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ALBERT R. MANN
LIBRARY

NEw York STATE COLLEGES
OF
AGRICULTURE AND HoME ECONOMICS

AT

CORNELL UNIVERSITY

ne University Library
QH 91.A

guide to the

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Cornell University

Library

The original of this book is in
the Cornell University Library.

There are no known copyright restrictions in
the United States on the use of the text.

http://www.archive.org/details/cu31924003000241

THE
SEA-BEACH AT EBB-TIDE

A GUIDE TO THE STUDY OF
THE SEAWEEDS AND THE
LOWER ANIMAL LIFE FOUND
BETWEEN TIDE-MARKS Ye

BY
AUGUSTA FOOTE ARNOLD

WITH MORE THAN
600 ILLUSTRATIONS

NEW YORK
THE CENTURY CO.
1901

PREFACE

HIS 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 varie-

ties 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 sat-
isfactory 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. Mor-
phology, 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 cgmmon names;
and, as a matter of fact, the reader will find that a scientific name
is as easily remembered as a common one. Technical phrase-

ology has, however, been avoided as much as possible, even at the
Vv

vi PREFACE

expense of conciseness and precision ; where it, has heen 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 alg, 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 neces-
sitating serious study. Marine organisms are interesting ac-
quaintances 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 per-
sons 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.

PREFACE vil

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 alge 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 permis-
sion to use cuts from the “Cambridge Natural History,” Parker
and Haswell’s “Zodlogy,” 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 Zodlogy”; to Wilhelm
Engelmann for a cut from “Die natiirlichen 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
eut from MeMurrich’s “ Invertebrate Morphology”; to Houghton,
Mifflin & Co. for cuts from the “Riverside Natural History”
and Agassiz’s “Seaside Studies in Natural History”; to the Com-
monwealth 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.

CORRIGENDA

Page 6. Second line from the bottom, for ‘‘ they” read: Anemones.

41. Line 20, for ‘ menas” read: menas.

43. Last line, for “ they” read: animals.

44. Line 27, for ‘‘ Cyania” read: Cyanea.

102. Last line, for ‘ flagellete” read: flagellate.
196. Line 27, for “‘ species” read: specimens.
224. Line 16, for ‘‘ lunales” read: lunules.

Plate LXxxIv, 6. For “ Glocimeris” read: Glycimeris.

CONTENTS

INTRODUCTION
PAGE
1 Signsonthe Beach . 2. we 6 we eee ee ee te ee
m Collecting. © 6 6. ee ee ee, eiike At cat Ae . 6
mt Classification. . . ep ote NE GE Oe ee eG ea a TD
iv Animal Life in its Lowest Forms ............. 4. 21
v Distribution of Animal LifeintheSea ........... . . 2
vi Some Botanical Facts about Algw . . . . . 1 1. ew ew ee ee ee
vit Naming of Plants . 2. 2 1 we ee ee ee ee eee ee ee 8
vir Distribution of Alge. . ....... oh RB @ wey eo e 2 BO
1x Some Peculiar and Interesting Varieties of Alge . ...... =. . 32
x Usesof Alge. ... ends By. bas. “ap ilo hay » Say dbs Se Ue (Ua? TRO. Gov Aytc hee Sag Nee AO
x1 Collecting at Bar Harbor ........ i Se ae ae i ee ee FO
PART I
: Marine ALG
1 BuugE-GREEN SEAWEEDS. .....- .-.. . ee 6 « AT
(CYANOPHYCEZ)
GRass-GREEN SEAWEEDS .... 6. se ee ee ee AF
(CHLOROPHYCEZ)
Ir OLIVE-GREEN AND Brown SEAWEEDS. ........ 61
(PHHOPHYCE)
mi Rep SEAWEEDS ... . Pee ioe G8 Se a on TS
(RHODOPHYCE4 OR FLORIDER)
PART II
MaRINE INVERTEBRATES
1 Ponrrera (SPONGES)... - - ee ee ee ee ee 99
11 C@LENTERATA (POLYPS. . . . . 6. ee) ss ss TT

ix

CONTENTS

MARINE INVERTEBRATES (Continued)

mi WorMS. ....... 4. aoe ee ge
(PLATYHELMINTHES, NEMATHELMINTHES, ANNULATA)
TV MOLUUSGOIDA. 2) a a ee ee ww i
v ECHINODERMATA . . . es + + ew ew wee
VI ARTHROPODA. . . 2 + 2 6 6 ee ew we ew ee
vil MontuscA. . . .. . a > ee eo
Vill CHORDATA, <i) a). Gee ee ES aw oe a

INDEX 4. ie HOE ORE aR Om

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

HE 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 obser-
vant 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 ever-
lasting, but the fury of the sea, which knows no invincible adver-
sary, 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
1 1

2 INTRODUCTION

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.?

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
“each-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 siciopncas holding myriads of the
dead. ‘If ghosts be ever laid, here lie ghosts of creatures innu-
merable, vexing the mind = 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 other-
wise disturbed. On some beaches these sounds resemble rumbling,
on others hooting; sometimes they are bell-like and even rhyth-
mical. 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

1 Huxley.

SIGNS ON THE BEACH 3

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 ex-
tremity, 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

4 INTRODUCTION

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, ac-
ceptance, 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.

Following the key further, he draws more conclusions. The
tracks are not in pairs, so the bird does not belong to the perch-
ers; therefore it must be a wader ora swimmer. There are no
web-marks to indicate the latter; hence it is a three-toed walk-
ing 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 isshown 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 entan-

gled; and so on. These combined characteristics belong to one

class of birds and to no other; so he knows as definitely as
1 Elliott Coues.

SIGNS ON THE BEACH 5

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 natu-
ralist 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 “ foot-
prints 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 unim-
portant 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.

II
COLLECTING

T has been said that everything on the land has its counterpart
in the sea. But all land animals are separate and indepen-
dent individuals, while many of those of the sea are united into
organic associations comprising millions of individuals insepara-
bly connected and many of them interdependent, such as corals,
hydroids, ete. 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 con-
cealment. This is effected not only by actual hiding, but very
generally by mimicry in simulating the color of their surround-
ings, 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.
They also have stinging threads (nematophores), which they dart
out for further defense.

6

COLLECTING 7

The study of biology has great fascination, and the subject
seldom fails to awaken interest as soon as the habit of observa-
tion 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 incpn-
spicuous 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 delight-
ful 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 algze 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 ani-
mals which could not live in more open and exposed places. The

8 INTRODUCTION

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 pro-
fusion, 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 plentifu'-
ness. 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 sup-
port. 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. Calecareous
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 iso-
pods, 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

COLLECTING 9

them the curious little sea-spiders (Pycnogonide), 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 diffi-
cult 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, Acmea, 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 per-
haps 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 nudi-
branch. 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 sea-
weeds, often of the red varieties, sea-anemones, hydroids, poly-
zoans, crustaceans, mollusks, and ascidians. Crabs will be snugly

10 INTRODUCTION

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 branchie, and s0 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 Dona., 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

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.

COLLECTING 11

drilled by the file-like tongue, or lingual ribbon, of Polynices,
Urosalpina, 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 sand-
hoppers (Orchestia). These often rise about the feet as do grass-
hoppers in the fields.

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 care-
ful examination, for here will be found many things belonging
to other shores and deep water. It is often alive with sand-
hoppers, 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 ex-
amples of species one would like to find in better condition, but
good specimens of which elude ordinary search or are unobtain-
able except by dredging.

Egg-cases form another class of objects which are often
gathered with no idea of their identity. Of these the most com-
mon are the long strings of saucer-like capsules which contain
the eggs of the mollusk Fulgur, those having square edges being

12 INTRODUCTION

the egg-cases of F. carica, and those having sharp edges those of
F. canaticulata, 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.” Cylindri-
eal piles of little capsules, sometimes called “ears of corn,” hold
the eggs of Chrysodomus. The irregular masses of small hemi-
spherical 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 abun-
dantly, 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 vineta,
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 poly-
zoans, 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 Massa obso-
leta,—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 com-
mon are the “fiddlers,” which honeycomb the banks and the sur-
face 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 shal-
low water and in all sorts of hiding-places along the shore. It

COLLECTING 13

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 beau-
tiful 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 lignorwm, 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 diffi-
cult. 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 danaé, 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.

14 INTRODUCTION

EQUIPMENT FOR COLLECTING INVERTEBRATES

The equipment for collecting upon sandy beaches is a shovel,
a sieve, anda 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, crus-
taceans, and worms. By washing out the sand in the sieve the
smallest specimens, which might otherwise escape notice, may be
secured. Ona rocky beach a strong knife and a net are suffi-
cient. Itis 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 aleohol becomes colored and sedi-
ment falls to the bottom of the jar, the animal is degenerating,
and the alcohol should be changed. Specimens for transporta-
tion 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 con-
venient 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 de-
layed until one reaches home. Labels should be used, giving
name when known, or a number when the name is not known,

COLLECTING 15

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 sea-
weeds should be put into the basket. The pails, half filled with
sea-water, will receive the other specimens, fine and delicate alge
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 alge; 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

16 INTRODUCTION

especial care in this respect should be taken with red alge, 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 snilteiauiely, SO
that when mounted it will not be too thick and the characteris-
tics 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 suffi-
cient to enable one to separate the branchlets or ultimate ramifi-
cations. 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

COLLECTING 17

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 speci-
mens 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
2

18 INTRODUCTION

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 con-
tains, thus:
C. rubrum
Ceramium 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, thus:

Khodymeniacee, ¢ Callithamnion
suborder Griffithsia
Ceramiew 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.

III
CLASSIFICATION

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 rec-
ognized 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 untu-
tored 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 struc-
ture 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 vertebre, while the lower animals, or inver-

tebrates are without a spinal column, and depend for stability
19

20 INTRODUCTION

upon muscles or coriaceous or calcareous coverings. The verte-
brates are first represented in the fish-like forms. Bilateral sym-
metry, 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, ete. ;
histologv. the character of the tissues of the body; and embry-
ology, t of the development of the animal from the
embryo y. 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 differ-
ences, a system of classification has been arranged with the fol-
lowing divisions:

Kingdom, Phylum, Class, Order, Family (or Suborder), Genus,
Species.

IV

ANIMAL LIFE IN ITS LOWEST FORMS

HE 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 divi-
sions 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 zodlo-
gists 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 re-
spectively 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
21

22 INTRODUCTION

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 repre-
sented 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 Foraninifera.

Many of the lower animals resemble plantsin 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 natnre of corals was for a long time considered to
be refut iestimony of a naturalist who declared that he
had set 1 bloom. Later this class of animals was
believed to occupy an intermediate sphere and partake of the
characteristics of both kingdoms. The name zodphyte, 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.

Vv
DISTRIBUTION OF ANIMAL LIFE IN THE SEA

LL 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. Hach 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 recog-
nized 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 accord-
ing 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, ete., 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

23

24 INTRODUCTION

coast extend from Cape Cod northward; the American, from
Cape Cod to Cape Hatteras; the West Indian, from Cape Hatte-
ras southward. On the Pacific coast the divisions, without defi-
nite 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 com-
prises 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.

VI

SOME BOTANICAL FACTS ABOUT ALG

HE 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 alge.

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. Algez 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 alge are microscopic in size, each indi-
vidual 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 alge which consist
of a single cell. This plant or cell divides, and the separate divi-
sions 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 Pro-
tococcus nivalis, or red snow, described on page 33, is a closely

allied species. The green and blue-green scums and slimes on
25

26 INTRODUCTION

brackish ditches and on the stones and woodwork of wharves are
also species of the lowest orders of algze 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 Confervacec, form a large
part of the green vegetation between tide-marks.

The vegetative body of a thallophyte is a thallus, and corre-
sponds to stem and leaf. It is also called a frond. What
corresponds to the root of flowering plants is in alge a disk or
conical expansion of the base of the plant. It is simply a hold-
fast by which the frond attaches itself to any submerged material.
The algw which grow on sandy shores and on corals have hold-
fasts which branch like fibrous roots and penetrate porous sub-
stances in all directions; but this is only for greater stability,
and is an adaptation to the habitat. Holdfasts do nothing for
alge other than the name implies, whereas real roots absorb the
nourishment upon which plants live. Algee are nourished by the
substances held in solution by the water which surrounds them.

Algee 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 alge 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 re-
semble plants which have leaf and stem. The botanical distinc-
tion 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 hori-
zontal 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 Monos-
troma a double layer is opened or torn apart, giving a frond with
a single layer of cells.

SOME BOTANICAL FACTS ABOUT ALGA 27

The stem-like forms of certain algee 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 alge in the differentiation of parts, or
vegetative forms, are to be found in the Fucacee, 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 repro-
duction. 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 alge are annuals; a few are perennials, and cast off and
renew their lamine 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.

VII
NAMING OF PLANTS

HE 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 desig-
nating character as John or James
This is called the binomial (two-name) nomenclature. It was
introduced by Linneus, 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 Alge are:

Cyanophycee (subclass of blue-green alge).

Chlorophycee (subclass of grass-green algz).

Phoophycew (subclass of dusky-brown or olive-green alges).

Rhodophycee or Floridee (subclass of red algee).

Orders are, with few exceptions, the names of genera with the
termination -acew, as:

Ulwacee, from the genus Ulva.

Ectocarpacew, from the genus Ectocarpus,

Gigartinacee, from the genus Gigartina.
28

NAMING OF PLANTS 29

Suborders, or groups between orders and genera, terminate in
-ee. Names of genera are nouns or words taken as nouns. They
are derived from any source,—from prominent or peculiar char-
acteristics, 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 -ti. 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 alge 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 sea-
weeds 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, ete.), in the classification of both animals and plants, is
indicated by a special kind of type.

Vill
DISTRIBUTION OF ALGA

HE eastern coast of North America has been divided into

four sections, which correspond to the distribution of the
alges 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 sub-
mergence 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.
30

DISTRIBUTION OF ALG 31

The laminarian zone extends from low-water mark to the depth
of fifteen fathoms. The Laminariacee and the beautiful red alge
(Floridece) grow here.

The third or coralline zone extends to the depth of about fifty
fathoms. The alge 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, algze 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
alge 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. Sea-
weeds 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 alge 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. ’

IX

SOME PECULIAR AND INTERESTING
VARIETIES OF ALGAL

HE 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, con-
sisting simply of the first vegetable element, the cell, have, not-
withstanding 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 tor
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 ALG

Among the smallest alge 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 sili-
cious, shell-like covering, which divides and subdivides in their
reproductive growth, forming varied shapes which are exceed-
ingly 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

32 .

SOME PECULIAR VARIETIES OF ALG 33

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. Tri-
chodesmium 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 moun-
tains 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. Ata
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 Atlan-
tic, called the Sargasso Sea, he sails into a vast undulating marine
3

vx aad aauvyveruvsavar

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 navi-
gation, and, seen from a little distance, seem substantial enough
to walk upon. At other times, according to seasons and condi-
tions 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
Fucacee, 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 con-
tinued 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 scien-
tists. The physicist finds there the phenomenon of the ocean
currents holding in a vortex this immense mass of seaweed, the
zoologist 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.

According to one theory, the plants are dislodged by the tem-
pests 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

PLATE II.

Macrocystis pyrifera.

Nereocystis Liitkeana.

Agarum Turneri.

SOME PECULIAR VARIETIES OF ALG 35

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 Sargas-
sum, 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 buoy-
ancy enough to support the weight of its innumerable guests.
(Plate XVI.)

THE LAMINARIACEE

In the laminarian zone, described above, grow the Laminaria-
cee, 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 Liitkeana, 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 laminew 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 quar-

36 INTRODUCTION

ter of an inch, is reported by one author to be seven hundred feet
in length, by another fifteen hundre 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 leaf-
lets 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 lamine two or three feet long. The large stems from
which the lamine 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.

x
USES OF ALG

ATER covers two thirds of the surface of the earth, and
alge, 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. Alge 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 vege-
table food, thus keeping up the balance of life.

Fresh-water alge have a like economic value. The green sur-
face 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 (Spheoplea 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
37

38 INTRODUCTION

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.

Algze, 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 Laminariacew, 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 destruc-
tion 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 alge, 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
alga into another, the bulk of the latter would exceed that of the
former. The pelagic flora consists of Diatomacec, Protococcacee,
Peridiniew, 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 com-
merce. 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. Rho-
dymenia palmata (dulse) is an article of food in Ireland and Scot-

USES OF ALGA 39

land. 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.

XI
COLLECTING AT BAR HARBOR

HE 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 col-
lector. 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 alge; 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 crus-
taceous alga, Petrocelis cruenta. The water of the pool is of crys-

40

COLLECTING AT BAR HARBOR 41

tal clearness, and as one gazes into it one object after another
comes into view, until one is filled with astonishment at the num-
ber 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 Corailina
officinalis, which resembles coral, as the name indicates, are abun-
dant. This alga should be examined with a magnifying-glass.
It is covered with caleareous 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 Acmea testudinalis are also
to be found. A green crab (Carcinus menas) is snugly hidden in
a dark nook on the shady side of the pool, and many small crus-
taceans scuttle away from under stones as they are lifted. The
collector is always anxious for uncommon, or rather less plenti-
ful, species, and here are found two specimens of nudibranchs,
or naked mollusks, Aolis 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 expand-
ing their beautiful flower-like forms. It is useless to try to cap-
ture 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.

42 INTRODUCTION

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 en-
thusiastic 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 alge. Alaria esculenta, several feet in length,
is beaten to a fringe against the rocks, and Agarwm Turneri, the
sea-colander, is also found here, together with beautiful speci-
mens 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 de-
fense 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) olis and Dendronotus. Cling-
ing 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, indi- _

cates that this animal is undergoing transformation into a land
species. Lattorina 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, Acmea testudinalis, Buccinum undatum, Mya
arenaria, and Mytillus edulis.

COLLECTING AT BAR HARBOR 43

Under the rockweeds in small pools and crevices are the poly-
zoans 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 beauti-
ful 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 (Ophio-
pholis aculeata), sea-cucumbers (Pentacta frondosa), sea-anemones,
and crabs are abundant. If one lifts a stone the little crusta-
ceans 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 edu-
lis), 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 Potysiphonia fastigiata ;
other seaweeds,Rhedymenia-palmata, Chordarta-flageliforms, Des-
menestia——aculeata, Coretina—oficinatts, 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 alge are abundant. Even if not
collecting, it is well to carry a small tin pail to the beach and
float out pieces of the alge 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 they disclose curi-

44 INTRODUCTION

ous ana 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 (Hchinarachnius 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 (Cyania 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 tem-
porary 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 ALG .

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
(CYANOPHYCEA)

GRASS-GREEN SEAWEEDS
(CHLOROPHYCEZ)

47

TABLE SHOWING THE CLASSIFICATION OF THE BLUE-GREEN
SEAWEEDS DESCRIBED IN THIS CHAPTER

Class

ALG

Subclass
Cyanophycece
(Blue-Green Seaweeds)
Order Genera Species
Spirulina
Oscillaria

Calothrix pi
L. majuscula
Lyngbya { L. ferruginea

NOSTOCACEZ

48

BLUE-GREEN SEAWEEDS

HE minute alge, which form patches of purple color on
rocks, slimy layers or spots on wharves, bluish-green slime
on mud, emerald-green films on decaying alge, blue-green
slime on brackish ditches, and so on, are various species of the
subelass Cyanophycez. 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 power-
ful glass, and are not of special interest except to the botanist.

GENERA Oscillaria and Spirulina

The genus Oseillaria is so named from an oscillating move-
ment which these filamentous plants show when viewed under
the microscope. They are very delicate blue-green threads occur-
ring 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 move-
ment. Spirulina is often found growing with Oscillaria, and
forms purple patches on wharves.

Genus Calothria
( 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 alge 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-

4 49

50 MARINE ALGAE

green, 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 alge, and is often
found floating free. It is common in summer everywhere south of Cape
Cod and on the Pacific coast.

L. ferruginea or estuarti. 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.

TABLE SHOWING THE CLASSIFICATION OF THE GRASS-GREEN
SEAWEEDS DESCRIBED IN THIS CHAPTER

Class
ALG
Subclass
Chlorophycez
(Grass-Green Seaweeds)
Orders Genera Species
Ulothrix
C. melagonium
Chetomorpha { C. wrea
CONFERVACEE ¢ C. inum
C. arcta
Cladophora C. rupestris
C. gracilis
U. lactuca
Une U. latissima
E. clathrata -
ULVACEE E. compressa
| Enteromorpha B. intestinalis
E. lanceolata
\Monostroma
Group Siphonez
Chameedoris Cc. annulata
eee { Anadyomene A. flabellata
Acetabularia A. crenulata
DASYCLADACEE { Dasycladus D. occidentalis
Cymopolia C. barbata
P. dumentosus
Penicillus {p. capitatus
P. Phenix
U. flabellata
UDOTEACEE Udotea { U. conglutinata
A tuna
Halimeda { H. tridens
HH. opuntia
‘ i . plumosa
CODIACEE rh tc Cc. caneeiey males
C. prolifera
C. Mexicana
CAULERPACEX Caulerpa ‘2 plumosa
C. Wurdemanii

51

GRASS-GREEN SEAWEEDS

“WINHERE 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 alge 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 in-
habiting 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.” }

The grass-green seaweeds are more simple in structure, and
therefore are lower in order, than the red or brown alge. 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
algee 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 alga, 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 Ulvacee, 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.

1 Kerner.
52

GRASS-GREEN SEAWEEDS 53

In the green alge are found the extreme forms of one-celled
plants. In Plewrococcus the cell is microscopic in size. In the
Siphonee 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
(Confervacez), or of cells arranged in layers or flat surfaces, called
membranes (Ulvacez),

ORDER CONFERVACEZ

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 dif-
fers from Chetomorpha in the character of its filaments, which
are soft and gelatinous in Ulothria, but bristle-like and wiry in
Cheetomorpha.

Genus Chetomorpha

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. melagontum. 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
I

C. wrea. Yellowish-green, with filaments erect and less rigid than

54 MARINE ALG

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. mela-
gonium and C. erea, which have become detached from their holdfasts
and have continued to grow. (Plate III.)

GEenus Cladophora

(''‘Branch-bearing "')

Frond filiform, branched. There are many species of Cla-
dophora, 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 com-
mon 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.)

ORDER ULVACEZ

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 sur-
faces of no definite shape, sometimes are narrow and ribbon-like,
or they may be simple or branched tubes. When the membrane

PLATE III.

Cheetomorpha linum.

Chztomorpha melagonium.

Cladophora arcta.

Cladophora rupestris.

PLATE IV.

Cladophora gracilis. Ulva lanceolata.
Ulva lactuca, var. rigida. Enteromorpha clathrata.

GRASS-GREEN SEAWEEDS 55

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 En-
teromorpha. 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 Ulwa

Frond a thin, silky, flat membrane, sometimes leaf-like, again an
extended surface of no definite shape. These are the largest
green alge. 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 fiat, 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.

GEenus Enteromorpha

Fronds tubular, simple or branched, sometimes inflated. The
tubes vary in size in different species and also in the same spe-
cies, 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, tubulat, 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.)

56 MARINE ALG

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
sae-like at first, then breaks apart, leaving a thin, semi-trans-
parent membrane of no definite shape.

GROUP SIPHONEZ

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 inecrustation, from inter-
lacing, and from cohering on the edges.

ORDER VALONIACEZ:

The algee 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 Chamedoris

Cc. annulata. When young this alga consists of an annulated tube
formed of a single cell. The annular constrictions occur at short inter-
vals, 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.

PLATE V.

Enteromorpha compressa. Enteromorpha intestinalis.
Enteromorpha intestinalis. Anadyomene flabellata.

58 MARINE ALG

ORDER UDOTEACE

Genus Penicillus
The merman’s shaving-brush, characteristic of coral reefs.

P. dumentosus. UHoldfast 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 car-
bonate 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. Phenix. 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 laming. 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 ime. 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 fila-
ments, 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, resem-
bling 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.

Hi. 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.)

PLATE VII.

Halimeda tuna. Halimeda tridens.
Bryopsis plumosa. Codium tomentosum.

PLATE VIII.

Caulerpa Mexicana. Caulerpa Wurdemanii.
Caulerpa plumaris. Caulerpa paspaloides.

GRASS-GREEN SEAWEEDS 59

Hi. 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 CODIACEA

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 pin-
nules 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 color-
ing-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, com-
posed 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 CAULERPACEE

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

60 MARINE ALGAi

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 tropi-
cal waters, extending over large surfaces, and are the chief food
of turtles. (Plate VIIL)

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 lamine spring from the surface or from
the edge or base of the different leaf-like portions. Lamine 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
(PHAOPHYCER)

TABLE SHOWING THE CLASSIFICATION OF THE OLIVE-GREEN
AND BROWN SEAWEEDS DESCRIBED IN THIS CHAPTER

Class
ALGAE
Subclass
Pheophycez
(Olive-Green and Brown Seaweeds)
Orders Genera Species
E. littoralis
E. siliculosus
ECTOCARPACEE {soon EB. viridia
E. tomentosus

S. cirrhosa
S. radicans
Cladostephus C. verticillatus

SPHACELARIACEE { SPR GCIERS

RALFSIACER Ralfsia

P. latifolia
{ P. tenuissima

Punctaria
ENCELIACEE P. plantaginea
Asperococcus A. echinatus
Phyllitis P. fascia
D. viridis
Desmarestia D. aculeata
DESMARESTIACER { { D. ligulata
Arthrocladia A. villosa
DICTYOSIPHONACER Dictyosiphon D. foeniculaceus
ELACHISTACEE Elachista
Chordaria C. flagelliformis
M. virescens
CHORDARIACER Mesogloa M. divaricata
Leathesia
Myrionema

62

OLIVE-GREEN AND BROWN SEAWEEDS 63

Orders

LAMINARIACEE

DICTYOTACEE

CUTLERIACEE

FUCACEE

Genera

Chorda
Alaria
Agarum

Laminaria

Macrocystis
Nereocystis
Lessonia
Thalassiophylum

Dictyota

Zonaria
Taonia
Padina
Haliseris

Cutleria

Himanthalia

Fucus

Ascophyllum
Phyllospora
Cystoseira
Halidrys

Sargassum

Species

C. filum

A, esculenta

A, Turneri

L. longicruris
{z. saccharina

L. digitata

D. fasciola

D. dichotoma

Z. lobata

T. atomaria

P. pavonia

HI. polypodioides

C. multifida

Hi lorea
F. vesiculosus
F:; serratus
F. furcatus
F. ceranoides
A, nodosum
P. Menziesit
C. expansa
1 osmunda
S. vulgare
{s Montagnei
S. bacciferum

OLIVE-GREEN AND BROWN
SEAWEEDS

HIS subclass contains some of the most remarkable of the
seaweeds. Itis 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 Laminariacee). It in-
cludes 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 ECTOCARPACEA

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 Hetocarpus, and grows abun-
dantly everywhere, appearing like large, fine, dull-green plumes. (Plate IX.)

64

OLIVE-GREEN AND BROWN SEAWEEDS 65

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 alge and on wharves.

E. viridis. Tufts a little more loose and expanding than in E. silicu-
losus; spores in pods at the base of the branches. (Plate IX.)

£. 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 F'ucus.

ORDER SPHACELARIACER

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 RALFSIACEE

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 ENCELIACEE

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
5

66 MARINE ALGAL

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 algee 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 DESMARESTIACER

(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 verdi-
gris-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.)

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

PLATE IX.

Ectocarpus littoralis. Ectocarpus viridis.
Cladostephus verticillatus. Asperococcus bullosus.

PLATE X.

Phyliitis fascia. Desmarestia viridis.
Desmarestia aculeata. Desmarestia ligulata,

OLIVE-GREEN AND BROWN SEAWEEDS 67

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; leaf-
lets 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 DICTYOSIPHONACEE

Genus Dictyosiphon

D. feeniculaceus. Fronds filiform, bristle-like, branching into deli-
eate, hair-like branches; yellowish-brown. It resembles Chordaria flagel-
liformis, but is much finer. (Plate XI.)

ORDER ELACHISTACEZ

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 micro-
scopist, but not to the collector.

ORDER CHORDARIACEZ
(“ Oord-like")

Genus Chordaria

C. flageliformis (‘ 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.)

68 MARINE ALGA

Genus Mesogla@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. Com-
mon from Cape Cod southward; abundant in Long Island Sound.
(Plate XI.)

GrEnus 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 algee 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 alge which grow on other plants and which appear
like dark spots, or, at first, like stains, on Ulva, Enteromorpha, and
small red alge. These spots, which to the naked eye appear
like decay, show, under the microscope, a jelly-like substance
full of beaded filaments.

ORDER LAMINARIACEA

The plants of this order have large and coarse fronds (some
attaining an immense size), with stems, branching root-like hold-
fasts, and expanded leaf-like laminee. 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 laminw are repro-
duced 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.

In the genus Chorda the fronds are cylindrical; in Agarum

PLATE XI.

Dictyosiphon fceniculaceus. Chordaria flagelliformis.
Mesoglea virescens. Mesogleea divaricata.

PLATE XU.

Chorda filam. Alaria esculenta.
Agarum Turneri. Laminaria saccharin.

OLIVE-GREEN AND BROWN SEAWEEDS 69

the lamin are perforated; in Alaria there are wing-like leaflets
below the lamine.

The Laminariacee and Fucacee are the seaweeds used in making
kelp. For this the alge are burned, and the ash is then separated
into its different mineral constituents and used for various manu-
facturing 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 alge and many zodphytes 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, fre-
quently 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 papille# 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.)

70 MARINE ALG

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 dry-
ing and become solid. (Plate XIII.)

For the genera Macrocystis, Nereocystis, Lessonia, and Thalas-
siophyllum, see the Introduction, pages 35, 36.

ORDER DICTYOTACEA
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.)

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

PLATE XIII.

Laminaria digitata. Dictyota dichotoma.
Taonia atomaria. Padina pavonia.

PLATE XIV.

Haliseris polypodioides. Cutleria multifida.
Fucus vesiculosus. -

OLIVE-GREEN AND BROWN SEAWEEDS 71

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 grada-
tion of color. ‘Found in tropical seas. (Plate XIII.)

Genus Padina

P. pavonia, the peacock’s-tail. Frond broadly fan-shaped; sub-
stance between membranaceous and leathery; powdery on the outer
surface ; deeply and variously cleft or entire; several lamine emanating
from a stalk-like base ; each lamina fan-shaped ; concentric lines numer-
ous; 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.

HI. polypodioides. Fronds flat, forked, notched on lower part; di-
visions about one quarter of an inch wide ; distinct midrib ; olive-green ;
grows in tufts. It is found in North and South Carolina, and is abun-
dant on the Florida Keys. (Plate XIV.)

ORDER CUTLERIACEE

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 FUCACEZ

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.

72 MARINE ALGAE

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 arrangément
of paraphyses, or threads, some of which hold spores, while
others protrude through a small opening in the outer mem.
brane. Conceptacles are peculiar to the order Fucacee. 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.)

PLATE XV.

Fucus serratus. Fucus ceranoides.
Ascophyllum nodosum.

PLATE XVI.

Phyllospora Menziesii. Halidrys osmunda.
Sargassum vulgare.

OLIVE-GREEN AND BROWN SEAWEEDS 73

F. serratus. Frond distinctly toothed or serrated along the margin;
midrib conspicuous through the main axis and forked brauchings; 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; recep-
tacles 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 lamine 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, and 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 ; sub-
stance 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

74 MARINE ALG

is a tropical and subtropical genus, and has one hundred and
fifty species. Two of these, 8. vulgare and S. Montagnet, 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 parts, and the receptacles are more elongated. From south of

ape 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.

Il

RED SEAWEEDS
(RHODOPHYCEAi orn FLORIDEA)

TABLE SHOWING THE CLASSIFICATION OF THE RED SEAWEEDS
DESCRIBED IN THIS CHAPTER

Class

ALGZ

Subclass

Rhodophycee or Florideze
(Red Seaweeds)

Orders Suborders Genera Species
NEMALIONACE
aiebaLaore pena N. multifidum
Liagora
CHETANGIEE Scinaia S. furcetlata
GELIDIEEZ Gelidium G. corneum
GIGARTINACER
Chondrus C. crispus
G. mamillosa
: . G. radula
Gigartina G. spinosa
G. microphylla
P. membranifolia
Phyllophora { P. Brodivi
Sternogramme S. interrupta
Gymnogongrus G. Norvegicus
Ahnfeldtia A. plicata
3 C. variegata
Callophytlis { C. laciniata
Tridea

76

Orders Suborders

RHODOPHYLLIDEEZ

RHODYMENIACEE,
SPHEROCOCCER {

RHODYMENIEZ

DELESSERIEE ¢

\

RHODOMELEX

RED SEAWEEDS

Genera

Cystoclonium

Euthora
Rhodophyllis

Rhabdonia

Eucheuma

Gracilaria
Hypnea
Rhodymenia
Lomentaria
Champia
Chylocladia
Plocamium

Nitophyllum
Grinnellia

Delesseria

Polysiphonia

Laurencia
Dasya
Bostrychia

Rhodomela

Chondria

77
Species

C. purpurascens
C. cirrhosa

E. cristata

R. veprecula

R. tenera

RR. Coulteri

E. isiforme

G. multipartita
H. musciformis
R. palmata

L. Baileyana
C. parvula

C. articulata

P. coccineum
N. laceratum

{ . Ruprechteanum
Lx antnctatuom
G. Americana

D. sinuosa
{ D. alata

D. Leprieurti
P. fastigiata
P. nigrescens
P. parasitica
P. dendroidea
P. Baileyi
P. Harveyi
P. Olneyi
P. fibritlosa
P. violacea
P. urceolata
Var. formosa
P. variegata
P. Woodti
L. pinnatifida
D. elegans
D. plumosa
B. rivularis
R. subfusca
R. Rochei

R. larix

R. floccosa

C. dasyphytla
C. tenuissima
C. striolata

78 MARINE ALGAE

Orders Suborders Genera
Callithamnion
Griffithsia
Ptilota
CERAMIEE ( Syyridia
Ceramium
Microcladia
CRYPTONEMIACEE
GLOIOSIPHONIEZ Gloiosiphonia
Halymenia
GRATELOUPIEZ | Grateloupia
Prionitis
Pikea
DEMONTE ts iaisadeaon
RHIZOPHYLLIDEE Polyides
PReygssonnelia
SQUAMARIEE etrocelis
Hildenbrandtia
anarrieee sie
ALLIN Melobesia
BANGIACEE
Bangia
Porphyra

Species

C. americanunr
C. Pylaiseei
C. Baileyi
C. seirospermum
Cc. Necnoe oideum
occosum
Soto Bornetiana
P. serrata
P. elegans
P. densa
P. hypnoides
. filamentosa
C. rubrum
Var. proliferum
Var. secundatum
C. strictum
C. diaphanum
C. fastigiatum
C. tenuissimum
Var. patentissimum
M. Coulteri
ae borealis

G. capillaris

HH. ligulata
G. Cutleria
P. lanceolata
{ P. Andersonii
P. Californica
H ramentaceum

P. rotundus

P. Dubyi

P. cruenta -
HI. rosea

C. officinalis

B. fusco-purpurea
\ P. vulgaris
P. laciniata

RED SEAWEEDS

N Rhodophycez, known also as Floridee and Rhodospermez,

' alge 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, how-
ever, are not as large and do not as closely resemble stem and leaf
as do some species of the brown alge.

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 sea-
weeds. 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 re-
quired 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 siu-
gular in that they are incrusted with lime and resemble corals.

ORDER NEMALIONACEZ
SUBORDER HELMINTHOCLADIEE

Genus Nemalion
The threadweeds.

