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JOURNAL
MARINE ZOOLOGY
MICROSCOPY.

A platinly-worded Biological Magazine.

EDITED BY
JAMES HORNELL,
Director of the Fevsey Marie Biological Station.

VOEUMES Tc 11.

JERSEY:
ieEI ts jis VaViAK TNE BIOROEICAL S LADION:

Lonpon: ELuiot STOCK.

1893-1897.

CORRECTIONS.

Vou. I.

On page 18, line 6, read ‘‘ ovary” instead of ‘‘ ovum.”

In the article on “ Variation in the Operculum of Serpula,” pp. 57-60, delete
all paragraph ‘“‘C” on p. 60, also the whole of the last five paragraphs of the
article from the words “‘so much for collateral evidence,” etc. This is necessary
as the dorsal processes, or ‘‘ tentacles’ of Sabella, are now known to be processes of
the collar, and thus not homologous with the operculum of Serpula.

Vot. II.

In the explanation of Plate V., for ‘Figs. A to D, Plumularia pumila,” read
“ Bigs. A to D, Sertularia pumila.”

Page 24. Note that the Pteropoda are now definitely merged with the
Gastropoda and do not constitute a separate class.

Page 80. Let the 16th line from the bottom read “asserts that it will be only
the effects of hatcheries such as this, that can prevent.”

: , L
\4 Ea ar ynteg pw

CONTENTS.

PAGE
INTRODUCTORY - - - - - - - - - - 1
JERSEY BIOLOGICAL STATION ~ - - - - EGP), 153) lilo all
Notes on ANIMAL COLOURATION :—

1. LATERAL INDEPENDENCE IN THE Nervous CONTROL OF
CoLOURATION IN THE OcToPpuUS. - - - - - 3
2. AN ALBINO LopsTER-~ - - - - ee ea - 4
3. ALBINISM AMONG Marine ANIMALS - - - - 6
4, THE CoOLOURATION OF SPONGES - - - - - i
5. Taz Conour Scaur in Marine ANIMALS - - 5 Oe
6. Tot PROTECTIVE CoLORATION OF HIPPOLYTE VARIANS ii., LOL
Tur Hapits oF THE OCTOPUS IN CAPTIVITY - - - - 9
THe Hunting Crart oF THE JOHN Dory - - - - 12
On THE METHOD oF DISPERSION AND FERTILISATION OF OVA IN
SOME SABELLIDS’~ - - - - - - - Be wells)
THE REARING OF STAR-FISHES IN CONFINEMENT - - - 25
THE CLEANSING OF THE LITTORAL BY THE LUG-WORM - Seoul
On THE LocomMoTION oF THE Mounuusca - - - - = ail
CONTRIBUTIONS TO THE STUDY OF VARIATION :—
. 1. Sexuan Contour DIvERGENCE IN Lasrus MixtTUus - =O)
2. VARIATION IN THE OPERCULUM OF SERPULA - - = Sth
3. ABNORMALITIES IN THE MuscunaR Banps oF SALPA - 955
4. On a CANCER PAGURUS WITH SUPERNUMERARY CHELZ il., 99
THe Lire-History oF THE Rock BARNACLE - - Sptcll o stl. J
THE DESCENT OF THE OCTOPODA - - - - - 87
On InREGULAR GROWTH OF THE SHELL OF THE LimpeT - _ ii., 7
CONTRIBUTION TO THE ZONING OF THE SHOKE - - - ie, 9)
SPIRULA PERONII - - - - - - - - i, 23
FAUNA OF THE CHANNEL ISLANDS :—
1. REPORT ON THE SCHIZOPODA, CUMACE, ISOPODA, AND

AMPHIPODA - = - - e = = u., 49

2. REPORT ON THE FREE-SWIMMING COPEPODA - - i., 95
THe Usre or FoRMALIN AS A PRESERVATIVE FLUID - = Whos 18)
On SuRFACE TENSION AS AN AID TO LOCOMOTION AMONG MARINE

ANIMALS - - sasha - - - - - li., 59
THE PERMANENCE OF THE SCYPHISTOMA STAGE OF AURELIA- Tiles (ONL

Tue PossIBILiTies oF FISHERY IMPROVEMENT IN JERSEY, WITH
NOTES ON THE PRESENT STATE OF MARINE PISCICULTURE,
ETC. - - - - - - - - - io 33
THE PRoTECTIVE DEVICES OF THE GENUS HIPPOLYTE - ice JKOML

li CONTENTS.

MicroscopicaL StupIES IN Marine ZooLocy :—
1. Haurcrystus (LUCERNARIA) OCTORADIATUS
2. Tor ANATOMY OF TOMOPTERIS - -
3. THE ANATOMY AND LiFE-HISTORY OF SALPA
4, Sponces, AN INTRODUCTORY SKETCH -

5. A ContTRIBUTION TO OUR KNOWLEDGE OF THE COPEPOD,

MonstRinLA ANGLICA - - - -

6. THe Marin Facts CONCERNING AMPHIOXUS
7. THE METAMORPHOSES OF SQUILLA - -
8. THE PHytiosoma LARVA OF SCYLLARUS -
9. Tor STRUCTURE OF ANEMONES - -
10. Typican ALCYONARIA - - - -
11. Lirk-cycLe oF OBELIA GENICULATA -

12. On PoLYNOE PROPINQUA AS TYPICAL OF THE HIGHER

ANNELIDS) - = = = - -
13. Tar Taprote LARVa& or ASCIDIANS -

14. SPHAEROZOUM PUNCTATUM, A COLONIAL RADIOLARIAN
15. THe Hypror STAGE oF OBELIA GENICULATA

16. THE StanKkeD Larva oF ANTEDON -
17. CRESEIS, A TYPICAL PTEROPOD~ - -
18. THE CoryYNIDEA - - = - -
19. On SERTULARIA PUMILA
20. THE CIRRIPEDIA - 2 = 4 2

21. THE PLUMULARIDE - - - -
22. THE Eaas anp YouNG OF CEPHALOPODS
23. THE VisuaL ORGANS oF THE Mornbusca
24. Typicat British Bryozoa
25. THE SAPPHIRINIDZ - - - -
Boox Norticss - - - -

= 104
ii., 12
ii., 16
ii., 16
ii., 19
ii., 34
ii., 39
ii., 41
ii., 63
ii., 64
ii., 66

ii., 104

ii HO

- 30; 80; 92; ii., 33; iL, 48

The Journal of ¥ lavine wool oon
: and J Microscopy :

A PLAINLY WORDED BIOLOGICAL QUARTERLY.

You. I. No. 1. NOVEMBER, 1893.

INTRODUCTORY.

W* scarce know whether or not apology is due for the appearance

of this Journal in the long catalogue of Zoological periodicals.
However, we believe a few words of explanation as to the inception
of this project will suffice to justify its existence, and to arouse, we
trust, sympathy with the undertaking.

When the idea first arose, 1t was in the narrow form of the i issue
of several pages of letter-press, descriptive of certain microscopical
preparations of rare and interesting marine animals which were to
be issued from the laboratory of the Jersey Biological Station from
time to time. Gradually with further consideration the idea ex-
panded, and we now ask for your support on the plea that this will
be a journal wherein will be recorded. general life- history notes,
for the most part original, wpon the Fauna of British Seas,
together with descriptive articles and drawings of noteworthy points
in the anatomy and histology of the animals from which the above-
mentioned microscopic preparations are made. The greatest care
will be taken to insure accuracy in the drawings. Being original
these will have great value, not only to the amateur but also to the
professed specialist. Not their least recommendation will lie their
being coloured by hand from the living animals.

Notes on current Zoological literature and progress will appear,
while the microscopical portion will contain corresponding notes and
hints upon the preparation of objects for the microscope. These
subjects are in the present issue unavoidably crowded out, but this
will be remedied in the future. We shall, we trust, substantially
increase the bulk of the journal in succeeding numbers, but of
course this will depend directly upeo what amount of Sueront
naturalists accord ‘US,

2 ~ JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

Every effort will be made to render the matter in good and
lucid English. Technical terms will be avoided wherever great
sacrifice of directness is not involved. All articles will be relevant
and our efforts will be directed towards conciseness. The journal
will be the organ of the Jersey Marine Biological Station, and will
chronicle its progress, its struggles, and its encouragements, and thus
afford to its many friends and supporters interesting record of the
help it is rendering in a modest way to the cause of Natural Science.

The great majority of the present notes are furnished by the
Station, and unfortunately the Editor and his pen are responsible
for the whole of the present matter. Time has been too short to
obtain for this issue any literary assistance from friends, but the
Editor is able to promise that short notes will in future appear from
several able writers in the world of science.

A first number is always beset by certain grave difficulties that
however usually lessen with each succeeding issue. We are ex-
periencing this in a great degree, and plead this as excuse for
whatever blemishes disfigure the present pages.

But enough. Having asked your kind forbearance we must
push off and venture out among the waves of criticism with what
strength and courage and skill we can summon—

‘Tt may be that the gulfs will wash us down,
‘‘Tt may be we shall touch the Happy Isles,”

and whichever fate awaits us, we shall strive stoutly to deserve the
more fortunate.

Tue Jersey Bronocican Station. The hopes regarding the advantages that.
would accrue to Marine Zoological Science from the establishment of this Station, have
been shown, by the past nine months’ experience, to be well founded. Completed
in March of the present year, work was immediately begun in the stocking of
the aquarium tanks, and in the bringing together of representative specimens of the
local Fauna. Much remains to be done, but there can be no doubt as to the
suitability of the site chosen, and of the planning of the building.

In front, stretch for miles, immense areas of perhaps the finest collecting
ground in Britain; the Station boats are moored within a stone’s throw ; high tide
comes practically to the doors; the sea is pure and uncontaminated by sewage.
The land surroundings are equally good, being the prettiest and quietest suburb of
St. Helier; thus while having all the advantages of proximity to a large town,
the Station is free from the close atmosphere and traffic noises of an urban situation.

The building consists of three floors: The first answers the purposes of an
aquarium, while adjoining is a rough dissecting room, &c. The second contains the
type museum and reference library, and serves admirably as a demonstration
room. Finally upon the third floor, are partitioned compartments of ample size,
for the use of students and research workers ; several haye already taken advantage
of these facilities, and indications are that from next Haster onwards, there will
be quite a numerous band of students and investigators at work,

NOTES ON ANIMAL COLOURATION, .

(Series af)

BY JAMES HORNELL.

I. On LATERAL INDEPENDENCE IN THE NERVOUS CONTROL OF
COLOURATION IN THE OCTOPUS.

(YELDOM have I been more surprised than when I first saw

parti-colouration in the Octopus. I had been watching one of
these creatures creeping slowly from point to point over the rock-
work of the large tank which it inhabited in company with four
others of its kin. In colour it was of the same dappled brown
characteristic of the others. But suddenly, without apparent cause,
the colour of the right side of the body as, too, that of the four
arms appertaining to that- side, paled almost to snowy whiteness.
- The division into coloured and uncoloured halves was absolute: had
the median line been drawn with mathematical accuracy down the
dorsal aspect, the division could not have been truer. This curious
appearance lasted close upon five minutes, and though I took every
opportunity of watching for its recurrence, nearly a week passed
before I was successful. In this second instance it was not the same
individual and the side that became deprived of colour was the left.
The distinctness of the bipartite colouring was fully as well marked.
Since then I have found by close observation that while by no
means frequent, still this colour control was possessed by all the five
specimens under observation.

Complete functional independence so clearly marked as this, is
extremely unusual and it does not appear to have been noticed as
voluntarily practised by the animal in question. It has however
been observed as induced by artificial means during investigation
by Klemensievicz* on the nerve centres controlling the pigment
bodies or chromatophores of the Cephalopoda. These bodies—sacs
full of pigment—are each provided with a radiating set of muscular
fibres, which being excited, contract pulling the pigment sac into a

* “ Beitrige Zur Kenntniss des Farbenwechsels der Cephalopoden,” Sitzungsber
der Acad. Wien, 1873,

4. JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

stellate form of much greater size that in the resting condition.
When exciting cause is gone, the muscles relax and the pigment
sac springs back to its normal spherical contracted state. What
Klemensievicz found was that the innervation or nerve supply of
these muscular fibres had its centres in the two peduncles or stalks
of the optic ganglia, that issue, one on either side, from the coalesced
ganglia functioning as the animal's brain... Moreover he discovered
that irritation of one of these centres caused immediate change of
colour in the corresponding side of the body. This implies a very
close connection between the sense of sight and the chromatophores
of the skin. Frequently have I seen an Octopus crawling among
brown Fucus of a tint absolutely similar; anon as he darted away
from this hiding place among the weed, he paled and grew grey
as the sand over which ‘the course lay. From what we know, the
alteration of colour would here be a reflex result working through
a visual perception of the alteration in the surroundings, passed
inwards to the centre having control of the pigment sacs.* I believe”
the action to be purely involuntary, the adaptation being a process
too complicated and delicately precise to be coordinated consciously.

In the same way the deep uniform chestnut-brown assumed
by the animal under the excitement of combat—which I have
frequently seen—is a reflex effect of the general nervous excitement
aroused in the whole system; muscular contraction and not relaxation
being well known to be one of the chief constant characteristics of
strong emotion of this kind.

Again in swimming, more than usual effort is put forth by the
Octopus—and this action characterised thus by vigorous muscular
contraction is performed by the animal always in a colour guise of
rich deep brown. When resting—which takes place usually during
daylight—the colour is generally pale. Illness too is accompanied
by great lack of colour. 3

In connection with the phenomenon of parti-colouration, it is
interesting to note the following somewhat. related instances. In
Guernsey Museum is a lobster coloured of a pale pink down one side,
but of the ordinary deep blue black upon the other. No special
dissection was made, but there is obvious reason to believe the cause

* Since writing the above, it occurs to me that an alternative explanation can be given
by supposing that the chromatophores act as eye-spots; that they themselves receive the
impression of change in the colour surroundings, pass it back by their nerves to the con-
trolling centres, which, upon this irritation, give out impulses bringing about alteration in
the form of the chromatophores, and conséquent change in the body hue. But I doubt
this, principally because one would rather expect local colour change, than suffusion over
the whole body as does normally happen. We would expect the alteration to occur only
on that aspect turned towards the coloured objects of the environment, and this is not

what does happen. To settle this point, I purpose carrying out some direct experiments,
the results of which will be duly recorded,

NOTES ON ANIMAL COLOURATION. | 5

Was an injury to the nerves controlling the nutrition of the pigment
cells upon one side of the body, as there remain signs of an old
wound penetrating a little to one side of the median line right
through the body. )

The other case is one quoted by Dr. Lawrence Hamilton in
“ Natural Science” for Sept., 1898, to the effect that the Chameleon
has been observed to be red on one side while of a green hue upon
the other. The explanation has been hazarded that one side of the
animal was asleep while the other was awake !

II. An AtLpino LOBSTER.

Before me as I write is a very unusual case of abnormal
colouration, in the form of an all but white Lobster. Six weeks
ago some fishermen brought it m, in good health. They told with
much exultation how pleased they had been to find so curious a
beast in one of their pots set in St. Aubin’s Bay, on the south coast
of Jersey. Never before had they taken or heard of such a curiosity,
and experience and enquiry bear out the rare occurrence of such
colouration, or rather want of colouration.

In size, this strange Lobster is fully adult, 14 inches long from
rostrum to telson. When living in one of the large Aquarium tanks
along with normal deep blue-black kindred, the contrast was wonder-
fully well marked. The one in question gave a definite impression
of white, albeit rather soiled. Close and minute inspection showed
this soiled appearance to be due to a very faint development of
bluish pigment. On the carapace and limbs it was a pale and
diffused hue that in no way could be said to mask the limy whiteness
of the shell. On the abdominal parts the hue was somewhat better
marked, the pigment blotches showing faintly but still traceably.

With its companions, it held its own. Appetite was good and
apparently it was in perfect health, Whatever the cause of the
colour may be, one fact was self-evident, its light hue rendered it
extremely conspicuous. When its dark blue relatives were at rest
in their nooks of retreat, they were difficult to discern. Their colour
was not out of harmony with their surroundings, but nia white one
was so, most markedly.

If not pathological, this paleness of colouring is probably an
instance of partial reversion in hue to that of some lighter coloured
ancestor of different habit. The blue-black colour of normal Lobsters
is certainly acquired. No other British crustacean boasts the same
hue. Reds and browns predominate among the larger, while among
the smaller Decapods, absence of pigment is very general. The
swimming prawns (Palwmon) for instance, are marked by a nearly

6 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

complete want of colour and by an allied transparency. The burrow-
ing prawns (Callianassa, Gebia and Agius) on the other hand,
are characterised by porcelain-like shell armour, ‘either of pearly
whiteness or else of coral pink.

III. ALBINISM AMONG MARINE ANIMALS.

From the preceding note, the transition is natural to a con-
sideration of albinism generally among the inhabitants of the sea.

At the outset we may well consider the characteristics of
albinism among land vertebrates. There the phenomenon is seldom
found among the Reptilia. It is among the divisions possessing
feathery and hairy epidermal clothing (Aves and Mammalia) that
it is met with most frequently. Lack of colourimg matter in such
cases, means albinism of snowy whiteness of plumage or pelt, 1e.,
opaque whiteness. As every one now knows, when such is not an
abnormal feature but is the settled hue during life or is regularly
recurrent at one season, the possessing animals are, in a great
majority of cases, inhabitants of snow-bound regions—polar or else
above the snow-line in our great mountain ranges.

Albinism here may be assumed either as a method of protection
or as a device to allow of unobserved stalking by carnivorous animals.

In the sea albinism in this narrow sense of opaque whiteness is
seldom met with. There are no snowy plains beneath the waves—
indeed in the dim light that reigns in the shallows and in moderate
depths, whiteness would be a positive and very dangerous attribute.
To the weak and ill-armed it would mean speedy extermination—
so where it is present, either its employment will fall into the
category of (a) warning devices, (b) lure devices to attract prey,
or lastly (¢) where the possessor has neither use nor fear for any
particular colour. ‘

It may here be convenient to place in tabular form the more
common albino representatives yielded in British Seas by the various,
animal classes. |
Protozoa :—Foraminifera, eg., the porcelain-white tests of Mili-

olina, &c. (calcareous).
SPONGIDA :—a. The aspiculous Halisarca sometimes.

b. The calcareous sponges generally, eg.. Leucandra
nivea, Ascaltis, Sycandra ciliata, S. compressa
and often Ascetta (Leucosolenia) coriacea.

CNIDARIA :—Actinoloba dianthus ; Alcyonium digitatum.
VERMES :—Turbellaria, several.
Polycheta, Nephthys (burrowing), and the white plumes
of a certain Sabella.

NOTES ON ANIMAL COLOURATION. : 7

MoLLusca :-—Pholas, Lima, Cardiwm, Teredo, and others, mostly
burrowing.

Seericn: :—The burrowing crabs Corystes and Thia, also the
burrowing prawns Callianassa oe. and Gebsa
and Agius (pinkish).

ECHINODERMS :—Oucumaria (hiding). °
Ophiura albida (calcareous).

TuniIcaTA :—Circinaliwm concrescens (calcareous spicules).

FisHEs :—Under surfaces of Flat fishes—Plaice, Turbot, Soles; also

of Ray fish and their relatives.-

In our present obscure acquaintance with colour significance, it
behoves us to proceed with caution in our speculations. Still two
striking facts come out in perusal of the foregoing list; first, that
white is associated in most cases with either the presence of a
calcareous skeleton (Forams, Sponges, &c.), or with the habit of
burrowing. In the latter case it does not seem to be the absence
of ight that prevents the development of colour—there are abundant
instances of deep pigmentation developed in the dark. Cases in
point are the burrowing purple Spatangus, the dark-green lug-worm
(Arenicola), pigmentation of the nerve system of Anvphiowus, of the
mesentery of the Frog, &.

Animal colouration has, I believe, always direct value to the
possessor and is a developed attribute, being kept in esse solely
by the continuation of the original exciting cause or causes. The
principal of these are protection, warning, luring, sexuality and food
supply. Take the exciting factor away and gradually the colouring
having lost its usefulness will disappear. The production of colour
must mean expenditure of energy ; an allowable expenditure so long
as it serves a useful purpose, but which becomes waste when it
ceases to do so—a waste which natural selection is bound to dispense
with in time. What does this lead to? Clearly that it is probable
that the burrowing forms that are albino (worms, crustaceans,
molluscs, &c.) may have dispensed with a former colouring because
of a present non-requirement of such. The same explanation, I
believe, applies to the under or white side of flat-fishes.

IV. THE COLOURATION OF SPONGES.

In the list given above of albino animals, the long list of white
caleareous sponges is remarkable—no other order of animals is so
consistently uniform in colour. The explanation I have to offer is
' that this is due (a) to the spongin or ground tissue of the sponge
being reduced to a minimum, and (b) to the shape of the spicules
being such that the optical effect produced by a dense closely packed

8 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

mass of them is snowy white to the eye. Corroboration.is furnished
by the occasional occurrence of two exceptions in colouring, viz., in
Ascetta coriacea and in Aleyonium digitatum. In the former case
the sponge frequently varies from the normal white to a lemon yellow
or orange, and even red, while in some rare cases Aleyoniwm is found
of an orange hue. Examination microscopically, shows in both cases
the new colour to lie in the ground tissue. Again, if we boil a piece
of caleareous sponge in potash solution and get rid thus of all the
animal matter, leaving spicules alone—the latter will be found to
compose a snowy powder at the bottom of the vessel.

It is interesting to note that in marine animals, next to the
primary white, comes yellow in various shades, grading’ easily into
orange and then into red; an interesting fact when we remember
that a similar colour series is made out in the acquisition of colour
by flowers.

Another interesting point brought out by comparative exam-
ination of sponge colouring is that species with siliceous skeleton
spicules are well advanced in the colour. scale. Scarcely any have
the primitive white. ae |

How is this? It is not im all cases that siliceous spicules have
such differences in form from the spicules of calcareous sponges as
to lose the optical appearance of whiteness, because to take Pachy-
matisma as an example—even a small mass of its separated spicules
appears of snowy whiteness, and yet alive, the sponge is not so
coloured. The difference is certainly due in this case, to the optical
whiteness of the spicules bemg masked by a superior development
of coloured fleshy: tissue. The other siliceous sponges have also this
superior development of soft tissue, and this appears to have become
pigmented through the action of certain of the following factors :—
(a) a necessity for some colouring other than a dull greyness to act
as a “ warning” colour to predatory animals, (b) the greater ease in
producing other pigments than white, or (c) the greater utility for
this purpose of such alternative colours. The former of the two
last mentioned is most certainly the more probable, for the white
calcareous sponges are quite as immune from attack as any of the
gorgeous scarlets and oranges of the siliceous division. What holds
good of these sponges applies equally to the crusting compound
Ascidians, which in brightness of colour rival, and at times outstrip
.the sponges.

OBSERVATIONS ON THE TABITS OF 1
ANIMATS.

BY JAMES HORNELL,

Series L—a. The Octopus in captivity (cleaning of Suckers,
strength and feeding habits).
b. Hunting-craft of the John Dory.

J. Tue Octopus IN CAPTIVITY.

ERHAPS of no other animal have more fabulous travellers’
tales been recounted than of this creature. Some have sought
to identify it with the terrible Kraken—that superlative sea-terror
of our viking ancestors. Others have figured it as the bona-fide
sea-serpent, and then who is not:familiar with the wonderful cuts
in the old natural history books of the-“ colossal polypus” seizing
a great three-masted ship and dragging it down to the depths.
In more recent years, Victor Hugo has, with poet’s license,
painted in sensationally gruesome detail, such an exaggerated and
terrifying picture of the Octopus, that the true details of its really
_grim quaintness are apt to fall flat and appear trivial to those
whose knowledge extends no further than the “ Toilers of the Sea.”
| Quaint creatures indeed! Five of them are now restlessly
’ erawling, swimming and climbing about the rockwork of a tank
close at hand as I write. There, see the large fellow in the centre
perched monkey-like on a boulder—what is his object in making
an animated ‘catherine wheel’ of himself as he is domg? .See how
the plant arms writhe and coil, in and out, over and under, inter-
mingled, and upon themselves in supple twists and turns, as of a
heap of lampreys in a bowl. See now the motion slackens and
slowly the animal reverts to his sly slowly moving normal state.
Frequently have I seen this performance, and it always appeared
to give considerable satisfaction to the animal.

‘For a little while I was puzzled to account for such acrobatic
movements, but soon I began to notice that these were accompanied
’ by a throwing off of many disc-shaped cast-skins of suckers. The
inference became plain that the process was a cleansing one,

10 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

intended to get rid of this loose skin. After a period of activity,
especially after a rough and tumble scramble for food, many suckers
are seen with shreds of loose skin partly detached. As pneumatic
organs the suckers must thus be much impared—hence the necessity
for a frequent “rub-down,’ which is performed in the manner
described. : a aks

STRENGTH. The strength and carrying power of the Octopus
is—legends put on one side—really wonderful. When we had ours
first, we planned out a picturesque arrangement of loose boulders
to ornament the tank, but alas for earthly hopes and scenic display,
our Octopus had their own ideas of how a tank should be arranged,
and—we had three at first—piled the stones in ugly inartistic heaps
In three corners. The route each boulder had taken was plainly
graved by a deep rut in the loose sand and shingle that covered
the bottom. -Some of the blocks of -stone were fully 9-in. in~
diameter, and our smallest Octopus—3-ft. 6-in. spread from tip to tip
—could easily move them about lke so many play things. Time
after time this was done, to the woeful stirring up of all the sediment
that in-even a short space of time gathers ina tank. Indeed at last
we were compelled to take away the sand and shingle, in which our
friends had been so fond of blowing out nest-like lairs, and for
sanitary reasons to leave them with but a few very large boulders
and the thinnest layer of shingle in the bottom.

The overflow pipe in this tank is moveable and fits at its lower
-end into the opening of the low-level outlet. Being of lead, the —
weight of this pipe is considerable—to give the exact figures 9-Ibs.
12-ozs. We are accustomed to lift it out bodily when desirous
of emptying the tank completely. . We never dreamed of such
being liable to be moved by any force but our own, so our surprise
may be judged when upon going down early one morning, we found
the Octopus tank dried up; the overflow pipe wrenched out and
lying prone on the bottom. Our concern was great and well founded
—all the inhabitants were apparently dead, but the faintest play
of colour in some argued a spark of life remaining. As quickly
as possible we transferred the three that showed this to water,
and soon had the satisfaction of seeing them recover. Two however
we laid regretfully out on the floor, deploring their untimely demise
—but to our unexpected pleasure one gave out a faint movement
just sufficient to arouse hope—so we transferred both to the water
with the other three, and were rewarded beyond our utmost hopes in
soon seeing them make languid motion. The lapse of 24 hours
saw them again in their usual healthy condition, but we had had
our lesson. Ever since, we take care to wedge the overflow pipe
firmly down before leaving at night.

ne HABITS OF MARINE ANIMALS. 11

We have also to take care to close the shutter securely above
the tank, for twice we have found, after-a short absence, one of
‘the Octopus crawling excitedly about the floor like some monstrous
spider. :
Usually they are fed upon the common green Shore Crab
(Carcinus), three or four daily—but they are far from being
fastidious. If a few limpets be thrown in, they dart from their
lairs and pounce upon them in a way which seems very like the
_ turning of a somersault. Cockles, mussels, whelks—all are welcome
and quickly devoured. As a rule the detritus of shells is thrown
away within a couple of hours or less. In the case of Crabs,
the carapace and endophragmal system are picked beautifully clean
and are quite unbroken—the limbs too are separated and usually
broken at the principal joints.
Limpets are the most badly cleaned, as there is generally a
ragged ring of torn membrane left half-way up the inner surface of
the shell. . |
Apparently any moving object—barring fish—is seized and
tested for food. Several times I have thrown white pebbles in and
in all cases, when hungry, the animals have darted out and drawn
them to the mouth. It may be that this habit is not a natural
one but is induced by the method of feeding by throwing the food
into the tank—but whether or not this be so, I have little doubt
that it is by sight and not by scent that the Octopus hunts.
The Octopus usually, but not invariably, darts out upon the
prey. Often enough, if the object—say a crab—run within reach,
the Octopus leisurely casts out one of its long arms—as a rod-
fisher does his line--and lets the delicate tip touch lightly the
carapace of the prey. Lightly it touches, but none the less securely
is the crab caught. Some of the suckers have come into play.
Often a second arm is then thrown out and some of the terminal —
sucking discs of this attached. Then the animal is slowly drawn
to the mouth to be devoured at leisure, and strangely enough, the
Crab almost invariably makes not the slightest resistance. It is as-
_ though stupefied and rendered helpless by terror—or is it that it
feels powerless to resist ? Once one of the Crabs thrown in, did elect
to resist. It snapped viciously at the delicate arms, and surprised,
the Octopus cowered down, letting go its hold. Instantly the Crab
scurried away to climb up the tank side as far as possible out of
reach of the foe. Several times in the course of succeeding days

one or other of the Octopus tried to snare it, but with similar result
as the Crab always made a stout resistance. At last one day it
was mastered and we have never since seen a similar instance of
fight on the part of Crabs.

12 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

Il. Hunting Crarr oF THE JOHN Dory.

How like a consciously wise old vestryman is the Dory (Zeus
fuber) as he turns his great rotund solemn eye to survey the scene
around him, and erects his great dorsal fin, with its few long rays so
like the cherised and sparse hairs that ornament the afore-mentioned
gentleman’s polished bald cranium. A solemn and wise fish he looks,
aye, but there is crafé concealed beneath those smooth benevolent
pecksniffian features. See, he moves stealthily along to within four
inches of that Goby there on the bottom. See, with head directed
downwards and just sufficient gentle, almost imperceptible motion
of the fins to keep him in unchanged position, does he not
seem bent upon hypnotising the Goby? But there, the latter is
tired of being looked at. The Dory follows round to face him again,
but does not try to diminish the distance. Thus 15 to 20 minutes —
go. by, with alternate moves on the part of the two fishes, but
with no alteration in the distance. At last any vague fears that
the Goby had of his strange observer are lulled and he relaxes his
vigilance. The Dory now sees his opportunity; the colour bands
on his sides intensify and darken, the dorsal fin goes up—it had lain
folded down till now. This martial bearing takes but a moment to
put on—indeed it is really coincident with a lightning swift forward —
movement—a swift dash—a great telescopic mouth thrown out—
the disappearance of the Goby and a satisfied gulping on the part
of the Dory.

Thus it happened continually. Always a long stealthy stolid
staring stalk, often unsuccessful it is true, but still giving a very
satisfactory average, so the Dory appears to think. No doubt he
counts upon occasional failure. He knows and appreciates his own
large stock of patience, and is conscious that he can depend upon
it for a comfortable competence in life. Gobies, Smelts, Wrasses
and Grey Mullets have been fed upon in our tanks by the Dory. —

.Once recently the smaller of the two Dorys that we have,
“negotiated” a 15-spined stickleback (G@asterosteus spinachia)
quite 5 inches long. For a few seconds, the captor did his best
to calm within his capacious stomach the flutterings of the 15-spined
dorsal fin of the prey, but it was beyond his power. With sudden
determination the Jonah was shot out, and like his great forerunner,
seemed not one penny the worse. Away he swam after a moment’s
flurried hesitancy. There was a very obvious movement, what in
_ a higher animal might be termed a shaking of himself together,

and then a rapid return to every day humdrum existence.

The John Dory, we may add, lives very well in confinement.
Our two we have had a long time. ‘They are as can be seen

from the above, very particular about having living food, but so
long as it be small fish they do not mind what species.

~

~

ON ae METHOD OF DISPERSION

AND
; PERTILIZ ATION OF OVA IN SOME SABELLIDS.

BY JAMES HORNELL.

PRINCIPAL among the tube building Sabellids that live in
the Aquarium tanks at our Jersey Station, are a considerable
number of the fine Branchiomma (Sabella) vesiculosa, so remark-
able for well-developed eyespots at the tips of the filaments. This
species, one of the commonest on these shores, builds a tube some
7 to 9 inches long in the Zostera banks, with the upper opening on a
level with the surface, differing thus very markedly from the free
or projecting tube-form of the allied Sabella pavonia.

“Towards midsummer, dissection showed the genital products
well advanced towards maturity, so seeing that this Sabellid does
not depart from the usual characteristic of the Polycheetes in having
the sexes separate, | was induced to watch very carefully for the
time when fertilization should take place. It is worthy of preli-
minary note that under natural conditions, the tubes are seldom
_ closely set—usually they are from two to six inches apart. The
plumes too have a very short radius and never make a broad far-
reaching fan-circlet as in S. pavonia. When on July 5th the
sexual elements appeared, the sight was most curious and worthy
of the long and constant watch. First, a female Branchiomma.
was noticed passing up into the circlet of filaments, from—I believe—-
the median gutter that runs along the ventral side of the body, rather
numerous large white ova. These gradually accumulated for some
time in the cone-shaped hollow formed by the filaments; then
rather suddenly the animal retracted its plumes with considerable
force, such indeed that the ova by the impetus imparted were
shot upwards and outwards to a distance of several inches. <A
minute’s rest or less, saw the animal again with fully expanded
plumes, passing up ova again from below in rapid succession. Then
when the filaments were once more clogged, a similar sudden jerk
dispersed them widely; so the process went on for nearly three-

14 - JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

quarters of an hour with more or less regularity—in fact until
all the ova had been passed out. By this means the ova instead
of accumulating in a heap around the opening of the tube were
spread as a thin layer over quite a large circular area—not less
than 10 inches across, in still water.

Very shortly after the beginning of the operation, a 1 neigh-
bourmg individual began to manifest signs of a certain unusual
excitement, and in a few minutes, from the centre of its filaments,
there arose a thin greyish cloud, in appearance and form like smoke
wreaths curling lazily upwards from some sleepy hamlet on\a breath-
less summer afternoon. A'male it was that had become aware of
the call that was bemg made, and the cloud that was rising slowly
was composed of a multitude of. spermatozoa that were being ejected.
Unlike the female, the dispersion was not aided by any sudden
retraction, the reason being that on account of the minute size of
the sperm elements they floated quite a considerable distance (6 to
7 inches) in even the calm water of an Aquarium, before settling to
the bottom and there meeting and fertilizing the ova that had been
ejected just prior. These two had not been busy for long when one ~
after another the other individuals in the tank took up the tale in
the same manner, and before the day was done all had finished.
Apparently, in these animals, to avoid undue waste; the genital
products are ripened nearly simultaneously, and experience some
quickening or rather determining sensation when one among them
begins to discharge, and which causes them to follow suit imme-
diately. What this influence is would be very difficult to determine.
We know so little of the psychology of the lower animals that we
cannot even theorise on the subject with plausibility.

MICROSCOPICAL STUDIES IN MARINE ZOOLOGY,

BY JAMES HORNELL.

Stupy I—Hatictystus (LUCERNARIA) OCTORADIATUS.

HE pleasures of shore-collecting are many, and the one I fancy
the most enjoyable, is trudging about among gay weed-decked
pools and dyke-formed gutters in search of those delicate fern-like
sea-sprays, the Zoophytes. Here on this coarse brown Fucus are
numbers of serrate spikes of a Sertularian, bringmg to memory
Silurian graptolites, while in that pool tiny pinnate fronds anchored
to the very rock itself, bespeak a Plumularian. Coryne too on this
Jersey coast is not: infrequent, twining its long clubbed branches
among the finer weeds. But the vast sea-meadows or prairies as the
French call them, are equally prolific and harbour many beautiful
species never met with in rock pools. These meadows—where grows
the strange Zostera, a true flowering plant that has entirely renounced
fealty to its old home on dry land—are at times of spring tides fre-
quently left uncovered for short periods, and then we must watch our
chance. Campanularia and Clytia we may meet with, but by far
most conspicuous are rather large brownish bells of exquisite outlines
—that here and there are anchored to the long green blades of the
Zostera.

Such are easily récognized as Haliclystus octoradiatus, in these
parts the chief representative of the Lucernarians. In size these
bells (Fig. 1) are about one inch in height by nearly the same across
the oral face. The margin of this is drawn out into eight points,
each furnished with a bunch of closely set and numerous capitate -
tentacles. In the centre is the mouth, standing up quadrangular
and prominent. The four angles (of the mouth) mark the four
primary radii that can be made out in these animals, and are usually
known as the perradial lines or radi. In allied forms, eg. the
scyphistoma stage of Awrelia, these first radii are marked by the
appearance of the first four marginal tentacles. The second four
tentacles are alternate with the first and mark the secondary radii or
interradials. In Haliclystus their positions are the radial lines
beginning at points midway between the mouth angles. Thus they

16 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

alternate with the perradials. Between each primary and secondary
radius lies one of eight radiating genital bands. Their position is tech-
nically known as adradial. The margin of the bell just beyond the
extremity of each genital band is marked by a great cluster of short
capitate tentacles. The remaining external organs are eight con-
spicuous hollow bodies, each one lying midway between every two
groups of tentacles. These are probably vestigial sense organs and
have been termed colleto-cystophores. They will be referred to later
as_c-c. Four must be interradial and four perradial. Looking to
the internal anatomy, we find that the enteric or body-cavity is
divided by four delicate radiating walls or septa into four gastric
chambers—perradial in position.
represent the mesenteries of the Anemones—are interradial. From
their inner edges are given off numerous solid tentacle-like filaments
—the gastral filaments.

Those unfamiliar with these animals are reminded that the -
Hydrozoa are divided into the two great groups, Scyphomedusee and
Hydromeduse. The former includes, as principal order, those fleshy
medusz or Jelly-fishes—without. a velum (membrane all but closing
the mouth of the bell), with gastral filaments and with eight sensory
organs (tentaculocysts)—known so well under the forms of Awrelia
and Pelagia and termed collectively Discomeduse. Normally the
life-history of these animals is as follows :—A ciliated embryo (pro-
ceeding from the sexual or medusa stage), after a short period of
pelagic existence, settles down and becomes attached to some sta-
tionary object. A mouth forms at the free end, and sixteen tiny
tentacles appear. This form, x's to }-in. in height, is the scyphistoma
stage and is often termed the hydriform phase from its likeness to
the fresh-water polyp, Hydra. Soon transverse constrictions—stro-
bilation—cut the body into a rouleau of discs, appearing thus as a
tiny pile of sculptured plates. Each disc has eight arms, with a tiny
tentaculocyst at tip. This is the strobila condition. The discs
break off and begin a free swimming life, known at this period as
ephyrce, rapidly take on the form of ordinary Jelly-fishes, develop
sexual organs, and send out swarms of ciliated embryos to go through
the same strange cycle of life.

The Lucernarians form another order of the Scyphomeduse.
Contrasting their life-history with that of the large fleshy medusze
just related, we find that the Lucernarians produce in the genital
bands both ova and sperm masses. These give rise to ciliated
embryos which settle down quickly and develop without metamor-
phosis into the adult bell-shaped form.

Until recently Haliclystus and the related forms were consider sf
as being more or less unchanged descendants of the ancestral form of

MICROSCOPICAL STUDIES. 17

the Discomeduse, 2.e. prior to their adoption of the two well marked
stages—hydriform and medusiform—that now characterise their life-
history. Quite recently, however, Dr. C. Herbt. Hurst and the writer
arrived independently (“ Natural Science,’ Sept. 1893) at the novel
conclusion that the connection between the Lucernarians and the
Discomedusee is much more recent and close.. Thus we believe from
the review of considerable evidence that the former are descended
from a form having as well marked medusa-stage as Awrelia has, and
with well developed marginal sensory organs. Then by abbreviation
in the life-cycle, by a certain hastening of events, there were developed
genital products in the hydriform or scyphistoma fixed form. This
did away with the necessity for a free swimming sexual stage, and
being found advantageous, was permanently adopted by some—the
immediate predecessors of the Lucernarians of to-day.

Marginal sensory organs (e.g. tentaculocysts) can be only useful
among swimming forms (Hurst “Nat. Se.” vol. ui, part 16). Under
the changed conditions they became useless in the Lucernarians and
tended to become “ vestigial.” Such functionless organs are very
subject to variation—and the writer has found such to a really |
extensive degree in these bodies in Haliclystus. It is well known
that the origin of tentaculocysts is from ordinary marginal tentacles,
and it is to this form that the marginal bodies (c. cystophores) of the
species under description usually reverts. All gradations from the
normal form of ¢.-c. up to the normal tentacle can be traced, The
capitate terminations of the tentacles contain great numbers of -
nematocysts or stinging cells useful in paralizig prey, and the first
stage im reversion is marked by the appearance on the apex of a
¢.-c., of a tiny wart containing numerous nematocysts (Fig. 4). The
next shows a larger wart. In Fig. 5 this has a tiny stalk, while in
Fig. 6 there is a well pronounced peduncle. Again in Fig. 7, is
drawn a tentacle—one from a bunch of normal ones—where the
stem is bellied out, in fashion approaching the most abnormal of
the colleto-cystophores.

EXPLANATION OF Fics. 1 To 9, PuateE I.
Haliclystus octoradiatus.

Fig. 1. Two individuals adhering im natural postures to a blade
of Zostera. 1 8.

Fig. 2. Oral view :—z s. Interradial septum; g 0. genital bands;
m f. muscular fibres; g f. gastral filaments; s. sperm

mass ; ¢ ¢. colleto-cystophore ; ¢. group of tentacles, x 23.

Fig. 2a. Diagram of trans. section of body :—m. mouth; 7 s. inter-

radial septum ; pc. perradial chamber; g b. genital bands.

18 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

Fig. 8. Normal Colleto-cystophore, x 17.

Figs. 4,5 & 6. Abnormal series of same, x 17.

Fig. 7. Abnormal tentacle, showing shortening and thickening of
peduncle, x 17.

Fig. 8. Group of normal tentacles, x 30.

Fig. 9. Developing ovum, in optical section, x 25.

Stupy I]—TuHr PELAGic ANNELID TOMOPTERIS.

Occasionally among the contents of the tow-net there appears
this tiny paddle-propelled worm, active and sprightly in movement,
and so glassy and colourless as to be well nigh indistinguishable from
the water it moves in. The species figured on Plate I. averages
scarcely {-inch long, but its breadth seems very great in proportion
owing to the great length of the paddle-like feet or parapodia. The
head is very distinct. At the front border are two stout gracefully-
curved antennz (a), while just behind these is a pair of very delicate
processes (a+) which have also been called antenne. Next come the
most conspicuous appendages in the body—a pair of enormously
elongated tentacular cirri (t c.) In the centre of each one, and sup-
porting it, is a stout bristle, seen under a high power to be septate
(Fig. 13). Following these, about thirteen pairs of paddle-shaped
parapodia entirely destitute of sete, and consisting of a hollow cylin-
drical basal portion, expanding at the outer or distal end into two
foliaceous blades—upper and lower—which represent respectively,
the notopodium and the neuropodium of the typical annelid foot.
Every foot is controlled by two principal sets of muscular fibres
originating close to the median line in the body wall, one passing
obliquely forwards to be inserted in the anterior border of the foot,
the other backwards to the posterior border.

The mouth is situated between the tentacular cirri and leads
into a rather muscular portion, capable of at least partial extrusion
as a proboscis (Carpenter). This passes through a short cesophagus
into a long and wide stomach, reaching nearly the whole remaining
length of the animal. The body cavity is quite continuous. There
are no internal septa and the interior of the parapodia communicates
freely with the body cavity. The chief development of the nerve
system consists of a large anterior ganglionic mass, seated upon which
are two eyes, each composed essentially of a pigmented cushion
bearing two crystalline cones. In front of each eye is a large vesicle
of unknown function.

The sexes are separate. That depicted is a female and shows
how the ovaries arise from the growth of certain cells on the inner
surface of the peduncles of the parapodia. These cells grow to a

MICROSCOPICAL STUDIES. 19

very large size and then appear as very characteristic ova. Finally
these break loose and pass into the body-cavity. It is probable
that they normally pass thence to the water by rupture of the body
wall of the parent, but whether fertilization takes place prior to this
is uncertain. Curiously I have not lately met with the male form.
Carpenter describes it as having a long tail-like prolongation bearing
four or five minute appendages wherein are developed spermatozoa.
The tail-like prolongation is indeed given as being present in both
sexes of different species—but so far in the present species I have
not seen any trace of it in the females. Of males, I have not been
able to examine any.

The embryology is little known and we only become familiar
with the animal in an advanced larval stage. The earliest one
known to Dr. Carpenter belonged to a species having no posterior
antenne in the adult state, but in the larval it had no anterior
developed—while the posterior were very obvious and bore each a
distinct bristle, and were of comparative large size. The tentacular
cirri (¢ c.) were short, and approached the form of the succeeding |
partially developed parapodia, saving that they (the tent. cirri) pos-
sessed stout set like the posterior antenne. It is very interesting
to note that the species figured here (Fig. 10), shows in each
posterior antenna a distinct claw-like bristle, and this inclines me
to the belief that these organs are not antenne but are vestigial
tentacular cirri. The large tentacular cirri in the larval stage ap-
proach very closely in form to the parapodia and differ principally in
the presence of sete. The secondary antenne again approach closely
in larval life to the appearance of the tentacular cirri, so the inference
is Clear. It is only with the attainment of maturity, that this organ
becomes reduced and difficult to homologize, and even then, as seen
in our figure, there can in some species be traced distinct sete.
In the larger 7. onisciformis (Carpenter) this appendage however
entirely disappears in adult life.

Rosette-shaped organs have been made out at the bases of
certain feet; their function remains still obscure.

EXPLANATION OF Fics. 10 To 15, PLATE 1.

Fig. 10. Entire adult Tomopteris (female); a. anterior antenna ;
a. posterior antenna (vestigial tentacular cirrus); ¢ ¢
| tentacular cirrus; . a parapodium. x 17.
Fig, 11. Parapodium, nt. notopodium; nr. neuropodium ; ov. ovary.
Fig. 12, Ovum. ce. nucleolus or germinal spot; m. nucleus or
germinal vesicle; v. vitellus; v m. vitelline membrane,
x 200.

20 _ JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

Fig. 13. Seta from tentacular cirrus, showing septations, x 100.

Fig. 14. Eye showing two crystalline cones.

Fig. 15. Posterior antenna showing sickle-shaped vestige — a a seta
at a. X 100.

Stupy JIJ.—ANATomMy AND Lire HISTORY OF SALPA.

The great heat of the past summer was apparently very favour-
able to the development of surface-life im British latitudes. Pelagic
animals, usually rare, were this year sometimes abundant. Thus
Beroé, Medusce and Copepoda of southern species, Tomopteris and
the pelagic Tunicates, were taken much more frequently than I have
ever known before. For several days during August the tow-net
was full of a transparent colourless barrel-shaped Salpa, which
proved to be S. mucronata-democratica, Forsk. Most were adult—
such as those figured on Plate II. were quite young, only a few hours
severed from the parent and still showing remains of a placenta.

The large figures (16, 17 & 18) show this animal in various
aspects. In all the most striking features are seven great hoop-
shaped muscular bands. By comparing the three figures, the central
four will be seen to encircle the body completely, while the two
most anterior, together with the one most posterior, which les
in front of the exhalent aperture (a), fail to complete their respective
circles, one upon the dorsal, two upon the ventral aspect (Fig. 17).
On the dorsal side (Fig. 16) lying between and connecting the first
two hoops, are a pair of band-shaped muscles whose function is to
open the mouth. Another muscle of.a < shape (Fig. 18) lies
horizontally on either side of the mouth, performing the opposite
function of closing its two lips. The remaining muscular bands are
two strap-shaped ones, lying between the angles of the exhalent
aperture (a).

The body wall possesses externally a thick, semi-gelatinous layer,
which is the protecting tunic or test (¢), formed originally of a glassy
homogeneous secretion from the ectoderm or primitive superficial
layer of the body. In this test are subsequently found numerous
cells which have wandered in from the ectoderm. These are specially
numerous in the extremities (¢ c). The mouth or inhalent aperture
(0) les at the anterior end of the body; the exhalent (a) at the
opposite end on the dorsal aspect.

A great cavity is encompassed by the muscular hoops. An
_ anterior and a posterior division is formed by the presence of a
diagonal rafter or bar (br), stretching from a point behind the
ganglion (g), backwards and downwards to the beginning of the
cesophagus. This bar has been supposed to be the much modified ©

MICROSCOPICAL STUDIES. 21

remnant of the slit-perforated branchial pharynx, so well developed
in the simple Ascidians, such as Ascidia and Crona, the slits
having gradually coalesced, and being now represented by the two
great spaces which lie on either side of the branchial septum.
‘Recent research (Brooks’ “Salpa in its relation to the Evolution of
Life,” Baltimore, 1893), however, makes it probable that the an-
cestors of Salpa had never a complicated system of branchial clefts,
and that the present represents the little changed primitive plan.
At first, as Prof. Brooks points out, the ancestral Salp had an elon-
gated digestive tube without pharyngeal clefts. The anterior part was
distended and ciliated. Later on slime cells appeared, to retain food-
particles swept in by the free current of water passing through the
body. But this stream would also be lable to carry partially
digested food particles away—so the appearance of one or more
clefts in the distended pharyngeal part, allowing the water, after
bathing the slime covered parts, to pass freely away without coursing
through the intestine, would be a distinct advantage and would be
retained by natural selection. The chamber anterior to the so-called
branchial septum, therefore represents the pharynx—whule the pos-
terior chamber is the cloaca (cl), into which also empties the ali-
mentary canal by the anus. On the ventral surface of the pharynx
there stretches longitudinally a deep gutter with glandular walls, the
upper edges of which join along the greater portion of its length.
This appears optically to be a rod and is the endostyle (end); at
its front extremity it sends off two diverging ciliated bands (ac)—
the peripharyngeal bands or ciliated arc—which, arching upwards,
join again and pass into the branchial septum. The cavity of the
endostyle is ciliated, and the slime secreted by its glandular walls, is
_ passed on by the cilia into the peripharyngeal bands, and thence to
the ciliated surface of the branchial septum. At the posterior
extremity of the pharynx is the short cesophagus, passing into a wide
stomach ; thence a short intestine leads to the cloaca (cl). This
digestive tract in all pelagic tunicates is concentrated into a very
small space, and forms the only opaque mass in the body, and is the
so-called nucleus (nc). Water passing in at the mouth laden with
food particles, has the latter arrested by the slime covered ciliated —
arc and branchial septum, Passing through the two gill clefts the
water finds its way into the cloaca, whence it is discharged by the
exhalent aperture. The food particles arrested are sent by ciliary
action down the branchial septum and into the cesophagus.

The animals move through the water by repeated violent expul-
sions of water, due to contraction of the muscular hoops. According
as the water is expelled from mouth or exhalent aperture, the
movement is backwards or forwards.

22 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

The form figured was but a short time previous, attached to the
parent. At pl is seen a mass of cells marking the unabsorbed remnant
of the placenta ; el is a collection of large cells which are believed to
represent the urochord of the tail of an appendicularian-like ancestor.
It would thus also be homologous with the cartilage-like cord of the
tail of the tadpole larvee of sedentary ascidians.

The nervous system consists of a central ganglion (g) above the
anterior end of the branchial septum, with numerous nerves given off
to the different organs of the body. Upon the ganglion is a rounded
mass, the eye, containing dark pigment of horse-shoe shape. A little
way in front, is a ciliated sac situated immediately above a tongue-
shaped ciliated organ—languet—pendant in the pharynx and of
sensory value.

A heart is present beneath the alimentary canal, giving off a
large ventral longitudinal vessel. There is a similar vessel dorsally,
and the two are united by lateral branches. Vessels ramify in the
branchial septum. The peculiar blood circulation of Tunicates is well
marked in Salpa—after beating a certain number of times in one
direction, the heart remains still for a moment and then resumes
pulsating, but in an opposite direction, thus reversing the blood-flow
completely.

Life-history. The form under notice is asexual. The bud-shaped
part st is the first indication of the stolon, which in the adult develops
by growth and internal change into a long double-chain of tiny bud-
like salps (Fig. 19). When a certain size is attained, the chain breaks
free and swims away by rhythmic, and combined, alternate admission
and expulsion of water. These chain salps (Fig. 20) have quite a
different outward form, and a different—fewer—number of muscular
hoops. Each mdividual in the chain is connected with four others by
eight bars—two to each. Diagram Fig. 21 shows the method. The
chain salps are fully sexual; both male and female organs are
developed in each individual, but the female organs mature earlier’
than the male. A single ovum only is produced. It develops in situ
—being fertilized by spermatozoa that enter through the mouth of
the parent. It receives nourishment by the interposition of a true
placenta between it and the parent. It possesses a circulation
separate from that of the latter. When development is complete it
breaks loose and swims away. ‘This is the solitary asexual form
we figure. In turn it again gives rise to a chain of sexual salps.
Thus the life-cycle continually proceeds. |

a. Bd

MICROSCOPICAL STUDIES. 23

EXPLANATIONS OF Figs. 16 To 21.
Salpa mucronata-democratica.

Fig. 16. Dorsal view; Fig. 17, ventral view; Fig. 18, lateral view.
All solitary asexual form. ¢. test; ¢n. nuclei of test ;
m. mouth or inhalent aperture; ph. pharynx; ae.
peripharyngeal bands; end. endostyle; f. languet; br.
branchial septum; 7. nucleus or gastral part of alimen-
tary canal; cl. cloaca; a. exhalent aperture ; el. eleoblast ;
pl. remnant of placenta ; st. proliferous stolon ; g. ganglion
with eye seated thereon and nerves radiating. Muscular
bands are distunguished by brown colowring. x 30.

Fig. 19. Posterior part of body of an adult solitary zooid, showing
the development of the proliferous stolon s¢. into a chain
of buds. 1. nucleus. X 6. | :

Fig. 20. 3 chain salps showing method of connection. emb: embryo,
m. nucleus. X 23. .

Fig. 21. Diagram of a double row of 8 salps, showing plan of

attachment. Two connecting bars linking every two
individuals,

View of the Jersey Biological Station from the sea.

24 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

IMPORTANT NOTICE.

The four microscopical preparations illustrated and described
in the preceding pages, form the first quarterly instalment of a series
of 14 subscription slides now in course of issue. There will be
included fine mounts of entire organisms, ¢.g., New Hydroids of great
beauty, Medusoids, Tomopteris, larval annelids (Polynoé, Nereis),
rare larval crustaceans, expanded Polyzoa, pelagic Tunicates (Salpa,
Doliolwin), &c., also type slides of British Sponges, anemones and the
like. The remaining slides of the series will be treated in the same
detail as are the four which have received attention in the preceding

pages.
The slides will almost entirely be new to our lists—but should

subscribers have a duplicate of any slide sent, we will willingly give
an opportunity of allowing another slide to be chosen in substitution.

This opportunity will we think be required in only two instances,
viz.: Lucernaria and Plumularia. Several subscribers who have
these two slides, have requested us to include these two animals for
illustration and description in the pages of the Journal, so if any
subscriber having these will send a post-card naming another slide
which he may wish substituted, we will arrange accordingly. A list
of recent mounts will be found on the cover, and from among these a
suitable substitution will probably be found.

The subscription, inclusive of the Journal and the 14 slides,

is 21/- post free. Sample sets will be sent on approval if desired.
Further particulars on application. The Journal may be had
separately, and will be supplied post free for 6d. per number, or
2/- per annum. ~Address: Sinel and Hornell, Biological Station,
Jersey. ;

KKRKRKARRRRRR-

EXCHANGES WANTED.

Literature upon the Hydrozoa and the Annelida; well preserved
fossils (named); foreign echinoderms and crustaceans, also centipedes
and scorpions in spirit. Exchange in micro. slides, zoological
specimens, &e.

TO CORRESPONDENTS.

All communications for the Eprror to be addressed to the
BIOLOGICAL STATION, JERSEY.

Original notes on Marine Life are invited; while technically
correct, they must however be written in an interesting style,

Advertisements to be sent to the same address.

Journ. of Mar. Zool. and Microscopy. | Vol. t., Pl.

ea
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82 ys

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Jas. Hornell, del. ad. Nat.
JERSEY BIOL. STN. HALICLYSTUS AND TOMOPTERIS.

Vol. 1., Pl.

SALPA MUCRONATA—-DEMGGRATICA.

Journ. of Mar. Zool. and Microscopy.

JERSEY BIOL. STN.

as. Hornell, del. ad. Nat.

The Journal of Faring Zoology
and Aiicrosuogn :

A PLAINLY WORDED BIOLOGICAL QUARTERLY.

You. I. No. 2. FEBRUARY, 1894.

THE REARING OF STARFISHES IN CONFINEMENT.

BY H. J. WADDINGTON.

ROBABLY of all the Echinodermata, Asterina is the most easily
kept in small aquaria. The conditions for successful develop-
ment are very simple, and the results more than repay the trouble
expended. -

In 1889, I commenced keeping a few Asterina gibbosa in a
small bell-glass holding about 1 gallon of water. These were fed
on small pieces of oyster every week, and remained in perfect health.

In May the ova were discharged, they rapidly rose to the surface
of the water, coalesced and quickly decomposed.

The failure, in this instance, was no doubt owing to the seawater
being above the normal density. In 1890, the ova from the same
Asterine were again discharged, and although I succeeded in entan-
gling a few among the filaments of some conferva, the remainder
rose to the surface and decomposed as on the former occasion. It
was evident that the conditions were unsatisfactory and must be
modified. I placed the aquarium containing the Asteronw, and
which was covered with a piece of glass, close to a window with a
S.W. aspect, and allowed it to have all the light possible. In a short
time the aquarium was covered with vegetation which increased
rapidly until May, 1891.

The ova were now deposited on the side of the aquarium, each
ovum quite separate. In no case were two ova touching one another.
The subsequent development was all that could be desired. I was
equally successful in 1892 and 1893.

The ova are deposited towards the end of May (26th or fae.
in each of the years 1891-2-3 there has not been a variation of
more than two days in the date of deposition, The ova are not
all deposited at one time, as in 1892 from two Asterinw were
deposited 3 patches of eggs at intervals of a few hours. =. |

26 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

The ova adhere to the vegetation on the side of the aquarium
and show little motion for 2 or 3 days. They are very easily removed
with a glass tube, and may be returned to the aquarium after micro-
scopic inspection without any deterioration. The development may
be watched under the microscope from the first day up to maturity.

For isolating the ova nothing is better than thin wine-glasses
narrowing to the bottom, broken at the stem. These float readily
in the Aquarium, and the small quantity of water they contain
(4 to 1-oz.) remains perfectly good. In fact each becomes a miniature
aquarium, the temperature of course bemg that of the larger
aquarium in which they float.

For preserving the Asterinw as permanent objects and at any
stage of their development, the best method is to use Cocaine
Hydrochlorate and to allow them to come under its influence very
gradually. In this way they die without undergoing any distortion,
and may be transferred to weak Alcohol of 30 or 35 /, and preserved
in this fluid, or carried through higher percentages of Alcohol to oil
of Cloves, this removed with redistilled Turpentine and then mounted
in Canada Balsam.

A HANDBOOK TO THE CopEPoDA.—We have before us ‘‘ A Revision of the
Copepoda of L’pool Bay,” by Mr. 1I.C. Thompson, F.L.S., and find much to praise
therein. It is indeed a happy idea to give small outline sketches of each animal
dealt with, and to group those of related species on the same page, as is here done.
Considered as a ready reference guide, it will be found extremely useful to all,
anid especially to the junior, students of this order. This paper appears in Vol. VII
-of the Trans. L’pool Biol. Soc., and we take this opportunity of suggesting to the
Committee the desirability of adopting the plan pursued by the Royal Dublin
Society, to wit, the selling of its more important cssays separate from the
‘main volume at a correspondingly lower price. The major publications of the
Society would in this manner become much more widely known.

A New Bionocican Trxt-Boox.—Mr. H. G. Wells is to be heartily com-
plimented on the completion of his useful Text-book of Biology (London: W. B.
Clive, 1893). Part II, devoted to invertebrates and plants, is now before us, and in
every way is a worthy successor to Part I (vertebrates), now so greatly esteemed
in teaching circles. We feel sure Part II will quickly be received into equal favour,
and we heartily recommend it to all students of “ types.” ;

The mode of illustration marks the trial of a novel experiment. Many folding
-plates are provided, and in order to prevent scamping of the practical work of
dissection at first hand, the figures are of such a nature, that in most cases it is
difficult for the tyro to gleam therefrom proper enlightenment of the text, except
he be concurrently making the equivalent dissection, in which case the diagram
will give him clearly the necessary information regarding the identification of parts.
_ Such an arrangement spoils the artistic value of the work, but we appreciate the
motive and believe the plan will answer admirably the purpose intended. The happy
‘mean is struck 'twixt Huxley’s too drastic “no illustration ” and the over elaborate
‘drawings of others, that by their completeness, delusively tempt the student to
avoid the drudgery of dissection.

THE CLEANSING OF THE LITTORAL BY THE
LUGWORM (ARENICOLA MARINA).

BY JAMES HORNELL.

E are accustomed to admire the vast vivifymg, or rather
oxygenating, influence of the breakers. We watch them
dashing and surging, frothed with the commingling of air globules,
and then in full confidence of the purifymg power thus imparted
to the sea, we expel the noisome sewage of our cities by thousand
mouths into the littoral. I do not dispute that results appear to
justify this confidence, but I contend that the waves must not receive
the entire credit. Granted that sewage and decaying matter can
be brought to float and toss hither and thither with the waves, the
transformation is wonderfully rapid. But in fact, much sewage
laden heavily with organic matter soaks downwards into the sand
and clay and gravel, after ejection from the sewer mouth. And not
sewage alone. The sand of the shore has a natural tendency to
keep on the surface. Throw upon it decaying matter and if not
carried away, a day or two will find it buried well out of sight.
Like too many of the conventional masks that we fit on as filmy
covers to our social horrors, so the sand is apt to hide as a clean
but thin crust, great deposits of noisome foeetid clay, black and
malodorous with the concentration of ever present putrefaction.
The purifying power of the waves fails to influence beyond the
surface layer of sand and the accumulation would go on uninter-
ruptedly, ever extending further down, if other cleansing power did
not come into operation. Putrifying matter in solution we know
tends like other watery fluids to percolate downwards. Hence a
long period of quiet should show the clay at a considerable distance
from the surface, more saturated with filth than the upper and newer
layers. In reality, we find that the most evil smelling and blackest
region is but a few inches from the top, and thence downwards the
contamination decreases until a certain minimum is reached, which
in all lower depths is fairly constant.
As I have pointed out, this is not what we would naturally be
led to expect. The key to this apparent contradiction I owe to my

28 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

old friend Mr. Isaac E. George, who suggested to me the influence
of the common lug-worm (Arenicola marina, Linn.) This animal
abounds on all the sandy and muddy stretches of our coast. Every-
where as the tide leaves bare the shore, its castings appear in
myriads. On sandbanks well to sea, where decaying matter is
scarce, Arenicola is found in small numbers, whereas along the
shore, especially in the higher littoral towards high-water mark, its
abundance is limitless. Here in Jersey is a region where after
storms, vegetable matter in the form of sea-weeds (Fucus, Laminaria,
Chorda, &c.), with a lesser though not inconsiderable amount of
animal débris, is piled up along the farthest tide-reached limits,
and a good portion of this soon becomes buried upon the beach.

Now Arenicola in habits, is the marine counterpart of the
earth-worm. Like the latter, it is without any biting parts in the
mouth. It has no means of capturing prey, and contents itself with
swallowing the sand and mud it burrows in, extracting therefrom
what organic matter 1t can. Within limits then, the more putrefied
matter there is mixed with the mud and sand, the richer is the lug-
worm’s diet. This explains how it abounds in more than common
number close to the outlets of rivers, in harbours and docks, and
also high upon the littoral—these places bemg where much decom-
posing matter is deposited. Worm castings everywhere represent
the sand and mud passed out of the worm’s body in a purified state,
freed from organic matter through such having been absorbed into
the nutritive fluid of the worm’s body.

Darwin astonished the world with his calculations of the magni-
tude of the cleansing operations carried on by the ordinary earth-
worm. On my part, I cannot give figures, but considering how
the castings of lug-worms are so numerous as practically to touch
one another; that we see them renewed twice a day as the tide
uncovers the sands, and that such visible renewals represent not
one tenth of the work that goes on when the tide returns to give
more congenial conditions, we may be certain their workings over
areas of equal extent, are much more momentous than even those
of the earth-worm. It must, too, be borne in mind that the average
size of the lug-worm is greater than that of the earth-worm and
that on the average, though great, there is less organic matter in
sand and mud than in earth. Hence to obtain equal amount of food,
the lug-worm must swallow a much larger quantity of matter than
its land counterpart. As I have said, there is less organic matter
in littoral sand and mud than in earth, yet what there is, is infinitely
more evil smelling. The organic matter in earth is largely woody
fibre—slow of decay—and besides, as gases are evolved, such are lost
rapidly by diffusion in the atmosphere, to which the earth particles

CLEANSING OF THE LITTORAL BY THE LUGWORM. 29

are freely exposed. On the other hand, similar diffusion is infinitely
less rapid under water and indeed, the gases of putrefaction are
in sand and mud virtually closely confined. Again, decomposing
matter in the marine “soil” is without the slow-decaying fibrous
matter so common in earth. Water plants do not require woody fibre,
and they accordingly offer no resistance to decay. There is also
probably more decaying animal matter in sea “soil” than in earth.

