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COMPARATIVE ZOOLOGY, |

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A HISTORY

OF THE

BRITISH

SESSILE-EYED CRUSTACEA.

BY
©. SPENCE BATE, F.R.S., ELS. Erc.,

AND

J. O. WESTWOOD, M.A.,. F.L.S.,

HOPE PROFESSOR OF ZOOLOGY IN THE UNIVERSITY OF OXFORD, ETC.

IN TWO VOLUMES.—VOL. II.

LONDON:
JOHN VAN VOORST, PATERNOSTER ROW.

Awe
*™ M.DCCC.LXVIII.

LONDON:
PRINTED BY WOODFALL AND KINDER,
MILFORD LANE, STRAND, W.C,

INTRODUCTION.

Tue term “ Sessile-eyed” has been applied to the order
of crustaceous animals forming the subject of this work
in contradistinction to that of the “ Stalk-eyed ” order,
of which Professor Bell has given an account in a pre-
ceding volume of this series. The name, with its Greek
equivalent, Edriophthalma, was first given by: Dr. Leach,
and has been recognized by all subsequent naturalists.
It must not, however, be understood to characterize every
genus that should be classed in the order. Among the
Isopoda, the genera of T'anais, Paratanais, Apseudes, and
Munna, have their eyes fixed on pedicles. In the first of
these genera, the structure differs so much in character
from that of the normal Jsopeda, that it has been classed
with the Stalk-eyed Crustacea by Fritz Miller and Anton
Dohrn. In this work we have placed it in an interme-
diate position between the Amphipoda and the Isopoda ; its
most important structural characters holding a position
nearer, but intermediate in relation between, these two
orders than they bear to the Stalk-eyed Crustacea.
While, therefore, the eyes may be considered (as they
have been since the days of the Swedish naturalist,
Linnzeus) as a ready and convenient means of classifi-
cation, separating one great division from another, this
character must be received as only an approximation to a
a2

1V INTRODUCTION.

general law. So common, however, is it, and so ready of
discernment, that it will probably be retained, even after
a more perfect, but less readily detective, system of
natural arrangement be discovered.

The term was at first applied so as to embrace all
Crustacea that were not contained in the Stalk-eyed
order, with the exception of the Czrripedia. It is still so
retained in Mr. Dana’s “ Classification of Crustacea,” and
consequently embraces a large number of forms, exclu-
sive of those described in this work, which vary so con-
siderably from each other, that we believe it is neither
natural nor desirable to group them under one definition.
In the present volumes, we speak of the Sessile-eyed
Crustacea as constituting a legion between the Stalk-eyed
(Podophthalma) and the Entomostracous Crustacea. But
the great difference of character in some animals of this
legion from the others induced Latreille to divide it into
two orders, naming them respectively after the structure
of their locomotive appendages, Amphipoda and Isopoda.
Another division was proposed by the same author, and
very generally adopted, namely, the Lemipoda, or Lemodi-
poda. he animals that constituted this supposed order
differ from the normal species of the Amphipoda only in
the absence and deficiency of parts; consequently, in this
work, they are viewed as an aberrant group of the order ;
whereas Latreille first placed the animals of this group
in the order Jsopoda,* and Lamarck united them with the
Amphipoda and Isopoda as members of one family only,
under the name of Arthrocephalés, or Capités. Dumeril,
in his “ Zoologie Analytique,”’ united the Amphipoda with
the Stomapoda, the point of similarity being the sepa-
ration of the head from the body.

The term Tvtradecapoda has been proposed for the

* Dictionnaire d’Hist. Nat.

INTRODUCTION. Vv

Sessile-eyed Crustacea by M. Blainville, in contradistinc-
tion to that of Decapoda: the one being defined by having
fourteen legs, the other having only ten. But this, upon
the most superficial examination, will be found to be the
most imperfect character, not only in usefulness, but also
in appearance. Not only all the Stomapoda, but even
the Macrura, below the family of Palemonide, possess
fourteen fully developed pediform limbs; and even in the
Brachyura and Anomura, the anterior appendages that
protect and supply the mouth are legs altered for a
necessary purpose, and not really oral appendages; conse-
quently, the distinction in structure that the two separate
names would lead a student to expect, does not exist.
The only true Decapoda are Caprella and Anceus, and
these belong, in the present system of classification, to
the Tetradecapoda.

The term Choristopoda, or separate-footed, has been
applied by Mr. Dana, who uses it as synonymous with
Tetradecapoda of Blainville and our term of Sessile-eyed,
over which it appears to possess no advantage, without
which it is unwise to add to the already too numerous list
of synonyms. ‘Thus it will be perceived that, in our con-
sideration of the orders treated of in this work, we
consider that the Sessile-eyed Crustacea bear a nearer
structural affinity with the Stalk-eyed Crustacea than with
the Trilobita, Entomostraca, and Rotatoria, which Mr.
Dana unites into the one division under the term of
Sessile-eyed Crustacea.

The classification that we have adopted nearly resembles
the system of arrangement adopted by Milne Edwards in
his “ Histoire des Crustaces ;” but, in his classification, the
aberrant Amphipoda are admitted to a rank of equal im-
portance to that of the Amphipoda, whereas certain very
exceptional forms of Jsopoda are only distinguished as a
separate family of Isopoda.

v1 INTRODUCTION.

The aberrant group of sopoda, although containing,
and perhaps based upon, the most characteristic genus of
Dana’s supposed order of Anisopoda, yet must not be con-
sidered synonymous with it, since all the parasitic forms
that possess such extremely aberrant characters in the
adult females, possess the true character of the normal
Tsopod, both in the young and adult male. Thus the
genera Arcturus, Bopyrus, and the rest of the parasitic
Amphipoda, we have classified with the normal Isopoda.
Nor can we think that the only feature that assimilates
Arcturus to the Amphipoda (the forward direction of
the second pair of pereiopoda), can be considered of suf-
ficient importance to narrow the distinction between it
and the Amphipoda, whereas other characters of greater
importance induce a natural separation that is strongly
marked.

The consideration of the structure of the Sessile-eyed
Crustacea has, until recently, but little attracted the
attention of zoologists. The observations of Loven,
Lilljeborg, Goés, De la Valette, Grube, Fritz Miiller,
Anton Dohrn, Schébl, Schiddte, and others, have done
much to show the large amount of novel and interesting
subjects of biological knowledge that have been, and still
are to be, developed by the study of this hitherto much
neglected class of animals.

The structure of these animals, though offering a very
palpable distin¢tion from the higher forms, is indubitably
formed upon the same common type. So clearly can
this be demonstrated, that we are somewhat surprised to
find that Mr. Dana (“ United States Exploring Expe-
dition,” vol. i. p. 1404) should say that “they have not
a macrural characteristic, but have a body divided into
as many segments as they have legs (hence our name
Choristopoda) ; the antenne, legs, and whole structure are
distinct in type.”

INTRODUCTION. Vil

That every segment has its appendage is a law common
to all Crustacea. In the Stalk-eyed order, the develop-
ment of the cephalon is carried to a monstrous extent as
a shield or carapace, covering and protecting, in some
cases, all the segments of the pereion. When the cara-
pace is so developed, the necessity for perfect segments
in the latter does not exist, consequently the dorsal sur-
face is wanting; but the lateral portion is always present.
In the Sessile-eyed Crustacea this enlargement of the
cephalon does not exist, and the absence of a carapace
permits the development of the dorsal surface of the
segments of the pereion. A careful examination of the
appendages of the head will clearly show the same
number of segments associated together as is found to
exist in the macrural forms, consequently the head or
cephalon in the Sessile-eyed Crustacea homologizes with
the carapace in those Crustacea that have their eyes
supported on foot-stalks. Gradually, from the Brachyura,
it decreases through each succeeding order, and this,
apparently, in relative degree with the separation of the
nervous system into separate ganglia, obedient to a
common law of depreciation, which in the Sessile-eyed
Crustacea appears to reach a lower limit in the Isopoda
than in the Amphipoda.

The appendages that are supported by the cephalon are
various in form, and generally associated with the senses.

The first, or most anterior pair, are the eyes, which,
from the circumstance of being closely impacted within
the dermal skeleton, give the name of Sessile-eyed to the
legion, as above mentioned. ‘This position is not invari-
ably the case, since in the genera Tanais, Paratanais,
Apseudes, &c., the eyes are carried on elevated stalks. In
the Isopoda these organs appear to be more perfectly
developed than in the Amphipoda, except, perhaps, in
Hyperina, where their monstrous development deprives

Vili INTRODUCTION.

the head of its normal form. In the Jsopoda generally,
the lenses of the eyes are well developed, and lodged in
the texture of the skeleton of the animal, which is fre-
quently thinned out to an extreme tenuity, and marked
with numerous facets, corresponding with the many lenses
belonging to the organ. Inthe Amphipoda, the lenses
either are not so numerous or are less apparent, and the
dermal tissue that covers the organ is thick and un-
changed in character. This condition is carried to the
greatest limit in the Phowides, Ampeliscides, and those
Gammarides that are inhabitants of deep and dark wells,
where no rudiments of eyes are apparent, except in the
presence of some coloured and ill-defined pigment cells,
which in the Phowxides coalesce into a single organ. In
the genus Ampelisca this pigment of colouring is associated
on each side with two solitary lenses, that appear to be
built into, and form part of, the dermal covering.

It appears to be a law in the decreasing structural
importance of Crustacea, that the segment supporting the
appendages shall disappear before the appendage that it
supports. In the Sessile-eyed legion, the eyes alone
remain, the segment and the articulating portion of the
appendage not being developed; the eyes are developed
in most families so deeply within the head, that they
generally appear to be behind the antennz, and some-
times, as in Phoxus, at the extremity of the frontal
rostrum; in others, as Hricthonius, on a projecting lobe
of the head, situated between the two pairs of antenne,
in which position, owing, probably, to the insufficient
depth of structure, the eye is borne on the internal
surface, where it is lodged as a protuberance. But what-
ever may be the position of these organs, the variable-
ness of situation can only be consistent with certain
advantages under peculiar conditions.

In the young animal the number of facets is fewer in

INTRODUCTION. 1x

the eye than in the adult state. In the genus Gam-
marus, the number of lenses in the young is first eight or
ten, whilst in the adult they number from forty to fifty.

The superior or first pair of antennze we consider, con-
trary to the opinion of Mr. Dana, to be formed on the
same type as those of the Macrura. Each of them con-
sists of three distinctly formed joints and a flagellum,
with sometimes a more or less important secondary
appendage. We have long since expressed our opinion
that in these organs lies the seat of auditory consciousness,
and we are still inclined to retain that opmion. We are
aware of the elaborate experiments of Dr. Von Hensen,
which tend to demonstrate the existence of auditory cilia
on several parts of the animal, as the superior antenne,
(in which Professor Huxley was the first to demonstrate,
in some exotic Macrura, the presence of highly refracting
otolithes,) on the inferior antennz, as well on the caudal
appendages as in the external branch of the posterior
pleopoda, on which Van Beneden has discovered, and we
have seen, what appear to be well-formed otolithes, of the
same type as those found in the first jomt of the anterior
pair of antenne in Mysis, &c. But we have always
attributed to certain very delicate membranous cilia of
various forms, found on the primary flagellum only of the
superior antenne, and present, under normal conditions,
in nearly every family of Crustacea, the power of convey-
ing impressions of sound. But these membranous cilia
are very distinct from the auditory hairs of Dr. Von
Hensen.*

That the superior antenn are, in their most normal
development, purely aquatic organs, we see in the depre-
ciation of their character in the partly marine genera

* An elaborate memoir on the auditory organs of the Crustacea, by Dr. V.
Hensen, was published in Zeitschr. f. Wissensch. Zoologie, xiii. Bd. 3. Hft.
1863, an abstract of which may be seen in the Zoological Record for 1864.

x INTRODUCTION.

Orchestia and Talitrus, and their rudimentary condition in
the terrestrial Isopoda.

The inferior or second pair of antennz are formed on
the simplest character of the Macrural type, and consist
of a peduncle with five joints, of which the first two, (the
homotypes of the coxa and basis joints of the true
leg,) are very closely associated, and carry the olfactory
denticle. In the higher groups, the two basal joints
are fused together, and often with the nearest part of the
segment to which they belong. Sometimes, so perfect is
the union, that not the slightest trace of the relation of
one part to another is capable of being detected. This
complete association of the appendage with the body of
the animal lessens with the degradation of the creature,
until we find the five separate joints distinguishable from
each other and from the body of the animal.

The denticle at the base of the second pair of antennz
in the Amphipoda (Vig. 1), homologizes with a perforated

Fie. 1.

tubercle situated on the ventral surface of the cephalon
in the Brachyura, laterally anterior to the oral apparatus,
and indeed covered by some of the appendages, in the
higher groups of the class. The denticle in the Amphipoda,
upon close examination, appears to have an open extremity,
through which a cylindrical tube, retained in its place by
membranous ligatures, protrudes. This tube closes at the

INTRODUCTION. Xl

internal extremity rather suddenly, and encloses the
elongated bulbous extremity of a nerve-thread, that pro-
ceeds from a second bulb or nerve-ganglion implanted at
the base of the denticle. This denticle, though frequent,
is not invariably present. In the genera Orchestia and
Talitrus, the two basal joints of the antennz are built
into the anterior wall of the cephalon, so as to be
generally mistaken for it; while in others, as also in the
Isopoda, every trace of the denticle is lost (Fig. 2).

Z

There is no secondary appendage to the inferior
antenne, and, with the exception of the squamiform plate
in the Macrura, it is never found in Crustacea; nor is it
invariably a macrurous condition, since in some genera it
is entirely absent ; and even in Palinurus, a most typical
form, it is lost as an appendage, being distinguishable
only in the outline impressed in the walls of the fourth
joint of the antenne.

The flagellum in all Crustacea originates, in the upper
antenne, after the third perfect joint; in the lower, after

Xll INTRODUCTION.

the fifth; and in every case the secondary appendage,
whether in the form of a scale attached to the lower, or a
filamentary appendage, or several, invariably in upper and
lower alike arises from the distal extremity of the third.

This appears to be a very constant condition with
all the appendages of the cephalon, pereion, and pleon.
The most frequent exception exists in the first joint
or coxa, as exemplified in the branchial appendages and
the ovigerous plates of the female Amphipoda and Iso-
poda. According to our experience, whenever any
secondary appendage is developed from the second
joint or basis, it exists more as a rudimentary effort than
as a true organ. After the third joint, we are not aware
that any secondary appendage is ever produced, though
in some genera, as in Palemon, the primary flagellum of
the anterior antenne occasionally divides or sends off a
smaller one.

The flagellum in the Sessile-eyed Crustacea is generally
wmulti-articulate. It attains its most filamentary character
in the sub-family Gammarides ; but in some genera many,
and sometimes all, the numerous articuli coalesce into one
or more joints, as in Podocerus, Corophium, Chelura, the
terrestrial Isopods, &c., in all which cases they become
organs assisting in climbing and grasping. Unlike the
superior antenne, the inferior pair appears to be always
present, and we only know of their being reduced to an
immature condition in those Crustacea that pass their
lives as parasites upon others, as the Bopyride, Hyperide,
and Cyamus, a circumstance that induces us to believe
that the second pair of antennz is the seat of a sense
which undergoes but slight modifications to enable it to
be equally distinguishable whether in air or water, since
the Isopoda and Orchestia, in which the antenne are well
developed, are terrestrial.

The oral apparatus in most Crustacea 1s a somewhat

INTRODUCTION. Xlil

complicated series of organs. It is built up of many
separate pairs of appendages, those belonging to the
higher groups of Crustacea being the most numerous.
In the Sessile-eyed orders, the mandibles are separated
from the second or posterior pair of antennze by the ven-
tral surface of the fourth or mandibular segment, and a
protuberance that, from its position, is called the labrum,
or anterior lip.

In the Amphipoda, the epistome is generally placed
vertically, and occasionally produced anteriorly into a
sharp spear-like process. In many, however, as also in
the Isopoda, it exists as a plate that gives strength and
solidity to the fulcrum on which the mandibles rest.

The labrum is divided into two parts, the lower of
which moves on the upper by a slight hinge, and assists
in perfecting the shutting of the mouth. The free margin
is generally clothed with short hairs, often of club-shaped
and deformed appearance.

The mandibles are powerful organs, impinging against
each other at their extremities, the biting edge being in
the median line. In the Sessile-eyed Crustacea, they
bear a near resemblance to the same appendages in the
larval condition of the highest order of Crustacea. The
anterior or biting margin of the mandible is generally
divided into several short and strong denticles, though in
some genera it is smooth and even. Within the denti-
cular margin a second process generally exists, a smaller
repetition of the first, and which commonly, when present,
is attached by a movable joint. Near the centre of the
mandible is a large internally projecting process, that
corresponds with and meets a similar process in the
opposite mandible, and is evidently adapted for masti-
cation, and may with propriety be named the molar
tubercle. It forms, generally, with the anterior or

XIV INTRODUCTION.

incisive margin, the two extremities or horns of a cres-
cent. The second, or articulated process, is situated
between the two, but somewhat nearer the anterior
margin. It appears to be able to assist in carrying the
food from the one point to the other, from the biting to
the grinding surfaces, between which and the molar
tubercle are frequently a row of strong and curved spines
that facilitate the process.

The mandibles are moved by powerful muscles attached
to the inner surface of the dorsal part of the cephalon,
corresponding with the homological parts that are
attached to the inner dorsal surface of the carapace
of the higher Crustacea.

The surface of the molar tubercle is granulated with
rows of minute denticles that are only visible under a
strong magnifying power. In some species, a long and
slender ciliated filament is appended to the margin of the
tubercle that may be associated with the sense of taste.

The mandibles are no exception to the fact that all
appendages are but modified legs. In all Crustacea, we
think that it can readily be demonstrated that the man-
dible consists of the first three joints being closely anchy-
losed. The small appendage, that generally consists of
three freely articulated joints, represents the fourth, fifth,
and sixth joints; the seventh, or dactylos, being seldom
present. An homological examination of the genera
Nebalia and Pontia, with Homarus, together with the
homotypical parts in other appendages in the same ani-
mals, we think will readily confirm this opinion. The
small three-jointed appendage to the mandible is wanting
in but few genera, excepting in the terrestrial Jsopoda and
Amphipoda. In aquatic species it is, with few exceptions,
always present, and appears to be of efficient use in
directing floating material towards the mouth.

INTRODUCTION. XV

In some parasitic families these organs undergo an
extreme amount of modification. This is much more
exaggerated in the Jsopoda than in the Amphipoda.
Among the Cyami, the oral appendages are all reduced
and somewhat modified, but in the Cymothoide, Bopyride,
and Anceide, among the Isopoda, they appear to lose
much of their normal character, and fulfil the office of a
sucking apparatus. In the formation of this organ one
or more pairs of the appendages may be implicated, as
is shown in an elaborate memoir by Schiddte* on the
subject. The manner in which the organ is developed in
Tone from the mandibles, we have described at page 253,
vol. 1. of this Work.

In the Anceide, the appendages of the mouth in the
young stage are sharp and lanceolate, the sucking organ
being apparently modified from the labrum, where, as
in the adult animals, the oral aperture, with the sup-
plying appendages, are lost, or converted into members
useful for other purposes.

In the genus Brachyscelus, and others of the family
Platyscelide, the appendages of the oral apparatus are
reduced to a single pair of membranous leaf-like organs ;
nor have we been enabled to trace any different character
of organ to take the place of the lost ones. Both in the
adult and young animal, the mouth appears to be reduced
to a rudimentary and simple character: an aperture with
the probable power of opening and closing at will being
the most that we have been enabled to determine.

The first or anterior maxille (Siagnopoda) are separated
from the mandibles by a posterior lip, which differs in the
Amphipoda—or at least in some genera—in being cleft lon-
gitudinally in the median line, and is termed the labium ;

* Natur. Hist. Tidssk. 1866, p. 168—206.

_ xvi INTRODUCTION.

it appears to be capable of being slightly moved, and
probably assists the mandibles in the process of manduca-
tion. There are three pairs of Siagnopoda, the two ante-
rior of which are extremely delicate foliaceous appendages,
whilst the third is much more robust, yet still possessing
a foliaceous character, particularly as regards the three or
four basal joints. In some genera, as in Sulcator, some
of the plates, particularly of the two anterior pairs, are
folded so as to become two or three parallel leaves, one of
which, on the first pair in Sulcator, is developed into a
prominent lobe, containing large nucleated cells. Of the
office or use of this gland-like organ we can offer no sug-
gestion, not having met with any analogue in the order.

The two anterior pairs, the maxill of authors, vary
somewhat in their form in genera, and very much between
the Isopoda and Amphipoda. In the parasitic species of
both orders, they are defective, and sometimes wholly
wanting.

The third Siagnopod, or first maxillipede of authors in
these orders, is a true cephalic appendage, and covers the
organs of the mouth as a protecting operculum.

These last three pairs of appendages are concentrated
about the mouth, the segments to which they belong being
represented by the ventral portions only, and these are
closely fused together, from the sides of which, in the
genus Talitrus, originate two bony processes, that meet,
without uniting, near the internal centre of the head,
there spreading out into flattened plates, from each of
which a thin and somewhat delicate process is directed
anteriorly and slightly upwards ; the stomach is supported
by them ia its position, This osseous internal arch, that we
described in the British Association Report ‘On the British
Edriophthalma,” 1855, Professor Huxley has, in his lec-
tures at the Royal College of Surgeons, published in the

INTRODUCTION. XV1L

Medical Times and Gazette, vol. xxxvi. p. 467, 7th Novem-
ber, 1857, named the Endophragmal arch (Fig. 3, En.).

The seven segments which succeed the cephalon, or
head, are, in the higher orders, protected by the carapace.
This becomes gradually smaller in the descending series,
until, in the Sessile-eyed Crustacea, each segment is
exposed and developed into a perfect ring, analogous
in appearance to the segments of the pleon in the
Macrura. The several appendages that belong to the
segments of the pereion are locomotive in their charac-
ter, some being perfectly natatorial or ambulatory, others
adapted for climbing and grasping. In this respect the
two anterior pairs in the Amphipoda are most constant
in their adaptation. The probability is, that these last
are never in the Amphipoda used, except for carrying food
to the mouth, or more rarely for climbing, or occasionally
grasping the female. In this they are found to possess

b

xVlil INTRODUCTION.

a feature that, with the exception of the Jsopoda, is
common to most Crustacea, even including the aberrant
Isopods. We have thought it convenient to describe
them under a name distinguishing them from the true
ambulatory legs, although by doing so we must include
some genera of Isopoda, where they assimilate to and
fulfil the conditions of true walking-legs. In the
Brachyura, the gnathopoda are developed, so as to
serve chiefly as protecting the oral apparatus. In the
Macrura, they assume a pediform appearance, and are
used in seizing and holding food. In the Stomapoda,
the Squillide have them developed into formidable pre-
hensile organs. This change takes place gradually from
the highest Crustaceans to the Amphipoda. 'The cha-
racter is still increased in some of the aberrant genera,
until it becomes a perfectly didactyle chela. In the
Isopoda, the prehensile character may be said to be
lost, presenting itself only occasionally in the anterior
pair, in the male animals.