N. multifidum. Frond six to twelve inches long, cylindrical, solid,
cord-like, elastic, tough, shiny, very gelatinous; branches repeatedly in
79

80 MARINE ALG

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.

GEenus 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 CHETANGIEE

Genus Scinaia

S. furcellata. Frond cylindrical, one eighth of an inch in diameter,
tapering at base, sometimes constricted at intervals, regularly and sev-
eral 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
SviLy and on the California coast. It is not common. (Plate

SUBORDER GELIDIEE

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 alge
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 1s often difficult to distinguish on this
account. (Plate XVII.)

ORDER GIGARTINACEZ

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, accord-
ing to conditions of its habitation. In shallow tide-pools it is pale and

PLATE XVII.

Scinaia furcellata. Gelidium corneum.
Gelidium Coulteri. Chondrus crispus.

y!

PLATE XVIII.

Gigartina mamillosa. Gigartina radula.
Gigartina spinosa. Gigartina microphylla.

RED SEAWEEDS 81

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 leatheryin substance. It is an edible alga, and was formerly
very generally used for culinary purposes. At Hingham, Massachusetts
large quantities are gathered asan article of commerce. It isa 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.

G. mamillosa. Frond three to six inches high, one inch to two
inches broad, flat, leathery, gelatinous ; forking near the base, then divid-
ing 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 pro-
jections distinguish this genus from Chondrus, which it otherwise resem-
bles, 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; cov-
ered 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.)

. 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 lamine ;
lamin 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.
6

82 MARINE ALGA

P. membranifolia. Several stems rise from same disk; branches
expand into wedge-shaped, cleft or forked laminw; lobes bear on the
summit other lamin or leaflets divided in the same manner.

P. Brodici. Stem less branched and leaf-expansions broader and
larger than in P. membranifolia; lamine 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 hemi-
spheres. 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 seg-
ments 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 north-
ward, (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.)

Genus Irideca

Frond rises from stalk and widens into a flat, thick, leathery,
oval expansion, one to two feet long, and one to three inches broad ;

PLATE XIX.

Phylophora Brodizi.
Gymnogongrus Norvegicus,

Sternogramme interrupta.

Ahnfeldtia plicata.

PLATE XX.

Callophyllis variegata. Callophyllis laciniata.
Tridea. Cystoclonium cirrhosa.

RED SEAWEEDS 83

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 RHODOPHYLLIDEZ

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 ex-
posed 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 com-
mon 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 mm abundance
north of Cape Cod. It differs from Delesseria alata in having no midrib
orveins. It growsin deep water on stones, shells, andalge. (Plate XX1.)

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 cov-

ered with leaflets which are in turn edged with minute branchlets; color
deep red. It is found on the northern New England coast. (Plate
XX.

Genus Rhabdonia
(‘A wand "’)

R.tenera. Frond six to eighteen inches long, cylindrical, fleshy,
translucent, juicy; irregularly and profusely branched, branches long-
est at the base, erect, tapering at both ends, numerous branchlets; some-
times the main stem runs through the plant, sometimes it is lost in the

84 MARINE ALG

branching; spore-masses sometimes form knotty bunches on the side of
branches. It resembles a large Cystoclonium purpurascens. It is charac-
teristic 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. eionitie This species is common on the Pacific coast, and dif-
fers from R. tenera in having a more pronounced leading stem, and
branches shorter and crowded at the top of the frond.

Genus Hucheuma

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. Abun-
dant at Key West.

ORDER RHODYMENIACEZ
SUBORDER SPHEROCOCCEER
Genus Gracilaria

G. multipartita (‘many times divided”). Frond four to twelve
inches long; starting from a short, cylmdrical 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 abun-
dant in Long Island Sound. In Florida and on the California coast there

ae ine varieties which may be mistaken for Rhodymenia. (Plate

Genus Hypnea

HI. 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.

PLATE XXI.

Euthora cristata. Rhodophyllis veprecula.
Rhabdonia tenera. Gracilaria multipartita.

PLATE XXII.

Rhodymenia palmata. Rhodymenia palmata.
Lomentaria Baileyana. Chylocladia articulata.

RED SEAWEEDS 85

SUBORDER RHODYMENIEE

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 algw below
low-water mark, and is common on the New England and California
coasts. This is an edible alga, and, like Chondrus erispus, 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 pinnule 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 plenti-
ful in California. (Plate XXIII.)

SUBORDER DELESSERIEE
Genus Nitophyllum

N. laceratum. Frond expands from narrow base and divides almost '
at once into long, narrow, strap-shaped segments; minute leaflets, show-

°

86 MARINE ALGAE

ing 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 Cali-
fornia 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. sinwosa. 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. Lepriewrii. 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.)

SUBORDER RHODOMELEE
The genera included in this suborder are easily distinguished
when in fruit by the spore-cases, or cystocarps, which appear

PLATE XXIII.

Champia parvula. Champia parvula, magnified.
Plocamium coccineum. Nitophyllum laceratum.

PLATE XXIV.

Nitophyllum Ruprechteanum. Nitophyllum punctatum.
Grinnellia americana. Delesseria sinuosa.

PLATE XXV.

Delesseria alata. Delesseria Leprieurii.
Polysiphonia fastigiata (on Ascophyllum). Polysiphonia parasitica.

PLATE XXVI.

Polysiphonia dendroidea, a piece magnified.
Polysiphonia Harveyi, a piece magnified.

Polysiphonia dendroidea.
Polysiphonia Harveyi.

RED SEAWEEDS 87

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 alge.

Genus Polysiphonia
(‘‘ Many tubes "’)

A filament of Polysiphonia appears, when seen under the mi-
croscope, 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 micro-
scope, 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 per-
ennial, 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 isa dense mass of rigid filaments branch-
ing 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 northward at all seasons, and is easily recognized by its
general form and place of growth. Egg-shaped cystocarps, or spore-
yoccur in the ends of the terminal filaments. (Plate XXV.)
. 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 X XVII.)

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

88 MARINE ALGAt

set at acute angles, givimg 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 algz, and is common in Long Island Sound and north-
ward. 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 spread-
ing; when in fruit covered with tiny balls or cystocarps; siphons four
in number. It iscommon 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 recog-
nize the species in the young plant; color light to dark brown; cysto-
carps 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
XXVIL.)

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 be-
coming 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.

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

Re et

PLATE XXVII.

Polysiphonia nigrescens. Polysiphonia fibrillosa.
Polysiphonia violacea. Polysiphonia Woodii.

PLATE XXVIII.

Laurencia pinnatifida. Dasya elegans.
Dasya plumosa. Dasya plumosa, magnified.

RED SEAWEEDS 89

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.
BP. 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 in-
see 7 le light brown. Found on the California coast. (Plate

Genus Laurencia ‘

L. pinnatifida. Frond flat, thick, leathery; main stem with oppo-
site, 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.)

GEenus 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 cylin-
drical, 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. Inspring it is a soft, fine, feathery, and beau-

90 MARINE ALG

tiful alga of a red-brown color. It is found washed ashore, or in deep
tide-pools, south of Cape Cod. (Plate XXIX.)

BR. 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.
lariz ; stem and branches flat and divided in one plane ; branches alter-
nate; ultimate branchlets somewhat incurved; color black. In fertile
plants the terminal branchlets are gathered in a mass. Found on the
California coast. (Plate X XIX.)

Genus Chondria
Plants of this genus are distinguished by having the ultimate

Be sien attenuated at the base.
C. dasyphylla. Frond four to eight inches high; general outline

pyramidal; branches alternate on main stem; stem and branches cov-
ered with short, club-shaped (blunt at top, attenuated at base) branch-
lets; 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
sender) and the branchlets taper at both ends instead of being club-
shaped.

. 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 CERAMIEE

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.

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

PLATE XXIXx.

Bostrychia rivularis. Rhodomela Rochei.
Rhodomela larix. Rhodomela floccosa.

PLATE XXX.

Callithamnion Pylaiswzi, a piece magnified.

Callithamnion americanum.

Chondria dasyphylla.
Callithamnion Pylaisei.

RED SEAWEEDS | 91

branches ; color rose-pink. It grows on wharves and on algz 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, XXX1I.)

C. Pylaisei. 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. Itis found in spring
on wharves and on alge from Boston northward. (Plate XXX.)

C. Baileyt. Fronds one inch to three inches long, with main stem as
thick asa 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. Com-
mon in summer from New York to Cape Cod.

C. setrospermum. Frond two to five inches high, pyramidal in out-
line; 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 com-
mon 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 dis-
tinguish the divisions. It grows on eel-grass and on alge 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.)

92 MARINE ALGA

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 pinnule, 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 pinnule alternating with smaller feather-like pinnule,
giving a dense edge to all parts of the frond. It is found on the Cali-
fornia coast. (Plate XX XIII.)

P. hypnoides. Fiat, cartilaginous main stem, much branched, and
all beset with pinnule. It differs from P. densain having the alternate
pinnule straight and club-shaped, instead of toothed and curved, and
the plant is not so dense and compact. Found on the California coast.
(Plate XX XIII.)

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 ap-
pearance; 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.

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-

PLATE XXXI.
Callithamnion americanum, a piece Callithamnion seirospermum.
magnified. Callithamnion floccosum.

Callithamnion byssoideum, var.
fastigiatum.

PLATE XXXII.

Griffithsia Bornetiana. Ptilota serrata.
Ptilota serrata, magnified. Ptilota elegans.

ye

ea

ra
ot ae

Ptilota hypnoides.
Spyridia filamentosa.

PLATE XXXIiI.

Ptilota hypnoides, magnified.

Ptilota densa.

PLATE XXXIV.

Ceramium rubrum, var. proliferum. Ceramium rubrum, top of frond magnified.
Ceramium diaphanum. Ceramium tenuissimum, var. patentissi-
mum.

RED SEAWEEDS 93

like layer of cells over the whole surface, which make the ring-like
bands on the filaments less conspicuous.

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 seeund.

C. strictum (“straight”). Brown or purplish-red filaments of hair-
like fineness, growing in tufts two to six inches high, branching in nar-
row 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 alge, 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 becom-
ing closer and narrower as they reach the top; the upper segments
about equal, giving a level top and regular outline in mounted speci-
mens ; 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 alge 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 dis-
tant 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. Itis 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 bear-
ing branchlets, also divided on one side only; color dark brown. It is
found on the northern Pacific coast. (Plate XXXV.)

94 MARINE ALG
ORDER CRYPTONEMIACEA

SUBORDER GLOIOSIPHONIEE

Genus Gloiosiphonia
(‘ Viseid 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 muchin drying. Thespeciesis easily recog-
nized 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 GRATELOUPIEE
Genus Halymenia

HI. ligutata. 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 Jridea. Found on the northern California coast.

Genus Prionitis

P. lanceolata. Frond narrow, fiat, 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.

SUBORDER DUMONTIER
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

sy

PLATE XXXV.

Microcladia Coulteri. Microcladia Coulteri, magnified.
Microcladia borealis. Prionitis lanceolata.

PLATE XXXVI.

Pikea Californica,
Polyides rotundus.

Prionitis Andersonii.
Halosaccion ramentaceum.

RED SEAWEEDS 95

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

HH. ramentaceum. Fronds brownish-purple, six to fourteen inches
long, coarse and cartilaginous, cylindrical, hollow, compressed, attenu-
ated 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 Eng-
land and northern California coasts. (Plate XXXVL.)

SUBORDER RHIZOPHYLLIDEE

Genus Polyides

P. rotundus. Frond three to six inches high, cylindrical, cartilagi-
nous, repeatedly forked, ends obtuse ; spore-masses form numerouslighter-
colored excrescences on the upper divisions of the frond 3 dark red.

Common from New York northward, in deep pools and washed ashore.
(Plate XXXVI.)

SUBORDER SQUAMARIEE

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. erwenta. Frond closely adherent, forming dark-purple velvety
patches of indefinite outline on rocks and stones. Common north of
Cape Cod.

Genus Hildenbrandtia

Hi. rosea. Forms continuous pink incrustations of considerable ex-
tent on stones and rocks at low-water mark. Common everywhere.

SUBORDER CORALLINEE

The genera of this suborder are characterized by a calcareous
or stony incrustation of the fronds, which gives them the appear-
ance of corals. Most of the species are tropical.

96 MARINE ALG

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 ex-
pands horizontally and resembles a lichen. It forms brown and
pink crusts on other algee and on rocks, stones, and shells.

ORDER BANGIACEZE
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 Ula. In
color it is purple of various shades. The species are named from
variations in the outline of the frond. They are found every-
where, 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
ie rete eens a) margin much waved; sometimes attached at

e center, often widely expanded and folded, sometimes deeply lobed.
(Plate XXXVIL) ; ae

P. laciniata. Differs from P. vulgaris in being divided into narrow
segments or into wavy, ribbon-like forms. (Plate XXXVIL.)

K,, PLATE XXXVII.

Corallina officinalis. Bangia fusco-purpurea.
Porphyra vulgaris. Porphyra laciniata.

Part IT
MARINE INVERTEBRATES

Bureau Nature Study,
CRANELL UNIVERSITY, lihaca, N.Y.

I

PORIFERA
(SPONGES)

TABLE SHOWING THE CLASSIFICATION OF THE SPONGES
DESCRIBED IN THIS CHAPTER
Phylum and Class

PORIFERA
Subclass
Calcarea
Order Families Genera Species
HETEROCELA 5 ee
rantia . ciliata
NIDE
Bae } Leucosolenia L. botryoides
Subclass
Non-Calcarea
CHONDROSPONGLE
Suberites S. compacta
SUBERITIDE ) Polymastia P. robusta
Cliona C. sulphurea
CORNACUSPONGIE rs
Esperiopsis . quatsinoensis
DESMACIDONIDE
Microciona M. prolifera
HETERORRHAPHIDE Tedania
HOMORRHAPHIDE Hatlichondria H. panicea
‘ : Cc. oculata
Chalinopsilla ; C. arbuscula
E. officinalis
Var. adriatica
Euspongia Var. mollissima
SPONGIDE Var. rotunda
Subfamily Var. dura
EUSPONGINE HI. equina
Var. cerebriformis
; Var. meandriformis
Hippospongia « Var. elastica
HY, canaliculata
Var. gossypina
Var. flabellum
SPONGIDE
Subfamily | miveinia HH. campana
STELOSPONGINE

100

SPONGES

HERE are many animals which consist of but one cell. These

are called Protozoa, and comprise the Infusoria and other mi-
croscopic organisms. The animals next higher in the scale are
Metazoa, or multicellular animals, and the first group of this sub-
division 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 indi-
viduals with cells of different kinds that performed functions
analogous to those of higher organisms.

The sponge, as commonly seen, is only the skeleton or frame-
work, so to speak, of the living animal. In its natural state it is
avery 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 diges-
tion, and some in reproduction.

The framework is secreted in the mesoderm, and in different

101

102 MARINE INVERTEBRATES

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 en-
tirely of exceedingly fine flexible
fibers of a horny substance called
spongin. In other species the
spongin is intermixed with spic-
ules 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.

The spicules have a great variety of shapes, being rod-like,
knobbed, three-pointed, six-pointed, anchor-like, ete., and are a
feature in the classification of sponges.

The sponge is traversed throughout by a canal system, con-
sisting of a series of tubes through which water circulates, carry-
ing air and food to the ani-
mal. 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 flagel-
late hairs, each hair having a
collar at its base. These
cells, called choanacytes, re-
semble independent animals
To illustrate choanocytes (Ch): sectio1. 0. a cal- of the Protozoa, known as

careous sponge. ct, ectoderm; Mes, mesoderm; .
Ny, calcareous spicule; Hiz, ovum. flagellete Infusoria or Choa-

Various forms of sponge-spicules.

SPONGES

noflagellata. They take in and
digest food and eject excre-
ment 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 thencé
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 com-
plex.

Sponges vary greatly in
shape, size, color, surface, rigid-
ity, canal systems, and skel-
eton. They are cake-shaped,
tubular, digitate, palmate, cup-
shaped, vase-shaped, cone-
shaped, spherical, hemispheri-
cal, pedunculate, etc., their
shapes depending upon wheth-
er their growth is uniform or
is excessive in a horizontal or
in a vertical direction. When
they grow evenly in both direc-
tions massive uniform shapes
arise. If lateral growth pre-
dominates, broad, low, and in-
crusting shapes result. When
there is an excess of vertical
growth the forms are digitate ;

~

103

Vy " | i.

Canal system of Sycon gelatinosum. Transverse
section through the wall of a cylinder (parallel
with the course of the canals), showing one in-
current 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 pas-
sage; PG, paragastric cavity; em, early embryo;
em’, late embryo. (The arrows indicate the course
of the water through the sponge.)

104 MARINE INVERTEBRATES

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 com-
pressed folds. Differences in rapidity of vertical growth make
undulations more or less marked, producing lobes and protuber-
ances. Sometimes narrow vertical growth is retarded and hori-
zontal 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 Calearea and Non-
Calearea. 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 Spongillide,
which live in fresh water), are inhabitants of the sea, and live at
various depths. The sponges of commerce belong to the Non-Cal-
carea 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 im-
portance, 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

SPONGES 105

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 practi-
cable. 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 con-
cealed 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

106 MARINE INVERTEBRATES

is bright sulphur-yellow in color, grows in irregular masses of
considerable size and fine texture, and has low wart-like promi-
nences. It lives on shells spreading over both surfaces, at first
forming little burrows, but eventually penetrating the shell in
every direction, honeyeombing 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 com-
mon in shallow water south of Cape Cod. (Plate XXXVIIL.)

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.

PLATE XXXVIII.

Halichondria panicea. Suberites compacta.
Hircinia campana. Esperiopsis quatsinoensis (found
on the sea-beaches of Alaska).

PLATE XXXIX.

Microciona prolifera. Chalinopsilla arbuscula.
Chalinopsilla imitans. Euspongia officinalis, var. tuba. Chalinopsilla oculata.

SPONGES 107

Genus Microciona

M. prolifera. When young this species forms bright-red incrustations
over shells and stones ; later it rises into irregular lobes and tubular prom-
inences. 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 erumb of
bread, and is found cast up on all beaches. (Plate XX XVIII.)

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.arbuscuta. 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. Itis found in shallow water from Cape Cod to North
Carolina, and is abundant in Long Island Sound. (Plate XXXIX.)

Genus Huspongia

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. £. 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 num-
ber 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,

108 MARINE INVERTEBRATES

and one or more large oscula occur on top. The color of the living
sponge is black. (Plates XX XIX, 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 motlissima, the Levant toilet-sponge. Gener-
ally 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 ex-
panded, with conical process on upper surface.

Genus Hippospongia

HH. equina. Some of the sponges of this species are massive, spheri-
eal, 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.

AI. 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.

HI. equina, variety meandriformis, the velvet sponge. The sur-

face 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.)

Hi. equina, variety elastica (variety agaricina, Hyatt), the yellow
sponge. This is the second grade of commercial sponge, corresponding
to the Zimocea 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.

HH. canaliculata. Massive, frondose; more or less horizontally
expanded; bears finger-like processes of varying development on the
upper surface.

Ai. canaliculata, variety gossypina, the sheepswool sponge. Thisis
the highest grade of the commercial bath-sponge. It is called “‘sheeps-
wool” because, perhaps, of its irregular shaggy surface. It is covered
with tufts, the larger oscula occupying the intervening depressions.

PLATE XL.

Euspongia officinalis, var. adriatica. Hippospongia equina, var. meandriformis.
Hippospongia canaliculata, Hippospongia equina, var. elastica.
var. gossypina. Euspongia officinalis.

SPONGES 109

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.)

HT. 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 .re on the upper
surface. The sides are fluted with deep furrows which contain the small
incurrent apertures.

Genus Hirecinia

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 XX XVIII.)

II

C@LENTERATA
(POLYPS)

Phylum
CEHLENTERATA

Classes

HYDROZOA
(Zobphytes, small Jellyfishes, and a few Corals)

SCYPHOZOA
(Large Jellyfishes)

ACTINOZOA

(Sea-anemones and most of the Stony Corals)

CTENOPHORA
(Comb-jellies)

CQILENTERATA

HE animals included in the phylum Celenterata were once all

called zodphytes, or animal plants, because of their resem-
blance to vegetable forms. The name Celenterata 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 every-
thing.”

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 con-
traction 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 dis-
8 7 113

114 MARINE INVERTEBRATES

tinct 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 sae, or digestive cavity, and
* out of the mouth into the water.
The animals are classed according as the
eggs are formed on all or on special par-
titions, those being of the highest order
Diagram of radiate structure. Where a limitation and constancy of func-

tion 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 com-
pleted 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 Coelenterata are divided into four classes: Hydrozoa, which
include the colonies of zodphytes which resemble seaweeds, the
small jellyfishes which are born of these colonies, and the mille-
pores, which are colonies of zodphytes which secrete a stony
instead of a horny skeleton, yet differ in some respects from other

CQELENTERATA 115

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.

TABLE SHOWING THE CLASSIFICATION OF THE HYDROZOA
DESCRIBED IN THIS CHAPTER

Class
HYDROZOA

Order LEPTOLINLE
(Branched colonies or shrub-like communities of hydroids ; some permanently fixed,
others liberate swimming-bells)
Suborders Divisions Genera and Species
Clava leptostyla
Hydractinia polyclina
Coryne mirabilis

Sarsia
ANTHOMEDUSE Eudendrium ramosum
(Zovids not covered by Tubularia indivisa
protective sheath ; um- TUBULARIANS T. Couthouyi
brella of medusee strong- (Without polyp-cups)
ly arched ; egg-sacs in Paryp. ha crocea
manubrium) Corymorpha pendula
Hybocodon prolifer
Pennaria tiarella
P. gibbosa
Bougainvilleasuperciliaris
Eucope diaphana
CAMPANULARIAN ° pa
wa = a 5 S < Oceania languiaa
‘olyp-cups stalked) : .
on Clytia poteriam

C. bicophora

Zobids covered with eup- Bs
: SERTULARIANS Sertularia pumila

like sheaths; umbrella
of meduse thin and not
very convex ; egg-sacs in

S. argentea

(Polyp-cups sessile) c
S. cupressina

| Obelia commissuralis

line of radial canals) PLUMULARIANS te ios
(Pilon Hinsenoincie if pele hai ee
of branches only) ( UMUALIA fe alcata
Family
GERYONOPSIDE Tima formosa
Family
EQUOREIDE Zygodactyla groenlandica

116

HYDROZOA 117

Order TRACHYLINE

(No fixed zophyte stage ; always free-swimming meduse)
Suborders Genera and Species

TRACHYMEDUSE
(Tentacles spring from
margin of umbrella; a
manubritim: longs go- Trachynema digitale
nads in connection with
radial canals)

NARCOMEDUSZE
(Tentacles spring from
midway between sum-
mit and margin of
umbrella; manubrium
short; gonads in con-
nection with manu-
brium)

Order HYDROCORALLINA
(Skeleton of carbonate of lime)

Millepora alcicornis
Order SIPHONOPHORA
(Pelagic free-swimming colonies ; exhibit extreme polymorphism of zo0ids)

Nanomia cara
Physalia arethusa
Vellela limbosa

TERMS USED IN DESCRIBING HYDROIDS

Cenosare (“common flesh”): The fleshy axis, or organized
living bond, by which the zodids are organically united to one
another. It consists of three layers: ectoderm, endoderm, and
mesoderm.

Ectoderm (“ outside skin”): The outside one of the three or-
ganized 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 zodid.

Hydranth (“water flower”): A nutritive zooid.

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 recep-
tacle 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.

Perisarce (“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.

Zooid (“animal form”): One of the animals which form the
colony.

118

CLASS HYDROZOA
SEAWEED-LIKE ZOOPHYTES AND SMALL JELLYFISHES

HE 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 liwing 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 zodids, or individuals of the community.
There is division of labor, as in other communities: some of the
zodids 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 (medusee).

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 zodids at their ends. There
is often more complex branching. The zodids in certain genera
(tubularians) are uncovered; in others (sertularians) they are
incased in a glassy, cup-like, horny sheath.

. Three kinds of zodids, polyps, or hydranths—as they are indis-

criminately called—are attached to the stem. Those having an
119

120 MARINE INVERTEBRATES

open end and a crown of tentacles are the nutritive individuals.
Small, club-like dilations are immature zodids. The blastostyles,
or reproductive zodids, are long, cylindrical, mouthless, and cov-
ered. At maturity the cover is ruptured, and the meduse 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 medusa, or jellyfishes, the convex side of each saucer, or
swimming-bell, is called the ex-wmbrella ; 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, extend-
ing 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 planule.
These are spherical bodies covered with cilia (hairs), by means of
which they swim about for a time; but they finally attach them-
selves 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 zodphyte stage beginning in the
autumn and the medusa stage in the spring.

Some meduse, besides reproducing by means of eggs, multiply
by budding, small meduse 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 zodids perish on the stem and have no medusa life, their
reproductive element giving rise to the hydroid’*form without
metamorphosis. The Zrachyline have no hydroid life, being
always free-swimming meduse; 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.

HYDROZOA 121

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 meduse; those
which live always in the medusa state, the eggs of the jellyfish
developing at once into other meduse; 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 ani-
mal 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 LEPTOLINIZ

The members of this order agree in all essential particulars
being branched colonies having two principal forms of zodids,
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 in-
close the zodid and be close to the stem (sessile), as in sertula-
rians; it may be on the end of a short stalk, as in campanula-
rians; or it may not reach above the base of the zodid, as in
tubularians. - The genera are based upon these differences in the
perisare.

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 cam-
panularians have an arborescent form and bell-shaped cups on
stalks; the sertularians have sessile cups; and the plumularians
have a feather-like form, with zodid-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

122 MARINE INVERTEBRATES

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 fre-
quently washed ashore, and in their tangled masses smaller
living species often may be found.

THE TUBULARIANS

This division is characterized by zodids borne on long, slender
stems which are sometimes simple and small, sometimes branch-
ing and eight to ten inches long. The zodid has two rows of
tentacles, the central one being sometimes on a kind of probos-
cis. The reproductive zodids are in bunches, sometimes below
the outer row of tentacles, sometimes between the two rows.
The perisare does not cover the zodid. In color they are com-
monly 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). Hach tube is surmounted by a zodid 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.)

Genus Hydractinia

H. polyclina. The soft, pinkish covering often seen on shells inhab-
ited 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 in-
vested 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-

.

PLATE XLI.

Clava leptostyla. Coryne mirabilis.
Tubularia indivisa. Eudendrium ramosum.
Hybocodon prolifer. Tubularia Couthouyi.

HYDROZOA 123

like network over a surface and develops at intervals
projecting points on which the zodids 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 planule,
which swim about for a while and then give rise to
other colonies. It is found from New Jersey north- colony of Coryne,
ward, and is very abundant in Long Island Sound. Aatutal, size,

Genus Coryn

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 zodids, 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.)

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 meduse are very plentiful in the spring and summer,
and swim rapidly in all directions near the surface of
the water.

Genus Tubutlaria

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 hasa proboscis covered with
tentacles, disposed in series, which grow successively
shorter, the last being merely papille. The medusa-buds
hang in clusters between the outer tentacles and the pro-
boscis. The animal grows in bunches of five to ten tubes,
which spring froma creeping, tangled stem. (Plate XLT.)

\ Genus Parypha
Sarsia, the free P. crocea. This is one of the most beautiful of the tubu-
medusa of Corye. larians, It has a large, drooping head on a stem three to

124 MARINE INVERTEBRATES

four inches long. It is bright red in color, and from the center of the
circle of tentacles the reproductive zodids 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 brack-
dk ish water, on the eastern coast as far

ANY. af south as Charleston, South Carolina.

;
eV : Corymorpha pendula. See Plate
no. XLII.
STN ae ‘Genus Hybocodon
1 2 5%

ane HI. prolifer. One of the largest
YY, x lat tubularians, somewhat resembling Pa-
{ rypha crocea. It is deep orange in color,
LZ AK and the head is erect on a long
Noy NG lg BX a stem. The reproductive zodids are in

C yw y Fy al a cluster in the center of a double row
iva en of tentacles, and resemble a basket of
i < iF ° fruit. It grows singly, or in groups of
.< Fey two or three, in shaded tide-pools, which
[ap A 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 swim-
ming-bells. (Plate XLI.)

Genus Pennaria

\ P. tiaretta. The branches are ar-
\y ranged alternately and at right angles
to a central stem or axis; they taper,
Pennaria tiarella; a branch, natural being shortest at the top and bottom of
size, the stem. The zodids 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 zodids have two rows of tentacles,
the upper ones on a small proboscis. From the lower part of the pro-
boscis 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.
ane tae A species similar to P. tiarella, found on the coast of
orida.

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 meduse which it liberates are found in great numbers
in the spring. The tiny swimming-bellsare nearly globular. The tenta-
cles 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

PLATE XLII.

Corymorpha pendula.

Clytia bicophora.

E XLII, A.

PLAT

sima.

15;

Obelia long:

Sertularia pumila.

Clytia poterium.

HYDROZOA 125

the eggs of the animal are produced. In its habits it is sluggish, often
remaining im one position for several days.

THE CAMPANULARIANS

The hydroids which have an open, bell-shaped cup at the ter-
mination of a short, stalk-like stem, or branchlet, are mostly
campanularians. This division embraces jellyfishes of different
families. Many meduse 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
fupe are constricted and again expanded at the apex, forming an urn-

ike top.

Genus Eucope

E. diaphana. This species is often abundant on the fronds of Lami-
naria 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 zodid-cup
similar in form to that of Obelia. The medusa which this hydroid liber-
ates 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 ia abundant. The species is found from Long Island Sound north-
ward.

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-

126 MARINE INVERTEBRATES

six 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 meduse 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 zodids 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
zo0ids 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 pre-
ceding, 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.

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 distin-
guished from the campanularians because its zodid-cups are close against
the stems (sessile) instead of on stalks or pedicels. The stem creeps

‘dq ‘MIX ALVvId "291 TSI BLIB[N}LIG

-auissatdny BLIn[ny.log

PLATE XLIII.

Plumularian hydroid. Aglaophemia struthioides.
Aglaophemia struthioides, magnified. Plumularia falcata.

HYDROZOA 127

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
zooid-eups which turn outward at the ends. The cups of the reproduc-
tive zodids are not sessile; they are much larger than those of the nutri-
tive 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 zodid-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 zodid-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 cen-
tral stem. In some species the stems are naked below and
resemble quills. The zodid-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 asmall ostrich-plume. The zodid-
cups are arranged in a single row on one side of each snort 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
ealled nematophores, and are supposed to be degenerate zooids. At inter-
vals a branch is replaced by a cylindrical body covered with nemato-
phores, and in these the generative zodids 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

128 MARINE INVERTEBRATES

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 zooid-cups are tubular and closely pressed against one
another, and are ranged in rows on one side of the branchlets; the aper-
tures of the cups are plain and oblique. (Plate XLIII.)

FAMILY GERYONOPSIDE

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 EZQUOREIDE

Genus Zygodactyla

Z. groenlandica. Medusa
seven to eleven inches in diam-
eter; 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.

| " Re

\"

Zygodactyla groenlandica.

ORDER TRACHYLINE

The Trachymeduse are characterized by their direct develop-
ment, the egg of the jellyfish producing a medusa and not a
hydroid colony.

Genus Trachynema

Y. 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 ten-
tacles are long and numerous, and are curled up when moving. The
manubrium is long and has four expansions at the mouth. Eight egg-

HYDROZOA 129

cases 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

The genus Millepora (“thou-
sand pores”), which is the type
of this order, is a colony of
animals, like other hydroids,
which secrete calcareous in-
stead 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 isa ax,
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.

Trachynema digitale.

Genus Millepora

M. alcicornis, elk-horn coral. This beautiful coral, which is abun-
dant 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 dactylozodids, with tentacles and
stinging-cells. These seem to be the guard-polyps of the community.
The cups occupied by the zodids 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 zodids. The living animal
occupies only the outer, open space. (Plate XLIV.)

9

130 MARINE INVERTEBRATES

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

N. cara. This species is found on the New England coast. The
members of the community are arranged along a hollow stem about three

Adult Nanomia cara,

inches long which opens into
every individual. At the top
of the stem is a sae, or float;
just below this is a group of
swimming-bells which have
no manubrium or mouth, and
whose sole function is to pro-
vide locomotion for the com-
munity; and below these are
three sets of zodids, each
having a triangular shield
and tentacles. The tentacles
are longer than the main stem.
One of these last groups con-
sists 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 pen-
dent 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 ten-
tacle 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

HYDROZOA 131

tubularian hydroids. These animals are pink in color and move
through the water with a graceful swaying motion.

Genus Physalia

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 Aol

N whi hs
a)
' WWYyy .

floats on the surface of the water. Its
color is bright blue, varying to rose. On _gpW\\uuw
the upper side of this air-vessel isa crest, or Sj

sail, and from the under side depend long
tentacles, or streamers. Some of these ten-
tacles are covered with stinging- or lasso-
cells ; some are the feeding zodids, with flask-
shaped bodies, and some, which look like
bunches of grapes, are the reproductive
zovids. 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 ordess
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 ? S
sets of appendages, also of unequal size, f
which are the nutritive organs of the com- &, i
munity. They are clustered together on a ‘
stem like the others. The appendages of Physatiaarethusa, Portuguese man-
the third kind are small, resemble bunches _°'¥#" 0n¢ ffth natural size.

of grapes, and are scattered among the nutritive hydra. These last
are the reproductive zodids of the community.

oblong pear-shaped bag, full of air, which oo“

\
Se
f

Kt

Genus Vellela

V. timbosa. This hydroid is abundant on the Florida coast. It has
a bright-blue, flattened, oblong, bladder-like float, four to five inches

132 MARINE INVERTEBRATES

long, which is divided into a number of concentric, communicating com-
partments. 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. Associ-
ated with Vellelais 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.

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)

Orders
STAUROMEDUSE

Suborders Genera Species
(Umbrella conical or
vase-shaped ; no ten-
taculocysts )

:
|

Lucernaria L. auricula

(Umbrella conical and
divided by transverse
constrictions; four
interradial tentacu-
locysts)

CUBOMEDUSE

(Umbrella four-sided,
cup-shaped; four per-
radial tentaculocysts)

Pericolpa P. quadrigata

Charybdea C.marsupialis

DISCOMEDUSE Aurelia A. flavidula

(Flattened, saucer-like

or disk-shaped um-
brella; radial tubes
branched ; eight ten-
taculocysts)

CONNOSTOME
(Very small; marginal
tentacles; short and
solid; mouth square
without arms)

SEMOSTOME
(Square mouth with

C. arctica
Cyanea { C. fulva

four long arms; tenta- C. versicolor

cles long and hollow)

Linerges L. mercurius
RHIZOSTOME Pelagia P. cyanella
(‘' Root-mouth ")
Mouth obliterated b: 5 3
a of oral oe Cassiopeia CC. frondosa

across it; tentacles ab-
sent)
133

CLASS SCYPHOZOA
THE LARGE JELLYFISHES

HERE is perhaps no marine animal which excites more wonder
T than the jellyfish. Its transparency, its graceful rhythmical
movements, its long streaming tentacles, the variety and eccen-
tricity of its form, and often of its color, attract attention, and
one naturally desires to know something of its life-history. Jelly-
fishes are also called meduse, because their long appendages sug-
gest the locks of the Gorgon ; acalephs, on account of their stinging
or nettle-like properties; and sun-jellies, sea-blubbers, etc., be-
cause 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, ete.; but the general
plan of the internal structure is the same in allspecies. In shape
they are compared to a mushroom. From the center of an um-
brella-like top falls a central organ like the stalk of a mushroom.
It is called the manubriwm 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
medusz), there is a horizontal shelf, called the velum, or veil, be-
cause it sometimes falls like a veil.

