain -species whose natural home is in the shallow waters of the Arctic -Ocean have been taken in very deep waters off the southern coast of -the United States, the temperature conditions in both stations being -substantially the same. This fact, however, must not be too freely -accepted as establishing a principle. Some [pg309] shallow-water -forms have been taken at great depths, but in general the abyssal -fauna is a peculiar one that cannot well be marked off into -geographical provinces. - - -THE ARCTIC PROVINCE - -The east coast of America is divided into several molluscan -faunal regions. A series of very-cold-water forms belonging to a -circumpolar region, called the "arctic province," are found as far -south as Newfoundland. On the New England coast a number of these -arctic species are also found, urged south by the influence of the -cold Labrador current. The most characteristic genera belonging to -this arctic fauna which are found upon the Maine and Massachusetts -coasts are /Buccinum/, /Chrysodomus/, /Sipho/, /Trophon/, /Bela/, -/Velutina/, /Trichotropis/, /Lacuna/, /Margarita/, /Pecten/, /Leda/, -/Yoldia/, /Astarte/, and /Mya/. Examples of all these genera are -encountered as far south as Cape Cod. - - -THE BOREAL PROVINCE - -A "boreal province" corresponds with a similar faunal region upon -the European shore. The mollusks which compose this fauna are about -three hundred in number, and range along the New England coast from -the Gulf of St. Lawrence to Cape Cod. It is a somewhat remarkable -fact that many of these species are identical with English and French -forms. The striking genera upon the American side are /Purpura/, -/Littorina/, /Polynices/ (/Lunatia/ and /Neverita/), /Acmaea/, -/Margarita/, /Chiton/, /Doris/, /AEolis/, /Mytilus/, /Modiola/, -/Thracia/, and /Nucula/. - - -THE TRANSATLANTIC PROVINCE - -Cape Cod has been regarded, until very recently, as a sharp -divisional point between the boreal and the transatlantic provinces, -the latter faunal area extending down the Atlantic coast of the -United States to southern Florida. At Cape Cod the Labrador current -is deflected from the coast, and the warmer shore waters south of -that point are unfitted for the development of the boreal forms, -though some of them, as we shall see, have passed the [pg310] -barrier and maintain themselves very successfully at Martha's -Vineyard and in Long Island Sound. Some of the species whose natural -habitat is south of Cape Cod are also to be found north of that -point, but they do not reach their full development in the colder -waters of Massachusetts Bay. - -The long stretch of coast-line from Cape Cod to Florida is easily -susceptible of faunal subdivision at Hatteras, below which locality a -decided mixture of Antillean species is apparent. Between Long Island -Sound and Hatteras the littoral molluscan fauna is disappointing -to the collector, for the number of species is relatively small, -and few even of these are entitled to any claims to beauty of -shell. The nature of this coast, virtually a great sweep of exposed -sand-beach, is not conducive to a varied or rich fauna. But if this -portion of the transatlantic province is lacking in interest to -the shell-collector, it is anything but disappointing to the army -of men employed in the oyster- and clam-fishery. It is only within -this faunal area that the American oyster, /Ostrea virginica/, the -best of the edible shell-fish, finds its natural home, and here the -oyster-culture is most extensively carried on. - -After storms the Jersey beaches are frequently strewn with /Mactra/, -/Tagelus/, /Arca/, and /Ensis/; in more sheltered places /Fulgur/ and -/Polynices/ (/Lunatia/) are commonly met. These may be accepted as -the most characteristic genera of this province. - -Just south of Cape Hatteras an observer is struck with the sudden -change in the appearance of the shells on the beach. /Cardium/, -/Cassis/, /Dolium/, /Arca/, and /Cancellaria/ at once suggest -the West Indies. About the vicinity of Hatteras the Gulf Stream -approaches very near the land, bringing with its warm waters many -wanderers from tropical homes. From Beaufort to Florida there is -another long stretch of exposed and shifting sand-beach, which offers -a scant return to the collector of mollusks. - - -THE CARIBBEAN PROVINCE - -When Florida is reached a new world is opened to the naturalist, -for there a better acquaintance is made with the great Caribbean -province, which, extending from Florida to the northern shores of -South America, embraces all the Bahamas, the West [pg311] Indies, -the Gulf of Mexico, and the coast of Central America. Strangely -enough, the mollusks of the west coast of Florida are more nearly -related to those of the transatlantic province than are the shells -of the east Florida coast. This remarkable fact in geographical -distribution can only be explained by assuming that an open waterway -once existed across the northern part of the Florida peninsula, -connecting the Atlantic and the Gulf, through which a mingling of the -shallow-water forms from Georgia, the Carolinas, West Florida, and -the Gulf coast took place. Thus it would appear that when Florida -was an island the fauna of its east coast, originally largely -Antillean, was less disturbed by the southern migration of American -species. The Florida Keys are essentially Antillean. The Caribbean -or Antillean fauna is an exceedingly rich and varied one. Among the -most prominent genera which may be encountered upon the Florida coast -are /Strombus/, /Fasciolaria/, /Oliva/, /Marginella/, /Natica/, -/Sigaretus/, /Littorina/, /Tectarius/, /Neritina/, /Melongena/, -/Cardium/, /Callista/, /Tellina/, /Lucina/, and /Cyrena/. In such an -extensive and rich faunal province one must not expect to find in any -given locality a representation of all the characteristic genera. For -instance, collections made at Havana, at Nassau, and at Vera Cruz -would each contain forms more or less peculiar and local, but certain -species would be found in each collection. - - * * * * * - -On the west coast of America quite the same faunal division into more -or less well-marked provinces is to be found. Bering Sea belongs to -the arctic province, and contains, with Labrador and Greenland, many -identical forms. - - -THE ALEUTIAN PROVINCE - -The shore waters from the southern peninsula of Alaska down to about -Vancouver comprise the Aleutian province. Within this area occur -some arctic species, notably the soft-shell clam, /Mya arenaria/, -which the fishermen gather in such large quantities for bait along -the Maine coast. An increasing number of species common to this -west-coast faunal region and to the boreal province of the east coast -are being recorded. Some of [pg312] these have been introduced from -the East by the agency of man, but others no doubt have a natural -range through the icy waters north of America and down through the -Bering Sea into the Pacific. - - -THE CALIFORNIAN PROVINCE - -The Californian province extends from the neighborhood of Vancouver -to Cape St. Lucas and has about five hundred species. The northern -portion of this area contains some very characteristic forms, -together with a good mixture of species of more northern habitat; -it might properly be regarded as a subprovince. From San Diego -south to the cape the character of the fauna gradually changes; -this coast-line of southern California has also been considered a -subregion. The main characteristic of the Californian province is a -large development of /Haliotis/, of the patelliform mollusks, and -of the chitons. A very few minutes on any good collecting-beach -of California would convince the Eastern conchologist that he had -entered upon an entirely new field of research. The most notable -genera are /Calliostoma/, /Chlorostoma/, /Scurria/, /Acmaea/, various -genera of the /Chitonidae/, /Purpura/, /Monoceras/, /Amphissa/, -/Norrisia/, /Olivella/, /Chorus/, and /Haliotis/. - - -THE PANAMIC PROVINCE - -The warmer waters of the Gulf of California belong to the Panamic -province, which extends down to South America. This is one of the -richest and most interesting faunas in the world. At Panama alone, -Mr. C. B. Adams, a noted collector and student of conchology, took -upward of four hundred species. About eight hundred species are known -in the Gulf of California alone. - - * * * * * - -It must be borne in mind that these faunal provinces relate to -littoral and shallow-water species, for the present knowledge of -deep-water forms is not sufficient to permit of generalization upon -their distribution. - -We review here only the conspicuous forms along our own coasts. It -may be well to note, however, that in some other parts of the world -the development of molluscan life is far [pg313] in excess of -anything to be found upon our shores. The veritable paradise of the -naturalist is the East Indies. There the "aristocratic" genera, so -called on account of their marvelous beauty, occur in their highest -development--/Voluta/, /Mitra/, /Oliva/, /Conus/, and the various -murices. There also are to be found the pearl-oysters, /Meleagrina -margaritifera/, that yield their valuable harvest, and the giant -clam, /Tridacna gigas/, which measures sometimes five feet in -length. Over eight thousand species of mollusks are described from -this surpassingly rich region, yet this vast province, as compared -with the American and European shores, has been but superficially -exploited by the naturalist. In whatever part of the world a -naturalist may find himself, there is always a tempting array of -molluscan life to attract him. Each fauna possesses features peculiar -to itself, and from the point of view of the true naturalist, the -more somber-hued and conventionally formed mollusks of Northern -shores are no less interesting than the gorgeously tinted and -fantastically shaped species of the tropics. From any faunal province -of our own country one may readily gather all forms necessary to -furnish ample material for study from which one may acquire an -excellent idea of the biological features of the entire phylum. - - -STATION AND HABITS OF THE MOLLUSCA - -The word "station" is used to indicate the nature of the surroundings -which an animal chooses as most suited to his well-being. Some groups -of mollusks, like the littorinas, the trochids, the purpuras, and the -majority of those having patelliform shells, generally live on rocks -above low-tide mark; other genera, like /Buccinum/, /Sipho/, and -/Chrysodomus/, prefer rocky or gravelly ground below low-tide mark. -Other mollusks burrow deep in the mud, many prefer sandy bottoms, -while a host of other species seek homes upon the tangled masses of -seaweed, living like arboreal creatures in the submarine forests. -Nearly every conceivable character of sea-bottom or shore-line -between tides harbors its own peculiar types of molluscan life. There -are some very curious genera of bivalves that bore their way into the -hardest rock and [pg314] there find a comfortable shelter for life. -A numerous class of pelagic or free-swimming mollusks supposedly -never go to the bottom at all, but spend the whole of their existence -on or near the surface of the sea, always in open water, where -their fragile shells may not be injured by rough contact with solid -substances. - -The food of some is vegetable, of others, animal. The bivalves, like -the clams, oysters, cockles, and mussels, feed only on microscopic -organisms. They create a current of water through their siphons, or -mantle openings, and then, by a process best known to themselves, -catch and swallow all the animalculae thus brought to their mouths. -The univalves which possess a siphon are, for the most part, -carnivorous, and are often most voracious creatures. They feed upon -any animal matter they can find, while some of them are enabled by -means of a sharply toothed tongue to bore through the solid shells -of other mollusks and extract the succulent vitals from within. One -energetic little mollusk in particular, /Urosalpinx cinerea/, is -for this reason a great pest upon the oyster-beds. Univalves not -possessed of a siphon may generally be considered herbivorous; they -pass most of their time peacefully browsing upon algae. - -Mollusks are all oviparous or ovoviviparous; that is, they lay eggs, -or, laying eggs, they retain them within their shells until the -young are hatched out. As a rule, each species of mollusk has its -own particular method of protecting its eggs from external injury. -Some construct tough, leathery capsules which are strung together in -various patterns. The egg-capsules of /Purpura lapillus/, resembling -little pinkish or yellowish club-shaped stalks, may frequently -be found in the crevices of rocks and under the rockweeds. The -egg-cases of /Polynices/ (/Lunatia/) are most peculiar, resembling -inverted gelatine-bowls with the bottom knocked out; when wet they -are semi-elastic translucent masses in which may be seen myriads of -eggs. /Buccinum undatum/ arranges its hemispherical egg-capsules -in layers one above the other. The number of eggs so deposited is -often very great, running well into the thousands. Egg-capsules of -/Fulgur/ are leathery coils of angular disks adhering by one edge to -a connecting-band of a similar texture. (See Plate I.) [pg315] - -In bivalves the eggs are retained within the parent shell until -hatched, and the young, which then escape into the water, are very -different-looking creatures from the parent. Generally the young -bivalve is free-swimming and exceedingly lively in its movements; -sometimes by means of cilia it is enabled to attach itself to any -passing host, and thus the species is widely disseminated. The fry -soon lose their embryonic form and take on the characteristics of the -adult. - -The longevity of mollusks varies greatly with the species. Some -attain an age of from ten to fifteen years, while some are only -annuals. Oysters continue to grow for four or five years, after -which they may survive many years more. In truth, little is known -concerning the duration of life even of our better-known shore -species. - -In point of intelligence, mollusks must be relegated to a very -low position. They give evidence of possessing no more than -the most primary instincts, those of self-preservation and of -reproduction. There are some forms that exercise a high degree of -protective mimicry. The highest class of mollusks, the /Cephalopoda/ -(cuttlefishes, octopi, etc.), is widely separated from the other -classes in the development of faculties that appear to correspond -with intelligence. They are exceedingly crafty in the pursuit of -their prey as well as in eluding capture. - - -STRUCTURE OF MOLLUSKS - -Among the invertebrate animals, especially in the lower orders, wide -physiological departures from central or typical forms are frequent. -It often happens that a whole group or even suborder will differ -so materially in its general characteristics from another group -or suborder belonging to the same phylum that the student will be -puzzled at first to understand how the two can be nearly related. In -many such cases it is only when the essential features of the phylum -are thoroughly understood that the relationships of its suborders -can be appreciated. An example of widely divergent groups within the -same phylum has already been shown in the /Echinodermata/. Who would -at first suppose that the graceful /Astrophyton/ could bear kinship -to the inert [pg316] holothurian, or that both of these have the -closest family ties with the sea-urchins? - -The probable reason for these startling departures from a typical -form is that in the lower orders of life, where the organs and their -functions are comparatively simple, the laws of evolution operate -far more quickly in the adaptation of an organism to environment and -changed conditions of life. A decided tendency to this departure from -the type is a feature of the mollusks. It would be difficult, if -not impossible, to give a general description that would fit both a -common garden-snail and the common oyster, yet both are mollusks. A -concise definition of the phylum is therefore practically impossible, -and it seems here as if nature resented all attempts to circumscribe -her living forms by rigid rules. - -The most persistent characteristic of the /Mollusca/ is the -possession of the "mantle," a sort of outer skin which, like a bag or -sack, envelops the creature above and about the sides, but is open -below, permitting the animal at will to protrude or withdraw its -foot. From the outer surface of this sheath-like mantle, or fold, a -calcareous shell is secreted. The modifications of this mantle are -infinite; indeed, in some well-marked groups it seems to have wholly -disappeared, having in reality become fused to the sides of the -animal, and having become therefore a mere outer skin, and no longer -a tunic or cloak, as originally intended. As already noted, the -mantle does not always secrete a shell, a fact which again reminds us -that we cannot give a good comprehensive description of the phylum -that always holds true throughout its subdivisions. The best that can -be done is to give in general terms the characters which appear in -a majority of the forms. A convenient method of going about this is -to create, for the sake of clearness, an ideal, model, or fanciful -mollusk and clothe it with all the most salient molluscan features, -and from such a basis to develop, as we go on, the various types of -the actual orders and suborders. There is one class of mollusks, -the /Amphineura/, which conforms reasonably well in most of its -features to our comprehension of the schematic mollusk. This class is -sometimes referred to by biologists as the "primitive" or "original" -mollusks, from which all the other classes have since been derived; -but the [pg317] evolutionary history of the development of the -various molluscan orders through geological time does not seem to -bear out the fact that an "ideal" mollusk, as we shall construct him, -ever actually existed, or that his prototype, the /Amphineura/, was -the first and consequently the ancestral type of the phylum. We must -therefore only accept this ideal mollusk theoretically, to serve as -a guide for the time being. We may profitably use it only as a lay -figure--a sort of manikin, which will introduce us to the phylum. -After our introduction we must forget our imaginary type and abandon -any notion we may have conceived of the parental position of the -/Amphineura/, its closest imitator in actual life. - - -THE IDEAL MOLLUSK - -The ideal mollusk has a compact, somewhat elongated body, the under -or ventral portion of which is thickened into a muscular disk, upon -which it creeps along. This disk is called the /foot/. (Note a snail -thus crawling upon his "foot.") The foot is rounded or obtusely -pointed posteriorly. Forward, the body is slightly narrowed into -a neck, and then expanded again into a head. Upon this head are -carried two projecting, mobile, fleshy tentacles, one upon each -side, that superficially resemble two horns. At the base of each -tentacle, upon the inner side, is an eye. Just below and between the -tentacles is a small horizontal slit,--the mouth,--the lips being -slightly thickened. The visceral portion of the animal is above the -foot, or /dorsal/ to it, and extends the whole length of the animal -from the mouth to the excretory opening, the latter being situated -posteriorly. The visceral cavity is inclosed above by a thin skin; -indeed, it is but the great thickening of this skin below that -constitutes the foot. - - [Illustration: Ideal or schematic mollusk. - - 1, dorsal view: /h/, head; /t/, cephalic tentacle; /sh./, shell - covering visceral mass; /b.m./, outline of body-mass; /r.m.e./, - edge of mantle; /c.t./, ctenidia, or gills; /q.a./, generative - apertures; /r.e./, renal openings; /e.o./, excretory opening; /f/, - posterior portion of foot; /o.e.m./, edge of shell. - - 2, ventral view: /h/, head; /t/, tentacle; /m/, mouth; /b/, outline - of body; /e.m./, edge of mantle; /s.f./, lower surface of foot; - /c.t./, ctenidia, or gills; /f/, posterior portion of foot. - - 3, horizontal section, showing heart, nephridia, and gonads: - /m/, mouth; /o/, esophagus; /g/, gonad; /p/, pericardium; /n/, - nephridium, or renal organ; /v/, ventricle; /a/, auricles; /g'/, - gonad aperture; /n'/, renal opening; /e/, excretory opening; /f/, - posterior portion of foot. - - 4, vertical median section: /m/, mouth; /b.m./, buccal mass; /l/, - liver; /d.a./, digestive tract; /q/, gonad; /f/, foot; /q.o./, - gonad aperture, or opening of oviduct; /r.o./, renal opening; - /e.o./, end of digestive tract, excretory opening; /n/, mantle; - /r/, nephridium, or renal organ; /o.f./, recurved portion of - mantle; /sh./, shell; /v/, ventricle; /p/, pericardium.] - -The digestive tract, beginning at the mouth, opens immediately into a -muscular throat, which is called the /buccal mass/. Within the buccal -mass there is a long, fleshy ribbon that bears upon its upper surface -numerous rows of sharp teeth; these rows of teeth run crossways on -the ribbon, each row containing more or less prominent median teeth, -with several laterals upon each side, and with marginal teeth on each -side of the laterals. This is called the /radula/, and is used for -tearing or rasping the food. When [pg319] not in use it lies coiled -up within the buccal mass. Beyond the buccal mass, food passes into -the esophagus, which widens out into a muscular pouch or stomach; -this may also be provided with chitinous teeth or hard knobs or -plates for the purpose of further triturating the food. Above and -partially surrounding the stomach is a large reddish or brownish -liver, which furnishes to the alimentary canal the digestive juices. -From the stomach the intestine leads to the terminal anal opening. -There are two organs, serving the function of kidneys, placed -dorsally one upon each side of the body (/nephridia/). A heart lies -within the median line of the body, and consists of a ventricle and -two lateral auricles. The vascular system is almost entirely closed; -only in so far as it is partially open does it essentially differ -from that of higher groups; the blood is whitish or light bluish, -and receives its oxygenation in the gills or along the free mantle -surface, through which it courses in exceedingly thin capillaries. In -this manner respiration is carried on to some extent throughout the -whole outer surface of the body. There are two /branchiae/ (gills). -These have the appearance of small feathers and are placed upon -each side of the animal posteriorly; they project slightly. Spread -over the top of this animal, fitting it perfectly, is a thin fleshy -covering attached to its dorsal portion like a skin, but hanging -free, like a flap, over the sides, the head, and the posterior end -of the animal. Upon the sides it may just cover the tips of the -branchiae, but in front the head is seen to project from under it. -The loose-hanging portion of this sac-like covering is somewhat -thickened, and perhaps recurved upward upon itself. Upon the edge of -this flap all the way around may occur a row of cilia, or tentacular -processes. This cloak-like covering is called the mantle, and, as -already noted, is the most peculiar and persistent characteristic -of the /Mollusca/. The "cavity" formed between the loose-hanging -portion of the mantle and the sides of the foot is called the /mantle -cavity/, and contains posteriorly the gills, or branchiae. From the -outer surface of this mantle a calcareous secretion takes place, -forming a shell, which, in our ideal mollusk, will be shaped in -conformity with the surface outlines of the mantle, oblong and convex -above. Over the lower portion of the shell the edge of [pg320] the -mantle recurves. When the creature is disturbed or is at complete -rest it may withdraw that portion of the mantle which protrudes from -below the shell entirely within the edge of the shell, so that the -"soft parts" may be wholly covered, and thus protected from harm. In -such a state of rest nothing may be seen from above but a shell. The -entire upper surface of the mantle is firmly attached to the under or -inner side of the shell, except the mantle margin, this being free. - -The nervous system consists of a circumesophageal ring of -nerve-cells, with two cords passing along the digestive tract to the -posterior end of the animal. In the head and above the buccal mass -are several series of nerve-ganglia. These also communicate with the -posterior portion of the animal through two parallel cords which pass -along its ventral side. From these four principal branches, which -traverse the entire length of the creature, minor nerve-cords are -thrown off to the tentacles, the foot, the branchiae, and the various -organs of the viscera. The sexes are separate. - -Reviewing our "typical mollusk," we find that it is bilaterally -symmetrical--that is, uniform upon both sides of a median line from -mouth to excretory opening; is unsegmented; has the ventral surface -thickened into a creeping foot or disk; and is possessed of a head -with tentacular processes, a radula, lateral branchiae, a heart with a -ventricle and two auricles, a well-developed mantle, and a shell. - -If the reader can learn these few details of organization he knows -the structure of a mollusk. In turning to the actual living forms he -will find merely modifications (though sometimes confusing ones) of -these various parts. - - -CLASSIFICATION - -The /Mollusca/ are divided into five great classes: /Amphineura/, -/Gasteropoda/, /Scaphopoda/, /Pelecypoda/, and /Cephalopoda/. These -names, it will be noticed, with the exception of the first, all refer -to the /foot/, the modifications of the foot being selected as the -basis of the first great divisions of the phylum. The /Gasteropoda/ -crawl upon the thickened ventral surface of their bodies (already -[pg321] referred to as the foot), as the common garden-snail, the -periwinkles, and in general all those mollusks which have a spirally -coiled shell. The /Scaphopoda/ have a long, worm-like foot, with -which they burrow in the sand or mud. Their shells are like miniature -elephant-tusks, but are open at both ends. The /Pelecypoda/ have a -more or less club-shaped foot, utilized, in the many families, for -a great variety of purposes. They are always inclosed in a bivalve -shell. Familiar examples are the oysters, the clams, mussels, etc. -The /Cephalopoda/ have the /foot/ modified into a number of /arms/, -which encircle the head or the mouth. They are the cuttlefishes, the -octopi, squids, etc. - - -CLASS =AMPHINEURA= - - -ORDER =POLYPLACOPHORA= - -The /Amphineura/, as already observed, approach most closely to the -ideal mollusk just described. They are bilaterally symmetrical. -This fact is so important that it constitutes them a class, -notwithstanding the fact that in respect to the foot (the basis of -division into classes) they would be included with the /Gasteropoda/, -for (barring some exceptional instances) they creep along upon a foot -quite as our ideal mollusk would, and as the /Gasteropoda/ do. The -head carries no tentacles, thus essentially differing in this respect -from the ideal form. The mantle is extended down in front, completely -covering the head. The branchiae are confined to a few pairs of -/ctenidia/, or plume-like gills, within the mantle groove or cavity, -and are arranged upon each side of the excretory opening like small -feathers. - -There are two orders of the /Amphineura/, the /Polyplacophora/ and -the /Aplacophora/ (or /Solenogastres/), the one name meaning "bearing -many plates," and the other "without plates," the word "plate" in -this sense being synonymous with "shell." The shell of the first -order consists of eight calcareous disks arranged in a longitudinal -row along the back or dorsal side of the animal, which overlap like -shingles on a roof and admit of great variation of form in the -various families. [pg322] - -It will be observed from the examples given that the shell plates do -not entirely cover the mantle, but that a considerable portion of the -upper mantle surface is left exposed along the side of the animal. -This exposed portion of the mantle is called the /girdle/. It is -always very much thickened and is often exceedingly tough. In some -species it is covered by a great number of calcareous spicules or -granules which are embedded in the leathery mantle tissue. Strangely -enough, the /Chitonidae/ (a large family of the /Polyplacophora/) -possess a great number of eyes scattered over the shell plates like -minute dots. - -[Illustration: /Chiton spinosus/, dorsal view.] - -The members of this order are to be found in all parts of the world, -but their greatest development is upon the west coast of America. -In California the student of marine life has a splendid opportunity -to examine the chitons. They are generally to be found adhering -to the under surface of stones about low-tide mark. They are very -sluggish in their movements and may readily be removed from their -resting-places by suddenly thrusting a knife-blade under the foot -and prying them off. When thus detached they have a habit of rolling -up into a ball and so remaining indefinitely; to prevent this they -should be placed at once in a jar of sea-water, where they will -resume their natural position. For preservation as cabinet specimens, -chitons should be tied down between two boards or flat substances, -to hold them firmly extended until dried; otherwise they are apt to -contract out of shape. - -[Illustration:/Chiton/, ventral view: /an/, anus; /cten/, ctenidia; -/ft/, foot; /mant/, mantle-edge; /mo/, mouth.] - -Six or eight species are exceedingly common upon the west [pg323] -coast. The collector who has successfully taken a number of these -will not fail to note the varying degrees of width of the girdle in -the different species. In some cases the girdle partially covers the -overlapping shell plates. The largest of all the chitons inhabits -the California shores and is known as ^Cryptochiton stelleri^. -It measures fully six inches in length and three in width. In -/Cryptochiton/ the girdle is continued over the shell plates as a -tough, gritty, brownish covering. The shell plates are white, and, -as detached pieces, are frequently to be found cast up upon the -California beaches, where, from their curious shape, they are often -referred to as "butterfly-shells." - -[Illustration: /Chiton ruber./ /Chiton apiculatus./] - -On the east coast of America there are comparatively few species, and -these are all small and inconspicuous. The three commonest ones are -^Chiton ruber^, ^C. albus^, and ^C. apiculatus^. They may readily be -found on stones or dead shells fished up from below low-tide mark, or -in rock-pools left by the receding tide. - - -ORDER =APLACOPHORA= - -This second order of the /Amphineura/ is entirely destitute of the -shell plates characteristic of the first. The outer mantle surface, -however, develops a number of calcareous granules which correspond to -a shell. The /Aplacophora/ are symmetrical, having the mouth and the -excretory opening at the anterior and posterior ends respectively. -The foot is greatly modified, being narrowed at times to a mere slit -along the ventral surface. Some of them have long, worm-like bodies. -This is no doubt a very primitive form of mollusk, or, if not a -primitive form, it has greatly degenerated from some higher type. -They are supposed to be commensal in habit and live in the deeper -water offshore. - -The /Aplacophora/ are not littoral animals, and it is extremely -unlikely that one will ever encounter them upon the beach, unless, -possibly, after the severest of storms. We may therefore leave them -with this mere mention and proceed to the second class of mollusks, -the /Gasteropoda/. [pg324] - - -TABLE SHOWING THE CLASSIFICATION OF THE GASTEROPODS AND SCAPHOPODS -DESCRIBED IN THIS CHAPTER - - Phylum =MOLLUSCA= - - Class =GASTEROPODA= - - Order =OPISTHOBRANCHIATA= - - Suborder =TECTIBRANCHIATA= - - Families Genera Species - - BULLIDAE ^Bulla^ ^B. (Haminea) solitaria^ - ^B. occidentalis^ - ^B. nebulosa^ - - APLYSIIDAE ^Aplysia^ ^A. Wilcoxii^ - - Suborder =NUDIBRANCHIATA= - - DENDRONOTIDAE ^Dendronotus^ ^D. arborescens^ - - AEOLIDIDAE ^AEolis^ ^AE. papillosa^ - - DORIDIDAE ^Doris^ ^D. bilamellata^ - - Order =PROSOBRANCHIATA= - - Suborder =DIATOCARDIA= - - Families Genera Species - - ACMAEIDAE ^Acmaea^ ^A. testudinalis^ - ^A. testudinalis,^ - Var. ^alveus^ - ^A. mitra^ - ^A. patina^ - ^Lottia^ ^L. gigantea^ - - FISSURELLIDAE ^Fissurella^ ^F. alternata^ - ^F. barbadensis^ - ^F. (Glyphis) aspersa^ - ^Lucapina^ ^L. crenulata^ - - HALIOTIDAE ^Haliotis^ ^H. splendens^ - ^H. rufescens^ - ^H. cracherodii^ - - TROCHIDAE ^Margarita^ ^M. cinerea^ - ^M. helicina^ - ^M. undulata^ - - ^Calliostoma^ ^C. occidentale^ - ^C. jujubinum^ - ^C. annulatum^ - ^C. canaliculatum^ - ^C. costatum^ - - ^Chlorostoma^ ^C. funebrale^ - ^C. brunneum^ - - ^Trochiscus^ ^T. norrisi^ - ^Livona^ ^L. pica^ - - TURBINIDAE ^Turbo^ ^T. castaneus^ - Var. ^crenulatus^ - - NERITIDAE ^Nerita^ ^N. peleronta^ - ^N. tessellata^ - ^N. versicolor^ - - ^Neritina^ ^N. reclivata^ - ^N. viridis^ - - Suborder =MONOTOCARDIA= - - JANTHINIDAE ^Janthina^ ^J. fragilis^ - - SCALIDAE ^Scala^ ^S. lineata^ - ^S. multistriata^ - ^S. groenlandica^ - ^S. angulata^ - - NATICIDAE ^Polynices^ ^P. (Lunatia) heros^ - ^P. (Lunatia) triseriata^ - ^P. (Lunatia) lewisii^ - ^P. (Neverita) duplicata^ - ^P. (Neverita) recluziana^ - ^Natica^ ^N. clausa^ - ^N. canrena^ - ^Sigaretus^ ^S. perspectivus^ - - CAPULIDAE ^Crepidula^ ^C. fornicata^ - ^C. plana^ - ^C. aculeata^ - ^Crucibulum^ ^C. striatum^ - ^C. spinosum^ - - LITTORINIDAE ^Littorina^ ^L. litorea^ - ^L. rudis^ - ^L. palliata^ - ^L. irrorata^ - ^L. angulifera^ - ^L. scutulata^ - ^L. planaxis^ - ^Lacuna^ ^L. vincta^ - ^Tectarius^ ^T. muricatus^ - ^T. nodulosus^ - - CERITHIIDAE ^Cerithium^ ^C. floridanum^ - ^C. muscarum^ - ^C. minimum^ - ^Bittium^ ^B. nigrum^ - ^Cerithidea^ ^C. scalariformis^ - ^C. sacrata^ - - VERMETIDAE ^Vermicularia^ ^V. spirata^ - - STROMBIDAE ^Strombus^ ^S. pugilis^ - ^S. gigas^ - - CYPRAEIDAE ^Cypraea^ ^C. exanthema^ - ^C. spurca^ - ^C. spadacea^ - ^Trivia^ ^T. pediculus^ - ^T. quadripunctata^ - ^T. californica^ - ^T. solandri^ - - DOLIIDAE ^Dolium^ ^D. galea^ - ^D. perdix^ - ^Pyrula^ ^P. papyratia^ - - CASSIDIDAE ^Cassis^ ^C. tuberosa^ - ^C. cameo^ - ^C. testiculus^ - ^C. inflata^ - - Families Genera Species - - MURICIDAE Subfamily Muricinae - ^Murex^ ^M. rufus^ - ^M. pomum^ - ^Trophon^ ^T. clathratus^ - ^Urosalpinx^ ^U. cinerea^ - ^Eupleura^ ^E. caudata^ - ^Pteronotus^ ^P. festivus^ - ^Ocinebra^ ^O. poulsoni^ - ^O. lurida^ - ^O. interfossa^ - ^Cerostoma^ ^C. nuttallii^ - ^C. foliatum^ - MURICIDAE Subfamily Purpurinae - ^Purpura^ ^P. lapillus^ - ^P. patula^ - ^P. haemastoma^ - ^P. crispata^ - ^P. lima^ - ^P. saxicola^ - ^Monoceras^ ^M. lapilloides^ - ^M. engonatum^ - ^Chorus^ ^C. belcheri^ - - COLUMBELLIDAE ^Columbella^ ^C. mercatoria^ - ^C. (Anachis) avara^ - ^C. similis^ - ^C. (Astyris) lunata^ - ^C. (Amphissa) corrugata^ - ^C. (Astyris) gausapata^ - - NASSIDAE ^Nassa^ ^N. trivittata^ - ^N. obsoleta^ - ^N. vibex^ - ^N. fossata^ - ^N. perpinguis^ - ^N. tegula^ - ^N. mendica^ - BUCCINIDAE ^Buccinum^ ^B. undatum^ - ^Chrysodomus^ ^C. decemcostatus^ - ^Sipho^ ^S. Stimpsoni^ - ^S. pygmaeus^ - ^Siphonalia^ ^S. kellettii^ - ^Tritonidea^ ^T. tincta^ - - TURBINELLIDAE ^Fulgur^ ^F. carica^ - ^F. canaliculata^ - ^F. perversa^ - ^F. pyrum^ - ^Melongena^ ^M. corona^ - - FASCIOLARIIDAE ^Fasciolaria^ ^F. gigantea^ - ^F. tulipa^ - ^F. distans^ - - VOLUTIDAE ^Voluta^ ^V. junonia^ - - MARGINELLIDAE ^Marginella^ ^M. apicina^ - - OLIVIDAE ^Oliva^ ^O. literata^ - ^O. mutica^ - ^Olivella^ ^O. biplicata^ - ^O. boetica^ - - CONIDAE ^Conus^ ^C. floridanus^ - ^C. pealii^ - - CANCELLARIIDAE ^Cancellaria^ ^C. reticulata^ - - Class =SCAPHOPODA= - - DENTALIDAE ^Dentalium^ ^D. dentale^ - ^D. pretiosum^ - ^D. hexagonum^ - ^Entalis^ ^E. striolata^ - -[pg328] - - - - -CLASS =GASTEROPODA= - - -The class /Gasteropoda/ is the largest and most comprehensive -subdivision of the /Mollusca/, and within its wide range of families -many differing details of organization are to be found. As a class it -possesses all the most characteristic features of the phylum, though -it is frequently modified in a high degree. This class includes -all the univalve mollusks (except /Nautilus/ and /Dentalia/), such -as the snails, the whelks, and the host of spirally coiled land, -fresh-water, and marine shells. - -The gasteropod foot is, as has been remarked, primarily the same -as in our schematic mollusk--a flat, muscular disk caused by -the thickening of the ventral body-surface. The neck, head, and -tentacles are also quite the same, but considerable modification -of these organs will be found when we come to examine some -specimens. The mantle is always present, except in the nudibranch -or non-shell-bearing forms; but in few of the /Gasteropoda/ is the -mantle so regularly simple as in our ideal mollusk. - -Perhaps the most striking feature of the /Gasteropoda/, and -one that will at first surprise him who has in mind the simple -structure of the ideal mollusk, is the fact that they are always -asymmetrical--that is to say, a median line drawn longitudinally -through a gasteropod will not divide it into halves of similar -anatomical structure. - -The quality of symmetry is an important one throughout the lower -orders of animal life. In nearly all phyletic or class descriptions -the word "symmetry" occurs, and its exact meaning must be understood. -Take, for example, a human being; a median line drawn vertically -would divide him into two similar halves--upon each side would be -an eye, an arm, a leg, etc., of similar shape and construction. So -far at least as the external features [pg329] go, man is then a -symmetrical creature; likewise the vertebrates in general. Cases -of actual symmetry are found in the lobsters and crabs and in the -segmented worms. It is usual in describing mollusks broadly and in -general terms to call them symmetrical animals, yet here is the -largest class within the phylum, whose representatives are none of -them symmetrical. In the /Gasteropoda/ the mouth is anteriorly placed -in the head, just as in the ideal form, but the digestive tract, -after traversing the visceral cavity in the usual fashion, suddenly -turns forward and terminates in an excretory opening either on the -right or on the left side of the animal, just back of the head. The -various other orifices for the genital and renal glands are also -placed in this unexpected anterior position. The gills, or branchiae, -are to be found upon one side only, forward of the heart, and -differ somewhat in appearance from the plume-like processes of the -/Amphineura/. - -What, then, has become of the corresponding gill we should expect to -find on the other side? The symmetrical shape of the foot is not in -the least altered, but what has happened to cause this distortion of -the visceral portion of the animal? And, finally, will this torsion -of the body of the snail perhaps account for the spiral nature of the -shell? - -An evolutionary process is supposed to have taken place in mollusks, -which, if real, would no doubt account for these curious conditions -of torsion in the /Gasteropoda/; but the theory upon which this -process is based is altogether speculative, and is not fully -sustained by the facts in the case. Originally all mollusks are -presumed to have been symmetrical, and are assumed to have resembled -very much in form the schematic creature we have already described. -Now, for some reason, certain of the primitive mollusks, but not all -of them, began to develop a larger visceral mass, which, continuing -to enlarge throughout many generations, began finally to protrude -above and form a hump on the dorsal side of the animal. This hump, -containing the liver, a portion of the intestines, and the generative -glands, as it increased in bulk became so much elevated that it could -no longer maintain itself in an erect position over the body, but, -impelled by its own [pg330] weight, began to sag over to one side. -Such a process would of course tend to twist the digestive tract and -bring the excretory opening constantly farther forward on one side. -At the same time, this process would necessarily interfere, by the -weight of the overhanging viscera and the shell covering the mass, -with the development of the branchiae lying upon that side and now -crowded under the visceral mass. Thus, according to this theory, this -process has continued until, in the modern gasteropod, the digestive -tract has been bent upon itself and twisted from a straight course -into a curve of almost 180 deg., bringing the excretory opening near or -just over the head, where it empties into the mantle cavity; while -the original right gill, by the same movement, has been brought to a -position on the /left/ side of the head, forward of the heart, the -original left gill having been crowded out, eventually to atrophy and -disappear. The same torsion is found in the nerve-cords; the heart, -situated at about the pivotal position of this twisting process, -has turned about upon itself, leaving an auricle in front of the -ventricle, one auricle, like one of the gills, having been lost. The -mantle portion covering the visceral hump naturally continued to -secrete its shell, though always in conformity with the change, the -result being the familiar spiral form of the usual gasteropod shell. - -This theory may not be satisfactory, but the asymmetry of gasteropods -is a problem to be solved, and a more interesting line of biological -investigation could not be found. - -Let us now take a good example of a gasteropod and locate its various -organs; at the same time we may use the occasion to refer to more -important modifications of these organs which will be encountered -later in the various genera. The most available gasteropod on the -east coast of the United States for this purpose, is /Fulgur/, both -on account of its large size and its abundance. /Buccinum/ may be -used if the student is north of Cape Cod and therefore unable to -secure a good living specimen of /Fulgur/; the anatomical differences -between the two are slight. - -Note the siphon protruding forward from a notch in the shell. This -consists merely in an elongation of a fold of the mantle, which is -held in a manner to constitute a tube, through which [pg331] the -animal draws in water to supply the gills, lying just back of the -siphon and concealed under the mantle in the cavity already spoken -of as the mantle cavity. With the exception of that portion of the -mantle which constitutes the siphon, no part of its margin, it will -be observed, can be seen, the edge of the shell completely hiding it -from view. - -In some genera the siphon is exceedingly long--in fact, longer than -the body of the animal. In these cases the mollusk is generally fond -of burying itself in the sand and maintaining communication with -the world above only by means of this long, fleshy tube. In some -genera the siphon is protected by an elongation of the shell, as in -/Fasciolaria/ (Plate LXXVI). An extreme example of this is given in -the figure on page 343, which represents a species of /Murex/, where -the siphon is not only protected by the shell, but the shell itself -is further protected by the double row of sharp spines with which it -is beset. - -[Illustration: /Buccinum undatum/: /si/, siphon.] - -There are some genera which possess no siphons at all, in all of -which cases there is no notch in the shell opening, the aperture -being round, as in /Natica/ and in /Littorina/ (pages 368, 371). The -mollusks of this type make a fold in the forward part of the mantle -which serves as a siphon. Such a muscular folding in the mantle would -be technically called a /functional siphon/. - -On the posterior dorsal side of the foot is attached a horny plate, -of concentric structure about a central or subcentral point or -nucleus. This is called the /operculum/, and serves to close the -entrance of the shell when the animal is withdrawn, the object no -doubt being protective. The opercula vary to a great extent in the -different genera; in some cases they are calcareous, in others -cartilaginous. When the aperture of the shell is very large it often -happens that the operculum does not entirely close the opening, as -in /Fulgur/, but in /Buccinum/ it is a close fit. The operculum is -entirely wanting in the /Pulmonata/, one of the [pg332] large orders -of the /Gasteropoda/. The figures represent some of the commoner -types of opercula. - -[Illustration: Various forms of opercula. /Turbo/ (/Sarmaticus/). -/Turbo/ (/Callopoma/). /Livona./ /Ampullaria./ /Natica./ ] - -The opercula have been utilized a great deal in the classification -of the /Gasteropoda/, and especially in some groups that have become -terrestrial in habit. Often, when shell-characters utterly fail to -give a clue to the proper generic position of a new or rare mollusk, -the operculum may be relied upon to indicate it. - -[Illustration: Various forms of opercula. /Pyrula./ /Purpura./ -/Littorina./ /Aulopoma./ /Torinia./ /Neritopsis./ /Strombus./ -/Conus./] - - -TENTACLES - -Two tentacles project like fleshy horns from the sides of the head. -These are not retractile, as in the land-snails, and their office -appears to be that of sensory organs. In both /Fulgur/ and /Buccinum/ -the tentacles are comparatively short and stout, and have expanded -bases; in many other genera they are long and slender. Almost without -exception the /Gasteropoda/ possess tentacles. [pg333] - - -EYES - -In /Fulgur/ the eyes are situated near the bases and upon the outer -sides of the tentacles; in /Buccinum/ they are extremely small and -are mounted about midway between the bases and the tips of the -tentacles. This is the usual position for the eyes in the marine -/Gasteropoda/. Only in the pulmonates, or land-snails, are the eyes -placed at the summit of the tentacles. Sight does not appear to be -a very important sense in the gasteropods, although the eye in some -instances becomes a highly developed organ. A number of forms that -have the habit of burrowing deep into the sand or mud are quite -destitute of visual organs, and certain cave-dwelling land-shells -have entirely lost the sense of vision. - - -MOUTH AND PROBOSCIS - -The mouth will easily be seen in both /Fulgur/ and /Buccinum/. It is -a small slit with slightly thickened, fleshy lips, and is placed on -the lower forward portion of the head. In the case of both of these -genera the mouth is situated at the end of a proboscis. It will be -noted that /Fulgur/ has a comparatively long and stout proboscis, or -snout, which is not retractile. /Buccinum/ has a smaller one. It is -fairly safe to assume that all gasteropods that possess a proboscis -are carnivorous. This organ is greatly developed in some genera, -where it actually exceeds in length the rest of the animal. In such -instances, no doubt, the creature is enabled to reach the interior -portions of the shells of its victims and to devour every vestige -of their flesh, for the mouth is most conveniently placed just at -the end of this long, trunk-like organ. The genera which have no -proboscis are, almost without exception, vegetable feeders. - -We must now remove the animal from its shell. It is well to boil -it first, for this does away with the annoying mucous secretion -that is freely exuded by glands in the foot when the creature is -roughly handled. Alcoholic specimens are apt to be much contracted -and hardened, and are therefore less satisfactory as subjects for -anatomical study. If it is not convenient to boil the [pg334] -specimen, break away the shell with a hammer, using care not to -lacerate the soft, fleshy portion within; when this is accomplished, -wash the animal carefully to remove the slimy exudation. Note the -"visceral hump," which is spiral, and which formerly occupied the -upper-whorl portion of the shell. The thin skin covering it is the -mantle, which below is greatly thickened and free, lying about the -foot like a heavy fleshy flap. - - -MANTLE - -The mantle-edge in both of these examples is simple; that is to say, -it possesses no fringe of tentacles, nor is it supplemented by extra -processes, characters which mark many genera of marine /Gasteropoda/. -In /Fulgur/ and /Buccinum/ the mantle-edge does not protrude below -the edge of the shell; but in many genera, especially those which -possess smooth, glossy shells, like the cowries (/Cypraea/) and the -graceful /Oliva/, the mantle is proportionately very much larger. In -these two genera, when the animal is extended, as in crawling about -the sand, the mantle curves upward and incloses a large portion of -the shell itself. Indeed, in some genera the shell is almost entirely -concealed by this extension of the mantle (/Sigaretus/, /Natica/, -etc.). - -When the shell is removed, the folding of the mantle which -constitutes the siphon can be plainly seen. The office of the siphon -has already been referred to, also the fact that the presence of a -siphon in the gasteropod mollusk may always be determined by merely -glancing at the shell alone, for a notch at the base of the aperture -indicates the place through which the siphon passed. In /Buccinum/ -this is merely a notch, but in /Fulgur/ the siphonal canal of the -shell is much longer. Just why the long siphons of some mollusks -should be naked and exposed to danger, while others are so carefully -protected by elongated, portions of the shell, is a mystery, but -nature is full of such contradictions. - - -THE GASTEROPOD FOOT - -The foot is long, broad, and flat on the under side, like a disk. -The variations in the gasteropod foot are almost infinite. [pg335] -In some of the species it is amazingly large and powerful, as -in /Polynices/ (/Natica/), and in most of the forms which live -along sandy beaches. These are sometimes provided in front with a -wedge-shaped process called the /propodium/, which serves admirably -as a plow to push aside the heavy wet sand through which the animal -forces its way. In /Nassa/, which is so common all along our coasts, -the foot has two terminal appendages or points behind. - -[Illustration: /Sigaretus l[oe]vigatus/, showing excessive -development of the propodium (/pr./) and metapodium (/met./) in a -mollusk living in sand (the shell, which covers only the liver and -adjacent parts, has been removed): /l/, liver; /s. ap./, aperture of -proboscis, here deflected from the median line; /t/, /t/, tentacles; -/f/, foot.] - -[Illustration: /Oliva textilina/ showing how the front part of the -foot (/f/) is developed into a sort of fender, the propodium (/pr./): -/e/, /e/, eyes; /m. ap./, front appendage of mantle; /m. ap.'