The five remaining pairs of walking-legs (the pere-
iopoda) homologize with the five pairs of legs in the
Stalk-eyed Crustacea, that give the name of Decapoda
to the order. These are produced on a somewhat
different plan from the walking-legs of the Stalk-eyed
Crustacea, the modification, as it appears to us, taking
place in accordance with certain necessities that have
arisen from the depreciation of their general develop-
ment. The two anterior pairs of legs, or gnathopoda, are
developed upon one type; the two succeeding pairs, or
first and second pairs of pereiopoda, on a second; and
the last three on a third.

The normally developed appendage of every kind in
Crustacea consists of seven joints. In the Brachyura,
the first, or coxa, is anchylosed with, and forms part of,

INTRODUCTION. X1X

the sternum. In the Macrura, it also forms part of
the sternum, but the separation is distinguishable by
a free and movable articulation. In the Sessile-eyed
Crustacea, the coxa is more laterally situated, and very
firmly attached, without being fused to the segment of
the body. With few exceptions, it is developed into
a broad and scale-like joint, and is so large in the
Stegocephalide that it covers the greater part of the
animal. The object of this development is evidently to
cover and protect the branchial appendages, when situated
beneath the pereion. These scale-like coxz have been
considered as parts of the segments of the body of the
animal to which the legs belong, and are described under
the name of epimera, or side-pieces, by Professor Milne
Edwards.

There is a peculiar tendency in the Amphipoda for the
joints of the legs to be produced in a scale-like form.
Besides the cox, the dasis, or second joint of the three
posterior pairs of pereiopoda, are almost always so de-
veloped. In Orchestia, the males in some species have the
carpus and posterior pair of pereiopoda enlarged ; in Podo-
cerus and Cerapus, the two anterior pairs have the basis
so produced; but in Sulcator this predisposition appears
to reach the culminating point, where it is apparent in
almost every joint of the appendages of the head and
body.

The next division of the animal is that which we deno-
minate the pleon. It consists of seven segments, as in
each of the former divisions, and carries three kinds of
appendages. The segments generally resemble those of
the pereion, and, like them, carry on each side squamiform
coxee, which Professor Milne Edwards has again mistaken
for epimera, or side-pieces, belonging to each respective
segment. ‘These are, both in the Amphipoda and Isopoda,

b2

XX INTRODUCTION,

generally fused closely with the dorsal surface of the seg-
ment; but in the genus Apseudes, as we have shown in
fiz. p, page 148, vol. ii., they are free. Here we havea
distinct exposition of the relation which the squamiform
side-piece holds both to the segment and the movable
bifurcate appendage. The segment is distinctly separated
from the squamiform side-piece, which, articulating with
it, forms the first joint of the pleopoda or swimming-leg,
and is developed into a large scale-like process, to the
base of which the second joint is articulated, from whence
is suspended freely a third, which in its turn supports the
two free plates which form the terminal appendage of the
anterior pleopoda. In the Lsopoda, as well as the Amphi-
poda, this interpretation illustrates the relation of the
parts of the pleopoda to the segments of the pleon. The
forms of the pleopoda may and do change, according to
the law of modification of parts, to suit their require-
ments ; but under whatever condition they may exist, they
consist of three normal joints, more or less fused together,
and with the segments of the pleon and a depreciation of
the four terminal joints into one or a pair of movable
plates, as in the Isopoda, or articulated flagella, as in the
Amphipoda.

The three anterior pairs in the Amphipoda are deve-
loped upon this type; the two succeeding have the double
appendages stiff and unyielding, and the posterior is
generally variable in the different genera. In the Jsopoda,
the four anterior pleopoda are developed upon one type,
while the fifth is converted into an operculum. Some
variation of the anterior pairs also takes place in relation to
the sex of the animal. The last, or twenty-first segment,
differs from the rest in most Crustacea by not carrying
any appendage. To this we know of but one exception
among the Crustacea, and that is in a genus in the family

INTRODUCTION. XXl

Myside, discovered by Mr. Norman. The telson in the
Sessile-eyed Crustacea is generally an abortive, and fre-
quently a rudimentary, part. In the Isepoda, except in
the genera Apseudes and Anthura, it is always fused with
the preceding segment.

The composition of the dermal skeleton is, in all Crus-
tacea, the same. In the Sessile-eyed order the texture is
very thin, and seldom consolidated into a firm structure,
except in certain parts of some few genera where strength
is required, as in the chele of large-handed species. This
circumstance offers the advantages of enabling the
observer to examine the internal structure of the animal
without the necessity of dissection. During the life of
the animal, we are enabled to trace the currents of circula-
tion of the blood, the motion of the cardiac vessel, and the
position of the internal organs in relation to each other.

This delicacy of the structure also enables us to dis-
cover the very diverse and varied arrangement of the
material of which it is built up, and demonstrates (con-
trary to our anticipations) that in species often closely
allied, there is a very distinct appearance in the micro-
scopic structure. It may prove to be of some importance
in determining species, but care should be taken that the
several specimens examined should be taken from the
same part of the skin of each animal. We have illus-
trated many of these varieties of structure throughout the
work, in connection with the animals to which each
belongs.

Frequently, besides the markings that illustrate the
manner in which the skin is built up, there is another
that is not always constant, consisting of a series of small
perforations through the tissue, which in some species
assume a waved appearance, as may be observed in the
genus dAmpelisca.

XXll INTRODUCTION.

Although we believe that the microscopic examination
of the skeleton in these animals would frequently facili-
tate the determination of doubtful species, yet it is a con-
dition that is not to be trusted to alone, inasmuch as it
is not unfrequently found that similar appearances are
repeated in very distinct genera. Examples of this may
be found on comparing the structure of Megamera Otho-
nis with that of Chelura terebans.

The form and structure of the hairs that are found on
these animals, when microscopically examined, are of a
very distinct and different character. They not only
vary in separate species, but differ in several parts of
the same animal. In Suwulcator there are no less than
twelve varieties. Some are plain, stiff, bristle-hke spines
of various lengths, which are generally attached to
the margins of the limbs. A second variety, longer in
general form, frmged on one side with a series of fine,
straight, teeth-like processes, possessing a rake-like cha-
racter, is attached to the third siagnopod ; as is also

A third, that differs from the preceding in having the
teeth bent in a curve directed to the base.

A fourth is found on the carpus of the second pair of
gnathopoda. In this position are also two varieties, which
originate from closely approximating bases. One is long,
slender, and clean to the tip, where a few exquisitely
fine cilia appear, which give to the extremity a bulbous
appearance, that can be resolved only with a high (700)
magnifying power. ‘The other, or

The fifth, is short, broad, flat, terminating in a point that
is sharply bent upon itself; the lateral margins are like-
wise furnished with a series of sharp denticles, ranged on
each side, pointing to the base for about two-thirds of its
length.

A sixth is found on the propodos of the same appen-

INTRODUCTION. XX1l

dage; comprising two forms moulded on the type of the
two preceding ; the shorter changing the hooked extremity
for a bulbous termination, and the shaft being armed with
teeth on one side only.

A seventh exists on the mandibular appendage: it is
straight, enlarged and rounded at the apex, and serrated
on one side; while

An eighth differs from the preceding in being more
robust, slightly turned at the extremity, and smooth along
the margins, excepting a single short, straight, distally
directed cilium.

A ninth resembles the sixth, but wants the serrated
margin, and carries on the convex side a fine cilium.
This variety is found on the first pair of gnathopoda.

The tenth, eleventh, and twelfth varieties are plumose,
and found mostly on the second pair of antennz, though
a few are present on several other parts of the animal.
One is short and obtuse, being crowned with numerous
radiating cilia. It is to this variety that we understand
Professor Hensen attributes the power of hearing.

This great variety of form in the hairs of a single
species is not constant. In the genus Talitrus, there is
but a single form of hair, which is but httle modified in
the various parts of the animal. It is short, stiff, and
blunt, and exhibits under the microscope a tendency to a
spiral condition for about one-fourth from the extremity,
at which distance a second but smaller process exists, so
that the hair might be characterized as being forked, but
for the unequal proportion of the two branches. This
kind of hair is by no means rare in the Amphipoda.
Those found in Orchestia, Talorchestia, Nicea, Gammarus,
&e., are but modifications of the same form. This great
variation in the form of the hairs is more or less common
to all Crustacea. Those in Carcinus menas have been

XXiV INTRODUCTION.

described and figured by Dr. McIntosh in the “ Linnean
Transactions ” for 1862, p. 79. The hairs are not only
various in form, but sometimes they will be found con-
stant in number. Thus, in the genus Phowus, we have
found the number of hairs on the coxe of the three or
four anterior pairs of legs to be constant in the respective

species.

EXUVIATION AND REPRODUCTION oF LiIMBs.

The power of Crustacea to throw off their skin and
replace it by a new one, has long been a recognized fact
in all the higher orders. It is, however, on the authority
of Mr. Couch, stated by Mr. Bell, in a note to his intro-
duction to the “ Stalk-eyed Crustacea,” p. Ixi., “ that the
families in which the eyes are sessile in their adult
growth . . . . do not exuviate, or voluntarily throw
off their hmbs.”

These Crustacea, however, like their higher congeners,
renew their integumentary tissues periodically. This is
equally true with regard to the alimentary canal, which is
cast in connection with the skeleton. The animal shows
no appreciable difference in its habits at the time imme-
diately anterior to its throwing off its exuvie. It swims
about very actively until the hour of moulting arrives,
when it seeks a place of comparative security, where it
may remain uninterrupted the necessary length of time
for the completion of the process.

In this position it grasps with the anterior pair of
gnathopoda some fixed and conveniently secure material
for an anchorage. Here the labour is commenced, and,
judging by the quietness and rapidity of the process,
appears to be one of no great discomfort. During the

INTRODUCTION. XXV

operation, at almost any stage, the animal, if disturbed, is
capable of removing itself to a more quiet and secure
place.

The process appears to be the result of an internal
growth of the animal, which becoming too large, the skin
splits at the margin of the dorsal and sternal arches of
the three anterior segments of the pereion, the inferior
arch carrying the legs, inclusive of the coxz.

The anterior segment of the pereion extends over the
posterior margin of the cephalon. At this point the
attachment is broken anteriorly, and the lateral disunion
of the three anterior segments allows their upper surfaces
to be raised as a movable lid, through the opening of
which the animal escapes from the old integuments.
With some exertion, the posterior portion of the body,
together with the limbs, are withdrawn, after which the
head and the anterior members are removed, and the
entire animal is free from the old exuviz, which, resem-
bling a dead individual, is left, attached to its old position.
Unless disturbed, the animal, which is now extremely
soft, generally rests for some time, as if exhausted, near
the cast-off skeleton. Upon being disturbed, it is capable
of swimming away immediately.

Mr. Harry Goodsir, in the Edinburgh Philosophical
Journal for 1842, has described the process of exuviation,
as observed by him in the genus Caprella.

He says that the animal, previously to the commence-
ment of the process, “lies for a considerable time languid,
and to all appearance dead. At length a slight quivering
takes place all over the body, attended in a short time
with more violent exertions. The skin then bursts behind
the head in a transverse direction, and also down the
mesial line of the abdominal surface ; a few more violent
exertions then free the body of its old covering. After

XXVl INTRODUCTION.

this the animal remains for a considerable time in a
languid state, and is quite transparent and colourless.”

The new creature is a perfect representation of the old
one, slightly enlarged. According to our observations,
every hair is produced complete. We have often seen
them, convoluted and bent up within the old case, from
which they only wanted to be freed to assume the erect
position of the perfect hair. It has, however, contrary to
our anticipation, appeared that all the hairs are not de-
veloped within each corresponding one. We have fre-
quently observed them as a second armature, independent
of the old one. This remark is particularly distinguish-
able in the teeth that fringe the first two siagnopoda.
These have generally a dentated and forked character,
which might be injured in their removal from the old and
hard tissue of the rejected skin, an accident that not
unfrequently befalls the branchial sacs, which are occa-
sionally torn off and retained behind in the old case.

The power of Crustacea to throw off any of the limbs
upon receiving an injury, and sometimes in consequence
of fright, is well known in relation to the higher orders.
The manner in which this is done has been described by
Dalyell, Goodsir, and ourselves. It certainly is a remark-
able power and law of reproduction, and which always
takes place at the same homotypical position in every
limb—that is, between the coxa and the next succeeding
joint. The wound that is caused by this sudden rupture
is simultaneously glazed over by a thin membrane, which
must be very suddenly formed, and probably is the ampu-
tating power. Observers have very generally added as an
appendage to the above interesting fact, that it is exceed-
ingly fortunate that there is this power of voluntary
amputation of the limbs, for otherwise, in consequence of
the non-contractile character of the dermal covering, the

INTRODUCTION. XXVll

animal, upon being wounded in either of the limbs, would
of necessity bleed to death. That such would be the case
would appear to be extremely probable, but, like all nega-
tive evidence, is only of value in the absence of direct
testimony. In the Sessile-eyed orders the animal appears
to want the power of voluntarily throwing off any of its
appendages, no matter how severely it may be wounded.
If a leg be cut off, or in any way injured, the wound
very soon after becomes cicatrized with a black scar,
which remains until the next exuviation of the animal,
when the entire limb is thrown off with it, and a new one
commences growing.

Taste AND DIGESTION.

The sense of the enjoyment of food, even in the highest
types of the animal kingdom, exists rather in the power
of parts to receive impressions than in the presence of
any especial organ for the purpose. Arguing, therefore,
from analogy, we should suppose that the sensation of
taste in the lower animals (such as the Crustacea, and
other groups in which mastication is of an imperfect
character), must necessarily be rather a faculty peculiar
to the mouth in general, than the result of any especial
organ adapted for the purpose. .

From the mouth the csophagus leads directly to the
stomach. The passage is very short, being directed up-
wards and forwards; it enters the stomach at the infero-
anterior margin, and, as in all Crustacea, is within the
limit of the cephalic region.

Just within the anterior opening of the stomach are
situated two rake-like organs, the teeth being placed in
a row on an arched base; they are slightly curved and
dentated on the margins. ‘They are so placed as to have

XXVill INTRODUCTION.

the points directed inwards, so that food can readily pass
into, but cannot return again from, the stomach. The
teeth on each side appear to correspond, so that they
probably play an important point in tearing and lacerating
the food as it passes into the stomach. Posterior to this

Fic, 4,

triturating apparatus there exists four leaf-like plates,
fringed with long and powerful cilia. These are attached
to the lateral walls in pairs, one auterior to the other;
immediately above the second or posterior pair, appa-
rently in a chamber of its own, is a gizzard-like apparatus.
We observed this most distinctly developed in Sulcator
and Talitrus, and we believe it to be present in all the
Amphipoda, and we take it to be the same appendage
which Bruzelius and Loven figure and describe as the
‘‘mellanbalkan,” which is situated within the “ blind-
sacklikt organ,” and not, as their figures * would lead one
to believe, on the floor of the stomach.

* Ofversigt af K. Vetensk. Akad. Forhandl. 1859, pl. i., figs. 1, 3, 8.

INTRODUCTION. XX1X

This apparatus, under a high magnifying power, is seen
to consist of several closely packed rows of fine strong
short hairs, very commonly arranged together in the form
of a heart, the apex of which, directed anteriorly, is
truncated. This appears to be the most general appear-
ance, though in various genera it is different in form.
Its appearance suggests its capability for triturating and
grinding food, though it is curious that two such kinds of
apparatus should exist at each end of the stomach, the one
at the cesophageal entrance, the other near the pyloric
outlet. The cavity in which the latter is placed has the
walls thickly covered with very short hairs.

In the genus Talitrus, posteriorly to this apparatus are
placed two long czeca, one on either side of the posterior
opening of the stomach. ‘These ceeca are not universally
present in other genera. They are delicate prolongations
of the walls of the stomach, and gradually narrow towards
their free extremity. They probably supply the stomach
with a gastric juice. Still more posteriorly, at the point
where the stomach terminates and the alimentary canal
commences, are situated from four to six long ceca-
like lobes, filled with hepatic cells. These are attached
to the inferior surface, forming the liver, and are
earried parallel with the alimentary canal. In the
Amphipoda, as illustrated in Gammarus, the liver con-
sists of four sub-equal lobes; in the Jsopoda, as exempli-
fied in Ligia, it is formed of six lobes, two of which are
much longer than the other four, and have a slightly
waved or tremulous-looking appearance towards the free
extremity. From the pyloric orifice of the stomach the
alimentary canal in all Crustacea passes, without curve or
inflection, straight to the anal termination under the
telson. To this we know of but a single exception, and
that on the authority of Professor Alman, who says :—
“In Chelura, the alimentary canal is so arranged as to

XXX INTRODUCTION.

shat one part within another, so as to admit of the head
being projected forward, that the animal might eat its
way into the wood that it penetrates.” This we have not
been able to verify, nor can we see the necessity for the
disarrangement of the stomach with all its attachments,
when a prolongation of the cesophageal canal would
enable the animal to accomplish the work on far easier
conditions.

The structure of the alimentary canal is longitudinally
fibrous. In the genus Ligia, a little anterior to the anal
termination, a series of transverse muscular bands sur-
round it without uniting on the under surface, and
probably fulfil the office of sphincter muscles.

About two-thirds of the distance between the stomach
and the telson, one or two appendages are attached to the
alimentary canal in the Amphipoda. We say one or two,
because we have distinctly dissected out two in Sulcator
(Fig. 5), but have failed to determine more than one in

Pie. 5.

Gammarus (Fig. 6), Mera, and other genera. The organ
is free at one extremity, and is borne in a forward posi-
tion, resting on the dorsal surface of the primavia. It
is more important in appearance in some Amphipoda than
in others; in Suleator it is very long. We have never seen
it in any of the Isopoda that we have examined, but, as far
as our experience supports us, it is present both in the
male and female Amphipoda, in the adult as well as in the

INTRODUCTION. XXX1

larval stage. In the younger form (Fig. 7) it is rudi-
mentary, but scarcely more so than in Mera (Fig. 8).

Fic. 6.

Immediately posterior to the point of attachment of this
organ with the alimentary canal are a series of muscular
bands lying transversely across the latter, which probably
fulfil the office of sphincter muscles by compressing the
passage just posteriorly to the efferent orifice of this sup-
posed urinary organ. Muscles very similar in appearance
are situated near the terminal exit of the alimentary tube,
and probably fulfil the office of sphincter muscles to the
anal outlet.

The contents of the appendage that we call the urinary
organ are, under an object-glass of one-fifth focus,
resolved into small round cells, containing a granular
nucleus (Fig. 9). These cells are closely packed together,

Hie. 7. Fic. 8. Fic. 9.

but not so as to lose their rounded character, and the
whole are confined within stout walls.

XXxll INTRODUCTION.

CIRCULATION.

The circulatory system in the Amphipoda differs very
importantly from that of the Jsopeda. According to some
researches of Professor Wagner * on the genus Porcellio,
there exists a well-developed arterial system in the
Isopoda. To establish this he adopted the method that
was first shown to be practicable by M. Emile Blanchard,
and which has since been successfully pursued by M.
Kowalewsky on Jdotea. A mixture of glycerine and
water coloured with carmine injected through the heart
into the circulatory system, demonstrates the existence
of distinct vessels for the passage of the nutritive fluid.
The greatest amount of arterial development, as might
have been anticipated, is found to exist in the cephalic,
branchial, and generative regions, which the author
illustrates by diagrammatical figures. In the Amphipoda,
the heart is situated in the dorsal region of the pereion,
reaching from the posterior extremity of the first segment
to the posterior of the fifth. It is a long, simple, sack-like
vessel, consisting of elastic fibrous walls, possessing more
the features of a great arterial vessel than that of a true
heart. The blood corpuscles pass posteriorly from the
pulsating heart through the entire length of the animal
immediately above the alimentary canal, and the great
venous course returns along the dorsal surface, probably
on each side, until it reaches the last segment of the
pereion, where it dips to the ventral surface and enters
into the branchial sacs, where it passes down the anterior
margin and up the posterior, then direct to the heart,
which it enters by three lateral pulsating oblique aper-
tures.

The heart of the Jsopoda is situated within the dorsal
surface of the pleon, except in Tanais, and probably

* Ann. des Sc. Nat. p. 37, vol. iv., 1865.

INTRODUCTION. XXX1l1

other generalof the aberrant type, where it is situated,
according to the observations of Fritz Miller, in the dorsal
surface of the pereion, corresponding in position with that
of the respiratory systems of the various orders.

In the Amphipoda, the branchiz are by no means the
simple sacs that they have been described. They are
situated upon the inner surface of the coxe, and assume
the form of leaf-like hollow plates, ranged in parallel lines
on each side of the sternum (Fig. 10), and are attached to
every pair of legs except the first in
the females, and generally the last
in males ; though, in Gammarus, we
have seen the seventh pair fur-
nished with branchie as well as the
preceding. In the Aderrantia, the
number of sacs is reduced to two
or three pairs. In this order they
homologize with the branchie of
the decapod type, each branchial
appendage being viewed in the light
of a single plate of the compound
organs of the higher type; or rather,
perhaps, they bear best comparison
with the same organ as it appears
in the larval condition in the
Brachyura. The great distinction
in their character is derived mostly

from the appearance which these

Fic. 10, organs assume in the higher forms,
being that of an internal position. But this is one
of appearance only. The branchize are overcapped by
the monstrous production of the cephalic shield in the
Stalk-eyed orders of Crustacea, a circumstance that gives
to the portion of the dermal skeleton that it covers the
c

XXX1V INTRODUCTION.

character and appearance of an internal skeleton. The
branchial organs are covered and protected, but they are,
nevertheless, essentially external appendages. In the
Amphipoda this condition does not exist; consequently
the branchiz are pendant in the water, and placed on the
inside of the pereiopoda, the first joints of which are
developed into large squaminiform plates for their more
efficient protection.

The internal structure of these organs appears to consist
of thick fibrous tissue attached to the inner surface of the
wall of each sac (Fig. 11). The fibrous tissue is arranged

in patches of irregular form, but which correspond in
their arrangement with one another. These patches are
largest near their centre, and thin out towards their mar-
gins: the result is that a channel is left between each. All
the channels so formed are connected together throughout
the entire organ, and exhibit a continuous labyrinth,
through which the blood circulates in many small
streams.