134

JELLYFISHES 135

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 ten-
taculocysts, 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 con-
cave surface of the umbrella is a muscular zone, or zone of con-
tractile tissue, by which the animal opens and shuts the umbrella
and gets its locomotive power. The gonads, which are con-
spicuous 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 stinying-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 pene-
trate 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 plana, 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. Hach of

136 MARINE INVERTEBRATES

these saucers is finally detached, and when liberated is called an
ephyrula, and becomes a jellyfish. Thus its cycle of life is com-
plete. 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 meduse 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 STAUROMEDUSE

(“ Cross-meduse "’)

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 aslight quadrangular projection
in the center of the bell-like expansion. The arm-like projections are mot-
tled 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 PEROMEDUSE

(‘' Maimed meduse’’)

Genus Pericolpa

P. quadrigata. Umbrella conical and divided by a horizontal con-
striction 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.

JELLYFISHES 137

ORDER CUBOMEDUSZ

(‘' Cube-meduscee”’)

Genus Charybdea

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
ebont two inches in height. It is not foundon the coasts of the United

ates.

ORDER DISCOMEDUSZA
(‘' Disk-medusce"’)

SUBORDER SEMOSTOME

Genus Aurelia

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 (¢entaculocyst) con-
taining 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 sur-
rounded by delicate membranes,
or oral arms, each arm being
a folded membrane tapering to
a point. The edges of tho mem-
branes 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 meduse
swim in shoals, and are common
everywhere in summer. They
may be said to be annual ani-
mals, for they make their ap-
pearance regularly as free- Aurelia favidula, about one fourth natural size.
swimming meduse 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

My f, , f \
WOR MY (HK) ANY:

4)

138 MARINE INVERTEBRATES

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 at-

tain the planulastage. After the spawning
period the meduse, 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 medusze
are frequently capsized by the air which ac-
cumulates in the empty egg-cavities, and,
floating helplessly on the surface, are at-
tacked and destroyed by swarms of small

crustaceans; thus their cycle of life is ter-

minated. It has been suggested that the Strobila of Aurelia flavidula.
destruction of the mothers, by being cast

upon the beaches in the autumnal gales, is a provision to set free the
planule in a position favorable to their existence ; for when liberated

Cyanea arctica, greatly reduced in size.

they fasten upon the rocks and sea-
weeds of the shore, where, during the
winter months, they develop into stro-
bile, which in turn free their saucer-
like disks early in April.

GENUS Cyanea

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 feetlong. The
disk is red, the margin white and scal-
loped. The tentacles, of different
colors, are covered with lasso- or sting-
ing-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

JELLYFISHES : 139

is usually solitary, seldom being seen in company with others. It is com-
mon on the New England coast, and is frequently found stranded on the
beach, where it in no way suggests the beautiful appearance it pre-
sents 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 north-
ward.

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 cur-
tains being the darkest part of
the animal. It is not as large as
C. arctica, and the lobes of the mar- : oo
gin are deeper and more rounded. Linvergesimenourtus chiro ple: eh,

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.

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 RHIZOSTOME

The Rhizostome, or root-mouth jellyfishes, are very remark-
able. They have no tentacles, but covering the end of the manu-
brium 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.

140

, MARINE INVERTEBRATES

Genus Cassiopeia

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, ly-
ing 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 ten-
tacles ; 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
bodiesisnot 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 alge. These
jellyfishes are common on the
Florida coast, huddled together
on the sands of the coral reefs.
(Plate XLIV.)

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)
Orders Genera Species
Metridium M. marginatum
ACTINIABIA ; 9
Rhodactinia R. davidsii
(The = sea-anemones. z
ingles noakeistn) Holocampa Hi. producta
Sagartia S. leucolena
Oculina
Astrea
ea oe Meandrina
e stone- or reef-cor- ; Mf . Py
als. Colonies ; skele- EEOPES Ds Cenenntys ee
ton calcareous) Madrepora {oe cervicornis
M. palmata
Astrangia A, danaé
ANTIPATHARIA

( The black corals)
Subclass
Alcyonaria or Halcyonoida

(Tentacles and mesenteries eight in number ; tentacles feathered, that_is, with uniform
branches)

ALCYONACEA Alcyonium A. palmatum

Tubipora
GORGONACEA
(The sea-fans and sea-
whips. Compound,
tree-like colonies, with
horny axis, branching
throughout)

PENNATULACEA

(Free, phosphorescent;

colonies, with horny
axis; polyps in lat-
eral branches)

Pennatula

141

CLASS ACTINOZOA
SEA-ANEMONES, REEF-CORALS, SEA-FANS, SEA-WHIPS, AND SEA-PENS

HE 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-build-
ing 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 haleyonoids, 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 zodids
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 havea 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

142

SEA-ANEMONES 143

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 con-
tinuous 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 corre-
spond 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 sum-
mit 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 col-
umn or body. Each tentacle is furnished with similar sets of
muscles. The animal is sensitive, and at the least alarm con-
tracts its body by means of these muscles, and quickly trans-
forms 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 (planule). After swimming about for a time these at-
tach 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 in-

144 MARINE INVERTEBRATES

erease 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 ex-
panded 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, Hdwardsia and
Cerianthus, swim about when young, and in the adult state burrow
in the sand or mud, leaving only their tentacles exposed. Bucid-
ium 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. Minyasis 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 col-
oring and beautiful in form as to attract attention if found in
the expanded state; otherwise they are easily overlooked.

Genus Metridiwm

M. marginatum. This is the most conspicuous and abundant sea-
anemone of the northeastern coast. It is common from New York

SEA-ANEMONES 145

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 exceed-
ingly 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 num-
bers 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.

10

146 MARINE INVERTEBRATES

ORDER MADREPORARIA

STONE- OR REEF-CORALS

The coral resembles the sea-anemone and is a polyp con-
structed 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 indi-
vidual polyps of a colony are alike. The home of each animal is
ealled 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 sub-
stance (ccenosare) of the zodids 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 Astrea the polyps are inclosed separately, but in Meandrina
fission is confined to the upper half of the polyps, so that a com-
plex 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 aleyonarians,
differ materially from the ordinary idea of corals, as their frame-
work 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 exceed-
ingly fragile lime structure, while the red coral, Corallina rubrum,

CORALS 147

the species so much used for ornamental purposes, has an exceed-
ingly 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 individ-
ually, 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 astreeans, 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 astreans come the
meandrinas and the porites. The former have elongated openings
which extend in waving furrows over the surface. The porites
resemble astreeans, 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 (Gor-
gonacea), 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. Twubipora, 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,

148 MARINE INVERTEBRATES

and the beautiful sea-pens are both highly colored and phos-
phorescent. 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 vege-
tables until comparatively recent times.

With few exceptions, corals do not grow in water below the
temperature of 68°, 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 be-
comes lateral, and then gives off another bud from its upper sur-
face, and so the stem lengthens. (Plate XLIV.)

Genus Astreea

The star-corals. The corals of this genus are hemispherical
masses covered with small star-shaped pits, or corallites. Although
the diameter of an astreea-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 succes-
sively opened until a line of them extends along acommon 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.)

PLATE XLIV.

Millepora alcicornis. Lucernaria auricula.
Cassiopeia frondosa. Astrea argus.
Oculina.

PLATE XLV.

Porites furcata and P. astreaoides. Diplora cerebriformis.
Madrepora cervicornis. Madrepora palmata.
Mycedium fragile.

CORALS 149

GEenus 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 ex-
amined 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 (ccenosare).
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 perfo-
rated 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 cer-
tain polyps and corallites increase in length, growing longitudi-
nally, 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 mad-
repores 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 con-
tinues 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.)

150 MARINE INVERTEBRATES

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 strictures 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. danaé. 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

In this subclass—the
actinoid corals—the pol-
yps are of two kinds.
The smaller are without
tentacles and are called
siphonozodids. The
larger have but eight
radial partitions and
eight tentacles. This
limitationof partsplaces
them in a higher rank
than the corals of the
first subclass. Another
characteristic of these
polyps is the presence
of symmetrical branch-
lets on the tentacles,
which give them a
feather-like appearance.
These corals are called
Alcyonium palmatum : A, entire colony ; B, spicules. haleyonoids.

CORALS 151

Some of them may easily be fancied to have been selected for
haleyons’ nests, as the name suggests—the sea-fans, for example.

ORDER ALCYONACEA

GENUS Aleyonium

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 at-
tractive in appearance, but not so when contracted. It is found in
abundance on the New England coast. An immense Alcyonium, Para-
gorgia 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

The organ-pipe coral. This genus, which is deep red in color
and very fragile, consists of many tubes slightly separated from

Tubipora, organ-pipe coral, natural size.

152 MARINE INVERTEBRATES

one another, but connected by horizontal platforms at short in-
tervals. 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 expan-
sion, which unites with the expansions of other polyps and be-
comes 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 sub-
stance spicules of carbonate of lime, making it a kind of caleare-
ous crust or bark. In dried specimens this becomes very brittle
and is easily broken from the horny axis. (Plates XLVI, XLVIL)

The sea-fant 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 some-

PLATE XLVI.

GORGONIAS.
Eugorgia aurantica. Muricea specifera.
Pterogorgia acerosa. Gorgonia anceps.

PLATE XLVI.

Leptogorgia rigida (a gorgonia). Eunicea lugubris (a gorgonia).
Gorgonia flabellum (a gorgonia). Leptogorgia Agassizii (a gorgonia).
Pennatula borealis and P. aculeata
(sea-pens).

wig goss

SEA-FANS AND SEA-PENS 153

what 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.

TABLE SHOWING THE CLASSIFICATION OF THE CTENOPHORA
DESCRIBED IN THIS CHAPTER

Orders
CYDIPPIDA

(Two tentacles, retractile into
sheaths)

LOBATA

(Numerous lateral tentacles
contained in a groove; body
compressed ; two large oral
lobes)

CESTIDA

(Ribbon-like form, from body
being extremely compressed
in the vertical plane)

BEROIDA

(No tentacles; mouth very
wide ; gullet occupies greater
part of body)

Class

CTENOPHORA

Genera

Pleurobrachia

Mnemiopsis

Cestum

Idyia

154

Species
P. rhododaciyla
B. septentrionalis

B. vitrea
M. Leidyit

[z alata

C. veneris

I. roseola
I. cyanthina

CLASS CTENOPHORA
COMB-JELLIES

HESE 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.

155

156 MARINE INVERTEBRATES

ORDER CYDIPPIDA

Genus Plewrobrachia

P. rhododactyla.
A transparent spher-
ical 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
isan 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

Pleurobrachia rhododactyla, in motion. rapidity 3 they take

graceful curves as the

animal moves rapidly through the water. Plewrobrachia has a pink tint,
and prismatic colors play over it from the vibrating cilia. Itisa beautiful
and interesting creature to watch. Found
along the shores of Massachusetts and Maine.

o
Ara?
: &
aff | TR
ORDER LOBATA v #-g_{\|\ fe Sr
Genus Bolina -

B. alata. Slightly oval in form; lower a
part of the body divided into two large lobes B \~6
which hang below the mouth. Four of the *\\ \ f.
swimming-plates are shorter than the other ¢\ LAN s
four and terminate in curious processes or : ar (eo

short appendages called auricles. Bolina is .
about two inches in length, and is very Pi oe ep Re ee ae
10, peck ; m, mouth; 1, au-

delicate, transparent, and phosphorescent. ricles ; v, digestive cavity ; 9, h, short

Its contractile power enables it to vary in rows of flappers; a, f, long rows of

outline to a considerable extent. It has a Toppers: b% t.% tubes winding in
e larger lobes; i, base of gullet.

slow undulating motion, and sometimes ayouthalf natural size.

carries its lobes uppermost and open. Usu-

ally found associated with Pleurobrachia from Massachusetts northward.

. septentrionalis. Found on the northern Pacific coast.
B, vitrea. A species found in Florida.

COMB-JELLIES 157

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. Cestwm 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 diffi-
cult to capture it uninjured. Its habitat is the Mediterranean Sea. It
may be seen among the zodlogical specimens in almost any museum.

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

Cestum veneris.

158

MARINE INVERTEBRATES

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

LO ACE

LPN)

‘a
(eH

Idyia roseola, half nat-
ural size: d, e, f, g, h, rows
of locomotive flappers.

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 fin-
ished 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 swal-
lowing animals as large as themselves.

I. cyanthina. This species, found on the north-

ern 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

Orders Genera
Planocera
POLYCLADIDA { Stylochopsis
Leptoplana
Planaria

Procerodes

TRUILED IDA Bdelloura

Fovia
RHABDOCELIDA
Class

TREMATODA

(External and internal parasites )
Class

CESTODA

(Internal parasites)
Class
NEMERTINEA

Tetrastemma
Nemertes

Meckelia

Cerebratulus
Cosmocephala
Polina

160

Species

P. nebulosa

S. littoralis

LL. folium

P. grisea

P. frequens
{ B. rustica

B. candida

F. Warrenti

T. arenicola
N. socialis
N. viridis
M. ingens
M. rosea
C. angulatus
C. ochracea
P. glutinosa

WORMS

Phylum

NEMATHELMINTHES

Orders Families

ERRANTIA
SYLLIDZ

APHRODITIDE

PHYLLODOCIDE

NEREIDE

NEPHTHYDIDE

EUNICIDE

GLYCERIDE
SEDENTARIA or TUBICOLA

SPIONIDE
CIRRATULIDE

TEREBELLID

Class

NEMATODA

Genus
Pontonema

Phylum

ANNULATA

Class

CHATOPODA

Subclass

Polycheta

Genera

Polynoé

Harmothoé
Aphrodite
Phyllodoce

Nereis

Nephthys

Marphysa
Diopatra
Arabella
Lumbriconereis

Glycera

Nerine
Cirratulus
Thelepsus
Amphitrite
Polycirrus
Cheetobranchus

{
{

161

Species
P. marinum

Species

P. squamata
P. sublevis

A. imbricata
A. aculeata
P. gracilis

N. virens

N. pelagica,
N. limbata

N. ingens

N. picta

M. sanguinea
D. cuprea

A, opalina

L. tenuis

G. americana
G. dibranchiata

N. agilis

N. coniocephala
C. grandis

T. cincinnatus
A, ornata

P. eximius

C. sanguineus

162 MARINE INVERTEBRATES

Orders Families Genera Species
AMPHICTENIDE Cistenides C. Gouldii
Clymenella C. torquata
MALDANIDE 1 Maldane M. elongata
ARENICOLIDE <Arenicola A, marina
SABELLIDE Sabella S.microphthalma
: Serpula S. dianthus
ace Venere S. borealis
Subclass
Oligocheta
(Mostly terrestrial or fresh-water forms)
Class
GEPHYREA
Sipunculus S. nudus
SEURCULOMDES Phascolosoma P. Gouldit
Class
HIRUDINEA

(Leeches )

WORMS

URROWING 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 ani-
mals, is found in abundance a class of animals commonly known
as “worms,” and generally regarded as repulsive creatures un-
worthy of attention.

To the biologist, however, worms are among the most interest-
ing 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 flat-
worms, 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
163

164 MARINE INVERTEBRATES

meaning “worm”; the prefixes Platy-, Nemat-, Troc-, meaning
“ flat,” “thread,” “ wheel,” respectively ; while Annulata, meaning
“yinged,” describes the segmented forms belonging to that
phylum.

There are vast numbers of parasitic worms, which live inter-
nally 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 loco-
motor organs, and so on, as the case may be, the host supply-
ing 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
iength 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, asin Annulata. They have no body-eavity,
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 branch-
ing 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

WORMS 165

and otocysts. The latter are sacs containing crystals of ecarbo-
nate 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 distrib-
uted, 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 con-
stantly 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 them-
selves, and often are of the same color, and therefore are so incon-
spicuous 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 sur-
facé, 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

166 MARINE INVERTEBRATES

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 ar-
range: | in irregular rows near the margin and in groups in front of the
tentac es, 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.

PLATE XLVIII.

Polyelad worm.
Worm-tubes of Diopatra.

WORMS , 167

Genus Planaria

_P. grisea. Oval or elliptical in form; anterior end truncate: poste-
rior end rounded; color yellow or gray, with a light stripe; two black
eyes surrounded with white; length one half to three quarters of an
ined; pea about one eighth of an inch. Found under stones between
ide-marks.

GEeNus 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.

Géinus 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 RHABDOCELIDA

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 tubu-

168 MARINE INVERTEBRATES

lar covering; others remain naked. All are covered with vibrat-
ing cilia, which is a universal feature of flatworms. In color
they may be white, yellow, green, red, purple, etc., and some-
times 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 ante-
rior end of the body, and has no connection with the alimen-
tary 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 pro-
boscis 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 consider-
able size. Cheetopod 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 indi-
gestible 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 be-
fore dying. One species, Lineus sanguineus, is capable, after being
broken in pieces, of regenerating each section into a perfect worm.

WORMS 169

The nemerteans are carnivorous, voracious, and often canniba-
listic. They will live for some time in confinement, losing, how-
ever, their bright color, and the smaller worms will gradually dis-
appear, 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

L. 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
ee 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 yel-
lowish 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.

170 MARINE INVERTEBRATES

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 alge.

PHYLUM NEMATHELMINTHES
ROUNDWORMS

The worms of this phylum have the general name of round-
worms, which distinguishes them from the flatworms of the pre-
ceding 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; con-
stantly 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.

WORMS 171

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 analo-
gies 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, swal-
lowing sand and mud for the sake of the organisms they con-
tain. They themselves are food for fishes, which devour them
in vast quantities, rooting them out of their burrows or cap-
turing them at night, at which time they swim about.

CLASS CHATOPODA
(‘' Bristle-footed”’)

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

vent.cirr Vs
A magnified parapodium of Nereis dumerilit: dors.
are usually horny, sometimes «ir’., dorsal cirrus; vent. cirr., ventral cirrus; 8, sete.

simple, sometimes divided into joints, and vary in shape in different
genera. The parapodia have, besides the bristles, a second set of

172 MARINE INVERTEBRATES

hair-like appendages, called cirri. These are sense-organs and also
have a respiratory function. The cirri too vary in shape in dif-
ferent genera. Generally they are hair-like, but sometimes con-
ical; again they are broadened into scales, as in the Aphroditide.

The body-cavity in cheetopod 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 sur-
faces. The alimentary canal runs through the body, but is con-
stricted 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 cheetopod 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 circu-
lation is effected, not by means of a heart, but by wave-like (peri-
saltic) contractions of the dorsal blood-vessel. The body is cylin-
drical, 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 gitls,
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 seg-
ments near the head, as in Tubicola; or they may be extended
over the whole dorsal surface.

SUBCLASS POLYCHATA
(“ Many-bristled")
The polychaete worms have one or twe well-developed parapodia,
or limbs, on each side of every segment of the body, and on each

WORMS 173

parapodium is a bunch of bristles, or chetw. 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 chete, 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 deing this the worm eats his way into the hole, swal-
lowing the mud and sand. He assimilates the organic or vege-
table matter the mud contains, and ejects the rest in cylindrical
coils, known as castings, which lie in heaps at the mouth of the bur-
row. By these castings they may be traced. Others secrete tubes.

The polychete 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 polychetes form
tubes (Hunicide), and some Sedentaria form no tubes.

Many polychetes are beautifully colored, some in vivid reds
and greens, with various markings; some are iridescent; some
are phosphorescent.

ORDER ERRANTIA

Carnivorous, free Polycheta, with protrusible pharynx armed
with a horny jaw. ‘They are active, fierce beasts of prey.”

FAMILY SYLLIDE

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 APHRODITIDE

The scale-bearing annelids. This family of worms is distin-
guished from all others by having scales on the back. The scales,
called elytra, are flattened dorsal cirri carried on the upper para-

174 MARINE INVERTEBRATES

podia, 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 Polynoé

The species of Polynoé 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
papille at the top. They are sluggish in movement
andarefound understonesandin 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 Polynoé 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; iri-

\ descent; last pair of scales more slender than the others ;
Polynoé squamate. length one and a quarter inches, breadth about one
quarter of aninch.

Genus Harmothoé

H. imbricata. Sixteen pairs of smooth scales; variable in color;
usually gray, speckled, or striped.

Genus Aphrodite

A. aculeata. This polychete, sometimes called the sea-mouse, is one
of the most beautiful of worms. It is brightly iridescent in color, from
its sete, which form a fur-like coating over the dorsal surface. It has
fifteen pairs of scales, but they are hidden by the numerous seta. 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.

WORMS 175

FAMILY PHYLLODOCIDE

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
twelveincheslong. The general
color is bright green and irides-
cent. Found in tide-pools. Speci-
mens 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 be-
comes a little stale, the worms of
this and otherfamilies make their
way to the sides of the dish, where
they secrete a colorless slime
which holds mud or any light _,A#lvot aca, natoral size; o nearopoda
matter that it may come in con- chete; 3, felting bristles of notopodium.
tact 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

P. gracilis. Three inches or more long and one sixteenth of an inch
wide; large proboscis, with twelve longitudinal rows of prominent pro-

Phyllodoce paretii.

176 MARINE INVERTEBRATES

jections 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 NEREIDE

Genus Nereis

Among the most common of the polychete 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 pro-
cesses called palps. The palps are more con-
spicuous 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 peristo-
mium, 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 bris-
tles and cirri. The last segment of the body is elongated, cylin-
drical, and without parapodia, but has on the end a pair of long
cirri, which give the appearance of a divided tail. Hach 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, longitu-

Head of Nereis pelagica.

WORMS 177

dinal muscles in four bands, and muscles to
move the parapodia. Breathing is carried on
over the whole surface of the body, and es-
pecially in parts of the lobes of the parapodia
called gills. Its sense-organs are eyes, palps,
tentacles, and cirri,

ala ty ty)

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, ete., 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 polychete worms, often
measuring eighteen inches or more in length.

N. pelagica. Found in abundance on the New England shore and
northern coasts under stones and on shelly bot-
toms. 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 ante-
rior 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.

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.

S)

Nereis pelagica. 1, male;
2, female.

FAMILY NEPHTHYDDE

In this family the worms have a long,
thick, flattish body, a section of which has
a quadrangular form. The lobes of the — Nereistimbata. Male, anterior

g . . : part of body, head and extended
parapodia are widely separated and fringed _ proboscis,
12

178 MARINE INVERTEBRATES

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 b.own; 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; branchiz between the dorsal
and ventral parapodia. Found burrowing in
all kinds of mud on the New England coast.

N. picta. More slender than N. ingens ; color
whitish, mottled with brown on the dorsal an-
terior 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 EUNICIDE

These are beautiful worms, having a red-
: dish-brown iridescent body, with bright-red
branching gills, which look like feathers,
along the back. They form parchment-like
= tubes.

Genus Marphysa

Nephthys ingens. Anterior part : ix] .
of body and extended proboscis; 2L. sanguinea. Length six inches or more;

ventral view. Enlarged. 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 appendagesare yellowish-
brown, specked with green. The body is flattened. From the fifth seg-
ment long, dull to bright red, much-branched gills, resembling plumes,

WORMS 179

extend nearly to the end of the worm. On the ventral side of the para-
podia are whitish tubercles with a dark spot in the middle. These
papille 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.)

Diopatra cuprea. Head and anterior part of body, showing part of the branchis;
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 bril-
liant, 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 GLYCERIDE
These worms are long and smooth, with numerous segments.
They taper at both ends. The head is small, conical, sharply
pointed, and has four ery small tentacles. The proboscis, or

i
y

180

MARINE INVERTEBRATES

pharynx, when protruded, is very large and long, and appears too
large for the worm. The proboscis has four hook-like jaws.

Glycera mec-
kelii, with
pharynx
everted.

These worms burrow rapidly and disappear almost
instantly into the mud or sand.

Genus Glycera

G. americana. Color red or purple; has branched
gills on upper side of parapodia. Found from South Caro-
lina 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 Hrrantia 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 dif-
ferent forms. They have hair-sete on a limited
number of segments only, varying with the species;
the remaining segments have uncini, or hooked comb-
like rows of sete, which are very small, but often
crowded in bunches. Uncini exist also on segments
having hair-sete. 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, ete. Some species secrete

WORMS 181

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 sPIONDE

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 ex-
treme 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 anda mem-
brane on the gills of the anterior segments; gills red; bristles long and
numerous.

FAMILY CIRRATULDE

Worms of this family have a cylindrical body, more or less atten-
uated at each end; segments similar throughout; many segments
with long, filamentous
cirri which act as gills ;
and a conical head. XE \ We
They live in burrows.

Genus Céirratulus

C. grandis. Four to
six inches long; head
acute; segments numer-
ous, short, and distinct ;
color dull yellow, or
orange, to brown, often
iridescent beneath; ven-
tral surface somewhat
flattened. Numerous
long, filamentous, red to ij ANZ a
orange-colored cirri ex- Ls “Ui eri ee \
tend nearly the whole —f) f it~ \ ov

S27

a r\ 0" E/|

length of the body and (‘co \
act as gills. It is com-
mon in sand and gravel
at low-water mark from Cirratulus grandis.

Cape Cod to New Jersey.

SS)

(

182 MARINE INVERTEBRATES

FAMILY TEREBELLIDE

The body is cylindrical and largest on the anterior end; there
are one to three pairs of more or less branched gills on the an-
terior end, and the ventral surface of the anterior segments is
thickened by glands which secrete mu-
cus for tube-building. These gland-
spaces are called shields.

Grnus Thelepsus

T. cineinnatus. Two to four inches
long; pale red; marked like lacework on
the back; gills have numerous unbranched
filaments arising separately in two trans-
verse rows; tubes thin, transparent, flexible,
and hung with foreign substances ; attached
along the whole length.

Genus Amphitrite

A.ornata. Twelve to fifteen inches
long; flesh-color, reddish, or brown; three
> pairs of red plume-like gills and numerous

Amphitrite ovnali 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, be-

ing 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,
Chetobranchus

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 extend-
ing in every direction and dis-
tended as the blood flows into
them. C. sanguineus has ten- Polycirrus eximius.

Cistenides Goulditi.

bright colors.

vauddy shores from New Jersey northward.

FAMILY MALDANIDE

The tubes of these animals are formed

WORMS 183

tacles 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 AMPHICTENIDE
Genus Cistenides

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. Thisis a common worm,
and its horn-shaped tubes are so plentiful as to attract
attention on sandy shores. They willrepay 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 spe-
cies easy to identify. The
worm is transparent; the
internal organs showing
through give it the various
It is found on sandy and

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 Clymenetla

C. torquata. Body long, composed of
twenty-two segments; the fifth segment has

a collar-like fold; the caudal extremity is ¢,

Clymenella torquata,

a, head and extended proboscis,
ont view; b, posterior end; ¢, en-

funnel-shaped and edged with papille ; both tire animal, side view, naturel size.

184 MARINE INVERTEBRATES

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 seg-
ments, sometimes brownish. Tt 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 ARENICOLIDE

Genus Arenicola

A. marina. Five to ten inches long; brownish-green; body cylin-
drical, thickest on the anterior end; anterior and posterior ends without
cheete ; twelve to thirteen pairs of branched red gills on the central seg-
ments. It makes burrows eighteen to twenty-four inches deep on sandy
southern shores, and can be traced by castings at the mouth of the bur-
row. Commonly known as “lugworm,” and used by fishermen for bait.

FAMILY SABELLIDE

In this family the gills arise from two semicircular bases form-
ing the crown; the second lobe of the anterior extremity is
reversed like a collar; the gill-filaments have secondary pro-
cesses, 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 SERPULIDE

This family forms white calcareous tubes. One of the dorsal
gill-filaments is flattened, forming an operculum, or cover, with

WORMS 185

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 congre-
gated 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, be-
longs with the annelid worms on account of their mode of devel-
opment, 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

186 MARINE INVERTEBRATES

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 form-
ing 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 papille
which turn backward and overlap like scales. The rest of the body is
divided into longitudinal furrows and circular markings, giving it the ap-
pearance 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 appear-
ance 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

(Exeretory op

Order

GYMNOLEMATA
( Circular lophophore)

Suborder
CYCLOSTOMATA

(Tubular caleareous
zoccia, with circu-
lar apertures devoid

of closing appara-
tus)

Suborder
CHEILOSTOMATA

(Calcareous or chiti-

nous zocecia, usu-
ally with opercula;
avicularia, vibrac-
ula, and ovicells
often present)

Class

POLYZOA

Subclass
Ectoprocta

ing outside lophoph

of tentacles; tentacles retractile)

Genera

ARTICULATA

(Erect branches divided: Crisia
at intervals by chitinous

joints)

INARTICULATA { Tubulipora

(Erect or adherent zoa- Diastopora
rium ; unjointed)
Aitea
Eucratea
Cc ‘
CELLULARINA ellularia
Caberea
(Flexible erect forms)
Bugula
FLUSTRINA
(Cells quadrate; front | Flustra

wall of zowecium mem-
branous or depressed,
and has ridge-like mar-

oH Escharella
ESCHARINA Mollia
Zi i holt lei-
aa wholly calci Cellepora
188

yphore; mouth in center of circle

Species

C. eburnea

T. flabetlaris
D. patina

4. anguinea
E. chelata
C. ternata
C. Ellisit
B. turrita

{B. Murrayana
B. flabellata

F.membranacea
M. pilosa

Membranipora| M. lineata

M. tenuis
E. variabilis
M. hyalina
C. scabra

{ C. ramulosa
C. pumicosa

MOLLUSCOIDA 189

Genera Species
Suborder m7 Esau
Peey - hirsutum
CTENOSTOMATA Alcyonidium + “4" nisnidum
(Horny or gelatinous zocecia, having pe shi
tooth-like processes which close the A. parasiticum
apertures when the tentacles are - ‘ V. dichotoma
Vesicularia
retracted) 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

TERMS USED IN DESCRIBING POLYZOA

Avicula’ria: Specifically modified zocecia, resembling a bird’s
head, found only in the Cheilostomata.

Brown bodies: Brown pigment-masses contained in the zo-
cecia 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 zocecium.

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 zocecium.

Vibra’ cula: A lashing filament, or specifically modified zocecia,

found only in the Cheilostomata.
Zoa’rium; The whole colony.
Zoc’cium: The body-wall of a single individual.

190

POLYZOA

MONG the numerous objects to be found on the beach at
low tide are the Polyzoa, of which there are said to be seven-
teen 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 alge 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 in-
crusting forms. Those having tree- or plant-like shapes resemble
seaweeds, while the colonies which spread over stones, shells, and
algze 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 be-
tween these colonies and those of the hydroids.

The Polyzoa are very numerous and form a most attractive
191

192 - MARINE INVERTEBRATES

am

group. They are plentiful everywhere, occurring between tide-
marks and at great depths on the floor of the sea. Rocks pro-
tected 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
alge, 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 marvel-
ous and orderly arrangement of the two layers of cells, or zoccia,
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 re-
sembling a bird’s head, with its bill constantly opening and shut-
ting. 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 alge. They have ex-
isted in vast numbers since early geologic times, and are plentiful
in the Tertiary deposits, known as Coralline Crags. Other erect
forms have a caleareous 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 flex-
ible, 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 calca-
reous substance, or of the two combined, as mentioned above.
This inclosing sheath is the exterior or cuticle of the animal and
is called the zowciwm, the whole colony being called the zoarium.
The animal substance within the zocecium 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

POLYZOA 193

the lophophore ; it is a contractile body, being, with the tentacles,
protruded from the zocecium or drawn within it at will) In
some species the orifices of the zocecia are surrounded with spines ;
others have lids, called opercula, which shut down when the poly-
pides are retracted. A singular modification of the zocecia 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 zocecium. 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 con-
stantly beat the water. In many of the zocecia 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 ab-
sorbs, or passes out, the brown body. The term of life of a sin-
gle polypide is not known, but in every colony many such trans-
formations are constantly taking place.

The colonies originally start from larvee produced in the ovi-
cells 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 zowcium. 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 GYMNOLEMATA
SUBORDER CYCLOSTOMATA

ERECT OR CREEPING POLYZOA

The zocecia are more or less cylindrical; the upper ends are

sometimes completely free and sometimes closely adherent. The
13

194 MARINE INVERTEBRATES

opening of the cell has no operculum. Ovicells, containing the
embryos, appear like pear-shaped swellings.

Genus Crisia

C. eburnea. This species is found in tide-pools on alge, especially
on the red seaweeds, growing in bushy tufts from one half of an inch to
an inch high. Caleareous, 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 north-
ward and on the Pacific coast.

Genus Tubulipora

T. flabellaris. This species is found attached to
slender branched alge, 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 Celle-
pora. (Plate XLIX.) :

Genus Diastopora

Crisia eburnea; a -D. patina. Tubular cells rise from a saucer-shaped
arch pearing evi’ disk about a quarter of an inch in diameter; cells lie
Sane eee obliquely or stand erect, and are crowded toward the

center; margin of disk without cells; colony white
and calcareous. Found on alge and eel-grass from Long Island

Sound northward.

SUBORDER CHEILOSTOMATA

In this suborder the zocecia 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 Altea

4. 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 algz, and is frequently found on Dasya, Griffithsia,
Plocamium, and eel-grass.

Tubulipora flabellaris. PLATE XLIX. Cellularia ternata.
1, Tubulipora flabellaris, natural size. Eucratea chelata. 1, Cellularia ternata, naturat size.

*‘poynisera ‘vyeppaqey “qd ‘G
Seyeypoqry “gq ‘Ff Spegiasem ATGSIq eau
‘sfToo May vw ‘eurkeuMyL “gq ‘gE | payrtesvar
vurdnumgpy “gq ‘(gf euedeamyy vpusng ‘T

“eYLLIN} Vpnsang

"Tl ALVId MISU[G Ba18qE,)

POLYZOA 195

GENUS Hucratea

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 ar-
ranged 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.)

Gxenus Bugula

B. turrita. This is a very abundant species, found everywhere along
the coast from Maine to North Carolina. Large quantities of it are

2 3

1, Bugula turrita, enlarged ; 2, the same, a branchlet, highly magnified ;
3, the same, a branchlet, bearing ovicells.

196 MARINE INVERTEBRATES

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 fork-
ing manner; the cells are arranged in four or five longitudinal LOWS,
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 coustantly 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, quad-
rangular, with a blunt, hollow spine at each angle. Many species have
simple horny tubes, closed on top, rising from some of the cells to the
height of half an inch. (Plate LI.)

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, Phyllo-
pora, Rhodymenia, and other alge.
The cells are membranaceous, with a
caleareous rim, and have one long
hair and several small ones surround-
ing the large roundish apertures. It is
found in abundance on the shores from
Long Island Sound to the Arctic Ocean.
c Foe . “ineata. Cells oblong, crowded,

OR ul closely adhererit ; slender spines on edge
os ae of aperture, which bend over and meet

, Membranipora pilosa; afew of the cells it: i ke d shells i
seen from above, magnified. 2, Membrani- across 1 > Incrusts roe S ana shelis 10
pora pilosa ; a single cell, seen in profile. broad, thin, radiating patches ; cells

PLATE LI.

Flustra foliacea. 1, Flustra membranacea; 2, 3, F. mem-
1, 2, Cellepora pumicosa, natural size; branacea, magnified.
3, C. pumicosa, magnified; 4, C. ramulosa. Vesicularia dichotoma.

POLYZOA 197

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 E’scharella

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 alge
in tide-pools.

Genus Cellepora

a scabra. It forms branching, coral-like masses on slender red
alge.

©. 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 alge. It ranges from Long Island Sound to Greenland.
(Plate LI.)

C. pumicosa. Cells urn-shaped, irregularly crowded together, form-
ing 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 Aleyontdium

A. ramosum. Twelve to fifteen inches high; much branched;
branches smooth, cylindricai, 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 papilla. These are the cells, or zocecia;
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.

