guideC o.

TO THE

COEAL GALLBEY

I

(PROTOZOA, PORIFERA OR SPONGES, HYDROZOA,

AND ANTHOZOA),

IM

THE DEPAETMENT OF ZOOLOGY

BRITISH MUSEUM (NATURAL HISTORY),

CROMWELL ROAD, LONDON, S.W.

WITH NUMEROUS ILLUSTRATIONS.

SECOND EDITION.

oil LONDON:

CTuo^'^INTED BY ORDER OF THE TRUSTEES OF

]_J[}'l THE BRITISH MUSEUM.

1907.

GUI I) E

TO THi;

COEAL GALLEIJY

(PROTOZOA, PORIFERA OR SPONGES, IIVDROZOA,

AND ANTIIOZOA).

IN

THE DEPAETMENT OE ZOOLOGY,

BEITISH MUSEUM (NATURAL HIST(.)RY).

CROMWELT. ROAD, LONDON, S.W.

WITH NUMEROUS ILLUSTRATIONS.

SECOND EDITION.

LONDON :

PRINTED BY ORDER OF THE TRUSTEES OF THE

BRITISH ^rUSEUM.

Ii)07.
(.1// rifjhts ri'iiervcd.)

LONDON :

PRINTED KV WILLIAM CLOWES AND SONS, LIMITED,

DUKE STREET. STAMFORD STREET S.E., AND GREAT WINDMILL STREET, W.

L

11

I' i: i:i- AcK.

Till'] Coral Gallerv, the contents of whieli are Itrielly deHeribcil in
the following pa;4es, is a lung narrow curridDr situat^jd between the
IJird (Jalleryand the series of galleries on the north side of the
l)uiidiug, being interrupted by three cross-passages between the
galleries referred to. The collectiuns exhibited in this gall'-ry
include not only the objects commonly recognised as Corals, but also
other lower types of animal life scientifically known as Hydrozoa,
Forifera and Protozoa, which include jelly-fish and their alli<s,
sponges, and microscopic organisms such as Foraminifcra ami
liadiolaria, which in the remote past have played an important
part ill the formation of the chalk and lime-tune rocks of the
earth's crust. In giving an account of such objects as these it is
(liHicult to avoid the use of many scientific and technical terms, but
au endeavom' has been made to make the text as comprehensible iks
possible to the general pul)lic. Much care has been bestowed upon
the si'lcction and preparation of the numerous illustrations, many
of which are entirely new. The part of the (iuide referring
to Protozoa, Porifera and Hydrozoa has been prepared by Mr. R.
Kirkpatrick and the description of the Anthozoa l)y Mr. F. J. Bell.
In conclusion, thanks are due to Dr. Gust-.iv Fischer of Jena, to
Messrs. F. Warae & Co., Messrs. Cassell & Co., :Messrs. Macmillan
& Co., Messrs. A. and C. Black, Messrs. J. and A. Churchill, the
Royal and the Royal ^licroscopical Societies for kindly allowing the
use of illustrations in various works published by them.

E. li.VY L.VNKKSTKU.

PKEFACE TO THE SbX'OND KDlTloN.

Ax additional eight pages on the important subject of Sporozoa

and certain allied organisms (including the ]>arasites which cause

.^[daria and SL-epiiig Sickn.'S-;) have been inserted between paire-s

1 1 and !."», anl have been numl)er.'d 1 kv -it ; also eight additional

figures designated Kia— ii have been added.

K. Kav liANKt:sri;it.

TABr.E OF CONTEXTS.

Pbotozoa or Simplest Aximals
Introduction

Gymnomyxa or Rhizopoda
Foraminifera or Reticularia
Corticata or Infusoria

PORIFERA (Sponges)
Introduction
Classification

Calcarea (Calcareous sponges)
Silicea (Siliceous sponges)
Demospongire or common sponges

Hydrozoa

Introduction

Hydroida (Hydroid zoophytes)
Hydrocoralliufe (Coral-like Hydrozoa)
Medusae (Jelly-fish)

Anthozoa (Sea-Anemones, Stony Cor

als, Bark Corals, etc

1-19
1

3

I

14

20-37
20
23
25
24
2'J

3S-C6
38
40
47
54

G7-71

GUIDE TO THE COllAL i.ALLKIlV.

PROTOZOA OK SLMl'LEST ANIMALS.

Introduction.

The majority of the Protozoa are extremely small objeets, bein^ High Wall
in many cases invisible or barely visible to the naked eye. Conse- p'*'^;' , ,
quently, excepting in certain instances, diagrams and models are Caiiery.
exhibited in place of specimens.^

The Protozoa are essentially composed of one " cell." The word
" cell " was originally used to describe a vegetable cell or vesicle with
its walls and fluid contents, just as we speak of a bottle of wine ;
but now the term is used for the minute corpuscles of protophism
or living substance which build up animal and vegetable structures.

The Protozoa stand in contrast with all the rest of the Animal
Kingdom or Metazoa, the latter being composed of many cells of
different kinds united into a commonwealth organised on the
principle of division of labour. In the figure of Hydra (p. ;5'.»), for
instance, we see a sac composed of two layers of " cells,"' those of
the iimer layer being concerned in the digestion of food, those of
the outer having protective and sensory fimctions ; here each cell is
subordinate to the community of cells and cannot live independently.
Many Protozoa form colonies, but the individual cells resemble each
other, and each cell is independent of the others.

By way of introduction to the subject, a brief description of a
Protozoon is given below.

Ama-ha 2)roteus, or the i'roteus Animalcule (Fig. 1), resembles
a tiny blob of whitish jelly about -^-^ of an inch in diameter ; it is
commonly found at the bottoni of ponds on the ooze, where it cri't'ps
about in search of food.

The Amffba, observed under the microscope, usually seems
globular and motionless at first, but presently beads appear on the
sm-face, some of which enlarge and How out in the form of tingcr-likf

' The diagrams and models exhibited in the Case arc roforri'd to in tho
text as "Plate and Model," with their appropriate numlwr.

GUIDE TO THE COKAL GALLERY.

High Wall

Case

E. end of

Gallery.

lobes. The lobes are termed " psendopodia " {psendos, false or
apparent ; 2^oiis, foot), because they enable the animal to move
about. " In the continual extension and branching of one or more
of the chief pseudopods," writes Professor Leidy, " the Anireba
progresses more or less rapidly, the body appearing incessantly
to exhaust itself in the continual growth and elongation of the
pseudopods and in the production of new ones, while it is as

Fig. 1.

Amceha proteus, the Proteus Animalcule. Figure on left, small specimen, mag-
nified 250 diameters. Figure on riglit X 200. n. nucleus ; c v, contractile
vacuole ; /, foreign bodies ; p, pseudopods. Arrows indicate direction of
streaming of pseudopods and of motion of the animal. (After Leidy.)

incessantly replenished by the contraction and melting away of
pre-existing pseudopods." The little creature is continually chang-
ing its shape, and hence Rosel, who discovered it in 1755, called it
" the little Proteus," after the monster of the fable.

When the Amoeba comes in contact with a Diatom, Desmid, or
other object suitable for food, it envelops and ingests it, and, in
due time, casts out the indigestible debris.

PROTOZOA OR SIMPLKST ANIMALS. 3

Food may ])e taken in and thu remains ejected at any ixjiut o; . all

the body, but sometimes only over more or less definite areas. Tb<-
body of the animal is usually crowded with food-balls, shells of Gallery.
Diatoms, cells of green algae, «&c.

The protoplasm of the body, with the exception of a thin, clear,
outer layer, is granular ; at one part (Fig. 1) is seen a discoid, denser
portion of protoplasm, known as the " nucleus." There is also
present in the interior of the body a clear spherical vesicle— tbe
" contractile vacuole " — which slowly expands and rather suddenly
collapses and disappears, reappearing at the same spot and goiuir
through the same cycle. The contractile vacuole is probably an
organ for the excretion of waste products. The animal reproduces
itself by dividing into two, this process being preceded by division of
the nucleus, each half of the Amieba becoming a di.stinct individual.

Classification.

The Protozoa are divided into two great sections — the (iYMNO-
MYXA or Rhizopoda, and the Corticata or Infusoria.

In the first section, the protoplasm of the cell is homogeneous
throughout, but in the second the superficial layer is firmer than
the more fluid interior portion.

The Gymnomyxa, in their adult phase, move about and obtain
their prey by means of pseudopods. The Corticata are provided
with flagella or cilia. A classification of the Protozoa (after Prof.
Lankester, Emyc. Britannica) is given in the " Explanation of
Plates " in the Case.

GYMXO:^rYXA (RHIZOPODA).

For simplification, the Gymnomyxa are here divided into four
groups : —

I. LoBOSA, with lobose pseudopods.

II. Hei.iozoa, with fine radiating pseudopods.

III. FoRAMiNiFERA, in which main trunks of pseudopods branch
out into a fine network, and with a shell usually composed of carbonai.
of lime.

IV. Radiolaria, with a "central capsule," with fine nuliating
pseudopods, and usually with a shell of silex or horny acantliin.

GUIDE TO THE COEAL GALLERY.

High WaU

Case

E. end of

Gallery.

LOBOSA.

The LoBOSA, or Gymnomyxa with lobose pseudopods, may be
without shells, as Amala (see Plate III. and Model 1 in the Case),
or they may be enclosed in a shell, as, for example, Diffliigia
piriformis (Model 2) and Difflugia acuminata (Plate III. in Case),
in both of which the shell is composed of cemented sand-grains.
The shelled forms creep about with the shell uppermost and with

Fig. 2.

Actinophrys sol, the Common Sun-Animalcule. The large globule
projecting from the surface is a contractile vacuole. Magnified
500 diameters. (After Leidy.)

the pseudopods emerging from the aperture below. The Lobosa
live, for the most part, in fresh water, damp moss, etc.

The Mycetozoa, or Fungus Axkl^ls, which may be con-
veniently referred to here, are, by some naturalists, regarded as
vegetable organisms. In dealing with the lowest organisms, it is
often difficult to determine definitely their true position in the
kingdom of life, whether they are to be regarded as members of the

PRdTOZOA OR STMI'LEST ANIMAI.S.

iiuiiiial or vegetable kingdom, or as being in an intermediate position. Hiqh Wall
In some phases of their life-liistory, .Mycctozoa exhibit charactei-

attribiitcd in vegetabU; organisms; in othi-r phases, a»ain, they (j^ijerv.

Vie. :{.

if

Clathrulina eleQum, thn Latticed Sun-AiiimalouU-.
Magnified ;i"if1 diamotcra.

resemble und(»ubted animal organisms. One of the best known
forms is Fnliyo scjilira, which creeps over the snrface of tan-pMs.
Th(; creeping " plasmndinm "" develops masses of cysts kn<.\vn as

6

GUIDE TO THE CORAL GALLERY.

High WaU

Case

E. end of

Gallery.

" flowers of tan." The cysts rupture and liberate AmocM-like
spores (flagellulffi), which fuse together to form a plasmodium.

Didymivm, one of the Mycetozoa, is figured in Plate II. in the
Case.

TIeliozoa or Sun ANr:\iALCULES.

The Sun Animalcules are more or less spherical in form and pro-
vided with fine ray-like pseudopods. They mostly inhabit fresh water
Actinoplirys f<ol, the Common Sun Animalcule (Fig. 2), lives

Fig. 4.1

Miliolina tenera, one of the Imperforate Foraminifera. Young
living animal with expanded pseudopods. A nucleus is seen
in the innermost chamber. Magnified. (After Max Schultze.)

amongst weeds in ponds. " It commonly appears as a globular,
hyaline, foamy, or vesicular body, bristling with delicate rays, land
suspended almost stationary in the water" (Leidy). The total
diameter is about oV of an inch. The body generally contains, in
addition to the central nucleus and the contractile vacuole, nimierous
vacuoles and food-balls : the contractile vacuole is usually seen
emerging from a point on the surface, bursting, and reappearing at
the same spot (Model 3). Actinopkri/s swims by means of its
flexible pseudopods, and when one of these touches some organism,
the latter is drawn towards the body and engulfed. Well might

From " Encyclopfedia*Britannica,"

PROTOZOA OR SIMPLKST ANIMAI-S,

.Joblot, who, in IT'it. tirst discovered it pirouetLing ubuiu in an Fli^rh Wall

infusion of celery, speuk of it iis " ihr most extraordinary fish on

could imagine." A continual streaming of the protoiilasin rendered Gailcry.

visible by the granules in its substance is coutinually proceeding up

and down the pseudopods. The little organism reprorhiccs itst-lf by

dividing into two (Model 1).

Actinosp/uerinm ekhoniii (see I*late V. in ihe Case) luis a spherical
body with a well-defined outer zone of large vacuoles ; this fornj,
which is also abundant in ponds, somewhat resembles a giant Sun
Animalcule, being al)out five times the size of Ai:tiii(ij)/iri/s.

Ii/uij)/ii/iop/ir//s ('/('//an.s may be either solitary (Model .">), nr may
form colonies in which several of the spheres are joined l)y bands
(Model (J) ; numerous slender curved spicules of silex abound in
the surface layer of the body and pseudopods.

Clathridina eiegans (Fig. 3), which lives in ponds and ditches,
may be compared to a Common Sun Animalcule enclosed in a
latticed sphere of silex supported on a slender stalk ; the diameter
of the shell is about ^^^ inch, and the length of the stalk about
Y^ inch. See Model 7 in the Case.

FORAMINIFERA OR PvETICULARIA.

The majority of the Foraminifera form a shell of carbonate of
lime ; in some, the shell is composed of cemented sand, mud, or
sponge spicules, and, in a few species, of inembraiic or silex. The
series of Foraminifera mounted on slides is arranged in ten families
according to Mr. H. B. Brady's classification, an enlarged figure
being placed below each slide. The classified series is ].receded by
an introductory account of the group. The small plaster models on
steps and on the floor-shelf represent selected types, both living
and fossil.

When the skeletons of Foraminifera were first discovered, they
were supposed to be the shells of tiny Cephalopods <.r other :Mo11uscs.
Great was the sensation in the scientific world when, in lf<;',.".,
Dujardin found, from observation of the living animals, that the
builders of these complicated shells consisted simply of apparently
structtn-eless protoplasm, which extnuled root-like trunks of branch-
ing and anastomosing tlireads whereby the creatures crept along
(Figs. I, ")). Accordingly he removed these organisms from the
MoHusca and placed them in a new grou].. RhixA.j.oda "•/"-■'. ''-■' :

poui<, foot).

Foraminiferal shells either have only one or a few main aiKjrtuivs

Fig. 5.

Polystomella, one of the Peiforate Foraminifera, showing trunks of pseudopods
emerging from the shell. Magnified 200 iliameters. (After Max Schultze.')

Fig. 6.

A section of Nummulitic Limestone from a Himalayan Peak 19,000 feet above

sea-level. Magnified 40 diameters.
In the upper left corner of the plate are vertical sections (willow leaf pattern),
and near the upper right corner a section, in horizontal plane, of Nummitlites.
Distributed over tlie field are numerous sections of MilioUna, Botalia, Textu-

laria, S^c.

To face p. 9,

PROTOZOA OR SIMPLEST ANIMALS.

9

(Imperforata, Fig-. I), or liiVf, in additiou to the main aperture, the High Wall
wall of the shell perforated by uumeroius pores (Perforata, Fi}^. .'i). ^j^^=
Calcareous imperforate shells (see Family II.) have an opatjue white Gallery!*
poivellanous appearance, and perforate shells, in their early 8tii«<e.s,
a vitreous appearance (Families V. to X.). The shell may consist of
one chamber {Laijena, Family VII.), or of many, arranjred in linear,
spiral, or concentric series, or on each side of a middle line.

In Globigerina, Ro/a/ia, &c. (Family Vlll. and IX.), all the
chambers of the " rotaliform " spiral are visible from above, Init

Fig. 7.

Shells of Glohigerina, showing lower ami upper surface. Mugiiilied.

only the last coil from below. In XinnniNlifon (Family X. and
Introductory series) the last coil of the spiral wholly encloses all the
preceding coils.

Although many of the specimens in the Case are very small, yet,
with the aid of the diagrams, the shape can frequently be made out ;
in some species the shells attain to relatively innnense proportions,
as Gijdoclypeus mrppnlerii (Family X.). from r«>rneo, with a thin
discoid shell over two inches in diameter.

The Foramiuifera have played an imporlani pan in fi>rming

10 GUIDE TO THE CORAL GALLERY.

the rocks (chalks and limestones) of the earth's crust, and at the
present time are covering millions of square miles of the ocean floor
with a pinkish-white mud or ooze, formed chiefly of their skeletons.
The shells of Globigerina hidloUles (Fig. 7 ; and specimens and figures
in Introductory series), a species which lives at the surface of the
ocean, form a large proportion of the ooze, which is hence termed
" Globigerina Ooze." The piece of dark-coloured Tertiary Nummu-
litic limestone (Fig. 6) exhibited in the Case, formed part of the
debris from the summit of a Himalayan peak 19,O0U feet above the
sea-level. The occurrence of this ancient sea-floor in its present
position affords clear proof of the elevation of the peak within —
geologically speaking — comparatively recent Limes.

The large plaster models of Biloculina illustrate " dimorphism,"
a phenomenon now found to be of frequent occurrence in Foramini-
fera, and attributed to alternation of generations.

One of the vertical sections shows a large central chamber
(megalospheric form), and the other shows numerous small ones
(microspheric form). Parallel series of fossil Niunmulites (see
Introductory series and Family X.) are often found together in a
stratum, disks with small central chambers occurring along with
usually smaller disks with large central chambers ; formerly the two
kinds were regarded as different species, but are now considered to be
different forms of one and the same species.