The full value of the cleansing operations of the lug-worm is
not easily to be assessed. Without this humble worker, the littoral
would in many places become a veritable cesspool, calling for costly
human intervention, at least at those spots we dub as seaside health
resorts. Left alone, the wrack or seaweed cast up by storms would
putrefy, and whenever the thin covering layer of mud or sand were
removed, noisome gases in horrid volume would arise to vitiate the
erstwhile pleasant sea breeze. I do not draw a fancy picture. A few
weeks ago, on a tramp along the west coast of our little island,
searching for stray items geological, I tried to explore a little bay,
perhaps the most used of any in the island by farmers during the
wracking season, at that time in fullswing. I write “ tried to explore ”
advisedly, for the stench that rose from the bay was more than my
nostrils were prepared to endure. I stayed just long enough to
discover that the odours arose from the decay of Fucus and Lamimaria
dropped by the carts as they returned up the slip way, from off the
shore. Some weed lay in forgotten corners above high water mark,
but the main body of the stench arose from the pebbles, gravel, sand
and pools. A greyish black slime enveloped and contaminated every-
thing beneath foot. Landlocked as the little bay is, the air hung
dense and heavy as that of a charnel house. One cannot exaggerate,
strange as it may seem. In this instance, the accumulation on the
beach of decomposable matter is too rapid for the lug worm to
contend with. :

While arguing the value of the cleansing of the littoral by this
worm, I do not, however, wish to convey the idea that finally the whole
of the decomposable matter is eliminated—only the bulk is removed.
A certain residue is left, explainable by reason of the worm
finding starvation conditions present, when the organic matter is
decreased to a definite point; that reached, the worm removes to
where more food matter is present mingled with sand and mud.
Thus in a growing deposit, the progress of the lug-worm will be
upwards. As the deeper layers are exhausted of their carbonaceous
food supply, so the lug-worm gradually ceases to burrow down into
these and if new layers are all the while being added at the top, so
the dense black band which denotes the maximum presence of
unexhausted organic decay does not remain stationary or spread

30 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

downwards, but continuously ascends, the lower layers becoming
cleared by the activity of the lug-worm while new layers are added
above. Pale bluish-grey is the color of the sandy clay as left by
lug-worms and here a curious point comes in. What but this color is
the prevailing hue of our shales and marls? Worm tracks and
castings of worms certainly closely allied to Arenicola are common
fossils in rocks from very early times, ¢.g. the burrows of Arenicolites
in the Cambrian strata. Their food supply must have been much
the same—decaying vegetable matter. Thus the work they per-
formed was similar, and to this ceaseless activity ever coping with
the continuous accession of new decaying matter, we must look for the
explanation of the very sight admixture of carbonaceous matters in
the many sand-stones and shales of varied geological age, that by the
associated castings and other evidence, are plainly marked as having
once existed as the sandy and muddy shore lines of ancient seas ; seas
subject to the same storms as ours; seas where the jetsam of weed
was thrown in piles upon the beach and where when covered up by
surface sand it decayed and was purified by the life activity of the
lug-worm, just as is happening continuously in the present. Truly, if
the history of the past be written in the rocks, it is among the events
of the present that we must search for the alphabet wherewith to
decipher the words and sentences of the book.

Pure CHEMICALS.—Very often we are asked for the name of a firm supplying
absolutely reliable Chemicals, or such as are in so little demand as to be difficult to
procure in an ordinary way. It gives us, therefore, special pleasure in naming
Messrs. Harrington Bros. of Cork—whom personal experience has shown us to be in
every way worthy of confidence. What is also important, is that their prices
are most reasonable.

British ECHINODERMS.—We are glad to welcome a goodly addition to our
knowledge of British starfishes and sea-urchins, in the form of the latest British
Museum Catalogue. Prof. Jeffrey Bell, who is the author, has here massed together
the essentials of much important literature, and sorted out many tangled skeins of
nomenclature. The task, weighty like all of its kind, has been conscientiously
carried through, and without vain striving after effect. Intended primarily as a
work of reference the book is without that fascination for the mere nature lover,
present in such high degree in Forbes’ classic volume. Hence we cannot advise
any but the more earnest students of the group to add it to their shelves.

A few transcription errors occur. Thus on page 119, Ophiura neglecta is twice
given as Forbes’ name for Amphiura elegans, when in reality, Forbes, in both the
cases referred to, wrote Ophiocoma neglecta. Again on page 171, Jersey is given as a
habitat for Echinocardiwm pinnatifidum. To our positive knowledge, the island
of Herm is the nearest point to Jersey, where this animal occurs. By the way, it
would be a most useful plan, if authors of landmark works such as the one under
notice, were to publish a pithy list of errata and corrigenda in some scientific
periodical after the lapse of say a year from publication. Errors will creep in, be
one ever so watchful, and for want of a simple safeguard such as the above, are
needlessly endowed with, too often, a surprisingly long existence.

ON THE LOCOMOTION OF THE MOLLUSCA,.

BY JOSHPH SINEL.

ONSIDERING the great variety of form assumed by the members

of the group Mollusca, one is prepared for a corresponding diver-

sity in their modes of locomotion, but perhaps few, éxcept those who

have made the group a special study, have considered how very varied

these are, and what different parts of their organization are employed
to this end.

For instance, the general reader may be surprised to hear of snails
that jump, and of cockles that can proceed over dry land by bounds
of several yards. In fact, so erratic are these animals in their modes
of travel, that a general outline of such may not be void of interest.

Taking first the Lamellibranchs, or Bivalve Molluscs, and confi-
ning ourselves in all cases to the adult form, we find that while some
are stationary, firmly cemented to rock or stone by one of their valves,
é.g. some of the oysters, or moored by a tassel of strong threads (the
byssus) after the manner of the common mussel, the majority have
the power of slowly trailing themselves, over, or through, the
sand or mud by means of the foot, the fresh water mussel affording a
familiar example. Others, notably the Pectens, have the power of
swimming. ‘This is effected by the sraart opening and closing of the
shell, and in one member of this family, Zima, this faculty exists to
such perfection as to be best described as a graceful undulating flight
through the water, each closure of the shell propelling the little
animal some eight or ten inches.

This faculty of swimming, combined with the beauty of the
pearly striated shell, and the surpassing gracefulness of the long
orange and vermillion fringe of its mantle which forms streamers
behind, render this without a doubt the most attractive member of
the Mollusca.

Then, at least one member of the class has very considerable
leaping power, this is the marbled cockle, Pectunculus glycymerts.
In Jeffrey’s British Conchology (Vol. 11, p. 167) it is stated
“This animal does not execute a direct progressive locomotion, but
only turns the shell round on its dise or from side to side.”

Very different from this has been the experience of the writer
who, on several occasions when collecting at night at low tide limit
on the great shell gravel reaches of La Rocque point, Jersey—where
this molluse abounds—has been fairly pelted with them as they

32 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

leaped to meet the rising tide. These leaps ranged from three or
four to six feet with a trajectory rising two feet or more—their course
always seaward.

This phenomenon the writer has not observed by day, so cannot
say how the movement is performed.

Then we have on these shores, one Lamellibranch, Galeomma
turtont, which takes up the mode of gastropod locomotion, and with
valves set wide open, creeps over the rock with its flattened foot.

Next we come to the Gastropoda. Here the common land forms,
snails and slugs, afford familiar illustration of the usual mode of
travel—crawling by the alternate extension and contraction of the
muscular foot. This mode is common to all except perhaps the
pelagic Heteropoda, for even the pelagic Lanthina, that carries a
float, has the power of crawling; but a few offer the following
additional methods :—

Strombus, a cousin of the whelks can ywmp; some of the same
tribe Lachesis, together with many of the Opisthobranchs (Aplysia,
Doris, Eolas, &c.) have the habit of swimming foot uppermost on the
surface of the water. Movement by this means is, of course, very
slow and imperfect. A modification of this system, which is better
described as a means of transport than of travel, the writer has
frequently observed in Holis,—this is its suspension by means of a
thread of mucus, from a globule of the same, which, entangled with
air, floats on the surface; the position of the animal when so sus-
pended being always doubled up, hedgehog fashion, with the back
downwards. fe

Next in order, we come to the Pteropods, or sea butterflies.
These Molluscs are pelagic and their means of progression is by the
flapping of their large wing-like fins.

Finally, in the Cephalopoda, we find the highest development of
travelling power. The Octopus can propel itself swiftly backward by
the expulsion of water from the mantle sac, an average size specimen
(say one of two feet in length of body and arms) can propel itself by
this means, at a rate of ten or twelve feet per second. It can also
swim forward, by a spider-like movement of the arms, with consid-
erable speed ; it is in this manner that it usually darts on its prey
from its lair. By means of the suckers on its arms it can crawl and
climb nimbly over rocks and stones; and over smooth bottom, by the
employment of the tips only of its arms, it can be said to walk.

Loligo, Ommatostrephes, Sepia and Sepiola dart backward in
the same manner, and by the same means, as the Octopus, but: yet
more swiftly, and the two former, at least, swim forward with almost
equal ease by means of their fins—the arms in this case being
brought together to form a point.

THE COLOUR SCALE IN MARINE ANIMALS,

BY JAMES HORNELL.

N a previous note on colouration (p. 8), I had occasion to chronicle
the fact that a chromatic Scale similar to that found in the
evolution of flowers, and with which Grant Allen and others have
made us so familiar, can be made out in the colouring of marine
animals. As the subject is interesting, I may be allowed here to
amplify the statement.

The presumed order of evolution being from white, through
yellow, orange, red, and purple to blue, we would expect the more
primitive colours—white and yellow—to characterise the more simply
organised species in each phylum or great division of the animal
kingdom. As complexity in structure progresses, we may naturally
look for corresponding advance in the colour scale. The advance
will however not be made without purpose; some powerful reason
warning, mimicry, sexuality, &.—must be present or the primitive
colour will not be forsaken, and again through the working of the
great law of atavism or reversion, so soon as the existing cause ceases
or waxes faint, the advanced colour will in time be renounced, and
the more primitive resumed.

Blue, the highest grade, is, as we are thus led to expect, seldom
found in marine creatures. On our own coasts I can recollect only
the sometimes lilac coloured sponge Chalina montagut; several
purple sea-urchins, Spatangus purpureus, Bryssus lyrifer, Strongy-
locentrotus lividus, and Spherechinus granularis ; some partially
blue Copepoda ; the Lobster ; several purple and blue compound
Ascidians, and some partially blue fishes.

These animals are all among the most highly specialized animals
of the groups or classes to which they respectively belong. Among
the sponges, the Silicispongiz, to which Chalina belongs, stands
practically at the top—the great complication of the canal system,
and the wonderful development of the mesoderm placing this
order far in advance of the members of the other great sponge order,
the Calcispongize. These latter, thus characterised by comparative
simplicity, are all but entirely white. One only do I know of other
colour, Ascetta coriacea, and then the hue, pale yellow or orange,
is not even normal, being merely a varietal colouring.

The sea-urchins are among the most highly specialized of their
phylum or indeed of any animals; the blue splashed Copepod, Ano-
malocera pattersoni is among the most highly organized of his order,
and the Lobster, again, is in many respects the foremost of our
macrourous (long-tailed) crustaceans. As to the Ascidians, there is no
question that the species sporting blue and lilac colours are among the
most special, for as such are counted the crusting compound Ascidians

od JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

of the family Leptoclinide, of which on this coast I know a bright
sky-blue species, and others of lilac and of purple in varying shade.
Many fishes are striped (male of Labrus miaxtus) or otherwise
ornamented with bright blue; but only among the Teleostei, the
most specialized of fishes. There are certainly cartilaginous fishes
to which the term blue is affixed, such as the Blue Shark, but such
colour is rather grey or drab and can only be termed blue by a
stretch of courtesy.

All this is strong evidence, but we can obtain further confirma-
tion by looking at the problem in a different light. Presuming
blue to be furthest from the primitive colour, such hued animals
must have passed through the scarlet stage ata later date than the
yellow, and we should expect the species and genera nearest related
to be of the scarlet hue rather than of the yellow. And itisso. The
nearest relations—and less specialized too—of the lobster on our
coasts, the Norway lobster (Nephrops norvegicus) and the two
craw-fishes Palonurus and Scyllarus are all scarlet, not yellow. The
star-fishes, more primitive echinoderm forms than the so frequently
purple coloured sea-urchins, seldom or never in our seas get beyond
yellow, orange, and scarlet. Regarding the Ascidians, the blue and
lilac Leptoclinidee have, as most closely related species, several of deep
scarlet and blood red, a few of orange, and but one or two of yellow
and of white.

The converse holds true. Such animals as cling with intensity
to the primitive white, show in their nearest coloured relatives the
light end of the scale, yellow and orange, rather than purple and blue
or even scarlet. The sponge phylum being more homogeneous and

showing less specialization than any other serves admirably as a test,

and as already mentioned the only calcareous sponge I know to
be ever coloured in our waters, viz., Ascetta coriacca, is normally
white, occasionally canary yellow, and only rarely orange. The
Plumose anemone (A. dianthus) normally white, has a pale orange
variety, and again, the snowy Alcyoniwm digitatum is also occa-
sionally orange.

To summarise these conclusions :—

I. White is the prevailing colour of the least specialized animals
in the most primitive phylum of the Metazoa—viz.: the
calcareous sponges.

II. Yellow and orange follow closely and are the characteristic colours
of those coloured animals most closely related to white ones.
III. Blue and purple are characteristic of the most specialized
among the most highly developed phyla—eg. the sea-
urchins among the Echinoderms, the lobster among decapod
Crustaceans, and the crusting compound Ascidians.
IV. Animals most closely related to blue and purple species, are
mostly scarlet, red, or deep orange in hue.

MICROSCOPICAL STUDIES IN MARINE ZOOLOGY.

BY JAMES HORNELL.

Stupy IV. Sponges; AN INTRODUCTORY SKETCH.

HE Jersey shore between tide-marks is veritable “ Spongeland.”
Scarlet, brick-red, orange, yellowish green, yellow, white, grey,
and black patches clothe the rocks in chequered mantle, and with the
vieing colonies of gaudy-colored compound ascidians, relieve in a
pleasant manner the sombre brown of the fucus-covered rocks. Yet
common though sponges are, they remained until comparatively
recent years a puzzle group to naturalists. Grant is generally
eredited with having, in 1825, given the first great impetus in the
right direction, by his observations on the passage of minute water
currents into the sponge by numerous small pores and their emergence
by a few large openings. The following extract from the third
edition of the Encyclopeedia Britannica, 1797, will, however, prove
that our fine old pioneer naturalist, London merchant Ellis, should
rather have the credit :—“ Mr. Ellis, in the year 1762, was at great
pains to discover these animals. For this purpose he dissected the
spongia urens, and was surprised to find a great number of small
worms of the genus of nereis or sca-scolopendra, which had pierced
their way through the soft substance of the sponge in quest of a safe
retreat. That this was really the case he was assured of, by inspect-
ing a number of specimens of the same sort of sponge, just fresh from
the sea. He put them into a glass filled with sea water, and then
instead of seeing any of the little animals which Dr. Peysonell
described, he observed the papille or small holes with which the
papillee are surrounded, contract and dilate themselves. He examined
another variety of the same species of sponge and plainly perceived
the small tubes inspire and expire the water. He therefore concluded
that the sponge is an animal, and that the ends or openings of the
branched tubes are the mouths by which it receives its nourishment,
and discharges its excrements.”

The same work describes “Spongia,” as “a genus of animals
belonging to the class of vermes, and order of zoophytes. It is fixed,
flexible, and very torpid, growing in a variety of forms, composed
either of reticulated fibres, or masses of small spines interwoven
together, and clothed with a living gelatinous fiesh, full of small

36 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

mouths or holes on its surface, by which it sucks in and throws out
the water.”

Now to trace something of the progress that has been made in
the study of these animals during the last hundred years. By most
authorities, sponges are granted a separate phylwm or branch, in the
genealogical tree of the division Metazoa or multicellular animals.
They form the lowest or least specialized phylum ; the name applied
to them collectively being Porifera. A short summary of the most
important points in the anatomy of the chief types of sponges is
however necessary to the intelligent understanding of such position
in the scale of nature.

The most primitive form of sponge organization is well seen in
the very simple sponge, Ascetta prvmordialis, so minutely described
by Heckel. In appearance, Ascetta is a tiny, thin-walled, goblet-
shaped animal that lives anchored by the narrow stalk end to rocks
and weeds. At the free end is a wide opening (Pl. iv. Fig. 1), the
osculum, while minute holes, pores, pierce everywhere through the
thin walls and open into the great central cavity or paragaster. These
walls, thin as they are, are of considerable complication, for three layers
of cells can be made out, an external, ectoderm, composed of a single
thickness of more or less mosaic-like cells; a middle, mesoderm,—
here extremely thin—and lastly an internal layer, endoderm,
composed in this sponge of oval shaped cells, each provided at the
free end with a well-marked circular upstanding collar, from within
the centre of which a strong whip-like thread or flagellum arises.
Such cells are termed flagellated collar cells or shortly, flagellated
cells—technically choanocytes.

In the first four figures on PI. iv, the outer black lime repre-
sents both ectoderm and mesoderm, while the shaded layer stands
for flagellated cells. In the living sponge, the activity of the flagella
of the endoderm sets up minute currents of water flowing through
the numberless pores into the paragaster where nutrient particles
are picked up from the water and effete matter cast back. Hence
these currents, now gathered into a strong body of water, are directed
out through the great osculum at the summit of the sponge. Sponge
circulation is always fundamentally similar, even in the most complex :
ingress by very small openings, egress by a single large vent.

But to return to our Ascetta. Essentially its structure is a
thin walled sac, with pores opening direct into a great paragaster
lined with flagellated cells.. This arrangement of water passages,
technically Canal System, is the simplest known, constituting what
Heeckel named the primitive Ascon Type (Fig. 1).

Complications are frequent, but the fundamental feature of
flagellated paragaster remains stable, Thus in our common Ascetta

MICROSCOPICAL STUDIES. Sib

coriacea, budding, and branching, and anastomosing long continued,
produces a colonial network having a long ramifying paragaster
with numerous oscula. An intermediate form, Ascaltis botryoides,
helps us better to understand the change, for here the buds while
remaining attached to the parent and with their paragasters in free
communication with the parental one, have each a separate osculum.
Thus in an old colony, we can trace distinctly of how many indi-
viduals it is composed, by counting the number of branches, for
each possesses a single osculum, the sign of the sponge unit.

A foreign species furnishes another interesting complication
shown in Fig. 2. The walls become pushed out into numerous
radial tubes, mto which the flagellated coating of the parayaster is
extended, and into which the pores open. Thus the extent of flagel-
lated surface and of the pore area is largely increased. The name
Chambered Ascon is applied to this form.

The next sponge type given us by Heckel, the Sycon, is a
natural outcome of the Chambered Ascon, and in simplest organization
has the same structure minus the flagellated lining of the primary
paragaster. The cells of this become practically identical in form with
those of the ectoderm by loss of flagella and collars. Thus the Sycon
may be defined as a Chambered Ascon where the flagellated cells are
restricted to the radial tubes. Figs. 3 and 4 graphically exhibit
this change. These two types are practically restricted to the
division of sponges possessing a skeleton of calcareous spicules, which
is thus marked out as the lowest or most primitive division of the
Porifera, and consequently also of the Metazoa.

. The third and highest type of sponge canal system, called
by Heckel the Leucon from its being characteristic of the family
Leuconide, and by Sollas the Rhagon, is accompanied, or rather
caused, by a great development of the middle layer of the body, the
mesoderm. This occasionally reaches immense proportions (see Fig. 8)
and as the paragaster does not Share in this increase, the rather
dwindling, it is obvious that the pores must have, superadded, long
canals to enable the water to pass through the thickened walls into
the paragester, or even into its out-growing chambers. One origin
of the Rhagon is probably from the Sycon, as shown by the hypo-
thetical Figures 5 and 6; Fig. 5 is practically a thick-walled Sycon,
the paragaster pushing into the mesoderm fairly large rounded
chambers, henceforth to be called ciliated chambers. Narrow tubes,
incurrent canals, connect these with the pores on the surface, and
either one or several may serve each chamber. - The flagellated form
of endoderm is entirely confined to the chambers. The next step
is where the mesoderm still thickening, the chambers lose their
direct connection with the central cavity and become connected by

38 JOURNAL OF. MARINE ZOOLOGY AND MICROSCOPY.

a fairly long excurrent canal. The fresh-water sponge is organized
essentially upon this plan.

In the Leuconide, e.g. Leucandra nivea, a further stage, Fig. 7,
can be made out, where instead of the excurrent canal of each
chamber pouring its tiny stream direct into the paragaster, those of
large groups of chambers are collected, as a river on its journey to the
sea gathers its tributaries, into a great and wide, but short stream
emptying by wide outlet into the central cavity.

This, the true Leucon type, is what Sollas terms the Aphodal
type of Rhagon. A further development, the Diplodal Rhagon, is’
reached when the incurrent canals, in this highest type usually
restricted to one to each chamber, arise not singly and separately,
but rather in the manner of the numerous branches into which a
great river divides and sub-divides on its way through its delta.
A large and wide tubular cavity, the sub-dermal chamber, pene-
trates the crust of the sponge, and from this, numerous wide incurrent
canals lead inwards, throwing off at intervals still smaller tubules,
each of which feeds a ciliated chamber. The excurrent canals remain
the same as in the aphodal type. Often the sub-dermal chamber is
arched over by a finely perforated membrane, the pore area, a natural
filter against the entrance of enemies and coarse particles. A little
below this filter membrane (inwards) is usually a well defined sphine-
ter muscle, adapted by its power of contraction to completely or
partially close the entrance to the water canals. The portion of
the large chamber inward of the sphincter has received the name
of Subcortical crypt.

A moment’s consideration will show the great advantage that
will accrue to the sponge if the soft ground tissue be laced with
a network of intertwining fibres or supported by a cunningly arranged
scaffolding of strong and rigid rods. Without some such support,
the flagellated chambers would be apt to collapse and perform
their function indifferently, if at all. Based upon the nature of this
supporting skeleton, whether or not it is composed of calcareous
spicules, we get our two first great divisions, the Calcarea and
Non-Calcarea. The latter are by some termed Fibrospongie, because
of a lacework of horny fibres more or less developed. But the
majority of the Non-Calcarea have, superadded, spicules formed of
silica (Silicispongiz), while others again want both spicules and
fibrous skeleton (Myxospongie). The Silicispongize are split up into
three orders according to the shape of the principal spicules
(megascleres), thus :—

Order I.—MoNAxoNnIDA, megascleres simple, rod-shaped (Figs. la
and 2a, Pl. i).

Order II—TETRACTINELLIDA, megascleres four-rayed (Fig. 46, PI. 111).

Order II]—HEXACTINELLIDA, megascleres six-rayed.

1 _
1 A a
1
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AA ame a? sere ne ves Pe Ae SP RRP are ©
. af
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2 i
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+ irepsie a

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“ ay 4

f «4

Journ. of Mar. Zool. and Microscopy. Vol. I., Pl. III.

sixteen Ah elve ee MELLE NTE DOO ESD NAITO EAI

Jas. Hornell, Phot. ad Nat.

JERSEY BIOL. STN.

SILICKOUS SPONGES.

Journ. of Mar. Zool. and Microscopy. Vol. I., Pl. IV.

i

Pes:

Jas. Hornell, del ad Nat.

JERSEY BIOL. STN.

SPONGES, MONSTRILLA, AMPHIOXUS.

MICROSCOPICAL STUDIES... 39

We may tabulate the larger divisions of the Sponges thus :—
Phylum :—Porifera.

Branch A, Calcarea. Branch B, Non-Calcarea.
Family I.—Asconide. Class I.—(Skeleton siliceous) Sixicr-
se II.—Syconide. » SAS OUNGHEB
on hl Wenconids. Order 1I.—Monaxonida.
(Characterized respectively by the Canal “ _il.—Tetractinellida.
system indicated by the name). ““ Iil.—Hexactinellida.
Class II.—(Skeleton fibrous) CpRATOSA.
Class ITT.--(Skeleton none) MyxosponGizs

Puttmg aside in the present article any consideration of the
origin of the phylum as a whole, which is indeed bound up and
identical with that of the entirety of multicellular animals, it seems
most probable that the sponges arose independently by two main
limes from a primitive stock, rather than that the Non-Calcarea were
derived from the Calcarea or vice versd. Were the question limited
to the Calcarea, there would be little difficulty, for within the limits
of the division, forms are found ranging from the very simple Ascon
type, step by step up to the Sycon and thence to the complex Leucon
or Rhagon. The Non-Calcarea are on the other hand nearly all
of the Rhagon type, and were it not for the siliceous spicules in most,
might easily be derived from some form of the Calcarea. But the
nature of the spicules is a stumbling block. How derive a spicule
of flint (silica) from one of carbonate of lime? Can we imagine the
spicule forming cells to suddenly alter their selective power and
to seize upon silica instead of lime? It seems too much to ask.

As to the Ceratosa, this difficulty is wanting and it is not
improbable that their origim isdue to the renunciation of the
silica-secreting power in some ancestral siliceous sponge, while the
ancestors of the Myxospongis may have gone a step further and
have given up even the fibre forming power. But all is uncertainty
as yet. Even fossil records help us not at all, for the most highly
organized order, the Hexactinellida, are represented in our oldest
fossiliferous rocks, the Lower Cambrian.

All the figures of entire sponges on Plate III are reproductions
of photographs taken from living specimens, and show very clearly
the outward form of four very prominent species of our Siliceous
sponges—Halichondria and Clathria (Figs. 1 & 2) armed with rod-
hike spicules are typical forms of the Monaxonida; whilst the other
two, Tethya and Pachymatisma, are representatives of the great
group of the Tetractinellida. The third group, the Hexactinellida,
familiar to us in the lovely Venus’ flower basket (Huplectella), and
the strange Glass-rope sponge (Hyalonema) is not met with in
British waters. All belong to one or other variety of the Rhagon type
of canal system, and except in Tethya, the widely open mouths of the

40 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

oscula are plainly visible; situated in Halichondria at the apex
of tall crater-like prominences ; less marked in Clathria, where they
crown low rounded swellings, and in Pachymatisma, peculiar as
being collected mto special elevated areas, and there arranged in
serried, closely set rows. Details of histology must, for want of space,
remain over to a future article, and with this reservation, I will
now proceed to deal with the four species in question.

Halichondria panicea (Johnston), the Crumb of Bread, and also
the Coxcomb Sponge of Ellis, varies much in colour, ranging from
a greyish yellow to various shades of green. It is noteworthy that
the higher up the littoral and the more exposed to light, the greener
becomes this sponge. The yellow and ash coloured varieties are,
conversely, found in the lower zones of the littoral or where matted
curtains of fucus cause obscure shadowy light. In this sponge,
the entire duty of keeping open the canals devolves upon the
spicules, no fibrous tissue being present. The spicules (Fig. 1 a) are
all of one form, curved pointed rods, arranged in a well ordered
meshwork. Around the larger passages, the rows become much
strengthened. Sub-dermal cavities are greatly developed.

Clathria servata (Johnston), the Ophlitaspongia seriata of
Bowerbank, shows more complexity in its skeleton. A well developed
tough, square-meshed, horny network supports the sponge, beset,
urchin-fashion, with numerous stout smooth rodshaped spicules
pointed at one end only (smooth styh). The meshwork arrangement
of spicules seen in Halichondria is absent, and apparently the
horny skeleton is here used to keep open the canals—the spicules
ceasing such function and limiting their benefit to defence against
would-be enemies. A second and slender form of spicule, bow-shaped
(toxon) can also be made out.

Pachymatisma johnstonia (Bowerbank) grows to immense
proportions, and probably is the most massive of British sponges.
The one photographed was 6 inches long, weighing just half-a~pound.
Others we have had, have much exceeded this, e.g. one which is now
deposited in the Guernsey Museum, weighed when alive fully 6-lbs.,
and measured 12-ins. x 7—9-ins., and 4 inches high. In section,
this sponge shows many interesting points. An outer thick crust,
cortex or ectosome is greatly developed by the massing of immense
numbers of sterrasters—rounded and oval spicules thick set with
spines radiating in all directions (4 d). Similar spicules are spread
throughout the inner tissues of the sponge, the subcortical or
choanosome region, but if examined carefully, it will be seen that
these are much more sharply spinous than those of the cortex, which
appear worn and battered. Probably these spicules are formed in the
choanosome, and then pass outwards to accumulate in the cortex as a

MICROSCOPICAL STUDIES. 41

dense stony defensive layer. Other minute spicules (4 e — 4 h) are
found scattered through the tissues. As to the larger spicules, the
megascleres, the principal or four-axial ones peculiar to the order, are
here disposed as a supporting scaffolding beneath the cortex. The
form they take (Fig. 4 6) is known as the orthotrizne. Others of
simple structure (4 a) are located in the inner tissues.

The water of circulation enters through sieve plates into large
subdermal chambers, partitioned into two by a strong sphincter
muscle, able thus to close the opening on necessity. From the
inner chamber proceed the incurrent canals feeding the ciliated
chambers.

Tethya lyncuriwm (Johnston) is in many respects a remark-
able sponge. In appearance, it simulates perfectly a miniature
tangerine orange in colour and in shape. Extremely spicular and
furnished with a cortex—a true rind—as well developed as is that
of Pachymatisma, no pores or oscula can be made out by the naked
eye when the sponge is out of water, but im life in its native element,
the oscula seem to be collected upon a slightly papillate prominence
near the apex. Large canals are very sparse and it is at first difficult
to believe this sponge to possess a complicated canal system as it
undoubtedly does. The megascleres are strangely not four rayed
as we should expect, but are long slender rods (3 e—d) gathered
into great radiated bundles, quite obvious to the naked eye in a
hand section (8 b). Microscleres, in the form of beautiful starry
bodies, abound (8f & 39). As regards ciliated chambers, I have to
confess I have never seen any in either Pachymatisma or Tethya.
But this is not to be wondered at perhaps, as the size of even the
largest ciliated cells of any siliceous sponge is very small compared
with that of those of the calcareous species.

EXPLANATION OF PLATE III, Fic. 1-4 & Pu. IV, Fies. 1-8.
‘Sponge anatomy, &e.
Plate III, Fig. 1. Halichondria panicea, x 2; a. megasclere.

Fig. 2. Clathria seriata, x 2; a, megasclere ; 6, micosclere (toxon).

Fig. 8. Tethya lyncurivum ; a, another (smoother) specimen ; },
same split open to show cortex and radiating spicule
bundles; all x 2; ¢—e, megascleres; f & g, mi-
croscleres.

Fig. 4. Pachymatisma johnstonia x2; a & 6, megascleres ;
c & d, sterrasters; f & h, other microscleres.

42 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

Plate IV, Fig. 1—8. Diagrams of the types of Canal System.
f. 1. Ascon; f. 2. Chambered Ascon; f. 3 & f. 4. Sycon ;
f. 5. simplest possible Rhagon ; f. 6. Eurypylous Rhagon ;
f. 7. Leucon or Aphodal Rhagon ; f. 8. Diplodal Rhagon.
All these are shown in vertical section, saving Fig. 4
which shows transverse section. In the Rhagon diagrams,
the white portion represents the greatly developed meso-
derm. ‘The shaded portion denotes where ciliated cells
occur. Arrows denote the direction of the water currents.

Stupy V.—A CONTRIBUTION TO OUR KNOWLEDGE OF THE
CoPpEPOD MONSTRILLA ANGLICA.

This species is for many reasons extremely interesting. A single
specimen, a male, was captured in 1857 by Sir John Lubbock (1) at
Weymouth, and at the publication of the concluding volume of
Prof. Brady’s fine monograph on the British Copepoda (2) in 1880,
no further record had been made and the original specimen had been
lost. Just about this time the record was resumed by the capture off
Jersey, of a few specimens by Mr. J. Sinel, who however did not
identify his interesting find till the publication, by Mr. I. C. Thompson,
of the description of a specimen of the same animal taken off Anglesey
in the autumn of 1887. Mr. Thompson at first believing the animal
to be new to’ science, named it Cymbasoma herdmani (3) but later
on, having more material to examine, he recognized his animal to be
of the same species as Lubbock’s. Since 1880, Monsirilla anglica
has appeared pretty regularly every year off Jersey during Aug. and
Sept., in sparing numbers. Mr. Thompson has also recorded a second
specimen from the Irish sea (5), and another from off Malta, while
one or two more have been taken on the south coast of England.
Apparently then, here in Jersey, we have been the most successful in
obtaining this rare animal. Indeed of late years we have been specially
so, for out of a small number of tow-nettings taken in Aug. and Sept.
of the last two years, we have picked out nearly 80 specimens.

Normal Copepoda may be defined as minute crustaceans of
simple organization, having an elongated body clearly divided into
numerous rings or somites, and without the shield-like shell or
carapace that covers the anterior part of the body being double or
bivalve, having an anterior pair of antenne or feelers (properly
antennules); a posterior parr (the true antenne); 3 pairs of
mouth organs (1 pair mandibles, 1 pair maaxille, and 2 pairs
of maxillipedes ), and five pairs of two-branched, biramous, swimming
feet attached to the anterior part of the body or cephalothorax. The
hinder end of the body consists of an abdomen of 5 somites bearing
no organs and terminated by a forked tail.

ee

MICROSCOPICAL STUDIES. 43

With such definition Monstrilla closely agrees if the italicized
part be omitted. Every vestige of the usually well developed and
complicated mouth organs is absent ; the posterior antennee have shared
a like fate, and further, no trace of alimentary canal can be made
out, though a very short tubular proboscis is apparent. This however
leads nowhere, and I am inclined to hazard the suggestion that these
animals may live during the greater part of life as suctorial parasites
upon or within some larger animal, but that at breeding time (Aug.
and Sept.) they leave their hosts and seek for mates, free-swimming
in the surface waters of the sea. Certainly many species of copepoda
do live as parasites, e.g. the whole family of Notodelphyidee affect some
or other of the simple Ascidians, while others live within the cockle,
pecten (6) and other shell-fish. Regarding the assumption that
Monstrilla forsakes the host at the breeding time, and that stomach
and intestine become absorbed coincidently, such would not be
without parallel among other animals. Thus those small free-
swimming worms, the Syllide, forsake their homes among the
corallines as the time for reproduction approaches, and are found
among the surface life of the sea with alimentary canal reduced to a
mere cord or else entirely atrophied, and the cavity of the body
wholly filled by masses of ova or of sperm. Reference to PI. iv,
Fig. 9, will show how the ova in Monstrilla is similarly disposed.
Mr. I. ©. Thompson has indeed (5) considered and condemned
the view that this animal may be a sucking parasite—but apparently |
he has overlooked the probability now suggested, of its regularly
abandoning such habit and altering its anatomy at the breeding
season. He adduced the fact that all specimens of Monstrilla have
been recorded as free-swimmers near the surface—but considering
that a copepod, common in, and peculiar to the cockle, was only
discovered in 1892, there is plenty of chance of this supposed
parasitic habitat of Monstrilla to have been overlooked. Hence
I cannot without positive evidence agree with Bourne (7) in the
possibility that “the adult may be preceded by a predaceous larva
supplied with mouth parts and an alimentary tract, which, after a
succession of rapid ecdyses, develops into the mature sexual form,
whose only function is that of reproduction.” But we have no record
of such a larva having been seen—and as such would be less easily
overlooked than would a parasitic adult in some perhaps obscure host,
I think the suggestion I mention is the more probable. A great deal
of work has yet to be done ere the parasitic copepoda are even fairly
well known, and I would therefore draw the attention of workers
to what assuredly is a promising field for research.

The few appendages possessed by Monstrilla are all exceedingly
interesting when viewed under a high power. Thus if we examine

44, JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

the antennz of the male, we will find each to be five jointed, and
furnished with a most curious variety of spikes and sensory hairs:
First there are numerous short stiff spines, next a few much longer
ones with a row of regular dots along each margin. Some of these
hairs are equal in length to half that of the antenna itself. Of about
equal length are three strange much branched slender hairs set
around the apex of the terminal joint. Into these hairs, branch
nerves can readily be traced. At the apex of the last joint is a claw-
like spine. These spines and hairs are very definite in position and
number, thus the Ist joint bears 1 short spine,
the 2nd has 5 spines and 1 long haar,
“ 8rd “ 1 spine and 2 long hairs,
“ 4th “ about 5 spines and 1 long hair, while
“ 5th “ 1 stout claw spine, 2 slender ones, 3
branched hairs, 1 long straight hair and a
short slight apical thread-like process.
Between the 4th and 5th joints is a strange hinge arrangement,
peculiar to male copepods, and of use in holding on to the female.

The antenne of the latter are shorter and less deeply jointed
than those of the male; the ratio being as 8 to 11. The 4th and
5th jomts are practically fused into one, so that the antenna seems
to consist of 4 joints only. The spinous hairs are more strongly
marked in the female, while the branched and the long hairs are
less developed. Apparently then, these being sensory, it falls to
the male to search for his mate. In arrangement, the hairs, &c.,
are much the same in both sexes—except that in the female the
part that answers to the 4th joint bears 5 spines and 8 long hairs,
while what represents the 5th, in addition to having a stout apical
claw spine has two others equally well developed and which are
equivalent to the two slender spmes in the male. It has been
said that the claw spine of the male is for use in seizing the
female but, seeing that the latter is even better equipped, it seems
to me more likely that these are primarily of use in anchoring as
parasites to some host.

The cepalothorax to which the swimming feet are attached,
is, in its front part, covered by a great shield, the carapace. On
the under side, at the hinder edge of the region thus marked
out, is inserted the first pair of feet. Behind the carapace are four
distinctly marked off body rings, each bearing in the female a pair
of feet on the under side. In the male the fifth pair of feet are
suppressed. In structure the first 4 pair of feet are very much
alike. The fundamental plan of the typical crustacean foot can be
traced clearly. A stout basal part of two stout joints articulating
to the body represents the protopodite, To the joint away

MICROSCOPICAL STUDIES. Ad

from the body are joined two branch limbs, one directed inwards,
the other outwards, respectively endopodite and exopodite. Each
again is divided into 3 short joints, bearing sete or stout hairs
definitely placed (PI. iv, Fig. 12). The Ist pair differs from the
others in possessing one hair less on the distal joint of the exopodite.
All the setz of the feet are finely plumose. The fifth pair of feet,
present only in the female, is very different, as each foot consists —
merely of two short weak joints, bearing at the termination a couple
of slender hairs.

The abdomen consists of 4 joints (Fig. 10, 1, 2,3 & 4), ending in
a forked tail. Each fork bears 1 slender and 5 stout bristles in
the position shown in Fig. 11. Lubbock erred in writing “ upon the
fourth candal seta (counting from the outside) is another, rather
smaller than the other five.” In reality it arises from the tail fork
in the same way as its fellows, but bemg very slender, a mistake
is very liable to occur. Mr. I. C. Thompson has apparently over-
looked this slight hair in his diagnosis of the species as he says
“5 sete to each furcal segment ” (6).

Muscular System.—By selective staining, I have been fortunate
in being able to make out very clearly the principal arrangements
of the muscles. A glance at Figs. 10 and 11 will show how immensely
powerful this tiny creature (female 3 mm. long; male 2:25 mm.) is in
proportion to its size. This is apparently against the idea of the
generally parasitic life of this animal, for such life in general leads to
partial atrophy of the muscles. Still it does not dispose of the
suggestion—there may be compensating causes. _

To return. The largest muscles are found within the carapace,
lying longitudinally ; four pairs arranged as in Figs. 10 and 11. The
two upper or dorsal pairs are used in straightening or extending
the body, extensors; the other two pairs for bending or flexing,
a. flexors. Each of the following body rings or segments possesses
but one pair of extensors and the same number of flexors, modified
however in the abdomen by the extensors of the first and second
segments, and both the extensors and the flexors of the third and
fourth being respectively wholly or in great part coalesced. Thus
these segments lose more or less their independence of action, the
first and second acting in concert in extension, the third and fourth
in all movements. To understand well the action of these body
muscles we must remember that the axis of movement between
adjoining body rings lies transversely across the body a little above
the articulation of the feet, so it is obvious that a pull below such
axis, will bring the rings together on the under side, producing
flexion; conversely, if above, the opposite, i.e. straightening will

ss
,

46 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

be produced. Hold a coin between finger and thumb, pull on the
uppermost point of the edge and the movement that produces
extension in crustaceans, is simulated; if the lowermost edge be
pulled, then flexion is imitated. The anterior end of all these muscles
is attached well forward to the inside of the chitonous shell that
forms the protective skeleton in these animals; the hinder end being

‘inserted on the front edge of the body ring next following, and which
is governed in action by the muscle so placed.

The swimming feet are each governed in their larger movements
by two great fan-shaped muscles which pass upwards from the thigh
joint along the sides of the body. The smaller movements are
co-ordinated by a very complex series of small muscles which space
forbids the enumeration of. The antennz are each governed by two
strong muscles passing backwards close to the eyes. In both sexes
the muscular development of the antenne is great, particularly in
the male, and is of great assistance to the animal in swimming,
being, in this sex, virtually equivalent to the addition of another pair
of swimming legs.

Sense Organs.—These seem practically limited to eyes and
sensory hairs. The former are well developed, three in number, each
possessing a large crystalline lens. They lhe somewhat in triangular
fashion, two paired ones on the upper surface of the head between
the bases of the antenne, and a third, the unpaired one, bemg
beneath these on the under side of the head. The structure is
essentially that of a convex glassy lens set in a mass of pigment and
connected by a stout nerve with the brain.

It is interesting to notice that the paired eyes look sideways,
while the unpaired one looks downwards and forwards, just the
best possible optical arrangement for the animal when it betakes
itself to free life at the surface of the sea. To pelagic animals there
is no above. Their world lies around and beneath, and there alone do
they require to cast inquiring glances, if indeed their modest optical
equipment will so permit me to phrase it.

In the females full of ova, the eyes are frequently much reduced
and apparently more or less absorbed and functionless.

As to sensory hairs, there are apparently two kinds, one having
a much branched form (Fig. 10, a), the other straight and un-
branched (b). It may be that @ is olfactory and b tactile, but this
rests entirely upon supposition.

Respiration.—No organs adapted to this end. The general
surface of the body seems to function.

Reproduction.—The sexes are always separate; the difference
expressing itself plainly in the outward form. The male is smaller
(2°25 mm.) than the female (8 mm.); he has more powerful antennze

MICROSCOPICAL STUDIES. AT

(ratio 11 to 8); the hinge between the 4th and terminal joints of
his antenne is absent in those of the female; he is without the
rudimentary fifth pair of swimming feet present in the female, and
the sexual orifices which open in both sexes on the under side of the
Ist abdominal segment, are in the male situated on stout low
prominences (Fig. 10, 7); in the female when mature, these are
produced into long tubes reaching backwards considerably beyond the
ends of the caudal bristles. Internally both ovaries and testes lie as
two great paired glands in the cephalothorax. Both sexes have in
this species two distinct efferent ducts whereby the genital products
are passed downwards and obtain egress at the openings already
mentioned. The function of the long tubular genital processes of
the female (c) is probably to give attachment to the ova after
being extruded, as Mr. I. C. Thompson has observed ova adherent
to them in an allied species (4).
REFERENCES :—
1. Lupgock, Sir Jouwn.—Ann. & Mag. Nat. Hrst., Vol. xx, 2nd
Series, 1857.

2), Brady, Prof.G.S. —A Monograph of Br. Copepoda (Ray
Soc.), Vol. 111, 1880.

3. Thompson, I. C. —Second Rep. on Copepoda of L’pool Bay
(Trans. Biol. Soc. L’pool, Vol. Il), 1887.
4. e # —Copepoda of Madeira (Journ. Linn. Soe.
Zocl., Vol. xx), 1887.
5. : —Monstrilla & the Cymbasomatide (Trans.
Biol. Soc. [’pool, Vol. iv), 1890.
6. G ‘ —Revised Rep.on Copepoda of L’pool Bay
(Trans. Biol. Soc. I’pool, Vol. vit), 1893.
7. Bourne, G. C. —WNotes on the Genus Monstrilla (Quart.

Journ. of Micro. Sc.), Feb. 1890.

EXPLANATION OF PLATE IV, Fics. 9—12.
Monstrilla anglica (Lubbock).

Fig. 9. Side view of a female full of ova (size 3 mm.), am antennary
muscles, ¢ eye, o proboscis, c genital tubes. (Mote—No
definite articulation should be shown between the fourth
and terminal jomts of the antenne. Such is shown
here by a slip in drawing.

Fig. 10 & 11. Lateral and dorsal view of a male (size 2:25 mm.),
a branched sensory hairs, 6 straight tactile (?) hairs,
m & mi, the extensors muscles of the segment next
behind the carapace, mi & mi¥ flexor muscles of same,
1, 2, 3 & 4 abdominal segments, f genital prominence,
d the 6th or slight seta of the caudal fork.

Fig. 12. View from behind, of the third pair of swimming feet.

4S JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

VI. THE Main Facts CONCERNING THE LANCELET (AMPHIOXUS
LANCEOLATUS).

Few animals are cosmopolitan. Changes of climate, food, and
habits, brought about by life in other latitudes, alter, directly or
indirectly, sooner or later, some features of the body, and the migrant
becomes a new variety, and even in course of time may have this
variation so indelibly impressed upon it, as to constitute a new
species. Hven migrant civilised man, with all his special advantages
of constant inter-communication with his original stock, is affected
appreciably in comparatively a short time. The American—our
Brother Jonathan-—has not our features, but bears a physical trade-
mark solely his own; our cousin, too, i New Zealand—a really
nearer relative than he from the U. S. A.—is developing “ points”
alien to ours. Naturally however, the land is less likely to present
cosmopolitan types than the sea. Under the waves vicissitudes of
climate are reduced toa minimum. But even there, we but seldom
find a species stable over widely extended areas; those known to be
world-wide may practically be counted on the fingers.

Thence, when we find that perhaps the most curious of living
animals, the strange Lancelet, most lowly among the vertebrates, is
found without appreciable change of form or structure in the seas of
Europe (around Britain and in the Mediterranean), along the North
American coast, in the West Indies, Brazil, Peru, Tasmania, Australia,
and Borneo, we seize one of the many noteworthy facts concerning
this animal.

Spread thus universally, Amphioxus lanceolatus is not only the
sole species in its genus, but also the only representative of the
family, and even of the group to which it belongs. Curiously enough,
the first example known, was caught off Cornwall, and passed into
the possession of the early Russian naturalist Pallas, who indeed saw
so little affinity with the vertebrata, that he described it (1774) as a
slug, Limax lanceolatus. Some fifty years passed ere we have note
of a second specimen being caught (1831). This again was taken on
our English coast, at Polperro, Cornwall. It was well described by
Yarrell, who bestowed upon it the name we are now so familiar with,
Amphioxus lanceolatus. Yarrell recognised its relationship better,
and placed it at the bottom of the list of fishes, where it has ever
since remained.

The growth of the systematic study of marine life has of late
years shown Amphioxus to be both widely spread and frequently
numerous, so that now it may aspire to join the select circle of

martyrs to science, already adorned with the names of the frog
and the dogfish.

MICROSCOPICAL STUDIES. 49

The anatomy and description of few animals are better known,
hence I have little or no excuse for occupying space with details here.
Any zoological text-book will provide such, as for example Marshall
and Hurst’s “ Practical Zoology,” which is specially commendable,
from its clearness and accuracy. I will therefore now give what
is itended as merely a running commentary upon the figures as
drawn on Plate IV.

External Characters.—In life, the Lancelet is a small, nearly
transparent fish-like animal, pointed at either end—of some two
to three inches in length. No scales are present, the body being
clothed in a thin transparent cuticle. Along the entire dorsal region,
and along the ventral from atrial pore to the end of the body, the
skin is raised into a fold or ridge best marked both dorsally and
ventrally in the part of the body posterior to the anus, and which we
may term the tail. The dorsal ridge of skin is strengthened, except
at the ends, by a row of cube-like compartments forming a supporting
skeleton, answering to the fin rays of true fishes. The ventral ridge
is strengthened by a similar skeleton between atrial pore and anus,
and this part is the ventral fin (vf); the fold running along the
dorsal and ventral sides of the tail being the caudal fin, while the
dorsal fold anterior to the tail constitutes the dorsal fin (d/.)

Alimentary Canal—The mouth is a large oval aperture
placed anteriorly on the ventral aspect, and bordered on either
side by a line of tentacles (bt). The mouth leads into an elongated
dilated chamber, the pharynx, which functions also as the organ of
respiration (ph). Its walls are supported on either side by a frame-
work of cartilaginous arches set obliquely, the gill arches (ga), along
which course the branchial blood-vessels. Between every two arches
is a long narrow perforation, the gill cleft. Through these openings,
the water, brought in through the mouth by the action of the cilia
that line the pharynx, is directed into a cavity all but surrounding
the pharyngeal tube. This, the Atrial Chamber, corresponds closely
to that of similar name in the Ascidians, and indeed, the respiratory
plan is altogether exactly conformable in the two animals. The
water passing into the atrial cavity from the pharynx is conveyed
out by an opening, the atrial pore (ap), situated at the front end
of the ventral fin. As in the Ascidians, an endostyle is present
in the ventral wall of the pharynx. It is however flattened in the
anterior part, but posteriorly it has the deeply grooved form charac-
teristic of Ascidians. The epibranchial groove found in Ascidians
is also well marked as a dorsal counterpart of the endostyle.
The pharynx leads into a straight intestine ending in an anal
opening (wa) placed on the left side of the ventral fin.

50 _ JOURNAL OF MARINE ZOOLOGY AND. MICROSCOPY.

Immediately above the alimentary canal is a tough elastic rod,
the Notochord (nt), reaching from end to end of the body. Above
this again, lies the Spinal Cord, a cylinder having slightly less
diameter, marked along the under side by black pigment cells.
No brain is apparent, but the more anterior part is slightly thicker
than posteriorly. Branching nerves are given off at intervals to
the various organs.

Sense Organs are rudimentary; a pigmented patch at anterior
end of the spinal cord, serves as “eye,” while a ciliated pit at the
same point may be olfactory in function.

The Muscular System is well developed and enwraps the various
organs as in a sheath. Its elements are composed of striated fibres,
arranged principally in peculiar < shaped bundles or myotomes
numbering 61—62 on either ‘side of the body. On the ventral
surface are subsidiary muscles running transversely whose function
is, by contraction, to expel water from the atrial cavity.

Blood System.—No definite heart is present. Impure blood
from all parts of the body is collected into a ventral vessel, the
cardiac aorta, which by the contractility of its walls is able to propel
this blood into paired vessels, aortic arches, that pass along each
alternate (primary) arch. The blood, purified in these vessels by
intimate exposure to the water passing through the gill slits, is
emptied into a right or left dorsal aorta according as it comes from
right or left side of the pharynx. The right and left dorsal aortze
unite to form, at the hinder end of the pharynx, a single vessel which
passes backwards on the dorsal side of the intestine. From the
dorsal aortee the purified blood is distributed to the organs of the body.

Reproductive Organs.—The sexes are separate—ovaries and
testes have the same outward appearance, that of two rows of
enlargements along the body-wall, external to the atrial cavity and
parallel with the pharynx, a row on either side of the body. The
products escape by rupture of the atrial wall, into the atrial cavity
and escape by the atrial pore, or it may be by the mouth, by passing
_through the gill clefts.

Want on Internal Symmetry.—It is a remarkable fact about
Amphioxus, that the internal organs do not show bilateral symmetry,
that is, are not arranged in balanced pairs. Thus any particular gill
cleft on one side is opposite a gill arch on the other side instead
of opposite another cleft. The aortic arches necessary partake also
of this asymmetry. The muscle segments or myotomes, nearly all
the nerves arising from the spinal cord, and the reproductive glands
are also alternate on the two sides of the body. ‘The liver too is
asymmetric, being turned to the right side, while the anus opens
on the left side. *

MICROSCOPICAL STUDIES. 51

Development of Gill Arches.—These are of two kinds; half
are forked at the ventral ends, others which alternate are unsplit.
The cleft in front of, and that behind each unsplit rod originally
formed together a single opening which, by secondary growth
downwards of a portion of the wall, become divided into two in the
manner shown in Fig. 16, Plate IV. The down-growing rods may
be therefore termed secondary arches, the others primary. In adult
individuals connecting bars cross the clefts so as to joi more
intimately the primary and secondary arches, an arrangement
reminding us of that in the Ascidians.

A comparison of Amphioxus with a typical Ascidian is extremely
interesting and suggests such a closeness of relationship that were
it not for the emphatic developement of a central skeleton, there
would be more reason in classing it as a highly developed free-
swimming Ascidian, than as a little developed ancestral fish.

‘The points of similarity are well brought out by glancing at the
comparative diagrams of the two, shown in figs. 14 and 15. The
section shown in both figures is transverse. In the Ascidian, the
section is just posterior to the mouth and through the nerve ganglion
that serves as brain. That of Amphioxus is through the pharynx.
Examination shows how, except in minor details of relative thick-
ness and arrangement of the tissues, the fundamental similarity
(homology) is absolute, saving for the presence in the lancelet of a
central skeleton, or notochord (nt). In both the body is encased
in a more or less structureless cuticle. Within this is a ring of
muscular fibres, and more or less sunk in this muscular layer is the
central nerve-mass (7.) Suspended from the muscular band at a
point just beneath the nerve centre, is a perforated pharyngeal tube
shown in figs. 14 and 15, by an interrupted line (ga.) intended to
represent the sections of alternate gill arches and gill clefts. Top
and bottom of this pharyngeal tube are two grooves, respectively
the epibranchial groove and the endostyle.

The minor differences as seen in such a section are :—In the
Ascidian the cuticle is immensely thickened to form a protective
test; but the muscular hoop is infinitely less developed than in the
Lancelet, due to the want of much muscular effort in the sedentary
~ life led by the former. In the Lancelet again, the pharyngeal tube
is only attached dorsally. In the Ascidian, it is, at the points shown,
attached both dorsally and ventrally.

In both animals the mechanism of respiration and feeding is
“alike; the muscular arrangements are strictly comparable ; the
reproductive products are in both expelled from the genital glands
‘Into the atrium and leave the parent by either the atrial pore or

52 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

' mouth. In both is the same lowly development of sense organs, and
-want of any defined cephalic or head region.

The points of divergence are essentially the presence in the
‘Lancelet, of a notochord, of an elongated central nerve-mass, and of
a higher type of blood system.

Finally it is noteworthy that a series of minute tubules, probably
excretory, open into the upper portion of the atrial cavity on either
side of the pharynx. There can be but little doubt that these
represent the paired excretory tubules (nephridia), so characteristic
of the worms. Hence, as no kidneys of any vertebrate pattern are
present, the Lancelet exhibits in the structure of its renal organs,
the most unmistakable of its many plebeian characteristics.

EXPLANATION OF Fics. 13—16, PLATE IV.
Amphioxus lanceolatus (Yarrell).

Fig. 13. View of a young specimen ;%,-in. long ; from the left side.

Fig. 14. Diagram ofa transverse sebtion of same through pharyngeal
region.

Fig. 15. Diagram of a transverse section through the anterior end
of the body of a typical Ascidian, e.g. A. mentula.

Fig. 16. Diagrams showing the mode of formation of a double gill
slit from a single.

Lettermg the same in all figures, viz. :—a p. atrial pore; a. anus;
bt. buccal tentacles; c. cuticle; df. dorsal fin; e. eye; end. endostyle ;
ep g. epibranchial groove ; ga. gill arches; 1%. intestine ; J. liver ;
m. muscles; 7. nerve system ; “nt. notochord ; ph. pharynx : p ¢.
pigment cells; spc. spinal cord ; v a ventral fin.

A PROGRAMME FOR THE EASTER HOLIDAYS.

Those who look forward to Easter as a short interval of relaxation from business
_ routine, when perhaps some profitable shore collecting may be accomplished, will
note with pleasure that on Good Friday (March 23rd), there occurs one of the highest
Spring tides of the year. On the Jersey coast, the vertical rise and fall is 39-ft, 2-in,
The Laminarian zone with its varied treasures will be largely uncovered, and any
naturalists paying our island a visit will be richly rewarded. On the Friday, we
intend to visit by boat the outlying reefs and caverns; on the Saturday, there will
be extensive shore-collecting during the day and at night a moonlight tow-netting
among the islets of the bay in front of the Station. Inclusive charge will be 12/6,
with use of laboratory compartment, reagents, utensils, &c. We shall be pleased
to answer any enquiries. Tur Directors, JERSEY BIOLOGICAL STATION. (See also
page 3 of cover).

TO CORRESPONDENTS.

All communications for the Eprror to be addressed to the
BIOLOGICAL STATION, JERSEY.

Original notes on Marine Life are invited; while technically
correct, they must however be written in an interesting style.

Advertisements to be sent to the same address.

‘IOOTA WHINY JO UOTIAOG JO MOTA AOU] ‘UOTYIS [VoIsolOIg eUTaB AessLOL

et

ie a
Sieh

‘Qd01ds1}UuOdy “JT ‘1OA Adodsodd PUB *[00Z ‘ABW JO “uaNor

Che Hownal of Stlayine Soologp
and Silicroseopn :

A PLAINLY WORDED BIOLOGICAL QUARTERLY.

You. I. No. 3. MAY, 1894.

OUR PROGRESS AND OUR PROGRAMME.

OW that six months have elapsed from the inception of our
venture, we are in a fairly good position to assess the measure
of success that has rewarded our efforts. In the number of subscribers
gained, our expectations have been immensely surpassed, and we are
proud to say that our little Journal penetrates everywhere in Britain
where Zoology and Microscopy find votaries. In size, the Journal
has expanded from the 16 to 24 pp. promised in the prospectus, into
a minimum of 28 pp. which too we shall expand to 32 or more, if
each of our subscribers will but help us by prevailing upon a friend
to remit us the sum of 3/4 as one year’s subscription. And in this
connection we may point out that increase of size has necessitated
the raising of the price to 10d., including too, the back numbers—
but then we make no additional charge for postage on any numbers
forwarded from the Jersey office. |
We wish also to bring before the notice of our friends, the fact
that we have further aims than simply to produce a useful scientific
magazine. Through the medium of our Marine Biological Station at
Jersey, we have certain public duties to perform, in the facilitating
of the practical study on the spot, of marine life. Our laboratories,
established last year, have had considerable measure of support. The
following, among others, have rented compartments for longer or
shorter periods, or have had instruction in the preservation of marine
animals, viz :—
Miss Kva Hoorrr, London,
Miss Warp, Ladies’ College, Jersey.
Mr. F. Borrow, Medical School, St, Bartholomew’s Hospital.
Mr. H. Burrows, Medical School, St. Bartholomew’s Hospital.
Mr. E. 8. GoopricH, Dept. of Comp. Anatomy, Oxford.

My. D. Houston, Director of Biological Instruction, Hssex County Council,

Mr. R. Pautson, Sec. Toynbee Hall Nat. Hist. Soc. and several members of same
Society.

Mr. W. G. RipEwoop, Br. Museum (Nat. History),

Dr. HK. Maretr Tims, Medical School, Westminster Hospital.
Mr. H. H. L. Scuwarz, Royal College of Science, London.
Mr. Hy. ScHERREN, F.Z.S., London.

Mr. W. H. Untuansg, Birkbeck Institute, London.

Several of the above have followed out a wide course of dis-
section with the view to qualifying in the higher exams in Zoology

54 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

of the London B.Se. syllabus, and it is most satisfactory to us
that all have expressed themselves extremely gratified with the
accommodation and material provided for their work. In these cases
a full supply of all the living types required, is provided free to all
renters of laboratory compartments, and as the rent of these, inclusive
of the full use of reagents, microtomes, dissecting dishes, library, &c.,
varies between the modest sums of 7/6 and 12/6 per week, we
scarcely require to emphasize the great boon our Station is to those
who elect to make use of it. Undoubtedly the facilities we offer, are
more extensive and lower priced than any to be had elsewhere in
this country. We have, at the very doors, a fauna immensely
richer and more valuable than that available to any other British
Zoological Station. .

A vital necessity to such an establishment as ours is a good
reference library, kept well up to date. And this keeping up to date
is a weak point with us. Our means—unsupplemented by the
Government and local grants so freely given to marine stations well
nigh everywhere else but in this belated island of Jersey—are quite
inadequate to this strain, and we appeal earnestly to friends to help
us in this respect either by the gift of books or pamphlets, or by
donations to the library fund. Several gentlemen have been ex-
tremely kind in this way. Thus among others—to all of whom we
beg to tender our most sincere thanks—Mr. W. Hatchett Jackson
has, within the last few days, sent his extremely valuable revision of
Prof. Rolleston’s “Forms of Animal Life”; while Mr. Theo. T. Groom
has contributed his monograph “On the Early Development of
Cirripedia,” and the Smithsonian Institution contribute their “ Proc.
of the U.S. Nat. Museum.” To the Editors of “The Journal of
Malacology,” “The Naturalist,’ “The British Naturalist,” “Knowledge,”
“Science Gossip,’ “ Neptunia,” and several others whom space pre-
vents naming, we have also to return thanks for the favour of
exchanges.

As to the future—we have pleasure in announcing that Mr. Theo.
T. Groom, our foremost British authority on the Cirripedes, will
contribute to our next number a very interesting article of original
observations upon the development of the Barnacle (Balanus),
while Mr. Ernest H. L. Schwarz will be responsible for an equally
important paper on the ancestry of the Octopods, and the close rela-
tionship of the fossil Ammonites with this group. “A Naturalist’s
Year” will, it is hoped, also be commenced either in this or the next
following issue. In this will be recorded the breeding times, and
‘occurrence of notable marine animals upon the Jersey coast, with
such items of investing interest as may from time to time crop up.

CONTRIBUTIONS TO THE STUDY OF VARIATION.

BY JAMES HORNELL.

SEriES IL—a. Sexual colour divergence in Labrus mixtus.
b. Duplication and origin of the operculum im Serpula.
e. Anastomosing of muscle bands in Salpa.

I. SEXUAL COLOUR DIVERGENCE IN LABRUS MIXTUS.

HE Labrus mixtus of Linneus, and the LZ. trimaculatus of

Pennant, are by no means rare on the Jersey coast. Yearly

a fair number are caught during the warmer months, especially in

the more deeply sunk lobster pots. Apparently they do not come so
close inshore as the other Wrasses.

These fishes differ so immensely in colour that they are recorded
as different species, while at the same time, the fact that they agree
closely in size, habits, contour, and anatomy, has given rise to the
strong suspicion that they, in reality, represent the different sexes of
the same animal. Dr. Giinther, among others, has formulated this
opinion, and undoubtedly it is correct, for the sole divergence—
colour—I have recently noticed to vary in a manner calculated to
remove all doubt as to such relationship being the true explanation.

Than L. miatus, called here “ coucou ” universally by the native
fishermen, there is probably no more gorgeously bedecked British
fish. So bizarre and gaudy is it indeed, that the taxidermist, who,
with scrupulous fidelity, reproduces the crude and glaring tints in
their full brightness, is apt to have his work eyed askance, and to
receive as scant courtesy as did the traveller’s tales of Bruce on his
return from that memorable pioneer Abysinnian journey. Bright
orange red predominates, streaked by some three longitudinal vivid
blue bands; several blue or purplish markings and blotchings adorn
the head, in which glistens—a very jewel—the bright crimson eye.
The large dorsal fin is orange and red in varying patterns—some-
times a margin of blue specially strong at the hinder end—more
rarely the anterior part blue, the hinder orange. Then the tail is a
marvel of colour, the blue usually disposed as a sharply defined
edging.

56 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

The so-called, L. trumaculatus, called here “ Le Roi,” is normally
of a bright vermilion orange, with from three to five dark blackish
patches along the back, close to, and sometimes even encroaching
upon the dorsal fin. The most well marked spots are usually just at
the hinder end of this fin.

Now the evidence I have to offer is briefly stated thus :—These
fishes being brightly coloured, we used our best endeavours to procure
a good number for the aquarium tanks of the Station, and as they
are extremely resentful of handling, bemg usually half dead, spite of
all care, when brought up from the fishing boats, we, unfortunately, —
had an opportunity of examining quite a considerable number ere we
succeeded in stocking the tanks. Of such as were brought wp, most
of the L. trumaculatus were of the colouring noted above; two,
however, showed unmistakeable signs of the LZ. miaxtus relationship.
Thus one showed dark markings on the head in just the position of
_the blue streaks of LZ. mixtus, while similar dark bands were along
the sides of the body, and the tail, too, showed a faint but decided
blue border. The other specimen was almost without the charac-
teristic black spots, and showed besides, faint blue marking on both
tail and dorsal fin. -

On the other hand, a very fine example of the blue striped, or
LL. miaxtus, type, which we were successful in keeping for several
months, gradually faded as November ran its course. From being
the gay coloured Cuckoo fish, its bright blue and purple streaks and
bands slowly paled till in parts they were all but lost. At the same
time two distinct black patches appeared on the back just m front of
the tail fin. One was situated a little behind the dorsal fin, the
other a little in front and spreading slightly on to the membrane of
the fin. Trace too of a third spot could be made out about an
inch in front of the last mentioned.

It is difficult without the help of coloured plates to show the
full cogency of these abnormal colourings, but what I have stated
will suffice to finally prove the good grounds of Dr. Giinther’s
surmise—a surmise, which in common justice, I must however say,
had been years ago anticipated by the Jersey fishermen, who have
been, from time immemorial, in the habit of applying the term
“coucou ” indiscriminately to both the LZ. mixtus and the L. tri-
maculatus type; the term “Ze Roi” (ut swp.) applied to the former,
being only used by the more particular of the fishers.

We may therefore count these two colours as representing res-
pectively the male and the female of one species—for which the
name L. miatus, L. will be the more appropriate cognomen to retain.

Dissection has also shown the sexual organs to conform to this
view.

CONTRIBUTIONS TO THE STUDY OF VARIATION. Lay

IJ. DUPLICATION AND ORIGIN OF THE OPERCULUM IN SERPULA.