198 MARINE INVERTEBRATES

A, hispidum. One of the most common species found inerusting
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 alge 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 clus-
ters 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 clus-
ters 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 oppo-
site branches; cells small and elliptical, arranged mostly in clusters.
Found creeping like a small dodder-plant over other polyzoans, hy-
droids, and seaweeds.

SUBCLASS ENTOPROCTA

Genus Pedicellina

P. americana. <A very small species. Club-like zocecia rise from
slender, white, creeping stems; tentacles roll up instead of retracting
into the cups. Found on hydroids, other polyzoans, and alge.

Vv
ECHINODERMATA

Phylum
ECHINODERMATA

Classes

ASTEROIDEA
( Starfishes)

OPHIUROIDEA

(Britile-stars)

ECHINOIDEA

(Sea-urchins)

HOLOTHUROIDEA

(Sea-cucumbers)

CRINOIDEA

(Feather-stars and Sea-lilies)

200

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.

Ampuil'le: Reservoirs or vesicles at the base of the fue 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 ambula-
cral 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 : Caleareous plates which cover the body and form the
exoskeleton.

Pedicella’rice: Small spines which have divided ends, like scis-
sors 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-vaseular system: A series of canals which conduct

water through the animal.
201

ECHINODERMATA

HE echinoderms, although their shapes are very unlike in

the different classes, have the same general internal struc-
ture, 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 echino-
derms is so unlike the mature animal that for a long time the
larvee 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-cucum-
bers (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 differ-

ently in the different classes. The movement of the animals is
202

ECHINODERMATA 203

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 caleareous
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 cireum-
oral 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 dis-
tends. 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.

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 alimen-
tary 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 fea-
tures in classification. They may be scattered
spicules of lime, separated plates joined by
connectirfy 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 holo-
thurians, after the manner of worms, take in sand and mud, deriv-
ing their nourishment from the organic particles contained in
them. All echinoderms live in the sea.

Aristotle’s lantern.

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 ;
pedicellarice sessile)

Families Genera Species
PORCELLANASTERIDE Ctenodiscus C. corniculatus
Astropecten A. articularis
Psilaster P. flore
ASTROPECTINIDE L. senegalensis
Inidia L. clathrata
L. alternata
PENTAGONASTERIDE Mediaster M. ceequatlis
ANTHENEIDE Hippasteria H. phrygiana
( Pentaceros } P. occidentalis
PENTACEROTIDE P. reticularis
" Nidoretla N. armata
ASTERINIDE Asterina ; A. folium
A, miniata
Order CRYPTOZONIA
(Ossicles crowded ; pedicellarice stalked)
Solaster S. endeca
SOLASTERIDE S. decemradiata
Crossaster C. papposus
ECHINASTERIDE ; oe C. sanguinolenta
Echinaster E. sentus
ae Heliaster H. multiradiata
A. vulgaris
ASTERIIDE Asterias A. Forbesii
A. ochracea
A. gigantea

204

CLASS ASTEROIDEA
THE STARFISHES

HESE 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 projec-
tions 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.

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 ampulle. These plates are called
the ambulacral ossicles. Numerous other ossicles extend over the
surface, buried in the integument of the body, making a caleare-
ous 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
pedicellarice, 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 andclean. The

pedicellarie are arranged, in some species, in circles around the
205

206 MARINE INVERTEBRATES

bases of the spines, and form groups over the dorsal surface.
Examining the backs of different starfishes with a strong magni-
fying-glass, one will be surprised to see the varied grouping of
the spines and pedicellaria. 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
dot 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
e by a branch with each
saadripecite, 6, Hone canel;e ragennaly4,retuleanaia, tube-foot, Ab the base of
ha ati daca each tube-foot there is a
globular reservoir, or ampulla. A valve connects the tube-foot and
ampulla. Whenthe 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 ampulle, a vacuum is formed, and the suckers are tightly at-
tached. 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 con-
forms 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 partic-

WN BY rg):

STARFISHES 207

ularly destructive to oyster-beds. The animal fastens itself to a
bivalve, and protrudes a part of its stomach, with which it envel-
ops 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 con-
ditions exist. Oystermen formerly were ignorant of the star-
fish’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 individ-
uals 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 Massachu-
setts 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

208 MARINE INVERTEBRATES

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 cut-
ting 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 ceca, whose function is
to secrete the digestive fluids. The much-folded stomach occu-
pies 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 fili-
form processes can in some large species be seen; these are the
dermal branchie, or breathing-organs, which may either project
through pores in the skin between the ossicles or be entirely re-
tracted. If the pyloric cwca be laid back, one can see the rib-
like arrangement of the ambulacral ossicles, and also the ampulle,
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 manip-
ulation.

ORDER PHANEROZONIA

FAMILY PORCELLANASTERIDE.
Genus Ctenodiscus (Plate LI)

C. corniculatus. Pentagonal; about two and a half inches in diam-
eter; the body flat, with wide marginal plates, giving a flat edge to the
rather long, pointed arms ; madreporic plate large; color greenish ; am-
bulacra 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 ASTROPECTINIDE

In this family there are only two rows of tube-feet; the rays
end in sharp points and have large ossicles on the margins.

STARFISHES 209

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 LIT.)

Genus Psilaster

P. flore. Diameter four to five inches; arms sharply pointed and
conspicuously bordered with large ossicles; body flat, with smooth sur-
face, 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; sur-
face 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 LI.)

L. alternata. Upper surface purplish, with irregular yellowish bands
on the arms; under surface yellow. Found in shallow water on the
Florida coast.

FAMILY PENTAGONASTERDE

Genus Mediaster

M. equalis. 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 ANTHENEDE

Genus Hippasteria

H. phrygiana. This beautiful starfish lives in deep water, but is
sometimes thrown up on the beach, and ranges from Cape Cod north-
14

210 MARINE INVERTEBRATES

ward. 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 pedicellariz are sessile and so
long and large as to be easily seen with the naked eye. (Plate LIT.)

FAMILY PENTACEROTIDE

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 curi-
osity-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 israised 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 LITI.)

FAMILY ASTERINIDE

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.

PLATE LII.

Ctenodiscus crispatus. Astropecten articularis.
Luidia clathrata. Hippasteria phrygiana.
Pentaceros reticularis.

PLATE LILI.

Nidorella armata. Asterina miniata.
Solaster decemradiata. Crossaster papposus.

STARFISHES 211

A. miniata. Pentagonal; somewhat raised in center j. about one
and a half inches across; edges sharp. Found on the California coast
close to shore. (Plate LIII.)

ORDER CRYPTOZONIA
FAMILY s0LASTERIDE

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
Meine; 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 ECHINASTERIDE

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 of 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.

212 MARINE INVERTEBRATES

FaMILy HELIASTERIDE

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 ASTERIDE

The Asteriide have the following characteristics : four rows
of tube-feet; ossicles small and unequal; spines isolated or
grouped; pedicellarie 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 cov-
ered with short spines, which are largest and thickest at the edges of the
rays, and surrounding them are the pedicellariz. The color varies from
pink, yellow, and brown to purple. :

A. Forbesii. The common starfish of the Atlantic coast, from Massa-
chusetts 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, espe-
cially 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 madreporie 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; diam-
eter two feet. Found on the California coast.

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)
Orders Genera Species
EURYALIDA
(Skin without plates; arms simple or Astrophyton A, Agassiziit
branched, and capable of being rolled
up)
Ophiopholis O. aculeata
Amphiura A. squamata
O. riiset
OPHIURIDA
Mae castirntal Ophiocoma O. ethiops
er eg ner: O. Alexandri
Ophiothrix O. angulata

213

CLASS OPHIUROIDEA

BRITTLE-STARS

HE 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 part-
way into them, while in ophiurans the body is a central disk, with
the five narrow arms attached to its margin. In form they sug-
gest 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 askin 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.
214

BRITTLE-STARS 215

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 radi-
ating 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. Asimilar or perhaps identical species occurs
on the North Pacifie 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 bor-
dered with granules. The arms are fringed with rows of thick, com-
pressed, obtuse spines, generally sixineachrow. The undersides 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

216 MARINE INVERTEBRATES

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 ina row. The color is gray or whitish,
sometimes marked with darker gray or brown. (Plate LV.)

Genus Ophiocoma

O. riisei, O. eethiops, 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. 0. riiset is
found at Key West, the other two species on the coast of Lower
California. (Plate LV.)

GENUS Ophiothria

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.) *

PLATE LV.

Astrophyton. ,Ophiopholis aculeata.
Ophiocoma oethiops. Ophiocoma Alexandri.
Ophiothrix angulata. Amphiura squamata.

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
Cidaris C. tribuloides
: F D. papillota
OIDARIDE Dorocidaris -
D. Blaket
Porocidaris P. sharreri
ARBACIADE { Arbacia A. punctulata
Coelopleurus C. floridanus
DIADEMATIDE Diadema D. setosum
Echinometra E. subangularis
S. drobachiensis
ECHINOMETRIDE Strongylocentrotus S. purpuratus
S. franciscanus
; Echinus E. gracilis
Es Toxopneustes T. variegatus
* Order CLYPEASTROIDEA
(Corona or shell a more or less flattened disk; anus excentric; lantern of Aristotle present)
SCHINAN TR ; Clypeaster C. ravenellii
Echinanthus E. rosaceus
Echinarachnius ; - P see -
SCUTELLIDE § CL COHCUS
Mellita M. testudinata
Encope E. michelini

Order SPATANGOIDEA or PETALOSTICHA
(Heart-shaped ; mouth and exeretory opening excentric; no lantern of Aristotle)

Moira M. atropos
Lovenia L. cordiformis
SPATANGOIDE Schizaster S. fragilis
Metalia M. pectoralis
Brissopsis B. lyrifera

217

CLASS ECHINOIDEA

SEA-URCHINS, CAKE-URCHINS, HEART-URCHINS

ORDER DESMOSTICHA
SEA-URCHINS

HE shell of a sea-urchin consists of many calcareous plates,
or ossicles, fitted closely together and forming a contin-
uous 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 am-
pulle (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 sur-
rounding 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
218

SEA-URCHINS 219

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 pedicellarie, 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

Test of sea-urchin, with the spines removed to show the arrangement of the
plates, lateral view: Amb, ambulacral zone with its perforated plates; 4p, apical
(aboral) pole; Int. amb., interambulacral zones. (From Bronn’s ‘' Thierreich.”)

of some of the pedicellariee 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 entan-
gled 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 spheridia, small globular bodies said to be
connected with perception.

The spines vary greatly in size, number, and form in different
species, and are such conspicuous features as to make the identi-
fication of species easy. In some the spines are solid and fluted;

220 MARINE INVERTEBRATES

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 Aris-
totle’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 larve, 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.

SEA-URCHINS 221

The Echinoidea present great differences in shape, being more
or less spherical, oval, discoid, and heart-shaped. These varia-
tions 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 gre-
garious, 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 turn-
ing round and round, and keep their cave, where they are fre-
quently 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 Strongylocen-
trotus 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 usedas slate-pencils by the missionaries in the
Pacific Islands.

222 MARINE INVERTEBRATES

FAMILY CIDARIDE
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 speciesis 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 LVI.)

FAMILY ARBACIADE
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 Celopleurus

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 DIADEMATIDE
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.)

| i i

coil i

PLATE LVI.

Pedicellarie of sea-urchins.
Spines of sea-urchins.

PLATE LVII.

Porocidaris sharreri. Dorocidaris Blakei.
Arbacia punctulata.
Diadema setosum. Strongylocentrotus franciscanus.

SEA-URCHINS 223

FAMILY ECHINOMETRDE
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 com-
mon species in, shallow waters of the northern temperate zones. It
extends as far as New Jersey on the Atlantic and to the State of Wash-
ington 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
algee, 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 wolf-
fish 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 pedicellarie 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 inlength. The tubercles on the naked shells are very promi-
nent, 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 ECHINIDE

In this family the ambulacral plates have but three pairs of
pores.

224 MARINE INVERTEBRATES

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 pro-
tected 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 (lunales). 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 ECHINANTHIDE

Genus Clypeaster

_ Cc. ravenellii. This species occurs in deep water from South Caro-
lina southward. The disk is about four inches in diameter, and is raised
in the center into a large cone. The ambulacra run down the sides of

CAKE-URCHINS 225

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 ¢olor is light yellowish-brown. (Plate LVIII.)

GENus Echinanthus

E. rosaceus. This is a large species, cblong 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 con-
spicuous 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 SCUTELLIDE

Genus Echinarachnius
THE SAND-DOLLARS

E. parma. Thisspecies, the shells
of which are very common objects pininarachni ineanna Ashes OnGe:
on sand-beaches from New Jersey “70” Snatter than natural sive
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.

E. excentricus. This is the common sand-dollar of the Pacific
coast. The disk, instead of being circular as in EZ. 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, form-
ing 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 lunales, 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’ lunale occurs in the interambulacral space

15

226 MARINE INVERTEBRATES

of the posterior end. The three anterior zones are shorter than the pos-
terior 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 LVIIL.)

GEenus Encope

E. michelini. Ambulacral zones unequal in size, the posterior pair
usually longer than the others; lunales 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 dif-
ferent in outline from the other orders of the class. The am-
bulacral 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 locomo-
tion; 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 sPATANGOIDE

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.

PLATE LVIII.

Clypeaster ravenellii. Mellita testudinata.
Eneope michelini. Test of Metalia pectoralis.
Lovenia cordiformis.

HEART-URCHINS 227

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, per-
haps, the largest species found, being six to eight inches long and pro-
portionately wide and thick. The shell is thin, more or less elliptical,
and densely clothed with long reddish-gray spines. (Plate LVI.)

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.

TABLE SHOWING THE CLASSIFICATION OF THE HOLOTHUROIDEA
DESCRIBED IN THIS CHAPTER

Class
HOLOTHUROIDEA
Orders Genera Species
ELASIPODA
(Deep-sea forms; tube-feet in
zones near together )
PEDATA Thyone T. briareus
( Well-developed tube-feet and false Pentacta P. frondosa
ambulacra) Lophothuria L. fabricii
S. tenuis
aes Suieca rn Synapta S. roseola
hc a | S. rotifera
Caudina C. arenata

228

CLASS HOLOTHUROIDEA

SEA-CUCUMBERS

§ hee holothurians, or sea-cucumbers, although in appearance
quite unlike starfishes and sea-urchins, have the character-
istic 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 madre-
poric 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 progress-
ing 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

(cloaca) at the other pole. The cloaca gives off a pair of much-
: 229

230 MARINE INVERTEBRATES

ger.op
BS 058
> rag 958 OSS

7t.bl.ves

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., in-
testinal 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.

SEA-CUCUMBERS 231

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.

The larve, 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 levigata 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 Téxas 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 papille.

232 MARINE INVERTEBRATES

Genus Pentacta

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 hour-
glass. When at rest the body is ovate
and somewhat pentagonal. On the an-
gles 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. Itis very plentiful on the Maine
coast in tide-pools and on the rocks at

Pentacta frond the sea-cucumber.

over the greater part of the
globe. The tough muscular
body is said to be edible, tasting
somewhat like lobster, or tre-
pang (Holothuria edulis), which
is found on coral reefs in Hast-
ern 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

L. fabricié (Verrill), Psolus fabricii
(Diiben), Cuvieria squamata (D. and
K.: Agassiz). The body in this species
is covered with rounded overlapping scales
and numerous granulations, and when it

low-water mark. The genus ranges

isretracted is about two and a half to three ropnoturia fabricii, showing under sur-

inches long and about one inch thick.

face with three rows of ambulacra.

SEA-CUCUMBERS 233
®

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 APOLDA
Genus Synapta

S. tenuis. This curious animal is long and slender, and so transpa-
rent that its internal organs are clearly visible. Around the mouth area
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 contrac-
tions. 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 speciesfound in Florida. It is light purplish in color,
and has eight or ten branches on each of the twelve tentacles. In this
pas 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.

234 MARINE INVERTEBRATES

Class
CRINOIDEA

Genera
Pentacrinus
Comatula

CLASS CRINOIDEA

FEATHER-STARS AND SEA-LILIES

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

The feather-star (Antedon), illustrating the Comatula form of crinoid,

CRINOIDS 235

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 Co-
matula, at a certain stage of de-
velopment, separates from the
stalk and swims freely about by
means of its arms. It can attach
itself temporarily by tubular pro-
cesses, which are developed on the
dorsal surface at the point where
the stem was attached. The ossi-
cles, or plates which cover the
dorsal surface, are free, making
the crinoid an animal of innu-
merable joints.

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 echino-
. derms, 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 nowremaining
only twelve of thétwo hundred genera whichexisted 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.

Pentacrinus asteria.

236 MARINE INVERTEBRATES

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)

Suborders Genera

EUPHYLLOPODA
(Phyllopoda of considerable
size, bearing ten to sixty
pairs of leaf-like swim-
ming-feet)

CLADOCERA
(Small phyllopoda; body
laterally compressed ; cara-
pace like a bivalve shell;
Sour to five pairs of swim- Daphnia
ming-feet ; chief organs of Leptodora
locomotion are the bdira- -
mous antenne; abdomen Moina
devoid of appendages. They Polyphemus
abound in fresh water, are
very prolific, and afford a
large amount of food to
Sresh-water fishes)
Order OSTRACODA

(Resemble minute bivalve shells ; swim by antenne ; body unsegmented ;
appendages seven pairs only)

Cypris (fresh-water)

Cypridina (marine)
238

ARTHROPODA 239

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)

Genera
Cyclops
Cetochilus
Sapphirina
Siphonostomata
Nicothoé

Order CIRRIPEDIA

CImperfectly segmented; fixed or parasitic during adult life; inclosed in skin
strengthened by calcareous plates; abdomen rudimentary;
appendages biramous, usually six pairs)

Species
LL. anatifera
Lepas L. striata
L. pectinata
B. balanoides
B. eburneus
Balanus B. rugosus
B. geniculatus
B. tintinnabulum

RHIZOCEPHALA ; Sacculina (parasitic on crabs)
(Parasitic) Peltogaster (parasitic on hermit-crabs)

Suborders Genera

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)

i Order SCHIZOPODA
(Small; transparent; shrimp-like; thorax more or less completely covered with soft
carapace; thoracic appendages biramous; eyes on stalks)

Mysis M. sternolepis
(Without gills or thoracic legs)
Euphausia

(With gills or thoracic legs)

240 MARINE INVERTEBRATES

Order DECAPODA

(Thoracic segments unite with head and form cephalothorax, which is covered by
carapace; eyes stalked ; maxillipeds have exopodites ; sive pairs

of walking-feet without exopodites )

Suborders

MACRURA
(Abdomen usually longer
than cephalothorax and
commonly extended ; ros-
trum usually prominent ;
eyes not inclosed in orbits ;
antenne and antennules
large; antennce have exo-

podites)
Genera
Penceus
Free-swimming Forms:
Shrimps and Prawns Paleemonetes
Crangon
Creeping Forms: Homarus
Lobsters and Crawfish Families ,
asTAcoIDz ) Panulirus
Scyllarus
Anomalous Forms:
Approaching the Brachyura
ANOMURA
DROMIDAZA Hippoconcha
Pagurus
PAGURIDA
Clibanarius
Pylopagurus
CENOBITIDZ Cenobita
HIPPIDA Hippa
Albunea
Porcellana
PORCELLANIDZ A
Petrolisthes
Lithodes
Echidnocerus
LITHODID :
(Fifth pair of feet foldea \ Acantholithodes
under the carapace) Cryptolithodes
Phyllolithodes

Species

P. setiferus

} P. brasiliensis
P. vulgaris
Cc. vulgaris

; C. franciscorum
HA. americanus
P. interruptus

; P. argus

A arcuata

P. bernhardus
P. pollicaris
P. longicarpus
C. vittatus

C. diogenes
HH. talpoida
} HT. analoga
A, gibbesit
P. sayana a
; P. sexspinosus
P. armatus
L.maia
; E. cibarius
EF. foriminatus
A, hispidus
C. sitchensis
P. papillosus

ARTHROPODA
Suborders
BRACHYURA
(Abdomen shorter than
cephalothorax, and perma-
nently folded under it; eyes
inelosed in orbits; anten-
nules and antenne small)
Families Genera
Carcinides
oe Callinectes
(Swimming crabs. Ov alip es
Cancer
CANCROIDZ
Menippe
Eupanopeus
Eurypanopeus
Neopanopeus
Rhithropanopeus
a GRAPSID 2a Hemigrapsus ;
eal
rs Pacygrapsus
s) Ocypoda
6 OCYPODIDA
g (Sand- and fiddler-crabs ) Uca
B Libinia ;
Hyas

MAIDA ( Loxorhynchus
(Spider-crabs) | Pugettia
Sternorhynchus
Epialtus
Pitho
\ Lambrus
CALAPPIDE Calappa
PINNOTHERIDZ Pinnotheres

Order STOMATOPODA

241

Species
C. menas
C. sapidus
O. ocellatus
C. irroratus
C. borealis
C. magister
C. productus
C. antennarius
M. mercenaria
E. herbstii
E. depressus
N. texana
R. harrisit
HA. nudus
HI. oregonensis
P. crassipes
O. arenaria
U. minax
U. pugnax
U. pugilator
LL dubia
L. emarginata
Hi coarctatus
AA, lyratus
HI, araneus
L. crispatus
P. gracilis
S. sagittarius
E. productus
P. aculeata
L. pourtalesti
Cc. flamma
P. ostreum

(Abdomen very large; second pair of thoracic legs very large; gills.borne

on abdominal segments)

Squilla
16

S. empusa

242 MARINE INVERTEBRATES

Order CUMACEA
(Small, shrimp-like)

Suborders Genera Species
Diastylis D. quadrispinosus

Order ARTHROSTRACA

(No carapace, as a rule; sia to seven pairs of walking-legs; eyes sessile)

Orchestia O. agilis
AMPHIPODA Talorchestia T. longicornis
(Body usually compressed Gammarus G. locusta
laterally) Chelura C. terebrans
Caprella C. geometrica
Cirolana C. concharum
Limnoria L. lignorum
Spheroma S. quadridentatum
I. marina
aporoD. I. ochotensis
(Body depressed or flattened) Idotea L. metallica
I. wosnesenskii
Chiridotea { Crees
C. entomon
Class
MERISTOMES
Order XIPHOSURA
Limulus L. polyphemus
Class

PANTOPODA (Lang)

Order PYCNOGONIDA
Phoxichilidium P. mavwillare

TERMS USED IN DESCRIBING CRUSTACEA

Abdomen: The posterior part of the body.
Antenne: 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 amphi-
pods 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 halfof the stomach, where food is ground.
Mandibles: The pair of appendages next behind the antenner.
Maxil'le: The first pair of appendages after the mandibles.
Mawxillipeds: The three pairs of appendages after the maxille.
Metame’res : Segments.
Orbits: Hye-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.
243

ARTHROPODA

HIS subdivision of the animal kingdom includes insects, cen-

tipedes, 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 recog-
nize 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 resem-
blance. 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 meta-
morphosis.

There are such modifications of these general features as the
habits of the different species demand. For instance, the appen-
dages 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
244

CRUSTACEANS 245

across the arms, and is said to reach even greater proportions.
Crustaceans live on land and sed, 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 free-
booters, 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 char-
acter 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 per-
form 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

246 MARINE INVERTEBRATES

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 charac-
ters 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 thoraz, 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 por-
tion of the animal is called the cephalothorax. Hach 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 antenne and are feelers. At the
base of the antenne are the green glands, said to have renal func-
tions. Both the antennules and the antenne 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 maz-
ille and the mawillipeds, 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, ete. The
food taken into the mouth passes into the stomach through a
short passage. The stomach is divided into two parts. The front

_CRUSTACEANS 247

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 intes-
tine which reaches the length of the body and opens to the out-
side on the under side of the telson, or last segment. A large
liver also pours its secretions into the intestine. The green sub-
stance 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 seg-
ment 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 acentral 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 mova-
ble stalks, which enable the creature to see in all directions and
from a higher plane than the body occupies. As arule, the eyes
occur in the head region, but in the shrimp Huphausia 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.

248 MARINE INVERTEBRATES

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.

The eggs, after being disvharged,
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.

Zoéa of Cancer irroratus, Last stage Some emerge with three pairs of legs,

before it changes to the megalops con» and are known as Nauplius; some are

Zoéa, having a carapace and abdominal

segments, butno abdominalappendages. Anotherstageis Megalops,

with large stalked eyes. Others are hatched as miniature adults.

These names were given when the embryo stage was not recog-
nized and the larvee were thought to be distinct species.

The growth of the animal is effected by moulting. The Crus-
tacea are named from the crust-like covering
which envelops them. Itis 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 — segatops stage of Cuncer
new one is formed beneath it. The old shell jrrerains. ais change
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

CRUSTACEANS 249

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 ac-
cidents, 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 com-
paratively 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 hav-
ing drawn a surface-net on some sheltered bay, it is difficult to have
an idea of the myriads of Hntomostraca 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

250 MARINE INVERTEBRATES

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 inter-
est, 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 para-
sitic 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 exter-
nal 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.

Nicothoé is found on the gills of lobsters. The truly parasitic
forms are usually very degenerate and lose the characteristics of
their order.

ORDER CIRRIPEDIA
C‘ 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 con-
stantly in motion, and create currents which carry food to the

BARNACLES 251

mouth of the animal, which is dependent upon such food as comes
within range of its tentacles.

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
m 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 antenne, which
HE have become suckers. It makes its hold

Balanus. A, external view: s, Secure by secreting a cement which
ee 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 be-
comes fixed until it at-
tains its adult form,
the barnacle fasts, liv-
ing 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
shellis permanent, and Balanus. B, anatomy : a, antennules; ad, adductor muscle ; m,
its successive stages PUT°tcutum, sr parapet; f orgum; wo, female aperture.
of growth are marked , ; ;
upon it by lines, as in mollusks. The lining of the shell, or en-
veloping skin of the animal, and also the cuticle of the legs are

252 MARINE INVERTEBRATES

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 zodlogists 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 every-
where 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

BARNACLES 253

the other that do fall upon the land do perish and come to no-
thing.” 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 maxille, 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. Thesé 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 circu-
latory organs are known; the cirripeds, or feet, are supposed to
perform these functions. They have also a food-canal, a diges-
tive gland, and excretory tubes. The eggs are carried under the
external fold of the skin in flat cakes.

LL. 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.

T. 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, start-
ing 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 preced-
ing species; lines of growth and radiating lines distinct; a decided line

254. MARINE INVERTEBRATES

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.

Lepas anatifera. A, the entire animal; B, anatomy. a, antennule; ¢, carina; cd,
cement-gland ; 1, digestive gland ; m, adductor muscle; od, oviduct ; ov, ovary ; p, ped-
uncle; s, scutum; ¢, tergum and testis; vd, vas deferens; h, tentacles.

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 Zepas, 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 con-
sisting 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

Different forms of Balanus. (After Darwin.) PLATE LIX. Cenobita diogencs.

BARNACLES 255

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 mem-
branous base, which does not form a solid plate like that of other
species.

PS. eburneus, the ivory barnacle. This species, like B. balanoides, is a
very common barnacle, and is found on all kinds of submerged wood-
work, whether fixed or floating. It is also found on the carapace of

256 MARINE INVERTEBRATES

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. erenatus. Shell white, cylindrical, some-
what 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; diam-
eter 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.

OPOSSUM-SHRIMPS 257

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 propor-
tionately 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.

Mysis sternolepis.

Genus Mysis

M. sternolepis. About one inch in length; translu-
cent; antennse 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 Decap-
oda have a similar anatomy, but are placed in two subdivisions

7

258: MARINE INVERTEBRATES

according to their external form. In Macrwra, the first subdivi-
sion, 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 antenne, or second pair of
appendages, are undivided, but are larger than the first pair, and
are often very long. At the base of the antenne are the renal
glands. Both the antennules and the antenne are slender, elon-
gated, 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.)

The next six pairs of appendages are grouped about the mouth.
They are the mandibles, the mazxillw, and the mavillipeds. The
mandibles are at the mouth-opening, and, being heavy and hard,
are adapted to tearing and grinding; they have a jointed attach-
ment, the palpus, whose office is to keep the mandibles clean.
The two pairs of maxillw 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 im-
mensely developed, as in lobsters. The claws are the chelw, and
the feet which bear the chele 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,

PLATE LX.

External Anatomy of a Lobster.

C, carapace; e, eye; g, gill; m, metastoma; n, endopodite; p, epipo-
dite; «, exopodite; I-VII, abdominal segments; 1, antennula; 2, an-
tenna; 3, mandibles; 4,5, maxille; 6, 7, 8, maxillipeds; 9, big pincer;
10-13, walking-feet.

SHRIMPS AND PRAWNS 259

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 ap-
pendages. The exopodite is present on the maxillipeds, but dis-
appears 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 cylin-
drical; 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 swim-
ming 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 caranace 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, antenne, and legs some-
times attain extraordinary length, and the chelz (claws) are not
always on the first pair of legs. In some species chele are on
two or three pairs of the legs. Above the antenne 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 1s not very well defined, the small individuals seeming to
be generally called shrimps, the larger full-grown ones prawns.

260 MARINE INVERTEBRATES

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 monopo-
lized by the Chinese.

Genus Penceus

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 antenne are a foot or more in length;
there are chelz 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, al-
though not so abundant, forms a part of the shrimp-supply in the fisher-
ies. 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 Palemonetes

P. vulgaris (Pale-
mon vulgaris). Aver-
age size one half of an
inch in length; body
translucent, almost color-
less, irregularly spotted ;
rostrum as long as cara-
pace and toothed on the
upper edge. It is found
: among eel-grassin brack-
ish water, and also in pools and ditches on muddy shores from
Massachusetts Bay to Florida. Commonly known as prawns.

Palemonetes vulgaris ; male.

GEenus Crangon

C. vulgaris, the common sand-shrimp. It ranges from Labrador to
North Carolina on the Atlantic coast and from Alaska to southern Cali-
fornia 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

PRAWNS 261

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. vul-

garis is broad at the anterior end and 7
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 antenne are long and have
plate-like antennal scales at the base,
which are fringed with hairs. The man-
dibles 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

Crangon vulgaris, the common sand-shrimp;
one hundred thousand dollars perannum. male natural size. :

CREEPING FORMS: LOBSTERS AND CRAWFISH

FAMILY ASTACOIDE

Genus Homarus

There are but three species of this genus, which is the most im-
portant one of all the Crustacea. They are H. vulgaris of Kurope,
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

262 MARINE INVERTEBRATES

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 chele,
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 remain-
ing two pairs. The appendages
on the abdomen are divided (bira-
mous). 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 pala-
table, 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 sim-

Homarus americanus, American lobster; male. lar 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.

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. :

LOBSTERS 263

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 zoée 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 at-
tended 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 chele 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- Me
lobster, or salt-water crawfish. It | ae
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 antenne 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.

P. argus or americanus resembles P. interruptus, and is found on
the coast of Florida.

Panulirus interruptus, the spiny or rock-lobster.

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 antenne are curiously modified
into broad, fiat, double plates reaching quite across the straight
anterior end of the carapace. The under scales of these modified
antenne 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

264 MARINE INVERTEBRATES

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 antenne makes them worthy
of examination when opportunity offers.

ANOMALOUS FORMS: ANOMURA

The anomalous forms which are intermediate between the sub-
orders 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 mem-
bers of the other divisions of the suborders, but there is a differ-
ence in anatomical structure which separates them in the classifi-

cation.
FaMILy DROME

Genus Hippoconcha

HI. arcuata. This curious little crab, found on the Florida coast,
earries the half of a bivalve shell over itsback. 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 PAGURIDE
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 mol-
lusk, 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

HERMIT-CRABS 265

well fitted to make the best of their surroundings, the body be-
coming 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 ab-
dominal appendages
are more or less
atrophied ; the sixth
pair become like
hooks, and _ these
fasten to the colu-
mella of the shell,
keeping the crab
securely attached to
it. In the female
some of the abdom-
inal appendages
are hair-like and are
adapted to carrying
the eggs. The tho-
rax, being protected,
is protruded from
the shell at will. é
Bho titsh ate OF Leth: ian loess eloiaioel voreas ay ast pao dneeeaager,
are much larger than rai to fasten to the columella of the shell in which the hermit
the others, and are :

provided with claws (chele). The first right foot is usually much
larger than the left, and, besides the usual functions of captur-
ing 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.

266 MARINE INVERTEBRATES

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 carcincecium, or house. It is interest-
ing 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 tradi-
tion, 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 care-
fully the empty shell, inserting his legs and feelers, and if he
decides to oecupy 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 itis 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

HERMIT-CRABS 267

with hermits. Adamsia palliata is always found on the shell oc-
eupied by Hupagurus 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 LE. kroyert.
This anemone in time absorbs the
shell of its host and itself becomes _,,4 Colony of sca-anemones (Ept

americanus) which had completely cov-
j pis ered and absorbed a shell occupied by a
its protector sa advantage to the hermit-crab (Eupagurus pubescens), which
hermit, who finds room in the yield-_ still lived within the cavity. The polyps
. . A 3 are not expanded.
ing 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.

th

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 north-
ward, and is replaced on the northern
California coast by P. alaskensis and P.
aleuticus.

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.

Pagurus bernhardus, the hermit-crab.

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

268 MARINE INVERTEBRATES

for any other hermit common on our coast, since it has the very distinc-
tive 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 ex-
posed to view. Another species lives in a shell covered with
polyzoans.

FAMILY CENOBITIDE

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 spe-
cies climbs the hills, but is more frequently met with in low, shaded,
marshy places. (Plate LIX.)

FAMILY HIPPIDE

Genus Hippa

Hi. 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 antenne are plume-like and about as

Hippa talpoida, the long as the carapace. Hippa lives on sandy beaches
sand-bug. 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

ANOMALOUS FORMS 269

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 Albuncwa

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 ap-
pear 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 ordi-
nary 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. <Albunea
does not extend as far north as Hippa, its range being from Georgia
southward. (Plate LXI.)

FAMILY PORCELLANIDE

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 de-
veloped, 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 dentic-
ulations on each anterior side; chele fringed with hair on the edges;
walking-legs somewhat hairy ; fifth pair of legs folded over base of cara-
pace; color reddish, with white spots. This species was once called occu-
lata, 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.)

270 MARINE INVERTEBRATES

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 quar-
ter of an inch; prominent and wide between the eyes; a small sharp
spine on each anterior side; chelipeds long; second jomt 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 LITHODIDE

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 sur-
face 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 atthe 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.)

Genus Hehidnocerus

E. cibarius. . This curious crab has the carapace raised in front into
a large cone-like elevation terminating in a long point. Three promi-
nent 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 poste-
rior 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,

PLATE LXI.
1, Hippa talpoida. 2, Albunza gibbesii.
3. 1, Porcellana sayana; 2, Petrolisthes armatus; 3, Petrolisthes sexspinosus.
4, Lithodes maia.

PLATE LAXII.

Echidnocerus cibarius. Cryptolithodes sitchensis.
Echidnocerus foriminatus. Phyllolithodes papillosus.

ANOMALOUS FORMS 271

spiny armature. The antenne 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 man-
ner 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, with-
out 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 atoad. This isa deep-water species, but itis,
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 spe-
cies 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, hasa high ridge
through the center of the anterior part, and the sides are broadly ex-
panded 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 inthe center. The lateral margins have
four prominent spines on each side, the two at the posterior ends being

272 MARINE INVERTEBRATES

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 refiexed. Crabs of this suborder inhabit all seas of the
globe, and are found from the shore to great depths. Some spe-
cies 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 respec-
tive modes of life. There is also great variation in their shapes
as well as in their color and markings. This diversity isso 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 innumber. The male has two pairs; the female has four
pairs, which it uses for carrying itseggs. The first pair of walk-
ing-legs are comparatively large, and end in chele, 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 exter-
nal or third pair of maxillipeds are broad and flat, and cover the
mouth-parts like a lid, or operculum.