Radiolaria.

The characteristic feature of the Radiolaria is the presence of a
membranous " central capsule " dividing the body into two zones, an
intra-capsular zone including the nucleus, and an extra-capsular
whence the pseudopods radiate. The vast majority form a skeleton
of silex or of acanthin, a horny organic material ; a few species
are without a skeleton.

The Radiolaria live in the warmer waters of the ocean, mostly at
or near the surface, but some species exist only in the deeper zones.
Over vast areas in the tropical Pacific and Indian Oceans, and at
depths of about 3,000 fathoms, the ocean floor is composed of an
ooze chiefly made up of the skeletons of Radiolaria, and hence
termed Radiolarian Ooze. Certain rocks, as, for instance, Barbados
Earth, are largely or almost entirely composed of Radiolarian
skeletons.

"When floating alive at the surface, Radiolaria are often richly

PROTOZOA (tU SIMI'LKST AN'IM.V[,s.

II

coloured with crimson, blue and yellow tints, and have been w.
termed "gems of the ocean." Their skeletons a&sume an eii "
variety of beautiful and curious shapes, such ;i.s spiny lau.
spheres, rings, ])eehives, &c. The Radiujaria, (.f whidi alx)Ut
1,<»00 species iiavc l)eeu described, arc j.riinarily classified accordiii«^
to the structure of the central capsule, the shajM- of the skelet<in
tending to conform, more (»r less, lo the shai)e of th.- latter.
Professor llaeckel divides the group into four Orders : -

Fk;. 8.'

IlaJiommd iryvillei. Magnifi('(l 200 (liiiiiictca-s. (After Wyvillc TIioiikmhi.)

I. SpUMPiLiiARiA (Fig. 8), and see Plate VI I. and .Models ;i-1l>
in the Case, with spherical central capsule uniformly )H'rfcirate<l by
pores. Here the skeleton is typically formed of a latticed sphere or
of several concentric latticed spheres united by radial beams wliicii
do not penetrate the central capsule, and with radiate spines.

o(

' From "The Voyage of the (7«j//fH(/('c— Atlantir.

12

GUIDE TO THE COEAL GALLERY.

High Wall

Case

E. end of

Gallery.

Spongosphnra (Model ] 2) lias three spheres, the outermost consisbiug
of a spongy reticulum ; the fine smooth spines in this model represent
pseudopods, but the pseudopod rays are beaded in the other models.
Spongosplupra streptacantha, which is common on the surface of
warm-temperate and tropical seas all over the world, is about
^V of •T'O inch in diameter.

IT. ACANTHAETA (Fig. !), and Model 13), with spherical porous

Fig. 9.'

Xiphacanfha murrayana. Magnified 100 diameters. Skeleton only.
'After AVyvillu Thomson.)

central capsule, with skeleton of "acanthin," constructed of 20
radiate spines proceeding from the centre, and always arranged in
fours according to a definite law known as " Miiller's Law," The
idea of a terrestrial globe with its parallels helps one to realize the
plan ; thus Haeckel calls the five fours equatorial, tropical and

> From "The Voyage of the Challenger.— AtlaLXitic."

PROTOZOA <)U SIMPLEST ANIMALS.

13

polar. The radiate spiues give off hurizontal or tangential spinrs orHish Wall
plates, which may remain separate (Fig. 0) or may fuse to form a J;]''^-
latticed sphere (see Model 13 of Dorataspis diodon in the C51.se). GaUerv*^

III. Nassellarla.. The central capsule is conical, and perforatwl

Fio. 1(1.'

\\v^>\\^0

Euci/rtidium cranioidis. Entire animal as seen in tlie living
t'ondition. Mai^nified 1.50 diameters. (After Hneckel.)

only l)y a large opening in the basal rciiion. Eunirtidium (Fig. 1 < 0 and
iJidyupodium, see Models 14, in in Case, arc beehive-shaped with throe
segments. The yellow balls situated on the pink central capsule repre-
sent a symbiotic Alga, commonly found associated with Kadiolaria.

From " Encyclopnedift Britniinica."

14 GUIDE TO THE CORAL GALLERY.

High Wall EucecrijplwJus sdiultzei has only two segments, the lower being

£^®® , , expanded out, and the central capsule is lobed ; see Model IG in Case.
Gallery. IV. Phaeodaria (Models 17, 18), with a double-walled central

capsule with a few large orifices, and surrounded by dark brown
pigment. The skeleton of Auhsphcera (Model 17) is formed entirely
of tubes of silex, which join to form a spherical lattice with triangular
meshes, a tube with verticils of spines radiating from each node.
This species, which lives at the surface in the Mediterranean, has a
large shell ^^ of an inch in diameter.

Aulacantha (Model 18) has a skeleton formed of hollow siliceous
tubes of two kinds, viz., radiating spines and loose needles arranged
tangentially on the surface.

CORTICATA OR INFUSORIA.

If any animal or vegetable substance be allowed to remain in a
vessel of clear water exposed to the air, in a short time tiny specks
will be seen swimming about. The organisms appearing in these
infusions were termed Infusoria or Infusions Animalcules. The
organic matter has simply served as nutriment to the germs of
these Animalcules previously existing in the water or in the air.
Infusoria abound in fresh and stagnant water and also in the sea.

The organisms grouped under this name differ from the Gymno-
myxa, in having, in their adult phase, a dense cortical body-layer and
often flagella or cilia in place of pseudopods. A cilium is a hair-like
organ which can only bend and straighten itself, and which only
acts in unison with other cilia. A flagellum acts independently, and
with a lashing to and fro movement.

The Corticata may be roughly divided into four groups : Sporo-
zoa, Flagellata, Ciliata, and Acinetaria.

Sporozoa.

The Sporozoa are parasitic Protozoa which live in the tissue-cells
and fluids of other animals. The study of these organisms has of late
years acquired an immense importance on account of the wide-spread
and dangerous maladies to which some of them give rise in man,
domestic animals, fishes, &c. For instance— to mention a few of the
more important diseases — the various kinds of malaria in man, Texas
fever in cattle, coccidiosis in rabbits and other animals, " psorosperm "
disease (myxosporidiosis) in fishes, silkworm disease, and sarcospori-
diosis in cattle, are all due to the presence of Sporozoa in the blood

I

PROTO/OA OU SlMl'LKS'I' ANIMALS.

14.

Jl

or tissues. Mention m:iy conveniently be made here, ulso, of Sleeping
Sickness and Tsetse disease, caused by the presence in the bl<j<Ml.
respectively of man and of domestic animals, of a parasite {Try-
panosoma) belongini? to the Flagellata antl allied t<t the Sporozoa.

General Chauactehs of the Oiioui'.
The Sporozoa, from their i)arasitic habit of Fig. ioa.

passively absorbing the juices of their Ixjst, lack JUSt^

organs for capturing and digesting food. Usually
they are of more or less deiinite form, and with
the cell body bounded by a cuticle. Generally
they are stationary, though some move by means
of pseudopods (like Amocbixi), and some have
flagella during a phase of their life cycle. The
most important cliaracter, and the one to which
the group owes its name, is that of forming
spores or germs, which arc commonly enclosed
each in a tough envelope or cyst (Fig. 10b), and
often all the spores formed from one parent cell
are enclosed in a common cyst. Tiie conditions
necessary for the existence of these organisms are
so nicely adjusted that each species of parasite is
usually confined to the same or an allied species
of host, and to the same tissues of that host.

The Sporozoa may be grouped under the fol-
lowing headings : — (1) Gregarines, (2) Coccidia,
(8) Myxosporidia and Sarcosporidia, and (4) Para-
sites of the blood.

(1) Gregarines. These organisms are of very
common occurrence in the intestine and body
cavity of invertebrate animals.

Porospora gigantea (Fig. Ioa), from the
intestine of the lobster, is an unusally large
species. Specimens, which may be nearly an inch
in length, look like small worms, yet in spit*.' of
such huge dimensions they consist of only a
single cell with a nucleus. The cell 1)ody in
this and some other species is divided into two
segments, the upper one Ijeing small and often (After "an
modified so as to become an efficient fixing organ. from Lm;

MonocijHtis Of/ilis is very commonly found \\ ithin the spenu siws
of earth worms. The little elongated oval Gregarine lives in it.s

II

/J

Porosjwra fiitianUa,

X 150.'

from intostino of

Lobster.

14b

GUIDE TO THE CORAL GALLERY.

earliest stage in the interior of a sperm morula (or mother cell which
gives rise to the spermatozoa). The parasite grows at the expense of the
cell and becomes free of it and actively motile. This is the nutritive or
trophic phase, and the organism is termed a trophozoite. The fully-
grown trophozoite becomes associated with another like itself, and
the two form round themselves a common cyst ; the nuclei of each
break up, each nuclear particle surrounding itself with a little of the
protoplasm of the mother cell, and becoming a sporoblast or gamete.
True conjugation now takes place, each gamete of one motlier cell

Fig. 10b.

Ripe cyst of Monocystis agilis, X 750, showing the spores
(pseudonavicellse) within the cyst. After Lankester.

coupling with a gamete of the other, thus forming a " zygote." The
zygotes become oval and secrete a tough membrane or sporocyst,
thus constituting true spores. Lastly, the protoplasm of the spore
divides up into eight sporozoites. Fig. 10b shows a cyst containing
oval spores, formerly termed " pseudonavicellas " because they
resemble in shape the Diatom NaviciiUa. The spores pass out of the
body and are casually eaten by another earthworm ; then the spore
cyst ruptures and the sporozoites escape and actively burrow through

I

rnoTozoA <»K siMi'i.Ksr animals.

n.

the intestine till they reach the sperm s;ics ; uarh sporozoiu- attiu-kn
a sperm morula and throws into a trophozoite, thus compK-tinj; the- cyije.

(2) CocoiniA. The Coceidia most commonly attack epithelial
cells, such as those lining the intestine or livcr cells.

The parasite (Jinridium srlnih<-nii, wliir-h is found in the
intestine of the centipede Llthobins forjiratiis, «:ro\vs inside the
Fig. 10c.

%.

Fic. 10e.»

v^

'??

i>nd

r\

,.--ect

y

Cliloroi)uj.i:nm ?c»/<7i</!, x 525,
parasitic ou Dog-tish and Ray.
EcL, ectoplasm; ]>s., pseudo-
podia ; end., cndoplasm ; r/,
yellow globules ; sp., spores
with polar capsules. After
Theloban. (From Miuchin's
Sporzoa, Lanicstcr's Treatise
ou Zoology.)

Section of rabbit's liver infected with
Coccidium ouiformc. After Balbiani.
(From Minchin's Sporozoa, Lan-
kester's Treatise on Zoology.)

infected cell, and at its expense, into an oval or spherical hody.
A\'li(ii full growth is reached, the parasiti; undergoes division
iiiLo a number of small cells (inerozoites), each of which hecomes
free and attacks another c|)ithelial cell, attains maturity, and
itself undergoes division, so that at last all the <'pith»limn may
be destroyed; but a time comes when souu' of ilu' nuTozoiics
become distinct male and female cells, the male breaking up into
male " gametes," each with two IJagella, the female remaining as a

* For Fig. lUiJ sue p. 14 d. II ;{

14d

GUIDE TO THE CORAL GALLERY.

single large cell. When the latter is fertilised by one of the male
gametes, the resulting zygote forms round itself a cyst, while the
contents break up into sporoblasts, each of which forms a double
envelope and becomes a true spore. Lastly, the spores divide, each
into two sporozoites.

Fig. 10c. shows a section of the liver of a rabbit suffering from
Coccidiosis, due to the presence of Goccidium oviforme.

Fig. IOd, a — e shows a zygote dividing up into spores, / being
a spore with two sporozoites.

(3) Myxosporidia and Sarcosporidia. Myxosporidia are
mostly parasitic in fishes, in which they are commonly situated
'beneath the epidermis of the gills and fins, and in the wall of the
bladder. The body of the parasite is an Amoeba-like cell (Fig. IOe),

Pig. IOd.

Spore formation \uCoccidmm oviforme from liver of rabbit. Highly magnified ;
a, encysted individual (zygote) ; h, zygote contracting to a sphere ; c, d, c,
division into spores ; /, single spore, more highly magnified. After
Balbiani. (From Minchin's Sporozoa, Lankester's Treatise on Zoology.)

which may multiply by dividing into two, or by forming bnds ;
quite early in life spores are formed in the cell body. The spores
contain peculiar pear-shaped bodies, each of which contains a coiled
thread. When another animal swallows the spores, the stimulus of
the digestive juices causes the extension of the coiled filaments, which
thereupon attach the spore to the wall of the gut.

The Sarcosporidia are found }>arasitic in the striped muscle fibres
of cattle and pigs, in which animals nniltiplication and growth of the
parasite often sets up abscesses in the tissues.

C4) Parasites of the Blood.

See Models and Diagrams in the Central Hall.

One of the most important discoveries of recent times, and one
certain to have extremely beneficial consequences,* has been that of

* On the occasion of the delivery of the inaugural address of Prof. E. A.
Minchin, Professor of Protozoology, Sir Lauder Brunton pointed out that
the darkness of darkest Africa was probably in no small measure due to the
prevalence of biting flies, ticks, &c,, infected with Protozoan parasites, Not

PROTOi^OA on SIMlMJvST ANIMALS. 14e

tlu! ciiiise of Malaria or A^ne. For (Mjuntless iroiierations man has
sulfered from this mysterious malady, and inimmeraljlc theories, sucli
as its bein.if due to the effects of the bad air— hence the name
" ^Falaria "— of marshes and soils, rai)id variations of tem[KTature,
heat of the sun, &c., &c., have been broui^ht forward to account for it.

It is only within the last, quarter of a century that the reiil cauiic
has become delinitely known. In \Hs2 fiiiveran, a French docU^)r
at Algiers, found the blood of patients suffering frum malaria in-
fested with an organism to which he gave the name Oscillnrin
malarm, under the impression that it was a vegetable ; and, further,
he showed that the symptoms of the patient resulted from the
])rcsence of this organism in the blood. Later, the parasite was
found to be a Sporozoon, and was named Lnverania malar i^n. Tlu,-
next great discovery was that of the means whereby human beings
became infected. The labours of Ross, Grrassi, and others showed
that the agency whereby the malarial parasite was inoculated intotlie
blood was that of the stab of the blood-sucking mosquito. Anopheles.
It was found that the mosquito was not a mere carrier, Init a true
intermediate host, in whose body the malarial germs underwent the
sexual phase in their life history. A Jjrief account of the life cycle
of one of these blood parasites will now be given.

Pernicious malaria is caused by the Ilajmosporidian Lnverania
malarm. An Anopheles infected with the germs (exotospores) of
Laverania stabs the skin of a human being with its piercing and
stictorial proboscis. The mosquito [)ours into the wound a tiny drop
of its saliva, which is crowded with the Laveraaia germs.

Each minute spindle-shaped exotospore (Fig. IOf, a) attacks and
penetrates a red blood cell, and becomes an amrebula, which grows at
the expense of the blood cell (Fig. IOf, l),c) ; when mature the amcebula
divides up into a rosette-like group of " enhiemospores " (Fig. lOF, d).

The blood cell breaks down and the liberated enluemospores
(Fig. 1()F, e) proceed to attack other blood cells within which they
grow into amcebula), which again divide up into rosettes. In tertian
ague, due to Plasmodium viva.r, this cycle takes forty-eight iioui-s,
and the onset of the fever every third day coincides with the
liberation of enhicmospores and the attacking of fresh blood cells ;
in quartan ague, due to Plttsmadimnmaliiriic, the cycle takes .seventy-
two hours.

only has Man's life and health been seriously affeited, but intereommuuioa-
tioii prevented by the extermination of domostic uniiniils. AlreiKly. tliiiiik>
to the labours of men of science, localilies formerly postiforous liiivc boromo
salubrious.

t'iG. IOf.

*- '

II

Life Histoky of the Malaria Parasite.
exotospore, or malarial germ, as introduced into the blood by the mosquito ; b, exoto-
spore after entry into blood corpuscle ; c, growth of exotospore into an amcebula ;
d, division of ama-bula to form enhsemospores ; e, liberated enhfemospores ; /, gi-owth
of enhsemospore into a crescent at expense of corpuscle ; g, male, and h, female
crescent ; i, male cell with projections, which lengthen, and are eventually set free
as spermatozoa ; j, fertilisation of ovum by spermatozoon ; Ji, fertilised egg as the
active motile vermicule ; I, enlarged vermicule, after boring through the stomach
wall of the mosquito, forming the sphere ; m, segment of sphere at maximum stage
of development, containing countless needle-shaped spores, which, when it bursts,
escape as exotospores into the organs of the mosquito's body and pass through the
salivary glands into the proboscis, and so infect a man bitten or pricked by the
mosquito. (The figures are taJien from enlarged models exhibited in a case in the
Central Hall of the IMuseum.1

PROTOZOA OR SIMPLEST ANIMALS. 14r,

Tho invudiui; euciuy is attacked and partly held in check hy the
white blood cells, which devour and desiroy many of the enhitnio-
spores before they become ensconced inside the helpless red blood cells.

If the malaria parasite had to depend on the aljove asexual mode
of propagation by simple division, it would soon become extinct ;
the host would die, and the ])arasite also. For the mosquito wholly
digests ama'buhc, rosettes, and enlucmospores along with its meal of
blood, and accordingly is unable to convey them alive to another
host having a fresh supply of blood cells.