It is of frequent observation that certain animals are charac-
terised by more or less mutability, either as entire organisms or else
in some particular organ. Such mutable species are, however, greatly
in the minority—the vast majority being so remarkably stable in all
save trivial degrees, as really to be cause for wonderment, considering
the diversity of environment that most species must encounter in
life’s struggle. Accordingly the forms exhibitmg marked mutability,
are of the greater interest. These variations fall naturally into three
categories; @, where the mutation is due to an atavistic cause, VE.
recalling some phase in the past history of the race to which the
animal belongs; b, where it is spontaneous or original, and usually
limited either to one individual or to a few nearly related ones—a
variation often pathological ; lastly, c, where the change is due
directly to altered environment and altered habits—a change which
will probably become fixed, and therefore producing a distinct and
permanent variety—liable to become sufficiently stable to constitute
finally a new species.

The following instances fall, I believe, to be explained by the
first of these causes :—

I. Serpula.* Having recently occasion to examine a large
number of that most beautiful Serpulid, S. (Hydroides) pectinata,
Philippi, to my surprise, I found 25 / of the examples—which be it
noted were not all from the same cluster of tubes or vermidom, but
from several—affected in more or less degree with abnormality in the
antenna.t The proportion was very constant; out of two large
batches, the variation was not more than 1°6 Ve viz., 8 abnormal out
of 32, and 14 out of 60. Others I have examined since, have shown
a like proportion.

In the present note, the two antenne are distinguished for con-
venience under the terms respectively of antenna and of operculum;
the former term being applied to the process which, while homologous
to the long filament modified to form an operculum, is normal short

* For those unacquainted with the Serpuline, I may here explain that they are
those tube-building worms, whose sinuous limy tubes are frequently seen upon old
and sea-worn shells—oysters, scallops and the like. Attached to the head in these
animals, are two half circlets of delicate bipinnate plumes, useful as breathing (gills)
and touch organs, while close to the first gill-filament on either side on the dorsal
aspect is a non-pinnate organ—on one side, long stalked and stopper-like, the oper-
culum ; on the other, short and weak and nearly aborted. Serpulids have the power

of withdrawing entirely within their tubes, and of stopping the entrance with the
plug-like operculum.

+ Ladopt here Quatrefages’ nomenclature, viz., call the appendages that belong
to the prostomium, antennsz; and reserve the term tentacles for the appendages
of the peristomium. (Peristomium—=mouth somite; prostomium=region anterior
to such).

58 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

and slender. Neither the right, nor the left antenna is permanently
responsible for the furnishing of the opercular stopper, for out of
92 specimens examined, in 50 cases the right antenna—ve. that one
belonging to the right branchial fan—performed the opercular duty,
having the stalk elongated and the extremity swollen into the usual
opercular plug. In the remainder, viz. in 42, the left antenna was
become the functional operculum.

) This fact that in practically equal number of cases, the operculum
is devoloped indifferently from either the right or the left antenna,
is obviously of extreme importance in any attempt to trace the story
of its origin and subsequent history. Before making this attempt,
we will proceed to notice the more important of the aberrant forms of
antenna and contrast them with the normal form, and with its
homologue, the functional operculum.

The Operculum :—The normal form is doubly infundibuliform,
fairly well figured by Johnston (1) for his Serpula reversa, which
I am convinced is the same species as the present.* The upper cup
is beset with 12 to 17 bipinnate spinous processes, while the lower
has a multiserrulate margin, the serrations being continued as grooves
for some distance downwards on the inside as well as on the outside
(Pl. v, Fig. 11). i

The form is subject to not inconsiderable variation within certain
limits. Thus the larger specimens count more pinnate process than
the smaller, and the relative proportions of the two cups are
inconstant.

One case was however very remarkable, for the lower cup was
absent, and represented solely by a large elongated swelling as shown
in Fig. 14, while the processes which represented the pinnate spines
of the normal upper cup, were merely rather deep crenulations with
smooth margins. Fig. 12 and 13 show intermediate stages in this
variation, showing in Fig. 12 a great swelling of the lower cup and
a decrease in size in the pinnate processes above, while in Fig. 13,
these spines are still further reduced and all trace of the crenulated
margin of the lower cup lost. In this case also, the part representing
the lower cup is much swollen. Figs. 12, 18, and 14 are therefore
perfect gradational steps in the retrogression in shape of a normal
operculum (Fig. 11).

The Antenna :—The normal form is + to } the length of the _
operculum. The average length of those of adult specimens of

* The only differences I can trace are that S. reversa is solitary and has more
branchie and more lateral teeth on the spinous processes of the opercular cup;
S. pectinata occurring in colonies and being on the average smaller than S. reversa.
But I have traced all intermediate grades, so that the differences are not great

enough to constitute more than a variety. Fig. 15 shows typical form of operculum
of S. reversa.

CONTRIBUTIONS TO THE STUDY OF VARIATION. 59

15mm. long is ‘75mm. The apex is swollen into a somewhat conical

bulbous form, and beneath this is a narrow constriction, followed by

another slight swelling, which passes gently into a short cylindrical

stalk (Fig. 1).

Of abnormal antennze, there was a perfect series grading from
the normal form as described, to one that could scarcely be distin-
guished either in size or shape from that of a perfectly formed
normal operculum. ‘These gradations are outlined in Figs. 2 to 10.
Fig. 2 represents a form common to several specimens. In it the
equator of the terminal swelling is scored by shallow vertical grooves.
The next stage (Fig. 3) is where the equator besides being grooved,
is slightly raised into a serrulate and grooved rim. In Fig. 4, is a
form where this is accentuated, while the constriction beneath the
terminal swelling is much more emphatic. Another specimen had
the antenna (Fig. 5) one-third the length of the operculum, the
terminal knob being modified into a miniature of a true opercular
upper cup, and hiding entirely—for the first time in the series—
the conical apex of the organ.

In all these instances, the lower swelling was nearly normal.

Following on Fig. 5, we have a form such as Fig. 6, where, with
as well developed an upper cup as in the preceding, the lower has also
started to develop, taking the form of an obscurely serrated collar
at the base of the upper cup. 3

Finally in Figs. 7, 8, 9 and 10 we have a number of cases where
‘both cups are well developed, and closely approach the form of the
normal operculum. Keeping pace with this series of gradations in
development, was the growth in-length of the stalk of the pseudo-
operculum. That shown in Fig. 2 was rather stouter, but not
much longer, than the normal form of antenna, 4 was rather longer,
5 was one-third the length of the operculum, while the remainder
varied from one-half to all but equal length with the same organ.

The forms shown in Figs. 2, 7, 8, 9 and 10—those at the begin-
ning and the end of the series—were the most common.

Summing up the foregoing facts we find that :—

a. The operculum is developed on either the right or the left
antenna inconstantly.

b. The non-opercular antenna is normally cirrus-like with two slight
swellings towards the further end.

c. The same organ in 257/ of instances is abnormal, showing all
manner of degree of approximation to the form and size of
the functional operculum.

Before considering further the meaning attaching to the varia-
tions as above set forth, let me enumerate the principal points

60 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

already known concerning the homologies of the branchie and the
operculum in Serpulids and their near neighbours, the Sabellids.

A. Firstly, from an examination of the nerve supply to these
organs, Quatrefages (2) found “that in the Sabelline as in the
Serpuline, the branchial nerves arise directly from the cerebral
ganglia as antennary nerves” (7.¢. in the position which such nerves
have in such forms as Nerews) “and among the Serpulids a slender
branch springs, on each side, from the principal trunk and leads to
the base of the two opercula, as well to the rudimentary one, as to the
one completely developed. The branchiz and the opercula therefore
correspond to antenne..” Pruvot (8) further shows that the antennee
modified into gills in Serpula, are the second pair, those large
organs that in Nereis, Polynoé, &c., are known as palpi.

B. Embryology shows that very early there appear (Sabella)
two ciliated wing-like processes on the dorsal aspect, which shortly
after divide each into two slender lobes which constitute the first
four branchial rays, their number augmenting rapidly by budding
on the ventral side (4).

C. Next examining the near relatives of Serpula, we find in
Sabella no opercula, but in place, there are two slender, simple dorsal
processes occupying the same relative position and having the same
innervation or nerve-supply as the opercula of Serpulids—whence we
may justly infer that they had similar origin.

In some Sabellids (Othonia) these simple antenne are wanting,
as is the case too with a number of the Serpulids. Thus Apomatus
and Filigrana possess only branchiz and to make amends for want
of a true operculum as in the more typical species, in these the
summit of one or more of branchiz—which are of the usual bipmnate
style—is enlarged in a bulbous manner into a pseud-operculum.

D. Finally Fritz Miiller (5) has described a Serpulid which
when first observed had but three pairs of pinnate gill-filaments, but
which in a few days time, he found had developed a clavate oper-
culum at the extremity of one of the filaments. In the course of
three days more a new pair of branchial filaments had sprouted forth
and the opercular peduncle had lost its lateral filaments.

So much for collateral evidence. Now let us see if we can
gather the threads together, and make a web of fairly good strength.

From the frequent assumption of opercular shape by the or-
dinarily non-functioning and simple antenna in Serpula, and from
its inconstancy to one particular side, we may justly infer that this
variation is atavistic, and therefore that at one time, Serpula pos-
sessed two functional opercula. Then, from the corresponding
relative position of the organs, we have already inferred that the

CONTRIBUTIONS TO THE STUDY OF VARIATION. 61

opercular processes of Serpula are identical with the simple antenne

of Sabella.

Now in the latter-animal, we have evidence (B, ut sup.) that in
the course of development, the branchial filaments are at first simple
and antenna-like, so as we know by--A that the branchie and the
antenne are in reality homologous—having the same innervation—
we may conclude that the antennw in Sabella are the unaltered
jirst dorsal parr of organs that result from the splitting of the
wing-like processes of the very young larva, while the other two
lobes of this winged organ and the others that arise by budding on
the ventral side, become bipinnate and function as gills.

Now in Serpula, I believe the course of evolution was probably
as follows :—First came a Sabella-like stage with simple antenne,
but probably these were larger proportionately than those now seen
in thisanimal. Next the ends of the antenne became swollen to act as
stoppers and to close the tube against intruders. Finally one aborted,
and being useless, was reduced to an insignificant filament, which
occasionally reverts to its former well developed condition. By this
explanation I avoid Fritz Miiller’s supposition of a Fuligrana and
Protula ancestry, and this seems to me advisable, as there appears
no record, save Miiller’s own very incomplete and vague observation,
of the opercular filament ever being pinnate, either in variation. or in
larval development.

I incline to the belief that Filigrana, Protula, &e., had inde-
pendent evolution to Serpula; probably by the development of all
the processes of larval “wings” into pinnate gills, and the subsequent.
formation of false opercula on the summit of one or more of these.

REFERENCES :—
1. Johnston, Geo. —Cat. of Worms in Br. Mus., 1865,
p. 270, Pl. xx, Fig. 6—7.

2. Quatrefages, A. de.—Hist. Nat. des Annelés, 1865, Vol. ii,
p. 401, also Pl. iu.

3. Pruyot. —Archiv. de Zool. Hxpérim. et Gen., 2nd
Series, t. 11, 1885.
. Claus, C. —Traité de Zoologie, 1884, p. 601.
5. Muller, Fritz. —Facts for Darwin, 1869, p. 113.

EXPLANATION OF Pu. V, Fics. 1—15.
Serpula pectinata.

Fig. 1.—Normal antenna; Figs. 2—10.—Abnormal forms of the
antenna,

62 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

Fig. 11.—Normal form of Operculum; Figs. 12—14,—Abnormal
forms of same.

Fig. 15.—Operculum of S. reversa. Note:—All the figures are
drawn to the same scale.

III. ABNORMALITIES IN THE MUSCULAR BANDS OF SALPA.

Of over 200 specimens of larval Salpa mucronata-democratica
(solitary form) that I recently examined one by one, only some three
shown any marked sign of abnormality. Of these, two are figured
Pl. v, Figs. A, B,and C. The first two figures, A and B, represent the
two lateral views of the same animal; C, the dorsal view of another.

In every respect saving in that of muscle arrangement these
individuals were quite normal, but C showed a blending of bands iii
and iv for a short distance, as shown, and this case is of comparatively
little importance. The other example, figured in C and D, is a
much more curious instance, and is of high value to the student of
variation. Therein all the muscle bands save the Ist and the 7th,
branch and anastomose in an extremely complicated manner—ren-
dered clear however, by reference to the drawings.

Without entangling ourselves in the rival theories as to the
primitive character or otherwise of the pelagic Tunicates, the
variation I now record can be used as one link in the chain of true
evidence that will some day be forged explanatory of Ascidian
descent. Probably the variation is atavistic, and if so, points directly
to a state when the musculature was not a nearly regular arrange-
ment of more or less encircling bands, but was continuously, or at
least irregularly, disposed over the whole body, perhaps much in
the manner now to be seen in the muscle arrangement of Ascidia
mentula. .

Gegenbauer (Comp. Anatomy, 1878, p. 395) from reasoning
based on other foundations, arrived at the same result, stating that
in the Thaliacea, “the hoop-like formation arises from the differen-
tiation of a primitively continuous muscular layer. Gaps arising in
this, became gradually larger until the breaking up of the layer into
separate hoops is brought about ” ;—a statement that receives very
important direct confirmation from the instances of irregular banding

that I have figured.

I may add that the abnormal specimens, described in the
above note, as well as in the preceding one dealing with the Serpulid
operculum, are carefully preserved in the permanent collection of the
Jersey Marine Zoological Station.

Journ. of Mar. Zool. and Microscopy. Vol. I. Pl. V.

oN Mf
NRA

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Gh)
Nl ON

WuneyA lal
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Faces ww

Jas. Hornell del ad Nat.
JERSEY BIOL. STN.

ABNORMALITIES IN SERPULA AND IN SALPA.

MICROSCOPICAL STUDIES IN MARINE ZOOLOGY.

BY JAMES HORNELL.

Stupy VII. THe METAMORPHOSES OF THE MANTIS SHRIMPS
OR SQUILLIDA.

Asi Squinna Mantis.

The Mantis Shrimps, the Squillide, are among the least known
of the larger crustaceans found on our shores. Essentially a southern
type, the two species of this family that occur in British waters, have
been met with on the southern coast only, and if we were to judge
from the few captures reported, we should account them extremely
rare. In reality, one of the two—Squilla desmarestui—is not
uncommon along the shallower shores of Jersey, but as it takes up
habitation in deep burrows among the roots of the sea-grass (Zostera)
in a zone never uncovered by the tide, one can understand how rare
in appearance it may be—how abundant in fact in some favourite
localities. On several occasions, immense numbers have been cast up
on the Jersey coast after great storms. Their homes in the Zostera

64 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

beds of the Laminarian zone had been devastated by heavy surf due
to the bursting of storms coincident with the furthest receding tides
of the year, and the Squillids forced or frightened from their burrows,
and helpless to withstand or get clear of the dashing breakers, had
been buffetted to and fro, to be finally thrown in multitudes upon
the beach.

The Squillide, the sole members of the order Stomatopoda, are
distinguished from the other order of large Crustaceans—the Deca-
poda (Lobsters, Crabs, &c.)—by a different arrangement for breathing
and by a different function to which certain of the anterior limbs
are put.

For the purpose of comparison, let us take the Lobster as type of
the Decapoda. In it, the three divisions of the body of an ideal higher
crustacean—head, thorax and abdomen—are reduced to two, by the
fusion of head and thorax to form the cephalothorax. This, pro-
tected by a great shield, the carapace, is furnished with 14 pairs of
appendages. Taking these in order from before backwards, we have
one pair of stalked and moveable compound eyes; two pairs of
sensory organs, the antennz; one pair of stout jaws or mandibles ;
two pairs of weaker jaw organs, maxille ; followed by three pairs of
appendages which in structure are midway between that of the
walking limbs and that of the maxille, and as they share in the work
of preparing food and closely surround the mouth, they have received
the name of foot-jaws, or maxillipeds. Next come five pairs of large
walking or ambulatory limbs, pereiopods. Of these, the anterior pair
are enormously enlarged and form the chele, or pincers, powerful
organs for seizing and tearing prey. The second and third pairs have

also small pincer terminations, but the third and fourth end in
simple claws.

The abdomen consists of five well-marked rings or somites,
bearing each a pair of two branched (biramous) swimming feet or
swimmerets, followed by another somite bearing much enlarged
flattened swimming feet. A large, strong plate, telson, forms the
hinder extremity of the body and with the plate-like limbs of the
preceding somite, constitutes a powerful flapping tail—the so-called
caudal fin. In all probability, the telson represents a true somite
once provided with swimmerets, for the anus opens on the under side
of it, and further, minute moveable points, esteemed to be vestiges of
swimmerets, have been observed upon the telson of the common
prawn, Paleemon serratus.* If this be so, the abdomen consists of
seven somites ; and as each pair of limbs attached to the cephalothorax
is believed to indicate an original somite, we arrive at 14 as the

* Bell, History of Br. Stalk-eyed Crustacea, p. xx., London, 1853.

MICROSCOPICAL STUDIES. 65

number of somites composing this part of the body. But several
weighty reasons point to the eyes as not representing a somite, and
this reducing the number to 18, we find the entire body to consist of
20 somites. And this number not only characterises the Decapods, to
which the Lobster belongs, but equally the whole of the higher
crustacea. In some species, indeed, the thorax is distinctly jointed
after the fashion of the abdomen, emphasizing clearly the primitive
segmentation of the former region.

In the Lobster as in all Decapods, the breathing organs consist
of lancet shaped gills composed of innumerable closely packed plates
or lamelle, connected with the ambulatory limbs and some of the
maxillipeds, and lodged in a special champer on either side, formed
by the down-turned edges of the carapace.

If we now turn to Squilla, we have to note the following radical
differences from the Decapod type. Most are apparent in the accom-
panying drawing of Squilla mantis, the larger of the two British
species.

This animal is much more active and lithe than the Lobster, by
reason of the fusion of the head and thorax being less complete.
The carapace leaves uncovered the last three somites of the thorax,
and the shortened ones bearing the hinder maxillipeds are also not
fused with this shield. Apparently then, Squilla shows a more
primitive form of structure than does the Lobster—for undoubtedly
the architypal crustacean had a body composed of a number of
somites of which none were fused together—all being separate and
independent. As to the appendages, the eyes are extremely curious
in shape, expanding at the summit in a broad bilobed fashion that
arrests the attention at once. Then follow two pairs of antenne, the
outer bearing a broad oval scale or squame; next a pair of strong
mandibles and two pairs of maxille, just as in the Lobster. But
here the similitude ends, for instead of three pairs of foot-jaws, there
are five pairs,—the first weak, the second formed into strong and
greatly developed prehensile claws—with toothed terminal joint
capable of folding down into a groove on the inner side of the
joint preceding, while the succeeding three are weakly organs,
with rounded penultimate joint, bearing a tiny spine-like claw.
Next, imstead of the five pairs of walking limbs characteristic
of Decapods, there are in Squilla but three pairs, and in struc-
ture they differ also, beng weak and styliform and bearing a
delicate outer branch (exopodite), which disappears entirely in the
Decapods—one of several reasons stamping the latter group as more
modified, more distant, from the primitive co-parent, than the
Mantis Shrimps. As to the abdomen however, the form of the
appendages remains essentially the same, saving that in Sqwilla the

66 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

first five bear gills—beautifully tufted or feathered, and kept con-
stantly in movement by the incessant paddling of the limbs where-
from they spring. No gills belong to the anterior part of the body ;
hence the carapace is small as it does not require to bend down
laterally to form gill chambers as in the Lobster. ©

Good as the drawing given above, in life Squilla would scarcely
be recognised by it. No great seizing claws are visible, indeed none
of the maxillipeds are in evidence. I remember how, when I found
my first specimen, my heart sank very low—my capture was but a
sorry one—the great claws were gone! And then as I little by little
examined more carefully, my spirits rose again—for there, snugly
folded up beneath the shelter of the projecting margins of the
carapace, were the two lost limbs, and equally safe were the other
foot jaws hidden closely away between the bases of the great claws.
A moment’s thought wil! show how necessary it is for animals living
in a narrow burrow to have means of packing away, in small compass,
great limbs that are of no service except in procuring food, and which
otherwise would be getting m the way continually. In leisurely
swimming, the abdominal limbs—the swimmerets—are used as
paddles—but they by no means do all the work for the large oval
squame of each of the second antenne paddles assiduously and must
be of great assistance.

The development is singularly interesting. Unlike the Deca-
pods, the Mantis Shrimps do not carry their spawn about till hatched,
attached to the swimmerets, but deposit it in their burrows in the
Zostera meadows—a great difficulty in the way of the study of the
embryology of this animal.

Upon emerging from the egg, the larva is very simple in struc-
ture, soon assuming the form shown in Pl. vi, Fig. 3. A great shield
covers nearly the whole of the body. In front, this carapace is drawn
out into a long spine or rostrum ; behind, into two other but smaller
spines, with a third tiny one midway between these two last. The
eyes are very large and show no trace of any stalked condition.
Indeed this sessile form characterises the early larval stage of all the
higher crustaceans when normal, and clearly points to an ancestry
with unstalked eyes. Two pairs of tiny antenne, two mandibles and
two pairs of maxillee are present, together with five powerful biramous
maxillipeds, co-equal in size—saving the second pair, which in their
slightly stouter form, forshadow the great clawed prehensile second
maxillipeds of the adult.

The three succeeding somites of the thorax are clearly seen from
the first, but without sign of any appendages. In the very early
stage a large spinous-edged telson articulates with the hindmost of

Journ. of Mar. Zool. and Microscopy. Vol. I. Pl. VI.

Jas Hornell, del ad Nat.
JERSEY BIOL STN.

METAMORPHOSES OF CRUSTACEA.

Journ. of Mar. Zool. and Microscopy Vol, I., Pl. VII.

Led ee SO

Jas. Hornell, del ad Nat.
JERSEY BIOL. STN.

STRUCTURE OF ANEMONES.

MICROSCOPICAL STUDIES. 67

these limbless thoracic somites, and as time goes on, the true
abdominal somites appear at this point of junction and simul-
taneously tiny limbs sprout out from these newly formed parts. In
Fig. 3 two pairs are shown in an early sprouting stage. This, the
Erichthus or Glass Shrimp stage, was long mistaken as representing
a separate animal, and before going further, let me point out why it
does not receive the name of Zoéa, as the young larve of the
Decapods are so well known by.

If the newly hatched young of the Common Shore Crab
(Carcinus) be examined they will be seen to possess apparently
the same body parts as the Squilla Hrichthus. A large carapace
covers the fore part of the body, and a tail unprovided with limbs
follows, ending too in a broad telson. Yes, but here most curiously,
the hinder part of the thorax is not yet in any way recognizable, and
the tail portion is true abdomen and not thorax as in Squilla; seven
pairs of appendages are present; the two pairs of antenne, the
mandibles, two pairs maxille and two pairs of maxillipeds. The
third pair of the last named organs and the whole of the am-
bulatory limbs are absent and when they do appear, they sprout
out from the point just anterior to the
junction of thorax with abdomen. The
swimmerets appear about the same time
as paired buds from the segments of the
tail-like abdomen. Thus there is a wide
divergence between the Zoéa and the
Erichthus. In the one, the abdomen is
present from the —_==~ first,whilethe hinder
part of the thorax = is absent—in the
other, the cepalo- ApvANcED Zoiia or A Cras. thorax is present in
full segmental number from the beginning, but the abdomen is
wanting, saving for the telson.

After several moults the Hrichthus loses entirely the three
hinder maxillipeds, while synchronously the tiny abdominal somites
that have just appeared, develop their bud-like limbs into large
biramous swimmerets or pleopods, while each of the second maxil-
lipeds increases in size quite disproportionately to its neighbours
and becomes a huge somewhat chela-lke limb—differmg however
from the true chela or pincer form (seen so well in the Lobster)
in that the terminal joint is not opposable to an outgrown, huge
finger-like spine of the second, but instead folds down wpon the
second, fitting when at rest, into a deep groove running along the
inner margin of this penultimate joint. In the adult the edges of
this groove are beautifully sculptured with most delicate serrations,
and in the larvee show also, but in a coarser form (PI. vi, Fig. 4).

68 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

The larvee have now passed into what is known as the Alima
stage. The paired compound eyes now become stalked, and the
unpaired simple eye more easily distinguishable as a tiny X shaped
black speck, set at the base of the rostrum and between the bases of
the stalked eyes. As a point of interest, it may be noted that a
connection has been suggested between it and the pineal eye of
vertebrates.

In PI. vi, Fig. 5, a later alima stage is figured—just prior indeed
to the assumption of adult form. Here the three suppressed maxil-
lipeds are reappearing, but extremely short (Fig. 50). In it also, the
three biramous walking limbs of the adult are beginning growth—
tiny buds on the underside of the three hinder thoracic segments
(Fig. 5c), which until the present have from the time of hatching
been free from any sign or trace of appendage.

During all these larval stages, the tiny animal leads a pelagic
free-swimming life, and is occasionally taken in the tow-net in the
sunny waters of the Channel Isles. Like other pelagic animals it is
glassy and colourless and a powerful swimmer. |

EXPLANATION OF Fics. 3—5, Pate VI.
Metamorphoses of Squilla.

Fig. 3. The recently hatched animal in the Hrichthus or Glass-
shrimp stage ; actual size 4 mm. (inclusive of rostrum).

Fig. 4. Early Alima stage of another species, ventral view ; actual
size 44 mm.

Fig. 5. Advanced Alima stage, dorsal view; actual size 11 mm.
(In this figure, the rudimentary three hinder pairs of
maxillipeds—5b ; the bud-like ambulatory limbs—5c ;
and the well-developed ambulatory limbs—5d, are not
figured for clearness sake).

5a,a mandible; 5b, one of the three hinder and rudimentary

maxillipeds, X 55; 5c, Section through the hinder part

of the thorax, showing the first appearance of the am-
bulatory limbs as buds, X 18; 5d, a swimmeret, X 18.

Lettering the same in all figures, viz:—I. anterior antenne ;

II. posterior antenne ; III. mandibles; IV & V. 1st and 2nd maxille ;

VI, VII, VIII, IX & X. maxillipeds; XIV—XVIII. swimmerets ;

e. paired compound eyes; e. unpaired simple eye; lab. labium ;

bl. branchial plate of maxilliped; cp. carapace; 7. rostrum; al. ali-

mentary canal; a. anus.
Norrt.—Probably the two Alima forms figured, belong to the
same species of Squilla, viz., S. desmarestit.

MICROSCOPICAL STUDIES. 69

VIII.— Tur PHYLLOSOMA oR GLASS CRAB LARVA OF SCYLLARUS.

Pelagic animals are, without exception, of the highest beauty,
but, saving for the wondrous loveliness of the pelagic Coelenterates—
the elfin-locked Medusids, the glassy Cydippe, and the phosphorescent
and elaborate Siphonophores,—what can compare with the quaint
“ Glass Crabs ” of the older writers. These, long known by the name
of Phyllosoma, were considered a separate group of animals, till
Couch in 1857 hinted vaguely to the British Association that they
were in reality the larval forms of certain Decapod Crustaceans,
notably of Palinurus vulgaris, the Common Crawfish. Couch had
been studying for some years the development of the larger Crus-
taceans, and the pity is, that through imadequate training he was
unable to utilize to full, or even moderate advantage, the oppor-
tunities that the practically unexploited field of this study then
afforded.

Couch’s figures were anything but accurate, and his work did
little but point the way. Indeed not till so long after as 1870, was
the full value of the relationship definitely traced and worked out,
and the achievement is one of the many that Biology owes to the
indefatigable perseverance of that prince among naturalists—the
veteran Dr. Dohrn.

In that year Dr. Dohrn detailed the development of a very
near relative of Palinurus, viz. of Scyllarus arctus, while in the egg,
and also during a short period in its free swimming life, showing
that there is absolute identity between the hatched larva and a
certain form of Phyllosome.

Other naturalists have extended these observations, and to-day
the only points requiring much elucidation, are the final metamor-
phoses just prior to the period when the Phyllosome larva changes to
the adult. A limit seems to be set to the age to which the larve
can be reared in confinement. For a while all goes well, then the
captives begin to find some necessary condition of life to be wanting,
and rapidly decrease in numbers, till not one survives.

But before describing the larval form, let us glance at the chief
points in the anatomy of the adult. Scyllarus arctus is one of the
rarest of the large Crustaceans living in British waters, and like the
Squillidz, found only in the English Channel; just on the northern
boundary of the great Mediterranean zone—just where this zone
grades into that of the northern regions. Its captures on the
English coast can be traced in paragraphs in scientific journals, and
only in the Channel Islands is it frequently enough met with to
receive a vernacular cognomen. In these islands the fishermen speak
of it indifferently as the Bastard Crawfish and the Square-nosed

70 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

Lobster; sufficiently graphic epithets—strong in the descriptive
name-power that lurks so often in the rough harvesters of the sea.

Scyllarus is a strange mingling of the uncouth and the beau-
tiful. His form is clumsy; short squat body with weak legs and
with disproportionate development of the second antenne. ‘These,
which in the Lobster and the Crawfish (Palinurus) are elegant,
long, gently tapering rods equal and exceeding in length that of the
body—dwindle in Scyllarus into short broad plates very evident in
the aoe drawn beneath.—But the coloring! That is superb: In

PO general tint a rather light chestnut brown,
the depressions and deep lines of the closely
covering fine sculpturig are of deeper tone,
almost black; in striking contrast to this the
anterior portion of each of the abdominal
rings is of a brilliant scarlet. The short eye-
stalks are also scarlet, giving these organs,
with the black pigment disc showing distinct
through the transparent cornea and retina,
a striking resemblance to those little scarlet
and black beans (Abrus), which bottled up,
form such familiar objects on the mantel-
shelves of our seafarmg men’s homes. Un-
doubtedly Scyllarus is the most beautifully
coloured of our large Crustaceans.

The number and arrangement of the limbs are the same as
in the Lobster, but unlike the latter animal, all the five pairs of
ambulatory limbs are formed on the same pattern—each terminating
in a short sharp claw—none pincer-like as in the Lobster.

A very different creature issues from the egg. Instead of a
short legged, stout body, an elegant glassy-transparent and colour-
less, leaf-like organism appears, delicate, fragile, with four enormously
long, six-jointed limbs, freely armed with spines. And two of these
spider-like limbs give off branches ending in delicately plumose hairs.

Further and minute examination shows the body to consist of
three distinct divisions—a broadly oval flattened head, larger in size
than the remainder of the body; a thorax, rounded and likewise
flattened leaf-like, and of about half the size only of the head ; lastly
the abdomen, least developed of the three parts, narrow, elongated,
and without appendages.

HEAD: From the anterior margin of the head spring two pairs
of simple antenne, the posterior extremely small, only some fifth the
length of the anterior ones. Between these lie two great facetted
eyes, borne on long stout peduncles; while in the median line just
between the bases of the eyestalks, is a tiny X shaped mass of dark

ScyLLARuS ARCTUS.

MICROSCOPICAL STUDIES. (fa

pigment representing the unpaired simple eye, of the same structure
as that of the Squilla larve.

The mouth is situated on the under side of the head, midway
between the front and hinder edges, and is surrounded by an upper
lip or labium (PI. vi, Fig. 2), two stout mandibles, and two pairs of
maxille, the first large, with two appendages—and working inwards
in the same plane as the mandibles; the second pair, on the contrary,
are small and rudimentary and appear not to function.

Of the maxillipeds—the first pair is non-existent, showing not
the slighest trace : a very peculiar fact and characteristic of Scyllarus,
distinguishing from the youngest Phyllosome of Palinwrus where this
appendage is just visible as a tiny cylindrical process.* The second
however, though slender, can be easily resolved into six joints, while
the third is more than thrice this length and proportionately stouter.
Behind this are thrée enormously elongated spider-like limbs, the
true ambulatory legs or pereiopods; each is six jointed—the terminal
one claw-shaped and reminding one sharply of the similar appearance
of this joint in the adult. The first and second ambulatory limbs are
biramous, for there springs from the further end of the second joint
in each, a paddle-functioning jointed and plumose appendage which
represents the exopodite. The third is unbranched, but a knobbed
projection on the second joint indicates where the exopodite is about
to sprout forth. In older larve the third maxilliped also develops a
plumose branch. Four pairs of limbs,—the third maxillipeds, and the
six pereiopods are the only appendages of the thorax at this stage,
but as age advances and repeated moults take place other pereiopods
appear at the point between the base of the abdomen and the third
perelopod; these in turn assuming the biramous character of the
first formed.

* In this statement I give the accepted view (Dohrn, Zeitschr. fiir wiss. Zool.
1870). My own examination of the young larve, points rather to the missing
appendage being the second maxilla and not the first maxilliped. Undoubtedly
one or other is missing, for between the first maxilla and the second maxilliped,
there is but one organ, and the reason why I think this to be the first maxilliped is
that the somite it belongs to, is clearly defined and shows no trace of having another
somite between it and the equally well defined somite bearing the second maxilliped
(see Fig. 2). On the other hand, the region in front of the somite bearing this
uncertain appendage, and between the latter and the first maxilla, is extensive, and
bears no appendage. The shape too, of the uncertain limb, is in favour of my view ;
it consists of a stout, rather fusiform basal joint, bearing a tiny terminal joint from
which spring four long and highly plumose hairs. Now in the Phyllosome of
Palinurus which possesses both second maxille and first maxillipeds, Cunningham
(Journ. Mar. Biol. Assn., New Ser., Vol. II, No. 2, p. 147) describes the former as
rather large and foliaceous and gives the figure of a distinctly biramous limb; while
the latter he speaks of as being each a simple, small but distinct conical stump,
a description much more fitting the organ in the Scyllarus larva, than that of
the second maxilla, for it is in nowise foliaceous, nor yet biramous. Not having
examined the embryo nor yet any advanced Phyllosomes of Scyllarus, I cannot
however give my view as more than an opinion.

72 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

The third part of the body, the abdomen, is trivial and shows no
signs of the importance it will attain to in the adult condition. No
limbs are present, not even a caudal fin—the intestine can however
be traced, traversing the entire length, and opening by the anus at
the extreme end. A few very faint transverse markings can be made
out, indicating the limits of future somites.

Now what is the significance of this most peculiar larval form ?—

Only Scyllarus and Palinwrus among the Decapods possess it.
Of the others, the vast majority, especially the solid phalanx of the
Crabs, leave the egg in a totally different condition, viz.,in the Zoéa
form, 7.¢€., with head and abdomen well developed but without thorax
and abdominal limbs. On the other hand the larvee of the Lobster are
never so primitive. Thorax and thoracic limbs are present from the
first though abdominal limbs are at first absent. A few others have
still further abbreviated metamorphosis, ¢.g., the Fresh-water Crayfish
is hatched practically in adult form, while conversely a few prawns
(Peneus) leave the egg in the curiously primitive Nauplius con-
dition that characterises specially the Entomostracans and Cirripedes
and pass through numerous other stages ere reaching the adult. -

To either of the last two, Phyllosoma bears no relation, and
analysing the other couple, it is at once seen that the Zoéa form is
also inadmissable. This one has no thorax developed, while in
Phyllosoma such is of great importance. We are thus left with the
Lobster larva (early stage), a form at first sight nowise resembling a
Phyllosome. But stay; both show distinct head, thorax and abdomen ;

ADVANCED LARYA OF THE LOBSTER.
in both, limbs are developed on the first two divisions, and both are
without appendages on the abdomen. All parts bear comparison in
the two forms, and the differences which, first sight, appeared so
great as to forbid thought of any probable fundamental similarity
until arrived at by analysis, are after all but comparatively trivial
differences of proportion. But if the larval forms of the Palinuride
be so closely akin in fundamental structure (homology) to those of
the Lobsters (Homarus) how did the present striking divergence in
the form of the respective regions arise? The answer must be
sought in the different habits of these animals during the larval life.
And the chief determining habit centres in the different mode of

MICROSCOPICAL STUDIES. 73

progression adopted by the two. The Lobster larva moves largely
by a jerky movement or flapping, produced by the muscular con-
traction of the powerful abdomen: the Phyllosome on the other hand
swims entirely by the paddling action of the thoracic legs. In the
one case, the animal chooses a mode of progression requiring a well
developed and muscular abdomen—in the other, Phyllosoma elects a
method that dispenses with the need for such a strong tail, hence the
non-development of that during such period when indeed it would be
an encumbrance and a danger. Then:as to the change in form of
the rest of the body—such is probably the outcome of the greater
pelagic habit of the Phyllosome. The latter has a much longer
-surface-swimming larval life (so far as my observations go) than
larval lobsters, hence the necessity for a greater or more perfect,
defensive transparency. Such, obviously, can be better attained in
a thin flattened bedy, than in a thick muscular one.

Surely this study of individual development is without superior
in fascinating interest among Zoological problems—its interest, too,
enhanced by the great light it sheds upon the past development of
the race. But while its importance in this sense is so great, let us
beware of blind acceptance of that present day biological shibboleth
“Ontogeny recapitulates Phylogeny,’ meaning that the history of
the development of the individual sums up and points out the
various stages passed through by the particular race in the course
of its evolution. Such a theory I doubt not is useful to work by,
but it must have intelligent and reasoning and ultra-careful hand-
ling, or further false pages will be added to the already too many
that have of late years been inserted in our scientific journals by
hasty and theory-ridden writers. The harm done in this way is
incalculable and unfortunately difficult to cope with or to stem.
Every such wildly reasoned generalization or inference is a false
finger post upon the scientific highway. Therefore let us beware of
setting up even one more. ees

EXPLANATION OF Fics. 1 AND 2, PLATE VI.
The Phyllosoma larva of Scyllarus.

Fig. 1. Early Phyllosome larva seen from the dorsal surface ; actual
length (tip of rostrum to end of abdomen) 15 mm. ;
e. paired compound eyes; e’. unpaired simple eye; c. head ;
th. thorax ; ab. abdomen; I. anterior antenne ; II. pos-
terior antenne; III. mandibles; IV & V. 1st and 2nd
maxille ; VII & VIII. 2nd and 8rd maxillipeds; IX, X
& XI. 1st, 2nd, and 3rd ambulatory limbs; XIII. 4th
ambulatory limb beginning to sprout; eap. exopodite ;
g. rudiment of green gland ; l. largely lobed liver.

74 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

Fig. 2. Enlarged view of mouth organs; lab. labium ; mand. man-
dibles; 1 maw. & 2 maz. Ist and 2nd rpawilles 2a, stout
limb of mandible; 2b, a Ist marily = Roth further
enlarged. 3

Stupy IX. THE STRUCTURE OF ANEMONES.

Ever since that comparatively recent period little more than a
century ago, when, for the first time, men’s eyes were opened to the
beauties of the smaller marine creatures, the sea-anemones have held
perhaps the foremost place of honour in this artistic appreciation.
‘Their very name—the implied resemblance to the gorgeous scarlet-
‘rayed, black disc’d anemones that give such wealth of colour to our
‘old-fashioned gardens—suggests this thought. And our German
‘cousins vie in doing similar honour, a higher one if possible, by
calling them after the queen of flowers, for they name them Sea-roses
(Seerosen). Even the learned and usually strictly practical framers
‘of our scientific nomenclature have experienced the same spell, for is
‘not Anthozoa—one of the terms applied to the Anemone group—
‘merely the Greek rendering of “ Flower-animals”? Few marine
-animals are nowadays better known. Everyone who has started
‘even the smallest of small aquaria—if only in the form of a big
pickle-jar or an earthenware pan—has begun by stocking with some
common species of anemone; mayhap the brownish-red Beadlet
‘(Actinia) with its necklace of lovely blue beads; or perhaps the
‘stout fleshy Tealia, with body covered with strange warts, each
holding firmly some fragment of shell or pebble; or yet again, he
may have started with the medusa-locked Anemonia sulcata
“(Anthea cereus). Their hardiness, as well as their beauty, conduces
‘to this popularity.

If we take any typical anemone, we find it to be s extremely
“primitive structure. Usually the body consists of a short, stout,
hollow cylinder (column), attached at the base to some rock or
boulder, by a sucker-like pedal. disc, often spoken of as the foot.
The opposite or free end, the peristome or mouth disc, bears the
‘mouth, slit-like in shape, and surrounded by several concentric rows
of hollow, finger-like tentacles, the older towards the centre. At the
point where the peristome merges into the column, is a distinct
ridge, the margin (PI. vii, Fig. 3, m.)

- No anus is present. The mouth, 0, leads into a short msophagus
-or stomodeum (st), not continuous with a stomach and intestine as
in the higher and more familiar animals, but ending in a free,
pendant margin, opening direct into the great body cavity, the
celenteric space. The fundamental form of this simple alimentary

MICROSCOPICAL STUDIES. 75

arrangement can be at once understood if we take a hollow india-
rubber ball, cut a small slit at one end, and then push the edges of
the slit well down into the interior of the ball; the short tube
thus formed will represent the stomodeeum.

Kach of the two angles that bound the extremities of the mouth
slit are continued downwards along the cesophagus as a deep, richly
‘ciliated groove—the siphonoglyph. Most anemones have two of
these grooves but some (Peachia, Cerianthus) have but one.

The siphonoglyphs remain open, even when the animal is
greatly contracted, and they appear to be useful in keeping up a
constant flow of water through the esophagus.

Numerous vertical partitions, ingrowths of the body wall—the
mesenteries—join the hanging cesophageal tube to the outer wall
of the body, and serve to break up the great body-cavity into a
number of radial longitudinal chambers; an arrangement clearly
shown in Fig. 1, representing a transverse section through the upper
part of an anemone. The section of the cesophagus appears as a
small inner circle, connected to the large outer circle of the body
wall by twelve radial lines, the sections of the mesenteries. But in
the lower part of the Anemone’s body-—below the level of the
cesophagus, the mesenteries form incomplete partitions, and show
as in Fig. 2, as though a cart wheel had had the hub broken out
leaving the rim with the broken spokes projecting inwards. The
free edge of each mesentery is swelled out distinctly into three
longitudinal lobes, the middle one crowded with nema wcy sts and
gland cells, the lateral ones clothed with strong cilia.

The mesenteries are arranged in pairs. Some reach across
to the csophagus—the primary; others fall a little short of it—
the secondary, and yet others may be still shorter—the tertiary.
Of these the primary are the first to appear. The secondary appear
next in succession, in pairs between every two pairs of primary. In
Fig. 2, four pairs only of secondary mesenteries (2 m) are present,
while the full complement of primary, six pairs, is obvious. Each
mesentery has a very pronounced longitudinal ridge on one face
running from peristome to base (lm), and except in two pairs, the
ridges in each pair face one another. The two exceptional pairs are
‘on opposite sides of the cesophagus. In them, the ridges, in the
members of each pair, face outwards, and the presence of these
directive mesenteries (dim) serves to divide the animal into a right
and a left half, and in certain cases, even into a dorsal and a ventral
division. When two siphonoglyphes are present, each gives attach-
ment to the inner margins of one of these two pairs of special septa.

The chamber enclosed by the members of each pair of mesen-
_teries is the intraseptal (im); that between the outer members of

76 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

adjacent pairs, the interseptal (7s). Some slight direct communi-
cation with the exterior, is usually provided for these chambers, by
a pore (tp) at the tip of each tentacle, which are simply hollow
outgrowths of the peristome. Intercommunication is also allowed by
the presence of one, sometimes of two pores piercing the mesenteric
walls just beneath the peristome (7p and op).

Examining a transverse section with the microscope, we can
resolve the wall of the body and cf the cesophagus (a mere down-
growth of the mouth disc), into three well differentiated layers. The
most obvious is the middle one—mesoglea or supporting lamina—
consisting of a thick layer of a clear, fibrillated tissue, approaching
somewhat the texture of tendon, denoted in Figs. 1 and 2 by black
bands and lines. Outer to this is the ectoderm or epidermal layer,
containing in certain regions, glands and stinging cells or nematocysts.
This is the seat of what poorly developed nerve elements there are
in these animals. ‘

On the inner side of the mesoglea, is the thin but important
layer of the endoderm, lining the entire body cavity in all its
chambers with a coating of ciliated cells, which give off strong
muscle fibres on the side in contact with the mesoglea. The
principal functions of the endoderm are those of digestion and
the provision of muscular movement.

Most anemones have great powers of contraction, being able in
many cases to reduce their bulk to less than one-seventh of that
when fully expanded. The principal muscles employed are strong
longitudinal ones running in the ridged surface of each mesentery.
The supporting lamina is much folded at this poimt, forming in
section, a beautiful arborescent pattern, and along these multiplied
faces run from base to peristome, great numbers of muscle fibres,
whose duty it is to pull down the tentacles and mouth-disc, and so
shorten and retract the animal. On the other face of the mesen-
teries the muscle fibres run transversely; so that we may describe
the disposition of the mesenteric muscles as usually longitudinal on the
intraseptal surface, and as transverse on the interseptal. The latter
towards the base of each mesentery alter their course so as to run
obliquely from the wall downwards to the base—the parieto-basilar
muscle (pbm). In the walls, the peristome, the cesophagus, and
usually also in the base, the muscular processes of the endoderm cells
are arranged in a circular direction.

No animal is more ravenous. Crabs, molluscs, and small fishes
wandering incautiously close, are entwined and pulled inwards by the
long tentacles, the while that cruel stinging cells are conveying into
the poor quivering body, a poisonous, numbing juice through innu-

merable thread-like barbs. Still struggling, the prey is passed

MICROSCOPICAL STUDIES. 77

into the cesophagus and thence downwards. At this stage, ner-
vous excitement brings about a remarkable occurrence. The free
edges of the mesenteries close together and form an improvised
stomach by the approximation of the lateral lobes. If death has not
yet occurred, the powerful stinging-cells that load the central ridge
of the mesenterial filaments complete the work, while the associated
gland cells provide digestive fluid in plenty. It is surprising how
powerful and rapid this is in action. A few hours, three to four,
secure the complete digestion of a fish or a crab nearly as large as
the anemone itself. As the prey dissolves, this nutrient fluid is
permitted to leave the improvised stomach, and flows freely into the
various septal chambers, even too, into the tentacles; the cells in
contact taking up what quantity they can. Any hard undigested
parts are ejected by the mouth.

The sexes are usually separate. Both ova and sperm arise from
similarly placed glands lying a little way from the free edges of the
mesenteries (Figs. 2 and 3, gg and ov). Many species are viviparous,
the young undergoing their early development within the septal
chambers, and only when their tentacles are just long enough and
sufficiently provided with sting cells to capture prey, are they cast
out from the mother, by way of the mouth. Often have I obtained
these baby anemones by gently squeezing the parent’s body, when,
one by one, minatures of the parent popped out through the mouth.
The Gem (Bunodes); the Beadlet (Actinia); and the Sand-
Anemone (Sagartia bellis) are examples in point.

Classification, The anemones belong to the phylum Ccelen-
terata, consequent upon having no definite tubular alimentary canal,
the mouth and cesophagus leading into a great bag-like cavity
without anal aperture. No cavities are developed within the walls of
the body; neither is a ganglionic chain present, only an irregular
loose network of ganglia and nerves.

The Coelenterata are subdivided into two classes; a simpler,
without cesophagus or mesenteries—the Hydrozoa; a more complex,
with well marked cesophagus, and numerous mesenteries—the
Anthozoa or Actinozoa, and it is to this latter division that the
animals we are now dealing with belong, and here I must remark,
that I am using the term Sea-anemone, in a wide sense, as equivalent
to the whole of the Anthozoa.

Within the bounds of this class, many very divergent forms are
found. These are ranged in two sub-classes :—

I. The Hexactinia or Zoantharia and

II. The Octactinia or Alcyonaria.
The first contains the true Anemones, most generally simple, rarely
colonial in habit, and which have their mesenteries in pairs in mul-_

78 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

tiples of six, and with usually two siphonoglyphs. The Octactinia
on the contrary, are all but entirely colonial, growing usually in
masses of many hundreds of associated individuals; the mesenteries
are some multiple of eight ; only one siphonoglyph is present, and
the longitudinal muscle ridges of all the mesenteries face towards it
(Fig. 5). For convenience, I shall call these the colonial anemones,
in contrast to the true or simple ones.

Let us now examine briefly the special points about the types
chosen in our plates to illustrate the characteristic features of these
two divisions.

Svphonactinia (Peachia) truphylla (Gosse), which we use as
type of the true anemones, is in many ways remarkable. Its body
is cylindrical, tapering to the base, which unlike that of other
anemones, is not broadened into a flat attachment disc but is nar-
rowed to a blunt point, and still more remarkable, is perforated by
a small opening. Around the mouth are set twelve stout swollen
tentacles, beautifully marked with dashes and lines of chocolate as is
too, in rather more irregular manner, the whole surface of the body,
on a ground tint of very pale pinkish brown. A stranger to the
strange convergence of outward form wrought upon animals of dif-
ferent groups by similarity in environment and in habits, would
never guess the true relationship of these animals living in the shell-
sand gravel that here and there accumulates in patches along the
shores of the Channel Islands; he would surely presume them to be
some queer coloured sea-cucumber—some Holothurian not figured

by Forbes.

In habit Siphonactinia burrows down several inches into the
sand when the tide goes down, cautiously ascending and spreading
its tentacles level with the surface as the sea returns.

Fig. 1 shows what is seen in a transverse section close under the
mouth disc. Notice the smgle siphonoglyph (sz) giving attachment
to the ventral pair of directive mesenteries. The mesoglaea forms
the central layer in all the threefold walls and mesenteries of the
body. In the section from which this is drawn, the mesoglaea has
absorbed most of the stain used and has become very conspicuous by
reason of its bright crimson and glassy appearance. Fig. 2 represents
a section below the level of the cesophagus, and shows the swollen
free edges or craspeda of the primary mesenteries, as well as a
swollen region (gg)—the ovary—some distance from the edge.

Few anemones are so useful to use for a due understanding of the
general anatomy of the class, and the pity is, that this species is becom-
‘ing extremely rare. The trouble connected with the commoner species,

MICROSCOPICAL STUDIES. 79

is that they all combine in the possession of so many and so well
developed subsidiary mesenteries that in section the apparent com-
plication becomes bewildering and confusing beyond measure to the
student to understand, to the teacher to explain.

The representative used to illustrate the second sub-class, is the
common Alcyonrwm, a colony of polyps cemented together by a
gelatinous or semi-cartilaginous matrix strengthened by calcareous
spicules. On some parts of our coasts it is plentiful, forming when
livmg and with tentacles fully expanded, an exquisite feathery mass
of life—strangely contrasting with the woeful, gruesome appearance
it takes on when dead, and battered, and cast up, a sea-waif, upon
the beach. Fishermen give it all sorts of names expressive of their
loathing, “ Deadman’s fingers,” “ Deadman’s toes,” “ Cow’s paps,” and
the like.

The colony is formed of tiny, anemone-like polyps,—each with a
row ofeight pinnate tentacles,—united together bya wonderful develop-
ment of the mesoglaea ; mdeed a distinctive name is now applied to
this tissue—coenosarc—and it adds a great defensive device against
predatory enemies, by the development within its substance of
curiously warted spicules of carbonate of lime. And these tiny flesh-
spines are not only found in the connecting matrix, but even in the
thin layer of mesoglaea of the cesophagus are some smaller ones.

Note the different number and arrangement of the mesenteries.
Instead of being in pairs, they occur in two series, a right and a left,
and the muscular swellings face downwards (towards the siphonoglyph)
in each series. Fig. 6 shows a section cut low down in the stalk of
the colony, a region equivalent to that of Sephonactinia shown in
Fig. 2; here the mesenteries are reduced to low folds or ridges.

Reproduction is rather different ; the ova and sperm masses are
not produced in special glands in the substance of the mesenteries,
but arise singly in bud-like fashion on the edge of the mesenteric
ridges (ov’ and ov). :

Besides Alcyonvwm, there are several other and diverse repre-
sentatives of this class found on our shores. There is the lovely,
light-emitting Sea-Pen (Pennatula); the equally curious if less
elegant Virgularia, and the grand Sea-Fan or rather Sea-Bush,
Gorgonia verrucosa. The organ-pipe Coral (Tubularia) and the
true red Coral (Coralliwm rubrum) are also members—their ul-
timate structure being identical with that of Aleyoniwm as described
and figured, and differing almost solely in the method of spicule
arrangement: in the one, loosely scattered; in the other, densely
packed and soldered intimately together. eo

80 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

EXPLANATION OF PLATE VIL.
Structure of Anthozoa.

Fig. 1. Trans. sec. of Siphonactinia triphylla, through region of
cesophagus, 2.¢., cut along the lme indicated by the letters
A—B in Fig. B % os.

Fig. 2. Trans. sec. of same, at a lower level, 2.¢., along line indicated
by C—D in Fig. 3. X 34.

Fig. 38. Diagram of anemone structure, shown by a vertical section
along the plane indicated by letters A—B in Fig. 1
A mesentery is cut through longitudinally on the left
side; on the other, the section passes through an inter-
septal space.

Fig. 4. S. triphylla, actual size.

Fig. 5. Surface section through a colony of Aleyoniwm digitatum,
the polyps retracted wholly. For the sake of clearness,
the tentacles which are retracted within the cesophagus,
are omitted from the section. JD, dorsal region ; V, ven-
tral region. X 9.

Fig. 6. Trans. sec. thro’ portion of stalk of a colony of A. palmatuim.

Lettering :—co, ccenosarc; cr, mesenterial filament or craspedon ;
dm, dorsal directive mesenteries ; dnv, ventral ditto; e, ectoderm of
body walls ; ¢, ectoderm of cesophagus ; en, endoderm ; gg, genital
gland; 7m, intraseptal chamber ; is, interseptal chamber; ip, inner
pore; lm, longitudinal muscle band; m, margin; 2m, secondary
mesenteries ; 0, mouth ; op, outer pore ; ov, ovary ; ov’, loose ovum ;
pb, parieto- basilar musele ; pm, primary mesenteries ; vr, peristome ;
rm, radial or transverse muscle fibres ; st, siphonoglyph ; ; sm, sphincter
muscle ; sp, spicules; st, stomodzeum or cesophagus: ¢, tentacle ;
ip, tentacle pore.

EXCHANGES WANTED.

Literature upon the Foraminifera, especially “ Challenger ”
Report, &c. Exchange or Cash. J. G. care of the Editor.

Literature upon the Hydrozoa and the Annelida; well preserved
fossils (named) ; foreign echinoderms and er ustaceans, also centipedes
and scorpions in spirit. Exchange in micro. slides, zoological
specimens, &c. Apply to the Editor.

HANDBOOK TO THE CHANNEL Is~Es. We haye pleasure in directing the at-
tention of those interested in the natural science of our islands, to the revised
edition of Ansted & Lathom’s “ Channel Islands,” 8vo., 476 pp., which has been
issued by Messrs. W. H. Allen & Co. Special Chapters are devoted to Zoology,
Botany, and Geology; 40, 16, and 48 pages respectively, and all facts have been
brought up to date. The work is profusely illustrated, and it is due to the courtesy
of the publishers that we are enabled to use their block of adult Scyllarus arctus
upon a preceding page. The published price is 7/6, and at this we will send it post
free to any part of the United Kingdom,

Che Sounal of Marine ‘Roologn
and ~ierosconp

A PLAINLY WORDED BIOLOGICAL QUARTERLY.

You. I. No. 4 SEPTEMBER, 1894.
THE LIFE-HISTORY OF THE ROCK BARNACLE,
- (BALANUS).
1B New MISTI O WE CeO OW, IMs Agisi
(PAnreh)

VERY visitor to the sea-side is familiar with the appearance, if
not with the names of the “ Barnacles” and “ Acorn-shells ”.
The spar cast up by the waves, with its forest of strange-looking
stalked shells, has often provoked the curiosity of those unacquainted
with the secrets of Natural History. Almost anywhere along our
rocky shores the countless myriads of small whitish conical shells
firmly fixed on the rocks between tide-marks, give quite a dis-
tinctive appearance to the landscape. These small creatures ap-
parently so rigid and still, have a wonderful life-history. In
medieval times it was seriously maintained that the barnacle was
only the young of the barnacle-goose. One observer desirous of
handing down his name to posterity as an original discoverer,
actually saw the young bird inside the shell of the Crustacean,
and records his observations in the following words :—“ In every
shell that I opened I found a perfect sea-fowl, the bill lke
that of a goose, the eyes marked, the head, neck, breast, wings, tail,
and feet formed, the feathers everywhere perfectly shaped and
blackish coloured, and the feet like those of other water-fowl to my
best remembrance.”—(Quoted in J. V. Thompson’s “ Zoological
Researches ”).

The young Barnacle, however, leaves its egg-shell in a much
less highly organized form than that of a young bird. It hatches
as a typical Nauplius, a larval form characteristic of the Ento-
mostraca or lower Crustacea. The Nauplius of the ordinary rock
Barnacle (Balanus) after throwing off its first cuticle is shown in
Pl. vii, Figs. 1 and 12. It has a shield-shaped carapace, and is so
transparent when living that most of the internal organs can be
easily made out. The anterior angles of the shield are prolonged,
as in nearly all Cirripede Nauplii, into a pair of horns, which are

82 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

tubular and emit a secretion formed by two unicellular glands
(fronto-lateral glands, Fig. 6; cf. also Fig. 16) on each side. Arti-
culating with the hinder end of the carapace is a caudal spine (¢. s.),
which is moved by means of a muscle (¢. fm.) in a vertical plane
together with the tail or rudiment of the thorax and abdomen, and
helps to steer the larva. On the lower side is seen another charac-
teristic organ of the Nauplius—the huge labrum or upper lip (lbr.)
This projects below the mouth (Fig. 9), and is furnished at the apex
with four unicellular glands (Fig. 5) which emit minute secreted
spherules. In front of the labrum is seen the black Nauplius-eye,
another characteristic Entomostracan feature, rarely seen in the higher
Crustacea or Malacostraca. At the sides of the Nauplius-eye are
seen a pair of delicate frontal or olfactory filaments, also found in
forms belonging to other groups of Crustacea. Behind and hidden
by the labrum is the small mouth (Fig. 9).

The posterior end of the larva is formed by a broad-based forked
spinous process (¢.), representing the thorax and abdomen of the later
stages. The large size of this region is a feature characteristic of the
Nauplii of Cirripedes. The appendages (Figs. 2, 3 and 4) as in
Nauplii generally, are three im number; the antennules (Fig. 2)
are simple, and the antenne (Fig. 3) and mandibles (Fig. 4)
biramous, as usual in Naupliu. The figures show sufficiently the
characters of these appendages. There is in every Nauplius a per-
fectly definite arrangement of the various hairs, spines and other
processes. :

The alimentary canal shows three distinct regions :—a bent
cesophagus (@.), a rounded stomach (s.), and a straight intestine (7.)
leading to the anus, which is situated, as in Entomostraca generally,
on the dorsal side of the tail; in the Cirripede Nauplius it lies just
beneath the caudal spine (Fig. 9).

The brain (Fig. 8) consists of a supra-cesophageal ganglion, on
which the eye rests, and from which the olfactory filaments are
directly given off ; behind, the brain gives off two circum-cesophageal
nerve cords, which unite below to form a sub-cesophageal ganglion.

The Nauplius swims about actively and feeds and grows rapidly,
a definite series of moults taking place.

A curious fact often misunderstood by naturalists is the way in
which, just after moulting, the various spines and hairs are at first
telescoped. This is a direct consequence of the mode of formation
of a larger organ within a smaller; thus for the long tail to arise
within the cuticle of the newly hatched Nauplius, it is necessary
that it should become folded and telescoped within the corresponding

part of the younger larva: after the moult it gradually becomes
everted (Fig. 10).

LIFE-HISTORY OF THE ROCK BARNACLE. 83

In Balanus there are altogether exactly six stages, and the
most ready way to distinguish these is by measurement. Figs. 11—
16 show the form of the carapace at each stage, and at the same
time the relative size, and certain other characters. We see, then,
that the last Nauplius stage is between three and four times the
length of the first, and whercas the newly hatched Nauplius is only
just visible to the naked eye, the oldest are easily recognisable.
During this growth highly important changes take place in both
internal and external organization. These lead up to the last larval
condition known as the Pupa or Cypris-stage. The Nauplii of
the sixth stage (Fig. 22) are beautiful and instructive creatures.
One can see already the compound eye of the Cypris-stage, at first
red and showing the retinule (Fig. 28), later black; the six pairs of
thoracic legs are visible but still lie within the cuticle, and can be
seen to take their origin in a series of paired spines on the ventral
side of the larva.

An exceedingly interesting feature about the Nauplii of some
Cirripedes is the effect of light on the direction of their movements.
At some times the Nauplii move towards the light, and at others
away from it. In one species (Balanus perforatus) wpon which the
author, in conjuction with Dr. Loeb has experimented, the Naupliit
performed daily migrations in the vessels ; in the early morning they
commonly sought the light, while a little later on and during the
greater part of the day they avoided it. Beautiful experiments can
be made on these little creatures, they can, for instance, be made to
follow a candle all round a glass vessel. There can be little doubt
that we have here a partial explanation of the daily oscillations
performed by a great number of the animals living at the surface of
the sea. When they have been sufficiently long exposed to the
light, they retire to the depths. Whether this is done for the
purpose of concealment or for some other object, it is difficult to say.

The Cypris-stage or last larval condition, is another exceedingly
interesting form. ‘The larva attains this stage, so utterly different in
appearance from the Nauplius, in a smgle moult. In some forms, the
Cypris-stage immediately after the moult shows curious transitional
features between it and the Nauplius (Figs. 24 & 25); these inter-
mediate forms are important for the understanding of the structure of
the fully formed Pupa. In the latter (Figs. 26—28) the shield-shaped
carapace has assumed the form of a bivalved shell, open below for most
of its extent. The caudal spine and the horns are quite lost, and the
antennules have suddenly become transformed into a most remark-
able pair of prehensile organs of curious shape (a), provided with a
complex series of muscles (Fig. 27) to enable them to perform a
variety of movements. They are usually seen completely withdrawn

84 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

within the shell. The labrum is lost, as also are the great antenne,
while the mandibles are reduced to a pair of small jaws (mn.) All
the thoracic appendages have become external, and are each provided
with a pencil of long bristles, and perform swimming movements by
giving sharp jerks in unison. A good deal of the internal organi-
zation is obscured by the presence of a considerable number of oil
drops (0. g.), but many points may be made out in living and in
Canada balsam specimens. One can still distinguish the Nauplius-eye
(Vp. e.), while the compound eyes (¢. é.) are now well developed, and
can sometimes be seen to have a continual twitching movement.
The shrivelled stomach (s.) appears as a red spot (bleached in
mounted specimens) in the front part of the thorax. A powerful
adductor muscle (ad. sc.) runs from one valve of the shell to the
other, and just in front of this is seen a kidney-shaped glandular
structure (rn. gl.), the function of which is not clear; the same may
be said of a transparent oval sac on each side of the body near the
Nauplius-eye (Fig. 26). The thorax (th.) can now be completely
withdrawn within the shell by an important muscle (Fig. 24); when
protruded, the thoracic ganglionic chain (¢. g. ¢.) can be seen as a
conical mass just above the bases of the appendages. The Cypris-
stage no longer feeds, and shows little or no reaction to light, and
seems to pass its time chiefly in sporting at the surface of the
water.

The Cypris-stage of Balanus balanoides (Figs. 27 & 28) can be
distinguished by a number of points from the corresponding stage of
other Barnacles. Among the most readily recognized features are the
large size (1:11 mm. in length), and the pitted markings on the shell
(Fig. 18). The shape, too, differs from that of other species found on
our coasts. The anterior and posterior portion of each half of the
mantle are reddish and marked by a number of minute chocolate
coloured spots, and towards the hinder end on each side of the thorax,
is usually Gf not always) found an accumulation of minute greenish
yellow oil droplets (0. g.) The apertures of the fronto-lateral glands are
very small. (Compare Figs. 24 & 25 representing the immature Cypris-
stage of another species of Balanws which was obtained along with the
other by Messrs. Sinel and Hornell off Jersey). ‘This Pupa is smaller
(0'7 mm.) and more transparent than that of B. balanovdes, and has
no markings on the shell; the fronto-lateral apertures are tolerably
prominent. Another British species is shown in Fig. 26. It was
obtained in the surface waters of Plymouth in May, 1892: I am
unable to name even the genus of this form; it may perhaps belong
to Chthamalus stellatws, which is excessively common in that district.
It has an elongated shape and undulating contours, and is almost
colourless ; it has a number of small reddish brown spots principally

LIFE-HISTORY OF THE ROCK BARNACLE. 85

on the dorsal side in front and behind. It measures on the average
about 0°7 mm. in length..

After swimming about for a certain length of time the larva
becomes attached to the rock between tide-marks, and undergoes a
very remarkable series of changes which result in the production of
a form totally different in appearance from the Pupa. The appear-
ance of the young Barnacle when some time after fixation is shown
in Fig. 29; the shape and colour of the carapace has altered consi-
derably ; the changes during this transformation are very considerable,
and when the moult has taken place, and the cuticle been finally
thrown off, give the young Barnacle almost the form of the adult
(Fig. 20). The shell is marked by the same punctures (Fig. 21) as
were seen in the Cypris-stage. Further growth in size and some
change in the proportion of the parts gradually lead the young form
up to the adult.

(To be continued).

Notrt.—The Plate illustrative of Part II of this paper will comprise Figs. 21 to
29, references to some of which are made in the text.

EXPLANATION OF PLATE VIII.
Nawplius-stage of Barnacle.

Fig. 1. Side view of Nauplius of Stage II of Balanus perforatus.
Behind the brain (br.) are seen the circum-cesoph. con-
nectives and the sub-cesoph. ganglion. -

Fig. 2. Antennule of same.

Fig. 3. Antenna of same, with (gn.) gnathobase moved by a
powerful muscle (gn. m.)

Fig. 4. Mandible of same.

Fig. 5. Distal lobe of labrum showing the four unicellular glands

(ax. gl.)