/, -hinder appendage of mantle, folded into the suture when the animal is -at rest; /si./, siphon; /t/, /t/, tentacles.] - -There is no single feature of mollusks more important than the foot, -for upon the many modifications of this organ the various molluscan -classes are founded. The name /Gasteropoda/ means "stomach-foot," -the latter organ being merely a thickening of [pg336] the ventral -surface of the animal, giving to the creature, when active, the -appearance of crawling upon its stomach. - -If a living gasteropod is placed in a jar of sea-water and left -undisturbed it will soon crawl up the side of the glass and thus -afford an excellent view of the extended under surface of its foot. -The majority of the gasteropods are lethargic and slow in movement, -but others will be found to be exceedingly lively and able to creep -up the sides of the jar and make their escape in a surprisingly short -time. Further modifications of the foot will be mentioned later. - - -THE MANTLE CAVITY - -Now let us place the animal with the foot below and the head facing -us. The spiral visceral hump will point back and away from the -observer. The mantle covering the visceral portion is thin and -translucent like an ordinary skin, but at the base of the visceral -mass the mantle suddenly thickens very greatly, and spreads over -the dorsal portion of the foot or the body like a cloak. The space -between the body and the loose-lying mantle is called the /mantle -cavity/, and within this area are to be found several important -external organs. To find these it is well to cut the mantle flap in -a straight line, beginning just back of the head and ending at the -point where the mantle is attached to the body. This will most easily -be done with scissors. Having thus divided the mantle in front, throw -back the two flaps. On the right-hand side (left of the animal), and -attached to the inner side of the mantle thus exposed, will be seen -the branchiae, or gills. - - -THE BRANCHIAE, OR GILLS - -They consist of a row of flattened filaments bound together at the -base like the leaves of a book. The blood is conveyed to these -gills by a large vein, and is then forced through the thinly walled -filaments, being thus brought into close contact with the water, to -which it releases its carbon dioxide, and from which it receives the -life-giving oxygen. In certain gasteropods there are two sets of -gills, one placed upon each side of the body [pg338] (as in the -ideal mollusk); but the presence of two sets of gills only indicates, -in these gasteropods, that the twisting process of the viscera, -already alluded to as so remarkable a feature of this class, has not -proceeded far enough to destroy the functional activity of one of the -gills. - -[Illustration: Anatomy of the internal organs of a female gasteropod, -viewed from the dorsal side. The roof of the mantle cavity has been -divided by a longitudinal incision and the flaps laid out, that on -the left bearing the ctenidium and osphradium, and that on the right -the rectum and terminal part of the oviduct. The muscular dorsal wall -of the body and the introvert have been divided so as to bring into -view the anterior part of the alimentary canal and a portion of the -nervous system. The buccal cavity has been tilted up and opened so -as to show the odontophore, and the esophagus has been cut through -near the anterior end. A portion of the ventral wall of the crop -has been removed so as to bring the internal folds into view, and -the interior of the nephridium with the contained portion of the -intestine has been exposed. The stomach is not seen, being hidden by -the nephridium, and the ovary is not represented. /an./, anus; /ant. -aort./, anterior aorta; /aur./, auricle; /buc./, buccal cavity; /cer. -buc. con./, cerebro-buccal connective; /cer. g./, cerebral ganglia; -/crop/, crop; /cten./, ctenidium; /int./, intestine; /jaw/, jaw; -/l. buc. g./, left buccal ganglion; /l. sal. gl./, left salivary -gland; /neph./, nephridium; /neph. ap./, nephridial aperture; /od./, -odontophore; /oes./, esophagus; /oes'./, anterior end of same, cut -and turned aside; /osph./, osphradium; /ovid./, oviduct; /ovid'./, -terminal thick-walled portion of oviduct; /pleur. g./, pleural -ganglion; /post. aort./, posterior aorta; /post. oes./, posterior -esophagus; /rad. s./, radula sac; /r. sal. gl./, right salivary -gland; /rect./, rectum; /sal. du./, salivary duct; /siph./, siphon; -/supra. g./, supra-esophageal visceral ganglion; /tent./, tentacle; -/vent./, ventricle.] - -In general, it may be said that the breathing process of mollusks -does not markedly differ from the respiratory methods of higher -forms of animals. Whether the breathing is effected by gills or by -a pulmonary sac, the essential features of the system are the same -as in fishes or mammals. There are, however, some rather peculiar -developments in the breathing system of gasteropods that are worthy -of notice. The gills themselves differ throughout the various orders -of this class both as to their structure and their relative position; -in one of the orders (the /Pulmonata/) the gills have entirely -disappeared, and are replaced by a pulmonary sac which fulfils the -purpose of a lung. - -It is a generally accepted theory that all land or air-breathing -mollusks were originally marine, but by a gradual change in their -habits have developed into terrestrial forms, losing their gills -and acquiring in their place organs which correspond to lungs. The -theory is supported by the fact that many species of marine mollusks -live between tide-marks, and for several hours daily are obliged to -maintain life outside of their native element. The /Littorinidae/, -which may always be found in abundance on both the east and the west -American coasts, usually live high above low-tide line, and some -tropical species of this genus actually live in the trees above -the reach of high tide. They have gills just as in /Buccinum/ or -/Fulgur/, but the /Littorina/ shell is strongly suggestive of certain -land forms, and there is reason to believe that the genus is in -course of evolution into a pulmonate. On the other hand, there are to -be found in fresh water numerous genera which are true pulmonates, -and which are obliged to come to the surface every few minutes to -obtain air. One notable genus of marine gasteropods possesses both -lungs and gills, and one marine form has entirely lost its gills -and breathes only by means of lungs. It is quite likely that all -mollusks are able to breathe more or less all along the exposed -mantle surface, which is usually [pg339] crowded with capillaries -with exceedingly thin walls. This very remarkable method of surface -respiration is proved to exist in the nudibranch or shell-less marine -/Gasteropoda/, for they possess neither gills nor lungs. - - -OSPHRADIUM - -Lying just under the gills, and side by side with them, is a smaller, -plume-like organ having the appearance of a smaller gill; it is -called the /osphradium/. The office of this organ is not definitely -known, but the supposition is that it is the seat of the olfactory -nerves. The osphradia are not always present, but whenever found they -are placed in close conjunction with the gills, in order, probably, -that the animal may best determine the quality of the water brought -by the siphon to the breathing-organs. In /Buccinum/ the osphradium -is especially prominent. In all mollusks the sense of smell is highly -developed. A dead animal anchored to the bottom will very soon -attract the carnivorous /Mollusca/ from every direction. This is not -a bad way to trap certain species that live upon rocky stations and -are otherwise difficult to secure by the dredge. - -On the left-hand side (right of the animal), and adhering to the -under side of the mantle flap, which has been thrown back, a somewhat -inflated and convoluted tube, the rectum, will be seen. It terminates -in an opening just within the mantle-edge. By the side of this are -the renal and genital openings. - - * * * * * - -Having now examined the external organs, we may investigate the -internal anatomy of our subject. To do this thoroughly requires -considerable skill, but for the purpose of merely discovering the -relative positions of the principal internal organs a little care -only is necessary. The work will be greatly facilitated by boiling -the animal for a few minutes, for this serves to harden the tissues -and to separate the various organs in a most satisfactory manner. - -To begin, open the proboscis from the mouth, cutting back so as to -expose the esophagus. It will be seen that the throat is long and -very muscular. [pg340] - - -RADULA - -Hidden among the red stripes of muscular fiber which line the inner -surface of the throat will be found a fleshy strip covered upon -one side with many transverse rows of chitinous teeth. This is the -/lingual ribbon/, or /radula/. Remove as much of it as possible, and -examine it with a hand-glass. The radula is a most important organ, -and is a unique possession of /Mollusca/, except the pelecypods, or -bivalves. Usually it lies coiled up like a spiral when not in use; -its purpose is to tear and rasp food. - -[Illustration: Three rows of teeth from the radula of /Fasciolaria -trapezium/.] - -[Illustration: Portion of the radula of /Imbricaria marmorata/.] - -The radula has been the subject of much study by conchologists, and -has furnished the basis for an arrangement of the numerous sections -of gasteropods into somewhat well-defined groups. If the observer has -a strong glass he will notice that each transverse row of teeth on -the ribbon consists of a median or central tooth with several points -or "cusps." /Fulgur/ has a median tooth with three cusps; /Buccinum/ -one with six. On each side of the median tooth is a lateral tooth, -which in /Fulgur/ will be seen to have six cusps, and in /Buccinum/ -five. In many patterns of radulae there is, besides the median and -lateral teeth, still another paired row, called the marginals. In -the accompanying figures are given some examples which show small -sections of lingual ribbons. While all the radulae of mollusks are -capable of being grouped by their general characteristics, yet in no -two species of mollusks are the radulae quite identical. [pg341] - - -VITAL ORGANS, STOMACH, LIVER, RENAL GLANDS, ETC. - -The digestive tract will be found to widen out a short distance back -into a crop or stomach, and, continuing still further, to lose itself -in a soft, brownish mass within the coiled spire, which is the liver. -The very large size of the liver leads one to suspect that /Fulgur/ -and /Buccinum/ must be voracious creatures to need so large an organ -for the secretion of bile. In many species of mollusks the stomach -and intestines are filled quite solidly, at times, with a gelatinous -transparent substance called the /crystalline stylet/. Just why the -digestive tract should be clogged with this substance no one has -yet been able to explain, so here again is a chance for original -investigation. The intestine curves about after reaching the liver, -and comes forward again to appear once more as the rectum, clinging -to the inner surface of the free portion of the mantle. - -Closely associated with the liver, but differing slightly in color, -is the gonad, or organ in which the genital products are formed. -Situated dorsally and forward of the liver and gonad is a large renal -gland, which may readily be detected by its peculiar structure. In -some forms the kidney is closely associated with the gonad, and seems -to cooeperate with the latter in the generative functions. - - -HEART AND VASCULAR SYSTEM - -To find the heart, make an incision into the body just at the -posterior end of the gills. The heart is white and round, and -is inclosed within a cavity known as the /pericardium/; it has -a ventricle and one or two auricles, although in /Buccinum/ and -/Fulgur/ there is but one auricle. - -There is nothing remarkable about the vascular system to distinguish -it from that of many higher forms of animals. It is, however, not -completely closed--by which is meant that the blood is not always -contained within arteries or veins, and that it does sometimes flow -into other organs and floods certain other body-cavities, although -the vascular system of mollusks is by no means so completely open as -is that of insects and crustaceans. [pg342] - -Having examined the animal which inhabits the shell and gained an -idea of its anatomy, we may now turn to an inspection of the house -which it has built for itself, and here we shall find a delightful -subject for study. - - -THE GASTEROPOD SHELL - -An industrious hour of collecting upon almost any beach will provide -the student with an abundance of interesting shells. Putting aside -the bivalves, the univalve or gasteropod shells remaining should be -closely examined for the purpose of becoming acquainted with their -various conchological features. The collector will see at once that -he has a number of species that differ more or less widely in their -general form, size, texture, and sculpture. Some shells will be long -in proportion to their width, with many turns of the spire which -probably terminates in a sharply pointed apex; others will be almost -round, with comparatively few spiral turns which end in a blunt apex, -giving to the specimen outlines suggestive of a dome. A wide range of -characters will be found in the mouths or apertures of the shells, -some being almost if not quite round, others oblong and with a notch -cut into the lower portion of the opening, and others possibly with -this notch extended into a sort of semi-inclosed channel. A first -lesson in classification of the /Mollusca/ may be taken by dividing -the results of the first day's collecting of univalve shells into -groups according to these prominent shell-characters. - -[Illustration: Parts of a gasteropod shell: /a/, anterior canal; /b/, -body-whorl; /c/, columella; /l/, outer lip; /m/, mouth or aperture; -/p/, posterior canal; /s/, sutures; /sp/, spire; /u/, umbilicus.] - -A good knowledge of the parts of a gasteropod shell is essential to -the student, and it can readily be acquired. Four specimens are given -in the accompanying figures, representing highly divergent [pg343] -types of marine gasteropods, and their respective characteristics may -be noted by comparing them one with another: /Fasciolaria tulipa/ -(Plate LXXVI.), a Floridian shell; /Polynices heros/, a common -species found on all the sandy shores of the American Atlantic -coast; /Murex tenuispina/, an Indo-Pacific species much prized by -collectors; and /Acmaea testudinalis/, commonly found in Maine and -Massachusetts at low tide clinging to rocks. - -[Illustration: /Polynices heros/; /Acmaea testudinalis/, from below; -/Acmaea testudinalis/, profile; /Murex tenuispina/.] - -The extreme top of the shell is called the /apex/, and it may be -either sharply pointed or obtuse. Each turn is called a /whorl/; the -last one, and always the largest, is called the /body-whorl/, the -others collectively forming the /spire/ of the shell. When the animal -first emerges from the egg it is always provided with one or two -whorls, which generally may be distinguished at the apex as smoother -than the rest of the spire, and a faint line may be discovered where -the shell began its growth after birth. These [pg344] first whorls -of embryonic growth are usually referred to as the /nepionic whorls/. -The interstices between the successive whorls are called /sutures/, -and these lines of juncture may be shallow or deep according to the -convexity of the whorls. The sculpturing of the whorls is often -of great complexity, and exhibits /nodules/, /varices/, /ribs/, -/revolving striae/, /spinous processes/, and /lines of growth/. -It frequently happens that there is a complete absence of any -sculpturing whatever, the whole surface of the shell being perfectly -smooth, save for the faint lines of growth to be detected only under -a magnifying-glass. The outer edge of the mouth or aperture of the -shell is called the /outer lip/. This may be more or less thickened, -expanded, or simple. The inner lip is called the /columella/, and may -be greatly extended anteriorly. When the mouth of the shell is round, -and there is no notch or indentation either above or below, it is -said to be /continuous/. - -The /anterior canal/ is for the accommodation of the siphon of the -animal, which, as noted above, may be very long or almost entirely -absent; therefore the character of the shell generally indicates -whether or not the animal itself possesses a long siphon. There is in -some forms a notch at the upper extremity of the mouth, which is for -the accommodation of the anal discharges. When present it is called -the /posterior canal/. - -It will be noted that all the specimens figured as examples, save -one, are spiral, the coils revolving about an imaginary axis. When -the whorls are not too closely coiled there is left open to the view -a hollow space throughout the entire length of the shell, which is -called the /umbilicus/. When the coils of the shell are very compact -there is no umbilicus to be seen. The umbilical opening may be very -large, giving a clear view of the inner surfaces of all the whorls -right through to the apex. The usual gasteropod shell is in reality a -hollow tube wound about an imaginary axis. Since the tube increases -in size as it progresses, the base of the shell is necessarily -wider and larger than the apex. Thus all gasteropod shells may be -reduced in shape to the single type of a cone or top, modified by -the excessive length or shortness of the spire, or otherwise altered -by special peculiarities. In /Polynices duplicata/ (page 368), it -will be observed that while the [pg345] umbilicus is fairly large, -its external opening, in the adult shell, has been almost completely -closed by a callous process thrown off from the inner or columellar -lip. - -Gasteropod shells may be /sinistral/ or /dextral/, according as -the whorls turn to the left or right. The great majority of marine -species are dextral, having the opening on the right, although a -few species exhibit the curious property of being constructed upon -either the one or the other plan without apparent reason. Sinistral -specimens of many normally dextral species have been discovered, but -they are so rare as to warrant the belief that such specimens are -merely deformities or monstrosities resulting from some accident of -birth. - -The collector will soon learn to distinguish between young and adult -specimens, for those finishing touches of wonder and beauty which -the mollusk gives to his protective covering are made only by the -adult. The outer lip of young gasteropod shells is usually thin and -fragile; even if slightly thickened, it has an unformed or unfinished -appearance. - -Shells differ greatly in their /structure/, many species being -porcelanous like china, others glassy, and many more are of a softer -chalky composition. In the latter case the shell is usually covered -with a thick membranous skin, which, when removed, leaves a dull, -lusterless, white body beneath. Shells of this texture, when cast -upon the beach, soon yield to the weathering action of sun and air. -The porcelanous shells are composed of successive layers of carbonate -of lime, throughout which is a filmy membranous framework of a -substance similar to that of which the covering of the /Crustacea/ is -formed. The mode of deposition of the various layers of crystalline -calcic carbonate and the peculiar lineation of their outer surfaces -give rise to the iridescent or nacreous appearance of some shells. - -With the exception of those species in which the mantle of the -animal is extended over the edge of the aperture and more or less -envelops the entire test, there is an outer skin of membranous or -organic matter which overlies the surface of the shell. This skin -is sometimes quite thick, often hairy, and is usually of a dull -greenish- or brownish-yellow color. In many genera this [pg346] -outer covering of the shell is excessively thin. In old specimens -the epidermis is usually worn away from the apical whorls. It often -happens that the shells of the most exquisite colors and markings are -thus rendered somber and unattractive by their tenants during life; -when the animal dies, or when such specimens are kept in a cabinet -for a period of time, the epidermis dries, cracks, and falls off, -revealing the wealth of color and design beneath. - -The growth of the gasteropod shell is accomplished by the exudation -from the margin of the animal's mantle of a liquid containing the -shelly matter in solution. The mantle-edge is provided with a -complicated system of glands and pores, from which is secreted this -"stony liquor." This more or less viscous liquid, containing the -carbonate of lime and the other inorganic materials of which the -shell is composed, hardens upon exposure, and the shelly matter is -then deposited in crystalline form around the edges or lip of the -shell aperture. The gasteropod shell therefore grows by the continual -building out of its aperture through successive depositions of shelly -matter at the extreme edge of the lip. At the extreme edge of the -mantle margin are situated those glands which secrete the materials -for the epidermis of the shell, and as one would therefore expect, -this outermost layer of epidermis is first produced in the advancing -growth of the shell. There also are situated the pigment-glands, -which produce the color-secretions. The various layers of the shelly -substance are successively deposited inside the mouth of the shell by -glands situated just back of the extreme edge of the mantle margin. -Thus in the growth stage, if one could examine closely the aperture -of a gasteropod shell, one would observe at the extreme tip of the -lip this projecting epidermis, just beneath it and just inside the -aperture a thin deposit of shelly matter, just beneath this, and -farther in, another layer, and still farther in a third layer. - -The growth of nearly all gasteropod shells is marked by periods of -rest. During the inactive seasons the creature may thicken the edge -of the aperture to a greater or less extent by an extra deposit of -shelly matter, for otherwise the thin lip might soon be [pg347] -injured or broken. These places where the lip was thickened, as a -temporary protection until the young animal decided to continue -building, appear on the surface of adult shells, and persist as -/varices/, "raised lines of growth," "longitudinal ribs," etc. Such -forms of sculptural markings generally occur at equidistant points -and preserve a scheme of regularity which would indicate that the -periods of rest were of seasonal occurrence. All irregularities and -all surface features of the external shell simply reflect certain -peculiarities of the mantle margin of the animal; all spinous -processes, for instance, as in the marvelous /Murex tenuispina/, -indicate the existence of finger-like processes extending from the -mantle margin, which once occupied the hollow thorns projecting -from the shell. When the outer surface of a shell is devoid of -any sculpturing and is perfectly smooth, one may assume that the -mantle margin of the animal was simple. If the edge of the lip has -a crenulated appearance and the surface of the whorls is decorated -with revolving ribs, the mantle margin was probably folded or wavy. -There can be no doubt but that the entire mantle surface is provided -to some extent with glands for the secretion of shelly matter, for -if any portion of the shell is accidentally injured the animal soon -repairs the break with a calcareous deposit. But such repairs are -never homogeneous in texture with the other parts of the shell of -normal growth; the patches are never covered externally with an -epidermis, and they are always devoid of color. The function of the -epidermis is to protect the calcareous shell from the corroding -agents contained in sea-water. Hence it is that, when the epidermis -is removed, "dead shells" exposed to the influence of the water -or the weather soon lose their brilliancy and luster, and become -undesirable for specimens either for the cabinet or for study. It -often happens that living shells, inhabiting a region where, for one -cause or another, the water is highly charged with impurities of an -acid nature, are discovered to be badly corroded about the apex, -where the epidermis is thin and likely to be rubbed off. For this -reason specimens collected in harbors near large cities or near the -mouths of rivers are apt to be poor and defective. - -The inner surface of all shells, if not actually nacreous, is -[pg348] always perfectly smooth. When foreign substances, such as -grains of sand, enter the shell and cannot be removed by the animal, -the irritation caused thereby to the soft, fleshy creature induces -discharges of a liquid from the glandular surface of the mantle, -which hardens about the offending substance and glazes it over with a -smooth, pearly deposit. - -/Acmaea testudinalis/ (page 343) presents a special type of gasteropod -shell which is found in several families. Here the spire seems to -be wholly absent, and the entire shell consists of but one large -body-whorl. There are very many of these patelliform species, -inhabiting many seas and belonging to many different genera, and -in nearly all cases their embryonic shells display a spiral form. -After birth the animal does not build his house upon the spiral -plan, but expands the shell into one large shield-like covering. -The student, however, must not presume that /Acmaea/ is an ancestral -type just because the simple character of the shell is suggestive -of the model chosen to represent a schematic mollusk; anatomically -/Acmaea/ presents the complications of body-torsion which show a very -considerable evolutionary change, and indicate that its simple shell -is probably a degenerate form of a once more highly developed and -convoluted one. - -The forms, the architecture, and the painting of gasteropod shells -are so infinite in variety that it would be unwise to attempt a -description of their marvels. A close observer of nature's works -soon becomes prepared for every surprise, but he never ceases to be -charmed and fascinated by his new discoveries. The careful student -alone can learn really to see and appreciate the wonders of nature, -and this is especially true in the study of the /Mollusca/. - - -CLASSIFICATION OF GASTEROPODS - -The /Gasteropoda/ far exceed all the other divisions of the -/Mollusca/ in the number of their genera and species. Apparently -this has not always been the case. There is evidence tending to show -that in past geological epochs the pelecypods (the bivalve shells) -outnumbered the gasteropods, but that in the course of time the -increase in the genera of gasteropods has been more [pg349] rapid. -To judge also from the very large number of extinct families among -the cephalopods, which once flourished in astonishing abundance, it -would appear that they are a dying race. - -The classification of the /Gasteropoda/ is primarily a division into -three great orders: the /Opisthobranchiata/, the /Prosobranchiata/, -and the /Pulmonata/. The /Pulmonata/, which include the land and -fresh-water gasteropod shells, are characterized by the presence of -a breathing-sac, or lung, instead of gills. They are, therefore, -essentially air-breathers, and would perish if kept too long under -water. The /Opisthobranchiata/ and /Prosobranchiata/ are marine, -and, like all animals which breathe by means of gills, soon die -when removed from the water. We have already noted, however, how -some genera of marine gasteropods that find their station about -high-tide mark are able to live for considerable periods out of the -water, notwithstanding the fact that they are fully equipped with -gills and not possessed of lungs. Indeed, there is one large family -of prosobranchs (the /Cyclostomatidae/) that has become entirely -terrestrial in habit, its members having lost their gills and -acquired lungs, but their organization otherwise is so essentially -that of the prosobranchs that they have never been considered as -pulmonates. - -The main difference between these two orders of marine gasteropods -is that in the prosobranchs the breathing-organs (the gills) are -placed in a position forward of the heart, and the degree of torsion -(page 330) characteristic of this molluscan class has been continued -until the auricle of the heart is in front of the ventricle. There -is always a shell, usually spiral, and, with few exceptions, an -operculum. In the opisthobranchs, on the other hand, the relative -position of the heart and gills is reversed, and they further differ -from the prosobranchs in that the sexes are always united in each -individual. The opisthobranchs are not always provided with a shell. -One division of the order, known as the "nudibranchs," are entirely -naked. These are commonly called the "sea-slugs," and are to be -found crawling about the marine vegetation in shallow water, in -tide-pools, and on the piling of old docks. Curiously enough, the -sea-slugs (see page 354) have no gills at all, but, having lost these -apparently essential organs, are [pg350] enabled to "breathe water" -through their skin. They are wonderfully beautiful creatures, and the -collector must not fail to secure some specimens, put them into a jar -of sea-water, and watch them expand. - -There are other more superficial differences between the prosobranchs -and the opisthobranchs, which will enable even a beginner to -distinguish them at a glance. When the latter are possessed of an -external shell, it is bulbous, generally glassy, and with a simple -lip, the aperture extending the entire length of the shell. Again, -the mantle or the propodium of the foot is greatly extended and -usually covers the shell almost wholly. - -With the exception of the nudibranchs, which are common all along -the Atlantic shore, especially north of Cape Cod, there are very few -opisthobranchs to be found in American waters. Their shells are not -very abundantly found anywhere, though in Florida there are two or -three species which an untrained collector might discover. - -Practically all the gasteropod or univalve shells that will be taken -by the ordinarily expert collector along the shore are prosobranchs. -This order includes the great majority of marine gasteropods, and -is entitled to the distinction of claiming, in the great number of -its genera and species, the most startling eccentricities of form -and color to be found among the /Mollusca/, if not among all marine -invertebrates. - -Only those species which are actually abundant on the Atlantic and -Pacific shores of the United States, and which are likely to be found -by the untrained collector, are selected from the long list of forms -which belong to the three faunal regions involved. - - -ORDER =OPISTHOBRANCHIATA= - - -SUBORDER ~TECTIBRANCHIATA~ - -To avoid confusion, it is well to keep the systematic table in view: - - Class Orders Suborders - - =GASTEROPODA= =OPISTHOBRANCHIATA= =TECTIBRANCHIATA= - =NUDIBRANCHIATA= - =PROSOBRANCHIATA= - =PULMONATA= - - -[Illustration: PLATE LXV. Bulla occidentalis, enlarged. Bulla -nebulosa. Lottia gigantea, inside view. Fissurella alternata.] - -As has already been remarked, shell-bearing opisthobranchs are not -abundantly represented in number of species in North American waters. -South of Cape Cod, in muddy bays and well-sheltered places, the -little shell, /Haminea solitaria/, may, however, often be found in -considerable numbers. - - -GENUS ^Haminea^ - - ^H. solitaria.^ Like all external opisthobranch tests, the shell of - this species is thin and fragile, and would appear to be of small - importance to the creature it only partially protects. It is devoid - of spire, is shining bluish-white, sometimes brownish in color, - and is marked with revolving grooves, which, being cut across by - irregular growth-lines, give its surface a faintly decussated - appearance. The aperture is as long as the shell; the columella is - incurved. This little species is especially abundant in shallow - water about Vineyard Sound and in Peconic Bay. - -[Illustration: /Haminea solitaria./] - - -GENUS ^Bulla^ - - ^B. occidentalis.^ This species, which is found in the waters - of Florida on all sandy beaches, is a relative of the Northern - species just described. The shell is larger than that of /Haminea - solitaria/, and has a color-pattern of mottled or clouded - reddish-brown on a white foundation. There is no spire; there - is a pit in place of an apex; and the aperture extends the full - length of the shell. To the naked eye the surface appears smooth - and shining. It is an exceedingly variable species, occurring all - through the West Indies, but not north of Florida. The shores of - the keys along the west coast of Florida are often strewn with - these shells after storms. The animal, like all the shell-bearing - opisthobranchs, is very large as compared with the shell, and the - large mantle folds recurve upward, almost completely hiding the - shell from view. (Plate LXV.) - - ^B. nebulosa.^ This is one of the largest and finest species of - the family /Bullidae/. It is found on the coast of California south - of San Francisco. The shell is much larger than that of either of - the Atlantic species mentioned above, but very closely resembles - them in outline, although it is built upon a more generous plan - and is more richly painted. It is brownish, mottled with white and - yellow patches, and is very suggestive of certain kinds of birds' - eggs. The animals have a greatly extended mantle which almost - completely envelops the shell. The foot is extremely large, with - great wing-like developments upon each side, called parapodia. Some - species of /Bulla/ have been seen to swim by means of the lazy - flapping of the parapodia. (Plate LXV.) - - -SEA-HARES - -Closely allied to these outer-shell-bearing opisthobranchs is a large -and important group of tectibranchs, known as [pg351] "sea-hares." -They have a mantle so greatly developed that it actually covers the -shell, and its edges unite and fuse over the top. The shell, in -consequence, having almost ceased to be of use as a protection, has -degenerated into a mere horny plate, and has lost all resemblance to -the ordinary gasteropod shell. Having practically lost its protective -office and become a mere internal plate, it is quite probable that -it will in time wholly disappear. The gills of the sea-hares are -concealed under a flap of the mantle, their position being posterior -to the heart. The most conspicuous representative of this type of -tectibranchs in the United States is the following: - - -GENUS ^Aplysia^ - - ^A. Wilcoxii.^ This species appears at times in vast numbers in - the waters of Florida, until the sea may truly be said to be - fairly alive with them. They swim lazily with a waving motion of - the parapodia. They disappear as mysteriously as they come, and - for months not a specimen will be seen. There is a variety of this - Floridian /Aplysia/ which occurs at Cape May, but no sea-hares are - to be found north of that point. The tropical Pacific furnishes an - astonishing wealth of these creatures, belonging to many genera - and species, and among them are some of the most beautiful of the - invertebrate animals. - - -SUBORDER ~NUDIBRANCHIATA~ - -The opisthobranchs are divided into two suborders, the second of -which is called /Nudibranchiata/. The name is well chosen and -very suggestive, for it means "naked or exposed gills"; but this -anatomical feature is only one of the peculiarities of this suborder. -The nudibranchs are commonly known as "sea-slugs"; for, like the -land-slugs, which are also true mollusks, they possess no shell at -all. That they at one time carried a shell is evident from the fact -that they are born with a rudimentary testaceous covering, which soon -afterward disappears. - -A striking peculiarity of the nudibranchs is that the conventional -molluscan mantle is not usually apparent. Instead of seeing the usual -flaps or folds of the mantle which more or less encircle mollusks, -and which one seems to have a right to expect, [pg352] they are -entirely absent, and the body of the sea-slug assumes in consequence -a worm-like appearance. Other notable features of the nudibranchs -are the great number of tentacular processes that usually project -from the dorsal region of the animal, and, in many of the genera, an -entire absence of gills. When the gills are present, as is the case -in several of the nudibranch families, they are not placed along the -side of the animal, where one would naturally look for them, but are -arranged in the form of a rosette of plume-like processes situated in -the posterior dorsal region, or, in other words, on the animal's back. - -Nudibranchs are commonly to be found all along the Atlantic and -Pacific coasts of North America, and more especially in the colder -waters north of Cape Cod. They are essentially littoral, and live -upon algae in shallow water, upon eel-grass in sheltered places, -and in tide-pools, where there is more or less vegetation. They -crawl about the fronds of algae, or swim, foot upward, with a gentle -and undulating motion, or, when caught between tides, may be seen -clinging to the under surface of rocks. Protective resemblances -have been so remarkably developed in the nudibranchs that they are -not always easy to discover; indeed, one may actually be looking at -one for some time without suspecting it to be other than some torn -fragment of seaweed. - - * * * * * - -There are many species belonging to several genera which frequent -the Maine and Massachusetts coasts, but those most likely to be -encountered are the following: - - -GENUS ^Dendronotus^ - - ^D. arborescens.^ This species is about one inch long and variable - in color, but is usually reddish-brown or rose. There are no - tentacles, but in their place are two antler-like appendages - pointing forward and branched like a tree. All along the back are - two rows of these curiously branched processes, which give to - the animal the appearance of a plant. These /cerata/, or dorsal - papillae, are delicately transparent, contractile, and richly - colored. The function of these papillae is not fully known. As - the animal has no specialized breathing-organs, it is reasonable - to suppose that respiration is carried on through the outer skin - and perhaps all over the surface of these branched papillae. The - liver, which [pg354] in most nudibranchs is extremely large and - completely surrounds the stomach, in /Dendronotus/ also extends - into these dorsal cerata, so that they may have some sort of - digestive function. - -[Illustration: /Dendronotus arborescens./] - - -GENUS ^AEolis^ - - ^AE. papillosa.^ This is probably the commonest nudibranch upon - the North Atlantic coast, and it occurs as frequently in European - waters. It may readily be found clinging to stones, algae, the - piling of wharves, eel-grass, etc., in bays or in rocky tide-pools. - The color is yellowish-gray to orange, with purplish or olive - spots. The cerata are very numerous, and cover the dorsal portion - of the animal save for an open space along the middle of the back. - There are two sets of tentacles, the two dorsal and the two simple - labial tentacles. The foot tapers behind to a sharp point, and is - truncate in front. As in /Dendronotus/, the liver is diffused into - the cerata, which in /AEolis/ are simple tubular processes without - the branching character of those of the former. Both species lay - their eggs in a gelatinous, bobbin-like cord, which is hung in - festoons over rocks or upon zooephytes, or at times they wind the - cord in a coil upon the surfaces of stones. When the young first - hatch out, they are provided with a glassy nautiloid shell, a fact - which would indicate that at some remote period they were, like - most mollusks, provided with a shell. /AEolis/ swims in an inverted - position, and is at times exceedingly active. It is very variable - in coloring and in the number of cerata. - -[Illustration: /AEolis papillosa./] - - -GENUS ^Doris^ - - ^D. bilamellata.^ In /Doris/ we find a quite different type of - nudibranch from that presented by the two genera /Dendronotus/ - and /AEolis/. In one there were numerous branched cerata or dorsal - papillae, in the other many plain cerata, and in neither case were - there any specialized [pg355] breathing-organs. In /Doris/, - however, there are no dorsal papillae at all, the back being covered - with calcareous spicules, which form a sort of secondary shell. - There is a circlet, or rosette, of retractile plume-like gills, or - branchiae, placed in the middle of the back posteriorly. There are - various species of /Doris/, and of closely allied genera belonging - to the family /Dorididae/, which are to be found along the New - England coast in tide-pools and among rocks. Those seen by the - writer never appeared to be other than very sluggish creatures, and - proved to be rather unsatisfactory tenants of the aquarium. - -[Illustration: /Doris bilamellata./] - -When discovered at low tide upon moist seaweed or stones, or when -disturbed in the water, nudibranchs often appear like small lumps of -jelly-like tissue, without a single attractive feature. It is only -when they are placed in a jar of sea-water and left unmolested for -a few moments that they unfold their beauties to the view. On the -Pacific coast there are numerous species of nudibranchs, occupying -corresponding shore stations and exhibiting the same degree of high -coloration. There are over a thousand species of sea-slugs scattered -about the various seas. They find their greatest development in -tropical waters, and for brilliancy of tint and variation in form -are unequaled by any other class of animal life, save perhaps the -butterflies. - - -ORDER =PROSOBRANCHIATA= - -To this exceedingly large and comprehensive order of gasteropods -belong the great majority of univalve mollusks. In point of number of -genera and species and in abundance of individuals, the prosobranchs -probably exceed all the other orders of mollusks combined. They may -be called the typical gasteropods, the shell being univalvular and -generally spiral, and the animal exhibiting the singular torsion -of the visceral mass which has placed the breathing-organs forward -of the heart. They are provided with an operculum (placed upon the -posterior dorsal portion of the foot), which is used to close the -aperture of the shell against [pg356] enemies when the animal -retires within its fortress. They are all marine except a very -few families, which, supposedly of marine derivation, have become -terrestrial in habit. - -The prosobranchs are further subdivided into suborders according to -certain peculiarities of the heart and breathing-organs. There is -a group of these prosobranchs which gives evidence of an inferior -degree of that visceral torsion which is always found in the -gasteropods. In this group, or suborder, the heart has two auricles, -and there is a pair of gills instead of only a single one. Other -internal organs are paired just as they were represented to be in -the schematic mollusk. This group also seems to show its primitive -character in the want of a proboscis and a siphon, or, in some -families, by having the ventricle of the heart traversed by the -intestinal canal, just as in the lower class of mollusks, which -includes the clams and oysters. For the most part the shells of this -group are not typically spiral, but are patelliform, shield-like -coverings, with only a suggestion of a spiral form at the very tip -of the apex. This group of primitive prosobranchs is included in the -following suborder: - - -SUBORDER ~DIATOCARDIA~ - -This suborder is named from the presence of two auricles in the heart. - - -FAMILY ~ACMAEIDAE~ - -The first family to be noted is the /Acmaeidae/. Its principal genus, -/Acmaea/, is well represented on both the east and the west coast of -the United States. - - -GENUS ^Acmaea^ - - ^A. testudinalis.^ This species is found in vast numbers all along - the New England shore, clinging to the rocks between tides. They - are usually called limpets. The shell is solid, conical, with an - oval outline, and with no trace of a spiral form in the adult. When - the shell is thoroughly cleaned, it generally presents a mottled - coloration of pale green, brown, and white. Inside it is white - and nacreous, with a large brown [pg357] area under the apex. - The animal has a powerful foot, by means of which it is enabled - to cling to a rock with great strength. In order to dislodge it, - it is necessary to approach carefully, and, taking the creature - unawares, quickly slip a broad knife-blade under the foot, - otherwise it is quite impossible to tear it from its resting-place. - /A. testudinalis/ lives entirely between tides, and ranges from the - northernmost waters to New York. It feeds upon algae and is a very - sluggish animal. It has been said to leave its resting-place and - wander about in search of food, returning to its original and usual - spot when the tide begins to ebb. (Page 343.) - - ^A. testudinalis,^ variety ^alveus.^ This variety is smaller, more - fragile, and oblong. It lives upon eel-grass, its oblong shell - being adapted to the narrow leaves of the grass. The coloration is - brighter--reddish-brown spots on a white surface. It is exceedingly - common on the New England coast. - - [Illustration: /Acmaea testudinalis/, var. /alveus./] - - ^A. mitra.^ On the Pacific coast there are a number of acmaeas. /A. - mitra/ is often found dead upon the beaches. It is conical in form - and pure creamy-white in color. It looks very much like a clown's - pointed cap. - - ^A. patina.^ This is also very abundant in California. Outside it - is dark in color and is often incrusted with mineral deposits. - Within there is a dark ring around the edge, then a zone of - bluish-white, and a patch of brown just beneath the apex. - - -GENUS ^Lottia^ - - ^L. gigantea.^ This is the largest of the California limpets. - Specimens three inches long have been found. The outer surface - of the shell is rough and brownish in color. The apex is near - one end. Within it is almost black, shining, lustrous, with a - horseshoe-shaped muscle-scar under the apex. The color is bluish - and brown. (Plate LXV.) - - -FAMILY ~FISSURELLIDAE~ - - This is an extensive family, including several genera and a number - of species, commonly known as keyhole-limpets. In the general form - of the shell they closely resemble the true limpets, the /Acmaeidae/, - except that they have a hole, or rather a slit, in the shell just - back of the apex. Often this slit is so long that it has entirely - removed the apex of the conical shell. - -GENUS ^Fissurella^ - - ^F. alternata^, ^F. barbadensis^. These species occur upon the - southern shores of the United States, the latter, however, being - confined to [pg358] extreme southern Florida. /F. barbadensis/ - has heavy longitudinal ribs and is light green within, with a rosy - circle about the apical perforation. (Plate LXV.) - - -GENUS ^Glyphis^ - - ^G. aspersa.^ One of the numerous species belonging to this family - which are found on the west coast of the United States. It is about - one and a half inches long, grayish-white, with sharply raised - longitudinal ridges, slightly rayed, crossed by revolving ribs, - which give to the outer surface a decussated appearance. The apex - is forward of the center, and is entirely replaced by a round - perforation. The edge is wrinkled, and within smooth and white. - - -GENUS ^Lucapina^ - - ^L. crenulata.^ The largest of the keyhole-limpets; the shell - is often four inches in length, while the animal, with its huge - yellowish foot and dark-colored mantle, which is thrown back, - almost concealing the shell upon its back, is much larger. The - apical perforation is very large. Shell flattened, with radiating, - rounded, crowded ribs; brownish-white in color; edge crenulated; - within pure white. It is found at Monterey, but live specimens are - not very frequently seen near the beach. (Plate LXVI.) - - -FAMILY ~HALIOTIDAE~ - - -GENUS ^Haliotis^ - -This family is closely allied to the /Fissurellidae/. The species are -known on the Pacific coast by the name of abalone shells, and in -England and the Channel Islands as ormers or sea-ears. There are no -species of /Haliotis/ on the east coast of the United States, but -one has recently been dredged at a considerable depth in West Indian -waters. This family, with the last, possesses the striking anatomical -feature of having the heart traversed by the digestive tract. It -also has two gills, the degree of torsion in the visceral mass not -being sufficient to have crowded out and destroyed the original -right gill. The shell is spiral, but is so greatly flattened, and -the body-whorl is so greatly extended, that the shell quite loses -the spiral appearance. Along the dorsal side of the shell is a row -of holes, through which project numerous tentacular processes from -the mantle. The outer surface of the shell, before it is polished, -is usually rough and unattractive, but within, when the [pg359] -animal is removed, it displays a most beautiful and highly colored -nacreous surface. The spot near the center of the inner shell -surface where the muscles of the foot were attached is usually -most brilliantly colored. The shell of the abalone is susceptible -of taking a very high degree of polish, and is extensively used in -commerce for colored mother-of-pearl and for inlaid work. /Haliotis/ -is a vegetable-feeding genus. They cling with great tenacity to rocks -about low tide, and it requires skill to remove them without breaking -the shell. There are several species in California. The Chinese use -the abalone for food, and have waged a persistent war upon the family -along the Pacific coast until the specimens are not nearly as common -as formerly. They are also eaten in France and in Japan. - - ^H. splendens.^ The largest and perhaps the most attractive in - appearance of the Californian species. Speaking of this beautiful - shell, Professor Keep says: "Within, a whole rainbow is condensed - in one of the magnificent shells, though the shades of green are - most conspicuous. The coloring in the center is particularly fine, - resembling a peacock's tail. There are about six open holes near - one side of the shell, and its length is about the same number of - inches." (Plate LXVI.) - - ^H. rufescens.^ A large abalone, which sometimes attains a length - of eight or nine inches. It is red in color, with three open holes - in the body-whorl. The outer portion of the shell is usually - incrusted with mineral deposit and overgrown with vegetation. - - ^H. cracherodii.^ Very dark green without, with five to nine holes; - length from one to six inches; spire exceedingly short. Common on - the Californian coast in crevices of rocks at low tide. - - -FAMILY ~TROCHIDAE~ - -This is one of the largest and most interesting families of the -/Mollusca/. It contains many apparently widely separated genera -and a host of species, which for the most part are littoral, the -majority actually living between tide-marks. The typical trochid -shell is top-shaped or pyramidal, having a broad base and many -closely wound flat whorls terminating in a sharp apex. All the -trochids are nacreous within the aperture--a character which is -constant throughout the family. The animal has but one gill (the -left), a short snout, and often frontal lobes on the head. The -edge of the mantle or the epipodial line of the foot is usually -ornamented with from three to five cirri. The tentacles are [pg360] -long and slender, with short peduncles for the eyes; the operculum -is corneous, with a central nucleus. The animals are herbivorous, -feeding upon algae. The trochids are essentially tropical shells, and -the most of the genera which are comprised in the family are only to -be encountered in the warm waters of the Pacific and Indian oceans. -Some forms are very beautiful, and frequently are used as mantel -ornaments, and the shells of one little species, which is opalescent -in its coloring, are still extensively gathered in the East Indies, -to be polished and strung like pearls in necklaces. - - -GENUS ^Margarita^ - -On the Atlantic coast north of Cape Cod the trochids are represented -by the genus /Margarita/, with five or six species. The shells are -small, thin, and globosely depressed, with smooth or transversely -striated whorls. The aperture is nearly circular, with a simple lip. - -[Illustration: /Margarita cinerea./] - - ^M. cinerea.^ This species has several prominent revolving ridges - upon the upper side of the whorls, with finer ones on the base. - Very fine growth-lines cover the entire shell. It ranges all along - the coast north of Cape Cod, but is not usually found between - tides. The writer has dredged many specimens in shallow water at - Eastport and Bar Harbor. - -[Illustration: /Margarita helicina./] - - ^M. helicina.^ A thinner and more globose species than the last, - with a translucent, shining, smooth surface of a yellowish or olive - color. /M. helicina/ is very fond of the leaves of /Laminaria/, and - is often found clinging to them when storms have torn these great - algae from the bottom and cast them upon the shore. At Bar Harbor - they are common upon the eel-grass in Rodicks Weir. This species - can generally be distinguished by its iridescent, metallic luster. - -[Illustration: /Margarita undulata./] - - ^M. undulata.^ A commoner species, perhaps, than either of the - preceding, sometimes found on the rocks of sheltered coves at - exceptionally low tides. Judging from the number often to be found - in the stomachs of fishes, they must be considered excellent food - by the cod and its allied species which thrive along the Maine - coast. No doubt millions of /M. undulata/ are yearly destroyed - in this way. The shell is depressed, with four rounded whorls, a - flattish base, and a large umbilical opening. In color it varies - from rose-red to brown. The surface is decorated with numerous - revolving raised lines placed at uniform distances. Just below - the suture the body-whorl is somewhat undulated with short folds. - Height three tenths of an inch, base four tenths of an inch. - [pg361] - - -GENUS ^Calliostoma^ - -This genus is better represented on the Pacific coast of the United -States than upon the Atlantic. It comprises a series of marvelously -beautiful shells, often exquisitely colored. They are regularly -conical or pyramidal in shape, with flattened bases. One never tires -in the search for calliostomas. They are not common enough to cause -one to lose interest, and whenever a good specimen is captured it -seems as though one had found some gem cut and polished by nature's -skilful hand and prepared for a place of honor in the cabinet. - - ^C. occidentale.^ The only species of this genus found on the - northeast coast. It is larger than /Margarita cinerea/, but - somewhat resembles it. It is shining nacreous within and without, - and has strong revolving ribs, the upper one on each whorl often - being broken into a circular row of white dots. The lip is - crenulated. This very pretty species is not likely to be met with - upon the shore, but may be dredged in shallow water on gravelly - bottoms along the Maine coast. Height about one half of an inch. - -[Illustration: /Calliostoma occidentale./] - - ^C. jujubinum.^ A species which occurs in the waters of Florida. - Its form is almost that of a true pyramid. The sutures can scarcely - be distinguished. The shell is marked by brown and purplish-red - spots on a white background, and has numerous revolving ribs broken - into rows of white dots like little glazed beads. The umbilicus - is funnel-shaped and wide. In Tampa Bay this shell is frequently - found on sponges, and may sometimes be gathered on the beach after - storms, even as far north as Hatteras. There are as many as twenty - species of this genus in American Atlantic waters, but they are - either rare or have deep-water stations. - - ^C. annulatum.^ A remarkable species of /Calliostoma/, found in - California. The whorls are adorned with revolving rows of raised - dots, and the sutures are frescoed in exquisite purple. This - beautiful species lives upon seaweed, and on pleasant days comes - to the surface of the water. It can then be collected from a boat - by drawing in quantities of seaweed. It is very unlikely that the - collector will ever find a specimen upon the beach, for the shell - is too fragile to withstand the rough handling of the waves. Length - one inch. - - ^C. canaliculatum.^ The largest member of this genus to be found - in American waters. It resembles the last species in form, but - lacks the purple sutures. The revolving ribs are very numerous and - prominent. There is no umbilicus. Length one to one and a half - inches. Found on the Pacific coast. - - ^C. costatum.^ A heavier shell than the preceding, with somewhat - more rounded whorls. Reddish-brown in color; numerous revolving - ridges; no umbilicus; about three quarters of an inch in length. It - is found in rocky places, and sometimes in considerable numbers, - just at low-tide mark. Found in California. [pg362] - - -GENUS ^Chlorostoma^ - -This genus is represented in California by several species, the -commonest of which is probably /C. funebrale/--a doleful name, no -doubt given on account of the jet-black color. - - ^C. funebrale.^ The shell is thick and strong, like most - between-tide species, which are constantly exposed to the buffeting - of the waves. It is to be found in countless thousands upon rocks - exposed at low tide, and may be gathered at any time except full - flood-tide, like the littorinas and purpuras of the east coast. - Within the aperture the surface is nacreous and greenish in tint; - the last whorl is drawn in, like gathers, at the suture. The - umbilicus is closed. There is a white nodule at the base of the lip - of the columella. Length one half of an inch to one inch. (Plate - LXVII.) - - ^C. brunneum.^ This species is brown, as its name would indicate, - and there is greenish nacre within the aperture. It lives upon - kelp, or upon rocks at very low tide. Length about an inch. (Plate - LXVI.) - - -GENUS ^Trochiscus^ - - ^T. norrisi.^ A flattened shell with rounded, dome-like spire and - obtuse apex; a fairly common species. It has a wide, deep umbilicus - and a sharp lip. It is of a rich brown color, with dark chestnut - about the umbilical region and greenish-white within the umbilicus; - there is a band of dark olive-green about the inner margin of the - lip. The shell is about two inches in diameter and of a somewhat - greater height. The operculum is multispiral, with a central - nucleus, and is shaggy and rough. Like all other trochids, it feeds - upon algae. It is often found upon the beach after violent storms. - Found in California, south of San Francisco. (Plate LXVI.) - - -GENUS ^Livona^ - - ^L. pica.