After a certain number of generations of asexual ilivision,
however, the full-grown amrrbuliE, instead of dividing up into
euhasmospores, become sausage-like crescents (Fig. I of,/), some of the
crescents being male (Fig. lOF, //) and others female (Fig. lOF, //),
the sexes being distinguished by the mode of distribution of the
dark granules (see figures). No further changes take place in the
human host, but if an Anopheles now sucks the blood, and takes in
the malaria germs, the male and female crescents and spheres are not
digested, but become spherical and develoj) as follows : the male
spheres suddenly push out projections which lengthen (Fig. IOf, /')
and very rapidly become free as wriggling spermatozoa ; the female
cell attracts a spermatozoon, probably by chemical allni-ement
(Fig. 10F,y) ; the two elements fuse and the resulting fertilised ^y:,^^
or zygote becomes an actively motile vermicular cell (Fig. KiF, k),
which burrows through the stomacli wall of the mosquito, where it
forms a sphere (Fig. IOf, /). The sphere nowgrow'sto a considerable
size (Fig. IOg, showing many spheres on the wall of the stomach), and
its contents break up into sporoblasts, which again give rise to
countless spindle-shaped exotospores (Fig. Kif, m). The sphere bui-sts
and the exotospores are conveyed into the tissues and organs of the
mosquito, many of them coming to rest in the salivary glands,
whence they are finally inoculated into a human being when the
mosquito stabs the skin ; and we now arrive at the point whence we
started.

Tlie terrible Bleeping Sickness of man, and theXagana or Tsetse
disease of domestic animals are both due to the presence in the blood
of different species of a minute corkscrew-like flagellate organism
Trypanosoma — which though mentioned here must Itechussed with the
group Flaoellata. The body of the Tri/pmiosoiud (Fig. Inn) is
provided with a lin-like extension, and with a flagelhim. As in the
case of malaria, there is an intermediate iiost, the blood-sucking
Tsetse fly, which inocidates the 7\-i//i(iiiosoiti(i into the blood of its

14h

GUIDE TO THE CORAL GALLERY.

victim. The life history of one of these parasites has been fully
worked out by Schaudinn in the case of the Trypanosome (^Trypano-
niorpha nodufe) of the Stone Owl, the other host being the Gnat
(Ciilex pipiens). The Stone Owl is tolerant of the parasite's existence,
and suffers no harm from its presence. The G-nat is a true host, the
parasite undergoing its sexual development in the intestinal tract
(see the case and illustrations in the Central Hall).

The Sleeping Sickness prevalent in Tropical Africa is set up by
the stab of a Tsetse fly {Glossina paJpaUs) infected with Trypanosoma
yambiense, the fly itself having become infected by suckiug the blood
of a human victim of Sleeping Sickness, or possibly that of some
native tribes who have become tolerant of the existence of the parasite.

Fig. IOg.

Fig. IOh.

Stomach of mosquito with cysts of
malarial parasite, X 40. Ocs., ceso-
phagus; si., stomach ; c?/., cysts; 7nt.,
malpighian tubules ; int., iutestine.
After Ross. (From Minchin's

Sporozoa, Lankester's Treatise on
Zoology.)

B.

Trypanosoma gambiense, very
highly magnified from human
blood. (A, after Bruce and
Nabarro ; B, after Castellani.
From H. M. Woodcock,
Quart. Journ, Mic. Sci.)

At first the Trypanosome (Fig. IOh) multiplies in the blood, but, later,
gets into the cerebro-spinal fluid, where its presence gives rise to the
peculiar nervous symptoms of drowsiness ending in coma and death.

The Tsetse disease of domesticated animals is caused by the
blood parasite Trypanosoma hrucei, which is inoculated by the stab
of the Tsetse fly {Olossina morsitans, and other species). The
Tsetse fly itself becomes infected by sucking the blood of wild
Antelope or Buffalo, which are tolerant of the existence of the
Trypansome in their blood ; but imported cattle, as in the case of .
human beings immigrant in a new region, are not tolerant, and die
from the effects of the rapid multiplication of the Trypanosome in
their blood. The Tsetse disease is prevalent in S.E. and S. Africa.

rnoTozoA (ti: simi'i.ksi' animals.

l.'j

ri..\(;i;iJ,ATA.

I'lii' Fi-.\(;i;j.LATA are CorLiciitii in which Uit- (.vll-lju,ly is j-rovick-a High Wall
with one or a few Hagelhi. 'I'he cell may Ijc solitary (Viir. II a), ..r ^y*^'
may lie joined with others to form colonies (Fij^s. 111!, rj^ ' Oaiu'rv*''

Fig. II.

Flagelliita. a. Cerconionus crdssicuudd, a oue-cfllctl Fliijjfllalo ( x -Idd).
li. Govium 2)ector(ile (X 825). c. Volvox glohator witii daiiglitcr and irraml-
ilaiij^hter culoiiics ( X 55). (Alter Carter.) D. Surfaci' view of Volroj'
showing cells in hexagonal Hjiaees in commoii jelly; n, iiuclens ; cr, con-
tractile vacuole. Very higlily niagnilied. (After Biitsclili.) e. Virtii-al
section of wall of Volvox ( x SUO). o, pair.-i of flagella. (After Colm.)

I 'olvoxglohator (Fi<!;s. 1 1 c, D, i-i), and IMate IXa. in the Case, occurs
at times in great almndance in ponds, even to the extent of giving a
green colonr to the water. The little organism, which is about 5'^ of
an inch in diameter, looks like a tiny green speck moving alumt in

16

C4UIDE TO THE CORAL GALLERY.

High Wall

Case

E. end of

Gallery.

Fig. 12.

the water (in a tumbler). On being magnified, the speck is seen to
be a spherical sac uniformly dotted with green points and progressing
by a peculiar revolving movement. Frequently the sphere con-
tains several green " daughter " spheres, and these, again, " grand-
daughter " spheres. The wall <jf the sphere is composed of a layer
of cells (the separate green points), each provided with two flagella.
The cells are embedded in a common jelly, each cell in a separate
compartment, but connected with its neighbours by radiating strands.
The outer surface of the sphere is covered with a pellicle through
which the pairs of flagella penetrate, and the interior is filled with
fluid in which daughter colonies may often be seen revolving. In
addition to a nucleus and contractile vacuole, the body of each cell
contains green chlorophyll granules. The daughter colonies inside
the sphere escape in due time by rupture of the outer wail of the

parent. Volvox is generally regarded by
botanists as a plant.

Gonmmpectorale (Fig. 11b), a colonial
organism belonging to the same family
as Volvox, forms flat plate-like colonies
composed of sixteen cells, each cell
having a pair of flagella at its upper
end. In one large section of Flagellata
the cell is provided at its upper end
with a collar, so the flagellum appears
to arise from the floor of a basin.
Codosiga cynisca (Plate IXa. in the Case)
forms a branching colony. Some of the
collared Flagellates secrete a horny cup or receptacle for the cell,
as in the solitary Salpingmca napiformis (Plate IXa. in the Case),
which forms a stalked horny cup containing the collared flagellate
cell. Proterospongia liaecJxli is a colonial form with Ama'ha-\i\Q
cells in addition to collared cells, all sunk in a common test.
The ancestor of the Sponges, which are unique among the Metazoa
in possessing collar-cells, was probably a collared Flagellate. The
MaU Coated Flagellata have a flattened body, with a longitudinal
groove from which a large flagellum projects, and usually, in addition,
a transverse groove with a flagellum lying in it. These forms are
mostly marine and often phosphorescent. Some species which have
a cuticular shell of cellulose, aud which contain chlorophyll, are
claimed by botanists as plants, but there are closely allied species
without the cellulose investment or the chlorophyll. O'eratium tripos

Noctiluca miliaris, tlie Phos-
phorescent Animalcule. Mag-
nified 150 diameters.

PROTOZOA OU SIMPLEST ANIMALS.

17

(Plate X. ill the Case) has a Hat triauf^ular hody wiih a spine at each Hij.h Wall
an<^lc. The two grooves form an iiiv<rted T-shape, the vertical bar *r.^^'
being very broad. The presence of eiha in the transverse band in (iallerv.
IMate X. is incorrect, there being simply a single flagellum lying in
the groove.

Ceratium is ]»hus[ihoresceiit,;uid in Lhe oiteu ueean is often funnd
united into chains of two to twenty individuals.

Nodiluca miUarls (Fig. \2) is a little peach-slmped organism
about 3V of an inch in diameter. A thick transversely-striated
" big flagellum " springs from the bottom of a deep groove on one

Fig. 13.

VorticeUa nehuli/em, a colonial lifll-.\iiimiilcule.
(Maguitied.) c i', contractile vacuole.

side of the body. Xear the groove is the mouth leading into a
cylindrical throat, in which is placed a second and smaller tlagcllum.
The body is invested by a firm cuticle, and the protuplasm in the
interior is vacuolated. See Plate XI. in the Case.

Noctiluca is highly phosphorescent, the light emanating cliiefiy
fi'oiii the protoplasm just beneath the cuticle.

.Marine phosphorescence is sometimes due entirely to the presence
<»f myriads of Xdr/ilifnr, which may be present in such al)undauce

18

GUIDE TO THE CORAL GALLERY.

High Wall

Case

E. end of

^.Gallery.

as to give a reddish colour to the surface of the sea in daytime. Tu
the Persian Gulf, a richly pigmented variety occasionally forms on
the surface of the sea brilliant scarlet bands, which extend for manv
miles.

CiLIATA.

The members of this group are characterised by the presence of
cilia on the surface of the body. These organs may form a spiral coil
round the anterior end of the body in relation to the mouth, or they
may be distributed over the whole or part of the surface of the body.
Garchesium polypinum (Plate XII. in the Case), which belongs to the
group of " Bell Animalcules," occurs in ponds in the form of bluish

Fig. 14.

Stentor polymorphus, tlie Trumpet Polypus. (Magnified.)

mucilaginous filmy patches on fresh-water plants, pieces of wood, &c.
The branching fan-shaped colony is highly contractile, and shrinks
into a spherical ball on being alarmed. Each individual has a
bell-shaped body seated on a stalk. The cilia, which form a
spiral fringe round the anterior end, set up a vortex in which food
particles are carried through the funnel-like mouth and gullet
situated inside the rim, and thence into the interior of the bodv.
VorticoUa nelndifera (Fig. 13) also forms colonies ; the figure shows
the individuals in various phases of contraction. Some species of
Bell Animalcules are solitary and do not form colonies. Stentor

PHOTOZOA OK M>n'Li:.ST ANIMALS.

19

Fig. 15.

polymorphus, the Truinpet PulypiLS (Fij(. 14), has a fimucl-shapetl High Wall

l)ody of gi'CL'D colour, cil)out ^j'- of an inch in lenj^th, and is usually *-;^'^

to be found singly or in t^roiips attached by the narrow eml to (jaUery?

duck-weed, sticks, &c. ; when swimniini^, the ortranism ehau<re.s its

shape cousideral^ly, becoming ovoid or

pear-shaped. The cilia are uniformly

distributed over the Avhole surface, but

form a spiral fringe of long cilia round

the anterior edge. See Plate Xllv.. 2.

in the Case.

Paramecium aare/ia, the Slipper
Animalcule (Plate XIIa., 1, in the
Case), has an oval flattened body with
cilia uniformly distributed over the
whole surface. Siyloni/chia (Fig. i:»)
has ciliu only on the under surface of the
flattened body; the thick spine-like oruaiis
are peculiarly modified cilia by means of
which the organism can stalk about.

ACINETARIA.

The body, in this group of Corticata,
is provided with tentacle-like organs in
place of cilia and flagella. Ikndrosoma
radians (Plate XIII. in the Case) is a
fresh-water Infusorian of rather large
size, attaining a height of iV of ^^ \niA\.
A fixed stolon gives rise to branching
ti'unks ; each branch terminates in
numerous suctorial knobbed tentacles,
which act by plunging into the bodies
of tluii' prey and sucking up the protoplasm. In the young stage,
Dendrosoma is free and provided with cilia, which disappear when
the animal becomes flxed.

Uijlontjchia mijlihi", the Musst-l-
Animalcule. Mnguified loO
(liaiuiters. a, laoutli; b, con-
Iractile vacuole; c, nucleus.

C. 1'

20 GUIDE TO THE CORAL GALLERY.

PORIFEEA [SPONGES].

[The High Cases are indicated by Roman numerals and the shelves of the

same by Arabic numerals.]

Introduction.

High Cases The term " sponge " is popularly associated solely with the soft

Table Cases elastic bath sponge, hut a glance at the Cases will show that, in

1 and 2 a, b. zoology, the word has a much wider meaning, some " sponges "

being of stony hardness, others leathery, others again like spun glass.

In life, the bath sponge is tough and fleshy, and covered with a
black skin (Case I., specimen in fluid). A section (Fig. 18) shows
a light-coloured flesh in which no trace of the horny skeleton,
commonly known as the sponge, is apparent ; to obtain this the
skin and flesh are macerated off, leaving the more resistant skeleton.

It would be instructive here to notice the glassy skeleton of
EupUctella aspergillum, or Yenus' Flower-Basket (Cases III. 2), aud a
complete specimen of the same in fluid (Table Case 2a) ; here again
the skeleton is concealed by the soft tissues. The dried specimen of
EuplecteUa imperialis (Case III. 3) shows the fluffy-looking soft
tissues above and the denuded skeleton below.

Many sp-jcimens, especially those in Cases lY.-VL, do not
materially ditt'er, excepting in colour, from their appearance in life.

The position of Sponges in the Animal Kingdom is above the
Protozoa or Simplest Animals and near the Coelentera (Zoophytes,
Corals, &c.).

To give some idea of the structure of a sponge, a brief account is
given of Ealkliondria imnkea, the Crumb-of -Bread Sponge, common
round the British coast (Case lY. 3).

This sponge forms yellow or greenish crusts on rocks, or shapeless
masses round the stems of sea-weeds. The surface of incrusting
specimens is usually covered with crater-like orifices termed oscules.
On closely observing living specimens in a large vessel of sea-water,
currents, rendered visible by debris, Avill be seen coming out of the
oscules ; a little indigo or carmine will serve to render the currents
still more apparent.

Fig. I.

Aphrocalligtes vuMu^^ ii Pictyimiiif S|M)ii;j;f, ^Oni-uuVfiitli iidtiiral .-i/i

..• .1. f y. .'».

POIUFEUA [srONGKS].

21

The origin nf these spons^e foimtains had always been a profounrl 1!
euij,'ma, whieh Dr. (iraut quaintly compared to that of the then.*
mysterious sources of the Nile. In lSi>r» the above-named zoulo^isi i
observed small particles beinj^ carried by currents through minute
PORES in the general surface of the Jfa/ir/ioiu/ria (Figs. i\ :5n) ; and
on account of the presence of these pores, he gave the name I'oiifera
to sponges. So much for the entrance and exit of currents : tu
ascertain their complete course and their cause, it is necessary U> cut
very thin slices of the sponge (Fig. 3). The pores ( Fig. :}nj lead
into spaces and channels, which are more or less branched, and which
Hnally arrive at the outer surface of groups of spherical cavities
termed flagellated or whi]) c;hambers, each jj-j of an inch in

Fig. 2.

Ilalichondria panicea (afteT Dr. Grant), n, pores ; e, oscule ; /, ova. Tlio out-
ward arrows show the currents escajDing by the oscules ; the inward ones
water entering the pores.

diameter, and with minute orifices in their walls. The whi]>
chambers open each by a comparatively large orifice into channels of
spaces ; these join with others to form larger and larger canals,
which terminate in an oscule. The whip chambers are lined with
'•collar-cells" (Fig. ?>('), each of which is provided with a tlagellum
or whip and a hyaline collar ; the beating of the whips sets up the
currents, which bring in food-particles and oxygenated sea-water, the
used-u]) water and debris being driven out through the oscules.
Food-particles are taken up bodily by the cells liiiim: the walls of
the canals and by the C(.)llar-cells ; but not much is known on this
subject at present. The ('.\NAL systk.m from the pon-s t "'
whip chambers is termed "in-current," and that fr"'" Mi' .,
chambers to the oscules "out-current."

22

GUIDE TO THE COEAL GALLERY.

High Cases
I.-VI. and
Table Cases
1 and 2 a, b.

Fig. 3.

A. Ilalicliondria panicea. Vertical section X 100. Partly diagrammatic.
a, oscule ; h, jiorcs ; c, whip chambers. B. Dermal membrane or skin with
pores X 100. c. Whip chamber X l,(jOO (after A'osmaer). d. Skeleton
spicule X 100.

roRiFERA [sponges]. 23

The boily substiuici', which is iK-riiK-atc'tl l»y tlie aitjal Ryst+rui, H
coiitciins iu the preseut species iiiiiiute needles nf silcx ( V'n:. Alt), }
each ^V of an inch in length, scattered rather irregularly throughout i
I he body tissues, ]>ut sonietiuies forming an oljscure scaflfcjlding. In
the skin, tlic needles are joined into bundles, which unite ai
their ends to form a network, in the meshes of whicii are gmups of
pores. The body-tissues are compcjsed of cells of various kinds, some
of which are concerned iu nutrition, others in secreting the skeleton ;
others, again, line the surface of the canals and of the b(Mly.

At certain seasons the body develops egg-cells, which, after
fertilisation, form little oval ciliated embryos ; these swim about f(»r
a day or two, settle down, and become s{iongL'S, the ciliated cells
becoming collar-cells. The organism, being unaljle to roam in
search of food, sets up currents which convey food to it.

HaJkhondria is a Siliceous Sponge belonging to the order Mon-
axonida, because its skeleton is composed solely of siliceous spicules
having one axis.