CRABS 273

Crabs, like other crustaceans, are scavengers, living on dead ani-
mal 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 metamor-
phoses. The most marked forms are called the Zoéa and the Mega-
lops. 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 zoéa stage.
From this it changes directly to Megalops ; the Zoéa, seeming to be
attacked with violent convulsions, wriggles out of its skin a full
Megalops (page 248). The animal then has enormous eyes, an ex-
tended 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 consider-
able 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 sur-
face of the carapace is generally studded with tubercles, spines,
and stiff hairs of a peculiar character. This armature is for pro-
tective purposes, and is often used to secure foreign bodies, such
as alge, 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
18

274 MARINE INVERTEBRATES

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 rapid-
ity, notably the sand-erab, Ocypoda arenaria. Often when pur-
sued they will run into the surf instead of to their holes. The
common edible crab, Cullinectes sapidus, of the Atlantic coast, the
fiddler-crabs, and the spider-crabs are among the well-known
representatives of Brachywra.

FAMILY PORTUNIDE
SWIMMING CRABS
Genus Carcinides

C. meenas (M. J. Rathbun), Carcinws meenas (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, Buz-
zard’s Bay, and Long Island Sound. It is found between tide-marks, fre-
quently 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 anda
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,

Carcinides menas, the green crab.

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 enragé.

CRABS 275

GENus Callinectes

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.” Itis
found from Cape Cod to Florida, and after the lobster is the crustacean
which has the greatest commercial value, being taken in immense quan-

Callinectes sapidus, the blue crab.

tities 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 pro-
jects 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 chele are large and somewhat unequal in
size; then come three pairs of simple feet and a fifth pair, which are flat-
tened, 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 con-
vex above, and is covered with minute granulations, which are more nu-
merous over some portions than over others. The abdomen of the femaleis
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

276 MARINE INVERTEBRATES

erabs of this species are very active and can swim rapidly. They also
have the habit of pushing themselves backward into the mud for con-
cealment. 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

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, ard also is abundant on sandy
bottoms offshore. At low-water mark it buries itself up to the eyes
and antenn® in the sand, where it watches for prey and foes, and quickly

WIAA,

Ovalipes ocellatus, the lady-crab.

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 dis-
tinguished 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 sim-
ple in structure, ending in points. In color it is white, covered with
spotted rings of red and purple.

CRABS 277

WALKING CRABS
FAMILY CANCROIDE
Genus Cancer

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, hidingamong
rocks, nearly buried in
sand or gravel, and in
tide-pools, where some-
times amusing combats
between the males may
be seen. The carapace
is suboval, one third
broader than long, the
breadth being often from
three tofourinches. The
surface is granulated but :
smooth; the color is Cancer irroratus, the rock-crab; male.
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 — al-
though there seems to be
no reason for it — share
to any extent a place in
the markets with the blue
crab, Callinectes sapidus.

C. borealis, the Jonah
crab. This crab resem-
bles, and is frequently
taken for, C. wroratus.
It is larger than the latter
in full growth, and is
heavier and more mas-
sive. The carapace and
claws are rougher, the

Cancer borealis, the Jonah crab; male. 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

278 MARINE INVERTEBRATES

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 ex-
posed 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.

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 undu-

Cancer magister, the common crab of the Pacific coast; male.

lated and covered with papille, 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 yellow-
ish 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.

er antennarius, the California rock-crab.

Cane

280 MARINE INVERTEBRATES

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 chele are marbled with purplish
spots and are nearly smooth. The distinguishing features of this crab
are its large and hairy antenne, the hirsute margins of its abdomen and
walking-feet, and the numerous hairs on the under side of its body.

GENUS Menippe

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

ee Menippe mercenaria, the stone-crab ; male.

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 opera-
tion 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

MUD-CRABS 281

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 chele 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

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 com-
monly 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 flat-
tened above, and is smaller than Neo-

. Eurypanopeus depressus, the mud-crab ; male,
panopeus texana, which is somewhat hatiral ize.

convex above. The last two are com-

monly found together and have similar habits. Rhithropanopeus harrisit
lives near high-water mark and also in salt-marshes, and is comparatively
rare. The claws lack the dark tips of E. herbstit, and a distinct groove
follows the edge of the carapace.

FAMILY GRAPSIDE
Genus Hemigrapsus

H. nudus (Mary J. Rathbun), Heterograpsus nudus (Stimpson); H.
oregonensis (Mary J. Rathbun), Heterograpsus oregonensis (Stimp-
son). 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. Theanterior half of the side margins has two rather deep indenta-

282 MARINE INVERTEBRATES

tions, making two spine-like projections which bend forward. The
four posterior pairs of legs are more or less hairy; the chele 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 pro-
nounced 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 deseribed above, but is considerably larger,
and the carapace is banded with color.

FAMILY OCYPODIDE

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 Cancroide. 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 overthesand. Theyarealsodexterousin 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 chele
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.)

Genus Uca

U. minax (Gelasimus minax), U.pugnax (Gelasimus pugnax),
U. pugilator (Gelasimus pugilator), the fiddler-crabs. These species

Wiky %

PLATE LXIII.

Hemigrapsus nudus. Hyas araneus.
Ocypoda arenaria. Pugettia gracilis.
Libinia dubia. Pitho aculeata.

FIDDLER-CRABS 283

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, toge-
ther 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, be-
coming horizontal
below, with a cham-
ber atthe end. One
species, U. iminaz,
constructs an arch-
way over the mouth j
of its burrow, in Uca (Gelasimus) pugilator, the fiddler-crab; male.
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 ared patch at
the joints of the legs. It is a vegetarian in diet, living on small alge.
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. JU. 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. minaa, is a
vegetarian. U. pugnax is exceedingly abundant on muddy banks and
ditches of salt-marshes, the banks being sometimes completely honey-
combed and undermined by them. It ranges from Cape Cod to Florida.

284 MARINE INVERTEBRATES

FaMILy MAIIDE

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 along, 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 transplant-
ing, sometimes using sponges and polyps which are not destroyed
by being torn apart, and they also select their dress with refer-
ence to its masking uses. A Hyas covered with bright-colored
algee 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, ete., 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 sea-
weed, in eel-grass, and even beneath the surface of the mud. They are
covered with hairs, and sometimes have planted on their backs alge, hy-
droids, and even barnacles. The legs of L. emarginata often spread a foot
ormore. The malesare much larger than the females. The species ranges
from Maine to Florida. JZ. dubia does not extend north of Cape Cod.
It is found more commonly than L. emarginata in very shallow water

SPIDER-CRABS 285

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

HH. 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. Itforms an important part of the food of the cod.

HH. 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 south-
ern 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 Pugetiia

BP. gracilis. A small spider-crab found on the Pacifie coast from
Alaska to Puget Sound. Its body is one half of an inch wide and

Epialtus productus, the kelp-crab ; female.

286 MARINE INVERTEBRATES

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. Thisis one of the most delicately formed of the spider-
erabs. The body has narrow longitudinal stripes of light and dark color.
It lives offshore from Cape Hatteras southward.

Genus Epialtus

E. productus, the kelp-crab. This crab inhabits the coasts of Cali-
fornia 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 hasa promi-
nent 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

LL. 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 ros-
trum points down-
ward; the chelipeds
are very long, the
margins armed with

se spines; the breadth
Lambrus pourtalesii. e 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.)

BOX- AND OYSTER-CRABS 287

FAMILY CALAPPIDE

Grenus Calappa

C. flamma, the box-crab. This singular animal lives on sandy and
muddy bottoms offshore, from North Carolina southward. The cara-
pace is broad and straight on the posterior side, and is curved on the
anterior side, narrowing to the front. The posterior side has promi-
nent denticulations. The body is one and a half inches thick, about
four to five inches wide, and two to three inches long. The chele 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 PINNOTHERIDE

Genus Pinnotheres

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 andtwo conspicuous
spots. The under side of the legs is
whitish. The female is commensal, at
least in the adult form, and its thin,
wa fa aan cpp fe) bnged
with pink. Thespecies P. maculatum ee one,
lives a Mytilus edulis (mussel) and in the ze aden erste: Riese baa
smooth scallop, Pecten magellanicus. The :
oyster-crab is a true messmate, and its presence In the oyster may be ad-
vantageous in helping to provide food for its host. This crab, like the rest,
holds its eggs in the posterior feet until hatched, when the larve leave the
parent and swim about fora 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 chele are weak; and it has no pugnacity, the protection
afforded by the oyster doing away with the need for the common protec-
tive features of its kind. Pinnixa cylindrica, a related species, lives in
the tubes of large annelid worms as a commensal.

288 MARINE INVERTEBRATES

ORDER STOMATOPODA

Genus Squilla

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, in-
stead of laterally compressed. It
/, measures from eight to ten inches
\ My in length andtwo inchesin breadth.

Y vy Instead of chele, 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 ap-
pendages 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

Squilla empusa, the mantis-shrimp. 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

AMPHIPODS 289

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 onthe
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 antenne 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 quan-
tities 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 pre-
pared by a naturalist.

Genus Orchestia

O. agilis, the beach-flea. These little crustaceans exist in countless
numbers under the masses of sea-wrackon 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 antenne
long, on two long, jointed bases. The second :
pair of feet in the males terminate in chele. The last abdominal appen-
dages are stiff and pointed backward. The abdomen is curved under.
The length of Orchestia is half an inch or less. Some species occur onall -
beaches. 0. agilis ranges from New Jersey to Greenland.

Orchestia agilis ; male.

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
19

290 MARINE INVERTEBRATES

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 distin-
guished byits verylong antenne. Another species, T. megalophthalma,
is distinguished by its shorter antenne 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

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 other-
wise 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 tho- Gammarus locusta, the scud.
racic 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 antennulesand antenne 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 antenne ;
the females of all the species have no chelate feet. G. locusta ranges from
New Jersey to Greenland. Thecolor is generally reddish- or olive-brown.
G. annulatus isfound 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 isa smaller slate-colored amphipod found in
some places; another is Mera levis,
which is whitish, with black eyes.

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
Chelura terebrans, the boring amphipod. the wood, while Chelura makes larger
: : burrows in oblique lines near the sur-
face, 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,

TISOPODS 291

Genus Caprella

C. geometrica. These very curious little animals, which are so slen-
der as to seem like skeletons, are found in abundance clinging to hy-
droids, Polyzoa, delicate alge, 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 pos-
terior 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 Caprella geometrica,
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 chele and hooks;
those of the middle section are rudimentary. This animal cannot be:
mistaken for any other. C. geometrica is found fiom 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 gener-
ally 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 fe-
male 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 in-

292 MARINE INVERTEBRATES

habit ponds and streams of fresh water, and still others are found
along the shores of all oceans, abounding among the marine vege-
tation 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 Bopyride attached to its gills.

Genus Cirolana

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 antenna, and underneath is the mouth, which is
covered by the maxillipeds. The dorsal surface is more
or less rounded. At the bases of a]l the segmental thoracic
rings excepting the first one are sutures marking off square,
seale-like pieces (epimera). The epimera form a border
tothe 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
ek for the reception and development of the eggs. This spe-
cies 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

L. lignorum, the gribble. This little isopod is very
destructive in its habits, boring into submerged wood-
work, like the ship-worm (Teredo), and doing great
damage to the piles of wharves, ete. It burrows to the
depth of half an inch, and completely honeyeombs 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 Zmnoria tignorum,
about an inch a year, piles diminish in diameter where Mss icinagaad
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-

ISOPODS 293

logged 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 At-
lantic coast.

GENUS Spheroma

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 them-
selves 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
Spheroma quadridentatum. 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 alge or rocks, and is easily recog-
nized by its habit of rolling itself into a
ball.. Spheroma 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.

Genus Idotea

I. marina (Linneus), I. irrorata
(Edwards). This species is about one inch
long, and is easily recognized by the ab-
domen, 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 thelongest. 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. Idotea marina.

The head is nearly square, the eyes are ; ;

small, and the antenne 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

294 MARINE INVERTEBRATES

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 dif-
fers 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 abdomi-
nal feet are inclosed by the opercular
feet. Eggs and young are carried ina
pouch.

Genus Chiridotea

C. ceca. This species burrows be-
neath 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
iuch in length, with a broad thorax and
narrow abdomen terminating in a point.
It is found on the New England coast.

C. entomon (Linneus). This species
of the northern Pacific coast is from one
to three inches long. The head has the
appearance of two lobes, the sides ‘hav-

Ohiridotea ceca. ing 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

L. polyphemus, the horseshoe- or king-crab. This well-known and
curious animal ranges along the Atlantic coast from Maine to Mexico.

HORSESHOE-CRAB 295

It lives on sandy and muddy shores below low-water mark, where it bur-
rows 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 nip-
pers, which are peculiar to the males. Sometimes the female is ac-
companied 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 espe-
cially interesting from the fact
that it is the last survivor of
an otherwise extinct group of
animals. Its relationships with
classes which have become ex-
tinct, its nearest relatives being
fossils, make it difficult to class-
ify 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 spi-
ders. It has the characteristics
of both groups. There are only
two known species of Limulus
in the world; the other, Limu-
tus moluccanus, lives on the
eastern coast of Asia. L. poly-
phemus often measures a foot in
diameter. The body is com-
posed of three parts. The front
portion, or cephalothorax, is
broad and semicircular, with Under sae of ua aura ae poly.
pusterior angles ending In’ Ziheaing abdominal sppendage; m, month; 0
points. Near each side of its ener p, telson; tigen Ee eephalo-
dorsal surface is a pair of large thoracic limbs.

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 ab-
domen, 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.

296 MARINE INVERTEBRATES

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
chele, or claws. The sixth pair haveno chele, but at the base havea pecu-
liar process termed the flabellum. These six pairs of appendages surround
the mouth, and have bristles at the base which serve as jaws. The sev-
enth 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 re-
semble 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
tuberele supposed to have an olfactory function. Limulus has a blood-
vascular system (the blood being bluish in color), a nervous and a diges-
tive system. It walks with the thoracic feet and swims with the abdom-
inal 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 deter-
mined 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 abdo-
men. There is a pair of short appendages bearing claws (chelz)
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

PLATE LXIV.

Calappa flamma. Calappa flamma, claws open, showing
Lambrus pourtalesii. form of cockscomb.
Limulus polyphemus.

SEA-SPIDER 297

ovigerous legs are run through sac-like pockets and bent under
the body, and thus the eggs are carried until hatched.

Genus Phoxichilidium

P.masxillare. 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.

Phoxichilidium maszillare, enlarged.

VII
MOLLUSCA

TABLE SHOWING THE CLASSIFICATION OF THE MOLLUSKS
DESCRIBED IN THIS CHAPTER

Classes

AMPHINEURA

(Bilaterally symmetrical
mollusks, having shell
composed of eight plates,
or devoid of shell. In-
cluding chitons and their
allies)

GASTEROPODA

(Unsymmetrical univalve
mollusks, usually spiral-
ly coiled. Periwinkles,
whelks, snails, ete.)

SCAPHOPODA

(Mollusks without head,
eyes, or heart, with tri-
lobed foot and tubular
shell open at both ends.
The tooth-shelis)

Phylum
MOLLUSCA

Orders

POLYPLACOPHORA

(Shell composed of eight plates)

APLACOPHORA
(Devoid of shell)

OPISTHOBRANCHIATA

(Branchice, when present, behind

the heart)

PROSOBRANCHIATA

(Branchic situated in front of the

heart)

PULMONATA
(Air-breathing mollusks)

300

Suborders

TECTIBSRANCHIATA
(Branchie more or less
covered by mantle; shell
delicate and often rudi-
mentary )
NUDIBRANCHIATA
(Devoid of shell and
mantle, and without
true branchie)
DIATOCARDIA
(Usually two auricles, two
branchice, and two neph-
ridia)
MONOTOCARDIA
(One auricle, one bran-
chia, one nephridiwm)

Classes

PELECYPODA

(Bilaterally symmetrical,

headless, bivalved mol-
lusks. Mussels, cockles,
oysters, etc.)

CEPHALOPODA
‘Mollusks of high organi-
zation, having a definitely
formed head surrounded
by tentacles ; shell, when
present, usually internal;
shell, external in nautili.

Cuttlefishes, squids, oc-

topi, and nautili)

Subclasses

Tetrabranchiata
Dibranchiata

MOLLUSKS

Orders
PROTOBRANCHIATA

(Gills form a single pair of plume-
like organs, each with two rows of
flattened gill-filaments)
FILIBRANCHIATA
(Two pairs of plate-like gills formed
of V-shaped filaments)
PSEUDOLAMELLIBRANCHIATA
(Gills plaited so as to form vertical
folds)
EULAMELLIBRANCHIATA
(Firm, basket-work gills, the jila-
ments united by vascular connec-
tions)

OCTOPODA
DECAPODA

TERMS USED IN DESCRIBING MOLLUSKS

Abductor muscles: Muscles which move parts away from the
axis.

Adductor muscles: Muscles which draw parts together; oppo-
site of abductor.

Aperture: Opening of the spiral shell.

Bilateral symmetry: Having two equal sides, divided by a

central axis.
Branchie: Gills, or breathing-organs; organs subservient to

respiration through water. Same as ctenidia.

Buccal mass: The mouth-parts as a whole; the organ of pre-
hension 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 uni-
valve shells, round which the whorls are convoluted.

Conerescent : Growing together; uniting.

Cordate : Heart-shaped.

Coste, 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 un-
known function, which fills, at times, the stomach-parts of certain
mollusks.

Ctenidia, plural of Ctenidium: Gills, or breathing-organs,
adapted to water-respiration.

302

DEFINITION OF TERMS 303

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.

Iunule: 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 excres-
cences.

Perios’tracum : Same as epidermis.

Per’istome : In zodlogy, mouth-parts in general ; in conchology,
the margin of the aperture of the shell.

304 MARINE INVERTEBRATES

Porcelanous : Resembling porcelain.

Rad'ula: Same as lingual ribbon.

Reticulated: Having distinct lines or veins crossing like a net-
work ; covered with netted lines.

Sculpture: Elevated or impressed marks on the surface; mark-
ings 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 uni-
valve 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 crusta-
ceous, 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 Varia: 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.

MOLLUSKS

KE now come to another large and important group of ani-
mals, 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 larve 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 zodlogists to-day, this phylum is but the rem-
nant of its former self. Aristotle considered all creatures with
a testaceous covering to belong to a single family, and those
later patriarchs of biology, Linneus, Cuvier, and Lamarck, ex-
tended 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 dis-
covered 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 examina-
tion of their larval stage, to be merely masquerading as mollusks;
and lastly, the brachiopods have been somewhat reluctantly re-

moved from their old position with the mollusks and given the
20 305

306 MARINE INVERTEBRATES

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 con-
sists: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 inter-
mediate 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 con-
sideration 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

MOLLUSKS 307

to choose this field of natural history for special study. But the
true student of zodlogy 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. Ina
sense, the testaceous covering of a mollusk may be likened to an
outer skeleton.

The older zodlogists 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 plaasifcation; 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 in-
vestigation has brought to light. In general, the higher classi-
fication 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 ap-
pearance 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 modi-
fications of the shell are quite certain to take place. Hence a
fairly expert zodlogist should be able to determine with con-
siderable accuracy from an empty and dead shell the anatomical
features of the animal that at one time inhabited it.

308 MARINE INVERTEBRATES

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 faune, 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

MOLLUSKS 309

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 num-
ber 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), Acmea, Margarita, Chiton, Doris, Afolis, 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 prov-
inces, 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

310 MARINE INVERTEBRATES

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. Be-
tween 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 lack-
ing in interest to the shell-collector, it is anything but disappoint-
ing 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 ac-
cepted 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 natural-
ist, for there a better acquaintance is made with the great Carib-
bean province, which, extending from Florida to the northern
shores of South America, embraces all the Bahamas, the West

MOLLUSKS 311

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 quan-
tities 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

312 MARINE INVERTEBRATES

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 charac-
teristic forms, together with a good mixture of species of more
northern habitat; it might properly be regarded as a subproy-
ince. 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 Cglhostoma,
Chlorostoma, Scurria, Acmca, various genera of the Chitgnide,
Purpura, Monoceras, Amphissa, Norrisia, Olivella, Chorus, and
Haliotis.

THE PANAMIC PROVINCE

The warmer waters of the Gulf of California belong to the
Panamie 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

MOLLUSKS 313

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 mar-
velous beauty, occur in their highest development — Voluta,
Mitra, Oliva, Conus, and the various murices. Thére 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 sur-
roundings 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 eoaky or gravelly ground
below low-tide mark. Other mollusks burrow deep in the mud,
many prefer sandy bottoms, while a host of other species sesk
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

314 MARINE INVERTEBRATES

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 micro-
scopic 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 animalcule thus brought
to their mouths. The univalves which possess a siphon are, for
the most part, carnivorous, and are often most voracious crea-
tures. 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 suceu-
lent vitals from within. One energetic little mollusk in particular,
Urosalpins 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 alge.

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 lapil-
lus, resembling little pinkish or yellowish club-shaped stalks, may
frequently be found in the crevices of rocks and under the rock-
weeds. 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 Fulgw are leathery coils of
angular disks adhering by one edge to a connecting-band of a
similar texture. (See Plate I.)

MOLLUSKS 315

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 move-
ments; 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 charac-
teristics 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 repro-
duction. There are some forms that exercise a high degree of
protective mimicry. The highest class of mollusks, the Cephalop-
oda (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 sub-
order will differ so materially in its general characteristies 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 essen-
tial 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 holo-

316 MARINE INVERTEBRATES

thurian, or that poth of these have the closest family ties with
the sea-urchins?

The probable reason for these startling departures from a typi-
cal 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 there-
fore practically impossible, and it seems here as if nature resented
all attempts to cireumscribe her living forms by rigid rules.

The most persistent characteristic of the Mollusca is the posses-
sion 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 comprehen-
sive 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 de-
velop, as we go on, the various types of the actual orders and sub-
orders. There is one class of mollusks, the Amphineura, which
conforms reasonably well in most of its features to our compre-
hension 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 evolu-

MOLLUSKS 317

tionary 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 conse-
quently 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 posi-
tion 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 mus-
cular 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 ex-
tends 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.

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, fieshy 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

318 MARINE INVERTEBRATES

7:770.€.

Ideal or schematic mollusk.

1, dorsal view: h, head; t, cephalic tentacle; sh., shell covering visceral mass; b. m., outline of
body-mass; 7. m.e., edge of mantle; c.t., ctenidia, or gills; g.a., generative apertures; r.e., renal
openings ; ¢. 0., excretory opening; f, posterior portion of foot; 0. e. m., edge of shell.

2, ventral view: h, head; t, tentacle; m, mouth; b, outline of body; e.m., edge of mantle; s./.,
lower surface of foot; ¢. t., ctenidia, or gills; Jf, posterior portion of foot.

3, horizontal section, showing heart, nephridia, and gonads: m, mouth; 0, esophagus; g, gonad;
Pp, pericardium; n, nephridium, or renal organ; v, ventricle; a, auricles; g’, gonad aperture; n',
renal opening; e, excretory opening; j, posterior portion of foot.

4, vertical median section: m, mouth; b.m., buccal mass; 1, liver; d.a@., digestive tract; gq,
gonad; /, foot; g.0., gonad aperture, or opening of oviduct; 7. 0., renal opening; ¢.0., end of diges-
tive tract, excretory opening; n, mantle; r, nephridium, or renal organ; 0. /., recurved portion of
mantle; sh., shell; v, ventricle; p, pericardium.

MOLLUSKS 319

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 auri-
cles. 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 branchie (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 bran-
chi, 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 charac-
teristic 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 branchie.
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

320 MARINE INVERTEBRATES

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 com-
municate 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 branchie, 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 eer opening; is unsegmented; has the ven-
tral surface thickened into a creeping foot or disk; and is pos-
sessed of a head with tentacular processes, a radula, lateral
branchiz, a heart with a ventricle and two auricles, a well-devel-
oped 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 re-

MOLLUSKS 321

ferred to as the foot), as the common garden-snail, the peri-
winkles, 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 Pele-
cypoda have a more or less club-shaped foot, utilized, in the many
families, for a great variety of purposes. They are always in-
closed in a bivalve shell. Familiar examples are the oysters,
the clams, mussels, ete. 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, ete.

CLASS AMPHINEURA

ORDER POLYPLACOPHORA

The Amphineura, as already observed, approach most closely
to the ideal mollusk just described. They are bilaterally sym-
metrical. 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
branchiz 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 mean-
ing “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.
21

322 MARINE INVERTEBRATES

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 ex-
ceedingly tough. In some species it is
covered by a great number of caleare-
ous spicules or granules which are em-
bedded in the leathery mantle tissue.
Strangely enough, the Chitonide (a large
family of the Polyplacophora) possess a
great number of eyes scattered over the
shell plates like minute dots.

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 splen-
did 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 re-
moved from their resting-places by sud-
denly thrusting a knife-bladé under the
foot and prying them off. When thus
detached they have a habit of rolling up
up into a ball and so remaining indefi-
nitely; to prevent this they should be
placed at once in a jar of sea-water,
where they will resume their natural ae
position. For preservation as cabinet cn ctenitins 1, focty ment mi
specimens, chitons should be tied down "edge; ™, mouth.
between two boards or flat substances, to hold them firmly ex-
tended until dried; otherwise they are apt to contract out of
shape.

Six or eight species are exceedingly common upon the west

Chiton spinosus, dorsal view.

MOLLUSKS 323

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 over-
lapping 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 gir-
dle 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.”

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.

Chiton ruber. Chiton apiculatus.

ORDER APLACOPHORA

This second order of the Amphineura is entirely destitute of
the shell plates characteristic of the first. The outer mantle sur-
face, 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 degen-
erated from some higher type. They are supposed to be com-
mensal in habit and live in the dgeper water offshore.

The Aplacophora are not littoral animals, and it is extremely
unlikely that one will ever encounter them upon the beach, un-
less, 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.

TABLE SHOWING THE CLASSIFICATION OF THE GASTEROPODS
AND SCAPHOPODS DESCRIBED IN THIS CHAPTER

Phylum
MOLLUSCA

Class
GASTEROPODA

Order OPISTHOBRANCHIATA

Suborders Families Genera Species
TECTIBRANCHIATA

B. occidentalis
B. nebulosa

B. (Haminea) solitaria
BULLIDZ Bulla

APLYSIIDZ Aplysia A, Wilcoxii
NUDIBRANCHIATA
DENDRONOTIDZ Dendronotus D. arborescens
ZOLIDIDZ Holis 4. papillosa
DORIDIDA Doris D. bitamellata
Order PROSOBRANCHIATA
DIATOCARDIA
A, testudinalis
A, testudinalis,
Acmcea Var. alveus
; ACM AIDA A Wien:
A. patina
Lottia L. gigantea
{r alternata
Fissurella F. barbadensis
FISSURELLID A F. (Glyphis) aspersa
Lucapina L. crenulata
if HX, splendens
HALIOTIDZ AHaliotis HI. rufescens

HA. cracherodii
324

. GASTEROPODS 325

Suborders Families Genera Species
M. cinerea
Margarita {ar - helicina
M. undulata
C. occidentale
C. jujubinum
Calliostoma C. annulatum
C. canaliculatum
C. costatum
Chlorostoma ; C. funebrale
C. brunneum
Trochiscus T. norrisit
Livona L. pica
T. castaneus

TROCHID

T. castaneus,
Var. crenulatus
N. peleronta

TURBINIDZ Turbo

N. tessellata
N. versicolor
N. reclivata

N. viridis

Nerita

NERITIDE

Neritina ;
MONOTOCARDIA

JANTHINIDE Janthina J. fragilis

S. lineata
S. multistriata
scaLipa = Scala {3 groenlandica
S. angulata
P. (Lunatia) heros
P. (Lunatia) triseriata
P. (Lanatia) lewisit
. (Neverita) duplicata
» (Neverita) recluziana

Polynices
NATICIDE

. clausa

- canrena
S. perspectivus
C. fornicata
C. plana
C. aculeata
C. striatum
C. spinosum

L. litorea
f rudis

Natica
Sigaretus

Crepidula
CAPULIDE

Crucibulum

L. palliata
L. trrorata
L. angulifera
L. scutulata
L. planaxis

LITTORINIDA < Littorina

—_—_——_—~_O hh S_OS EES

326
Families

LITTORINIDA

CERITHIID

VERMETIDA

STROMBIDZ

CYPRAIDA

DOLIIDA

CASSIDID AR

MURICIDA
Subfamily
Muricine

Subfamily
Purpurine

}

Genera
Lacuna

Tectarius
Cerithium
Bittium

Cerithidea

MARINE INVERTEBRATES

Species

LL. vincta
; T. muricatus
T. nodulosus

C. floridanum
C. muscarum

C. minimum

B. nigrum
; C. scalariformis

C. sacrata

Vermicularia V. spirata

Strombus

Trophon
Urosalpinx
Eupleura

Pteronotus

Ocinebra

Cerostoma

Monoceras
Chorus

S. pugilis
vs gigas
C. exanthema
C. spurca
C. spadacea
T. pediculus
T. quadripunctata
T. californica
VT. solandri
D. galea
} D. perdix
P. papyratia
C. tuberosa
C. cameo
C. testiculus
C. inflata
M. rufus
} M. pomum
T. clathratus
U. cinerea
E. caudata
P. festivus
O. poulsoni
jo. turida
O. interfossa
; C. nuttallit
C. foliatum
P.lapillus
P. patula
z hemastoma
P. crispata
P. lima
P. saxicola
M. lapilloides
} M. engonatum
C. belcheri

GASTEROPODS 327
Families Genera Species
C. mercatoria
C. (Anachis) avara
ire C. similis
COLUMBELLIDZ Columbella C. (Astyris) lunata
C. (Amphissa) corrugata
C. (Astyris) gausapata
N. trivittata
N. obsoleta
N. vibex
NASSIDZ Nassa N. fossata
N. perpinguis
N. tegula
- N. mendica
Buccinum B. undatum
Chrysodomus CC. decemcostatus
BUCCINIDE < Sipho } iS. Slamepsons
S. pygmeus
Siphonalia S. kellettii
Tritonidea T. tincta
F. carica
F. canaliculata
TURBINELLIDA ea F. perversa
F. pyrum
Melongena M. corona
F. gigantea
FASCIOLARIIDZ Fasciolaria F. tulipa
F, distans
voLuTIpz Voluta V. junonia :
MARGINELLIDZA Marginella M. apicina
Oliva O. literata
— O. mutica
OLIVID | Olivella O. biplicata
O. boetica
C. floridanus
cONIDZ Conus ; Open
CANCELLARIIDZ Cancellaria C. reticulata
Class
SCAPHOPODA
D. dentale
Dentalium D. pretiosum
DENTALID AS D. hexagonum
Entalis E. striolata

CLASS GASTEROPODA

HE 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
game 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 modifica-
tion of these organs will be found when we come to examine
some specimens. The mantle is always present, excépt in the
nudibranch or non-shell-bearing forms; but in few of the Gas-
teropoda 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 struc-
ture of the ideal mollusk, is the fact that they are always asym-
metrical—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 de-
scriptions 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, ete., of similar

shape and construction. So far at least as the external features
328

GASTEROPODS 329

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 ori-
fices for the genital and renal glands are also placed in this
unexpected anterior position. The gills, or branchie, 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 ex-
pect 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

330 MARINE INVERTEBRATES

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 branchiz 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 diges-
tive tract has been bent upon itself and twisted from a straight
course into a curve of almost 180°, 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 move-
ment, 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. Tite, mantle por-
tion covering the visceral hump naturally continued to secrete its
shell, though always in conformity with the change, tle 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. Buccinuwm 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

GASTEROPODS 331

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 main-
taining 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). ny Crete ee ae
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.

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 Jnttorina (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 cal-
careous, 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

“332 MARINE INVERTEBRATES

large orders of the Gasteropoda. The figures represent some of
the commoner types of opercula.
The opercula have been utilized a great deal in the classification

Various forms of opercula.

Turbo Turbo Livona, Ampullaria. Natica.
(Sarmaticus). (Callopoma).

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.

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.

GASTHROPODS 333

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 isa 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 con-
veniently placed just at the end of this long, trunk-like organ.
The genera which have no proboscis are, almost without excep-
tion, 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 secre-
tion 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

334 MARINE INVERTEBRATES

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 ocecu-
pied 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 maine
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 (Cyprea)
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 (Siga-
retus, Natica, ete.).

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 Buccinwm 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.

°

GASTEROPODS 335

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 admir-

‘ ip nN,

sap
Sigaretus levigatus, 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) : J, liver; s. ap., aperture of proboscis, here deflected from the median line; ¢, t, tentacles ;
JS, foot.

ably 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.

fe
Oliva textilina showing how the front part of the foot (jf) is devel-
oped into a sort of fender, the propodium (pr.): e, e, eyes; m. ap., front ap-

pendage of mantle; m. ap.’, hinder appendage of mantle, folded into the
suture when the animal is at rest; si., siphon; ¢, ¢, 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

336 MARINE INVERTEBRATES

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 move-
ment, 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 sur-
prisingly 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 thiekens 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 branchie, or gills.

THE BRANCHI#, 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

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 neph-
ridium, 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. bue.g., left buccal ganglion; I. sal. gl., left salivary gland;
neph., nephridium ; neph. ap., nephridial aperture; od., odontophore; oes., Pp us; 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 esoph-
agus; rad. s., radula sac; r. sal. gl., right salivary gland; rect., rectum; sal, du., salivary duct; siph.,
siphon; supra. g., supr ph 1 visceral glion ; tent., tentacle; vent., ventricle.

22 337 S

338 MARINE INVERTEBRATES

(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.

In general, it may be said that the breathing process of mol-
lusks 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 gaster-
opods that are worthy of notice. The gills themselves differ
throughout the various orders of this class both as to their struc-
ture and their relative position; in one of the orders (the Pul-
monata) the gills have entirely disappeared, and are replaced by
a pulmonary sae 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
Inttorinide, 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

GASTEROPODS 339

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 defi-
nitely known, but the supposition is that it is the seat of the
olfactory nerves. The osphradia are not always present, but when-
ever 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 mol-
lusks 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 re-
quires considerable skill, but for the purpose of merely discover-
ing 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 satis-
factory 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.

340 MARINE INVERTEBRATES

RADULA

Hidden among the red stripes of muscular fiber which line
the inner surface of the throat will be found a fleshy strip cov-
ered 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 pelecy-
pods, or bivalves. Usually it lies coiled up like a spiral when
not in use; its purpose is to tear and rasp food.

The radula has been the subject of much study by concholo-
gists, and has furnished the basis for an arrangement of the nu-
merous sections of gasteropods into somewhat well-defined groups.
If the observer has a strong glass he will notice that each trans-
verse 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 radule
there is, besides the me-
dian and lateral teeth, still
another paired row, called
the marginals. In the
accompanying figures are
given some examples which
show small sections of lin-
gual ribbons. While all
the radule of mollusks are capable of being grouped by their
general characteristics, yet in no two species of mollusks are the
radule quite identical.

Three rows of teeth from the radula of Fasciolaria trapezium.

Portion of the radula of Imbricaria marmorata.

GASTEROPODS 341

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 Buccinwm 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 struc-
ture. In some forms the kidney is closely associated with the
gonad, and seems to codperate 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 ven-
tricle and one or two auricles, although in Buccinum and Fulgur
there is but one auricle.

There is nothing remarkable about the vascular system to dis-
tinguish 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.