^ This large and interesting trochid is a West Indian - species which sometimes occurs in Florida. It lives about coral - reefs and rocky shores, attaching itself in vast numbers to the - rocks. This shell is a favorite refuge for large hermit-crabs. It - is a curious sight in certain of the West India islands to see a - /Livona pica/ shell scrambling up a tree, looking very much out of - place upon the back of some terrestrially inclined crustacean. When - well cleaned it is a beautiful shell, with black wavy lines over a - greenish-white nacreous foundation. The animal has a row of waving - cirri upon each side of the mantle, and long, slender tentacles. - It is largely used as an article of diet in the West Indies and - Central America. (Plate LXVII.) - - -FAMILY ~TURBINIDAE~ - -This family is very closely allied to the trochids, the most striking -difference being in the operculum, which in the /Turbinidae/ is -calcareous and usually smooth and very convex on the outside. -[pg363] The shells are nacreous within, and the animal, with its rows -of waving cirri upon each side, is very suggestive of /Trochus/. They -are, for the most part, shallow-water or littoral forms. - -[Illustration: PLATE LXVI. 1, Lucapina crenulata. 3, Chlorostoma -brunneum. 2, Haliotis splendens. 4, Neritina reclivata, enlarged. 5, -Trochiscus norrisi.] - -[Illustration: PLATE LXVII. Livona pica, reduced. Turbo castaneus, -enlarged. Nerita peleronta. Chlorostoma funebrale. Nerita tessellata.] - - -GENUS ^Turbo^ - - ^T. castaneus.^ This species has a range as far north as Cape - Hatteras, and is especially abundant at Tampa, on the west coast of - Florida. The peculiar operculum is sufficient to identify the genus - at once. One variety of this species has a crenulated shoulder upon - the body-whorl and is referred to as ^Turbo crenulatus^, A series - of intermediate forms establishes the specific identity of the two - varieties. (Plate LXVII.) - - -FAMILY ~NERITIDAE~ - -The /Neritidae/ are strictly littoral forms, almost entirely confined -to the warmer waters of tropical seas. The animal preserves the usual -diatocardian features--has a short snout and long tentacles. Unlike -the trochids and /Turbo/, it has no cirri along the epipodial margin. -The shells are peculiarly shaped, the spire being greatly flattened -and scarcely noticeable on account of the unduly large development -of the body-whorl; thus the shell takes on a decidedly patelliform -appearance. It is without an umbilicus. In the principal genus -/Nerita/ the outer lip is sharp on the edge, but greatly thickened -just within. - - -GENUS ^Nerita^ - - ^N. peleronta.^ This shell has two teeth on the wide, flat - columellar lip, and about them is a blotch of red, suggesting - blood. The common name of this shell, "bleeding-tooth," is very - appropriate. Found in southern Florida. (Plate LXVII.) - - ^N. tessellata^ is a smaller species, with heavy revolving ribs, - and is further decorated with transverse oblique black lines. The - operculum is calcareous. Both of these species have the habit of - absorbing the entire inner portion of their shells. They belong - to the West Indian fauna, and occur in great numbers on rocky or - coral shore stations. They also may be found on the east Florida - coast, well to the south. A third species, ^N. versicolor^, often - occurs, associated with the other two. It is somewhat smaller than - the others and can easily be distinguished by the four teeth on - the columellar lip, the edge of the columella being convex. (Plate - LXVII.) - - -GENUS ^Neritina^ - -The genus /Neritina/ is very closely allied to the last, having quite -the same form of shell; but it is usually more globular and [pg364] -variously ornamented by bright spots or zigzag lines of coloration. -The neritinas have acquired the habit of ascending rivers, until -they have become almost wholly a brackish- or fresh-water genus. -The metropolis of this genus is in the South Sea Islands, where it -attains a wonderful development in the clear running streams of the -volcanic islands. - - ^N. reclivata.^ A very pretty olive-green species, with very - fine, wavy, longitudinal lines of coloration, found in almost - all Floridian streams above the action of the tide. The nacre of - the columella and within the aperture is bluish-green, and the - operculum is rich olive. (Plate LXVI.) - - ^N. viridis.^ A small, intensely green species, which, unlike most - neritinas, is strictly marine. It belongs to the great West Indian - faunal province, but is occasionally found upon the shores of - Florida and of Texas. - -The prosobranch gasteropods thus far considered (belonging to the -suborder /Diatocardia/) all show by their anatomical structure that -the process of visceral torsion, though carried very far within them, -has not been complete enough to crowd out and finally destroy one -of each of the paired organs. Both auricles of the heart (with some -exceptions) were left intact. - - -SUBORDER ~MONOTOCARDIA~ - -In this the second suborder of the prosobranch gasteropods, the -twisting visceral process has been carried to the extreme. The -heart has but one auricle. There is but one gill (on the left -side), and this is attached to the inner side of the mantle flap. -In other respects the presence of certain specialized organs would -probably indicate that gasteropods belonging to this suborder are -a step higher in the scale of life than those which belong to the -/Diatocardia/. - - -FAMILY ~JANTHINIDAE~ - - -GENUS ^Janthina^ - -The genus /Janthina/ has an exceedingly thin and semi-transparent -shell, deep violet in color on the base and lighter blue on the -spire. An interesting feature of this genus is the mode of depositing -the ova. The female exudes from a gland in the foot a [pg365] -glutinous secretion which hardens in water, and, being filled with -air-bubbles, constitutes a float. On the under side of this are -deposited the eggs in rows of little capsules. While attached to this -float it is impossible for a /Janthina/ to sink, and hence it is that -so many of these creatures are sacrificed in onshore gales of wind. - - ^J. fragilis.^ The shell of this species is so brittle and fragile - that it is very clearly not adapted to a life near shore. It is in - reality a pelagic species which is occasionally blown ashore during - easterly gales along the Atlantic coast of the United States. Vast - numbers of these pretty creatures are sometimes encountered far out - at sea, floating quietly on the surface. When storms drive them - upon the beach, they become utterly helpless; since their foot - is not adapted for crawling upon the sand, they soon perish, and - their brittle shells are demolished by the surf. In Florida the - beaches are sometimes fairly lined with /Janthina/ shells, which - make a band of purple along the high-tide mark as far as the eye - can reach; then it may be years before they again appear. (Plate - LXVIII.) - -[Illustration: /Janthina fragilis/: /FL/, float; /O/, ova; /Pr/, -proboscis; /Br/, branchiae; /F/, foot.] - - -FAMILY ~SCALIDAE~ - - -GENUS ^Scala^ - -The shells of /Scala/ have such a peculiar scheme of decoration -that once seen they can never be mistaken. They are generally -pure white, with well-rounded whorls, all of which are crossed -at even distances by greatly elevated and smooth ribs. Each rib -represents a rest-period, when the creature thickened the rim -of the shell-aperture. The aperture is generally round, with a -continuous lip. The animal has a retractile proboscis and long, -slender tentacles with eyes at the outer bases, and is a predaceous, - [pg366] carnivorous creature. Some Asiatic species of this genus, -remarkable for their beauty and rarity, have been greatly prized by -collectors. A single specimen of the now well-known ^S. pretiosa^ of -China has been sold for two hundred dollars--a fancy price, indeed, -for a shell which can now be bought for a dollar! There are over -fifty species of /Scala/ on the Atlantic coast, but most of them are -either rare or belong to a zone of deeper water; there are, however, -four or five species which are exceedingly common. - - ^S. lineata.^ A species which ranges from Hatteras to New England. - It has about eight whorls, and is slightly brownish in color. The - ribs are robust and not greatly elevated; there are from seventeen - to nineteen on the body-whorl. The shell is sometimes painted with - a few revolving brownish lines. - -[Illustration: /Scala lineata./] - - ^S. multistriata.^ The transverse ribs are much smaller but very - numerous; the small spaces between them are marked with many fine - revolving lines. Found from Cape Cod southward. - -[Illustration: /Scala multistriata./] - - ^S. groenlandica.^ Essentially an arctic species, which has found - its way down to the New England coast. It is readily distinguished - by the flattened, coarsely rounded, revolving ribs, which follow - the volutions of the spire. Over them are the usual transverse - heavy ribs peculiar to this genus. - -[Illustration: /Scala groenlandica./] - - ^S. angulata.^ The whorls touch one another only by the ribs, - of which there are nine to each volution. This species has a - remarkably wide range, occurring from Cape Cod to southern Florida. - (Plate LXVIII.) - - These four species vary from one half of an inch to one inch in - length. All of them are found on the beach after storms or may be - dredged in shallow water near the shore. - - -FAMILY ~NATICIDAE~ - -This large and interesting family is well represented in the Atlantic -waters of the United States, but its more beautiful members live -in the tropics. The New England and New Jersey species are dull in -color, but offer much of interest to the collector and student. The -foot is enormously large, and carries in front a great shield-like -fleshy process, which curves back over the head of the animal and -serves as a plow in pushing its way through the heavy wet sand of -the beach. When the creature is thus seen extended in the act of -crawling, one wonders how it is possible for it to withdraw so great -an amount of body into its shell; but if it is suddenly seized or -irritated, it will quickly [pg367] demonstrate its ability -to hide itself completely within its house and to close the door -very effectively by means of its operculum. The eyes seem to be -wanting, or they are concealed under the skin of the head. The shell -is usually quite large, with a depressed spire and well-rounded -whorls--especially the body-whorl, which appears to be greatly -swollen. The umbilicus is usually open and moderately large, the lip -simple. - -[Illustration: PLATE LXVIII. Janthina fragilis. Sigaretus -perspectivus, upper side. Scala angulata, enlarged. Sigaretus -perspectivus, under side. Natica canrena. Crepidula aculeata.] - - -GENUS ^Polynices^ (^Lunatia^, ^Natica^). - - ^P. heros^ (generally referred to as ^Lunatia^ or ^Natica - heros^). One of the commonest large shells and one of the most - characteristic species of the New England and New Jersey littoral - fauna. It is exceedingly common along the Long Island shore, where - it may be found on the open beach, in pools with a sandy bottom - left by the receding tide. It is usually partially and frequently - wholly buried in the sand. The umbilicus is open and large, the - operculum corneous, and the shell heavy and ashy-white to brownish, - with (when young) a yellowish epidermis. Its length is from two to - four inches. It has no ornamentation whatever. /P. heros/ is a most - voracious creature and spends its time in hunting for flesh--either - alive or dead--to devour. It feeds upon dead fish, or upon other - mollusks whose shell it is able to pierce by means of its radula, - making a little round hole through which it sucks out the flesh - from within. The curious egg-cases of this species have already - been referred to. (See Plate I.) It glues together particles of - sand into the form of a basin with the bottom knocked out and - broken on one side. In the gelatinous substance of this basin it - deposits its eggs in a regular order. These hatch out in midsummer. - Egg-cases of this kind can always be found wherever /Polynices/ - lives. For a long time naturalists were greatly puzzled by these - curious things, and their blunders are recorded in earlier works, - where these egg-cases have been elaborately described as living - animals belonging to various invertebrate orders. The largest and - best specimens of /P. heros/ are to be found south of Cape Cod. - (Page 343.) - - ^P. triseriata.^ A small shell of exactly the same shape as /P. - heros/, but decorated with three revolving series of bluish or - chestnut spots. It is pretty well determined that this so-called - species is only the young of /P. heros/. It is very abundant all - along the coast. - - [Illustration: /Polynices triseriata/, young; /Polynices - triseriata/, older specimen.] - - - ^P. duplicata.^ This is even more abundant than /P. heros/. It - has a flatter shell, with an obtuse apex and dome-like spire. - The umbilicus is partly or wholly closed by a thick, callous, - shelly process thrown off from the columellar lip, and is chestnut - in color. The surface of the shell is smooth, often polished, - ashy-white below and light chestnut above. The operculum is - corneous. The length of the shell varies in different localities - from one half of an inch to about two [pg368] inches; the breadth - slightly exceeds the length. /P. duplicata/ has a very extensive - range, from the Gulf of Mexico to Newfoundland. The largest and - finest specimens are found in the vicinity of New York and at - Hatteras. In Florida they are usually smaller. This species cannot - be confounded with any other upon our coast on account of the heavy - callous deposit over the umbilicus. Its habits are similar to those - of /P. heros/. - - [Illustration: /Polynices duplicata./] - - [Illustration: /Natica clausa./] - - ^Natica clausa.^ A Northern species which is fairly abundant on the - Maine coast. It has a shelly operculum, and the umbilicus is neatly - closed by a pure white, shining callosity. Its length is about one - half an inch, its color livid white to light brown, white within. - The calcareous operculum at once determines this shell. This - species (as well as the following one) has retained the generic - name of /Natica/ because of the shelly operculum, as explained - below. - - ^N. canrena.^ One of the handsomer species of /Natica/, which - occurs in Florida. Sometimes it is seen as far north as Hatteras. - The shell is white, with bars of light chestnut circling the - whorls, and with zigzag lines of darker purplish hue crossing them. - The base of the shell is white. The aperture is large and flaring, - and is purplish within. The umbilicus is partially closed by an - entering callous plug. The operculum is calcareous, with eccentric, - deeply cut grooves. Found in sandy stations just about low-water - mark. (Plate LXVIII.) - - ^P. lewisii.^ A species which occurs on the west coast of the - United States. It resembles its New England relative /P. heros/ - very closely. /P. lewisii/ is a Northern species, and does not - range south of Oregon. Professor Keep mentions one specimen of the - size of a six-inch globe, but such dimensions are very unusual. A - good-sized specimen need not exceed four inches in height. - - ^P. recluziana.^ A species well known on the southern coast of - California. The umbilicus is closed by a thick, highly polished - white callosity, and the general shape of the shell is strongly - suggestive of the common east-coast species /P. duplicata/. A large - specimen is about two inches in diameter. - - [There has been much confusion in the generic nomenclature of - this family. The old name /Natica/ once did service for all the - species; then the names /Lunatia/, /Neverita/, and /Polynices/ were - applied to certain special forms; but it has been wisely proposed - by conchologists to use the name /Natica/ for those forms having - a shelly operculum, and to adopt the name /Polynices/ for those - having a corneous operculum. /Lunatia/ and /Neverita/ have become - subgenera of /Polynices/.] [pg369] - - -GENUS ^Sigaretus^ - -A very interesting species of this genus occurs on the east coast, -sparingly in New Jersey, but very abundantly south of Hatteras. -/Sigaretus/ is a modified /Natica/. The spire is flattened and -minute. The body-whorl, being greatly expanded, gives a wide, -flaring, oblique aperture. The shell is ear-shaped and white, with -fine revolving lines. There is no umbilicus. The operculum is small -and rudimentary. The animal is large, with an enormous foot and -greatly developed propodium, and is a sand-dweller. The common -east-coast form is ^S. perspectivus^. (Plate LXVIII.) - - -FAMILY ~CAPULIDAE~ - - -GENUS ^Crepidula^ - -[Illustration: /Crepidula fornicata./] - - ^C. fornicata.^ All collectors of mollusks on the Atlantic coast - sooner or later encounter this exceedingly common species adhering - to oyster-shells or scallops, and often to other large live shells. - It is cast upon the beach along the entire length of the Atlantic - coast. The shell is obliquely oval, dull whitish in color, and - either smooth or rough or even ribbed, according to the nature - of the surface to which it clings. The spire is almost entirely - suppressed, the little inconspicuous apex being turned to one - side and closely pressed down against the body of the shell. When - looking into the interior of the shell one is reminded of a boat, - for the upper portion of the aperture is covered by a horizontal - shelly partition, called the diaphragm, a space being left below - which would correspond to the forecastle of a ship. The "stern" is - round, and the "bow" is suggestively pointed. - - [Illustration: /Crepidula plana./] - - ^C. plana.^ In this species the shell is white and flat, or - slightly concave. Although it is pointed at the "bow" end and - square at the "stern," the nautical resemblance stops there, - because, being flat, there are no swelling sides and bow. The - diaphragm is about one half the length of the shell, convex, - shining, white, and translucent. /C. plana/ lives generally within - the aperture of large dead shells. It has a wide range, from Maine - to Florida. - - ^C. aculeata.^ A common Floridian species which has a remarkable - range, being found in nearly all the tropical and semi-tropical - waters of the world. It is smaller than /C. fornicata/, is - reddish-brown with a white diaphragm, and has several radiating - ribs on the back, which are inclined to be nodulous. (Plate - LXVIII.) [pg370] - - On the Pacific coast the following species are found: ^C. adunca^, - with a strongly recurved apex, and less than one inch long; ^C. - rugosa^, rough, brown, with the apex lying on the edge of the - shell, and one inch in length; ^C. navicelloides^, almost identical - with the east-coast /C. plana/. /C. aculeata/ also appears. - - -GENUS ^Crucibulum^ - -/Crucibulum/ has a peculiar rounded shield-like form, with a very -small apex on one side. Within there is a cup-shaped appendage -attached by one side to the inner margin of the shell. This latter -feature at once determines the genus. - -[Illustration: /Crucibulum striatum/, from above.] - -[Illustration: /Crucibulum striatum/, from below.] - - ^C. striatum.^ This species has radiating riblets, cut by circular - lines of growth. No dimension would quite reach an inch. It is a - common shell on the Atlantic coast, and will be found adhering - to stones and other shells, but it is not, strictly speaking, a - littoral species. - - ^C. spinosum.^ The shell exhibits a strong tendency to spinous - processes on its back. Found along the southern part of the - California shore. - - -FAMILY ~LITTORINIDAE~ - - -GENUS ^Littorina^ - -/Littorina/ is probably the most characteristic genus of Northern -littoral regions. Together with some of its allied genera it is also, -probably, equally characteristic of various tropical littoral faunas -all over the world. The family comprises strictly between-the-tides -genera and species. Indeed, it is suspected that some species of -/Littorina/ are making very fair progress toward a terrestrial -condition, for they actually live above high-tide mark,--even in -the branches of overhanging trees,--and must certainly pass days at -a time out of their natural element. That such a transformation is -possible need not for a moment be doubted, for there are many land -mollusks to-day that give abundant evidence of having been at some -past time aquatic or marine species. These changes in nature are -constantly going on, and the gradual substitution of a lung for a -gill is no very startling metamorphosis. [pg371] - -The littorinas fairly swarm in favorable localities upon all shore -stations. In Maine and Massachusetts the bold, rocky coast furnishes -a home for several species. Often the rocks at low tide are black -with them; the algae that cling in wet masses to the exposed rocks -are alive with them. One cannot walk about in such localities -without crushing hundreds of specimens. Sometimes they will be found -clinging in clusters upon the piling of old wharves, or crawling -about the bottom at or about the low-tide mark. The best specimens -of /Littorina/ are found in stations where they are bathed twice a -day by pure, uncontaminated sea-water; those living near the mouths -of streams, or where the water is brackish or impure, are usually -small and degenerate. They are vegetable feeders, and have received -the common name of "periwinkles." In Great Britain they are used -among the poorer classes for food. The animal has a short, broad -muzzle, and eyes at the outer bases of the tentacles. The foot is -longitudinally grooved, and there is a rudimentary siphonal fold in -the mantle. The shells are turbinated, usually heavy, few-whorled, -and with a round aperture. - -[Illustration: /Littorina litorea./] - - ^L. litorea.^ This is supposed to be an importation from the Old - World--to have come over by way of Iceland and Greenland, and - then to have migrated down the Labrador coast. For many years - Cape Cod formed a barrier to its advance, but now the species is - abundant at Newport, and is reported at New York. It occurs on - the Maine coast in astonishing numbers, living in vast colonies - on the rocks exposed at low tide. The shell is thick, imperforate - (no umbilicus), and usually has flat, spiral ribs. The columella - is broad and white; the lip thin and black. The general color - varies from black to olive or to dingy gray--sometimes reddish. - The operculum is corneous, with the nucleus near the outer edge. - Despite the variableness of this very common shell (the variations - being chiefly in the height of the spire), it has certain - unmistakable characteristics which, once seen, will enable the - collector to determine it at once. - - [Illustration: /Littorina rudis./] - - ^L. rudis.^ A smaller species than the last. It is strong - and coarse, with revolving grooves and ribs, or smooth, with - interrupted whitish bands and spots. A very common variety of - this species is much smaller than the typical form, being about - one sixth to one fourth of an inch long, smooth, with white and - yellowish spots on olive. It clings to the rocks near high-tide - mark, and is usually found attached to its resting-place by a - bit of hardened mucus. While the typical /L. rudis/ is heavy and - banded, with a moderately high spire and no color, this [pg372] - variety is thinner, with a higher spire and smoother surface, - and has a color-scheme of decoration. It would be impossible - to disconnect the two, for a large series of specimens will - demonstrate beyond doubt, through every minute degree of variation, - that the two forms belong to one and the same species. The station - of /L. rudis/ is much the same as that of /L. litorea/, but the - smaller colored variety of /rudis/ prefers quieter and more - sheltered spots. It is occasionally found on reeds and grasses, - on the piling of wharves, on large boulders above the line of - algae, and on algae. It has been the writer's experience not to find - /rudis/ and /litorea/ associated together. - - [Illustration: /Littorina palliata./] - - ^L. palliata.^ A low-spired, globular shell with a large, tumid, - smooth body-whorl. The columella is flattened, curved below, and - imperforate. The color is exceedingly variable, but is usually - bright, shining olive, and this is especially the case with those - individuals that find their station in the dense masses of algae - that form so conspicuous a feature of a low-tide scene on a rocky - New England coast. From pure olive-green to yellow or bright red, - with revolving black bands, seems a long chromatic leap, but it - is not too great for the Designer of these pretty little globular - shells. As a rule, the color of the shell simulates pretty closely - that of the seaweed upon which it lives, and inexperienced eyes - may easily overlook hundreds of specimens, all within close reach. - The banded varieties are less common. The head of the animal is - somewhat orange in color, the foot slate. The distinguishing - features of this species are the smooth, globular shell, the low - spire, the broadly flattened columella, and the orange-colored head - of the animal. It is found on /Fucus/ between tides, and often - associated with /L. rudis/, on the whole coast north of New Jersey. - The three preceding species are distinctly boreal in their range, - but their place is taken in southern Atlantic waters of the United - States by the following exceedingly common species: - - [Illustration: /Littorina irrorata./] - - ^L. irrorata.^ A solid, robust shell, which attains a length of - about one inch. It is in many respects suggestive of /L. litorea/, - its Northern relative, but the spire is higher, with straighter - outlines, and the apex is acute. The surface is ornamented with - closely set, revolving ribs; the sutures are indistinct; the lip - is thin, though thickened just within; and the color is whitish to - pale cinereous greenish, sometimes spotted with broken brownish - lines. Within it is white, with a reddish tinge on the columella, - and brownish spots on the edge of the lip. This species ranges from - Maryland to Texas; its station is between tides. - - ^L. angulifera.^ As the last species resembles /L. litorea/, so - this other common Southern form resembles a greatly developed and - large /L. rudis/ of the smoother variety. It has a high-spired - shell, with an acute black tip. It has about six whorls, which are - variously decorated by wavy, oblique black lines and revolving - black lines broken into series of dots and larger spots near the - suture. The ground-color varies from yellow to purple. None of - the colors are very vivid. Within it is yellowish-white. This - species has a much thinner and more delicate shell than any of - the littorinas thus far considered. It is common on the piling of - wharves and in sheltered nooks everywhere [pg373] between tides. - It is essentially a tropical species of very wide and extended - range, but it does not occur north of St. Augustine. At Tampa it - has been found in vast numbers. (Plate LXIX.) - - The California coast furnishes two more species of /Littorina/. - Their station is among the rocks between tides, and their habits - are quite the same as those of the east-coast species. - - ^L. scutulata.^ In this species the color is of various shades, - generally dark gray, mottled with white spots. A good-sized - specimen measures one half of an inch in length. The spire is high; - the columella flattened, broad; the shell is purplish-white within - the aperture. (Plate LXIX.) - - ^L. planaxis.^ Somewhat larger than the last; wider; with a lower - spire; grayish in color, sometimes speckled with white; chest - nut-brown within. The columella is remarkably flattened, and a - portion of the whorl next bordering the columella is excavated as - though eaten away by the animal. These two species are often found - associated on the rocks. (Plate LXIX.) - - -GENUS ^Lacuna^ - -[Illustration: /Lacuna vincta./] - -Closely allied to /Littorina/ is the genus /Lacuna/, one species of -which, ^L. vincta^, is very abundant on the New England coast. A -curious and distinguishing feature of this genus is the umbilicus, -which forms a lengthened groove along the columella. /L. vincta/ -rarely exceeds one half of an inch in length, and is thin, with a -pointed spire of five whorls. It is either of a uniform horn-color, -or purplish, or banded with chestnut. It may best be found upon -marine plants in sheltered places, or may sometimes be gathered in -quantity from the roots of /Laminaria/ washed in by storms. - - -GENUS ^Tectarius^ - -The specific representatives of this genus are mostly tropical. ^T. -nodulosus^ is abundant in Florida. It is about one half of an inch -long, and has the flattened columella and round mouth characteristic -of /Littorina/. It is decorated somewhat elaborately by revolving -rows of nodules which cover the entire shell. Its station and habits -are the same as those of /Littorina/. - - -FAMILY ~CERITHIIDAE~ - -In this family we meet with a somewhat new type of shell--the long, -turriculate shell, with many whorls and with a channeled [pg374] -aperture. The /Cerithiidae/ include a large number of genera, mostly -tropical in distribution. Their shells are usually highly ornamented -in various schemes of sculpture, but they lack beauty in color. The -animal is provided with a siphon, as is indicated by the anterior -canal of the shell. The operculum is corneous, with a nearly central -nucleus. - - -GENUS ^Cerithium^ - - ^C. floridanum.^ A very common species on the west coast of - Florida, also sparingly found at Hatteras. It has eight or ten - whorls, a gradually tapering spire, and a sharp apex; the aperture - is oblong, with a deeply cut anterior canal projected to the left - and backward (when the specimen is held apex up, with the aperture - toward the observer). The sculpture is elaborate, consisting of - many rows of revolving ribs, and close to the suture there are - circling rows of nodes. There is a curious hump just to the left - of the aperture, which is quite characteristic of the genus. The - color is whitish-gray; the length one and a quarter to one and a - half inches. Station, shallow water in lagoons and sheltered spots. - (Plate LXIX.) - - ^C. muscarum.^ Another Floridian species, somewhat smaller than the - last (one inch in length). It has heavy, prominent, transverse ribs - crossed by circling rows of chestnut spots, one heavy revolving - rib around the base; eight or nine whorls; a high-tapering spire; - and a sharp apex. The aperture is oblong, with the anterior canal - projecting to the left. The columella is arched; the color shining - gray to very light purplish. This very pretty little shell may be - gathered literally by the shovelful all along the west Florida - coast in sheltered spots, on sandy and shallow bottoms. (Plate - LXIX.) - - ^C. minimum.^ A still smaller Floridian shell, with jet-black - aperture and anterior canal projecting horizontally to the left. - The sculpture-plan is of revolving ribs and a series of white - granules just below the sutures. Its station is the same as that of - the last. Often the bottom of a lagoon will seem to be literally - paved with these somber-hued little shells. From Tampa Bay to - Charlotte Harbor they are very abundant. - - -GENERA ^Bittium^, ^Triforis^ - -These are allied genera, having numerous species upon our coasts, but -the shells are so small that the inexpert collector is not likely to -notice them. Hosts of these minute, turreted, decussated, blackish -shells are to be found on the wiry grasses of salt-marshes. They are -also found on algae at low-water mark. In /Triforis/ the whorls turn -to the left. Range from Cape Cod to South Carolina. [pg375] - - -GENUS ^Cerithidea^ - - ^C. scalariformis.^ This species has the suggestive outlines of the - family, but the aperture is simpler. The outer lip is considerably - thickened, sinuous, and yellow; there is a very slight notch at the - angle of the columella, and the lip serves for an anterior canal. - The apex is wanting by reason of the usual truncation of two or - three whorls of the spire. There are revolving ribs on the base; - longitudinal ribs elsewhere. The color is a dingy drab; within, - brownish-yellow. It is found in brackish water in Georgia and - Florida. This species is said to suspend itself from overhanging - vegetation by means of glutinous filaments. It may remain out of - water for an almost indefinite time. (Plate LXIX.) - - ^C. sacrata.^ A species very common on the mud-flats of San - Francisco Bay. It is a high-spired shell of ten heavily ribbed - whorls, with a series of revolving ribs on the body-whorl. The - outer lip is sinuous, and the columella is slightly twisted. It is - nacreous and brown within, dingy blue-black without. Length one - inch to an inch and a quarter. (Plate LXIX.) - - -FAMILY ~VERMETIDAE~ - - -GENUS ^Vermicularia^ - -[Illustration: /Vermicularia spirata./] - - ^V. spirata.^ This is a very curious creature when considered from - the point of view of the gasteropod mollusk. It seems at first as - though it would be better to regard it as a worm which had created - for itself a calcareous covering. But it is a true prosobranch - notwithstanding the fact that it has departed widely from the - conventional design in the fashioning of its shell. At first the - shell starts out in a regular form, and then the whorls become - separated, finally wandering about in a seemingly aimless manner. - The irregular prolongation sometimes measures ten inches in length. - The animal is in no way remarkable except in having the viscera - greatly elongated and the foot very short and broad. The color of - the animal is light brown with black spots; the shell-color is - rufous or ashy-white. Shells of this genus are often found grouped - together in an inextricable mass. It is found in shallow water from - New England to Florida. - - -FAMILY ~STROMBIDAE~ - -This is a particularly interesting family, but it is tropical, and is -represented on the shores of the United States by only one [pg376] -genus, /Strombus/, of which we have but a few species. /Strombus/ -is a scavenger,--a buzzard among mollusks,--and its sense of smell -is evidently very acute. Its eyes are much more highly developed -than the usual gasteropod visual organs, and they are placed at -the tip-ends of two very substantial eye-stalks or-pedicels. The -tentacles are slender and project from the eye-pedicels. The foot -is curiously developed; that portion of it which would naturally -constitute the creeping-disk is exceedingly small, but the metapodium -(the hinder part of the foot, upon which the operculum is situated) -is very large. The corneous operculum upon its end, which is far too -small to close the entrance of the shell when the creature retires -within it, looks like a claw. Instead of creeping along the sand, -/Strombus/ proceeds by jumps or awkward leaps, turning its heavy -shell first to one side, then to the other. The shell is usually -heavy, with the outer lip greatly thickened. - - -GENUS ^Strombus^ - - ^S. pugilis.^ The very common Floridian species, often three to - four inches in height, with a short spire covered with nodes or - short, obtuse spines, which are also found upon the shoulder of the - body-whorl (sometimes smooth). The aperture is long, with a wide - notch in the outer lip and a posterior canal. Living specimens have - a tough, leathery epidermis covering at least the body-whorl. The - color is brownish. The columella is covered with a fairly thick - callous deposit, and, as within the aperture, is highly polished, - and deep purple, blackish-chestnut, or vivid carnation-red in - color. The smoother varieties have gone under the name of ^S. - alatus^, but the identity of the two species is assured. This - pugilistic /Strombus/ is a very active mollusk, and when placed in - a boat will sometimes effect its escape over the side in a most - surprising manner. The species is very abundant in all the shallow - waters of Florida. A piece of meat on a string, left overnight in - some sheltered sandy spot where there are from six to eight feet of - water, will surely attract them. In Florida, where the waters teem - with life, unless the bait is protected in a wire cage, the chances - are that the hosts of crustaceans and fish will make away with it - long before the strombs can arrive on the scene. (Plate LXX.) - - ^S. gigas.^ One of the largest of gasteropods, very common on the - Florida Keys and also occurring in southern Florida. Hundreds of - thousands of these shells have been sent to Europe from the Bahamas - to be cut into cameos. This familiar shell is to be seen everywhere - in the South, placed about flower-gardens and lining the paths - and walks in yards. It is generally known in Florida and the West - Indies as the "conch-shell." The animal is used as food in Key - West, and is very generally eaten throughout the Bahamas. From - their habit of eating [pg377] these animals the natives of some - of the Bahama Islands are themselves called "Conchs." The rich pink - color of the shell is very striking. - - There are perhaps seventy-five or eighty species of /Strombus/ - inhabiting the tropical seas, and many of them are highly prized by - collectors on account of their great beauty. - -[Illustration: PLATE LXIX. 1, Littorina angulifera, twice natural -size. 2, Littorina scutulata, much enlarged. 3, Littorina planaxis, -enlarged. 4, Cerithium floridanum. 5, Cerithium muscarum. 6, -Cerithidea scalariformis, enlarged. 7, Cerithidea sacrata.] - -[Illustration: PLATE LXX. 1, Strombus pugilis. 2, Cypraea exanthema. -3, Trivia pediculus. 4, Trivia californica. 5, Trivia quadripunctata.] - - -FAMILY ~CYPRAEIDAE~ - - -GENUS ^Cypraea^ - -/Cypraea/ is one of the "aristocratic" genera. Whether the shell -or the animal itself is considered, there is probably no genus of -mollusks which offers so much of beauty and interest to the collector -and student. The genus is a tropical one, and finds its metropolis -among the coral-fringed islands of the equatorial Pacific. Despite -their brilliant colors and general attractiveness, the cowries--for -such is their popular name--are very modest and shy; they prefer to -hide among rocks, where they may be secure from molestation, for -probably their conspicuous appearance is a real source of danger -to them. In the animal of /Cypraea/ the mantle is provided with two -large lateral lobes, which are reflexed and meet over the top of the -shell; thus, when the mantle is fully extended, the shell is entirely -concealed. These mantle lobes are often furnished with numerous -forked, tufted, or ramified filaments. The foot is long; there is -no operculum. The color of the animal is often very striking in its -intensity. A description of the cowry-shell is hardly necessary, so -familiar is every one with it. A deposit of enamel is made all over -the shell, and its painting and decoration, usually very elaborate, -is reserved for the adult as a final process in the artistic -completion of its home. The aperture is as long as the shell, is -channeled at both ends, and is toothed along both margins. The spire -is insignificant and is concealed by layers of enamel. In the young -the shell has a very different appearance, resembling a sharp-lipped -/Oliva/, and its scheme of coloration may be entirely different from -that employed by the adult. - -Among the /Cypraeidae/ are many remarkable species. The splendid -^Cypraea aurantia^, a native of the Fiji Islands, is one of the -shells most sought after by enthusiastic collectors. The natives -[pg378] learned its value long ago, and hold specimens of it at very -substantial prices. It is worn as an ornament by chiefs and as a mark -of distinction. The well-known ^C. moneta^, also a native of the -Pacific Islands, has been very extensively used as money throughout -the South Seas and in Africa. There are many collectors of shells who -confine their efforts almost exclusively to this and to one or two of -the other "aristocratic" genera. From an esthetic point of view this -is very natural, but biologically the less pretentious mollusks are -quite as interesting. - -Of the one hundred and fifty or more species in existence only three -are to be found upon the Atlantic coast of the United States, and the -chances are decidedly against the finding of any of them north of -extreme southern Florida. - - ^C. exanthema.^ A species not uncommon at Key West, where it may - be seen slowly crawling about the mangrove roots near the water's - edge. It attains a length of from four to six inches, and is so - highly polished that a good specimen could be used as a mirror. In - color it is shining, light chestnut, clouded with purple; the lips - are a dark, very rich chestnut; over all are whitish spots which - appear to shine forth from beneath the enamel. Lengthwise along - the middle of the back is a zone of lighter color which reflects a - purplish sheen. (Plate LXX.) - - ^C. spurca.^ Another Floridian species, properly belonging to the - West Indian fauna. It is not more than one half an inch long, and - is white in color, but it is so thickly dotted with yellow spots - upon the back that it would pass for a yellow shell. The base is - pure white. The surface of the shell glistens in the light. - - -GENUS ^Trivia^ - -In the genus /Trivia/ the shell is shaped in every way like that -of /Cypraea/, but its surface is never smooth. In the middle of the -back is a longitudinal groove, from which run transverse ribs, which -continue around to and enter into the aperture. The shells are always -small, never exceeding one half of an inch in length, and their color -is generally reddish or brownish, passing to pink. - - ^T. pediculus.^ A Floridian species, first described by the great - naturalist Linnaeus. Like most of the descriptions of the earlier - naturalists, this is very short and inadequate, and would apply - equally well to almost any /Trivia/. The color is rose-pink, with - several large brownish splashes on the back. The spire is entirely - hidden. It is found in shallow water in pools, and on the beach - after storms. (Plate LXX.) [pg379] - - ^T. quadripunctata.^ Much smaller than the preceding; rose-red, - with four conspicuous reddish-brown dots on the back, two on each - side of the median dorsal groove. Found in Florida. (Plate LXX.) - - On the California coast are also several species of /Trivia/ and - one /Cypraea/, but they belong to the Southern California peninsula, - and are not commonly found farther north than Santa Barbara. The - cowry is called ^C. spadacea^; it grows to a length of about two - inches, is highly polished, with white base and sides, and is - bright chestnut above. As is usual in the cypraeas, the spire is - covered with enamel. - - ^T. californica.^ A species found at Monterey and thence south. - It lacks the median dorsal groove, and has a whitish color-streak - instead. The ribs are white, and the ground-color of the shell - is dark brownish-red. These little shells, when found upon the - beach, are called "coffee-shells," from their somewhat striking - resemblance to the coffee-bean, being flat on one side and rounded - upon the other, and otherwise resembling it in size and color. - (Plate LXX.) - - ^T. solandri.^ This species may be found at Santa Barbara and San - Diego. It is twice as large as the last species, and has a very - deep groove in the back and widely separated ribs. Color rose to - brown. The groove on the back penetrates into the white portion of - the shell. - - -FAMILY ~DOLIIDAE~ - -This small family furnishes two conspicuously handsome species -belonging to the genus /Dolium/, which range from Hatteras southward -into the West Indies. - - -GENUS ^Dolium^ - - ^D. galea^ and ^D. perdix^. The animal in both of these species - has a relatively large foot, which spreads out while in the act - of creeping and seems far too bulky ever to be withdrawn into the - shell. It is square in front, and, bulging out far to each side, - tapers to a blunt point behind. The most noticeable feature of the - animal, however, is the great development of its proboscis, which - is quite as long as the shell itself. The siphon is also long and - is curved over the back of the shell. The operculum is wanting in - adult specimens. The shell of /D. galea/ sometimes attains a length - of eight inches, with a diameter of about six inches; the other - species is not quite so large. They are both ventricose, thin, - inflated shells, with large body-whorls and crenulated lips. Both - are slightly umbilicated and ornamented with revolving, regularly - spaced ribs. The ribs of /D. perdix/ are not so highly raised, - but they are painted with light reddish-brown spots. /D. galea/ - is white, with a lower spire and deeply channeled sutures. (Plate - LXXI.) - - -GENUS ^Pyrula^ - - ^P. papyratia.^ One of the commonest as well as one of the - handsomest of American shells. It is a Floridian species, found in - shallow water and on sandy bottoms. The animal greatly resembles - that [pg380] of /Dolium/, except that it has two side-flaps, - which, when extended, partially inclose the shell. The shell is - thin, with an almost flat spire and a greatly enlarged body-whorl. - The aperture is flaring, and is drawn out anteriorly into a - tapering canal, which gives to the shell the outlines of a pear. - The ornamentation is revolving, but not highly raised, and there - are ribs with very distinct longitudinal lines of growth between. - The color is pure white, or sometimes yellowish, with rufous spots; - within it is golden. This attractive shell is usually from three to - four inches in length, but is sometimes found considerably larger. - (Plate LXXI.) - - -FAMILY ~CASSIDIDAE~ - - -GENUS ^Cassis^ - -The cassides, commonly known as the "helmet-shells," are carnivorous -mollusks, which lead an active life in sandy stations, prowling -about in search of bivalves, upon which they prey. They have a large -siphon and a fairly large and extensible proboscis. The foot is -broad and strong, being well adapted for plowing through the sand. -The shell of /Cassis/ is large, generally heavy and inflated, with -a short spire and a short, recurved anterior canal. The lip is much -thickened. Upon the Atlantic coast of North America there are four -species of /Cassis/. They are all properly West Indian in their -faunal relations, but have found lodgment on the American shore at -various points. All of them have been taken in the neighborhood of -Cape Hatteras, two of them in West Florida, and two in Texas. - - ^C. tuberosa.^ A large, heavy shell, often from six to eight inches - in length, with a flattened spire. The aperture is long and narrow, - with large white teeth upon the outer lip, which is also greatly - thickened. The columellar lip is ribbed. A heavy deposit of enamel - to the left of the columellar lip gives the shell a triangular - outline. A row of very large nodes upon the shoulder of the - body-whorl and two rows of obsolete nodes below are characteristic - features of this species. The color is light yellowish-brown - suffused with pink. The aperture and the columellar callosity are - flesh-tinted, with chestnut trimmings. The anterior canal is deep - and recurved. - - ^C. cameo.^ A species of about the same size as the last, but - more ovate or ventricose in form. It is coarsely striated, with - elevated growth-lines, and has circling rows of large, rib-like - elevations, having sometimes nodes upon the body-whorl. The - columella is conspicuously ribbed and greatly expanded. The outer - lip is thickened, and has lamelliform teeth within. Flesh-colored; - teeth white; purple-brown trimmings. A great many of these shells - are sent yearly from Nassau [pg381] to Italy, where they are used - in cameo-cutting. It is owing to the fact that the substance of - these shells is deposited in layers of different colors that they - are available for this purpose. There are about fifty species of - helmet-shells, the one most valued for cameo-cutting being known as - the black helmet, /C. Madagascarensis/. - - ^C. testiculus.^ A species found outside of the West Indies only - at Key West and at Hatteras, where the Gulf Stream has brought so - many West Indian forms, and left them at the point where it takes - its oblique course away from the shore. This pretty species is - smaller than the others just described. It has a low, depressed - spire; longitudinal ribs crossing wide, flat revolving ribs; a - long, narrow aperture; and a reflexed and thickened outer lip, - also toothed. The columella is thickened and ribbed. The anterior - canal is recurved over the back of the shell, as is usual in the - genus. The color is bluish, with dark spots. There are square black - spots on the reflexed lip; the aperture is pink, and the teeth - and columellar ribs white. This species is exceedingly common at - Nassau, and plays havoc with the more slowly moving bivalves, which - it devours. (Plate LXXI.) - - ^C. inflata.^ Perhaps the commonest species of /Cassis/ on our - coast. It is reported to be common at Beaufort, South Carolina, yet - it is not so frequently met with out of the West Indies as some - earlier collectors would have us believe. Beach-worn specimens, - however, are not unusual all along the Florida coast. It attains - a size of from three to four inches, and is a rounded, globose, - ventricose shell, with a higher spire than is usual in this - genus. The surface is almost smooth, the series of revolving ribs - being scarcely raised on the body-whorl. The lip is thickened - and reflexed, with prominent lamelliform teeth which continue as - internal ribs. The lower portion of the columella is calloused and - roughly granulated. The color is bluish-white, glazed, with large - square brown spots. The region of the aperture is pure white. - The collector should not remain content with a specimen or two - of the poor beach-worn shells of this species. In general, this - advice applies to the collection of all specimens. One can get - no idea of the sculpturing and painting of shells from dead and - worn specimens. It is quality rather than quantity that makes an - interesting cabinet. (Plate LXXI.) - - -FAMILY ~MURICIDAE~ - - -SUBFAMILY ~MURICINAE~ - -It seems like making a long leap to pass suddenly from the -/Cassididae/ to the /Muricidae/. In the natural biological order, as -it appears in our present state of knowledge, a host of families and -genera intervene between these two. But they are omitted here, either -because they do not conspicuously occur upon our own shores, or -because they are free-swimming pelagic mollusks, which live only far -out at sea and rarely are found on the beaches. The family /Muricidae/ -is an exceedingly large one, including a [pg382] bewildering number -of well-characterized genera. It has many representatives in every -sea, but, as is apt to be the case, the finest and most striking -species are tropical. The animal is not peculiar in any way, being -altogether a conventional prosobranch gasteropod, with moderately -long foot, and the usual tentacles placed upon a small head. There is -a retractile proboscis, which suggests carnivorous habits. In reality -the /Muricidae/ are perfect pirates among the /Mollusca/, attacking -nearly every species they encounter, piercing its shell and devouring -the unfortunate inhabitant. They live in rocky and gravelly places or -about coral reefs. Their shells are seldom colored, except about the -aperture. What the shells lack in color, however, they fully gain in -oddness of form and in sculpturing. The anterior canal varies from a -mere notch to an astonishingly long channel. The tendency to nodes, -varices, spires, and varicose processes in general is a prominent -feature of the family. - -There are several genera, with numerous species, upon the east and -west coasts of the United States, but we can do no more here than -mention those which are very common. - - -GENUS ^Murex^ - -Of this tropical genus there are two Floridian species--/M. rufus/ -and /M. pomum/. The genus has been very extensively divided into -subgenera, based upon shell-characters alone. Some of these subgenera -are usually accepted at full generic value, and their substitution -for the old, well-established name /Murex/ is to be expected. These -two Floridian species fall within different subgeneric lines, and the -student who goes to a museum to compare his catch with the labeled -specimens on exhibition will probably be puzzled to find his two -murices named /Chicoreus rufus/ and /Phyllonotus pomum/ respectively. -But for our purposes the name /Murex/ will do well enough. - - ^M. rufus.^ This species scarcely ever exceeds three inches - in length. Its spire is moderately high, and the aperture is - oblong-ovate, with a long, slightly curved, and almost completely - inclosed anterior canal. Through the end of this the fleshy siphon - projects in life. The shell is most extravagantly sculptured--so - intricately that it is difficult to [pg383] describe it. Its - most conspicuous feature is the large foliaceous varices which - cross the whorls, projecting almost one fourth of an inch from the - body of the shell. Between each of these varices is a large node. - There is, besides all this, a system of pronounced revolving ribs - which cross the varices and nodes, giving to the shell a greatly - roughened appearance. The interior is bluish-white. The operculum - is corneous, with a subterminal nucleus. Unfortunately, this really - handsome shell is usually incrusted with coralline or calcareous - matter, which must be removed with acid before a good idea of - its appearance can be had. In color it is reddish-brown to dark - chestnut on the varices. It is very common on the west coast of - Florida, but rarer elsewhere. (Plate LXXII.) - - [Illustration: PLATE LXXI. Dolium galea. Dolium perdix. - - Pyrula papyratia. - - Cassis testiculus. Cassis inflata.] - - [Illustration: PLATE LXXII. Murex rufus. Murex pomum. Ocinebra - poulsoni, enlarged. Pteronotus festivus. Cerostoma foliatum. - Cerostoma nuttallii.] - - ^M. pomum.^ A more abundant species, found all along the coast - from Hatteras to Texas. It is not so elongated as the last, and - its sculptural design is much less exaggerated. Between each of - the varices are two nodules. The aperture is oblong-ovate, and - the anterior canal is nearly closed and recurved toward the back. - Revolving ribs cross the varices and nodules. The color is ashen, - with chestnut tips upon the nodes and varices, and chestnut-colored - patches about the aperture. The varices are simple and not - foliaceous as in /M. rufus/; the shell is more globose. Length two - to three inches. (Plate LXXII.) - - ^M. (Phyllonotus) fulvescens.