A very brief account of one of the simplest sponges may help
further to elucidate the structure of these organisms. The Cal-
careous Sponge, (Jlathrina blanca (Fig. 4) and Case 2a, in its earliest
stage forms a minute thin-walled sac opening at the summit by tlic
oscule. The interior of the sac is lined with collar-cells, and the
wall is perforated by fine pores. Currents enter through the jtorcs
and leave by the oscule. The thin wall is supjtorted by three-rayed
spicules of carbonate of lime. The canal system is here in its
simplest form. In Sijcon ciliaftim (Table Case '2a) the wall of
the sac gives off horizontally arranged tubular pockets, which alone
are lined with collar-cells. A piece of the inner wall of the large
specimen of tSyco/i rammyi (2a) shows the honeycomb-like openings
of the tubes.

Classification.

The composition and structure of the skeleton alb>rd the most
reliable characters for the classification of Sponges. The skeleton is
composed either of calcium carbonate, silica, or horny material
usually in the form of hbre. The calcium carbonate and silica arc.
for the most part, seci-eted in the form of simculks. whii-h may Ik*
separate or fused together. A few sponges do not form a skeleton,
A simple scheme of classifi('ation is given Itelow : —

Class 1. ('AL('.\l;lv\. Calcareous Sponges. Skeleton cal'ureons.

24

GUIDE TO THE CORAL GALLERY.

High Cases Class 11. SILICEA (^sUex, flint). Skeleton siliceous, horny, or

I.-YI. and absent.

Table Cases
1 and 2 a, b.

Fis. 4

A. Clathrina hianca X 20. b. The same x 80 (partly diagrammafic). rt.oscule;
6, pores; c, spicules ; f?, portion of wall turned back. c. Transverse section
of sponge (diagrammatic). D. A tiiree-rayed spicule X 300 diameters.
K. Collar cells x 1,200 diameters. (After E. A. Minchin.)

Note. — In Fig. B, the spicules ought not to have been drawn close up to the
margin of the oscule ; also the figure is too broad and the pores far too large.

Sub-Class [. Hexactinellida (/^e^-, six ; «Ms,ray). Six-Ray or
Glass Sponges. Siliceous spicules typically with three axes and six rays.

PORIFEKA [sponges]. 25

Sub-Class II. Dkmosi'oxcm; {<h'iiiii<, imiltkude), inchuliii^ all )(■ -^ ' -m-s
sponges other than Calcarea and llfxaftinellhla. ' '

Grade I. Tetractinkllida (/^-^v/, fdur ; a/rti.s,n\\). F«jnr-Uav ,
or Anchor 8pon,ii:es. Siliceous siticules ty[)ically with four axes and
four rays ; also certain fleshy sponges (("arnosa) are includt-d here.

Grade II. Moxaxonida (wo/?o.<t, single ; (i.roii, axis). Monaxon
Sponges. Siliceous spicules rod- or pin-shaped.

Grade III. Keratosa (/f^m.s, horn). Horny Sponges. Skeleton
of horny fibre.

Grade IV. Myxospongida (»/y.m, slime). Slime Sponges. With-
out a skeleton.

Class I. ("ALCAREA [Calcareous Sponges].

The Calcareous Sponges form a comparatively small group, only TabloCa-
about 2ii() recent species being known. They live for the must ^wrt
in shallow water, and prefer shady sheltered localities.

The skeleton is composed of spicules of carbonate of lime, which
are either separate, or, in a few instances, fused into a solid frame-
work. The spicules are either three-rayed, four-rayed. necdle-shapL-d,
or, in one instance, spherulitic.

The Asconidcc, which are the simplest of all spunges, are formed
of thill-walled branching tubes, lined with collar-cells throughout
their inner surface. The tubular branches may be separate {Leuro-
solenia), or may join to form a network {C'l/'thn'na).

In the Syconidir tlic collar-cells are restricted to "radial tubes"
surrounding a central cavity devoid of collar-cells.

The beautiful Ciliated Sycon {S'l/ron ci/iafin/i) is one of the
commonest sponges round our coasts, where it is found attached tu
rocks and seaweeds. This sponge, which is usually about an inch in
height, has the form of a little oval white sac with a silvery crown (»f
spicules round the orifice (uscule). The crown of spicules is fully
expanded when currents are passing through, but otherwise it is
closed. The wall of the sai- is formetl of horizontally ariimgeil
closely-packed tubes each opening by a comparatively wide aperture
into the vertical central cavity, but ending blindly on the outer
surface of the sponge. Currents i>ass through microscopic orifices
in the walls of the radial tubes into the inU-rior of those tul>es and
into the central cavity, and finally leave through the oscnle.

A very large specimen of a Sycon Sponge, over eight inches in
length, from Poole Ilaibour. is exhibited in the Case.

2fj GUIDE TO THE COEAL GALLERY.

TableCase2A. The Compressed Grantia {Grantia compressa), which forms com-
pressed sacs resembling little paper bags, is also common round the
British coast.

Sub-Class I. Hexactinellida [Slx-Ray or Glass Sponges].
High Case The Hexactinellida, which include many remarkable and beau-

TTT

Table Case ^^'^^ forms, nearly all come from great depths, ranging from DO to
2 A, B. 0,000 fathoms.

The SKELETON is built up of siliceous spicules, each typically
possessing three axes and six rays, or of spicules derived from this
type ; three bars of equal length crossing each other at right angles
through a common centre would give the typical form of a regular
six-rayed spicule. Endless modifications of this form occur ; the
rays may be curved or branched, or one or more of the rays may
disappear, giving rise to five-rayed, four-rayed, three-rayed, two-
rayed, or one-rayed forms (Fig. 7). The spicules may be roughly
grouped into two kinds — large " skeleton " spicules, which form the
bulk of the framework, and scattered flesh-spicules of microscopic
size.

The SOFT TISSUES are arranged as follows : in the wall of a
typical cup-shaped Hexactinellid, a layer of relatively large thimble-
shaped whip chambers is separated from an outer dermal and
an inner gastral membrane by loose reticulate tissue. Currents
always enter by the dermal membrane, pass through the convex
surfaces of the whip chambers, and leave through the gastral
membrane. The large central cavity, so often present, is termed
the gastral cavity. Hexactinellida are divided into two sub-orders.

Sub-Order I. Lyssacina. In this group the skeleton spicules
are separate throughout life, or, in cases where they are more or less
fused in later life, were separate in early stages.

EupJecteUa aspergiUum, or Yenus' Flower-Basket (Figs. 5, G ;
and specimens in Case III. 2, and Table Case 2a), forms an elegant
cornucopia-shaped skeleton, now often seen as an ornament. In life
the skeleton is concealed by a gelatinous flesh. The lattice-like frame-
work of the skeleton is formed of longitudinal, transverse and oblique
strands, the last forming the prominent ridges on the surface ; the
strands are built up of the fused rays of very large four-rayed and three-
rayed spicules. At the lower end is a matted tuft of spicules, by means
of which the sponge is rooted in the mud. A surface layer of separate
sword-shaped spicules, each with its handle tipped with a lovely little

Fig. 5.

EuplfictiUa ImperiiilU (to the left) and K. ttoiHrqiUnm (Voiiiis' Flnwi-r-ItiukuO.

(One-sixth nntunil sl/f.)

n»/an* /I, M.

I''lO. tJ

<.■•-">..

b

EuplvcAeWa iispcrtiillinu. A. Section uf a lidgc iiml part >>t' wull :•, !.">. <t. iK-mial
layer; ?;, flagellated cliamhers; r. gashal nivity; </, iiMtiilh'sof s\v.)r<|-.sliii|*t!
spicules each ti|>pe<l with a floriconic. n. Ri-Kiihir six-rnycil spicule x I<m*.
c. Floiicomc spicule x 8(10. (After F. K. Schnizc.)

r,. fiw i>. 2«.

POIUFKUA [sponges].

27

" floricoine ■" spicule, is cliar.icteri.stic uf Eiiplecivllid Six.ng.-fi ( Fij^. Cc ). h.^...
The peculiar circiihu- holes in the wtill of tiie spuujre aihiw of din- •**
communication between the outside and the interior. Tlie lai

Fig. 7.

<•

Spicules of Glass Sponges (magnified). In the centre u notle cf the Dictyonine mtwork «f n

Yentriculito Sponge.

,i;astral cavity is clused at the sniiiniit hyasieve-plate. K. (is/HTi/illuin
is obtained from a depth of '.•<> fathdms n(T Cilni, IMiilippines. The
ma<^nificcnt Kuiilortella inijicrialis (Fiij. .'» ; and 8i)eciinens in

28

GUIDE TO THE COKAL GALLERY.

High Case

III.

Table Case

2 A, B.

f\/v

vv.

1

Fig. 8. Case III. ?>) comes from Japan. Specimens of the

two species have been photographed together for
comparison.

The fine specimen of Walteria JeiicJcarti, from
Sagami Bay, Japan (Fig. 9 ; and Case III. 3),
consists of a long hollow thick- walled tube rising
from a solid base, and with solid pinnate branches
arising from the tube at right angles ; the oval
sharp-edged openings in the wall of the tube are
oscules. The little elevations on the surface of
the branches are caused by a commensal zoophyte.
Rhahdocalyptvs victor (Fig. 10) and specimen in
Case III. 3, from the same locality as the previous
species, forms a deep thin-walled vase of felt-like
texture.

The Ijeautiful Lace Sponge, Semferella schnltzei
(specimens in Case III. 1, and Table Case 2b),
has a straight or curved conico-cylindrical body
terminating below in a massive root-tuft. The
surface shows a delicate gauze-like network, the
dermal membrane (Fig. 11), and also long bands
and patches of coarser pattern ; the latter are sieve-
plates covering the oscules. In place of a simple
central cavity with one terminal oscule and sieve-
plate, as in Venus' Flower-Basket, there is a main
central cavity giving off lateral branching tubes,
the surface-openings of which are covered with the
sieve-plates ; accordingly currents enter the fine
gauze-like areas and leave by the coarser sieve-
plate areas.

Hijalonema sieboldU, or the Glass-rope Sponge

(Figs. 8, 12) and specimen in Case III. 3, comes

from Japan, closely allied species, however, being

widely distributed. When the glass ropes (without

the upper portion of the sponge) first arrived in

Europe, they were supposed to be either artificial

productions or the axial coxe of Gorgonid Corals.

The twisted strand or glass rope is a root-tuft

composed of immensely long spicules, which root

the sponge in the mud, and which, at the upper

end, project like a spike into the interior of the

y sponge-body. Some of the long spicules end in a

Lower end of a spi- toothed disk, and are provided along their length
cule of the glass
rope maguified.
a, axial canals of
five aborted rays.

a

Flo. 9.

WnUeri'a lenchirti. An Kiipl. ctclliil Spoiigo. (Otn-hixtli imtumi x'ltv.)

r>< fticr ft, V,

Fig. 10.

Til fan IK 28.

Fi.:. II.

Surface network oi Semptn^ld Dchnllzii, the l.ace SiMin^i-,
(XiltUllll size.)

T»_facr ): S».

Fio, 12.

llijdliimma 8ii'.bi>ldii, Mu; GliiH.-i-liopu S|Hii(rr(.. (Onofourtli iintnrul 8izi>.)

N'OTK. — A cnist of I'ahjthna.a zoophyte iissociaU-d with tliit) spoiifjo, liml unfor-
tunately become; ihtnchcd from the iiiii)er eiul of llif " (;hiKti-l{o|H'." mul
is not sliown in tlic illustrivtinn.

Tu fad ft. 3»

rouiFi:RA [sponges]. 29

with ii SL'iTatL'd spii-ul ri<l:re with tUc- teeth j)oiiitinj^ upwards Hiji" • --
(Fig. 8). ,^J^^

The body ot the spouire fi)rins u thick-w.dled cup, which, huw- -
ever, is so loosely constructed that lii^ht cuu he seen througii it. The
interior is divided up by four to eight vertical partitiuns radiating
from a central spike, 'i'he top of the cup is closed by a thin sieve-
j)late with perforated "quarters" corresponding tu the divisions
inside. A ''commensal "' zoophyte {Palijtlnxi) is always fitund
investing the upper end of the glass rope, and occasionally it forms
pits (often mistaken for oscules) on the surface of the spojige itself.
Unfortunately the Pahjthoa has become detached from the npj)er
part of tlie root-tuft of the specimen figured, but is abundant on the
surface of the sponge body. The Japanese deep-sea shark-fishers
obtain the sponge by means of hooks attached to their de.'p-.«ea lines.
By a curions parallel, the deep-sea shark-fishers of Portugal obtjiin a
nearly allied species of Hyalniiema in somewhat the same manner.

Ldpliocalijx phUippinensis, from Cebu (in fluid. Table Cjise :i.\),
which forms a small compact thick-walled cup with long root-tufts,
furnishes a beautiful example of bud formation, buds of ;ill ages
being present on the specimens.

Sub-Order II. Dictyoxixa. In this group the skeleton, even in
the earliest stages, forms a rigid framework constructed of the fused
rays of large regular six-rayed spicules. These sponges usually have
a vitreous, finely honeycombed appearance. The magnificent
A]jhroc((Ilist/'s r<(f<fiix (Fig. 1), in the centre of Case HI., is shaped
like a vase with a thick stem, and with large folds projecting out
from the walls. The very line specimen of ('honchisma rali/j-, to tlie
right of the former, is bowl-shaped, and with finger-like p )ckets
often extending down, like the "ro;)ts" of a Banyan tree, till they
reach the base on wliich the spougc is growing. The fossil Ventri-
culites common in flints from the Chalk are Dictyonine 8p mges.'

CLASS III.— DE.M0SP0XC1.K (»U CO.M.MoN Si'().\(iKS.
The Common Sponges include all sponges other than the
Calcareous and Glass Sponges.

Tetuactixellida (Four-Ray Si'ox«i ks).
The sponges of this Order are often spherical with a radiating Hinl>C*so IV.
structure (CranieUn, \\ . ;;), or they may form tough leathi-ry cakts [^.'^*j'^'^''^.^

* A later classification of Hcxactincllida l)y Prof. F. E. Schulzc is iiito

two 8ul)-orders: (1) JTf.nistrropliuni {hwhuUun Diet i/oii inn) with hoxiistor tlosh
spicules, and ('I) Aini'liuliscojilioni wilh AntjiltulisLs. See fpriKlit VMc
Case .\, c'oluniiia (l and 7.

lum.

30

GUIDE TO THE COEAL GALLERY.

Partition.

Fig. 13.

iigh Case IV. with a conspicuous rind {Gydonium japonicum, IV. 4), or rigid
E^igl^>. plates or masses of stony hardness {CoralUstes hoicerhanld, lY. 4).

The Order is divided into two groups, the Choristida with separate

spicules, and the Litliistidii
with peculiar " desma " spi-
cules, which are usually articu-
lated to form a rigid stony
skeleton. Some species possess
" caltrop " spicules, with four
axes and four rays. The most
characteristic spicule, liowever,
is the trident, with a long
shaft and three prongs, which
may project forwards or be
bent backwards or outwards
(Fig. 13). The tridents are
arranged with the shafts point-
iug inwards and the prongs
spreading tangentially beneath
the surface or projecting out-
wards. Tridents and needles
in varying proportions often
form thick radiating bundles.

The Geodine Sponges { Geo-
dia, Cydonium) possess a thick
outer crust or rind, composed
of solid globular spicules
(Fig. 14). The "desmas" of
Lithistid Sponges are formed
by the deposition of concentric
layers of silica round a minute
rod or caltrop ; on this nucleus
there arise nodulated branches,
which articulate with the
branches of other desmas to
form a rigid framework. In
addition to the "skeleton"
spicules, there occur in this
Order very minute S-shaped,
spiral, and stellate flesh-spi-
the affinities of the

Trident spicules of Tetractiuellid Sponges.
(Magniiied 200 diameters.)

cules, which are of great aid
various species.

in

determining

PORIFERA [sroXGKs].

31

Cahxosa or Flksiiv Si'OXCKS.

The sponges of this small gnnip fither hiive ui> hard skeleton at CaAo IV. :i.
all (ClioniJrosia), or merely scattered stellate spicules {('lunuhiUn).
They possess a well-marked rind iiiclusiiig a softer "pith," and tin'
canal system is highly developed.

Chondrosia re/iifoiini^, or the S-'u-Kidney (Case IV. :i), hns a

Fio. H.

. ..W

'W^,

Section of Geodia sliowinjr crust of ^'lobular spicnlcs, radiatiiifj buniUes of
triileiits and needlus, and .small star-shap-jd \\^.^i\\ spicules. Maj,'iiific<l .''O
diameters. (After Bowerbank.)

smooth rounded surface, on which one or two small circular «>.scnlos
are present; the mnnerous jxtres are not visihle to the naked eye.
The sponge, being devoid of a hard skeleton, shrinks greatly when
dried, but swells up again on being immersed in fluid. Apart from
the absence of trident spicules and of a hard skeleton, tiie Carno.sji
show many ailiuities with the Kour-iiay Sjionges.

32 GUIDE TO THE CORAL GALLERY.

MON AXON IDA (MONAXON SpONGES).

High Cases T^jg Order contains by far the laro:est nnmber of species. The

IV -VI • •

skeleton-spicnles are uniaxial, i.e., shaped like rods, like needles

pointed at one or both ends, or like pins ; six-rayed and four -rayed
spicules never occur. The spicules may be scattered or united into
bundles, and may form radiating or reticulate scaffoldings. Flesh-
spicules may or may not be present, one of the most common forms
being buckle-shaped (Fig. 17). The huge Neptune's Cup Sponges,
Poterion 'patera (on pedestals), from the East Indies, are among the
largest of Sponge forms ; the skeleton is composed of a dense net-
work of bundles of pin-shaped spicules.

The large specimen of Poterion. placed above the Hexactinellid
Case, and formed of three trays one above the other, belongs to a
closely allied species.