Should the animal become feeble, a gradual accumula-
tion of corpuscles takes place in different parts of the gills,

INTRODUCTION, XXXV

mostly at first out of the reach of the stronger currents.
As the vitality of the animal diminishes, the arterial
current is observed to lessen in force, until it is propelled
only by jerks, coexistent with every pulsation of the
heart.

RESPIRATION.

The organs of respiration in the Isopoda are homo-
logically distinct from those of the Amphipoda. We have
already stated that Professor Wagner has shown, in the
genus Porcellio, and M. Kowalewsky in Idotea, that the
blood in the Zsopoda runs in arterial channels. We are

Fie. 12.

not aware that any of the Amphipoda have been put to the

same test as the two genera named in the Jsopoda; and

certainly, to microscopic observation, the structure of the
c 2

XXXV1 INTRODUCTION.

branchial appendages and other parts of the system that
from their transparency and tenuity may be conveniently
examined, afford presumptive evidence against the circula-
tion of the blood being confined to walled channels.

In the Isopoda, the branchial organs are variously diffe-
rentiated. In some, as Ligia, for example, the passage of
the circulating fluid through the branchial plates is clearly
and distinctly defined (Fig. 12). The main artery, com-
mencing at the base, gives off numerous lateral branches,
that divide and sub-divide into a rich plexus with abundant
capillary vessels. In the genus Spheroma, the branchial
organs consist of a series of plates attached
to the posterior wall of the fourth and
fifth pairs of pleopoda (Fig. 13). In the
degraded family of the Bopyride, the bran-

chial organs are depauperated to the lowest

A degree, being in some genera little more
Fig. 13. than excrescences on the ventro-lateral
margins of the pleon.

In Tanais, the true branchize have not been clearly
determined. It is the opinion of Dr. Fritz Miller, Van
Beneden, and Doctor Anton
Dohrn, that an appendage
attached to the first pair of

gnathopoda is not a branchial

organ, but a flabelliform ap-

Fig. 14.

pendage, that by its constant
and unvarying motion induces the surrounding medium
to flow over the branchial appendages that as yet have not
been discerned.

At page 122 of the second volume of this work we
have described and figured one of the pereiopoda with a
sac-like appendage attached, that we considered as the
homologue of the branchial sac in the normal Amphipoda.

INTRODUCTION. XXXV11

This appendage appears not to be constant im all species,
nor in all specimens of the same species. If, therefore, it
be the homologue of a branchial sac, it can only be an
organ of repetition.

Fritz Miller is quite positive in the assertion that no
corpuscles of the circulating fluid pass into the caudal
appendages, which are the seat of the branchie in the
normal Jsopoda.

The terrestrial Jsopoda have the respiratory organs some-
what modified from those of the aquatic species. These
have been described and figured by MM. Duvernoy, Sa-
vigny, Lereboullet, and Professor Wagner. M. Savigny,
however, was the first to show that in the genus Zylos
the system of respiration was carried on by two separate
means ; the one by branchiz, as im aquatic Crustacea,
the other by the spiracular air-tubes. This has been
recently confirmed by Professor Wagner, who shows the
relation of the opercular valves to the respiratory system,
and contends that, besides their power of protecting the
branchial plates from injury, and precluding the too rapid
escape of moisture, they fulfil, by means of a plexus of
minute vessels, situated at the base of the operculum, a
pulmonary function. This organ, which he figures, has,
he says, a kind of tracheal division into numerous rami-
fications. Seen by transmitted light it is opaque, but
viewed under a direct light it is silvery white; and he
contends that it is a pulmonary or tracheal chamber,
which serves as a supplementary organ to the true
branchize. This view is supported by M. Milne Edwards,
as may be seen by the reference to the “ Atlas du Régne
Animal,” (Pl. 1xx. fig.].m.), and ‘ Lecons sur la Physiologie
et PAnatomie comparée,” t. ii. p. 141. Our own opinion
relative to these organs on the branchial operculum is
that they are glands for the secretion of a fluid that

XXXVill INTRODUCTION.

assists in lubricating the branchial plates in warm and
strongly evaporating atmospheres. We have been led to
this conclusion from finding that they diminish in size in
those specimens that have been long detained in dry
places

GENERATION.

The organs of generation in the male of the Sessile-
eyed Crustacea are not to be determined without great
nicety in dissection and care in manipulation. We have,
however, in Sulcator among the Amphipoda, and Ligia
among the Jsopoda, been able to examine them clearly,
besides less perfectly so in the animals of other genera in
both orders. Bruzelius and Loven have given their atten-
tion to the former order, and demonstrated the arrange-
ment in the genera Gammarus and Podocerus. The male
organs internally consist of a more or less oblong pair of
testes, which are lable to vary somewhat in form in
different genera. These testes are fitted with numerous
small seminal cells. A narrow passage, or vas deferens,
connects this organ with a second oval chamber, or
vesicula seminalis, which is filled with long fine hair-like
spermatozoa, lying thickly coiled one upon another.
From the vesicula seminalis a narrow passage leads to the
inner surface of the first joint of the seventh pair of legs,
where it penetrates in each into a soft membranous
external penis. We have kept species of Amphipoda long
under observation, and paid close attention to their habits,
but have hitherto failed to detect any communication
between the sexes which would admit of a direct passage
of the penis into the vulva of the female.

The male Amphidod grasps the female by one of its
strong subcheliform gnathopoda, inserting its claw
beneath the anterior edge of the first segment of the

INTRODUCTION, XXX1X

pereion, whilst another is inserted beneath the posterior
margin of the fourth or fifth segment. Grasping the
female in this way, the male draws it into immediate
contact with itself, so that the dorsal surface of the female
presses against the ventral surface of the male. In this
attitude, more or less firmly compressed, they swim about
or rest on any convenient surface for many days. If the
two be driven asunder through fear of any danger, the
female seeks a place of shelter, while the male swims
more actively about. Should the male swim within some
little distance of its late companion, it becomes imme-
diately aware of the circumstance; and we have seen it,
after having passed the spot, abruptly turn back, seek her
out, and seize her with avidity from amidst a numerous
mass of others. Immediately after securing, he strikes
her with two or three strong lashes of his tail. The
female, rolling herself closely up, is carried off by her
more powerful mate.

This contact between the two sexes is either occa-
sionally repeated, or it may last
throughout the entire period of incu-
bation. We have frequently taken
them so coupled, even when the young
have been so far developed as to be
enabled to leave the care of the
parent. We are induced, from this
fact, to believe that a series of broods
may take place successively through
the year, and that the erotic state of
the female may exist during the period
of incubation.

The penis (Fig. 15) is a soft membranous tube, that
terminates in a small orifice. It probably has, under
certain conditions, the power of becoming harder, but

Fie. 15.

xl INTRODUCTION.

it generally hes pendant from the inner side of the coxa,
and is longer in some species than in others. In the
genera Proto and Caprella, the penis seems to be
formed out of the anterior pairs of pleopoda, just as
is the case in the Brachyura, among the Stalk-eyed
Crustacea. These observations are further confirmed by
those of M. Rousel de Vauzeme on the genus Cyamus.
In the Jsopoda, these organs have been carefully worked
out by Siebold, Lereboullet, and Schébl. In the genus
Ligia (Fig. 16), we have observed on each side three testes,
consisting of long narrow
vesicles, thinning away to
exquisitely fine filamen-
tary prolongations. These
vesicles increase in dia-
meter as they approach
towards the efferent duct,
where they rapidly be-
come constricted before
uniting with the vas defe-
rens. These vesicles are
filled with seminal cells,
and are, we believe, the
true “testes: “Mi. dlere-

boullet, however, in his
researches on the Onis-
cide,* states that he has
observed that each of
Fic. 16. these fusiform sacs has

attached to its extremity other irregular sacs, which
he regards as the principal secreting organs, and con-
sequently the spermogenic glands or testicles. These

* Mém. sur les Crustacés de la Famile des Cloportides, par A. Lereboullet.
Strasburgh, 1852.

INTRODUCTION, xli

organs, which have previously escaped the observation of
anatomists, the author says, “are very irregular sacs,
variable in form, simple or compound ; they are generally
about three-quarters of a millimetre in length, but some-
times less. They are situated deeply on each side the
stomach, and are retained in their position by delicate
but strong ligaments, which are covered with black pig-
ment, which lose themselves between the muscular fasciz.
of the segments of the body. These organs are full of
cells, that M. Lereboullet considers as the spermatic
cellules. The second vesicles, or those which we thought
to be the true testes, M. Lereboullet calls testicules acces-
soires. They are, he says, three in number on each,
enlarged towards the middle; they thin out insensibly
towards the extremities: at one end they unite with the
organs that M. Lereboullet calls the testes, and at the
other they open into the spermatic reservoir—the vesicula
seminalis. These accessory testes contain cells which are
of two kinds, the larger being less numerous than the
others. From these vesicles an efferent duct leads to the
vesicula seminalis, which in Ligia is a long and narrow
vessel, increasing in breadth gradually as it approaches its
extremity, where it is suddenly constricted to a narrow
outlet, which, covered with black pigment cells, leads
direct to the external penis, which is situated near the
centre of the ventral arch of the seventh segment of the
pereion. In the males, processes of the branchial appen-
dages are developed into stylets, (vide fig. 12), that we
suppose must have some secondary influence in the pro-
cess of fertilization.

The anatomy of the reproductive organs in the females
has been carefully worked out by MM. Loven and Bru-
zelius in the Amphipoda, and by Lereboullet and Schobl
in the Lsopoda.

xl INTRODUCTION.

According to the former authors, corroborated in part
by Mr. H. Goodsir on the genus Caprella, by Roussel de
Vauzeme on Cyamus, and from our own direct observa-
tion on Gammarus, &c., the internal organs consist of
two sets of ovaries. These are long cylindrical bodies,
having a duct near the middle, on the inner side, that
opens into the vulva, which is situated on the inner side
of the coxa of the third pair of pereiopoda, or fifth pair of
lees. According to the latter authors, the structure of
the same organs in the Jsopoda is very similar; but
M. Lereboullet has failed to trace the connection of the
ovaries with the vulva. Herr Schobl has been more suc-
cessful in his researches on the genus Typhloniscus, and
has figured them attached to the inner surface of the
fifth pair of legs. He has also described and figured a
pair of receptacule seminales, in which the male animal
deposits the spermatozoa that fructifies the ove. Accord-
ing to this statement, in the [sopoda, if not in the Amphi-
poda also, the male impregnates the female by direct
intromission—a circumstance of which we have entertained
some doubt, partly arising from the formation of the
animals themselves, particularly of the Amphipoda, in
which the development of the cox and the narrowness
of the animal would almost, it would seem, preclude the
possibility of the sternal portions of the animals being
brought into immediate contiguity, and also from the
circumstance of having watched the animals, particularly
Asellus, from previous to impregnation to the birth of
the young, we have never seen the male in any position
relative to the female except in that previously described.

The incubatory pouch, in which the ova are deposited,
from the period of their fertilization until the young are
developed sufficiently for independent existence, is the
result of the folding over of several lamelliform plates,

INTRODUCTION. xlili

generally fringed with hairs. One of these plates is
developed on the inner side of each of the two pairs of
~_ gnathopoda (Fig. 17), and the two

—~

an terior pairs of pereiopoda, These
plates overlie each other in a compact
form, securely protecting the ova, or
the immature young, from external
accidents, as shown in fig. 10, p. xxxiii.

It is the opinion of Von Siebold
that these appendages are periodically

developed at the “époque du rut.”

Fic. 17, This we have not, from our own obser-
vation, been able to verify, having taken females during
all periods of the year with these appendages fully de-
veloped. They are absent on the young females. We
believe, however, that, when they are once developed,
they continue permanent organs, only disappearing as the
result of accident.

In the Anceide, the incubatory pouch appears to belong
to the three posterior segments of the pereion. By the
continued growth of the ova, the pereion is reduced to a
most impoverished state. The alimentary canal being in
a collapsed condition, and always empty, the animal can
only be viewed in the light of a great egg-producer, after
the development of which an empty sac only is left, the
poor remains of a worn-out animal.

The history of the development of the ovum from
its impregnation to the development of the perfect larva
has been best worked out by Valette St. George in
the Amphipoda, and Anton Dohrn in the Isopoda. We
must refer the student to the memoirs of these two
authors for a detailed account of the germination and
erowth of the ovum in all its stages. It will suffice for
us to say, that it appears to be clearly established by

xliv INTRODUCTION.

all observers, that in the progressive growth of the ovum,
the embryo of the Amphipoda is rolled within the egg in
an opposite manner from that of the Isopoda. The latter
is folded backwards, so that the ventral appendages are
developed on the external surface, whereas the Amphipoda
is bent on itself, the ventral appendages being developed
on the inner surface. Dr. Fritz Miller states that, in
Tanais, one of our aberrant genera, the development of
the larva is after the manner of the Amphipoda, and not
of the Zsopoda, among which it is classified.

The length of time between the epoch of the deposi-
tion of the ovum in the incubatory pouch, and the period
of the emancipation of the young animal from the care of
the parent, is probably about six weeks. We have ob-
served that to be the time required in the genus Asellus,

At first the egg is perfectly round. It shortly after-
wards increases in one direction, becoming also somewhat
larger in Amphipoda at one extremity. Indistinct seg-
ments are now observable. The wall of the ovum is of
an elastic character, and yields to the movement of the
internal embryo.

Probably about the middle of the period of incubation
the embryo quits the egg, for we have constantly taken it
from the pouch in a very immature condition, without
being enclosed in the egg-case. The larva at this period
is very immature, and enclosed within a general tunic,
which, without having any apparent vital connection with
the animal more than the original egg-case had, adapts
itself in general form to the whole creature, and fulfils
the duty of a protective tissue. As the embryo increases
in dimensions and completeness of form, so the tunic cor-
responds in size and form. At length, freeing itself from
this case, the larva strengthens in its own development,
but does not immediately quit the care of the parent.

INTRODUCTION. xlv

_We have frequently observed the young Talitrus escape
from the mother, upon the capture of the latter; and
from the active state of their existence at this time, they
appear as if they had long been capable of so acting, if
they had required it. The observation of Dr. Salter on
the common Gammarus, detailed at page 380 of the first
volume of this work, fully confirm this fact—as does the
circumstance that the young of Arcturus are protected by
the mother, who supports and carries them about on the
antennze. Also we have been able to corroborate the
observation of Mr. H. Goodsir, that the Caprella carries
about its young attached to its body. These, together
with the fact that many genera, particularly of the
Podoceride, protect and nurse their young for some time
within nests, which they build apparently for no other
purpose, afford abundant proof that in these animals
there is a conscious love of offspring that appears to
be less marked in animals far higher in the scale of
scientific classification.

When the young of Gammarus first swims about as a
free animal, it only resembles the parent in a modified
degree. The antenne show no distinction between the
peduncle and the flagellum. The latter is shorter, and
consists of but five articuli, while thirty to forty may be
present in the parent. This relative proportion is visible
also in the lower antennze, and in the secondary appen-
dage of the upper, which increases with advancing age,
until the adult stage is acquired.

In the structure of the eye we see the same gradual
increase going on after the animal has become free. The
lenses in the young are from ten to twelve in number,
whereas, in the adult, from sixty to eighty may be counted.
In many genera it also changes its colour, as does also
that of the animal itself.

xlvi INTRODUCTION.

The young are generally white, or of a deep orange
colour; in the adult, the colours vary apparently in rela-
tion to the presence of light and other surrounding cir-
cumstances. Occasionally the males vary in colour from
the females. We see in Orchestia a rosy tint frequently
ornamenting the great claw, and some other parts. We
have also observed in Amphithoé littorea the well-
matured males assume a yellowish appearance. This may
also be the case in other genera of which we have not had
the opportunity of exact observation.

In Orchestia, the second hand in the larva bears a near
resemblance in form to the same appendage in the female
—a fact that is, we believe, consistent throughout the
entire class. The warty development of one of the pos-
terior legs also increases with age.

In Hyperia, the larva bears but little resemblance to
the parent. This was first pointed out by M. Milne
Edwards, and next by Mr. Gosse. But more extended
observations of the forms of these young animals were
detailed by us in a memoir published in the “ Annals of
Natural History for 1861,” on some exotic species. Our
observations on the larvee of the parasitic Jsopods show
a wonderful similarity between the larve of families in
distantly separated orders.

NERVOUS SYSTEM.

The nervous system was first made out in a general
memoir on the subject by MM. Milne Edwards and An-
douin. The observations of these authors have since been
generally verified by HH. Loven and Bruzelius in the
Amphipoda, and Lereboullet in the terrestrial Lsopoda.
We have also carefully dissected out most of the system
in both the genera Talitrus among the Amphipoda, and
Ligia among the Isopoda. The plan of the nervous

INTRODUCTION. xlvil

system in these two orders is that of a typical crustacean.
A ganglion corresponds to every segment of the animal;
those belonging to the organs purely of sensation being
amalgamated together into a cephalic lobe. This is very
beautifully shown by HH. Loven and Bruzelius (Bidrag
till Kannedomen om Amphipodernas inre byggnad *).

very ganglion of the several segments after the head
is united to the others by two parallel cords in the
Amphipoda, and one in the Jsopoda, although in the
genus Ligia we distinctly made out two, as in the Amphi-
poda : from each ganglion, on the right and left, is given
off two main branches, and in Ligia we observed two
other less important threads. These supply the legs and
internal viscera. From the cords, about midway between
each ganglion, branches off, on the external side of each,
a single branch, which in the Oniscide M. Lereboullet
places nearer to the preceding ganglion. In the Amphi-
poda, we found it rather nearer to the succeeding ganglion.
In Ligia, it appears to be just midway between the two,
from the base of which, both before and behind, spring
other thread-like branches.

The diagrams of the arrangement of the caudal supply
of nerves, given in the memoir of Lereboullet, differ from
that given by M. Milne Edwards in his “ Histoire des
Crustacés.” The latter author figures a distinct ganglion
to each of the caudal segments, illustrating his view from
observations on Cymothoé, in which the six segments are
separate, while Lereboullet illustrates the caudal ganglia
as being consolidated into a single mass, from which
numerous threads are sent back to the extremity of the
animal. Moreover, this author only figures six separate
ganglia after the cephalic mass, which would make (even
allowing the oral appendages to be supplied with small
filaments of nerves, instead of branches springing from

* Ofversigt af Kongl. Vetenskaps-Akademiens Férhandlingar, Jan. 1859.

xlviil INTRODUCTION.

a well-developed ganglion), the seventh segment of the
pereion to have its ganglion consolidated with those that
supply the caudal region—a view that our own observations
lead us to believe has been founded on a misconception.

GEOGRAPHICAL DIsTRIBUTION.

The Geographical Distribution of the two orders of the
Sessile-eyed Crustacea, if made under careful and extensive
observations, would (from the great amount of the modifi-
cation of parts, while a close assimilation of general form is
very persistent throughout great numbers of genera) afford
one of the most interesting and, we believe, instructive
chapters in the distribution of life over the globe.

The subject has not yet sufficiently been worked out
so as to approximate to correct information ; for so much
of the earth’s surface has yet to be searched, that it is by
no means improbable that new and intermediate forms
may frequently be found in places that are yet unknown,
so that forms that as yet are described as species or genera
may be only modified forms of one species, or, as has been
demonstrated by M. Hesse with respect to Anceus and Pra-
niza, that animals placed by authors in separate genera
and in distinct families may be only sexually distinct.

Such imperfect information as is at our command,
while it does not enable us to grasp the subject so as to
do justice to it as a whole, has yet enabled us to observe
some points of interest that our British species possess in
relation to exotic forms.

With the exception of a single specimen, brought from
Algiers by M. Lucas, the genus Jalitrus is only known as an
inhabitant of the northern and western coasts of Europe,
while its closely allied form, Orchestia, and its congeners,
excepting Nicea, of which we know but one or two species
(which tend to corroborate the assertion), appears to be

INTRODUCTION. xlix

very abundantly scattered over the whole world. Like
Talitrus, Orchestia lives out of the sea, choosing moist
places, but not burrowing a habitat for itself as Talitrus
does. With us, Orchestia lives within the reach of the
spray of the sea; but some species in the Southern Hemi-
sphere live many miles inland, choosing terrestrial plants
for their abode, sometimes at an elevation of fifteen hundred
feet above the level of the sea. In these specimens the
males, and, we believe, the males only, have some one
or other of the joints of one of the posterior pairs of legs
developed into a large internally concave scale, which, we
believe, assists in retaining moisture, so that the branchial
sacs may not suffer from desiccation.

The genus Montagua appears to be wholly confined to
the northern temperate latitudes, the species gradually
diminishing in size as they approach the warmer seas.
The close assimilation of this with Stegocephalus and
Pleustes of the colder latitudes, is shown by the inter-
change of certain parts in their structure. In Montagua,
the superior antennze have no secondary appendage,
neither have the mandibles a palpiform one, and the
posterior pair of pleopoda terminate in a single ramus.
Pleustes resembles Montagua in the former characteristics,
but has the posterior pair of pleopoda terminating in two
rami. Stegocephalus resembles Pleustes in its charac-
teristics, but it has a rudimentary appendage on the
superior antenne. We have little doubt but that the
others have also such an appendage in the larval con-
dition, since it is a common feature in young Amphi-
poda. Stenothoé,in the Southern Hemisphere, represents
the Stegocephalide in the Northern, and agrees with
Montagua in all important characters; it differs in having
avery large hand to the second pair of gnathopoda,—a
doubtful generic character, in our estimation.

d

INTRODUCTION.

The genera of the sub-family Lystanasstna appear to
be very generally diffused over the entire globe, increasing
in dimensions in those species that approach nearer to the
Arctic and Antarctic latitudes, in some instances reaching
to the largest known of the order, equalling three inches
in length, as may be seen in Lysianassa Magellanica, from
the Straits of Magellan, and L. gryllus, from Spitzbergen.
These two so closely resemble one another, that they can-
not be characteristically distinguished.

The genus Ampelisca, and its near ally Haploops, we
only know as belonging to the Northern Hemisphere, but
in that region extending from Japan to Europe, from
Greenland to North Carolina on the coast of America,
and in Europe to the Mediterranean Sea.

In the sub-family PHoxina all the genera but one are
only known in the north temperate region, but with a
widely diffused area, extending from Japan to Europe.
One species of the genus Gdiceros has been taken in New
Zealand, and one of Iphimedia in Terra del Fuego. Of
the former we have our doubts in its relation to the
genus; the latter has a very near resemblance to J. Hdlane
of Europe. Most of the genera of this sub-family are
burrowers in mud or sand. J/sea dwells, without being
parasitic, on the back of hairy crabs, and the only
specimens of Darwinia, that have been taken alive, were
found adhering to the throat of a cod-fish. The genus
Sulcator lives cn sandy shores, making tracts along the
margin of the sea, somewhat similar to those found in
older slate and sandy rocks; and it may be interesting
to remember that we have attributed to this sub-family
the only Amphipod that has been hitherto discovered as
fossil, the Prosoponiscus problemaiicus of the magnesian
limestone of Durham, and Zechstein-dolomite of Glicks-
brun.