^ The largest of the American murices. - It is not commonly found except in Texas. - - -GENUS ^Trophon^ - -[Illustration: /Trophon clathratus./] - - ^T. clathratus.^ A fairly common shell of the Maine coast; - although it belongs to a deeper zone than that of the tides, it - is occasionally found after storms upon the shore. It is a small - fusiform shell, with many prominent longitudinal ribs and a - produced anterior canal. /Trophon/ is a boreal genus, which finds - the best conditions for life in the icy waters of Labrador and - Greenland. - - -GENUS ^Urosalpinx^ - -The genus /Urosalpinx/ is closely allied to /Murex/ and /Trophon/. -Several of its species are found on the east coast of the United -States. - -[Illustration: /Urosalpinx cinerea./] - - ^U. cinerea.^ This well-known species is regarded by Chesapeake and - Long Island Sound oystermen much in the light of a plague. These - active predaceous mollusks live upon bivalves, and preferably upon - oysters. They bore a small round hole through the shell of their - helpless victims, and then proceed to extract the succulent, fleshy - animal from within. The oystermen call them by the suggestive - name of "drill," and wage incessant warfare upon them. In some - years these mollusks appear to go into partnership with the large - starfish, /Asterias/, and the combination of the two can soon - destroy any oyster-bed. The original home of this destructive - little creature is presumed to be in Chesapeake [pg384] Bay, but - the transplanting of oyster-spat thence to Long Island Sound has - introduced the enemy at the same time. The species has a wide range - from Florida to Cape Cod, and locally north of that point; in fact, - it may be counted upon to appear wherever there are oyster-beds. - The shell is dingy gray in color, and its whorls are crossed by a - dozen or more rib-like undulations, and numerous revolving striae. - The anterior canal is produced, and is yellowish-brown within. - Length under an inch. - - -GENUS ^Eupleura^ - - ^E. caudata.^ A curiously flattened shell which has close family - connections with that last described. The peculiarly flat - appearance is due to the fact that there is a rather wide varix - upon each side of the shell. It is a small species, never more than - an inch in length, dingy gray, with longitudinal undulations upon - the whorls, and a long, narrow anterior canal and crenulated lip. - The animal is white and yellow, and is notable for its activity. - Found from Maine to Florida, about low-tide mark. - -[Illustration: /Eupleura caudata./] - -On the west coast of the United States occurs a striking development -of a group of the /Muricidae/ of a curious foliaceous appearance, -belonging to the genera /Pteronotus/, /Ocinebra/, and /Cerostoma/. - - -GENUS ^Pteronotus^ - - ^P. festivus.^ The shell is marked by three well-raised varices - upon each whorl, which are reflexed backward; between each varix - is a rounded knob. All is covered with numerous spiral lines - of sculpture, which upon crossing the varices are frilled. The - aperture is oval and white within; the anterior canal is entirely - closed and is reflexed slightly over the back. Length two inches; - color dingy white. Found on the southern coast of California. - (Plate LXXII.) - - -GENUS ^Ocinebra^ - - ^O. poulsoni.^ This has the same dingy white color as the species - last described. Its plan of sculpturing is somewhat different and - consists of a series of rounded varices, about nine to a whorl, - crossed by spiral lines. The anterior canal is open, and just - within the white aperture, upon the inner side of the lip, is a - series of five or six little round teeth. This species frequents - the waters near San Diego, and sometimes grows to be two inches in - length. (Plate LXXII.) - - ^O. lurida.^ A much smaller species than the last, being not more - than one half to three fourths of an inch in length. Very common - at Monterey and in San Francisco Bay. It is strongly marked with - spiral lines covering the longitudinal undulations usually found in - this genus, but which are less prominently developed in this case. - - There are several species of small ocinebras upon the California - coast, but they are not easily determined without a more critical - examination [pg385] than we are giving our specimens. They are - ^O. interfossa^, a small shell with deep spiral grooves, sharp - varices, and deep sutures; and ^O. circumtexta^, also small, but - heavy, short-spired, with scalloped or crenulated outer lip. - - -GENUS ^Cerostoma^ - - ^C. nuttallii.^ A species belonging to the southern coast of - California. It may be recognized at once by two prominent - characters: first, a horn-like projection from near the base of the - outer lip, and, second, the tumid varices alternating with rounded - knobs. It has no spiral series of lines like those in /Pteronotus - festivus/; and it has a row of five or six little teeth upon the - inner side of the aperture, like those in /Ocinebra poulsoni/. - The anterior canal is closed. It is about two inches long. (Plate - LXXII.) - - ^C. foliatum.^ A shell somewhat like the last, but almost twice as - large, with heavy wing-like varices (three upon each whorl), made - up of overlapping plaits. The knobs between the varices are much - smaller, while the revolving ribs, though fewer in number than in - most of these west-coast murices, are heavy and large. The aperture - is oblong, the anterior canal closed. There is a "horn" near the - base of the aperture, as in /C. nuttallii/, but no row of teeth - upon the under side of the lip. The color is dingy white. (Plate - LXXII.) - - In the waters of Oregon and Washington there are a few trophons and - other forms similar to the east-coast genera. These no doubt belong - to the boreal and arctic faunal provinces, and have spread over - both the Atlantic and Pacific northern regions. - - -SUBFAMILY ~PURPURINAE~ - -This is considered a subfamily of the /Muricidae/, and the group -therefore bears the subfamily termination /-inae/. There is no vital -difference between it and the subfamily /Muricinae/. The operculum in -the /Purpurinae/ has a lateral nucleus instead of a subterminal one, -but beyond this there are no essential differences. The shell of the -purpuras is generally heavy and solid, being adapted to a life among -rocks which are exposed to the beating of the surf. There is a lack -of that extravagant sculptural design so characteristic of the true -murices, most of the purpuras being comparatively smooth, in order, -no doubt, that they may offer as little resistance as possible to the -rushing, seething waters of exposed rocky shores. - -The /Purpurinae/, like some of the murices, when mutilated, exude a -reddish-purple fluid. On account of this, the ancient Romans used to -gather great quantities of certain Mediterranean forms belonging to -these families, place them in large mortars, [pg386] and grind them -up, shell and all. A garment dipped in the mixture and then exposed -to the sun would receive a rich purple dye. This was the basis of the -famous "Tyrian purple." The process was lost, and was rediscovered -many centuries later, but it was long ago abandoned in favor of the -far superior modern chemical dyes. - - -GENUS ^Purpura^ - -[Illustration: /Purpura lapillus./] - -[Illustration: The same; a younger specimen.] - - ^P. lapillus.^ No one who has ever spent an observant hour among - the rocks at low tide, on the shores of Massachusetts or Maine, - has failed to notice the myriads of /P. lapillus/ clinging to - the barnacle-covered boulders, or slowly creeping about in the - tide-pools. This rather pretty little mollusk is a native of Great - Britain, and there attains its greatest development and exhibits - best its marvelous range of variation. It is presumed to be an - immigrant in American waters, having found its way across the sea - by Iceland and Greenland, and thence down the coast. As it is a - cold-water animal, and can only survive in open, rocky stations, - it will probably never pass south of New York. It is difficult - to describe this well-known species because it is so extremely - variable. There is an individuality about the species which causes - it to be recognized at once, yet its details are elusive. It is - never more than one and a half inches long (in the United States), - and varies in color from white through yellow to chocolate. Often - it is banded in yellow or brown. Near the only sand-beach of Bar - Harbor is a colony with vermilion bands. The shell varies from a - smooth to an exceedingly rough exterior, the latter being caused by - raised scales along the lines of growth, which make the shell even - prickly to the touch. Of this latter form there is a large colony - on Campobello Island. Numerous coarse revolving ridges are common. - The columella is flattened and smooth, and its lower portion is - a little twisted. The anterior canal is short. /P. lapillus/ has - been accused of attacking clams and boring their shells, as does - the predaceous /Urosalpinx cinerea/, but the accusation is not well - founded. /Purpura/ is carnivorous, and no doubt destroys many young - barnacles; but with its short and small foot it would find great - difficulty in digging in the sand for clams. - - In Florida waters there are several purpuras, which properly belong - to the West Indian fauna, but enjoy an extensive range. - - ^P. patula.^ This species has a rounded body-whorl, and sometimes a - low spire, which give it much the appearance of a large limpet. Its - back is decorated with rows of nodules in regular order, forming - a spiral series. The chief point of distinction is the deeply - excavated, broadened, and flattened columella-lip of salmon-color. - A portion of the whorl itself is worn down and made smooth by being - dragged over sharp coral rocks, revealing underneath the rough, - incrusted exterior, a transparent colorless shelly substance. Dark - and chestnut-colored [pg387] patches and spots adorn the outer - lip. The shell is from two to two and a half inches long. (Plate - LXXIII.) - - ^P. haemastoma.^ Like its relative, /P. lapillus/ of Northern - waters, this species is so variable as almost to defy description. - The form that usually occurs from Hatteras to Florida is of a - bluish-gray color, and is indistinctly encircled with narrow yellow - zones, which are crossed by somewhat vague longitudinal waves of - black. The columella and outer lip and interior are orange-yellow. - The spire is moderately high, with a sharp apex. The whorls are - noduled upon the shoulder. There are revolving grooves throughout, - even within the aperture. A Texan variety of this species has - a much more elevated spire, with channeled sutures, and small - aperture of bright salmon-color. - - Upon the Californian coast there are three species of /Purpura/, - which markedly resemble the /P. lapillus/ of the Maine shores. - Their extreme variability has given rise to much confusion in their - nomenclature; the multitude of names given by numerous authors to - the varietal forms of these three species constitute a list of - synonyms which is appalling to the systematic student. - - ^P. crispata.^ With very few modifications, a description of /P. - lapillus/ would apply to this species, which occurs commonly at San - Francisco and ranges north. /Crispata/ is possibly heavier, with a - smaller aperture, and with four or five round teeth upon the inner - white surface of the thickened outer lip. It ranges in color from - pure white to dark brown and is sometimes banded. The surface may - be smooth or rough, and is sometimes ruffled all over with wrinkled - frills. Length one and a half inches. Its habits and station are - much the same as those of /P. lapillus/, of which it is possibly - a descendant, somewhat modified by changed environment. (Plate - LXXIII.) - - ^P. lima.^ A less common species, with rounded whorls and channeled - suture, and about fifteen spiral grooves upon the whorls. The color - is light brown; the length from one quarter of an inch to one inch. - - ^P. saxicola.^ A shell exceedingly abundant along the whole - Californian coast, living under quite the same conditions as the - purpuras already described. It is smaller than the last two, being - always less than an inch in length. It also runs through the gamut - of variations as to color-scheme and sculpturing, but always - preserves a certain individuality. There is a tendency to a small - umbilicus; the outer lip is sharp; the columella is flattened and - slightly twisted; and anterior canal is short, and bears to the - left. A smaller aperture, with relatively thicker shell, seems to - be all that distinguishes it from the smaller varieties of the - east-coast species. (Plate LXXIII.) - - -GENUS ^Monoceras^ - -This genus, which is very closely allied to /Purpura/, is almost -wholly confined to the west coast of the United States. The name is -given on account of a peculiarity, which has, however, already been -noticed in /Cerostoma/, namely, a horn-like projection from the basal -portion of the outer lip. In all other respects this genus is nothing -but a true /Purpura/. [pg388] - - ^M. lapilloides.^ The shell in this species is about an inch in - length, and has markings which give it a striking resemblance to - granite. A row of small round denticles upon the inner surface - of the lip is a characteristic already noticed in some of the - west-coast murices. Their station is the same as that of the - purpuras--between the tides on rocky, exposed shores. (Plate - LXXIII.) - - ^M. engonatum.^ This species has sharply ridged whorls, and - revolving ribs with wavy growth-lines between them. In other - respects it is almost identical with the last described. It is - often found mingled with the seaweed which covers rocks between - tides, and, when moist, simulates the color of its surroundings. - (Plate LXXIII.) - - -GENUS ^Chorus^ - - ^C. belcheri.^ This family cannot well be left without at least - a mention of this large and rather handsome species. /Chorus/ is - a genus of but few species, confined to the Pacific shores of - North and South America. This particular species does not reach as - far north as San Francisco, but may be taken at low tide in the - vicinity of San Diego. The prominent feature of the shell is the - posterior canal, which, being abandoned as the growth of the shell - continues, leaves a series of hollow, folded spiny processes upon - the shoulder of the body-whorl, which appear like jagged points - upon the spire. (Plate LXXIII.) - - -FAMILY ~COLUMBELLIDAE~ - -This is a large family of small but often exceedingly beautiful -shells. Their distribution is mostly tropical, but the list of -North American species is a very generous one indeed if the -deeper-water forms are included. The animal is quite the same as in -the /Buccinidae/, to be described later. (See also description of -/Buccinum undatum/ on page 330.) The shells are usually quite solid, -with a long, narrow slit for an aperture; the outer lip is thickened -on the inside, especially about the middle portion, and is deeply -toothed; and the lower portion of the columellar lip is also ribbed -or toothed. - - -GENUS ^Columbella^ - - ^C. mercatoria.^ This Antillean species is found in Florida, and - is one of the gems among the American shallow-water shells. Its - height is about one half of an inch. It is decorated with revolving - grooves and with a variously patterned color-scheme of broken - yellow or reddish [pg389] lines on a white background, or of - white splotches on a brownish background. (Plate LXXIV.) - - [Illustration: PLATE LXXIII. 1, Purpura patula. 4, Monoceras - lapilloides. 2, Purpura crispata. 5, Monoceras engonatum. 3, - Purpura saxicola, enlarged. 6, Chorus belcheri.] - - [Illustration: PLATE LXXIV. 1, Columbella mercatoria, enlarged. - 4, Nassa fossata, about natural size. 2, Columbella (Amphissa) - corrugata, enlarged. 5, Nassa mendica, enlarged. 3, Columbella - (Astyris) gausapata, much enlarged. 6, Nassa perpinguis, enlarged. - 7, Nassa tegula, enlarged. 8, Siphonalia kellettii, reduced. 9, - Tritonidea tincta.] - - ^C. (Anachis) avara^, and the variety ^C. similis^. These rather - slender shells, about one half to three fifths of an inch long, - occur from Florida northward to Cape Cod. The upper whorls are - smooth, the lower ones are undulated with vertical costae (ten - to thirteen), and the body-whorl is encircled below the middle - by a series of revolving, closely set grooves. The aperture is - typical of the genus, though less strongly marked by internal - callosity on the outer lip and with less prominent teeth than in - /C. mercatoria/. The greater development of the revolving grooves, - which spread over the entire surface of the body-whorl and cross - the costae, producing a granulated surface, constitutes the variety - /C. similis/. The color is brownish, with white reticulations. - This species is to be found in considerable abundance in sandy mud - and among stones and algae about low-water mark. At New Bedford and - Martha's Vineyard, and on Cape Cod, it may always be taken. It is - also common at Norfolk and along the Virginia and Georgia coasts. - - ^C. (Astyris) lunata.^ One of the characteristic eastern-coast - shells, which, like the last species, ranges from Cape Ann in - Massachusetts to the West Indies. It occurs about low-tide mark - and just below, upon stones and algae, or crawling about on a soft - bottom. On account of its generic features, combined with the - peculiar coloration, the species cannot be mistaken. The latter is - a ground of reddish-brown or fawn, with encircling rows of large - white or yellowish spots. The whorls are quite smooth. Length not - over one fifth of an inch. - - The collector soon learns to recognize the variable forms of - these northern-range columbellas. They are not a difficult group, - for once their generic position is established by the characters - of the aperture (which are constant) the species can readily be - determined, notwithstanding their tendencies to vary from the type. - Californian waters also have several columbellas. The conchologists - of the west coast have preferred to apply to their shells, and - indeed to employ in general use, a large number of subgeneric names - in place of the ordinarily accepted generic ones. The result of - this is to confuse at first the student of conchology, who, though - fairly familiar with the molluscan genera, finds himself perplexed - when he confronts a list of west-coast shells. Thus the two common - Californian columbellas are /"Amphissa" corrugata/ and /"Astyris" - gausapata/, these two species belonging to different subgenera of - the genus /Columbella/. - - ^C. corrugata.^ This shell finds its metropolis in Puget Sound, - but occurs also along the Californian shore. The aperture is wider - than is usual in this genus. The surface is deeply wrinkled by - longitudinal costae and is encircled by revolving grooves. Length - one half of an inch; color red, or orange to light brown. It is - found in shallow protected waters. (Plate LXXIV.) - - ^C. gausapata.^ This species lives in great numbers about the roots - of eel-grass. It is very small and smooth, with a rather high - spire. The color of the spire is deep brown; the body-whorl is - lighter in color. Occasionally the body-whorl is obtusely carinated - just below the suture. This little shell is very common upon many - beaches after heavy winds, but it should be sought for at very low - tides and gathered alive. (Plate LXXIV.) [pg390] - - -FAMILY ~NASSIDAE~ - -These are familiar, and often very characteristic, littoral shells in -all parts of the world. Where they exist at all they are generally -to be found in astonishingly large numbers, sometimes even crowding -out all other mollusks. They are exceedingly active and predaceous, -feeding upon other mollusks, whose shells they bore through by means -of the sharp teeth upon their lingual ribbon. The /Nassidae/ of the -east coast find a relentless enemy in the small hermit-crabs, which -attack them, drag them from their coverings, and then proceed to -occupy the empty shells themselves; the torn and lacerated /Nassa/ -animal is thereupon leisurely eaten, a retribution probably well -deserved. The animal of /Nassa/ (the principal genus of /Nassidae/) -is peculiar in having frequently a bifurcated tail; or, to speak -more correctly, the posterior end of the foot is terminated by two -appendices. It has a long siphon, and eyes placed upon the outer -sides and near the base of the tentacles. The operculum has serrated -edges. - - -GENUS ^Nassa^ - -[Illustration:/Nassa trivittata/, showing the animal as if crawling.] - -[Illustration: /Nassa trivittata./] - - ^N. trivittata^, ^N. obsoleta^. These are the two nassas of the - New England and New Jersey coasts. The first has a more northerly - range, extending to the Gulf of St. Lawrence; the other is not - usually found north of Cape Cod, but below that point as far as - Hatteras it is probably the commonest shell of the coast. It fairly - swarms in sheltered muddy reaches about low tide. Little pools left - by the tide on the Jersey flats are sometimes so crowded with /N. - obsoleta/ that for lack of room the animals crawl over one another. - /N. trivittata/ is more commonly taken at small depths in the - harbors, where it seems to live well upon all kinds of sea-bottom. - Probably they exist in great numbers along the southern shore of - Long Island, for the beaches are often lined with their dead and - worn shells. Over half the specimens thus found will have a little - round perforation upon some whorl, showing that they were victims - of some cannibalistic brother. The shells of the /Nassidae/ have a - short, ovate aperture, with a short anterior canal. The inner lip - is smooth, and is usually coated over with a more or less heavy - [pg391] deposit of enamel. /N. trivittata/ is about one half to - seven tenths of an inch long, and is yellowish-white. A series of - revolving grooves cutting across a series of longitudinal lines - gives the shell a decussated or granulated appearance. The whorls - are somewhat shouldered at the sutures, and are white inside. - /N. obsoleta/ cannot be called a handsome shell by the most - enthusiastic collector. Its spire is usually eroded or completely - dissolved away. The color is blackish to olive, with the aperture - purplish-black. The columellar lip is arched, with a twist or - fold in its lower portion. It is decussated by crossing lines and - grooves, though not so conspicuously as /N. trivittata/; sutures - simple; length one half of an inch to one inch. Old specimens not - only become eroded, but are usually covered with vegetable mould, - and are not over-inspiring to the collector. They often live in - brackish water, and frequent all the inlets and marine flats - between Cape Cod and Hatteras. Below Hatteras both this and the - last-named species occur, though not so plentifully. - -[Illustration: /Nassa obsoleta./] - - ^N. vibex.^ This ubiquitous little mollusk seems content in any - station, and swarms in all the sandy bays of Florida. It is a - busybody, always on the move, and its long siphon is constantly - vibrating. The shell is about one half an inch long and shining - white, with brown or reddish spots. There are prominent - longitudinal undulations and revolving lines upon the lower part of - the body-whorl. The anterior canal is deeply cut and very short; - the columellar lip arched, richly calloused, and often granulated - at its base. This is probably the first live shell the collector in - Florida will encounter. The animal is very graceful and prettily - marked in color. The terminal cirri on the foot form a notable - feature--a character belonging to the entire family. - -[Illustration: /Nassa vibex./] - - ^N. fossata^, ^N. perpinguis^. On the California coast there are - the huge (for this genus) /N. fossata/ and the smaller but no less - interesting /N. perpinguis/, also ^N. tegula^ and ^N. mendica^. - /N. fossata/ grows to a length of one and a half to two inches. - When adult the lip is somewhat thickened, and the entire aperture - is bright orange. The color of the shell is ashen-gray, and it - is marked with spiral and transverse riblets which produce a - granulated surface, especially upon the upper whorls. The shell is - ribbed inside the mouth. A deep groove circles the anterior canal - at the base of the body-whorl. /N. perpinguis/ is an especially - graceful shell, smaller than the last-named and more finely - decussated and darker (brown) in color. It also has a deeply - channeled groove encircling the base of the body-whorl. It is - often banded in chestnut. Both these species occur in the southern - part of California only; /N. tegula/ and /N. mendica/ are of more - northern range. The former resembles the Floridian /N. vibex/. /N. - mendica/ is a slender shell three quarters of an inch long, with - prominent longitudinal ridges, and light brown in color, with a - white aperture. (Plate LXXIV.) - - -FAMILY ~BUCCINIDAE~ - -From the number of subfamilies and genera included in this -exceedingly large and comprehensive family, it would almost [pg392] -seem that it has served as a sort of dumping-ground for various -groups of mollusks of uncertain biological affinities. Although the -family has recently been reduced by the removal of several large -families, it still remains a bulky one. - - -GENUS ^Buccinum^ - -The animal is described at some length on page 330. It has no -striking peculiarities. The siphon in /Buccinum/ is fairly long; the -eyes are placed about midway between the base and the end of the -tentacles. It is in general a conventional prosobranch animal. The -great majority of the members of this family have a boreal range and -are found widely distributed within the colder waters of the world. - - ^B. undatum.^ This is the most prominent representative of the - /Buccinidae/ upon the North Atlantic shores of the United States. - It is an exceedingly common shell, ranging from Cape Cod to - Greenland. It is also found in England and Scotland, where it is - extensively used as food under the familiar name of "whelk." It - affects every kind of station and seems to be as much at home in - very considerable depths as about the low-tide mark. Upon the Maine - coast it may be found almost everywhere, just below low tide. If - none are in sight they may be attracted by putting a dead fish - in a basket and anchoring it near shore. The American whelk is - somewhat smaller than the British variety, although it attains a - length of full three inches. It has revolving ribs and longitudinal - oblique folds. A yellowish-brown, velvety epidermis covers the - entire shell. The lip is simple, and the shell is white or golden - yellow within. The columella is somewhat twisted; the operculum - is corneous, with a lateral nucleus. The variations in this shell - are so great as to have caused naturalists no little perplexity. - Specimens taken near large cities are apt to be defective. (Plate - I.) - -[Illustration: /Buccinum undatum./] - - -GENUS ^Chrysodomus^ - - ^C. decemcostatus.^ One of the most striking shells of our - northeast coast. As its name indicates, it is decorated with - (normally) ten costae. [pg393] These are prominent revolving ribs - or keels upon the body-whorl, the upper one being the largest, the - others diminishing in size toward the base of the shell. Upon the - upper whorls but two of these circling keels appear. The lip is - plain, but somewhat modified by the termination of the ribs. The - columella is arched above; the canal produced (sometimes to the - left). The color without is dull ashen-white to horn; within, pure - white. The operculum is small, with a terminal nucleus. The animal - is the same as /Buccinum/. This species is not quite so common as - /B. undatum/, but it is often found associated with it. At Eastport - and Bar Harbor it is abundant just below low-water mark. - -[Illustration: /Chrysodomus decemcostatus./] - - -GENUS ^Sipho^ - -[Illustration: /Sipho Stimpsoni./] - - ^S. Stimpsoni.^ One of the most graceful of the larger shells of - our eastern coast. It is almost identical with the /S. islandicus/ - of northern European waters, and for a long time was considered to - be the same species. /S. Stimpsoni/ is not found south of Cape Cod, - except possibly in deep offshore stations. North of that point it - ranges to Newfoundland, but it has enjoyed the reputation of being - a rare shell and has been greatly prized by local collectors in - consequence. It is, in fact, not rare to any one who is provided - with a dredge and rope enough to enable him to use [pg394] it - effectively in from twenty to one hundred feet of water. The spire - is high and regular, with seven to eight slightly rounded whorls. - The suture is simple, and there are faint revolving grooves. The - epidermis is thick, horn-colored, and sometimes velvety; the lip - simple; and the anterior canal produced. The shell is pure white - within. The operculum is corneous, with a subterminal nucleus. The - animal is the same as /Buccinum/, but with small irregular specks - of black. This shell is found from three to five inches long. - -[Illustration: /Sipho pygmaeus./] - - ^S. pygmaeus.^ This species has the same range as that of the - species just described, and often occurs associated with the young - of the latter. It may be distinguished from /S. Stimpsoni/ by the - greater number of whorls, the more prominent revolving ridges, and - the smaller aperture. The epidermis is drab-colored and strongly - corrugated, inclined to hirsute. The color of the shell is pure - white. Length one inch to one and a half inches. It is found from - low-tide mark to very considerable depths. - - -GENUS ^Siphonalia^ - - ^S. kellettii.^ /Siphonalia/ is one of the Pacific genera of the - /Buccinidae/, which finds its greatest development in Japanese - waters. One of these Japanese species, /S. kellettii/, is also - found in California. It has the typical animal of the /Buccinidae/, - and a fusiform shell white to brownish in color, and three to five - inches in length. It is conspicuously marked upon the whorls by a - revolving series of large rounded knobs and indistinct revolving - grooves. The operculum is corneous, the nucleus subterminal. It is - found in shallow water to low-tide mark. (Plate LXXIV.) - - -GENUS ^Tritonidea^ - - ^T. tincta.^ A Floridian species which ranges from Hatteras to - the West Indies, and finds its station near low-tide mark, upon - coralline rock or rough, stony bottom. It is about one inch in - length, is of a brownish horn-color, and has an oval aperture with - a crenulated outer lip and a deep anterior canal. An entering ridge - of white enamel at the top of the columellar lip forms, with one of - the teeth of the outer lip, a posterior canal. It is sculptured, - with revolving ridges and crossing longitudinal folds. The color - is bluish-white within the shell, touched with yellow about the - anterior canal and along the edge of the outer lip. (Plate LXXIV.) - - -FAMILY ~TURBINELLIDAE~ - - -GENUS /Fulgur/ - -Of the two genera of this family which occur in American waters, -/Fulgur/ may be taken as the most characteristic mollusk of the -American Atlantic fauna; that is to say, /Fulgur/ occurs only on -the American east coast. Its range is from Cape Cod to the West -Indies. The two Northern species are /F. carica/ and [pg395] /F. -canaliculata/, both of which are exceedingly common in sandy shore -stations from Cape Cod southward. - -[Illustration: /Fulgur carica./] - - ^F. carica.^ The largest univalve north of Hatteras, most easily - recognized by its pear-shaped shell, with simple suture and - brilliant vermilion aperture. The anterior canal is long and - open; the columellar lip is twisted and arched, and the outer - lip is simple. There is a revolving row of nodes or spines of - various degrees of prominence upon the shoulder of the body-whorl, - continued on the spiral whorls just above the suture. The color - varies from ashen-gray to a dirty brown. In young specimens there - are stripes and bands of violaceous brown, and the shells are - striate within the aperture. The length of this shell is sometimes - nine inches. - - ^F. carica^ frequents almost any sort of bottom. In Long Island - Sound they are common on stony ground, but they do not attain - the maximum size and the high degree of aperture-coloration - characteristic of those taken along the New Jersey shore, on sandy - stations exposed to the surf. The string of curiously shaped - capsules containing the eggs of /Fulgur/ is shown in Plate I. - -[Illustration: /Fulgur canaliculata./] - - ^F. canaliculata^ often occurs associated with the last. It does - not attain quite the same size, but specimens of both species - are, on the [pg396] average, about equal in cubic capacity. It - is pear-shaped, like /F. carica/, and has a long anterior canal; - but its distinguishing features are the flattened shoulder of the - whorls and the deeply channeled sutures. The epidermis is brown, - thick, and heavy. The color of the shell is whitish-gray, yellowish - within. It is found in the same places as /F. carica/, and is very - abundant at Atlantic City and along the entire New Jersey coast. - - ^F. perversa.^ A Floridian species, immediately recognizable by the - fact that it is sinistral; otherwise a description of the shell - would almost fit that of /F. carica/, except in the matter of the - color of the aperture, which in /F. perversa/ is brownish-white. - The brownish streaks upon the whorls, in young specimens, are - a very noticeable feature of this shell. The shoulders of the - whorls are rather flatter than in /F. carica/, but, unlike /F. - canaliculata/, the sutures are simple. The row of nodes or rounded - spines which encircles the body-whorl appears in the spire as nodes - just above the sutures. The animal is jet-black, and frequents - sandy flats, where, at low tide, it may be gathered in considerable - numbers, as it plows its way along, almost wholly concealed beneath - the sand. Large specimens measure quite a foot in length. In old - shells the color-markings are not so brilliant, the shells being a - dull, lusterless white. (Plate LXXV.) - - ^F. pyrum.^ Another Floridian species, much smaller than the last - (three to four inches), with a regular, pear-shaped outline, a long - anterior canal, a low spire, deeply channeled sutures, flattened - shoulders, and no spinous or nodose processes. It is ornamented - with revolving inconspicuous ribs or striae, alternately larger, - and has a somewhat hirsute epidermis. The color is white, with - transverse broad yellowish or rusty lines; the color within the - aperture resembles that of the exterior color-lines. It is found on - sandy stations, in shallow water. (Plate LXXV.) - - -GENUS ^Melongena^ - - ^M. corona.^ A Floridian species, named from the single or double - row of spinous processes upon the shoulder of the body-whorl and - the crenulated appearance of the spire caused by the continuations - of the triangular spines. The three apical whorls are not spinous. - There is also a row of hollow triangular spines obliquely - encircling the base of the shell. The epidermis is heavy, rough, - and brown; the aperture oval and large; the outer lip notched at - points where the spines commence; the anterior canal wide and - short; and the columella white and twisted, and banded within with - purplish-chestnut and white. The color without is drab in older - specimens, in young specimens chestnut banded with revolving striae. - Length four inches. Found in shallow water. This active predaceous - animal must be the terror of the mollusks in Florida. With his - sharply toothed radula he is able to pierce even the ponderous - clam-shell, /Venus mercenaria/, variety /mortoni/, and devour the - soft fleshy parts within. No mollusk, save, perhaps, the vigorous - /Strombus pugilis/, can escape the attack of this highwayman. - (Plate LXXV.) - -[Illustration: PLATE LXXV. Fulgur perversa. Melongena corona. Fulgur -pyrum.] - -[Illustration: PLATE LXXVI. Fasciolaria gigantea, very much reduced. -Fasciolaria distans. Fasciolaria tulipa.] - -[pg397] - - -FAMILY ~FASCIOLARIIDAE~ - -This family comprises a number of genera of mollusks which have a -fusiform shell, with a long-drawn-out spire and a long anterior -canal. The animal is in no manner remarkable; no essential -differences are to be noted from the usual conventional type of -gasteropod mollusk, represented in the two families last described. - - -GENUS ^Fasciolaria^ - -This genus is of tropical range, and contains many species of shells -which are more or less conspicuous for their large size or their -beauty of form. Three species occur in Floridian waters, and all -of them may be taken about low-tide mark on the sandy flats which -are so characteristic of Florida bays and harbors. All of them are -sluggish animals which crawl very slowly along the bottom or bury -themselves almost wholly in the sand, leaving only the tip of the -spire projecting slightly above. - - ^F. gigantea.^ This is said to be the largest gasteropod shell - known. It often attains a length of sixteen inches, and specimens - are reported to have been found measuring no less than two feet. - This huge mollusk has a symmetrically fusiform shell, with whorls - obtusely ridged and armed with large rounded nodes. The aperture - is reddish-brown within. The anterior canal is long and open, and - there are three "plaits," or folds, about the columella. The outer - lip is more or less sinuate, the color is fleshy-white, and the - shell is covered with a thick yellowish or chestnut epidermis. The - animal is of a brilliant scarlet color. (Plate LXXVI.) - - ^F. tulipa.^ An exceedingly common species of Floridian waters, - which may justly be classed among the "show shells" of the American - Atlantic fauna. It has a typically symmetrical, fusiform shape, - with gracefully rounded whorls, and is spirally but not deeply - grooved. The sutures are crenulated; the anterior canal is long; - there are three entering folds upon the columella; and the outer - lip is simple. The scheme of coloration is variable, but there are - two chief patterns, which are usually followed, though they often - are considerably modified. One is a light-bluish body, variegated - with chestnut or olive blotches, which are more extensive upon - the spire than upon the body-whorl; the other is a pinkish body, - encircled with revolving black lines. The specimens of /F. tulipa/, - which are found so abundantly in the shallow bays and estuaries of - the Florida coast, are, for some reason, never brightly colored, as - are those taken in the open sea. The length is about four to six - inches. (Plate LXXVI.) - - ^F. distans.^ A form almost identical with that last described. It - is much smaller, varying from two to three inches in length, lacks - the crenulations of the sutures, and is perfectly smooth, save for - a few spiral ridges about the base. The color is bluish-white, with - clouded longitudinal [pg398] streaks of olive. Encircling the - shell are from four to seven black lines. (Plate LXXVI.) - - These three species of /Fasciolaria/ often occur associated upon - sand-banks which are exposed at unusually low tides. It requires - some force to dislodge the large /F. gigantea/ from its bed of - sand. When the apex is discovered projecting an inch or less from - the bottom, the collector must scrape away the sand down to the - body-whorl, and then secure a good hold upon the spire and pull - hard. The stupid animal will not at once withdraw into his shell, - but will hang protruded from the aperture like a great piece of - vividly red meat. To extract any of these larger fasciolarias from - its shell, it is necessary to boil it for ten or fifteen minutes. - Large specimens of /F. gigantea/ should remain in the pot half an - hour. The heavy corneous epidermis of /F. gigantea/ will dry and - crumble away unless it is rubbed with vaseline about once a year. - - -FAMILY ~VOLUTIDAE~ - - -GENUS ^Voluta^ - - -[Illustration: /Voluta junonia./] - -The =Volutidae=, like the cowries, are "aristocratic" shells. As was -stated above, there are many collectors who have become so fascinated -by the shells of a few of these "first families of the /Mollusca/" -that they make great efforts and spend no small sums in seeking to -complete their cabinet series of the rare and more beautiful forms. -The /Volutidae/ certainly have very beautiful shells, and they are for -the most part exceedingly rare. The reason of their rarity has no -doubt something to do with their habits. They are probably largely -dwellers upon rocky ground, where the dredge cannot reach them. -There is but one species of /Voluta/ upon the American coasts which -is available to the shore-collector, and this is the well-known and -much-sought-after ^V. junonia^. The animal of /Voluta/ has a very -broad foot, and a head curiously divided into two lobes, upon which -are placed sessile eyes. A remarkable feature of the genus is the -lack of an operculum. [pg399] - - ^V. junonia.^ This volute has never been taken alive in shallow - water near the shore, but is occasionally found cast upon the - beach after violent storms. Sanibel Island is the best locality. - /V. junonia/ has an obtuse apex, a long aperture, and a shell - from three to three and a half inches in length. The color is - cream-white, painted with rows of large deep-red spots. In his - "American Marine Shells," published nearly thirty years ago, Mr. - Tryon says: "This is the most rare and valuable American marine - shell; specimens in good condition sell for from fifty to one - hundred dollars." A good specimen is probably not worth so much - to-day as when Mr. Tryon wrote, but it is at least worth a careful - survey of a Floridian beach after a storm. - - -FAMILY ~MARGINELLIDAE~ - - -GENUS ^Marginella^ - -This is a family of exquisite little shells. In point of beauty they -would rival the volutes were they not so much handicapped by their -small size. The largest /Marginella/ is not more than an inch and a -half in length, while the great majority of its two hundred tropical -species do not exceed one half an inch. The animal is very similar -to that of /Voluta/; indeed, the marginellas were until recently -included in the /Volutidae/. The shell is also suggestive of /Voluta/. -It is porcelanous, highly polished, and shining like all shells -which are covered by a portion of the mantle when the animal is -extended. Forty-seven species of /Marginella/ are recorded from the -Atlantic coast of the United States. The marginellas frequent sandy -or muddy sheltered spots, and may be collected between tide-marks. -In California there are several species, which are so minute that it -seems hardly worth while to attempt a description of them. They are -white and very inconspicuous little shells. One is tempted, however, -to speak of some of the fine marginellas of the Bahamas. The animals -are quite as beautifully marked as the shells themselves, while the -shell of one species is used in jewelry on account of its pearly -luster suffused with the most delicate pink. - - ^M. apicina.^ The most abundant Floridian species of this genus. It - is not more than one third of an inch long, with a depressed spire, - a large body-whorl, a long aperture nearly equaling the entire - length of the shell, a thickened outer lip, and four very prominent - plaits on the columella. The surface is smooth. The white, enlarged - outer lip is glazed or highly polished, and bluish or brown in - color, with red spots. (Plate LXXVII.) [pg400] - - -FAMILY ~OLIVIDAE~ - - -GENUS ^Oliva^ - -The genus /Oliva/ is one of the favorites among collectors. It -comprises smooth, highly polished, porcelanous, and oval shells -with a deeply notched, long, narrow aperture. The columellar lip is -usually heavily calloused and ornamented with oblique folds. The -animal's foot is very large, and extends laterally into lobes which -curve back over the shell. In front the propodium is very large, -forming, as in /Natica/ and /Polynices/, a sort of plow. The mantle -lobes almost cover the shell when extended. - - ^O. literata.^ The only American example out of some sixty known - species. It is found in great abundance in sandy tide-pools along - the west Florida shores. It ranges from Hatteras to the West - Indies, and may be looked for in stations similar to those of the - naticas. It is exceedingly active, crawling rapidly over the sand - or burying itself very quickly out of sight, and is carnivorous. - The shell is highly polished, about two inches long, and pale - yellowish-white in color, covered with longitudinal, angulated, - or zigzag lines of chestnut. The spire is short, the sutures - channeled, and the columella calloused with white enamel, and - obliquely striated. (Plate LXXVII.) - - -GENUS ^Olivella^ - -The genus /Olivella/ resembles /Oliva/ very closely in conchological -characters, but the shells are, with few exceptions, exceedingly -small, and usually have a somewhat more elongated spire than is the -case in the genus /Oliva/ proper. The animal of /Olivella/ seems to -be a degenerate, for it possesses neither tentacles nor eyes. In -habit and station it resembles /Oliva/. - - ^O. mutica.^ In Floridian waters this species is exceedingly - common. It is not more than one fifth of an inch long, is highly - polished and shining, and yellowish-white in color, with revolving - pale rufous bands. It has the typical oliva-shape. - - [Illustration: PLATE LXXVII. 1, Marginella apicina, enlarged. - 3, Olivella biplicata, enlarged. 2, Oliva literata. 4, Conus - floridanus. 5, Cancellaria reticulata.] - - ^O. biplicata.^ A Californian species of considerable interest, the - largest of the olivellas. It was evidently used by the aborigines - as wampum or as ornaments, for a great many specimens are found - among buried Indian relics. This species is about the size and - shape of an olive. The spire is short, though longer than the - typical /Oliva/ spire, the shell is smooth and highly polished, and - the columella is thickly calloused, and has two entering folds near - the base. The color is creamy-white to dove-color, with a purple - sheen over all, and purple markings [pg401] about the base. - Professor Keep speaks of the vast numbers of these olivellas on - sandy stations along the Pacific coast. Having found a place where - a "little stream of water was oozing out from the bank of sand," - he proceeded to dig with a hoe. "I found them [/O. biplicata/] by - the hundreds," he continues, "and I had gathered about a thousand - before the tide came in. They seemed to lie in groups just under - the surface of the sand, yet wholly concealed from sight." (Plate - LXXVII.) - - ^O. boetica.^ A much smaller Pacific form, with a higher tapering - spire. It is brown to bluish in color, and often has yellowish - stripes. It is polished and shining. Found in sandy stations. - - -FAMILY ~CONIDAE~ - - -GENUS ^Conus^ - -This is a comprehensive family of several highly diversified genera. -Its most prominent genus is /Conus/, a name which indicates the -principal feature of the shell, for it is almost an exact cone in -shape. /Conus/, along with /Voluta/ and /Cypraea/, is entitled to the -honor of being considered an aristocrat among mollusks. There are -about three hundred and fifty species known, mostly tropical and -Indo-Pacific in distribution. The shells have many points of beauty -and are often of very high coloration and eccentric markings. Some of -the rarer forms are famous in conchological annals for the enormous -prices which they have commanded. The rare and beautiful /Conus -gloria-maris/ once brought L43 ($215) at an auction sale in London. -In all shells of /Conus/ there is a notch at the upper edge of the -aperture for the accommodation of a posterior canal. In some other -genera of this family this notch becomes a more prominent feature. -The animal has a well-developed foot, a retractile proboscis, eyes -situated upon the tentacles, and a fairly long siphon. Upon the -under surface of the foot is a conspicuous pore, which opens into a -water-vascular system of the foot. /Conus/ is accused of having a -poison-gland connected with the radula and of having shown vicious -traits when captured. The animals are shy, and remain most of the -time in hiding, while their pretty shells during life are generally -rendered obscure by a dull, colorless epidermis. There are but few -species of /Conus/ upon the Atlantic shores of the United States, and -these are confined to the warmer waters of Florida and the Gulf of -Mexico. [pg402] - - ^C. floridanus.^ A not unusual shell in shallow-water stations - throughout the Florida coast. It has almost the exact outlines of - a cone. The flattened shoulder is marked off by an acute carina; - the spire is low, but many-whorled and pagoda-like; the aperture is - long and narrow, and the lip is simple. The coloring is yellowish, - banded on a creamy-white background, or dotted in circular rows. - Length two inches. (Plate LXXVII.) - - ^C. pealii.