342 MARINE INVERTEBRATES

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.
Sines Putting aside the bivalves, the uni-

valve or gasteropod shells remain-
ing 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 com-

Tam.
Parts of a gasteropod shell: a, anterior 7 } 1
canal; b, body-whorl; ¢c, columella; U, outer paratively few spiral turns which
lip; m, mouth or aperture; p, posterior end in a blunt apex, giving to the

canal; s, sutures; sp, spire; w, umbilicus.

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 promi-
_ nent shell-characters.

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

GASTEROPODS 343

Murex tenuispina.

Acmea testudinalis, from below.

types of marine gasteropods, and their respective characteristics
may be noted by comparing them one with another: Fasciolaria
tulipa (Plate LX XVI), a Floridian shell; Polynices heros, a com-
mon species found on all the sandy shores of the American At-
lantic coast; Murex tenuispina, an Indo-Pacific species much prized
by collectors; and Acmea testudinalis, commonly found in Maine
and Massachusetts at low tide clinging to rocks.

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 collettively forming the spire of the shell. When the ani-
mal 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

344 MARINE INVERTEBRATES

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 seulpturing
of the whorls is often of great complexity, and exhibits nodules,
varices, ribs, revolving strie, spinous processes, and lines of growth. It
frequently happens that there is a complete absence of any sculp-
turing 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 wmbilicus. 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 sur-
faces 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 short-
ness of the spire, or otherwise altered by special peculiarities. In
Polynices duplicata (page 368), it will be observed that while the

GASTEROPODS 345

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 acci-
dent 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 por-
celanous 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 tex-
ture, 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 membra-
nous 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

346 MARINE INVERTEBRATES

outer covering of the shell is excessively thin. In old speci-
mens 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 speci-
mens 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 tor the epider-
mis of the shell, and as one would therefore expect, this outer-
most 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 ex-
treme tip of the lip this projecting epidermis, just beneath it and
just inside the aperture a thin deposit of shelly matter, just be-
neath 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

GASTEROPODS 347

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 equi-
distant 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 Murer
tenuispina, indicate the existence of finger-like processes extend-
ing 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 cal-
careous 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

348 MARINE INVERTEBRATES

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.

Acmea testudinalis (page 343) presents a special type of gastero-
pod 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
Acmea is an ancestral type just because the simple character of
the shellis suggestive of the model chosen to represent a schematic
mollusk ; anatomically Acmea 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 Mol-
lusca 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

GASTEROPODS 349

rapid. To judge also from the very large number of extinct fam-
ilies 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 Prosobran-
chiata, 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 Cyclostomatide)
that has become entirely terrestrial in habit, its members having
lost their gills and acquired lungs, but their organization other-
wise is so essentially that of the prosobranchs that they have
never been considered as pulmonates.

The main difference between these two orders of marine gas-
teropods is that in the prosobranchs the breathing-organs (the
gills) are placed in a position forward of the heart, and the de-
gree 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 al-
ways 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 ena-

350 MARINE INVERTEBRATES

bled to “ breathe water” through their skin. They are wonder-
fully 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 proso-
branchs 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 ex-
tended 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 proso-
branchs. This order includes the great majority of marine gastero-
pods, 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
OPISTHOBRANCHIATA ; TECTIBRANCHIATA
GASTEROPODA PROSOBRANCHIATA NUDIBRANCHIATA
PULMONATA

PLATE LXY.

Bulla occidentalis, enlarged. Bulla nebulosa.
Lottia gigantea, inside view. Fissurella alternata.

GASTEROPODS 351

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

Hi. 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 colu-
mella is incurved. This little species is especially abundant amines
in shallow water about Vineyard Sound and in Peconic Bay. _ stitaria.

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 foun-
dation. 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 opistho-
branchs, 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 Builide. 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 “sea-

352 MARINE INVERTEBRATES

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. Witlcoxii. 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 cover-
ing, which soon afterward disappears.

A striking peculiarity of the nudibranchs is that the conven-
tional 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,

GASTEROPODS 353

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 Pacifie coasts of North America, and more especially in the
colder waters north of Cape Cod. They are essentially littoral,
and live upon alge 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 alge, 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 nudi-
branchs 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.

4

There are many species belonging to several genera which fre-
quent 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 papille, are delicately transparent, contractile,
and richly colored. The function of these papille 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 per-
haps all over the surface of these branched papille. The liver, which

23

354 MARINE INVERTEBRATES

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.

Dendronotus arborescens.

Genus Molis

ZE. 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, alge, the piling of
wharves, eel-grass, etc., in bays or in rocky tide-pools.e 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 olis 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 zodphytes, or
at times they wind the cord in a coil upon the sur-
faces of stones. When the young first hatch out,

Hiolis papittosa. 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. -olis swims in an in-
verted position, and isat times exceedingly active. It is very variable in
coloring and in the number of cerata.

Genus Doris

D. bilamellata. In Doris we find a quite different type of nudi-
branch from that presented by the two genera Dendronotus and olis.
In one there were numerous branched cerata or dorsal papille, in the
other many plain cerata, and in neither case were there any specialized

GASTEROPODS 355

breathing-organs. In Doris, however, there are no dorsal papille at all,
the back being covered with calcareous spicules, which form a sort of
secondary shell. Thereis a cir-
clet, or rosette, of retractile - -. .
plume-like gills, or branchim, %. ~ 4°
placed in the middle of the back ~- :
posteriorly. There are various * '
species of Doris, and of closely . 4%
allied genera belonging to the &*
family Doridide, which are tobe | :
found along the New England Doris bilametlata.

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.

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 un-
molested for a few moments that they unfold their beauties to the
view. On the Pacific coast there are numerous species of nudi-
branchs, 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 gastero-
pods 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 ex-
hibiting 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

356 MARINE INVERTEBRATES

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 accord-
ing 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 ACMEIDE

-The first family to be noted is the Acmwide. Its principal
genus, Acmea, is well represented on both the east and the west
coast of the United States.

Genus Aemea

A. testudinalis. This species is found in vast numbers all along the
New England shore, clinging to the rocks between tides. They are usu-
ally 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 thor-
oughly cleaned, it generally presents a mottled coloration of pale green,
brown, and white. Inside it is white and nacreous, with a large brown

GASTEROPODS 357

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 crea-
ture unawares, quickly slip a broad knife-blade under the foot, otherwise
it is quite impossible to tear it fromits resting-place. A. testudinalis lives
entirely between tides, and ranges from the northernmost
waters to New York. It feeds upon alge 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 alvews. This variety is smaller,
more fragile, and oblong. It lives upon cel-grass, its oblong
shell being adapted to the narrow leaves of the grass. The
coloration is brighter — reddish-brown spots on a white sur- ;
face. It is exceedingly common on the New England #00 “suai
coast. alveus.

A. mitra. On the Pacific coast there are a number of .
acmeas. 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 FISSURELLIDE

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 Acme@ide, 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 south-
ern shores of the United States, the latter, however, being confined to

358 MARINE INVERTEBRATES

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 HALIOTIDE
Genus Haliotis

This family is closely allied to the Fissurellide. 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 pro-
cesses from the mantle. The outer surface of the shell, before itis
polished, is usually rough and unattractive, but within, when the

GASTEROPODS 359 -

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. Hal-
iotis is a vegetable-feeding genus. They cling with great tenacity
to rocks about low tide, and it requires skill to remove them with-
out breaking the shell. There are several species in California.
The Chinese use the abalone for food, and have waged a persis-
tent war upon the family along the Pacific coast until the speci-
mens are not nearly as commonasformerly. 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.)

» 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 TROCHIDE

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

360 MARINE INVERTEBRATES

long and slender, with short peduncles for the eyes; the opercu-
lum is corneous, with a central nucleus. The animals are herbiv-
orous, feeding upon alge. 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 exten-
sively 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 rep-
resented 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.

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.

M. helicina. A thinner and more globose species than the
last, with a translucent, shining, smooth surface of a yellow-
ish or olive color. MM. helicina is very fond of the leaves of
Laminaria, and is often found clinging to them when
storms have torn these great alge from the bottom and
cast them upon the shore. At Bar Harbor they are com-
mon upon the eel-grass in Rodicks Weir. This species can
generally be distinguished by its iridescent, metallic luster.

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 con-
sidered 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 1s deco-
rated 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.

Margarita
cinerea,

Margarita helicina,

Margarita
undulata,

GASTEROPODS 361

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 com-
mon 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 north-
east 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 erenu-
lated. This very pretty species is not likely to be met with
upon the shore, but may be dredged in shallow water on 2
gravelly bottoms along the Maine coast. Height about “*iostoma
one half of an inch. wastes

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 Ameri-
can Atlantic waters, but they are either rare or have deep-water stations.

C. annulatum. A remarkable species of Calliostoma, found in Cal-
ifornia. 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 sea-
weed. 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 han-
dling 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 noumbilicus. Length one to oneand 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.

362 MARINE INVERTEBRATES

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 LX VIL.)

C. brunnewm. 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 LXVL}

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 alge. It is often found
upon the beach after violent storms. Found in California, south of San
Francisco. (Plate LXVI.) ;

! Genus Livona

I. 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 in-
clined crustacean. When well cleaned it is a beautiful shell, with black
wavy lines over a greenish-white nacreousf dation. 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 LX VII.)

FAMILY TURBINIDE
This family is very closely allied to the trochids, the most
striking difference being in the operculum, which in the Turbinide
is calcareous and usually smooth and very convex on the outside.

PLATE LXVI.

1, Lucapina crenulata. 3, Chlorostoma brunneum.
2, Haliotis splendens. 4, Neritina reclivata, enlarged.

5, Trochiscus norrisi.

PLATE LXVII.

Livona pica, reduced. Turbo castaneus, enlarged.
Nerita peleronta. Chlorostoma funebrale.
Nerita tessellata.

GASTEROPODS 363

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.

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 LX VII.)

FAMILY NERITDE

The Neritide 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 tenta-
cles. 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 LXVIL.)

N. tessellata is a smaller species, with heavy revolving ribs, and is
further decorated with transverse oblique black lines. The operculum
is caleareous. 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 distin-
guished 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

364 MARINE INVERTEBRATES

variously ornamented by bright spots or zigzag lines of colora-
tion. 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 voleanic 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 JANTHINIDE
Genus Janthina

The genus Janthina has an exceedingly thin and semi-trans-
parent shell, deep violet in color on the base and lighter blue on
the spire. An interesting feature of this genus is the mode of de-
positing the ova. The female exudes from a gland in the foot a

GASTEROPODS 365

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

ap a a

ST

SS

Janthina fragilis; FL, float; O, ova; Pr, proboscis; Br, branchie; F, foot.

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.)

” FAMILY SCALIDE

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. Hach rib
represents a rest-period, when the creature thickened the rim of
the shell-aperture. The aperture is generally round, with a con-
tinuous lip. The animal has a retractile proboscis and long,
slender tentacles with eyes at the outer bases, and is a predaceous,
carnivorous creature. Some Asiatic species of this genus, remark-

366 MARINE INVERTEBRATES

able for their beauty and rarity, have been greatly prized by col-
lectors. 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.

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. .

S. groenlandica. Essentially an arctic species,

scata tine. Which has found its way down to the New England

ata, coast. It is readily distinguished by the flattened,

coarsely rounded, revolving ribs, which follow

the volutions of the spire. Over them are the usual trans-
verse heavy ribs peculiar to this genus.

__S. angulata. The whorls touch one another only by the J
ribs, of which there are nine to each volution. This species geatamuttistri
has a remarkably wide range, occurring from Cape ata,
Cod to southern Florida. (Plate LX VIII.)

_ 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 NATICIDE

This large and interesting family is well represented
Scala groen- 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 pos-
sible for it to withdraw so great an amount of body into its shell;
but if it is suddenly seized or irritated, it will quickly demon-

J)

PLATE LXVIII.

Janthina fragilis. Sigaretus perspectivus, upper side.
Scala angulata, enlarged. Sigaretus perspectivus, under side.
Natica canrena. Crepidula aculeata.

: GASTEROPODS 367

strate 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.

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 witha sandy bottom left by the receding tide. It is
usually partially and frequently wholly buried in the sand. The umbili-
cus 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.

P. duplicata. This is even more abundant
than P. heros. Ithasa 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 _Potynices triseriata, young ;
chestnut in color. The surface of the shell is lutte: Wseriata, older
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

368 MARINE INVERTEBRATES

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.

Natica clausa. A Northern
species which is fairly abundant
on the Maine coast. It
has a shelly operculum,
and the umbilicus is @N
neatly closed by a pure
white, shining callosity.
Its length is about one
half an inch, its color Natica
lividwhitetolightbrown, “+
white within. The calcareous operculum at once determines this shell.
This species (as well as the following one) has retained the generic
oe 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 sta-
tions 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.
lewisti is a Northern species, and does not range south of Oregon. Pro-
fessor 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 Cali-
fornia. The umbilicus is closed by a thick, highly polished white cal-
losity, 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 spe-
cial 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.]

Polynices duplicata.

.

GASTEROPODS 369

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 isno 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 CAPULIDE

Genus Crepidula

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 sur-
face 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 in-
terior 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.

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 trans-
lucent. C. plana lives generally within the aperture of
large dead shells. It has a wide range, from Maine to

Crepidula plana. 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, 1s reddish-
brown with a white diaphragm, and has several radiating ribs on the
back, which are inclined to be nodulous. (Plate LX VIII.)
a4

Crepidula fornicata,

370 MARINE INVERTEBRATES

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 ee 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

Crucibulum

siriatum trom & Cup-Shaped appendage attached by one side to the
shinai inner margin of the shell. This latter feature at once

determines the genus.

C. striatum. This species has radiating riblets, cut by
circular lines of growth. No dimension would quite reach
Ti an inch. Itis a common shell on the Atlantic coast, and
Crucibutum will be found adhering to stones and other shells, but it
sie a 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 LITTORINIDE
Genus Littorina

Littorinais 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 lit-
toral 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 abun.
dant evidence of having been at some past time aquatic or ma
rine species. These changes in nature are constantly going on

and the gradual substitution of a lung fora gill is no very start
ling metamorphosis.

GASTEROPODS 371

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 alge 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 Jvttorina 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 longi-
tudinally grooved, and there is a rudimentary siphonal fold in the
mantle. The shells are turbinated, usually heavy, few-whorled,
and with a round aperture.

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 astonish-
ing numbers, living in vast colonies on the rocks exposed
at low tide. The shell is thick, imperforate (no umbil-
icus), 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—some-
times 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.

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 vari-
ety 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

Littorina litorea.

372 MARINE INVERTEBRATES

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 alge, and
on alge. It has been the writer’s experience not to find rudis and litorea
associated together. ; ;

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 alge that form so conspic-
uous 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
rivera not too great for the Designer of these pretty little globular
pows® ‘hells, 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 south-
ern Atlantic waters of the United States by the following exceedingly
common species:

LZ. 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 out-
lines, and the apex is acute. The surface is ornamented
with closely set, revolving ribs; the sutures are indis-
tinct ; 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. Asthe last speciesresembles L. litorea,
so this other common Southern form resembles a greatly “#orina trrerata.
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 revolv-
ing 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 hasa 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

GASTEROPODS 373

between tides. It is essentially a tropical species of very wide and ex-
tended range, but it does not occur north of St. Augustine. At Tampa
it has been found in vast numbers. (Plate LUXIX.)

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, gener-
ally 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.)

EL. 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

Closely allied to Littorina is the genus Lacuna, one species of
which, L. vineta, 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. LZ. 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 = euna
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 CERITHODE

In this family we meet with a somewhat new type of shell—
the long, turriculate shell, with many whorls and with a channeled

374 ; MARINE INVERTEBRATES

aperture. The Cerithude 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, ag 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 grad-
ually 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.) ‘i

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 shovelfu] 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 seulpture-
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
ae avs 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, de-
cussated, blackish shells are to be found on the wiry grasses of
salt-marshes. They are also found on alge at low-water mark.
In Triforis the whorls turn to the left. Range from Cape Cod to
South Carolina.

GASTEROPODS 375

Genus Cerithidea .

C. scalariformis. This species has the suggestive outlines of the
family, but the aperture is simpler. The outer lip is considerably thick-
ened, 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 Fran-
cisco 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 VERMETIDE

Genus Vermicularia

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 conven-
tional design in the fashioning of its shell. At
first the shell starts out in a regular form, and
then the whorls become separated, finally wander-
ing about in a seemingly aimless manner. The
irregular prolongation sometimes measures ten
inches in length. The animal is in no way re-
markable except in having the viscera greatly
elongated and the foot very shortand 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.

Vermicularia spirata.

FAMILY STROMBIDE

This is a particularly interesting family, but it is tropical, and
is represented on the shores of the United States by only one

376 MARINE INVERTEBRATES

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 devel-
oped 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 nat-
urally constitute the creeping-disk is exceedingly small, but the
metapodium (the hinder part of the foot, upon which the opereu-
lum 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 aclaw. Instead of creep-
ing 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, ob-
tuse 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-chest-
nut, 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 as-
sured. This pugilistic Strombus is a very active mollusk, and when
placed in a boat will sometimes effect its eseape 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 oceurring 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

PLATE LXIX.

1, Littorina angulifera, twice natural size. 4, Cerithium floridanum.

2, Littorina scutulata, much enlarged. 5, Cerithium muscarum.

3, Littorina planaxis, enlarged. 6, Cerithidea scalariformis, enlarged.
7, Cerithidea sacrata.

s
*
a
o
—
&
=
»
=
*
*
»
%
*
x

PLATE LXX.
1, Strombus pugilis. 3, Trivia pediculus.
4, Trivia californica.

2, Cyprea exanthema.
5, Trivia quadripunctata.

GASTEROPODS 377

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 inhabit-
ing the tropical seas, and many of them are highly prized by collectors
on account of their great beauty.

FAMILY CYPREIDE

Genus Cyprea

Cyprea 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 col-
lector 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 tothem. In the animal of Cyprea 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 fila-
ments. 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 em-
ployed by the adult.

Among the Cypreide are many remarkable species. The splen-
did Cypreea aurantia, a native of the Fiji Islands, is one of the
shells most sought after by enthusiastic collectors. The natives

378 MARINE INVERTEBRATES

learned its value long ago, and hold specimens of it at very sub-
stantial 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 through-
out 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 attainsa length of from four to six inches, and is so highly pol-
ished 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 sur-
face of the shell glistens in the light.

Genus Trivia

In the genus Trivia the shell is shaped in every way like that of
Cyprea, 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 natu-
ralist Linneus. Like most of the descriptions of the earlier naturalists,
this is very short and inadequate, and would apply equally well to al-
most any Trivia. The color is rose-pink, with several large brownish

splashes on the back. The spire is entirely hidden. Jt is found in shal-
low water in pools, and on the beach after storms. (Plate LXX.)

GASTEROPODS 379

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
Cyprea, 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 cypreas, 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 resem-
bling 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 DOLIDE

This small family furnishes two conspicuously handsome spe-
cies belonging to the genus Doliwm, which range from Hatteras
southward into the West Indies.

GENus Dolium

D. gatlea and D. perdix. The animal in both of these species has a rela-
tively 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 develop-
ment 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 some-
times 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. galeais white, with a lower spireand
deevly channeled sutures. (Plate LXXI.)

Genus Pyrula

P. papyratia. One of the commonest as well as one of the hand-
somest of American shells. It is a Floridian species, found in shal-
low water and on sandy bottoms. The animal greatly resembles that

380 MARINE INVERTEBRATES

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 high}
raised, and there are ribs with very distinct longitudinal lines of growt
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 CASSIDIDE

Genus Cassis

The cassides, commonly known as the “ helmet-shells,” are car-
nivorous 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 pro-
boscis. The footis broad and strong, being well adapted for plow-
ing through the sand. The shell of Cassis is large, generally
heavy and inflated, with a short spire and a short, recurved ante-
rior 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 obso-
lete nodes below are characteristic features of this species. The color is
light yellowish-brown suffused with pink. The aperture and the columel-
lar 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 some-
times 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

GASTEROPODS 381

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 bemg 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 thick-
ened 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 havoe with the more slowly moving
bivalves, which it devours. (Plate LXXI.)

C. injlata. 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. Itis quality rather than quantity
that makes an interesting cabinet. (Plate LXXI.)

FAMILY MURICIDE

SUBFAMILY MURICINE

It seems like making a long leap to pass suddenly from the
Cassidide to the Muricide. 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 Muricide is an exceedingly large one, including a be-

382 MARINE INVERTEBRATES

wildering 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 Muricide are per-
fect 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 aper-
ture. 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 ten-
dency 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. pomuwm. 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 ecom-
pare 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
describe it. Its most conspicuous feature is the large foliaceous varices

Searvet*

Dolium galea.

Cassis testiculus.

PLATE LXXI.

Pyrula papyratia.

Dolium perdix.

Cassis inflata.

PLATE LXXII.

Murex rufus. Murex pomum. Ocinebra poulsoni, enlarged
Pteronotus festivus. Cerostoma foliatum. Cerostoma nuttallii.

GASTEROPODS 383

which cross the whorls, projecting almost one fourth of an inch from the
body of the shell. Between each of these varices isa 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 appear-
ance. The interior is bluish-white. The operculum is corneous, with a
subterminal nucleus. Unfortunately, thisreally handsome shell is usually
inerusted with coralline or calcareous matter, which must be removed
with acid before a good idea of its appearance can be had. In color itis
reddish-brown to dark chestnut on the varices. It is very common on
the west coast of Florida, but rarer elsewhere. (Plate LX XII.)

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 seulp-
tural 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

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 pg, 5h0n
the best conditions for life in the icy waters of Labrador and cian.
Greenland. : ratus.

Genus Urosalpinx

The genus Urosalpina is closely allied to Murex and Trophon.
Several of its species are found on the east coast of the United
States.

U. cinerea. This well-known species is regarded by
Chésapeake 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

ee this destructive little creature is presumed to be in Chesa-

384 MARINE INVERTEBRATES

peake 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 strie.
The anterior canal is produced, and is yellowish-brown within. Length
under an inch.

Genus Hupleura

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 undula-
tions upon the whorls, and a long, narrow anterior canal and
crenulated lip. The animal is white and yellow, and is nota-
Eupleura ble for its activity. Found from Maine to Florida, about low-
caudate. tide mark.

iN ass>

entn
if

~- 1a!

On the west coast of the United States occurs a striking devel-
opment of a group of the Muricide of a curious foliaceous ap-
pearance, 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 Mon-
terey 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

GASTEROPODS 385

than we are giving our specimens. They are O. interfossa, a small shell
with deep spiral grooves, sharp varices, and deep sutures; and O. cir-
cumtexta, also small, but heavy, short-spired, with scalloped or crenu-
lated 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 LX XII.)

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 PURPURINE

This is considered a subfamily of the Muricide, and the group
therefore bears the subfamily termination -inw. There is no
vital difference between it and the subfamily Muricine. The
operculum in the Purpuwrine has a lateral nucleus instead of a
subterminal one, but beyond this there are no essential differ-
ences. 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 Purpurine, 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,
25

386 MARINE INVERTEBRATES

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

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 boul-
ders, or slowly creeping about inthe tide-pools. Thisrather 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 itis a cold-water animal, and
can only survive in open, rocky stations, it will
; probably never pass south of New York. Itis
Joaten sect difficult to describe this well-known species

ger speci- oe i °

Purpura lapitlus. nate 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 anda 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. Nedr the only sand-beach of Bar Harbor is a colony with ver-
milion 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
ridgesarecommon. 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 pre-
daceous Urosalpinx cinerea, but the aceusation is not well founded. Pur-
pura 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, inerusted exterior,
a transparent colorless shelly substance. Dark and chestnut-colored

GASTEROPODS 387

patenes and spots adorn the outer lip. The shell is from two to two
and a half inches long. (Plate LX XIII.)

P. hemastoma. 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. la-
pillus would apply to this species, which oceurs commonly at San Fran-
cisco 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 Cali-
fornian 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 jength. It also runs through the gamut of variations as
to color-scheme and sculpturing, but always preserves a certain indi-
viduality. 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 LX XIII.)

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.

388 MARINE INVERTEBRATES

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 charac-
teristic 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 LX XIII.)

M. engonatum. This species has sharply ridged whorls, and re-
volving 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 LX XIII.)

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 hol-
low, folded spiny processes upon the shoulder of the body-whorl, which
appear like jagged points upon the spire. (Plate LXXIII.)

FAMILY COLUMBELLIDE

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 Buccinide, 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

.

PLATE LXXIII.

1, Purpura patula. 4, Monoceras lapilloides.
2, Purpura crispata. 5, Monoceras engonatum.
3, Purpura saxicola, enlarged. 6, Chorus belcheri.

PLATE LXXIV.

1, Columbella mereatoria, enlarged. 4, Nassa fossata, about natural size.
2, Columbella (Amphissa) corrugata, en- 5, Nassa mendica, enlarged.

larged.

6, Nassa perpinguis, enlarged.

3, Columbella (Astyris) gausapata, much 7, Nassa tegula, enlarged.

enlarged.

8, Siphonalia kellettii, reduced.
9, Tritonidea tincta.

GASTEROPODS 389

on a white background, or of white splotches on a brownish back-
dd. (Plate LXXIV.)

(Anachis) avara, and the variety C. similis. These rather
_or shells, about one half to three fifths of an inch long, occur from
@, -ida northward to Cape Cod. The upper whorls are smooth, the
‘dw er ones are undulated with vertical costs (ten to thirteen), and the
body-whorlis 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 coste, 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 alge 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-codst 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 alge, or crawling about on a soft bottom. On account of its
generic features, combined with the peculiar coloration, the species can-
not 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, notwith-
standing 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
oceurs also along the Californian shore. The aperture is wider than is
usual in this genus. The surface is deeply wrinkled by longitudinal
cost and is encircled by revolving grooves. Length one half of an
inch; color red, or orange to light brown. It is found in shallow pro-
tected 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. Oc-
casionally 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.)

390 MARINE INVERTEBRATES

FAMILY NASSIDE

These are familiar, and often very characteristic, littoral shells
in all parts of the world. Where they exist at all they are gener-
ally 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 Nassidw 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 Nassidw) 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

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 Hat-
teras 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 ee iy
were victims of some cannibalistic brother. The shells of the ‘
Nasside 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

Nassa trivittata, showing the animal as if crawling.

GASTEROPODS 391

deposit of enamel. N. érivittata is about one half to seven tenths of an
inch long, and is yellowish-white. A seriés of revolving grooves cut-
ting 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.

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 colu-
N mellar lip arched, richly calloused, and often granulated at its
base. Thisis probably the first live shell the collector in Florida

wiea Will encounter. The animal is very graceful and prettily

vibes. Marked in color. The terminal cirri on the foot form a

notable feature — a character belonging to the entire family.

N. fossata, N. perpinguis. On the California coast there are the
huge (for this genus) NV. fossata and the smaller but no less interesting
NV. 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 some-
what thickened, and the entire aperture is bright orange. The color of
the shell is ashen-gray, and itis 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. WN. 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 resem-
bles the Floridian N. vibex. N. mendica is a slender shell three quar-
ters of an inch long, with prominent longitudinal ridges, and light brown
in color, with a white aperture. (Plate LXXIV.)

FAMILY BUCCINIDE

From the number of subfamilies and genera included in this
exceedingly large and comprehensive family, it would almost

392 MARINE INVERTEBRATES

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 ani-
mal. 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
Buccinide 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 exten-
sively 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 at-
tracted 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 colu-
mella 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:)

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 coste.

GASTEROPODS

393

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 termi-
nation of the ribs. The columella
is arched above; the canal pro-
duced (sometimes to the left). The
color without is dull ashen-white
to horn; within, pure white. The
operculum is small, with a termi-
nal nucleus. The animal is the
same as Buccinum. This species
is not quite so common as B. unda-
tum, but it is often found asso-
ciated with it. At Eastport and

Sipho Stimpsoni.

Chrysodomus decemcostatus.

Bar Harbor it is abundant just
below low-water mark.

Genus Sipho

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 conse-
quence. It is, in fact, not rare to
any one who is provided with a dredge
and rope enough to enable him to use

394 MARINE INVERTEBRATES

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 epider-
mis 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
smallirregular specks of black. This shell isfound from three
to five inches long.

S. pygmeus. 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.
Stimpsont by the greater number of whorls, the more promi-
nent revolving ridges, and the smaller aperture. The epi-
dermis 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.

Sipho
pygmeus,

Genus Siphonalia

S. kellettii. Siphonalia is one of the Pacific genera of the Buccinide,
which finds its greatest development in Japanese waters. One of these
Japanese species, S. kellettit, is also found in California. It has the typical
animal of the Buccinide, 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 crenuiated 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 cross-
ing 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 TURBINELLIDE
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

GASTEROPODS 395

F. canaliculata, both of which are
exceedingly common in sandy
shore stations from Cape Cod
southward.

F. carica. The largest univalve
north of Hatteras, most easily rec-
ognized by its pear-shaped shell, with
simple suture and brilliant vermilion
aperture. The anterior canal islong

Fulgur carica.

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.
Fulgur canaticulata. 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.
F. canaliculata often occurs associated with the last. It does not
attain quite the same size, but specimens of both species are, on the

396 MARINE INVERTEBRATES

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 num-
bers, 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 ante-
rior canal, a low spire, deeply channeled sutures, flattened shoulders, and
no spinous or nodose processes. Itis ornamented with revolving incon-
spicuous ribs or strie, 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 erenu-
lated appearance of the spire caused by the continuations of the triangu-
lar 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
strie. Length four inches. Found in shallow water. This active pre-
daceous 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.)

* tats sebSf eh

Fulgur perversa. PLATE LXXV. Melongena corona.

Balawy ner
Baalawe newer

Bs (Se, Sennen er ee

‘SUBISIP VILBOLOSe,T

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GASTEROPODS 397

FAMILY FASCIOLARODE

This family comptises 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. Thisis 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 lipis simple. Thescheme of coloration
is variable, but there are two chief patterns, which are usually followed,
though they often are considerably modified. One isa light-bluash 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 cren-
ulations of the sutures, and is perfectly smooth, save for a few spiral
ridges about the base. The color is bluish-white, with clouded longitu-

398 MARINE INVERTEBRATES

dinal 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 min-
utes. Large specimens of F’. gigantea should remain in the pot half an
hour. The heavy corneous epidermis of F. gigantea will dry and crum-
ble away unless it is rubbed with vaseline about once a year.

FAMILY VoLUTDE

Genus Voluta

The Volutidae, like the cowries, are “ aris-
toeratic” shells. As was stated above,
there are many collectors who have be-
come so fascinated by the shells of a few
of these “first families of the Mollusca” that
they make great effortsand spend no small
sums in seeking to complete their cabinet
series of the rare and more beautiful forms.
The Volutide certainly have very beauti-
ful 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-col-
lector, and this is the well-known and
much-sought-after V.junonia. The ani-
mal 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.

Voluta junonia.

GASTEROPODS 399

V. junonia. This volute has never been taken alive in shallow water
near the shore, but is occasionally found cast upon the beach after vio-
lent 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 MARGINELLIDE
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 hun-
dred tropical species do not exceed one half aninch. The animal
is very similar to that of Voluta; indeed, the marginellas were
until recently included in the Volutide. The shell is also sug-
gestive of Voluta. It is porcelanous, highly polished, and shin-
ing 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 incon-
spicuous 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 suf-
fused 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.)

400 MARINE INVERTEBRATES

FAMILY OLIVIDE

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 callonsed 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. Itis 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 ex-
ceedingly 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 conchologi-
cal characters, but the shells are, with few exceptions, exceed-
ingly small, and usually have a somewhat more elongated spire
than is the case in the genus Oliva proper. The animal of Oli-
vella 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 isnot more than one fifth of an inch long, is highly polished and shin-
ing, and yellowish-white in color, with revolving pale rufous bands. It
has the typical oliva-shape.

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 cal-
loused, and has two entering folds near the base. The color is ereamy-
white to dove-color, with a purple sheen over all, and purple markings

PLATE LXXVII.

1, Marginella apicina, enlarged. 3, Olivella biplicata, enlarged.
2, Oliva literata. 4, Conus floridanus.
5, Cancellaria reticulata.

GASTEROPODS 401

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 [0. biplicata] by the
hundreds,” he continues, ‘‘and I had gathered about a thousand before
the tide camein. They seemed to lie in groups just under the surface
of the sand, yet wholly concealed from sight.” (Plate LXXVIL.)

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 cONIDE
GENuUs Conus

This is a comprehensive family of several highly diversified
genera. Its most prominent genus is Conus, a name which indi-
cates the principal feature of the shell, for it is almost an exact
cone in shape. Conus, along with Voluta and Cyprea, 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 ec-
centric markings. Some of the rarer forms are famous in con-
chological annals for the enormous prices which they have
commanded. The rare and beautiful Conus gloria-maris once
brought £48 ($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.

26

402 MARINE INVERTEBRATES

C. foridanus. 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,
bat many-whorled and pagoda-like; the aperture is long and narrow,
and the lip is simple. The coloring i is yellowish, banded ona creamy-
white background, or dotted in circular rows. Length two inches.
(Plate LX XVII.)

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 inlength, 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 CANCELLARIIDE

Genus Cancellaria

The last family of the Gasteropoda to be considered is the Cancel-
lariide, 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 LXXVIL.)

CLASS SCAPHOPODA
FAMILY DENTALIDE

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, Den-

Entalis striolata,

GASTEROPODS 403

talium dentale and Entalis striolata. The first has a simple round
hole at the smaller end of the shell, and is faintly marked by longi-
tudinal striz; 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 Dentalide
range into deep water, many of them living only in

the profounder depths of the ocean. But these two s—
species are exceedingly common in the New England
coastal waters, at very moderate depths, and may
sometimes be found upon the beach east 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 Dentaliwm, 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 oc- g
curs Dentalium hexagonum, a very delicate
little species with a slightly angulated shell.

The animal of the Dentalidw is remark- 7_,
able, and easily merits the rank of a sepa-
rate molluscan class. It has no
head, no tentacles, no eyes, no
heart, and no gills. Itis a mol-
lusk because it has a mantle, & —Dentatium, as seen in longitudinal section (ex-
foot, and aradula. Its position, sovt_th £009: 5 shel: 2, mantle; Sn, shell
therefore, is between the Gas- voile nemnence or oral nes 7 came
teropoda, which it resembles in cerebral ganglion; N, kidney; Ge, generative
its univalve shell and radula, and oe
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.

404 MARINE INVERTEBRATES

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 Dentalide 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.