INTRODUCTION, hi

The family of Gammarip# belongs to the Arctic and
north temperate zones. With but few exceptions of the
closely allied congeners Dexamine and Atylus, which
consist together of twenty-one species, we know of only
one taken, near Valparaiso: all the rest are northern
species. Of the genus dora but two species are known;
one from the British seas, the other from the western
coast of South America (Valparaiso). Judging from the
figures in Gay’s “ Hist. de Chile,” the resemblance of the
two species is remarkably close, an apparently useless
tooth on the anterior margin of the first pair of legs
of the southern form alone distinguishing it from the
northern.

The subterranean fresh-water genus Niphargus, which
lives generally in closed pump-wells in England and
many parts of Europe, has its nearest congener in
Eriopus, from the deep sea off Bohusia. Judging by the
figure given by Bruzelius, there is little that distinguishes
one genus from the other; and it is highly probable that
Gammarus pungens, from the warm springs of Italy, is
also a species of Niphargus. Of the two species of Cran-
gonyx, another fresh-water subterranean genus, one is
found in England, the other in Kamschatka, and these
bear avery close resemblance to the female form of the
marine Gammarella, a genus, though only having three
species, found in the European seas, as well as on the
South American coast and at Pitt’s Island. Species of the
genus Melita have been taken in European, Brazilian, and
Indian seas, and Mera extends all over the temperate zones
of both Northern and Southern Hemispheres. 'The genus
Amathia is essentially an Arctic form, the species losing
their size and spinose character as they approach the
temperate seas. No species has been recorded south of
the English Channel, while a species found on the Crimean

hi INTRODUCTION.

shores of the Black Sea is as large and well developed
as the Arctic specimens. From Pondicherry, also, a
specimen is recorded that closely resembles the large
specimens of the northern type.

The genus Gammarus, even as we have restricted it,
contains between forty and fifty species, all of which are
Arctic and north temperate, and extends round the globe,
except one taken at Jamaica, another at New Holland.
Fresh-water species of the geuus inhabit the rivers and
streams of Europe and North America. Megamera, a
near congener of Gammarus, has the largest and most
spinose species in the northern regions, while others are
found at Peru, Borneo, and the Zooloo seas.

The genus Amphitoé contains between thirty and forty
species, and is very universally spread over the globe,
species having been taken in the Arctic seas and all round
the coast of Europe, in the Black Sea, and the Medi-
terranean ; they have been found at the Cape of Good
Hope, and on the eastern and western coasts of South
America, ou the Australian shores, as well as in Zooloo
and Japanese seas, in the islands of the Pacific and
Atlantic Oceans, also on the weed in the Saragossa Sea,
of the Atlantic, and on floating plants in the Pacific ; and
one species is recorded from the fresh-water marshes of
South Carolina.

Podocerus is mostly northern, extending, however,
down the coasts of Europe and America. One species is
recorded by Dana from the Bay of Sunda, and another
from the shores of Brazil.

Cerapus, including its female, Leucothoé, has a wide
range, species having been taken on the European and
North American shores, on the eastern coast of South
America, and in the Indian and Zooloo seas, while its
near ally, Siphonecetus, has only been found on the north-

INTRODUCTION. hii

western shores of Europe. The genus Nenia, all the
species of which are closely allied in form, has only been
recorded from the British shores. Four species of Cyr-
tophium have been discovered, one of which is from the
Hast Indies, one from Rio Janeiro, and two from the north-
west of Europe. Corophium, so abundant when found,
has been taken on the western shores of Europe, the
Mediterranean, on the coasts of Japan and Brazil. It
burrows in mud; but there is reason to doubt either that
it preys on the Annelids or migrates at particular seasons.

That terrible wood-destroyer, Chelura, so devastating to
the piles and submarine timber all round the shores of
Europe, has not been recorded from other lands.

We have generally looked upon the Hyperina as pelagic
species; but recently it has been pointed out by Mr.
Edward, that some of our British genera burrow into and
hide themselves in sand on the shores of the Moray Firth.
The two British species of Hyperia (which we have great
reason to believe to be but one, being male and female),
have an extensive geographical range, from Greenland to
Cape Horn, from Rio to the Zooloo seas.

Vibilia has apparently an equally extensive range,
though fewer species have been determined. Themisto,
also, has been recorded from Greenland to sixty-three
degrees south latitude in the Atlantic Ocean, while species
of Phronima have been taken as far north as the Shet-
lands, as well as in the Atlantic, at Naples, and at
Borneo. The Caprellide appear to be very universally
and abundantly diffused. The very close resemblance
of the species from very distant and opposite localities
is suggestive of a close affinity in the respective forms.
Specimens from Japan, and the eastern coast of North
America, are not appreciably distinct from others found
on the eastern coast of South America, as well as on our
English coast ; and when we take into consideration the

liv INTRODUCTION.

changes in the forms that the animals of this genus
undergo in their growth to an adult state, it is not im-
probable that immature specimens may be misinterpreted
for adult varieties. Cyamus lives parasitically on the
whale, and probably thrives on no other animal. The
one or two solitary specimens that have been found
attached to the dolphin are probably young creatures that
have strayed from their natural habitat.

The genera of Isopoda appear to be more generally
diffused throughout the various regions of the sea; and
from the various distant localities in which that species
have been found, some may be inclined to think that
they are universally distributed.

The genus Tanais has been found on the coasts of
North-Western Europe, Brazil, in the Zooloo and Feejee
seas, as well as on the western coast of North America ;
and equally varied have been the recorded habitats of the
nearly allied genera, Paratanais and Leptochelia, which
latter Fritz Miller believes to be the male of Tanais.
The near ally, Apseudes, is only known in Europe and
Egypt, where but few specimens of two closely resem-
bling species have been found. The genera Anthura and
Paranthura are also sparsely represented, both in the
species and specimens. They have been taken on the
southern and western coasts of Europe, at New Zealand,
the Mauritius, and the Cape of Good Hope, as well as on
the eastern coast of North America. Of the genus Anceus,
of which eleven species have been determined on the
north-west coast of France, by M. Hesse, three at most
are known to the rest of Europe, and but a single species
to the eastern coast of North America.

The Bopyride are tolerably abundant in the temperate
regions, but few in the more tropical or Arctic latitudes,
the genera confining themselves with considerable exacti-
tude to peculiar species of Crustacea. Thus we have failed

INTRODUCTION. lv

to detect Cryptothiria, which we have found to be tolerably
abundant in the genus Balanus, in Cthamalus, whose
habits and general appearance are so closely allied to it.

The several genera of the family Agide are animals
peculiarly belonging to the temperate seas, and adequately
represent the Cymothoide of the torrid zone. It is
remarkable that, being parasitic upon fishes, no species of
the latter family has been hitherto detected on our own
coasts,

The Asellide flourish chiefly in the temperate regions
of the seas, being scarcely represented in the frigid zones,
and not at all in the torrid.

Arcturus is peculiarly an Isopod of the colder zones,
where its species grow to the greatest dimensions in both
the northern and southern seas; but a single specimen
has been taken in the torrid zone, in thirty-one fathoms
of water, north of Borneo. The Jdoteide flourish every-
where, the largest specimens being in the Baltic Sea and
near Cape Horn. They live amongst the weed, either
fixed or floating, and species have been often taken
swimming free in mid-ocean, where they assume, as
Crustacea under the same condition frequently do, a deep
indigo-blue colour. The Spheromide are a family that
are very littoral in their habits; they range from the
equatorial latitudes to the colder regions of the temperate
zones, but die out before reaching the Arctic and Antarctic
isothermal lines. In hotter latitudes, some species, in
their depredations on submarine timber, take the place of
Limnoria, a genus of the Asellide, and surpass it in the
extent of their capability of injuring submerged wood.

Ligia, and the other terrestrial genera, appear to find
their home best in the temperate latitudes, but live from
the equator to within a short distance of the frigid
climate.

These few observations, imperfect as they naturally

lvi INTRODUCTION.

must be, demonstrate, we think, the great amount of
interesting information that a more complete study of the
subject must elucidate. (C. S. B.)

As the information conveyed in the following letter reached us too late to appear
in the Appendix, we think it but just to the author to publish it entire; the
more so since, during the progress of his researches, we repeated them and know
their accuracy. :

My DEAR SPENCE Bate,

You are kind enough to ask me for a short abstract of my investiga-
tions in the anatomy of Anceidze which I tried to make when staying with you
in Plymouth. I am the more glad to follow your request, since it is especially
your Memoir upon these animals that made me desirous to work on them. You
were quite right in directing the attention of observers to the internal structure
of these little Crustacea, for there are some points in their organization which were
not followed up by Mr. Hesse in his elaborate Memoir, and some points in which,
your opinion differing from that of the French naturalist, we had no certainty
about their real nature.

I do not think that you are right in speaking of an early distinction between the
male and female Anceus. There is no doubt that the outward aspect of some of
the little Pranizee, just having left the parent, makes more the impression that they
are to become Anceus, whilst others resemble more the female, or Praniza form.
But in giving special attention to that point, I found that this impression was
only due to the expansion of the segments of the pereion being greater or smaller
than to any real difference. Besides that, I kept some animals, which had rather the
aspect of females than males, during some time in a glass, and had the opportunity
of watching their moult. Two of them enabled me to see the large projecting
mandibles of the males within the head of what I thought was afemale. [examined
immediately the sexual parts of the specimen, and found a well-developed penis on
the last exceedingly small segment of the pereion. There can be no doubt, therefore,
that Praniza changes into Anceus.*

This is what Mr. Hesse contended. But though I must agree with him in this, I
cannot but have another interpretation regarding the so-called larval or Praniza state.
Mr. Hesse says, that only the Anceus state is the adult state, and that, ‘‘quelques
jours avant la transformation des Pranizes fémelles en Ancées les ceufs qui préexistent
s’apercoivent a travers la peau,” &c. In calling the eggs pre-existent, he is not, it
appears to me, justified, for they make their appearance very soon, and begin their
devolopment in animals which are far from the Anceus period, which Mr. Hesse calls
their Anceus state. I agree, on the contrary, fully with you in calling the adult or
Anceus state one of a retrograde character, for every organ begins then to degene-
rate.

Regarding the digestive apparatus, my investigations have led me to other results
than your remarks seem to show. I could observe the mouth and the whole intes-
tine in the old males as well as females. Those sacs, filled with green mass, are the
liver sacs, as the study of their embryology clearly states. The embryology clearly
indicates the Isopodous nature of the family ; but I must say that I never found, nor
expected to find, such forms as Mr. Hesse figures with a central red eye. There
certainly must be an error in his drawings.

There is another puzzling circumstance regarding the conformation of the seg-
ments. In the adult there seems to be the want of one of the typical segments, and
you consider it to be either the first or second segment of the pereion. But my
embryological investigations show that all the typical segments are present, as in
other Isopoda. Im the very early state of the embryo you will find two pairs of
antennee, one pair of mandibles, two pairs of maxillz,and seven pairs of feet. Every
one of these extremities corresponds with a segmental division of the body. But
there is between the last pair of the pereiopoda and the first pair of pleopoda a
segment whose extremities are wanting. This segment afterwards constitutes a
very small portion of the pereion, and is rather easy to be overlooked; in the male
the penis is fastened to it. Counting that segment, you will find there is none
wanting in the composition of the body; and you can be quite sure in calling the
first pair of the legs of the embryo the maxilliped, and the second the gnathopod,
for both are connected with the mouth in a very early state already.

I could add some more particulars about the internal structure of the animal, but
it would hardly be of much use without adding plates to what I have to say.
What I have already stated will, however, show, that though there are some
anomalies about the Anceide, they are not of such extent as formerly was believed.
I hope, besides, to give a complete account of my investigations in a short time in
one of our German periodicals. Yours &e.,

Messina, October, 1868. ANTON DOHRN.

* It must not be forgotten, with reference to this too general expression, that it is only the male
individuals (having in the young state the form of Praniza) which ure transformed intu the Anceus
state; the females retaining their preceding form of Praniza. Teor

BRITISH
SESSILE-EYED CRUSTACEA.

Order—AMPHIPODA.
Group—NORMALIA.
Division—HY PERINA.

In this Diviston the eyes are generally developed to
an abnormal size, often nearly occupying the whole
surface of the head. ‘The antenne are frequently absent,
or, when present, more or less abnormal in their form,
rarely ending in a multiarticulate flagellum. The ap-
pendages of the mouth are rudimentary or obsolete.
The arms are small and less powerful than the walk-
ing legs, varying in different families from the simple
to the complexly-chelate form. The body has the
segments generally separate, although in some genera,
as Phrosina, of which we have no British example
recorded, the first two are fused together. The tail also
has the segments usually distinct, but in some exotic
genera, as Pronvé, Brachyscelus, &c., the fifth and sixth
segments are incorporated into one. The appendages
are more liable to aberration than in the Gammaride.
The animals are remarkable for the paucity of hairs that
exist upon their integumentary tissues, and are, for the
most part, parasitic in their habits, attaching themselves
to fishes or medusze; they are able, however, to swim
with ease.

VOL. I. B

2 HYPERINA.

This division is synonymous with Milne Edwards’s
family of Hyprrines, and also with Dana’s family of
Hyperipea. It contains four families, two only of
which have representatives in our British Fauna, namely,
Hypreriip& and PHRONIMID&.

Fam. I.—HYPERIIDA.

The head is large and globular, being nearly occupied
by the eyes. The superior antennz consist of a three-
jointed peduncle and a flagellum, variable in length, but
of which the first articulus is very long. The inferior
antennze are formed of a peduncle and a variable flagel-
lum. The first two pairs of legs are simple, but have
the wrists more or less infero-anteriorly produced ; the
other legs are generally subequal in size. The three
anterior pairs of swimming legs resemble those of
Gammarus, but the three posterior are broad, flat, and
biramose ; the rami being lanceolate, and frequently
serrated, but destitute of any ciliary fringe.

The species are oceanic in their habits, and found to
exist only in the gill cavities of the medusz.

LESTRIGONUS, 3

AMPHIPODA. HYPERIUDA.
HYPERINA.

Genus—LESTRIGONUS. (Edwards.)

Lestrigonus. Mriunt Epwarps, Ann. des Sci. Nat. xx. p. 392. Hist. des
Crust. iii. p. 81. Dana, U.S. Explor. Exped. p. 982.
Spence Bartz, Cat. Amph. Brit. Mus. p. 287.

Generic character. Cephalon orbicular, deeper than broad.
Segments of the pereion short, three times as deep as long.
Pleon longer than the pereion ; first three segments long and the
three posterior short. Eyes large, occupying the entire lateral
walls of the cephalon. Antenne long, subequal, terminating
in multiarticulate flagella. Mandibles having a triarticulate
appendage. Gnathopoda complexly subchelate. ‘Telson single,
squamiform, triangular.

Tue head is large and rounded. ‘The segments of the
body are short, while those of the tail are much longer,
the three anterior being the longest. The eyes are very
large and occupy the whole of the lateral walls of the
head, meeting nearly at the top and considerably en-
croaching upon the facial surface. The antenne are
of the same length, and are generally very long, never
being shorter than the depth of the head and always
terminating in a multiarticulate flagellum, the first
articulus of which is very long, apparently consisting of
several articuli fused together. The mandibles are
furnished with a three-jointed appendage. The first
two pairs of legs have the wrists infero-anteriorly pro-
duced to a sharp angle; the hand is narrow and the
finger short and sharp, which, being capable of closing
against the produced point of the wrist, forms with it
a completely subchelate organ, very characteristic of the

B 2

4 HYPERIID®.

whole of this division of Amphipod Crustacea. The
walking legs are nearly of similar length, but have the
coxe, especially of the two anterior pairs, not so deep
as in the Gammarina, and the thighs less broadly de-
veloped. The natatory appendages possess no con-
spicuous distinction from other Amphwoda, but the three
caudal pairs have the peduncles broad and flat, and the
rami sharp and triangular. The middle piece is small,
triangular, and squamiform.

The geographical distribution of this genus appears
to be world-wide, since it has been observed in the
Atlantic as well as the Indian and Pacific Oceans, from
the arctic to the tropical latitudes.

LESTRIGONUS EXULANS. 5

AMPHIPODA. AYPERIID.
HYPERINA.

LESTRIGONUS EXULANS.

Specific character. Antenne reaching only to the third or fourth segment
of the pereion ; inferior pair haying the last joint of the peduncle termi-
nating inferiorly in a small tooth or point. Propodos of each pair of gnatho-
poda serrated.

Lestrigonus exulans. Kroyer, Gronl, Amfip. p. 68, pl. iv. f. 18, a, 6, ¢,
Epwarps, Hist. des Crust. t. iii. p. 82. Spence
Bats, Cat. Amph. Brit. Mus. p. 287, pl. xlviii.
fig. 2.

Tue head is oval, the vertical being the longer axis.
The eyes are large, and occupy the entire lateral walls of
the head. The antennez are nearly of equal length, and
reach to about the third or fourth segment of the body,
The superior pair are rather longer than the inferior, and
have the first articulus of the flagellum longer than the

6 HYPERIIDA.

peduncle; the remainder being very short, the basal ones
being shorter than broad. The inferior pair have the last
joint of the peduncle nearly as wide at the distal extre-
mity as at the base, and terminating inferiorly in a strong
tooth. The flagellum is suddenly narrower, and after
the first articulus consists of several short articuli. The
mandibles are broad and short, not terminating in teeth,
or a sharp cutting blade. The molar denticle consists of
a flat plate, furnished with a thick down of hair. The
appendage has three joints ; the first extremely short, the
others being equal, and the last terminating in a sharp
point ; the whole being remarkably free from hairs. The
first two pairs of legs are very small and sub-equal; the
first pair have the metacarpal joint and wrist inferiorly
produced, and tipped with several stiff spines. The hand
is narrow and tapering ; the inferior margin serrated, the
serrature consisting of a series of rather long teeth, asso-
ciated in groups of three, the longest in each group being
the most anterior. The finger is slightly curved, and
armed upon the inner margin with a serrature similar in
character, but less regular in feature, to that of the pre-
ceding joint. The second pair of legs much resemble
the first, but have the wrist rather more infero-anteriorly
produced. The hand is a little longer, and has the
armature upon the inferior margin, as well as that of the
finger, less distinctly marked. The other legs are nearly
of equal length. The caudal appendages vary in length ;
the penultimate pair being considerably the shortest,
while the last are the broadest and longest, and have the
inner ramus, as well as the inner margin of the outer
ramus, freely serrated. The middle tail-piece is ovately
lanceolate.

The antennze in our British specimens are slightly
longer than represented in Kroyer’s figure of the type.

LESTRIGONUS EXULANS. a

We also observe that the peduncle of the second pair of
antennz is not so decidedly truncate as in ours; but, in
spite of these differences, which are probably due to the
delineator, we believe that our British form is identical
with that of Kréyer’s arctic specimen.

The original specimen was taken by Kroyer in Green-
land. British specimens have been sent to us from
Carrickfergus, where they were found by Professor
Kinahan, to whom we are indebted for the first British
specimen; from Cumbrae, where they were obtained by
Mr. Robertson; and they have been recently sent to us
from Banff, where they were taken by Mr. Edward.

The resemblance between this species and L. Gaudi-
chaudiu from Chili is very close, but the two species can
be readily distinguished by the character of the armature
on the hands of the first two pairs of legs.

8 HYPERIID®.

AMPHIPODA. HYPERIIDA.
HYPLRINA.

LESTRIGONUS KINAHANI.

Specific character. Antennz subequal; the superior being rather the longer,
equally the entire length of the animal.

Length 3 inch.

Lestrigonus Kinahani. Spence Bats, Cat. Amph. Brit. Mus. p. 289,
pl. xlvili. fig. 4.

Tue resemblance between this species and Lestrigonus
exulans is remarkably close; so much so, that should the
animals of either species lose their antenne, we believe
that the most acute observation would not be able to
detect any distinguishing feature.

The antenne are rather longer than the animal, being
nearly of equal length; the upper are, however, some-
what the longer. The peduncle of the superior pair is as
long as the head, the first joint being longer than the two
others. The first articulus of the flagellum is longer
than the peduncle, tapering gradually to the extremity,
and having the inferior margin fringed with hairs. The
flagellum is very long and very slender, the articuli
being about four or five times as long as broad, with the
exception of a few succeeding the first long articulus.

LESTRIGONUS KINAHANT, 9

The inferior pair have the peduncle reaching beyond that
of the superior, and terminating abruptly, the flagellum
being considerably narrower, and somewhat shorter, than
that of the upper pair, although the articuli are similarly
formed to those of the superior. In all other respects—
except, perhaps, in the less unequal length of the caudal
appendages—the description of ZL. exulans will suffice for
this species also.

The near resemblance of this species with that of L.
Fabric (M. Edw.) of the Indian Ocean and L. rubescens
(Dana) of the Pacific, is quite as remarkable as that exist-
ing between L. exulans and a species from Chili.

The first specimen which we received was sent to us by
Professor Kinahan, who captured it off Carrickfergus,
and in compliment to whom we have named the species.*
We have since received it in considerable numbers from
Mr. Edward, of Banff.

The colour, as far as we can judge from the dead ani-
mals, is that of a salmon tint, with a few small spots of
dull red. The eyes are probably green.

* Tt is with much regret that we learn, while this sheet is passing through
the press, that this able carcinologist has, at an early age, departed this life.

10 HYPERIIDA.

AMPHIPODA. HAYPERUD.
HEPERINA.

Genus—HYPERIA. (Latreille.)

Hyperia. LAtTREILLE, in DusmArust’s Consid. sur Crust. p. 258, 1825.
Minne Epwarps, Ann. des Sci. Nat. xx. p. 387. Hist. des
Crust. t. iii. p. 74. Dana, U.S. Explor. Exped. p. 986.
Spence Barz, Cat. Amph. Brit. Mus. p. 292.

Metoechus. Kroyer, Grénl. Amfip. p. 60. Murine Epwarps, Hist. des
Crust. iii. p. 78.

Tauria. Dawa, U. 8S. Explor. Exped. p. 988.

Hiella, Strauss, Mém. du Muséum t. xviii.

Generic character. Cephalon large, orbicular. Eyes large,
occupying most of the lateral, and encroaching upon the frontal,
walls of the head. Antenne short, subequal. Gnathopoda
nearly alike, small; first pair nearly simple, the second complexly
subchelate. Pereiopoda subequal. ‘Three posterior pairs of
pleopoda biramose. ‘Telson squamiform.