^ One of the smallest species of this genus, its length - never exceeding one half of an inch, whereas the majority of the - cones are over two inches in length, and many of them rank as large - shells. This little Floridian species is regularly cone-shaped, - with carinated whorls, thin outer lip, and pagoda-like, low spire. - The color is reddish-brown with sky-blue spots, or bluish-brown - with lighter spots. There are encircling grooves about the base of - the shell. - - -FAMILY ~CANCELLARIIDAE~ - - -GENUS ^Cancellaria^ - -The last family of the /Gasteropoda/ to be considered is the -/Cancellariidae/, which has but one genus, ^Cancellaria^. There are -several species upon the east coast belonging to deeper-water zones, -but one well-known species, ^C. reticulata^, is very common on shore -stations from Hatteras south. The shell is oblong and solid, with a -moderate spire, and whorls slightly flattened below the sutures, and -is very roughly granulated or reticulated. The aperture is narrowly -ovate, and is ribbed inside. The columella has two very strong and -prominent plaits. The color is white, banded and variegated with -reddish-brown. Length an inch or more. (Plate LXXVII.) - - - - -CLASS =SCAPHOPODA= - - -FAMILY ~DENTALIDAE~ - -[Illustration: /Entalis striolata./] - -In nearly all collections of shells from the northeast coast of the -United States are certain specimens about one to one and a half -inches long, pure white, and shaped very much like an elephant's -tusk. They are round, hollow tubes, slightly curved, of larger -diameter at one end than at the other, and with an opening at either -end. There are two very common species of these tooth shells upon -the New England coast, [pg403] ^Dentalium dentale^ and ^Entalis -striolata^. The first has a simple round hole at the smaller end of -the shell, and is faintly marked by longitudinal striae; the other is -a smooth shell which has a notch-like fissure on the margin of the -apical perforation. Neither of these species is, strictly speaking, a -littoral form, for all the /Dentalidae/ range into deep water, many of -them living only in the profounder depths of the ocean. But these two -species are exceedingly common in the New England coastal waters, at -very moderate depths, and may sometimes be found upon the beach cast -up by storms. They live buried in the mud, and feed upon infusorians -and all manner of microscopic organisms. - -Upon the west coast ^Dentalium pretiosum^ is very abundant north of -California. It is almost like the east-coast /Dentalium/, but is more -slender. The Indians used to gather these shells and string them -together upon long threads to be carried about and used as money. -In California occurs ^Dentalium hexagonum^, a very delicate little -species with a slightly angulated shell. - -[Illustration: /Dentalium/, as seen in longitudinal section (except -the foot): /S/, shell; /Mt/, mantle; /Sm/, shell muscle; /Mh/, -mantle-cavity; /F/, foot; /Mk/, cephalic prominence or oral cone; -/T/, captacula; /R/, radula; /D/, intestine; /L/, liver; /Af/, anus; -/G/, cerebral ganglion; /N/, kidney; /Ge/, generative gland.] - -The animal of the /Dentalidae/ is remarkable, and easily merits the -rank of a separate molluscan class. It has no head, no tentacles, -no eyes, no heart, and no gills. It is a mollusk because it has a -mantle, a foot, and a radula. Its position, therefore, is between the -/Gasteropoda/, which it resembles in its univalve shell and radula, -and the /Pelecypoda/, to which it is related by the pointed foot and -the absence of head and tentacles, and also by the symmetry which -pervades its organization. - -Upon either side of the mouth, just beneath the flap of the mantle, -are bunches of ciliated, contractile filaments (/captacula/), -flattened at the end, which are supposed to be breathing-organs, and -are perhaps exserted for the purpose of catching food. [pg404] - -The entire absence of such important organs as the heart and gills, -together with the fact that they are undoubted mollusks, would -indicate that the /Scaphopoda/ are very degenerate animals. The -circulatory and respiratory system of mollusks is typically of a high -order. - -A great many specimens of the /Dentalidae/ dredged in New England -waters are dead shells, occupied by a worm which seals up the larger -opening, leaving only a small aperture through which it protrudes its -long white body. These must not mislead the collector into a vain -search for a mantle and other molluscan characteristics of anatomy. - -Some of the larger species of /Dentalium/ from deep-sea stations are -four to five inches in length. [pg405] - - -TABLE OF THE COMMONER NORTH AMERICAN PELECYPODS DESCRIBED IN THIS -CHAPTER - - Class =PELECYPODA= - - Order =PROTOBRANCHIATA= - - Families Genera Species - - - NUCULIDAE ^Nucula^ ^N. proxima^ - ^Leda^ ^L. tenuisulcata^ - ^Yoldia^ ^Y. limatula^ - ^Y. thraciaeformis^ - ^Y. sapotilla^ - SOLENOMYIDAE ^Solenomya^ ^S. velum^ - ^S. borealis^ - - Order =FILIBRANCHIATA= - - ANOMIIDAE ^Anomia^ ^A. simplex^ - ^A. aculeata^ - ^A. lampe^ - ^Placunanomia^ ^P. macrochisma^ - - ARCIDAE ^Arca^ ^A. ponderosa^ - ^A. noae^ - ^A. pexata^ - - MYTILIDAE ^Mytilus^ ^M. edulis^ - ^M. hamatus^ - ^M. californicus^ - ^Modiola^ ^M. modiolus^ - ^M. plicatula^ - ^M. tulipa^ - ^M. recta^ - - Order =PSEUDOLAMELLIBRANCHIATA= - - AVICULIDAE ^Avicula^ ^A. atlantica^ - ^Pinna^ ^P. muricata^ - ^P. seminuda^ - ^Perna^ ^P. ephippium^ - - OSTREIDAE ^Ostrea^ ^O. virginica^ - ^O. frons^ - ^O. lurida^ - - PECTINIDAE ^Pecten^ ^P. magellanicus^ - ^P. irradians^ - ^P. dislocatus^ - ^P. islandicus^ - ^P. aequisulcatus^ - ^P. hastatus^ - - Order =EULAMELLIBRANCHIATA= - - CARDITIDAE ^Cardita^ ^C. borealis^ - ^C. floridana^ - - ASTARTIDAE ^Astarte^ ^A. castanea^ - ^A. undata^ - - CYPRINIDAE ^Arctica^ ^A. islandica^ - - LUCINIDAE ^Lucina^ ^L. tigrina^ - ^L. floridana^ - ^L. pennsylvanica^ - ^L. dentata^ - ^L. californica^ - ^L. nuttallii^ - ^Loripes^ ^L. edentula^ - - TELLINIDAE ^Tellina^ ^T. radiata^ - ^T. alternata^ - ^T. bodegensis^ - ^T. tenera^ - ^Macoma^ ^M. secta^ - ^M. nasuta^ - ^M. baltica^ - ^M. proxima^ - ^M. tenta^ - - DONACIDAE ^Donax^ ^D. variabilis^ - ^D. californicus^ - - MACTRIDAE ^Mactra^ ^M. solidissima^ - ^M. similis^ - ^M. ovalis^ - ^M. lateralis^ - ^R[oe]ta^ ^R. canaliculata^ - - VENERIDAE ^Venus^ ^V. mercenaria^ - Var. ^mortoni^ - ^V. cancellata^ - ^Cytherea^ ^C. (Callista) gigantea^ - ^C. (Callista) maculata^ - ^Dosinia^ ^D. discus^ - ^D. elegans^ - ^Tivela^ ^T. crassatelloides^ - ^Tapes^ ^T. staminea^ - ^T. laciniata^ - ^Chione^ ^C. succincta^ - ^C. fluctifraga^ - ^C. simillima^ - ^Saxidomus^ ^S. nuttallii^ - - PETRICOLIDAE ^Petricola^ ^P. pholadiformis^ - ^P. carditoides^ - - CARDIIDAE ^Cardium^ ^C. magnum^ - ^C. isocardia^ - ^C. laevigatum^ - ^C. serratum^ - ^C. mortoni^ - ^C. substriatum^ - ^C. corbis^ - ^C. quadrigenarium^ - ^C. elatum^ - ^C. islandicum^ - ^C. pinnulatum^ - - MYIDAE ^Mya^ ^M. arenaria^ - - SOLENIDAE ^Ensis^ ^E. directus^ - ^Solen^ ^S. viridis^ - ^S. sicarius^ - ^S. rosaceus^ - ^Tagelus^ ^T. gibbus^ - - GLYCIMERIDAE ^Glycimeris^ ^G. generosa^ - - PHOLADIDAE ^Pholas^ ^P. costata^ - ^P. truncata^ - ^P. californica^ - ^Zirph[oe]a^ ^Z. crispata^ - - TEREDINIDAE ^Teredo^ ^T. navalis^ - - PANDORIDAE ^Pandora^ ^P. trilineata^ - -[pg408] - -[Illustration: Anatomy of a pelecypod, /Anodonta cygnea/. The animal -with most of the left mantle lobe removed. /a/, excretory opening; -/a. ad./, anterior adductor muscle; /a. r./, anterior retractor -muscle; /au./, left auricle; /d. p. a./, dorsal pallial aperture; -/ex. sph./, exhalant siphon; /ft./, foot; /in. sph./, inhalant -siphon; /kd./, kidney; /l. ext. gl./, left external gill; /l. ext. -plp./, left external labial palp; /l. int. gl./, left internal gill; -/l. int. plp./, left internal labial palp; /l. m./, cut edge of left -mantle lobe; /mth./, mouth; /p. ad./, posterior adductor muscle; -/pc./, pericardium; /p. r./, posterior retractor muscle; /prc./, -protractor muscle; /rct./, rectum; /r. m./, right mantle lobe; /v/, -ventricle; /v. m./, visceral mass.] - -[Illustration: Anatomy of a pelecypod, /Anodonta cygnea/. -Dissection from the left side. /a/, excretory opening; /a. ad./, -anterior adductor muscle; /a. ao./, anterior aorta; /a. v. ap./, -auriculo-ventricular aperture; /bl./, urinary bladder; /c. pl. gn./, -cerebropleural ganglion; /d. d./, duct of digestive gland; /d. -gl./, digestive gland; /d. p. a./, dorsal pallial aperture; /ex. -sph./, exhalant siphon; /ft./, foot; /g. ap./, genital aperture; -/gon./, gonad; /gul./, gullet; /i. l. j./, interlamellar junction; -/in. sph./, inhalant siphon; /int./, intestine; /kd./, kidney; /m/, -mantle; /mth./, mouth; /p. ao./, posterior aorta; /p. ad./, posterior -adductor muscle; /pc./, pericardium; /pd. gn./, pedal ganglion; /r. -ap./, renal aperture; /r. au./, right auricle; /rct./, rectum; /r. p. -a./, reno-pericardial aperture; /st./, stomach; /ty./, typhlosole; -/v./, ventricle; /v. gn./, visceral ganglion; /w. t./, water-tubes.] - -[pg409] - - - - -CLASS =PELECYPODA= - - -This is a large and important class of the /Mollusca/, comprising an -extensive group of animals, which vary widely in structure. Next to -the /Gasteropoda/, it is the largest class of the phylum in number -of genera and species. The name indicates a "hatchet-shaped" foot, -but in many cases it is a misnomer. /Acephala/, meaning "without a -head," is also employed for this class, and is, perhaps, a better -term. /Lamellibranchiata/, referring to the type of gills prevalent -throughout the division, is another name often used. The popular -name "bivalves" is an altogether correct one, for all the animals -of this class have two shells. To the /Pelecypoda/ belong the -oysters, clams, scallops, mussels, and, in short, all the /bivalve/ -mollusks (the word "valve" meaning "shell"). The organization of a -pelecypod is entirely similar to that of a gasteropod or a chiton -in its fundamental or essential plan, but it differs widely from -both in matters of detail. If the student will keep in mind the -general principles of gasteropod or the amphineuran structure when -he dissects his first pelecypod, he will quickly see that the latter -is about the same as a chiton would be were it folded over from a -longitudinal median line as axis along its back, so that the opposite -mantle-edges would meet, and its various shell-plates would unite -upon either side into a single valve; or it is very like a gasteropod -made symmetrical, and covered upon its two sides by separate shells -instead of covered over its top by one shell. The loss of head, -eyes, and tentacles, the substitution of labial palps, the extension -and greater development of the gills, the modification of the foot -and mantle, and the presence of certain special glands in the -/Pelecypoda/ become mere matters of anatomical detail. [pg410] - -Any large clam will serve for dissection. In the neighborhood of -New York the edible species known as the "Little Neck" clam (/Venus -mercenaria/), or the larger /Mactra/ of the sandy shores, will -answer the purpose very well. In Florida, /Callista/, /Venus/, and -/Cardium/ are all available. On the west coast the large, heavy -/Tivela crassatelloides/ is probably the best subject. The oyster -(/Ostrea/) is a degenerate type; and the scallops (/Pecten/) and the -mussels (/Mytilus/ and /Modiola/) have certain special modifications -of their organs which might prove confusing, so these genera are not -recommended for dissection and study at first. - -Boiling is apt to shrivel and distort the soft, fleshy animal of -the bivalves, and it is far better to examine a fresh specimen. The -surest way of opening a clam without injuring the animal is to break -one of the shells by sharp taps of a hammer, using great care not -to lacerate the body within by a too vigorous assault. Pick off the -broken pieces after having separated them carefully with a knife from -the mantle margin, to which they cling, and after having cut through -the tough adductor muscles as close to the shell as possible. The -subject for anatomical study is then prepared "upon the half-shell." - - -THE MANTLE - -The mantle is generally very thin, often a fleshy film of the finest -tissue, and adheres to the inner side of each valve. The outer rim -of the mantle is thickened and free, i.e., is not attached to the -shell. This free portion is capable of slight extension beyond the -margin of the shell when the valves are opened and the animal is off -guard. In many genera the mantle edge is highly ornate, being waved, -crenulated, or fluted, or is beset with several rows of papillae, and -is often richly colored. Mr. Hickson, a naturalist, who traveled in -Celebes, says that the brilliant coloring of the mantle margins of -mollusks contributed largely to the extraordinary color-effects upon -the coral reefs. - -It will be seen that the mantle entirely incloses the animal at the -back and sides, just as the cover of a book incloses the pages or -printed portion. At the posterior end of the animal there is usually -a point--or perhaps two points--at which the flaps of [pg411] the -mantle lobes unite in order to form two openings. These openings are -called the siphons. - -[Illustration: 1, /Solecurtus strigillatus/, showing partly united -siphons covered with leathery integument: /s. af./, incurrent siphon; -/s. ef./, excurrent siphon; /SS/, the two uniting. 2, /Cardium -edule/, showing partly united siphons with papillaceous orifices: -/A/, excurrent; /B/, incurrent siphon; /F/, foot. 3, /Scrobicularia -piperata/, in its natural position in the sand, showing very long -tubular siphons: /A/, excurrent siphon; /B/, incurrent siphon.] - - -SIPHONS - -In some cases the mantle lobes do not actually unite to form regular -siphonal openings, but in life the free mantle-edges have a way -of adjusting themselves posteriorly to form /functional siphons/ -without actually coalescing. Usually, however, the mantle flaps -not only unite posteriorly to form true siphons, but are capable -at that point of varying degrees of protrusion from the shell, and -when extended the siphons appear as two tubes. In some genera these -siphonal tubes are very long; in others they are fastened together -and surrounded by a tough, leathery integument, [pg412] which, like -the siphons proper, is only an extended portion of the mantle-edge. -The orifices of the siphons are generally papillaceous. These two -siphons (for there are always two if there are any at all) are the -/anal/ or excurrent (upper) and the /branchial/ or incurrent siphon. -The function of the latter is to draw in the pure water to bathe the -gills and to furnish food, while the office of the former is to eject -waste materials and the water which has already passed over the gills. - -[Illustration: Diagram illustrating the various degrees of union of -the mantle lobes: A, mantle completely open; B, rudiments of siphons, -mantle still completely open; C, mantle closed at one point; D, -mantle closed at two points, with complete formation of siphonal -apertures; E, development of siphons, ventral closure more extended; -F, mantle closed at three points, with fourth orifice; /f/, foot; /s. -a./, /s. b./, anal and branchial siphons; 1, 2, 3, first, second, and -third points of closure of mantle; /b. o./, byssal aperture.] - - -MANTLE FUSION - -Besides the points of juncture where the mantle-edges unite to form -the siphons, the coalescence of the two mantle lobes may be extended, -and they may become further united and fused together at other -points. Indeed, the fusion of the mantle-edges may become almost -complete; but it always leaves the siphonal openings and a third -opening through which the foot may be extended. This opening for -the foot is called the /pedal opening/, or orifice. In such cases, -therefore, the mantle becomes much like a bag or sac. The degree of -fusion of the mantle-edges appears to correspond closely with certain -changes in the organization of the animal, and this feature must be -regarded as a very important character. [pg413] - -The figures on pages 411, 412, and 413 show the degrees of mantle -fusion in various groups from the open to the almost wholly closed -types. One (A, page 413) gives an example of very large siphons -united together and protected by the tough, leathery integument. To -the right of this cut may be seen the foot projecting from the pedal -opening in the mantle. Another gives the two siphons of /Cardium/, -the lower or branchial one being the longer. The mantle-edges below -are fluted, and a large foot projects forward. Another shows two -siphons of /Scrobicularia/, of the free and greatly extended type. -Fig. B (page 413) illustrates the ventral portion of a pelecypod, -which shows very well the most advanced type of mantle fusion. -Besides the siphonal openings at the end of the long projection to -the left, the only other opening is the very small orifice marked -"2," for the accommodation of a small, insignificant foot. In the -other figures different degrees of mantle fusion are indicated. - - -[Illustration: A: 1, incurrent siphon; 2, excurrent siphon; 3, foot. -B: 1, siphons; 2, pedal opening.] - -Before removing the mantle from one side of the specimen to be -examined, note the two strong muscles which are at either end of the -body. These are the /anterior/ and /posterior adductor/ muscles, -their office being to hold the valves tightly shut. They are of great -strength, as any one may prove to his satisfaction by attempting -to open a clam. Through a long series of forms these two muscles -approach each other in position, and in the scallops and the oysters -there is but one adductor muscle, occupying a central position. -Morphologically it is the survival of the posterior adductor. - - -THE BRANCHIAE OR GILLS - -Removing carefully the thin, fleshy mantle, the gills are exposed -to view--that is, of course, the gills of that side of the [pg414] -animal, for there are two sets, one upon each side of the body, or -visceral mass, and lying between the body proper and the mantle -folds. Each set consists of two plate-like bodies with a texture of -reticulated or basketwork appearance. Thus there are the inner and -outer right gills and the inner and outer left gills. If one gill is -removed and carefully examined it will itself probably be found to -be double, consisting of many filaments placed side by side and then -doubled back like a row of hairpins, the filaments being united by -interciliary processes, or by vascular channels together with more or -less dense connective tissue. - -The modifications of the pelecypod gills are difficult to follow, -but the principle upon which they perform their duties is the same -in all cases. The gill-filaments are all connected with a long vein, -and, being hollow, admit the blood, which is aerated by close contact -with the water and is then returned to another vein in immediate -connection with the auricles of the heart. There is another function -accomplished by the gills, which in some families seems to be quite -as important as their respiratory one, namely, the office of giving -lodgment to the ova while in process of development before hatching. -At certain seasons the gills of a number of pelecypod genera become -literally filled with eggs; sometimes this curious phenomenon extends -to the mantle itself, and more or less to the entire surface of the -animal. The eggs are first regularly ejected from the genital ducts -and find lodgment upon the body-surface, but usually only upon the -gills, where they remain as in a brood-pouch between the lamellae of -the inner and outer gills. When the eggs hatch, the free-swimming -young escape from the mantle cavity. Probably not more than one -individual in a million ever reaches maturity. - -The figure on page 408 shows the mantle removed, exhibiting the -gills, the foot, the labial palps, and the pericardium, inside of -which is the heart. Removing the gills, we find exposed the body, or -visceral mass, which, as in the /Gasteropoda/, is thickened below -into the foot. A longitudinal section is shown on page 408, the -visceral mass being sliced almost through the middle; a portion of -the gills of the farther side shows below. [pg415] - - -THE FOOT - -The foot undergoes great variation, from a strong, powerful organ -capable of forcing its way through heavy gravelly bottom or burrowing -deeply into the sand or mud, to the merest trace of a pedal organ. -In the oyster the foot has become almost entirely atrophied; the -stationary life led by the animal renders such an organ quite -unnecessary. Excepting in a few families, the pelecypod foot is -well developed. In a number of genera the foot contains a gland -for the secretion of long silk-like or horn-like fibers, which -are collectively called a /byssus/. The use of a byssus is for -attachment to any object to effect a temporary or permanent lodgment. -The accompanying cut shows /Mytilus edulis/, a common east-coast -pelecypod, attached by its byssus to a piece of wood. Most bivalves -having a strong byssus exhibit a feeble development of the foot; -nearly all bivalves, however, show traces, sometimes only in the -embryo, of a byssal gland. - -[Illustration: /Mytilus edulis/, attached by its byssus (/By/) to a -piece of wood: /F/, foot; /S/, excurrent siphon, the branchial siphon -being below it and not closed.] - -[Illustration: /Pecten opercularis/, showing the ocelli, or eyes, on -the two edges of the mantle.] - -The visceral mass contains the liver, the exceedingly large -generative glands, the kidneys, etc., and through all this soft -whitish or reddish mass the alimentary canal wanders about in a -tortuous fashion, finally passing through the pericardium and the -ventricle of the heart, and terminating just over and back of the -posterior adductor muscle. [pg416] - -The pelecypods have no head or tentacles, but the place of the latter -is taken by two pairs of triangular flaps upon either side of the -mouth. These are called the /labial palps/, and they no doubt operate -by means of their ciliated surface to keep in motion the current of -water over the gills and to the mouth. - -As a rule, pelecypods have no eyes, but when eyes are present they -are situated upon the edge of the mantle. The eyes are not highly -developed organs, but they nevertheless appear to be very sensitive -to light, for the bivalves which are so endowed will, when kept in -aquaria, instantly close their shells when the shadow of a fish -passes over them. - -The heart lies in the pericardium and is situated dorsally, just in -front of the posterior adductor muscle. It has a median ventricle -and two lateral auricles, each connected with the branchiae upon -its respective side. It seems a curious economy that passes the -intestine through the ventricle, but this is the case in the great -majority of pelecypod genera. The vascular system is closed and -is of a high order. It is probable that "breathing" takes place -upon the inner mantle surfaces as well as in the gills themselves; -for these surfaces are crowded with excessively fine and delicate -capillaries, which bring the blood very near to the water. This power -of "breathing by the skin" is quite characteristic of the /Mollusca/ -in general. - -Having once familiarized one's self with the more prominent features -of pelecypod organization, it becomes very interesting to examine -anatomically every new form that is captured. Surprises are always in -store, and sometimes the peculiar juxtaposition and relative sizes of -the organs are a trifle confusing; but, upon the whole, the bivalve -organization is simple and lends itself far more readily than does -that of the gasteropods to satisfactory examination. Some of the more -striking anatomical peculiarities are reserved for mention in the -notes upon the various genera and species common upon our shores. - - -THE PELECYPOD SHELL - -As has been seen, the testaceous covering of the /Pelecypoda/ -consists of two valves or shells which fit more or less closely -and [pg417] firmly together and are placed one upon either side of -the animal. The two valves are always held together tightly along a -dorsal margin by a "hinge ligament," an exceedingly tough, leathery -substance, and they are usually secured the more firmly by a system -of interlocking teeth, which project from the hinge. The opening and -shutting of the valves is controlled by the adductor muscles of the -animal, by the /ligament/ which binds the valves together, and by -the /cartilage/, an elastic pad of rubber-like appearance which is -lodged just within the hinge, and is compressed when the valves are -closed together. Thus, when the valves are closed, there is always a -strain upon the adductor to overcome the elastic resistance of the -cartilage. When a pelecypod dies and the pull of the adductor muscles -is released, the valves gape open. - -[Illustration: The interior characteristics of a pelecypod shell. -Left valve of /Venus gnidia/: /A/, anterior, /B/, posterior, /C/, -dorsal, /D/, ventral margin; /AB/, length, /CD/, breadth of shell; -/a. m./, anterior, /p. m./, posterior impressions of adductor muscle; -/p/, pallial line; /p. s./, pallial sinus; /l/, ligament; /lu./, -lunule; /u/, umbo; /c/, cardinal teeth; /a. l./, anterior lateral -tooth; /p. l./, posterior lateral tooth.] - -The summit or apex of the valve is called the /umbo/, or /beak/. It -is usually twisted to some extent, and in certain forms develops a -suggestive spiral figure. The beaks of the valves are the points -where the shell-growth begins, the secretion of calcareous matter -being made by the mantle margin and deposited about the edges of the -valves; the growth is therefore constantly away from the umbones. - -The umbones usually point forward. In many species they touch each -other over the hinge-margin or approximate very closely; in other -species the hinge-margin is very wide and the beaks are comparatively -far apart. The hinge-margin, lying adjacent to the umbones, is known -as the /dorsal margin/ of the shell, in contradistinction to the -/ventral margin/, opposite the umbones. The /anterior margin/ is the -front edge and the /posterior margin/ the hinder edge of the shells, -through which the siphons may project. - -When the umbones are about central in respect to the posterior -[pg418] and anterior margins, the shells are said to be -/equilateral/. When the two valves are almost exactly alike in size -and shape they are called /equivalve/. - -In many forms there is a heart-shaped space upon the dorsal margin -of the closed valves forward of the umbones, called the /lunule/. -Similarly placed back of the umbones is sometimes a more or less -clearly defined space called the /escutcheon/. The outer surface -of bivalve shells admits of infinite variety of sculpturing and -ornamentation, ranging from a perfectly smooth to a heavily ribbed, -nodose, spinous, or deeply decussated surface. The color-markings are -often brilliant and eccentric. - -The right and left valves may be distinguished by remembering that -the siphons are always posterior, and that the umbones usually point -forward. - -The hinge of bivalve shells undergoes many variations in the -different genera. The simplest type is a smooth edentate surface -where the two valves meet and are held together only by the strong -ligament. Generally, however, there is a system of interlocking -teeth, those in the center of the hinge being the /cardinals/ and -those upon either side the /laterals/. In some forms there are rows -of fine comb-like teeth along the hinge-margin, with no distinction -between cardinals and laterals. - -The object of these hinge-teeth is at once obvious, for they give a -rigidity and increased strength to the entire mechanism, especially -when closed. There is occasionally a saucer-shaped plate or platform -just under the cardinal teeth and within the shell, called the -/fossette/. Upon this rests the internal elastic cartilage. - -Upon the smooth interior surfaces of the valves are always certain -markings, which correspond to anatomical features of the animal and -are consequently of considerable importance in the determination -of the systematic position of the specimen. First, the well-marked -impressions left by the adductor muscles will be noted; then a more -or less distinct line which, describing roughly a circle, connects -the two muscle scars. This line represents the points at which the -mantle became detached from the shell. In other words, all the space -within this /pallial line/ (barring the [pg419] muscle scars) was, -in life, covered by the mantle, which adhered tightly to it. The -space between this pallial line and the outer edge of the valve was -occupied in life by the free portion of the mantle. Frequently a -depression in the pallial line toward the center of the valve is -seen in the posterior end. This is called the /pallial sinus/, and -marks the space occupied by the siphons. The pallial sinus is absent, -moderate, or deep, according as the animal possessed no siphons, or -small or large ones. - -The length of bivalve shells is measured from their anterior to their -posterior ends, while the height indicates the greatest diameter -between the umbones and the ventral margin. - -The greatest possible degree of variation exists in the structure of -the pelecypod shell. Every degree of thickness from the most fragile, -tissue-like structure to the very heavy and ponderous tests of some -of the /Veneridae/ is to be found. There is also a range in size -from the very minute /Spheria/ to the giant /Tridacna/ of Eastern -seas, which weighs several hundred pounds. As in the /Gasteropoda/, -there is fortunately a very close parallelism between shell and -anatomical variations. One very quickly learns to place a bivalve in -its systematic position by a mere glance at the shell alone. While -the higher classification into orders, suborders, etc., is based upon -anatomical features, the genera often and the species always are -founded upon conchological or shell characters. - -The /Pelecypoda/ offer one of the most interesting fields for -investigation and study among the invertebrates. Although by no means -neglected, they have not received as much attention on the part of -biologists as has been given to other phyla, or indeed to the other -classes of this same phylum. - - -CLASSIFICATION OF THE PELECYPODA - -Nearly every systematic writer upon the mollusks has attempted to -give a good classification of the bivalves, yet none of the results -is wholly satisfactory. The scheme now generally adopted is one based -upon modifications of the gills, or branchiae, and has practically -replaced all the older classifications, which depended [pg420] upon -the presence or absence of siphons, the degree of mantle fusion, -the arrangement of teeth upon the hinge, the number of adductor -muscles, etc. The idea of arrangement according to gill-structure is -substantially this: the development of the gill from the simplest -and most rudimentary type through successive stages to a higher, -more complex, and presumably more efficient type, marks the natural -progress or development of the pelecypod animal itself. By adopting -the gill as a guide one follows, therefore, a natural method. Upon -the other hand, the presence or absence of siphons, the shape -of the foot, the number of adductor muscles, all depend merely -upon the acquired habits of the animal, these particular features -being subject to modification according to environment and changed -conditions. - -The five orders of the /Pelecypoda/ are: /Protobranchiata/, -/Filibranchiata/, /Pseudolamellibranchiata/, /Eulamellibranchiata/, -/Septibranchiata/. - -[Illustration: Structure of the branchiae or gills of pelecypods, -seen diagrammatically in section: A, /Protobranchiata/; B, -/Filibranchiata/; C, /Eulamellibranchiata/; D, /Septibranchiata/; -/e/, /e/, external row of filaments; /i/, /i/, internal row of -filaments; /e'/, external row or plate folded back; /i'/, internal -row folded back; /f/, foot; /m/, mantle; /s/, septum; /v/, visceral -mass.] - -The first includes the simpler type of gill as represented in the -accompanying figure (A). Its filaments are short and not reflected. -The second, represented in Fig. B, has the filaments long, reflected, -and connected (each filament to its adjacent ones) by means of -surface cilia. The third type of gill resembles the last except that -the ends of the filaments of the outer gill are attached to the -mantle, and the ends of the filaments of the inner gill are attached -to the foot or visceral mass. The fourth type of gill is far more -highly [pg421] developed. The adjacent filaments are connected, not -by cilia, but by vascular channels, and the depending and recurved -portions of each filament are also connected in a manner presumed to -admit of the passage of blood. This gives to the organ the appearance -of basketwork or network. The ends of the filaments are attached to -the mantle and to the visceral mass, as in the last order, forming -cavities or chambers above (see Fig. C). This order includes the -great majority of the /Pelecypoda/. - -The fifth and last order is confined to but two rather obscure -families, in which the gill-development is carried to the point of -substitution of muscular partitions which form a separate chamber -connected with the mantle cavity by a narrow slit, the surface of the -chamber having respiratory functions (Fig. D). - -The collector of living marine objects who has become fascinated by -their beauty and who derives pleasure from examining the greater -beauty of their structures will find a rich field for research in -the pelecypod gills. But unless he has time at his disposal and some -skill with a microscope, he would do well not to venture too far into -this alluring but difficult and vexatious subject. - -Our coastal waters are fairly rich in bivalves, but the most -strikingly handsome species of this class--and there are many of -them--are inhabitants of warmer seas. Of the great number of bivalves -to be found upon our own shores we can only mention briefly some of -the commonest species. - - -ORDER =PROTOBRANCHIATA= - - -FAMILY ~NUCULIDAE~ - -In this family the gills are of the simplest and most primitive type. -The mantle-edges are entirely open along the ventral margin, but they -are united posteriorly in some of the /Nuculidae/ to form two short -siphons. The palps are exceedingly large. The foot is also large, -and by its disk-like surface is adapted to creeping, much as is a -gasteropod foot; its edges are often crenulated or scalloped, and -there is no trace of a byssus. The shells are [pg422] equivalve, and -their most prominent feature is the hinge, which is beset with sharp, -comb-like teeth in two straight rows, one upon each side of a central -pit, a space reserved for the ligament. - - -GENUS ^Nucula^ - - ^N. proxima.^ The commonest of several species of the genus found - along the New England coast. It is oblique, with a light-olive - epidermis, nacreous interior, and finely crenulated margins. Its - length is about one quarter of an inch. The animal has no siphons. - It lives in either muddy or pebbly stations near the shore, and - probably exists in countless thousands in all the bays and harbors - of the New England coast. - -[Illustration: /Nucula proxima./] - - -GENUS ^Leda^ - - ^L. tenuisulcata.^ This species has a longer shell than the - preceding; it is more produced behind, and is narrowed into a - blunt, slightly gaping point. The epidermis is light greenish, and - the shell has a pearly luster within. The outer surface of the - shell is concentrically grooved; the beaks are smooth. The foot is - disk-shaped, and the animal is provided with small siphons. The - length of this shell is about one inch. Its station is the muddy - bottom in shoal water on the New England coast. - -[Illustration: /Leda tenuisulcata./] - - -GENUS ^Yoldia^ - - ^Y. limatula.^ This species has the same sort of toothed hinge - exhibited in the two preceding species, but the shell is - considerably larger (two inches), with a smooth greenish glazed - epidermis. The beaks are nearly central. The interior of the shell - is light bluish and pearly. The animal has two slender, short, - united siphons and a disk-shaped foot with simple margins. This - species can make excellent use of its foot, for it crawls with - rapidity, and also can execute leaps in an astonishing manner. - Found in muddy stations in shoal water on the New England coast. - - [Illustration: /Yoldia limatula./] - - ^Y. thraciaeformis.^ A much larger species, found on the New England - coast. It may be distinguished by a rib-like wave extending - obliquely from the umbones to the ventral margin of the shell. It - measures over [pg423] two and a half inches in length and one and - a half inches in height, and is dark olive-green. The foot is like - that of /Y. limatula/. The labial palps are exceedingly large. - - ^Y. sapotilla.^ The shell is ovate, prolonged on one side, thin, - fragile, translucent, and covered with a thin, glossy epidermis, - greenish in color. The anterior half is semi-oval, the posterior - portion narrowed and compressed; within it is pearly-white, with a - triangular cartilage cavity, and sixteen to eighteen pointed teeth - on each side. In length it is little less than an inch. Found from - Long Island Sound northward. - -[Illustration: /Yoldia thraciaeformis./] - -[Illustration: /Yoldia sapotilla./] - - -FAMILY ~SOLENOMYIDAE~ - - -GENUS ^Solenomya^ - -Two species of this genus, which are greatly prized by collectors -on account of the extraordinary development of the epidermis of the -shell, occur in New England waters. The strong corneous periostracum -of a deep chestnut-color projects considerably beyond the margins -of the valves; the shells are exceedingly thin and fragile, and are -marked with radiating lines. The two species are easily distinguished -by their difference in size. ^S. velum^ is about one inch long and -one half of an inch high. ^S. borealis^, of arctic range, is quite -twice that size. Their anatomy is similar in essentials to that of -/Yoldia/. These species live near shore in sandy bottoms, and are -occasionally found upon the beach between tides. Chelsea Beach, just -north of Boston, is an often-quoted locality. - -[Illustration: /Solenomya velum./] - - -ORDER =FILIBRANCHIATA= - -There are several families of this order which are well represented -in both the Atlantic and the Pacific waters of the United States. The -characteristic feature of this group of bivalves is the filamentous -gill, that is, a gill with the filaments long, doubled back, and -united to each other only by ciliary junctures. These [pg424] -junctures are so slight that they break readily when a specimen of a -gill is handled, leaving the filaments free. The presence of a byssal -gland in the foot, and often a well-developed byssus, is another -characteristic of this order. - - -FAMILY ~ANOMIIDAE~ - - -GENUS ^Anomia^ - -This is a family of peculiar and highly specialized forms. /Anomia/ -has an irregularly rounded shell, with one convex and one flat -or concave valve. There is no regular hinge or well-defined -hinge-margin, but a raised fossette, or cartilage plate, occupies a -position at the top of the valves. In the flat valve there is a large -oblong hole just under the apex, through which projects a calcified -byssus, by means of which the animal secures itself to oysters, dead -shells, stones, or any solid object. The anomias, which have become -stationary in habit, have practically lost their foot. The gills are -very large and curved, while all the organs seem to be abnormally -placed on account of the huge byssus and byssal muscle. For the -byssus to pass, as it does, through a specially prepared hole in one -of the valves is an extraordinary departure from the conventional -types of byssiferous species. The heart is not traversed by the -intestine. Altogether, then, /Anomia/ is a very curious genus. - -[Illustration: /Anomia simplex/, side view. /Anomia simplex/, from -below.] - - ^A. simplex.^ The commoner large form of New England. It varies - from one to three inches in diameter, is exceedingly irregular - in shape, and its surface is variously undulated and plaited in - accordance with the surface of the object to which it is attached. - Thousands of these valves, disjointed and separated, are cast upon - the beaches all along our Atlantic coast. They are light green to - salmon- or copper-color, generally fragile and scaly, and have a - peculiarly dulled (as though greased) nacre. [pg425] - - ^A. aculeata^ is much smaller than the last species, and the - surface of the convex valve is roughened by prickly scales. The - smaller valve is very thin, with an almost circular aperture for - the byssus. Its diameter is about half an inch. Found attached to - stones, etc., about the holdfasts of /Fucus/. - - [Illustration: /Anomia aculeata/, from above. /Anomia aculeata/, - from below.] - - ^A. lampe^, a California species ranging more to the south, is - small (half an inch), and greatly resembles the east-coast /A. - aculeata/, save as regards the smooth surface of the former. - - -GENUS ^Placunanomia^ - - ^P. macrochisma.^ This species occurs on the Californian coast. It - has the same sort of calcified byssus as /Anomia/, and also the - hole to accommodate it in the smaller valve. The scar formed by the - muscle which controls the byssus is curiously rayed in this genus. - The normal shape of the shell is circular; it is pearly within, and - of a greenish tinge without. Two to four inches in diameter. (Plate - LXXVIII.) - - -FAMILY ~ARCIDAE~ - - -GENUS ^Arca^ - -The /Arcidae/ may always be distinguished by the long row of comb-like -teeth upon the hinge, the total want of siphons (a fact which may be -discovered in the shell alone by its lack of a pallial sinus), and -the solid trapezoidal or round shell, with its tendency to strong -ribs radiating from the umbones. The periostracum, or epidermis, is -heavy and often velvety or even hairy. The animal of /Arca/ has the -gills placed in an oblique position; the foot is large and strongly -developed. No trace of mantle fusion exists. The mantle-edges bear a -row of composite eyes. The gill-filaments are entirely free, there -being even no ciliary junctions. - -[Illustration: /Arca pexata./] - - ^A. pexata.^ An exceedingly common species in Long Island Sound and - on the coast of New Jersey. The shell is oblong, with prominent - beaks directed forward. The hinge-teeth are arranged in a row - posterior to the beaks, while just under the beaks are a number of - irregular cartilage-pits. About thirty-two to thirty-six radiating - ribs ornament the shell. The inner margins of the shell are rather - deeply scalloped; the epidermis is thick, shaggy, and dark - [pg426] brown. Length two to two and a quarter inches; height two - inches. /A. pexata/ is one of the few pelecypods which have red - blood, a fact which accounts for its popular name of "bloody clam." - - ^A. ponderosa.^ The most prominent /Arca/ upon our Atlantic - coast, especially south of Virginia. The beaks of this shell are - very prominent, and do not approach each other very closely on - account of the wide dorsal margin of the shells, the large space - between the beaks being occupied by an external ligament. The - hinge-teeth are smaller in the middle. There are from twenty-five - to twenty-eight ribs; the ventral margin of the valves is somewhat - contracted in the middle. Length two and a half inches; height two - inches. Very heavy and solid. This exceedingly common species is - often cast upon the beaches south of Hatteras in numbers beyond - computation. In life it is covered with a heavy, coarse, velvety - epidermis, almost jet-black in color. (Plate LXXVIII.) - - ^A. noae.^ The well-known "Noah's-ark" shell, a common species - along the shores of the Southeastern States. It also occurs in - the Mediterranean. Unlike most arcas, it spins a byssus, by means - of which it attaches itself to the under surfaces of stones at - low water. The hinge-margin is perfectly straight and regularly - toothed. The beaks are high and are situated very far forward. The - dorsal margin of the valves is strikingly large, and is marked by - lattice-like grooves; it forms a concave surface over an inch in - width between the umbones. The shell is strongly ribbed without. - The ventral margin of the valves is sinuous and gapes slightly at a - central point for the accommodation of the byssus. (Plate LXXVIII.) - - -FAMILY ~MYTILIDAE~ - - -GENERA ^Mytilus^, ^Modiola^ - -[Illustration: PLATE LXXVIII. Placunanomia macrochisma. Arca -ponderosa. Arca noae. Mytilus hamatus.] - -The /Mytilidae/ are a large family, including the mussels, so -commonly found between tides upon all shores. The two ordinary -genera /Mytilus/ and /Modiola/, which often occur associated -together upon our eastern coast, may readily be distinguished one -from the other by the position of their beaks. In the former genus -the beak is terminal, that is, it is situated at the very tip-end -of the shell; in the latter genus it is not quite terminal. Aside -from this simple feature, the genera are practically the same, the -animals being identical. /Mytilus/ and /Modiola/, commonly known as -mussels, have acquired the stationary habit and are provided with a -relatively small foot (in some species amounting to no more than a -mere tubercle); but in place of a useful foot is a well-developed -byssogenous gland, which secretes an [pg427] exceedingly tough, -fibrous byssus. By means of this the animal may not only attach -itself firmly to any sort of object, but may actually move about. -Fibers of the byssus are thrown out, and, as though possessed of -life, they seize upon objects in the direction in which /Mytilus/ -desires to move, and by contraction of the muscles which control -the byssus the animal is drawn forward, the operation being then -repeated. It must be a very tedious method of travel. However, the -/Mytilidae/ are not restless creatures. They pass their lives content -to remain firmly fixed to some object, and their movements, if any, -are within a very narrow circle. The animal has very long gills -of the usual filamentous type. The mantle fuses at one point to -form an anal siphon, the lower or branchial one being, therefore, -functional. The palps are large. One curious feature of this group is -the enormous extent of the genital glands, which actually appear to -pervade the entire structure of the animal, gills, mantle, foot, and -all. At times the whole being is a veritable receptacle for myriads -of tiny yellowish eggs. - -[Illustration: /Mytilus edulis/, typical form.] - -The /Mytilidae/ are of universal distribution, and are for the most -part of littoral or shallow-water range. Some species are esteemed as -an article of food, notably /Mytilus edulis/. - -Mussel-culture has been profitably carried on in France for a long -time, but the genus has not been utilized to any extent as food in -this country. [pg428] - - ^Mytilus edulis^ is exceedingly abundant along the New England - coast. It lives in colonies, often between tides, in pebbly - stations among large rocks. It is always so fastened by its byssus - that the beaks of the valves point downward, and the ventral margin - projects above the sand or mud. The color of the epidermis in the - adult form is black or a deep blue-black; the shell proper is - violet. Hinge-teeth are wanting. Length two and a half inches. A - variety of this species, ^M. pellucidus^, is often found associated - with the typical form. It is brightly rayed in green and yellow. - /M. edulis/ occurs in Europe, where it is quite extensively used as - food. It also occurs (by importation) in San Francisco Bay. - -[Illustration: /Mytilus edulis/, rayed-color variety.] - - ^M. hamatus^ has a more southern range than has /M. edulis/, and - is found from the Chesapeake southward. Its shell is considerably - twisted just below the umbonal region, while its whole surface is - densely striated. Its color is dark fuscous. Length one to two - inches. It is found in great numbers attached to oysters by its - byssus. In Florida it is very common. (Plate LXXVIII.) - - ^M. californicus.^ A common west-coast species, which finds its - station among rocks exposed to the surf. It is about the same size - as /M. edulis/, but has a lighter brownish glossy epidermis and - several conspicuous, well-rounded, radiating ribs. The animal is - orange-colored. - -[Illustration: /Modiola modiolus./] - - ^Modiola modiolus.^ After violent storms upon the New England - coast, when a large /Laminaria/ is wrenched from its rocky bed - and washed ashore, its roots will, in many cases, be found - clinging to this large mussel. The thick glossy epidermis of deep - chestnut-color folds over the margin of the valves, and the outer - surface, especially near the ventral margin, is covered with a - tough hairy growth. Length four to five inches. The animal is - orange-red. The great size and swelling fullness of this species - at once distinguish it from all others upon our coast. It is not a - shallow-water form, but is extremely common upon all beaches north - of Hatteras. It also occurs in Alaskan waters to Puget Sound, where - it is known as the "great horse-mussel." Sometimes these large - modiolas may be found in rocky tide-pools which are washed by the - surf at high tide. They hide far back in the crevices of boulders, - and [pg429] are not easily detected. They are not uncommon in - such stations at Mount Desert, Maine. - -[Illustration: /Modiola plicatula/, typical form.] - - ^M. plicatula.^ This species of /Modiola/ ranges from Canada to - Hatteras, and inhabits the tidal waters of streams, sheltered - muddy reaches among reeds, and tidal flats. It is a dingy-looking - shell, ornamented with numerous radiating ribs, which are very - fine upon the anterior portion of the shell. The epidermis is thin - and of a dirty yellowish-green color. Within it is silvery-white. - In the ventral margin there is an opening for the accommodation - of a byssus. Length about three inches in New England; slightly - larger at Norfolk. There is probably no muddy reach of land that - is exposed at low tide from Maine to the Carolinas that is not - inhabited by /M. plicatula/. - - ^M. tulipa.^ This is the "show shell" of the genus /Modiola/ in - American waters. It belongs to the Southern fauna, and, like the - others of its genus, it moors itself to wood or other solid objects - by means of its byssus. It is of about the same size as the last - species, but is perfectly smooth and of a bright-yellowish color, - with dark rays over the central portion. - -[Illustration: /Modiola nigra./] - - ^M. recta.^ A species of /Modiola/ fairly abundant on the Pacific - coast from Vancouver to southern California. It has a long, narrow - shell with a dark-brown glossy epidermis; lighter posteriorly, and - with a short hairy growth. The interior is white. Length three to - four inches. - - -ORDER =PSEUDOLAMELLIBRANCHIATA= - -This third order of /Pelecypoda/ is made up of a number of families -in which the gills are filamentous, but in which the filaments -[pg430] have become united at their ends to the mantle (on the outer -gills) and to the body-mass (on the inner gills). Here also the first -traces of the higher type of gill found in the next order appear; -that is, a gill in which the filaments are connected by vascular -channels instead of by cilia. This order therefore is presumed to -connect the true filamentous type of gill with the fully developed -lamellar type. As the filaments do not always fuse with the mantle -or foot, the description of the pseudolamellibranch gill becomes -somewhat vague, and there is some room for doubt whether this order -should exist at all. - -Most of the genera placed in it are monomyarian; that is, they have -but one adductor muscle, or if two, the anterior one is very small -and unimportant. The mantle-edges are entirely open, there being no -regularly formed siphons. As a rule, the foot is exceedingly small or -quite aborted. - - -FAMILY ~AVICULIDAE~ - -In this family there is an exception to the rule just stated: the -foot is long. There is a byssus, and the gills (by their outer -ascending filaments) are concrescent with the mantle. - -The interior of all the /Aviculidae/ is of a highly polished nacre, -and some of the larger species have been extensively collected -for mother-of-pearl. To the /Aviculidae/ belong the pearl-oysters -(/Meleagrina margaritifera/). - -A delightful air of romance and adventure surrounds the -pearl-fisheries, about which much has been written. The pearl -is an abnormal product formed by the deposition of nacre around -some foreign object, such as a grain of sand, or--usually, it is -said--an egg which has failed to develop properly. They are seldom -found in individuals having favorable conditions of growth, but -those which are greatly crowded together and covered with various -parasites and growths are most productive of them. The pearl is -the same in substance as the nacreous shell of the pearl-oyster, -and its iridescence is due to the fine striae of the undulating -layers of which it is composed. The pearl as well as the shell -is produced by the shell-glands of the mantle. The value of the -[pg431] pearl is based on the brilliancy of the nacre, the size, -and the form. Luster, or "orient," is to the pearl what brilliancy -is to the diamond. The round form has the greatest value, next -the pear-shape, and lastly the oval. Pearls of inferior value are -produced by other species than /Meleagrina margaritifera/, the true -pearl-oyster. Many bivalves secrete similar bodies, but as they have -the nature of the shell, those produced by mollusks having lusterless -interiors are of no value. Beautiful pink pearls are found in the -gasteropod /Strombus gigas/, the conch-shell of the West Indies. The -shells of the pearl-oyster are themselves very valuable, being the -"mother-of-pearl" used in the manufacture of buttons, knife-handles, -inlay-work, and so on. They have three grades of commercial value; of -the first are the "silver-lipped," from the South Seas, of the second -the "black-lipped," from Manila and Ceylon, and of the third the -"bullock-shells," from Panama. - - -GENUS ^Avicula^ - - ^A. atlantica.^ A Floridian species which is often found attached - by its byssus to large algae which have been washed upon the beach. - The shell is reddish-brown, with many white radial lines. Its - obliquely oval shape, the long wing-like extension of the dorsal - margin, the inequivalve shells, and the byssal sinus placed just - below the forward extension of the hinge, are characteristics which - will enable one to recognize the species at once. The structure of - the shell is unusual in being so largely composed of organic matter - that it possesses elasticity near its thinner edges. - - -GENUS ^Pinna^ - - ^P. muricata^ and ^P. seminuda^. Two species of this family which - are very abundant in Floridian waters and are often to be found - associated upon the muddy or sandy shores of bays. Like /Modiola - plicatula/, they attach themselves by means of their byssus to - shells or stones which lie under the surface. With the pointed end - of the shell directed downward, they remain almost wholly concealed - in the sand. Only about one quarter of an inch of the broad end - of the shell projects above the sand. The edges of the valves are - as sharp as knife-blades, and great caution must be used while - walking barefooted along a beach inhabited by /Pinna/. The shells - of both species are of a triangular wedge-shape and are composed - of a translucent crystalline matter. /P. muricata/ is beset with - triangular erect scales which project out like spines. Their edges - are also sharp like pieces of broken glass. /P. seminuda/ also has - these raised scales, but they are far more numerous [pg432] and - much smaller, and are arranged in closely packed radiating rows, - the scales becoming obsolete near the umbones. The mantle of the - animal is doubly fringed, and much decorated upon that portion - which may be protruded from the shell. The posterior adductor is - very large and strong; the anterior one has almost disappeared. The - foot is long and slender, but is evidently a useless appendage, - for the animal's habit is stationary. The byssus is large and very - strong. Gloves have been made from the byssal fibers of /Pinna/ - mixed with silk. The gills are very long and are distinctly /not/ - filamentous, the adjacent filaments being clearly united by - vascular channels. A very curious development of the osphradium - (see page 339) into an erectile process capable of projection - beyond the margin of the shell is a unique feature of /Pinna/. - Sometimes thousands of pinnas are torn loose by storms and cast - upon the beaches. They do not range north of Hatteras. (Plate - LXXIX.) - - -GENUS ^Perna^ - - ^P. ephippium.^ A West Indian shell, also quite common on the - east coast of Florida, and especially upon the Keys. It attaches - itself by the byssus in great bunches to mangrove roots, sticks, - and all manner of rubbish in brackish water. It has a very flat, - irregularly shaped shell of a horn-color, and is from two to - three inches across. The distinguishing feature of /Perna/ is the - hinge. It is straight and without teeth, but is marked by a row of - transverse grooves to which the ligament is attached. These grooves - constitute a row of cartilage-pits. - - -FAMILY ~OSTREIDAE~ - -This family probably interests more people than any other one in the -class save /Aviculidae/. The latter furnishes the pearl-oysters, the -former the edible oysters, the two thus appealing to two very strong -human cravings--those of vanity and hunger. - -[Illustration: PLATE LXXIX. Pinna muricata. Pinna seminuda. Pecten -hastatus.] - -Few realize what an enormous business the oyster trade has become -in the United States. The value of it is stated to be over thirteen -million dollars annually, twenty-five million bushels of oysters -being taken from the Chesapeake alone. The edibility of the -oyster has been known from early times, for vast heaps of empty -oyster-shells, known as kitchen-middens, occur in various parts of -the world. Some of them are of such size and extent as to warrant -the belief that their formation must have required centuries. -Shell-mounds are found along the coasts of Florida and are of some -archaeological value. The cultivation of oysters as recorded by Pliny -dates from the first century B.C., at which [pg433] time a Roman -named Sergius Orata first cultivated oysters at Baiae. The acuteness -of the gastronomic sense of a Roman epicure is thus described by -Juvenal: - - He could tell - At the first mouthful if his oysters fed - On the Rutupian or the Lucrine bed - Or at Circeii. - -The poet Gay's opinion is expressed thus: - - The man had sure a palate cover'd o'er - With brass or steel, that on the rocky shore - First broke the oozy oyster's pearly coat, - And risk'd the living morsel down his throat. - -The methods employed in oyster-farming resemble those of agriculture, -in that the bed is prepared, seed is sown, superfluous and foreign -growths are weeded out, enemies are driven off, and the crop is -harvested at stated seasons. The oyster is ovoviviparous; that is, -it retains its eggs until they are partly matured. These are held in -the gills and mantle folds until the time of spawning, which begins -in May and lasts through the summer months. The larvae are ejected as -ciliated spheres, called spat, and swim freely about for some time, -often several days, before finding a resting-spot. The oyster-grower -secures many of the larvae by placing in their way substances to -which they can attach themselves. The American culturist strews his -carefully prepared beds with empty oyster-shells, on which the spat -settle, and the seed is thus secured; for the spat, once fastened, -lose the power of locomotion and become fixed. At the end of a year -the shells which hold the young oysters (now about an inch long -and called "fry") are taken up, and the fry are thinned out and -replanted, or are sold to other oyster-farmers. - -During the period of their growth the oysters are sometimes -transplanted several times. At the end of three to five years they -have attained marketable size, and the beds are then harvested and -prepared for another crop. Some oystermen have several acres of -bottom under cultivation. These areas are obtained by purchase or -grant from the State, and their limits are as defined [pg434] as -are the fenced-off acres of upland meadows. The business of the -oyster-culturist is to plant the young oysters and watch their -development, keeping the beds thinned, that the oysters may not be -too crowded for their normal and symmetrical growth, and protecting -them from their enemies, of which there are many. The principal -enemies of the oyster are the starfish and the predaceous mollusks -/Urosalpinx/ and /Nassa/. Whole beds have been known to be destroyed -in a single night by the visitations of starfishes, hence a constant -watchfulness is required on the part of the oysterman. Policing the -oyster-farms is another of his cares, for pirates abound, and a bed -may be robbed in the night as easily as an orchard may be despoiled -of its fruit. Oyster-culture is carried on extensively in Long -Island Sound, on the coasts of New Jersey and Virginia, and in the -Chesapeake Bay. The oysters from certain localities are esteemed more -than others, the flavor of the oyster being very dependent upon the -purity of the water and on the organisms upon which it feeds. It has -been definitely shown that oysters grown in contaminated waters have -been the agents of transmitting disease, notably typhoid fever and -cholera. - -Oyster-culture has reached the highest degree of perfection in -France, where miles of muddy shores left by the ebb-tide are utilized -for the purpose. The famous /parc/ at Arcachon, covering ten thousand -acres, illustrates the system generally practised. The spat is there -collected on tiles coated with cement, piled in layers crosswise, and -secured in crates. These tiles are exposed in favorable localities -and collect the swimming embryos. The rough cement holding the -spat is then chipped off the tiles and placed in wire trays. These -/ambulances/, or /caisses ostreophiles/, placed between short posts, -protect the fry from their enemies. At low tide the young oysters -are carefully examined and sorted, and at the right age they are -removed to open areas. The parc is divided into regular squares by -canals of suitable width, some of the squares having banks and gates -to retain the water of the receding tide if desired. Each man's parc -is separated from that of his neighbor by canals of greater width, -and often by stakes having a few branches on the ends. These [pg435] -/pignons/, which sway in the wind, are said to frighten away the -predaceous ray which is apt to hover about the preserves. The parcs -are finally thinned out by sending the oysters to other parcs to be -fattened. There is a celebrated /parc d'elevage/ at Marennes. It is -a collection of artificial ponds, the floors of which are covered -with algae, which harbor vast numbers of diatoms and other microscopic -organisms on which the oysters feed. The green diatom (/Navicula -ostrearia/) gives to the oysters of Marennes the green color and -peculiar flavor which is so much esteemed by the epicures of France. -To the American, however, the green oyster is not acceptable. - - -GENUS ^Ostrea^ - - ^O. virginica.