Fronto-lateral glands of one side of same.

Striated muscular fibres of appendages, showing the muscle

corpuscle.

Fig. 8. Dorsal view of brain of same.

br. brain ; br. a. l. accessory lobes of brain; br. c. l. central
lobe of brain; ¢. 0. ¢. circum-cesophageal connectives ;
j. f. frontal filaments arising from spherical bases within
the brain; Np. e. Nauplius-eye imbedded between two
cushions of special sensory cells.

Fig. 9. Diagrammatic sagittal (median longitudinal vertical) section
through Nauplius belonging to Stage II; dnt. intestine
suspended by contractile fibres; gt. l. m. longitudinal

eZ
oe of
ID

86 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

muscular fibres joining intestine with hinder pocket of
stomach ; st. stomach with hinder pocket projecting below
intestine, the hind part of the stomach composed of high
striated deeply staining glandular cells; @s. cesophagus
suspended by contractile fibres and projecting into
stomach ; lbr. labrum projecting below mouth.

Fig. 10. Hinder part of tail (thorax-abdomen) of Conchoderma
virgata soon after first moult, to show telescoping of this
part.

Figs. 11—16. Ventral views of the six Nauplius-stages of Balanus
perforatus, drawn to scale, and showing some of the most
important differences. The appendages are omitted,
though their sockets are shown in Fig. 16.

Fig. 11. Newly-hatched Nauplius (Stage I).

Fig. 12. Stage II of same.

Fig. 13. Stage IIT of same.

Fig. 14. Stage IV of same.

Fig. 15. Stage V of same, showing segmenting thorax.

Fig. 16. Stage VI of same. The position of the mouth shows by
the transparency of the labrum (/br.) The first pair of
thoracic legs alone are shown in this figure, the remain-
ing ones being omitted for the sake of clearness.

Fig. 17. Cypris-stage of Balanus perforatus, ventral view; drawn
on same scale as Figs. 11—16.

Fig. 18. Portion of shell of same greatly magnified.

Fig. 19. Side view of Stage V of Nauplius of Balanus perforatus.
Behind the brain (br.) are seen the circum-cesophageal
nerve cords and the sub-cesophageal ganglion. The
stomach shows numerous oil drops imbedded in the wall
and is suspended like the cesophagus and intestine by
contractile fibres.

Fig. 20. View of very young adult form of Balanus balanoides
from above, showing valves of shell; s. scutum; ¢. tergum.

Lettering the same in all figures, viz:—a. anus; a. antennule ;

a”, antenna; a‘. s. socket of antennule; a2 s. socket of antenna;

a. d. m. dorsal muscles to appendages; br. brain; ¢. carapace; ¢. @

compound eye; ¢. 0. ¢. cireum-cesophageal connectives; c. s. caudal

spine; jf. f. frontal filament (olfactory); f. h. fronto-lateral horn ;

2. intestine ; lbr. labrum ; m. mouth; mn. mandible ; mm. s. socket of

mandible; mat. Ist maxilla; ma. 2nd maxilla; Np. e. Nauplius-eye ;

@. cesophagus ; o. g. oil globules; s. stomach; s. g. sub-cesophageal

ganglion ; ¢. tail (thorax-abdomen); th. thorax ; t. f. m. flexor muscle

of tail; ¢. U'. first thoracic leg; ¢ ¢ enlarged ectodermal cells of
tail (ventral plate).

~ Journ. of Mar. Zool.& Microscopy VOut. Wy il, WII.

SHiiisis lil

Set —y

THeEC. T. GROOM, Det. aD NAT.

THE DEVELOPMENT OF BALANUS.

THE DESCENT OF THE OCTOPODA,

A CONTRIBUTION TO A MORE NATURAL CLASSIFICATION.
BY E. H. L. SCHWARZ, A.R.C.S.

The Cephalopoda are usually now divided into the Tetrabran-
chiata and the Dibranchiata, terms which, though relying on a
character, viz. the number of gills, which must always remain
hypothetical in the vast majority of forms, nevertheless, till lately,
divided this group of Mollusca into two divisions, apparently
separated by a great gap.

The former group, except for a very few (83 or 5) species of
Nautilus, is extinct, and includes the animals of the camerated shells.
These are structures which, beginning from an embryonic protoconch,
are built up of a series of gradually enlarging chambers separate one
from another, except for a tube running uninterruptedly through
the whole, called the Siphuncle, which, according to Zittel,™ is the
remains of the visceral sac drawn out and now functionary as a
conveyor of nutriment to the distal parts of the shell.) In the
Ammonoidea the protoconch is inflated and calcified, and is usually
to be seen in carefully removing the matrix from the centre of well
preserved specimens: in the Nautiloidea on the other hand, it
appears to have been membranous, for no corresponding structure is
found except in rare cases of Orthoceras,@) but we infer that it must
have once been present by the occurrence of a scar or cicatrix on
the apex of the shell, showing the place where the embryonic shell
opened into the first true chamber.) Besides this distinction in the
protoconch, the Ammonoidea are distinguished from the Nautiloidea
by the complex folding of the wall or Septum separating two adjacent
chambers, and which forms the suture line on the exterior, being
always bent away from the mouth on the external (ventral) side,
forming a median lobe; and also by the siphuncle being placed on
the external margin of the shell, a character however which is broken
in Clymenia, which has the siphuncle internal.

The Nautiloidea are first met with in the lower rocks of the
Baltic Cambrian, occurrmg in a sandstone round St. Petersburg,
together with Olenellus, Cystideans, &c.,) in the form of a small
Orthoceras, (Volborthella). In the Ordovician, a great number of

(1). This has recently received fresh support from the work of Dr. G. Holm on
Endoceras. Dames and Kayser’s Paleont. Abhandl. Vol. III, 1885.

(2). Edwards and Wood, Hocene Mollusca, Pal. Soc. Mon., 1849, p. 12.

(8). Hyatt, Arietide, Mem. Mus. Comp. Zool., Harvard, 1889, p. 10.

(4). Hyatt, Embryology, Foss. Ceph., Bull. Mus. Comp. Zool., Cambridge,

Vol. ITI, 1852.
(5). Schmidt, Quart. Journ. Geol. Soc., Yol. XXXYIII, p. 516.

88 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

genera and species spring into existence; while in the Silurian this
division reaches its maximum developement; in the Trias, the
straight Orthoceras forms become extinct, while the coiled forms
continue in decreasing numbers through the succeeding strata to
the present day.

The Ammonoidea are first found in strata which Barrande
correlated as Silurian, but Kayser has recently made these beds
equivalent to the Hercynian, or lower Devonian.

The early forms belong entirely to the Goniatites ; in the upper
Devonian the puzzling Clymeniade appear, only to die out soon
after. In the Permian beds of the Artinsk region in the Urals,®
the Salt Range of India,” and Texas, Nebraska, &c., the last of the
Goniatites and the first of the true Ammonites appear. In the
Trias the latter become important constituents of the world’s fauna ;
and by their apparent sensitive natures, unable to withstand alter-
ations in their surroundings, form not only important zone fossils,
but have even been used as tests of Climate(): thus we get in the
Jurassic rocks on either side of the equator, the delicate Phylloceras
and Lytoceras in great abundance; in the northern latitudes, how-
ever, these two genera are never found, while sturdy forms lke
Cardioceras, take their place. In the Cretaceous, many of the
Ammonites become curiously modified as if trying to withstand the
new order of things by taking fantastic shapes, such as the hooked
Hamites, the straight Baculites and Ptychites, the loose spirals like
Pictetia and Crioceras, &c., while some of them returned to the
ancestral Triassic types, such as Buchiceras. A similar story occurs
in the Juvavian province of the Trias, whose beds were probably laid
down in a sea gradually drying up; here there occur the aberrant
Choristoceras, Rhabdoceras, and Cochlioceras, paralleling respec-
tively Crioceras, Baculites, and Turrilites of the Chalk. In the
uppermost Chalk (Danian), the Ammonites cease, though an Am-
monite and a Baculite from Chico Creek in California have been
referred to the Kocene.(®)

The Dibranchiata first appear in the rocks as the Belemnoidea,
recently traced as descending from Orthoceras through the Triassic
Aulacoceras.(!) These consist of a “ phragmacone” similarly

(6). Karpinsky, Sur ’Amm. Fauna Artinski, Mélanges géol. et paléont. trés du
Bull. de Acad. des Sci., St. Petersburg, Vol. I, 1890.

(7). Waagen, Salt Range, Fossils. Mem. Geol. Surv. India, 1879.

(8). Neumayr, Ueber Climat. Zonen der Jura und Kreide, Denkscrift Akad.
Wien, Vol. XLVII, 1883.

(9). Trask, An Ammon. and Baculite from Chico Creek, California, Acad. Nat.
Sci. Proc., Vol I, p. 92, 1856; also Heilprin, Ammon. in Tertiary Rocks, Philadelp.
Acad. Nat. Sci. Proc., Vol. 34, p. 94, 1882.

(10). Mojsisovics, Mediterran, Trias Prov., Abh. der K. K. Geol. Reichs, Wien
Bd. X, 1882,

DESCENT OF THE OCTOPODA. 89

shaped to a brevicone Orthoceras, round which is deposited a strong
calcareous “guard” prolonged backwards as a cylindrical rod and
enclosing and preserving the naturally caducous protoconch (hence
Bather’s suggested name “ Coleoidea ” for the Belemnites and their
derivatives).21) In front, the sheath of the phragmacone rises up to
form the thin pro-ostracum, which probably held up the manile.
The Belemnoidea commence in the upper Trias of the Alps, and
cease in the top of the Chalk, attaiming their maximum in the Lias.

Representatives of the Sepiadee and Teuthidee are first met with
in the Lias, but owing to the fragility of their shells, they are only
found under exceptional circumstances. The shell of the ordinary
Cuttle-fish is possibly a modification of the Belemnite structure(!”) ;
the phragmacone becomes hypertrophied, and instead of a succession
of well marked septa there arises a spongy tissue of innumerable fine
calcareous lamelle ; the pro-ostracum remains as before; and the
guard dwindles away to a small peak. In Loligo, all calcareous
matter has disappeared from the shell, and only a chitinous structure
occurs. Then, till recently, the shell sac was supposed to abort
completely, and the Octopoda arose without any calcareous skeleton
whatever.

Everything would fit in nicely if the female of one of the
Octopoda, viz., Argonauta, the paper Nautilus, had not an external
shell. This structure was regarded merely as an accident; was
formed by the arms and not by the body at all; and was considered
in no way homologous with the external shells of the Ammonites and
Nautili, because it was not camerated. But Hyatt(l5) has shown
that half of it is formed by the body-mantle; Stiss(!4) and Stein-
mann(15) have shown that it closely resembles some of the Cretaceous
Scaphites in outer shape; while the consideration of how the
chambers of the latter are formed, shows that the absence of these
is no essential at all. For the shell of all Ammonites and Nautili is
formed of an outer porcellanous or granular layer, and an inner
nacreous or prismatic one, the latter also forming the septa. To
produce this nacre, it appears necessary that the mantle should be
wholly occupied with that function; but in the Argonaut the mantle
surface bears chromatophores, and hence is used for other purposes
than secreting the shell; therefore, all the parts represented in the

(11). Ann. Mag. Nat. Hist., 1888, p. 302.

(12). WVoltz, Mém. Soc. Hist. Nat. de Strassbouwrg, Vol. I, p. 1, 1830; see also
F. A. Bather, loc. cit.

(13). Embryology, Bull. Mus. Comp. Zool., Vol. III.

(14). Ueber Ammon., Sitz. ber. der Wien Akad., Bd. LII, p. 71, 1866; 7b. LXTI,
p. 805, 1870.

(15). Vorlauf. Mittheil. u. d. organiz. der Ammon., Ber. Naturforscher Gesell.,
Freiburg, Vol. LV, 1889,

90 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

true camerated shells by the nacreous layer, must necessarily be
absent, though the design of both is the same. Again, the complex
foldings of the Ammonite septa show that they were formed from a
very loose mantle, and being curved forwards instead of backwards,
as in the Nautili, the membrane must have been blown out from
behind while it was depositing the shell: also where the siphuncle
passes through the septa, the little funnel around it there, is turned
forwards, as if sticking into the animal. Hence we must conclude
that the mantle, before it secreted the septum, must have been
distended with something which at the time of the secretion had
disappeared, and the mantle was blown forwards to take up its space,
for useless superabundance of mantle is inconceivable. The only
suggestion that can be offered, is that this something was eggs,{(16)
which, accumulating in the hinder portion of the animal, forced it
forwards; when the full complement was laid, and they became
extruded, the mantle secreted gas on its outer surface, which blew
it out to take the place left empty; but where the internal organs
had once pressed firmly, the mantle adhered to the shell, and a series
of festoons were formed which ultimately became translated into the
lobes and saddles of the particular species of Ammonite.

The animal cannot have moved forwards merely to obtain more
body space, for in Arcestes, for instance, the rate of increase is so
minute, that each living-chamber is inappreciably larger than the one
before. Also there would in that case be a drag on the fleshy
Siphuncle, which, when the shell was secreted around the proximal
part must have formed a backwardly directed funnel; but on the
supposition that the animal was forced forwards by the eggs, the
siphuncle would have time to permanently stretch, and the gas
would then be able to press it up to its insertion in the body wall
and a forwardly directed funnel come to be secreted.

No such structure as these complicated suture lines could be
found in a male, whose spermatozoa do not take up anything like the-
space that ova do, which m the Cephalopoda generally contain an
enormous amount of yolk.

Thus we get an additional probability that the Argonaut is
‘closely allied to the Ammonites, since the shell in both is only
possessed by the female. Munier-Chalmas(!7) and Haug,(18) however,
have discovered series of Ammonites of which one is characterized
‘by their large size and simple mouths, and another consists of small

(16). Tate and Blake, Yorkshire Lias, p. 263, 1876.

(17). Munier-Chalmas, Sur la possibilité d’admettre un dimorphisme sexuel
chez les Ammon., Comptes-Rendus Sommaires, Bull. Soc. Géol. France, 1892,
p. clxxiy.

(18). Haug, Etudes s. 1, Ammon, Juras., Bull. Soc. Géol. France, Vol. XX, 1892.

DESCENT OF THE OCTOPODA. 91

forms with lateral ears to the mouth, while in other characters they
are similar, suture line, ornaments, &e.; hence they conclude that
the large ones are the females, and the small, males. But since the
lobings of the Septa must be determined by the position of soft
parts, and it is impossible that the female with her complex sexual
apparatus should produce the same septa as a male with his com-
parative simple one, it seems inevitable that we must call these
forms different genera, as Zittel does,) such as Oekotraustes and
Oppelia.

If this view be true that Argonauta is closely allied to the
Ammonites, (and it has been gaining sensibly in favour in the last
few years, for we find the Ammonites set down as Dibranchs in the
“ Zoological Record,’) then Owen’s group Dibranchiata includes a
direct “mutation” (to use Prof. Blake’s term)(2) of the Ammonites,
and highly specialized “ divergents” of the Nautili (Belemnites, &c.) ;
so that the division has now become artificial and strained. And not
for this reason alone.

In the Dibranchiata, the skin is richly supplied with blood
vessels, and a considerable amount of cutaneous respiration goes on,
so that the least possible number and size of gills is required to keep
the blood in its normal condition; but in animals enclosed on all
sides with a shell, a greater gill-surface will be required. This may
be obtained cither by increasing the number or size of the gills.
Since the only living Nautilus has done the former, it is probable
that the Ammonites did the same, and, possibly to a larger extent.
In Arcestes, for instance, we get a body chamber over one whorl in
length, and in some cases approaching two, the aperture is very
narrow, and the chamber low and flat; here there would not have
been room for two large gills of the requisite size, or even four, but
there might easily have been a row of several pairs of small branchie.
Therefore there seems as much reason to class the Ammonites and
Nautili with long chambers as Multibranchiata, as the conventional
Tetrabranchiata.

However, the number of gills must always remain hypothetical
in these extinct forms, and a new division with new names seems
desirable. Foord(?!) and Blake(22) have taken Mr. Bather to divide
the Cephalopoda into the Ammonoidea, Nautiloidea, and Coleoidea,
though he himself seems to restrict his new name to the Belemnites.
However the two first groups are bound together by so many bonds
of similarity, that it seems unwise to separate them, especially as

(19). Handbuch der Paleontologie, Ba. II.
(20). Presidential Address, Geol. Assoc., 1893.

(21). Brit. Mus. Cat. Cephalop., Vol. 1, 1888, p. 10.
(22). Ann. Mag. Nat. Hist., 1888, p. 377.

92 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

long custom has united them under the old term Tetrabranchiata..
Hence I propose the division of the Cephalopoda into the Endo-
cochlia and the Ectocochlia(™ ; the first including the Belemnitide,
Sepiade, Teuthidee, and Spirulide ; while the second includes the
Nautiloidea, the Ammonoidea, and the Octopoda. This division not
only agrees with the trend of recent investigation, but also has the
merit of relying on a character which can be actually examined in
fossil, as well as recent animals.

P.S.—Since the above was written, my attention was called to a
paper by MM. Perrier and Rochebrune, (Comptes Rendus CXVIII,
p- 770), in which they describe a new Octopus (0. dignati) from
California, which deposits its eggs within the shells of bivalves
(Cytherea and Pecten) and not only so, but itself gets into the shell
and remains there during incubation, and possibly longer. This may
be taken merely as a specialization of the ordinary habit of European
Octopi which utilize in ike manner the crevices of rocks, and any
other hollow, as has been described by Aristotle, Lee, &c. But it
seems more likely to be a return to former habits. The Octopus in
the process of loosing its ammouitic shell, passed through a stage in
which some retained their original covering while others were free ;
some of the latter, then, during the sexual period, would feel the loss
of the shell which their near relatives possessed, and like the hermit-
crab, would take to their cast off shells if they could find them, or,
in default, any shell that came handy. From these are descended
the Californian species. Others, under peculiarly luxurious sur-
roundings lost the habit of covering their body altogether, and when
harder times set in, only a vague reminiscence of the instinct
remained, and they sheltered their eggs in any convenient hollow.
On any other hypothesis than the derivation of the Octopoda from
the Ammonites, the incubation of the Octopus is an inexplicable
mystery.

(a). «Tos, without; éyros, within ; “OX AOS, a shell.

Ponps anp Rocx-poors.—Under this attractive title, Mr. Hy. Scherren has
gathered together, in pleasant form, many valuable notes on the smaller life that
swarms in tiny tidal reservoirs and among the weeds of country ponds. The book
is just what such a work should aspire to be, and will be read with thorough
enjoyment by all true Nature-lovers. And while popularly written, the author
sacrifices no scientific truths, and draws upon personal experience in all things.
The price of this little work, which is published by the Religious Tract Society, is
extremely moderate.

MICROSCOPICAL STUDIES IN MARINE ZOOLOGY,

BY JAMES HORNELL.

Strupy X.—TypicaL ALCYONARIA.

The general characters of the central or typical form of these
colonial Anthozoa, have already been dealt with in outline in the
preceding note, and it therefore only remains to fill in some details.

Two species of Aleyoniwm are found comparatively plentiful in
European seas; the one, A. digitatum, stout and massive, with few
or no branches; the other, A. palmatum, slender, arborescent, and
with fewer, but larger polyps. Normally the colonies of both species
are found attached by an extended base, but instances are known
where A. digitatum occurs in free, ball-like masses.

The latter species is usually snowy white, but occasional pale
orange coloured varieties are found, the tint being due to the dif-
fusion of colour throughout the cellular tissue. A. palmatum on
the other hand, has very frequently a well marked variegated rosy
hue, extremely pretty and not affected at all by the extractive action
of alcohol. Curiously this is due to certain of the superficial spicules
containing iron oxide. The bright red tints of the fiery Pennatula
(Sea-pen) are due to a similar cause, and more important still, to
this is also due, the colour that gives commercial value and beauty
to red coral.

In many ways these spicules are of great interest. Their shape
and arrangement, in conjunction with the form of the colony, furnish
the principal guides to the classification of the group. In A. pal-
matum there are five principal forms: (a) those of ruddy hue and
the largest in size (s4o-in. long), are arranged in eight bundles at the
bases of the tentacles. The spicules in each of these bundles con-
verge from right and left, and form a strong framework support for
the free extremity of the polyp. The shape of each spicule is that
of a stout bent rod, tapering abruptly to a rough point at either end ;
warted too, but much less prominently than any of the others to be
mentioned. The foregoing pass at the apex of each bundle into
those (6) that act as the supporting skeleton of the tentacles. Their
general shape is rather more irregular, they are colourless, shorter,
and the warting is much stronger. Size sés-in. (c) A dense irre-
gularly disposed layer crusting the general surface of the colony,

94, JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

consists of small, strong-spiked straight rods sés-in. long. Most
peculiar forms are sometimes assumed, due to the great and irregular
development of the spines; being sometimes broadly bilobed, some-
times even trifid. (¢) In the interior of the colony, in the stiff
mesoglea that divides and yet joins the different polyps, scattered
spicules, very slightly spined, and nearly straight, occur; while a
fifth form of spicule (d) cecurs in the thick wall of the cesophagus.
These last are the smallest of any in the colony and barely measure
so0-1n. long.

In Alcyonium digitatum, the spicules differ very charac-
teristically from all the preceding, in their much greater profusion,
in their greater massiveness, and in their peculiar shape. The rod-
like form, so closely adhered to in A. palmatwm, is here nearly
obliterated, and the spicules are cften irregularly branched, and all
the limbs beset by enormous wart-spines. (Fig. 3).

In the Organ-Pipe Coral (Yubipora) the spicules of the mesoglea
surrounding cach individual, become locked firmly together by
numerous minute serrations, and form perfect calcareous tubes. In
the Red Coral of commerce, (Coralliwm rubrum), on the other.
hand, a strong central stony axis is formed by an even more intimate
association of the spicules of the axis of the colony, due to an actual
cementing together of these timy limy rods. In Z'ubipora the polyps
can retract within their protective tubes, but in the Red Coral
there is scarcely any provision for the retraction, for safety, of the
polyps.

As in the Anthozoa generally, so in Aleyonium the sexes are
separate; indeed even the sexes of different colonies are distinct ;
the individuals in any one commonwealth are thus either all males,
or else all females. The ova and the sperm masses are borne on
little stalked capsules upon the free edges of the mesenteries, and
development takes place outside the parent. The embryos are free
swimming by means of a complete investment of lashing threads
or cilia; a little while they sport thus amid the waves, and then
affix themselves to some rock, and by continued budding produce
extensive colonies.

Note the very large size of the hollew pmnate tentacles, and the
thickness of the walls of the cesophagus (st.) Below the latter, the
upper parts cf the mesenteries are very apparent because of their
greatly convoluted and thickened margins (PI. x, Fig. 1, m. f.); from
this point downwards, the mesenteries decrease rapidly in prominence,
and soon show us very slight ridges only. The two dorsal ones
are of greater length than any of the others, 2.e., descending lower
down the gastric cavity, and whereas their thickened edges or
mesenterial filaments (craspeda) are composed of strongly ciliated

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ALCYONIUM AND LARVAL ASCIDIANS.

EXPLANATION OF PLATE X.
Figs. 1 to 3, Aleyonaria.

Fig. 1. Single polyp of Alcyoniwm palmatum, greatly magnified.
st. Stomodeum or csophagus; mes. mesenteries; .f.
mesenterial filaments or craspeda; g.c. gastric Suis
s.s. supporting spicules.
la, a spicule from lower end of a tentacle; 1b, a supporting
spicule; 1c, some of the superficial-lyig spicules that
form the protecting cortex of the colony; 1d, spicules
from the supporting lamella of the stomodeum; le, a
spicule from the deeper’ parts of the mesoglea.
Fig. 2, A branch of Aleyonwum, with polyps in various stages
of expansion. x 2.

Vig. 3. Spicules from mesoglea of Alcyonium digitatum.

Figs. 4 to 6, also A to D, Larval Ascidians.
Fig. 4. A tadpole larva of Aplidiwm elegans (Giard), just freed

from the parent. . Viewed from left side.
Fig. 5. Diagram of the structure of a similar larva, seen from right
side.
Fig. 6. Diagram showing stages in the metamosphosis of a tailed
larva into the adult sessile condition.
‘Fig, 7. <A colony of Aplidium elegans, when in adult stance :
natural size ; ¢.c.o. common cloacal orifices.
Figs. A to D, Larvee where the papille are abnormal in number or in
arrangement. ee gr, Gara
Lettering the same in all figures, viz :—a. atrium; a.o. atrial or
cloacal orifice ; ap. adhesive papille ; c.v. cerebral vesicle ; ¢.n. candal
nerve ; br. c. branchial or pharyngeal clefts; en. endostyle; g. gan-
glion; g.s. cells homologous to the fadimeney gemmiferous tubules
of other species, which give rise, by growth and budding, to new
individuals, when the larva becomes attached, and proceeds to form a
colonial mass (fide Giard); 0. mouth ; oe. cesophagus ; nt. notochord ;
ph. pharynx ; st. stomach.

EXPLANATION OF PLATE XI.
Polynoé propinqua, one of the higher Annelida.

Fig. 1. Optical section of an individual viewed from above, the
elytra having been removed.
Fig. 2. Appearance of the animal with elytra in place—life size.

ee
a.
ist)

. View’ of head and its appendages.
Fig. 4. Anterior portion of body showing the extruded proboscis,
bearing at the extremity a ring of papillae, and having
four pairs of horny jaws (2 only visible here) just within
the orifice. -

FE ig. 5. An individual showing regeneration of the hinder end,
after a breakage that had taken place at the point
marked *, _ |

Fig. 6. Diagram of a transverse section of a somite bearing dorsal

| cirri.

Fig. 7. Diagram of a similar section through an elytra-bearing
somite. These two figures are useful in the understand-
ing of the possible origin of elytra from dorsal cirri,

Fig. 8. <A parapodium or foot.

Fig. 9. A dorsal or notopodial bristle.

Fig. 10. A ventral or neuropodial bristle.

Fig. 11. An elytron or scale, showing the row of globular enoercles
around the outer margin.

Fig. 12. Edge of same highly magnified, to show one. of these

tubercles.

Fig. 13. A portion of an elytron sill more highly magnified, to
show the fine papille of the surface.

Lettering the same in all figures, viz:—a.c. anal cirri; act
aciculum of Ist somite ; acd. aciculum of notopodium or dorsal branch
of foot ; acv. aciculum of neuropodium or ventral branch ; cae. caecum
of alimentary canal; d.c. dorsal cirrus; el. elytron; el. ped. peduncle
of elytron; int. intestine; m.a. median antenna; nr. notopodium or
dorsal branch of foot; np. neuropodium or ventral branch; ph.
pharynx; ph. t. pharyngeal teeth; p. palp; pr. prostomium; s.l.a.
supero-lateral antenna; t¢.c. tentacular cirri; v.c. ventral or neuropo-
dial cirrus. ;

Journ. of Mar. Zool. & Microscopy WOits Il, IP, 2M.

JaS. HORNELL, DEL. aD NAT
JERSEY BIOL. STN.

THE ANATOMY OF POLYNCE PROPINQUA.

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MICROSCOPICAL STUDIES. 95

cells derived from the downgrowth of two lines ef cells from the
lining of the cesophagus (ectoderm cells*), the thickened edges of the
remaining mesenteries are less ciliate and their cells are endodermal
in origin. By the combined action of the cilia of the two dorsal
mesenterial edges, an ascending current of water is kept in motion.

The gastric cavities of the zooids are sometimes very long,
extending downwards along the axis of the colony for several inches.
Those of adjoining zooids are put into communication by a network
of fine ramifying tubes, buds from whose walls produce the fresh
zooids of the commonwealth. ;

The group Alcyonaria is of some importance geologically. Thus
Syringopora of Paleozoic times was probably allied to the Organ-
Pipe Coral (Tubipora). The common fossil Favosites was also an
Alcyonarian, while Coralliwm has been found in the Jurassic rocks.

Stupy XI.—THE LIFE-CYCLE oF OBELIA GENICULATA.

A few weeks since, a friend in the North of England was good
enough to send me some living specimens of a Zoophyte not found in
Jersey waters. Confined in a comparatively small jar, the somewhat
unnatural conditions had apparently hastened the birth of the
developing reproductive buds, and these were swimming freely in
the water as so many rythmically pulsating salver-shaped jelly fishes
of the most wondrous transparency and delicacy of form. A circlet
of regular and rather short thread-like arms stood out from the
margin, while upon the dise could just be made out, with the aid of
a lens, two intersecting lines with a handle-like stalk pendant from
the point where these two lines crossed. And the tiniest pin’s head
was not larger in size. Some were born before my eyes from ovate
sacs in the branch axils of the Hydroid parent.

Very generally the Hydrozoa, to which the neck of our
sketch belongs, present well-marked instances of that many phased
strange phenomencn, known familiarly as Alternation of Generation.
At one period living attached to rocks, or weeds, or shells, under
the form of tiny anemone-like animals, they often form by a con-
tinued process of budding, a shrub-like colony of many individuals.
This is termed the Hydroid Stage, from which arises by budding
and fission, free-swimming individuals or Medusezs—the true sexual

* Ketoderm and endoderm are terms of extreme importance. The embryo very
early in its history consists of two layers of cells, an outer ectoderm and an inner
endoderm, between which develops quickly a third, the mesoderm. All succeeding
tissues owe origin to one or other of these, and roughly we may take it that
epidermal tissues have ectodermal origin; the alimentary canal and its offshoots

being lined with endoderm, while muscle, connective SSE &¢., are of mesodermal
origin. s

96 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

stage. The sexes are separate, some producing ova, and some
spermatozoa. The resulting embryos—tiny things that progress by
rhythmic lashing of cilia—attach themselves after a short period of
activity to some fixed object and soon develop into tiny Hydra-like
creatures, to circle once more with absolute fidelity through the
strange alteration of stages gone through by innumerable multitudes
of progenitors.

Seldom are these two great Life-Phases at all equal in size-
importance. One is nearly always magnified at the expense of the
other. One usually sinks into insignificance, slurred over and fre-
quently even entirely suppressed. And according to which phase is
magnified, have we one of the principal points characteristic of one
or the other of the two sub-classes of the Hydrozoa. If the free-
swimming sexual or Medusid-stage be the chief life-form, and the
Hydroid be all but suppressed, then we have the division of the
Scyphomeduse—the Acelephe of some writers. Herein are in-
cluded all the large Jelly-fishes so familiar in summer time on our
coast, during warm weather, and moving at times in shoals of
immense numbers. The other division is that where the Hydroid-
stage is exaggerated and usually colonial, and where the Medusid or
swimming stage is tiny or even eliminated. Such constitute the
Hydromeduse which are further distinguished from the Scypho-
medusz, in that the Medusze of the former have the edge of the bell
turned horizontally inwards forming a delicate veil, the velum,
partially closmg the mouth of the bell. This character constitutes a
Craspedote Medusa, as contrasted with the Acraspedotes form of the
Scyphomeduse, where the velum is absent.

The Hydroid Zoophytes, or Hydroidea, constitute the central
order of the Hydromeduse, and possess the typical life-history. In
passing it is well to remember that besides the Hydroidea, there are
two other orders, viz., the Trachymedusee and the Siphonophora, both
characterised by pelagic habit, and the fact that they never have a
fixed or stationary hydroid phase.

The Hydroidea show much variation in the form of their Hydroid
stage and in the completeness of their life-history. Obelia is
very typical of unabbreviated life-cycle, so is specially useful to
use as an introductory type for study. The colonial stage is
remarkably beautiful, its delicate zig-zag branches forming dense
miniature forests on the broad brown oar-weed. An old writer
speaking of a nearly related and not more beautiful species, says,
“ Delicacy, transparency, and grace pervade the entire structure ; the
spirit of beauty has thrown itself into every curve and line: the eye
rests, with full satisfaction on the little cups, so perfect in their form ;.

MICROSCOPICAL STUDIES. 97

and hardly less beautiful are the ringed and twisted pedicles that
support them.”

The colony is protected in all its parts by a delicate transparent
horny substance—the perisarc, and consists of a zig-zag stem, jointed
at each curve, and giving off on alternate sides, a short ringed pinna,
bearing aloft a tiny crystal cup (hydrotheca or calcycle), wherein
lodges an equally tiny polypite or hydranth (PI. ix, Fig. 2, p.), armed
with a well-marked proboscis and numerous tentacles. To the polypite
is delegated the sole duty cf capturing prey. The whole organism is
the truest of commonwealths ; each polypite captures not for its own
sustenance only, but equally for the whole colony, for the base of the
body of each individual passes into a tubular prolongation, ceenosare,
continuous with a similar tubular tissue in the main stem. If one
polypite capture food, part of the products of digestion pass into the
tubular ccenosare, and is conveyed to neighbouring parts of the
colony for purposes of nutrition. And upon this unselfish mutual
help, depends the power of the colony to set free from the purely
nutritive (vegetative) function, certain individuals or zooids, charged
specially with the reproduction of the species. These specialized
zooids are developed in the axils of the branches and are elegant
clongated urns in shape, gonothece: (g), wherein the ccenosare breaks
up into granular bud-shaped masses that gradually evolve into
transparent delicate swimming-discs. Their gracefulness has to be
seen to be understood. One has to watch them as, so many streamer-
decked bells, they sink slowly through the water, of a sudden to
regain activity and pass upwards by a series of vigorous jerking
pulsations, to cease after a number of strokes and become inert,
slowly-sinking parachutes once more.

Meduse are generally bell-shaped, with the true edge turned hori-
zontally inwards to form the velum (Fig. 5, v.), but in the form under
notice, the shape is nearly that of a flattened disc, and the velum in
consequence of this difference is all but absent. From the apparent
edge of the disc proceed a number of tentacles beset with stinging
cells, while from the centre depends a tubular process, the manubrium
(m.), having the mouth at the free extremity and a slightly dilated
cavity, the atrium (q.), at the attached base. From the atrium proceed
four radial canals (rc), while around the edge of the disc, just inside
the ring of tentacles, is a circumferential canal (c.c.), into which the
radial canals empty. All these cavities are lined with ciliated endo-
derm, which shows little divergence in form in the various regions.
The ectoderm forming the exterior coat of the Medusa exhibits much
more differentiation; while on the upper surface it consists of flat-
tened cells, on the under it developes radially disposed muscle fibres,
and on the manubrium, longitudinally disposed ones. Between the

98 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

ectoderm of the upper surface of the disc,and the endoderm of the atrium
and radial canals, is the intermediate body layer, the mesoglea. In
Obelia, it is thin, but in some species it is often enormously developed
as a thick jelly-like substance (Aurelia, Pelagia, &c.), that gives
cause to the popular name of the Medusee. The term umbrella (w.), is
bestowed upon this layer. The sub-umbrella (s.v.), another layer of the
same tissue, but quite thin in even the best developed instances, is
found between the endoderm and the lower surface of the animal.
A point sometimes overlooked is that the radial canals are joined
together by a horizontal layer of endoderm cells, so that where the
umbrella and the sub-umbrella are not separated by an endoderm-
lied space (atrium or canals), they are by a solid layer of endoderm
cells.

The tentacles are here solid, consisting of a single row of large
endoderm cells encased in a layer of small ectoderm ones, which
develop numerous stinging cells.

Eight so-called “ otocysts ” (ot.) are found on the inner side of the
bases of certain of the tentacles. Each consists of a sac containing
an otolith. The function has long been supposed to be auditory,
but Hurst (Wat. Se., June, 1893) has with much plausibility argued
for their true use as organs designed to give warning of approach to
an unquiet, wave-disturbed region, in the turmoil of which their frail
anatomy nught suffer. (The thick umbrella of some contams up to
957, to 987 of water !)

The sexes are separate. In Qbelia, the genital glands (gg.) are
developed as four masses upon the radial canals, one for each midway
between manubrium and margin. The ova after fertilization become
ciliated embryos, which soon affix themselves and develop into
hydroid colonies.

It is painful to have to record that these timy marvels of
Nature’s excellence of workmanship, are sordidly greedy and vora-
cious. The power of the sting-cells has great paralysing action and
comparatively large animals are easily captured, and sucked into the
mouth. Fig. 6 shows how an Arrow-worm (Sagitta) had been
captured and partly doubled in two and so partially swallowed.
Copepods, notably Temora, form another common focd.

Obelia, save in the slight development of the velum of the
Medusa, and the form of the latter being rather that of a dise than
bell-shaped, is thoroughly typical of the form and development of
that division of the Hydroidea where the polypites are borne in
cups—the Calyptoblastic Hydroidea.

Endless and complicated modifications exist in other species,
and some of these I hope to illustrate and explain before long.

Journ. of Mar. Zool & Microscopy V ors lees:

JaS. HORNELL, DEL. AD NAT
Jersey Biot. Stn.

TEE LIFE-HISTORY OF OBELIA GENICULATA,

MICROSCOPICAL STUDIES. 99

EXPLANATION OF PLATE IX.
Tife-History of Obelia geniculata.

Fig. 1. Natural appearance of the fronds of the Hydroid-stage, as
they grow upon the surface of Laminaria. Life size.

Fig. 2. A single frond of the same much enlarged. pr, perisarc ;
e, coenosarc; h, hydrotheca;-p, polypite: b, bud devel-
oping to form a polypite later on (note that the perisare
covers the entire surface of the bud; as growth goes on
a thinning takes place at the apex, and finally gives way
to permit of the extrusion of the polypite’s tentacles) ;
g, gonotheca; m, medusid buds in different stages, within
the gonotheca.

Fig. 3. View from below of a freed medusa.

Fig. 4. Diagram of same.

Fig. 5. Diagrammatic vertical section through same. The section
follows the course of a radial canal on the right side,
while on the left, an interradial portion of the disc is
sectioned.

Fig. 6. A Medusa, considerably older than that shown at Fig. 3,
seen reverted and from the side. It had just captured
an Arrow-worm (Sagitta), which is doubled up, the bend
being within the digestive cavity of the Medusa.

Lettering the same for Figs. 3—6, viz :—a, atrium ; ¢.¢, circum-
ferential canal; en, endoderm; g.g, genital glands; m, manubrium ;

0, mouth; ot, otocyst; 7.c, radial_canal; s.w, sub-umbrella; ¢, ten-

tacle; w, umbrella; v, velum. —

Stupy XII—On PoLyNo# PROPINQUA AS TYPICAL OF THE
HIGHER ANNELIDS.

Polynoé propinqua (Malmgren) is an elegant marine annelid,
short and slender in its proportions, rapid ‘and lively in its movements.
When the tide reecdes, its haunts are to be found wherever boulders
litter the shore, and many a weary backache have I had through a
course of such stone-turning. It is easily recognized by reason of
two rows of oval overlapping brownish scales that lie upon its back,
and from under which project, car-like, on either side, serried banks
of lovely translucent paddling-bristles. A pretty creature, but loath
to be captured. Alarmed at the approach of the forceps, it squirms
and makes desperate effort to escape, and indeed if it be lifted
roughly and by force, instead of being taken by some gentle snare,
lo! it breaks into pieces and is to you but a worthless capture.

100 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

A cursory examination suffices to show that except for the two
extremities, the body is divisible into about 41 ring-like portions, all
broadly or obviously of the same value one with the other—formed
fundamentally upon the same plan, though some are either internally
or externally modified in particulars for special functions. The
typical form of these equivalent body-rings, or somites as they are
termed, possesses on either side a fleshy two-branched lobe, the
parapodium, in which are implanted bundles of finely sculptured
bristles or sete. The upper branch, the notopodium, is considerably
smaller than the ventral or neuropodium, and its sete are shorter
and of a different pattern to those of the latter. The drawings
on Pl. XI sufficiently illustrate the general arrangement and the
details of divergence. Besides the ordinary sete, cach branch of the
parapodium contains a single stout spine, aciculum, buried, all but
the point, in the flesh.

The form of the parapodia—often termed rather loosely the
feet—and of their bristles, is remarkably stable throughout the whole
length of the body, excepting only in the case of the first somite, the
peristomium, the one bearing the mouth. Here cach parapodium
is reduced to a long slender lobe, obscurely divided into rudimentary
upper and lower branches, and with but one aciculum and two or
three tiny sete.

The tactile appendages garnishing the various somites show
much divergence. Thus the somites 2, 4, 5, 7, 9, 11, 18, 15, 17, 19,
21, 23, 26, 29, 32, bear each one pair of the characteristic scales, or
elytra, while the remaining ones bear on either side a long filiform
appendage, the dorsal or notopodial cirrus, arising from the base of
the notopodium. Reference to Fig. 1 will explain this arrangement
and show how, in the major part of the body, these two organs
roughly alternate, giving place in the last ten somites to cirri only,
thus leaving this short portion naked. The neuropodium bears also a
short ventral cirrus, but this shows no variation except in the
peristomium, where it is greatly elongated.

In structure, the elytra are thin membranous two-layered ee
borne on broad low peduncles, and so loosely attached, that it is
extremely difficult to obtain a preserved specimen with the full
number present. This extreme looseness is peculiar to this species.
In others, such as the common Lepidonotus squamatus, they adhere
with such firmness that they frequently tear rather than lift off, and
between these two extremes, there is every intermediate degree.
The surface of the scale is prettily marbled, while around the exposed
- edge is a row of all but globular tubercles, very diagnostic of this
species. Occasionally I have noticed the elytra to be distended in a
bladder-like manner, Some observers have supposed this to be an

MICROSCOPICAL STUDIES. 101

incubatory device, as they have found them filled with ova. This
however does not necessarily follow, for the ova when freed, find their
way into all the spaces of the body-cavity, and of this, the hollows of
the elytra are but offshoots.

Probably elytra are modifications of certain dorsal cirri—the two
never being found co-existent upon the same somite in Polynoé,
though in Sigalion, a scale-covered worm of great length, they do
exist together. In the latter case however, the common phenomenon
of duplicative variation (see Bateson’s “ Materials for the Study of
Variation”) has probably been at work; if so, then Polynoé shows
regular modification from a form possessing dorsal cirri to every somite,
while Sigalion shows such modification with duplication superadded.

The head, the prostomium, consists of all to the front of the
mouth-somite, and indeed is apt to be confounded in part with the
latter, as its upper surface is bent back and lies partly obscuring it.
Viewed from above, after the concealing first pair of elytra are
removed, it appears sharply defined and roughly heart-shaped, with
two pairs of black eyes set widely apart (Fig. 3). Long appendages
of sensory function, borne on separate peduncles, are given off from
the fore edge. Four are in pairs, while a median unpaired one, the
_ median antenna, is given off, rostrum-lke, from the central point.
On either side of this is a rather short, almost conical process, the
superior-lateral antenna; while attached immediately beneath each
is a stout, very extensile organ, the inferior-lateral antenna or palp.

In addition to these, the dorsal and ventral cirri of the peris-
tomium have to be considered as supplementary head appendages, as
they are specially elongated and are directed forwards at the side of
the true appendages, acting in unison in sensory duties. They
receive the distinctive name of tentacular cirri.

From the paired nature of the prostomial organs, it has been
suggested that, as happens among the Crustaceans and the Insects,
the head has resulted from the coalescence of several somites, which
in losing locomotive duties have been profoundly modified to subserve
sensory uses. But a very serious objection to this is, that all the
prostomium results from one particular part of the larva, known as
the prze-oral lobe, and which at no period of its history shows any
suggestion of segmentation.

Turning now to internal arrangement, we find that the mouth
leads into a well-marked pharynx, the anterior portion of whose walls
lie in puckered folds capable of being everted like the finger of a
glove, and thus allowing of the protrusion of the hinder portion, so as
to form a proboscis. This hinder portion has walls of great thickness
and muscularity, and the anterior end when protruded, is crowned
with a circlet of conical transparent papille, each containing a dark

102 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

pigment spot. Just within this ring are four horny beak-like teeth,
that bespeak plainly the essentially carnivorous nature of the Poly-
noins. Indeed one has but to keep a number of them together for
some time to find proof of their cannibalism, in the bitten and torn
parapodia of the weaker individuals, and undigested bristles can
frequently be traced in the matter contained within the intestine
of newly captured ones.

From the pharynx, the alimentary canal passes direct in a
straight course to the anus. As in the closely related Aphrodite, it
gives off in each somite to the rear of the muscular pharynx, a right
and a left glandular pouch or caecum, whose function we are yet uncer-
tain of. Curiously enough, the anus is not terminal, but, as in the
Copepoda, is found upon the dorsal surface of the penultimate segment.

A definite respiratory, or pseud-heemal system, was long denied
to the Aphroditidz, but Salenka and others have demonstrated in
Aphrodite and other species, a highly developed series of fine closed
tubes containing fluid apparently respiratory in use, but almost
invisible because of its all but entire lack of colour.

These vessels are in no way concerned with the diffusion of
digested nutriment. That duty is taken charge of by a corpusculated
fluid filling the general cavity of the body (Coelome), and which
circulates readily through the whole length of the body by reason
of gaps being present in the septa that break the coelome up into
numerous chambers.

Each of the septa here mentioned is a vertical partition wall
or rather transverse membranous mesentery, parting the coelome of
adjacent somites throughout the greater part of the body, but
suffermg modification in the anterior portion of the animal, where
the evertible pharynx requires special freedom of movement.

The nerves consist of a large cerebral mass above the mouth,
connected by a commisure passing on either side of the pharynx,
with a chain of ganglia in the ventral wall of the body. In reality
this chain is double, but is so far coalesced as to appear single.
Each somite possesses one of these double ganglia. From the upper
and anterior edge of the cerebral nerve mass, nerves are given off to
the median and to the superior lateral antenne, while the palps are
innervated from the ventral surface. Segmental organs, excretory in
function, are also present, but extremely minute.

REPRODUCTION. The sexes are separate, but no special ovaries
or testes are present ; the genital products being developed as cellular
masses from the internal surface of the body walls. The products
ripen and are set free in the coelome, whence they obtain egress,
either by rupture of the body-wall, or by way, perhaps, of the
segmental organs in some cases,

MICROSCOPICAL STUDIES. 103

The embryos have the characteristic Polychete form, being
trochophores, that is, they are rounded bodies with an encircling
band of cilia immediately in front of the mouth, the portion in
front of the band, forming the pree-oral region already referred to
as the precursor of the adult prostomium.

Adult form is soon assumed, but for some time after so doing
the young pursue a pelagic existence, swimming freely on the surface
of the sea, and frequently falling victims to the snare of the tow-net.
Like the adults these larve are brightly phosphorescent upon irri-
tation—the luminous areas being the elytra.

-The Polychztous Annelids, or Polycheetes, to which Polynoé
belongs, include nearly all the marine bristle-bearing worms. Very
few (only some half-dozen rarities) are inhabitants of fresh water ;
whereas, on the contrary, the Oligochetes (the few-bristled annelids),
extremely rare in the sea, have in fresh water and upon the land,
practically the entire monopoly.

Polynoé is very closely akin to the lovely iridescent Sea-mouse
(Aphrodite aculeata), so often dredged in sandy estuaries. Both
belong to the same family, Aphroditide, but to different tribes,
namely to the Polynoine and the Hermionine respectively. The
former comprises a great number of species, marked off from one
another chiefly by differences in the number and ornamentation of
the scales, and in the sculpturing of the sete.

I might have chosen a much simpler type whereby to illustrate
the anatomy of the Polycheetes, but on the principle of the axiom
that the greater includes the less, I chose Polynoé, as in it, com-
plexity of anatomy reaches its highest development and if we become
familar with its general features, we need not be afraid of being
puzzled to understand the modifications seen in other forms.

The present species, P. propynqua, is dominant in the Channel
Isles between tide-marks, but in the Irish Sea I found it extremely
rare, its place being taken by the stouter P. imbricata. Both these
are prowling robbers, without home or sojourning place, but many
species take up uninvited lodging with some of the larger tube-
forming worms, or with Echinoderms. Thus two species live with
the strange Chcetopterus in his great parchment tube, one with the
giant Hunice sangwinea, one with Terebella, and another in the
ambulacral groove of the starfish Astropecten, while a tiny one lies
sometimes among the tube-feet of Hchinus, and yet another, one of the
most beautiful, finds safe dwelling among the spines of the purple heart
urchin Spatangus. Such are termed commensals or messmates, but
the mutual relations subsisting between the host and the guest are
obscure and little understood. It may be that the annelid frequents
the host for protection only, sallying out in quest of food when

104, JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

hunger presses, but that there is something more seems argued by
the fact that each species is always found with its own particular
host. If it were a question of protection only, would not the tube
of one worm be as good as that of another ?

Another curious point about these worms is the great power
possessed of reparation of injuries. If in danger, it is the invariable
habit of P. propynqua, in common with many allied species, to break
up into two or three fragments in the hope of the head part being
able to escape under cover of the consequent confusion. If it be
able to do so, in a very short time a number of rudimentary somites
appear sprouting from the broken end, and these grow and increase
until finally the full and complete size be once again attained. I
have seen individuals in all stages of this regeneration, but have
never seen the hinder or tail fragment of a ruptured worm reproduce
a fresh head, as has been recorded by some writers. Such however
would, I believe, be likely to occur were the fracture close to the
head, but usually it occurs much nearer to the tail than to the head,
and in such cases I feel sure that the tail portion dies.

Stupy XIII.—THeE TappoLte LARVA oF ASCIDIANS.

The Tunicates or Ascidians, may be either fixed or free ; simple
or colonial. The central type of the free is seen in the Appen-
diculariz, transparent tadpole-like animals that sport in the surface
waters of our seas, in profusion, at certain seasons. In size these are
extremely minute, the British species averaging only 3-1n. to }-in.
in length, tail included, while the length of 14-in. which a foreign
species reaches, is altogether exceptional and monstrous. In this
type, the tail is supported and strengthened by a firm central rod,
the notochord, believed to be a similar structure to the first sup-
porting stiff axis of the embryos of vertebrates, and which in them
is subsequently usually obliterated by the encroaching growth of the
vertebral column. Another curious point is that two openings com-
municate between the pharynx and the exterior, and serve as gill
slits.

These tiny ocean wanderers are never colonial, always free and
simple. The fixed Tunicates, the Ascidians proper, are, on the
contrary, very frequently colonial, or as some writers term it, com-
posite or compound. In such latter, there is usually a certain amount
of federation, such for example in those where the anal apertures
of a circlet of individuals open into one common atrial or cloacal
chamber, to be expelled by a centrally place atrial opening.

MICROSCOPICAL STUDIES. 105

In size, the colonial individuals are usually very much smaller
than the simple, but in structure the two are essentially similar,
having the anterior portion of the alimentary canal distended into a
large chamber, with walls perforated by numerous gill slits, a nervous
system reduced to a single rounded mass (ganglion) between mouth
and cloacal aperture, a blood system of much simplicity and an
enveloping case of nearly structureless semi-cartilaginous or gela-
tinous tissue, the tunic or test.

July and August is the breeding season of many species, and if
one of these animals be then dissected, eggs and embryos in various
stages of development will be found.

Taking one of the most advanced, the following points can be
observed. The body is a tiny oval, slightly flattened from side to
side, while from the one end is given off a long broad tail, containing
centrally a clear rod of a cartilaginous substance. Both the body and
the tail are invested in a thick coat of gelatinous material, equivalent
to the test of the adult fixed animal. Turning the animal on to one
side (when the tail is found to be now on edge) one can, by staining,
make out clearly the thick investing test,in which lies the darker stained
kernel-like body. At five points the test is broken through; three
of these are where, at the anterior end, there pass an equal number of
tiny rod-shaped papille spreading into wide heads on their emer-
gence. These are glandular in function, secreting a tough glutinous
cement whereby the larva when tired of a free life, attaches itself
to a rock or weed. The other two points where the test is pierced,
are upon the dorsal side, and in the larva of Aplidiwm elegans are
situated far back. The anterior is the opening of the mouth (0),
and is separated by only a short interval from the posterior, which
is a depression indicating where the atrial aperture breaks
through. The mouth opens into a wide pharynx occupying a great
part of the larval body space. In the stage figured, the stomach
is just beginning to be apparent as a thick walled canal in a ventral
position towards the hinder part of the body, and connection is
just being made between the atrial cavity and the intestine. In
the advanced larva several openings pierce the pharynx and
allow water entering through the mouth to pass into the atrial
cavity without having to traverse the stomach and intestine. Such
openings are obviously the same as are so numerous and so apparent
in the adult. In Fig. 4, Pl. x, they show as two rows of disc-shaped
thin places in the pharyngeal walls.

The nervous system, of the most extreme simplicity in the adult,
has in the larva a complicated and highly developed arrangement.
As in the Vertebrata, it takes its origin as an open furrow stretching

106 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

longitudinally along the dorsal side of the body. The edges gradually
grow upwards and inwards to meet, and thus form a tube which now
constitutes the central nervous system of the animal.

The anterior end gradually swells into a large vesicle, while from
the hinder end of this, there runs a rapidly narrowing tube which is
prolonged into the tail as the caudal nerve. ‘The large anterior
vesicle contains two peculiar sense organs, an eye, and an otolith
perhaps of auditory value. These can readily be made out in
mounted specimens, as both are darkly pigmented and show
conspicuously, rendering easy the location of the cerebral vesicle
lying between the mouth and the atrial opening. Of the two, the
eye 1s much the more complex, for it possesses a cup-shaped retina
in which is placed a projecting and complex lens. It is placed at
the posterior upper corner of the vesicle and projects downwards
towards the centre of the cavity. The otolith on the other hand,
rises upon a stalk from the floor of the vesicle more to the front end.
It is noteworthy that both are within the vesicle.

The after history of the animal is quickly told. The larva
affixes itself by the glutinous secretion of one or all of its three
papillee to some object ; the tail with its contained notochord, as well
as the three anchoring papilla become absorbed; the test becomes
enormously thickened and strengthened, and the perforations of the
pharynx become multiplied greatly, and most significant of all, eye
and otolith vanish utterly, the well developed nervous system being
reduced to a fairly large ganglionic mass occupying the position of the
cerebral vesicle of the larva, 2.c. midway between the mouth and the
atrial opening. Radiating nerves to the various organs are thence
given off. The course of these changes brings about a certain alter-
ation of placing of the two external apertures, as may be seen in the
diagrams ; thus the mouth in the fixed larva of Aplidiwm is at first
not terminal, but gradually becomes so, thus necessitating a corres-
ponding travel of the atrial opening. There is, however, no real
travel of these parts, simply a more rapid growth than of the opposite
side, of that part of the body wall and test lying below the mouth,
ae. between it and the point of attachment to the rock. This
naturally pushes the mouth upwards, and finally places it in a
terminal position, at the point of the body furthest removed from
the point of fixation. Budding produces a cake-shaped colonial mass
of a general pink colour, flecked with white points indicating the
position of the mouths of the various individuals or ascidiozooids.

With the assumption of adult form by Simple Ascidians, the
genital glands develop, but among the Compound, a frequently long-
continued course of budding, takes place prior thereto. All species
are hermaphrodite, but as a rule the male and female organs do

MICROSCOPICAL STUDIES. 107

not ripen at the same time. The young produced are the tadpole
larves we have above described.

Only within the last 28 years have the Tunicates bulked with
large importance in scientific ken. Until 1866, when the Russian
naturalist Kowalewsky published his famous researches and specu-
lations upon the embryology of the group, they occupied a position
of comparative isolation, with ill-understood affinities, and were
generally treated as aberrant forms of little importance. Some were
for placing them among the Mollusca, largely upon the count of their
acephalous (headless) condition; others from the peculiar looped
form of the alimentary canal would have that they were peculiarly
developed relatives of the Polyzoa. The lowly development of the
venous system favoured alike either of these views.

But Kowalewsky’s researches altered all that, and gave the
Tunicates a status of great importance. He pointed out how the
adult Appendiculariz and the tadpole larvee of the fixed Ascidians
bear many close resemblances to the lower vertebrates, especially to
the Lancelet (Amphioxus), such for instance as the presence in both
of a stiff central axis, the notochord, and the occurrence of a central
nervous system expanding into a large cerebral vesicle at the anterior
end. J inally he pointed out the perfect concordance of the perfor-
ations of the Ascidian pharynx, both larval and adult, with the gill
clefts of the Lancelet specially, and of fishes generally.

Huxley and Haeckel warmly espoused this view so carefully and
logically put forward, and now it reigns as the orthodox opinion.
Prof. W. K. Brooks, who has within the last few weeks published
an extremely valuable monograph upon the Salpe, a group of much
modified and altered pelagic Tunicates,* after a fresh and independent
investigation from new stand-points and with many new facts to put
into witness, fully endorses the same view, and states his belief
that a simple pelagic form, of which Appendicularia is the nearest
living representative, 1s the common ancestor of all the Chordata, 7.e.
alike of the Tunicata as of the Lancelet and all the Vertebrata.

Of course such theory can never be proved with mathematical
certainty. It is at best a plausible probability, the most probable
explanation of the mode of descent of the higher animals we at
present know of. But there are, and have been, capable investigators
who cannot bring themselves to accept it. Thus Prof. Giard, who as
the first occupant of the chair of Darwinism at the Sorbonne, cannot
be considered in any way a scientific reactionary, in 1872, after
elaborate investigation of the Compound Ascidians, refused to endorse
this opinion. He then could see nought but a convergence or coinci-

* “ The Genus Salpa,”’ Baltimore, 1893.

108 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

dence in general form between Ascidian larvee and lowly vertebrates,
due he believed to a similar mode of life, 2.¢. free-swimming. He thus
considered the adult as the true or fundamental form of the Tunicate
group, and the larve not as a reminiscence of ancestral freedom, but
as a larval form that for its special and temporary needs, assumed
through like requirements of mechanical stresses, due to the adoption
of a similar mode of progression, swimming, a form akin to that of
a lowly vertebrate.

If we want to go astray in reasoning, it is often easy enough
with the exercise of a little ingenuity or else of some obtuseness to
sink deep in the mire of false deduction. Anyone not thoroughly
master of an intricate subject may easily mistake cause for effect,
and conversely, and I remember once when considering this Ascidian
problem, thinking what a grand opportunity exists in the life-history
of Appendicularians for such an one to go astray. Among these tiny
tailed swimmers, the habit exists, at certain times, of forming a
gelatinous envelope in which the animal lies enveloped for a short
time—the “ Haus” this has been termed; and it is obviously
homologous ,to the test of the fixed Ascidians. Now a very
probable line of descent of the latter is from Appendicularians
that have taken this “haus” stage as a permanent adult condition
and so have deserted the free-swimming life—evidence being that
the fixed Ascidians recapitulate very closely, in their larval condition,
the general form, together with many of the essentially characteristic
internal features of adult Appendicularians. But the student not
thoroughly on his guard against the pitfalls of evolutionary reasoning,
might easily deduce that the Appendicularians are arrested larvee
of fixed Ascidians; that is, that certain larvee instead of performing
the full life-history of their race, retained the tailed form all their
adult life, and that the occasional formation of the “haus” is the
atavistic recollection of the fixed Ascidian condition ! !

In reality such conclusion is easily refuted, and there is really
no reasonable doubt that the tadpole larvee show the ancestral form
fairly clearly. 'To mention one argument only, why should they have
a nervous system infinitely superior to that of the adult, formed too
on a plan entirely different from any to be found among inver-
tebrates, but characteristic of vertebrates ?

Correction. —On page 18, line 6, read “ovary” instead of “ oyum.”

The Hownal of Marine Soologn
and Jiliqnoscopy :

A PLAINLY WORDED BIOLOGICAL QUARTERLY

You. Il. No. 5. MARCH, 1895.

THE LIFE-HISTORY OF THE ROCK BARNACLE,
(BALANUS).
13) 5 NISL IB O) pal (CE OO) NLS 1 yan She
(Part []).

HE question of the meaning of the various larval forms known, has,
for many years, engaged the attention of naturalists, and, thanks
to the writings of Darwin, Haeckel, Fritz Miiller, Hatschek, Lang,
Lankester, Balfour, Sedgwick, and others, we are gradually getting
some idea of the true meaning of the facts of development. In the
following pages, I do not pretend to set forth anything essentially
new, but merely to illustrate some of the pomts which arise when
one considers the development of animals belonging to such a group
as the Cirripedia.

In comparing the anatomy of two animal forms, zoologists
very commonly restrict themselves to a consideration of the adult
forms alone. It is found, however, that in some cases the adult of a
certain form resembles the larva of another form more than the final
or adult stage of the latter, or more frequently that two forms widely
different in adult structure have very similar larve. The structure
and development of the curious parasitic Cirripede Sacculana, bears
out these statements. The adult differs greatly from such a form as
Balanus, though the Cypris-stages of the two show great agreement.
In order to ascertain the true points of agreement of two forms,
it is necessary, then, to compare not only the adult but also the
young forms: hence the importance of embryology from a morpho-
logical point of view.

We may represent an animal form by the symbols A BC D,
D being the adult, and A, B, and C successive stages in its deve-
lopment : now in the production of a higher form from a lower, we

2 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

may suppose that all the stages of the lower form are passed through
and a further condition reached. Thus we may get a new form E
which shows in its development the stages A, B,C, D and E. Were
the course of evolution as simple as this we can readily sce that “ the
development of the individual would be a recapitulation of that of
the race.” Species, however, arise by the modification of old ones in
more than one way. We may distinguish :—

(1) Species which have advanced in organization.

(2) Species which have retrograded.

(3) Species which are simple transformations of old ones, not higher
or lower in organization, but possessing new characters.

In the two first-mentioned groups we may suppose a species
A BCD E to have arisen from an older one A BCD, E being
either a more complex, or a more simple form than D: in these cases
the development (in the later stages at any rate) indicates the source
of the race. In the third case, however, instead of the series A BC D
we should get a new series A BC E, the stage D being omitted,
owing to the selection of variations which appear as entirely new
characters, and not merely as higher or lower conditions of the cha-
racters seen in the stage D. In this case, it is clear the development ~
is only an incomplete recapitulation of the phylogeny.

In spite of this, were the adult the only variable stage, the task
of tracing the ancestral history of a form would be much easier than
it actually is. As a matter of fact, however, variations affect not
merely the adult, but also the earlier stages.

If we compare the larve of two very similar animals, we shall
not unfrequently find considerable differences; these can only be
explained by supposing the larve to vary. It would, indeed, seem
true that any variation in the adult, must, to a certain extent, be
represented by a corresponding difference in all earlier stages, for
each of the latter must possess all the potentialities of the adult; but
independently of this the variations are considerable. One can readily
convince oneself of this by comparing the very different kinds of
larvee seen in any one of a number of animal groups, such as the
Insecta, Crustacea, Mollusca, &. We may, then, represent a species
derived from a form A BCD, not by the symbols ABC DE, but
as A; B,; C; D, E (supposing for the sake of simplicity that all the
stages become thus modified): we might, however, get such forms as
A, B, CD, Hy, A; B, C; DE, the stages C or D being supposed to
remain unaltered. Further modification would lead to the successive
forms A, Bz C, D, E, F, A; B3 C3 D; Ez Fj G and so on. The later
phylogenetic history of the last-mentioned form is DE FG: but Da,

LIFE-HISTORY OF THE ROCK BARNACLE. 3

for example, may be quite different from D, and E, from E. When
modification in the development has proceeded so far, we might
represent the new form by such a symbol as A BC P Q R G, the three
earlier stages being supposed in this case to have remained unaltered,
whilst the stages D, E, and F have become so much modified that
new symbols P, Q, and R are required to indicate them; where the
adults have changed little we might get such formule as A Q C D,
PQRD, &c. In such cases the development will only to a very
limited extent express the history of the race. This “ falsification ”
of the record was recognised many years ago, and Haeckel showed
that in considering the development of any animal we must dis-
tinguish characters which were palingenetic, or ancestral, and
characters which were cenogenetic, or acquired.

_A further set of disturbances may be, and very commonly actually
_ appear to be, set up in the development by the early or precocious
appearance in the young form of characters belonging to the adult.
Thus we may get sequences such as the following :—A BC D,
A, By, d Dy, and Ay dy dz Ds, the larval forms B and C being replaced
by d; and ds, which already show many characters originally confined
to the later stage D.

The problem as to the value of a given larval form is thus a very
complicated one, and we have to face the question as to how we can
eliminate the cenogenetic or acquired larval characters. In the case
of relatively rapidly acquired characters this can sometimes be done
by comparing the development with that of remaining members of
the group: if the embryos and larve of a form show characters which
differ widely from those seen in the young forms of the rest of the
group, we may reasonably believe that the development has been
modified, especially if we can point to special features in the environ-
ment which would be likely to bring about such changes, or if we have
reason to believe from the structure of the adult that we are not
dealing with one of the most primitive forms of the group. Much
may be learnt of the primitive mode of development by seemg which
characters are common to the embryos and larve of the various mem-
bers of the group, and valuable clues may be obtained by studying
the development of the form to which adult anatomical structure
points as the most primitive ; for supposing all stages to vary equally
in a given length of time, we may reasonably conclude that the
adults which have been least modified will have the least modified
larvee.