Tue head is large and rounded. The body is broad
and convex. The eyes occupy the greater portion of
the lateral and dorsal walls, and encroach upon the
frontal surface of the head. The antennez are short,
being never longer than the depth of the head, and nearly
equal in length. The lower pair are inserted at a consi-
derable distance from the upper. The arms are small
and imperfectly prehensile, but formed upon the com-
plex type so generally prevailing in this division of
Amphipoda. The walking legs are nearly of similar
length, and tolerably strong. The caudal appendages
are biramose, and the middle piece consists of a small
lanceolate scale.

Dana has, we think correctly, associated the genus
Meroecuus of Kréyer with the present, from which it

HYPERIA. 11

only differs in the infero-anterior angle of the carpus
being more strongly developed. Mr. Spence Bate
has also, in the Catalogue of Amphipoda of the
British Museum, incorporated Dana’s genus Tauria for
a similar reason—namely, that the wrists are only de-
veloped to a very small degree. In the same work
Mr. S. Bate has also suggested that the species of the
present genus are but the females of those of Lestrigonus.
He arrived at this conclusion after examining a consider-
able number of species of both genera, finding that it is
difficult, if not impossible, to assert (with reference to
the structure of the antenna) where one genus com-
mences and the other ends. Recently, through the
kindness of Mr. Edward, of Banff, we have had the
opportunity of examining many fresh specimens both
of Lestrigonus and Hyperia, from the same locality, and
we found that all the adult Hyperie of which the sex
could be detected were females, but that none of the
Lestrigoni were of that sex.

12 HYPERIDA.

AMPHIPODA. HYPERIID.
HYPERINA.

HYPERIA GALBA.

Specific character. Cephalon large ; pereion distended ; pleon compressed.
Antenne short, having the flagella terminating in a few scarcely-visible
articuli. First pair of gnathopoda having the carpus broad, but not obliquely
produced; second pair having the carpus infero-anteriorly produced.
Peduncle of the posterior pair of pleopoda reaching to the apex of the rami
of the preceding pair. Telson lanceolate.

Length 4 inch.

Hyperia Galba. Monrtaau, Linn. Trans. xi. p. 4, pl. 2, fig. 2.
Minnt Epwarps, Hist. des Crust. iii. p. 77.
W. Tuompson, Ann. Nat. Hist. xx. p. 244.
Wuirtr, Cat. Crust. Brit. Mus. 1847 and 1850,
p. 57. Hist. Brit. Crust. p. 206. Goss, Mar.
Zool. p. 139. Spence Bars, Ann. Nat. Hist.
2 ser. xix. p. 150. Cat. Amph. Brit. Mus. p. 293,
pl. xlviii. fig. 9.

Hyperia Latreillia. Mitne Epwarps, Ann. des Sci. Nat. xx. p. 388,
pl. xi. fig. 1-7. Hist. des Crust. iii. p. 76.
Régne An, (Ed. Crochard) Crust. pl. lviii. fig. 1.

HYPERIA GALBA. 15

GuERIN, Icon. R. An. Crust. pl. xxv. fig. 5.
Wuirr, Cat. Crust. Brit. Mus. 1847 and 1850.
Hist. Brit. Crust. p. 206, pl. xi. fig. 3. Gosss,
Mar. Zool. p. 139, fig. 251.

Metoechus medusarum, Wuutte, Hist. Brit. Crust. p. 207.

Miella Orbignit. Strauss, Mém. du Muséum, vol. xviii. pl. 4.

Tue head is large and rounded. The body is very con-
siderably dilated, while the tail is much narrowed. The
eyes are large and occupy nearly the whole surface of
the head, distinguished by an exquisite soft tint of
green when the animal is alive. The superior antennz
consist of a short peduncle (the last two joints of which
are shorter than the first) and a flagellum, which is not
quite so long as the depth of the head; this flagellum
consists of a long articulus and a few faintly-marked
terminal articuli, but these appear to be either not con-
stant or only visible under treatment with liquor po-
tassee. The inferior antennz are scarcely as long as the
superior, and terminate in a flagellum nearly resembling
that just described. The terminal articuli are, therefore,
not to be depended upon as a specific character. The
arms are small, and differ but slightly; the second pair
have the hand somewhat the longer, and the wrist some-
what more infero-anteriorly developed than in the first
pair; both have the margin of the wrist fringed with
strong but not very sharp spines. ‘The walking legs are
nearly of one length, and tolerably robust. The caudal
appendages are broad and flat, and have the rami serrated
at the margins. ‘The peduncle of the last pair reaches
quite to the extremity of the preceding, and the middle
piece consists of a small lanceolate scale.

The colour of the species, except the green eyes, is
fawn, or faint yellow, passing into a salmon tint soon
after the animal is put into spirits; it is also dotted all
over with small specks of red.

14, HYPERIIDE.

We believe that Professor Milne Edwards was the first
to point out the great difference of form existing between
the young and the adult in this division of Amphipoda ;
but Mr. Gosse, in his pleasant “* Naturalist’s Rambles in
Devonshire,” has figured the young of this species. We
also have had an opportunity of examining them, a
drawing from which is given at figure -u * at the head of
this description. The head of the young animal is
small, and the eyes, consequently, are not much deve-
loped. The body is very large, while the tail is narrow
and straight, and lies compressed beneath the body. Mr.
Gosse has figured all the legs, but in our specimen two
pairs appeared to be wanting. This may be accounted
for by the circumstance that Mr. Gosse’s specimens were
older than ours, he having procured his as free and inde-
pendent creatures, whereas ours were procured direct
from the incubatory pouch. In the caudal appendages
there also appears to be a difference in the degree of
development as observed by Mr. Gosse and ourselves,
arising, no doubt, from the above-named cause.

This species, which must be considered as the type of
the genus, was first taken by Col. Montagu on the
southern coast of Devonshire, and it has been sent to us
from Jersey by Mr. George Parker. Specimens from a
Rhizostoma at Lamboy in Ireland have been communi-
cated to us in Mr. W. Thompson’s collection, belonging
to the Belfast Museum, and a number of specimens stated
to have been also captured in the stomach of a Medusa,
and given to us by the late lamented Rev. Professor
Henslow. Mr. White records it as inhabiting the pouches
of Rhizostoma Cuviert on the Dublin coast upon the autho-
rity of Mr. Hyndman. Mr. Edward has sent it to us from

* This mark is intended to symbolize the young animal.

HYPERIA GALBA. 15

Banff, and Professor Milne Edwards mentions having
found it on the shores of France.

Among several specimens sent to us from Banff, were a
few of a smaller size, which differed from the others in
having much shorter antennae, the inferior being the
shortest, and terminating in a more obtuse extremity than |
in the larger specimens. We were at first inclined to
describe them as a distinct species, but, all other condi-
tions being considered, we feel certain that they are
only immature specimens, a circumstance which induces
us to think that probably H. medusarum (Fabr.) of the
Arctic sea may likewise be but the young of this or some
other species.

The following vignette represents the little fishing vil-
lage of Polperro, in Cornwall, a place that has been
rendered attractive to naturalists as the scene of the la-
bours, as well as the residence, of Jonathan Couch, Esq.,

ES.

16 HYPERITD.&.

AMPHIPODA., AYPERIIDA,
AYPERINA.

HYPERIA OBLIVIA.

Specific character. Superior antenne as long as the depth of the cephalon ;
Inferior antenne longer than the superior and terminating in a multiarticu-
late flagellum. Gnathopoda subequal, carpi scarcely inferiorly produced.
First and second pereiopoda having the carpi considerably broader than the
propoda. Three posterior pairs of pereiopoda very long, subequal, and having
the anterior margins fringed with fine comb-like cilia.

Length 54 inch.

Hyperia oblivia. Kroyer, Gronl. Amfip. p. 70, pl. iv. fig. 19. Minne
Epwarps, Hist. des Crust. iii. p. 77. Spence Bare,
Ann. Nat. Hist. 2 ser. xix. p. 150. Cat. Amph.
Brit. Mus. p. 289, pl. xlix. fig. 5. Wurrn, Pop. Hist.
Brit. Crust. p. 206.

Tue head is deeper than long. The eyes are large,
but the pigment in our dead specimen formed a black
spot of distinct outline on the anterior edge of the

ewe

#!
.

HYPERIA OBLIVIA. i

lateral wall. The superior pair of antenne are about
as long as the head is deep. The peduncle is short; the
flagellum stout at the base, gradually tapering to the
apex, and is marked with a few imperfectly-defined rings.
The inferior antennz are more slender than the superior,
a little longer, and terminate in a multiarticulate
flagellum. The hands can scarcely be described as sub-
chelate, although they possess a tendency in the direction
common to most animals in the division. The third and
fourth pairs of legs are long, and have the wrists thicker
than any other joint; the hands are long and slender
and tipped with sharp fingers. The three succeeding
pairs are also uniform in shape, and nearly of equal
length, the last being rather the shortest; these have
the sixth joint remarkably long, and have the anterior
margin of each with the distal half fringed with short,
straight, evenly-planted cilia, and a few scattered longer
ones. The caudal appendages are rather long and
slender.

The colour of this species, if we can trust to that of
an animal that has been dead a short time, appears of a
light straw, having the back starred with a few spots of
black pigment.

We have frequently doubted whether this species
strictly belonged to the present genus. But finding that
it agreed very closely with H. trigona, of Dana, from
Cape Horn, we have considered it desirable that it
should remain therein for the present. The form of the
first two pairs of walking legs differ from the more
typical species. The two succeeding pairs of legs in
their length and armature suggest a relationship to the
genus Cyllopus, which is also supported by the form of
the inferior pair of antenne, but from that genus this

VOL. It. c

18 HYPERIID®.

species is excluded by the length of the last pair of
walking legs, which in Cyllopus are rudimentary.

This species was first taken by Kroyer, i Greenland,
from whence it is also recorded by Milne Edwards. The
specimen from which our description and figure are
taken was sent to us from the Moray Frith by the Rev.
Geo. Gordon, to whom we are indebted for the accom-
panying sketch, taken by Miss Gordon from a scene on
that Frith.

DOUBTFUL SPECIES. 19

DOUBTFUL SPECIES.

Tue Gammarus nolens, Johnston (Zool. Journ, iii. p.
179) has been referred to the present family, as a species
of the genus Typhis of Risso, without sufficient founda-
tion,* and probably in consequence of its supposed rela-
tionship to Montagua monoculoides, which was mistaken by
White and Gosse for a Typhis. Vide page 54. It is de-

scribed as about three or four lines lone

g, and not much

compressed. The antennez are not more than one-third the
length of the body, the superior pair being the shortest ;
the first and second pairs of legs monodactyle ; the first
with a small hand, the second with the hand more dilated;
the legs monodactyle and spinous; the two pairs of
caudal processes having mucronate branches, and the
middle tail-piece is simple, terminating in a_ papilla,
without any terminal processes.

It is described as not being rare near Berwick-upon-
Tweed, and as inhabiting conferve, but we have not

seen a specimen.

* Typhis nolens. Wurtr, Cat. Crust. Brit. Mus. p. 78. Spence Bats,
Ann. Nat. Hist. 2 ser. xix. p. 150. Rep. Brit. Assoc.
1860, p. 225.

Anonyx (2) nolens. Wurtr, Pop. Hist. Brit. Crust. p. 169.

20 PHRONIMID®.

Fam. Il.—PHRONIMID A.

INFERIOR antennz obsolete, in one sex at least. Organs
of the mouth rudimentary. Third pair of pereiopoda
developed more or less perfectly into a_ prehensile
organ.

This family corresponds with that of Dana, except
that it does not include the genus Phorcus. It is divided
into two sub-families, the PHronimipEs and PuHrost-
NIDES, the former only of which has, as yet, been included
in the Fauna of Great Britain.

Subfamily—PHRONIMIDES.

THREE posterior pairs of caudal appendages, biramose
rami lanceolate.

This subfamily corresponds with Dana’s division
PHRONIMINZ, exclusive of the genus Primno.

PHRONIMA, 21

AMPHIPODA. PHRONIMIDES.
HYPERINA.

Genus—PHRONIMA.

Phronima. Latrei.ie, Hist. Nat. Crust. et Ins. vi. p. 289. Spence Barr,
Cat. Amph. Brit. Mus. p. 316.

Phronyma. Lracu, in Sam. Ent. Comp. p. 101.

Phronoma. Srence Bate, Ann. Nat. Hist. 2 ser. xix. p. 150.

Generic character. Cephalon large, broadest at the top, and
gradually decreasing to the oral aperture. Eyes upon the
dorsal surface of the cephalon. Superior antenne imperfectly
developed. Inferior antenne obsolete. Mandibles without an
appendage. Pereion broad and flat. Guathopoda small; carpi
having the infero-anterior angles produced. Pereiopoda, con-
sisting of but six joints, third pair chelate. Pleon narrow.
Three posterior pairs of pleopoda biramose, lanceolate. 'Telson
small, single.

Tue head in this genus is much broader at the top
than at the mouth. The body is tolerably broad, and
the tail is very narrow. The eyes are large, and placed
upon the top of the head. The superior antenne are
but imperfectly developed, consisting only of two joints,
one probably representing the peduncle, the other the
flagellum, the latter armed along two-thirds of its distal
length with about sixteen long flattened filaments. The
inferior antennz appear to be altogether wanting. The
mandibles are without an appendage. The first two pairs
of legs are small, and have the wrists inferiorly produced,
and each terminates in a minute finger, flanked at the
base on each side by a small wing-like process, which Mr.
Spence Bate, in the Catalogue of the British Museum,
has named dactyloptera. The remaining legs only possess

22 PHRONIMIDA.

six joints in each, but which of the joints is missing
is difficult to determine. Observing, however, that the
finger in the first two pairs is reduced to a rudimentary
condition, and knowing the tendency in this division for
the wrist to assist in forming the prehensile condition of
the organ, we presume that the last joint is either wanting
or fused with the preceding. In one instance we have ob-
served a minute dactylos at the extremity of the second
pair of pereiopoda, but so minute that it was not ap-
preciable to less than 60 diameter magnifying power, and
it is most probable that it is absent from being generally
worn away. (We have a parallel instance in the allied
subfamily Phrosinides. In the genus Phrosina the num-
ber of joints is six, whereas in Primno it is seven. Five
joints of the legs resemble each other in the two genera,
but in Primno the finger is added to the extremity.)
The fourth pair of legs are very perfectly chelate. The
caudal appendages are biramose, the rami being short and
spear-shaped. The middle tail-piece is small, and slightly
emarginate at its extremity. The animals of this genus
are generally to be met with in tropical and subtropical
waters and the Mediterranean. The few specimens which
we know to have been met with in the Temperate Zone,
have been probably borne thither by various oceanic
currents.

PHRONIMA SEDENTARIA, 23

AMPHIPODA. PHRONIMIDES,
HYPERINA,

PHRONIMASEDENTARIA.

Specific character. Cheliform organ on the third pair of pereiopoda
slender. The inner margins of each ramus of the chela furnished with one
tubercle, both tubercles finely tuberculated.

Length 1 inch.

Cancer sedentarius. ForskAAat, Descript. Anim. Arab. p. 95.

Cancer (Gammarellus) sedentarius. Herrsst. Naturg. der Krabben, &c., ii.
pl. xxxvi. fig. 8.

Phronima sedentaria. LatrEILLE, Gen. Crust. et Ins. i. p. 56.
pl. ii. fig. 2. Hist. Nat. des Crust.
et Ins. vi. p. 289, pl. lvi. Lamanrcr,
Hist. des Anim. sans Vert. v. p. 197.
Leacu, Trans. Linn. Soe. xi. p. 355.
SAMOUELLE, Ent.Comp. p.101. Dzs-
MAREST, Cons. sur Crust. p. 257, pl.
xly. fig. 1 (after Risso). Minne
Epwarps, Ann. des Sci. Nat. xx.
p- 394; 2 ser. iii. pl. xiv. fig. 9,
Hist. des Crust. iii. p. 93, pl. x.
fig. 13. Cuvier, Régne Anim. 2nd
edit. v. (edit. Croch.) pl. Iviii. fig. 3.

24 PHRONIMID#.

Guerin Mén., Icon. R. An. Crust.
pl. xxv. fig. 4. Lucas, Expl. dans
Algérie, t. v. fig. 5. Wurrr, Cat.
Mus. Brit. Mus. 1847, p. 50. Pop.
Hist. Brit. Crust. p. 208, pl. xi.
fig. 4. Spence Bars, Ann. Nat.
Hist. 2 ser. xix. p. 152. Cat. Amph
Brit. Mus. p. 316, pl. L. fig. 1.

Tue head is deeper than long, tapering gradually
towards the mouth. The antenne are short, and almost
rudimentary, having but two joints, the basal one short,
the second about four times as long, furnished with several
membranous cilia along its distal portion. The upper lip
is a broad, thin plate, with a deep and narrow notch in
the middle. The mandibles consist of large and squami-
form plates, having the cutting margin formed into a
smooth hoe-like blade. The right blade is furnished with
a small second articulate plate, and both have the molar
process developed in the form of a flat plate, perpendicular
to the cutting margin, and fringed with short cilia. The
first pair of foot-jaws consist of a basal joint and two
branches, the one being somewhat lance-shaped and flat,
having the outer margin smooth, but the inner serrated ;
the teeth being curved anteriorly and slightly overlapping
each other. The second branch is hollow, or cup-shaped,
having the margin evenly pectinated. The second pair of
foot-jaws also consist of a basal joint and two ciliated
oval plates, pointed at the tips. The under lip also
consists of a basal joint, rather longer than wide, termi-
nated by two lateral pointed lobes, having a double row of
serratures on the inner margin, and furnished with a third
central acute inner lobe. The first two pairs of legs
are very similar, having the infero-anterior margin of
the wrist anteriorly serrated; and in the first it is a little
more produced anteriorly than in the second. The hand
is long, slender, cylindrical, and tapering. ‘The finger is

PHRONIMA SEDENTARIA. 25

short, terminating in a minute double point, and flanked on
each side at the base with two little wing-like appendages.
These are smooth and arcuated upon the upper margin,
but straight and regularly pectinated along the lower.
The next two pairs of legs are long and simple; the
succeeding pair are developed into the form of a perfect
claw, each branch having a tubercle near the base on
the inner edge, these tubercles being finely tuberculated ;
the last two pairs of legs are short and simple. The
natatory appendages are short, but havea robust peduncle.
The caudal appendages resemble each other, but the
penultimate pair are about half the length of the
others. They consist of a long, slender peduncle and a
couple of styliform branches. The middle tail-piece is
very small,

Dr. Pagenstecher, of Heidelberg, has published a very
interesting anatomical and physiological memoir on this
species in Wiegmann’s ‘ Archiv fir Naturgeschichte,”
for 1861, in which he has made us acquainted with the
early and intermediate states of the animal. In the
earliest condition the antenne are very small, dilated, and
jointless; the seven pairs of legs are of uniform size
and shape, each consisting of seven joints, including the
small basal joint by which it is attached to the body, and
the very minute terminal hook. The joints of the tail
are almost undeveloped, the whole tail being scarcely
larger than the preceding segment. In the intermediate
state the third and fourth pairs of legs are considerably
elongated, and the fifth pair have become cheliferous.*
The tail and its appendages have also acquired consi-

* The progress of development in this genus offers a curious contrast to
that of Brachyscelus crusculum as described by Spence Bate, ‘* Annals of
Natural History” for July, 1861, in which the sixth pair of legs are cheliferous
in the young stage, becoming simple in the adult.

26 PHRONIMIDA.

derable development, although still shorter and compara-
tively more robust than in the perfect animal. The eyes,
in the perfect state, have afforded very interesting details.
In addition to the lateral pair of the ordinary form,
connected with the lateral extremities of the brain, are a
superior pair of organs of sight, the nerves of which are
considerably elongated, arising from intermediate dila-
tations of the brain, and terminating in a mass of small
knobs. The basal portion of these nerve-filaments
forms a dark red mass, so that, in these respects, the
animal is quite analogous to Ampelisca Gaimardii, described
in our Vol. i. p. 128.

The only specimen of this species which we have seen
as a native of the British coast, is one in the British
Museum, taken by Dr. Fleming on the 3rd November,
1809, at Burray, in Zetland, amongst rejectamenta of the
sea. This specimen, unfortunately, is in a very dilapi-
dated condition. We have, therefore, found it necessary
to present our readers with a figure drawn from a speci-
men of unknown habitat, with which we have compared
the British type. Other specimens from the Shetland
Islands were obtained by the late Dr. Johnston, and
exhibited by him before the Berwickshire Naturalists’
Club in 1855 (Proceedings, ii. p. 212).

The animal is more abundant in warmer latitudes;
and the fact of its having been found so far north is to be
attributed, probably, to the currents of the Great Gulf
Stream. Risso describes the animal as being transparent,
shining, and covered with red spots. Desmarest says
that it is to be found mostly in the cavities of Pyro-
soma and Beroe. Several specimens of the Phronime
within the latter animals, open at both ends, are pre-
served in the Hopeian Collection at Oxford; the cavity
of the latter, in one instance, containing a large num-

PHRONIMA SEDENTARIA. Q

ber of young Phronime, in company with their parent.
In the British Museum is a specimen of Doliolum papil-
losum, of Delle Chiaje, from Naples, in which a specimen
was found, and which is represented in our figures at the
head of this description,* the small white dots repre-
senting small masses of calcareous matter. Mr. Mac-
Donald has informed us that he has kept some alive
while inhabiting specimens of Doliolum, and that it was
chiefly through the agency of the crustacean that the
medusa was propelled through the water, adding that as
they progressed they frequently rolled over and over.

* Figured also by Delle Chiaje, ‘‘ Animali Invertebrati, tay. xxiii. ; see
also Otto, in ‘‘ Nova Acta,” xi, p. 313.

28 ABERRANTIA.

Group—ABERRANTIA.

Tuts group is distinguished from the more typical
Amphipoda by the abnormal condition or the absence of
one or more segments of the pleon, as well as by the
coxe not being largely developed into scales, and being
mostly fused with their respective segments of the
pereion.

This group comprises the genus Dulichia together with
the LamopipDa4, an order founded by Latreille to sepa-
rate the genus Caprella from the Isopopa, amongst which
naturalists had previously arranged it.

It corresponds with the order Lamoptieopa of Milne
Edwards, including the family Dulichide of Dana.

Fam. I.—DULICHIID.

PEREION six-jointed ; the last two segments fused into
one. The last segment of the pleon absent. Telson squa-
miform. Fifth pair of pereiopoda attached to the pos-
tero-inferior angle of the sixth segment. Posterior pair
of pleopoda wanting.