The Boring Sponges, which also have pin-shaped skeleton
spicules, are remarkable for their habit of boring into shells and
limestone.

Gliona celata (Case IV. 3) is very common in oyster shells, in
which it excavates extensive lobed galleries ; the oscules and groups
of pores are situated on conical elevations which project through
small holes in the surface of the shell. Vigorous specimens burst
through the shell and form large cork-like masses (Case IV. 3),
the identity of which with the boring portion was for a long time
unsuspected. The magnificent specimen of Caulospongia verticillata
(Fig. 1.5 ; Case IV. 2) has a thick main stem branching into three,
the stems giving rise to closely-set whorls (or spirals) of thin lamellae
gradually diminishing in size from below upwards.

The massive Suherites icilsoni (Case IV. 3) is remarkable for its
brilliant purple colour. The colouring matter forms a rich purple
solution in acidified alcohol. Esjwriopsis ciiollengeri (Fig. 16), from
82") fathoms, east of Celebes (specimen in fluid, Case IV. 4), one of
the " Challenger " treasures, has a main stem giving off along one
edge a series of stalked bowl-shaped fronds increasing in size from
below upwards. The in-current pores are situated in the concavity,
and the minute oscules on the convex surface of each bowl.

The series of specimens of Echinonema typicum (Case IV. 4)
shows well the great variation in form that may occur in one and
the same species.

Fresh-water Sponges (Case VI. 3, facing west) are common

Fi.:. ir..

Caiilogpongia verficUltiln. A IMoimxdiiiil Sponp'. (One-Bi>viiitli iiuUirnl ^ixe.';

r.i laa p. 31.

!

Fin. 10.

Esperiopfi.t chdUtiKjeri. A .Munuxonid S]>un;;e. < 'i'wo-thinls imtnrHl s>izi>.)
The figure oil tliu Icit sliows osciiliir, and tlmt on tlio riijht, |K>nil bUrfHCi-8 of

till' upoULri! Iriillft.s.

Til fact i>. 3X

lM(i 17.

Siliceous spicules of Monaxonid SponROM. (Mnjiiiilit'il 'J00-,HOO iliunioleru )

I)

34

GUIDE TO THE CORAL GALLERY.

High Cases
IV.-VI.

in lakes and rivers attached to stems of reeds or the piles of locks, &c.
These sponges are often of a bright green colour, and are easily
mistaken for Avaterweeds. The green colour, which is due to the
presence of chlorophyll, does not occur in specimens living in shady
places, the sponges then being pale buff. Alcohol dissolves out the
colour, forming a clear green solution.

Spongilla lacustris forms green crusts from which long digitate
branches arise.

Tlie black Parmula hatesii (Case YI. 3), from the Amazons, is
often found attached to branches of trees submerged during the rainy
season, the sponges being left high and dry when the floods subside.

Many fresh-water sponges produce little seed-like buds or
gemmules, which possess a hard resistant capsule perforated by a
pore at one point. "When the favourable season arrives, the contents
of the gemmule ])urst through the pore and develop into a sponge.

In the Clialinid Sponges (Cases Y., YI.), the skeleton forms a
network of horny fibres cored by siliceous spicules ; if the latter
were absent from the fibres, the sponges would be Horny Sponges,
and it is generally supposed that the pure horny sponges have been
derived from siliceous forms which no longer secrete silex.

High Cases
I. II. and
Table Case 1.

Keratosa (Horny Sponges).

The Horny Sponges possess a skeleton of horny fibres, which
generally form a close network, as in the Bath Sponges, or the fibres
may branch in a tree-like manner. Yery commonly, foreign bodies,
such as sand grains, the spicules of other spouges, &c., are present in
the body of the sponge or in the axis of the fibres ; even in the
finest bath sponges there are scattered sand grains in the main
fibres.

A series of commercial sponges is set out in Case I. and Table
Case I.

The Fine Turkey '^])o\\gQ,Spongia officinalis (Fig. 18), has a cup-
shaped body with a black or dark skin. The oscides are situated on
the floor of the cup. A section of the body shows a comparatively
uniform pale yellow surface, the canals being slightly darker in tint.
Groups of pores on the outer surface lead by short fine canals into
spaces just below the skin ; from the floor of these spaces canals pass
inwards, branching and gradually diminishing in size, till they reach
groups of pear-shaped whip chambers, with the cavities of which they
communicate through minute orifices in the walls of the latter.

PORIFEHA [sponges].

35

Groups of whip chambers h;ad eacli h\ a short passjige into a coiumon i
channel, which joins with other canaliculi to form caiiaLi, tina!
opening by the oscules. The whip «haml«.'i-8 form a sort of
cordon between the extreme rootlets of th<- in-current and vwt-
current canals.

The horny skeleton, which is imbedded in and which supix)rts
the tissues of tiie body, forms a netwurk composcil of radiatiiii.;
main fibres connected by a dense meshwork of finer stcondary
fibres.

The Common Bath Sponfre, Ifij>ji(isjHj,(i/ta Kjuina, has a massive
cake-shaped body covered with black or dark skin. The body ig
permeated by wide channels and cavities separated from eacii other by

Fig. is.

J0T<5

^^^i*\

it-

?s:--r

?\

1-5
I. -".

K;"

k.

e' d' ^d r

A B C

Toilet Sponge, a. Diagram of Canal System, u. Section allowing <i, pores ;
h, canals ; c, whip-chaiubers ; d. skeleton fibres ; d\ main fibre ; e, embryo.
C. Whip-chambers. Highly iimgnified. (Afti^r 1\ Iv Sfhiilze.)

thin walls. The Common Hath Sponge is, in fact, composed of
contorted lamellae separated by lal)yrintliine spaces (Fig. lit) ; the
large holes on the surface are not oscules, but " i>scudoscnIi-s,'' the
true oscules and groups of pores being scattered indiscriminately over
the surface of the lamellae or walls of the spaces. Ciu'rents always
come out of a true oscule, but they may enter or leave by the h(»les
on the surface of, the Common Batli Sponge. See specimens in fluid
ill Case I.

On the floor. of Case I. is a Ijrokeu pitcher with the skeletons of
a bath sponge and fine toilet sponge growing on it. '

T\iQ S'j)o /Iff ia simofca, or Hard Sponge, which forms a third s|Hri»-s

1) 1'

J

36

GUIDE TO THE CORAL GALLERY.

High Cases
I. II. and
Table Case 1.

of commercial sponge, has a flat disk-shaped body with numerous
oscules on the upper surface.

The Levant Lappet, which is a variety of Spongia officinalis,
forms huge thin flaps like an elephant's ear ; occasionally the edges
of the flap unite to form a capacious funnel-shaped cup.

The above three species {8. officinalis, S. zimocca, and H. equina)
include numerous varieties and variations which need not be, further
alluded to here.

Commercial Sponges flourish in sub-tropical and tropical waters in
depths of 2 to 100 fathoms, the world's supply coming almost entirely

Fig. 19.

Section of Hippospongia equina, the Common Bath Sponge. (Natural size.)

from the West Indies and eastern- half of the Mediterranean. In the
latter region they are collected by divers, who descend naked or in
diving-dresses, or by men who hook up specimens by means of a
long harpoon ; dredges are employed in deeper waters. In the West
Indies (Florida, Bahamas, &c.) the hooking method is employed, 'a
bucket with a pane of glass in the bottom being used as a sul^marine
spy-glass to do away with the effect of the surface ripples.

Sponges are prepared for market by macerating them in sea-
water in staked enclosures ; after a few days the skin and flesh rot
off, and can then be beaten out ; the skeletons are hung ' up in
strings to dry and bleach in the air and sun.

PORIFERA [sponges]. 37

Sponges are sometimes cultivated from euttinp*, care Ixriu*; taken HLh f;
that a portion of the skiu is retained iu each piecr. It take« alx)iit J
seven years for a cubic inch of sponge to grow to a niarkctahle size.

Attention is directed to the gigantic Luffaria arrfuri, Xeptunt-V
Trumpet (Case II.), from Yucatan, and to the fine fan-hhaiM.-d
8])ecimen oi Iaiithella//abelltfonius\tviu-:i{\i it (Ca.se II.) ; the skeleton
fibres in these sponges are comparatively thick and core<l with a
tliick pith, those of the bath sponges being solid, or with only a
slender core of pith. The specimen of J^/ti/lloxpviujiu foHasrens
(Case II. 4) shows a curious likeness to a Turbinarian eoml, the
oscnles of the sponge resemljliug the calicles of the coral ; but it
is uncertain whether these resemblances have any real signitiejiuce.

Myxospoxgiua or Slime Sponges comprise a small group
characterised by the entire absence of a skeleton. Hulisdna forms
yellowish-brown slimy crusts on stones.

[A series of specimens and diagrams illustrating the structure of
Sponges is exhibited in an u[)righi table case at the eastern end of
the Coral Gallery.]

38 GUIDE TO THE CORAL GALLERY.

HYDROZOA.

[(*) An asterisk against names of species denotes that specimens in fluid
are exhibited in the upright part of Table Case 3.]

Introduction.

The exhibited collection of Hydrozoa occupies Cases 2-i at the
eastern end of the Coral Gallery.

The members of the class occur as fixed plant-like forms often of
horny texture {Serhdai'ia, &c., Case 3), or as massive or branched
coral-like growths {Sfylaster and MiiUjJora, Cases 2, 4), or as
transparent free-swimming bell- or disk-shaped organisms, which
may l3e simple (Medusa' or Jelly-Fisl), Case 3), or may form colonies
composed of variously modified individuals {Sijjhonophora, Case 3).
The vast majority of species are marine, but a few live in fresh
water.

The specimens in Case 3 a, b, closely resemble dried seaweeds, but
can generally be distinguished from plants by observing, especially
with a lens, that a serrated appearance of the branches is due to
little horny cups or receptacles ; see, for instance, Diphasia tamarisca*
which has unusually large cylindrical cups. In life, each cup
contains a polyp with a crown of tentacles surrounding a mouth
opening into a stomach cavity.

In spite of great differences in form amongst the Hydrozoa, a
comparatively simple plan of organisation can be traced in all.

To briefly explain this, an account is given of Hijdra or the
Fresh- Water Polyp, a tiny Hydrozoon which lives in ponds attached
to water-weeds (Fig. 1a). Hydra, which is green or reddish-brown
in colour, according to the species, attains an average height of
about one-third of an inch. The little creature alters its shape
considerably, being now contracted down to a lump, now expanded
into a little column with a circle of thread-like tentacles near the
summit. When a tentacle touches some small organism, the latter
is paralysed and drawn into the mouth at the top of the column,
and thence into the simple stomach-cavity, where it is digested, the
remains being evacuated by the mouth. Between the mouth and

HYDROZOA.

39

the circle of tentacles is an area terineil the hypostuim.- (Fitr. In, /<y//. j.
The animal is a simple sac, the wall of whi<;h is formed of two biyei-s
of cells, an outer or ectoderm layer, one or more cells deep, and ;iii
inner or cndoderm layer, one cell deep (Fij(. In, ed. end.), the lavere
being separated by a thin strnetureless lamella (Fiir. 1, nis. i/l.).

I'l.;. 1.

A. Hydra on pond weed, slightly enlarged. (I'roin ualuri'.) ii. Section of
Hydra, highly magnified, mth. moutli ; hyp, hypostnme : ent. cac, 8toriiat>li ;
end, endodtmi ; ect, ectoderm; msgl, strnotun-less liinii'lln; l>il 1, •_'. Inula:
OB)/, ovary : .s'^jf/, spermary ; «/c, thread cell. (.Mtcr I'urker and Ilnswell.)
c. Thread cell, very highly magnitied. (After 1' Iv Schulze.)

The endoderm, which lines tlie whole inner cavity and i he interior
of the tentacles, is concerned in tlie di;^'estion of food. In t.hc
ectoderm are certain peculiar cells, each contaiiiinir a cyst with u
barbed thread coiled up inside (Fig- '^) > '^ point<.'d procc-^s pro-
jecting from the outer surface of the cell acts :is ;i triirjfcr, which.

40 GUIDE TO THE COEAL GALLERY.

on being touched, causes tlie barbed thread to be everted, thereby
stinging and poisoning the prey. Thread-cells are characteristic of
the Coelentera. Hydra reproduces itself sexually by means of eggs,
which form in little wart-like swellings on the surface ; or asexually,
by forming buds which grow out from the wall, develop mouth and
tentacles, and normally become detached. Hydra, which is named
after the monster of the fable, can be cut into pieces, and, condition-
ally on containing a portion of the two cell layers, each fragment
will develop into a complete animal.

Classification.

Having given a brief outline of the structm'e of one of the
simplest forms, an account will now be given of the groups of
Hydrozoa, which, for convenience of description, will be referred to
under the three headings : —

I. Hydroida (Hydroid Zoophytes).

II. Hydrocorallinae (Coral-like Hydrozoa).

III. Medusa? and other allied free-swimming forms (Jelly-Fish,
Siphonophora, and Ctenophora or Comb-Jellies).

I. HYDROIDA (HYDROID ZOOPHYTES).

The horny plant-like growths in Case 3 a, b, have fundamentally
the same structure as the Hydra. If the little sac were to form a
horny protective cover on its surface, to become longer, to give off
buds, which likewise budded, all the buds remaining in connection
with each other, and each surmounted by its crown of tentacles — a
plant-Hke Hydroid colony would be the result. BougainviUea
fruficosa* (Figs. 2, 3, and specimen in Case 3) is a branching Hydroid
colony, every branch terminating in a polyp, as each individual of a
colony is termed. All the polyps are vitally connected with each other
by the common living tissues inside the stems. The polyps are of two
kinds, one kind being in the form of an elongated sac or tube with a
crown of tentacles, that is to say, like Hydra ; Avhile the other, when
mature, resembles a small Medusa or Jelly-Fish. The Medusa-like
polyp (Fig. 4) ultimately becomes detached and swims away. The
little free-swimming polyp, which we must now call a Medusa, is bell-
shaped ; the true mouth, which leads into the stomach, is at the end
of the clapper (manubrium) hanging down from the centre of the

HYDROZOA.

■II

concavity of the bell or " umbrella " ; four radial i-analK pass from C%m 3,
the central stomach to open into a circular canal round the margin
of the umbrella ; from the same mart'lu are suspended four [jairt of
tentacles, each tentacle beini; provided at its base with an eye-sjxjt.
The opening of the umljrelhi is i)artly closed by a narrow circular
baud, the veil or velum, extendiug in from the rim ; and, most
important of all, the eggs are situated in the walls of the manubrium.
The organism swims by alternate contraction and ndaxation of the
umbrella.

The little ^ledusa is simply an extremely modified polyp, sjK'cially

Fi.;. 2.'

-^^:

^^m^^-^

Colony of BougainvilJea fruticosa, natural size, nttached to the underside of a
piece of floating timber. (After AUman.)

adapted for a free-swimming existence. If a Hi/(ha were shorteue<l
and drawn out laterally (Fig. 5), a shape somewhat like that of a
jMedusa would result. The ^Medusa has nervous and muscular
apparatus and sense organs in correspoudence with its a<-tive
existence, these being absent in tlie fixed polyps.

A colony of Bouoamrillea, then, is uiade up of indivitluals of two
kinds, feeding or nutritive polyps, whose function it is to obtain aud
digest food for the colony, aud generative polyps, whose funetion it
is to form and carry the eggs. Here we have division of lal)our, and

' From " Encycloi)a.Hlia Britannieu.

42

GUIDE TO THE CORAL GALLERY.

corresponding alteration of form (dimorphism) among the units of
the colony.

The fertilised egg of the Medusa develops into the fixed Hydroid
colony, the latter forming buds in which the eggs are produced.
This is an instance of alternation of generations, a phenomenon very
common among the Hydrozoa, but especially marked in cases where
the asexually formed generative polyp or individual becomes detached
and swims away.

Fig. 3.1

Portion of a colony of BougainviUea fruticosa, magnified. (After

AUman.)

In cases where the generative polyps are free-swimming, advan-
tage would result from the eggs being scattered over a wide area, and
not crowded in the neighbourhood of the parent stock ; and, further,
the egg-carrying polyp (Medusa) can swim to the surface where food
is plentiful. The free generative polyp, or Medusa of ClavateUa
prolifera (Fig. 6), shows a transition between a feeding polyp and
Medusa. The umbrella can scarcely be said to exist in this case, the

^ From " Encyclopaedia Britannica."

lIYDItOZOA.

43

I-'i.;. 4.

Meilusii l)C'iiiiJ- unablo to swim, luit (jiily ('apaljlc of creepiu}^ about on (.a,<: >,
its peculiar tentacles.

Free-swimuiin«; geuerative polyps or Medusiu occur only in some
Hydroifls ; in many species the geuerative polyps remain on the
colony and produce the eggs in this situation ; in such tiiSf« they
lose, to a greater or less extent, their Medusan strnctun.- and may l>e
reduced to a mere wart (Fig. 7 ).

Generative polyps may arise from the stem as in Buwjaiiii'Ulm,
but very commonly they arise from the sides of a degenerate feeding
poly}) which has lost its mouth and tentacles, and is then termed a
blastostyle ; the latter, with its buds, may be naked ( Ifi/ilnirfuiui,
Fig. i>), or invested with a horny capsule {Sertularia, Fig. Vl uh).

The Hydroida are divided into two
groups — Athecata and Thecaphora.