Let us suppose that we have succeeded in eliminating many of
the cenogenetic characters from the development, say, of the Barnacle,
and have an idea of the series of young forms passed through by the

4, JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

immediate ancestor of the Cirripedia, we must still bear in mind that
the development is not necessarily a recapitulation of the phylogeny.
This point was overlooked by Fritz Miiller in his classical work “ For
Darwin.” ‘This philosopher, seeing that the typical development of
the Crustacea was by means of a Nauplius, concluded that the Nau-
plius represented an ancestral form of the group. To make this clear
we may suppose that we have two Cirripedes, A; B, C; Dy; and
A» Bz Cz D2: the close resemblance of the stage A; to A», of B, to
B, &e., may at first sight seem only explainable on the view that
A, B, and C represent ancestors. Thus if B; and Bz represent Naupli
of two species D, and Dz of the group, the resemblance between
B, and B, is so striking (extending even to the minute character of
the numerous hairs and other processes shown on the appendages)
that we can only conclude that similar characters were possessed by
the ancestral form ; one might then jump to the conclusion that the
Nauplius must represent an ancestor of the group: such a con-
clusion is now known to be unjustified, for the characters, though
necessarily present in the ancestor at some stage in the development,
were by no means certainly found in the adult condition; im fact
so far as we can tel! from the development of the two types, it is
clear that they did not belong to the adult of the immediate ancestor,
for the two adults present an equally great resemblance to one
another in a totally different way, comparatively few of the striking
characters of the Nauplius bemg found at this stage: the resem-
blances in the case of the adults are of such a character that we can
only conclude that the similar characters in their case also, are due to
inheritance from a common ancestor: the same may be said of each
of the other stages, and it clearly follows that all we can conclude
from the similar development of the two forms A; B; C; D, and
Az Bz Cz Dz is that the common ancestor had a stage corresponding
to each of foregoing stages, and that the development may be repre-
sented by the formula ABCD. It does not, then, follow from this
alone that B, for instance, is an ancestor of D; or D2; at the same
time nothing disproves this view: the question must be decided upon
other evidence.

If the modification of forms leading to D has been a progressive
one, C will represent an ancestral form, and its life-history will be
A BC: the discovery of such a form would appear to furnish the
only satisfactory evidence as to the ancestral history of D. Judged
by this standard, the trochosphere or larva of many annelids, mol-
luses, &e., has great value, for we find a number of adult animals
which are either practically in the trochosphere condition (Rotifera,
Polyzoa, &e.) or are but little removed from it. The same may be
said of the embryo of Birds and Mammals with its gill-slits, for we

LIFE-HISTORY OF THE ROCK BARNACLE. 5

find more primitive forms (Fishes, &c.) which in their adult condition
have functional gills, and share many other features with the higher
vertebrate embryo. On the other hand, we find no adult forms at all
like a Nauplius; the comparison, too, of the anatomy of adult Crus-
tacea lends no support to the view that the ancestor of the whole
group had the simple structure of a Nauplius, the common characters
of the adult members of the group giving us a picture differing
considerably from that of such a form. Many characters of this larva
are, however, so strikingly like those of adult members of the group
(e.g. presence of carapace, labrum, jointed appendages of special
character, Nauplius-eye, caudal furca, dorsal anus, &.) as to suggest
that it is merely a form which has acquired early the characters
proper to the mature form.

The study of embryology is, indeed, replete with questions of this
kind. We may at first be inclined to chafe at the difficulties we
meet, and to wish that the life-history presented us with a perfect
picture of the history of the race, but it must be remembered that
the reconstruction of the genealogical tree is not the only task of
biology. The study of the special adaptations of larvee to their
surroundings is one of great importance: the adaptive relations of
the adults have, indeed, formed a branch of natural history, but
comparatively little has been done in viewing the young forms from
this teleological point of view. We ought to have as accurate a
knowledge of the use and adaptation of the parts of larvee, as we aim
at getting in the case of the adults. Interesting results have, indeed,
been obtained in this direction, and amongst these I may specially
mention Prof. Miall’s late investigations on aquatic Insect larvee, but
a great field is still open to anyone who will undertake it.

LSPA ATION On PEATEs la avion., sh,
Tife-History of Balanuws (Part I).

Fig. 21. Tergum of young Balanus balanoides considerably mag-
nified to show the punctures on the shell.

Fig. 22. Last Nauplius-stage (VI) of a species of Balanus obtained,
together with the Cypris-stages of B. balanoides, from
Jersey. In addition to the three pairs of Nauplius-
appendages and first pair of maxille, the remaining
appendages can be seen beneath the cuticle. The com-
pound eyes can be seen through the antennules on each
side of the Nauplius-eye: through the basal part of the
labrum can be seen the cesophagus suspended by simple
unstriated muscular fibres. The position of the gnatho-

6 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

base, or movable jaw-piece of the antenne just behind
the mouth can be clearly seen. Inside the antennules
can be seen the developing prehensile antennules of the
Cypris-stage, the newly-formuing shell of which (Cypr. sh.) —
can be seen retracted from the carapace. The first pair
of maxillae can be likewise seen retracted some distance
forward from the external processes in which they were
formed. |
Developing compound eye of a somewhat younger Nauplius
of the same species, showing the polygonal retinulae,
with their red pigment (which at the stage shown in
Fig. 22, has become black). 3
Fig. 24. Side view of the Cypris-stage of the same species just after
the moult, showing certain transitional features—
a. prehensile antennule; @”. relic of antenna; ep. edge,
edge of carapace (not yet closed); 7. f. frontal filament ;
jr. l. ap. aperture of fronto-lateral gland, marking former
position of horn ; bv. labrum ; mn. mandibie ; mal. first
maxilla ; ma. second maxilla; 0. gl. oil globules ; rnf. gl.
reniform gland; th. thorax; th. ret. retractor muscle
of thorax-abdomen.
Fig. 25. Ventral view of similar stage. Letters as in Fig. 24, also
th. app*. first pair of thoracic appendages.
Fig. 26. Cypris-stage of an undetermined Cirripede, possibly that of
Chthamalus stellatus, obtained from Plymouth.
Lettering :—add. sc. adductor muscle; a. prehensile anten-
nule; buc. m. buccal mass; ca. app. candal appendage; fr. L. ap.
aperture of fronto-lateral gland; ant. intestine ; Npl. eye, Nauplius-
eye; 0. gl. oil globules (large and colourless) ; 0. gl’. masses of minute
ereenish yellow oil globules; ov. s. oval sac; rnf. gl. reniform gland ;
st. stomach; th. thorax; th. gg. ch. thoracic ganglionic chain.
Fig. 27. Side view of Cypris-stage of Balanus balanoides. Letters
as in Fig. 26.
Fig. 28. Ventral view of same: the thorax lay obliquely in this
specimen, an unusual condition. Letters as in Figs.
26 and 24.
Fig. 29. Cypris-stage of same species after fixation. The antennae,
by means of which fixation occurred, have been torn
away, having remained attached to the rock.

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SR SR RGR RR SR

Journ. of Mar. Zool. & Microscopy, WOite Dey IP I,

Sp ae

eeuese mmf gi ot

THEO. T. GROOM, DEL. ad Nat J. HORNELL, Sc,

THE DEVELOPMENT OF BALANUS.

ON THE IRREGULAR GROWTH OF THE SHELL OF
THE COMMON LIMPET IN CONFINEMENT,

BY JOHN E. ROBSON, F.ELS.

Many years ago, when “The Aquarium” of the late Mr. Gosse
gave such an impetus to the study of marine life, I became smitten
with the prevailing fashion and determined to commence an Aqua-
rium. Mr. Gosse did not say much about the difficulties in the way
of success, and, in my ignorance, I imagined that marime animals
would live in a small receptacle, just as they did in the little rock
pools on the shore, not even taking in#6 consideration the fact that
these were over-washed twice a day by the tide. I was just ignorant
enough to be unaware of my ignorance, and commenced with suffi-
cient enthusiasm for a very much greater undertaking, had it only
been tempered with a little knowledge or experience. I had a small
gold-fish globe, holding perhaps a gallon of water, and this I deemed
all sufficient for my purpose. I searched among the rock pools, and
brought away one specimen of every different kind of small animal I
could find, expecting them all to live and thrive in this little vessel. At
least three species of fish, a small “ dog-crab,” a hermit crab, a shrimp,
a periwinkle, a top shell, a limpet, the latter bemg on a piece of
stone, partly covered with barnacles and small mussels. Some sand
and fine gravel was put at the bottom, a few pieces of stone with sea-
weeds growing on them were piled up in the centre, and I expected
I had done all that was necessary. Within twenty-four hours every-
thing was dead, except the limpet. I could not understand it, but
was quite ready to try again on the same Imes. The dead animals
were taken out, the barnacles and mussels scraped off the stone on
which the limpet resided, more fish and other things were procured,
only to share the fate of their predecessors. I am not sure that I
even changed the water. Again it was re-stocked, but I removed
the limpet from the stone, which now had a bad smell on the under-
side. The sides of the glass were beginning to be coated with green
conferve, and on this I placed the limpet. IJ had some difficulty in
getting it to adhere to the double concave glass, which was very
different from the level but rough surface of the stone on which it
had resided. At last it fixed itself, and browsed contentedly away,
mowing down the conferve in regular curves as it slowly moved
along. I do not wish to dwell on my continued failures, nor
to record the slow process by which I eventually gained some
little idea of the conditions necessary for success. While every-
thing else perished, the limpet still survived, and at last I noticed it

8 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY,

was adding to its shell. Ere long two things were apparent. First,
the new shell was paler in colour than the old, and second, that the
recently added portion was at a different angle to the original, so as
to cover a larger surface, thus _-/\—_

As the animal moved about, the shell was shghtly raised from
the surface, and owing to the double curve of the glass, it was
evident it had to be raised more than was convenient or desirable.
When the shell was widened it did not need to be raised so much.

This limpet lived a considerable time in this small vessel, and
having now gained a little experience I ventured upon a further
experiment. I procured a large propagating glass, had a ‘stand made
to fit the curved and knobbed end, and then had an Aquarium of
considerable dimensions, holding several gallons of water. The glass
formed only a single curve, the vessel being circular im shape, but
the sides being straight. As soon as the sides had a coating of green
I transferred the limpet to it. Here it lived for several months,
during which time it again added considerably to its shell, and again
the addition was at a different angle. WIAs

ea

=,

Not so obtuse as the previous enlargement, nor yet so acute as
the original shell. The change of angle was very distinct in each
instance.

This I considered to be further evidence in support of the
previous suggestion, that the shell was made wider so that the
organs should not be unduly strained to raise it from the convex
surface. The present glass, though not by any means so level as the
rock on which it resided in a state of nature, had yet a curve of much
greater radius than that of the former vessel, and the new curve was
single, not double as before. Thus the changed angle enabled it to
assume the required position with less inconvenience.

Was this the result of some volition on the part of the animal,
or was it caused by the shell-secreting organs being forced from their
normal position? In any case the change of angle appeared to be
to the advantage of the animal, and I have no doubt were limpets
reared from the commencement of their lives on curved surfaces like
those of either of my vessels, the angle would be much greater, so as
te produce a flatter shell than when they live on a level or nearly
level rock. :

GRD San} Ge > G22 GR GRA
MS SRE IR RSE RS RK

A CONTRIBUTION TO THE ZONING OF THE SHORE.

BY JAMES HORNELL.

The zoning of the littoral of the south coast of Jersey, has of
late attracted much of my attention. Here, owing to several physical
causes, the conditions of life are most peculiar. The tide has a rise of
fully 40 feet at certain times; the littoral is extremely broad and
diversified—two miles of rugged reefs, rock-pools, gullies, and zostera
banks, often intervening between high and low water marks; life
competition is wonderfully keen, and the variety of this life is
immense ; finaily, the mildness of the climate and the balmy warmth
of the Gulf Stream waters that impinge on the coast, have stim-
ulating effects upon the littoral life that can with difficulty be
adequately appreciated by those not intimately acquainted with such
influences.

Undoubtedly the most conspicuous instance of zoning is afforded
by the olive-green (brown) seaweeds. On this coast they furnish well
marked regions, and in descending order are :—

1. Zone of Fucus canaliculatus, some four to five feet broad—the
upper edge net covered at high water of neap tides.
- Zone of Fucus vesiculosus and F, platycarpus, extending from
the lower edge of the preceding to half-tide mark.
3. Zone of F. nodosus, from half-tide down to five feet above
low water.

bo

4. Zoue of F. serratus—the five feet above low-water mark, where
F. serratus grows without intermingling of other species.
It is also found as far up as half-tide, mingling with
F. nodesus, whose zone it thus overlaps.

5. Zone of Laminaria, extending downwards from low water, with an
average breadth of 25 to 30 feet.

Another distinct set of zones on this coast is made thus :—

1. Balanus zone. ‘The barren region covered with innumerable
B. balanoides, lying between high water mark of spring and of
neap tide.

2. Limpet zone. Somewhat overlapping the lower edge of the
Balanus region, and ranging downwards to low water; the
limpets grow very scarce as the Laminarian zone is approached.

- Haliotis zone. Almost equivalent with “Laminarian zone.”
Characterized by the presence of the magnificent gastropod
Haliotis tuberculata.

Sars and Loven and others intercalate a fourth zone, that of the
pink seaweed Corallina officinalis, between 2 and 3, giving in descend-
ing order: 1, Balanus; 2, Limpets ; 3, Corallina; 4, Laminaria.

(oe)

Be

10 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY,

Such cannot, in Jersey, be made out, for the Corallina region ranges
considerably further than half way up the Limpet zone, and is indeed
inextricably commingled with it, while Limpets are to be found
almost at low water limit, though in small number. |

As useful guides in fixing the vertical distribution of other
animals, both these zonings are faulty; the first because of the
frequent absence of fucoid growth in particular localities, and the
second because we require a greater splitting up of the space to
be mapped.

For this purpose it is indispensable to choose a group comprising
numerous fairly common species, preferably sedentary.

The Sponges, I find, are too aggregated in the lower half of the
littoral, to be serviceable. Thus the highest-living species, Hali-
chondria panicea, is not met with at all above half-tide mark. It
however forms a very well marked zone, extending in solid phalanx
to within 5 to 4 feet from extreme low water, the intervening space
being what I would term the Pachychalina zone, characterized by
the presence of Pachychalina montagui, Isodictya ingalli, and a multi-
tude of ascidians—Ciona, Aplidium clegans, Morchellium, and the
Botryltids.

Below this, and corresponding with the Laminarian zone, comes
a region for which, in the zoning of the Sponges, I would propose the
term Tetractinellid Zone, signalised by the occurrence there of the
massive sponges Pachymatisma, Stelletta collingsi and Dercitus niger.
It may be noted, in passing, that one common Tetractinellid sponge,
viz., Tethya lyncurium, is sometimes numerous in the Pachychalina
ZONE.

The Ascidians are still more aggregated at low horizons than
the Sponges, while the Hydrozoa and the Polyzoa are often so
fastidious and erratic in their choice of habitat, that, to be uscd as
general indices, they are ill suited. I do not, however, wish it to be
understood that they are not to be found occupying well-defined zones.
Far from this being the case, their dominions have very rigid bounds,
capable of exact demarcation. I only mean that, for no apparent
reason, they may be absent from their particular zone in one part of
the shore, while common at the same height in another; a tantalising
inconstance, if we desire to use them as shore-marks.

The group, which, after this process of elimination, I found to be
the most generally useful in the demarcation of the shore, was that of
the Anemones. Here is no massing of species within narrow limits ;
the range is well nigh up to high water mark, and progresses by well
marked and fairly regular steps to deep water.

xy A CONTRIBUTION TO THE ZONING OF THE SHORE. 11

Highest is the zone of Actinia cquina, L. (A. mesembryanthemunr),
lurkimg in tiny pools and cool crevices quite up to high water of neap
tides; very tolerant of, and indeed happy in, periodical exposure to
the air. The vertical height of this region is probably about 12 feet,
merging towards the lower margin into a narrower zone characterized
by the presence, in crannies, of the lovely Gem Anemone, Bunodes
gemmaceus. This zone is not always well marked, and at times, seems
almost co-terminous with that of Actinia; where best shown, it
forms a hand beginning some 8 feet from high water of neap
tides, and extending to some 4 to 5 feet further than the lower
margin of the Actinia zone, 2.¢., to some 16 to 17 feet from neap tide
high water. ;

This region, at its lower boundary, passes rather abruptly into
that of the extremely common and hardy Anemonia sulcata (Penn.)—
the Anthea cereus of Gosse. Of the various species of Anemone,
this is the most abundant here ; common equally in rock-pool, among
the fronds of zostera, and scattered over the stony surface of many of
the bays. Not less than 10 feet vertically is taken up by this species,
and so brings us to within 5 feet of the lowest margin of spring tides
—an interval filled in by Zeala felina (T. crassicornis), whose zone
extends well down through the Laminarian region.

In the deeper parts of the Lamimarian zone, the commensal
anemone Adamsia rondeletii comes, while from the deeper water of
the Coralline zone (20 to 30 fathoms), we obtain the other British
species of the same genus, viz. A. palliata. Here too a large and
pale-coloured variety of Zealza lives.

To tabulate these regions, we have, taken in descending order,
the following :—

1. Actinia equina zone; Vertical range :—from high water to 12-ft. down.

2. Bunodes gemmaceus zone; do. :—8-{t., beginning at 8-ft. down.

3. Anemonia sulcata zone; do. Os, Comatose

4. Tealia felina zone ; do. :—the last 5-ft. of the littoral, beginning

at 26-ft. down (also the higher part of the Laminarian zone).

5. Adamsia rondeletii zone; the lower part of the Laminarian and the upper
margin of the Coralline zone; vertical range from 6 to 20 fathoms,

6. Adamsia palliata zone; the Coralline zone, from 18 to 30 fathoms.
All data from high water of neap tides.

0 2 sla Ge GR 1 GR
SIR IR IRS IN EBS

MICROSCOPICAL STUDIES IN MARINE ZOOLOGY.

BY JAMES HORNELL.

Stupy XIV.—SPH#ROZOUM PUNCTATUM, A COLONIAL
RADIOLARIAN.

No group of animals possesses such intense interest to the
Biologist as does that of the Protozoa. Located on the very outskirts
of life, one searches among their lower forms and studies their every
phase and attribute, in the hope of obtaining the faintest clue as to
the origin of life itself. Their higher developments we scrutinize
equally closely, for evidence as to the particular evolution of the
sponges, simplest among the higher animals—those Metazoa whose
bodies are made up of aggregations of cells, not one cf which is, of
itself, capable of prolonged separate existence, but requires the co-
operative assistance of other units, other cells, to carry on “ life.”

The Protozoa are, we know, typically unicellular, but many of
the most interesting forms seem very closely to counterfeit the me-
tazoan plan; though ever with this distinction,— separate one of their
cells, and straightway it can sustain long life and multiply its species
as though nothing radical had occurred. With these latter, our
attention now lies.

Most of us have seen, and admired with enthusiasm, that lovely
emerald-jewelled rotating globe of colonial life, the tiny Volvox of
our ponds. And though we cannot nowadays accept the firm belief
entertained by mariers of ancient times, that the sea contains coun-
terparts of everything moving on the land and in fresh water, yet as
regards Volvor, we may claim in Spherozoum and its alles, at least
forms having many outward resemblances. ,

Spherozoun is a colonial Radiolarian in which the skeleton con-
sists of loose spicules surrounding each individual of the colony, but—
before going into details of anatomy, it will be well for us to cast a
survey over the group wherein it 1s included. In the first place,
Radiolaria belong to that group of the Protozoa known as the Rhi-
zopoda, animals where locomotion and the capture of food is effected
by extensions (pseudopodia—“ false-feet ”) of the outer layer of the
body, ectosarc. The well-known Am@wba—long ago known as the
proteus animalcule on account of its constant change of shape, due to
the thrusting out of these pseudopodia first from one spot and then
from another-—1s one of the most primitive members. It is little else
than an animated microscopic speck of granular jelly-like protoplasm,
endosare, surrounded by a slightly denser and clearer layer, the
ectosarc; having a peculiarly- endowed dense speck, termed the
nucleus, embedded in the endesare, and wherein lies the poten-
tiality for future multiplication.

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Fics. A To E, AND 1, 2,3 & 4.

SPHAEROZOUM AND LARVAL ANTEDON,

Fig.

Fig. B.
Fig.

Fig.

Fig.
Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.
Fig.

EXPLANATION OF PLATE II, Vou. II.
Figs. A to F, Spherozoum punctatum.

Natural appearance of a colony, showing the numerous
individuals surrounded by the clear layer of the calymna.
x 6.

Diagrammatic section through the same, showing it to
consist of a hollow sphere ; cl. calymna ; ¢. sp. central space.

View of an isolated individual surrounded by a loose network
of spicules.

The same, with spicules removed.

o. gl. great oil-globule of capsule; nw. one of the several
nuclei; cp. capsular membrane; sm. sarcomatrix; alg.
symbiotic algee.

Three of the six-rayed spicules.

Scale of magnification of Figs. C, D, E, 3 & 4 (all original).

Figs. 1 to 9, Crinoids.

Free-swimming larva of Antedon (Rosy Feather Star), with
the calcareous plates of the stalked larva formed within.
c. z. one of the four ciliary zones. (After Thompson).

Young attached larva of same; t. pl. terminal or attachment
plate ; x. articulation of the joints of the stalk ; bs. a basal
plate of the calyx; or. an oral plate; rv. a radial plate just
beginning to form; ¢. circle of tentacles round mouth.
(Original).

An oral plate magnified to scale of fig. F. (Original).

Halves of adjoming joints of stalk, to show their cribriform
nature and mode of articulation at . Same magnification.
(Original).

A later stage than fig. 2, and just prior to commencement of
adult life. The dorsal cirri (cir.) and 5 pairs of arms
have just appeared. (After Thompson).

Pentacrinus caput-meduse (after J. Miiller),a form stalked
throughout life. The stalk has whorls of cirri (wh. cir.)
at intervals.

Rhizocrinus lofotensis, a young individual (after Sars).
This species remains stalked all through life, but instead
of a basal plate of attachment, is anchored by ramifying
root-like processes which twine round stones and other
objects.

Magnified view of the “ head” of an older stage of same.

Enerinus liluiformis, one of the most numerous of fossil
erinoids,

(The original figures copyrighted, March, 1895).

EXPLANATION OF PuatEe III, Vou. II.
Creseis acicula.

Fig. 1. Creseis acicula. Several of the internal organs are drawn
in optical section. a.anus; al. gl. receptaculum seminis ;
ce. f. ciliated furrow for conveying spermatozoa from the
sexual orifice to the penis; cv. sh. ciliated shield, respira-
tory in function ; jf. ”. main branch of fin-nerve; g. sub-
cesophageal portion of central nerve mass, showing the
great fin-nerves being given off from the anterior corners,
and the otoconia lying beneath; h. d. duct of receptaculum
seminis; h. gl. ovo-testis, or hermaphrodite gland ;
a. intestine; Ul. liver; m. l. middle and rudimentary lobe
of foot; m. n. mantle nerve ; np. nephridium ; 0. mouth;
oe. oesophagus ; ot. one of the two otocysts, containing,
not a single spherical body or otolith, but numerous small
calcareous bodies, whose mass is termed an otoconia,
(the function of these bodies is supposed to be auditory) ;
. 0. penial aperture situated at the base of the rudimen-
tary right tentacle; p. g. penial gland, or rather, the
indrawn penis; 7. m. retractor muscle; sh. shell; st.
stomach; sw. l. swimming lobe or fin; wt. di. uterine
dilatation ; ve. ventricle of heart.

Fig. 2. View of an nui Cresers (Fig. 1. had to be drawn in two
portions, as the length was too great for the size of the
plate).

Fig. C shows the homologies of a Gupiell Pteropod larva, (Cymbulia),
with the larvee of typical Gastropods, A and B; A being
a younger and B an older stage. (After Cenenben et
v. velum ; c. shell; f. foot ; op. operculum; ¢. tentacles.

Fig. D. Diagram of a simple bilaterally symmetric or Isopleurous
Gastropod (Chiton).

Fig. E. Diagram of an asymmetric or Anisopleurous Gastropod.

Fig. F. Diagram of a naked Pteropod.

BioasG: “f “ thecate or shell-bearing Pteropod.

Bigs El i “ Cephalopod.

(All after Lankester, G bemg modified).

D, V, A, and P point respectively to the dorsal, ventral, anterior,
and posterior aspects of the body.

The extent of the foot in each case is denoted by the dotted
shading.

o. mouth; a. anus; ff. fore-foot; m. f. mid-foot ; h. 7 hind-foot ;
ep. epilobium ; ¢. e. cephalic eyes; s. p.sub-pallial space ; m. s. mantle
skirt. or flap ; vs. visceral hump or dome.

(The original figures copyrighted, March, 1895).

Journ. of Mar. Zool. & Microscopy, Wows 2 alee. lil

Ave

JAS. HCRNELL, DEL. AD Nat.

Figs. 1 & 2,

PTEROPOD ANATOMY,

MICROSCOPICAL STUDIES, 13

A higher division of the same Rhizopoda are the Foraminifera,
animals of the amceba-type endowed with the faculty of building up
a skeleton, usually of lime (calcium carbonate), from whose surface
and from apertures in which, are given off numerous long whip-like
threads of protoplasm, or pseudopodia, locking and inter-locking with
one another (anastomosing); the same in kind, though differmg mark-
edly in degree, as the few coarse and short pseudopodia of Amoeba.
Then we cross at once to the class we have to deal with, the Radio-
laria, where the power lies of building up a skeleton of flmty matter
(silica) the same in chemical composition as the fine quartz crystals
from which much optical glass is made. But this spicular coating is
not essential to existence, for many-species (Collozowinv) possess none.
Let me therefore consider such an individual, which may be taken as
representing the fundamental or primitive type of Radiolarian, the
skeleton being an after assumption in the class, though in Collozowm
the absence is not due to primitive want of it, but rather to dege-
neration.

Comparing with Ameeba, we would say that in the Radiolaria
the body is nearly constant in shape to the globular form, and what
answers to the endosare of the other, is separated from the outer
layers by a membrane (chitonous 7?) which we term the capsular mem-
brane. This is pierced usually by numerous minute openings and
bedded in the protoplasm within the capsule (intra-capsular), lie
several nuclei—a characteristie of the group, and a very large oil-
globule.

The extra-capsular substance consists of two well defined layers,
the imner (sarcomatrix) which invests closely the capsule, is proto-
plasmic and granular; while the outer layer, the calymna, is of a
structureless, gelatinous nature. From this layer arises an often
wonderfully beautiful flinty (siliceous) skeleton, built up sometimes
as a lattice-work bell, or it may be into a lace-work globe with great
projecting spines. The calymna is penetrated by delicate tubules
through which pass fine threads of protoplasm originating from the
sarcomatrix. Having passed through the calymna, these threads pass
out on the surface of the globe into a network, the sarcoplegma, and
from this are projected into the water around, long filamentous
pseudopodia, closely akin to those of the Foraminifera. With these
long tendrils, prey is entangled and is then passed inwards.

The vast majority of Radiolarians—and their name is legion—
are such as we have described, but a small group live colonial lives,
numerous individuals massed in tiny communities, and modified in
certain points consequent upon the mutual duties devolving upon
the several individuals.

14, JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY,

Thus the individual skeleton is reduced and even lost. In
Spherozowm, each individual is surrounded by a lattice-work of loose
spicules of the elegant six-spined form shown at fig. E, Pl. I. In
other species, it is absent (Collozoui). Sometimes these colonies
reach considerable size. Collozoum attains a full inch in length.
Spherozounr is smaller and usually globular, perhaps +2-in. in length,
but sausage-shaped colonies of }-in. long are fairly common. 200 to
300 individuals are frequently associated together, bemg arranged
peripherally in a hollow gelatinous sphere, arising from the general
coalescence of the gelatinous outer extra-capsular layer (calymna)
of each member. This layer being common to all, it follows that the
protoplasmic network of the surface, and the radiating pseudopodia
are also common, ensuring the even distribution of nutriment. Thus
in a Radiolarian colony such as Spherozoum, we have each individual
with its own separate central capsule, its own separate sarcomatrix
and its own protecting lattice work of spicules; but calymna,
sarcoplegma and pseudopodia are shared in common by the colony.

If we examine carefully the sarcomatrix of Sphwrozoum, we see
a varying number of deeply stained bodies lyme irregularly spread in
the sarcomatrix of each individual. Some have many, some have
few, and it may happen that we may see some possessing none. In
life, these bodies are yellowish, and it is inferred that they are
parasitic, or, more probably, symbiotic alge. It appears that these
yellow cells can live equally well, and even multiply, when separated
from their host. Each has been found to possess a distinct cell-wall
of cellulose, a nucleus, two colouring matters, one of which is
chlorophyll, and lastly, to complete the vegetal characters, the power
of forming starch. They are present in nearly all species, though
some individuals are occasionally free from them. In the present
species, some individuals are crowded with them, while others have
comparatively few. These cells multiply within the host by the
division of their protoplasm into four parts which secrete separate
eell-walls and then break through the parent membrane. If removed
from the host, they eventually become biflagellate, a.e. provided with
two whip-like threads of protoplasm, flagella, their locomotive organs.
Some have referred them to a distinct genus of alge, while others
believe them to be the swarm spores of several species of olive-
green seaweeds (Fucus, &c.) It is probable that they assist in the
respiration and nutrition of their hosts, by contributing oxygen
and starch.

The reproduction of the Radiolaria is most intricate, and
betokens the high development to which the group has attained. If
we take a fully adult colony of phe noronn we find that the

MICROSCOPICAL STUDIES. 15

individual members, at a certain period, break up into innumerable
tiny spores; these spores may be of two distinct series. Thus one
colony may give rise to spores all of the same size, isospores, while
another may give rise by another method to spores of two sizes
(anisospores). ‘The former are probably asexual; the latter sexual,
giving a typical alternation of generation. Both forms are produced
within the central capsule. In the formation of isospores, the nuclei
of the parent multiply by fission and scatter throughout the capsular
protoplasm : each nucleus appropriates a certain amount of protoplasm,
and a minute crystal, and receives several tiny oil globules from the
breaking up of the great oil globule. When ripe, each of these
masses assumes a pear-shaped form, with the nucleus at the narrow
end, whence proceed two flagella which propel the spore through the
water, when liberated by the breaking down of the capsular membrane
and when disintegration of the extra-capsular matter takes place. —

Anisospores arise also from the multiplication of the mother-
nuclei, but the mode is somewhat different. Within the same
individual, two well-marked sizes oceur; the larger are termed
macrospores, the smaller microspores, and they escape in the same
way as do the isospores. Analogy suggests that in these macro- and
microspores we have a sexual stage, but the conjugation of these two
bodies, which is required to prove this theory, has not been observed.
The shape of both forms of anisospores is reniform (kidney-shaped) ;
they are propelled either by one or by two flagella. Isospores and
anisospores alike give rise to an ordinary Radiolarian having the
typical structure. This by fission of the central capsuce repeated
frequently, and by gemmation also (?), produces the coloniai mass we
have before us. Then when the full of adult life is reached, the
intra-capsular protoplasm breaks up into either iso- or anisospores.
The Life-cycle of such a Radiolarian can be tabulated thus :—

re

Isospore (asexual spore).

Young Radiolarian individual.

Colony (produced by fission and gemmation).

Anisospores = macrospores, and microspores (Sexual spores) (?).
Conjugation of macro- with microspore (?).

. Young Radiolarian individual.

Colony.

. Isospore (asexual spore).

Go WI ot BH bo

Stage 4 may not necessarily alternate with stage 8; indeed it is
probable, by analogy, that under favourable life-cond tions, the forma-
tion of anisospores seldom occurs—many repetitions of isospore
generations taking place before one of the anisospore stages recurs.
The latter probably occurs when new vigour requires to be infused

16 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

into the organism, cither through weakening occasioned by too frequent
repetition of the isosporulation, cr else from external life-conditions
of an unfavourable nature.

It is worthy of note that the tendency among colonial forms
is towards the suppression of a skeleton. Collozowm has none;
Spherozoum has loose spicules only. The reason probably is the
hindrance to the fermation of new individuals by the fission of the
central capsule, which a hard resistent casing to the latter would
entail. With loose spicules, if the central capsule divides, then each
half simply takes its share of the spicules with it.

Distribution. All latitudes know the Radiolarians, but they
abound most in the warm seas between the tropics. The majority
are pelagic ; Sphwrozoum and Collozowm among the number. Many
of the great depths of the sea are covered by ooze formed all but
entirely of their decaying remains, e.g. 2—3000 fathom depths of the
Pacitic and Indian Oceans. To other deep ocean oozes, the Red-clay
deposits, and the Globigerina-ooze, they contribute largely. The
familiar Tripoli powder, used for polishing, consists largely of their
remains; many fine whetstones are slaty rock formed in great part of
their siliceous skeletons. In many lands they largely compose
certain clays and marls, thus indicating, albeit in fragmentary
manner, the localities of uprisings of some ancient sea-bottoms of great
depths. Deposits in the Barbadoes and the Nicobar Islands, in
Algeria and Greece, are the best known of these—and it is from such
localities, especially from the first-named, that are obtained by careful
washing and separation, those beautiful fossil forms so well known as
microscopical preparations. These are all of Cainozoic age, but other
fossil species date from early Paleozoic times, while in Jurassic rocks,
they even form quartzite, so compactly are they knit together.

Stupy XV.—THE HypDRoID STAGE OF OBELIA GENICULATA.

Obelia constitutes a very typical form of Thecate Zoophyte, and
a study of the slide now sent out, taken im conjunction with reference
to Study XI, and Plate IX in last volume, will furnish materials for
a ready comprehension of the essential details of the anatomy and of
the life-history.

Stupy XVI.—THE STALKED LARVA OF ANTEDON.

Few of us are unfamiliar, at least by name, with Antedon, the
Rosy Feather Star. The extreme elegance of its long slender arms
has long made it famous among the artistic triumphs of the world of

MICROSCOPICAL STUDIES. 17

life, rivalling in slender gracefulness even the rare beauty of the
ferns. To those who have however seen it in life among its natural
surroundings, the charm deepens, and Antedon is for ever linked with
happy life-marks fondly remembered. Shall I ever forget that day
out lobster-potting with an old fisherman, when the first pot we
pulled up, was fairly encrusted with the rosy twining pinnated arms
of this most lovely of starfishes! Surely if the fisherman’s calling is
rough and uninviting at times, such experiences as these go far to
compensate. Rough fellows most are, but the sca has a silent
eloquence that finds its way to their hearts, and to those who have
served the apprenticeship, its fascination 1s magical; even J, who
have other pleasures, and have never been fairly inoculated, have still
at times to respond to the urgent calling of the sea.

Antedon is fairly common around the British Coast; in favorable
localities occurring in great multitudes. In anatomy it differs
extremely from the ordinary stout starfishes, such as the common ~
eross-fish Asterias rubens, but as we are not concerned at the present
with its anatomy, suffice it to note that its body consists of a disc
some 4 inch across, from which proceed ten long slender arms bearing
numerous pinnules on either side, these often reach 34 inches in
length so that the animal has a full span of 7 inches. The sexes are
separate, and the genital organs are located not in the body disc, but
in the tiny pinnules of the arms. ‘The fertilized ova are set free
as barrel-shaped embryos which acquire four encircling or zonal
bands of cilia—the hoops of the barrel—propelling it through the
water. Next appear a few minute calcareous plates within this
embryo, forming as it were, a tiny cask set up on an even more tiny
stalk. Free-swimming life being now all but ended, a disk containing a
perforated plate appears at the lower extremity of the stalk, and by
this, attachment is made to any object that happens in the way ; it
may be the stiff framework of a colony of Hydrozoa or of Polyzoa, or
it may be a frond of the great oar-weed (Laminaria). All this time
the soft barrel-shaped mass of the swimming larva has been shrinking
and adapting itself to the form of the enclosed calcareous skeleton,
and now the creature is fairly launched upon the stalked and anchored
period of its life.

In this stage the skeleton is made up of a basal plate (Pl. II,
fig. 2, t. pl.) where the animal is rooted to its host; a considerable
number of joints set end to end, forming the stalk, upon which
is seated the cup-shaped framework of the body, consisting of
two circles of large perforated plates, the members of each, superposed
to one another. These are respectively the basals (bs) and the
orals (or), the former forming the base of the cup, supported on

18 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

the summit of the stalk, while the orals are the upper ones, receiving
their name from their encircling of the mouth. All these plates can
be made out in the last stage of the swimming embryo (fig. 1) and
characterize the stage of most of the fixed larvee in the microscopic
preparations accompanying this article. A few however show a
further stage, where a third row of tiny plates is intercalated between
the two original rows of basals and orals; these small plates are the
first radials (7), each is alternate with the larger plates of the
skeletal basin. The several rows may be formulated thus :—

©® © © © ©
Eo eR a eaky
1} bj 18} 18} 183

Each ring will be noticed to comprise five plates, the fundamental
echinoderm index. The mouth, as before mentioned, is centrally
in the calyx formed by these perforate or cribriform plates, and
is surrounded by a row of tentacles armed with a limited number of
delicate thread-like processes.

Growth after this is rapid, a second circle of radials appears
superposed to the first and then a third upon the second. From the
third proceed the arms double the dex number, two being borne on
each third radial, which has two fascets for this purpose on its upper
surface. At the same time the topmost joint of the stalk has been
enlarging and becomes a great plate-like structure, the centro-dorsal
plate from which arise a number of claw-like jointed organs, the cirri.

Soon after this, the body with its now long arms, breaks off from
its stalk at a point just below the centro-dorsal plate, and enters
upon adult life, free at will either to creep amid the mud or
rocks, or to swim with rythmic beats of its long feather-like arms
through the water. It is however doubtful if it makes much use
of its powers. It certainly does not travel far from certain favorite
localities, where it is usually found gripping stones or weed with the
circle of hooked cirri borne on the centro-dorsal plate. When
disturbed, its mode of swimming is extremely graceful, the arms being
alternately contracted and expanded as in the pulsations of a medusa.

For long, the stalked larva was considered a distinct animal
from the adult, receiving the name Pentacrinus curopeus, as it was
believed to be a tiny relative of that large and lovely stalked crinoid,
Pentacrinus caput-meduse, from the Antilles, then known from rare
specimens held precious by a few fortunate museums. -

Special interest attaches to this beautiful creature from the great
part played by its relations, if not its ancestors, that lived during former
periods of the world’s history, for the Encrinites whose remains have

MICROSCOPICAL STUDIES. 19

contributed so greatly to build up the huge masses of our mountain
limestones, and many of our Jurassic beds, were but gigantic
Pentacrinoids of structure practically identical with the stalked larvee
of Antedon, that seem so like tiny attenuated Pentacrinoids,

Stupy XVII.—CRreEsEIs, A TYPICAL PYEROPOD. -

The struggle for mastery and bare existence gives many
unexpected results: we see the huge monsters of ocean, not of
true finny lineage, but interlopers from the land; we see the cousins
of our starfishes and sea-urchins, taking on the outward form of
burrowing worms; insects become, in appearance, indistinguishable
from sticks and leaves; birds leave their kingdom of air, and pursue
their livelihood amid the waters, seeking prey by diving and swim-
ming; but perhaps stranger than all, the butterflies of ocean, whose
winged and shimmering myriads are familiar to voyagers on the high
seas, are nowise akin to the gaudy visitants to our flowers; neither
have they relationship, as we might excusably guess, with the great
group of the Crustaceans. The latter, diverse as the insects in habit,
and ready as they, to change form, and to adapt themselves to any
new life where there may be a prospect of easier existence, yet put in
no claim to the title, and it is reserved to the humbler molluses—to
creatures allied to the slow creeping snail, and lethargic limpet—to
furnish representatives charged with the duty of peopling the waves
with gay flutterers. Yes, the Pteropods, as the Butterflies of the Sea
are called, are undoubted molluscs, closely related on the one hand to
such Gastropods as the snail, on the other to the Cephalopods—the
Octopus and Cuttlefish. But before discussing their place in Nature,
let us examine the anatomy of the typical form, Creseis acicula
(Rang), which is the subject matter of this paper.

Creseis is the most slender, but not the shortest of Pteropods.
The body is lodged in a delicate needle-shaped shell (whence the
name acicula), not #-in. in length. This shell, transparent and
colourless, and composed of carbonate of lime, is very gradually
tapered and extremely narrow, even at the broader end. The pointed
end is closed, while from the other protrude two tiny wing-like fins,
the means of locomotion—hence the significance of the term Pteropod
or “ wing-footed.” Coinciding with the form of the shell, the body is
greatly elongated, especially that part lodging the central portion of
the viscera—the visceral hump or dome, which is spoken of as the
upper end of the animal (see last paragraph of this article). The
shell is lined and produced by a fold of the body-wall, called the
mantle, between which and the body, a large space, the mantle cavity,

20 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

is formed, lying on the posterior aspect of the body, and opening to
the exterior by a slit at the ventral end, 2.¢. at the mouth of the
shell.

There is no distinguishable head, and of head appendages only
two tiny, easily overlooked, tentacles lying just behind the fins.
These have evidently suffered degeneration, showing in their minute
size, and in the tiny eye-speck at the tips, but little resemblance to
the great organs so familiar upon the head of the snail.

Two slight eminences guard the entrance to the mouth. Within
this a radula or teeth-bearing ribbon is found, whence a long
cesophagus leads straight backwards or rather upwards, ito a dilated
stomach. The intestine is continued backwards for some distance,
then abruptly turns and passes forwards (downwards) to open laterally
into the mantle cavity at a point on the left side.

Lying close to the intestinal bend, is the anterior end of the
enormous sausage-shaped secretive organ which for convenience we
may term liver (/). It rans backwards parallel with the anterior
half of the ovo-testis.

As regards muscular tissue, such is developed sparsely except in
the fins, and in a great strand of fibres that originates from a point
only a little below the apex of the shell, runs parallel with the
ovo-testis and liver, thence forward and to the night, to the oral
end of the body, and to the copulatory organs. Its name, the
retractor muscle, denotes its function.

On the right side, in the region of the intestine, lies an elongated
cylindrical organ, the nephridium or kidney. This has at one
end an opening communicating with the exterior, while at the other
—the end turned towards the apex of the visceral hump—a passage
is found leading into the pericardium. Probably this is a means for
introducing sea-water into the blood at stated mtervals, thus giving
an additional and interesting function to the nephridium.

The heart, lying dorsal, to the nephridium and like it on the
right side of the body, consists of a globular ventricle and of a
delicate auricle. From the former a large artery is given off, leading
into several smaller branches. These however, instead of in turn
leading into capillaries and thence into veins, open into an irregular
chain or network of indefinitely shaped spaces Cacune) disposed
in the tissues, and without definite walls. From these the impure
blood is gathered into a large venous or pericardial sinus, whence it
is passed into the auricle.

(1). To arrive at the right application of the terms dorsal, ventral, anterior, and

posterior, to the body of a Pteropod, one must picture it as in fig. G, Pl. III, the
mouth downwards and the apex of the shell directed upwards.

MICROSCOPICAL STUDIES. 21

The respiratory region in this species lies on the inner side of
the mantle, therefore on what is apparently the ventral aspect of the
animal, but which strictly is the posterior. In some species the
general surface of the mantle functions, but in this, the chief seat of
respiration is a shield-shaped area in the region of the stomach,
where the mantle is thrown into curved and transverse folds, bearing
cells richly ciliated, whereby the water is kept continuously in
motion.

The central mass of the nervous system is formed by the
concentration of three pairs of ganglia around the anterior end of the
cesophagus; that part lying above, representing the supra-cesophageal
ganglia; that beneath, of two pairs, named respectively the
visceral and the pedal ganglia. Nerves going to the mantle and
to the alimentary organs can readily be traced proceeding from the
hinder part of the nerve-mass, but in size, these are far surpassed by
two enormous nerves (7. 7.) given off, one on either side, by the pedal
ganglia, for the nerve supply of the swimming fins. Each on entry,
throws off a smaller branch, and then proceeds to give off with
remarkable regularity, some 20 pairs of lateral nerves at short
intervals. Each pair consists of a right and a left nerve originating
from the same point. The same arrangement is repeated by the
smaller branch.

For so small an animal, the reproductive organs are extremely
complex and are complicated by the creature, like all Pteropods, being
hermaphrodite. Ova and spermatozoa are produced in the same
gland, the ovo-testis or hermaphrodite gland. This hes, as a compact
elongated mass, in the hinder (dorsal) end of the body, parallel with
the liver. It is connected by a fine efferent duct with the sexual
orifice which opens on the right side just dorsal to the base of the
right fin. Connected with the lower end isa side pouch—the uterine
cecum. Another pouch-like organ of equally great size, opens close
by the genital aperture, and just at the base of the right rudimentary
tentacle (p. g.) This is the invaginated (indrawn) penis or penial
gland, the external male sexual organ, highly specialised as in the
gastropod molluscs, and here as in other Pteropods, of very large size.
The spermatozoa pass from the common sexual orifice to the penis by
a short ciliated external gutter or furrow (e. f.) Self fertilization is
obviated by the male and female elements maturing at different
periods. When copulation with another individual takes place, the
great penis is evaginated and inserted into the uterine cecum, the
spermatozoa pass in, and thence are conveyed to a small vesicle, the
receptaculum seminis, there to await the arrival of mature ova from the
hermaphrodite gland. When this occurs, the sperm escapes from its

22, JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

confinement and fertilizes the ova, which are then ejected in long
gelatinous cords that float hither and thither at the mercy of the
waves till hatching takes place.

Adult Pteropods all progress by jerky flappings of the wings.
Agassiz says they can remain suspended in the water for hours,
simply by spreading these wings, and then suddenly drop to the
bottom by folding them. They are also said to creep about by means
of these same appendages.

The group of Pteropoda is not large, and its members fall
naturally into two well marked divisions—those like Creseis, with a
well developed shell, form the order Thecosomata; those naked and
without shell, the Gymnosomata, Few are ever seen near land, they
prefer the high seas, and are spread under all latitudes, little more
plentiful in the Tropics than in the Northern regions of Baffins Bay
and Davis Strait and the Polar Sea generally—where indeed the
multitudes of two species, Clione borealis and Limacina arctica,
form a substantial item in the dietary of the whale.

In considering the place in nature of these animals, the possession
of an odontophore (lingual ribbon or radula) at once discovers their
close relationship to the Gastropods and to the Cephalopods, and with

these and the little group of Scaphopods (Dentaliwm), form the com-
pact branch, Glossophora, (“tongue-bearers”), of the phylum Mollusca.
(a) In the arrangement of the genital system, the Pteropods are
extremely like many forms of hermaphrodite Gastropods; the snail
and the sea-slug (Aplysia) for example, agreeing closely in all the
larger details, while in this, they differ markedly from the Cephalopoda,
where the sexes are always separate. (b) Outwardly usually bilaterally
symmetric like the Cephalopods, Pteropods are all fundamentally
asymmetric, and here again approach to the most usual Gastropod hike-
ness, for as in the latter, both the anus and the sexual organs are lateral
and asymmetric, the one in Creseis being tuned to the right, the others
to the left. (c) A third link with the Gastropods is found im the
possession by certain genera (Spirialis) of an operculum. (d) On
the other hand, Pteropods of the shell-less group, have processes
developed from the “head,” of arm-like form; in some cases even
bearing suckers—a wonderfully close approach in appearance to the
familiar arms of the Octopus and the Cuttlefishes. So close, indeed,
is this resemblance, that Prof. Ray Lankester has not hesitated to
class both Pteropods and Cuttlefish in one all-embracing division, the
Cephalopoda, forging a new term, Siphonopoda, for the diverse com-
pany of the Octopus, Nantilus and Cuttles. Such considerations as
a b and ¢ make against this view, and it is significant that the nerve
supply to these head-arms has different origin in the two divisions,

MICROSCOPICAL STUDIES. 23

being supplied from the brain (cerebral ganglia) in the Pteropods,
and from the pedal or foot ganglia in the Cuttles. Hence it seems
much more likely that the resemblances between the Pteropods and
Siphonopods are rather homoplastic than homologous, 2.¢., have arisen
independently rather than being possessed of common origin. Like
circumstances not infrequently produce analogous shapes and organs
in animals of distant relationship, and the case in point is probably
of this nature. It is to be remembered too, that it is only the division
of shell-less Pteropods that m any way simulates the appearance of
the Siphonopods; the shell-bearing forms (Thecosomata), such as
Creseis, are very closely approximated to the Gastropods in all details
of organization. Thus we may conclude that the Pteropods are a
branch from the Gastropod stock, modified by pelagic habit, and im
some respects even degenerate (i.e. degenerate from the stand-point
of the Gastropod) and having their most specialized members approx-
imated in outward form to the Siphonopod type. As to this latter
designation, it appears thus more fitting to displace it and to restore
the term Cephalopoda to its older and more restricted. meaning
whereby it is applicable to the Octopus class alone.

The diagrams Pl. III, figs. D to H (modified from Lankester)
show graphically the mutual relation and modification of the several
parts of the body as seen among the principal types of Glossophorous
Molluscs. Fig. D shows a simple type of Gastropod, such as Chiton,
where the mouth and anus are at opposite ends of the body, the foot
large and extending the whole length of the body on the ventral side,
while the central part of the back is more or less humped—forming
the visceral hump or dome, as in it most of the viscera are lodged.
Fig. EK indicates the modifications in the relative arrangement of parts
due to the bending and coiling of the visceral hump, as seen in such
Gastropods as the snail and the whelk. G and F represent respec-
tively a shell-bearing and a naked Pteropod, and show how in these
animals the visceral dome is much elongated and drawn out, causing
thus a great bend in the alimentary canal. The foot in both is
represented by little else than two wing-like fins, believed to arise
from two lateral flaps—epipodia—of the middle division of the foot.
In several Gastropods, such flaps are well developed; thus in the
sea-slug Aplysia, they rise from either side of the foot and fold over
the back. In F, the “head-arms” or “buccal cones,” that are so
curiously like the arms of Cephalopods, are represented, but are not
here shaded similarly as having a like origin for the reason already
_ given.

Fig. H is a diagram of a Cephalopod given for comparison.
Here part of the epipodia (?) form arms beset with suckers in place
of swimming fins, while the funnel is also formed from part of the

24, JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

ancestral foot. The figures also illustrate the true application of the
terms dorsal, ventral, anterior and posterior to the body aspects in
Pteropods and Cephalopods.

It may now be useful to show in tabular form, the place assigned
to the Pteropods, in the phylum Mollusca, and to give a summary of
orders and other divisions :—

Phylum :—Mollusca.

Branch A :—Glossophora. | Branch B :—Lipocephala.
(possessing a radula). (without radula & without ‘“ head.’)
Class I.—Gastroropa (types— Whelk | Class 1.—LameLiiprancuiata (types —
and Limpet). Mussel, Oyster, Cockle).
« II.—ScapHopopa (type — Denta- Tr
liwm).
“ JII.—PrEropopa (types — Creseis
and Clio).
‘6 TV.—CEPHALOPODA (type — Octo-
pus).

Pteropoda,
Order I—Thecosomata; body protected by a shell.

Family I:—Hyaba1p, shell calcareous or horny, symmetric. Types—
Hyalaea (horny) ; Creseis (calcareous) ; Cleodora.

Family II :—Cymputinipm, shell slipper or boat-shaped and with some
short “‘arms. Types—Cymbulia and Tiedemannia.

Family II] :—Lrvacinipz. Type — Spirialis, with spirally coiled shell
having sinistral flexure, i.e. coiling in the reverse direction
to that usually seen in Gastropod Shells.

Order II.—Gymnosomata ; body naked.
Family I :—Ciionin®, without gills, but with short arms devoid of suckers.
Type—Clione (Clio) borealis.
Family II :—PNrEUMODERMONID, with gills at apex of body, and with arms
beset with suckers. Type—Pnewmodermon.

Cleodova pyramidata is phosphorescent and probably others
are also. In Cymbulia, the small chitonous shell is internal. Spi-
rialis is the most closely related to the Gastropod form, its pecu-
liarities extending to the possession of both: a spiral shell and an
operculum. The larve or veligers of Cymbulia and Tiedemannia
also possess opercula.

Tiedemannia, like the Cephalopods, possessed well developed
pigment-spots (Chromatophores) on the surface of the body, doubtless
a protective device.

DELAY IN IssuE.—The Editor extremely regrets the delay that has occurred in
the issue of the present number. The causes have been several, the chief being
that since the last issue, Mr. Sinel’s assistance has been lost to the Station, through
his acceptance of the management of an Oyster Culture Company now established
in this island. This has naturally thrown much extra work upon the writer, but he

believes that the new arrangements he has made, will obviate any similar delays in
the future.

Che Hounal of Marine Soology
and Sievoseopy :
A PLAINLY WORDED BIOLOGICAL QUARTERLY.

You. Il. No. 6. OCTOBER, 1895.

SPIRULA PERONII, Lam.

SB Yo HARUN HS El. in SICH WiPAsky Zi. WAG jE C79".

From the Geological Research Laboratory, Royal College of Scrence.

VERY one who takes an interest in shells is familiar with the
little “ Post-horns,” as the shells of Spwrula have been named ;
they are found in vast quantities on most of the shores of the
Southern Seas, some even, as Mr. Hornell tells me, finding their way
to the shores of Jersey, while in France they are reported from
La Rochelle and the bay of Gascony; but the animal is known from
only a very few imperfect specimens. We have here the case of a
deep-sea animal, living, we know not where, im countless thousands,
casting its shells over the entire world, in most cases far from its
natural habitat: and supposing these shores in the future ages to
become covered with sediment, it might, with apparent justice, be
inferred that the animal had a world-wide distribution, which is not
the case: and we actually do find similarly constituted shells, the
Ammonites and the Nautili, massed together in bands in various
strata, and wherever we find beds of an equivalent age, no matter
whether they are as distant as the poles, we find, species for species,
the same fauna, and our little Spirula gives us a clue as to how this
has come about,

So long ago as 1705, Rumphius® gave an account of the living
Spirula, but the first clear description of the animal was by
Lamarck®) (who gave it the specific name of Peroni) and Péron™ ;
these two established the fact that the arms bore suckers, while
de Blainville® pointed out that it belonged to the class Decapoda
a deduction which was confirmed by Gray and Lovell Reeve from

(1). Wurtenburger, Studien weber Stammes Geschichte der Ammonit., Leipzig,
1880 ; also Lindstrém, Konigl. Svenska Vetenskaps Akad. Handlin., No. 12, p. 4, 1888.

(2). D’Amboinische Rariteit-Kamer, p. 68; translation by Miller, Vienna, 1765.
(3). Encyclopédie Methodique, pl. 465, fig. 5; Mem. Soc. d’Hist. Nat., 1799.

(4). Atlas du Voyage aux Terres Australes, tab. xxx, fig. 4.

(5). Annal. Frangaises et Htrangéres d’ Anat. et de Phys., vol. 1, p. 869, 1837.
(6). Ann. and Mag. Nat. Hist., vol. xv, p. 257.

(7). Elements of Conchology, p. 16.

26 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

an examination of the entire animal of Spirula australis from New
Zealand, taken by Mr. Earl, and now in the National Museum. In the
Buffon de Sonnini, Péron’s specimen was exactly described by
Roissy, but afterwards this priceless treasure was lost. On the
voyage of the Samarang, a mutilated specimen was cbtained by
Sir E. Belcher in the Indian Archepelago, and was handed to
Sir R. Owen for dissection, forming the subject for a short memoir by
the latter, wherein he establishes a third species, S. reticulata, from
the peculiarity of its skin; this latter came from Tamor. Lastly, a
good specimen was dissected by Professor Huxley, but we have yet
to await the published description.

The body of the animal is cylindrical, compressed laterally, with
the head about twice as long as broad: at the hinder end, enclosed in
the mantle, is the small coiled shell which in all known specimens is
visible on the dorsal and ventral portions, where it is covered only by
a thin membrane. The head is not constricted externally from the
body, and bears two eyes, eight short tentacles, and two long ones,
probably expanded into two lobes like in Sepia. The infundibulum
or funnel is entire, not, as in the Nautilus, divided down the middle,
and bears a terminal valve; just behind it, lodged in the cartilaginous
cranium, are the two capsules containing otoliths, said to function as
hearing organs. ‘The branchial chamber has no septum as in the
Octopoda, and the gills, two in number, are elongated, narrow-
triangular in form, each consisting of about 24 folds, and bearing at
the base a branchial heart with an appendage attached. The liver
consists of two lobes; through the interspace thus formed, the
oesophagus, aorta, and visceral nerve pass; the relation of the inkbag
and generative organs, in like manner, resemble those of Sepva.
Whatever the soft parts may teach us, it is to the shell that we must
look if we wish to understand the place of Spirula among other
Cephalopoda, the vast majority of which are only known to us by
their hard parts.

Of the shells there are many apparent species, but on examining
a large number, these sink into merely varietal significance, and the
authorities of the British Museum acknowledge only one species,
S. Peronii, Lam. The differences as far as I can make them out
are: 1, the thickness of the shell; 2, the figure of the transverse
section, some being circular, others strongly depressed and oval ;
3, the amount of evolution, in some the whorls touch, in others they
are widely separated; 4, the presence or absence of a keel on the
inner side of the first whorl; and 5, the size and shape of the first
chamber being often spherical, egg-shaped, or drupe-shaped.

(8). Zoology of the Voyage of H.M,S. Samarang, Mollusca, p. 6, 1850.

SPIRULA PERONIL. Dall

The most instructive way of examining the shell is to cut a thin
section passing through all the whorls in the plane of coiling, whereby
the structure of the walls and septa, as well as their mutual relation
is well exposed. As far as I know, such a section has not been
figured or described; it is exceedingly difficult to accomplish, and
requires the sacrifice of many specimens. The best way to do it,
is to take the shell just as it is, lay it on its side on a keen, perfectly
flat Water-of-Ayr stone, and rub it carefully till the middle is
reached; mount it then direct on the glass slip with hardened
balsam, and rub the other side down till the requisite thinness is
obtained. In putting on the cover-glass, drop some hot balsam on to
the slide, and do not warm it in the usual manner, as the whole thing
will float away in pieces.

The walls of the shell are formed of two layers. The inner
consists of a semi-transparent, porcellanous material with a steep
imbrication, that is, it appears to be made up of layers which are
inclined at a gocd angle with the surface. It has no trace of
prismatic structure which would homologise it with the inner,
mother-of-pearl layer of the Nautilus and the Ammonites, but
resembles rather the outer granular layer of these though the granules
seem arranged in fibres which are extended at right angles to the
surface. Hach layer readily splits away from its fellows and the shell
consequently is very brittle but breaks reguiarly in rings correspond-
ing with the lamine.

The outer layer is clear and glassy, and is riddled through with
little tubules running parallel to the surface on which they frequently
open, thus giving the shell the roughness which has caused the term
“shagreen” to be applied to this layer, and which Sandberger
homologises with the peculiar wrinkled layer found between the
whorls of some Ammonites, and which is similar in position to the
black layer of the recent Nautilus; at any rate, it has nothing to do
with the shagreen on the shells of the Decapoda which consists of a
deposit freely poured out and hardening in spherulitic knobs,

The septa are truly prismatic, and the shell-substance is identical
with that forming the septa of Nautili and Ammonites; at the outer
periphery they expand somewhat and the successive layers of which
they are composed are separated, while a prolongation of the inner
layer of the shell-wall covers the wpper surface for a short distance.
This latter fact, showing that the imner wall was formed after the
completion of the septum, proves that the septa are not morphologi-
cally equivalent to those of the camerated shells (Ectocochlia). On
the under surface there is a grey-looking deposit, constituting a half

(9). Verstein, Rhein. Schicht. in Nassau, 1858, p. 58.
(10). Moynier de Villepoix, Jowrn, Phys., Paris, 1892, p. 618.

28 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

false septum, beneath this again 1s an axillary deposit. On the inner
side of the shell the septum bends down to form the septal funnel
which reaches the preceding septum, thus making a closed tube; at
the end of the funnel there is a ring of denser shell material just
as in the short funnels of the recent Nautilus.

iain
Za

ties
ES Sei Sx

ME aS
i}

a3
i

or SS

La DEASIOC Tiare a

ankar

ahs
rey

>
beet A
—

i)
orEP
ee

Fig. 1. Section through the shell of Spirula Peroni, Lam.: a, Inner
fibro-granular layer, covering the septum, ¢, by the pro-
longation, g; 0, outer transparent layer; d, false septum ;
e, axillary deposit; f, ring of dense shell material at the
end of the siphonal funnel; h, deposit of transparent
material between the end of the siphonal funnel and
septum ; the letter /, is placed in the siphonal cavity, a, in
the air-chamber.

Figs. 2 and 3. First half whorl of Spirwla, showing in one case the
oval ovicell like in Bactrites and Gomatites compressus ; in
the other the short spherical one as in other asellate
Goniatites and Orthoceras.

Figs.4and5. After Amos P. Brown. Fig. 4, protoconch of Ammonites
as usually figured; Fig. 5, protoconch of Baculites com-
pressus, Say, showing the extension of the shell in front of
the first septum.

(11). Brooks, Proc. Boston Soc. Nat. Hist., vol. xxiii, p. 380.

SPIRULA PERONII. 29

Let us now turn from the section to the first chamber. This, as
I have said, consists of a small rounded body bounded on one side by
the first septum, through which bulges the end of the siphuncle or
fleshy tube, contained within the septal funnels. Munier-Chalmas(@2)
has described a little membraneous tube which stretches through the
empty chamber and forms a prolongation of the siphuncle, which he
calls the prosiphon. I have soaked the first chambers of several
specimens in refractive media, so that they became transparent,
and have also broken open some with needles, but I have failed
to see this prosiphon which thus apparently can only be seen in
exceptionally preserved specimens. It is also said to occur in the
first chambers of the Ammonites.

I have purposely not called the first chamber the protoconch, by
which it is usually known, because there are three distinct things
united under the name. First, there are the primary chambers of
the Ammonites, to which I propose to limit the name protoconch.
These are little miniatures of the adult, within which the first
septum is formed ; the walls are continuous with those of the succeed-
ing chambers“),

Secondly, there are the forms exemplified by the first chambers
of Spirula, Belemnites, Goniatites (Mimoceras) compressus, and the
lately described form of Othoceras“, for these I propose to revive the
term “ ovicell,” because they stand in the same relation to the adult
as the egg-shell does to the bird. In these the form is inflated and
sharply constricted off from the succeeding chamber, with whose
walls it is not continuous; the first septum is found at the apex, and
not within the chamber. The embryo, in emerging, apparently
gnawed a hole in the egg out of which it squeezed, and reared the
adult shell with this as its basis. As the above mentioned Othoceras
teaches us, the Nautili had eggs of this sort, but they usually
discarded them; in some it seems to have been retained for a con-
siderable time, and the place of attachment is marked by a scar, as
in the recent Nautilus; but in others, often closely related to forms
with the cicatrix, the apex is smooth), showing that in these the
animal must have lived some time in a naked state, as the more
highly organized Ammonites certainly did.

Thirdly, there is the type exhibited in Nanno (Endoceras)
belemnitiforme, Hohn@®, which is of such a size that in cross section
it is more than half the size of the adult. Now we know that among

(12). Comptes Rendus, vol. xxvii, 1873, p. 1557.

(13). Brown, Proc. Acad. Nat. Sci., Philadelphia, 1892, p. 189.

(14). Clarke, American Geol., vol. xii, 18938, p. 112.

(15). De Koninck, Calcaire Carbonifére, Ann. du Mus. roy. de Belgiqae, 1850.

(16). Hohn, Dames and Kayser’s Pal. Abhandl., vol. 111, 1885 ; Clarke, Amer.
Geologist, vol. xiv, 1894, p. 205; Bather, Nat. Sci., 1894, p. 422.

30 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY. »

birds, for instance, the Kiwi lays an egg almost as disproportionate,
but considering the mode of parturition in the Cephalopods, it is
improbable that this is the true size of the embryo. In this the
animal must have emerged from the egg and swam about naked till
it assumed nearly its adult size, so that the first chamber here
represents one of the chambers in the middle of an Orthoceras shell:
possibly, the earlier shell was once present, but was cast off, as 1s so
commonly the case with these early Nautiloids. The inflated end of
the siphonal tube has no claim whatever to be called a protoconch,
since it is homologous with the little bulging portion at the end of
the siphuncle in Sprrula, and contained within the ovicell.

Spirula, then, is in its anatomy closely related to Sepia: its
protoconch tells us nothing, since forms widely separated possess
identically shaped ones; the structure of the shell proves it to be
unique among shells yet described. If it occurred in ancient strata
then we might have considered it closely related to Nautilus, as
Linnzeus and Cuvier did (by the former, it was named Nautilus
sprrula), and then, by the formation of a deposit cn the under surface
we should pass to Spirulirostra, then by the straightening of the
chambered portion we should derive the Belemnites; but though in
a recent authoritative article this descent was actually insisted upon,
the Belemnites occur first in the earth’s history, and the Spirula
last, so that with the evidence at present available we must reverse
the process, and derive Spirula from the Belemnites through
Sprrulirostra.

THE WORK OF THE JERSEY BIOLOGICAL STATION
DURING 1895.

In most respects progress has been extremely gratifying this
season, and the number of workers using the Laboratory has in-
ereased to an extent beyond anticipation. To meet the consequent
need for greater accommodation, the room used as a type Museum,
has been altered in such manner that while still available for the
original purpose, the addition of a laboratory table, with shelving,
gas and water supplies, sinks, &c., enables it to be used as a first-
class and roomy Research Laboratory.

The list of workers, who, during the past summer, have testified
by their presence to the value of the Station from the purely
scientific standpoint, comprises the following, arranged according to
the respective dates of laboratory occupancy :—

Mr. —. BowbeEn, St. Bartholomew’s Hospital.—General.

Mr. —. Prarce, St. Bartholomew’s Hospital.—General.

Mr. Hy. Scuerren, London.—Amphipods.

Prof, HzrpMman, Liverpool.—Oyster-cultivation and Tumcata.

Mr. A. Epmunps, King’s College, London.—General.

Mr. Hy. Hanya, Queen’s College, Belfast.— Methods of preservation of Marine Animals.
Mr. R. Arnorr Staia, New School of Medicine, Hdinburgh.—Laboratory methods.
Mr. H. T. Mettor, Owen’s College, Manchester.—General.

Mr. J. H. AsHwortH, Owen’s College, Manchester.—General.

Prof. MaIsoNNENUE, Angers.—General.

Dr. W. B. Benuam, Oxford.—Nervous system of Polychaeta.

Mr. J. C. Srocpon, Budleigh Salterton.—General.