In the typical forms of Aberrant Amphipoda, all the
legs have the coxee fused with the respective segments of
the body, and the tail is reduced to a rudimentary condi-
tion. In CerErcops the tail, though rudimentary in
appearance, has, according to Kréyer’s figure, but one
segment wanting. The absence of the natatory appen-
dages, as well as of the first two pairs of walking legs,

approximates this genus to Caprella. It is clear, there-

DULICHIID®. 29

fore, that the only persistent character distinguishing the
ABERRANTIA from the NorMALtIa is the absence of one or
more segments from the tail. We are justified, conse-
quently, in associating this family with the Aberrant
rather than with the Normal group of Amphipoda,
amongst which it has been previously arranged.

As yet, but a single genus is known belonging to this
family.

The Vignette below represents a sketch taken by Dr.
Walker of a jetty at New Brighton on the Mersey, off
the mouth of which he took some animals of this genus.

30 ABERRANTIA.,

AMPHIPODA. DULICHIIDA.

Genus—DULICHIA (Kréyer).

Dulichia. Kroyrr, Nat. Tidsk. n.s. i. p. 521. Voy. en Scand. pl. xxii.
fig. 1. Spence Bars, Ann. Nat. Hist. xx. p. 526.
Dyopedos. Spencrk Bartz, Ann. Nat. Hist. 2 ser. xix. p. 150.

Generic character. Superior antennz longer than the in-
ferior. Inferior antennz inserted posteriorly to the superior.
Gnathopoda chelate. Pereiopoda subequal, having neither the
coxre nor basa developed into scales. Three anterior pairs of
pleopoda normal; fourth and fifth terminating in two styliform
rami; sixth obsolete. Telson single, lanceolate.

In this genus the animals have the bodies long and
narrow; the eyes normal; the superior antennz longer
than the inferior, both pairs carrying short flagella. The
inferior pair arise farther back than the superior. The
hands of the first two pairs of legs are more or less
chelate. All the legs have the first joint small and squa-
miform, that of the last two pairs being fused with the
fifth segment of the body. Each of the caudal appen-
dages terminates in two styliform rami. The middle tail-
piece is single and pointed.

This genus appears to be essentially arctic. It was
from thence that Kroéyer obtained the type of the genus,
specimens of which we have scen attain the length of one
inch and a quarter. The species taken on the northern
shores of this island scarcely reach to the length of a
quarter of an inch, while those from the western shores
are still smaller.

DULICHIA PORRECTA. oll

AMPHIPODA. DULICHIID&.
ABERRANTIA.

DULICHIA PORRECTA.

Specific character. Cephalon not produced into a rostrum. Pereion and
pleon dorsally smooth. Eyes round, not elevated upon a tubercle. Superior
antenne about half the length of the animal; flagellum shorter than the last
joint of the peduncle. Second pair of gnathopoda having the propodos long
and armed with two straight and anteriorly-directed teeth, the posterior one
being the longer.

Length } inch.

Dulichia porrecta. Svrencz Bats, Cat. Amph. Brit. Mus. p. 348, pl. liv.
fig. 9. Ann. Nat. Hist. xx. p. 526. Wut, Pop.
Hist. Brit. Crust. p. 209.
Dyopedos porrecta, Spence Bate, Ann. Nat. Hist. 2 ser. xix. p. 151.
Tus species differs from D. spinosissima, on which
Kroyer founded the genus, in the following particulars :
—The head is not produced forwards into a sharp
rostrum; the body and tail are smooth, being free from
teeth or spines. The eyes are round, but not raised upon
a stout tubercle. The superior antennez are about half
the length of the extended animal. The first joint of
the peduncle is short and robust, but the two succeeding
are long and slender. The flagellum (probably) is about
half the length of the last joint of the peduncle.

a2 DULICHTID.E.

The inferior antennz are shorter than the superior,
reaching scarcely to the extremity of the peduncle of the
superior. The first pair of legs have the hand small,
short, and oval, the palm being oblique and imperfectly
defined. The second pair of legs are much larger than
the first, and have the hand long, but not very broad.
It is armed anteriorly and inferiorly with two long,
straight teeth, directed forwards, the posterior being the
longer. The finger is short, thick, and double-lobed
upon the inner margin. The coxz of the second pair of
legs are produced in front to a point. The caudal
appendages are sub-equal, and the middle tail-piece is
pointed.

We first received this specimen from Mr. Gregor, of
Macduff, who procured it from the Moray Frith, and
subsequently from Dr. Walker, who took it in deep
water between the rivers Dee and Mersey.

The specimens received from Dr. Walker differ from
the type of the species so much that we hesitated in con-
sidering them identical. After full consideration, how-
ever, we feel assured that the alteration of form is one of
variation, dependent upon some altered conditions in the
history of the animal.

The specimens from the mouth of the Dee have the
hand of the second pair of legs shorter, stouter, and more
oval than in the type, but the armature is the same, except
that the inferior tooth is not quite so far behind the
first, and not directed so straight forwards.

One of these specimens was a female, and, fortunately,
the larva were in a mature condition, which enabled us
to ascertain that the absorption of the seventh into the
sixth segment is a feature from the earliest existence of
the animal. The larva is distinguishable from the adult
by the shortness of the antenne, the small sizes of the
hands, and the shortness of the last pair of legs.

DULICHIA FALCATA. 33

AMPHIPODA., DULICHIIDA.
ABERRANTIA,

DULICHIA FALCATA.

Specific character, Cephalon without a rostrum. Body smooth. Superior
antennz about two-thirds the length of the animal. Second pair of gnatho-
poda having the propodos armed beneath with a crooked tooth near the base,
and a sharp curved tooth near the distal extremity.

Length, } inch.
> 74

Dulichia falcate. Srence Bate, Ann. Nat. Hist. xx. p. 526. Cat. Amph.
Brit. Mus. p. 348, pl. liv. fig. 10. Wuurre, Pop. Hist.
Brit. Crust. p. 209.

Dyopedos falcata. Srence Bare, Ann. Nat. Hist. 2 ser. xix. p. 151,

In general appearance this species closely resembles
the preceding. The head is not produced into a rostrum.
The body and tail are smooth, being free from teeth or
spines. The eyes are round, and rather large. The
superior antennee are long, quite two-thirds the length of
the animal. The first joint of the peduncle is shorter
than the head, but each of the two succeeding (which are
slender, and nearly of the same length) are three times as
long as the first. The flagellum is not so long as the last

VOL. Il. D

34 DULICHIID®.

joint of the peduncle. In our unique specimen, which is
also imperfect in other parts, the inferior antenne are
lost. The first pair of legs have the hand tapering to
the distal extremity. The palm is very oblique, and but
very imperfectly, if at all, defined. The second pair of
legs are very robust, and have the hand long, the palm
armed with two curved teeth, the distal tooth being
sharp and slightly curved, the basal (by which the limit
of the palm is defined) being crooked. The finger is
rather long, sharp, curved, and slightly waved upon the ~
inner margin, The third and fourth pairs of legs are
smaller than the three succeeding, which are very long,
and furnished with fine hairs upon the under surface of
the fifth joint.

We also received this species from Mr. Gregor, of
Macduff. It came to us mixed with D. porrecta and some
imperfect specimens which had no teeth on the hand.
These latter we believe to be females of this species.

It was taken in the Moray Frith.

CAPRELLIDA., 35

Fam. Il.—CAPRELLIDZ.

PEREION cylindrical. Pleon rudimentary. Appendages
attached to the cephalon normal and well-developed.
Pereiopoda having the first joints, or coxa, fused with
the segments of the pereion to which they are respectively
attached. Branchiz attached to the third and fourth
segments of the pereion. Pleopoda rudimentary or
obsolete.

It is to the species belonging to the several genera in
this aberrant family that the popular name of spectre or
skeleton shrimp has been applied, the idea being sug-
gested by their thin and skeleton appearance, as they
crawl among the weeds under water.

The slender elongated form of these animals well con-
trasts with the short and dilated bodies of those com-
posing the following family Cyamide., ‘These animals
also are free and roving in their habits, whilst the Cyami
are parasitic upon the Cetacea, and evidently, from their
structure, sluggish in their movements.

The Caprellidz have recently been divided by Kroyer
into several genera beyond those adopted in the following
pages, founded, for the most part, on the relative structure
of the minute terminal portion of the body, and the
greater or less development of its rudimental segments
and appendages. These characters appear, however, to
us of too slight importance to warrant such a step, the
more so since they only exist in an abnormal condition.

36 CAPRELLID &.

AMPHIPODA. CAPRELLID.
ABERRANTIA,

Genus— PROTO.

Proto. Leacu, Linn. Trans. xi. p. 362, 1814. Desmarest, Consid.
sur Crust. p. 276, 1825. Spence Barn, Cat. Amph. Brit.
Mus. p. 349.

Leptomera. LATREILLE, in Cuvier, Régne Animal, Ist ed. iii. p. 51, 1817.
DrsmAreEstT, Consid. sur Crust. p. 275. Gurrty, Icono-
graph, R. An. Crust. pl. xxviii. fig. 38. Kroyzr, Nat.
Tidsk. iv. p. 496. Mitnse Epwarps, Hist. des Crust. iii.
p. 109. GossE, Mar. Zool. i. p. 131.

Naupredia, Uarrurnue, in Cuvier, Régne Animal, 2nd ed. iv. p. 128.
Cours d@’Entomol. p. 393. Van Benepren, Faune litt. de
Belgique.

Generic character. Cephalon confluent with the first seg-
ment of the pereion. Pereion having the last joint shorter
than the preceding, cylindrical. Pleon rudimentary. Gnatho-
poda subchelate. Three anterior pairs of pereiopoda short and
feeble, last two long and powerful.

In this genus the head is small and globular, and so
closely attached to the first segment of the body that it
can only be distinguished from it by close observation.
The body is cylindrical, and the tail is rudimentary. The
eyes, antennze, and organs forming the mouth are similar
to those in the group Normatta, but the legs have the
first joint closely fused with the respective segments to
which they are attached. In this respect we perceive a
resemblance to the development of the same parts in the
highest organized decapods. Many genera of the Bra-
chyura have the coxe as closely anchylosed with the
pereion as we here see exhibited in animals at the oppo-
site extremity in the scale of development. The first
two pairs of legs are subchelate, the second being the
larger. The next four pairs are equidistant from each

PROTO. ou

other, while the seventh pair are much nearer the sixth.
The fifth pair of legs are the shortest, the fourth pair
being longer, and the third still a little longer. The last
two pairs of legs are long and powerful. The branchie
are attached to the second, third, and fourth pairs of
legs. The tail is rudimentary, and the appendages at-
tached to it almost obsolete.

The geographical range of this genus is, as yet,
limited to the British seas and the adjacent coast, with
the exception of a single specimen taken by Dana on the
south-eastern shores of South America.

Latreille appears to have made much confusion respect-
ing the nomenclature of the present group by attempting,
in his different works,* to distinguish his genus Leptomera
from that of Proto of Leach, proposing also a third
generic name Naupredia (Naupridia, Milne Edwards), for
an animal described as having only ten legs in a con-
tinuous series, those of the second, third, and fourth
pairs having a vesicle at the base, and which is evidently
a Proto with the sixth and seventh pairs of legs acci-
dentally broken off.}~ He has evidently, also, fallen into
error in giving the Gammarus pedatus of Montagu and
of Miller and the Squilla ventricosa of Miller as three
distinct species, referable to separate sections or sub-
genera.

* Régne Animal, Ist edit. iii, p. 51 ; 2nd edit. iv. pp. 127, 128. Nouv.
Dict. @Hist. Nat. 2nd edit. p. 4383 (Art. Chevrolle) ; xvii. p. 485 (Art.
Leptomere) ; xxviii. p. 177 (Art. Proton).

+ Van Beneden (Recherches sur la Faune litt. de Belgique, Crust. 1861,
p. 97, pl. xvii.) has described a species which he names Naupredia tristis,
asserting that it is a perfect animal, and not a mutilated Proto (Leptomera).
It is only five millemetres long, and is most probably in a very young state.
It entirely agrees with Proto, except in the inarticulated flagellum of the
antenne and want of the four hind legs. It is possible that these may
be subsequently developed ?

38 CAPRELLID®.

AMPHIPODA. CAPRELLIDE,
ABERRANTIA.

PROTO PEDATA.

Specific character. Superior antenne nearly half the length of the
animal. Inferior antenne about half the length of the superior. First pair
of gnathopoda having the propodos triangular, palm oblique, armed with
small spines, and defined by a sharp tooth. Second pair of gnathopoda
having the propodos long, ovate; palm waved, being oblique nearly two-
thirds the length of the joint, and defined by a process, armed with a strong
spine.

Length § inch.

Gammarus pedatus. ABILDGAARD in MuiiEr, Zool. Dan pt. iii.
p. 33, pl. ci. figs. 1, 2.

Cancer (Gammarus) pedatus. Montagu, Trans. Linn. Soc. xi. p. 6, pl. ii.
fig. 6.

Proto pedata. Fiemine in Edin. Phil. Journ. viii. p. 296.
LEAcu, in Edin. Encye. vii. p. 433. Trans.
Linn. Soc. xi. p. 362. Spence Bate, Rep.
Brit. Assoc. 1855. Ann. Nat. Hist. 2 ser.
xix. p. 151. Watts, Pop. Hist. Brit. Crust.
p- 218. Cat. Brit. Crust. p. 61. Jonnston,
Mag. Nat. Hist. viii. p. 673, figs. 72, 73.

PROTO PEDATA. 39

Proto pedatum. Desmarest, Consid. sur Crust. p. 276.
Leptomera pedata. Gossr, Mar. Zool. p. 181. fig. 224.
Leptomera pedata. LATREILLE, Régne An. iii. p. 51. Gurr,

Iconogr. Crust. pl. xxviii. fig. 3. MILNE
Epwarps, Hist. des Crust. t. iii. p. 109.
Kroyer, Nat. Tidsk., iv. p. 607, pl. vii.
figs. 13-23. Drsmarest, Consid. sur Crust.
p. 276, pl. xlvi. fig. 3.

Squilla ecaudata (Female). Gronovius, Act. Helv. p. 439, pl. iv. figs. 8,
9, 10.

Squilla ventricosa. MuueER, Zool. Dan. pt. ii. p. 20, pl. lvi. figs.
1,19 35%

Tue animal is long, linear, cylindrical, and smooth, the
head being intimately soldered with the first segment of
the body. The eyes are small and round. The superior
antenne are about half the length of the animal; the
flagellum being as long as the last two joints of the
peduncle. The inferior antennz are about half the
length of the superior, the flagellum being about half the
length of the peduncle. The first pair of legs are small,
having the hand acutely triangular, tapering to the finger.
The palm is as long as the posterior margin, and armed
with two or three rows of minute spines, its limit being
defined by a sharp process, carrying one or two spines.
The second pair of legs are at a considerable distance
from the first, and situated near the middle of the second
segment of the body. They are as long again as the
first, and the hand is about twice as long and broad as
that of the preceding pair. It is of a narrow oval form,
having the palm more than half the length of the hand,
defined by a sharp process, furnished with a small, stout
spine; it is excavated near the posterior limit, is wavy
throughout its length, and armed with small processes
tipped with spinules.* The third pair of legs are feeble

* Dr. Johnston describes two varieties of this species—the first having the

hands oval, with a single denticle at the base, the head rounded in front,
and the branchial lamelle large and elliptical (to which the figures of Miller

4.0 CAPRELLIDE.

in appearance, and have the posterior margin of the
penultimate joint armed with four radiating spines. The
fourth pair are like the third, but smaller, while the fifth
are so much smaller and imperfect in their condition
as to partake of a rudimentary character. They are,
moreover, directed backward; that is, contrary to the two
posterior pairs, and therefore contrary to its normal con-
dition. The two posterior pairs of legs are attached
near together, in consequence of both being situated at
the posterior extremity of their respective segments,
the last of which is much shorter than any of the others.

This single feature is sufficient to enable the observer
to detect an animal of this genus, however otherwise
damaged, since in Caprella, &c., the last two joints are
always short, and hence the last three pairs of legs are
always in close juxtaposition. The last two pairs of legs
are longer than the others, and have the penultimate
joint, for nearly two-thirds of its length, armed with two
spines, opposed to the extremity of the finger which
closes upon the preceding joint. The tail is rudimentary,
consisting, when recent, of a cylindrical tube, without
any limbs except two pairs of rudimentary, styliform
appendages, situated near the extremity of the preceding
segment, which probably fulfil the same office as their
homologues in the male brachyurous crustacea.

We anticipate that the geographical distribution of
this species will be ultimately found to be more general
than our experience has yet ascertained. I[t was first
taken as British by Montagu on the southern coast of

and Montagu belong) ; and the second with the first pair of hands trianeu-
lar, somewhat lobed at the base, the wrist deeply serrated, the second pair
of hands oval with two teeth at the base, and serrulate along the palm, head
very obtuse in front, and the branchial lamelle smaller and cylindrical (to
which all the Berwick specimens are referable).

PROTO PEDATA. 41

Devonshire, where we have likewise found it. The Rev.
Mr. Gordon has sent it to us from the Moray Frith; so
also have Mr. Gregor and Mr. Edward. The Rev. A.
M. Norman has taken it in about forty fathoms one mile
north of Whalsy lighthouse, in the Shetlands, and Milne
Edwards records it from Denmark, where, in fact, the
species was first discovered. Dr. Fleming found it at the
Bell Rock, and Dr. Johnston in Berwick Bay, and
Mr. R. Q. Couch at Mousehole Island, Cornwall.

42 CAPRELLID&.

AMPHIPODA, CAPRELLID A.
ABERRANTIA.

PROTO GOODSIRII.
Goodsir’s Spectre Shrimp.

Specific character. Superior antennx about one-third the length of the
animal, Inferior antenne about one-half the length of the superior.
Second pair of gnathopoda having the propodos large, arcuate above, palm
excavated, and armed beneath, near the base and distal extremity, with a
small tooth.

Length 3 inch.

Proto Goodsirii. Srence Bats, Ann. Nat. Hist. 2 serv. xix. p. 151. Cat.
Amph. Brit. Mus. p. 350, pl. lv. fig. 2. Wurre, Pop.
Hist. Brit. Crust. p. 218.

Tus species is a larger and more powerful-looking
animal than P. pedata, from which it differs chiefly in the
form of the second pair of hands.

The superior antennz are about one-third the length
of the animal, and the flagellum is about as long as the
peduncle. The inferior antennz are about half the length
of the superior—that is, scarcely reaching to the extremity
of the peduncle of the latter. The first pair of legs have
the hands elongate-ovate, broadest at the base, and nar-
rowed at the extremity; palm very oblique, slightly con-
vex, minutely serrated, defined near the posterior extre-
mity by an obtuse tooth. The second pair of legs have
the hands very large, rounded above, and having the palin

PROTO GOODSIRII. 43

concave, and frequently furnished with one or two sub-
membranous hollow sacs. This latter feature (if our
experience has not deceived us) is present only after
death.. We have observed this structure only in this
family, and Dana has likewise figured it. The palm is
armed near the base and distal extremity with two small
teeth; the finger is much curved, and its extremity
alone impinges against the palm. The third pair of legs
are rather longer than the second, and have the hand
serrated and furnished with a few cilia. The fourth pair
are like the third, but shorter; the fifth are still shorter.
The sixth and seventh are long and powerful, having the
wrists, as well as the hands, furnished with uneven teeth
and a few hairs. The tail is very rudimentary, and sup-
ports in the male a single pair of rudimentary propoda.
The branchiz are attached to the second, third, and
fourth pairs of legs.

This species has been named in honour of the lamented
Mr. Goodsir, who promised fairly to distinguish himself
in this branch of Natural History. It appears to be a
northern species, since we have received it only from the
Moray Frith, through the kindness of the Rev. George
Gordon, from the Shetlands, where it was dredged by the
Rev. A. M. Norman, and who also has found it on the
coast of Durham.

Ad. CAPRELLID.E.

AMPHIPODA. CAPRELLID A.
ABERRANTIA.

Genus—PROTELLA.

Protella. Dana, U. 8. Explor. Exped. p. 812. Spuncr Bars, Cat. Amph.
Brit. Mus. p. 351.

Generic character. Cephalon confluent with the first seg-
ment of the pereion. Pereion having the last two segments
shorter than the preceding. Pleon rudimentary. Appendages
to the cephalon well developed. Gnathopoda subchelate ; first
two pairs of pereiopoda rudimentary, but having branchice
attached ; last three pair subequally long and robust. Anterior
pair of pleopoda rudimentary, the rest obsolete.

Tuis genus differs from Proto in several important
points: among the most conspicuous is the very rudi-
mentary character of the third and fourth pairs of legs,
which are represented by two small, uni-articulate, leaf-
like plates. The penultimate segment of the body is as
short as the last; consequently, the last three pairs of
legs are situated closely together at the posterior ex-
tremity of the animal. Branchiz are attached to the
third and fourth segments of the body, which, in the
female, have also attached the plates belonging to the
incubatory pouch.

This genus was established by Dana, as possessing a
character intermediate between that of Proto and Ca-
prella, from which last it is distinguished by the character
of the appendages of the intermediate segments of the
body.

Our knowledge of this genus is, as yet, confined to
two species, one belonging to Britain, the other to South
America; therefore its geographical range cannot pro
perly be estimated.

PROTELLA PHASMA. 45

AMPHIPODA., CAPRELLID &.
ABERRANTIA.

PROTELLA PHASMA.
Montayw’s Skeleton Shrimp.

Specific character. Cephalon, without a rostrum, dorsally armed with a
strong spine, originating in the posterior margin and directed upwards and
forwards. First segment of the pereion dorsally and posteriorly armed with
a strong tooth ; second segment similarly armed with a pair near the middle,
and one near the posterior margin.

Length rather more than half an inch.

Cancer phasma. Monraau, Trans. Linn. Soe. vii. p. 66, pl. vi.
fig. 3.

Caprella phasma. Lamarck, Syst. des An. sans Vert. v. p. 174.

Caprella phasma. LATREILLE, Encyc. Met. p. 336, fig. 37.

Leacu, Edin. Encye. vii. p. 404. Ene. Brit.
Suppl. 1, p. 426. Samovettze, Ent. Comp.
p. 105. Dersmarest, Consid. sur Crust.
p. 278. Minne Epwarps, Hist. des Crust.
iii. p. 108. Wuuirr, Cat. Crust. Brit. Mus.
1847. Cat. Brit. Mus. 1850, p. 60. Pop.
Hist. Brit. Crust. p. 216. Fiemie in Edin.
Phil. Journ. viii. p. 297. Jounston in Lou-
don’s Mag. Nat. Hist. viii. p. 669. RatHKE,
Nov. Act. xx. p. 95. GossE, Mar. Zool. p. 223.
R. Q. Coucu, Rep. Penzance, N. H. Soe.
1852, p. 96.

gina longispina. Kroyer, Nat. Tidsk. 2 ser. i. p. 476, 1844-6.