Athecata (or Gymnohladed-Anlho-
mechisce). In this group the feeding
polyps cannot be withdrawn into horny
cups, and the generative i>olyps or
buds are not enclosed in horny capsules.
The ^ledusffi (Authomedusa') form the
eggs in the walls of the manubrium.
Tuhularia i/idivisa* or the "Tubular
Coralline like Oaten Pipes " of Ellis, forms
clusters of simple stems from six to
twelve inches in height, rising from a
twisted mass of roots. Each stem, in
life, is crowned with a red flower-like
polyp with two sets of filiform tentacles,
one set being near the mouth and the
other at the base ; festoons of stalked
generative polyps or buds hang down
from the base of the feeding polyp.
Each Ijud contains a degenerate Medusa,

which never escapes to lead a free life, but produces the eggs in its
attached situation. The fertilised egg develops iiuo a peculiar embryo,
whir-li becomes fixed and grows up into a long-stenuned polyp.

Tuhularia larijnx* has branched annulated stems. The aj-punut
branches on T. indivisa arise from embryos settling (»n the oMer

stems.

The fine specimen of Peniuiriu ruroluiii* from .Nai-l-s^ hm'u^ .i
branching colony, the polyps of wlii.'h possess a ring of liliform

Free generntivi- i>i)ly|> or
!Mi(lu8ii of Jiougahiril-
ha frutirosa. a. iimiiu-
briutn; b, nuUal cftimls;
c, vellum ; d, nuked eyi-
spots. (After Allmtui )

44

GUIDE TO THE COEAL GALLERY.

Fig. 5.

Case 3, tentacles at the base and scattered knobbed tentacles above. The

two kinds of tentacles can be clearly seen in this specimen with the
aid of a simple lens.

Hydractinia echinata* (Figs. 8, 9) is always found forming a white
fleecy covering on univalve shells inhabited by Hermit Crabs. " The
waving forest of tall and graceful polypites generally reaches its
greatest height towards the mouth (of the shell), round the edge of

which are set the curious snake-
like appendages. Intermingling
with the perfect polypites are the
rudimentary zooids, which carry
the generative sacs, attenuated by
their work and looking as if
weighed down by their burden"
(Hincks). The polyps rise from a
chitinous crust covered with conical
serrated spines.

Monocauliis imijerator * (Fig.
10), one of the most remarkable
acquisitions of the ChaJlenger Expe-
dition, was obtained from depths
of 1,875 and 2,900 fathoms in
the North Pacific. A naked stem
over seven feet in length, and
bulbous at the lower end, is sur-
mounted by a large polyp with
basal and oral circles of filiform
tentacles. The polyp was pale

(loniitudiual section); B, of a Hy- Pi^^k, and measured nme mches m

droid Medusa, o, mouth ; g, gastric breadth across the expanded basal

cavity; «, tentacle; s?, structureless • . . tpntaolps Tlie exhibited

lamella; g', jelly between ectoderm ^^^^^^ ^I tentacles. xne exniOlteti

and endoderm ; rk, radial canal ; specimen (Case 3) is sadly altered
^, velum ;W/.- circular canal. (From f^.^j^ ^^.j^.-^l- |,. ^^^g |^ YlIq; but, as
Lang s Text-book ComiJ. Anat. J

Sir AVyville Thompson observed,

" these delicate things, drawn up rapidly through the water from a

depth of four statute miles, suffer greatly from this violent change."

The specimens almost seemed to melt away, and had to be
promptly put into alcohol, which has hardened and contracted them
to their present condition.

Cordylopltora lacustris* is* a fresh-water Hydroid, with branches
rising from a creeping stolon to a height of two or three inches ;

A. Din gram of a Hydroid feeding polyp

HYDROZOA.

45

the polyps are ovoid and provided with scjittered eiiform . ..^ a,
tentacles.

The dried specimens of Ceratella and Cliitina in Case 3a arc-
composed of a dense network of horny tubes. In life the surface of
the branches is covend with large club-shaped polyps provided with
scattered knobbed tentacles.

Thecaphoha (or Oali//itob/us(ea-Lepto)imhi.s(r}. This group in-
cludes many of the more familiar forms of zoophytes (Case 3 a, u).

Fill. •;.

A. Clavatdla proUfera (magnified) ; at base, clusters of generative polyps, one of
which is nearly ready to become detached, n. Free creeping generative jwilyp
or Medusa, highly magnified ; 6, tiie siime slightly eiihirged. (Afti-r Hincks.)

The feeding polyps can be retracted into horny cups, and the
generative polyps (which are budded off from a blastostyle, and
which may be fixed or free-swimming) are enclosed in a horny
capsule. The MedustB (Leptomednsa') develop the eggs in the
radial canals. There are three sub-groups — the Campanuhiriua,
with stalked cups, the Sertularina, witli sessile cups, and thi' IMuinu-
larina, in which occur little supplementary cups i-alled nematophore-s
containing an offshoot from the common body substance of the
coloiiv loaded with thread-cells.

4«

GUIDE TO THE CORAL GALLERY,

Case 3. Ohelia longissima* (Obelia sp., Fig. n) forms veiy slender

branching - stems ; the cups are borne on ringed pedicels, and
resemble wineglasses. Tlie generative polyps, which are borne on a
blastostyle, become free Meduste.* The latter are tiny crystal bells
with numerous tentacles and with eight litho-cysts ; they often swim
with the umbrella everted and the manubrium projecting from the
centre of the convexity.

Case 3a. Sertularia abietina, the Sea Fir Zoophyte (Fig. 12, and specimen

in Case ;3a), forms clusters of brown pinnately-branched stems from six
to twelve inches in height. It is often seen among heaps of seaweed
on the shore, or attached to oyster and scallop shells in fishmongers'
shops ; the rather large horny cups, which are arranged alternately on

Fig. 7.

Diagrams illustrating the gradual degeneration of the Medusa bud into
a mere rounded swelling. The black represents the stomach and its
continuations ; the lighter shading represents the reproductive cells.
A. Attached Medusa ; b. The same with margin of umbrella closed
over manubrium ; o, D, e, further stages. (After Lankester, Encyc.
Britannica.)

each side of the branches, are swollen at the base and narrowed at the
circular orifice. The oval reproductive capsules are slightly stalked.

Case 3a. Sertularia argenfea* or the Squirrel's Tail Zoophyte, S. cupressina,

the Sea Cypress, and Thidaria tlmja, the Bottle Brush Coralline, are
■all expressively named by Ellis from their general appearance. In
these species the sessile cups are arranged alternately on opposite
sides of the branches. In UydraUmania fakata, the Sickle Coralline,
the cups are on one side only. In the five species above referred
to the generative polyps (or degenerate Medusge) are permanently
attached to a degenerate feeding polyp or blastostyle, the whole
being enclosed in a horny capsule.

Case 3b, Antemiidaria anfejinina, the " Lobster's Horn Coralline, or Sea

Beard"* (Fig. 13, and specimen in Case 3b), forms long jointed

llVlJl;nZ()A.

47

stems giving off whorls of slender hniuohleta bearing the uiiuutecui^ ^^ 3b.
and still more minute funnel-shaped ueniatophores.

.1. ramom (Case 3b) has la-anched stems.

lu Ar/laop/ieniapJunia, the '• Podded Corallin<-." ihe r. ' ..

capsules are protected by a i>od-shaped receptacle formed i i.. ,i

brauchlets which curve round and meet.

Af/Jaophenia itrens* from .Java, is named on account of its severe
stiuo-iuy properties. Some species of this genus living in the tropi.s
attain a height of several feet, and it is dangerous to come in contact
with them.

Fig. 8.

\

'J>

\.''

Hydractinia echinata on a shell of a whelk inhabited l>y a Hermit Crab.

(Natural size.)

II. HYDROCORALLIN^ OR CORAL-LIKE IIYDROZOA.

The Hydrozoa of this group rescmlile the Reef Corals in forming Cases 2, 4.
a calcareous skeleton ; indeed, the Hydrocorallinie were sup|K.»«tl
to belong to the same class (Authozoa) jis the Corals, till Aga^-i
showed that Millepora was a true Hydrozoon. Iiat<r, ^losi-Uy. in his
classical work on the Challenger HydrocoralliuiV, confirmed Agassiz'
results, and proved that the Sti/lostiridip- were also Hydrozoa. In
all the llydrocorallines two forms of polpys (Fig. It!) occur, viz..
gastrozooids, with nioutli and stomach, and teniaclc-likc dactylo-
zooids without a mouth ; the gastrozooids are contained in pit>

Fig. y.

Hydractinia echinata. a, feeding polyps ; h, reproductive polyps
(female). (Maguitied.)

IIVDROZOA,

VJ

termed gastropores, ami the ductylozooids in sinuU.r pits u-rined daclv- ,. i,,- i
lopores, the pores being usually arranged in systems (Figs. i:. and Ik").

M1LLEFOHID.E. Milhpora forms massive laminate or Ijraudied Caws 4.
growths, and presents a great variety of forms ; but, according Uj Prof.
Hickson, there are no defiiiiti' speeific characters separating one form
from another, and consequently we nuist regard the forty or more
so-called species as mere variations of only one species, viz., Jlillejjuru

Fi.;. 10.

. *.

Monocaulus imperator. upper third. (Much reduced.)

alricornis,ov the Stag's Horn Millepora. He would call, for instance,
Jf. rcrrurom (Case 4, upriglit portion) JA. (/hirin/iis,fiu-.[vs>. nm/rnsa.
It seems that an eml)rv<i settUiig down on a broad surface with
room to spread forms a laminate growth, such as the typical .]f.
alckornis or M. complavata (Case 4) ; but if it settles on a small
o])jectit tends to forma branching growth. JA///^/wv/ often encrusts
old bottles, &c. ; in Case ?>\ a delicate network of Fan ( '<>ral is exhilMt4'<l
coated with a thin crust of Mi/I^'/>oni ti/rironiis. Systems consisting
of small gastropores, surrounded by irregnlar circl--^ .■'" •d'om six still

K

Fig. 11.

A. Ohelia. b c d. Medusse of same (c, everted). hU,
blastostyle ; coe, common body tissues ; ect, end, ecto
and endoderm ; ent, stomach ; gth, generative cap-
sules; hth, horny cups, I, lithocyst ; mhd, Medust
bud ; mnh, manubrium ; p, horny outer covering ;
P 1,2,3, feeding polyps; rad. c, radial canal; t.
tentacle ; v, velum. (After Parker and Haswell.)

Fi<;. 12

I il^i'" -^•^r.y;'-'

Sertularin ahielhia. a. Sliglitly enlir^^ctl. u niunolilct mu^nithHl ; «i, |>«ily|>!i;
b, ro[)ro(lnctivc fapsule (orifi:iniil). Tho orilii-i-H on ri>;lit 8i<l« of Fig. It urr>
closeii by horny lids.

52

GUIDE TO THE CORAL GALLERY.

Case 4. smaller dactylopores, can be seen scattered over the surface of these

corals. A section shows in the cavities of the calicles series of

Fig. 13.

Antennularia antenruna. A. Natural size. b. Joint of stem with brauchleU luagui-
lied; m, polyp; b, uematophore ; c, reproductive capsule, c. Branclilet highh
magnified (lettering as before). (After Allman.)

parallel floors (tabulae) marking successive stages of growth activity.
MUlepora is richly provided with thread-cells, which retain their

3

a
O

c

^

To face p. 53.

HYDUOZOA.

1m. i. 15.

Case 4.

efficicucy even on old dried specimens. The degenerate dactylozooids Cumo *.
have a number of capitate tentacles, while the giustruzotiids have only
a whorl of four (Fiij. 1(1).

In isoi Prof, llickson discovered the male, and in Ihkh the
female ^ledusa (Fig. 17) of Jlillpjiont in small «;apsules, which. «lien
occurring near tlie surface, form rounded swellings (auiiiulhu.*).
Latterly, ^Ir. Duerden has seen the living Medu.sae in his aquarium
ut Jamaica. This tiny Medusa is only about -^^ inch in diameter ;
its cavity is nearly filled up by the large manubrium containing the
eggs. The umbrella is devoid of canals, tentacles, and sense-organs,
but is provided with batteries of thread-
cells ; and usually no mouth can be
seen at the end of the manul)riuni.
The little creature, however, is able to
swim away with its heavy burden t)f
eggs from the parent colony ; having
deposited the eggs, it shrivels up.

STYLASTEiiiDiE. In this family the
dactylozooids are without tentacles, and
one or both kinds of zooids are supported
in their calicles by a calcareotis style.
There are several genera in this family.

In Stijlaster the pores are arranged
in " cyclo-systems " — a circle of dacty-
lopores surrounding a central gastropore.
A cyclo-system presents a deceptive
resemblance to the calicle of an ordinary

coral ; in the latter the calicle contains one coral polyp, but in the
cyclo-system there are a do/.en or more degenerate individuals sur-
rounding a central individual; the dactylozooi<ls were formerly
supposed to be tlie tentacles of the central zooid. The generative
buds, which are situated in the often numerous swellings or ampullae,
never become free Medusa3.

The Stylasters are remarkable for the elegance and beauty of
their arborescent fan-shaped forms (Fig. 1 0 and tluir excjuisiie
colouring. Several specimens of Stylastir rosn/s from off a cable
from the West Indies show considerable variation in colour, l»eing
white, rose-pink, and salmon-colouicd. The cyclo-systems regularly
alternate on the sides of the slendri- liraiu-hes.

Fragment f>f MiUfMtra, sluiw-
ing the cirdcB otcmctyloporeu
each with 11 coiitnil p;a8tri>|>->rf .
(Twice natural size.) (After
Mosolev.)

' From •' Kucyclopivdia Brituniiiea."

54

GUIDE TO THE CORAL GALLERY.

Case 2 c, d.

Stylaster sangtiineus, or the " Blood Coral " from the Pacific
Islands, is of a brilliant red colour.

In Astylus (Fig. 18) the cyclo-systems all face one way. Crypto-
he/ia pudica is remarkable for the little canopy which arches over
each cyclo-system.

I)istichoj)ora has the pores arranged in a triple row along each
edge of the flattened branches, a central row of gastropores being
enclosed between two parallel rows of dactylopores. Probably the
various supposed species of Distichopora {D. coccinea, violacea, livida)
are colour variations of one species.

Fig. 16.'

Enlarged view of the surface of a liviDg Millepora, showing five dactylopore
polyps surrounding a central gastropore polyp. (After Moseley.)

III. MEDUSiE AND OTHER ALLIED FEEE-SWIMMING

CCELENTERA.

Case 3, Glass models of Medusae or Sea-Nettles are exhibited in

pai . ^j^g upright part of Case 3 along with specimens in spirit. Medusse

have already been referred to in the account of Hydroida and

of Millepora, where it was stated that in some species certain

polyps carrying the eggs (generative polyps) became detached

' From " Encyclopaedia Britannica.'

IIVDROZUA. r»o

from the p;ireut colony and swam away. In ibc <asf oi uian\
Medusif, the eggs develop directly into Medusie, m. fixed su^^e "
being known ; here the Hxed stage, which there is reason to iK-lieve
has at one time existed in every case, has been *' hnrried throuj^h "
ill the egg. Medusai present two very dilVereut types of structure :
in (me, which may be called the " llydr<jmediis;in" type, the
umbrella is provided with a velum, tiie sense-organs are naked on
the umbrella margin (Naked-Eyed MediLsic), and the liied stock,
when known, is of the Hydra or Hydroid tyi»e, and jirtxluceg buds
laterally. Mediisaj of this type come under the sub-cla.ss Hydro-
mediisce, which includes Hydroida and Hydrocora/liiue.

In Medusa? of the second or " Scyphomedusan " tyjK.- tlie

Fi.;. 17.'

'I\V

((

fK

J

Female Medusa of ^lillepora, showing the eggs Am] lunrginal batteries
of thread cells. (After Prof. S. J. Hickson.)

uml)rella is without a velum, the marginal sense-organs are coventl
by little lappets (Covered-Eyed Medusse), rows of " ga.stml fila-
ments" project into the stomach cavity, and the fixed stock. t»nly
known in a few cases, is a broad flattened polyp (8cyphi.stt)ma ^),
which produces buds by transverse fission (Fig. IHa-c), ami has four Case :i.
longitudinal ridges along the walls of the stomach cavity, Scypho- '^ l"""^''' I'*'"'*
medusan Medusa? are included in the sub-class Sryp/iumpdu.str.

HYDROMEni'SAX ^IeduS/E. The tiny ^fedusiv given otT fnun the
fixed stocks of llydroid Zoo])hytcs come under two groups. Tliose

' From " Proceedings^ of the Koyal Society."
- Skup]ios, a cup ; sto7na, mouth.

56

GUIDE TO THE CORAL GALLERY.

Fig. 18.'

Case 3, detached from the flower -like stocks of Athecate Hjdroids come
Upright part, ^^mjei- tj^e Anthomedusa- ; they have naked eye-spots (Fig. 4), and

the eggs are formed in the walls of the manubrimn ; see RathTcea
fasckulata* a little Medusa which is given off from a small solitary

fixed polyp with four tentacles. The early history of Pamlcm

ronira* and Tiara pileata* both of which are Anthomediim, is

unknown.

The Medusae of the Thecate Hydroids come under the Leptomedusa,

(see Ohelia* Case 3, and Model of Wwjmatodes thaJassina) ; the eggs

are formed in the radial canals, and the sense-
organs are either eye-spots or " litho-cysts,"
the latter being vesicles containing a hard
concretion which transmits impressions from
the outside to delicate " auditory " cells. In
certain Hydromedimc the sense-organs arise
on modified tentacles known as tentaculo-cysts.
These forms, which come under Haeckel's
Orders Trachomedusd' and Narcomedusce, have
no known " Hydroid history," and in some
cases are known to develop direct from the
Qg^ ; see Car marina hastata (Fig. 20), and
Model in Case 3a. Two fresh-water Medusfe
are known, both of which are Hydromedusif
Limnocodiwn sotrerUi, from the Victoria Regia
Tank in the Royal Botanical Society's Gardens,
has a shallow umbrella less than half an inch
in diameter and with numerous tentacles ;
the fixed pliase occurs as a columnar polyp
about a quarter of an inch in height, simple
or branched once or twice ; medusa buds
arise from the summit ; the original habitat
was probably the Amazon region. The second
species, Limnocnida tamjamjica, comes from
Lake Tanganyika; the umbrella is about
an inch across, the manubrium is very

wide and shallow, and the stomach-cavity is nearly filled up by

the convex lens-like central area of the under surface of the

umbrella.
Case 3, Finally the Medusaj of Millepora and the swimming-bells, &c., of

Upright part. ^^^^ Siphonophora belong to the Hydromedusan type.