Mr. H. C. KE, Zacwartas, Berlin University.—Rotifers and habits of Marine Animals.
Dr. J. Justus ANDEER, Paris.—Ewtirpation of organs im Fishes,

Mr. H. Frrvurr, Guernsey.—General.

Few of these have occupied tables for less than a month each,
and while all have expressed themselves highly satisfied with the
arrangements for work, one, Mr. H. C. E. Zacharias, has been so
greatly impressed with the richness of the littoral and the facilities
for research, that he has arranged to occupy a table permanently,
with the view of continuing his investigations of the habits of marime
animals. As Research Assistant, he will also devote a considerable
portion of his time to morphological research upon some of the rarer
representatives of our Fauna.

Many other Biologists, including a number of French and Swiss,
have also paid flying visits to the Station during the summer, and it
is gratifying that there has been great unanimity in their praise of
the practical and useful arrangement of the Station. From the
promises to return to work in the Laboratory at a future date, a
busy summer is augured for the coming year.

As regards the supply department, the present year has been
one of transition. The arrangements I made last spring did not

fulfil my expectations, and in consequence, I have been compelled

82 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

to resume the entire charge of all conservation work. With the
extra time which I shall be able to devote to this in future, I can
confidently promise that all material sent out from this date will be
as nearly perfect as it is possible to attain. In this connection, I
may mention that I have been experimenting largely for the last
six months, with Formalin as a preservative medium, and I shall
take an opportunity in the next issue of this Journal, to detail fully
my methods and the chief results obtained, in the hope of thus
helping workers at other Biological Stations.

I greatly regret one circumstance in the year’s work, namely,
the delay in the issue of the present number. I trust, however,
that the friends of my work will bear with me patiently, and
remember that in this enterprise I am engaged single-handed, and
that the entire labour of the sketching out and final drawing of the
plates, together with that of the articles connected therewith, falls
upon my shoulders solely. In conjunction with the responsibility
and time taken up in the busy summer in the active direction of the
Station, such work has been almost too great for me and at times
I have been tempted to regret the inception of the enterprise.
However, I shall struggle on, in the hope of being able to recover
lost ground, now that the long evenings of winter are coming to my
aid. My friends must bear in mind that these literary labours are
of themselves absolutely unremunerative, and that I can only afford
to continue them by stealing the necessary time from hours which
by right should be devoted to relaxation. Those whose sympathy
is not wide enough to influence them to extend their patience
towards me, must perforce cease subscribing. I esteem my sub-
seribers my friends, and if they are not my friends, I would prefer
that they should not be subscribers.

FISHERY WorK.—Under Mr. Sinel’s fostering care, the Oyster-
parks recently constructed at Green Island (S.E. coast of Jersey) are
now in a flourishing condition, Phenomenal growth has taken
place—“ seed-oysters ” of 1 to 14 centimetres in diameter, laid down
on June Ist, have now (Sept. 30) attained a diameter of 34 to 4, and
even 43 centimetres. ‘The increase in weight is proportionate, as
5-lbs. of “seed” has in the same time increased to 18-lbs.—fully
demonstrating the forecaste made of the suitability of the Jersey
littoral for the remunerative rearing of this mollusc. Further
ground is being taken in to form other parks, and the success of
this new undertaking is assured.

Besides this practical outcome, the Station’s influence is bemg
felt generally in the more living local interest that is springing up
in general fishery matters, and I hope to have further direct progress
to report shortly.

STATION'S WORK. 30

Among other lines of research, I have been, this year, pursuing
investigations upon the difficult bait problem, and have had, within
the last few days, an apparent partial success—a result somewhat
unexpected. It will however be a considerable time ere I shall be
in a position to publish results, as the Station being without subsidy
of any kind, i can with difficulty spare the time and incur the
expense needful for such experiments. J. HoRNELL, Dvrector.

BOOK NOTICE.

“ Popular History of Animals for Young People,” by Henry Scherren, F.Z.S.,
376 pp., 13 coloured plates and woodcuts in text. (London; Cassell & Co., a,
1895). Price 7s. 6d.

Unusual activity exists at the present day in the production of Popular Natural
Histories, and though it may seem difficult to break comparatively new ground, yet
Mr. Scherren undoubtedly does so in the direction made plain by the title as above.
Tt is scientific Natural History written down to the comprehension of youngsters,
and in every way the yolume is satisfactory. The facts are well selected, well
connected, and ably presented in simple telling language, and in the handsome
dress in which Messrs. Cassell present it, it is just the book to awaken or strengthen
a genuine love for animal history among our younger friends. It is refreshing to
note that marine invertebrates are not neglected and thrown aside as beneath the
notice of ordinary nature lovers but are accorded over 30 pages of first-class matter.
This out of a total of 368 is something to be thankful for. Even a woodcut of
Balanoglossus is given. The thin end of the marine Zoologist’s wedge has evidently
been inserted !

My.
Mil Vsp>

\-

We
: a

TUBE-FORMING AMPHIPOD, AMPHITHOK RUBRICATA,

An exhaustive index is a valuable feature, and as befits its character, the work
is profusely illustrated. Many of the woodeuts are old friends, but they are all
suitable, and it is satisfactory to note that a fair proportion are original and accom-
panied too, by notes culled from the author’s personal observations. By the courtesy
of the publishers, we are enabled to reproduce cne of the most interesting of the
former. It represents the mucus-lined tube built by an Amphipod (Amphithoé
rubricata, Montagu) in a small aquarium belonging to the author, and the interest
is the greater, as the animal sketched was one of several sent by the writer to
Mr. Scherren some few months ago. J. H.

MICROSCOPICAL STUDIES IN MARINE ZOOLOGY.

BY JAMES HORNELL.

Stupy XVIIL—THE CoryNIDz.

The family Corynide, in its inclusion of the two distinctive
genera Coryne and Syncoryne, furnishes a perfect object lesson in
the gradations of development that prevail among Hydroid Zoo-
phytes; ranging from that fullness of development characterized by
definite and distinct Hydroid and Medusoid stages, down to the utter
suppression of the latter stage and its replacement by what are mere
sessile bags containing the reproductive elements—degeneration of
the most marked description. Such gradations are always of great
interest and value to the evolutionist, for though the series is
one of degeneration rather than of progress upwards, still, it bears
conclusive evidence of the readiness and ease with which organisms
can undergo radical alteration in vital and conspicuous organs, and if
a species can so easily retrogress, the inference that others may as
readily advance by the elaboration of new organs, is logical and
reasonable.

Intimate knowledge of a representative species in each of the
two genera referred to, is readily obtained, for both Coryne and
Syncoryne are present on many parts of the British Coast.

Syncoryne, which, of the two, has the more typical life-cycle,
grows in littoral pools in low bushy colonies, comparatively little-
branched, and with a creeping stolon connecting the various main
stems. The latter, in S. exvmia, are brown and horny, and annulated
only towards the base ; the twigs on the other hand are closely ringed,
transparent and colourless.

The polypites are not seated in cups at the extremities of the
branches as in Obelia, but are naked and without any protective
envelope into which they can retract upon irritation. As a natural
compensation, or rather adaptation, the polypites are much larger
and stouter, and their tentacles better equipped with stinging cells.
Some slight suggestion of a cup is, however, present, as the edge of the
chitonous tube which forms the branchlet is expanded slightly as a
very delicate tiny chalice at the very base of the polypite. It is
however of absolutely no use as a protective sheath, both on account
of its extreme thinness, being cuticular rather than horny or chitinous,
and on account of small size, only 3th of the length of the polyp.

MICROSCOPICAL STUDIES. 35

Indeed in specimens mounted in balsam, it is so transparent as to be
most difficult to see. The polypites, while possessed of as great
retractile power as those of the Thecate Zoophytes, have not the
same rapidity of movement, and answer to a stimulus or irritation
much more slowly.

Among the Calyptoblastic Hydroids, the pydranth or polypite
is usually cup-shaped, with the tentacles arranged in one or more
rings around the mouth. In Syncoryne, the body is as a rule
spindle-shaped, though by elongation it may at times appear almost
cylindrical ; while the tentacles are disposed irregularly over the
whole surface, standing out stiffly, so many spikes on a war-club.
The form of the tentacles, too, is peculiar, each being swollen at the
extremity—capitate—a characteristic shared by Syncoryne and
other members of the family. The reason for this capitate form is
not far to seek: it owes origin to the peculiar grouping or massing
of the nematocysts at the apex—a striking divergence from the
prevalent arrangement among other families, where the collections or
batteries of stinging cells are situated at intervals on the general
surface of the tentacles. It is interesting to note that the tentacles
of the medusa-stage of Syncoryne have the ordinary arrangement of
stinging cells at intervals along the length, i.c. without any suggestion
of the massing seen in the tentacles of the Hydroid stage.

Viewed with good illumination, the unburst stinging-cells can
readily be observed in the terminal knobs as more or less lenticular
bodies, and by judicious squeezing of a living polypite, some of these
may be pressed out, and a number will be certain to project the long
whip-like process which serves as the active agency in conveying the
poisonous secretion of the cell into the organism against which it is
launched. |

The isolated undischarged nematocyst can be made out to be a
cell of unusual size, somewhat ovoid in shape, and in which the most
conspicuous content is a great clear cyst, highly refractive, and filled
with a clear fluid, lying wherein is a spirally coiled filament. The
cyst does not occupy the entire cavity of the parent cell, but leaves
a space, most marked towards the base, filled with dense protoplasm,
in which lies a well-defined nucleus. From the apex of the cell
projects a pointed process of the cell wall, named the “trigger ”
and which functions as such on contact with a suitable body
(prey). It appears to stimulate the cell to a contraction, resulting in
the violent expulsion of the sting thread. The thread thus expelled
is not solid but is hollow, and in reality a tenuous prolongation of the
upper end of the cyst. It arose as an ingrowth or invagination of
the summit of the cyst, and when projected went through an instan-
taneous process of evagination, 7.c. was turned inside out as the

36 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

finger of a glove can be turned, and if we remember that the content
of the cyst 1s a watery fluid under considerable tension, one can
easily understand that if this tension be greatly and suddenly
intensified by pressure upon the walls from without, an instantaneous
throwing out of the ingrown hollow thread must ensue.

A working model of such a cyst can be made of india-rubber
tissue, if fashioned in the form of a hollow bulb with the apex dwin-
dling down into a finger-shaped hollow appendix. If this hollow
model were partly filled with water and the filiform apex thrust
inwards (invaginated), then by squeezing the bulbous part, the
pressure of the contained water would force outwards the invaginated
finger—the equivalent of the hollow filiform thread of the nematocyst.
In the Corynide, the base of the thread is stout and furnished with
barbs.

The stem of the tentacle is formed as in Obelia of a solid
core of vacuolated stiff-walled cells of endodermal origin, that act as
a supporting axis. The ectoderm is thin, but furnishes very delicate
yet powerful muscle elements that control the elongation and re-
traction of the tentacles.

The mouth that is fed by these ministering and food-capturing
tentacles is small and terminal and difficult to distinguish, appearing
as a mere opening, at the anterior end of the polypite. The large
cavity of the polypite is where digestion takes place, the endoderm
cells of this region secreting a fluid which rapidly dissolves the tissues
of the prey.. Thence this nutrient fluid is passed along the hollow
coenosare to aid in the sustenance of the general body of the colony.

Reproduction.— Normally Syncoryne produces buds at various
and indefinite points scattered over the body of the polypite and
between the tentacles. These buds at first consist of a layer of
ectoderm covering a hollow button-like outgrowth of endoderm. Next
this endoderm projects four hollow radial processes which ultimately
become the four radial canals of the Medusa, into which the bud
eventually develops. At the same time a median outgrowth of
hollow endoderm, the future manubrium, grows down between the
four radial bands.

With growth the form becomes distinctly bell-shaped, the
four marginal tentacles appear associated with the four radial canals,
and a pigmented eyespot—ocellus—develops at the base of each
tentacle. Thus, little by little, the bud changes into a well marked
medusiform organism connected to the polypite by a narrow neck.
At this stage the medusiform bud is usually nearly as large as the
polypite itself. At length, it begins to pulsate, to long for separate
and free existence, and its efforts quickly effect severance from the
mother polypite,

Journ. of Mar. Zoo! & Microscopy. Wrote Aes IN

JAS HOMNELL, DEL. AD NAT.

CORYNE AND SYNCORYNE,

Fig.
Fig. 2

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

EXPLANATION OF PLATE IV.
The Corynide.

Syncoryne eximia, natural size of colony.

Normal hydranth of same showing developing medusiform
persons, mb! to mb®, in various stages, disposed irregularly.
between the capitate tentacles; mb® is the oldest and is
all but ready to be set free; pr. perisarc. X 30.

A free medusa (Sarsia) of Syncoryne, fully mature (probably
two months after being set free); m. manubrium, within
whose walls sperm has been developed, this imdividual
being a male; ic. a captured Copepod being digested
within the cavity of the manubrium ; r.c. radial canals ;
e.¢. circular canal; es. eye-spot or ocellus; 0. mouth;
v. velum ; t. tentacle. x 44.

Hydranth showing abnormal medusiform person, a.m.b.,
wherein, while the bell is fully developed, the tentacles
are aborted, and the manubrium functions solely as a
reproductive organ (in this case, a spermarium). The
bell remains permanently attached and the reproductive
products are ripened in situ; d.m.b. developing medusa-
bud ; ¢.s. eye-spot ; p. perisarc ; ¢. coenosarc ; 0. mouth.

A row of axial endoderm cells from a tentacle of Syncoryne.
x 180.

Colony of Coryne vaginata, nat. size. (The annulations
of the stem are not visible to the naked eye, in living
specimens).

Hydranth from a male colony of same species; mg. male
reproductive capsule, representing a degenerate medusa.

Hydranth from a female colony; fg. female capsules filled
with ova; ¢. tentacles; . stinging threads of nematocysts ;
0. mouth; ¢. tiny membraneous cup at the base of the
hydranth. X 30.

Nematocysts from tentacle of Coryne vaginata, x 600.

A & C, two burst nematocysts, showing barbs (0.) in different
positions ; th. the evaginated threads; B, an unburst
nematocyst, showing the trigger (¢), and the coiled thread
lying within the cyst (c); n. nucleus.

EXPLANATION OF PLATE V.
Figs 1 to 8, Curripedia.

Fig. 1. Sacculina carcini (Thomps.) seen in plan, showing by
means of the dotted outline of the crab upon which it is
parasitic, the manner in which the root-tubules ramify
through the host’s body. Natural size.

b.s. body-sac of Sacculina ; cl. cloacal opening ; b.m. basilar
membrane ; a7. the roots which ramify around the
intestine and the associated organs; h.r. hepatic roots
ramifying among the ceca of the liver; br.c. branchial
cavity of the host.

Fig. 2. Lateral view of same.

Fig, 3. _ Life appearance of Rock Barnacle (B. balanoides), enlarged.

Fig. 4. The same seen from above. a, b, ¢, d, e, and f, the six
plates making up the circular mantle “ rampart.”

Fig. 5. Dissection (partly diagrammatic) of B. balanoides, the right
half of the mantle-wall removed ; the “ liver,’ cement
gland, and branchiz are omitted; the alimentary canal
is depicted black ; for clearness, the male organs are not
lettered, but reference to Fig. 7 will indicate their parts.

Fig. 6. A Ship-Barnacle (Zepas) having the right side of the mantle
removed. The penis should not be apparent, as it lies
normally folded up between the cirri.

Fig. 7. Dissection of same, on the lines of Fig. 5.

Fig. 8. External appearance of Lepas anatifera, natural size.

Lettering the same for all the figures:—qa@ remains of the
anterior antenne; an. anus; a.m. adductor muscle; ce. carina ;
c.f. caudal forks ; ¢.g. cement gland ; cr. cirriform feet ; ¢.s. calcareous
rampart-shell of mantle ; fa. filiform appendages of 1st pair of feet ;
h. liver; l. labrum; m’ retractor muscle of scutum: m’ retractor
muscle of tergum; m.c. mantle cavity; od. oviduct; or.c. buccal
eminence ; 0. mouth; ov. ovary; p. penis; pd. peduncle or stalk ;
s. scutum ; ¢. tergum; ts. testis; ud. vas deferens; v.s. seminal
vesicle.

oo

Figs A to D, Plumularia pumila.
Fig. A. Branches of P. pumila, slightly larger than life. g. gonangia;

s. creeping stem or stolon connecting the various bundles.

Fig. B. Portion of branch, highly magnified, hydranths or polypites
in various stages of extension; h. body of the hydranth ;
ht. hydrotheca lodging hydranth ; g.c. gastric cavity of
hydranth ; ¢. ccenosare ; ¢.c. cavity of the ccenosarcal tube ;
pr. perisarc ; Z. tissue connecting hydranth with lateral
and internal surface of hydrotheca; ec. ectoderm; en.
endoderm; d.he. developing hydrocaulus or stem; dh.
developing hydranth.

Fig. C. Female gonangium; bl. blastostyle; ¢. swollen hollow apex
of blastostyle nearly ready to force its way through the
mouth of the gonangium ; ov. ova.

Fig. D. The same fully developed, showing the acrocyst containing
ova. (After Lindstrém),

Journ. of Mar. Zool. & Microscopy.

FS,

S

DEL. AD NAT.

Jas HORNELL,

SERTULARIA AND CIRRIPEDE MORPHOLOGY,

QR
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MICROSCOPICAL STUDIES. OL

Once freed, it begins a long, free-swimming existence and rapidly
increases in size till it reaches fully 4-im. in length. The manubrium
in this species attains enormous proportions—sometimes, when fully
extended, quite thrice the length of the bell. In this and allied forms
(ue. among all the Gymnoblastic Hydroids), the genital organs
appear in the walls of the manubrium of the medusa. The sexes
are separate, and the embryos that are produced settle down and
develop hydroid stocks or colonies.

I have said that the foregoing is the normal course of repro-
duction—but certain species, and among others that under present
consideration, S. exvmia, have an alternative mode. This however
is practised only at the end of the breeding season (April) when the
reproductive buds, in place of developing into free medusz (Sarsza,
as this form of medusa was called before it was recognised as one
stage in the life-cycle of this Hydroid), remain permanently attached
to the hydroid stock. In form they have the same bell shape
as the true medusa-buds, but they seldom produce tentacles
(stunted when produced), and the manubrium becomes enormously
swollen with the reproductive products. The lack of tentacles is to
be adduced to the fact that owing to the permanence of attachment
to the parent, all nutritive matter is obtained from that source, and
the manubrium has no call to act as a digestive organ, but simply
as a reproductive gland.

The next and final stage of degeneration is found in such forms
as constitute the genus Coryne, of which the lovely species C.
vaginata, grows luxuriantly in Jersey rock-pools and gullies—where
it forms clegant branched colonies that appear miniature shrubs,
crowded with delicately tinted pink florets. Both the main stem and
the branches are horny and closely annulated. In the details of the
anatomy of the polypites there is practical identity with those of
Syncoryne. In Coryne, however, the polypite is considerably larger,
but it is solely the divergence of the reproductive plan that entitles —
this species and its congeners to the dignity of a separate genus.

The colonies are again unisexual, some bearing only male
buds, while others bear female ones. These appear as numerous
rounded bodies clustered on the polypites between the bases of
the tentacles. ‘The male ones consist solely of masses of cells—
spermatoblasts—which produce spermatozoa ; while each of the female
buds becomes filled with 20 to 25 large ova. When the male
capsules burst, it is probable that the spermatozoa find their way
to the female organs, guided by some sense or attraction we know
not what, and pierce the membranous envelope, thereby gaining
admission to the ova. The latter, thus fertilized, by segmention form
tiny embryos, which issue forth as four-armed hydriform larve, that

38 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY,

crawl about like so many miniature Octopods. This free life is rapidly
run and then they settle down and become attached to rock or weed.
In this situation they rapidly reproduce, by continued budding, the
typical hydroid stock. Here, then, there is no trace whatever of
medusee, whether fully developed as free-swimming organisms, or
bereft of a free existence and tied for life to the mother polypite :
nought is left of the medusa-stage save the reproductive organs,
and as these are, among the Gymnoblastic Hydroids, situated in the
walls of the manubrium, we may homologize the sexual buds of
Coryne, with the manubria of such meduse.

As Obeliw may be taken as typical in every sense of the
Calyptoblastic Hydroidea, where the polypites are lodged in
cup-like expansions of the horny perisarc, the medusz usually
provided with otocysts (rarely with eye-spots), and the genital
glands developed upon the radial canals, so Coryne and Syncoryne
may be taken as the types of that other great division of the
Hydroidea, known as the Gymnoblastic—characterised by the
polypites being naked or athecate, the medusze, when produced,
provided with eye-spots (ocelli}) and never with otocysts, and
with the genital glands lodged in the walls of the manubrium, and
not in the course of the radial canals.

To the student of the smaller forms of marine life, the stems
of the Corynidee offer endless material for research, so abundantly
are they clothed, at times, with a fluffy growth that under the
mucroscope is revealed to consist of multiform Diatoms, lovely in the
delicacy of their glassy sculpturing and in the rich hues of the living
matter within them ; cf more minute Infuscrians, the cups, and bells
and tassels of those that live their lives attached, and still smaller
forms, cilia-rowed and free-swimming, that speed and rotate and take
eccentric course among the miniature undergrowth upon the crowded
stems; here and there too, can be spied a slow-crawling Foraminifer
whose porcellain-white shell gleams brilliantly, while from innu-
merable pores stretch living threads along which hurry, this way
and that, the tiny particles that are engaged in the life-building
of the tiny creature; the stont bobbing heads of that curious Polyzoon,
Pedicellina, are frequent, curtseying and bowing to one another,
with old world homage; to the keen-eyed, interesting forms of
Rotifers, so rare in the sea, may occasionally reveal themselves spin-
ning erratic course through the water or climbing about with jerk
and double among the rich growth of the tiny alge that form never-
theless the giants of this tiny microscopic forest.

None of these can be accounted parasites; they occasion no
harm to the host and simply live together—a crowd of commensals,

Pad
' 7, &

MICROSCOPICAL STUDIES. 39

_ A true parasite, however, sometimes afflicts colonies of Syncoryne,
as one of the curious Pycnogonide (sea-spiders) makes use of the
developing buds as incubatory sacs, wherein their larvee may develop.
How the ova are deposited in the Zoophyte is unknown—but as the
larvee are only found in young buds, it is likely that these are selected
as being without the hard perisare which is present at other parts
of the colony and which would render an incision difficult. Probably
the Pycnogonid breaks a hole in the crown of the bud and introduces
therein the ova. The effect is to arrest normal growth and to convert
the bud into a “gall”—wherein the larve live, nourished by the
nutrient fluid of the ccenosarcal tube, a branch of which penetrates
the bud. In due season the larvee burst from the gall and become
free.

Stupy XIX.—On SERTULARIA PUMILA.

Just as Obelia geniculata forms miniature forests on the broad
leaves of Laminaria (oar-weed) at a horizon seldom left bare except
at very low tides, so another species of the Hydroidea, Sertularia
pumila, in favourable situations, monopolizes the fronds of Fucus
at a zone some feet higher. Ellis, the worthy pioneer in our know-
ledge of these forms, named it the “Sea-oak Coralline,” an appropriate
name, and one suggestive of the strong, stunted and rather coarsely
denticulated appearance it assumes when removed from the water.
It seldom attains luxuriant growth ; most frequently it is barely
¢ of an inch in height and as it retains the same breadth from base
to apex and is hardly branched at all, it has an incomplete and
truncated appearance that does not make for gracefulness.

Occasionally, however, it grows to the height of an inch and a
quarter and is then beautified with several branches arranged
symmetrically in pairs.

In texture it is horny, owing to the perisare being strongly
chitinized. Examining a living branch in water under a low power
of the microscope, we forget its apparently coarse nature in the
loveliness of the expanded polypites. They are exquisite in their

_slenderness, and have a great power of protrusion. Equally long

and graceful are the hyaline tentacles, a living rosette that surrounds
in a single wreath the broad and button-shaped proboscis, whose
summit breaks into a large and mobile mouth. The cups (hydrothece)
that lodge these polyps are paired, one on either side of each segment
or internode in the stem. Somewhat tubular in form, each cup is,
at the lower end, pressed to the side of the stem internode, while
the upper extremity is free and bends outwards, so that each pair,
with their stem internode, form a V-shaped figure. The aperture

40 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

of each hydrotheca is somewhat narrowed and sculptured into points
—mucronate. The body of each polypite is nearly cylindrical
(compare with the cup-shaped body in Obelia) and has a special
bundle of retractile fibres inserted on the outer surface of the body,
some little way beneath the tentacles on the side turned towards
the axis of the stem. Thence they pass inwards and slightly down-
wards to become attached to the wall of the hydrotheca where fused
with the stem perisare. By contraction these fibres energetically
assist in the retraction of the polypite.

The body wall of each polypite, as also the ccenosarcal tube,
consists: essentially of a simple ectoderm layer separated from a
ciliated endoderm by a delicate supporting lamina.

The endoderm is usually separated by a space from the investing
perisare, except at the base of each hydranth and at the points where
growth is taking place.

The perisare is a secretion of the ectoderm and thus, where a
polyp bud or a new branch is originating, the ectodermal cells are
of enormous size. As the perisarc is completed the ectodermal cells
dwindle and shrink away from it.

The special growth of the branch is as follows :—the perisarc
between the two terminal hydrothecee becomes absorbed and the
blind termination of the ccenosare pushes through ; next, this throws
out a hollow bud on either side. In these three buds, the ectoderm
is very thick and active and rapidly forms a layer of perisarc, the
lateral buds becoming hydranths, the median, an. internode of the
hydrocaulus or stem.

The branches bear in their number a direct ratio to the
abundance of nutriment and other favourable life conditions; when
present, they have always one definite point of origin, and that is,
from the hydrocaulus just beneath the base of a hydrotheca. There
the perisare is absorbed and the ccenosare pushes out a tiny bud
which in further development repeats the process of apical growth
already described.

‘The tentacles have the same structure as in Obelia.

Reproduction.—In the breeding season numerous large ovate
sacs—the gonothece or gonangia appear here and there on the
main stems and branches. Their origin is similar to that of the
branches, by absorption of the perisare and thrusting out of a hollow
bud of ccenosare. These sacs produce in due course the reproductive
elements.

The sexes are separate and in separate colonies. Male gonangia
can usually be distinguished from female by their shape —the
former being regularly oval, the latter irregularly ovate.

MICROSCOPICAL STUDIES. Al

The prolongation of the coenosare into the gonangium is termed
the blastostyle. This fills but a small space and is little more than
a narrow column in the centre. In its walls are developed sperm or
ova as the case may be, and thus while it (the blastostyle) represents
really the medusiform person, the medusa itself is entirely abortive,
the reproductive organs alone being retained.

Fertilization takes place as in Coryne, and then a peculiar
occurrence takes place. The apex of the blastostyle gradually
expands into a hollow globe with gelatinous walls, which pushes its
way through the aperture of the gonangium to hang from the
mouth as a miniature bladder. Into this pouch, the acrocyst or
marsupium—the fertilized ova are passed and therein undergo
segmentation. They pass out as planule—which after a short free
life settle down, and by the usual process of growth and budding
complete the life-cycle by developing new colonial organisms.

Sertularia obviously belongs to the Calyptoblastic or Thecate
Hydroids, the polypites beimg lodged in thece, and it is significant
to note that 1b occupies the same relative position to Obelia in regard
to mede of reproduction, as Coryne occupies to Syncoryne among
Gymnoblastic Hydroids. In both Sertularia and Coryne there is
suppression of a medusiform stage. In Obelia and Syncoryne, free
sexual medusze are produced—a striking parallel.

From the geological standpoint, Sertularia is of considerable
interest, as it seems to offer the most probable relationship to the
curious Graptolites, those most abundant fossils of Silurian rocks ;
the short sessile hydrothecee of Sertularia, giving its stems a serrate
appearance, offering great suggestive resemblance to the denticulated
margins of the fossils in question.

Stupy XX.—THE CIRRIPEDIA.

Than the Barnacles or Cirripedes (“ cirrus-footed ”), few marine
animals are more familiar to dwellers by the sea; the sessile forms
exist everywhere upon the littoral; the stalked are known world-wide
as Ship-Barnacles, adhering to the bottoms of ships or to wave-tossed
timbers.

The greatest diversity of form is found in this order, from the
great stalked forms and the mollusc-like Rock-Barnacles, encased in
shelly walls, that cover in multitudes all high-tide rocks; from
parasitic species, more or less degraded, yet endowed with optional
freedom, down to curious bag-shaped parasites whose lives are bound
up absolutely with that of the host, and through whose vitals their
ramifying roots bend and twist. All agree, however, in larval history,

A? JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

passing successively through those special phases known as the
Nauplius and Cypris stages.

The most primitive type is that of the stalked or pedunculate
forms, and of these, Lepas is the most typical genus. The young
of this, emerge from the egg as very tiny Nauplii—minute larve
furnished with but three pairs of appendages, all used at first as
swimming organs (Fig. 19, Pi. vii, Vol. I). The two anterior pairs
represent the two pairs of antenne while the third pair ultimately
become the mandibles in the adult. The first pair of these limbs
are simple; the others are biramose (two-branched). One eye,
unpaired and median—the Nauplius-eye—is developed, and the body
is protected by a dorsal shield-shaped fold of integument, the broad
anterior margin produced on either side into a fronto-lateral horn.
Mouth, alimentary canal and anus are present, and the creature feeds
eagerly. Frequent moults Cecdyses) take place, and with each such
change, important additions are made to the number of the organs
and appendages; a series of segments are produced posteriorly,
destined to form the adult thorax; limbs sprout from these, and a
compound eye appears on either side of the Nauplius-eye.

At last a moult occurs when a larva quite different to any of the
preceding Nauplinus gradations issues from the old skin. In this
new phase the larva has the general form of an Ostracod—hence is
called the Cypris-stage—being provided with a bivalve shell,
composed of two oval convex valves, open along the ventral edge,
within which the entire body and its limbs can be retracted. All
three regions of the typical crustacean body, head, thorax and
abdomen, can be traced (Fig. 24, Pl. I). The thorax has six strong
limbs, while the abdomen, short and insignificant, possesses but a
single pair. Of the appendages of the head, the second pair repre-
senting the posterior antennee—have disappeared, while the third
pair are reduced from their former important biramose character to
small mouth organs—the mandibles. Tiny swellings, that ultimately
become the first and second maxille, are also to be seen. The first
antenne on the other hand, increase in size and become provided
with a bell-like sucker on the penultimate joint, and on this sucker
opens a cement-producing gland. The larva now ceases feeding,
much food reserve appearing as oil-globules, especially at the anterior
end of the body.

The time has now arrived for the assumption of adult life, and
this is set about by the larva attaching itself—preferably to some
floating body—by means of the suckers on the first antenne. Next
the cement glands pour out their secretion at the same spot, and
embed the anterior end of the body firmly. The head region elongates,
becomes a mere stalk, the bivalve cypris-shells fall away, a chitinous

MICROSCOPICAL STUDIES. 43

fold of the integument grows around the trunk, and in the substance
of this mantle or pallial fold, five protective calcareous plates are
formed, one unpaired and the others paired. Early adult form is
now attained.

When fully grown and sexually mature, Lepas has the external.
appearance shown in Fig. 8, Pl. 5. The anterior end of the head
has become a great wrinkled pedunele or stalk, terminated posteriorly
in a shelly pouch, the mantle, enveloping the main mass of the body
and open only along a slit on the ventral border. Of the calcareous
plates strengthening this mantle, the larger of the two pairs, situated
towards the insertion of the peduncle, are termed the seuta (s); the
other pair placed at the far end of the mantle sac, are the terga (t),
while the unpaired plate, the carina (c), is a long and narrow keel
and separates, on the dorsal aspect, the opposite plates of the terga
and the scuta.

Removing one side of the mantle, with its scutum and its tergum,
the actual body of the Barnacle is exposed—an cbscurely segmented
fleshy mass, bearing conspicuous tendril-like limbs. What corresponds
with the typical Crustacean head lies before these latter, and is
divided into 3 regions; the anterior les without the mantle and is
the peduncle; the median is short and narrow and being attached —
to the mantle and connected along the inner surface with the peduncle,
forms an “isthmus” ; the posterior, the most important, is large and
fleshy, and bears the mouth and its organs.

Succeeding the posterior division of the head lies the partly
segmented limb-bearing thorax, and behind this again is found a very
small and rudimentary truncated abdomen terminating in two tiny
pointed processes. ‘Tiny though it be, the abdomen is of importance,
for upon the dorsal surface is the anus, and it as well gives origin
to an organ many times larger than itself; an organ long, stout,
cylindrical, annulated and setose, that functions as the male copulatory
organ, and may be termed the penis. In life this organ is bent down
between the thoracic limbs, as shown in Fig. 5 (p), and not as
in Figs. 6 and 7, where it is straightened for the purpose of
clearness in the drawing.

Of the appendages of the head, the anterior antenne persist in
a very minute and attenuated condition, at the anterior end of the
peduncle, where they lie embedded in the attaching cement ;
posterior antenne are absent, and the mouth parts are much reduced,
forming a small eminence surrounding the mouth. The parts com-
prise an upper lip or labrum with labial palps, two mandibles and
four maxillee, of which the hinder pair form a lower lip.

The thoracic appendages or feet, six pairs in number, are all
tendril-like, long, slender, many-jointed, and closely set with a double

44, JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

row of stiff hairs. Each is biramose, 1.e. composed of two branches,
which arise from a single stout basal joint, the protopodite.

Alimentary Canal.—The mouth opens into a short straight
cesophagus, leading into a capacious stomach, beset at the anterior
end with glandular diverticula (liver). Posteriorly the stomach
narrows gradually to merge into a long intestine, with anus opening
on the dorsal face of the truncated abdomen. Food is obtained by
the sweeping motion of the thoracic appendages, which by alternate
protrusion and retraction sweep inwards towards the mouth such
microscopical food as suffices.

The nervous system is limited to a paired cerebral ganglion
and a short ventral chain of 5 paired ganglia. Except a double pig-
ment-spot representing the eyes, no definite sense organs are known.

In the isthmus attaching the main body mass to the mantle, is
a strong transverse adductor muscle connecting the scuta of opposite
sides. By means of this, are controlled the opening and the closing of
the mantle cleft through which are protruded the cirriform feet.
Numerous other muscles are also found in the posterior head region,
chiefly concerned in controlling those movements of the body which
alternately elevate and depress the limbs and allow their sweeping
motion to perform at fullest advantage. In the walls of the peduncle
we also find strong muscles, having a longitudinal arrangement.

Reproduction.—Lepas is hermaphrodite, possessing both testes
and ovaries. The former consist of ramified arborescent whitish
tubules lymg along either side of the digestive canal and penetrating
even into the basal joints of the limbs. The product of these glands
is gathered into canals tributary to larger, which finally pour it into
two conspicuous milk-white seminal vesicles, whose vasa differentia
run separate almost to the base of the penis. At this point the two
unite and form a common ejaculatory duct passing through the penis.
The ramified ovaries, purplish in colour, lie within the posterior
portion of the peduncle, and the two oviducts (ov. Fig. 7) after
passing through the isthmus, open, one on either side of the head, at
the base of the first pair of thoracic feet—a forward position wholly
exceptional among Crustaceans where the usual position for the
female orifices is upon the first abdominal segment among the lower
forms (Copepods, &c.), while in the higher (Malacostraca), it 1s
constant to the antepenultimate thoracic segment.

The ova when extruded become cemented together into two
large purplish plate-shaped masses enfolding the main body region.
These plates are nearly always present, and on removing the mantle
are most conspicuous objects. ‘Two small simple folds of the mantle
integument—the ovigerous frena—arising close to the isthmus,
furnish attachment to these ova masses, and prevent them being

MICROSCOPICAL STUDIES. 45

washed away. It is interesting to note that among the sessile
Cirripedes, the Balanide, &c., these mantle folds are greatly
developed, and in some cases have their surface area increased by
further folding. Very probably their function under such con-
ditions is branchial, and we may be warranted in describing them as
branchie.

As in all other Cirripedes, no distinct blood system can be
traced in Lepas.

The second common Cirripede type in our seas, is the little
Acorn-shell, or Rock-barnacle (Balanus). In larval history it is
identical with Lepas, but in external adult form, it presents a
wonderful contrast. Fleshy stalk has entirely disappeared and the
pallial sac, which lodges the body proper, is therefore sessile. Much
modification of the shelly plates of the mantle has taken place, the
parts being so arranged as to form a shelly palisade, wherein six
distinct pieces are to be traced, roofed in by two pairs of plates, one
pair representing the terga of Zepas, the other and larger pair, the
scuta. When the tide flows over these tiny creatures, a slit-like
opening between these opercular plates is revealed, through which
sweep in and out, with elegant motion, tiny feather cirri, the thoracic
feet (Fig. 3). With the receding tide, life-functions are partly
suspended, the cirri are retracted, and the scuta and terga are shut
down tightly, so as to retain some moisture till the tide returns.
Quite an appreciable noise is made in the tightening of the valves
when in this quiescent condition, and the low crackling murmur
heard when walking over rocks thickly coated with Barnacles, is very
familiar to me. Apparently the vibration of a heavy footstep is
perceptible to them, and lest it betoken danger, they take the
precaution of tightening their opercular valves, and in so doing form
some tiny water-bubbles, which in breaking give out sufficient sound
to be very noticeable when joined in by thousands of individuals.

In the anatomy of the body, apart from the mantle, there is
practical similarity to that of Lepas; the main differences are that
the cement gland is greatly increased, the ovigerous frena developed
into two large folds functioning probably as branchie, while two special
and strong muscles are developed at either end of the rampart-like shell
to control the closing of the scuta and terga (m! and m?, Fig. 5).
Yet another and more important difference is seen in the ventral
nerve ganglia being concentrated into a single large ganglionic mass.

The third type of Cirripede which I select, is as utterly unlike
either of the preceding as it is possible to conceive, appearing simply
as an oval bag without calcareous plates or even sculpturing, attached
to the under surface of the abdomen of crabs. From this external
sac penetrate into the interior of the host long branching tubuli,

A6 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

twining around the viscera and insinuated among the ceca of the
liver. Nutrient matter is there obtained and is thence conveyed to
the sac-like body. The latter contains neither alimentary canal,
limbs, or other appendages. Shortly stated, its structure is that of
a double walled sac, the inner of which contains large lobate ovaries,
closely united, 2 testes, 2 cement glands, and a single nerve ganglion.
The ovaries and the cement glands open by small apertures into a
large space, the brood cavity, cccupying the space between the
outer and the inner sacs. Here the ova undergo their early develop-
ment, and as Nawpli pass forth through a well-marked opening, the
cloaca (cl., Figs. 1 and 2, Pl. 5) possessed of a strong closing or
sphincter muscle. Externally the cloacal aperture is obvious as a
prominent papilla.

The young issue forth as fairly typical Nauplu, but differ from
those of Lepas and Balanus in being destitute of paired eyes, mouth,
and alimentary canal; a central cellular mass, the rudiment of the
ovaries, is conspicuous. The Cypris-stage, into which the larva
enters after its fourth moult, also resembles a normal Cirripede
Cypris-larva, but deviates also in the absence of alimentary canal and
paired eyes. To this point the larval history is that of an ordinary
Cirripede, and by this fact alone are we enabled to class Sacculina
definitely as a Cirripede Crustacean. Without such knowledge it
would be practically impossible to properly access its position in
nature’s scale.

After a short-free life, the Cypris-larva attaches itself by the
anterior antennee to the base of a seta or bristle upon the abdomen of a
young crab. In Jersey, I find Cancer paguwrus (the edible-crab) to
be the most frequently attacked; Pilumnus hirtellus is also com-
monly infested. On the other hand, I scarcely ever see Carcinus
monas attacked, and this is strange, as elsewhere this species is
credited with being the favourite haunt of the parasite.

Following upon attachment, the thoracic region and its limbs,
together with the abdomen, are severed and thrown away; the head
appendages wither and the cellular mass which alone remains of the
contents of the Cypris-valves, secretes a containing bag-shaped cuticle,
marking the formation of the Kentrogon larval stage ; the Cypris-
valves fall away; a second cuticle forms within the first cuticle of the
kentrogon sac; the anterior end is produced into a hollow arrow-like
process, which, passing forwards through the cavity of the anchoring
antenna, forces its way into the body of the crab-host. Through this
channel the contents of the sac pass, and then become surrounded by
a fresh cuticle. From this sac are thrown out branched roots rami-
fying in the course of time among the whole of the organs of the
crab,

MICROSCOPICAL STUDIES. AT

By these complicated phases Sacculina becomes primarily an
internal parasite, but as the size of the sac gradually enlarges, it
exercises so great pressure upon the integument of the abdomen of the
host as to cause such thinning as permits the sac to burst its way
through, and to appear as an external parasite. It is probable that
the internal stage is assumed to obviate the-danger of being thrown
off and thereby destroyed, on the occasions of its host’s moulting
during the early period of the attachment and before its roots have
had time to ramify extensively. It is significant of the paralizmg
effect exercised upon the growth of the crab, that once the sac has
become external, 7.¢. when it has reached adult life, with its roots
ramifying extrusively through the viscera, that moulting ceases,
the crab remaining stationary in size.

Occasionally I have found two Sacculine parasitic upon the
same crab. An mteresting feature in Sacculina, is that, although
hermaphrodite, complimental males exist, located usually around the
cloacal aperture of the sac. They have a Cypris-like appearance.

The three species of Cirripedes above described are thus all
connected by similarity in larval history (ontogeny). The diverse
adult forms are also linked together by a gradation of intermediate
types of great interest, that throw much light on the evolution of the
more changed. Thus the change from the stalked Lepas to the
sessile Balanus, can be understood by reference to Scalpellum, a
_ stalked genus where the peduncle is reduced and the number of the
calcareous plates of the mantle so augmented, some being intercalated
between the terga and scuta and the border of the peduncle, that if
the latter be lost and the carina and certain of the additional plates
join laterally and arrange themselves as a circular wall pushing away
the terga and scuta, we obtain the modification seen in Balanws—
a ring of plates with the opening closed, lid-lke, by the four plates
of the terga and scuta. ‘To the sac-like and limbless form of
Sacculina, the gap is largely bridged by our knowledge of such
genera as Alcippe and Cryptophialus, degenerate forms enveloped im
bag-shaped mantles, and provided with but three pairs of cirriform feet,
and which live parasitically in holes bored in shells. More degenerate
still is Proteolepas, a remarkable grub-like form living in the mantle
cavity of other Cirripedes; limbs are entirely absent and the
digestive tube is rudimentary.

Classification :—

Class -CRUSTAGEA. Sub-Class—Entomostraca.

Order.—CIRRIPEDIA.

Sub-Order I—Thoracica ; thorax always present, usually provided
with cirriform feet; mouth and alimentary canal
present,

48 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

Tribe —PEDUNCULATA ; stalked, six pairs thoracic limbs.
Families—Lepadide (stalks without calcareous plates or
hairs); and Pollicepedide (stalks with hairs or
plates).
Tribe I. —OprErcuLata ; sessile, limbs same as in Pedunculata.
Families —Balanide and Chthamalide (closely related,
both with a symmetric calcareous ring, each
branchia a single fold); Coronulidw (symmetric
ring of plates, each branchia doubly folded); Ver-
rucide (calcareous ring asymmetric).
Tribe JII—Axspomrnattia ; thorax reduced, bearing three pairs
of cirriform limbs.
Family I.—Alcippide, four pairs thoracic limbs, three
pairs being cirriform.
Family I1—Cryptophialide, three pairs only of thoracic
appendages—all cirriform.
Tribe [V.—Apopa ; no thoracic limbs, grub-like.
Family.—Proteolepadide.

Sub-Order I —Rhizocephala ; parasitic—body sac-like—without
mouth or alimentary canal; possessing root-like
processes that ramify in the viscera of the host.

One family only—Kentrogonide. 'The chief genera are
Peltogaster, parasitic on Hermit Crabs, and Sac-
culina, parasitic on Cancer, Carcinus, &e.

BOOK NOTICE.

“ Hlementary Physiology,” by Prof. J. R. Ainsworth Davis, 223 pp., 3 coloured
plates and 104 figures in text. (London; Blackie & Son, Ld., 1895). Price 2/-.

Practical zeal and discrimination are impressed so characteristically upon all
work undertaken by Prof. Ainsworth Davis, that one is inclined to accord this little
work a hearty welcome on the strength of the author’s credit alone. Detailed
examination confirms this view, and as an introductory text-book, we believe it to
be quite the best of its class. One cannot be too thankful to the author for the
stress with which he emphasizes the fact that Human Physiology is but a small
portion of Animal Physiology—too many students have, in the past, unconsciously
grown into the belief that the two are interchangeable terms. Prof. Davis takes
a very practical way of clinching his warning, by introducing an ably written
chapter upon the digestion of the ox, and the secretion of milk. This is as it ought
to be. In the chapter on practical work, the innovation is carried further still, for
the frog, rabbit, rat, sheep, and bullock are all pressed into service, and so induce
the requisite comprehension that all the vertebrates, including man, are upon
essentially the same plan.

The work is well and judiciously illustrated, and while invaluable to those
entering upon the study of this particular science, it ought also to be in the hands
of every intelligent person interested in the way his own body is built up. It will
also be invaluable to agricultural students, and specially to those engaged in
dairying.

A good index, and two sets of examination questions are appended.

Ghe Journal of fRarine Soolagy
and JPirvascopy :

A PLAINLY WORDED BIOLOGICAL MAGAZINE.

Vou. II. No. 7. SEPTEMBER, 1896.

REPORT ON THE SCHIZOPODA, CUMACEA, ISOPODA,
AND AMPHIPODA OF THE CHANNEL ISLANDS.

BY ALFRED 0. WALKER-F.LS. snp JAMES HORNELL.

INTRODUCTION.

HE Crustacea in the following list (excepting those printed in
heavy type) were collected by Monsieur E. Chevreux, the
well known French Carcinologist, who was so obliging as to

send me the list he had intended to publish in this Journal, by Dr.
C. H. Hurst, Mr. Hornell, and myself, as indicated below. Some of
the names also are taken from a collection of Jersey Crustacea in the
Free Public Museum at Bootle, Lancashire,' sent to me for identifi-
eation by Mr. Chadwick.

To make the list as complete as possible, Mr. J. Hornell, the
Director of the Jersey Biological Station, has added a number of
additional species and localities, which have either been recorded in
previous publications, or have been collected and identified by him or
by Mr. J. Sinel, and of which latter, the present is the first publication.
All these additional forms are distinguished by being printed in
heavy black type.

The following are the localities indicated by the letters and
figures attached to the names :—

Jersey (J).
1. Two miles off St. Helier’s Harbour, 9-10 fath. March 26, 1892;
AONE Won Orlalelals

2. Near the Red Buoy at the harbour entrance, 4 faths. gravel,
clinkers with Sabella tubes, &c. ; same date and collectors.

. Shore near St. Helier’s ; A.O.W. & C.H.H. March 27 and 28.

. Shore Portelet Bay. March 30. A.O.W. & C.H.H.

. Shore, Grande Azette, low spring tide; March 31, A.O.W. and
J. Hornell.
1 These were collected by Mr. J. Sinel in former years.—ED.

Or > OO

50 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

6. 4 miles S.E. of harbour, 10-12 fath., stony and rocky ground,
April 1; A.O.W. & C.H.H.

7. Shore below Grand Hotel, half tide ; April 2, A.O.W.

8. Collections from Jas. Hornell, July, 1892, &e.

9. Half-tide ponds among the reefs in St. Clement’s Bay.

10. Between tide-marks, 8. coast Jersey—chiefly from low-tide zone.

11. Tow-netted off S. coast Jersey.

Ch.—-Collected and named by Monsieur H. Chevreux from low tide on
Gréve d’Azette, 1895.

Bo. Mus.—Collection from Bootle Museum, 1895.

Guernsey (G).

1. Off St. Peter’s Port ; 7 fath., gravel, clinkers and shells. April 4,
1892, A.O.W.

2. Between the Castle and St. Martin’s, 10-15 faths.; April 5,
A.O.W.

3. Off St. Martin’s, 25 fath., April 5, A.O.W.

4. Between tide-marks, chiefly low-tide.

S.B.—Indicates records from the Channel Islands in Spence
Bate & Westwood’s “ History of the Br. Sessile-eyed Crustacea,”
London 1863 to 1868.

R.K.—Species and localities recorded by Prof. R. Kehler in
“ Recherches sur la Faune Marine des Iles Anglo-Normandes,”
Nancy, 1885, which are not overlapped by other records.

* A prefixed asterisk indicates such species of Isopods and
Amphipods as are named in the last cited work.

S. & H.—Collected or identified by J. Sinel and Jas. Hornell.

A.O.W.

SCHIZOPODA.

Macromysis flecuosus (Miller). J 11, common (S. & H.).-
“e neglectis (Sars). Salat (S. & H.).
ws inermis (Rathke). J 1, also from Guernsey by Canon
A. M. Norman (‘“ Ann. & Mag. Nat. Hist.,” Series 5,
No. xix.)
Macropsis Slabberi, van Beneden. Bo. Mus.
Schistomysis Helleri (Sars). J 11 (8. & H.).
Gastrosaccus spinifer (Goés). Bo. Mus.
Anchialus agilis, G. O. Sars. G1, G 2.
Cynthilia (Siriella) crassipes (G. O. Sars). G 2, also recorded by
Norman, from Jersey Joc. cit.
Cynthilia armata (M. Edw). Jersey (Norman, Joc. cit.)

CUMACBA.

Iphinoé trispinosa (Goodsir). J 1, J 2.
Nannastacus unguiculatus, Bate. G2.
Pseudocuma longicornis (Bate). J1, J 2.
Diastylis spinosa, Norman. G 1.

ISOPODA.
*Tanais uittatus (Rathke). J 10, G 4 (S. & Fey.

ISOPODA OF CHANNEL ISLANDS. 51

*Leptochelia Savignyi (Kréyer),—L. Edwardsi (Kroyer). G4(S.B.);
310 (8.& H.); Sark (R.K.)
*Paratanais Bater, Sars,—P. forcipatus (Lillj.). Bo. Mus.; Guernsey
(SS) e UO (Secaisty) se Sadie Cal@)
Apseudes Latreillei (M. Edw.). J 2, G1.
*Apseudes talpa (Mont.). off Guernsey (8.B.); J 10 (S. & H.).
Anthura gracilis (Mont.). With Corophium and Obisium in rock
crevices, Jersey (8. & H.).
*Paranthura nigropunctata (lucas)—P. costana, Bate & West. J9
(S.& H.); off Jersey (S.B.); J12& G4 (R.K,).
*Gnathia maxillaris (Montagu). Bo. Mus.; common in all the
islands, often commensal with sponges, &c., and also free, in
the tow-net (S. & H.).
*Anilocra asilus (Linn),—A. mediterranea, Leach. Herm (S.B.) ;
common as parasites, male and female together, upon the
head of Wrasse (Labride) (S. & H.).
Aega rosacea (Risso),—A. bicwrinata, Leach. Two specimens on a
Squatina angelus, Jersey (S. & H.).
*Cirolana Cranchii, Leach. Off coast of Jersey (R.K.).
Hurydice spinigera, Hansen. Probably identical with #. truncata,
Norman. bo. Mus.
Eurydice achatus (Slabber),—H. pulchra, Leach. Common Jersey
and Guernsey (8S. & H.).
*Conilera cylindracea (Mont.). Bo. Mus. ; Guernsey (8.B.) ; Jersey
(Sy ce lale))s
*Sphaeroma serratum (Fabr.). J7; common under stones, Jersey
(S. & H.) & (R.K.).
*Sphaeroma curtum, Leach. The S, Prideauxzianum, Leach, of
Keebler’s list, is probably this species, as the two names are
now considered synonyms. J8; common (S. & H.).
Sphaeroma Hookeri, Leach. Guernsey (8.B.).
Campecopea hirsuta (Mont.). Common in the dry Fuci at high-
water mark in all the islands (S. & H.).
*Dynamene rubra (Mont.),—D. viridis, Leach. J3,J8; common
(Sse a)
*Dynamene Montagui, Leach. In empty Balani shells (R.K.).
*@ymodoce truncata (Mont.). Bo. Mus.; J 10 (S. & H.). |
*Noesa bidentata (Adams). Vazon Bay, Guernsey (S.B.); in empty
Balani shells, Jersey (R.K. and S. & H.).
*Tdotea marina (Linn.), L. tricuspidata, Desm. and I. pelagica,
Leach. J 4; all islands, among alge, and also in tow-net at
night (S. & H.).
*Idotea linearis (Pennant). Guernsey (8.B.); J 10 & 11 (S. & H.).
*/dotea emarginata (Fabr.). ow-net only, Jersey (R.K.),
Zenobiana prismatica, Risso. Bo. Mus.
*Stenosoma acuminata (\.each). A single spezimen, St. Aubin’s (R.K).
*Stenosoma /ancifer (Seach), =S. appendiculata (Risso).
Munna Kroyeri, Goodsir. J9 (3. & H.).
*Janira maculosa, Leach. J4; Common under stones, Jersey
(R.K.) and (8. & H.).
Jera albifrons, Leach. J7; Common (8. & H.).
*Jcera nordmanni (Rathke). J10(S. & H.); Sark (R.K.).
*Jceropsis brevicornis, Kcehler. (xouliot Caves, Sark (R.K.).
Asellus aquaticus (Linn.). Common in ponds and ditches (5. & H.).
*limnoria lignorum (Rathke). Common in piles and wooden staging

in the sea (8S. & H.).

2 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

lone thoracica (Mont.) A male and a female on a Callianassa,
Jersey (8S. & H.)
Gyge hippolytes (Kréyer.) Parasitic on Hippolyte (S. & H.).
Gyge galathew, Sp. Bate & West. Parasitic on Galathea squamifera
chiefly, Jersey and Guernsey (8. & H.); Herm (8.B.)
*Bopyrus squillarum, Latr. Parasitic upon Palemon serratus very
commonly at all the islands (S. & H.); 5.B. records it upon
. P. Leachii trom same localities.
Liriopsis pygmeea (Rathke). In dredge off Guernsey (S.B.).
*Ligia oceanica (Linn.) Bo. Mus.; Common among rocks near high
water mark, even invading houses at times (S. & H.).

Oniscus asellus (Linn.). Very common under decaying wood and

similar habitats (S. & H.).

Porcellio scaber (Latr.). Common, Jersey (S. & H.).

‘Armadillo vulgaris (Latr.). Common amid decaying wood, &c.
(S. & H.).

AMPHIPODA.

*Orchestia mediterranea, Costa. J3; Ch.; male specimens were 20
mm. long; common, J9 (S. & H.).

*Tahtrus locusta (Pallas). Bo. Mus.; Ch.; Very common towards
high-water, even invading houses at high spring tides

(S. & H.).

Hyale Nilssont (Rathke). J3, 7, Ch.

Lysianaz longicornis (Lucas). J5,8,G2;Ju(S. & H.).

Lysianax Coste (M.ldw.). G2.

Perrierella Audouiniana (Bate). Ch.

Orchomene Batei, Sars. J5.6; Ch.; rather rare, Jersey (S. & H.).

Nannonyx Goésit (Boeck). J 5.

Tryphosa Sarsit (Bonnier). J 5.

Lepidepecreum carinatum, Bate. G1.; Jersey (S. & H.).

Bathyporeia norvegica, Sars. Ch.

Bathyporeia pilosa, Lindstrom. Under this species I include B.
pelagica, Bate, and B. Robertsoni, Bate. G1; common in
certain spots on the Jersey coast, burrowing in sand
(Shey Jel),

Urothoé marinus, Bate. Bo. Mus.; Ch.

Urothoé brevicornis, Bate. G1, 2,3; J11 (8S. & H.).

Urothoé pulchella (Costa). Ch.

Phoxocephalus Fultoni (Scott). J6; G3.

Phoxocephalus pectinatus, Walker. (Ann. & Mag. of Nat. Hist.,
ser. 6. Vol. xvii. p. 343).—P. simplex, Calman, in Trans.
Royal Irish Academy, Ap., 1896, nec Sp. Bate ; see also
Ann. & Mag. of Nat. Hist., xviii. p. 156. The type specimens
from which the specific diagnosis was made were dredged
off St. Peter‘s Port, Guernsey, in 7 faths., Apr. 4, 1892.

Ampelisca Bi ea (Bate). Ch. ; dredged off Noirmont Point, Jersey
(8S. & H.

Ampelisca brevicornis (Costa),—A. lwvigata, Lillj. Bo. Mus. ; Ch. ;
taken in company with the preceding species in dredge
(S. & H). :

Anipelisca tenuicornis, Lilljeborg. G1, 2; Ch.

Ampelisca gibba, Sars. G1.

Amphilochus manudens, Bate. Bo. Mus.; J 9 (S. & H.).

Amphilochus melanops, Walker. (Rev. of Amphipoda of L. M.B.C.
District, Trans. L’pool Biol. Soc., 1x., 1895, p. 298, Pl. 18, 19).

AMPHIPODA OF CHANNEL ISLANDS. Do

Stenothoé monoculoides (Mont.). J3; G1; Ch.; J9(S.& H.).

Metopa borealis, Sars. G3.

Leucothoé spinicarpa (Abildgaard). i o SieGr2i cde On (Sac ele):

Leucothoé Lilljeborgii, Boeck. G3 ;

Monoculodes carinatus, Bate. J1, 2: oe

Perioculodes longimanus (Bate). J 1,2), 2:5 Ch.

Synchelidiuim haplocheles (Grube). J i 2; Ceuk, so) Olny,

Pontocrates norvegicus, Boeck. Ch.

Iphimedia obesa, Rathke. G 2.

Husirus longipes, Boeck. G3.

Apherusa Jurini (M. Edw.),=Pherusa fucicola, Leach. J 3, 8.

Apherusa cirrus eee pegs oe bicuspis, Bate. J5; Ch.

Apherusa bispinosa (Bate). J1, 2,6,8; G1, 2,3; Ch.-

Calliopius leviusculus (Kroyer). J 4,

Paratylus Swammerdamu (M. Edw.). J2, 4,6; Ch.

Paratylus vedlomensis (Bate), J1; G2, 3.

Dexamine spinosa (Mont.). J 2, 5,8; Ch.; Common (8. & H.).

Dexamine thea, Boeck. J8; Ch.

Triteta gibbosa (Bate). J3.

Amathilla homari (Fabr.),—A. subini (Leach). Bo. Mus. ; Jersey

(S. & H.).

Gammarus marinus, Leach. J5,6;G2;Ch.; Common (S. & H.).

Gammarus campylops, Leach. Ch.; Jersey (S. & H.).

Gammarus locusta (Linn.). G2; Ch.; Jersey (S. & H.).

Gammarus Berilloni, Catta. Valley des Vaux and a ditch near St.
Brelade’s Bay, Jersey (Ch.). Hitherto this species has been
met with only in the Western Pyrenees, and hence its
presence in Jersey is an interesting and difficult problem.
For a valuable account of this species, together with figures
of its distinctive characters, see M. Ed. Chevreux’s paper
“Sur le Gammarus Berilloni, Catta,” in Bulletin de la
Soc. Zool. de France, tome XXI. p. 29.

Gammarus pulex (de Geer). Common in ditches and fresh water
streams in Jersey and Sark (Ch.); Jersey and Guernsey
(Sii& En):

Melita palmata (Mont.). J4,5; Ch.

Melita obtusata (Mont.) J2; Ch.; Jersey (S. & H.).

Melita gladiosa, Bate. G2; low-tide pool, Bordeaux Harbour,
Guernsey (S. & H.).

Mera grossimana (Mont.). J5; G1; Ch.; J10, very common
S. & H.

Mera Othonis (M. Hidwwa)sy Gele2i:

Mera semiserrata (Bate). G2 ce
The last two species I ’ consider to be identical, the latter
being the immature form.

Mera Batei, Norman. Gl, 2.

Megaluropus agilis, Norman. Gl.

Cheirocratus Sundevalli (Rathke). GI, 2; Ch.

Cheirocratus assimilis (Lilljeborg). G2, By

Gammarella brevicaudata (M. Edw.). Probably the G. longicornis
of Kehler; see Stebbing on “Challenger” Amphipoda, p.
566. J 2, 5, 7.

Microdeutopus damnoniensis (Bate). J3; G1; Ch.

Microdeutopus gryllotalpa, Costa. Ch.

Microdeutopus (Stimpsonella) chelifera (Bate). Ch.;J9 (8. & H.).

Microdeutopus versiculatus, Bate. Ch.

54 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

Aora gracilis, Bate. G 2, 5, 8.
Leptocheirus pilosus, Zaddach,—L. pectinatus (Norman). GI; Ch.
Monsieur Chevreux expresses doubt as to the identity of
the above species mainly on the ground that while
Norman describes the dactylus of the Ist gnathopods
as “much longer than the truncated extremity of the
propodos,” Zaddach, as translated by Spence Bate, says it
is “as long as the palm.” But it seems to me that
Zaddach considered the palm to be defined by the spine
which is situated a little below the ill-defined angle
formed by the truncated extremity and the posterior
margin, in which case both his definition and Norman’s
would be correct. it
Gammaropsis maculata (Johnston),—G. erythrophthalmus, Lillj.
J3,6; J9(S. & H.).
Megamphopus cornutus, Norman. J6; G3.
Microprotopus maculatus, Norman. J 2; Ch.
Photis longicaudatus (Bate). G1, a large male; dredged off La
Rocque, Jersey (S. & H.).
Amphithoé rubricata (Mont.); J5,7; G1; Ch.
Pleonexes gammaroides, Bate. J5; Ch.; J9 (8. & H.).
Sunamphithoé conformata, Bate. Bo. Mus. ; Ch.
Podocerus falcatus (Mont.). J1,4 (8. & H.).
Podocerus ocius, Bate. A male, J 8.
Erichthonius abditus (Templeton). J6; Gl.
Siphonecetes Colletti, Boeck. G1; Ch.; J11(S. & H.).
Corophium crassicorne, Bruzelius. G3; Ch.
Corophium grossipes (Linn.).. Bo. Mus.; Jersey (8S. & H.).
Colomastix pusilla, Grube,—Haeunguia sitilapes, Nordm. of Kcehler’s
list. Ch. Sark (R.K.)
Chelura terebrans, Philippi. J2; Common (8. & H.).
Dulichia porrecta, Bate. J6; G2.
Phtisica marina, Slabber. J4, 5; Ch.; on trawl rope, Jersey
(S. & H.).
Pariambus typicus (Kroyer). J 2.
Caprella acanthifera, Leach. The C. hystrix of Keehler’s list. Ch. ;
Common, Jersey (S. & H.).
Caprella acutifrons, Latreille. J.

The following additional species of Amphipods are communicated
by Mr. Jas. Hornell as collected and identified by him and Mr.

Sinel :—

Hoplonyx cicada (Kabr.),—Anonyx Holboli, Kroyer. Jersey.

Menigrates obtusifrons Boeck,—Anonyz plautus, Kréyer. Guernsey.

Pontocrates arenarius (Bate). Jersey.

Laphystius sturionis, Kréyer,—Darwinia compressa, Bate. Fairly
common. J 9.

Urothoé elegans (Bate). J9, 11; not common.

Iscea Montagui, M.EKdw. J9.

Iphimedia eblance, Bate? J. minuta, Sars. A single specimen
dredged otf Greve d’Azette. Oct., 1887.

Niphargus fontanus, Bate. Several specimens have been procured
from two wells on the outskirts of St. Helier, Jersey.
Letmatophilus tuberculatus, Bruzelius,—Cyrtophium Darwinii,

Bate. J9, common.

AMPHIPODA OF CHANNEL ISLANDS. 55

Hyperia galba (Mont.). Frequent in the genital pouches of Rhizo-
stoma.
Caprella linearis. Not uncommon. J 10.

As completing the list of the known Amphipod Fauna of the
Channel] Islands, Mr. Hornell adds the following six species which
have so far been recorded by Prof. Koehler alone (loc. cit.) :—

Orchestia littorea, Leach. Jersey, among alge.

Nicea Lubbockiana, Sp. Bate. Sark; Jersey, in company with
Styelopsis.

Stenothoé marina, Sp. Bate. Sark; Jersey, in same habitats as
Nicea.

Podocerus eavillatus, Rathke. Sark ; among Styelopsis, Jersey.

Lembos Websteri, Sp. Bate. Sark.

Protella phasma, Sp. Bate. Jersey.

‘THE USE OF FORMALIN AS A PRESERVATIVE
FLUID.

BY JAMES HORNELL.

For considerably more than a year I have had the action of
Formalin as a preservative fluid under constant observatiou, and, as
the results may prove useful to many readers, I will now summarise
them as much as possible.

The fluid as commercially sold is a 40°/, aqueous solution of
formaldehyde, but in use, for ease in reckoning percentages, this
must be considered as representing 100 °/,. Thus a5 °/, solution of
formalin is made up of 5 parts of the fluid as commercially sold,
diluted with 95 parts of water.

The chief biological value of formalin is essentially in the pre-
paration and preservation of specimens intended for dissection and
Museum purposes ; in microscopical technique—for reasons to be
mentioned later—its use is entirely secondary and limited.

Reviewing its application among the various phyla of animals we
find that :— .

SPONGES are most beautifully preserved by simple immersion,
without previous fixation. No contraction of even the most delicate
membrane is observable, and where there is natural transparency or
semi-opalescence, this is perfectly retained—Halisarca is a good
instance in point: spirit specimens become opaque and leathery-
looking ; formalin ones retain the characteristic jelly-like appearance,
with, however, a sensible stiffening that is just sufficient to become
valuable as diminishing the danger of injury to the specimen in
handling, &ec.