Protella longispina, Spence Batre, Ann. Nat. Hist. 2 ser. xix.
pe Loi:

46 CAPRELLIDE.

Caprella spinosa. Goopstr, Edin. Phil. Journ. xxxiii. pl. 3,
f. 1-3. Wnutrr, Pop. Hist. Brit. Crus. p. 197.

Protella phasma. Sprnce Barts, Cat. Amph. Brit. Mus. p. 351,
pl. lv. fig. 4.

A stacus phasma. Pennant, Brit. Zool. iv. p. 27, Edit. 1812

(descr. only).

Tue head of this species is rounded in front, while a
sharp, strong tooth, directed forwards as well as upwards,
is situated upon the dorsal surface of the posterior mar-
gin just where the head is contiguous with the first joint
of the body, from which it can scarcely be identified.
The first joint of the body is likewise furnished with a
similarly strong, sharp-pointed tooth, situated near its
posterior margin. The second segment carries near the
centre a pair of strong teeth, one on each side of the
dorsal median line, as well as a third, situated in the
middle of the dorsal surface, near the posterior margin.
The third and fourth segments exhibit rudimentary pro-
cesses, probably representing teeth in similar positions.
The superior antenne are rather more than half the
length of the animal. The inferior antennz are about
half the length of the superior, The first pair of legs
are short; the hand triangular; the palm defined by a
sharp process. ‘The second pair are very much longer ;
the hand is large, elongate-ovate, the palm having a deep
excavation near the anterior extremity, and defined by a
prominent blunt tooth, surmounted by one or more
spines. The finger articulates with the hand somewhat
before the apex, so that a sharp process is produced
above and beyond the articulation, The three posterior
pairs of legs have the hands arcuate, the anterior margin
being armed with small tubercles, surmounted by a spine,
and defined by a strong process, which is surmounted by
several short spines directed towards the extremity, and

PROTELLA PHASMA. 47

corresponding with the extremity of the finger when
closed.

The female appears to differ in no essential character
from the male, except in the possession of the ovigerous
sac, the plates of which are attached to the third and
fourth segments of the body.

Col. Montagu, who was the discoverer of this species,
was also the first to observe the love that exists between
the parent and the offspring in this group of Crustacea.
He writes, in the seventh volume of the Transactions of
the Linnean Society :—‘‘ While examining a female in a
watch-glass of sea-water under a microscope, we were
agreeably surprised to observe not less than ten young
ones crawl from the abdominal pouch of the parent, all
perfectly formed, and moving with considerable agility
on the body of the mother, holding fast by their hind
claws, and erecting their heads and arms.”

This species is generally of a straw colour, delicately
spotted with pink, fine specimens having the fingers
banded with pink. As in all cornuted species, the spines
on the head and the armature of the hands vary greatly.
The animal represented by Goodsir under the name of
C. spinosa has the occipital and dorsal horns of large size,
as well as those upon the second pair of hands.

This species appears to be more abundant in the
southern parts of Great Britain than in the northern,
although we have it recorded from one extremity to the
other. It was first found in Devonshire by Col. Mon-
tagu, and we have frequently obtained it in the neigh-
bourhood of Plymouth. Mr. Gregor has sent it to us
from the Moray Frith. Dr. Fleming obtained it from
the Isle of Man, while Mr. Goodsir records it from
the Frith of Forth. The Rev. A. M. Norman has
taken it at Cullercoats, Northumberland, and Mr. R. Q.

48 CAPRELLIDA.

Couch among conferve, at Lariggan Rocks, Mount’s
Bay, Cornwall. In Norway it has been recorded by
Rathke, and Kréyer has procured it at Christiana in
Sweden.

The following vignette represents one of these spectre-
shrimps prowling through the deep recesses of a submarine
graveyard, such as Clarence dreamt of when he said :—

‘¢ Methought I saw a thousand fearful wrecks,
A thousand men that fishes gnawed upon,
Wedges of gold, great anchors, heaps of pearl,
Inestimable stones, unvalued jewels,
All scattered at the bottom of the sea.
Some lay in dead men’s skulls; and in those holes
Where eyes did once inhabit, there were crept
(As ’twere in scorn of eyes) reflecting gems,
That woo'd the slimy bottom of the deep,
And mocked the dead bones that lay scattered hy.”

CAPRELLA. 49

AMPHIPODA. CAPRELLIDA,
ABERRANTTIA.

Genus—CAPRELLA.

Caprella Lamarck, Hist. des Anim. sans Vert. p. 165. Lracu, Linn.
Trans. xi. p. 363. Mitye Epwarps, Hist. des Crust. iii.
p. 105. Kroyer, Nat. Tidssk. iv. p. 496.

gina. Kroyer, Nat. Trpssk. iv. p. 509.

Podalirius. Kroyer, Nat. Tidssk. 2 Ser. i. p. 283.

Generic character. Cephalon confluent with the first seg-
ment of the pereion. Pereion cylindrical, with the last two
segments shorter than the two preceding; in the male the
first two segments are long, in the female they are shorter.
Pleon rudimentary. Appendages of the cephalon normal.
Gnathopoda subchelate; in the male the second pair of
gnathopoda articulates with the pereion near the middle or
posterior extremity of the second segment, in the female at
the anterior extremity of the same segment. First two pairs
of pereiopoda wanting. ‘Three posterior pairs subequal, and
placed near to each other. One or two pairs of pleopoda rudi-
mentary, the rest obsolete.

Tue head is confluent with the body. In the male the
first segment of the body is longer than in the female,
and the first pair of legs are always attached at the ante-
rior extremity. The second segment is longer in the male
than in the female, and we are strongly inclined to be-
lieve that it increases in length with the age of the
animal. The second pair of legs always articulate, in
the female, at the anterior extremity of this segment ;
whereas in the male they are affixed farther back, and
generally posteriorly to the centre of the segment, and

VOU. I. E

50 CAPRELLID ®.

sometimes quite at its extreme posterior limit. The
three succeeding segments are generally of equal length,
while the last two are always very short.

Mr. Goodsir, who paid considerable attention to this
family, says, in the ‘ Edinburgh Philosophical Journal ”
for 1842 (vol. xxili. p. 186) :—** The Caprelle, like all
the lower Crustacea, cast their skins often. Before the
process commences, the animal lies for a considerable time
languid, and to all appearance dead. At length a slight
quivering takes place all over the body, attended in a
short time with more violent exertions. The skin then
bursts behind the head in a transverse direction ; and also
down the mesial line of the abdominal surface. A few
more violent exertions then free the body of the old
covering. After this the animal remains for a consi-
derable time in a languid state, and is quite transparent
and colourless.”

The habits of these animals have not been much ob-
served, living, as they do, amidst sea-weeds and zoophytes,.
They are active in scrambling from branch to branch, and
are very likely to be overlooked. Mr. Goodsir, indeed,
says that they are never seen to catch their prey, and
‘being slow and deliberate in their motions, they are not
fitted for this mode of life;” to which we cannot sub-
scribe, inasmuch as our experience would induce us to
pronounce them to be active and energetic creatures.
They generally grasp the objects to which they are
attached by their strong posterior legs, and elevating
themselves in an erect position, wave about their long
antenne, probably in search of food. ‘Their usual
mode of progression” is compared by Otho Fabricius
(Faun. Grénl.), Montagu, Goodsir, and Gosse, “to that
of the larve of the Geometric moths.” ‘ They some-
times,” says Mr. Goodsir, “ walk in this way for a consi-

CAPRELLA. 51

derable time, and then suddenly stop, remaining perfectly
motionless, not even moving their antenne.”

They seldom attempt to swim, and will, when placed
in the water independently of anything to rest upon,
generally drop listlessly to the bottom. Mr. Gosse says,
in his pleasant Naturalist’s Rambles on the Devonshire
Coast, “ I have seen a large red species swim, throwing its
body into a curve like the letter S, with the head bent
down and the limbs turned back, the body being in an
upright position. It was a most awkward attempt; and
though there was much effort, there was little effect.”

Kroyer has separated from this genus two others
upon characters which appear to us to be very doubtful.
The tail in Caprella is rudimentary, and exists in a semi-
membranous condition. The development of this abnor-
mally rudimentary part is, within small limits, variable.
Upon the degree of its development Kroyer has founded
the genera Podalirius and Afgina. It is only after a care-
ful consideration of the structure of the animals that we
have arrived at the conclusion that the establishment of
these two genera 1s unnecessary. The genus Cercops also
of Kroyer is mainly distinguished from Caprella by the
small terminal abdomen being six-jointed and styliferous,
but the second pair of legs have a vesicle at the base, as
in Proto.

The geographical distribution of this genus is very
universal, since species are recorded from almost every
locality that has been visited by the carcinologist.

52 CAPRELLID.E,

AMPHIPODA., CAPRELLID&.
ABERRANTIA.

CAPRELLA LINEARIS.

Pennant’s Skeleton Shrimp.

Specific character. Cephalon and pereion smooth and unarmed. Second
pair of gnathopoda in the male having the propodos with the palm armed
with a single tooth, in the female with two small tubercles, and in both defined
by a short process armed with a spine.

Length 3 inch,

Cancer linearis. Linnazvs, Syst. Nat. ii. p. 10562 Herbst.
Krabben, ii. pl. xxxvi. fig. 9, 10.
Caprella lincaris. Mitnr Epwarps, Hist. des Crust. iii. p. 106.

DrsmarEst, Consid. sur Crust. p. 278. La-
TREILLE, Hist. n. Crust. et Ins. vi. p. 324,
pl. lvii. fig. 2-5. Jonunstox, Mag. Nat. Hist.
viii. p. 672, fig. 71. Risso, Crust de Nice,
p. 130. Goopnstr, Edin. New Phil. Journ.
xxxlli. p. 190, pl. iii. fig. 8. R. Q. Coucu,
in Rep. Penzance, Nat. Hist. Soc. 1852, p. 98.
Spence Bate, Ann. Nat. Hist. 2 ser. xix. p.
151. Cat. Amph. Brit. Mus. p. 353, pl. ly.
fig. 7. Wuutz, Cat. Brit. Crust. p. 59. Pop.
Hist. Brit. Crust. p. 214.

CAPRELLA LINEARIS. 53

Cancer (Astacus) atomos? PENNANT, Brit. Zool. ed. 1777, iv. p. 17, pl. xi.
fig. 832. Baster, Opuse. Subs. pl. iv. fig. 2.

Cancer (Astacus) punctata. Risso, Crust. de Nice, p. 130. Hist. Nat.
Eur. merid, v. 102.

Oniscus scolopendroides. Pauuas, Spic. Zool. ix. p. 78, pl. iv. fig. 15.

Squilla quadrilobata ? Miutrr, Zool. Dan. ii. pl. xxxvi. fig. 4-6, male ;
iii. pl. exiy. fig. 11, 12, female.

TuIs species must be considered as the type of the
genus. It has the head and back unarmed. In the male
the first segment of the body is longer than in the
female, as is also the second segment ; the three succeed-
ing are subequal in length, and a little shorter than the
second ; the last two are but half the length of the pre-
ceding. ‘The superior antennz are about half the length
of the animal, the peduncle being rather longer than the
flagellum. The inferior antenne are about half the
length of the superior, reaching scarcely to the ex-
tremity of its peduncle. The first pair of legs are short,
and articulate with the first segment of the body at the
anterior extremity: the hand is ovate, the palm very
oblique, straight, ciliated, and defined by a process or
tooth: the finger is serrated, and slightly curved. The
second pair of legs are a little longer than the first, and
articulate with the second segment just at the centre,
but in the female a little more anteriorly ; the hand is
long-ovate, having the palm defined by a process or
tooth, tipped with a spine, and armed with a tooth
situated anteriorly to the centre, and just before which is
a square-angled tooth or process. The last three pairs of
legs are short, robust, and have the hand excavated in
front, and armed with two small spines, which antago-
nize with the extremity of the finger when closed.

The incubatory pouch is an appendage which is de-
veloped when required for the purpose of carrying the
ova, as shown in the two figures given below. It con-

54: CAPRELLID®.

sists of four plates, two attached to the third, and two
to the fourth, segment of the body, arising upon the
under surface and the inside of the branchia. We have
observed this organ in various stages of development,
from the small pedicle to the shell-like scale.

The habits of this animal are curious, and repay the
naturalist for some patient observation. We have already
noticed the parental affection existing between animals in
this order and their offspring. In more than one species
of this genus similar observations have been made. As
soon as the young are old enough to enjoy a separate
state of existence they quit the protection of the ovi-
gerous pouch in which they have been nurtured, and,
passing out, climb, gipsy-like, to the back of their
mother, where they may be seen holding on in every con-
ceivable attitude. Mr. Goodsir, in writing of this
display of maternal care, says:—‘‘On one occasion,
while examining a female Caprella under the microscope,
I found that her body was thickly covered with young
ones. They were firmly attached to her by means of
their posterior feet, and they were resting in an erect
posture, waving about their long antenne with great
activity,” as represented in the vignette given in a subse-
quent page.

In the national collection is preserved a specimen of an
exotic species in which death has not separated the
parent from the offspring. They may still be seen
attached, as if climbing from the incubatory pouch to
the back of the parent.

They live mostly amongst weeds and submarine
growths, and “ are as much at home in the tree-like
zoophyte as a family of monkeys in their arborial bowers ;
and, indeed, their agility, as they run from branch to
branch, catching hold of a twig just within reach and

CAPRELLA LINEARIS. 55

pulling themselves in an instant up to it, then stretching
out their long arms in every direction, strongly reminds
one of the spider-monkeys of South America.” *

In 1854 Mr. P. H. Gosse sent us some minute speci-
mens of Caprelle which he had found in considerable
numbers on the rays of a small specimen of Solaster pap-
posa, which we have always considered as the young of
Caprella linearis, with which they agree in their general
character; but the second segment of the pereion is not
longer than the first and the superior antennz are
scarcely longer than the inferior; it is a remarkable
fact that some of the specimens, being females, are fur-
nished with the incubatory pouch. As these animals (of
which we give figures as a vignette on the next page) are
only one-tenth of an inch in length, we must either con-
clude that they are imperfectly-developed specimens of
C. linearis, and that they are endowed with the capability
of reproduction before they have attained to their adult
form and dimensions; or that they are a species distinct
in themselves, exhibiting the character of an imperfectly-
developed specimen of C. linearis.

Moreover, it is singular that they should have been
found in great abundance in this solitary instance, for we
are not aware of any having been similarly taken in any
other instance.

If they be young animals we must assume them to
have been of a single brood; but if so, it is a curious
feature in their history that the brood should remain
associated until the females were old enough to carry ova,
and that this latter circumstance should occur while the
animals were still so small.

Since the above has been written, Mr. Norman has

* Gosse’s Rambles of a Naturalist in Devonshire.

56 CAPRELLID&.

sent us several specimens that resemble the male of this
small variety. These vary in size, and we should not
hesitate to pronounce them to be the young of C. linearis ;
amongst them there is not a single specimen furnished
with the incubatory pouch, although some are larger
than those taken by Mr. Gosse.

CAPRELLA LOBATA. 57

AMPHIPODA, CAPRELLIDE.
ABERRANTIA.

CAPRELLA LOBATA.

Specific character. Body unarmed except by a few minute tubercles
occasionally present, especially upon the dorsal surface of the three posterior
segments of the pereion. First segment of the pereion long; second scarcely
longer than the first. Second pair of gnathopoda having the propodos long-
ovate; palm defined by one, and armed with two teeth, the anterior being
less distinct than the posterior.

Length ? inch.

Squilla lobata. MiituER, Zool. Dan. Prod. 197, No. 2859. O. Famr.
Fauna Grénl. p. 248. Samovretir, Ent. Comp.
p. 106.

Caprella lobata. GuERIN, Iconogr. R. An. Crust. pl. xxviii. fig. 2.

Kroyer, Voyage en Scand. pl. xxv. fig. 3a. Srmpson,
Nat. Hist. Invert. Grand Manan, p. 44. Tompson,
Ann, Nat. Hist. xx. p. 244. Spence Bats, Cat.
Amph. Crust. Brit. Mus. p. 354, pl. lv. fig. 8. Ann.
Nat. Hist. 2 ser. xix. p. 151.

Squilla quadrilobata. Mier, Zool. Dan. t. 114, fig. 11, 12.

Aigina longicornis. KroyEerR, Voy. en Scand. pl. xxvi. fig. 3.

Caprella levis. Goopstr, Edin. New Phil. Journ. xxxiii. p. 189, pl. iii.
fig. 4. Wuitr, Pop. Hist. Brit. Crust. p. 215.
Hist. Brit. Crust. p. 60.

Caprella linearis. Leacu, Edin. Ene. vii. p. 404 ?

In this species the animal is generally smooth, but
we have occasionally seen specimens which have a few
minute tubercles on the back, those most important and

58 CAPRELLID®.

constant being on the last three segments of the body,
and such are figured by Kroyer. The head is rounded in
front, and occasionally surmounted by a minute tubercle.
The first segment of the body, which is confluent with
the head, is rather long. The second is rather longer,
while the three succeeding are somewhat shorter, and
subequal in length. The superior antenne are not half
the length of the animal. The inferior scarcely reach
beyond the distal extremity of the second joint of the
peduncle of the upper. The first pair of legs articulate
with the body at the anterior extremity of the first seg-
ment of the body. The second pair of legs articulate
with the body behind the middle of the second segment:
the hand is long and oval, the palm being distinctly
defined by a strong tooth, and armed also near the
middle with two others, the anterior of which is fre-
quently less distinctly apparent than the posterior. All
the remaining parts bear a very near resemblance to those
of C. linearis.

Dr. Leach describes this species (under the name of
C. linearis) as being, when alive, of a brown colour, in-
clining to cinereous, beautifully spotted with rust colour.

All the specimens that we have examined of this
species are certainly males, and we have a strong convic-
tion that they are but fully-developed males of C. linearis,
from the fact that the specimens which we have described
as males of Caprella linearis only differ from those of C.
lobata in having the first and second segments of the body
shorter, these two segments being subject to vary in
length, and probably increasing with age. Furthermore,
we have never been able to determine the female of
C. lobata.

C. lobata is, moreover, generally associated with C.
linearis, and will probably be found to exist all round the

CAPRELLA LOBATA. 59

coasts of Europe. In Great Britain it has been obtained
at Kames Bay, N. B., by Mr. Robertson; in the Moray
Frith by Mr. Edward; at Cullercoats it was taken by the
Rev. A. M. Norman, and we have taken it at Ply-
mouth,

Specimens from the Frith of Forth are preserved in
the British Museum collection.

The accompanying vignette represents a female Caprella
carrying her offspring upon her back, as described at
page 54.

60 CAPRELLIDA,

AMPHIPODA. . CAPRELLIDA,
ABERRANTIA.

CAPRELLA ACUTIFRONS.

Specific character. Cephalon in both sexes anteriorly surmounted by a
strong tooth directed forwards. Second pair of gnathopoda having the pro-
podos with the palm deeply waved, and defined by an obtuse angle armed
with a spine ; limbs very robust.

Length J inch,

Cuprella acutifrons. LATREILLE in N. Dict. d’Hist. Nat. 2nd Edit.
vi. p. 433 (1816), Dusmarzest, Consid. sur
Crust. p. 277. Mintne Epwarps, Hist. des
Crust. iii. p. 108. Wurrr, Pop. Hist. Brit.
Crust. p. 216. Cat. Brit. Crust. p. 60.
Spence Bare, Cat. Amph. Crust. Brit. Mus.
p. 356, pl. Ivi. fig. 6. Van Breneprn, Re-
cherches sur la Faune littorale de Belgique,
p. 145, pl. xvi.>i fig. 9-11.

Cancer (Astacus) atomos ? Prynant, Brit. Zool. iv. pl. xiii. fig. 18, 2nd
ed. 1812 (very bad). Stew. Elements, ii.

p. 317.
Cuprella Penantis. Leacu, Edin. Encye. vii. p. 404. Sprncre Bate,
Ann. Nat. Hist. 2 ser. xix. p. 151.
Caprella Pennantti. Jounston in Ann. Nat. Hist. viii. p. 670.

R. Q. Coucn in Report Penzance, Nat. Hist.
Soe. 1852, p. 97.

In this species the male and female do not appear to
differ very materially. The head is surmounted by an
anteriorly-directed horizontal tooth, but the rest of the
body is smooth. In the male the first segment of the
body is scarcely longer than in the female, and the second
segment is not much longer than in the female, nor is it
longer than the third or fourth segments. The third and

CAPRELLA ACUTIFRONS. 61

fourth, which in the female carry the ovigerous plates,
have, in the male, the lateral walls (coxze) produced into
lateral plates, which are produced anteriorly to a point.
The superior pair of antennz are about two-thirds the
length of the animal, the flagellum is shorter than the
peduncle, and each articulus is infero-distally produced,
and furnished with cilia. The inferior antennz are
about the length of the peduncle of the superior, termi-
nating in a short flagellum, which consists of a long and
a short articulus. The first pair of legs are short, but the
form of the hand resembles that of the second. The
second pair of legs are longer than the first. In the
female they articulate with the extreme anterior limits of
the second segment, but in the male they articulate a
little posteriorly. The hand, in the male, is ovate,
tapering to the distal extremity; the palm is waved, and
defined by a strong tooth, armed with a stiff spine. In
the female the palm is less distinctly waved and de-
fined. ‘The three posterior pairs of legs are short and
robust.

The only animal that we have seen alive was covered
with numerous points or fine hairs. It was of a reddish
colour, shaded off into green.

This species appears to be one of the least dispersed in
the British seas, and our observations have consequently
been the more restricted.

It was found by Dr. Leach on the Devonshire coast,
and it has since been taken in Plymouth Sound by
Mr. Boswarva. ‘‘ Not uncommon among Corallines in
Mount’s Bay.”—Mr. R. Q. Couch.

Van Beneden states, that it is found in great abundance
on the shores of Belgium, in the middle of tufts of con-

fervee along with Tunais, upon the carapace of Chelonia
mydas.

62 CAPRELLIDA.

This species appears to have a near representative in
different parts of the globe. It differs but little from
C. geometrica of the United States, and is distinguishable
in the thickness of the body only from C. robusta from
Rio Janeiro. It closely resembles C. nodosa from the
Mauritius, and also a species recently sent to us by Mr.
Taylor, that we take to be identical with C. geometrica,
and which he procured in great abundance from amongst
the weeds at the bottom of an old yacht which had been
lying undisturbed for about two years in the harbour of
Hong Kong.