TABLE OF THE COMMONER NORTH AMERICAN PELECYPODS
DESCRIBED IN THIS CHAPTER

Class
PELECYPODA
Orders Families Genera Species
PROTOBRANCHIATA
Nucula N. proxima
Leda L. tenuisulcata
ee ¥. limatula
Yoldia Y. thracicformis
Y. sapotilla
SOLENOMYIDZ S§o0lenomya S. velum
S. borealis
FILIBRANCHIATA
A. simplex
Anomia A. aculeata
ANOMIIDZ A, lampe
Placunanomia P.macrochisma

ARCIDZ Arca

Mytilus
MYTILIDA

Modiola

PSEUDOLAMELLIBRANCHIATA
Avicula
AVICULIDA \ Pinna

Perna

OSTREIDZ Ostrea

PECTINIDZ Pecten

405

A. ponderosa
A. noe
A. pexata
§ M. edulis
) M, hamatus
M., californicus
M. modiolus
M. plicatula
M. tulipa
M. recta

A, atlantica

1 P. muricata
P. seminuda
P. ephippium
O. virginica

O. frons
O. lurida
P. magellanicus
P. irradians
P. dislocatus
P. islandicus
P. equisuleatus
P. hastatus

406 MARINE INVERTEBRATES

Orders Families
EULAMELLIBRANCHIATA

CARDITID

ASTARTIDA
CYPRINIDS

LUCINIDA

TELLINIDZE

DONACIDAG

MACTRIDA

VENERIDA

Genera

Cardita

Astaite
Arctica

Ducina

Loripes

Tellina

Macoma

Donax

Mactra

Reta

Venus

Cytherea
Dosinia
Tivela
Tapes

Chione

Saxidomus

Species

C. borealis
; C. floridana
A, castanea
} A, undata
A, islandica
L. tigrina
L. floridana
L. pennsylvanica
L. dentata
L. californica
L. nuttaliii
LL. edentula
T. radiata
T. alternata
T. bodegensis
T. tenera
MM, secta
M. nasuta
M. baltica
M. proxima
M. tenta
; D. variabilis
D. californicus
M. solidissima
M. similis
M. ovalis
M. lateralis
R. canaliculata
V. mercenaria
Var. mortoni
V. cancellata
§ C. (Callista) gigantea
(C.(Callista) maculata
; D. discus
D. elegans
T. crassatelloides
; T. staminea
T. laciniata
C. succincta
} C. fluctifraga
C. simillima
S. nuttallit

Families

PETRICOLIDA

CARDIIDA

MYIDA

SOLENIDZ

GLYCIMERIDA

PHOLADIDA

TEREDINIDA
PANDORIDZ

PELECYPODS
Genera

Petricola

Cardium

Mya
Ensis

Solen

Tagelus
Glycimeris

Pholas
Zirphea

Teredo
Pandora

Species

{ P. pholadiformis
P. carditoides
C. magnum
C. isocardia
C. levigatum
C. serratum
C. mortoni
C. substriatum
C. corbis
C. quadrigenarium
C. elatum
C. islandicum
C. pinnulatum
M, arenaria
E. directus
S. viridis
S. sicarius

Ls. 1Osaceus
T. gibbus
G. generosa
P. costata

{ P. truncata
P. californica
Z. crispata
T. navalis
P. trilineata

407

408 MARINE INVERTEBRATES

Anatomy of a pelecypod, Anodonta cygnea. The animal with most of the left mantle lobe removed,
a, excretory opening; @.ad., anterior adductor muscle; a.7., anterior retractor muscle; au., left
auricle; d.p.a., dorsal pallial aperture; ex. sph., exhalant siphon; /t., foot; in. sph., inhalant
siphon; kd., kidney; 1. ext. gl., left external gill; J. ext. plp., left external labial palp ; 1. int. gl., left
internal gill; 1. int. plp., left internal labial palp; 1. m., cut edge of left mantle lobe; mth., mouth;
p.ad., posterior adductor musele; pe., pericardium; p.7., posterior retractor muscle; pre., pro-
tractor muscle; ret., rectum; r.m., right mantle lobe; v, ventricle; v. m., visceral mass.

gor Te

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; /t., foot; g. ap., genital aperture.
gon., gonad; gul., gullet; él. j., interlamellar junction ; in. sph., inhalant siphon ; int., intestine ; kd.
kidney; m, mantle; mth., mouth; p.ao., posterior aorta: p.ad., posterior adductor muscle; pe.,
pericardium ; pd. gn., pedal ganglion; r.ap., renalaperture; 7. au., right auricle; ret., rectum;
Tr. p. a., reno-pericardial aperture ; st., stomach; ty., typhlosole; v., ventricle; v. gn., visceral ganglion ;
w.t., water-tubes.

CLASS PELECYPODA

HIS is a large and important class of the Mollusca, compris-
ing 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 cov-
ered 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 develop-
ment 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.
409

410 MARINE INVERTEBRATES

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 Car-
dium 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 pre-
pared “upon the half-shell.”

s 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 papille, and is often richly colored. Mr. Hickson, a nat-
uralist, 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

PELECYPODS 411

a—=-
--->

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: 4, excurrent; B, incurrent siphon; F, foot. 3, Scrobicu-
laria piperata, in its natural position in the sand, showing very long tubular siphons: 4, excur-
rent siphon; B, incurrent siphon.

the mantle lobes unite in order to form two openings. These
openings are called the siphons.

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 man-
tle 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 integu-

412 MARINE INVERTEBRATES

ment, 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.

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., 8. b., anal and branchial siphons; 1, 2, 3, first, second, and third points of closure of
mantle; b.0., 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 toge-
ther at other points. Indeed, the fusion of the mantle-edges may
become almost complete; but it always leaves the siphonal open-
ings 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 corre-
spond closely with certain changes in the organization of the ani-
mal, and this feature must be regarded as a very important
character.

PELECYPODS 413

The figures on pages 411, 412, and 413 show the degrees of man-
tle 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 in-
tegument. To the right of this cut may be seen the foot project-
ing 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 pro-
jects 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 projec-
tion to the left, the only other
opening is the very small orifice
marked “2,” for the accommo-
dation of a small, insignificant
foot. In the other figures dif-
ferent degrees of mantle fusion |
are indicated.

Before removing the mantle —
from one side of the specimen , #),> BT uphowe; fpelsl opting n
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. Morphologi-
eally it is the survival of the posterior adductor.

THE BRANCHIZ OR GILLS

Removing carefully the thin, fleshy mantle, the gills are ex-
posed to view—that is, of course, the gills of that side of the

414 MARINE INVERTEBRATES

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 hair-
pins, 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 aérated 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 fami-
lies 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 lodg-
ment upon the body-surface, but usually only upon the gills,
where they remain as in a brood-pouch between the lamelle of
the inner and outer gills) When the eggs hatch, the free-swim-
ming 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.

PELECYPODS 415

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 or-
gan. In the oyster the
foot has become almost en-
tirely atrophied; the sta-
tionary life led by the ani-
mal renders such an organ ;
quite unnecessary. Ex-~
cepting in a few families,
the pelecypod foot is well _ Bi Zz

ss 7
developed. Ina number Mytilus edulis, attached by its byssus (By) to a piece of
of generathe foot contains ine dhs me ee siphon, the branchial siphon
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 per-
manent lodgment. The
accompanying cut shows
Mytilus edulis, a common
east-coast pelecypod, at-
tachéd by its byssus to a
piece of wood. Most bi-
Pecten opercularis, showing the ocelli, or eyes, on the valves having a strong bys-
eager eaters sus exhibit a feeble develop-
ment of the foot; nearly all bivalves, however, show traces, some-
times only in the embryo, of a byssal gland.

The visceral mass contains the liver, the exceedingly large gen-
erative 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.

416 MARINE INVERTEBRATES

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 ven-
tricle and two lateral auricles, each connected with the branchie
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 them-
selves; 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. Sur-
prises are always in store, and sometimes the peculiar juxtaposi-
tion 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 satis-
factory 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

PELECYPODS 417

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 appear-
ance which is lodged just with-
in the hinge, and is compressed
when the valves are closed to-
gether. Thus, when the valves
are closed, there is always a strain
upon the adductor to overcome
the elastic resistance of the car-

. 7 The interior characteristics of a pelecypod
tilage. When a pelecypod dies shen. rett valve of Venus gnidia: 4, anterior, B,

posterior, C, dorsal, D, ventral margin; 4B,

and the pull of the adductor mus- length, CD, breadth of. shell; a.m., anterior,
7 p.m., posterior impressions of adductor muscle;

cles 18 released, the valves gape p, pallial line; p.s., pallial sinus; 2, ligament;
open. lw., lunule; wu, umbo; c, cardinal teeth; a.J., an-
terior lateral tooth ; p. l., posterior lateral tooth.

The summit or apex of the
valve is called the wmbo, 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 man-
tle 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 adja- _
cent to the umbones, is known as the dorsal margin of the shell, in
contradistinetion 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
27

418 MARINE INVERTEBRATES

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
Iwutle. 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 remember-
ing 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 inter-
locking 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 dis-
tinction 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 cer-
tain 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 diucctn, 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

PELECYPODS 419

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 diam-
eter 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 Veneride 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, sub-
orders, ete., 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 branchie, and has
practically replaced all the older classifications, which depended

420 MARINE INVERTEBRATES

upon the presence or absence of siphons, the degree of mantle
fusion, the arrangement of teeth upon the hinge, the number of
adductor muscles, ete. 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 effi-
cient 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 modifica-
tion according to environment and changed conditions.

The five orders of the Pelecypoda are: Protobranchiata, Fili-
branchiata, Pseudolamellibranchiata, Eulamellibranchiata, Septi-
branchiata.

Structure of the branchie or gills of : pelecy pods, seen diagrammatically i in section:

A, Protobranchiata; B, Filibranchi Cc, hiata; D, Septibranchiata ;
e,e, external row of filaments; i, i, incernal row of filaments; ¢, external row or
plate folded back; 7’, 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 sur-
face 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

PELECYPODS 421

developed. The adjacent filaments are connected, not by cilia,
but by vascular channels, and the depending and recurved por-
tions 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 cham-
ber 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 fasci-
nated 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 men-
tion briefly some of the commonest species.

ORDER PROTOBRANCHIATA

FAMILY NUCULIDE

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 Nuculide
to form two short siphons. The palps are exceedingly large. The
foot is also large, and by its disk-like surface is adapted to creep-
ing, much as is a gasteropod foot ; its edges are often crenulated or
scalloped, and there is no trace of a byssus. The shells are equi-

422 MARINE INVERTEBRATES

valve, 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 epider-
mis, 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 har-

procima, bors of the New England coast.

Genus Leda

E. tenuisutcata. 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 es
bottom in shoal water on the New England coast. Leda tenuisulcata,

Grnus Yoldia

Y. limatula. This species: has the same sort of toothed hinge exhib-
ited 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 mar-
gins. 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.

Y. thraciceformis. 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

Yoldia limatula.

PELECYPODS 423

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 epi-
dermis, 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 eigh-
teen pointed ==
teeth on each Yoldia thracicyormis.
side. In length
it is little less than an inch. Found from Long Island
Sound northward.

Yoldia sapotilla,

FAMILY sOLENOMYIDE

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 be-
yond 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 occa-
sionally found upon the beach between tides. Chelsea Beach,

just north of Boston, is an often-quoted locality.

ORDER FILIBRANCHIATA
There are several families of this order which are well repre-
sented 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

Solenomya velum,

424 MARINE INVERTEBRATES

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 ANOMIIDE

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, occu-
pies 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 Yost 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.

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 var-
iously undulated and
plaited in accordance with
the surface of the ob-
ject to which it is at-
tached. Thousands of
these valves, disjointed
and separated, are cast
upon the beachesall along
our Atlantic coast. They
are light green to sal-
mon- or copper-color,
generally fragile and
sealy, and have a _pecu-

liarly dulled (as though
Anomia simplex, side view. Anomia simplex, from below. greased) nacre.

PELECYPODS 425

A. aculeata is much smaller than the last species.
and the surface of the convex valve is roughened AWS:
by prickly scales. The smaller valve is very thin, §
ae almost cas i pan oa the byssus. Es38 y

ts diameter is about half an inch. Found at- ; ; 1
tached to stones, ete., about the holdfasts of Fucus. “inomiacsuteata 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 accom-
modate 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 with-
out. Two to four inches in diameter. (Plate LXXVIII.)

FAMILY ARCIDE

GENUS Arca

The Arcide 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-fila-
ments are entirely free, there being even no ciliary junctions.

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
arow posterior to the beaks, while
just under the beaks are a num-
ber of irregular cartilage-pits.
About thirty-two to thirty-six ra-
diating ribs ornament the shell.
The inner margins of the shell are
rather deeply scalloped; the epi-
Arca pecata, dermis is thick, shaggy, and dark

426 MARINE INVERTEBRATES

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 promi-
nent, 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.nocw. 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 areas, 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 LXXVIILI.)

FAMILY MYTILIDE

GreneRA Mytilus, Modiola

The Mytilide are a large family, including the mussels, so com-
monly found between tides upon all shores. The two ordinary
genera Mytilus and Modiola, which often occur associated to-
gether 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, com-
monly known as mussels, have acquired the stationary habit and
are provided with a relatively small foot (in some species amount-
ing to no more than a mere tubercle); but in place of a useful
foot is a well-developed byssogenous gland, which secretes an ex-

PLATE LXXVIII.

Placunanomia macrochisma. Arca ponderosa.
Arca now Mytilus hamatus.

PELECYPODS 427

ceedingly 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 edulis, typical form.

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 Mytilide 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 struc-
ture of the animal, gills, mantle, foot, and all. At times the
whole being is a veritable receptacle for myriads of tiny yellowish
eggs.

The Mytilide 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.

428 MARINE INVERTEBRATES

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 down-
ward, and the ventral margin pro-
jects 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. Itis brightly rayed in
green.and yellow. M. edulis occurs in Europe, where it is quite exten-
sively used as food. It also occurs (by importation) in San Francisco
Bay.
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 sta-
tion among rocks exposed to the surf. It is about the same size as M.
edulis, but has a lighter brownish glossy epidermis and several con-
spicuous, well-rounded, radiating ribs. The animal is orange-colored.

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 full-
ness 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
“oreat horse-
mussel.” Some-
times 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 Modiola modiotus,

Mytilus edulis, rayed-color variety.

PELECYPODS 429

are not easily detected. They are not uncommon in such stations at
Mount Desert, Maine.

M. plicatula. This species of Modiola ranges from Canada to Hat-
teras, and inhabits the tidal waters of streams, sheltered muddy reaches
among reeds, and tidal flats. Itisa dingy-looking shell, ornamented with

Modiola plicatula, typical form.

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 itis 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 Mainé 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 ob-
jects 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 cen-
tral portion.

M. recta. A species
of Modiola fairly abun-
dant on the Pacific coast’
from Vancouverto south- Modiola nigra.
ern California. It has a i a ded
long, narrow shell with a dark-brown glossy epidermis; lighter pos-
teriorly, 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 fami-
lies in which the gills are filamentous, but in which the filaments

430 MARINE INVERTEBRATES

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 in-
stead 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 AVICULIDE

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 Aviculide is of a highly polished nacre,
and some of the larger species have been extensively collected for
mother-of-pearl. To the Aviculide 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 isan
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 va-
rious 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 striz of the undulat-
ing 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

PELECYPODS 431

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 dia-
mond. 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 inte-
riors 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 com-
mercial 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 alge 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 spe-
cies at once. The structure of the shell is unusual in being so largely
composed of organic matter that it possesses elasticity near its thin-
ner 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 asso-
ciated 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 numer-

439 "MARINE INVERTEBRATES

ous 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 ani-
mal’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 fila-
ments being clearly united by vascular channels. A very curious develop-
ment of the osphradium (see page 339) into an erectile process capa-
ble 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 distinguish-
ing 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 OSTREIDE

This family probably interests more people than any other one
in the class save Aviculide. 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.

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-shels, 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 cen-
turies. Shell-mounds are found along the coasts of Florida and
are of some archxological value. The cultivation of oysters as
recorded by Pliny dates from the first century B.c., at which

PLATE LXXIX.

Pinna muricata,
Pinna seminuda.
Pecten hastatus.

PELECYPODS 433

time a Roman named Sergius Orata first cultivated oysters at
Baiz. 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 Luerine 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 ovovivipa-
rous; 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 larve 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
larve 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
28

434 MARINE INVERTEBRATES

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 pre-
daceous 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. Oys-
ter-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 uti-
lized 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 ene-
mies. At low tide the young oysters are carefully examined
and sorted, and at the right age they are removed to open areas.
The pare 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 pare is sepa-
rated from that of his neighbor by canals of greater width, and
often by stakes having a few branches on the ends. These pi-

PELECYPODS 435

gnons, which sway in the wind, are said to frighten away the pre-
daceous ray which is apt to hover about the preserves. The
pares are finally thinned out by sending the oysters to other
pares to be fattened. There is a celebrated parc délevage at
Marennes. It is a collection of artificial ponds, the fioors of
which are covered with alge, 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 liga-
ment. 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 pur-
plish 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 PECTINIDE

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 char-
acters. The outline of Pecten has been considerably employed
in conventional designs for mural decorations; indeed, the figure

436 MARINE INVERTEBRATES

of a well-known Mediterranean pecten (P. jacobius), found com-
monly 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 crea-
ture. It can propel itself through the water by spasmodically clos-
ing 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, appa-
rently, 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. tenu-
éscostatus — a name given to it on account of its very numerous radiat-
ing striz; but it was later discovered that the North Atlantic form was
in reality the same asthe 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 1s 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 promi-
nently raised ribs (about fifty to one hundred in number), which are cov-

PELECYPODS 437

ered with a multitude of erect scales. The ribs persist upon the interior of
the shell. The “ears” are unequal in size. The coloris light orange to
reddish-brown, with zones
of darker and richer col-
or. One valve is flatter
than the other and more
lightly colored. Greatest
length about three inches;
height three and a half
inches. Thisisa Northern
shell, belonging to the
waters of Newfoundland,
but its valves are fre-
quently cast upon the New f
England beaches.
- trradians. The §
common — shallow-water
species of the Atlantic
coast. This exceedingly
abundant species does
not range north of Bos-
ton, but finds an exten-
sive habitat to the south.
Its metropolis is Cape
Cod, Long Island Sound,
and the Jersey coast Pecten islandicus.
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 ashengray. 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 per-
haps 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 coloritis 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 1ts murky depths. .

438 MARINE INVERTEBRATES

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 dislo-
catus. 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. wslandicus —
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 alter-
nately 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 LX XIX.)

P. equisulcatus. The
Southern species above re-
ferred to as resembling P.

Pecten irradians, typical form. trradians or dislocatus. It

has about twenty stout,

well-rounded ribs, with concentric wrinkles between them. The “ ears”

are equal. The size and shape are asin 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 Eulamellibranchi-
ata we find all the families to be possessed of the basket-
work or crisscross branchial structure. Each gill is fun-
damentally 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 con-
nected by truly vascular channels. The closer connection of the
filaments to form of each gill a sort of plate is further effected

PELECYPODS 439

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 con-
nects. 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, consti-
tuting the division of the two into the anal and branchial
siphons.

Another feature of this order is the marked tendency to man-
tle 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 CARDITIDE

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 Carditide
refers to the heart-shape of the shells.

440 MARINE INVERTEBRATES

Genus Cardita

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. Theepidermisisrusty-brown. The hinge
‘is strong, with two prominent teeth; the mar-
gins 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 numer-
ous 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.

Cardita borealis, natural size.

FAMILY ASTARTIDE

Genus Astarte

Notwithstanding their rather small size, there is a trimness
about the shells of Asfarte which, taken together with their
rich chestnut epidermis, makes them very interesting and desira-
ble 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 fre-
quently 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

PELECYPODS 441

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.

A. undata. A species slightly larger
than the last, with ten to twenty promi-
nent concentric undulations.

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.

Astarte castanea.

Astarte undata.

FAMILY CYPRINIDE

Genus Arctica

This family is represented by one species upon the New Eng-
land 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 fisher-
men along the shore.

A. (Cyprina )istan-
dica. This clam has a
thick though not pon-
derous shell, with promi-
nent 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 Arctica (Cyprina) islandica.

442 MARINE INVERTEBRATES

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 LUCINIDE

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 ver-
miform 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 Lucinidw, more so than in most other
peleeypods, the chief function of the gills is to furnish a brood-
ing-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 costz which are crossed and decussated through-
out with concentric ridges. The color is white. This fine shell lives
only in southern Florida and is abundant in shallow water on sandy sta-
tions. (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 um-
bones, 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,

PELECYPODS. 443

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.)

I. 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.

LE. 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 decus-
sated 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.)

Lucina dentata.

GENUS Loripes

ZL. 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
ee aad about the pallial line and muscle-scars. (Plate

FAMILY TELLINIDE

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

444 MARINE INVERTEBRATES

animal of Te/lina 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 bys-
sogenous gland, thére is no actual byssus. The shells are por-
celanous 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 nu-
merous impressed concentric lines. The color is uniformly white or yel-
lowish, 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 spe-
cies as in the last, namely, a slight twist or bend to one side in the pos-
terior end of the shell.

T. tenera. A little Tellina
i) found in New England waters,

< a which, though very small, is

: : SS worthy of mention on account
Tellina tenera, showing ex- ; ll

tended’ animal. > Teltina tenera. 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; some-
times 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.)

M.nasuta. Another Californian species, with a less shining surface
and a very thin light-brownish epidermis. The twisting of the posterior

1 enw te 3c” Wee FE

SS]

PLATE LXXx.

1, Lucina tigrina. 3, Lucina pennsylvaniea.
2, Luceina floridana. 4, Lucina nuttallii,

5, Loripes edentula,

PLATE LXXXI.

1, Tellina alternata. 3, Donax variabilis.
2, Macoma secta. 4, Donax californicus.
5, Reta canaliculata,

PELECYPODS 445

margin is striking. It has very fine cardinal teeth. Length two to
three inches.

M. baltica, M. proxima, 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, slen-
‘der 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 Macoma baitica,
labial palps, is exhausted of its air and nutriment
and contaminated by waste products. MV. 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.

FAaMILy DONACIDE

Genus Donax

The Donacide are represented upon our coasts by compara-
tively few species, all belonging to the genus Donaz. The shells
are under an inch in length, and have a peculiarly shortened an-
terior portion; thus they are inequilateral. Their ventral mar-
gins 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 longi-
tudinally with excessively fine riblets. Length one half of an inch or
slightly more. In Marchand 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 jewelsin
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 lit-
tle 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.

446 MARINE INVERTEBRATES

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 geographi-
cally, thus leading us to separate them specifically. (Plate LXXXI.)

FAMILY MACTRIDE
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.

M. solidissima is
one of the very com-
monest, if not the com-
monest large bivalve of,
the New England, Long
Mactra sotidissima. Island, and New Jersey |

PELECYPODS 447

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 isa fragile V-shaped car-
dinal tooth, which is generally broken away in forcing open the valves;
the lateral teeth are long and thin, and striated on their receiving sur-
faces. 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 south-
ward to Brazil. Passing from New Jersey to Hatteras, Mactra soli-
dissima 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 Flor-
ida 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
Paget It is epee and is covered with 2 oy —

rown epidermis; the hinge is strong, with deep alain alia:
cartilage fossette and a V-shaped marginal tooth. seamen
The laterals are long and slender. The animal has a strong foot
andtwo slender, long siphons which are yellow in color.

Genus Reta

R. (Labiosa) canaliculata. In this species the cartilage fossette
is the same asin 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 Reta 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 externalribs. 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 VENERIDE

In many respects this is the most distinguished pelecypod fam-
ily. ‘It is the largest in number of genera and species, is of
world-wide distribution, and supplies to hungry man a number

448 MARINE INVERTEBRATES

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 Veneride 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 andfolded. There is a compactness and well-regu-
lated arrangement of the organs in the Veneridw, 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 Veneridw 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 Ameri-
can 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 “ Lit-
tle 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 exten-

PELECYPODS 449

sively gathered in the estuaries from Cape May to Cape Cod. Men
armed with rakes drift about in small boats and fish the sluggish crea-
tures up out of the mud. They will live for many days out of water if
kept in acool 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 for-
ward, the heart-shaped lunule, the external ligament, the concentric sculp-
turing of growth-lines, the pure-white interior (with occasionally violet
zones about the
muscle-secars and
margin), the three
stout cardinal teeth,
the — sharp-angled
pallial sinus, and the
ventral margin fine-
ly 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, increas-
ing in size and bulk
as it meets the a
warmer waters of Venus mercenaria, typical form.
theGulfStream. 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. .

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 cardi-
nal teeth and no laterals. The lunule is heart-shaped; the pos-
terior 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.)

29

450 MARINE INVERTEBRATES

Genus Cytherea

C. (Catlista) 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 porcela-
nous 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 ten-
derness, but it has a peppery taste. (Plate LXXXII.)

Genus Dosinia

There are two species of this very graceful genus of Veneride 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
arevery gracefully sculptured in fine, regular, impressed, concentric strie,
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 charac-
teristic 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.)

‘Genus Tivela

The coast of California is also favored by the Veneride, a num-
ber of large species belonging to several genera being present.

fT. 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

PLATE LXXXII.

Venus cancellata. Cytherea (Callista) gigantea.
Cytherea (Callista) maculata. Dosinia discus.

PLATE LXXXIII.

Tivela crassatelloides, one half natural Tapes laciniata, one half natural size.
size. Chione simillima.
Chione succincta.

PELECYPODS 451

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 liga-
ment; 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 can-
cellata, 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 LXXXIIL.)

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 LX XXIII.)

C. fluctifraga has broad but flatter or well-rounded (not sharp) con-
centric 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 Veneride. 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 sinusis deep. 7. 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 aaa 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 byssifer-
ous in this genus. (Plate LX XXIII.)

452 MARINE INVERTEBRATES

Genus Saxidomus

S. nuttallii. The last of the larger west-coast Veneride 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-look-
ing, 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 PETRICOLIDE

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. Al-
though this creature is allied to the Veneride, the degree
nh of mantle fusion present is much greater, leaving in this

Win case only a fairly long slit through which the foot may
i protrude. The shell is very dissimilar to that of any of

the Veneride, and in many respects, judging from a
conventional standard, is a remarkable form. It is ex-
ceedingly thin, is of a chalky texture, gapes widely pos-
teriorly, 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.
Petricotaproua. Length one and a quarter to two and a half inches;
formis. 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 en-
trance of its burrow or in retreating far out of sight within its depths.
Its siphons aretipped with a dark or drab color asa 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.

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 sculp-
turing are frequently reduced and sometimes are quite obsolete; but
the shell has the chalky, thin texture that is characteristic of the genus.

PELECYPODS 453

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 Petricolide. They are con-
sidered further on, under the name of Pholadide.

FAMILY CARDIDE
Genus Cardium

This is another important family of the Pelecypoda, which,
with the Veneride, the Mactride, and the Tellinide, 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 Cardiwm—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 Cardiwm is obviously not a deep-burrowing genus;
but it does partially bury itself in soft semi-liquid sand. Its pro-
gression is effected by leaps which it is enabled to make by reach-
ing 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 some-
what flatly depressed. The thirty-three to thirty-seven regularly dis-
posed, broad, radiating ribs; the regularly crenulated margins; the
yellowish-brown color garnished with transverse rows of chestnut or

454 MARINE INVERTEBRATES

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. levigatum. 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 Levicardium). It oceurs 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. levigatum 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,
Cardium mortom, showing zigzag lines of dark fawn-color upon the pale-
oxvondedanitasl: yellowish background of the smooth exterior sur-
face of the shells are a noticeable feature. The largest specimens mea-
sure an inch in length and nearly the same in height. The long cirri
upon the siphons are striking.

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.)

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
Levicardium. 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,

a

So : Patil

PLATE LXXXIV.
1, Cardium magnum, much reduced. 4, Cardium substriatum, enlarged.
2, Cardium isocardia. 5, Cardium corbis (young specimen).
3, Cardium levigatum. 6 Glvcimeris generoga.

PELECYPODS 455

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 brown-
ish ; 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 in-
ches.(Plate LXXXTV.)
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 yellow-
ish-brown epidermis covers the shell and bristles into a sort of fringe upon
the sharp edges of the ribs. C. islandicwm 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. pinnulatumis 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 mol-
lusks of small size. There are twenty-six slightly rounded
: ribs, with deep linear grooves between them. Upon the ribs,
Cardiwm especially in the posterior portion of the shell, are arched

* seales, 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 exceed-
ingly lively and able to make rapid progress over gravelly bottom by exe-
euting sudden leaps. It has a long, recurved, very strong foot, and its
movements are effected as described above. Itis abundant at Bar Harbor.

Cardium islandicum.

456 MARINE INVERTEBRATES

FaMILY MYIDE

Genus Mya

In this family we encounter, rather suddenly, some new fea-
tures 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 Veneride, in the Tellinidw, 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. —

M. arenaria. This is the common “ soft-shell clam” of New Eng-
land. 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, peb-
bly, 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 si-
phons projected into
the water. When
the water recedes,
Mya draws in its si-
phonsand awaits the
return of the tide,
Mya arenarva, every now and then

PELECYPODS 457

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

Mya arenaria, showing extended animal.

chowders and believed their flesh to possess valuable curative proper-
ties. 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, ete. These clams feed only on
sand.” What marvelous digestive powers!

FAMILY soLENIDE

In this family are included the long, slender bivalves com-
monly 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. Occasion-
ally 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

Ensis direcius, showing extended animal: 1, foot ; 2, siphons ; 3, papillx, enlarged.

good way to catch one is to approach his burrow carefully,
and then plunge a spade obliquely down below him, thereby

458 MARINE INVERTEBRATES

cutting off his retreat. So tenaciously will they cling to the sand
by expanding the muscular foot that the shell may be pulled en-
tirely off the body before they will let go.

Genus Einsis

E. directus (Solen ensis, Ensis americanus).
The common species upon the New England and
Jersey coasts. The footislong, 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 con-
fusing, 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 up-
per 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 de-
scent into the sand is very interesting. First ex-
tending 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 en-
ables it to draw down its shell. By quick repe-
tition of this process Ensis can get out of sight in
a remarkably sudden manner.

Genus Solen

S. viridis. A smaller species, about two inches
in length, and with a nearly straight light-green
a” Itis often abundant from New Jersey south-
ward.

Ensis directus. 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.

PELECYPODS 459

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

SS S=a55
SS ENR

Tagelus gibbus, showing extended animal.

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, sepa-
rated 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 yellow-
ish epidermis, which, passing the
ventral margin, appears to become
continuous nae the ee nee man-
SUREATer tle-edge. ere is no other species
ne ne north of Hatteras with which this
could be confounded. The double entrance to the burrow, which may
be discovored about low-tide mark, is unique. JT. gibbus is a good spe-
cies to examine for the crystalline stylet in the digestive tract.

FAMILY GLYCIMERIDE

Genus Glycimeris

G. generosa. A large shell of the Pacific coast, occurrimg 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

460 MARINE INVERTEBRATES

united siphons, protected laterally at their larger end by two white,
widely gaping valves. The very small pedal opening in the line of
mantle juncture indicates a very small foot. (Plate LXXXIV.)

FAMILY PHOLADIDE

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 inter-
esting. It is found in holes gouged out of solid rock or out of
pieces of wood; sometimes, like Petricola, it may be found exea-
vating 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 man-
ages 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 bur-
row 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

PELECYPODS 461

nevertheless thousands of them are destroyed by predatory star-
fishes, who know how to get at their victims. The restless crus-
taceans, ever on the outlook for a meal,
often nip the siphons of the rock-dwell-
ers, and a kind of worm sometimes
attacks them, and, destroying the ani-
mal, 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 abun-
dant north of Hatteras. In Florida it bur-
rows deep in sand as well as in wood or
rock. On account of its white color and
suggestive shape and sculpture, it has re-
ceived the popular name of ‘“angel’s-
wings.” It grows to a length of seven or
eight inches.

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.

P. californica.
A Californian Pho-
las. The shell is
about three inches in
length, and resem- Pholas costata.
bles in all features ,
and habits the Pholas of the east coast. Differ-
ences in the shell indicate that it is a distinct
species.

Pholas truncata, GENUS Zirphea

Z. crispata. A species of Northern rarlge, 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 pos-
terior area is smooth. This conchological feature of the genus is very

462 MARINE INVERTEBRATES

curious; it may be observed also in several deep-sea genera and in cer-
tain 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 tena-
cious clay. Length two to four inches.

FAMILY TEREDINIDE

Genus Teredo

T. navalis. This species is worm-
like in form, but
it has a small bi-
valve shell at the
larger end, and
near the anterior
extremity two
caleareous ap-
pendages called
pallets, beyond
which extend two
siphons. Along
the surface of the
scene is secret- 5
ed a continuous Zirphea crispata.
shelly tube which eat:
lines the burrow. This mollusk, commonly called
the “ ship-worm,” is exceedingly destructive, per-
forating 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 to-
gether 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 bur-
rows. 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.

There are three other species of Teredo and one
af the genus Ales on our Northern shores ij

oy Mala in L: navalis is, however, the most common an

oe pee oes peti most destructive. In Southern waters there are

T, tube; V, valve of shell. many other forms of these boring mollusks.

PELECYPODS

FAMILY PANDORIDE

Genus Pandora

463

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 mus-
eles, and a fairly large tongue-shaped
foot. The shell is nacreous, rounded
anteriorly, and produced posteriorly
into a sort of upturned tip which gapes

Pandora trilineata,

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.

TABLE SHOWING THE CLASSIFICATION OF THE CEPHALOPODS
DESCRIBED IN THIS CHAPTER

CLASS CEPHALOPODA

Subclasses Orders Genera Species
Tetrabranchiata Nautilus
Octopus
OCTOPODA { Argonne ree
Dibranchiata Spirula
DECAPODA § Ommastrephes 0, illecebrosus
( Sepia L. Pealet
Loligo ; 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 be-
longing 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, dart-
ing 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

464

CEPHALOPODS 465

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 en-
deavor to hide themselves from view. On bright moonlight
nights squids often go ashore in vast numbers, and perish within
afew 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 advan-
tage 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 govern-
ments for. many years.

The range in size among the species of this class is very re-
markable. 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 power-
ful 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-
30

466 MARINE INVERTEBRATES

fish, 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 Cephalop-
tera, 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. ‘Whale-
men 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

CEPHALOPODS 467

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 (chro-
matophores). There are sets of chromatophores containing differ-
ent 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 ani-
mal. In swimming it assumes the color of its surroundings.

Another curious means of protection possessed by the dibran-
chiate 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 branchie, 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;

468 MARINE INVERTEBRATES

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. Nau-
tilus 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

The second subclass, the Dibranchiata, is characterized by two
branchie and two auricles. The main part of the foot is divided
into eight or ten long arms provided with numer-
ous 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, Omma-
strephes, 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, ex-
cept when needed for
Argonauta argo, female removed from shell. prehension.

ane C Usd dH RAAT ETL IONS

CEPHALOPODS 469

GENUS Argonauta

A. argo. In this species, the paper-nautilus, the shell, which is pos-
sessed only by the female, is not chambered. The animal rests in the
shell, but has no or-
ganic connection
with it other than by
the membranous ex-
pansions at the ex-
tremities of the two
dorsal arms, which
secrete it and hold it
in place. The pur-
pose of the shell is
to hold and protect
the eggs.

Genus Loligo

L. Pealei. In this Argonauta argo, side view of shell.
species the body is
cylindrical, tapers to a point, and has a fiat 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.

Genus Ommastrephes

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 ex-
panded. 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

Loligo Peatei fe- : : :
“aue6 Agen vie. used so extensively in the Banks fishery as bait. It

470 MARINE INVERTEBRATES

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.

¥

Ommastrephes illecebrosus, young
male; ventral view.

VU

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)

Suborders Genera

Appendicularia

Order THALIACEA

(Free-swimming Tunicata, without caudal appendages ; single or in colonies ; muscles
of body-wall arranged in complete or wn interrupted ring-like bands)

CYCLOMYARIA
(Cask-shaped bodies with complete rings |
of muscular bands ; oral and atrial Doliolum
apertures «at opposite ends of the
body) |
HEMIMYARIA
( Spindle-shaped bodies ; muscular bands )
in incomplete rings; oral and atrial ) Salpa
apertures subterminal) (
PYROSOMATA
(Hollow cylindrical colonies ; zodids em-
bedded ina gelatinous wall ; oral aper- Pyrosoma
tures open on the outer, atrial apertures
open on the inner surface of cylinder)

472

CHORDATA

Suborders Genera
Order ASCIDIACEA

473

Species

(Mostly fixed Tunicata ; single or in colonies ; tests of considerable thickness)

Motgula

ASCIDIA SIMPLICES
(Possess distinct tests ; usually perma- } Cynthia
nently fixed) .