Hyprozoa. Hydroid stocks of the smaller sizes, being usually
required for microscopical examination, mounted in balsam, are best
preserved in the ordinary way by fixing and subsequent grading into
spirit ; this, because I find that the staining of formalin-preserved
specimens is inferior to that of well fixed spirit ones, as differention
is comparatively poor in the former case. For Meduse, great and
small, and for many Siphonophores, formalin finds one of its most
valuable applications. For instance, the large Meduse, Avwrelia,
Chrysaora, and Rhizostoma are preserved perfectly by simple
immersion in a 5°/, solution. No special care whatever is needed,
except that the animals should be perfectly healthy and active when
put in. They may remain in the original fluid indefinitely, though
in the case of animals containing a maximum of water in the tissues,
as do the large medusz, it is advantageous to change to a fresh
solution in the course of several days. The advisability for thig
depends very greatly upon the relative volume of the fluid contained
in the receptacle as compared with the bulk of the animals immersed

THE VALUE OF FORMALIN. 57

therein. The small medusxe, Sarsia, &e., are also a great success
when treated in the same way. Here, where the objects are of great
delicacy, I wish to emphasize the importance of making up the
Formalin solution with sea-water. The observance of this precaution
in some cases is absolutely necessary. With large and stout animals, as
fish, molluscs and the like, a fresh water solution is, however, per-
fectly admissible. |

ACTINOZOA preserve well also, but though the new treatment
has its advantages in transparency, I hesitate to say that it is better
for museum purposes than well prepared spirit specimens, as alcohol
imparts a very useful stiffness to the tentacles that is somewhat
lacking in the formalin ones. Much depends upon the dangers of
transit; thus where specimens can be prepared on the spot and
deposited on the museum shelves without a railway journey, then I
would recommend the formalin preparation made with a 6 °/, or 7°/,
solution, but if this cannot be done on the spot, then spirit specimens
will probably stand a railway journey better. For dissection purposes,
formalin is, however, fully equal, and in some cases decidedly
superior.

ECHINODERMS. Here I incline to prefer spirit to formalin
though both are good.

VERMES. The same remark applies here as in the preceding case.
There is really little to choose between the two methods.

CRUSTACEA. For the smaller, sucn as Copepods, Amphipods,
&¢., formalin is very useful when the objects are not required to be
mounted to show internal anatomy. LHspecially good is it for those
doing tow-netting, &c., at a distance from a laboratory base, where
all facilities are at hand. In such cases all that is requisite is to kill
the organisms either by the application of an ordinary fixative or by
pouring in a little strong formalin to cause the animals to settle to
the bottom of the vessel, so allowing the superfluous water to be
poured off ; this done, all that remains is to bottle the remainder in a
strong solution—lI prefer an 8°/, strength—label and put away.

For the larger specimens it also does well if wsed strong ; if used
at all weak, there is a tendency for the carapace to rise, leaving an
unnatural space between the hinder edge, and the anterior edge of
the succeeding segment. I notice, too, that limbs tend to become
more brittle than in the case of spirit specimens, while the fluid
frequently becomes milky, due, I believe, to chemical action on the
lime set up by some acid product of the formalin solution. Hence
it is inadvisable to use this fluid for museum preparations when
much caleareous matter is present.

MOLLUSCA gives most excellent results by formalin, and are
Superior in appearance, and in dissection qualities, to spirit ones.
1 cannot award too high praise to formalin for use upon these
animals.

TUNICATA. The same praise applies equally here, especially in

58 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

regard to the compound forms, such as Botryllus, Aplidinm, and the
like, where spirit results are notably so unsatisfactory. Comparative
retention of transparency with little or no shrinkage takes place
among even the most delicate, especially if a sea-water solution be
used.

PISCES. Formalin is here again unmistakeably superior to
spirit, but as the former is somewhat inferior in penetrative power,
when its internal organs, viscera, brain, &c., are required for dis-
section, it is essential that these should be carefully exposed and
frequently moved during the first few days to ensure the fluid
having free access to the inner parts. When once stiffened, they
keep perfectly in a 4°/, or 5°/, solution, though even lower strengths
will ensure preservation. Such lower strengths are however not
advisable, for as the price of even a strong formalin solution is much
less than spirit, it would be folly to risk spoiling good specimens for
the sake of a few pence.

Sponges, medusx, molluscs, tunicates and fishes are the groups
where the value of formalin reaches a maximum.

CoLOUR. Some writers have stated that formalin preserves most
colours unimpaired, but such an assertion can arise only from an
insufficient experience of its action. Lengthy familiarity has con-
vinced me that its extractive action in this respect is very similar to
that of spirit, and that the only difference is one of degree and not of
kind. Given a prolonged soaking in formalin, a red sea-weed or an
orange sponge will as surely fade as if they were in spirit, though if
kept out of strong light, the change may be so gradual as not to be
very noticeable for some time; a weak solution, of course, takes
much longer to impair colour than a strong, and indeed if perfect
internal preservation be not an essential, the employment of a 2°/,
solution will not appreciably impair the colour for a_ fairly
considerable time.

Where not stated otherwise in the preceding notes, a Df,
solution is to be inferred as the requisite strength.

As indicating the comparative price of formalin as opposed to
spirit, | may mention that at present average prices, a 5°/, solution
should cost considerably less than half the price of spirit, and in this
connection it must further be borne in mind that in order to perfectly
preserve in spirit several changes are necessary—whereas in formalin,
except in rare cases, not even one change is needful—hence the cost
of a formalin solution ranges, in reality, from one quarter to one
third of that of spirit.

——

ON SURFACE TENSION AS AN AID TO LOCOMOTION
AMONG MARINE ANIMALS.

BY JAMES HORNELL

Tt has long been known that certain species of nudibranch
molluscs can crawl in an inverted position on the surface of water,
taking advantage of that peculiarity residing in the surface film
known as surface-tension, but as I doubt if the extended range of
this habit is generally known, I venture to enumerate several
instances that have come under my personal observation ; some of
these have probably not been previously recorded.

The opisthobranch’ molluscs utilize surface tension the most
commonly. No species that I have watched fails to practise the
habit. Holis papillosa, Doris tuberculata, D. pilosa, Elysia viridis,
Pleurobranchus membranaceus, and P. plumula, continually do it,
and small individuals of Ap/ysia punctata at times adopt it. Size
appears to have little controlling effect,as large Doris, 5 inches long
and 3 inches broad, progress thus as easily and as rapidly as the tiny
Hlysia. Pleurobranchus plumiula is, however, the most persistent in -
the habit, sometimes passing hours together moving or at rest in the
inverted position at the surface. Molis comes next in point of fre-
quency in similar habits.

The little Cowry, Cyprea europed, is another and even more
interesting instance. In confinement, in a tank, it frequently crawls
inverted along the surface of the water, and occasionally may be seen
to form a little disc of mucus from which it lowers itself gently by a
mucous thread till it hangs in mid-water, dangling in the fashion of
aspider at the end of its silken cord. The cowry’s disc of mucus
thus functions as a float, supported not by any inherent lightness ag
is cork or wood, but by the aid given by the tension of the surface
film being sufficiently great to prevent the mucous mass from breaking

through.
This habit of the cowry is to be correlated to that more familiar

and natural one so readily verified by any observer who visits the
low-tide caves and gullies where, among sponges and ascidians, this
animal loves so to live. Here, when the tide recedes, cowries more
or less enveloped in their bright coloured mantle lobes, are often seen
passively hanging suspended from the gully’s roof, or from points
and jutting ledges by a stout mucous thread.

It is noteworthy that Holis occasionally suspends itself from the
surface of water ina similar manner to the cowry, that is by a mucous
thread pendant from a float of the same nature. Several times I have
noticed this to occur:when WHolis has been crawling inverted along

the surface. The length of the mucous cord was often as much as four

and five inches.
Passing to another group, we find that many of the smaller

60 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

crustaceans profit largely under natural conditions from the flotation
support afforded by the surface film. MNebalia especially utilizes it,
and indeed seems to require to exert a special effort in order to
break through the film when wishful to descend.. The Amphipod
Mera (various species) is another similar instance out of several
other genera of Amphipods. Indeed there are quite a number of
small crustaceans which may be occasionally seen floating on the
surface by this means. Conspicuous among these others are the
Cypris or pupal larve of the Barnacle (Salanus) and the fine Ostracod,
Asterope marie. To the former this habit is a very valuable one, as
it enables them to be lodged by the receding tide on the higher rocks
of the shore, just the situation suitable to their requirements ; the
presence of numerous oil-globules in these larva, is of much interest
in this connection, and must be of the utmost use to the animals in
bringing and keeping them within the influence of surface tension.
The nauplii of this creature, though much smaller, are scarcely ever
seen on the surface film, as they keep ata lower level ; it is obvious that
‘were they to rise into the surface film they would experience great
danger of being cast ashore, a fatal accident for them but just the
contingency required by the Cypris-larve.

While in Nebalia, Mora, the Cypris-larve of Balanus and
some others, the habit is adopted, I believe, with a definite
object, there are many instances where it is practically certain that
the flotation is not voluntary and is accidental, the animal having
either jumped or been splashed on to the surface, where it is retained
by tension of the water-film, till, by a vigorous effort it breaks through
and is able to descend beneath the surface.

In confinement, I have several times noticed anemones, chiefly
Actinoloba dianthus, floating on the surface, foot upwards, suspended
by the action of surface tension: This obviously is a ready mode of
transport but how far it is accidental and induced by the unusual
nature of its environment is difficult to determine, though as
Actinoloba often frequents quiet land-locked localities, e.g. South-
ampton Water, where perfectly smooth water is of common occurrence,
it may be that it is a natural habit. Actual observation in such
localities is therefore required to determine the question.

As to the Molluscs, the smaller ones, such as Hlysia, which
commonly frequent tidal pools where the water is normally quiet,
certainly do make use of this mode of progression, but it is more
than doubtful if the large Doris do under purely natural conditions.

It is, however, among the Crustaceans that real service is
obtained by animals from the phenomenon of surface tension. To
the other groups it is at most but of very occasional use ; to Nebalia,
Cirripede pupal larvee, &c., it is of constant value, and of the highest
importance in the routine of their life history, indeed as regards the
Cypris larve, very much emphasis must be laid upon the correlation
of this peculiar flotation with the special habitat of the adv/t animals.

Woe 2, Ele WIL,

Journ. of Mar. Zool. & Microscopy.

I

My,

\\

"
Wi A

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aD NAT.

vi EXCEPTED)

JAMES HORNELL, Det.
(Fic.

AURELIA AND PLUMULARIA.,

WOIbe By Pile WIN.

Journ. of Mar. Zool. & Microscopy.

JAMES HORNELL, Det. avd Nat

Fiegs. A, B, C & 1.

Cele ALO OIDIN,

THE PERMANENCE OF THE SCYPHISTOMA STAGE
OF AURELIA.

BY JAMES HORNELL.

Three years ago, in 1893, large numbers of the Scyphistoma or
Hydra-tuba stage of the Medusa Aurelia auwrita appeared on boulders
in several of the tanks of the Jersey Biological Station. Since then,
colonies produced from these individuals have been permanent on the
same stones. ‘he continuity has been absolute, individuals having
practically been under daily observation since their first appearance.

Under favourable conditions of food supply and temperature the
increase in their numbers by budding was very rapid. The buds
grew out from any part of the body; lengthened each into a
stolon that crept along the rock till some quarter inch away from the
parent, then made adhesion by a part that would finally become the
basal disc, quickly budded forth a ring of tiny tentacles, opened a
mouth aperture and finally constricted and then cut through the bond
with the parent, the two parts of the stolon being absorbed by the
respective individuals. Sometimes a Scyphistoma would give off two
or even three stolons at the same time, and as the growth of the young
individuals from these outgrowths is sometimes very rapid, the vast
increase of the colonies is comprehensible. No wonder that Aurelie
some seasons swarm in countless millions in our seas !

‘While this process of multiplication goes on very rapidly during
the greater part of the year, towards the end of January and the
beginning of February a second mode of reproduction, strobilation,
takes place. This, as is so well known, is the constriction of the
polyp-like body of the scyphistoma into short-armed plate-like divi-
sions or discs, arranged in a manner similar to a rouleau of coins.
One by one the discs broken off from the stock, float away as ephyre
—little pulsating plates that by gradual change and growth, pass
imperceptibly into the adult sexual medusa, the female producing
ciliated embryos that, after a short free-swimming existence, settle
down, form tentacles and mouth and assume the alternate sexless or

Scyphistoma-stage.
Every year since 1893, my captive colonies have thrown off their

ephyre,but the individuals never assume the polydisc or typical
form, usually—I believe—most common in strobilating individuals
in the open sea. Mine have all been monodisc strobile, producing
not arouleau of ephyrez discs, but each a single ephyra. This I am
inclined to attribute to a lower vitality than is posessed by those in
the sea, induced by the smaller food supply available in the tank
water, which is to a large extent filtered prior to admission to the
tanks.

Apparently a colony can exist indefinitely ; the specimens I now

JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

have are exastly of the same appearance as those that appeared three
years ago, save that they have spread and multiplied exceedingly.
Excepting accidents they are likely to exist as long as they receive
the moderate attention they have had so far. I do not, however;
mean to assert that the same individuals are now alive as in the
beginning, though it is probable they may live two or more seasons.
The chapter of accidents is long and those living to-day are in most
cases, at least, the budded off and replace successors of the original
ones.

On Pl. VI., figs. A. to D., are drawn a group of four as seen when
in active budding on Christmas Day, 1894. They were: attached to
the side of a bell jar in a most favourable position for observation.
Fig. A* shows side view of one of these to show how in some
eases the stolon has been given off from the polyp body at a point
considerably above the attachment dise ;: thus the stolon bends down
to root at a distance from the parent, after the fashion of the branches
of the banyan and the mangrove. In others it emerges low down as
at fig. C*.

EXPLANATION OF Ph. VI. Fires. A To C.

Fig. A,B, C & D. A group of Seyphistomata of Aureha aurita,
drawn on Christmas day, 1894, when attached to the
side of a bell jar. d is the adhesion disc, 4 a prolife-
rated bud ; B shows in the best manner, the development
of a stolon. A*and C* are profile views of A and C

respectively.

MICROSCOPICAL STUDIES IN MARINE ZOOLOGY.

BY JAMES HORNELL.

STuDY XXI.—THE PLUMULARIDA.

None of our Zoophytes are more graceful than are the Plumu-
laride—their form justly entitles them to the name they bear, so
exquisitely beautiful are their feathery plumes, borne sometimes on
the green blades of the sea-grass (Zostera), or on the stout brown
edges of Fucus, or even on the bare rocky sides of some sheltered
pool.

Very nearly related in general form to the Sertularide, this family
differs in two important points: in the former, the polyps are
arranged along both sides of the branches, in the latter, a row is
found on one side only ; again, among the Plumularide, minute and
degraded individuals are found, known under the name of nemato-
phores—organs entirely wanting among the Sertularide. In the
species here figured, one occurs just beyond, and another below each
hydrotheca, whilst two are located in the axils of the stem and
branches. Considerable mystery attaches to these structures, their
function being still problematical. In form théy are tiny chitinous
cups wherefrom project extremely extensile sarcodal threads. The
term sarcotheca is applied to the cups; sarcostyle to the thread.
The latter, though extremely slender and tenuous, and not unlike
the gigantic pseudopodia of some monstre Foraminiferon, are truly
cellular, composed of an outer ectodermal layer sheathing an endo-
dermal core. A remarkable feature is the projection of pseudopodia-
like processes from the surface of the sarcostyle. The cell-walls are
all extremely tenuous and thus capable of great elongation. The
extensile power of these threads is indeed marvellous. Fig. VI.,
Pl. VI., gives but a faint idea of this. When active, they may be
seen winding and coiling with snake-like litheness around the hydro-
. thece and the branches. Especially active are they in the neigh-
bourhood of dead polyps, and here perhaps is their sphere of useful-
ness, in the removal of decaying matter—a theory strengthened by the
presence of foreign particles in certain amceboid cells of the surface.

The great reproductive capsules or gonangia are especially well-
developed in this species, crowding the lower end of the main stem
(hydrocaulus), the lower branches, and especially the creeping
stem or stolon that connects the various plumes of the commonwealth.
In these the reproductive cells mature and undergo segmentation,
' but, thanks to Weismann’s researches (Die Enstetnung der Sexual-
zellen ber den Hydromedusen) we now know that in this family, the
Plumularide, they do not originate within the gonangia, but arise in
the endoderm of the stem, whence they migrate to the gonangia as
into incubatory pouches. Figs. 3,4 and 5, Pl. VI., illustrate these
protective sacs in various stages, and show how the sexual cells con-
gregate in a spherical mass—a false ovary.

64 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

The family Plumularide isrepresented by three genera in British
waters, Plimularia, Aglaophenia, and Antennularia. The last
named is distinguished by the whorled arrangement of its character-
istically short or bristle-like hranches. The two former are plu-
mously branched ; in Plumularia, the gonangia are scattered along
the branches and the stems; in Aglaophenia, they are collected into
great basket-like structures, called corbule, formed by the modifica-
tion of an entire branch or pinna. The arrangement of the nema-
tophores is also distinct in the two genera.

EXPLANATION OF Pu. VI; Fies. I. To V. '

Fig. I. Natural appearance of fronds of a species of Pluwimularia
growing upon the extremity ofa blade of Zostera. The
black buds are gonangia, attached to the creeping and
connecting stolon or hydroriza and to the lower parts
of the fronds.

Fig. IJ. A young frond, greatly enlarged, showing polyps in various
positions, and also the position of the nematophores (72)
both below and above the hydrothece, and in the axils
of the branches ; dh. developing hydranth ; dic. deve-
loping extremity of the stem or hydrocaulus.

. TIL, 1V.and V. Various stages in the history of a gonangium ;
0. OVA.

Fig. VI. Shows two nematophores of another species. . the

chitinous sarcotheca, emitting the highly extensile
whip of sarcostyle (atter Hincks).

Fi

03

STuDY XXII.—THE EGGS AND YOUNG OF CEPHALOPODS.

In the Cephalopods, we see the highest development of the Mol-
lusca, a superiority at once obvious when we consider their powers
for rapid losomotion, their powers of offence, their keen vision, and
the large size of their central nervous mass, the brain. In their
development, this vast gap that separates them from their fellows in
the common phylum, is emphasized strongly. Lamellibranchs,
marine Gastropods, &c., have all one characteristic larval form, the
veliger—a tiny, free-swimming larva propelled by powerful cilia,
and housed in a transparent shell. Among Cephalopods no trace of
this is seen.

Of the species found upon -our coasts, the large Loligo Forbesii
deposits her eggs in masses of candle-shaped cocoons, attached at one
end to seaweed or other objects. This spring, on one occasion, we
found a considerable number of cocoons attached to the buoy rope of
a lobster pot (Plate VII., Fig. A), from which they hung in bunches,
recalling the primitive “dip” candles of auld lang syne. These

MICROSCOPICAL STUDIES. 65

cocoons are transparent, gelatinous, and tough, and composed of
several layers, enclosing a large number of eggs—each egg in turn
encased in a transparent spherical membrane.

The course of development of the embryos is abbreviated, for
when they free themselves from ths egg-membranes, they possess
the general structure of the adult. Indeed, as soon as born, they
swim and dart about with all the confidence of full-grown indivi-
duals. Even the ink bagis developed at the time of hatching, and
is to be seen as a tiny black spot, and upon irritation, the little crea-
tures can cause the contents to be ejected in a tiny black cloud.
There are also present chromatophores—very conspicuous vesicles
of pigment, governed by sets of muscles that produce by alternate
expansion and contraction the pretty blushings and pallor so marked
a feature among the adult Cephalopods. I noticed, however, that
the chromatophores are normally kept in a state of contraction so
long as the animal is unhatched, the whole mass being glassy trans-
parent till then. For a long time before freedom is gained, the
embryos can move freely in their capsules. In these young forms,
a tiny remnant of the yolk sac, attached in the centre of the arms, is
sometimes unabsorbed at the moment of birth. Two flap-like fins
are present at the extremity of the abdomen—and of very different
shape to the adult fins.

The young of Sepia have a similar history, but here the eggs are
laid in separate egg capsules and not in cocoons. Black and of the
form of grapes, these eggs produce each a single embryo.

In. the mounted specimens of the embryo, notice the pair of gills at
the hinder part of the mantle cavity, a number characteristic of all
living Cephalopods excepting the pearly Nautilus which possesses
four gills. On this account we class all Cephalopods as either
DIBRANCHS or TETRABRANCHS. The present day representatives of
the class are grouped as follows :—

Class :—CEPHALOPODA.
ORDER I :—TETRABRANCHIATA. One living genus only ;—
Nautilus.
ORDER IT :—DIBRANCHIATA.
SuB-ORDER I :—Octopoda (possessing eight arms), whereof the
best known genera are Argonauta, Octopus, and Eledone.
SuB-ORDER II :—Decapoda (possessing ten arms), containing a
very large number of genera; among others being Sepia,
Sepiola, Loligo, Rossia, Ommatostrephes, Loligopsis, and
Spirula.

EXPLANATION OF Pu. VII. Figs. A. B. & C.

Fig. A. A cluster of egg capsules of Loliga Forbesi, attached to a
rope. X 4.

66 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

Fig. B. Young of L. Forbesii just after it has broken through the
egg membrane ; chromatophores shown relaxed.

Fig. C. The same viewed as a transparent object. /f. fins; g. gills;
7.ink sac; rd. radula; s. siphon; x, chromatophores ;
y. remnant of yolk sac, as yet unabsorbed; the eyes are
shown in optical section.

srupy XXIIlI.—THE VISUAL ORGANS OF THE MOLLUSCA.

The organs of sight in their frequently perfect adaptation to the
sensory function they perform, claim our admiration \in a degree
greatly superior to that which we accord to any other organ of the
body. Nor is our interest lessened when we see the manifold modi-
fications of structure presented by them; how, even in the same
phylum, one family may be endowed with such organs formed in the
most complex manner, whilst closely related forms may possess but
the simplest of structures, crudely functioning towards a similar
end; how here, the optic mechanism is prominently and closely
associated with the brain; how, among others, organs arise inde-
pendently from the most diverse regions to assume a physiological
equality with the cephalic eyes of other types.

Nowhere do we find greater variability in the origin and structure
of the visual organs than among th: Mollusca. Thus, while the
Gastropoda and the Cephalopoda possess paired cephalic eyes, the
Lamellibranchs possess none, their place being taken by numerous
peripheral eyes arranged along the edge of the mantle.

In structure, apart from the mere pigment spots that are borne
upon the extremities of thesiphons in Solen, Venus, &c., there exist
five principal types of eye among the Mollusca.

The simplest form, found in the eyes of the Limpet (Patella), is
a mere bowl-shaped depression of the epidermis, the lining of which
has become modified into a visual layer, or retina, mto which the
optic nerve penetrates by numerous fibre-branches. A slightly higher
modification is seen in the eyes of Nautilus, where the ocular pit is
excavated out of a broad conical stalk, and with the aperture con-
stricted to a mere pin-hole, the whole recalling forcibly both the
outline and the section of a young Fig-fruit. In this eye, as in that
of the Limpet, the retina is bathed directly by the sea-water. (Figs.
Hil, aya) IDX Tei, WAU)

The second type of Molluscan eye shows considerable advance
upon the first. It has the form of a closed capsule and is directly
derivable from the simple cup-form, by the ingrowth and fusion of
the lips of the cup. This optic capsule usually separates from the
epidermis from whose ingrowth it arose, the superficial epidermal
layer closes over, becomes transparent, and then may be termed a
cornea, as it becomes a transparent protective window for the capsule

MICROSCOPICAL STUDIES. 67

beneath. Anotheradvance is made by the formation of a gelatinous
substance in the cavity of the capsule. This is a vitreous humour
and is a prelude to the appearance ofa lens. The eyes of the Roman
Snail (Helix pomatia) and of Tritoniwm are typical examples.

The third type, found solely among the Cephalopoda, is formed in
direct sequence with the form last mentioned, but before treating of
its origin, we will detail the chief points in its structure, taking for
our text the eye of the Cuttlefish (Sepia officinalis). In this species,
as is usual among the Cephalopods generally, the eyes are placed
prominently upon either side of the head. Hach consists of a hollow
bulb sunk in a deep orbit in large measure hollowed out of the
cephalic cartilages. This orbit becomes a closed chamber, the optic
capsule, by the extension across it, and in front of the optic bulb, of
a transparent fold of skin, which functions as a cornea.

If we now bisect the optic bulb we find it contains but a single
chamber filled with gelatinous vitreous humour, bounded in front by
a very large bipartite crystalline lens, and elsewhere by thin walls
that are stiffened, and thus prevented from collapse, by the presence
of delicate plates of cartilage in their middle subtance. External to
these cartilages, and obvious to the naked eye asa brilliant bronze-
hued coating, are two layers of pigmented membrane, the argentea
externa and interna.

Internal to the cartilaginous and fibrous layers of the bulb is the
retina, lining the hinder part of the ocular cavity, the front being
occupied in large measure by the lens. The latter is almost globular
in shape, the longest diameter coinciding with the visual axis. It is
made up of the junction along a transverse plane of two unequal
plano-convex lenses. The anterioristhe smaller. Asa consequence,
the posterior has much greater convexity, and projects boldly into
the ocular chamber. Afier hardening in spirit or otherwise, each
portion of the lens can readily be split into a large number of con-
centric layers, whose curvature coincides with the external convexity
of that half of the lens to which they respectively belong. A fine
membrane stretches across the lensat the junction of the two halves,
and passes at the edge into a fibrous and muscular sphincter-like
organ, known as the ciliary body. This, in turn, merges with the
fibrous wall of the ocular bull. The use of this ciliary body is the
regulation of the convexity of the lens, to permit of its adaptation to
near or to distant vision.

A fold of the external coat of the bulb is carried part way over
the outer aspect of the lens, and is the iris entrusted with the im-
portant duty of regulating the quantity of light passing through the
lens. It is strengthened internally with thin plates of icartilage. In
Sepia, it has an upper and a lower fold that have much superficial
resemblance to eyelids and give the eye aslit-like pupil. In passing,
it may be mentioned that Sepia possesses a true eyelid, consisting of

68 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

a horizontal external fold of skin extending along the lower side of
the eye. In Octopus the eyelid is sphincter-shaped.

The retina, bounded internally by a thin transparent or hyaline
membrane, consists of two distinct portions, the outer and the inner,
separated by a sharply defined layer of black pigment. The inner
layer is made up of rods, the outer of nerve cells and nerve ramifica-
tions. The optic nerve in Cephalopods is very short and stout. On
entering the optic capsule it forms an immense ganglion whence
arise very numerous nerve fibres. ‘hese gain access to the interior
of the optic bulb through sieve-like openings in the cartilaginous
layer of the wall of the bulb. Thence they pass to the external
surface of the retina. In front, and partly at the sides, of the gan-
glion lies a peculiar soft whitish organ, the white body (w.d.).

Examined superficially, the general structure of such an eye
seems partially identical with that of a Vertebrate eye, except in the
absence of an anterior chamber. In reality, there are some very
radical divergences ; thus in the Cephalopoda the retina has its layer
of rods turned inwards, t.¢., pointing towards the interior of the eye ;
in Vertebrates, this layer of rods is external, directed outwards; in
Cephalopods the pigment layer divides the retina into two regions ;
in the Vertebrates it lies external to the rods and cones. Most im-
portant difference of all, the optic fibres proceeding from the large
optic ganglion pass into the retina from the exterior in Cephalopod
eyes, whereas in Vertebrates the optic nerve forms no ganglionic
mass, but passes through the wall of the optic bulb by a single
opening and then breaks through the retina in the same way,
spreading a network of fibres over the znternal surface of the retina.
Hence light entering the eye of Cephalopods, impinges first upon the
retina and passes directly downwards to the nervous layer beyond.
In the Vertebrate eye, the impressions of sight fall first upon the
nervous layer, are transmitted thence through the various layers till
the rods and cones are reached and thence returned by them through
the same layers to the nerve fibres upon which they first impinged.
This fundamental divergence is clearly diagrammatised in figs. X.
and XI., Plate VII.

A less important difference is that of the cornea being part of the
optic bulb in the Vertebrates, separate and part of the optic capsule in
the Cephalopods.

In the latter the bulb represents the Vertebrate eyeball, minus the
cornea and sclerotic, the equivalents of these being here possessed
by the optic capsule, which here functions as an orbit.

The development of the Cephalopod eye is very instructive, both
as throwing light on its origin and relationship with the other forms
of molluscan eyes, and also in regard to the origin of its divergences
from the Vertebrate type of eye. Figs.I. to V., Plate VII. graphically
describe the stages.

The earliest stage (Fig. II.) is the equivalent of the optical stage

MICROSCOPICAL STUDIES. 69

attained in the eye of the Limpet ; the epidermis at one spot, having
sunk down to form a shallow depression wherein the cells forming
the floor of the cavity constitute a primitive retina.

In Fig. III., the edges of the optical pit have grown horizontally
inwards so as to reduce the mouth of the pit to a small round open-
ing. This pit raised up on a stalk marks the permanent condition of
the eye in Nautilus (Fig. [X.). In the embryo Sepia, the aperture is
early obliterated by the approximation of the free edge of the epi-
dermal fold. This accomplished, we havea hollow globe formed
overlaid by a continuous epidermal layer (e, Fig. IV.) A condition
of eye exactly corresponding to this stage, is the adult form of eye of
Helix as described above.

By a second downgrowth of the surface epidermis, another pit-
like cavity is formed, the floor of which impinges upon and fuses
with the anterior wall of the previously formed hollow ocular sphere.
Fig. V. illustrates this stage. At the centre of the area where the two
layers fuse, a transparent nearly spherical body, the future lens,
begins to form. According to Carriere the external of the two fused
layers forms the external part, whereas the anterior wall of the optic
sphere forms the larger internal half. Hence the plane of division
that cuts the mature lens into two parts represents two fused epi-
dermal layers, and the fibrous strands of which it is composed merge
equatorially into the surrounding ciliary body. The lens itself is
composed of structureless layers, that are however only revealed
after treatment with chemical reagents. Naturally, it is transparent,
tough, semi-gelatinous, and apparently homogeneous. The folds in
front of lens (¢) represent the origin of the ultimate iris ; the cornea
is likewise formed by another fold of the epidermis turning inwards
and fusing in the same manner as-the layer e in figs. III. and IV.

The mature form of the eye is now reached, the posterior wall of
the ocular sphere becoming modified into the retinal layer by
differentiation of the cells. Comparing the development of the
vertebrate eye, we find the retina is there formed, not directly from
an epidermal invagination, but as an outgrowth from one of the
primitive vesicles of the brain (Fig. VII.), which eventually assume
the form of a double walled stalked cup, through the external wall
of the outgrowth becoming pushed in upon itself, while the hollow
stalk comes finally to represent the optic nerve. Synchronizing with
these changes, an epidermal invagination has been taking place,
which by ingrowth of the lips is at first a closed sac connected at one
spot with the overlying epidermis, but which is quickly severed and
sinking inwards, is subsequently converted into a transparent lens,
filling the mouth of the retinal cup. The cornea here, as in the eye
of Sepia, is formed by the epidermal layer that overlies the lens
losing its cellular nature and becoming transparent and colourless.

It will be seen from the foregoing that in Sepia, except for the
nerve fibres that surround and penetrate the retina, and for the

“70 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

“supporting tissues (cartilages, muscle fibres, &c.) of the wall of the
bulb, all parts of the eye have direct epidermal! origin, whereas in
the Vertebrate eye the cornea and lens alone have direct epidermal
origin, as the retina is entirely derived from an outgrowth from the
embryonic brain. The heavy black lines in Figs. III. to VII. indicate
the external margin of the layer of retinal rods. They show how in
in the Cephalopod eye this layer is turned towards the light, while in
the Vertebrate eye it is turned in the opposite direction. Thus
while the higher Cephalopod eye reaches what is practically the same
perfection_and same plan of optical mechanism as the Vertebrate eye,

“it does so by a different avenue of development.

As already noticed, the majority of Molluscan eyes belong to one
or other of the three types so far described, and which may be
exemplified respectively by the the eyes of the Limpet, the Snail and
the Cuttlefish, ranked in order of development. These in structure
and development are in direct sequence. ‘Their homologies are
definite and fixed. All are cephalic eyes, and in close relationship
to the central nervous mass.

Hence, when among the Pectens and allied Lamellibranchs
we find visual organs that from their position are obviously not
homologous in origin, it is specially interesting to see what

differences in structure prevail. Im such forms cephalic eyes are
wanting, their place being taken by small organs placed upon short,
deeply pigmented papille, arranged a. intervals along the edge of the
mantle or pallium, whence they derive their name of pallial eyes.

Stated briefly the structure is as follows. The ocular papilla is clothed
with an epithelial layer, deeply pigmened except at the summit, where
the cells are colourless and flattened. Beneath this layer lies the tiny
ocular sphere divided into two halves by a partition, the anterior
containing a transparent cellular lens, the posterior, a several-layered
retina of ordinary structure. The arrangement, however, of the rods
and cones is the reverse of that found in the cephalic eyes of
Molluses, as they are here turned away from the light and are under-
laid by a pigmented layer. Again fibres from the optic nerve
form a layer anterior to the other retinal layer, so that light must
traverse this nervous layer before it can reach that of the rods and
cones. The plan of structure is therefore practically identical with
that found in the Vertebrate eye save that the optic nerve does not
pass through the retina, but attains its connection with the rods and
cones by passing around one side of this layer and thence spreading
out over the distal surface.

Very curiously nearly similar eyes are found upon dorsal processes
in a'peculiar Gastropod, Onchtidiwm, and here even closer approxi-
mation is made to the plan of the Vertebrate eye. Instead of the
optic nerve turning the fiank of the rods and cones, it passes through
at one point, thereby producing a blind spot exactly analogous to
that found in the Vertebrate eye. This eye of Onchidiuwm constitutes

MICROSCOPICAL STUDIES. 71

the fifth and perhaps the most interesting of the types of Molluscan
eye—for, standing as it does alone, it furnishes us with one of the
most remarkable instances of independent evolution that we are at
present aware of.

And in this connection it is important to notice that no other
organ has had so many independent evolutions as has the eye.
Nothing could so strongly emphasize the supreme importance of
sight to the majority of creatures. Here, within the types referred
to above, four distinct evolutions of ocular organs undoubtedly took
place. No one can for a moment deny that the cephalic eyes of
Cephalopods and of Vertebrates have had independent and conse-
quently dissimilar origin. Hmbryology at once marks out this
divergence ; while the peripheral position of the eyes of Lamelli-
branchs is sufficient to separate them from each of the former. +
Again one cannot gainsay divergence of origin to the dorsal eyes of
an aberrant Gastropod and the pallial eyes of the Lamellibranchs.
If only our knowledge of the homologies of the more obscure
organs were on a par with that of the eye—though much remains to be
done even here—our attempts at constructing phylogenetic tables or
trees of descent, would be infinitely simplified. Indeed, it maybe
considered a biological axiom that no reliable phylogenetic tree can be
constructed till the homologies of individual organs have been exhaus-
tively made known.

EXPLANATION OF Pu. VII. Figs. 1. To XI.
The Cephalopod Eye.

Wig. I. Section through eye of Sepia officinalis. ae. argentea
externa; ey. eyelid; c. cartilages of optic bulb; ce.
cephalic cartilages; ci. ciliary body; co. cornea; gn.
optic ganglion; ir. iris, showing a thin plate of
strengthening cartilage; /. lens; on. optic nerve; p.
retinal layer of pigment; 7’ internal layer of retina;
ry”? external layer of retina ; wb. white body.

Figs. II. to V. Diagrams of the chief phases in the development of
the Cephalopod eye. III. represents that stage which
in Nautilus is the permanent condition; LV. is prac-
tically a diagram of the eye in Helix; e. unmodified
epidermis; /. lens; 7. retinal layer; a thick black layer
denotes the position of the distal margin of the layer of
rods and cones.

Figs. VI. to VIII. Diagrams illustrative of the development of the
Vertebrate eye. 0. represents a hollow outgrowth from
the brain which eventually form the retina and _ the.

72 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

optic nerve. In Fig. VII. the epidermis is sinking
downwards to meet this hollow outgrowth, while in
VIII. it has become pinched off and forms now the
basis of the future crystalline lens. e. epidermis.
(Figs. II. to VIII. are after Carriere, “‘Die Sehorgane der Thiere,”’
Miinchen and Leipsig, 1885).
Fig. IX. Diagram of the structure of the eye in Nautilus; on.
branches of the optic nerve ; 7. retina.

Fig. X. Diagrammatic representation of the eye structure in Cepha-
lopods, to show the arrangement of the retinal elements
in relation to the optic nerves. (After Graber).

Fig. XI. A’similar representation of the retinal arrangement, &c.,
of the Vertebrate eye. (After Graber).

September 10th, 1896.

Ghe Journal of Marine Soology
and Stlicyoscopp ;

A PLAINLVY-WORDED BIOLOGICAL MAGAZINE.

NO em yes NO Sa iG Hvis Hire... 168907.

The Possibilities of Fishery Improvement
in Jersey ;

With Notes on the Present State of Marine
Pisciculture and Fishery Regulation. *

BY JAMES HORNELL
{ Director of the Jersey Marine Biological Station /.

1. The continuous decay of inshore fisheries, here and abroad; the chief causes locally.
2. Remedial measures pursued elsewhere.
3. Scope and Programme of the investigations and experiments requisite locally.

4, Summary of the Fishery Laws having force in Jersey; their inadequacy to meet
present requirements.

5. Forecast of the probable outcome of an adequate local fishery investigation.

Part 1.—The continuous decay of inshore fisheries and the chief
local causes.
DuRiInG recent years, in well-nigh every fishing hamlet in Great Britain
the plaint of lessened catches in the places where fish formerly abounded
has been practically unanimous. The total catches landed on the quays
have, however, not decreased ; on the contrary, by the employment of
powerful steam trawlers able to fish far from home, by the longer
journeys made by sail-trawlers and by the larger liners, and by the
invention of improved methods and appliances, the fish supply of Great
Britain has materially increased, but an increase entirely obtained from
extra-territorial waters. The inshore fishermen, such as we have in
Jersey, the men who fish in small undecked boats, have no share in this
prosperity; these men find their own particular grounds rapidly becom-
ing depopulated, and, unable to seek the more distant fishing-grounds,
are compelled either to seek new occupations or to languish on earnings
that are miserably insufficient. Along the French coast a similar evil
state of matters exists; thus, my esteemed friend Dr. Canu, Director of
the Station Aquicole at Boulogne, and the foremost authority on piscicul-
ture in France, writes :—‘‘ In the Eastern portion of the English Channel,
the maj ority of the banks formerly frequented on account of the number

* A lecture delivered under the auspices of the Jersey Natural Science Association “at

the Hotel-de-Ville, St. Helier, Jersey, October 6th, 1897.

74 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

and the quality of their fish, have long since witnessed the loss of their
reputation; they are even partially abandoned.” And again: ‘The
diminution of fish catches on the banks which line our Channel coast can
no longer be disputed.” . . . ‘‘ The decrease of our small Northern fishing
ports is more eloquent than any statistics upon this point.” So well
authenticated and so well recognised by the fishers themselves is this
decadence in Jersey, that it requires little or no demonstration from me.
Indeed; in view of the absence of local statistics as to catches, it is
impossible of verification in figures. However, I have the authority of
our best informed fishermen for stating definitely that a diminution of
30 per cent. to 40 per cent. has been observable in their catches of many
of the most important of our local fishes during recent years, such as
sand-eels, gras-dos (smelts), gurnard, conger, whiting, sarde (red bream),
flat-fishes, &c., to say nothing of the dead oyster and ormer fisheries, or
of black breams and lobsters, about which we have statistics, definite and
incontrovertible. The decrease which is caused by actual searcity of the
fish themselves is most marked in the catches of the flat-fishes generally
(plaice, soles, turbots, &c.), the bream, sand-eels, gras-dos, and lobsters ;
in the case of the larger round fishes such as the whiting and the eonger,
the cause is probably due to the marked decrease in the supply of bait
available in Jersey, especially so in the case of the squids (Sepia and
Loligo), and of the ‘‘ red-cat ” bait worms (Vereis). Seven or eight years
ago plaice of large size were common in the large bays, measuring some
fourteen inches long on the average ; to-day such fine fish are extremely
rare, and our market depends for its supply upon imports from Plymouth,
Lowestoft and Grimshky. It is significant to notice that this deeline in
plaice coineides with the sudden increase in the use of set-nets and draw-
nets in our bays that occurred some few years ago. Again, ten years ago
over forty boats hailing from the south coast, from La Rocque, Pontac,
St. Clement, St. Helier, and St. Aubin, earned large profits from the
breaming industry. This year the number was reduced to some half-
dozen boats taking largely reduced quantities. As to lobsters, I have
been fortunate in being kindly permitted access to certain private statis-
tics going back over thirty years; and while I am not permitted to quote
figures, I may say that the decrease has progressed with ever-increasing
and most alarming rapidity, while the present year is practically the
worst on record.

Tt is pertinent at this point to ask what are the probable causes of
such decrease. The chief may be listed as follows :—

a. The use of nets of destructive form or with meshes of insufficient
size, whereby there is a pernicious destruction of immature fish.

6. The want of adequate protection accorded to fish during the
breeding or spawning period and also while immature. The latter are
of trivial value as human food, but by reason of having survived through

FISHERY IMPROVEMENT IN JERSEY. 73

the fry stage, that period of their lives most fraught with danger, they
would possess a great potential value if left in the sea to mature. As
regards plaice and lobsters, we have a law affording protection until they
reach the size of nine inches ; but though the law is good, it has become
valueless as we do not seem to possess police machinery to enforce it.
As a consequence certain people have been known to feed their pigs with
multitudes of tiny plaice taken in set nets in St. Aubin’s Bay, while at
every Spring tide, hordes of men and boys invade the littoral armed with
basket and hook, bent on an indiscriminate collection of crabs and
lobsters of any size procurable. I have known as many as 200 immature
Guernsey crabs (Cancer pagurus) in one man’s basket, not one of which
was of the proper size of 44 inches across the back, while time after time I
have seen men bringing back six to twelve or more lobsters averaging from
five to seven inches long. What wonder, then, that after such improvi-
dent and senseless procedure, there should ensue a period of dearth?

ce. Insufficient supplies of bait, especially of squid, ‘ red-cat ”’ worm,
and sand-eels. As regards the ‘“‘ red-cat’”’ worm (Werevs cultrifera) once
so abundant, and now extremely scarce, the harm has arisen through
lack of protection afforded during the breeding season, and from the
free and unrestricted digging permitted.

d. Trawling within the three-mile limit is considered by liners as
highly prejudicial on account of the wholesale destruction it effects. In
Scotland trawling is now prohibited, both within the three-mile limit
and also in certain of the great bays or Firths, and many authorities
are extremely anxious to have the range of prohibition extended further,
so that the territorial waters shall form a zone of, say, seven or even
thirteen miles in width, wherein trawling shall be rigorously suppressed.

e. Competition at a disadvantage with larger and better equipped
French craft, which constantly infringe upon the territorial waters round
our island—the special heritage of our own men. From their larger size
and better supply of bait, these boats are enabled to keep the sea longer
than our boats, and as a consequence they can remain longer upon the
fishing grounds. A great source of annoyance to our men lies in the
fact that these boats after poaching all night in Jersey waters, sail into
the harbour here and dispose of their fish—congers chiefly—without
paying duties or impét, whereas our men are debarred by the high
protective tariff from selling their catches in French ports, a hence
have to restrict their runs to the vicinity of Jer sey.

Part 2.—Remedial measures pursued elsewhere.

The premises granted, if we wish to be in a position to apply
remedies, it is essential that we should know what practical measures
are being pursued successfully elsewhere towards this end. Such
measures are divisible into two classes—those that aim at the protection

76 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

and efficient regulation of fisheries now existing, and those strictly
scientific remedies where artificial means are taken for the re-stocking of
extinet or moribund fisheries by means of hatchery and planting.

Protective laws are no creation of to-day ; to go no further back than
the time of the Seeond Charles, we find Parliament and local authorities
passing measures for the regulation and protection of fisheries. Thus
we have ameng other measures, ‘‘an Act for the regulation of the
sardine fishery in the counties of Devon and Cornwall,” while, in 1663,
we find that the long-headed folk of Edinburgh, alarmed for the welfare
of their oyster-beds, drew up detailed regulations to prevent abuses, and
to ensure if possible a continuance of prosperity.

The difficulties in the way of rapid transit from the coast to the great
inland centres of population barred the way to any extensive expansion
of fishing industries until the advent of the railway system. From that
period onward the trade has grown by leaps and bounds, and, as was to
be expected, Fishery Commissions, Regulations and Laws, appeared
with ever-increasing frequency. A host of regulations as to the form of
nets, the size of meshes, the minimum size of immature fish, close times
and the hke have thus been promulgated, amended, abrogated, renewed
and so on from time to time; but until twelve years ago, when the
Board of British White Herring Fishery was reconstituted with inereased
powers as the ‘‘ Fishery Board for Scotland,” there was little or no
attempt at any comprehensive and continuous series of scientifically
carried out investigations and experiments to serve as secure bases for
the enactment of remedial measures. With the advent of this Scottish
Board we had for the first time in Great Britain the provision of adequate
and sustained means for the enforcement of such regulations as are
desirable, while from the constitution and powers of the Board, sufficient
elasticity is present to permit of local needs receiving due attention.

Immediately following this epoch-making event, another very great
and real impetus was given to the organization of our fisheries on true
scientific lines through the wonderful interest aroused in the welfare of
this industry by the great International Fisheries Exhibition held in
London in 1883, the way for which had been opened by the pioneer
Exhibitions of Norwich and Edinburgh that had worthily preceded it.
Largely from the attention thus focussed upon fisheries, a healthy public
interest was aroused, and the natural results followed, when, as one item
in local government, powers were granted some eight years ago to county
councils in England and Wales to form local fishery committees for the
protection and improvement of the fisheries along their littoral, and to
formulate by-laws caleulated to this end. Such powers were gradually
availed of, and with varying energy the fight has been begun all along
the English coast line. Controlled by special local needs, and necessarily
tentative as much of the work has been, great good has undoubtedly

FISHERY IMPROVEMENT IN JERSEY. el

accrued. With the increase of knowledge given by continued experiment,
and greater experience, the authorities concerned are well satisfied that
future progress is assured. Intense hopefulness is essentially the charac-
teristic of those actively engaged in these remedial measures, so solid has
been the progress made, considering what obscurity enveloped so many
of the problems when they were grappled with.

Of the various English Sea Fisheries’ Committees, that of Lancashire
holds the premier position, alike in priority of origin, in the able and
practical administration and scientific conduct of the work, and in the
amount of practical good already resulting and abundantly apparent
from its efforts. Hence a brief sketch of its work will be useful to
detail, especially as I have personal knowledge of the district in question.

The Lancashire Committee, as soon as the proposed amalgamation
with the Western Sea Fisheries District is completed, will exercise
control of a coast line of 345 nautical miles and over an area of terri-
torial waters of some 1,300 square miles. ‘he administrative staff
consists of a superintendent, seven fishery officers or water bailiffs, and a
steamer crew of six, also empowered to act as bailiffs. For the use of
this department a powerful screw steamer, the ‘‘ John Fell,” is provided,
together with three sailing cutters of about ten tons each. ‘The scientific
work is carried-on by the Hon. Director of the Fisheries’ Laboratory,
Prof. Herdman, F.R.S8., with the assistance of two trained investigators.
This scientific staff possess two laboratories for investigation, one at
University College, Liverpool, and the other at Roa Island, Barrow-in-
Furness—the latter a large building fitted with gas-engine, tanks, and
other appliances for the hatching and rearing of fishes.

Work accomplished :—After numerous long-continued experiments a
code of bye-laws was framed, of which the following is a summary as
furnished by Mr. Dawson, the Superintendent: ‘‘ Only nets can be used
which will allow fish of small size to escape through the meshes; a
certain area off Blackpool where young fish are found in great abund-
ance, is closed entirely to all net fishing, except drift-net fishing, sea fish
taken in shrimp nets along with the shrimps have to be picked out and
thrown overboard as soon as possible, crabs, lobsters, mussels, cockles,
and oysters may not be taken under certain sizes, and no berried lobsters
or edible berried crab may be taken; forms and sizes of nets and other
instruments are regulated, also the methods of using them, and the
places where they may be used ; aclose time for mussels and sparling is
enforced, and steam trawling within the territorial waters is abolished.”

One of the bye-laws enforced is the increase of the size of mesh in
trawl-nets from 43 inches to 7 inches, 7.¢., the mesh measured around the
four sides; as demonstrating the need for regulation, it is interesting to
quote again from Mr. Dawson the results of two hauls made with trawls
of only 25 feet between the trawl heads. In these trials a net of 7 inch

78 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

mesh was used, which had a net of 43 inch mesh laced round the cod end
in such a manner that no fish could get into the net of 43 inch mesh
without first passing through the net of 7 inch mesh.

Haul made June 29th, 1894, net down one hour :—

397 plaice, average length, 9 inches.
In the net of 100 dabs, ;
7 inch mesh. ] 16 flounders, “ # 2
1 skate, es ee a broad.
Total. .514

2.515 dabs, oe at

35 young ray, very small

iin dhe ae) a) 710 plaice, average length 6} inches.
41 inch mesh.

Total. .7,260

The above shows that under ordinary circumstances 7,260 small fish
in the one short drag would have escaped through the 7-inch mesh, and
remained to grow larger. As will be seen by the sizes, the fish taken in ~
the 7 inch mesh net were mostly over }-lb., whilst those which passed
through were all under that weight.

““In a second haul, made on July 19th, 1894, the result was as
follows (net down 13 hours) :

23 soles, length in inches 93 to 143

‘In net of 7-inch } 131 plaice, s Se
mesh. | lSkdabs;. =< gs ee S10)
1 skate, “ ‘¢ 10 broad.
Total. .174
6 soles, ‘ a 5 to 8
610 plaice, “ a A
“< Tn net of 44-inch } 323 dabs, of te Aa ag
mesh. - surnen |): % 6
1 whiting, ‘‘ a 6

87 young ray, very small.

, Total. .1,031

The result of the second drag shows that under ordinary circum-
stances out of a total of 1,205 fish, 1,031 which were under 4 oz. in
weight would have passed through the net of 7 inch mesh, and so
escaped, and further, that the 7 inch mesh will take soles much under
the size represented at some of the inquiries made in the district.
Although the proportions as regards number retained in the net of 7 inch
mesh was much smaller than that retained in the net of 43 mesh, it
represented a larger monetary value, owing to the fish being larger and
in better condition.”

Comment on such figures is superflous; they demonstrate conclusively
the need for a thorough local investigation here, with, of course, careful

FISHERY IMPROVEMENT IN JERSEY. 79

regard to special local needs and circumstances, as our coast line is
governed by exceedingly complex conditions. One of the special
duties of the officers of a Fishery Committee is obviously to make a
careful survey of their whole area to determine the spawning grounds
and nurseries, 7.¢., grounds frequented by immature fish, and, when
determined, to take measures to protect such efficiently. Such a ground ~
was discovered on the Lancashire coast opposite Blackpool, and the
utility of such a regulation is demonstrated by quotation of the results
of three typical hauls of a shrimp trawl on this ground, also given by
Mr. Dawson.

November 7th, 1893 :—

5% quarts of shrimps
6,117 flat fish
81 round fish The trawl was fishing
so 30 minutes.
6,198

December 28th, 18985 :—

224 quarts of shrimps

20,772 flat fish

117 round fish The trawl was fishing
f

40 minutes.

20,889

January 2nd, 1894 :—

6 quarts of shrimps
8,356 flat fish
156 round fish The trawl was fishing
—— 45 minutes.
8,512

“The flat fish taken in these hauls comprised soles, plaice, and
dabs; the round fish, whiting, codling and herrings; these were all
immature and undersized, ranging from about 1 to 3 inches in length
and of no use whatever for market. When it is considered that from
70 to 90 boats used to be employed shrimping on that particular ground,
each boat making from four to five hauls per tide, it will not be wondered
at that the Committee closed it, nor can it be denied that such must be of
immense benefit in the protection of under-sized sea-fish.”’

The Scientific Department’s work is of necessity less showy in imme-
diately practical results, though it must be borne in mind that the
labours of this Department are indispensable in arriving at a knowledge
of the factors that have to be understood before the framing of adminis-
trative bye-laws. The general scope of this Department’s work may be
summarised as the investigation of the food and feeding habits of fish,
their spawning habits and early history ; the controlling conditions and
localities of their migrations ; experiments with a view to the introduction |
of oyster and mussel culture or of improved methods; investigation into
the connection between oysters and the transmission of disease, the

50 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

artificial hatching, &c., of sea-fish and lobsters, the giving of free fishery
lectures and demonstrations, the preparation of a fishery exhibition illus-
trative of the methods of fishing and fish food, fish enemies, &c., locally
and abroad.

The cost of all this work is about £2,700 per annum, and the increase
in the value of catches within the Lancashire sea fisheries district in 1895
was £78,761 over the value of the catches of 1891, the year in which the
Committee commenced its labours. From the nature of the case, it is, of
course, impossible to say what part of this increase is due to the efforts
of the Committee; but it can fairly claim, I believe, that such have had
a really considerable effect in the production of this favourable result.

I have gone into the foregoing details at considerable length as the
scheme of work in the district is definite, has been successful, and the
local factors are somewhat analogous to our own.

At the same time, the work of our English Fishery Committees is
at present much behind that of Scotland and of several foreign nations,
in one respect, viz., the establishment of sea-hatcheries for fish,
lobsters, &c. Scotland, the U.S.A., Newfoundland, Canada, and
Norway have all important establishments from which millions of young
are annually turned into the sea, whereas in England the Lancashire
Committee is the only one making definite preparations for the incep-
tion of such work.

To the U.S.A. we owe the inception of marine fish hatchery, as it
was at the Fishing Station at Gloucester (Mass.) in 1878 that the eggs
of the cod, the whiting, and the herring, were successfully hatched.
Norway very quickly hastened to take the matter up, and from the
great hatchery at Flodevigen turns out annually many millions of
young cod. Captain G. M. Dannevig, the greatest expert in this work,
asserts that it is only the effects of this hatchery that prevent the
extinction of a fishery valued at several hundred thousand pounds 2
year. That the Norwegians themselves are convinced of the practical
benefit is best proved by the fact that the yearly grant to the hatchery
has always been made with the greatest willingness, notwithstanding
the meagre financial resources of the nation; when last year an adverse
motion was introduced in their Parliament it was negatived by 114
votes to 11, a conclusive vote of confidence.

The Dunbar hatchery instituted by the fisher Beata for Scotland,
is engaged chiefly in the hatching of plaice. In this work, therefore,
we have naturally greater direct interest than in that of the Norway
establishment, which is concerned most largely with the culture of
codfish. In structure and arrangement the Scottish Fishery Board has
followed strictly the model of the Norwegian hatchery, and consists
essentially of :—

Ist. A pond subject to the rise and fall of the tides, wherein are

FISHERY IMPROVEMENT IN JERSEY. Si

stored a selected stock of adult fish sufficient to provide the quantity
of fertilised eggs required for the purpuses of the hatchery.

2nd. A boiler and pumping room.

3rd. The spawning pond in which the spawners (males and females)
are placed when extrusion of the spawn and milt is about to begin.

4th. The collector, or system of filters necessary for separating and
gathering the floating eggs.

5th. A main Hatchery-room fitted with the Dannevig floating-ege
incubators, capable of dealing efficiently with 56,000,000 eggs of plaice
or with 80,000,000 eggs of the cod, at one time.

The Dannevig apparatus, which is intended for buoyant eggs alone,
consists essentially of a wooden box, 8 feet long, 2 ft. 3 in. broad and
1 foot deep, and divided into two longitudinal compartments by a
partition. Hach compartment is again transversely divided into seven
others, and in each of these (excepting the end ones) a wooden lid-less
box is hinged by one edge to the top of the wooden transverse parti-
tion; the other edge is free, and when water is admitted, rises above |
the level of the water; the bottom of each floating box consists of
hair-cloth and acts as a sieve. To obviate the permanent eddies and
currents caused by the constant course of the inflowimg water, Capt.\
Dannevig invented a beautifully simple arrangement whereby the rythmic
depression of a long leyer bearing transverse bars catching the sides
of the floating boxes, causes the latter to rise and fall several times per
minute; this breaks up the eddies, and ensures an equal distribution of
the eggs through the water. Each box cau accommodate half a million
eggs of the cod, or 300,000 eggs of the plaice; each apparatus contains
10 of these boxes. A Dannevig incubator can thus deal with five millions
_ of cod eggs simultaneously. .

The output of fry fiom this hatehery in 1895 was: — Plaice,
38,615,000 ; cod, 2,760,000; turbot, 3,800,000 ; miscellaneous, 1,050,000 ;
a grand total of 46,225,000.

It is worthy of note that the authorities consider the services rendered
by the Fishery Board for Scotland fully justify the indefinite continuance
of the grant of £23,000 per annum.

In Newfoundland, the great work of hatchery effected at Dildo Island
in Trinity Bay, and at various outlying points along the coast, has also
special interest for us in Jersey, for while the hatching of cod fry is the
chief item in the official programme (221,500,000 being set free in 1894),
it is here we have to turn as to the fountain head for information upon
the artificial hatching of lobsters. Whereas the cod fry are all hatched
out at Dildo, the vast majority of the lobsters are hatched out in
numerous small floating wooden incubators stationed up and down the
coast. In these boxes the eggs are placed after being stripped from the

82 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

berried females. ‘This obviates the certain destruction of the eggs as
they would otherwise pass to the cannery along with the parent. During
five years, dating from 1890, the almost incredible number of
2,340,657,000 lobster fry have been liberated from these floating
incubators alone; about 645 millions of cod, and about 383 millions of
lobsters were in addition set free from the main hatchery. The total
annual expense of the Newfoundland establishment is from £1,000 to
£1,200 annually, out of which the Superintendent draws a salary of
£600.

Canada does similar work, dating from 1891, at Bay View, Picton
County, Nova Scotia, and is likewise largely concerned with the hatching
of lobsters. \

In the U.S.A. two chief marine hatching stations are in operation,
viz, Gloucester (Mass.) and Wood’s Holl; from the latter alone were
hatehed during 1895 seventy millions of cod and whiting fry, two
millions of plaice fry and seventy-five millions of lobster larvee, while at
several sub-stations vast quantities of shad fry (Clupea sapidissima) were
hatched and set free.

Turning to other forms of practical fishery work, we find that the
Congested Districts Board of Ireland are planting the coasts of Galway
and Donegal with large and efficient fishing boats, built and furnished
with gear after the most approved Scottish pattern, to replace the flimsy
canvas and wicker coracles and curraghs still in use by the impoverished
fishers of the districts. Picked fishermen from the Fraserburgh district
are provided by the Board to introduce and teach the fishing methods as
practised successfully on the Aberdeenshire coast, and the Irish fishers
are found very apt to learn and quite alive to the advantages of this
training. Nor is this all; the Board lends money on the recommenda-
tions of the Fishery Inspectors for the purchase of improved boats and
gear; up to the 31st March, 1896, £9,515 had been so issued.

The Fishery Commissioners for Ireland have pursued the same plan
since 1891, for districts outside the jurisdiction of the Congested Districts
Board, and up to 31st Dec., 1896, had issued £14,843 in loans to
fishermen, whereof £6,782 has already been repaid in capital and
interest. Considering the largeness of the figures, and the character of
the people lent to, it is extremely satisfactory to learn that the entire
arrears for capital amount to the comparatively trifling sum of £160.

Another striking and very practical instance of the energy developed
by governing bodies at the present day in favour of improvement in
fisheries is the step taken this year by the Cape Government in obtaining
a first-class steam trawler to place at the disposal of their scientific staff.
The dimensions of this vessel, the ‘‘ Pieter Faure,” are 110ft. by 21ft., and
she is fitted with triple expansion engines of the highest class. Her first
and primary duty is to explore for fishing grounds off the coast of Cape

FISHERY IMPROVEMENT IN JERSEY. 83

Colony, and to demonstrate practically te the capitalists and fishermen of
the Colony what undeveloped resources are ready to their hand if they
will but equip proper vessels—the steam trawler being unknown there at
present, as a consequence of want of knowledge of any suitably extensive
fishing banks. According to recent advices, the results attained have
surpassed the most sanguine anticipations, as immense catches of fine
marketable fish have been made in many of the trial hauls.

Acclimatisation while of the greatest success with regard to fresh
water fish, has only been tried with sea-fish upon anything approaching
a commercial scale by the United States. The experiment was begun
26 years ago, when 12,000 shad fry / Clupea sapidissima) brought from the
Atlantic Seaboard, were liberated at the mouth of Sacramento River,
on the Pacific Coast. During the ensuing 15 years 1,519,000 Atlantic
fry were set free at various points on the same coast. The result has
been truly marvellous and one about the success of which there can be
no question; thus in 1892, the fishery upon the West coast was estimated
at 700,000lbs., and this, too, without special effort being made to
capture ; most was taken unintentionally in salmon nets and otherwise.
So abundant indeed were the fish, that the price there was lower than
upou the Atlantic coast. Besides the shad, the United States Fishery
Commission has introduced the Atlantic striped bass (Roccus lineatus ) into
the Pacific. In 1879 about 150 individuals were freed at the mouth of
the Sacramento River, and three years later another batch of 300 were
liberated at the same spot. The result of these two small introductions
is that a new and growing industry has developed ; so early as 1892 it
produced 43,000lbs. of fish.

As a concluding item in this all too brief and inperfect survey, we
have to note that two years ago the States of Guernsey appropriated £100
for experiments in Lobster hatching and another £140 this year, with a
view to increase the supply.of this crustacean. Last year was tentative
and an extremely small number were set free. This year at the
beginning of July, five of the Nielson floating-incubators were in
operation at Grand Havre, two at Perelle Bay and one at St. Sampson’s.

Parr 3.—Scope and programme of the Investigation and Haperiments
requisite locally.
Such work falls naturally into three divisions :—
1. Investigation.
2. Experiment.
3. Education and the supply of information.
1.— Investigation.
a. It is important that an exhaustive investigation of the methods
of fishing now pursued upon the Jersey coast, should first be undertaken,

84 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

with a view to acquire data whereby we may learn what methods
are detrimental, together with the probable remedies required.
Especially should this investigation be directed to the merits and
demerits of chervin fishing, set-nets, draw-nets, and raking for sand-
eels—questions to which Deputy E. B. Renouf has already drawn the
attention of our Legislature, thereby earning the sincere gratitude of
our fishermen.

b. If alteration be needed-in the size of mesh in any form of net
at present in use.

e. To what extent and upon what lines should low-water shore-
fishing be restricted. This is very probably an important item, as
the wide stretch of shore from high to low-water marks forms an
important resort for immature crabs, lobsters, etc., to say nothing of
the scope it offers for the future culture of shell-fish.

d. Over what animals (fishes and baits) should the protection of
close-time be conferred, and what the duration of the same.

e. The dates at which spawning occurs locally in all our food
fishes and baits. This obviously must be determined with exactitude
prior to the institution of close-times.

f. To define the best size below which the capture and sale of certain
fishes should be interdicted.

g. To ascertain the exact nature of the food of our common local
fishes, the object being to take measures, if possible, to increase the
quantity of such supply.

h. To discover and define the extent of local spawning grounds.

?. Should certain areas of the inshore waters be set apart as closed
erounds where fishing should be prohibited; these to serve as nurseries
or shelter grounds for immature fish.

j. To ascertain if the amount of destruction of young fish by sea
gulls is sufficiently serious as to call for the amendment of existing laws
protecting such birds.

k. As to the extent of French “poaching” within the three mile
limit, and the steps to be taken to prevent this.

Z <A survey of the whole coast to ascertain what localities are
suitable for the culture of such useful shell-fish as cockles, clams, and
mussels.

m. ‘To re-investigate in the light of modern knowledge the causes of
the decay of the oyster beds off Gorey, and to devise means for their
restoration.

n. What restrictions, if any, should be placed upon the sale of
‘‘ berried ”’ lobsters.

2.—Haperiments.

The chief experiments that suggest themselves as likely to have

practical and useful outcome may be enumerated as follows :—

FISHERY IMPROVEMENT IN JERSEY. 85

a. To ascertain to what extent the free-swimming larve of lobsters
are strictly surface swimmers.

6. To ascertain by means of ‘‘ drifters”? the mean or usual drift of
our surface currents under definite conditions of wind. This with a view
to learn the probable drift of pelagic fry were they to be hatched in, and
liberated from, an incubating station on the coast.

c. To ascertain the course of the migrations of our local food fishes
and the determining causes. Although this is difficult work, the
experience of Dr. Wemyss Fulton, upon the coast of Scotland, is that in
regard to certain fish, such as plaice, this knowledge can be gained by
the marking of the fish by means of metal discs each impressed with a
consecutive number and securely fastened to the fish, the fish being
subsequently liberated. Rewards are then offered for the capture of
such marked individuals. In this way Dr. Fulton has found that there
is a general northward movement of plaice upon the east coast of Scot-
land. More than 10 per cent. of the marked plaice—over 1,000—have
been recovered, a very satisfactory percentage.

d. To adopt or to discover a cheap means for the preservation of
bait for lengthy periods and to elaborate a scheme for its storage in
sufficient quantities.

e The introduction and culture of a better class ‘‘ red-cat’’ bait
worm, such as the giant ‘‘creeper’”’ (Nereis virens) of the Irish Sea
fishermen.

f. The introduction of the culture of the cockle, a highly lucrative
industry wherever pursued. In England and in France it gives employ-
ment to thousands of fishermen.

g. The introduction of mussel culture. If this were successful it
would tend to lessen the disability under which our local fishermen so
‘frequently labour on account of scarcity of bait. On the Scottish coast
the mussel is the most important of the baits used by the liners.