^ A description of this species, our common oyster, - is hardly necessary. Every one has seen the rough, shaggy, unlovely - shell. The hinge is toothless, but has a wide depression for the - ligament. The animal, having stationary habits, has practically no - foot at all. There is but one large adductor muscle, around which - curve the gills, the latter being united to each other posteriorly. - The mantle margin is finely and doubly fringed. Although /Ostrea/ - is a stationary mollusk, it has no byssus. - - /O. virginica/ has been introduced at San Francisco, where it - lives well, but does not seem to multiply very rapidly. The native - species, ^O. lurida^, is about two inches long, dark in color, and - stained a purplish hue. It is not very delicately flavored. - - ^O. frons.^ This species has a thinner shell than /O. virginica/, - with coarsely serrated margins. It occurs in beds in the - neighborhood of mangroves all along our South Atlantic shores. It - cannot compare with its Northern relative in flavor, but, like the - European ^Ostrea edulis^, it is sometimes "not bad." - - -FAMILY ~PECTINIDAE~ - - -GENUS ^Pecten^ - -The scallop-shells (/Pecten/) are objects too familiar to require -any general description. The rounded valve, usually ornamented with -radiating ribs, and the wing-like projections (called "ears"), from -each side of the umbonal region, are never-failing characters. The -outline of /Pecten/ has been considerably employed in conventional -designs for mural decorations; indeed, the figure [pg436] of a -well-known Mediterranean pecten (/P. jacobius/), found commonly -in Palestine, became an emblem of religious significance during -the middle ages. Returning crusaders fastened to their garments a -specimen of "St. James's shell" as an evidence of the fact that they -had been to the Holy Land, and the design of the shell came to be -adopted upon many coats of arms and also in the insignia of various -orders of devout and adventurous knights of the middle ages. - -The animal is of the highest type of monomyarian mollusks, that is, -of bivalve mollusks with only a single adductor muscle. Unlike most -pelecypods, which have a very small foot, /Pecten/ rarely has a -byssus, and is neither a stationary nor a sluggish creature. It can -propel itself through the water by spasmodically closing and opening -its valves, in an eccentric, darting sort of flight, though most of -the time it rests quietly upon the bottom. The mantle is entirely -open and highly ornate about its margin, which is, furthermore, the -seat of many eyes, capable, apparently, of no mean degree of vision. -The adductor muscle is very large and strong, and occupies a central -position, about which the gills circle; the latter are plainly -filamentous. - - ^P. magellanicus.^ The largest of the east-coast species of - /Pecten/. It is a Northern species, and was long known by the - name of ^P. tenuiscostatus^--a name given to it on account of - its very numerous radiating striae; but it was later discovered - that the North Atlantic form was in reality the same as the /P. - magellanicus/ of Patagonia. The latter being the older name and - entitled to priority, our shell became /P. magellanicus/, the - other name falling within its synonymy. The length and height of - this scallop are from five to five and a half inches. One valve - is more convex and slightly larger than the other, the smaller - being lighter in color. The valves gape considerably along their - upper margin below the hinge. The cartilage-pit is deep. North of - Cape Ann this large species is of common occurrence in moderately - deep water. The deeper bays and arms of the sea which everywhere - penetrate the Maine coast are its favorite resorts. A good way - to catch pectens is to lower a fishing-line at a spot where the - fishermen report "scallop-ground," and drag it along over the - bottom. Sooner or later it will enter the open shell of some - pecten, which will instantly close its valves upon the string and - allow itself to be drawn out of the water. In Maine these large - scallops are eaten, but they have not found great favor in the city - markets. In color they vary from reddish through brown to ashen. - - ^P. islandicus.^ A species not so large as the last, with more - prominently raised ribs (about fifty to one hundred in number), - which are [pg437] covered with a multitude of erect scales. The - ribs persist upon the interior of the shell. The "ears" are unequal - in size. The color is light orange to reddish-brown, with zones of - darker and richer color. One valve is flatter than the other and - more lightly colored. Greatest length about three inches; height - three and a half inches. This is a Northern shell, belonging to the - waters of Newfoundland, but its valves are frequently cast upon the - New England beaches. - - [Illustration: /Pecten islandicus./] - - ^P. irradians.^ The common shallow-water species of the Atlantic - coast. This exceedingly abundant species does not range north of - Boston, but finds an extensive habitat to the south. Its metropolis - is Cape Cod, Long Island Sound, and the Jersey coast waters. This - is the true scallop of the Boston and New York markets. Only the - adductor muscle is eaten. In this species there is not so marked - a difference in the convexity of the two valves. There are about - twenty elevated and rounded ribs, the spaces between them being - also rounded. The color is variable, from a blackish horn to ashen - gray. The "ears" are equal; the interior is shining, and grooved - to correspond with the external ribs. Length two and three fifths - inches, height two and a half inches. On clear, calm days the - immature individuals of this species may often be seen in shallow - water disporting themselves most gaily, skipping about and snapping - their valves in great glee. Their mantle margins are very ornate - in scarlet or orange, with rows of bright-blue eyes. Care must be - taken in handling scallops, especially the large /P. magellanicus/, - for a finger caught between the valves will be badly bruised. - - ^P. dislocatus.^ South of Hatteras this species takes the place of - its Northern relative, /P. irradians/. It is somewhat more globular - and perhaps not quite so large, but the resemblance between the two - species is very marked. It has from twenty to twenty-two rounded - ribs, with very numerous concentric wrinkles between them. In - color it is white, tinged with purple or yellow, with occasionally - a system of blood-red lines crossing the ribs transversely. The - diameter is about one and a half inches. This species has the - same playful habits as /P. irradians/, and is not at all easy to - capture. When pursued it dives into the mud, and sets up such a - commotion by the spasmodic opening and shutting of its valves that - the water at once becomes roiled, and the scallop is safely hidden - in its murky depths. [pg438] - - ^P. hastatus.^ There are several very beautiful pectens on the - Pacific coast of the United States, and two of these--one of - northern and the other of southern range--resemble very closely - the two Atlantic species of relatively north and south range, /P. - islandicus/ and /P. irradians/ or /dislocatus/. The first is /P. - hastatus/ of Puget Sound. Valves of this exquisite shell are even - occasionally found in California. It has very much the aspect of - /P. islandicus/--unequal ears and an ovate form. The most curious - thing about this shell is the fact that a different system of - sculpturing exists upon the two valves. Upon one the ribs are even - and the whole surface is covered with raised scales; upon the other - the ribs are alternately of large and small size. Color rose-pink, - with deeper bands; one valve lighter-colored, suffused with - delicate pink. Height two and a half inches. (Plate LXXIX.) - - [Illustration: /Pecten irradians/, typical form.] - - ^P. aequisulcatus.^ The Southern species above referred to as - resembling /P. irradians/ or /dislocatus/. It has about twenty - stout, well-rounded ribs, with concentric wrinkles between - them. The "ears" are equal. The size and shape are as in /P. - irradians/. The coloring is whitish, varying to shades of brown, - and excentrically marked with spots or waving transverse lines of - chestnut or horn. - - -ORDER =EULAMELLIBRANCHIATA= - -With the pectens we leave behind all pelecypods with the true -filamentous type of gill. In the order /Eulamellibranchiata/ we find -all the families to be possessed of the basketwork or crisscross -branchial structure. Each gill is fundamentally formed of filaments -which project downward, and then suddenly turn upon themselves and -ascend; the ascending and descending limbs are connected, however, by -processes of presumably vascular function, and adjacent filaments are -connected by truly vascular channels. The closer connection of the -filaments to form of each gill a sort of plate is further effected -[pg439] by connective tissue, which sometimes is dense enough (though -always porous) to obscure the reticulated appearance of the organ. -Furthermore, the edge of the outer lamella of the outer gill unites -with the mantle; likewise the edge of the inner lamella of the inner -gill unites with the body-mass, and /behind the body-mass/ with the -gills upon the other side of the animal. This union of the four gills -in a straight median line behind the foot and body-mass forms a -septum, which divides off from the mantle cavity a "suprabranchial" -cavity. Into this cavity the excreta are discharged, and with it the -anal or excurrent siphon connects. The branchial or incurrent siphon -thus pours its current of water into the /lower/ mantle cavity, to -bathe the gills and feed the mouth, while the fresh water is not -contaminated by any open and wide connection with the excretory -processes. In many of the forms where the siphons are very long and -united, this septum, formed by the union of the dorsal edges of the -inner gills back of the foot, is continued far into the siphons, -constituting the division of the two into the anal and branchial -siphons. - -Another feature of this order is the marked tendency to mantle -fusion. As there are always siphons, the mantle-edges must -necessarily have fused at two points at least, in order to have -formed the siphons. The tendency, however, is for the fusion to -continue, narrowing the pedal opening more and more, as though the -mantle were endeavoring to envelop the entire animal in a bag or sac -open only at one end (siphonal opening), but yet slightly ripped -along one seam (pedal opening). - -This order includes the great majority of pelecypods, and admits of -many very confusing modifications in its most essential features. - - -FAMILY ~CARDITIDAE~ - -In this, the first family of the order, most of the characteristic -features just spoken of are present. Mantle fusion, however, has -not progressed beyond a degree which is just sufficient to form the -siphons. There is a byssiferous gland. The name /Carditidae/ refers to -the heart-shape of the shells. [pg440] - - -GENUS ^Cardita^ - -[Illustration: /Cardita borealis/, natural size.] - - ^C. borealis.^ A very common species north of Cape Ann, reported - also in deeper water as far south as Hatteras. It is a solid, - obliquely heart-shaped shell, with beaks elevated and turned - forward. It has about eighteen to twenty rounded radiating ribs, - which are broader than the grooves between them. The epidermis - is rusty-brown. The hinge is strong, with two prominent teeth; - the margins of the shell are strongly crenulated within. - Length one inch; height about the same. This is not strictly a - between-the-tides species, but its valves are often cast upon the - beaches. Fine specimens may be obtained by dredging at Bar Harbor - or Eastport. - - ^C. floridana.^ A very common Floridian species. Its seventeen or - eighteen ribs are very heavy, and are rendered nodulous by the - numerous bluntly raised scales upon them. The shell is lengthened, - and has a well-defined lunule and an external ligament. In color - it is yellowish-white, with purple markings when young. Length one - inch; height three fourths of an inch. It lives in sheltered bays; - detached valves are often found cast upon the beach. - - -FAMILY ~ASTARTIDAE~ - - -GENUS ^Astarte^ - -Notwithstanding their rather small size, there is a trimness about -the shells of /Astarte/ which, taken together with their rich -chestnut epidermis, makes them very interesting and desirable -additions to the cabinet. The family is one of cold-water range, with -a few representatives on the New England coast. Live specimens are -not easily captured, for they live in deeper water than one would -care to wade in, nevertheless they are frequently cast upon the -beaches after storms. The animal has a very short efferent siphon, -large labial palps, and very obliquely placed gills. Not more than -twenty living species of /Astarte/ are known, and all of them belong -in, or are wanderers from, polar seas. Fully three hundred fossil -species of this genus have been described from Mesozoic rocks in all -parts of the world. The question naturally arises whether in these -its dying days /Astarte/ has sought colder waters in which to pass -its remaining existence, or whether climates have changed. The fact -that such strictly [pg441] tropical genera as /Voluta/ and /Conus/ -are found fossil in northern Siberia seems to be evidence in proof of -great climatic variations. - - ^A. castanea.^ This species has a thick and heavy shell for one - so small, with round ventral margins and prominent beaks. The - surface is very slightly undulated and is covered with a thick - chestnut epidermis with pale and dark zones. The hinge is broad and - flat, with a prominent cardinal tooth upon the right valve, which - accurately fits into a pit formed by two teeth on the left valve. - Length one inch; height one inch. - - [Illustration: /Astarte castanea./] - - ^A. undata.^ A species slightly larger than the last, with ten to - twenty prominent concentric undulations. - - [Illustration: /Astarte undata./] - - The identification of the many species of /Astarte/ often becomes - exceedingly difficult on account of the fact that the genus is a - remarkably uniform one in its main characters and is infinitely - variable in its minor details. - - -FAMILY ~CYPRINIDAE~ - - -GENUS ^Arctica^ - -This family is represented by one species upon the New England coast, -which is much sought after by collectors. It is one of the larger -clams, but is too uncommon to have received a popular name and to be -generally well known by the fishermen along the shore. - -[Illustration: /Arctica/ (/Cyprina/) /islandica/.] - - ^A.^ (^Cyprina^) ^islandica^. This clam has a thick though not - ponderous shell, with prominent beaks and a stout, prominent - ligament. Its cardinal teeth are large, but its laterals are very - small. A striking feature of this species, which at once separates - [pg442] it from all other shells of our coast of similar size, - is the coarse, wrinkled epidermis of black to chestnut color. - The shell is very suggestive of a large, overgrown /Astarte/. - Length three and a half inches; height three inches. It is found - of all sizes, down to one fourth of an inch in diameter, upon - muddy stations in moderately deep water near the mouths of rivers; - but the surest way to get it is to search the beach after a hard - onshore gale. - - -FAMILY ~LUCINIDAE~ - -This family finds its metropolis in warmer waters, and the best -representatives of it must be sought for upon the Floridian beaches -or in the shallow bays of that sandy coast. A long vermiform foot -is a characteristic of the animal, as is also the fact that at -times there is only a single gill upon each side of the body. In -some of the /Lucinidae/, more so than in most other pelecypods, the -chief function of the gills is to furnish a brooding-place for the -thousands of ova which the creatures generate. Sometimes a /Lucina/ -will be captured with the gills swollen out of all proportion, -and literally stuffed with tiny, microscopic eggs. At such times -the gills lose all semblance of branchial organs. The shells are -orbicular, with depressed small umbones, a distinct lunule, a -semi-external ligament, two cardinal teeth, and laterals (a variable -feature). There is no pallial sinus. The color is white, and the -outlines are rounded. - - -GENUS ^Lucina^ - - ^L. tigrina.^ The largest of the group, measuring three inches - across and nearly the same in height. It is flatly convex and - radially ribbed by a great number of costae which are crossed and - decussated throughout with concentric ridges. The color is white. - This fine shell lives only in southern Florida and is abundant in - shallow water on sandy stations. (Plate LXXX.) - - ^L. floridana.^ One of the most abundant bivalves in Florida, often - cast in thousands upon the beaches. It lives in shallow protected - waters and upon sand-flats which are partly exposed at low tide. - It has the usual round outlines of the genus, with exceedingly - small umbones, directed forward, and a smooth surface, save for - fine growth-lines of a light straw-color. The shell is pure white. - Diameter about one inch. (Plate LXXX.) - - ^L. pennsylvanica.^ A species often associated with the last, - but about twice as large. Its thin but tough epidermis clings - to the shell in raised concentric lines, giving it a circularly - ribbed appearance. The most prominent feature of this species is - a depressed line upon either valve extending obliquely from the - umbones to the posterior ventral margin, [pg443] causing, at the - margin, a pucker or break in its even continuity. The lunule is - large and ribbed; the teeth are small; the color is pure white, - with a light straw-tinted epidermis. (Plate LXXX.) - - ^L. dentata.^ In this species the shells are thin and white, with - well-marked concentric lines crossed by deep oblique narrow furrows - bent at nearly right angles to the lines of growth and forming - teeth around the margin. Found along the entire coast. - - [Illustration: /Lucina dentata./] - - ^L. californica.^ The best-known California species of this genus. - It is pure white, with fine concentric lines, and varies in size - from one half of an inch to one and a half inches in diameter. The - lateral teeth are the stronger, and the lunule is upon the right - valve only. With these exceptions this species preserves the usual - characters of this genus. - - ^L. nuttallii^, belonging to the southern shores of California, is - decussated like fine wickerwork. The shell is flattened and ridged - along the hinge-margin. The color is white. Diameter about one inch - in large specimens. (Plate LXXX.) - - -GENUS ^Loripes^ - - ^L. edentula.^ A species which is seldom captured alive. Its - home is in the open sea, but vast quantities of its valves are - occasionally thrown upon the beaches south of Hatteras, as far as - the Gulf of Mexico. On account of the weak hinge ligament, the - valves become easily separated, and it is not always easy to find - two that will exactly match. /Loripes/ preserves the same circular - outlines as /Lucina/, but is more ventricose, and the hinge and - teeth are very feeble. This species is a little over two inches in - length and slightly under two inches in height. It is pure white - without, and is finely striated with growth-lines; bright orange - within, especially about the pallial line and muscle-scars. (Plate - LXXX.) - - -FAMILY ~TELLINIDAE~ - - -GENUS ^Tellina^ - -If we should create an aristocracy of beauty among the bivalves, as -has been done by conchologists among the gasteropods, this family -would deserve high rank. Most of the American species of /Tellina/ -are too small to impress one very greatly with their beauty, but -in the West Indies and in the tropical Pacific waters are some -wonderfully handsome shells belonging to this or to the allied genus -/Macoma/. However, we have in Florida the very striking /T. radiata/, -a truly beautiful shell, which, were it less common, would be highly -prized in collections. Rarity, no doubt, adds a wonderful luster -to shells as well as to gems. The [pg444] animal of /Tellina/ has -long, slender siphons, which are separate. The gills are small, and -the outer lamella or branchial fold is directed dorsally. Although -the foot shows evidences of a byssogenous gland, there is no actual -byssus. The shells are porcelanous and translucent, equivalve, with -an external ligament, and at least two cardinal teeth in each valve. - - ^T. radiata.^ This species varies from three to four inches in - length, and from one and a half to one and three fourths inches - in height. It is highly polished, shining white, and yellowish - about the umbonal region, and has three wide rays of bright pink - extending from the beaks to the ventral margin. On account of its - remarkable coloration it is called the "setting-sun shell." Its - surface is smooth. A common variety is of a uniform creamy-white - color with carnation beaks. This shell is always offered for sale - by the marine curio- and shell-dealers in Florida seaside resorts, - and at Atlantic City, Cape May, and elsewhere. - - ^T. alternata^ resembles the last in shape, being flattish and - oblong, but it is more pointed or angulated posteriorly. There is - also a slight twist in the posterior end of the shell. Its surface - is decorated by numerous impressed concentric lines. The color is - uniformly white or yellowish, with pink rays. Length two and a half - to three inches; height two and a half inches. Found from Hatteras - to the Gulf of Mexico, in shallow, sandy stations and on beaches - after storms. (Plate LXXXI.) - - ^T. bodegensis.^ The most striking species of /Tellina/ found on - the west coast, and of rather northern range. It is about two - inches in length, creamy-white in color, and ornamented with very - fine concentric lines. A very characteristic feature of the genus - is present in this species as in the last, namely, a slight twist - or bend to one side in the posterior end of the shell. - - [Illustration: /Tellina tenera/, showing extended animal.] - - [Illustration: /Tellina tenera./] - - ^T. tenera.^ A little /Tellina/ found in New England waters, which, - though very small, is worthy of mention on account of its abundance - upon all our beaches north of Hatteras. It is only about half an - inch long, and slightly over one quarter of an inch high. It may - be distinguished by its general generic characters, its iridescent - surface, and its delicately marked lines of growth; sometimes - it is rose-tinted. Its remarkably long siphons are shown in the - accompanying figure. - - -GENUS ^Macoma^ - - ^M. secta.^ A very pretty thin glossy shell from two to three - inches in length and about one fourth less in height, which - occurs from Monterey southward. The posterior end of the shell is - contracted and slightly bent; the pallial sinus is deep. There is - an external ligament. (Plate LXXXI.) - - [Illustration: PLATE LXXX. 1, Lucina tigrina. 3, Lucina - pennsylvanica. 2, Lucina floridana. 4, Lucina nuttallii. 5, Loripes - edentula.] - - [Illustration: PLATE LXXXI. 1, Tellina alternata. 3, Donax - variabilis. 2, Macoma secta. 4, Donax californicus. 5, Raeta - canaliculata.] - - ^M. nasuta.^ Another Californian species, with a less shining - surface and a very thin light-brownish epidermis. The twisting of - the posterior [pg445] margin is striking. It has very fine - cardinal teeth. Length two to three inches. - - ^M. baltica^, ^M. proximo^, ^M. tenta^. The first two of these - species are dingy in color, and are covered with a dirty-looking, - thin epidermis. The first has a wide range to Norway and Scotland, - and is exceedingly common all along our coast from Maine to - Georgia. It occurs plentifully in the Hudson River above New York, - and in all sandy or muddy bays. It is rounded in outline, while the - next species (/M. proxima/) is more pointed posteriorly. When these - species are buried in the sand their two long, slender siphons - project above, one supplying the animal with a constant current - of fresh water, and the other ejecting that which, having passed - the gills and labial palps, is exhausted of its air and nutriment - and contaminated by waste products. /M. tenta/ is white, with very - fine lines of growth, and polished and shining within. It is warped - posteriorly. Length three fifths of an inch; height two fifths of - an inch. - -[Illustration: /Macoma baltica./] - -[Illustration: /Macoma tenta./] - - -FAMILY ~DONACIDAE~ - - -GENUS ^Donax^ - -The /Donacidae/ are represented upon our coasts by comparatively -few species, all belonging to the genus /Donax/. The shells are -under an inch in length, and have a peculiarly shortened anterior -portion; thus they are inequilateral. Their ventral margins are -finely denticulate. The pallial sinus is deep. There are two or three -cardinal teeth and a variable number of laterals. - - ^D. variabilis.^ This little shell, the common Floridian form, - exhibits every imaginable scheme of color-combination, and defies - general or comprehensive description. Probably the most usual - pattern developed is a bluish-white background with purplish - radiating lines. Another is a pure-white foundation with red - lines. The surface is striated longitudinally with excessively - fine riblets. Length one half of an inch or slightly more. In - March and April these shells are thrown alive in millions upon the - Florida beaches. Each wave seems to be laden with them, and when - the foaming waters of each spent breaker recede, the little shells - lie still upon the sand for a moment, glittering like jewels in the - sunlight; then, with a sudden protrusion of the foot and a quick - turn, they all disappear like a flash, buried in the sand before - the next breaker strikes them. One must be very quick to catch - these active little mollusks. (Plate LXXXI.) - - ^D. californicus.^ Professor Keep very aptly describes this shell, - which is very common in California, as "short and stumpy, cut - nearly square off at one end (anterior), and tapering to a rounded - edge at the other." The same description fits both this and the - Floridian /D. variabilis/ so well that the two forms may be one - and the same species. [pg446] If they were shells of arctic - range it would be easier to connect them; but as neither is a - cold-water form, it becomes more difficult to place them under one - name. The increasing number of similar species being found upon - the Atlantic and Pacific sides of Central America points almost - conclusively to the existence of a waterway between the two oceans, - somewhere between North and South America, at no very remote - geological period. Possibly the closing of some such waterway - through the isthmus connecting the oceans has separated these forms - geographically, thus leading us to separate them specifically. - (Plate LXXXI.) - - -FAMILY ~MACTRIDAE~ - -This is a very large family of universal distribution and with a -great number of genera and subgenera, rather confusedly gathered -into subfamilies. The dominant genus /Mactra/ comprises the largest -bivalve upon the east coast of the United States. - - -GENUS ^Mactra^ - -The mactras live in the sand near the margin of the water, often -upon the exposed open coast. The mantle is open, except where it is -fused to form the siphons. These are short and united. The outer gill -is dorsally directed; that is to say, it does not depend into the -mantle cavity as does the inner gill, but projects just the other -way; it is also smaller than the inner one. The foot is strong, -bent, and tongue-shaped, and no doubt well adapted to the rough life -in the surf and the heavy, shifting sands. The main characteristic -of the mactra shell is the prominent triangular-shaped fossette, -or cartilage plate, situated internally and just under the beaks. -The shells are equivalve, and devoid of bright colors or striking -sculptural features. Internally the pallial line is plain, and the -sinus well marked but not deep. - -[Illustration: /Mactra solidissima./] - - ^M. solidissima^ is one of the very commonest, if not the - commonest large bivalve of the New England, Long Island, and New - Jersey [pg447] beaches. It is covered with a thin brownish or - straw-colored epidermis, usually more or less worn away in adult - specimens and wholly absent from the dead valves found upon the - beaches. There is a fragile V-shaped cardinal tooth, which is - generally broken away in forcing open the valves; the lateral teeth - are long and thin, and striated on their receiving surfaces. The - length of this "giant clam" is from four to seven inches. This is - the first shell the collector will find (north of Hatteras) when he - goes to an open, sandy beach. - - ^M. similis.^ A small variety of the species last described, of - similar outline, but less heavy and strong. Its range is from - Hatteras southward to Brazil. Passing from New Jersey to Hatteras, - /Mactra solidissima/ diminishes in size, and after passing that - faunal barrier the Northern form is entirely replaced by this - Southern variety. The shell is brighter, though not exactly - bright-shining. Its habits are entirely similar to those of the - Northern form. On the west coast of Florida it is the most abundant - bivalve upon the beaches. - - ^M. ovalis.^ A species of Northern range, which so greatly - resembles /M. solidissima/ as to suggest identity; but the lateral - teeth are smooth and not striated, while the shell itself seldom - attains a length of over four inches. - - ^M. lateralis.^ An exceedingly common shell, found in all the - salt-marshes and tidal estuaries of our coast. It is much smaller - than the mactras just described, being not over one half of an - inch in length. It is white, and is covered with a dirty brown - epidermis; the hinge is strong, with deep cartilage fossette and - a V-shaped marginal tooth. The laterals are long and slender. The - animal has a strong foot and two slender, long siphons which are - yellow in color. - -[Illustration: /Mactra lateralis./] - - -GENUS ^Raeta^ - - ^R. (Labiosa) canaliculata.^ In this species the cartilage fossette - is the same as in /Mactra/; the marginal teeth are feeble, and - there are no laterals. The shells of /Mactra/ which we have - examined are heavy or at least solid, but /Raeta/ is thin and - fragile; it is pure white in color and is gracefully ornamented by - concentric raised ribs. The shell is inflated and gapes slightly - posteriorly; it is shining white within and is deeply grooved - concentrically in accordance with the external ribs. Length two - and a half, height two inches. From Hatteras to Mexico, this is - one of the commoner beach shells, but since, as in some other - species already named, the hinge ligament and teeth are feeble, the - valves become separated by the buffeting of the waves, and are cast - disjointed and singly upon the beaches. (Plate LXXXI.) - - -FAMILY ~VENERIDAE~ - -In many respects this is the most distinguished pelecypod family. -It is the largest in number of genera and species, is of world-wide -distribution, and supplies to hungry man a number [pg448] of -comestible species. Several of its genera have been named after -various goddesses and nymphs on account of the great beauty of -their shells. But from a purely biological point of view also the -/Veneridae/ have claims to distinction, for they seem to represent -about the highest type of shell-development among the bivalves. The -test is extremely hard and often porcelanous. It is solid without -being ponderous and unwieldy in the sense of causing the animal to -be helplessly overburdened by the sheer weight of its shell. The -valves are equal and have three stout cardinal teeth. The foot is -strong, the animal is active, the siphons are free or partially -united, and the gills are more or less crumpled and folded. There is -a compactness and well-regulated arrangement of the organs in the -/Veneridae/, which impress one who has examined the anatomy of many -pelecypods much as a well-built, efficient, and space-economizing -machine would impress a mechanic. None of the organs are weak or -crowded out to furnish room for the undue or awkward development -of other organs. A good balance is preserved between them all, the -result being a high type of pelecypod. - -If we do not expect to find any of the more remarkable forms of the -/Veneridae/ upon our shores we shall be the less disappointed when -returning from collecting-expeditions. Nevertheless, there are a few -species of /Cytherea/, /Dosinia/, and /Tivela/ in North American -waters which are very handsome shells; but those of our species which -are included under the generic name /Venus/ are in point of beauty -not worthy of their promising name. - - -GENUS ^Venus^ - - ^V. mercenaria.^ This is the common "hard-shell clam," the "Little - Neck" of the hotels and restaurants, with which every one in New - York and New England is familiar. The species ranges from Cape - Cod to Florida, and occupies two different kinds of station: one - in shallow muddy bays near low-tide mark, in estuaries, etc.; the - other the sandy stations in open deeper bays or the open ocean. - Those coming from "outside" have thinner, more delicate shells, - with thin, concentric ribs. They burrow in the sand or mud, or - crawl quite rapidly. The siphons are short and are united almost - to their ends. The mantle is open (save for the siphons), and the - edges are delicately frilled. In the United States this species - is very extensively gathered for the markets. When the oyster - season closes in April, the hard-shell clam comes into vogue, the - season lasting until September or October. The clams are [pg449] - extensively gathered in the estuaries from Cape May to Cape Cod. - Men armed with rakes drift about in small boats and fish the - sluggish creatures up out of the mud. They will live for many days - out of water if kept in a cool place. Smaller or immature clams are - better for the table, since they are not so tough as their elders. - A few features of the shell of this species are noticeable--the - rather prominent umbones directed forward, the heart-shaped lunule, - the external ligament, the concentric sculpturing of growth-lines, - the pure-white interior (with occasionally violet zones about - the muscle-scars and margin), the three stout cardinal teeth, - the sharp-angled pallial sinus, and the ventral margin finely - crenulated within. The greatest length is about three inches and - the height two and a half inches, but these dimensions exceed those - of the clams usually served upon the half-shell. /V. mercenaria/ - ranges into Florida, increasing in size and bulk as it meets the - warmer waters of the Gulf Stream. The Floridian form has received - the varietal name of /mortoni/. This massive clam sometimes weighs - five pounds, and is fully six inches in diameter. Aside from its - great size and thickness, the characters of the shell are wholly - those of the smaller Northern form. It is abundant in shallow, - muddy, brackish bays, and is gathered by men who "tread out" the - clams, feeling for them in the mud and sand with bare feet. The - flesh is tough and disagreeably strong, yet the natives appear to - relish it, especially when it is made into a chowder. - -[Illustration: /Venus mercenaria/, typical form.] - - ^V. cancellata.^ The most abundant species of /Venus/ in Florida, - particularly near Tampa and on the west side. It preserves all the - characteristics of the genus, and is decorated with a series of - high, narrow, concentric ridges, between which are much smaller and - more numerous radiating riblets. The color is dirty white to light - yellow-brown without, and white and violet within. There are three - cardinal teeth and no laterals. The lunule is heart-shaped; the - posterior margin is broadened into a wide, concave area into which - the concentric ridges do not pass. Length one to one and a fourth - inches; height the same. Sometimes the beaches in Florida will in - places be banked up with the valves of this very abundant /Venus/. - As they live in shallow water upon sandy stations, they are easily - dislodged by the heavy storms which sometimes sweep that usually - placid coast. (Plate LXXXII.) [pg450] - - -GENUS ^Cytherea^ - - ^C. (Callista) gigantea.^ One of the most beautiful Floridian - shells. It is nearly or quite six inches long and about three and - a fourth inches in height. The shell is porcelanous, is covered - with a pinkish, livid epidermis, and is decorated with numerous - longitudinal color-rays of lilac. The rays are usually broken and - interrupted. Within it is china-white, and has a deep pallial - sinus. It is very abundant on the west coast of Florida, at Sanibel - Island, Egmont Key, Lake Worth, and on beaches. (Plate LXXXII.) - - ^C. maculata.^ This species is more oval in outline than the last. - It is of a fawn-color, blotched or waved with violet-brown, and - is porcelanous and shining. The epidermis is also shining and - corneous. Within it is china-white in color. The pallial sinus is - very deep and wide. Length two and a half to three inches; height - one and a half to two inches. This also is a shell to be looked for - upon the beach after storms, but it will probably not be seen on - the east coast of Florida, although it occurs on the Keys and also - at Hatteras. Both of the species have been used as food, but not - very extensively. The flesh is not lacking in tenderness, but it - has a peppery taste. (Plate LXXXII.) - - -GENUS ^Dosinia^ - - There are two species of this very graceful genus of /Veneridae/ - south of Hatteras, ^D. discus^ and ^D. elegans^. These dosinias - have united siphons. The foot is very large and strong, and the - mantle margin is both papillaceous and plicated. The shells of - these two species are about three or three and a half inches in - length and of the same height, and are very flat. The ventral - margin is almost a perfect circle, and the beaks are small and - pointed. The lunule is small and cordate; the valves are very - gracefully sculptured in fine, regular, impressed, concentric - striae, which are finer and less elevated in /D. discus/ than in - /D. elegans/; the shell is porcelanous and white, and is covered - by a straw-colored, very fine, transparent epidermis. Within, the - strong cardinal teeth are placed upon a long fossette. There is a - deep pallial sinus. /D. discus/ is characteristic of the east coast - of Florida, while /D. elegans/ is only found upon the west side of - the State. Both may be looked for upon the beach, though living - specimens must be captured with the dredge. (Plate LXXXII.) - -[Illustration: PLATE LXXXII. Venus cancellata. /Cytherea/ -(/Callista/) /maculata/. /Cytherea/ (/Callista/) /gigantea/. Dosinia -discus.] - - -GENUS ^Tivela^ - -The coast of California is also favored by the /Veneridae/, a number -of large species belonging to several genera being present. - -[Illustration: PLATE LXXXIII. Tivela crassatelloides, one half -natural size. Chione succincta. Tapes laciniata, one half natural -size. Chione simillima.] - - ^T. crassatelloides.^ Perhaps the largest and finest of the - California species. It is so common in its between-tides station - that it used to be collected by plowing a furrow through the - sand, the big shells being thrown out upon either side like - potatoes. The shells attain a length of five and a half inches, - and are porcelanous, thick, and heavy. The margins of the valves - are also thick and rounded. The exterior is perfectly smooth, - yellowish-white in color, and decorated [pg451] with purplish - rays arranged in various groupings; over all is a glossy epidermis. - The hinge-teeth are very strong, and a prominent anterior lateral - tooth on the left valve is noticeable. There is an external - ligament; the pallial sinus is well marked, but not very deep. - (Plate LXXXIII.) - - -GENUS ^Chione^ - -There are three species on the west coast. This genus is very closely -allied to /Venus/, and is considered by many to be only a subgenus of -the latter. All three species are white, solid, heavy shells which -exhibit the same scheme of sculpturing, namely, numerous longitudinal -ribs crossed by larger and less frequent concentric ridges. - - ^C. simillima^ is shaped almost exactly like the east-coast /Venus - cancellata/, but its concentric ridges are very numerous and sharp. - There is a strongly marked cordate lunule, and hardly any pallial - sinus. Length one and a half to two inches. (Plate LXXXIII.) - - ^C. succincta^ has fewer concentric ridges and has a large lunule. - There are purple zones within and touching the heavy cardinal - teeth. Length two and a half inches. (Plate LXXXIII.) - - ^C. fluctifraga^ has broad but flatter or well-rounded (not sharp) - concentric ridges, no lunule, a small ligament, a fairly deep - pallial sinus, and a finely crenulated margin (within) all around - the valves, except when interrupted by the hinge ligament. The - shell is solid and shining, and marked by deep-purple zones within. - Length one to two inches. Found in southern California. - - -GENUS ^Tapes^ - -This is a prominent genus of the /Veneridae/. Its chief feature is -the total want of lateral teeth. There are several large species in -California. - - ^T. staminea, T. laciniata.^ These are the most noticeable - species. The former is sold in the San Francisco markets as the - "hard-shell clam." The shell of this species is from two to three - inches in length and of somewhat less height, rounded, and heavy. - The sculpturing consists of radiating ribs traversed by strongly - marked growth-lines. The teeth are strong, and the pallial sinus - is deep. /T. laciniata/ is much like the last, but its surface is - reticulated by a crisscross design that is very striking. It also - has a deep pallial sinus. These two species are of Southern range. - They burrow in gravelly places, among stones, between tide-marks, - and their presence may frequently be detected when walking along - the beach at low tide by seeing a sudden jet of water ejected from - a little hole in the mud or gravel. The animal, becoming alarmed at - the approach of something, suddenly snaps shut its valves, and thus - forces out some water through its siphons. The foot is very strong - and often byssiferous in this genus. (Plate LXXXIII.) [pg452] - - -GENUS ^Saxidomus^ - - ^S. nuttallii.^ The last of the larger west-coast /Veneridae/ which - we shall examine. The genus is very closely allied to /Tapes/, and - no doubt might better be considered as its subgenus. The shell is - brownish-white, three to four inches in length, and heavy, rough, - and coarse-looking, with irregular concentric ridges. There is - no lunule, but a large external ligament is very prominent just - back of the beaks. Within it is white, with a deep pallial sinus. - Just below the ligament area is a zone of translucent, agate-like - shell-structure. This large clam, with several others of the same - genus, lives in shallow water near shore. - - -FAMILY ~PETRICOLIDAE~ - - -GENUS ^Petricola^ - - ^P. pholadiformis.^ Along the Jersey coast, especially about - Atlantic City, there are small patches of clay or hard tenacious - mud which lie just at the edge of the sea. As the beating of - the surf gradually encroaches upon these hard fragments of once - extensive clay-beds, many specimens of this curious bivalve mollusk - are washed out from their burrows in this clay and cast upon the - sandy beach. The animal has long siphons which are united about - one third of the way to their ends. Although this creature is - allied to the /Veneridae/, the degree of mantle fusion present is - much greater, leaving in this case only a fairly long slit through - which the foot may protrude. The shell is very dissimilar to that - of any of the /Veneridae/, and in many respects, judging from a - conventional standard, is a remarkable form. It is exceedingly - thin, is of a chalky texture, gapes widely posteriorly, and is - ornamented with transverse ribs, which are feeble upon the long - produced posterior portion of the shell, but strong in the anterior - part, where they are crossed by the coarse lines of growth, which - appear like vaulted scales upon the ribs. The color is a dull - white. There are two cardinals in each valve and no laterals. - Length one and a quarter to two and a half inches; height one half - to three quarters of an inch. This species passes its entire life - in the burrow it has made for itself in the clay. Its only motions - are made in climbing to the entrance of its burrow or in retreating - far out of sight within its depths. Its siphons are tipped with a - dark or drab color as a measure of protection from the predaceous - crabs which range about the mud surfaces near tidal marks, and are - always upon the lookout for succulent bits of flesh. - - [Illustration: /Petricola pholadiformis./] - - ^P. carditoides.^ A petricola of the Californian coast, very - similar in its habits to the east-coast form. It bores, however, - not only into clay, but also into soft rocks in order to effect a - permanent lodgment. Often this species occupies a hole which it has - discovered already existing; in this case its shell grows to fit - the surroundings. The hinge-teeth, and sculpturing are frequently - reduced and sometimes are quite obsolete; but the shell has the - chalky, thin texture that is characteristic of the genus. [pg453] - - There is another family of rock- and mud-boring bivalves which - superficially resemble the petricolas, but their anatomical - organization removes them to a little distance from the - /Petricolidae/. They are considered further on, under the name of - /Pholadidae/. - - -FAMILY ~CARDIIDAE~ - - -GENUS ^Cardium^ - -This is another important family of the /Pelecypoda/, which, with -the /Veneridae/, the /Mactridae/, and the /Tellinidae/, is entitled to -distinction on account of its high organization, its high type of -shell, its universal geographical distribution, and its great beauty. -The dominant genus is /Cardium/--a name given on account of the fact -that the shell is shaped like a heart. The animal has a very long, -recurved, and surprisingly strong foot. The mantle-edges are quite -freely open to the siphonal region and are highly papillate and -waved. The siphons are usually very short, but have wide exterior -openings and are also strongly papillate about their margins. The -gills are obliquely situated, and seem to be thicker and heavier -than is usual in pelecypods; they are much folded, the outer lamella -being the smaller. With such a pointed foot and such short siphons -/Cardium/ is obviously not a deep-burrowing genus; but it does -partially bury itself in soft semi-liquid sand. Its progression is -effected by leaps which it is enabled to make by reaching far out -with its foot, then suddenly twisting to one side and throwing the -shell several inches. The shell is ventricose, is closed or gapes -slightly posteriorly, and has prominent subcentral umbones and an -external ligament. The sculpture-scheme of /Cardium/ (if the shell -is not perfectly smooth) is one of radiating ribs or ridges, which, -being regular, form a perfect crenulation of the ventral margin. -There are two cardinal teeth in the center, and one lateral tooth -upon both the anterior and the posterior side: the latter are -situated at some little distance from the beaks. - - ^C. magnum.^ The largest and finest "cockle" of the east coast of - the United States. It is, indeed, one of the finest cockles in the - world. The almost perfect heart-shape is striking. The posterior - side is somewhat flatly depressed. The thirty-three to thirty-seven - regularly disposed, broad, radiating ribs; the regularly crenulated - margins; the yellowish-brown color garnished with transverse rows - of chestnut or [pg454] purple lines or spots; the brownish-purple - posterior area--all combine to make this large /Cardium/ a - beautiful species. Its length is four inches; height five and a - quarter inches. It is a very abundant species on the open Florida - beaches, where it is often left exposed and alive at very low - tides. (Plate LXXXIV.) - - ^C. isocardia.^ This also is a Floridian species, of elongated - heart-shape and with radiating ribs. It is not more than half - as large as the last-described species. The ribs are decorated - with erect vaulting scales which are exaggerated portions - of growth-lines. The beaks are smaller in proportion than - in /C. magnum/. The shell is brown to straw-color, stained - with purplish-brown without, and has a bright salmon-red or - purplish-pink interior. The margins are deeply crenulated. The - teeth are arranged as in the last-described species. It is very - common on the beaches of western Florida. (Plate LXXXIV.) - - ^C. serratum^, ^C. laevigatum^. These two species have a perfectly - smooth surface, and inflated, globose, heart-shaped shells, and - are of a creamy-white color, suffused with a yellowish, golden - tint which suggests the color of butter. Some forms are shiny, and - citron-yellow and pinkish toward the margins, whence the name of - "peach-shell." Height one to two inches. Not uncommon upon Florida - beaches. (Plate LXXXIV.) - - ^C. mortoni.^ Another of the smooth forms of /Cardium/ (placed in - the subgenus /Laevicardium/). It occurs in Florida and also extends - up the coast to Cape Cod, being very abundant in Long Island Sound. - In the neighborhood of Martha's Vineyard and along the north shore - of Long Island this very pretty little species has been reported as - occurring in soft ground even above low-tide mark, near the mouths - of creeks. It is enough to say of it that it is a smaller edition - of /C. laevigatum/ and may be further distinguished by a purple - blotch on the posterior margin, just within the valves, the general - color within being bright yellow. In young specimens, zigzag lines - of dark fawn-color upon the pale-yellowish background of the smooth - exterior surface of the shells are a noticeable feature. The - largest specimens measure an inch in length and nearly the same in - height. The long cirri upon the siphons are striking. - - [Illustration: /Cardium mortoni/, showing extended animal.] - - ^C. substriatum.^ A cockle of this inflated, smooth type, which - strongly resembles the east-coast form, found upon the Pacific - coast. The name indicates that it is not altogether smooth, a - fact only revealed, however, by a magnifying-glass. It is about - one half of an inch in length, and of a light drab-color, spotted - and sometimes radially lined with yellowish-brown. Professor Keep - likens this species in both shape and color to a sparrow's egg. - (Plate LXXXIV.) - - [Illustration: PLATE LXXXIV. 1, Cardium magnum, much reduced. 2, - Cardium isocardia. 3, Cardium laevigatum. 4, Cardium substriatum, - enlarged. 5, Cardium corbis (young specimen). 6, Glycimeris - generosa.] - - ^C. elatum.