ScYPHOMEDUSAN IMedusj^. {Scyphomedusce). These include the

Portion of Astylus show-
ing cyclosy stems each
with a central gas-
tropore and zone of
slite-like dact\ lopores.
(After ^Moseley )

Vic. 19.

Life history of Aimliu. a. " llijihit lulm" on hIh-II (Soypliifitoiim xtmn") i>. i'
Tlic Siiinc niidcr^nin^' trunsviisr divihinii (ciiliirf^'i-tl) n i>'. Kplivm »t«)j<'
(natural hizc and <iilar^,'('(l). i v.'. Ynunj,' Aiirrlin (iiiitnml i«ix«« Hiul
onlargnil). F. Fully-trrmvii AnnUn.

rn/«ct ft. M.

r

HYDROZOA.

0<

liii-irer aud commoiior kinds of Jelly- Fi.sh or Sca-Nuttles. A brief
accouut is ,ij:ivL'ii below of Aurelia unrita* (Model and sjK-eimenH ' 1
in Case 3), whose phantom disks are so often seen in summer
time slowly swimmiutr below the surface. In the centre of the
shallow umbrella are four pur[)le horsesh(»e-sliai»ed or circular
generative masses ; in the centre of the under surface is the
manubrium prolon<jred into four arms ; the maririn of the und»ri-lla
is provided with a fringe of very short line tentacles, the uniformity

Fig. 20.

Carmarina hitstata,one of the Truchomeduxx. (After Haeckel, and from Kncve.

Britannicii.)

of the fringe being l)rokeu by eight notches, each containing
a teutaculo-cyst ; each of tlie latter (Fig. 21) is covered by a _ Tuso a.
pair of minute lappets, hence Medusre of this ty])e were called ^ "'■'>^''' !'
Covered-Eyed ; while those of the Ilydronicdusan tyjK', being
without lappets, were called Naked- Kyed.

The thickness of the umbrella is traversed by a .system of simple
and brauclied canals, which pass from tlu' central stomach to a
circular canal running round the margin of the uud)relln. Pro-

58

GUIDE TO THE CORAL GALLERY.

Case 3, jecting from the stomach walls are four groups of gastral filaments.
Upright part, loaded with thread-cells. The purple reproductive masses project
from the floor of the stomach cavity ; at the hase of the manubrium
outside are four pockets, which bring the water very near to these
masses. Aurelia has no velum in the adult state. The fertilised
egg develops into a hollow oval ciliated embryo, which settles down
and becomes a small polyp with mouth and stomach and sixteen
tentacles ; this phase was formerly supposed to be a distinct
individual, which was named Hydra tuba, or the Trumpet Polypus.
A very fine example sent by the Plymouth Biological Station i&
exhibited in Case 3 (Fig. 19a), numerous specimens of the little

Fig. 21.

EvJL

ML

Ent / . V Qc

Con , 2"

Teiitaculocyst and margiual lappets of Aurelia aurita. In the left-hand figure
— m?, marginal lappets; f, tentnculocyst ; «, superior olfactory pit ; wf. mar-
ginal tentacles of the disc, magnified about 50 diameters. In ihe riglit-
hand figure — o, superior olfactory pit; h, inferior olfactory pit; It. hood or
bridge joining the marginal lappets ; t, tentaculocyst ; cmi, auditory con-
cretion; oc, ocellus. (After Eimer, from Encyc. Britannica.)

polyp being attached to a shell ; this fixed phase of Aurelia is now
called the " Scyphistoma " stage, on account of the shallow cup-
like oral region, contrasting in this respect with the elongated narrow
conical oral region of Hydra and Hydroid polyps. In course of
time the little Scyphistoma undergoes " transverse fission," and
resembles a pile of saucers with crenulated rims (Fig. 19b).
Presently the saucers detach themselves (specimens, Case 3) and
swim away ; they are now known as Ephyra Medusas, or the
Ephyra stage (Fig. 19c ; specimens. Case 3) ; the last stage in this
wonderful transformation consists in the filling in of the spaces
between the eight bifid arms of the Ephyra and the development of

HYKROZOA.

59

II fringe of fiuc tentacles on those invervening portions, the '-•■'- *"
the bifid arms now occupying the notches in the rim ami f
the lappets of the sense-organs ; the medusa is now recognisahle ob
Aurelia.

The fixed Scyphistoma stage is not common, many Sovpho-
medusiii developing direct from the egir. The Scyphometliwa.' art-
divided into four Orders. The first Order ineludes the exceptional
Lwernarm-Haliclystus {Lucernaria) octorudi<itus * (Fig. 22) is shaf>ed
like a vase with a short stem. The upper edge is produced into
eight arms each crowned with a tuft of tentacles. The animal,
which fixes itself by its stalk, can creep along or swim. On the
margin, between the tufts of tentacles, are peculiar modified tentacles
known as anchoring bodies, which assist progression by sticking to
and grasping the surface of the sea-weeds or stones. The mouth

Fi<i. "22.

Haliclyitus octnnidlatu^, a Luceriiariaii ^rcdusn. ou sea weed, a, mouth
and stomach ; h, tentacles; c. ancliors; d, ivprodiictive glands. ( I-'mm
JoliDston's British Zoophytes ; tigurea slightly altered.

and stomach (manubrium) are in the centre. Haliclystus, which is
commonly found adhering to sea-weeds, varies in colour, being olive-
brown, green, or pink. The second Order (Discomedusae) includes
the commoner kinds of Jelly-Fish, Polagia, Aurelia, Pilema, ('»ty-
lorkiza, &c. (see Case 3). In Pilema (Fig. 23) and other " Khizu-
stomatous" forms the lips and arms of the manubrium are fuseil
together, and the food, consisting of minute marine organisms, is
taken in through little suctorial mouths and conveyed up lomr
canals. Pilema odojms* is fairly common. Si)eciniens often attain
a diameter of two feet. The greenish umbrella has a purple frill-
like margin : there are eight tentaculo-cysts with their sjxoial
lappets, i)ut there are no tentacles round the margin of th.-
umbrella. Tlie large mouthless manubrium breaks up into eight
long arms often attaining a length of two feet; the minute.

I'pright pari.

60

GUIDE TO THE CORAL GALLERY,

Case 3, almost microscopic suctorial mouths armed with fine tentacles
Upright part, ^^ig, 24c) are abundant in the cauliflower-like regions of the arms.
Very commonly small fish are found associated with the larger
Medusae, which doubtless shelter their proteges and enable them to
dodge out of the way of their enemies. The majority of known
Medusffi do not live at any great depth, but a few forms inhabit
the deeper zones of the ocean.

Fig. 23.

srnlh

Pilema, a Rhizostome Medusa, a. entire animal (diminished), b, vertical section,
c, one of the suctorial moutlis. c, arm canal; gf, gastral filaments; gon, egrgs ;
or.a, oral arms ; rad.c, radial canals ; s.mth, suctorial mouths ; st, stomach ; t I,t2,t3.
tentacles on oral arms. (After Cuvier, Glaus and Huxley; from Parker and Haswell's
Zoology.)

SiPHONOPHORA.

The members of this group are free-swimming colonial Hydrozoa,

in which the individuals composing the colony are modified in

various ways according to the work they perform.

„ g In Physophora (Fig. 24c), for example (see Models and speci-

Upright part, men in Case 3), a hollow stem or siphon is provided at its upper

end with a small air-sac, below which follows series of swimming-

I

HYDKOZOA.

«J1

bells, mednsa-liko iudividiuilK, each consistiui,' simply «.f an Dn.i.r.i! .
and adapted solely for swimminjr ; next folltiws a whorl uf .

Ki... 24.

Floating colonies of Siphimophoni. a. Diphynxtimpninihilii. n. Agn>u|>
of appeii(l!i<;es from tlie steiu «\ Jh'plii/es. c {F\<i. on ri^lit ). l^lnjnojihora
hijdrostatica. D. Swiiiiiiiing-liell nltlu' siinie. e. (.'liistor of jjoui'nitivi
buds (dfgonerate iiii'dusfc) of Aij>ihHii. <(, stem of colony ; n', uir
sac; //(, ssviiuniiii'^-ljell ; t-, cuncavity of Biiino; r, radial ainulo;
0, orifice of umbrella ; t, covering pieces in u, tentacle-like jnilypa in c ;
7J, stomach ; i, tentacles; j/. generative l)ndt*. (Alter licgeulmtir, fntin
Eneyc. Uritaiiiiii'a.)

" coverino-pit'ces/'aiid below this a chister ul' nieiliisa-likc irenenUivt-
polyps, teutaclc-likc polyps ami short -stalked feediiii,' jiolyps, eaeli of

62

GUIDE TO THE CORAL GALLERY.

Case 3, the last having attached to its stalk a long tentacle armed with
Upright part, thread-cells.

In Physalia, the " Portuguese Man-of-War " (Fig. 25), the air-

FiG. 25.

cr

I

Physalia floating on the surface ; cr, crest ; p, a polyp ; pn, air sac. (After
Huxley; from Parker and Haawell's Zoology.)

sac takes the form of a large pear-shaped bladder provided with a
many-chambered crest ; a mass of generative buds and feeding polyps
with long tentacles is suspended from the under surface of the

HYDUOZOA. t)3

float ; tht'i-c iire no swimiuiug-bells ur coveriuir-pif -cs. Physalia
pela/ica (Model, Case 3) has one loiijr siout main a-ntacle and ''P
numerous lesser ones; Garavella* (Model, Case 8) has mimerouij
large tentacles. The fli)at is borne wholly above the surfa*;.-, and w
carried alon^^ by the breeze with the broad end foremost and the
teuLacles trailing behind. Prof. Agassi/, saw specimens with tentacles
over fifty feet in length. I'hysalia is notorious fur its dangerous
stinging properties.^

Rkodalia niiranda* is a deep-sea Siplujiiophoran, woiidi-rfully
adapted for living at great depths ; the depressed oval air-sac i«
followed by several circles of swimming-bells eiich attache<l by a
broad vertical lamella to the stem.

A curiously modified swimming-bell, the aurophore, allows of
communication between the air-sac and the water ; by emptying or
secreting the air or gas the aiiimil can sink or rise within certain
limits without using its swimming-bells. The " stem " is not a
delicate tubular siphon as in Phi/sopkoni, but forms a thick raiuss
permeated by canals, the feeding poly[)s with tentacles and irenerative
buds being attached to its lower siu'face.

^lost of the swimming-bells and all the tentacles have become
detached in the specimen, the red colour of which is artificial ;
but the air-sac and massive stem are well preserved. The specimens
were obtained by the Ghallenger from a depth of (iou fathoms in
the South Atlantic.

Diplitjes * (Fig. 21 a, li), which is without an air-sac, lias two Cajie :\.
swimming-bells, and below these groups of covering-pieces, feeding ^"^ ^'^'^'
polyps, and generative buds situated along the stem.

In Velella* or " By-the-wind Sailer " (Case 3), a vertical semi-
circular "sail "is attached diagonally across the upper surface of
an oblong disk : attached to the lower surface of the latter are one
large central feeding polyp and circles of smaller feeding polyps,
generative buds, and a marginal fringe of tentacles. Fleets of
Velella sailing along in the breeze are more commonly seen in
warm latitudes, but specimens, b!)th of I'rlflla and PlujsnUa, have
been found off the soulli-west coasts of England.

Poi-jil'a * consists only of a circidar ilisk with its (le[>endent polyps
and tentacles.

' Mrs. David mentions in her book on Funafuti that the natives aro more
afraid of Phijsalia than they are of the sharks.

64

GUIDE TO THE CORAL GALLERY..

Ctenophora (Comb-Jellies).

Case 3, Ctenophora are free-swimming Coelentera \\ hich never form

colonies. The body, usually oval or spheroidal, is provided with
eight rows of swimming-plates situated along eight meridians, each

Hormiplwra plumosa. a, mouth ; 6, swimming plates. (After Chun.)

plate consisting of a comb-like band of very large cilia. The mouth,
situated at the oral pole, leads into a gullet and stomach, whence
canals proceed to run beneath the swimming-plates ; canals also
pass upwards from the stomach to the aboral pole, where they open

HYDllOZOA.

05

to the exterior ou each side of a eentnilly-i»lact'cl " amlitory " or
bahiiiciu<i; sense-organ.

Some Ctenophorans are provided witli a pair of phimose teuiaeles,
which can be retracted into receptacles. Honnipltora plumomi •
(Fig. 20) has a small peiir-shaped ])i)dy, the mouth Ijeing at the
narrow end : the eight rows of swiinmimr-plat -s ueeiipy aljout two-
thirds of the length of the boily ; a pair i)f luiig feathery teutaclen
can be emitted from two tentacle-sheaths, which open one ou each
side of the body not far fi'oin the :il)oral pole.

Gestus reneris, or "Venus' (Jirdle" * (Fig, 27), has a long l)and-
sliaped body, which may attain a length of several feet ; the mi>utli
is in the centre of the lower l)()rder, and the gullet and st<»iiiacli
occupy quite a narrow area in the centre of the band ; the eiirht

Vic. 27.

I'

rrttk t

B

Ce%tm veneris, a, adult, b, younjj. mth, inoutli ; /. teiitucles ; //. liitiml
tentacles ; spV. one of the tour short rows of swimming plates ; xiil', 'Hi.-
of the four long rows of swimming plates. (After Chun ; from Parkir
and Haswell's Zoology.)

rows of swimming-plates form an apparently continuous line ou each
edge of the upper border. The young ( 'est us is spheroidal. Itut soon
Ijecomes compressed in a vertical i)laue and lengthened out.

Cesttfs swims mainly by the wavy and serpentine motion of its
body. The small exhibited specimen shows the aboral border, with
its apparently continuous rows of swimming-plates nearest the front

of the glass.

Bf'ioe omta* from Naples is in the form of a large sju- with a
wide mouth ; the cavity of the sac is, strictly speaking, the gullet,
the stomach occupying only a small space at the base,

JJeroi'- orata can alter its shape to a remarkable extent while
swimming, being now V-shaped with widely-gaping lips, now
U-shaped ; tiie crealure is extremely vorai-ious. and can tak.- into il,s

66 GUIDE TO THE CORAL GALLERY.

Case 3, capacious gullet animals that at first sight appear bigger than
Upright part, j^gg^f ^

The Ctenophora are now usually regarded as a distinct class of
Coelentera.

Classification of Hydeozoa.
(From Prof. Lankester's Article Hydrozoa, Encydopcedia Britannica.)

Class Hydrozoa.

I

Sub-clasB HydromeduBK Sub-class Scyphomedusaj

I

I I i I II

Orders Gymnoblastea Calyptoblastea Trachomedusre. Narcomedusaj. Hydrocorallinse. Siphonopbora.

or Athecata. or Thecaphora.

[The Coelentera have been divided, in the various recent classifi-
cations, into two classes, Hydrozoa and Anthozoa ; into three,
Hydrozoa, Anthozoa, and Ctenophora ; or, again, into four,
Hydrozoa, Scyphozoa, Anthozoa, and Ctenophora.]

( f^T )

ANTIIn/(».\.

The existing Anthozou ai'e cunstructt-d ou diic of two tyiMrs ;
they either have eight tentacles and no more, or, like the eouimou
Sea-Anemone, they have a number of tentacles. Where there arc
only eight tentacles, as in the noble red coral, each is fringed at its
sides, or, in technical terms, is pinnate ; when the tentacles are
numerous they are non-pinnate. A certain number of iwilaeozoic
corals had a symmetry of four, ^^'e may therefore speak of Tetra-
coralla,^ Hexacoralla,'^ and Octocoralla.^

Both of tlie latter may have (i.) soft bodies without si)icule.s, (ii.)
horuy axes (horny corals), (iii.) a continuous limestone skeleton
(stony corals) ; the Alcyouaria may have scattered spicules.

The Hexacoralla, or Zoautharia, commence at the eastern end of
the Gallery, next the Hydrozoa ; the Octocoralla, or Aleyonaria.
commence at the western end of the Gallery.

The organisation of the Alcyonaria is illustrated by lars^e
diagrams ; the first, that of Moiuu-enid danrini, is very possijjly ludy
a larval stage of some Alcyouarian ; Ijut it shows some of the
essential characters of the group. These are a sac-like Itody, with
an axial gastric cavity, giving oft" eight compartments, on the
partition walls of which are developed the gonads or reprtKluctive
elements.

The organism seldom remains single ; developing a .stolon or
creeping process, it gives rise to bud after bud, and so forms a
colony, as in Clavulffria (Figs. 1 and 2) or Alri/o/iiiun (Fig. ;{).
diagrams of whicli are shown. There arc also some excellent wau-r-
colour sketches of Clavulariaus taken from life, and presented by
Prof. Ilicksou, F.R.S.

The creeping process or stolon is well seen in tlie small i.rei>a-
ratiou of the organ-pipe coral {Titbqiora) ; as shown in Fig. I, this
is seen to be a small flat plate, from which ihe tulM?s are beginuiui?
to rise up.

' Sivc Rugosa. * Sivc Zoantharia. ' '^"'■' M.-V'-muhi.