#. The re-introduction of the ormer (Halotzs) on an extensive scale.

3.—Hducation and Information Bureau.

Such practical work as is detailed above should, however, be supple-
mented by means of :—

a. Free lectures to fishermen upon fishery problems, to enable them
to follow closely the development of fishery methods elsewhere. Demon-
strations upon methods of fishing and of shell-fish cultivation in other
lands should also be included, together with some instruction in the
elementary facts in the life-histories and habits of our common fishes.

6. Prizes to fishermen for the encouragement of suitable objects.

c. The establishment of a Fisheries Collection, to illustrate by actual
specimens and by models, drawings and the like, the varied methods of
fishing pursued abroad and at home, preserved specimens of the animals

86 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY

injurious to fishes; a series to illustrate the nature and variety of the
food of each of our food fishes; samples of the ‘‘ bottoms” around
Jersey, &e., &e.

Such an exhibition, open free to fishermen, would be of very great
educational value to them in their calling, especially as showing them
what is being done elsewhere by methods different from their own.

3. The establishment of an Information Bureau, which, among other
uses, could, by means of a simple system of corresponding agents in a
few of the home and continental fish centres, advise fishermen as to the
supplies of bait obtainable elsewhere in times of bait scarcity here, and,
if desired, to take measures to put the fishers here in communication
with bait sellers abroad. Other useful work would consist in the
collection and tabulation of loeal fishery statistics. |

Part 4.—Summary of the Fishery Laws relating to Jersey waters ;

their inadequacy to meet present requirements.

Having thus taken note of the chief lines upon which investigation
_ and experiment should proceed, it behoves us to inquire into the pro-
visions of the Fishery Laws already existing in the statute book.

During the present century, three Fishery Laws have been enacted
by the States of Jersey, while four Acts of the lnperial Parliament have
been registered here, and have accordingly full effect in this Island.
They may be summarised as follows :—

1, The regulations with regard to the oyster fishery off Gorey, made
during the preceding century, having failed in their object of safe-
guarding the beds, the States, in 1841, passed a fresh law re-regulating
the details of the fishery with great precision; and the Harbour Master
of Mont Orgueil was appointed Inspector of the fishery to ensure the due
observance of the various provisions. This law, however, proved
equally inadequate to prevent the practical extinction of the industry, as
it contained no provision for preserving a reserve sufficient to keep up
the supply of spat. Between September Ist and May 3lst, fishing on
the outer beds was permitted to all comers of British nationality and as
many oysters might be removed as they were able to dredge. The
height of this transitory prosperity was between 1840 and 1850, when
250 boats were not uncommonly employed simultaneously. The average
catch was enormous; about 40 tubs each, and when we learn that a tub
contained from 800 to 400 oysters, giving a catch of 12,000 to 16,000
oysters per boat per day we cannot wonder at the rapid exhaustion of
the beds. KHvyen these catches were frequently exceeded; thus Mr. J.
Perchard, of Gorey, one of the oldest dredgermen living in Jersey, has
informed me that his boat on one occasion took 120 tubs, the equivalent
of 36,000 oysters at a low estimate. Again, I have record of another

FISHERY IMPROVEMENT IN JERSEY. 87

boat having taken, about 1845, 327 tubs in three consecutive trips.
The natural consequence of this course of wholesale and disgracefully
improvident exploitation of the beds is seen in the fact that this great
industry has dwindled to such an extent as to be represented in the
present year (1897) by a single small dredging boat taking on an
average not more than 200 to 300 oysters per day.

2. In 1843 an Act of the Imperial Parliament was registered in
J ersey minutely regulating fishing methods, even to specifying the size
of the mesh in the chief forms of nets then in general use. Thus the
centre net of trammels had to have a mesh measuring 2in. along each
side, and many other items of a like character. This law, most useful in
many of its provisions, was repealed by the Act of 1868.

3. In 1862, the States passed a local law—subsequently modified in
1869 and 1886—the main provisions now in force being :—

a. That all nets, excepting seines or draw-nets for the capture of
smelts (gras-dos/, and sand-eels, shall have a mesh measuring at least
14 in. along each side, being the equivalent to what the fishermen now
call a 3-in. mesh.

6. That the use is forbidden of draw-nets or other nets employed to
draw fish to shore, in the bays of St. Aubin, St. Brelade, Grouville, and
St. Clement.

c. That a minimum size of 9 inches in length is prescribed for
lobsters and plaice; the capture and sale of smaller-sized fish being
prohibited under penalty.

This law so far as it goes, is most excellent, but has been treated as
non-existent by many people, as no adequate machinery exists to enforce
its respect.

4, In 1869, “‘The Sea Fisheries Act, 1868,” was registered in Jersey
whereby numerous prior restrictions and regulations of sea-fishing con-
tained in the Act of 1843 were annulled—and no provision was made for
their replacement by others.

This Act marks the climax of a period of reactionary thought in
fishery matters, now all but universally condemned. This repeal of
former restrictions was due to the misconception, entertained at that
date by even the highest authorities, that the resources of the sea are
inexhaustible ; the enormous numbers and fecundity of the edible fishes
and the vast extent of the waters round our coasts, appealed so vividly
to the minds of the Commissioners appointed by Government to investi-
gate, that they agreed that fishermen might fish when, where and how
they liked, quite without restriction. The fishermen themselves thought
differently, but arrayed against them were Professor Huxley and a band
of highly talented and earnest men of authority, such for example as
Lyon Playfair, Shaw Lefevre, Frank Buckland, and Spencer Walpole.
The weight of authority prevailed, and fishermen were, in effect, told to

$8 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

go and eatch as much fish where and how they liked, and to take no
heed for the morrow.

Since 1868, statistics of fishery results have been kept with considerable
exactitude, and the conclusion derived from a careful examination of the
yearly differences in yield is that over the whole extent of the British
sea-fishery area, the old fishing grounds are steadily becoming depopu-
lated, and that to keep up the supply our fishers have to go further
afield and the endeavour is constant to discover new grounds to replace
the exhausted ones lying nearer home.

Hence, from the steady accumulation of such observations, the
irresistible conclusion has been driven home to those watching the
development of affairs, that the Act of 1868 has proved harmful. As a
consequence of this feeling, Parliament, a few years ago, gave permission
to the Maritime County Councils to form Fisheries Committees, part of
whose duties it should be to pass bye-laws {under sanction of the Board
of Trade) reguiating and restricting, where necessary, their loeal in-shore
fisheries.

Deep-sea fishing still awaits legislative control, international agree-
ment being difficult to effect.

5. The next Act concerning our fisheries in Jersey, is ‘‘ The Wisheries
(Oyster, Crab and Lobster) Act, 1877.” The provisions which concern
us are that by it are forbidden the capture, exposure, sale or purchase of
soft erabs, 7.¢., those that have reeently cast their shells; of any edible
erab less than 44 in. across the broadest part of the back; lastly of
‘‘berried”” erabs. ‘This law has in no wise been enforeed in Jersey, and
indeed the provision it makes as to the minimum size for erabs is absurd,
for this takes no account of our. local custom to consider several crabs
edible which are not so considered in England. For example the
eommon shore crab (Caremus menas}) and the ‘“ Lady-erab” /Portunus
puber) are both eaten here, and even when adult these species rarely
reach the size limit given in the English Act.

6. Following this is a most excellent and well-eonsidered measure,
passed by the States in 1882 to facilitate the establishment of oyster
parks along the littoral of our Island. It is under the gis of this law
that the one bright spot in our Island fishery-work has arisen, in the
form of the formation of the Jersey Oyster Culture Co., Ltd., whose parks
at Green Island are models of what such establishments should be.

7. The last measure of all, is one registered here in 1884, but as this
relates largely to the provisions of the International Convention
concerning the Fisheries in the North Sea and has no importance loeally,
we need not detail its enactments.

Summarizing the effects of the fore-gomg facts, we find that the
Oyster Act of 1841 was insufficient to protect the industry in question,
the result being the destruction of the beds; the useful Act of 1843 has

FISHERY IMPROVEMENT IN JERSEY. 89

been annulled; the Act of 1869 is worse than useless; that of 1877 is not
applicable to our local needs, and isin some respects anomalous; the law
of 1882 upon the establishment of oyster parks concerns the capitalist
rather than the fishermen; that of 1884 has little or no local bearing.

We are thus left with the local Act of 1862, which so far as it goes,
contains sound and useful provisions. Unfortunately we have no efficient
means in existence to ensure due respect for its enactments; its scope,
also, is much too limited when viewed in the light of recent research and
knowledge.

The conclusion to be drawn is that our laws are quite inadequate to
meet present requirements, while if satisfactory new ones be framed it is
absolutely essential that there be made, concurrently, efficient provision
for enforcement, otherwise, as at present and in times past, such laws
will fail to compass their object and for all practical purposes will be
treated by those desirous of doing so, as non-existent.

Let us rely no longer upon the sordid greed of the informer as the
chief instrument for the detection of the law-breaker; let us rather
delegate police duty to specially appointed men, who, working amicably
with the better class of our fishermen, will honestly and impartially
carry out their duty.

Part 5.—Forecast of the probable outcome of an adequate local
fishery investigation.

The role of the prophet is notoriously a difficult one. Still, from the
extent of my personal knowledge of local factors, I feel perfectly confi-
dent that the majority of the lines of reform indicated in the following
sentences will be the correct ones to follow in case the authorities see
their way to delegate a committee with power to make extensive investi-
gations and experiments.

1. Restrictions upon the use of set-nets and draw-nets would hinder
much unnecessary destruction of immature fish. The mesh of these
nets, in case entire suppression be not enforced, should measure not less
than 2 ins. along each side. With this increase in the mesh it might be
possible still to permit the use of these nets during say the last three,
and first two months of the year, and even during this period the use of
draw-nets by night would probably have to be interdicted. Such
restrictions would be welcomed by fishermen themselves, for they seldom
abuse these modes of fishing. The real offenders are chiefly men who
work these nets merely to gratify their instinct for sport and amusement,
or from the wish to make a little extra pocket-money. Indeed, I have
heard very definite whispers that members of the Honorary Police, men
pledged to enforce the law, are to be found in the ranks of these illegal
fishers.

90 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

I have it on good authority that over 30 draw nets were in use in St.
Aubin’s Bay one dark night recently, and I have myself seen net after
net along the bay in active operation, hauling to shore quantities of small
whiting, bass, and plaice, too small for useful food.

2. Chervin fishing calls for some regulation. So far as I know, it
entails practically no destruction of fish fry, the contents of the net
being a pure gathering of Myside, a family of tiny shrimp-like creatures
of no known use as human food, fished for solely to furnish a ground-
bait in rod-fishing for mullet. They however constitute an important
food supply to many species of our local fishes. Thus whiting, mullet,
gurnard, young rays and other fishes are attracted inshore by the
abundanee of these Myside, and their numbers around our coast depend
to a certain extent upon the abundance of this food supply. A few days
ago I counted nine men netting for chervin in St. Aubin’s Bay, and as
many as 30 have been known to be fishing during the same night, while
eighteen is an ordinary number. The majority of these men are farmers
and their servants to whom the discontinuance of this fishing would be
no special loss. To a few, probably about eight in number, such would,
however, be a distinet hardship—men who have worked at it as their
chief source of livelihood for years. 'These men may therefore be said to
have a certain prescriptive interest, and while chervin-fishery should
eventually be prohibited, these men might be granted non-transferable
licences, to expire with their diseontinuance of the fishing. In this way
the fishery would be extinguished without inflicting hardships upon
any one. The export of chervin should also be prohibited.

3. Close times. Breaming has been continuously going from bad to
worse of late years. When these fish (Cantharus griseus) come off our
coasts, their spawning period is nigh—and it is probable that the
continuous decrease in their numbers is due to too large a proportion of
the spawners being captured. Hence a close time of, say a fortnight, at
some period of the breaming season would be likely to effect an
improvement in succeeding years by permitting the escape of spawners
sufficiently numerous to maintain the race in undiminished numbers.

A close time for the “ red-cat ’’? worm (Nereis) during its breeding
season would be certain of adoption, while in view of the introduc-
tion of the cultivation of the cockle and the mussel, close times for such
should be instituted.

4, The interdiction of low-water or littoral hunting for erabs, lobsters
and the like, over certain areas at least, would be productive of great
good. Thousands upon thousands of undersized crustaceans are taken
there, and this tends largely towards a poverty of adults in the deeper
water. ‘To remedy this, the littoral should be carefully protected as a
nursery and feeding ground for these crustaceans.

5. Restrictions upon the capture and sale of berried lobsters should

FISHERY IMPROVEMENT IN JERSEY. Of

be enacted, but if lobster incubation be feasible upon this coast, as I
think now it is, the sale of such individuals would be permissible if the
“coral ” or eggs were given by the fishermen to the official in charge of
the incubators.

6. The re-establishment of a profitable oyster industry is, in my
opinion, by no means an illusory dream. A certain number of oysters
are still present upon the beds, and if quantities of fresh, well-cleaned
‘“ eulch,” ¢.e. empty shells whereto the swimming spat may adhere, were
to be thrown lavishly over the beds, at the beginning of the spawning
period, I believe a good fall of spat would be secured under ordinary
favourable conditions. Of course it would be necessary to interdict all
dredging and trawling over such grounds for some years, with
resumption only under very strict regulations. The beds are too greatly
exhausted to recover if left to themselves, and a partial cultivation on the
lines I indicate furnishes the only alternative.

In the event of the success of this treatment, with a little energy the
fishermen themselves, by the exercise of a certain amount of co-operation,
should be fully capable of caring for the beds, or at least of a portion of
them.

Under such circumstances, those fishermen assuming such duties
should have ample guarantee against any infringement of their rights.
Either in addition to or in substitution of such oyster-farming, our fishers
might be granted small areas of sea-bottom in shallow inshore waters,
where spat might be laid down to fatten. The expense is a bagatelle ;
the only trouble would arise from poaching, and this is capable of
solution. te

7. By the judicious ‘“ planting” of a moderate quantity of imported
_cockles, in a properly protected area of one of our sandy bays, a cockle
industry of considerable value is surely capable of development.

8. In regard to another of the minor fishing industries, to wit, the
- culture of mussels, our island offers considerable scope. Here again it
would be necessary to import a quantity of mussels, probably both seed
mussels and adults, to be judiciously ‘‘planted”’ in selected and protected
localities. In France much of the mussel cultivation is upon the Buchét
system, which consists of long lines of piles closely interlaced with
osiers, and is there extremely lucrative. The foreshore of one small
village near La Rochelle is said to yield a sum of £50,000 to £70,000
per annum from mussel cultivation alone. After a careful estimate of
the cost of such piles and the necessary osier, I find, however, that it is,
in Jersey, so much higher than in France, that such a system of
cultivation would not be profitable here. ‘‘Bed-culture” would be
preferable in Jersey, being the form of culture practised in Scotland, a
land where the mussel forms the staple bait of the fishermen.

9. The question of profitable fish-hatching depends, locally, almost

92 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

entirely upon the general set of the currents, and no inference of any
real value can be deduced until a long and severe series of experiments
with “ drifters ” be instituted, on the same tines as those adopted by the
Deutsche Seewarte and the U.S. Hydrographical Survey in working out
the Atlantic currents, by Prince Albert of Monaco in following the
course of the Gulf Stream, and nearer home by the Fishery Board for
Scotland. The drifters in use by the latter body are small thick glass
bottles of loz. capacity, each containing a card with a request in English,
German and Norwegian that the finder post particulars of the recovery
of the bottle to the office of the Board in Edinburgh. These bottles are
tested in a tub of water before being set free, and by means of a piece of
lead wire twisted round the neck, they float mouth downwards, showing
no surface above the water to catch the wind, attention to the latter
point being very important. Wooden slips bearing the instructions
tacked on and weighted at one end, so as to float upright, have also been
used, but are found to be less satisfactory than the bottles, as the coating
of paraffin wax necessary to prevent the soaking of the ecard and of the
wood, is very liable to abrasion.

Various indications which have come to my knowledge ineline me to
entertain strong hope that the set of our currents, under the prevailing
condition of 8.W. winds, is such that any floating objects set free at —
definite times of the tide are earried backwards and forwards and even
round and round our island, thus rendering economically feasible the
liberation of fry from a hatchery on our coast. The indications I refer
to are (@) the general belief held by fishermen that objects floating at
the mercy of the tide during prevalence of certain winds perform the
entire circuit of the island, reappearing at the place where they were
first seen; and (6) the fact that in September, 1895, out of fourteen cases
containing brood oysters which broke loose from the oyster beds at
Green Island during a gale from the 8.W., thirteen were recovered on
this coast; all began by travelling to the eastward, nine were recovered
at La Rocque, one or two were sighted off the north-east coast, and one
off l’EKtacq, the latter travelling southward ; two were picked up at the
Corbiére, while the last two were found at the Sambue, not far from the
starting point, having either travelled to and fro, or having made the
complete circuit of the island. The longest afloat of the thirteen
recovered was so for twenty-one days.

As regards improved bait supplies, I believe that great help could be
accorded by a local Fishery Committee to the fishermen at little or no
expense, in several ways. My own favourite idea is the initiation of a
dry-air refrigerator, in which supplies of bait aequired here, or imported
from abroad, would be stored—until such time as needed—when the
fishermen would be allowed to purchase it at a price just sufficient to
cover actual expenses. No greater boon could be granted to our fish-

FISHERY IMPROVEMENT IN JERSEY. 93

ermen, and it is one, too, that would be virtually self-supporting. For
example, squid is often common in France when none is to be had here—
and even if a French supply were to fail, the U.S.A. can furnish unlimited
quantities, which could be shipped to Southampton or Bristol in one
of the refrigerating chambers of a liner bound for one or other of these
ports.

Such a programme as I have outlined above would necessarily take
several years to work through. However, I see no reason to doubt that
one year’s work would be sufficient to accumulate the information
necessary to settle the majority of the points listed under the head of
“‘Tnvestigations.”” Such information would then be available for the
framing of well-considered bye-laws, regulating the existing fisheries.
Some of the simpler experiments might also be worked upon during such
initial year, together with the formation of a Fisheries’ collection, the
delivery of lectures, and other educational matters.

The second year should be occupied with the due enforcement of the
new bye-laws; with the carrying out of further investigations ; with the
prosecution of the more important experiments; and with lobster
hatching in floating incubators on a large scale, should investigation
have shown that such may be done here with advantage. The inception
of a small Bait-store might also be feasible during the second year.

The hatching of plaice fry—if considered desirable—together with an
attempt at restocking the Gorey oyster beds by inducing a fresh and
large fall of spat, might form the chief new items in the third year’s
work, ‘Thereafter the steady development of these various undertakings
and the consistent enforcement of the provisions of the law are chiefly
what would be requisite, though new lines of investigation would
undoubtedly be suggested from time to time. The circumstances of the
hour would, of course, largely affect the order of this programme, as it
is impossible to guage accurately the respective durations of the various
‘investigations and experiments.

The cost of this work is difficult to assess—so much depends upon
how many items are attempted in each year, but bearing in mind
favourable local circumstances, I believe a grant of £150 would be
sufficient, by the exercise of stricL economy, to meet the expenses of the
initial year’s working, inclusive of salaries, boat hire, and minor items.
The expenses of succeeding years would depend still more upon the
character of the work attempted; probably £30 extra would be amply
sufficient during the second year.

These figures are, I know, likely to be criticised by outside authorities
as absurdly low and quite inadequate to the great range of work
sketched out.

In explanation of this, I wish to state that such critics must
remember that we already have in Jersey a Biological Station, which

94. JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

although it has never received a single penny of subsidy from any source,
is now in full working order and provided with laboratories, pumping
machinery, tanks and other appliances suitable for carrying out fishery
experiments, and that if the States of Jersey think fit to take up the
question of Fishery Reform in a broad spirit, I shall be willing to place
the whole resourees of my Biological Station at their disposal, free of
charge, for experimental work, during the first year at least, upon no
other condition except of recoupment of the bare extra expenses thereby
entailed. Without such facilities, local fishery investigation would be
seriously handieapped and its value largely reduced, while if specially
provided as has been requisite elsewhere, an initial expenditure of
several hundreds of pounds would have to be ineurred. Such expense
can be avoided in Jersey.

Again, if such fishery reform be decided upon, I would gladly devote
the Museum Room of the Station to the purposes of a Fisheries Collection,
getting together and preparing at my own sole espense the necessary
exhibits, which moreover I would willingly throw open to fishermen free
of charge.

This statement will therefore explain the obvious lowness of my
estimate, which of course is contingent upon the continuanee of my
residence in Jersey, as otherwise the Biological Station would be devoted
to other uses. In the latter case, if the programme of fishery work
which I have sketched, were earried out, the estimate of cost would
require to be very considerably augmented.

In closing this imperfect sketeh of loeal fishery problems, I wish to
express my very grateful thanks to Dr. F. Wemyss Fulton, Scientific
Superintendent to the Fishery Board for Seotland; to Mr. Harald
Dannevig, Superintendent of the Dunbar Hatchery; to Dr. Canu,
Director of the Station Agricole at Boulogne; and to Mr. Robert A.
Dawson, Superintendent to the Lancashire Sea Fisheries Committee, for
the more than ordinary kindness with which they have rendered me
invaluable assistance in the preparation of this paper.

REPORT ON THE
PLANKTON COPEPODA OF THE CHANNEL ISLANDS.

BY ISAAC CGC. THOMPSON, F.L.S.

A COLLECTION of thirty-nine bottles containing plankton, taken by
tow-net at various dates between 1887 and 1897 about Jersey and
Guernsey was lately placed in my hands for examination, by Mr. Hornell,
the Director of the Jersey Biological Station. With the exception of
one bottle marked December 7th (1892) all the material was taken
between the months of February and September. By far the largest
proportion of the material is Copepoda, with a profusion of Nauplii in
those bottles collected during early Spring. Amphipoda, Cumacez,
Appendicularie, Mysidee, Sagitte, &c., occur plentifully. It is with
the Copepoda alone, however, that this report has to do. Thirty-one
Species are represented in the collection, as follows :—

Family :—CaLaNIp&.
i. Calanus finmarchicus, Gunn.

This species, so commonly distributed throughout our seas,
was present in about 25 per cent. of the bottles, but in none very
abundantly, with the exception of that collected in December. As
the chief food of the Greenland whale it is found profusely distri-

buted in the Arctic seas. A parasite of the Calanus, Microniscus

calam, G. O. Sars, was found attached to one of the specimens.
2. Caulanus propinguus, Brady.

Qne specimen of this rarer species was taken in St. Aubin’s
Bay, Jersey, in April.

3. Pseudocalanes elongatus, Baird.

Probably the commonest of British Copepoda. It occurs in all
the gatherings plentifully.

4. Acarive clausi, Giesbrecht.

Almost as plentiful as the last species.
Acartia discaudata, Giesbrecht.

A few specimens were taken in July, in St. Aubin’s Bay, Jersey.
It is easily distinguished from the previous species (4. clausii) by
its short, rounded caudal stylets.
6. Zemore lengicornas, Mill.

A very common British species, plentiful in nearly ab the
bottles, but rarely found except in British seas.

7. Iscas clavipes, Boeck.

or

This easily recognizable species oceurs sparingly in several of

96

10.

HIE

12.

13.

JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY

the gatherings. Though generally distributed throughout British
seas it is rarely found in quantity.
Centropages hamatus, Lill}.

Commonly distributed throughout the district.
Centropages typicus, Kr.

A few specimens were found in two of the gatherings taken in
St. Aubin’s Bay in July and August. It is easily distinguished
from C. hamatus by the presence of three toothed spines on the
anterior antennee, and by the much finer character of the serrations
on the terminal spines of the swimming feet.
Metridia armata, Boeck.

An open sea species, distinguishable by the leaf-like termina -
tions to the swimming feet. It was found very sparingly in three
gatherings from St. Aubin’s Bay.

Family : — Canpacip2.
Candace pectinata, Brady.

One specimen only of this very striking and easily recognizable
species was found in a gathering marked Jersey, April 4th, 1894, no
precise locality being given. It was first found by Drs. Brady and
Robertson at a depth of 40 fathoms, off the Scilly Islands, and I
have on several oceasions taken it very sparingly on the West coast
of Scotland, and have more recently received it from Valentia,
Ireland. Some years ago I took it very plentifully about the
Canary Islands, and it seems probable that it comes to our westerly
and southern shores through the influence of the warm North
Atlantic drift. The deep brown colour of the terminations of the
swimming feet and of its spines and antennee render it very
conspicuous.

Family :—PontTELLIDE.
Labidocera wollastont, Lubbock.

This species, which was originally reported by Lubbock, from
Weymouth, in 1857, occurs sparingly in six gatherings taken in St.
Aubin’s Bay, Jersey. Though apparently nowhere common, I have
on several occasions taken it in Liverpool Bay, and it has been
reported from Heligoland by Claus, and by Canu from Wimereux.

Anomalocera patersont, Temp.

This species, one of the largest and the most beautifully coloured
of British Copepoda, occurs sparingly on three occasions, taken off
Gréve d’Azette and in St. Aubin’s Bay. It sometimes occurs in

enormous shoals round our coasts, but appears to be nowhere
generally common. .

id.

15.

27.
28.
29.

PLANKTON COPHPODA OF THE CHANNEL ISLANDS. Q7

Parapontella brevicornis, Lubbock.

Generally present throughout the collection, often in great
abundance.

Family :—Cyciopip™.

Cyclopina litteralis, Brady.

This species, generally distributed round British coasts, usually
taken near to shore or amongst Algze, occurred sparingly in one of
the gatherings only, taken off Gréve d’Azette.

Family :—Harpacricipa&.

. Delavalia refleca, Brady and Robertson.

Dactylopus tisbordes, Claus.

. Thatestris claus, Norman.

. Thatestris longimana, Claus.

. Harpacticus chelifer, Mill.

. Harpacticus flecus, Brady and Robertson.
. Zaus spinatus, Goodsir.

. Alteutha depressa, Baird.

. Alteutha interrupta, Goodsir.

. Ldya furcata, Baird.

. Scutedlidium tisbordes, Claus.

The above eleven species of the large family Harpacticide,
although free swimmers at times and usually found near to shore,
often in rock pools, are usually classed as semi-parasitic. In
all of them the anterior antennze are of small size, the mandibles
and foot jaws being generally large and strong. Their presence in
the tow-net is but small indication of their distribution, many of
them doubtless being exceedingly common among the rock pools and
in the littoral zone. Only isolated specimens occured throughout the
collection.

Family :—Monsrrinuip@.

Great interest attaches to this family through the recent
important discovery of Prof. Giard, of Paris, and confirmed by M.
Malaquin, that the early stages of one or more species of this group
are spent parasitically in the body cavity of certain worms. (Seo
Comptes rendus, 16 Novembre, 1896, and 21 Décembre, 1896, and
11 Janvier, 1897.)

Two species of cach of the two genera Thaumaleus and
Monstrilla comprised in the family Monstrillide appear to be not
uncommon about the Channel Islands, viz. :

Thaumaleus claparedi, Giesbrecht.
Thaumaleus thompsoni, Giesbrecht.
Monstrilla grandis, Giesbrecht.

98 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.
30. Monstrilla angliea, Lubbock.

All appear to be about equally common, or rather uncommon,
for with the exception of a remarkable gathering taken in St. Aubin’s
Bay, at 9 p.m., on July 19th, 1897, when several dozen speeimens of
T. thompsoni oceur, a few specimens only of it and the other species
were present on only two or three oceasions, and during the summer
months. '

An interesting article upon Jonstrilla anglica, by Mr. J.
Hornell, appeared in Vol. I., part 2, page 42, of the present Journal.

; Family :—SappHirinip&. .
31. Lichomolgus fucicolus, Brady.

One specimen only of this semi-parasitic species was found in
an evening gathering from St. Aubin’s Bay.

In conclusion, while a few species are absent which might have been
expected to be present in an English Channel eollection, it is probable
that the above enumerated list is a fair representation of the free
swimming Copepoda of the district. Doubtless any specialist devoting
himself to their systematie eolleetion eonseeutively, might eonsiderably
add to the number, and deduce valuable information as to their habits,
and bearing on our supply of food fishes, and the causes which lead to
the appearance of particular species at varying or definite periods.

The large number of sedentary species of Copepoda living at all depths
on the sea bottom, and readily colleeted by careful washing from dredged
material are not here alluded to, as also are not ineluded the many
highly organized forms as well as curiously degenerate species of
parasitic Copepoda, which are found attached to the gills, scales or other
parts of most fishes.

Each of these interesting classes might at a future time furnish
material for special reports as distinctly different branches of the subject,
and both capable of being well studied at the Channel Islands.

99

ON A CANCER PAGURUS WITH SUPERNUMERARY
CHELZ.
BY L. A. BORRADAILE, M.A.

(Lecturer in Natural Sciences at Selwyn College, Cambridge).

By the courtesy of Mr. J. Hornell, Director ef the Jersey Marine
Biological Station, I am permitted to describe a remarkable specimen in
the possession of that institution. This is a female of the edible crab,
taken in the Spring of 1897, at low water on the shore in Jersey. The
carapace measures about 8 em. by 12.5 cm. The peculiarity consists in
the fact that the great chela on the right side is wanting, and is replaced
by three small limbs resembling the normal chela, save in the minor
points to be presently described. The other limbs are normal, though
the second walking leg on the right side, and the moveable “ finger” of
the left chela are broken off. Of the three abnormal appendages two
are directed forwards and the third outwards. Again, of the two
forwardly-directed, one may be distinguished as the outer and the other
asthe inner. I shall refer to these by the letters FO and FI, while the
outward limb will be called O. FO faces outwards, FI faces inwards,
O faces forwards. Thus the three have the positions described by
Bateson! as found in such cases of supernumerary limbs, or parts of
limbs, in secondary symmetry —which is that each of two adjacent limbs
bears to the other the relation of an object to its image in a mirror.
FO and FI are each complete save for the basal joint or ‘‘ coxopod.”’
O wants also the basipod, the true second joint, fused, in this limb, to
the next or “‘ischiopod,” the true third joint. When a limb is cast off
under the influence of fear, the break always takes place in the middle of
the seeming second joint, really at the line of fusion of the basipod and
ischiopod. We shall see that this fact has an important bearing on the
case before us.

FO and FI lie close together back to back, but are quite free from
one another, save in the basipods.- This joint is distinct in each limb,
but is connected with the similar joint in the fellow limb by a bridge of
calcified material, similar to that composing the joint, at its far end.
Centrally of this bridge the two basipods are connected by membranous
skin. The basipods are not exactly similar in their ridges, etc., nor does
either exactly resemble that of the normal chela on the opposite side. Of
the other joints of the three limbs, the fourth joint (meropod) of FT has
a somewhat shrunken and distorted appearance, while the moveable
finger is bent dorsally. The sixth joint or hand of FO and O is some-
what rougher and has its ridges more prominent than that of either FI

1. W. Bateson, ‘‘ Matemals for the Study of Variation,’ p. 479. London, 1894.

100 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

or the normal limb on the other side. Otherwise all three seem fairly
normal in shape.

I have mentioned that the basal joint is wanting im each of the three
abnormal limbs. They are all inserted by means of membrane within
one large ring-like coxopod resembling that of the chela of the other side
m size, but without the large extension on the outer side that bears the
hinge for the rest of the liasb.

An assumption which there is a natural tendency to make regarding
this specimen is that the right chela may have been broken off and
replaced abnormally by three. The small size of the abnormal hmbs
somewhat supports this. On the other hand, were the above the case, .
one would expect to find that the three limbs had not only the coxopod,
but also the basipod in common, and there is, further, no reason why the
eoxopod should not resemble that of the opposite side, for there is no
trace of its having been injured. Probably then, we have to deal with a
true variation. Bateson! has shown that in such cases as this, of repeti-
tion of limbs or parts of limbs in secondary symmetry, one of the limbs
represents the normal, while the other two are a pair—a right and a
left—and further, that the additional pair bear a definite space-relation
to one another and to the normal. In this instance it is impossible to
determine with certainty which of the three is the normal limb. Still,
certain guesses can be made.

In the first place, FO cannot be the true right chela, since it is a left
limb. It lies, then, between FI and O, and of these two O seems the
more likely to be the normal, since, as we have seen, FI is closely joined
to O, which is known not to be the normal. For, to quote Bateson,
‘nearly always the extra legs are more or less compounded together at
their point of origin.” If, then, O be the normal, it has been displaced
from its true position by a pair of extra limbs in position VVA* If, on
the other hand, FI be the normal, the extra pair are in the position DDA.

A number of cases of paired extra limbs or parts of limbs in secondary
symmetry are quoted by Bateson among insects and crustacea. There
is, however, only one case recorded of complete limbs being reproduced
in a crustacean, namely, that of the left penultimate walking leg of a
Palinurus vulgaris?, Here the limbs are in a different position from those
of our crab; moreover, the three have a common basipod (with three
articular surfaces), while in the crab one is remarkable in having no
basipod, and the other two have this joint perfectly distinct in each.
Lastly, the distinguishing peculiarity of the present specimen is the
small size of the abnormal limbs.

1. Bateson, loc. cit.
2. See Bateson, loc. cit., p. 481.
8. Bateson, loc. cit., p. 527. Léger, Arin. Sci. Nat. Zool., vil. 1. p. 111. pl. 6 (1885).

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101

NOTE ON THE
PROTECTIVE DEVICES OF THE GENUS HIPPOLYTE.

BY JAMES HORNELL.

a. The colour adaptability of the adult H. varians to the hue of its
environment. i

b. The significance of the plumose hairs of H. fascigera is mimetic
and not primarily sensory.

Durinc the past summer (1897) I took advantage of an unusual
abundance in the Jersey rock-pools of the little ANsop’s Prawns, Hippolyte
(Virbius) varians, Leach, and H. fascigera, Gosse, to carry out some
experiments I had long contemplated relative to the protective coloura-
tion of these crustaceans.

That the former species is very variable in colour and that the
colours are plainly of protective value are well-known facts; thus
Professor Herdman in 1893 described in the ‘“‘ Sixth Annual Report of
the Liverpool Marine Biology Committee,” four variations of H. varians,
each agreeing in hue with the colour of its special habitat. He put
forward four alternative possibilities to account for such variability,
thus :—

1. The colours noted may represent four distinct varieties which do
not interbreed,. keep to their own special habitat, and produce young
of their own colours.

2. Or, there may be no permanent varieties, but the young may
have great adaptability and assume the hue of the habitat they find
themselves in and keep to this for the rest of their lives.

3. Or, this adaptability may be retained throughout the rest of their
lives and the adults may change hue upon change of environment.

4. Or, the young may be very variable in tint and then by the
action of natural selection, such as do not agree in hue with the sur-
roundings will be eliminated.

He added that he was inclined to regard the last as the most
probable explanation.

Starting my experiments with these possibilities in view, I collected
a quantity of both our common local species and isolated the individuals
in separate glass vessels, each containing sea-weed of a different hue to
that of the prawn.

The experiments were conclusive and proved Professor Herdman’s
third alternative suggestion to be the correct one, namely, that the adults

102 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

retain the power of changing their colour in accordance with that of
their surroundings. Thus a pale olive brown H. varians taken from
amid similarly coloured sea-weed became of a vivid green within an
hour when placed with Hnteromorpha, and the same specimen changed
to a pinkish red within three hours when placed amid Delesseria.

Again, red coloured specimens of the same species from amongst
tufts of red weed changed to green during a single night when placed
with Hnteromorpha or with Cladophora, and back again to red within
four hours when placed once more amid red weed.

These two instances are representative of a large number of similar
experiments, all having parallel results and demonstrating that the
adult Hippolyte varians has great and rapid colour adaptability.

It is a remarkable fact that this change of hue takes place as
rapidly in the dark as in the light; thus specimens placed in a dark
cupboard in company with weed of a different colour, will be found to
have assumed the colour of the weed in the course of a few hours. In
the same way individuals left over night exhibit their appropriate
colour change when examined before daybreak on the following morning.

As to Hippolyte fascigera, I find that this species possesses by no
means equal colour adaptability ; this power is much less developed.
Thus it takes considerably longer time to adapt its hue to new. colour
surroundings, and the colour is but an imperfect approximation to the
true one. For éxample, the majority of this species, which are found
living among the mottled pink coarse Corallina of our pools, and have
absolutely similar colouring, take fully twelve to fifteen hours to
approximate partially to the white tint of sun-bleached tufts of weed.

Again, a lengthened sojourn of upwards of a week amid tufts of
Enteromorpha does not effect any well marked assumption of green,
though the pink is decidedly paler and a tinge of green can be made
out without difficulty.

Such marked divergence in this power of colour adaptability between
two species so closely akin* is extremely remarkable, and I had to
make a very careful examination of the natural habitats and habits of
the species in question ere I was able to solve the problem.

I find that H. varians is infinitely more numerous and more widely
spread than is H. fascigera, being found in almost every pool, and

* Indeed, so closely akin that a cursory examination is apt to lead to the belief
that H. fascigera is a mere variety of H. varians. Many points of permanent
divergence are, however, present; the most marked is that in H. fascigera the only
spines on the upper edge of the rostrum are three placed at the posterior end and
really upon the carapace, while a single sharp tooth is set close to the tip on
the straight under edge. In H. varians, the rostrum above has one tooth set near
the base and another towards the tip, while below there is a well-marked two-
toothed keel.

PROTECTIVE DEVICES OF THE GENUS HIPPOLYTE. 103

haunting tufts of weeds of every hue. In the Zostera meadows it is
also abundant. No special preference is shown for any particular
colour or species of weed, and it is essentially ‘‘cosmopolitan.”” On the
other hand, H. fascigera is seldom found in any number except among
tufts of coarse Corallina, with which it agrees absolutely in colour, and
where it is often extremely abundant.

Thus we see that the species possessing the greater colour adapta-
bility (7. varians) is much the more numerous, and the more extended
in its range; we may safely infer that the two latter characteristics are
the direct outcome of the former. H. fascigera, being less “plastic” in
colouring, is on the contrary restricted in habitat to those weeds to
which its colour has become perfectly approximated.

We may note further that the weeds affected by the smooth-skinned
H. varians, in the great majority of cases, are smooth in surface and
not over-grown with foreign matter.

In marked contrast, the body of H. fascigera is ornamented with
tufts of brush-like hairs, especially upon the sides of the carapace, even
invading the surface of the eye-stalks; now if we examine a spray of
the coarse Corallina where this species makes its home, we will find
_ the stems covered with a multitude of abodes of tiny ‘‘messmates’’—
porcelain-like coils of the little tube-worm Spirorbis, dull looking
cylinders tenanted by that lovely minature Sabellid, Othonia gracilis, and
erusting colonies of Bryozoa protruding ever and anon circlets of hair-
like tentacles—that impart, when their owners put forth their feathery
crowns, a minutely tufted appearance to the joints of the stem. Hence
when the hairy H. fascigera is at rest on such a weed the mimetic
adaptation is greatly accentuated. The smooth H. varians in a similar
environment is much more easily detected.

As there is no doubt in my mind that the plumose hairs on H.
fascigera are directly useful as aids in protective resemblance to en-
vironment, I believe, as a consequence, that we require no longer to
accord to these hairs any special sensory function. Some authorities
have considered the hairs of this species to be auditory, and while
they presumably must possess a certain amount of tactile appreciation,
their direct utility is, I feel assured, as conducing largely to the
protective resemblance of the prawn to the appearance of its normal
habitat.

In a future number I hope to recur to this subject and to give further
details regarding the habits of these interesting Crustaceans.

104

MICROSCOPICAL STUDIES IN MARINE ZOOLOGY.

BY JAMES HORNELL.

STUDY XXIV.—FaminiAR British BRryozoa.

THE Bryozoa—better known in this country under the name of
Polyzoa—often constitute a source of delight at meetings of our
Microscopical Societies; seldom, indeed, is a microscopical conver-
sazione complete without at least one such exhibit set out proudly in
all the glory of parabolic or spot-lens illumination. The beauty of
the pellucid zooids in the full expansion of their glorious crowns of
elegantly tapered tentacles, sentient and responsive to the slightest
alarm, and the ceaseless lashing of the cilia clothing these tentacles
and creating vortices big with fate for many a tiny organism swimming
hard by, make up a picture wherein loveliness and interest chain the
attention alike of the greybeard in microscopy and of the tyro in the
science.

As a rule, the fresh-water Bryozoa are the forms thus exhibited,
being the easier to procure in inland towns. The marine forms, how-
ever, are fully as beautiful, and in some respects are much more
interesting as diversity of form is infinitely greater. If anything, the
marine forms are even hardier than the fresh-water ones, and in these
days of rapid postal communication and of Marine Biological Stations,
inland microscopists have no difficulty in studying living marine
species, and of thus comparing them with those they obtain from
adjacent pond or sluggish canal.

The Bryozoa are colonial in habit of life, except one minute form,
Loxosoma, found parasitic in multitudes of separate individuals upon
the hinder end of the great Spoon-worm (Phascolosoma). The colonies,
or zoaria, may be slender and branched (Bowerbankia), broadly folia-
ceous (Flustra), massive and calcareous (Lepralia), coiled in elegant
spirals (Bugula), gelatinous as Lophopus and Alcyonidiwm, horny, hispid,
smooth, or crusting. Almost all live attached, usually to stones or
seaweeds, and often enough we find them growing in profusion upon
the carapace and limbs of crabs. One form, Cristatella, crawls freely,
with slug-like motion, over and amongst the weeds of its pond home,
while others, the Selenaride, swim by the oar-like paddling of giant
bristles—the vibracula. Can diversity be greater? Well might the
earlier naturalists consider the slender forms to be zoophytes, and the
massive ones to be coral growth.

Later, their affinities were recognised as apart from the zoophytes
by the possession of a well-developed alimentary canal. Now they are

THE SIMPLEST BRYOZOA. 105

accorded a place among that heterogenous assemblage, the ‘‘ Worms,”
and their closest relationship is undoubtedly with Phoronis, the
Sipunculid worms, and the Brachiopods. These agree in having
tentacles round the mouth ; an alimentary canal more or less U-shaped
—the anus placed far to the front and often approximated to the
mouth ; nephridia (kidneys) reduced in number and rarely more than
a single pair; the body unsegmented and often secreting a horny or
calcareous covering; the nervous system greatly reduced ; parapodia
and setze absent.

Two popular names are in use, ‘‘Corallines”’ and ‘‘ Moss-polyps,”’
the latter being the translation of the term Bryozoa.

Simplest of all the Bryozoa are the Pedicellinde; the typical
species, P. cernua (Pallas) grows luxuriantly in Jersey rock-pools,
clothing the stems of such algz as small Fucoids, the pink Corallina,
and the green Cladophora. The individuals or zooids are stalked,
rising at short intervals along the creeping stem or stolon; in form
they have a superficial resemblance to the Bell-animalcule (Vorticella),
both having the shape of a wine-glass. Pedicellina is coy of full
expansion, and the ordinary illustrations of text-books never do it
justice ; fig. 10, pl.ix., drawn from a zooid just taken from a rock-pool,
gives a better though still inadequate idea of the graceful outward
curve of the tentacles under natural conditions. The stalk is con-
tractile and flexible and as we watch a group scarcely a moment passes
without we see one or another bob the body almost down to the base

of the stalk or maybe give a sweeping curtsey from side to side. At
another time the whole cluster may bow in unison—a most comical
sight, and one that caused me instinctively to christen it the Bobbing
Coralline when first I made its acquaintance. .

The stalk is usually spinous, but all gradations to a perfectly
smooth condition are to be met with.

The tentacles are solid and are arranged in a circlet around the rim
of the cup-shaped body. Such rim is the lophophore or tentacle-carrier.
The lophophore is not retractile as in those forms yet to be named,
but at will the. tentacles can be folded inwards to form a rafter-like
roof to the vestibule or depression found in the centre of lophophore.

A diaphragm separates the body from the stalk, and when, as some-
times happens, the former breaks off, it is not unfrequently replaced by
budding from the summit of the stalk. This tendency of the body to
break off is often very troublesome when one is endeavouring to stupefy
a colony preparatory to fixing.

Within the depression (vestibule) enclosed by the ring of tentacles
are two openings, the mouth and the anus. Between the two rises a
small lobe, the epistome. Food is directed to the mouth by means of

106 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

the currents set up by the cilia that clothe the inner or adoral surface
of the tentacles. The alimentary canal is of the typical U shape, and
is of the most primitive description.

A very curious point is the absence of any body-cavity (coelome). Its
place is taken by gelatinous tissue lying between the alimentary canal
and the body-wall. Muscular fibres are present in the stalk, and others
control the movements of the tentacles.

The nervous system is little developed, consisting of a single gang-
lion lying beneath the cesophagus, and from which nerves proceed to the
tentacles. Sensory cells are found on the outer surface of the tentacles.

The excretory organs consist of two ciliated tubes opening close to
the central ganglion.

The zooids are hermaphrodite, but it is probable that the reproduc-
tive products ripen at different periods. The larve are Trochospheres
—tiny swimming spheres characterised by a cirelet of cilia around the
body anterior to the mouth (preoral)—as in the Polychetes, and the
adults themselves retain a majority of the essential features distinctive
of this larval form in the persistence of the simple alimentary canal
of the latter, of a_ciliated ring surrounding the mouth and anus (the
tentacles are simply elongated processes of an encircling band), of the
two ciliated canals of the larva as nephridia; the epistome is present in
the trochosphere as a tufted eminence, and other minor common
characteristics can also be traced.

The larve pass a considerable period of their development within
the vestibule, which, with the tentacles protectingly overarched, forms
an efficient incubatory pouch.

The higher Bryozoa fall naturally into two divisions according as
the habitat ig marine or fresh-water. The former are distinguished by
the lophophore being circular and are termed Gymnolemata; the latter,
the Phylactolemata, by the lophophore being horse-shoe shaped. In
all, the anus lies outside of the lophophore, and this is the great
distinguishing characteristic.

Of the fresh-water forms, Lophopus and Plumatella are typical, and
resemble one another closely in all essential features. Plumatella, often
found attached to water-weeds in canals and pools, has a creeping
chitinoid stolon from which the zooids rise at short intervals. In
Lophopus, the zooids are crowded into dense tufts and enclosed in a
gelatinous matrix. In both, the zooids are capable of being wholly
retracted within the zoéecia or cell-like cuticular envelope, chiefly by
means of a powerful strand of muscular fibres (retractor muscle, 7.)
attached at one end to the anterior portion of the cesophagus and at
the other to the lower inner surface of the resistent stolon-tube.
Besides this, the zooid can be partially retracted by a set of small

\y

il

Journ. of Mar. Zool. & Microscopy.

J. HORNELL, DEL. AD Nat.
(Fics. IV., V., & VII. EXCEPTED).

TYPES OF BRITISH BRYOZOB.

113

EXPLANATION OF PLATE IX.

Fig. I.—Portion of a colony of Pluwmatella repens, sketched from life,
showing zooids in various states of expansion. (Original.)

Figs. II. and III.—Statoblasts of Plwmatella, surface and edge view.
(Original.)

Fig. 1V.—Edge view of a statoblast of Cristatella mucedo, showing the
projection of numerous barbed spines. (After Allman.)

Fig. V.—Anterior part of the body of Lophopus, seen from the right
side. The free ends of the lophophore and of the tentacles are cut
off. (After Allman.)

Fig. VI.—Life appearance of a colony of Bowerbankia imbricata, nat.

size. (Original).

ig. VII.—A cluster of zooids of the same, fully expanded. (After

Hincks.)

ig. VIII.—A calcareous colony of Lichenopora hispida, showing two

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ooecia in the centre. Drawn from Nature. (Original.)
Fi
Fig. X.—Pedicellina cernua, showing the full expansion of the tentacles.

—

g. IX.—Two colonies of the same, nat. size.

From life. (Original.)

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ig. XI.—A cluster of Pedicellina cernua on a filament of seaweed, nat.
size. (Original.)
Fig. XII.—Diagram of the structure of a Bryozoon zooid in a retracted
condition. (Original.)

Fig. XIII.—The same in a state of expansion. (Original.)

LETTERING :—d. anus ; ep. epistome ; f. funiculus; g. nerve ganglion ;
7. intestine; m. mouth; o. ovary; @. cesophagus; 7. retractor
muscle; s. statoblasts; s/. stomach; ¢. testis; v. cesophageal
valve.

CLASSIFICATION :—
Cuass.—BRYOZOA (=POLYZOA).
Sub-Class I.—ENTOPROCTA ; Anus opening within the lophophore ;
no body eavity ; tentacles non-retractile.
Family a.—Pedicellinidee—colonial.
Family 6.—Loxosomidz—solitary.
Sub-Class I1—ECTOPROCTA ; anus opening owtside the lophophore
area; well-developed body-cavity (coelom) ; tentacles retractile.
Order 1.—Phylactolaemata. Lophophore horseshoe-shaped ; with
epistome ; membrane supporting bases of tentacles; all
fresh-water in habitat.
Order 2.—Gymmnolaemata. Circular lophophore ; no epistome ; no
membrane round bases of tentacles; all marine except
Paludicella.

114

EXPLANATION OF PLATE X.

Fig. I.—-Sapphirina Hdwardsti, Haeckel, viewed from the ventral
surface, and showing the course of the alimentary canal, the dis-
position of the dermal glands, fat spheres, eyes, and ramifications
of the nervous system. (Note: The muscles, genital organs and
swimming feet, etc., are omitted.)

Fig. I1.—Anterior portion of cephalic region of same species, showing
in greater detail the arrangement of the eyes, fat-body, dermal
glands and nerve connections. \

Fig. III.—Posterior ‘‘maxilliped” (really a branch of the second
maxilla); same species.

Fig. [V.— Caudal plate ; same species.

Fig. V.cCombination of a single-celled dermal gland and a terminal
ganglion cell with its sensory bristle; same species.

Fig. VI.—Sapplirina Gegenbauri, Haeckel, ventral view to show the
eyes, alimentary canal, liver lobes and reproductive system.
(Nerves, muscles and most appendages are omitted.)

Fig. VII.—Posterior ‘‘maxilliped”’ (branch of the second maxilla);
same species.

Fig. VIII.—Caudal plate ; same species.

Fig. [X.—Caudal plate of S. Clawsi, Haeckel.

Fig. X.—A swimming foot of S. Clausi from the fourth segment,
showing the two nearly equal branches.

Fig. XI.—A similar foot from S. Darwinu, Haeckel, showing how the
inner branch is here almost suppressed.

Fig. XII.—The medium eye-spot in S. Darwini, greatly magnified.

LETTERING.—da. anterior antenna; ¢. corneal lens; d. chitinous cuticle;
f. fat sphere, secreted by the ‘‘ Fat-body”’; g. central ganglionic
mass penetrated by the cesophagus (@); h. branch of that peculiar
form of connective tissue know as the ‘‘ Fat-body”’ ; 2. intestine ;
k. stellate branches of the ‘“ Fat-body”; J. liver lobes lying
around the stomach; /s. crystalline cone; m. muscles; me. median
unpaired eye; 2. nerve; 0. anus; @. cesophagus ; p. pigment body
of the paired eyes; pa. posterior antenna; pg. peripheral ganglion
cell with its sensory bristle ; 7. spermatophore pouch; s. vas
deferens ; st. stomach ; ¢. testis; y. dermal gland; yg. double-cell
consisting of a dermal gland and a ganglion cell; x. problematical
organ (sensory ?).

(All figures after Haeckel.)

Journ. of Mar. Zool. & Microscopy.

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STATOBLASTS. 107

muscles causing a folding in that forward part of the body-wall called
the tentacle sheath, as seen in the 2nd, 3rd, and 5th zooids counting
from the left in Fig. I., Pl. IX. .

A thin membrane protects the bases of the tentacles, which are
ciliated on both surfaces. A well-marked ciliated lobe, the epistome,
overhangs the mouth (ep.).

The alimentary canal hangs as a Y-shaped bag, suspended freely in
the body cavity, and in all the fresh-water forms except Paludicella, the
body cavity (coelome) is common to all the zooids—no partitions are
found anywhere—and cilia cover the whole coelomic surface. The
cesophagus is straight. Notice, as it enters the stomach, how it is
furnished with a valvular arrangement (v.) projecting downwards and
designed to prevent any backflow from the stomach. The latter has
a great pendant bag-like region, the glandular cecum, forming the
straight part of the Y-shape. A strong cord, the funiculus, attaches
the ezcum to the outer wall or ectocyst. The intestine is short and
straight and lies parallel with the cesophagus ; the anus (@.) opens close
to the base of the lophophore.

The food consists of microscopical organisms, chiefly infusoria, spores
and the like, swept into the mouth by the currents produced by the
waving of the tentacular cilia.

_ The nervous system is again confined to a small double ganglion
lying between the cesophagus and the anus and giving off branches
to the lophophore. A delicate commissure surrounds the cesophagus.
No special sense organs are known.

No heart is present; the coelomic fluid, wherein corpuscles float,
courses freely through all parts_of the colony, kept continously in
motion by the cilia of the internal surface. Aeration is secured in the
thin-walled tentacles which are hollow, branches of the coelom being
continued into them.

ReEpRopDucTION.—The fresh-water bryozoa are hermaphrodite.
Usually the testis is situated on the funiculus (/.), while the ovary is
placed towards the forward end of the body (0.), and derived from the
endocyst or lining of the ectocyst or cuticle.

In addition to this, the fresh-water Bryozoa are remarkable for an
asexual reproduction by means of winterbuds or statoblasts. Upon
the approach of winter, the era of dissolution for the adult colony,
buds are formed on the funiculus; the cells at one end of the bud
grow round the remainder and form two convex horny plates attached
by their margins to one another, and with air cells arranged in a
- marginal ring. In Plwmatelia, which we are now describing, the
statoblast is plain, but in Cristatella it is an exceedingly beautiful
object, studded with minute knobs and provided with barbed spines

108 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

designed to aid in the dispersal of these resting buds. The marginal
air-cushion found both in this genus and also in Plwmatella and other
fresh-water Bryozoa, has obviously a similar duty. In Fig.1, Pl. IX.,
a string of statoblasts in various stages of development is seen upon
the funiculus of each zooid; while Figs. 2 and 3 give side and face
views of a single statoblast. The marginal air-cushion in mature buds
shows under the microscope as a broad black border. The statoblasts
becomes free upon the death and decay of the parent, rising to the
surface and floating at the mercy of the currents. In some genera, as
Pectinella and Cristatella, the whole parent stock breaks free and floats
freely hither and thither—an additional help in the dispersal of the
statoblasts. The latter remain without change during winter. In
spring, under favourable conditions, the valves open, and a tiny mina-
ture of the parent zooid emerges. It floats passive for a while, then
makes fast to some object, generally a water-weed, and soon by active
budding becomes a colonial parent. .

The asexual reproduction of the fresh-water Sponge by similar
resting buds should be remembered—evidently a method towards
the perpetuation of the species induced by similarly exceptional
requirements.

The Gymnolemata, which are all marine, save Paludicella, are
infinitely more numerous and in form more diverse. Fig. 13 gives a
fair diagrammatic idea of their structure, while Fig. 12 shows the same
in a state of retraction. They differ from the fresh-water forms in the
lophophore being circular and not crescentic, in frequently having the
sexes separate, and in having no asexual reproduction by statoblasts.

Bowerbankia imbricata is a typical species, often cast up on our coast
attached to the brown-podded sea-weed Halidrys. Fig. 6 shows a
branch, natural size, while Fig. 7 shows a cluster of individuals. The
cuticle is chitinous, and the zooids are very similar to the diagram
given, save that they have a well-marked gizzard at the fore part of
the stomach.

Figs. 8 and 9 show the calcareous framework of a pretty little
Bryozoon called Lichenopora hispida (Fleming), often found in caves at
extreme low-water mark within the Laminarian zone. It may also
be procured in dredging over coralline bottom, attached to the great
massive Lepralia, another caleareous Bryozoon.

Lichenopora, the Cup-Coralline, as it may be appropriately named,
is about 4 in. to + in. in diameter; a snowy-white fragile porcelain
cup, from whose hollow arise tubular columns, each the home of a
delicate zooid. The calcareous wall of this tube is equivalent to the
horny or gelatinous ectocyst or cuticle of Plwmatella or Lophopus. In
the centre of cup are usually one or two elevated trumpet-shaped
openings, the ooecia or receptacles for the ova.

AVICULARIA AND VIBRACULA. 109

In both Bowerbankia and Lichenopora the zooids of each colony are
very similar one to the other; in other genera, however, especially in
Bugula, a distinct polymorphism seems to’ take place. Bugula lives in
the Laminarian and Coralline Zones and except at very low spring
tides can only be taken in the dredge. It is fairly abundant in British
waters, and grows in loose spiral coils of great elegance. Hxamining
a spray, we find the zoéecia or cells are arranged in tabular manner,
edge to edge, the apertures all on the inner surface. The normal
zooids approach closely to the form of those of Bowerbankia, but what
arrests the attention at once is the presence of peculiar beak-like bodies
scattered over the surface. Hach is a small rounded object provided
with a curved upper beak, to which is hinged a movable jaw-like
mandible, constantly snapping viciously. The whole so closely re-
sembles a bird’s head and beak that it has received the name of
avicularium. The only internal organs are two powerful muscles used
to set the mandible in motion. According to many authorities, these
avicularia are believed to be zooids modified for a highly specialised
function, but this point is not assured. What the exact function is, is
also doubtful. The more likely theory is that they are protective,
scaring minute predatory creatures away by the constant gnashing of
the jaws; some, however, have argued that they assist in procuring
food. Thus they may sometimes be seen holding some minute worm
or crustacean in their grip and while such object is useless, from its
size, as food, yet if held till decay begins, the disintegrated particles
-may be swept into the mouth by the waving of the tentacular cilia.
Among my microscopical preparations I have now one wherein an
avicularium is holding the limb of a small Amphipod.

Whip-like organs, called Vibracula, are also seen in Scrupocellaria
and other Bryozoa, and again are thought by many to be modified
individuals bereft of alimentary, reproductive and other organs except-
ing muscles. The vibracula most probably also subserve a protective
function, their constant lashing keeping unwelcome visitors at a
respectful distance and also freeing the surface of the colony from
decaying or otherwise undesirable matter. It may also be that the
lashing serves to keep the water around in healthfu) motion and so to
bring new food particles within reach of the ciliary vortices.

DIVISIONS OF THE GYMNOLZMATA :—

Sub-Order a.—Cyclostomata. Zooecial orifaces round, without avicu-
laria or vibracula or opercular apparatus, e.g., Crisia, Lichenopora.
Sub-Order b.—Ctenostomata. Zooecial orifaces closed upon retraction
by folds of the tentacular sheath or by a circlet of spines, e.g.,

110 JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

Alcyonidium, and Bowerbankia (marine) and Paludicella (fresh-
water).

Sub-Order c.—Cheilostomata. Zooecial orifaces furnished with a
movable thickened lip or operculum, or with a sphincter muscle ;
-vibracula and for avicularia usually present, ¢.g., Aetea, Bugula,
Flustra, Scrupocellaria, Lepralia.*

STUDY XXV.—THE SAPPHIRINIDE.

The Sapphirinide are Copepoda of large size found in warm seas.
The males are free-swimming and pelagic, captured usually in the tow-
net, whereas the females are seldom taken free, as they pass their life
as commensals or messmates in the branchial cavities of such pelagic
Ascidians as Salpa.

The females differ considerably from the males in form, as is usual
with species where the sexes have divergent habits. In this article we
shall confine attention to the males.

Male individuals of this family are all of comparatively large size,
the body is dorso-ventrally compressed, and these characteristics in
conjunction with the perfect transparency of the chitinous covering
makes the Sapphiruude a splendid type-group wherein 82 study with
ease the structure of all the internal organs.

The prevailing body-form of the Copepoda is pear-shaped, and the
common Cyclops, abundant in fresh-water ponds, is a good representa-
tive. In the Sapphirinide, as already mentioned, the body is flattened ;
in contour it is oval, showing a large cephalic shield, five thoracic
segments, and an equal number of abdominal segments terminating in
two leaf-like caudal lamelle. Only four of the thoracic segments are
readily distinguishable, the fifth being rudimentary (Pl. X., Fig. 1, th.).
The first abdominal is marked by the external openings of the sexual
organs being here placed.

The appendages are of the normal Copepod type, save in the form
of the posterior antennz (p.a.) and of the appendages around the
mouth (maxille), which terminate in hook-like claws well adapted
both for clinging to the host should the Copepod be sojourning with
one, and for grasping the female during accouplement. A swimming
foot of Sapphirina Clausi of typical Copepod form is shown at Fig. X.,
consisting of an inner and an outer branch (endo- and exo-podite) of

* The marine Bryozoa live well in confinement and several kinds (Pedicellina,
Alcyonidium, Flustrella, Amathia, &c.) can be supplied diving from the Jersey
Biological Station. It is advisable to give, if possible, a couple of days’ notice. Full
particulars supplied on application to the Director.

SAPPHIRINE COPEPODS. 111

about equal size, and armed with strong oar-like bristles of great
service in swimming, Sométimes, however, as in S. Darwinit
(Haeckel), the inner branch is atrophied, indicating weaker swimming

powers.
No gills are present; the cuticle is so thin and delicate that the

whole surface of the body functions in breathing.

When seen swimming the Sapphirinids present a magnificent play
of metallic colours—the acme of iridescence—as they drive rapidly
through the water, mere sapphirine glints of darting light; the reason
for the generic name is obvious. If we examine the cuticle, the cause
of the ever-changing sheen is found to be due to excessively fine
parallel and cross rulings upon the surface that produce the optical
effect of lightning-swift colour change with every alteration in the
incidence of the light.

The cuticle is underlaid and produced by an excessively thin layer,
the hypodermus, in which lie numbers of most peculiar dermal glands.
Their proportion varies greatly in different species, attaining greatest
development in S. Hdwardsw (Fig. I.), where they are thickly scattered
over the whole body. Hach opens to the exterior by a fine duct
passing through the cuticle. Usually they are unicellular as in the
species named; more rarely they are multicellular, as in S. Darwinii,
composed of from three to seven or even more cells. Usually each
gland is accompanied by a nerve ganglion giving off a sensory bristle
or seta that projects from the surface of the cuticle. A common nerve
serves each pair, breaking into two branches ere reaching them. The
function of the glands is excretory; its activity is apparently
controlled from its companion nerve cell, which in turn receives im-
pressions from the surrounding medium through its projecting seta
(see Figs. II. and V., y., pg. and yg.).

A former article in Vol. I., p. 42, described the muscular arrange-
ment of Monstrilla, an allied Copepod. That of Sapphirina is on the
same plan.

The cesophagus passes through the centre of the ganglionic mass,
and leads directly into a dilated stomach provided with glandular
diverticula or pouches that may be considered as acting the parts of
liver and pancreas(/.). The form of this ‘‘liver’’ varies with the species ;
note how in S. Hdwardsii it forms a collar-like mass around the anterior
end of the stomach, while in S. Gegenbauwri it forms four pouch-like
branches. The intestine is straight, ending between the caudal plates.

The Nervous System exhibits great centralization. There is no
distinction into brain and ventral ganglionic chain such as is seen in
the free-swimming Copepods. All are fused into one great ganglionic
mass pierced by the cesophagus. But as a compensation, or indeed as

11) JOURNAL OF MARINE ZOOLOGY AND MICROSCOPY.

a consequence, the radiating nerves are wonderfully numerous and
strong. Anteriorly they branch off to the eyes and head appendages,
while posteriorly two great trunks are given off to supply the swimming
feet and the remainder of the thorax and abdomen. The way these
nerves divide into a network of twigs serving the dermal glands has
already been noticed.

Of Sensory Organs, the chief are the eyes, of which there are
three—two complex lateral eyes lying on either side of a small and
simple median eye. The structure of a lateral eye consists essentially
of a very large globular corneal lens (cl.) lying in front of the true crys-
talline lens or ‘‘ cone,” behind which again is a large pigment body
resting upon the ganglionic mass. The corneal lens is derived from the
cuticle ; in some species, as in S. Hdwardsii, it rests directly on the
crystalline lens; in others, as in S. Gegenbawri, and especially in S.
Clausi and S. Darwinii, quite a considerable distance separates the two
(Fig. VI.).

The sensory setz of the peripheral nerve cells have already been
referred to ; the only other sensory organ is the frontal sensory organ
‘of unknown use, seen between the corneal lenses (x). It is noteworthy

‘that the Nauplius larve of the higher Crustacea also show similar
organs, from which we may infer that this is an organ present in the
ancestral Crustacean stem.

No heart or blood-vascular system is present. The blood or
coelomic fluid moves freely in the whole of the coelome or body cavity.

Lining every part of the body wall is a peculiar stellately-branched
and very delicate form of tissue, called the Fat-body, wherein are
formed oil spheres of wonderfully large size. In sorne species they are
specially numerous, as, for example, in S. Clausi and S. Edwards, and
are symmetrically disposed. The fat-body as a whole serves as a
reserve of nourishment, and is especially useful when the animal
moults and when the reproductive function makes special drain upon
the vitality of the individual.

Repropuction.—In the males here figured, note the two-lobed
testis (Fig. VI., ¢.), stretching across the body close to the stomach.
On either side is given off a long tubular vas deferens, glandular at its
further end and then expanding into a wider region, the spermatophore
pouch, wherein numerous spermatozoa lie encased in an envelope or
spermatophore until such time as copulation shall take place, when
the spermatophore being fixed by the male wpon the genital segment of
the female, the spermatozoa break through their envelope and pass
individually into the oviducal openings.

The young pass through well-marked Nauplius stages.

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