^ A veritable giant among the cardiums. It is found on - the southern Californian coast, though rarely north of the Mexican - border. It is of the smooth, glossy type belonging to the subgenus - /Laevicardium/. It attains a diameter of six inches, and is of a - creamy-yellow appearance. - - ^C. corbis^, ^C. quadrigenarium^. These two Californian cockles - are of the ribbed type displayed in the eastern /C. magnum/ and - /C. isocardia/. /C. corbis/ is found in the northern Californian - and Puget Sound region, [pg455] and /C. quadrigenarium/ on - the southern shores of California. The former is a full, round, - heart-shaped shell with about thirty somewhat scaly ribs. The edge - of the shell is deeply toothed; the color light brownish; the - diameter from two to three inches. It preserves all the features - of the genus as regards both shell and anatomical characters. The - other species, /C. quadrigenarium/, very strongly resembles /C. - magnum/ in size and shape. It lacks the flattened area on the - posterior portion of the shell which is characteristic of the - east-coast species, and its uniform brownish-white coloration is - less striking. It has about forty regularly spaced, radiating ribs, - which are smooth upon the umbonal region, but elsewhere are armed - with spiny processes. Diameter about six inches. (Plate LXXXIV.) - - [Illustration: /Cardium islandicum./] - - [Illustration: /Cardium pinnulatum./] - - ^C. islandicum^, ^C. pinnulatum^. Both of these are cold-water - species and occur along the New England coast. The former has - a shell which varies from one half of an inch to two inches in - length, and has from thirty-six to thirty-eight sharp, three-sided, - radiating ribs, the furrows between them being rounded and wrinkled - by growth-lines. A yellowish-brown epidermis covers the shell and - bristles into a sort of fringe upon the sharp edges of the ribs. - /C. islandicum/ cannot be said to be a very common species in New - England, although collectors have so reported it. Specimens from - Massachusetts are not as large as those of more northern habitat. - It does not occur south of Cape Cod. /C. pinnulatum/ is one of the - "small fry" among the cockles. Its largest diameter is less than - one half of an inch; but what it lacks in size it seems to endeavor - to make up in abundance, for it is scattered everywhere along the - coast from New York northward. Specimens can nearly always be found - in the stomachs of fishes, which, by the way, form an excellent - hunting-ground for rare species of mollusks of small size. There - are twenty-six slightly rounded ribs, with deep linear grooves - between them. Upon the ribs, especially in the posterior portion - of the shell, are arched scales, folded so as to appear like blunt - spines. The species may easily be distinguished from the young of - /C. islandicum/ by the smaller number of ribs. The animal, /C. - pinnulatum/, is said to be exceedingly lively and able to make - rapid progress over gravelly bottom by executing sudden leaps. - It has a long, recurved, very strong foot, and its movements are - effected as described above. It is abundant at Bar Harbor. [pg456] - - - -FAMILY ~MYIDAE~ - - -GENUS ^Mya^ - -In this family we encounter, rather suddenly, some new features not -heretofore seen in the pelecypod structure. In the first place, -the siphons are enormously large, are united, and are surrounded -by a leathery epidermis. The mantle-edges are fused together along -the entire ventral margin, except for a small slit through which -the foot may project. Although the animal may withdraw the long -siphons into its shell, yet they remain to a certain extent exposed, -for the valves gape widely posteriorly, and only slightly less -so anteriorly. In the economy of these forms the shell seems to -play a less important part than it does in the /Veneridae/, in the -/Tellinidae/, and generally in those families whose shells are strong -and, closing firmly, afford the animal within a real protection. The -shell of /Mya/ (the principal genus) is thin, white, and of a softer -chalky texture; it gapes widely "fore and aft," and has a loosely -constructed hinge apparatus, consisting of an erect projecting tooth, -which fits into a pit in the opposite valve. - -[Illustration: /Mya arenaria./] - - ^M. arenaria.^ This is the common "soft-shell clam" of New England. - Its range is from Cape Cod to Greenland and Great Britain. Upon - the Maine coast it is very extensively gathered and sold to the - Banks fishermen for bait. Its use as food for man is probably not - very great, yet it is always to be seen on sale in the markets of - New England coast towns. It cannot compare in flavor with /Venus - mercenaria/, the "hard-shell clam" south of Cape Cod. /M. arenaria/ - lives between tides in muddy, sandy, pebbly, or even rocky ground, - where it can find material in which it can burrow and hide itself. - It lies just below the surface, with its siphons projected into - the water. When the water recedes, /Mya/ draws in its siphons - and awaits the return of the tide, every now and then [pg457] - ejecting a jet of water into the air. The shells vary considerably - in size and thickness of valves. Large specimens are three and a - half inches long and two inches high. Our forefathers were not - always well posted upon the habits of mollusks, even though they - may have relished them in chowders and believed their flesh to - possess valuable curative properties. John Winthrop, in 1634, gave - a list of useful American animals, in which he remarked: "Clam, - white; their broth is most excellent in all intermitting fevers, - consumption, etc. These clams feed only on sand." What marvelous - digestive powers! - -[Illustration: /Mya arenaria/, showing extended animal.] - - -FAMILY ~SOLENIDAE~ - -[Illustration: /Ensis directus/, showing extended animal: 1, foot; 2, -siphons; 3, papillae, enlarged.] - -In this family are included the long, slender bivalves commonly -known as "razor-shells." Every one who has been to the sea-shore has -become familiar with these odd-looking mollusks, for their valves -are always to be found upon every beach. Their station is upon sandy -flats or bars more or less exposed at low tide. They burrow into -the sand perpendicularly to a depth of two or three feet, remaining -hidden most of the time. Occasionally a colony of them will be seen, -each one projecting slightly from his burrow. If approached most -cautiously some of them may be captured, but if the sand is jarred -they all take fright and disappear in an instant. It is no easy -matter to capture a "razor" when once he has taken warning, for he -will dig down into the sand about as fast as one can follow with a -spade. A good way to catch one is to approach his burrow carefully, -and then plunge a spade obliquely down below him, thereby [pg458] -cutting off his retreat. So tenaciously will they cling to the sand -by expanding the muscular foot that the shell may be pulled entirely -off the body before they will let go. - - -GENUS ^Ensis^ - - ^E. directus^ (^Solen ensis^, ^Ensis americanus^). The common - species upon the New England and Jersey coasts. The foot is long, - and protrudes from one end of the long shell; it is also very - strong, and capable of change at will into almost any form, from a - pointed bulb to a flat disk. The siphons, which project from the - opposite end of the shell, are short and are not united. The gills - are long. The juxtaposition of these organs is at first confusing, - because the greatly elongated form of the shell and the habits of - the animal in burrowing vertically into the sand have caused the - foot to be pushed farther away from the posterior portion of the - shell and to protrude in a direction just opposite to the siphons. - The shells are bent or slightly curved; they gape at both ends; and - they are fitted with very small interlocking teeth at the upper - corner of the posterior end. The color is white, but a yellowish or - greenish glossy epidermis covers the entire test. Length about six - inches. The manner in which the animal makes its rapid descent into - the sand is very interesting. First extending the foot lengthwise - into a point, it plunges it into the sand; then, by forcing water - into the organ it expands it, thus pushing away the sand on all - sides; and still further expanding the foot at the end into a disk, - it secures an anchorage which enables it to draw down its shell. By - quick repetition of this process /Ensis/ can get out of sight in a - remarkably sudden manner. - -[Illustration: /Ensis directus./] - - -GENUS ^Solen^ - - ^S. viridis.^ A smaller species, about two inches in length, and - with a nearly straight light-green shell. It is often abundant from - New Jersey southward. - - ^S. sicarius.^ The common Californian species of Northern range. It - is only about two inches long, and is rounded anteriorly, but is - chopped off squarely behind. It is slightly curved and white, and - has a glossy brown epidermis. - - ^S. rosaceus.^ Another species of Southern range, very similar - in form to the last, but straighter and rosy-white in color. The - epidermis is glossy brown. Length two inches. [pg459] - - -GENUS ^Tagelus^ - - ^T. gibbus.^ The extended range and shore station of this - exceedingly abundant species will cause it to be among the first - accessions to the cabinet of the collector south of Cape Cod. It - burrows deep in sand and mud, leaving two small openings to the - hole for the accommodation of its two excessively long siphons. - As in /Solen/ and /Ensis/, the foot is large and muscular, - tongue-shaped, and capable of remarkable change of form and great - freedom of movement. The long white siphons, separated from the - base and each provided with orange-colored eyes (or, rather, a - rudimentary sort of visual organs), are the most important feature. - The apex of the hinge is not, as in /Solen/ and /Ensis/, at the - end of the shell, but is more conventionally placed near the - middle; the cardinal teeth are very small, two upon each valve - and interlocking; a flat, oblong, callous process serves as a - fossette. The dorsal and ventral margins are parallel, and gape - at both ends; the shell is white, and is covered with a dense - yellowish epidermis, which, passing the ventral margin, appears to - become continuous with the thickened mantle-edge. There is no other - species north of Hatteras with which this could be confounded. - The double entrance to the burrow, which may be discovered about - low-tide mark, is unique. /T. gibbus/ is a good species to examine - for the crystalline stylet in the digestive tract. - -[Illustration: /Tagelus gibbus/, showing extended animal.] - -[Illustration: /Tagelus gibbus./] - - -FAMILY ~GLYCIMERIDAE~ - - -GENUS ^Glycimeris^ - - ^G. generosa.^ A large shell of the Pacific coast, occurring - most abundantly in Puget Sound waters, where it frequents muddy - shallows. It is a remarkable pelecypod in respect to its siphons - and the degree of mantle fusion. The appearance of the animal - is that of a huge pair of [pg460] united siphons, protected - laterally at their larger end by two white, widely gaping valves. - The very small pedal opening in the line or mantle juncture - indicates a very small foot. (Plate LXXXIV.) - - -FAMILY ~PHOLADIDAE~ - -There is a striking resemblance between the shells of this -rock-boring family and those of the petricolas--a resemblance which -consists principally in the texture of the shell and the tendency -to different types of sculpturing upon the posterior and anterior -surfaces of the valves. - - -GENUS ^Pholas^ - -In /Pholas/ the anterior part of the hinge-margin is reflected back -over the umbones, and a long rib-like tooth springs from under the -umbonal region and curves out almost to the center of the valves. -The shell gapes "fore and aft," and is thin, white, very hard, and -brittle. The animal has a short, truncated foot and a small orifice -in the mantle through which the foot may be projected. The siphons -are long and are united almost to their ends. Dorsally, an exposed -portion of the animal is protected by accessory calcareous plates. -The habits of /Pholas/ are very interesting. It is found in holes -gouged out of solid rock or out of pieces of wood; sometimes, like -/Petricola/, it may be found excavating in hard clay. As the anterior -end of a /Pholas/ shell is the larger in diameter, and is the end -which is most deeply buried in the rock (the opening of the burrow -being comparatively small), there was some mystery as to the way -in which the creature manages to get inside its rocky dwelling. -Observations in aquaria have shown that the young /Pholas/ begins his -process of home-building very early in life. The wearing away of the -stone is effected by constantly turning the shell around, scraping -with the anterior edges of the valves. A lodging-place having been -secured, /Pholas/ is obliged to work constantly to enlarge his burrow -for the accommodation of his growing shell. The long siphons may -project from the hole and draw in food and breath, but the animal is -a prisoner for life. When /Pholas/ has withdrawn his long siphons -he is reasonably secure from his enemies, but [pg461] nevertheless -thousands of them are destroyed by predatory starfishes, who know -how to get at their victims. The restless crustaceans, ever on the -outlook for a meal, often nip the siphons of the rock-dwellers, and -a kind of worm sometimes attacks them, and, destroying the animal, -proceeds to occupy the empty shell and burrow. - - ^P. costata.^ This species has a wide geographical range, being - found from Cape Cod to South America, but it is not abundant north - of Hatteras. In Florida it burrows deep in sand as well as in wood - or rock. On account of its white color and suggestive shape and - sculpture, it has received the popular name of "angel's-wings." It - grows to a length of seven or eight inches. - - [Illustration: /Pholas costata./] - - ^P. truncata.^ This has much the same range as the last, but is - more commonly to be found in New England waters. It also burrows - in any hard substance, or in mud above low-water mark. It is - especially common in peat-banks. - - [Illustration: /Pholas truncata./] - - ^P. californica.^ A Californian /Pholas/. The shell is about three - inches in length, and resembles in all features and habits the - /Pholas/ of the east coast. Differences in the shell indicate that - it is a distinct species. - - -GENUS ^Zirphaea^ - - ^Z. crispata.^ A species of Northern range, occurring but sparingly - in New England, in hard clay or rocky burrows. It may be identified - at once by the furrow which passes from the beaks across the valves - to the lower edges of the shell and divides the surface of the - valve into two areas. The anterior area is decorated with radiating - toothed ribs; the posterior area is smooth. This conchological - feature of the genus is very [pg462] curious; it may be observed - also in several deep-sea genera and in certain extinct fossil - forms. The length of this shell is about two inches. This species - also occurs in California, where its favorite station is in hard - tenacious clay. Length two to four inches. - -[Illustration: /Zirphaea crispata./] - - -FAMILY ~TEREDINIDAE~ - - -GENUS ^Teredo^ - - ^T. navalis.^ This species is worm-like in form, but it has a small - bivalve shell at the larger end, and near the anterior extremity - two calcareous appendages called pallets, beyond which extend two - siphons. Along the surface of the mantle is secreted a continuous - shelly tube which lines the burrow. This mollusk, commonly called - the "ship-worm," is exceedingly destructive, perforating with its - burrows submerged timber and soon rendering it useless. Various - means are taken to protect ships, the piles of wharves, buoys, and - the like, against its ravages; copper sheathing, large-headed nails - driven close together into the wood, verdigris paint, and so on, - being used with more or less effect. Vast numbers of these animals - enter the wood and burrow in various directions, but they never - interfere with one another, a thin partition of wood always being - left between adjacent burrows. How they effect the burrowing is - not determined, but it is supposed to be by means of the pallets. - /Teredo/ does not, like the boring isopod /Limnoria lignorum/, feed - upon the wood. Its food consists of microscopic organisms which - are taken in through the incurrent siphon. In temperate waters /T. - navalis/ grows sometimes to the length of six inches; in tropical - waters it attains the length of two feet. - - [Illustration: /Teredo navalis/, in a piece of timber: /P/, - pallets; /SS/, siphons; /T/, tube; /V/, valve of shell.] - - There are three other species of /Teredo/ and one of the genus - /Xylotrya/ on our Northern shores; /T. navalis/ is, however, the - most common and most destructive. In Southern waters there are many - other forms of these boring mollusks. [pg463] - - -FAMILY ~PANDORIDAE~ - - -GENUS ^Pandora^ - -[Illustration: /Pandora trilineata./] - - ^P. trilineata.^ A little New England shell, remarkable on account - of its extreme flatness. When looking at this shell before opening - it, one naturally wonders where the animal finds room to exist - between two such disk-like valves. The animal is very thin, with - largely united mantle-edges, widely separated feeble adductor - muscles, and a fairly large tongue-shaped foot. The shell is - nacreous, rounded anteriorly, and produced posteriorly into a sort - of upturned tip which gapes to accommodate two little siphons. The - dorsal hinge-margin is excavated and curved. Length about one inch. - It is abundant at Cape Cod, in sandy stations, on oyster-beds, and - is found from Maine to Florida. [pg464] - - -TABLE SHOWING THE CLASSIFICATION OF THE CEPHALOPODS DESCRIBED IN THIS -CHAPTER - - CLASS =CEPHALOPODA= - - Orders Genera Species - - Subclass =Tetrabranchiata= - - ^Nautilus^ - - Subclass =Dibranchiata= - - ~OCTOPODA~ ^Octopus^ - ^Argonauta^ ^A. argo^ - - ~DECAPODA~ ^Spirula^ - ^Ommastrephes^ ^O. illecebrosus^ - ^Sepia^ - ^Loligo^ ^L. Pealei^ - ^L. brevis^ - - -CLASS =CEPHALOPODA= - -The /Cephalopoda/ form a singularly isolated group, and are so -superior in organization and intelligence to all other mollusks -that it is difficult to believe that they are first cousins to the -lethargic gasteropod and the simply constructed bivalve. But the -class bears the stamp of its origin in a mantle, a radula, and a -disposition of internal organs and functions which, although highly -perfected, is essentially molluscan. - -Along the Atlantic coast of the United States, particularly in its -northern portion, occur several examples of cephalopods belonging to -the genera /Ommastrephes/ and /Loligo/, all the species of which are -referred to, in common parlance, as "squids." They frequent shallow -water, and are often to be found in weirs, darting about with rapid, -spasmodic movements, or perhaps lying motionless on the bottom. -The squids enter the weirs for the purpose of capturing the young -mackerel which are caught in these traps. The squid lies quietly upon -the bottom, which it simulates so closely in color as to be almost -invisible, and when [pg465] a school of fishes swims over it, darts -suddenly into the midst of it, seizes a fish with its sucker-bearing -arms, and kills it by the bite of its parrot-like beak or jaws. -Sometimes it happens that squids, while pursuing fish too near shore, -precipitate themselves upon the beach, where they flounder about, -ejecting water from their siphons, which pushes them only farther -away from the water, and squirting out "ink" from their ink-sacs in -a vain endeavor to hide themselves from view. On bright moonlight -nights squids often go ashore in vast numbers, and perish within a -few inches of their native element, which they seem to be unable -to regain. These creatures usually swim backward, and the theory -is that, dazzled by the bright light of the moon, they continue to -gaze at it while swimming, and if there happens to be a shore in the -direction of their movements, they suddenly find themselves beached. -The fishermen of Canada and New England take advantage of this habit -and capture great quantities of squids by placing bright lights in -the bows of their boats and then rowing toward shore, thus driving -the squids out of the water. The Banks fishermen use them as bait -for catching cod. The right claimed by American fishing-schooners to -purchase squids in Newfoundland has helped to keep alive the quarrel -between Canadian and American fishermen, which has vexed their -respective governments for many years. - -The range in size among the species of this class is very remarkable. -The little sepiolas are about an inch long; the squids of our -coasts vary in length from eight inches to one foot; and the giant -/Architeuthis/ of the North Atlantic measures, often, fifty feet -from the end of its arms to the tip of its tail. Such a creature, -with its long arms provided with suckers, its powerful jaws, and its -rapid, alert movements, is a formidable foe. These animals have been -the basis of many legends about sea-serpents and sea-monsters. A -gruesome story of an octopus is told by Victor Hugo in "The Toilers -of the Sea," where he gives a thrilling account of a man's encounter -with a devil-fish in a cave. One who has read this tale has a vivid -picture in his mind of the giant squid, and the danger of meeting -one of these many-armed foes. Victor Hugo's devil-fish, [pg466] -however, is an animal not true to nature, but a composite, having -the attributes of the polyp and of the octopus, and the name of a -large ray of Southern waters, a real fish, the /Cephaloptera/, known -in its localities as devil-fish. This monstrosity of the novelist's -imagination has, however, done more to acquaint the general public -with these interesting cephalopods than have the descriptions of -scientists. - -The giant squid, which is such a dangerous foe, has its own enemy in -the sperm-whale. The cachalot swims through the water with its lower -jaw hanging, the cephalopod grasps the jaw, and the whale then shuts -his capacious mouth upon it. Whalemen describe conflicts between -these enormous creatures, the whale always being the conqueror. -Sperm-whales killed by man often eject great quantities of the squids -in their death throes, showing this food to be almost their exclusive -diet. - -The name "cephalopod," meaning "feet around the head," is descriptive -in part of their anatomy. The head is usually marked off by a -neck-constriction, and it bears two highly organized eyes. The foot -is fused in part with the head above the eyes and around the mouth; -on the upper side it is divided into eight or ten long arm-like -processes, bearing suckers, which act as organs of prehension. The -under part of the foot forms a tube called the funnel. Through the -funnel the animal expels water from the mantle cavity, and thus -propels itself through the water. - -The mantle covers the body of the animal, and is a cup-shaped or -conical envelope, open only at the anterior end, through which -project the head and siphon or funnel. It is attached to the body by -a line on the dorsal side, the anterior margin being free and open, -but provided with an arrangement of cartilages by which it can be -hooked on to the siphon, thus completely closing the entrance to -the mantle cavity. The mantle is very muscular, and is constantly -expanding and contracting, taking water into the mantle cavity -through the mantle opening for respiratory purposes, or expelling -it through the siphon for propulsion; in the latter case the mantle -opening is closed at the moment of ejecting the water. When the -siphon is in its normal position [pg467] the animal swims backward; -but it can be turned back over the edge of the mantle, giving a -forward movement. - -The surface of the mantle is covered with pigment-cells -(/chromatophores/). There are sets of chromatophores containing -different colors. The cells are opened or closed at will by muscular -action of their walls. When open the cells seem to fuse together, -giving a solid color-surface, or spots of color as desired, in blue, -red, yellow, or brown; when closed they seem as specks on the almost -transparent tissues of the animal. Flashes of changing color follow -one another with great rapidity over the living animal. In swimming -it assumes the color of its surroundings. - -Another curious means of protection possessed by the dibranchiate -cephalopods is an ink-bag, the brown or black secretions of which are -ejected through the siphon, clouding the water when the animal wishes -to escape from danger. The ink taken from the ink-sac of /Sepia/ is -an article of commerce. - -Only /Nautilus/ and the female /Argonauta/ have the characteristic -external shell of mollusks. In all other forms the shell is internal -or is invested in the integument of the mantle. Of such is the -cuttlebone of commerce, which is a calcareous leaf-like body obtained -from /Sepia/, the cuttlefish. The common squid /Loligo/ has a horny -substance situated in the dorsal side of the mantle, called the pen. -/Spirula/ has a spiral internal shell divided into chambers. Vast -numbers of these shells are cast upon the beaches of the Pacific -Islands, and they have also been found on the shore of Nantucket. - -Cephalopods are separated into two subclasses. In the first, the -/Tetrabranchiata/, there are four branchiae, four nephridia, and four -auricles. They are without an ink-sac, and have the foot divided into -lobes bearing sheathed tentacles. /Nautilus/ is the only genus. - - -SUBCLASS =TETRABRANCHIATA= - - -GENUS ^Nautilus^ - -Probably the best-known cephalopod is /Nautilus/--the pearly-shelled, -chambered nautilus made immortal in the beautiful poem of Oliver -Wendell Holmes. The shell of /Nautilus/ is a flat spiral; the -interior is divided by septa forming a series of chambers; [pg468] -the septa are perforated, and through the opening runs a tube or -prolongation of the body, the siphuncle, which extends to the tip of -the shell. The chambers are filled with gas. The animal in the course -of its growth moves forward into a newly formed chamber and builds a -new septum, closing the cavity last occupied. /Nautilus/ lives among -the coral reefs of the southern Pacific. Its four or five species are -the remnants of a once very extensive race of cephalopods. The fossil -remains of many species of /Nautilus/, together with various other -genera of shell-bearing cephalopods, indicate that this group has -seen its best days. The dibranchiate genera, however, appear to have -reached their maximum at the present day. - - -SUBCLASS =DIBRANCHIATA= - -[Illustration: /Argonauta argo/, female removed from shell.] - -The second subclass, the /Dibranchiata/, is characterized by two -branchiae and two auricles. The main part of the foot is divided into -eight or ten long arms provided with numerous suckers arranged in -from one to four rows on the ventral side of the arms. They have -also an ink-sac. The /Dibranchiata/ are divided into two orders: the -/Octopoda/, which have eight arms, and comprise the /Octopus/ and -/Argonauta/; and the /Decapoda/, which have ten arms, and comprise -/Spirula/, /Ommastrephes/, /Sepia/, and /Loligo/. In these animals -two of the ten arms are longer than the others, and these tentacular -arms have suckers only on their broadened, club-like ends, they are -kept retracted within grooves, one on each side of the head, except -when needed for prehension. [pg469] - - -GENUS ^Argonauta^ - - ^A. argo.^ In this species, the paper-nautilus, the shell, which is - possessed only by the female, is not chambered. The animal rests in - the shell, but has no organic connection with it other than by the - membranous expansions at the extremities of the two dorsal arms, - which secrete it and hold it in place. The purpose of the shell is - to hold and protect the eggs. - -[Illustration: /Argonauta argo/, side view of shell.] - - -GENUS ^Loligo^ - - ^L. Pealei.^ In this species the body is cylindrical, tapers to a - point, and has a flat appendage in front. The fins are terminal, - half, or more than half, as long as the body, united in a point - posteriorly, and obtusely rounded on the outer angles. The head - is a little narrower than the mantle. There are eight sessile, - sub-triangular arms furnished with two series of suckers which - are hemispherical and stalked, and two long retractile tentacular - arms dilated at the extremities, bearing four rows of suckers. It - has a pen- or quill-shaped cartilaginous substance in the dorsal - integument of the mantle. Common from Cape Cod to South Carolina. - - ^L. brevis.^ A small short-bodied species, with short rounded - caudal fins. It is common from South Carolina to Florida, and - extends as far north as Delaware Bay. - -[Illustration: /Loligo Pealei/, young female; dorsal view.] - - -GENUS ^Ommastrephes^ - -[Illustration: /Ommastrephes illecebrosus/, young male; ventral view.] - - ^O. illecebrosus.^ A species similar to /L. Pealei/, but with - shorter fins. These are broad and pear-shaped, one third wider than - they are long, and usually reach less than one half the length of - the mantle. They are straight on the posterior end, and form nearly - a right angle, while the upper margins are rounded. The head is - as broad as the mantle. The arms are stout and taper to an acute - point. The tentacular arms are long when expanded. The species - is abundant from Cape Cod to Newfoundland, and is found as far - south as Newport, Rhode Island. This is the squid which is used so - extensively in the Banks fishery as bait. It [pg470] visits the - shores in large schools, presumably in pursuit of prey, and often - itself becomes the victim. It is a beautiful creature from its - varying colors, which are truly wonderful. It changes in a moment - from vivid red to deep blue, purple, orange, and so on, the colors - often passing over it in flashes as it swims along. [pg471] - - - - -VIII - -CHORDATA - - -TABLE SHOWING THE CLASSIFICATION OF THE CHORDATA DESCRIBED IN THIS -CHAPTER - - Phylum =CHORDATA= - - Class =UROCHORDA= or =TUNICATA= - - Order =LARVACEA= (/Free-swimming, pelagic; Tunicata having - caudal appendages/) - - Genera Species - - ^Appendicularia^ - - Order =THALIACEA= (/Free-swimming Tunicata, without caudal - appendages; single or in colonies; muscles of body-wall - arranged in complete or in interrupted ring-like bands/) - - Suborder =CYCLOMYARIA= (/Cask-shaped bodies with complete - rings of muscular bands; oral and atrial apertures at - opposite ends of the body/) - - ^Doliolum^ - - Suborder =HEMIMYARIA= (/Spindle-shaped bodies; muscular bands - in incomplete rings; oral and atrial apertures subterminal/) - - ^Salpa^ - - Suborder =PYROSOMATA= (/Hollow cylindrical colonies; zooeids - embedded in a gelatinous wall; oral apertures open on - the outer, atrial apertures open on the inner surface of - cylinder/) - - ^Pyrosoma^ - - Order =ASCIDIACEA= (/Mostly fixed Tunicata; single or in - colonies; tests of considerable thickness/) - - - Suborder =ASCIDIA SIMPLICES= (/Possess distinct tests; - usually permanently fixed/) - - Genera Species - - ^Molgula^ ^M. manhattensis^ - ^M. pellucida^ - ^M. arenata^ - ^Cynthia^ ^C. pyriformis^ - ^C. partita^ - ^C. carnea^ - ^Boltenia^ ^B. clavata^ - ^Ascidia^ ^A. amphora^ - ^A. callosa^ - - Suborder =ASCIDIA COMPOSITAE= (/Fixed colonies; the zooeids - embedded in a common gelatinous material; without separate - tests/) - - ^Botryllus^ ^B. gouldii^ - ^Amar[oe]cium^ ^A. pellucidum^ - -[pg474] - - - - -CHORDATA - - -CLASS =UROCHORDA= or =TUNICATA= - -The most conspicuous animals of this class are the ascidians, which -are common objects on rocky coasts. The /simple ascidians/ are -peculiar leathery, sac-shaped bodies which send out jets of water -when touched. This habit gives them the common name of "sea-squirts." -Some are highly colored, especially those of Southern waters; others -are somber, unattractive bodies, often growing in masses. The -/compound ascidians/ are gelatinous colonies, sometimes forming thin -incrustations, sometimes jelly-like masses, on seaweeds, shells, -etc. This class comprises also the beautiful /Salpa/, a genus of -free-swimming animals having transparent bodies encircled by rings of -muscular bands, and in one stage forming chains of attached organisms -which swim on the surface of the sea and of bays. - -The tunicates are by some authors classed with the vertebrate -animals because in the larval stage they have a notochord; this -disappears, however, in the adult form, and the animals are -considered degenerates. The tunicates are interesting to biologists -from the remarkable changes they undergo in their life-history, and -(in some genera) the marked phase of alternation of generation. One -of their curious anatomical features is the blood-vascular system. -The circulation is propelled by wave-like contractions of the heart, -which, after forcing the blood one way for a time, stops and reverses -the blood-current. The tunicates are widely distributed, and occur at -all depths. (Plate LXXXV.) [pg475] - - -GENUS ^Salpa^ - -[Illustration: /Salpa/ chain.] - -The animals of this genus are transparent, subcylindrical, smooth, -gelatinous bodies encircled by bands of white muscular fiber. They -strikingly exemplify alternation of generations. They occur in two -distinct conditions, one being solitary, the other consisting of -animals united in chains. The solitary individuals are about an inch -long, and have two long processes at the posterior end. These single -animals reproduce by budding, and form series of individuals in small -chains, the animals being arranged in two rows. The chains grow to -the length of a foot or more, and contain twenty to thirty pairs -of salpas. Each of these connected individuals produces in turn a -single egg, which becomes a single /Salpa/, and this again, like its -grandmother, reproduces by budding. Thus the animals are alike only -in alternate generations. The naturalist Chamisso, who discovered -the relationship between the two forms, expressed it as follows: a -/Salpa/ mother is not like its daughter or its mother, but resembles -its sister, its grandmother, and its granddaughter. The single zooeids -liberate many colonies during the summer, which grow rapidly, and in -the autumn the chains are exceedingly abundant. The /Salpa/ chains -swim about with a serpentine movement, and are beautiful, delicate -objects with their transparent bodies banded with white, tinged with -pink, and streaked with blue. - - -SIMPLE ASCIDIANS - -These are solitary and usually fixed; they are never free-swimming, -and when in colonies each animal has a distinct test. All the larger -ascidians, or sea-squirts, belong to this group. - - -GENUS ^Molgula^ - -Body more or less globular, membranous, attached or free; orifices on -very contractile tubes. - - ^M. manhattensis.^ Nearly globular when the tubes are contracted; - usually covered with bits of eel-grass, seaweeds, sand, etc.; - surface a [pg476] little rough; color olive-green. The animal is - often attached to rocks, more frequently to eel-grass and seaweeds, - and is sometimes so crowded as to form large clusters. Found from - Maine to North Carolina. - - ^M. pellucida.^ Body nearly globular, about an inch in diameter, - smooth, clean, and translucent, the intestine showing through the - test. The two tubes are large, swollen at the base, and divergent. - The animal lives free in the sand, and is found from Massachusetts - to North Carolina. - - ^M. arenata.^ Body somewhat compressed laterally; test thin and - covered completely with sand, which is closely adherent; about - three quarters of an inch in diameter; tubes short and wide apart. - Found on shelly and sandy bottoms of bays and sounds. - - -GENUS ^Cynthia^ - -The animal is attached, the body coriaceous, and the orifices -four-lobed. Frequently associated in groups, the individuals often -differing in color. - - ^C. pyriformis.^ Body globular, or oblong when extended; hard, - velvety, whitish surface, with pink cheeks; orifices on prominent - protuberances on the upper surface. It lives in clear, deep water - on rocks, and is sometimes found at low-water mark on the northern - New England coast. Commonly called the sea-peach. (Plate LXXXV.) - - ^C. partita.^ Body oblong; attached; test horny and wrinkled; - rusty-brown; apertures square, on prominent tubes marked with - triangular spots of white and purple; diameter one inch. Found on - the piles of wharves and on shelly bottoms in shallow water; also - on the under side of stones when they are much flattened. - - ^C. carnea.^ Test low and flat, with a thin margin; adherent by a - very broad base; orifices small, square, slightly prominent; red - or flesh-color. Found in deep water on stones and shells on the - northern New England coast. - - -GENUS ^Boltenia^ - -Body more or less globular, on a long stem; fixed; orifices on the -side. - - ^B. clavata.^ Body long, wrinkled, leathery, on a long stalk, - resembling the flower of lady's-slipper (/Cypripedium/); two - cross-shaped orifices wide apart on the side; yellowish in color; - attached to stones in deep water, but sometimes washed ashore in - storms. The stalks are often covered with polyzoans and hydroids. - (Plate LXXXV.) - -[Illustration: PLATE LXXXV. ASCIDIANS. 1, Ascidia callosa. 5, Cynthia -placenta. 2, Botryllus Schlosseri. 6, Glandula fibrosa. 3, Cynthia -pyriformis. 7, Cynthia condylomata. 4, The same, enlarged. 8, -Boltenia clavata. 9, Cynthia echinata.] - - -GENUS ^Ascidia^ - -Test gelatinous or cartilaginous; attached; it grows in bunches -under stones at low-water mark. Sometimes it is variously [pg477] -colored, but otherwise it is repulsive in aspect. The apertures are -wide apart; one orifice is eight-lobed, the other six-lobed. - - ^A. amphora.^ Form usually globular, but more or less irregular; - substance something like rubber. Found of all sizes adhering in - clusters to stones, shells, and piles, and usually covered with - marine growths. The color is grayish-brown. - - ^A. callosa.^ Body depressed, usually oval, but varying in shape; - thick, fleshy, translucent; surface uneven; apertures dark purple - and prominent. Found at low tide adhering to stones and shells. - (Plate LXXXV.) - - -COMPOUND ASCIDIANS - -Ascidians of this group form fixed colonies, and are embedded in -gelatinous material, the animals having a common test, but not being -united by any internal union. The colonies thus formed are flat and -incrusting, or are branched and lobed, or sometimes elevated on -stalks. The zooeids are in some cases dotted irregularly over the -entire surface, in others are in rows, or again are in groups. They -have various colors--purple, yellow, blue, gray, and green. They are -common on eel-grass, the piles of wharves, the bottoms of boats, and -so on. - - -GENUS ^Botryllus^ - - ^B. gouldii.^ This species forms thick, fleshy, translucent - incrustations, often several inches in length and a quarter of an - inch wide, over eel-grass, the piles of wharves, and other objects. - Sometimes, at the end of summer, small objects are completely - covered with the luxuriant growth of this compound ascidian. The - zooeids form circular or elliptical groups, often as many as fifteen - surrounding each orifice, looking like minute stars. The colonies - vary in color. Often on the same stem of eel-grass will be found - separate colonies varying in this respect. In some the ground-color - will be olive-green specked with white, while the zooeids are - purple, marked with other colors; again the arrangement is quite - different. - - -GENUS ^Amaraecium^ - - ^A. pellucidum.^ A massive compound ascidian, smooth, translucent, - and gelatinous, which forms large, hemispherical, complex, - irregular masses six inches or more in diameter. It is usually - covered by adhering sand. The mass consists of club-shaped lobes, - which rise from a common base. Each lobe contains a central orifice - around which long, slender zooeids, sometimes an inch long, are - grouped. These masses are so abundant in some places that they - cover the bottom for considerable spaces. They are found in deep - water from Cape Cod to North Carolina. [pg479] - - - - -INDEX - - -Heavy-faced type is used to indicate names of classes, orders, -genera, etc.; heavy-faced numerals to indicate the place where the -fullest description is given - - - A - - Abdomen, 243, =246=. - - Abductor muscles, =302=. - - Aboral, 202. - Surface, 201. - - Abyssal, =23=. - - Acalephs, =134=. - - =Acanthalithodes=, 240, =271=. - =A. hispidus=, 240, =271=. - - =Acephala=, 409. - - =Acetabularia=, 51, =57=. - =A. crenulata=, 51, =57=. - - =Acmaea=, 9, 309, 312. - =A. mitra=, 324, =357=. - =A. patina=, 324, =357=. - =A. testudinalis=, 41, 42, 324, 343, 348, =356=. - =A. testudinalis=, var. =alveus=, 324, =357=. - - =Acmaeidae=, 324, 356. - - Acontia, =145=. - - Acorn-shell, =254=. - - =Actiniaria=, 141, =142=, 143, 144. - - =Actinozoa=, 112, 115, 141, =142=. - - =Adamsia palliata=, 144, =267=. - - Adductor muscles, =302=, 413, 417. - - =AEolididae=, 324. - - =AEolis=, 41, 42, 309, 324, =354=. - =AE. papillosa=, 324, =354=. - - =AEquoreidae=, 116, =128=. - - =AEtea=, 188, =194=. - =AE. anguinea=, 188, /194/. - - =Agarum=, 36, 42, 63, 68, =69=. - - =Aglaophemia=, =127=. - =A. struthioides=, 116, =127=. - - =Ahnfeldtia=, 76, =82=. - =A. plicata=, 76, =82=. - - =Alaria=, 63, =69=. - =A. esculenta=, 41, 42, 63, =69=. - - =Albunaea=, 240, =269=. - =A. gibbesii=, 240, =269=. - - =Alcyonacea=, 141, =151=. - - =Alcyonaria=, 141, 142, =150=, 152. - - =Alcyonidium=, 189, 192, =197=. - A. hirsutum, 189, =197=. - =A. hispidum=, 189, =198=. - =A. parasiticum=, 189, =198=. - =A. ramosum=, 189, =197=. - - =Alcyonium=, 141, =151=. - =A. palmatum=, 141, =150=, 161. - - Aleutian province, =311=. - - =Algae=, =25=, =48=, 62, 76. - Botanical facts about, =25=. - - Alternation of generation, =120=, 121. - - =Amar[oe]cium=, 473, =477=. - =A. pellucidum=, 473, =477=. - - Ambulacra, 201, 202, =205=, 214, 218. - - Ambulacral groove, 205. - Ossicles, =205=. - Zones, 201, 202, =205=, 218, 229. - - American division, =24=. - - =Amphictenidae=, 162, =183=. - - =Amphineura=, 300, 316, 317, 320, =321=, 323. - - =Amphipoda=, 242, =289=. - - =Amphissa=, 312. - =A. corrugata=, 326, =389=. - - =Amphitrite=, 161, =182=. - =A. ornata=, 161, =182=. - - =Amphiura=, 213, =215=. - =A. squamata=, 213, =215=. - - Ampullae, 201, =205=, 206, 218. - - =Anadyomene=, 51, =57=. - =A. flabellata=, 51, =57=. - - Anatomy, 20. - Of higher Crustacea, =246=. - - Anemone Cave, =40=. - - Angel's-wings, 461. - - Animal-flowers, =142=. - - Animal life in its lowest forms, =21=. - - =Annelida=, 305. - - =Annulata=, 159, 161, 164, 170. - - =Anomia=, 405, =424=. - =A. aculeata=, 405, =425=. - =A. lampe=, 405, =425=. - =A. simplex=, 405, =424=. - - =Anomiidae=, 405, =424=. - - =Anomura=, 240, =264=. - - Antennae, 243, =246=, 258. - - Antennules, 243, =246=, 258. - - =Antheneidae=, 204, =209=. - - =Anthomedusae=, =116=. - - Aperture, =302=. - - Apex, 343. - - =Aphrodite=, 161, =174=. - =A. aculeata=, 161, =174=. - - =Aphroditidae=, 161, 172, =173=. - - =Aplacophora=, 300, 321, =323=. - - =Aplysella violacea=, 105. - - =Aplysia Wilcoxii=, =352=. - - =Aplysiidae=, 324. - - =Apoda=, 228, =233=. - - =Appendicularia=, 472. - - =Arabella=, 161, =179=. - =A. opalina=, 161, =179=. - - =Arbacia=, 217, =222=. - =A. punctulata=, 217, =222=. - - =Arbaciadae=, 217, 222. - - =Arca=, 310, 405, =425=. - =A. noae=, 405, =426=. - =A. pexata=, 405, =425=. - =A. ponderosa=, 405, =426=. - - =Arcachon=, 434. - - =Architeuthis=, 465. - - =Arcidae=, 405, =425=. - - Arctic province, =309=. - - =Arctica=, 406, =441=. - =A. islandica=, 406, =441=. - - =Arenicola=, 162, 172, =184=. - =A. marina=, 162, =184=. - - =Arenicolidae=, 162, =184=. - - =Argonauta=, 464, 467, 468. - =A. argo=, 464, =469=. - - Aristocratic genera, 313, 377, 398, 401. - - Aristotle's lantern, =203=. - - =Arthrocladia=, 62, =67=. - =A. villosa=, 62, =67=. - - =Arthropoda=, 238, =244=. - - =Arthrostraca=, 242, =289=. - - =Articulata=, 188. - - =Ascidia=, 473, =476=. - =A. amphora=, 473, =477=. - =A. callosa=, 473, =477=. - =A. compositae=, 473. - =A. simplices=, 473. - - =Ascidiacea=, 473. - - Ascidians, 8, 474. - Compound, 474, =477=. - Simple, 474, =475=. - - =Ascophyllum=, 63, =73=. - =A. nodosum=, 43, 63, 73. - - =Asperococcus=, 62, =66=. - =A. echinatus=, 62, =66=. - - =Astacoidae=, 240, =261=. - - =Astarte=, 309, 406, =440=. - =A. castanea=, 406, =441=. - =A. undata=, 406, =441=. - - =Astartidae=, 406, =440=. - - =Asterias=, 204, =212=. - =A. Forbesii=, 204, 207, =212=. - =A. gigantea=, 204, 207, =212=. - =A. ochracea=, 204, =212=. - =A. vulgaris=, 43, 204, 207, =212=. - - =Asteriidae=, 204, =212=. - - =Asterina=, 204, =210=. - =A. folium=, 204, =210=. - =A. miniata=, 204, =211=. - - =Asterinidae=, 204, =210=. - - =Asteroidea=, 200, 204, =205=. - - =Astraea=, 141, 146, 147, =148=. - - =Astrangia=, 141, =150=. - =A. danae=, 13, 141, =150=. - - =Astropecten=, 204, =209=. - =A. articularis=, 204, =209=. - - =Astropectinidae=, 204, =208=. - - =Astrophyton=, 213, =215=. - =A. Agassizii=, 213, =215=. - - =Astyris gausapata=, 326, =389=. - - =Asymmetrical=, 328. - - =Aurelia=, 133, =137=. - =A. flavidula=, 133, =137=. - - =Auricula=, =231=. - - =Auriculata=, 201. - - =Avicula=, 405, =431=. - =A. atlantica=, 405, 431. - - =Avicularia=, 190, =193=. - - =Aviculidae=, 405, =430=. - - - B - - =Balanus=, 239, 250, =254=. - =B. balanoides=, 239, =255=. - =B. crenatus=, =256=. - =B. eburneus=, 239, =255=. - =B. geniculatus=, 239, =256=. - =B. ovularis=, =255=. - =B. rugosus=, 239, =256=. - =B. tintinnabulum=, 239, =256=. - - =Bangia=, 78, =96=. - =B. fusco-purpurea=, 43, 78, =96=. - - =Bangiaceae=, 78, =96=. - - Barnacles, 8, 43, 245, =250=. - - Bathymetrical division, 23. - - =Bdelloura=, 160, =167=. - =B. Candida=, 160, =167=. - =B. rustica=, 160, =167=. - - Beach-flea, 245, =289=. - - Beak, 417. - - =Bela=, 309. - - Benthos, =23=. - - =Beroida=, 154, =157=. - - Bilateral symmetry, 20, 302, =320=, 321. - - Binomial nomenclature, 28. - - =Bipinnaria=, 201. - - Biramous, =243=, 257. - - =Bittium=, 326, =374=. - =B. nigrum=, 326. - - Bivalves, =306=, 307, 314, 315, 409. - Mud-boring, 452. - Rock-boring, 452, 460. - - Blastostyles, =120=. - - Blue crab, 275. - - Blue-green seaweeds, 47, 48, 49. - - Body-whorl, 304, =343=. - - =Bolina=, 154, =156=. - =B. alata=, 154, =156=. - =B. septentrionalis=, 154, =156=. - =B. vitrea=, 154, =156=. - - =Boltenia=, 473, =476=. - =B. clavata=, 473, =476=. - - =Bopyridae=, =292=. - - Boreal, 23. - - Boring amphipod, 290. - - Boring-sponges, 105. - - =Bostrychia=, 77, =89=. - =B. rivularis=, 77, =89=. - - Botanical facts about algae, =25=. - - =Botryllus=, 473, =477=. - =B. gouldii=, 473, =477=. - - =Bougainvillea=, =124=. - =B. superciliaris=, 116, =124=. - - Box-crab, =287=. - - =Brachyura=, 241, 258, =272=. - - Brain-corals, 146. - - Branchiae, 302, =319=, 329, 336, =413=. - Dermal, 208. - - =Branchiolaria=, 201. - - =Brissopsis=, 217, =227=. - =B. lyrifera=, 217, =227=. - - "Brit," =249=. - - Brittle-stars, 43, 200, =214=. - - Brown bodies, 190, =193=. - - =Bryopsis=, 51, =59=. - =B. plumosa=, 51, =59=. - - =Bryozoa=, =191=. - - Buccal mass, 302, =317=. - - =Buccinidae=, 327, =391=. - - =Buccinum=, 12, 309, 313, 327, 330, =392=. - =B. undatum=, 42, 44, 314, 327, 331, =392=. - - =Bucidium parasiticum=, 144. - - =Bugula=, 188, 192, 193, =195=. - =B. flabellata=, 188, =196=. - =B. Murrayana=, 188, =196=. - =B. turrita=, 43, 188, =195=. - - =Bulla=, 324, =351=. - =B. nebulosa=, 324, =351=. - =B. occidentalis=, 324, =351=. - =B. solitaria=, 324. - - =Bullidae=, =324=. - - Butterfly-shells, =323=. - - =Byssus=, =415=, 426, 432. - - - C - - =Caberea=, 188, =195=. - =C. Ellisii=, 188, =195=. - - Cake-urchins, 218, =224=. - - =Calappa=, 241, =287=. - =C. flamma=, 241, =287=. - - =Calappidae=, 241, =287=. - - =Calcarea=, 100, =104=, =106=. - - Calcareous hydroids, =129=. - Seaweeds, =31=, 147. - - Californian province, =312=. - - =Callinectes=, 241, =275=. - =C. hastatus=, 12, =275=. - =C. sapidus=, 241, 274, =275=. - - =Calliostoma=, 312, 325, =361=. - =C. annulatum=, 325, =361=. - =C. canaliculatum=, 325, =361=. - =C. costatum=, 325, =361=. - =C. jujubinum=, 325, =361=. - =C. occidentale=, 325, =361=. - - =Callista=, 311, 410. - =C. gigantea=, =450=. - =C. maculata=, =450=. - - =Callithamnion=, 15, 78, 79, =90=. - =C. americanum=, 78, =90=. - =C. Baileyi=, 78, =91=. - =C. byssoideum=, 78, =91=. - =C. floccosum=, 78, =91=. - =C. Pylaisaei=, 78, =91=. - =C. seirospermum=, 78, =91=. - - =Callophyllis=, 76, =82=. - =C. laciniata=, 76, =82=. - =C. variegata=, 76, =82=. - - =Calothrix=, 48, =49=. - - Cameo-cutting, =381=. - - Campanularians, 116, 121, =125=. - - Canal, 302. - Anterior, =344=. - Posterior, =344=. - System of sponge, 103. - - =Cancellaria=, 310, 327, =402=. - =C. reticulata=, 327, =402=. - - =Cancellariidae=, 327, =402=. - - =Cancellus=, =266=. - - =Cancer=, 241, =277=. - =C. antennarius=, 241, =280=. - =C. borealis=, 241, =277=. - =C. irroratus=, 241, =277=. - =C. magister=, 241, =278=. - =C. productus=, 241, =278=. - - =Cancroidae=, 241, =277=. - - =Caprella=, 8, 242, =291=. - =C. geometrica=, 242, =291=. - - =Capulidae=, 325, =369=. - - Carapace, 243, =246=. - - =Carcinides=, 241, =274=. - =C. maenas=, 241, =274=. - - =Carcinus maenas=, 41, =274=. - - =Cardiidae=, 407, =453=. - - =Cardita=, 406, =440=. - =C. borealis=, 406, =440=. - =C. floridana=, 406, =440=. - - =Carditidae=, 406, =439=. - - =Cardium=, 310, 311, 407, 410, 413, =453=. - =C. corbis=, 407, =454=. - =C. elatum=, 407, =454=. - =C. islandicum=, 407, =454=. - =C. isocardia=, 407, =454=. - =C. laevigatum=, 407, =454=. - =C. magnum=, 407, =453=. - =C. mortoni=, 407, =454=. - =C. pinnulatum=, 407, =454=. - =C. quadrigenarium=, 407, =454=. - =C. serratum=, 407, =454=. - =C. substriatum=, 407, =454=. - - Caribbean province, 310. - - Carinated, 302. - - Cartilage, =417=. - - Cartilaginous, 27. - - =Cassididae=, 326, 380. - - =Cassiopeia=, 133, =140=. - =C. frondosa=, 133, =140=. - - =Cassis=, 310, 326, =380=. - =C. cameo=, 326, =380=. - =C. inflata=, 326, =381=. - =C. Madagascarensis=, =381=. - =C. testiculus=, 326, =381=. - =C. tuberosa=, 326, =380=. - - =Caudina=, 228, =233=. - =C. arenata=, 228, =233=. - - =Caulerpa=, 51, 56, =59=. - =C. Mexicana=, 51, =60=. - =C. paspaloides=, Plate VIII. - =C. plumaris=, Plate VIII. - =C. plumosa=, 51. - =C. prolifera=, 51, =60=. - =C. Wurdemanii=, 51. - - =Caulerpaceae=, 51, =59=. - - =Cellepora=, 188, =197=. - =C. pumicosa=, 188, =197=. - =C. ramulosa=, 188, =197=. - =C. scabra=, 188, =197=. - - =Cellularia=, 188, =195=. - =C. ternata=, 188, =195=. - - =Cellularina=, 188. - - =Cenobita=, 240, =268=. - =C. diogenes=, 240, =268=. - - =Cenobitidae=, 240, =268=. - - Cephalic, 243, =246=. - - =Cephalopoda=, 301, 315, 320, 321, =464=. - - Cephalothorax, 243, =246=, 272. - - =Ceramieae=, 78, =90=. - - =Ceramium=, 27, 43, 78, =92=. - =C. diaphanum=, 78, =93=. - =C. fastigiatum=, 78, =93=. - =C. rubrum=, 78, =92=. - =C. rubrum, var. proliferum=, 78, =93=. - =C. rubrum, var. secundatum=, 78, =93=. - =C. strictum=, 78, =93=. - =C. tenuissimum=, 78, =93=. - =C. tenuissimum, var. patentissimum=, 78, =93=. - - =Cerata=, 353. - - =Cerebratulus=, 160, =170=. - =C. angulatus=, 160, =170=. - - =Cerianthus=, 144. - - =Cerithidea=, 326, =375=. - =C. sacrata=, 326, =375=. - =C. scalariformis=, 326, =375=. - - =Cerithiidae=, 326, =373=. - - =Cerithium=, 326, =374=. - =C. floridanum=, 326, =374=. - =C. minimum=, 326, =374=. - =C. muscarum=, 326, =374=. - - =Cerostoma=, 326, =385=, 387. - =C. foliatum=, 326, =385=. - =C. nuttallii=, 326, =385=. - - =Cestida=, 154, =157=. - - =Cestoda=, =160=. - - =Cestum=, 154, =157=. - =C. veneris=, 154, =157=. - - =Cetochilus=, 239, =249=. - - =Chaetae=, =173=. - - =Chaetangieae=, 76, =80=. - - =Chaetobranchus=, 161, =182=. - =C. sanguineus=, 161, =182=. - - =Chaetomorpha=, 51, =53=. - =C. aerea=, 51, =53=. - =C. linum=, 51, =54=. - =C. melagonium=, 51, =53=. - =C. picquotiana=, =54=. - =C. tortuosa=, =53=. - - =Chaetopoda=, 161, =171=. - - =Chalinopsilla=, 100, =107=. - =C. arbuscula=, 100, =107=. - =C. oculata=, 100, =107=. - - =Chamaedoris=, 51, =56=. - =C. annulata=, 51, =56=. - - =Champia=, 77, =85=. - =C. parvula=, 77, =85=. - - =Charybdaea=, 133, =137=. - =C. marsupialis=, 133, =137=. - - =Cheilostomata=, 188, 194. - - Chelae, 243, =258=. - - Cheliped, 243, =258=. - - =Chelura=, 242, =290=. - =C. terebrans=, 13, 242, 290. - - =Chicoreus rufus=, =382=. - - =Chione=, 406, =451=. - =C. fluctifraga=, 406, =451=. - =C. simillima=, 406, =451=. - =C. succincta=, 406, =451=. - - =Chiridotea=, 242, =294=. - =C. caeca=, 242, =294=. - =C. entomon=, 242, =294=. - - =Chiton=, 9, 309, =322=. - =C. albus=, =323=. - =C. apiculatus=, =323=. - =C. ruber=, 41, =323=. - =C. spinosus=, =322=. - - =Chitonidae=, 312, 322. - - =Chlorophyceae=, 28, 47, 51. - - =Chlorostoma=, 312, 325, =362=. - =C. brunneum=, 325, =362=. - =C. funebrale=, 325, =362=. - - Choanocytes, =102=. - - =Choanoflagellata=, 102. - - =Chondria=, 77, =90=. - =C. dasyphylla=, 77, =90=. - =C. striolata=, 77, =90=. - =C. tenuissima=, 77, =90=. - - =Chondrospongiae=, 100. - - =Chondrus=, 76, =80=. - =C. crispus=, 38, 76, =80=. - - =Chorda=, 63, 68, =69=. - =C. filum=, 63, =69=. - - =Chordaria=, 62, =67=. - =C. flagelliformis=, 43, 44, 62, =67=. - - =Chordariaceae=, 62, =67=. - - =Chordata=, 19, 472, =474=. - - =Chorus=, 312, 326, =388=. - =C. belcheri=, 326, =388=. - - Chromatophores, =467=. - - =Chrysodomus=, 12, 309, 313, 327, =392=. - =C. decemcostatus=, 327, =392=. - - =Chylocladia=, 77, =85=. - =C. articulata=, 77, =85=. - - =Cidaridae=, 217, =222=. - - =Cidaris=, 217, =222=. - =C. tribuloides=, 217, =222=. - - Ciliary flames, 164. - - Cinereous, 302. - - =Cirolana=, 242, =292=. - =C. concharum=, 242, =292=. - - =Cirratulidae=, 161, =181=. - - =Cirratulus=, 161, =181=. - =C. grandis=, 161, =181=. - - Cirri, =172=, 302. - - =Cirripedia=, 239, =250=. - - Cirripeds, 251. - - =Cistenides=, 162, =183=. - =C. Gouldii=, 162, =183=. - - =Cladocera=, =238=. - - =Cladophora=, 26, 51, =54=. - =C. arcta=, 51, =54=. - =C. gracilis=, 51, =54=. - =C. rupestris=, 51, =54=. - - =Cladostephus=, 62, =65=. - =C. verticillatus=, 62, =65=. - - Clam, 321, =448=. - Giant, 447. - Hard-shell, 448, 451, 456. - Little Neck, 410, 448. - Soft-shell, 456. - Worms, 176. - - Classification, =19=. - Of gasteropods, =348=. - Of mollusks, =320=. - - =Clava=, =122=. - =C. leptostyla=, 116, =122=. - - =Clibanarius=, 240, =267=. - =C. vittatus=, 240, =267=. - - =Cliona=, 100, =106=. - =C. sulphurea=, 100, 105, =106=. - - =Cloaca=, =229=. - - =Clymenella=, 162, =183=. - =C. torquata=, 162, =183=. - - =Clypeaster=, 217, =224=. - =C. ravenellii=, 217, =224=. - - =Clypeastroidea=, 217, =224=. - - =Clytia=, =126=. - =C. bicophora=, 116, =126=. - =C. poterium=, 116, =126=. - - Cockles, 453. - - =Codiaceae=, 51, =59=. - - =Codium=, 51, =59=. - =C. tomentosum=, 51, =59=. - - =C[oe]lenterata=, 111, 112, =113=. - - =C[oe]lopleurus=, 217, =222=. - =C. floridanus=, 217, =222=. - - C[oe]nosarc, 118. - - Coffee-shells, 379. - - Collecting, =6=. - And preserving seaweeds, =15=. - At Bar Harbor, =40=. - - =Columbella=, 326, =388=. - =C. avara=, 326, =389=. - =C. corrugata=, 326, =389=. - =C. gausapata=, 326, =389=. - =C. lunata=, 