Boltenia
Ascidia

ASCIDIA COMPOSITE
(Fixed colonies ; the zodids embeddedina ) Botryllus
common gelatinous material ; without ) Amaracium
separate tests)

M. manhattensis
) M. petlucida

M, arenata

C. pyriformis

C. partita

C. carnea

B. clavata

A. amphora
; A. callosa

B. gouldii
A. pellucidum

CHORDATA

CLASS UROCHORDA or TUNICATA

HE 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 ani-
mals because in the larval stage they have a notochord ; this disap-
pears, 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 dis-

tributed, and occur at all depths. (Plate LXXXV.)
474

TUNICATES AND ASCIDIANS 475

Genus Salpa

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 indi-
viduals are about an inch long, and have two long
processes at the posterior end. These single ani-
mals reproduce by budding, and form series of indi-
viduals in small chains, the ani- mals being arranged
in tworows. 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 sin- gle egg, which becomes a
single Salpa, and this again, like its grandmother,
reproduces by bud- ding. Thus the animals are
alike only in alter- nate generations. The natural-
ist Chamisso, who discovered the relationship be-
tween the two forms, expressed it as follows: a
Salpa mother is not like its daughter or its mother,
butresembles chain. its sister, its grandmother, and its grand-
daughter. The single zodids 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 ser-
pentine 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-swim-
ming, 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

476 MARINE INVERTEBRATES

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 extenaed; hard,
velvety, whitish surface, with pink cheeks; orifices on prominent pro-
tuberances 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, resem-
bling the flower of lady’s-slipper (Cypripedium) ; two cross-shaped ori-
fices 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.)

GEenus Ascidia

Test gelatinous or cartilaginous; attached; it grows in bunches
under stones at low-water mark. Sometimes it is variously col-

hots, Uetaeenteeetedb ol

PLATE LXXXY.

ASCIDIANS.

1, Ascidia callosa.

2, Botryllus Schlosseri.
3, Cynthia pyriformis.
4, The same, enlarged.

9, Cynthia echinata.

Cynthia placenta.
Glandula fibrosa.
Cynthia condylomata.
Boltenia clavata.

TUNICATES AND ASCIDIANS 477

ored, 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 ; sub-
stance 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

XEN) Found at low tide adhering to stones and shells. (Plate

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 zodids are in some cases dotted irregu-
larly 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 zodids 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
zodids are purple, marked with other colors ; again the arrangement is
quite different.

Genus Amarecium

A, pellucidum. A massive compound ascidian, smooth, translucent,
and gelatinous, which forms large, hemispherical, complex, irregular
masses six inches or moreindiameter. Itis 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
zoids, sometimes an inch long, are grouped. These masses are so abun-
dant in some places that they cover the bottom for considerable spaces.
They are found in deep water from Cape Cod to North Carolina.

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.
Acmza, 9, 309, 312.

A. mitra, 324, 357.

A. patina, 324, 357-

A. testudinalis, 41, 42, 324,

348, 348, 356.
A. testudinalis, var.
veus, 324, 357.

Acmeidz, 324, 356.
Acontia, 145.
Acorn-shell, 254.
Actiniaria, 141, 142, 148, 144.
Actinozoa, 112, 115, 141, 142.
Adamsia palliata, 144, 267.
Adductor muscles, 302, 413,

al-

417.
ZEolididz, 324.
Eolis, 41, 42, 309, 324, 354.

4E. papillosa, 324, 354.
Equoreide, 116, 128.
tea, 188, 194.

4. 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.
Albunza, 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, 151.
Aleutian province, 311.
Alga, 25, 48, 62, 76.

Botanical facts about, 25.

Alternation of generation, 120,
121.

Amarececium, 473, 477.

A. pellucidum, 473, 477.

Auulaers 201, 202, 205, 214,
8,
Ambulacral groove, 205.

Ossicles, 205.

Zones, 201, 202, 205, 218, 229.
American division, 24.
Amphictenidz, 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.
Ampulle, 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,

2i.
Annelida, 305.
Annulata, 159, 161, 164, 170.
Anomia, 405, 424.

A. aculeata, 405, 425.

A. lampe, 405, 425.

A. simplex, 405, 424.
Anomiidz, 405, 424.
Anomura, 240, 264.
Antenne, 243, 246, 258.
Antennules, 243, 246, 258.
Antheneidz, 204, 209.
Anthomedusza, 116.
Aperture, 302.

Apex, 343.
Aphrodite, 161, 174.

A. aculeata, 161, 174.
Aphroditidz, 161, 172, 173.
Aplacophora, 300, 321, 323.
Aplysella violacea, 105.
Aplysia Wilcoxii, 352.
Aplysiide, 324.

Apoda, 228, 233.
Appendicularia, 472.
Arabella, 161, 179.

A. opalina, 161, 179.

Arbacia, 217, 222.

479

A. punctulata, 217, 222.
Arbaciade, 217, 222.
Arca, 310, 405, 425.

A. noz, 405, 426.

A. pexata, 405, 425.

A. ponderosa, 405, 426,
Arcachon, 434.
Architeuthis, 465.
Arcidz, 405, 425.

Arctic province, 309.
Arctica, 406, 441.

A. islandica, 406, 441.
Arenicola, 162, 172, 184.

A. marina, 162, 184.
Arenicolide, 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. composite, 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.
Astacoide, 240, 261.
Astarte, 309, 406, 440.

A. castanea, 406, 441.

A. undata, 406, 441.
Astartidz, 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.
Asteriidz, 204, 212.
Asterina, 204, 210.

A. folium, 204, 210.

A. miniata, 204, 211.
Asterinidz, 204, 210,
Asteroidea, 200, 204, 205.
Astrea, 141, 146, 147, 148,

480

Astrangia, 141, 150.

A. danaé, 18, 141, 150.
Astropecten, 204, 209.

A, articularis, 204, 209.
Astropectinidge, 204, 208.
Astrophyton, 213, 215.

A. Agassizii, 213, 215.
Astyris gausapata, 326, 389.
Asymmetrical, 328,
Aurelia, 133, 137.

A. flavidula, 183, 137.
Auricula, 231.
Auriculata, 201.
Avicula, 405, 431.

A. atlantica, 405, 431.
Avicularia, 190, 193.
Aviculidz, 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.
Bangiacez, 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.
Bopyride, 292.
Boreal, 23.
Boring amphipod, 290.
Boring-sponges, 105.

* Bostrychia, 177, 89.

B. rivularis, 77, 89.
Botanical facts about alge, 25.
Botryllus, 473, 477.

INDEX

B. gouldii, 473, 477.
Bougainvillea, 124.

B. superciliaris, 116, 124.
Box-crab, 287.
Brachyura, 241, 258, 272.
Brain-corals, 146.
Branchiz, 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, Ig1.

Buccal mass, 302, 317.
Buccinidz, 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.

Bullidz, 324.
Butterfly-shells, 323.
Byssus, 415, 426, 432,

Cc

Caberea, 188, 195.

C. Ellisii, 188, 195.
Cake-urchins, 218, 224.
Calappa, 241, 287.

C. flamma, 241, 287.
Calappida, 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, 825, 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, go.

C. americanum, 78, go.

C. Baileyi, 78, gr.

C. byssoideum, 78, gI.

C. floccosum, 78, gr.

C. Pylaiszi, 78, gt.

C. seirospermum, 78, I.
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.
Cancellariidz, 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.
Cancroide, 241, 277.
Caprella, 8, 242, 291.

C. geometrica, 242, 291.
Capulidz, 325, 369.
Carapace, 243, 246.
Carcinides, 241, 274.

C. mzenas, 241, 274.
Carcinus mznas, 41, 274.
Cardiida, 407, 453-
Cardita, 406, 440.

C. borealis, 406, 440.

C. floridana, 406, 440.
Carditidz, 406, 439.
Cardium, 310, 311, 407, 410,

418, 453.

C. corbis, 407, 454.

C. elatum, 407, 454.

C. islandicum, 407, 454.

C. isocardia, 407, 454.

C. levigatum, 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.
Cassidide, 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 VIIL

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.
Cenobitidz, 240, 268,
Cephalic, 248, 246.
Cephalopoda, 301, 315, 320,

321, 464.
Cephalothorax, 243, 246, 272.
Ceramiez, 78, go.
Ceramiunm, 27, 43, 78, g2.

C. diaphanum, 78, 93.

C. fastigiatum, 78, 93.

C. rubrum, 78, g2.

C. rubrum, var. proliferum,

78, 93.
C. rubrum, var. secunda-
tum, 78, 93.

C. strictum, 78, 93.

C. tenuissimum, 78, 93.

C. tenuissimum, var. pa-

tentissimum, 78, 93.
Cerata, 353.
Cerebratulus, 160, 170.

C. angulatus, 160, 170.
Cerianthus, 144,
Cerithidea, 326, 375.

C. sacrata, 326, 375.

C. scalariformis, 326, 375.
Cerithiidz, 326, 373.
Cerithium, 326, 374.

C. floridanum, 326, 374.

Cc. minimum, 326, 374.

Cc. 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.
Chete, 173.
Chetangiez, 76, 80.
Chztobranchus, 161, 182.

C. sanguineus, 161, 182.
Chzetomorpha, 51, 53.

C. zrea, 51, 53.

C. linum, 51, 54.

Cc. melagonium, 51, 53.

C. picquotiana, 54.

C. tortuosa, 53.
Chetopoda, 161, 171.
Chalinopsilla, 100, 107.

C. arbuscula, 100, 107.

C. oculata, 100, 107.
Chameedoris, 51, 56.

C. annulata, 51, 56.
Champia, 77, 85.

Cc. parvula, 77, 85.
Charybdeza, 133, 137.

C. marsupialis, 133, 137.
Cheilostomata, 188, 194.
Chelee, 248, 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. czeca, 242, 294,

31

INDEX

C. entomon, 242, 294.
Chiton, 9, 309, 322.

C. albus, 323.

C. apiculatus, 323.

C. ruber, 41, 323.

C. spinosus, 322.
Chitonida, 312, 322.
Chlorophycez, 28, 47, 51.
Chlorostoma, 312, 325, 362.

C. brunneum, 325, 362.

C. funebrale, 325, 362.
Choanocytes, 102.
Choanoflagellata, 102.
Chondria, 77, go.

Cc. cpeyphyila, TT, go.

C. striolata, 77, go.

C. tenuissima, 77, go.
Chondrospongie, 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,

Chordariacee, 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.
Cidaridz, 217, 222.
Cidaris, 217, 222.

C. tribuloides, 217, 222.
Ciliary flames, 164,
Cinereous, 302.

Cirolana, 242, 292.

C. concharum, 242, 292.
Cirratulidaz, 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.

481

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.

Codiacez, 51, 59.
Codium, 51, 59.

C. tomentosum, 61, 59.
Coelenterata, 111, 112, 113.
Ccelopleurus, 217, 222.

C. floridanus, 217, 222.
Coenosare, 118,
Coffee-shells, 379.
Collecting, 6.

And preserving seaweeds, 15.

At Bar Harbor, 4o.
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.
Columbellidz, 326, 388.
Columella, 302, 344.
Comatuila, 234, 235. “5
Comb-jetis.o, 244, 115, 155.
Communal life, 121.
Conceptacles, 72.

Conchs, 377.
Conch-shell, 376.
Concrescent, 302.
Confervacee, 26, 51, 53.
Conidz, 327, 401.
Connostome2, 133.
Conus, 318, 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.
Corallinez, 78, 95-
Corallite, 146.

Corallum, 146.

Corals, 112.

Cordate, 302.

Cormophytes, 25.
Cornacuspongia, 100,
Coronula diadema, 255.
Corymorpha pendula, 116.
Coryne, 116, 123.

C. mirabilis, 116, 123.
Cosmocephala, 160, 170.
C. ochracea, 160, 170.

Coste, 302.
Cowry-shell, 377.
Crabe enragé, 274.
Crabs, 244, 247, 272.

Blue, 275.

Box-, 287.

Fiddler-, 241, 282,

Ghost-, 282,

Green, 274,

Hermit-, 264.

Kelp-, 286,

482

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, 2617

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. _

©. canguinolenta,, 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.
Cryptonemiacez, 78, 94.
Cryptozonia, 204, 211.
Crystalline stylet, 302, 341.
Ctenidia, 302.

Ctenodiscus, 204, 208.

Cc. corniculatus, 204, 208.
Ctenophora, 112, 115, 154, 155.
Ctenostomata, 189, 197.
Cubomeduse, 133, 137.
Cucumaria crocea, 231.

C. laevigata, 231.
Cumacea, 242, 288.
Cutleria, 63, 71.

C. multifida, 63, 71.
Cutleriacez, 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.
Cyanophycee, 28, 48, 49.
Cyclomyaria, 472.

Cyclops, 239, 249, 250.

INDEX

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.
Cypreza, 326, 334, 377.

C. aurantia, 377.

C. exanthema, 326, 378.

Cc. moneta, 378.

C. spadacea, 326, 379.

C. spurca, 326, 378.
Cypraidz, 326, 377.
Cypridina, 238.

C. islandica, 441.
Cyprinidz, 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.
Dactylozodids, 129.
Daphnia, 238.

Dasya, 77, 79, 89.

D. elegans, 177, 89.

D. plumosa, 77, 89.
Dasycladacez, 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.
Delesseriez, 77, 85.
Dendronotidz, 324,
Dendronotus, 41, 42, 324, 353.

D. arborescens, 324, 353.
Dentalidz, 327, 402.
Dentalium, 268, 327, 328, 404.

D. dentale, 327, 403.

D. hexagonum, 327, 403.

D. pretiosum, 327, 403.
Dermal branchiz, 208.
Desmacidonide, 100.
Desmarestia, 15, 62, 66.

D. aculeata, 43, 62, 66.

D. ligulata, 62, 67.

D. viridis, 62, 66.
Desmarestiacee, 62, 66.
Desmids, 33.
Desmosticha, 217, 221.
Devil’s pocket-books, 12.
Dextral, 303, 345.
Diadema, 217, 222.

D. setosum, 217,222.
Diadematida, 217, 222.
Diastopora, 188, 194.

D. patina, 188, 194.
Diastylis, 242, 288.

D. quadrispinosus, 242, 288,
Diatocardia, 300, 324, 356.
Diatomacee, 38,
Diatomaceous 002e, 21.
Diatoms, 21, 32.

Green, 435.
Dibranchiata, 301, 464, 468.
Dictyosiphon, 62, 67.

D. foeniculaceus, 62, 67,
Dictyosiphonacez, 62, 67.
Dictyota, 63, 70.

D. dichotoma, 68, 70.

D. fasciola, 63, 70.
Dictyotacez, 63, 70.
Diopatra, 10, 161, 178.

D. cuprea, 161, 178.
Diploria, 141, 148.

D. cerebriformis, 141, 148.
Discomeduse, 133, 137.
Distribution of alge, 30.

Of animal life in the sea, 23.
Doliidz, 326, 379.
Doliolum, 472,

Dolium, 310, 326, 379.

D. galea, 326, 379.

D. perdix, 326, 379.
Donacida, 406, 445.
Donax, 10, 406, 445.

D. californicus, 406, 445.

D. variabilis, 406, 445.
Doridide, 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.
Dromidez, 240, 264.
Dulse, 38.
Dumontiez, 78, 94.

E

Ears, 247, 435.

Of corn, 12.
Echidnocerus, 240, 270.

E. cibarius, 240, 270.

E. foriminatus, 240, 271.
Echinanthide, 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.
Echinasteride, 204, 211.
Echinida, 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.
Ectocarpacez, 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, ror, 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.
Elachistacee, 67.
Elytra, 173.
Embryology, 20,
Enceeliacez, 62, 65.
Encope, 217, 226.

E, michelini, 217, 226.
Endendrium ramosum,

Plate XLI.

Endoderm, rox, 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, 61, 55-

E, intestinalis, 51, 55.

E. lanceolata, 51, 56.
Entomostraca, 238, 249.
Entoprocta, 189, 198.
Ephyrula, 136.

Epialtus, 241, 286.

. productus, 241, 286.
Epidermis, 303, 345, 347.
Epimera, 243.
Epipodite, 243.
Epistoma, 243.
Epizoanthus

* 267.
“Equilateral, 418.
Equivalve, 418.

Erect Polyzoa, 103.
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,
Eugorgia aurantica, Plate

XLVI

301,
Plate

americanus,

Eulamellibranchiata,
406, 420, 438.

Eunicea__ lugubris,
XLVIL

Eunicide, 161, 178.
Eupagurus kroyeri, 267.
E. prideaux, 267.
E. pubescens, 267.
Eupanopeus, 241.

INDEX

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. adriat-

ica, 100, 108.
E. officinalis, var. dura,
100, 108.
E. officinalis, var. mollis-
sima, 100, 108.
E, officinalis, var. rotunda,
100, 108.
Euspongine, roo.
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.
Fasciolariidz, 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.
Fissurellidz, 324, 357.
Flagellate Infusoria, roz.
Flatworms, 164.

Floridez, 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.

Fucacee, 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.

483

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,

Gelidiez, 76, 80,
Gelidium, 76, 80.

G. corneum, 76, 80.

G. Coulteri, Plate XVII.
Generic name, 28,

Genus, 20.

Geographical distribution, 308.
Gephyrea, 171, 1&5.
Geryonopside, 116, 128.
Ghost-crab, 282.

Giant crab of Japan, 244.
Gigartina, 28, 76, 81.

G. mamitllosa, 74, 81.

G. microphylla, 76, 81.

G. radula, 76, 81.

G. spinosa, 76, 81.
Gigartinacez, 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.
Gloiosiphoniez, 78, 94.
Glove sponge, 104.
Glycera, 161, 180.

G. americana, 161, 180.

G. dibranchiata, 161, 189.
Glyceridz, 161, 179.
Glycimeridz, 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.
Grapsidz, 241, 281.

Grass sponge, 104.
Grateloupia, 78, 94.

484

G. Cutleria, 78, 94.
Grateloupiez, 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.
Gymnolemata, 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.
Haliotide, 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.
Harmothoé, 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.
Heliasteridz, 204, 212.
Helipora, 147.
Helmet-shells, 380.
Helminthocladiee, 76, 79.
Hemigrapsus, 241, 281.

H, nudus, 241, 281.

H. oregonensis, 241, 281.
Hemimyaria, 472.
Herbarium, 17.
Hermit-crabs, 12, 258, 259, 264,

362,

Heteroceela, 100.
Heterograpsus nudus, 281.

H. oregonensis, 281.
Heterorrhaphide, 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.
Hippide, 240, 268.
Hippoconcha, 240, 264.

H. arcuata, 240, 264.
Hippospongia, 100, 108.

INDEX

H. canaliculata, 100, 108.

H. canaliculata, var. fla-
bellum, 100, 109.

H. canaliculata, var. gos-
sypina, 100, 108.

H. equina, 100, 108.

H. equina, var. agaricina,
108.

H. equina, var. cerebrifor-
mis, 100, 108.

H. equina, var. dura, 108.
H. equina, var. elastica,
100, 108. :
H. equina, var, meandri-

formis, 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.
Homorrhaphide, 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,
20,

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, 204.

I. wosnesenskii, 242, 294.
Idyia, 154, 157.

I, cyanthina, 154, 158.

I, roseola, 154, 157.
Inarticulata, 188.
Infusoria, 21, 101.
Interambulacral areas,

02, 218.

Introvert, 186,
Iridza, 76, 82.
Isopoda, 242, 291.
Isopods, 12.

201,

J

Janthina, 325, 364.

J. fragilis, 325, 365.
Janthinide, 325, 364.
Jellyfishes, 7, 44, 112, 115, 119,

I

34-
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.
Laminariacee, 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.
irda 238.

eptogorgia Agassizii, Plate

syle :

L. rigida, Plate XLVII.
Leptoliniz, 116, 121.
Leptomeduse, 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, 2092.
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.
Lithodidz, 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.
Littorinidz, 325, 338, 370.
Livona, 325, 362,

L. pica, 268, 325, 362.
Lizzia, 120.

Lobata, 154, 156.

TAREIEES: 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.
Lucinidz, 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. zstuarii, 50.

?

INDEX

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.
Mactridz, 406, 446.
Madreporic plate, 201, 203, 206,

218.
Maiidz, 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.
Marginellida, 327, 399.
Marine invertebrates, 97.
Maxille, 243, 246, 258.
Maxillipeds, 243, 246, 258.
Meckelia, 160, 169.

M. ingens, 160, 169.

M. rosea, 160, 169.
Mediaster, 204, 209.

M. zqualis, 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, ror, 118.
Mesogleea, 62; 68.

M. divaricata, 62, 68.

M. virescens, 62, 68.

485

Metalia, 217, 227.

M. pectoralis, 217, 227.
Metameres, 243.
Metapodium, 376.
Metazoa, ror.
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.
Meera levis, 2go.

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, $29, 333.
Mud-crabs, 12.

Muddy shores, 12.
Multivalve, 307.
Murex, 326, 331, 382.

M. fulvescens, 383.

M. pomum, 3826, 383.

M. rufus, 326, 382.

M. tenuispina, 343, 347.
Muricea_ specifera, Plate

XLVI.

Muricidz, 326, 381.
Muricing, 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.
Myide, 407, 456.
Myrionema, 62, 68.
Mysis, 239, 257.

M. sternolepsis, 239, 257.
Mytilidz, 405, 426.
Mytilus, 41, 309, 405, 426.

M. californicus, 405, 428.

486

M. edulis, 42, 43, 287, 405,
427, 428.
M. hamatus, 405, 428.

N

Naming of plants, 28.
Nanomia, 130.

N. cara, 117, 130.
Narcomedus@, 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.
Nassidz, 327, 390.

Natica, 311, 325, 334, 367.

N. canrena, 325, 368.

N. clausa, 325, 368.

N. heros, 367. ~
Naticidz, 325, 366.
Nauplius, 248, 251.
Nautilus, 328, 467.

Navicula ostrearia, 435,
Nekton, 23.
Nemalion, 76, 79.

N. multifidum, 76, 79.
Nemalionacez, 76, 79.
Nemathelminthes, 159, 161,

170.
Nematoda, 161, 170.
Nematophore, 118.
Nemerteans, 167.
Nemertes, 160, 169.

N. socialis, 10, 169.

N. viridis, 160, 169.
Nemertinea, 160, 167.
Neopanopeus, 241.

W. texana, 241, 281.
Nephridia, 319.
Nephridium, 303.
Nephthydidez, 161, 177.
Nephthys, 161, 178.

N. ingens, 161, 178.

N. picta, 161, 178.
Nereida, 161, 176.
Nereis, 161, 176.

N. limbata, 161,177.

N. pelagica, 161, 177.

N. virens, 161, 177.
Nereocystis, 63, 70.

N. Litkeana, 35.
Nerine, 161, 181.

N. agilis, 161, 18r.

N. coniocephala, 161, 181.
Nerita, 325, 363.

N. peleronta, 325, 363.

N. tessellata, 325, 363.

N. versicolor, 825.
Neritidz, 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.
Nicothoé, 239, 250.

INDEX

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.

Nostocacee, 48.

Nucula, 309, 405, 422.

N. proxima, 405, 422.
Nuculida, 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.
Ocypodide, 241, 282.
Odontophore, 303.

Oliva, 10, 311, 313, 327, 334, goo.

O. literata, 327, 400.
Olivella, 10, 312, 327, 400.

O. biplicata, 327, goo.

O. boetica, 327, gor.

O. mutica, 327, 400.
Olividz, 327, 400.
Ommastrephes, 464, 468, 469.

O. illecebrosus, 464, 469.
Opercula, 193.

Operculum, 254, 303, 331, 355.
Ophiocoma, 213, 216.

O. zthiops, 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.
Ostreidz, 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-, 480, 481, 432.

P

Pacific faunal divisions.
Pacygrapsus, 241, 282.

P. crassipes, 241, 282.
Padina, 63, 71.

P. pavonia, 63, 71.
Paguridz, 240, 264.
Pagurus, 240, 267.

P. bernhardus, 240, 267.

P. longicarpus, 240, 267.

P. pollicaris, 240, 267.
Palzmonetes, 240, 260.

P. vulgaris, 240, 260.
Palzemon vulgaris, 260.
Pallial line, 203, 418,

Sinus, 303, 419.

Palps, 176, 416.
Palpus, 258.

Panamic province, 312.
Pandora, 407, 463.

P. trilineata, 407, 463.
Pandoridz, 407, 463.
Panopeus, 12, 28r.
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, 480, 431.
Pecten, 309, 405, 435.

P. equisulcatus, 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.
Pectinidz, 405, 435.
Pedal opening, 412.
Pedata, 228, 231.
Pedicellariz, 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.
Penzus, 240, 260.

P. brasiliensis, 240, 260.

P, setiferus, 240, 260.
Penicillus, 51, 58.

P. capitatus, 51, 58.

P, dumentosus, 51, 58.

P. Phoenix, 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.
Pentacerotidz, 204, 210.
Pentacrinus, 234, 235.
Pentacta, 228, 292.

P. frondosa, 43, 228, 232.
Pentagonasterida, 204, 209.
Pericardium, 341, 416.
Pericolpa, 133, 136.

P. quadrigata, 133, 136.
Peridiniez, 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.
Peromedus2, 133, 136.
Petricola, 407, 452.

P. carditoides, 407, 452.

P. pholadiformis, 407, 452.
Petricolidz, 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.
Phzophycee, 28, 61, 62.
Phanerogams, 25.
Phanerozonia, 204, 208.
Phascolosoma, 162, 186.

P, Gouldii, 162, 186.
Pholadidz, 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, 1g. -
Phyllitis, 62, 66.

- P. fascia, 62, 66.
Phyllodoce, 161, 175.

P. gracilis, 161, 175.
Phyllodocidz, 161, 175.

INDEX

Phyllolithodes, 240, 271.

P. pap ilosus, 240, 271.
Phyllonotus pomun, 382.
Phyllophora, 76, 81.

P. Brodizi, 76, 82.

P. membranifolia, 76, 82.
Phyllopoda, 238.
Phyllospora, 63, 73.

P. Menziesii, 63, 73.
Phylun, 19.

Phyncopodia helianthoides,
a

107.
Physalia, 131.

P. arethusa, 117, 131.
Pikea, 78, 94.

P. calitornica, 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.
Pinnotheriidz, 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,

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.
Polycheta, 161, 172.
Polycirrus, 161, 182.

P. eximius, 161, £82.
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,

160,

367.
P. heros, 3, 10, 44, 325, 343,

367.

P. lewisii, 325, 368.

P. recluziana, 325, 368.

P., triseriata, 325, 367.
Polyneé, 161, 174.

P. squamata, 161, 174.

P. sublevis, 161, 174.
Polyphemus, 238.

487

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,

17, 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.
Porcellanasteridz, 204, 208.
Porcellanide, 240, 269.
Porcupine Island, 42.
Porifera, 100, 101.
Porites, 147.

P. astrzaoides, Plate XLV.

P. furcata, Plate XLV.
Porocidaris, 217, 222.

P. sharreri, 217, 222.
Porphyra, 48, 78, 96.

P. laciniata, 78, 96.

P. vulgaris, 38, 78, 96.
Porpita, 132.

Portunidz, 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.

Protococcacee, 38,
Protococcus nivalis, 25, 33.
Protophyta, 21.
Protozoa, 21, 101,
Pseudolamellibranchiata,
301, 405, 420, 429.
Psilaster, 204, 209.
P. flora, 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.

488

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. hemastoma, 326, 387.

P. lapillus, 41, 42, 314, 326,

86

386.

P. lima, 326, 387.

P. patula, 326, 386.

P. saxicola, 326, 387.
Purpurine, 326, 385.
Pycnogonida, 242, 296.
Pycnogonida, 9.
Pylopagurus, 268.
Pyloric ceca, 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.
Reta, 406, 447.

R. canaliculata, 406, 447.
Ralfsia, 62, 65.
Ralfsiacez, 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.
Rhabdoceelida, 160, 167.
Rhabdonia, 77, 83.

R. Coulteri, 77, 84.

R. tenera, 77, 83.
Rhithropanopeus, 241.

R. harrisii, 241, 281.
Rhizocephala, 239, 256.
Rhizophyllidez, 78, 95.
Rhizostome, 133, 139.
Rhodactinia, 141, 145.

R. davidsii, 141, 145.
Rhodomela, 77, 89.

R. floccosa, 77, go.

R. larix, 77, go.

R. Rochei, 77, 89.

R. subfusca, 77, 89.
Rhodomelee, 77, 86.
Rhodophycez, 28, 76, 79.
Rhodophyllidez, 77, 83.
Rhodophyllis, 77, 83.

R. veprecula, 77, 83.
Rhodospermee, 79,
Rhodymenia, 77, 85.

R. palmata, 38, 42, 43, 77, 85.
Rhodymeniacee, 77, 84.
Rhodymeniez, 77, 85.
Ring-canal, 201, 203.

INDEX

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.
Sabellidz, 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.
Scalidz, 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, 2

Scutellidze, 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, 48, 114, 200, 203,
218, 220.

Sea-whips, 142, 152.
Sedentaria, 161, 180.
Segment, 243.
Segmented worms, t70.
Semostome, 133, 137.
Sense-organs, 135.
Sepia, 464, 467, 468.
Septibranchiata, 420.
Serpula, 162, 185.

S. dianthus, 162, 185.
Serpulidz, 162, 184.
Sertularia, 126.

S. argentea, 43, 116, 127.

S. cupressina, 116, 127.

S. pumila, 43, 116, 126.
SEEOULEHOnS, 8, 116, 120, 121,

126.
Sessile, 121, 126.
Sheep-crab, 285.
Sheepswool sponge, 104, 108.
Shell—

Butterfly-, 323.

Coffee-, 879.

Conch-, 377.

Cowry-, 877.

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. pygmzeus, 327, 394.

S. Stimpsoni, 327, 393.
Siphon, 304, 330, 334, 411.

nal, 412.

Branchial, 412.

Excurrent, 412.

Functional, 411.

Incurrent, 412.
Siphonalia, 327, 394.

S. kellettii, 827, 394.
Siphonea, 51, 56.
Siphonoglyphs, 143.
Siphonophora, 117, 120, 121,

1g0.
Siphonozodids, 150.
Siphuncle, 468.
Sipunculoidea, 162, 185.
Sipunculus, 162, 185.

S. nudus, 162, 185.
Skates, 12, 44.
Solaster, 204, 205, 211.

S. decemradiata, 204, 21z.

S. endeca, 204, 211.
Solasteridz, 204, 211.
Solen, 407, 458.

S. ensis, 3, 458.

S. rosaceus, 407, 458.

S. sicarius, 407, 458.

S. viridis, 407, 458.
Solenidz, 407, 457.

Solenogastres, 321.
Solenomya, 405, 423.

S. borealis, 405, 423.

S. velum, 405, 423.
Solenomyide, 405, 423.
Somite, 243.

Sow-bugs, 2gr.
Spatangoide, 217, 226.
Spatangoidea, 217, 226.
Species, 20.

Specific name, 28,
Sphacelaria, 62, 65.

S. cirrhosa, 62, 65.

S. radicans, 62, 65.
Sphacelariacez, 62, 65.
Sphzoplea annulina, 37.
Spheeridia, 219.
Sphzrococcee, 77, 84.
Sphzroma, 242, 293.

S. destructor, 293.

S. quadridentatur, 24°,

. 293-

Spicules, 102.
Spider-crabs, 241, 284.
Spines, 201, 205, 221.
Spionide, 161, 181.
Spire, 304.

Spirorbis, 8, 12, 162, 185.

S. borealis, 162, 185.
Spirula, 464, 467, 468.
Spirulina, 48, 49.

Sponges, 100, ror.
Spongia, 104.

S. graminea, 10g.
Spongide, 100.
Spongillidz, 104.

Spongin, ro2.
Spring-tides, 13, 15.
Spyridia, 78, g2.

S. filamentosa, 78, 92.
Squamariez, 78, 95.
Squame, 243.

Squids, 464.
Sguilla, 241, 288.

S. empusa, 241, 288.

Starfishes, 43, 114, 200, 203, 204,

205, 434.
Station and habits of the Mol-
lusea, 313.
Stauromeduse, 133, 136.
Stelospongine, 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.
Striz, 344.

Strobila, 135, 138.
Strombidz, 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.

INDEX

Stylochopsis, 160, 166.

S. littoralis, 160, 166.
Suberites, 100, 106.

S. compacta, 100, 106.
Suberitidz, 100.
Suborders, 29.
Subumbrella, 120.
Suckers, 201, 203.
Sun-jellies, 134, 138.
Suture, 304, 344. =
Swimming-bell, 120.
Swimming crabs, 241.
Syconidz, 100.
Syllida, 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 algw—
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.
Tellinidz, 406, 443.
Telson, 243, 247.
Tentaculocysts, 195.

489

Terebellide, 161, 182.
Teredinidz, 407, 462.
Teredo, 407, 462.

T. navalis, 13, 407, 462.
Terga, 254.

Terms used in describing Crus-
tacea, 243.

Echinoderms, 201.

Hydroids, 118.

Mollusks, 302.

Polyzoa, Igo.
Testaceous, 304.
Tetrabranchiata,

67.
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, 224.
Trachyline, 117, 120, 128.
Trachymeduse, 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.
Trochide, 325, 359.
Trochiscus, 325, 362.

T. norrisi, 325, 362.
Trophon, 409, 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.
Turbinellidz, 327, 394.

301, 464,

490

Turbinide, 325, 362.
Turbo, 325, 363.
T. castaneus, 325, 363.
T. castaneus, var. crenu-
latus, 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.
Udoteacez, 51, 58.
Ulothrix, 51, 53.
Ulva, 26, 28, 29, 61, 55.
U. lactuca, 51, 55.
U. latissima, 51, 55.
U. Linza, 56.
U. rigida, 55.
Ulvacez, 28, 51, 52, 53, 54.
Umbilicus, 304, 344.
Umbo, 304, 417.
Uneini, 180.
Univalves, 306, 307, 314.
Urochorda, 472, 474.
Urosalpinx, 11, 326, 383, 434.
U. cinerea, 314, 326, 383.
Uses of algae, 37.

Vv

Valoniacee, 51, 56.

Valve, 409, 416.

Varices, 304, 344, 347.
Vegetative reproduction, 27.

INDEX

Vellela, 131.

V. limbosa, 117, 131.

Velum, 134.
Velutina, 309.
Velvet sponge, 104.
Veneride, 406, 447.
Venous sinuses, 247.
Ventral surface, 201.
Ventricosa, 304.

Venus, 406, 410, 448.

V. cancellata, 406, 449.

V. mercenaria, 406, 448.

V. mercenaria, var. mor-

toni, 406, 449. y
Venus’s flower-basket, 102.

Girdle, 157.

Vermes, 163.
Vermetide, 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.

WwW

Walking crabs, 241.

Water-vascular system,
202, 206, 231.

West Indian division, 24.

Wharves and bridges, 13.

Whelks, 44.

Whorl, 304, 343.

Whorls, nepionic, 344.

201,

Worms, 159, 163.
Bristle-, 171.
Cheetopod, 172.
Clam-, 176.
Flat-, 164.
Nemertean, 167, 169.
Polycheete, 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. thracizformis, 405, 422.

Z

Zirphza, 407, 461.

Z.crispata, 407, 461.
Zoantharia, 141, 142.
Zoarium, 190, 192.
Zoéa, 248, 263, 273.
Zocecinm, 190, 192.
Zonaria, 63, 70.

Z. lobata, 63, 70.
Zodids, 118, 119.
Zoophytes, 113, 119.
Zostera marina, 12.
Zygodactyla, 128.

Z. groenlandica, 116, 128.

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