68 GUIDE TO THE COKAL GALLERY.

The tissues seldom remain soft ; they become impregnated with
horny matter or with carbonate of lime, or both. The horny skeleton
is continuous ; the calcareous consists of separate spicules more or
less closely packed.

The differences at different ages in the amount of lime deposited
are well shown by the fine series of specimens of Isis (Case 14).
Colonies formed by budding and provided with a skeleton may
become of great length, as Juncella, or of great intricacy of inter-
lacement, as Gorgonella ; the fine GorgonelJa verriculata from Zanzi-
bar should be noticed ; often tliey are of exquisite beauty, as the
Calligorgia from Mauritius (Fig. 5) or the Hooherella from South
Japan suffice to show. Sometimes there is a continuous skeleton, as
in the noble red coral of the Mediterranean, good specimens of
which, showing the coral polyps expanded, and explanatory diagrams
of which are exhibited in Case 13.

A particularly dense skeleton is developed in Heliopora (Fig. 6),
the only living member of a group (Coenothecalia) which formed a
large part of the coral fauna of Palaeozoic times. Long considered
to be a Zoantharian, the affinities of Heliopora to the Alcyonaria
were demonstrated by the late H. N". Moseley during the voyage of
H.M.S. Challenger. This skeleton is remarkable for being always of a
blue colour when collected on a reef ; but, as Mr. Stanley Gardiner's
collections show, the blue colour gets progressively paler as specimens
are obtained from deeper and deeper water.

In other Alrgonaria a reduction of the skeleton seems to have
occurred, so that the axis is friable and breaks up into scattered
spicules ; this is the case with Paragorgia arhorea, a fine example of
which from the coast of Norway is shown with an illustrative
drawing as it appears during life, and a well preserved piece with
the polyps partly extended.

In the Pennatididae reduction goes still farther, and little is left
ill the way of a skeleton save a horny axis, which extends along
the whole of the colony ; a striking example is to be seen in the
specimen of Osteocella on the south wall of the Gallery.

Fine examples of Pennahila, Fimintlina, and others are shown,
as well as two beautiful plates of UmlelluJa encrimis, taken from the
Report of the Norwegian North Sea Expedition. The curiously
modified and kidney-shaped Renilla should be noticed.

The general plan of the structure of the Octocoralla is shown by
Mr. Berjeau's water-colour drawing in the Gallery, which is shown,
reduced to a third, in the accompanying figure (Fig. 7), where we

ANTIIOZOA. 69

remark the miraernus non-pinnate tentacles (t), the eavilies of whirh
eommunieate witli the general cavity (/), which is divided \ut*f
compartments by septa (m), on the walls of which tin- ironads (if) art-
developed. The axis is occupied by the stomach (>), which eum-
munieates below with the general cavity, and opens above Ity a mouth
marked by a special slit (od) ; p marks the point at which a chamlier
is in communication with its neighbour, and il is the lower surface of
the disk. The specimens and explanatory labels in Case XII In may
be found of assistance in understanding the structure of comls.

As it is impossible to preserve in alcohol the beauty of form and
colouring presented by Sea-Anemones, the aid of the artist lias been
called in, and sketches from life are shown on the walls.

As in the Zoantharia, there may be no spicules, a horny skelet<jn,
or a continuous calcareous skeleton ; Init spicules .scattered in the
flesh are not known.

Of the soft-bodied forms other than the well-known Sea-Anemone
of the shore, attention should be directed to the remarkable Ori-
anthiis memhi(ii>arr'i(>: (Fig. s\ which makes for itself a curious woven
tube, open at either end. The effect of this is that, during a
dredging operation, the Oeriant/ius generally succeeds in making his
escape, and a mere empty tube is all that rewai'ds the dredger.

The Antipatharia have a purely horny skeleton, which encl<»>es a
central canal and is always spiny. This skeleton may be a single
rod, as in Cirripathos, where it may attain a great height, or consist
of a collection of straigiit rods, as in the remarkable forms from
Mauritius, which has been called Antipat/ies rohillanU ; or it
may be more or less branched and form tufts or wide plates, sus in
A2)hanipathes, or the branches may fuse with one another, as in
Arachnopathes, an elegant example of which will be found l>y itself
on the wall near the middle doors. The most connnon form is the
tree-like .1. abies (Fig. I))-

According to the recent researches of Dr. Carlgren, the large
black coral-like structure which forms such a cnspicuous objwt
opposite the eastern door to this Oallery, and which is known as
Gerardia savaUa (Fig. 1<>), has been wrongly regard.d as an Anti-
patharian or horny coral. It is, according n» the Swedish naturalist,
allied by the structure of its polype to J'aruzoanlhiiK, and niust
therefore be placed with the otherwise soft-bodied Xoan(/i(tn<i. Tlu-
specimen here exhibited, wiili a suiiablr explanatory label, is sur-
prisingly large, and nothing like it is possessed byanvt.th.r Museum
of Natural History.

70 GUIDE TO THE CORAL GALLERY.

The majority of the specimens belong to the group of stony corals
or Madreporaria. The stoniness is clue to the secretion of carbonate
of lime by the skin of the lower part of the polyp. As the body
grows against this unyielding surface it has to give way, and forms
folds ; the skin of these folds again forms plates of carbonate of lime ;
and thus we get the outer " wall " and the inner septa. The extent
and proportion to which these are developed vary greatly, especially
in the colonial forms. In these the nutrition of the colony is effected
by a system of canals ; the appended figure (Fig. 11) is Dr. G-. H.
Fowler's representation of the canal system of Rhodopsammia. When,
as in the genus Madrepora and its allies, this system perforates the
substance of the coral (Fig. 12) the coral is said to be perforate.

The result of budding, long continued and extending layer over
layer, is the formation of large solid masses, which go to form coral
reefs ; the final fate of reef -corals is well indicated in Case G b, where
the specimens selected for the Museum by the late Mr. Darwin are
shown. The size to which colonial masses of coral may grow may
be judged from the two enormous specimens of TurUnaria peltata,
which cover an area 16 feet and IG feet 8 inches round, and weigh
12 cwt. and 13f cwt.^ respectively (Fig. 13). Sometimes a coral is
by the force of the waves carried away from its resting-place ; if it
be dead, and its substance filled with air, it may float ; if so, it will
become, like the large mass of Favia (Fig. 14) shown at the entrance
to the Shell Gallery, the sport of the waves, and may at last find its
home on an island, where the species to which it belongs is never
found in the living state.

Naturahsts experience great difficulty in determining pieces of
coral ; the reason for this is to be seen in the photographs of Tvr-
hinaria, where marked differences in appearance (Figs. 15, 1(>) are
easily apparent. The causes of these differences are seldom easy
to discover, and the guesses of stay-at-home naturalists are of little
service. It seems certain that maddiness of water may be an
important influence, as a deposit of sediment would kill the centre
of a cup-shaped coral ; here and there indeed there are indications of
spouts by which water may run ofl'. The extraordinary differences
seen in the large mass of " Brain coral," Maeandrina cerehriformis
(Fig. 17), which is placed in the adjoining corridor, are due, it is
suggested by one experienced in coral reefs, to a marked difference in
the amount of sunlight which could reach the two halves of the mass.

1 1 cwt. = 112 lbs. ; 60 kilograms is about equal to 1 cwt.

-Trt^

Vir.. 2.

Cl.AVl I.AUIA.

Fig. 3.

Al.CTONU'M.

Vu:. 4.

^^^yijfi

1 I lllli>llA

Fiu. 5.

Calligoh'Ha.

Fiti. tJ.

Skction or Ska-Animone.

Fig. 8.

s

■• *■»»"»

(■eKIANTIUs mi MIlUANACKrs

Fi<;. 9.

AMirATUi:.- Aiui..-

Fig. 10.

ni:i!AUI>lA SAV.M I.\.
(HiillK'ed III iiiii'-liri iilii III mil II fill nZi .)

Fig. U.

Khodopsammia.

Vu.. 12.

JlAUHEl'OllA.

«

3

5 4

Fig. 14.

1"avi.\.

I

Fir.. ]-,

TllllllNAKIA.

1

I

Vui IC.

TlJUUlNAItlA.

Fir, 17.

M VKASIUilNA ( KKl r.UlFoUMl-

Fi.;. 18.

I'lClliArnniVl I.I V MAMCINA

Fig. Jy.

Fl-AliKl-LUM IJiOKKbl.

Vu;. 20.

1)K8M0PHY1J.I'M INI. ENS.

Fig. 21.

Bathyactis Svmjietkic.\

377

C7B83

1907

British lluseuiu (Natural History)
Dept, of Zoology

Guide to the coral gallery

BioMed

PLEASE DO NOT REMOVE
CARDS OR SLIPS FROM THIS POCKET

UNIVERSITY OF TORONTO LIBRARY

J

ANTIIOZOA. 71

Full-gT(j\vii corals are not always liiitre masses; tla-y n • • ' uf
great delicacy and beauty, as is shown l»y Fig. 1h, \vhi< li ■ u

TridacophijlUa manidna, and by tbc three succeeding W h

represent various deep-sea corals, Case Xh. The discovery of life ut
great depths — depths as great as the heights of some of the highest
mountains of the world — was one of the most inten-stii ' '*

of the second half of the last century, and has led to a u'. ... ..,■ .. um;

in 3ur knowledge of the globe we inhabit.

( 72 )

INDEX.

Acantharia, 12.
Acinetaria, 14, 19.
Actinophiys, 4, 6.
Actinosphserium, 7.
Agalma, 61.
Aglaophenia, 47.
Alcyonaria, 67, 68.
Alcyonium, 67.
Araa?ba, 1.

AnteuBularia, 46, 52.
Authomedusffi, 43, 56.
Anthozoa, 67-71.
Antipatharia, 69.
Antij)atlies, 69.
Aphanipathes, 69.
Aphrocallistes, 29.
Arachnopathes, 69.
Asconidte, 25.
Astylus, 54, 56.
Athecata, 43.
Aulacantha, 14.
Aulosphsera, 14.
Aurelia, 58, 59.

Bath sponge, 35.
Bell-animalcule, 17, IS.
Beroe, 65.
Biloculina, 10.
Blood Coral, 54.
Blood parasites, 14k.
Boring sponges, 32.
Bougainvillea, 40, 41, 42, 43.

Calcarea, 23, 25.
Calcareous sponges, 23, 25.
Calligorgia, 68.
Campanularina, 45.
Caravella, 63.
Carchesium, 18.
Carmarina, 56, 57.
Carnosa, 25, 31.
Caulospongia, 32.
Ceratella, 45.
Ceratium, 16, 17.
Cercomonas, 15.
Cerianthus, 69.
Cestus, 65.
Chalinid sponges, 34.
Chitina, 45.
Chonelasma, 29.

Choristida, 30.
Ciliata, 14, 18.
Cirripathes, 69.
Chondrilla, 31.
Chondrosia, 31.
Clathrina, 23, 24, 25.
Clathruliua, 5, 7.
Clavatella, 42, 45.
Clavularia, 67.
Cliona, 32.
Coccidia, 14c.
Codosiga, 16.
Coenothecalia, 68.
Comb-jellies, 40, 64.
Commercial sponges, 36.
■Coral-like Hydrozoa, 40, 47
Corallistes, 30.
Cordylophora, 44.
Corticata, 14, 19.
Cotylorhiza, 59.
Covered-eyed Medusje, 55.
Craniella, 29.
Cryptohelia, 54.
Ctenophora, 40, 64.
Cycloclypeus, 9.
Cydonium, 30.

Dendrosoma, 19.
Demospongise, 25, 29.
Dictyonina, 29.
Dictyopodium, 13.
Didymium, 6.
Difflugia, 4.
Diphasia, 38
Diphyes, 61, 63.
Discomedusaa, 59.
Distichopora, 54.
Dorataspis, 13.

Echinonema, 32.
Esperiopsis, 32.
Eucyrtidium, 13.
Euplectella, 20, 26, 27.

Favia, 70.
Flagellata, 14, 15.
Fleshy sponges, 31.
Foraminifera, 3, 7.
Four-ray sponges, 29.

Fresh-water Polyp, 38.
Fresh-water sponges, 32.
Fuligo, 5.

Fungus animals, 4.
Funiculina, 68,

Geodia, 30, 31.

Geodiue sponges, 30.

Gerardia, 69.

Glass sponges, 24, 26, 27.

Globigerina, 9, 10.

Globigerina ooze, 10.

Gonium, 15, 16.

Gorgouella, 68.

Grantia, 26.

Gregarina, 14a.

Gymnoblastea - Antbome-

dusse, 43.
Gymuomyxa, 3.

Halichondria, 20, 21, 22, 23.
Haliclystus, 59.
Haliomma, 11.
Halisarca, 37.
Heliopora, 68.
Heliozoa, 3, 6.
Hexacoralla, 67,
Hexactinellida, 24, 26.
Hippospongia, 35, 36.
Hookerella, 68.
Hormiphora, 64, 65.
Horny sponges, 25, 34.
Hyalonema, 28, 29.
Hydra, 38, 39, 40.
Hydractinia, 43, 44, 47, 48.
Hydrallmania, 46.
Hydrocorallina3, 40, 47,
Hydroida, 40, 55.
Hydroid Zoophytes, 40.
Hydromedusse, 55, 56.
Hydrozoa, 38-66.

lanthella, 87.
Infusoria, 14.
Isis, 68.

Jelly-fish, 40.
Juncella, 68.

INDEX.

ir,

Kcratosa, 25, 34.

Lace sponge, 28.
Lagena, 9.
Lavcrania, 14e.
Leptomedusge, 5G.
Leucosolenia, 25.
Limnocnida, 56.
Limuocodium, 56.
Lithistid spouges, 30
Lobosa, 3, 4.
Lobster's Horn Goralliue,

46.
Lophocalyx, 2'J.
LucernariEB, 59.
Luffaria, 37.
Lyssacina, 26.

INIadrepora, 70.

Madreporauia, 69.

Maeandriua, 70.

Malaria, 14e.

Medusie, 38, 40, 43, 54.

Miliolina, 6.

Millepora, 38, 47, 49, 53,

54, 55, 56.
Mouaxouida, 23, 25, 32.
Mouaxou sponges, 25, 32,

33.
Monocaulus, 44, 49.
Monoxenia, 67.
Mycetozoa, 4, 5.
Myxospongida, 25, 37.
Myxosporidia, 14d.

Naked-eyed Medusae, 55.
Narcomedusaj, 56.
Nassellauia, 13.
Neptune's Cup, 32.
Neptune's Trumpet, 37.
Noctiluca, 17.
Nummulites, 9.

Obclia, 46, 50, 56.
Octocoralla, 67, 68.
Osteocella, 68.

Palythoa, 29.
Paudica, 56.
Paragorgia, 68.
Paramecium, 19.

I Parazoanthus, 69.

Parmula, 34.

Pelagia, 59.

Pennaria, 43.

Pcnnatula, 68.

Pennatulidae, 68.

Phseodaria, 14.

Phyllospongia, 37.
, Physalia, 62, 63.

l^hysopbora, 61, 63.

Pilcma, 59, 60.

Plumularina, 45.

Podded Coralline, 47.

Polystomella, 8.

Porifera, 20-37.

Porospora, 14.

Porpita, 63.

Poterion, 32.

Proterospongia, 16.

Proteus animalcule, 1, 2.

Protozoa, 1-19.

1 Quartan Ague, 14k.

Radiolaria, 3, 10, 11.

Radiolarian ooze, 10.
i Katbkea, 56.
i Renilla, 68.

Reticularia, 7.

Rbabdocalyptus, 28.

Rbapbidiopbrys, 7.

Rhegmatodes, 56.

Rhizopoda, 3, 7.

Rbodalia, 63.

Rbodopsammia, 70.

Rotalia, 9.

Sleeping Sickness, 14g.

Spicules, 27, 28, 30, 33.

Spouges, 20-37.

Spongia, 34, 35, 36.

Spongilla, 34.

Spongosphiera, 12.

Sporozoa, 14.

Spumellaria, 11.

Squirrel's Tail Zuophyto,
46.

Stag's Horn Millepora, 49.

Stentor, 18.

Stylaster, 38, 53.
' Stylasteridiu, 47, 53.
I Stylonychia, 19.

Subcritcs, 32.

Sun-animalcule, 4, 5, 6.

Sycon, 23, 25.

Tertian Ague, 14k.
Tetracoralla, 67.
Tetractinellida, 25, 29.
Texas Fever, 14.
Tiara, 56.

Thecapbora, 43, 45.
Thuiaria, 46.
Toilet sponge, 35.
Tracbomeduste, 56.
Tridacopbyllia, 71.
Trumpet Polypus, 18.
Trypanosoma, 14g.
Tsetse Disease, 14u.
Tubipora, 67.
Tubularia, 43.
Turbinaria, 70.
Turkey sponge, 34.

Salpingoeca, 10.
■ Sarcosporidia, 14d.
' Scypbomedusai, 55, 59.

Sea Beard, 46.

Sea-Kidney, 31.

Sea-Nettles, 54.

Sempcrella, 28.

Scrtularia, 38, 43, 46, 51.

Scrtularina, 45.

Sickle Coralline, 46.

Silicea, 24.

Silk-worm Disease, 14.

Simplest animals, 1.

Sipbouopbora, 40, 56, GO, Xipbacautba, 12.
61.

Six-ray sponges, 24, 26. I Zoantharia, 67, 69

Umbellula, 68.

Velella, 63.

Ventriculites, 29.

Venus' Flower-Basket, 20.

26.
Venus' Girdle, 65.
Volvox, 15, 16.
I Vorticella, 17, IS.

I Waltoria, 28.

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