326, =389=. - =C. mercatoria=, 326, =388=. - =C. similis=, 326, =389=. - - =Columbellidae=, 326, =388=. - - Columella, 302, =344=. - - =Comatula=, 234, =235=. - - Comb-jellies, 112, 115, =155=. - - Communal life, 121. - - Conceptacles, =72=. - - Conchs, =377=. - - Conch-shell, =376=. - - Concrescent, =302=. - - =Confervaceae=, 26, 51, =53=. - - =Conidae=, 327, =401=. - - =Connostomae=, =133=. - - =Conus=, 313, 327, =401=. - =C. floridanus=, 327, =402=. - =C. gloria-maris=, 401. - =C. pealei=, 327, =402=. - - =Copepoda=, 239, =249=. - - =Corallina=, 29, 78, =96=. - =C. officinalis=, 41, 43, 78, =96=. - =C. rubrum=, 142, 146, =147=. - - Coralline Crags, =192=. - Zone, 30, =31=. - - =Corallineae=, 78, =95=. - - Corallite, =146=. - - Corallum, =146=. - - Corals, 112. - - Cordate, =302=. - - Cormophytes, 25. - - =Cornacuspongiae=, 100. - - =Coronula diadema=, 255. - - =Corymorpha pendula=, 116. - - =Coryne=, 116, =123=. - =C. mirabilis=, 116, 123. - - =Cosmocephala=, 160, =170=. - =C. ochracea=, 160, =170=. - - =Costae=, =302=. - - Cowry-shell, =377=. - - Crabe enrage, =274=. - - Crabs, 244, 247, =272=. - Blue, 275. - Box-, 287. - Fiddler-, 241, 282. - Ghost-, 282. - Green, 274. - Hermit-, 264. - Kelp-, 286. - Lady-, 276. - Mud-, 281. - Oyster-, 287. - Purple shore-, 281. - Red, 278. - Rock-, 277, 280. - Sand-, 11, 241, 276, 282. - Sheep-, 285. - Shore-, 281. - Spider-, 241, 284. - Stone-, 280. - Swimming, 241, 274. - Toad-, 285. - Walking, 241. - Yellow shore-, 281. - - =Crangon=, 240, =260=. - =C. franciscorum=, 240, =261=. - =C. vulgaris=, 240, =260=. - - Crawfish, 240, 259, =261=. - - Creeping Polyzoa, =193=. - - Crenulated, 302. - - =Crepidula=, 325, =369=. - =C. aculeata=, 325, =369=. - =C. adunca=, 370. - =C. fornicata=, 325, 369. - =C. navicelloides=, =370=. - =C. plana=, 325, =369=. - =C. rugosa=, =370=. - - =Cribrella=, 204, 207, =211=. - =C. sanguinolenta=, 204, =211=. - - Crimson Bluffs, 33. - - =Crinoidea=, 200, =234=. - - Crinoids, 202, 235. - Fossil, 235. - - =Crisia=, 188, =194=. - =C. eburnea=, 188, =194=. - - =Crossaster=, 204, =211=. - =C. papposus=, 204, =211=. - - Crucibulum, 325, =370=. - =C. spinosum=, 325, =370=. - =C. striatum=, 325, =370=. - - =Crustacea=, 238, =244=, 248, 257, 262. - - =Cryptochiton=, =323=. - =C. stelleri=, =323=. - - Cryptogams, 25. - - =Cryptolithodes=, 240, 271. - =C. sitchensis=, 240, 271. - - =Cryptonemiaceae=, 78, 94. - - =Cryptozonia=, 204, =211=. - - Crystalline stylet, 302, =341=. - - Ctenidia, 302. - - =Ctenodiscus=, 204, =208=. - =C. corniculatus=, 204, =208=. - - =Ctenophora=, 112, 115, 154, =155=. - - =Ctenostomata=, 189, =197=. - - =Cubomedusae=, 133, =137=. - - =Cucumaria crocea=, =231=. - =C. laevigata=, =231=. - - =Cumacea=, 242, =288=. - - =Cutleria=, 63, =71=. - =C. multifida=, 63, =71=. - - =Cutleriaceae=, 63, =71=. - - Cuttlefishes, 44, 315, =467=. - - =Cuvieria squamata=, =232=. - - Cuvierian organs, =231=. - - =Cyanea=, 133, 136, 138. - =C. arctica=, 44, 133, 138, =144=. - =C. fulva=, 133, =139=. - =C. versicolor=, 133, =139=. - - =Cyanophyceae=, 28, 48, =49=. - - =Cyclomyaria=, 472. - - =Cyclops=, 239, =249=, 250. - - =Cyclostomata=, 188, =193=. - - =Cydippida=, 154, 156. - - =Cymopolia=, 51, =57=. - =C. barbata=, 51, =57=. - - =Cynthia=, 473, =476=. - =C. carnea=, 473, =476=. - =C. partita=, 473, =476=. - =C. pyriformis=, 473, =476=. - - =Cypraea=, 326, 334, =377=. - =C. aurantia=, =377=. - =C. exanthema=, 326, =378=. - =C. moneta=, =378=. - =C. spadacea=, 326, =379=. - =C. spurca=, 326, =378=. - - =Cypraeidae=, 326, 377. - - =Cypridina=, =238=. - =C. islandica=, =441=. - - =Cyprinidae=, 406, =441=. - - =Cypris=, =238=. - - =Cyrena=, 311. - - =Cystoclonium=, 77, =83=. - =C. cirrhosa=, 77, =83=. - =C. purpurascens=, 77, =83=. - - =Cystoseira=, 63, =73=. - =C. expansa=, 63, =73=. - - =Cytherea=, 406, =450=. - =C. gigantea=, 406, =450=. - =C. maculata=, 406, =450=. - - - D - - Dactylopores, =129=. - - Dactylozooeids, =129=. - - =Daphnia=, =238=. - - =Dasya=, 77, 79, =89=. - =D. elegans=, 77, =89=. - =D. plumosa=, 77, =89=. - - =Dasycladaceae=, 51, =57=. - - =Dasycladus=, 51, =57=. - =D. occidentalis=, 51, =57=. - - =Decapoda=, 240, 257, 301, =468=. - - Decussated, =303=. - - =Delesseria=, 77, 79, 86. - =D. alata=, 77, 86. - =D. Leprieurii=, 77, 86. - =D. sinuosa=, 77, 86. - - =Delesserieae=, 77, =85=. - - =Dendronotidae=, 324. - - =Dendronotus=, 41, 42, 324, =353=. - =D. arborescens=, 324, =353=. - - =Dentalidae=, 327, =402=. - - =Dentalium=, 268, 327, 328, 404. - =D. dentale=, 327, 403. - =D. hexagonum=, 327, =403=. - =D. pretiosum=, 327, =403=. - - Dermal branchiae, =208=. - - =Desmacidonidae=, 100. - - =Desmarestia=, 15, 62, 66. - =D. aculeata=, 43, 62, 66. - =D. ligulata=, 62, 67. - =D. viridis=, 62, 66. - - =Desmarestiaceae=, 62, 66. - - Desmids, =33=. - - =Desmosticha=, 217, 221. - - Devil's pocket-books, 12. - - Dextral, 303, =345=. - - =Diadema=, 217, =222=. - =D. setosum=, 217, =222=. - - =Diadematidae=, 217, =222=. - - =Diastopora=, 188, =194=. - =D. patina=, 188, =194=. - - =Diastylis=, 242, =288=. - =D. quadrispinosus=, 242, =288=. - - =Diatocardia=, 300, 324, =356=. - - =Diatomaceae=, 38. - - Diatomaceous ooze, =21=. - - Diatoms, 21, =32=. - Green, 435. - - =Dibranchiata=, 301, 464, =468=. - - =Dictyosiphon=, 62, =67=. - =D. f[oe]niculaceus=, 62, =67=. - - =Dictyosiphonaceae=, 62, =67=. - - =Dictyota=, 63, =70=. - =D. dichotoma=, 63, =70=. - =D. fasciola=, 63, =70=. - - =Dictyotaceae=, 63, =70=. - - =Diopatra=, 10, 161, =178=. - =D. cuprea=, 161, =178=. - - =Diploria=, 141, 148. - =D. cerebriformis=, 141, =148=. - - =Discomedusae=, 133, =137=. - - Distribution of algae, =30=. - Of animal life in the sea, =23=. - - =Doliidae=, 326, =379=. - - =Doliolum=, 472. - - =Dolium=, 310, 326, =379=. - =D. galea=, 326, =379=. - =D. perdix=, 326, =379=. - - =Donacidae=, 406, =445=. - - =Donax=, 10, 406, =445=. - =D. californicus=, 406, =445=. - =D. variabilis=, 406, =445=. - - =Dorididae=, 324. - - =Doris=, 309, 324, =354=. - =D. bilamellata=, 324, =354=. - - =Dorocidaris=, 217, =222=. - =D. Blakei=, 217, =222=. - =D. papillota=, 217, =222=. - - Dorsal surface, 201, 202. - - =Dosinia=, 406, =450=. - =D. discus=, 406, =450=. - =D. elegans=, 406, =450=. - - Drill, =383=. - - =Dromia=, =105=. - - =Dromidae=, 240, =264=. - - Dulse, =38=. - - =Dumontieae=, 78, =94=. - - - E - - Ears, =247=, 435. - Of corn, 12. - - =Echidnocerus=, 240, =270=. - =E. cibarius=, 240, =270=. - =E. foriminatus=, 240, =271=. - - =Echinanthidae=, 217, =224=. - - =Echinanthus=, 217, =225=. - =E. rosaceus=, 217, =225=. - - =Echinarachnius=, 217, =225=. - =E. excentricus=, 217, =225=. - =E. parma=, 44, 217, =225=. - - =Echinaster=, 204, =211=. - =E. sentus=, 204, =211=. - - =Echinasteridae=, 204, =211=. - - =Echinidae=, 217, =223=. - - =Echinodermata=, 200, 202, 305. - - =Echinoidea=, 200, 203, 217, =218=, 221. - - =Echinometra=, 217, =223=. - =E. subangularis=, 217, =223=. - - =Echinometridae=, 217, =223=. - - =Echinus=, 217, =224=. - =E. gracilis=, 217, =224=. - - =Ectocarpaceae=, 28, 62, =64=. - - =Ectocarpus=, 28, 29, 62, =64=. - =E. Hooperi=, 29. - =E. littoralis=, 62, 64. - =E. siliculosus=, 62, =65=. - =E. tomentosus=, 62, =65=. - =E. viridis=, 62, =65=. - - Ectoderm, =101=, 118. - - =Ectoprocta=, 188, =193=. - - =Edwardsia=, =144=. - - Eel-grass, 12. - - Egg-capsules, =314=. - - Egg-cases, =11=, 12, 367. - - Eggs, 248, 314, 343, 414. - - =Elachista=, 62, =67=. - - =Elachistaceae=, =67=. - - =Elytra=, =173=. - - Embryology, =20=. - - =Enc[oe]liaceae=, 62, =65=. - - =Encope=, 217, =226=. - =E. michelini=, 217, =226=. - - Endoderm, =101=, 118. - - Endopodite, 243, =246=. - - Ensis, 310, 407, =458=. - =E. americanus=, =458=. - =E. directus=, 407, =458=. - - =Entalis=, 327. - =E. striolata=, 327, =403=. - - =Enteromorpha=, 26, 30, 51, =55=. - =E. clathrata=, 51, =55=. - =E. compressa=, 51, =55=. - =E. intestinalis=, 51, =55=. - =E. lanceolata=, 51, =56=. - - =Entomostraca=, 238, =249=. - - =Entoprocta=, 189, =198=. - - Ephyrula, =136=. - - =Epialtus=, 241, =286=. - =E. productus=, 241, =286=. - - Epidermis, 303, =345=, 347. - - Epimera, 243. - - Epipodite, 243. - - Epistoma, 243. - - =Epizoanthus americanus=, =267=. - - Equilateral, 418. - - Equivalve, 418. - - Erect Polyzoa, =193=. - - =Errantia=, 161, =173=, 180. - - =Escharella=, 188, =197=. - =E. variabilis=, 188, =197=. - - =Escharina=, 188. - - Escutcheon, 418. - - =Esperiopsis=, 100. - =E. quatsinoensis=, =100=. - - =Eucheuma=, 77, =84=. - =E. isiforme=, 77, =84=. - - =Eucope=, =125=. - =E. diaphana=, 116, =125=. - - =Eucratea=, 188, =195=. - - =E. chelata=, 188, =195=. - - =Eudendrium ramosum=, =116=, Plate XLI. - - =Eugorgia aurantica=, Plate XLVI. - - =Eulamellibranchiata=, 301, 406, 420, =438=. - - =Eunicea lugubris=, Plate XLVII. - - =Eunicidae=, 161, =178=. - - =Eupagurus kroyeri=, =267=. - =E. prideaux=, =267=. - =E. pubescens=, =267=. - - =Eupanopeus=, 241. - =E. herbstii=, 241, =281=. - - =Euphausia=, =239=, 247. - - =Euphyllopoda=, =238=. - - =Eupleura=, 326, =384=. - =E. caudata=, 326, =384=. - - =Euryalida=, 213, =215=. - - =Eurypanopeus=, 241. - =E. depressus=, 241, =281=. - - =Euspongia=, 100, =107=. - =E. officinalis=, 100, =107=. - =E. officinalis=, var. =adriatica=, 100, =108=. - =E. officinalis=, var. =dura=, 100, =108=. - =E. officinalis=, var. =mollissima=, 100, =108=. - =E. officinalis=, var. =rotunda=, 100, =108=. - - =Eusponginae=, =100=. - - =Euthora=, 77, =83=. - =E. cristata=, 77, =83=. - - Exopodite, 243, 246. - - Exoskeleton, 201, 203, =205=. - - Ex-umbrella, =120=. - - Eyes, 247, 322, =333=, 415, 416. - - - F - - Family, 20. - - =Fasciolaria=, 311, 327, 331, =397=. - =F. distans=, 327, =397=. - =F. gigantea=, 327, =397=. - =F. tulipa=, 327, =397=. - - =Fasciolariidae=, 327. - - Feather-stars, 200, =234=. - - =Fenja=, =144=. - - Fiddler-crabs, 12, 241, =282=. - - Filamentous plants, =26=. - - =Filibranchiata=, 301, 405, 420, =423=. - - Finger-pores, =129=. - - =Fissurella=, 324, =357=. - =F. alternata=, 324, =357=. - =F. aspersa=, =324=. - =F. barbadensis=, 324, =357=. - - =Fissurellidae=, 324, =357=. - - Flagellate Infusoria, =102=. - - Flatworms, =164=. - - =Florideae=, 28, =31=, 76. - - =Flustra=, 188, =196=. - =F. foliacea=, =192=. - =F. membranacea=, 188, =196=. - - =Flustrina=, 188. - - Foot, 303, 317, 320, 321, 328, =415=. - Gasteropod, =334=. - - =Foraminifera=, =21=, 22. - - Fossette, 303, 418. - - =Fovia=, 160, =167=. - =F. Warrenii=, 160, =167=. - - Free-swimming colonies, =130=. - - Frond, =26=. - - =Fucaceae=, 27, 63, =71=. - - =Fucus=, 15, 17, 30, 63, 64, =72=. - =F. ceranoides=, 63, =73=. - =F. furcatus=, 63, =73=. - =F. serratus=, 63, =73=. - =F. vesiculosus=, 38, 63, =72=. - - =Fulgur=, 10, 11, 310, 314, 327, 330, =394=. - =F. canaliculata=, 12, 327, =395=. - =F. carica=, 12, 327, =395=. - =F. perversa=, 327, =396=. - =F. pyrum=, 327, =396=. - - Functional siphon, 331. - - Fuscous, 303. - - Fusiform, =303=. - - - G - - =Gammarus=, 9, 43, 242, =290=. - =G. annulatus=, =290=. - =G. locusta=, 242, =290=. - =G. mucronatus=, =290=. - - =Gasteropoda=, 300, 320, 324, =328=, 335. - - Gastric mill, 243, =247=. - - Gastropores, 129. - - =Gelasimus minax=, =282=. - =G. pugilator=, =282=. - =G. pugnax=, =282=. - - Gelatinous, =27=. - - =Gelidieae=, 76, =80=. - - =Gelidium=, 76, =80=. - =G. corneum=, 76, =80=. - =G. Coulteri=, Plate XVII. - - Generic name, =28=. - - Genus, 20. - - Geographical distribution, =308=. - - =Gephyrea=, 171, 185. - - =Geryonopsidae=, 116, =128=. - - Ghost-crab, =282=. - - Giant crab of Japan, =244=. - - =Gigartina=, 28, 76, =81=. - =G. mamillosa=, 76, =81=. - =G. microphylla=, 76, =81=. - =G. radula=, 76, =81=. - =G. spinosa=, 76, =81=. - - =Gigartinaceae=, 28, 76, =80=. - - Gills, =247=, 329, =336=, =413=. - - Girdle, 322. - - Glass-rope sponge, =102=. - - =Globigerina=, =21=. - - Globigerina ooze, =21=. - - =Gloiosiphonia=, 78, =94=. - =G. capillaris=, 78, =94=. - - =Gloiosiphonieae=, 78, =94=. - - Glove sponge, =104=. - - =Glycera=, 161, =180=. - =G. americana=, 161, =180=. - =G. dibranchiata=, 161, =180=. - - =Glyceridae=, 161, =179=. - - =Glycimeridae=, 407, =459=. - - =Glycimeris=, 407, =459=. - =G. generosa=, 407, =459=. - - =Glyphis=, 324, =358=. - =G. aspersa=, 324, =358=. - - Gonads, 135, =341=. - - Gonangium, =118=. - - Gonophore, 118. - - Goose-barnacle, =252=. - - =Gorgonacea=, 141, =152=. - - =Gorgonia anceps=, Plate XLVI. - =G. flabellum=, Plate XLVII. - - =Gracilaria=, 77, =84=. - =G. lichenoides=, 39. - =G. multipartita=, 77, =84=. - =G. spinosa=, 39. - - =Grantia=, 100, =106=. - =G. ciliata=, 100, 105, =106=. - - =Grapsidae=, 241, =281=. - - Grass sponge, =104=. - - =Grateloupia=, 78, =94=. - =G. Cutleria=, 78, =94=. - - =Grateloupieae=, 78, =94=. - - Green glands, =246=. - - =Griffithsia=, 15, 29, 78, =91=. - =G. Bornetiana=, 78, =91=. - =G. corallina=, 29. - - =Grinnellia=, 29, 77, =86=. - =G. Americana=, 29, 77, =86=. - - =Gymnogongrus=, 76, =82=. - =G. Norvegicus=, 76, 82. - - =Gymnolaemata=, 188, =193=. - - - H - - =Halcyonoida=, 141, =150=. - - Halcyonoids, =142=. - - =Halichondria=, 100, =107=. - =H. panicea=, 100, =107=. - - =Halidrys=, 63, =73=. - =H. osmunda=, 63, =73=. - - =Halimeda=, 51, =58=. - =H. opuntia=, 51, =59=. - =H. tridens=, 51, =59=. - =H. tuna=, 51, =58=. - - =Haliotidae=, 324, =358=. - - =Haliotis=, 9, 312, 324, =358=. - =H. cracherodii=, 324, =359=. - =H. rufescens=, 324, =359=. - =H. splendens=, 324, =359=. - - =Haliseris=, 63, =71=. - =H. polypodioides=, 63, =71=. - - =Halosaccion=, 78, =95=. - =H. ramentaceum=, 78, =95=. - - =Halymenia=, 78, =94=. - =H. ligulata=, 78, =94=. - - =Haminea solitaria=, 324, =351=. - - =Harmothoe=, 161, =174=. - =H. imbricata=, 161, =174=. - - Heart, 416. - - Heart and vascular system, =341=. - - Heart-urchins, 218, =226=. - - =Heliaster=, 204, 205, =212=. - =H. multiradiata=, 204, =212=. - - =Heliasteridae=, 204, =212=. - - =Helipora=, 147. - - Helmet-shells, =380=. - - =Helminthocladieae=, 76, =79=. - - =Hemigrapsus=, 241, =281=. - =H. nudus=, 241, =281=. - =H. oregonensis=, 241, =281=. - - =Hemimyaria=, 472. - - Herbarium, 17. - - Hermit-crabs, 12, 258, 259, =264=, 362. - - =Heteroc[oe]la=, 100. - - =Heterograpsus nudus=, =281=. - =H. oregonensis=, =281=. - - =Heterorrhaphidae=, 100. - - =Hildenbrandtia=, 78, =95=. - =H. rosea=, 40, 78, =95=. - - =Himanthalia=, 63, =71=. - =H. lorea=, 63, =71=. - - =Hippa=, 10, 240, =268=. - =H. analoga=, 240, =269=. - =H. talpoida=, 10, 11, 240, =268=. - - =Hippasteria=, 204, =209=. - =H. phrygiana=, 204, =209=. - - =Hippidae=, 240, =268=. - - =Hippoconcha=, 240, =264=. - =H. arcuata=, 240, =264=. - - =Hippospongia=, 100, =108=. - =H. canaliculata=, 100, =108=. - =H. canaliculata=, var. =flabellum= 100, =109=. - =H. canaliculata=, var. =gossypina=, 100, =108=. - =H. equina=, 100, =108=. - =H. equina=, var. =agaricina=, =108=. - =H. equina=, var. =cerebriformis=, 100, =108=. - =H. equina=, var. =dura=, =108=. - =H. equina=, var. =elastica=, 100, =108=. - =H. equina=, var. =meandriformis=, 100, =108=. - - =Hircinia=, 100, =109=. - =H. campana=, 100, =109=. - - Histology, =20=. - - Holdfasts, 26. - - =Holocampa=, 141, =145=. - =H. producta=, 141, =145=. - - =Holothuria edulis=, =232=. - - Holothurians, 202, 203. - - =Holothuroidea=, 200, 228, =229=. - - =Homarus=, 240, =261=. - =H. americanus=, 240, =262=. - =H. capensis=, =261=. - =H. vulgaris=, =261=. - - =Homorrhaphidae=, 100. - - How to arrange a herbarium, =17=. - - =Hyas=, 241, 284, =285=. - =H. araneus=, 241, =285=. - =H. coarctatus=, 241, =285=. - =H. lyratus=, 241, =285=. - - =Hybocodon=, =124=. - =H. prolifer=, 116, =124=. - - =Hydractinia=, 116, =122=. - =H. polyclina=, 116, =122=, 266. - - =Hydrallmania falcata=, =127=. - - Hydranth, 118, 119. - - =Hydrocorallina=, 117, =129=. - - Hydroids, 22, 114, =119=. - - Hydrorhiza, 118. - - Hydrosoma, 118. - - Hydrotheca, 118. - - =Hydrozoa=, 112, 114, 116, =119=, 120. - - =Hypnea=, 77, =84=. - =H. musciformis=, 77, =84=. - - - I - - Ideal mollusk, =317=. - - =Idotea=, 242, =293=. - =I. irrorata=, =293=. - =I. marina=, 242, =293=. - =I. metallica=, 242, =294=. - =I. ochotensis=, 242, =294=. - =I. wosnesenskii=, 242, =294=. - - =Idyia=, 154, =157=. - =I. cyanthina=, 154, =158=. - =I. roseola=, 154, =157=. - - =Inarticulata=, 188. - - =Infusoria=, 21, 101. - - Interambulacral areas, 201, 202, 218. - - Introvert, 186. - - =Iridaea=, 76, =82=. - - =Isopoda=, 242, =291=. - - Isopods, 12. - - - J - - =Janthina=, 325, =364=. - =J. fragilis=, 325, =365=. - - =Janthinidae=, 325, =364=. - - =Jellyfishes=, 7, 44, 112, 115, 119, =134=. - - Jonah crab, =277=. - - - K - - Kelp, =38=. - - Kingdom, =19=. - - Kitchen-middens, 432. - - - L - - Labial palps, 416. - - =Labiosa canaliculata=, =447=. - - =Lacuna=, 309, 326, =373=. - =L. vincta=, 12, 44, 326, =373=. - - Lady-crab, =276=. - - =Lambrus=, 241, =286=. - =L. pourtalesii=, 241, =286=. - - =Lamellibranchiata=, 409. - - Lamelliform, 303. - - =Laminaria=, 43, 63, =70=. - =L. digitata=, 44, 63, =70=. - =L. longicruris=, 63, =70=. - =L. saccharina=, 63, =70=. - - =Laminariaceae=, 31, =35=, 38, 63, 64, 68. - - Laminarian zone, 30,=31=. - - Larva, 201. - - =Larvacea=, 472. - - =Laurencia=, 77, =89=. - =L. pinnatifida=, 77, =89=. - - Laver, =38=. - - =Leathesia=, 62, =68=. - =L. difformis=, 41, =68=. - =L. tuberiformis=, =68=. - - =Leda=, 309, 405, =422=. - =L. tenuisulcata=, 405, =422=. - - =Lepas=, 239, 250, =252=. - =L. anatifera=, 239, =253=. - =L. pectinata=, 239, =253=. - =L. striata=, 239, =253=. - - =Leptodora=, =238=. - - =Leptogorgia Agassizii=, Plate XLVII. - =L. rigida=, Plate XLVII. - - =Leptoliniae=, 116, =121=. - - =Leptomedusae=, =116=. - - =Leptoplana=, 160, =166=. - =L. folium=, 160, =166=. - - =Lessonia=, =36=, 63. - - =Leucosolenia=, 100, =106=. - =L. botryoides=, 100, =106=. - - =Liagora=, 76. - - =Libinia=, 241, =284=. - =L. dubia=, 241, =284=. - =L. emarginata=, 241, =284=. - - Ligament, 417. - - =Limnoria=, 242, =292=. - =L. lignorum=, 13, 242, 290, =292=. - - Limpets, 9. - - =Limulus=, 242, =294=. - =L. moluccanus=, =295=. - =L. polyphemus=, 242, =294=. - - =Linerges=, 133, =139=. - =L. mercurius=, 133, =139=. - - Lines of growth, =344=, 347. - - =Lineus marinus=, =167=. - =L. sanguineus=, =168=. - - Lingual ribbon, 303, =340=. - - Lip, inner, =344=. - Outer, =344=. - - Lithocysts, =135=. - - =Lithodes=, 240, =270=. - =L. maia=, 240, =270=. - - =Lithodidae=, 240, =270=. - - Littoral, =23=. - Species, 308. - Zone, =30=. - - =Littorina=, 9, 309, 311, 325, 338, =370=. - =L. angulifera=, 325, =372=. - =L. irrorata=, 325, =372=. - =L. litorea=, 8, 41, 42, 325, =371=. - =L. palliata=, 42, 325, =372=. - =L. planaxis=, 325, =373=. - =L. rudis=, 41, 42, 325, =371=. - =L. scutulata=, 325, =373=. - - =Littorinella minuta=, 12. - - =Littorinidae=, 325, 338, =370=. - - =Livona=, 325, 362. - =L. pica=, 268, 325, =362=. - - =Lizzia=, 120. - - =Lobata=, 154, =156=. - - Lobsters, 240, 247, 250, 258, 259, =261=. - - =Loligo=, 464, 467, 469. - =L. brevis=, 464, =469=. - =L. Pealei=, 464, =469=. - - =Lomentaria=, 77, =85=. - =L. Baileyana=, 77, =85=. - - Lophophore, 190, =193=. - - =Lophothuria=, 228. - =L. fabricii=, 228, =232=. - - =Loripes=, 406, =443=. - =L. edentula=, 406, =443=. - - =Lottia=, 324, =357=. - =L. gigantea=, 324, =357=. - - =Lovenia=, 217, =227=. - =L. cordiformis=, 217, =227=. - - =Loxorhynchus=, 241, =285=. - =L. crispatus=, 241, =285=. - - =Lucapina=, 324, =358=. - =L. crenulata=, 324, =358=. - - =Lucernaria=, 133, =136=. - =L. auricula=, 133, =136=. - - =Lucina=, 311, 406, =442=. - =L. californica=, 406, =443=. - =L. dentata=, 406, =443=. - =L. floridana=, 406, =442=. - =L. nuttallii=, 406, =443=. - =L. pennsylvanica=, 406, =442=. - =L. tigrina=, 406, =442=. - - =Lucinidae=, 406, =442=. - - =Luidia=, 204, =209=. - =L. alternata=, 204, =209=. - =L. clathrata=, 204, =209=. - =L. senegalensis=, 204, =209=. - - =Lumbriconereis=, 161, =179=. - =L. tenuis=, 161, =179=. - - =Lunatia=, 12, 309, 314, 325, =367=. - =L. heros=, 10, 12, 44, 325, =367=. - =L. lewisii=, 325, =368=. - =L. triseriata=, 325, =367=. - - Lunules, =224=, 303, 418. - - =Lyngbya=, 48. - =L. aestuarii=, =50=. - =L. ferruginea=, =50=. - =L. majuscula=, =50=. - - - M - - =Macoma=, 406, =444=. - =M. baltica=, 406, =445=. - =M. nasuta=, 406, =444=. - =M. proxima=, 406, =445=. - =M. secta=, 406, =444=. - =M. tenta=, 406, =445=. - - =Macrocystis=, =35=, 63. - =M. pyrifera=, 36, =70=. - - =Macrura=, 240, 258, =259=, 272. - - =Mactra=, 310, 406, 410, =446=. - =M. lateralis=, 406, =447=. - =M. ovalis=, 406, =447=. - =M. similis=, 406, =447=. - =M. solidissima=, 406, =446=. - - =Mactridae=, 406, =446=. - - Madreporic plate, 201, =203=, =206=, 218. - - =Maiidae=, 241, =284=. - - =Malacostraca=, 239, =257=. - - Mandibles, =246=, 258. - - Mantle, 303, =316=, 319, 328, 331, =410=. - - Mantle cavity, 303, 319, =336=. - - Mantle fusion, =412=. - - =Margarita=, 309, 325, =360=. - =M. cinerea=, 325, =360=. - =M. helicina=, 12, 44, 325, =360=. - =M. undulata=, 325, =360=. - - Margin, 417. - Anterior, 417. - Dorsal, 417. - Posterior, 417. - Ventral, 417. - - =Marginella=, 311, 327, =399=. - =M. apicina=, 327, =399=. - - =Marginellidae=, 327, =399=. - - Marine invertebrates, 97. - - Maxillae, 243, =246=, 258. - - Maxillipeds, 243, =246=, 258. - - =Meckelia=, 160, =169=. - =M. ingens=, 160, =169=. - =M. rosea=, 160, =169=. - - =Mediaster=, 204, =209=. - =M. aequalis=, 204, =209=. - - =Megalops=, =248=, 273. - - =Meleagrina margaritifera=, 313, 430, 431. - - =Melita nitida=, =290=. - - =Mellita=, 217, =225=. - =M. testudinata=, 217, =225=. - - =Melobesia=, 78, =96=. - - =Melongena=, 311, 327, =396=. - =M. corona=, 327, =396=. - - Membranaceous, 27. - - =Membranipora=, 188, 192, =196=. - =M. lineata=, 188, =196=. - =M. pilosa=, 43, 188, =196=. - =M. tenuis=, 188, =197=. - - =Menippe=, 241, =280=. - =M. mercenaria=, 241, =280=. - - =Meristomes=, 242, =294=. - - Mesoderm, =101=, 118. - - =Mesogl[oe]a=, 62, =68=. - =M. divaricata=, 62, =68=. - =M. virescens=, 62, =68=. - - =Metalia=, 217, =227=. - =M. pectoralis=, 217, =227=. - - Metameres, =243=. - - Metapodium, 376. - - =Metazoa=, 101. - - =Metridium marginatum=, 42. - - =Microciona=, 100, =107=. - =M. prolifera=, 100, =107=. - - =Microcladia=, 78, =93=. - =M. borealis=, 78, =93=. - =M. Coulteri=, 78, =93=. - - =Millepora=, =129=. - =M. alcicornis=, 117, =129=. - - =Mitra=, 313. - - =Mnemiopsis=, 154, =157=. - =M. Leidyii=, 154, =157=. - - =Modiola=, 309, 405, =426=. - =M. modiolus=, 405, =428=. - =M. nigra=, =429=. - =M. plicatula=, 405, =429=. - =M. recta=, 405, =429=. - =M. tulipa=, 405, =429=. - - =M[oe]ra levis=, =290=. - - =Moina=, =238=. - - =Moira=, 217, =226=. - =M. atropos=, 217, =226=. - - =Molgula=, 473, =475=. - =M. arenata=, 473, =476=. - =M. manhattensis=, 473, =475=. - =M. pellucida=, 473, =476=. - - =Mollia=, 188, =197=. - =M. hyalina=, 188, =197=. - - =Mollusca=, 300, =305=, 328. - - =Monoceras=, 312, 326, =387=. - =M. engonatum=, 326, =388=. - =M. lapilloides=, 326, =388=. - - Monomyarian, =303=, 430. - - =Monostroma=, 26, 51, =55=. - - =Monotocardia=, 300, 325, =364=. - - Morphology, 20. - - Moss-animals, =191=. - - Mother-of-pearl, 431. - - Moulting, =248=, 259, 263. - - Mounting seaweeds, =16=. - - Mouth, 329, =333=. - - Mud-crabs, 12. - - Muddy shores, =12=. - - Multivalve, 307. - - =Murex=, 326, 331, =382=. - =M. fulvescens=, =383=. - =M. pomum=, 326, =383=. - =M. rufus=, 326, =382=. - =M. tenuispina=, =343=, 347. - - =Muricea specifera=, Plate XLVI. - - =Muricidae=, 326, =381=. - - =Muricinae=, 326, =381=, 385. - - Muscles, =248=. - - Musical sands, 2. - - Mussel, great horse-, 428. - - Mussels, 43, 321, =426=. - - =Mya=, 309, 407, =456=. - =M. arenaria=, 3, 42, 44, 311, 407, =456=. - - =Mycedium fragile=, Plate XLV. - - =Myidae=, 407, =456=. - - =Myrionema=, 62, 68. - - =Mysis=, 239, =257=. - =M. sternolepsis=, 239, =257=. - - =Mytilidae=, 406, =426=. - - =Mytilus=, 41, 309, 406, =426=. - =M. californicus=, 405, =428=. - =M. edulis=, 42, 43, =287=, 405, 427, =428=. - =M. hamatus=, 405, =428=. - - - N - - Naming of plants, =28=. - - =Nanomia=, =130=. - =N. cara=, 117, =130=. - - =Narcomedusae=, 117. - - =Nassa=, 3, 10, 12, 327, 335, =390=. - =N. fossata=, 327, =391=. - =N. mendica=, 327, =391=. - =N. obsoleta=, 10, 12, 327, =390=. - =N. perpinguis=, 327, =391=. - =N. tegula=, 327, =391=. - =N. trivittata=, 10, 11, 327, =390=. - =N. vibex=, 327, =391=. - - =Nassidae=, 327, =390=. - - =Natica=, 311, 325, 334, =367=. - =N. canrena=, 325, =368=. - =N. clausa=, 325, =368=. - =N. heros=, =367=. - - =Naticidae=, 325, =366=. - - =Nauplius=, =248=, 251. - - =Nautilus=, 328, =467=. - - =Navicula ostrearia=, 435. - - Nekton, =23=. - - =Nemalion=, 76, =79=. - /N. multifidum/, 76, =79=. - - /Nemalionaceae/, 76, =79=. - - =Nemathelminthes=, 159, 161, =170=. - - =Nematoda=, 161, =170=. - - Nematophore, 118. - - Nemerteans, =167=. - - =Nemertes=, 160, =169=. - =N. socialis=, 160, =169=. - =N. viridis=, 160, =169=. - - =Nemertinea=, 160, =167=. - - =Neopanopeus=, 241. - =N. texana=, 241, =281=. - - Nephridia, =319=. - - Nephridium, 303. - - =Nephthydidae=, 161, =177=. - - =Nephthys=, 161, =178=. - =N. ingens=, 161, =178=. - =N. picta=, 161, =178=. - - =Nereidae=, 161, =176=. - - =Nereis=, 161, =176=. - =N. limbata=, 161, =177=. - =N. pelagica=, 161, =177=. - =N. virens=, 161, =177=. - - Nereocystis, 63, 70. - =N. Luetkeana=, =35=. - - =Nerine=, 161, =181=. - =N. agilis=, 161, =181=. - =N. coniocephala=, 161, =181=. - - =Nerita=, 325, =363=. - =N. peleronta=, 325, =363=. - =N. tessellata=, 325, =363=. - =N. versicolor=, 325. - - =Neritidae=, 325, =363=. - - =Neritina=, 311, 325, =363=. - =N. reclivata=, 325, =364=. - =N. viridis=, 325, =364=. - - Nervous system, =247=, =320=. - - =Neverita=, 309, 325, =368=. - =N. duplicata=, 11, 325, =367=. - =N. recluziana=, 325, =368=. - - =Nicothoe=, 239, =250=. - - =Nidorella=, 204, =210=. - =N. armata=, 204, =210=. - - =Nitophyllum=, 77, =85=. - =N. laceratum=, 77, =85=. - =N. punctatum=, 77, =86=. - =N. Ruprechteanum=, 77, =86=. - - Noah's-ark shell, 426. - - Node, 303. - - Nodules, 344. - - =Non-Calcarea=, 100, =104=, 106. - - =Norrisia=, 312. - - =Nostocaceae=, 48. - - =Nucula=, 309, 405, =422=. - =N. proxima=, 405, =422=. - - =Nuculidae=, 405, =421=. - - Nudibranch, 328, 349, 353. - - =Nudibranchiata=, 300, 324, =352=. - - Nullipores, =31=, 147. - - Nummulites, 22. - - - O - - =Obelia=, =125=. - =O. commissuralis=, 116, =125=. - - =Oceania=, =125=. - =O. languida=, 116, =125=. - - =Ocinebra=, 326, =384=. - =O. circumtexta=, =385=. - =O. interfossa=, 326, =385=. - =O. lurida=, 326, =384=. - =O. poulsoni=, 326, =384=. - - Octopi, 315. - - =Octopoda=, 301, =464=, 468. - - Octopus, 464, 468. - - =Oculina=, 141, =148=. - - =Ocypoda=, 11, 241, =282=. - =O. arenaria=, 241, 274, =282=. - - =Ocypodidae=, 241, =282=. - - Odontophore, =303=. - - =Oliva=, 10, 311, 313, 327, 334, =400=. - =O. literata=, 327, =400=. - - =Olivella=, 10, 312, 327, =400=. - =O. biplicata=, 327, =400=. - =O. boetica=, 327, =401=. - =O. mutica=, 327, =400=. - - =Olividae=, 327, =400=. - - =Ommastrephes=, 464, 468, =469=. - =O. illecebrosus=, 464, =469=. - - Opercula, 193. - - Operculum, 254, 303, =331=, 355. - - =Ophiocoma=, 213, =216=. - =O. aethiops=, 213, =216=. - =O. Alexandri=, 213, =216=. - =O. riisei=, 213, =216=. - - =Ophiopholis=, 213, =215=. - =O. aculeata=, 43, 213, =215=. - - =Ophiothrix=, 213, =216=. - =O. angulata=, 213, =216=. - - =Ophiurida=, 213, =215=. - - =Ophiuroidea=, 200, 213, =214=. - - =Opisthobranchiata=, 300, 324, 349, =350=. - - Oral, 202. - Surface, 201. - - Orbits, =243=. - - =Orchestia=, 11, 43, 242, =289=. - =O. agilis=, 242, =289=. - - Organ-pipe coral, =151=. - - Organs of feeling, =249=. - - Orifice, 190, 412. - - =Oscillaria=, 48, =49=. - - Osphradium, 303, =339=. - - Ossicles, 201, =203=, 218. - - =Ostracoda=, =238=. - - =Ostrea=, 405, 410, =435=. - =O. edulis=, 435. - =O. frons=, 405, =435=. - =O. lurida=, 405, =435=. - =O. virginica=, 310, 405, =435=. - - =Ostreidae=, 405, =432=. - - Otocysts, =165=, =303=. - - Otter Cliffs, =43=. - - =Ovalipes=, 241, =276=. - =O. ocellatus=, 241, =276=. - - Ovicell, 190, =193=. - - Oyster-crab, =287=. - - Oyster-culture, 432. - - Oysters, 321, 432. - Pearl-, 430, 431, 432. - - - P - - Pacific faunal divisions =311=. - - =Pacygrapsus=, 241, =282=. - =P. crassipes=, 241, =282=. - - =Padina=, 63, =71=. - =P. pavonia=, 63, =71=. - - =Paguridae=, 240, =264=. - - =Pagurus=, 240, =267=. - =P. bernhardus=, 240, =267=. - =P. longicarpus=, 240, =267=. - =P. pollicaris=, 240, =267=. - - =Palaemonetes=, 240, =260=. - =P. vulgaris=, 240, =260=. - - =Palaemon vulgaris=, =260=. - - Pallial line, 303, 418. - Sinus, 303, 419. - - Palps, =176=, 416. - - Palpus, =258=. - - Panamic province, =312=. - - =Pandora=, 407, =463=. - =P. trilineata=, 407, =463=. - - =Pandoridae=, 407, =463=. - - =Panopeus=, 12, =281=. - - =Pantopoda=, 242, =296=. - - =Panulirus=, 240. =263=. - =P. americanus=, =263=. - =P. argus=, 240, =263=. - =P. interruptus=, 240, =263=. - - Papillaceous, 303. - - Paraphyses, =72=. - - Parapodia, =171=. - - Parenchyma, 26. - - =Parypha=, =123=. - =P. crocea=, 116, =123=. - - =Peachia=, =144=. - - Pearls, 430, 431. - - =Pecten=, 309, 405, =435=. - =P. aequisulcatus=, 405, =438=. - =P. dislocatus=, 405, =437=. - =P. hastatus=, 405, =438=. - =P. irradians=, 405 =437=. - =P. islandicus=, 405, =436=. - =P. jacobius=, =436=. - =P. magellanicus=, 287, 405, =436=. - =P. tenuiscostatus=, 436. - - =Pectinidae=, 405, =435=. - - Pedal opening, 412. - - =Pedata=, 228, =231=. - - =Pedicellariae=, 201, =205=, =219=. - - =Pedicellina=, 189, =198=. - =P. americana=, 189, =198=. - - =Pelagia=, 133, =139=. - =P. cyanella=, 133, =139=. - - Pelagic, =23=. - Flora, 38. - - =Pelecypoda=, 301, 320, 321, 405, =409=, 420. - Classification of, =419=. - - =Peltogaster=, 239, =256=. - - Pen, 467. - - =Penaeus=, 240, =260=. - =P. brasiliensis=, 240, =260=. - =P. setiferus=, 240, =260=. - - =Penicillus=, 51, =58=. - =P. capitatus=, 51, =58=. - =P. dumentosus=, 51, =58=. - =P. Ph[oe]nix=, 51, =58=. - - =Pennaria=, =124=. - =P. gibbosa=, 116, =124=. - =P. tiarella=, 116, =124=. - - =Pennatula=, =141=. - =P. aculeata=, Plate XLVII. - =P. borealis=, Plate XLVII. - - =Pennatulacea=, 141, =153=. - - =Pentaceros=, 204, =210=. - =P. occidentalis=, 204, =210=. - =P. reticularis=, 204, =210=. - - =Pentacerotidae=, 204, =210=. - - =Pentacrinus=, 234, =235=. - - =Pentacta=, 228, =232=. - =P. frondosa=, 43, 228, =232=. - - =Pentagonasteridae=, 204, =209=. - - Pericardium, =341=, 416. - - =Pericolpa=, 133, =136=. - =P. quadrigata=, 133, =136=. - - =Peridinieae=, 38. - - =Periostracum=, =303=, 425. - - Perisaltic, 172. - - Perisarc, 118, =119=. - - Peristome, =190=, 194, 218, =303=. - - Peristomium, =176=. - - Periwinkles, =371=. - - =Perna=, 405, =432=. - =P. ephippium=, 405, =432=. - - =Peromedusae=, 133, =136=. - - =Petricola=, 407, =452=. - =P. carditoides=, 407, =452=. - =P. pholadiformis=, 407, =452=. - - =Petricolidae=, 407, =452=. - - =Petrocelis=, 78, =95=. - =P. cruenta=, 40, 78, =95=. - - =Petrolisthes=, 240, =270=. - =P. armatus=, 240, =270=. - =P. sexspinosus=, 240, =270=. - - =Peyssonnelia=, 78, =95=. - =P. Dubyi=, 78, =95=. - - =Phaeophyceae=, 28, 61, 62. - - Phanerogams, 25. - - =Phanerozonia=, =204=, =208=. - - =Phascolosoma=, 162, =186=. - =P. Gouldii=, 162, =186=. - - =Pholadidae=, 407, =460=. - - =Pholas=, 407, =460=. - =P. californica=, 407, =461=. - =P. costata=, 407, =461=. - =P. truncata=, 407, =461=. - - =Phoxichilidium=, 242, =297=. - =P. maxillare=, 242, =297=. - - =Phyla=, =19=. - - =Phyllitis=, 62, =66=. - =P. fascia=, 62, =66=. - - =Phyllodoce=, 161, =175=. - =P. gracilis=, 161, =175=. - - =Phyllodocidae=, 161, =175=. - - =Phyllolithodes=, 240, =271=. - =P. papillosus=, 240, =271=. - - =Phyllonotus pomum=, =382=. - - =Phyllophora=, 76, =81=. - =P. Brodiaei=, 76, =82=. - =P. membranifolia=, 76, =82=. - - =Phyllopoda=, =238=. - - =Phyllospora=, 63, =73=. - =P. Menziesii=, 63, =73=. - - Phylum, 19. - - =Phyncopodia helianthoides=, =207=. - - =Physalia=, =131=. - =P. arethusa=, 117, =131=. - - =Pikea=, 78, 94. - =P. californica=, 78, =94=. - - Pill-bugs, =291=. - - =Pinna=, 405, =431=. - =P. muricata=, 405, =431=. - =P. seminuda=, 405, =431=. - - =Pinnotheres=, 241, =287=. - =P. maculatum=, =287=. - =P. ostreum=, 241, =287=. - - =Pinnotheriidae=, 241, =287=. - - =Pitho=, 241, =286=. - =P. aculeata=, 241, =286=. - - =Placunanomia=, 405, =425=. - =P. macrochisma=, 405, =425=. - - =Planaria=, 160, =167=. - =P. grisea=, 160, =167=. - - Planarians, =166=. - - Planarian worms, 12. - - Plankton, =21=, 23. - - =Planocera=, 160, =166=. - =P. nebulosa=, 160, =166=. - - =Planula=, 120, =135=. - - =Platyhelminthes=, 159, 160, =164=. - - =Platyonichus ocellatus=, =276=. - - =Pleurobrachia=, 154, =156=. - =P. rhododactyla=, 154, =156=. - - =Pleurococcus=, 26. - =P. vulgaris=, =25=. - - =Plocamium=, 77, =85=. - =P. coccineum=, 77, =85=. - - =Plumularia=, =127=. - =P. falcata=, 116, =127=. - - Plumularians, 116, =127=. - - Pluteus, 201, =220=. - - Polian vessels, 201. - - =Polina=, 160, =170=. - =P. glutinosa=, 160, =170=. - - =Polychaeta=, 161, =172=. - - =Polycirrus=, 161, =182=. - =P. eximius=, 161, =182=. - - =Polycladida=, 160, =165=. - - =Polyides=, 78, =95=. - =P. rotundus=, 78, =95=. - - =Polymastia=, 100, =106=. - =P. robusta=, 100, =106=. - - =Polynices=, 12, 310, 314, 325, 335, =367=. - =P. duplicata=, 11, 325, 344, =367=. - =P. heros=, 8, 10, 44, 325, 343, =367=. - =P. lewisii=, 325, =368=. - =P. recluziana=, 325, =368=. - =P. triseriata=, 325, =367=. - - =Polynoe=, 161, =174=. - =P. squamata=, 161, =174=. - =P. sublevis=, 161, =174=. - - =Polyphemus=, =238=. - - Polypide, 190, =192=. - - =Polyplacophora=, 300, =321=. - - Polyps, 111, =114=, 119. - - =Polysiphonia=, 77, =87=. - =P. Baileyi=, 77, =88=. - =P. dendroidea=, 77, =87=. - =P. fastigiata=, 43, 77, =87=. - =P. fibrillosa=, 77, =88=. - =P. Harveyi=, 77, =88=. - =P. nigrescens=, 77, =87=. - =P. Olneyi=, 77, =88=. - =P. parasitica=, 77, =87=. - =P. urceolata=, 77, =88=. - =P. urceolata=, var. =formosa=, 77, =88=. - =P. variegata=, 77, =88=. - =P. violacea=, 44, 77, =88=. - =P. Woodii=, 77, =89=. - - =Polyzoa=, 8, 188, =191=. - - Polyzoans, 8, 12, 22. - - =Pontonema=, 161, 170. - =P. marinum=, 161, =170=. - - Porcelanous, =304=, 345. - - =Porcellana=, 240, =269=. - =P. sayana=, 240, =269=. - - =Porcellanasteridae=, 204, =208=. - - =Porcellanidae=, 240, =269=. - - Porcupine Island, =42=. - - =Porifera=, 100, =101=. - - =Porites=, =147=. - =P. astraeaoides=, Plate XLV. - =P. furcata=, Plate XLV. - - =Porocidaris=, 217, =222=. - =P. sharreri=, 217, =222=. - - =Porphyra=, 43, 78, =96=. - =P. laciniata=, 78, =96=. - =P. vulgaris=, 38, 78, =96=. - - =Porpita=, =132=. - - =Portunidae=, 241, =274=. - - Prawns, 258, =259=. - - Preserving invertebrates, =14=. - - =Prionitis=, 78, 94. - =P. Andersonii=, 78, =94=. - =P. lanceolata=, 78, =94=. - - Proboscis, =333=. - - =Procerodes=, 160, =167=. - =P. frequens=, 160, =167=. - - Propodium, =335=. - - =Prosobranchiata=, 300, 324, 349, =355=. - - Prostomium, =176=, 243. - - =Protista=, =22=. - - =Protobranchiata=, 301, 405, 420, =421=. - - =Protococcaceae=, 38. - - =Protococcus nivalis=, 25, =33=. - - =Protophyta=, =21=. - - =Protozoa=, =21=, 101. - - =Pseudolamellibranchiata=, 301, 405, 420, =429=. - - =Psilaster=, 204, =209=. - =P. florae=, 204, =209=. - - =Psolus ephippiger=, =231=. - =P. fabricii=, =232=. - - =Pterogorgia acerosa=, Plate XLVI. - - =Pteronotus=, 326, =384=. - =P. festivus=, 326, =384=. - - =Ptilota=, 78, =92=. - =P. densa=, 78, =92=. - =P. elegans=, 78, =92=. - =P. hypnoides=, 78, =92=. - =P. serrata=, 78, =92=. - - =Pugettia=, 241, =285=. - =P. gracilis=, 241, =285=. - - =Pulmonata=, 300, 331, 338, =349=. - - =Punctaria=, 62, =65=. - =P. latifolia=, 62, =65=. - =P. plantaginea=, 62, =66=. - =P. tenuissima=, 62, =66=. - - =Purpura=, 8, 9, 309, 312, 326, =386=, 387. - =P. crispata=, 326, =387=. - =P. haemastoma=, 326, =387=. - =P. lapillus=, 41, 42, 314, 326, =386=. - =P. lima=, 326, =387=. - =P. patula=, 326, =386=. - =P. saxicola=, 326, =387=. - - =Purpurinae=, 326, =385=. - - =Pycnogonida=, 242, =296=. - - =Pycnogonidae=, 9. - - =Pylopagurus=, =268=. - - Pyloric caeca, =208=. - - =Pyrocystis noctiluca=, =33=. - - =Pyrosoma=, 472. - - =Pyrosomata=, 472. - - =Pyrula=, 10, 326, =379=. - =P. papyratia=, 326, =379=. - - - R - - =Radiata=, =113=. - - Radiates, 20. - - Radula, 304, =317=, =340=. - - =Raeta=, 406, =447=. - =R. canaliculata=, 406, =447=. - - =Ralfsia=, 62, =65=. - - =Ralfsiaceae=, 62, =65=. - - =Rataria=, =132=. - - Receptacles, =72=. - - Red crab, =278=. - - Red seaweeds, 76, =79=. - - Red snow, =33=. - - Reef-builders, =147=. - - Reef-corals, 142, =146=. - - =Regularia=, 217. - - Reticulated, =304=. - - =Rhabdoc[oe]lida=, 160, =167=. - - =Rhabdonia=. 77, =83=. - =R. Coulteri=, 77, =84=. - =R. tenera=, 77, =83=. - - =Rhithropanopeus=, 241. - =R. harrisii=, 241, =281=. - - =Rhizocephala=, 239, =256=. - - =Rhizophyllideae=, 78, =95=. - - =Rhizostomae=, 133, =139=. - - =Rhodactinia=, 141, =145=. - =R. davidsii=, 141, =145=. - - =Rhodomela=, 77, =89=. - =R. floccosa=, 77, =90=. - =R. larix=, 77, =90=. - =R. Rochei=, 77, =89=. - =R. subfusca=, 77, =89=. - - =Rhodomeleae=, 77, =86=. - - =Rhodophyceae=, 28, 76, =79=. - - =Rhodophyllideae=, 77, =83=. - - =Rhodophyllis=, 77, =83=. - =R. veprecula=, 77, =83=. - - =Rhodospermeae=, 79. - - =Rhodymenia=, 77, =85=. - =R. palmata=, 38, 42, 43, 77, =85=. - - =Rhodymeniaceae=, 77, =84=. - - =Rhodymenieae=, 77, =85=. - - Ring-canal, 201, =203=. - - Rock-crab, 277, =280=. - - Rockweeds, =8=. - - Rocky shores, =7=. - - Rodicks Weir, 44. - - Root-mouth jellyfishes, =139=. - - Rostrum, 243. - - Roundworms, =170=. - - - S - - =Sabella=, 162, =184=. - =S. microphthalma=, 162, =184=. - - =Sabellidae=, 162, =184=. - - =Sacculina=, =239=, =256=. - - =Sagartia=, 141, =145=. - =S. leucolena=, 141, =145=. - - =Salpa=, 472, 474, =475=. - - Sand-crab, =282=. - - Sand-dollar, 11, 44, =225=. - - Sandpiper, =5=. - - Sandy shores, =10=. - - =Sapphirina=, 239, =250=. - - Sargasso Sea, =33=. - - =Sargassum=, 26, 63, 64, =73=. - =S. bacciferum=, 34, 35, 63, =74=. - =S. Montagnei=, 63, =74=. - =S. vulgare=, 63, =74=. - - =Sarsia=, 116, =123=. - =S. mirabilis=, =123=. - - =Saxicava=, 41. - - =Saxidomus=, 406, =452=. - =S. nuttallii=, 406, =452=. - - =Scala=, 325, =365=. - =S. angulata=, 325, =366=. - =S. groenlandica=, 325, =366=. - =S. lineata=, 325, =366=. - =S. multistriata=, 325, =366=. - - =Scalidae=, 325, =365=. - - Scallops, 12. - - =Scaphopoda=, 320, 321, 327, =402=. - - =Schizaster=, 217, =227=. - =S. fragilis=, 217, =227=. - - =Schizopoda=, 239, =257=. - - =Scinaia=, 76, =80=. - =S. furcellata=, 76, =80=. - - =Scrobicularia=, 413. - - Sculpture, =304=. - - =Scurria=, 312. - - Scuta, =254=. - - =Scutellidae=, 217, =225=. - - =Scyllarus=, 258, =263=. - - =Scyphozoa=, 112, 115, 133, =134=. - - Sea-acorns, =254=. - - Sea-anemones, 112, =142=. - - Sea-blubbers, 134. - - Sea-colanders, 42, =69=. - - Sea-cucumbers, 43, 200, 202, =229=. - - Sea-eggs, =221=. - - Sea-fans, 114, 115, 142, 147, =152=. - - Sea-feathers, =152=. - - Sea-hares, =351=. - - Sea-lilies, 200, =234=. - - Sea-mats, =192=. - - Sea-otters' cabbage, =35=. - - Sea-peach, =476=. - - Sea-pens, 142, =153=. - - Sea-slugs, =349=. - - Sea-spiders, 9, =296=. - - Sea-squirts, =474=. - - Sea-urchins, 43, 114, 200, 203, =218=, 220. - - Sea-whips, 142, =152=. - - =Sedentaria=, 161, =180=. - - Segment, 243. - - Segmented worms, =170=. - - =Semostomae=, 133, =137=. - - Sense-organs, =135=. - - =Sepia=, 464, 467, 468. - - =Septibranchiata=, 420. - - =Serpula=, 162, =185=. - =S. dianthus=, 162, =185=. - - =Serpulidae=, 162, =184=. - - =Sertularia=, =126=. - =S. argentea=, 43, 116, =127=. - =S. cupressina=, 116, =127=. - =S. pumila=, 43, 116, =126=. - - Sertularians, 8, 116, 120, 121, =126=. - - Sessile, 121, 126. - - Sheep-crab, =285=. - - Sheepswool sponge, 104, =108=. - - Shell-- - Butterfly-, 323. - Coffee-, 379. - Conch-, 377. - Cowry-, 377. - Gasteropod, =342=. - Growth of gasteropod, 346. - Mounds, 432. - Noah's-ark, 426. - Peach-, 454. - Pelecypod, =416=, 417. - Razor-, 457. - Setting-sun, 444. - - Shipworm, 462. - - Shrimps, =240=, 245, 258, =259=. - - =Sigaretus=, 311, 325, 334, =369=. - =S. perspectivus=, 325, =369=. - - Signs on the beach, =1=. - - Singing Beach, =2=. - - Sinistral, 304, =345=. - - Sinuate, 304. - - =Sipho=, 309, 313, 327, =393=. - =S. islandicus=, =393=. - =S. pygmaeus=, 327, =394=. - =S. Stimpsoni=, 327, =393=. - - Siphon, 304, =330=, 334, =411=. - Anal, 412. - Branchial, 412. - Excurrent, 412. - Functional, 411. - Incurrent, 412. - - =Siphonalia=, 327, =394=. - =S. kellettii=, 327, =394=. - - =Siphoneae=, 51, =56=. - - Siphonoglyphs, =143=. - - =Siphonophora=, 117, 120, =121=, =130=. - - Siphonozooeids, =150=. - - Siphuncle, 468. - - =Sipunculoidea=, 162, =185=. - - =Sipunculus=, 162, =185=. - =S. nudus=, 162, =185=. - - Skates, 12, 44. - - =Solaster=, 204, 205, =211=. - =S. decemradiata=, 204, =211=. - =S. endeca=, 204, =211=. - - =Solasteridae=, 204, =211=. - - =Solen=, 407, =458=. - =S. ensis=, 3, =458=. - =S. rosaceus=, 407, =458=. - =S. sicarius=, 407, =458=. - =S. viridis=, 407, =458=. - - =Solenidae=, 407, =457=. - - =Solenogastres=, 321. - - =Solenomya=, 405, =423=. - =S. borealis=, 405, =423=. - =S. velum= 405, =423=. - - =Solenomyidae=, 405, =423=. - - Somite, 243. - - Sow-bugs, =291=. - - =Spatangoidae=, 217, =226=. - - =Spatangoidea=, 217, =226=. - - Species, 20. - - Specific name, 28. - - =Sphacelaria=, 62, =65=. - =S. cirrhosa=, 62, =65=. - =S. radicans=, 62, =65=. - - =Sphacelariaceae=, 62, =65=. - - =Sphaeoplea annulina=, 37. - - Sphaeridia, 219. - - =Sphaerococceae=, 77, =84=. - - =Sphaeroma=, 242, =293=. - =S. destructor=, =293=. - =S. quadridentatum=, 242, =293=. - - Spicules, 102. - - Spider-crabs, 241, =284=. - - Spines, 201, 205, 221. - - =Spionidae=, 161, =181=. - - Spire, 304. - - =Spirorbis=, 8, 12, 162, =185=. - =S. borealis=, 162, =185=. - - =Spirula=, 464, 467, 468. - - =Spirulina=, 48, =49=. - - Sponges, 100, =101=. - - =Spongia=, =104=. - =S. graminea=, =109=. - - =Spongidae=, 100. - - =Spongillidae=, =104=. - - Spongin, =102=. - - Spring-tides, =13=, 15. - - =Spyridia=, 78, =92=. - =S. filamentosa=, 78, =92=. - - =Squamarieae=, 78, =95=. - - Squame, 243. - - Squids, 464. - - =Squilla=, 241, =288=. - =S. empusa=, 241, =288=. - - Starfishes, 43, 114, 200, 203, 204, =205=, 434. - - Station and habits of the Mollusca, =313=. - - =Stauromedusae=, 133, =136=. - - =Stelosponginae=, 100. - - =Sternogramme=, 76, =82=. - =S. interrupta=, 76, =82=. - - =Sternorhynchus=, 241, =286=. - =S. sagittarius=, 241, =286=. - - =Stomatopoda=, 241, =288=. - - Stone-canal, 201, =203=. - - Stone-crab, =280=. - - Stony corals, 112, 115, =146=. - - Striae, =344=. - - Strobila, =135=, 138. - - =Strombidae=, 326, =375=. - - =Strombus=, 10, 311, 326, =376=. - =S. alatus=, =376=. - =S. gigas=, 326, =376=, 431. - =S. pugilis=, 326, =376=. - - =Strongylocentrotus=, 217, =223=. - =S. drobachiensis=, 41, 43, 217, =223=. - =S. franciscanus=, 217, =223=. - =S. purpuratus=, 217, 221, =223=. - - Structure of mollusks, =315=. - - =Stylochopsis=, 160, =166=. - =S. littoralis, 160=, =166=. - - =Suberites=, 100, =106=. - =S. compacta=, 100, =106=. - - =Suberitidae=, 100. - - Suborders, 29. - - Subumbrella, =120=. - - Suckers, 201, =203=. - - Sun-jellies, 134, =138=. - - Suture, 304, =344=. - - Swimming-bell, 120. - - Swimming crabs, 241. - - =Syconidae=, 100. - - =Syllidae=, 161, =173=. - - Symmetry, =328=. - - =Synapta=, 228, 229, =233=. - =S. roseola=, 228, =233=. - =S. rotifera=, 228, =233=. - =S. tenuis=, 228, =233=. - =S. viviparia=, =231=. - - - T - - Table: Classification of algae-- - Blue-green, =48=. - Brown, =62=. - Grass-green, =51=. - Red, =76=. - Classification of-- - Actinozoa, =141=. - Arthropoda, =238=. - Asteroidea, =204=. - Cephalopoda, =464=. - Chordata, =472=. - Ctenophora, =154=. - Echinoidea, =217=. - Holothuroidea, =228=. - Hydrozoa, =116=. - Mollusca, =300=. - Molluscoida, =188=. - Ophiuroidea, =213=. - Pelecypoda, =409=. - Porifera, =100=. - Scyphozoa, =133=. - - =Tagelus=, 310, 407, =459=. - =T. gibbus=, 407, =459=. - - =Talitrus longicornis=, =289=. - - =Talorchestia=, 242, =289=. - =T. longicornis=, 242, =289=. - =T. megalophthalma=, =290=. - - =Taonia=, 63, =71=. - =T. atomaria=, 63, =71=. - - =Tapes=, 406, =451=. - =T. laciniata=, 406, =451=. - =T. staminea=, 406, =451=. - - =Tealia crassiformis=, =145=. - - =Tectarius=, 311, 326, =373=. - =T. muricatus=, 326. - =T. nodulosus=, 326, =373=. - - =Tectibranchiata=, 300, 324, =350=. - - =Tedania=, 100, =107=. - - Teeth, =304=, 417, 418. - Cardinal, 418. - Lateral, 418. - - =Tellina=, 311, 406, =443=. - =T. alternata=, 406, =444=. - =T. bodegensis=, 406, =444=. - =T. radiata=, 406, 443, =444=. - =T. tenera=, 406, =444=. - - =Tellinidae=, 406, =443=. - - Telson, 243, =247=. - - Tentaculocysts, =135=. - - =Terebellidae=, 161, =182=. - - =Teredinidae=, 407, =462=. - - =Teredo=, 407, =462=. - =T. navalis=, 13, 407, =462=. - - Terga, =254=. - - Terms used in describing Crustacea, =243=. - Echinoderms, =201=. - Hydroids, =118=. - Mollusks, =302=. - Polyzoa, =190=. - - Testaceous, =304=. - - =Tetrabranchiata=, 301, 464, =467=. - - =Tetrastemma=, 160, =169=. - =T. arenicola=, 160, =169=. - - =Thalassiophyllum=, =36=, 63, 70. - - =Thaliacea=, 472. - - Thallophytes, 25. - - Thallus, 26. - - =Thelepsus=, 161, =182=. - =T. cincinnatus=, 161, =182=. - - Thorax, 243, =246=. - - =Thracia=, 309. - - =Thyone=, 228, =231=. - =T. briareus=, 228, =231=. - - =Tima=, =128=. - =T. formosa=, 116, =128=. - - =Tivela=, 406, 410, =450=. - =T. crassatelloides=, 406, =450=. - - Toad-crab, =285=. - - =Toxopneustes=, 217, =224=. - =T. variegatus=, 217, =234=. - - =Trachylinae=, 117, 120, =128=. - - =Trachymedusae=, 117, =128=. - - =Trachynema=, =128=. - =T. digitale=, 117, =128=. - - Transatlantic province, =309=. - - =Trematoda=, =160=. - - =Trichodesmium=, =33=. - - =Trichotropis=, 309. - - =Tricladida=, 160, =166=. - - Triclads, =166=. - - =Tridacna gigas=, 313, =419=. - - =Triforis=, =374=. - - =Tritonidea=, 327, =394=. - =T. tincta=, 327, =394=. - - =Trivia=, 326, =378=. - =T. californica=, 326, =379=. - =T. pediculus=, 326, =378=. - =T. quadripunctata=, 326, =379=. - =T. solandri=, 326, =379=. - =T. spadacea=, =379=. - - =Trochidae=, 325, =359=. - - =Trochiscus=, 325, =362=. - =T. norrisi=, 325, =362=. - - =Trophon=, 309, 326, =383=. - =T. clathratus=, 326, =383=. - - Tube-feet, =203=. - - =Tubicola=, 161, =172=. - - Tubicolous worms, =180=. - - =Tubipora=, 141, 147, =151=. - - =Tubularia=, 116. - =T. Couthouyi=, 116, =123=. - =T. indivisa=, 116. - - Tubularians, 116, 121, =122=. - - =Tubulipora=, 188, =194=. - =T. flabellaris=, 188, =194=. - - =Tunicata=, 472. =474=. - - Tunicates, 474. - - =Turbellaria=, 160, =165=. - - Turbinate, =304=. - - =Turbinellidae=, 327, 394. - - =Turbinidae=, 325, =362=. - - =Turbo=, 325, =363=. - =T. castaneus=, 325, =363=. - =T. castaneus, var. crenulatus=, 325, =363=. - - Tyrian purple, 386. - - - U - - =Uca=, 241, =282=. - =U. minax=, 241, =282=. - =U. pugilator=, 241, =282=. - =U. pugnax=, 241, =282=. - - =Udotea=, 51, =58=. - =U. conglutinata=, 51, =58=. - =U. flabellata=, 51, =58=. - - =Udoteaceae=, 51, =58=. - - =Ulothrix=, 51, =53=. - - =Ulva=, 26, 28, 29, 51, =55=. - =U. lactuca=, 51, =55=. - =U. latissima=, 51, =55=. - =U. Linza=, =56=. - =U. rigida=, =55=. - - =Ulvaceae=, 28, 51, 52, 53, =54=. - - Umbilicus, 304, =344=. - - Umbo, 304, 417. - - Uncini, 180. - - Univalves, =306=, 307, 314. - - =Urochorda=, 472, =474=. - - =Urosalpinx=, 11, 326, =383=, 434. - =U. cinerea=, 314, 326, =383=. - - Uses of algae, =37=. - - - V - - =Valoniaceae=, 51, =56=. - - Valve, =409=, 416. - - Varices, 304, 344, =347=. - - Vegetative reproduction, 27. - - =Vellela=, =131=. - =V. limbosa=, 117, =131=. - - Velum, =134=. - - =Velutina=, 309. - - Velvet sponge, 104. - - =Veneridae=, 406, =447=. - - Venons sinuses, =247=. - - Ventral surface, 201. - - Ventricose, =304=. - - =Venus=, 406, 410, =448=. - =V. cancellata=, 406, =449=. - =V. mercenaria=, 406, =448=. - =V. mercenaria, var. mortoni=, 406, =449=. - - Venus's flower-basket, =102=. - Girdle, =157=. - - =Vermes=, =163=. - - =Vermetidae=, 326, =375=. - - =Vermicularia=, 326, =375=. - =V. spirata=, 326, =375=. - - Vertebrates, =19=. - - =Vesicularia=, 189, =198=. - =V. custata=, 189, =198=. - =V. dichotoma=, 189, =198=. - - Vibracula, 190, =193=. - - Visceral mass, 415. - - =Voluta=, 313, 327, =398=. - =V. junonia=, 327, 398, =399=. - - =Volutidae=, 327, =398=. - - Vulgar names, 29. - - - W - - Walking crabs, =241=. - - Water-vascular system, 201, 202, =206=, 231. - - West Indian division, 24. - - Wharves and bridges, 13. - - Whelks, 44. - - Whorl, 304, =343=. - - Whorls, nepionic, 344. - - Worms, 159, =163=. - Bristle-, 171. - Chaetopod, 172. - Clam-, 176. - Flat-, 164. - Nemertean, 167, 169. - Polychaete, 172. - Polyclad, 165. - Round-, 170. - Segmented, 170. - Tubicolous, 180. - - - X - - =Xiphosura=, 242, =294=. - - =Xylotrya=, 462. - - - Y - - Yellow sponge, 104. - - =Yoldia=, 309, 405, =422=. - =Y. limatula=, 405, =422=. - =Y. sapotilla=, 405, =423=. - =Y. thraciaeformis=, 405, =432=. - - - Z - - =Zirphaea=, 407, =461=. - =Z. crispata=, 407, =461=. - - =Zoantharia=, 141, =142=. - - Zoarium, 190, =192=. - - =Zoea=, =248=, 263, 273. - - Zo[oe]cium, 190, =192=. - - =Zonaria=, 63, =70=. - =Z. lobata=, 63, =70=. - - Zooeids, 118, =119=. - - Zooephytes, 113, 119. - - =Zostera marina=, 12. - - =Zygodactyla=, =128=. - =Z. groenlandica=, 116, =128=. - - - -CORRIGENDA - - Page 6. Second line from the bottom, for "they" read: Anemones. - 41. Line 20, for "/m[oe]nas/" read: /maenas/. - 43. Last line, for "they" read: animals. - 44. Line 27, for "/Cyania/" read: /Cyanea/. - 102. Last line, for "/flagellaete/" read: /flagellate/. - 196. Line 27, for "species" read: specimens. - 224. Line 16, for "/lunales/" read: /lunules/. - Plate LXXXIV, 6. For "/Glvcimeris/" read: /Glycimeris/. - - - - -TRANSCRIBER'S NOTE - -The original text has been retained as printed, with some exceptions. - -Illustrations have been moved from within paragraphs to nearby -spots between paragraphs. Page numbers from the printed 1901 -edition are indicated like this: "[pg235]". - -As mentioned on page 29 of the book, typography was used in a -specific way to visually distinguish various taxonomic classes. -This simple text edition will indicate text that was originally -printed with both small-caps and bold applied with "~", e.g. -"Suborder ~CHAETANGIEAE~". Text that originally had both italics -and bold applied is indicated herein by "^". Thus "Species ^L. -majuscula^". Text that was originally small-caps with or without -bold is all uppercase. Text that was originally italics without -bold is displayed herein with "/", thus "Genus /Griffithsia/". Text -that was originally bold without italics or small caps is indicated -with "=", thus "Class =ALGAE=". The original variations in font-size -are not carried into this version. - -Many of the biological classification schemes shown in this book were -printed with large curly brackets "{" extending several lines high. -For example, on page 18, a classification scheme was printed similar -to this: - - /Rhodymeniaceae/, {/Callithamnion/ - suborder {/Griffithsia/ - /Ceramieae/ {/Ceramium/ - -except that the three "{" were not printed, but were replaced by -a single tall "{". This typography does not generally work well -in current electronic books. Therefore, tables or schemes of this -sort have (except on page 18) been replaced by a different format -(nested list with tables) employing rearrangement and indentation, -without curly brackets--like this: - - Order /Rhodymeniaceae/ - - Suborder /Ceramieae/ - - Genera - - /Callithamnion/ - /Griffithsia/ - /Ceramium/ - -There are rare instances when this could cause confusion. For -example, the partial paragraph that preceeds the page 18 example -shown above: - - The genera of an order are then placed within a cover and labeled - in the same way, the legend then having the name of the order on - the left and the genera on the right of the bracket, thus: - -refers to a bracket no longer present in this version, and "left" and -"right" are perhaps no longer meaningful. - -Page 102: "flagell[oe]te Infusoria" was changed to "flagellate -Infusoria" to match the corresponding index entry. - -Page 150: in "The strictures forming the lobes", changed "strictures" -to "structures". - -Page 154: changed "rhododaciyla" to "rhododactyla". - -Page 172: changed "perisaltic" to "peristaltic". - -Page 188: in the table showing the classification of the Mulluscoida, -there are grouping words such as "Articulata", "Inarticulata", and -"Flustrina", which are not labeled as to whether they are taxonomic -"Family", or some other class. The transcriber has chosen to label -them "Set", which term is not elsewhere used in the book to denote a -formal taxonomic class. The same sort of thing is done on a few other -pages, e.g. on page 240, for the group "Free-swimming Forms". - -Page 196: "Phyllopora" changed to "Phyllophora"--a guess. - -Page 216 (facing), Plate LV.: "Ophiocoma [oe]thiops" changed to -"Ophiocoma aethiops". - -Page 233: "rows" to "Rows", in "rows of tube-feet lie near together,". - -Page 239, and perhaps elsewhere: notes such as "without gills or -thoracic legs" that were printed with the Genera, in this example -/Mysis/, have been moved into the note attached to a next higher -taxonomic class, i.e. Order Schizopoda, with added text necessary for -clarification. - -Page 362: "f dation" to "foundation" in "greenish-white nacreous -f dation". - -Page 486: the index entry "Pacific faunal divisions" had no page -number. The number "=311=" seems correct, and has been inserted. - -Index, "Endendrium ramosum, Plate XLI." entry is removed, and "Plate -XLI" is added to entry "Eudendrium ramosum". - -Index, entry "Ventricosa" changed to "Ventricose". - -Corrigenda: The corrections listed therein have been applied to the -text. In addition to the listed corrections, there were two other -instances of "lunales", on pp 225 and 226, now changed to "lunules"; -also "lunale" to "lunule" on p 225. - - - - - -End of Project Gutenberg's The Sea-beach at Ebb-tide, by Augusta Foote Arnold - -*** END OF THIS PROJECT GUTENBERG EBOOK THE SEA-BEACH AT EBB-TIDE *** - -***** This file should be named 43946.txt or 43946.zip ***** -This and all associated files of various formats will be found in: - http://www.gutenberg.org/4/3/9/4/43946/ - -Produced by Chris Curnow, RichardW and the Online -Distributed Proofreading Team at http://www.pgdp.net (This -file was produced from images generously made available -by The Internet Archive) - - -Updated editions will replace the previous one--the old editions -will be renamed. - -Creating the works from public domain print editions means that no -one owns a United States copyright in these works, so the Foundation -(and you!) can copy and distribute it in the United States without -permission and without paying copyright royalties. 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