The vignette below represents a Gower Cockle Girl.

CAPRELLA HYSTRIX. 63

AMPHIPODA. CAPRELLID.
ABERRANTI4.,

CAPRELLA HYSTRIX.

Specific character. Tuberculated along the dorsal surface, the tubercles
increasing posteriorly. Second pair of gnathopoda having the propodos ovate ;
palm convex, defined by a blunt process surmounted by a spine.

Length 2 inch.

Caprella Hystrix. Kroyer Nat. Hist. Tidssk. iv. 603. pl. viii. fig.
20-26. Voy. en Scand. pl. xxiv. fig. 1 ?

Caprella acuminifera. Minne Epwarps, Hist. des Crust. t. iii. p. 107,
pl. xxxiii. fig. 21. Spence Bare, Cat. Amph.
Brit. Mus. p. 359, pl. Ivi. fig. 11 (mot of
LATREILLE and DESMAREST).

Tuis species is tuberculated throughout the entire
length of the animal, the tubercles increasing in size
towards the posterior extremity of the body. The head
is slightly angulated on the crown. The first segment
of the body is short; the second is longer, and of
the same length as the third, fourth, and fifth. The
sixth and seventh are shorter. The superior antennz are
less than half the length of the animal; the inferior are
not longer than the peduncle of the superior. The first
pair of legs are small; the second articulate near the
centre of the second segment of the body, but in the

64: CAPRELLID®.

female (figured above) they articulate quite at the ante-
rior extremity. This is the only reliable distinction that
we have been able to discover between the two sexes.
The hand in this pair of legs is ovate, the palm convex,
being defined by a process surmounted by a spine. The
palm is emarginate near the posterior extremity, and
waved a little anteriorly.

We consider this species to be identical with that
figured by M. Milne Edwards in the place cited, as also,
probably, with the C. Hystriz of Kréyer, although the
description of the head given by the former author,
** ovalaire, courte et arrondie en dessus,’’ seems to have
been derived from C. acanthifera, and his observation that
the penultimate joint of the last three pairs of legs is
narrow and without a tooth on the inner edge, disagrees
with our species (although agreeing with Kroyer’s details

‘of the legs of C. hystrix). Unfortunately M. Milne
Edwards is unable to clear up this difficulty, the speci-
men from which he drew his figure not having been
preserved.

Considering the C.acuminifera of Latreille to be identical
with C. acanthifera of Leach, we have been obliged to
take up Kiéyer’s name for the present animal, although
not quite agreeing with his description as above noticed.

We have received specimens of this species from
Millport, sent to us by Mr. Robertson ; from Northum-
berland, where it was found by the Rev. A. M. Norman,
and we have taken it in the neighbourhood of Ply-
mouth.

wa

CAPRELLA ACANTHIFERA. 65

AMPHIPODA. CAPRELLIDZ.
ABERRANTIA.

CAPRELLA ACANTHIFERA.

(Skull-headed Skeleton Shrimp.)

Specific character. Cephalon posteriorly and dorsally vaulted. First seg-
ment of the pereion short; second, third, and fourth subequally long, sur-
mounted by three large dorsal tubercles; fifth, sixth, and seventh segments
short, each surmounted by two sublateral parallel tubercles. Second pair of
gnathopoda having the propodos large in the male, rounded above and very
concave below, the palm defined by a prominent tooth ; in the female the
palm is slightly convex and the dorsal tubercles are less prominent.

Length §, of an inch in the male, and J, in the female.

Puce de mer arpenteuse. Du Qurronic, Mém. Math. et Physiq. Acad. Sci.
Paris, t. ix. p. 329, fig. a B.

Caprella acanthifera. Leacu, Edin. Ency. vii. p. 404 (not of Johnston
and Couch). W. THompson, Ann. Nat. Hist.
xx. p. 245. Wuuits, Cat. Brit. Crust. p. 60.
Pop. Hist. Brit. Crust. p. 215,

Caprelia calva. Spence Barr, Cat. Amph. Crust. Brit. Mus. p.
359, pl. lvi. fig. 11.

VOL. II. B

66 CAPRELLID®.

Caprella acuminifera, Larreriix, in Nouv. Dict. d’Hist. Nat. 2nd Edit.
vi. p. 438. Dusmarust, Consid. Crust. p. 277
(not of Johnston). Spence Barz, Ann. Nat.
Hist. 2 ser. xix. p. 151.

Tuts species may readily be detected from any other
by the peculiarly vaulted or skull-like head, together
with the tuberculated character of the body. The first
segment of the body is short. The three next are longer
than the first, equal to each other, and surmounted by
three dorsal blunt teeth, or tubercles. The two anterior,
immediately over the articulation of the second pair of
legs, are sublateral and parallel. The third is central, and
situated upon the posterior margin. The last three seg-
ments are short, and each is furnished with only two
sublateral parallel tubercles, which are surmounted by nu-
merous small, bead-like tubercles. The superior antenne
are not half the length of the animal. The inferior
antenne are not longer than the peduncle of the superior.
The first pair of legs are small, the hand being ovate
and the palm slightly convex and imperfectly defined.
The second pair of legs articulate with the second seg-
ment of the body, posteriorly to the centre. They have
the hand in the male very large, rounded on the back,
and hollow below (in some specimens we have seen
inflated membranous sacs filling the palm), being defined
posteriorly by a sharp tooth, and armed anteriorly with a
small point that marks the position where the lateral
walls of the palm unite together anteriorly. The finger
is much curved, and armed with two obtuse teeth upon
the inner margin. The three posterior pairs of legs are
of equal length, and adapted for prehensile use.

In the female the tubercles upon the back are less
conspicuous than in the male, and the second pair of legs
have the hand smaller, of an oval form, the palm being
slightly convex, defined by a small process, armed with

CAPRELLA ACANTHIFERA. 67

one or two short, stiff spines. In the young the hand is
nearly of the same form as that of the female, but the
palm is only imperfectly, if at all, defined. Between this
last and that of the male above described, we represent
in our plate four figures, exhibiting various degrees
of development in different individuals of the same
species.*

This species was first excellently figured by M. De
Queronic, as above referred to, from a specimen found
amongst the branches of a Fucus, covered with coral-
lines, in the Bay of Loc Mariaker, on the coast of
Brittany. It has been taken at Plymouth by Mr.
Barlee on Drake’s Island at low water spring-tides, as
well as dredged by ourselves in Plymouth Sound. Mr.
Edward has sent it to us from Banff, the Rev. A. M.
Norman from Northumberland, and we have received it
from Mr. Robertson from Millport. Specimens are also
in the Belfast Museum Collection, obtained by the late
W. Thompson, Esq., who found it amongst Corallina
officinalis, in shallow pools between tide-marks, at Spring-
Vale, County Down, in July, 1846. It is also in the
Bell Collection at Oxford, taken by the Rev. J. Gordon
in the Frith of Forth.

* In the British Museum is preserved a series of this species, to one of the
individuals of which the specific name C. acanthifera is attached in the hand-
writing of Dr. Leach, whose description, —‘‘ Back, especially the hinder part,
spiny ; inner edge of the second pair of hands lunate-excavated,”—is so short
and insufficient as to have led Mr. Spence Bate into the idea that the fol-
lowing species was the true C. acanthifera, and the present one, consequently,
undeseribed. Dr. Leach found his species not uncommon on the Devonshire
coast, and forwarded specimens to Latreille with the MS. name of C. acumi-
nifera, which was adopted by Latreille and Desmarest, the former of whose
descriptions is evidently taken from a male of C. acanthifera. Both these
names have been misapplied by Johnston and R. Q. Couch to the cornuted
females of the following species.

68 CAPRELLID®.

AMPHIPODA. CAPRELIIDA.
ABERRANTI4.

EES Gy .
ffm
iM (=

CAPRELLA TUBERCULATA.

Specific character. Male.—Cephalon not lobed. First two segments of the
pereion long and smooth; the five last shorter and dorsally tuberculated.

Second pair of enathopoda having the propodos long, pubescent; palm defined
by a strong tooth.

Length 3 inch.

Female.—Cephalon surmounted by a tooth, and the pereion dorsally tuber-
culated. Second pair of gnathopoda defined by a small tooth.
Length } inch.

Caprella tuberculata. GurRrtn, Icon. R. An. Crust. pl. xxviii. fig. 1.
Goopsrr, Edin. New Phil. Journ. xxxiil. p.
188, pl. iii. fig. 6. W. Tompson, Ann.
Nat. Hist. xx. p. 244. Spunczn Barn, Ann.
Nat. Hist. 2 ser. xix. p. 151. Wuuts,
Cat. Brit. Crust. p. 60. Pop. Hist. Brit.
Crust. p. 215, pl. xi. fig. 5.

Fem. Caprella acuminifera. Jounston, Mag. Nat. Hist. vi. p. 40. fig. 7a
(not of Latreille and Desmarest).

Fem. Caprella acanthifera, Jounston, Mag. Nat. Hist. viii. p. 671, fig. 70.
R. Q. Coucu, Rep. Penzance, Nat. Hist. Soe.
1852, p. 96 (not of Leach). Sprncz Barz,
Cat. Amph. Brit. Mus. p. 360. pl. Ivii.

fig. 2,

CAPRELLA TUBERCULATA. 69

Tur males are much larger than the females. The
head, instead of being armed with a tooth, is furnished
with a minute tubercle. The first two segments of the
body are very long, and smooth; the second somewhat
hirsute. The third, fourth, and fifth are shorter than
the preceding, and subequal in length; these are all
tuberculated upon the dorsal surface, as are also the
sixth and seventh segments. The tubercles, which are
very insignificant upon the third segment, increase in
size posteriorly, and are very conspicuous upon the three
last segments. The superior antenne reach but little
beyond the first segment of the body. The first joint of
the peduncle is about the same length as the third, but
the second joint is much longer than either. The inferior
antennee reach to the extremity of the second joint of
the peduncle of the superior. ‘The first pair of legs are
very small, and situated quite at the anterior extremity
of the first segment of the body, therefore appear to
be attached to the head. The second pair of legs articu-
late with the second segment of the body at its posterior
extremity. The hand is nearly as long as the second
segment, and hirsute upon the upper margin and palm.
The palm lies nearly parallel with the upper margin for
more than half the length of the hand, where it is
defined by a strong tooth or process. The finger is
furnished upon the inner margin with an obtuse tooth or
pointed tubercle. The last three pairs of legs are short
and robust.

In the female the head is surmounted by a strong tooth,
directed upwards and forwards. The first segment of
the body is short; the second much longer, and tubercu- |
lated; the five remaining segments are tuberculated, the
tubercles increasing in size posteriorly. The second
pair of legs articulate near the anterior extremity of the

70 CAPRELLIDA.

second segment of the body. The hand is ovate, the
palm straight, and defined by a small denticle.

We have received this species from Guernsey, where
it was taken by the Rev. A. M. Norman, and from Mill-
port, N.B., where it was captured by Mr. Robertson.
A considerable number were found by Mr. T, L. Couch
in the crevices of a crab-pot buoy thrown on the coast at
Polperro during a heavy gale in 1854, and Mr. R. Q.
Couch obtained the female at Mount’s Bay, in Gwavas
Lake, and off St. Michael’s Mount, among conferve.
Specimens from the Frith of Forth are contained in the
British Museum Collection.

In the male of this species the form of the palm is
very liable to vary from the character as exhibited in the
female to that of the male, as above described.

It is not hastily that we have come to the conclusion
that the two animals represented above are but sexes of
one species. The animals are from the same locality, and
their distinctive characters do not appear to have a
higher value than such as indicate the sexes of one and
the same species. We have been induced to identify it
with Goodsir’s C. tuberculata by the pointed tooth upon
the head, rather than to associate the latter with C.
hystrix (acuminifera), which also may possibly be but a
variety of this same species.

CAPRELLA AQUILIBRA. yg E

AMPHIPODA. CAPRELLIDA.
ABERRANTIA.

CAPRELLA AQUILIBRA.

Specific character. Male.—Body smooth. First and second segments of
pereion very long, equal to half the length of the animal. Second pair of
gnathopoda articularly at the posterior extremity of the second segment ;
propodos long-ovate ; palm subparallel with the upper margin, armed
anteriorly with a large triangular tooth or process, and a small denticle
immediately posterior to the process.

Length ? inch.

Caprella cequilibra. Spunce Bats, Cat. Amph. Crust. Brit. Mus. p. 362,
pl. Ivii. fig. 5.

Caprella equilibra. Say, Journ. Acad. Philad. i. p. 391.

Caprella Januarit. Kroyer, Nat. Tidssk. iv. p. 499, pl. vi. fig. 14-20.
Voy. en Scand. pl. vi. fig. 15. Dawa, U.S. Explor.
Exped. p. 819, pl]. lv. fig. 2.

72 CAPRELLIDZ.

THE body of this animal is smooth. The head is
round and unarmed. ‘The first segment of the body
is very long, cylindrical, and slender. The second seg-
ment is as long as the first, and resembles it, except
that as the first gradually lessens in diameter pos-
teriorly, the second as gradually increases posteriorly,
and is armed inferiorly, in the ventral median line, with
a long straight tooth, between the articulations of the
second pair of arms. These two segments, with the
head, occupy half the length of the animal. ‘The
remaining five segments of the body are, therefore,
shorter than in the majority of the species of this genus.
The superior antenne are not half the length of the
animal; the first joint of the peduncle is longer than
the head ; the second more than twice the length of the
first; the third about half the length of the second, and
does not taper at the extremity: the flagellum is about
half the length of the third joint of the peduncle, and
half the diameter at the base. The inferior antennz are
not half the length of the superior. The first pair of
legs are very small, and situated at the extreme anterior
limit of the first segment of the body, therefore close to
the head. The second pair of legs articulate with the
second segment near the posterior extremity, conse-
quently are situated about the centre of the animal, a
circumstance from which we presume that Say gave the
animal its specific name; the hand is long, and some-
what oval in its general form, but the palm, which is
defined by a small tooth, is straight, running nearly
parallel with the upper margin, and occupying about
two-thirds the entire length of the hand, which is more
than half the length of the second segment of the body ;
the palm is armed at the anterior extremity with an
acute tubercle or short tooth and a small denticle (which,

CAPRELLA MQUILIBRA. 73

Say says, is not constant), situated immediately posterior
to the process. The last three pairs of legs are very
short.

Having had the opportunity of comparing our British
specimens with that presented to the British Museum by
Mr. Say, we are enabled to assert their identity, and we
are not able to detect any character by which this species
differs from C. Januari, as described by Dana and
Kroéyer. We have also seen specimens from Hong-kong,
and are unable, by the closest observation, to discover
any difference between them.

The geographical range of this species is, therefore,
very great. In our own country we took it first amongst
weeds attached to one of the buoys in Plymouth Sound.
It has since been sent to us from Seaham by the Rey.
A. M. Norman, who has also taken it at Cullercoats. But
Kr6yer’s type came from Rio Janeiro, while Dana’s
specimens were procured from an anchor in from ten to
twelve fathoms of water, also at Rio Janeiro. Mr.
Harington has sent specimens to the British Museum,
which he procured at Hong Kong, and Say found his
specimens ‘‘very common in the bay of Charleston,
particularly at Sullivan’s Island, on the two species of
Gorgonia, so common in the salt-water creeks of the
southern coast.”

74, CAPRELLIDA.

AMPHIPODA. CAPRELLIDA.
ABERRANTTIA.

CAPRELLA SPINULATA.

Specific character. ‘‘ Long and slender; head deeper than the other
annulations. Head without a spine, but all the other annulations with one
or more dorsal spines.”’

Caprella spinulata. R. Q. Coucn, in Report Penzance Nat. Hist. Soc. 1852,
p. 98.

‘* Lone and slender. The head is larger than the next
articulation, and without a spine; the occipital articula-
tion with a spine near its posterior margin ; and there is
one on the next ring above the branchiz. There are
two on the third, one above the branchiz, one near its
posterior margin, and one in the centre of each of the
others. Superior antenne as long as the body; basal
joint small; the second about four times as long as wide ;
the third long and slender, and slightly enlarged towards
its distal extremity, the last multi-articulate and ciliated.
The inferior antenne much smaller than the others. At
the lower part of the head two pedi-palpi, small and
bifid at their extremities. The hand very large; move-
able joint long, slender, and hooked, and at its point,
when bent, touches a spine on the hand.”

Taken by Mr. R. Q. Couch (whose recent death we
have to deplore) in a pool among conferve, Lariggan
Rocks, Mount’s Bay, Cornwall, from whose description
in the work above quoted we make this extract, regret-
ting that we are unable to give a representation of this
species.

CAPRELLA TYPICA. 75

AMPHIPODA, CAPRELLIDA.
ABERRANTLIA.

CAPRELLA TYPICA.

Specific character. Body entirely smooth, and destitute of spines in both
sexes. Second segment of the body short and deep. Second pair of
gnathopoda with the hand large and curved, armed at the base of the palm
(defined by a strong obtuse tooth) with a robust recurved spine. Antenne
moderately long and slender; hind legs slender, with the hand simple.

Length } inch.

Podalirius typicus. Kroyer, Nat. Tidssk. 2nd Ser. i. p. 283. Voy. en
Scand. pl. xxv. fig, 1 a—l. Sprncu Bare, Cat.
Amph. Brit. Mus. p. 354, pl. lvi. fig. 2.

Tuis species has been formed by Kroyer into a sepa-
rate genus, named Podalirius, in consequence of the very
rudimental condition of the abdominal portion, of which
none of the appendages are developed (Fig. P). It
resembles C. linearis, but is more robust, the head and
second segment of the body being deeper and shorter
than in that species. The antenne are slender: the
superior in the male are nearly twice as long as the
inferior, the peduncle of which scarcely reaches to the
extremity of the second joint of the superior; the flagel-
lum of the latter being composed of very few articuli.
In the female the peduncle of the lower antenne appa-
rently extends as far as the extremity of the peduncle of
the superior, which is, however, mutilated in our unique

76 CAPRELLID ©.

specimen of this sex. The males are also at once distin-
guished by the peculiar form of the hand of the second
pair of legs, which is of large size, strongly curved on
its fore margin, whilst the posterior, or palm, is exca-
vated; its distal extremity broadly but obliquely trun-
cate, whilst its base is armed with an obtuse point,
antagonizing with the tip of the finger, followed by a
strong bent and recurved tooth. The first pair of legs
are small, and the hand oblong-ovate ; this is also the
form of the hands of the second pair of legs in the
female, but the base of the palm is defined by a conical
point near to the base of the joint.

Our specimens (like those of Kréyer) have also lost the
antepenultimate pair of legs, but in the two posterior
pairs the joints are slender, naked, and destitute of spines
or points, so as to appear quite simple.

Several specimens of this species, collected by the
Rev. J. Gordon in the Frith of Forth, exist in the Bell
Collection of Crustacea, recently presented to the Uni-
versity Museum of Oxford by Professor Westwood.
They were obtained upon a shell brought up on a Heke
dock line on the 18th September, 1855.

CYAMID/.

“I
“

Fam. II].—CYAMIDZE.

Body flat. Cephalon cylindrical, tapering, anchylosed
with the first segment of the pereion. The latter broad,
depressed, with the segments laterally wide apart. Pleon
rudimentary. Eyes posterior to the superior antennae, of
which the flagellum is indistinctly articulated. Inferior
antennze minute, inserted between the upper pair and
the labrum. Gnathopoda subchelate. Pereiopeda
flat, broad, and furnished with strongly-hooked dactyla,
wanting to the third and fourth segments of the body,
which are furnished with elongated branchie.

This family consists of a single genus, the species of
which are parasitic upon the cetaceous animals. They
are of moderate size, and are able, by means of the strong
hooks with which their legs are terminated, to affix them-
selves firmly to their prey. The head is small, oblong, and
cylindrical, soldered to the first segment of the body,
which is dilated at its sides, giving this part of the animal
a pear-shaped appearance. The antennz are affixed to
the anterior and superior extremity of the head. The
upper pair are of moderate size; the peduncle composed
of three nearly equal-sized joints, followed by a small,
indistinctly-articulated flagellum. The inferior pair are
very small, and terminate in a small conical, apparently
uni-articulate flagellum. Immediately beneath these lat-
ter appendages is a small tubercle, which is homologous
with the olfactory organ of the normal Amphipoda. ‘The
mouth is small, and placed at the infero-anterior extremity
of the head: it consists, according to Savigny, of a

78 CYAMIDA.

labrum, rounded at the sides, but emarginate in front;
a pair of mandibles, bifid and denticulated at the tip,
but destitute of a palpus; a first pair of maxilla, com-
posed of a single lobe; a second pair of maxille, much
smaller than and inserted between the first pair, upon a
common base, and each bearing a very minute two-pointed
palpus; a labium, composed of two outer lobes and two
inner minute ones (representing the four maxilla), and
a large maxillary outer labium, furnished with a pair of
five-jointed palpi.

Independent of the first articulation of the body, sol-
dered to the head, the animal consists of six flattened
segments, of which the middle ones are the broadest.
They are separated widely from each other at the sides,
and the last is terminated by a minute rudimental tail.
The segment attached to the head supports on its under-
side a pair of small legs, generally folded beneath the
body, composed of four joints, terminated by a subcheli-
form hand and a slender, curved finger. The following
segment of the body bears a large and powerful pair of
legs, although they possess one joint fewer than the
hinder pairs. The hand is broad and flattened, and the
finger curved and acute at the tip. The third and
fourth segments of the body are destitute of legs, but
their place is supplied by a pair of elongated, cylindrical,
branchial appendages, in some species being as long as
the legs themselves, generally turned over the back of the
animal. Sometimes these are simple, but in other cases
they are double, and at their base in the male is to
be observed one or two small corneous points. In the
female these two segments of the body bear two large
ovigerous scales, affixed at the base of the four branchial
appendages. The fifth, sixth, and seventh segments of
the body respectively bear a pair of legs nearly similar in

CYAMIDE. 79

shape and size to those of the second segment, but com-
posed of five joints, the coxz being soldered to the seg-
ments to which they are attached. The tail is very
minute and rudimental: on its underside in the male are
perceived two pairs of slender, deflexed, horny append-
ages; each of the two preceding segments being armed on
the ventral surface with a pair of strong spines. In the
female the antepenultimate segment of the body is fur-
nished on its under-surface with two small transverse
valves, uniting into a tubercle, which closes the orifice of
the generative organs.

The analogy which these animals exhibit with the
Pediculi among hexapod insects, and with Pycnogonum
amongst the Arachnida, merits attention.

MEN TARRING A BOAT.

80 CYAMIDA,

AMPHIPODA. CYAMIDA.
ABERRANTIA.

Genus—CYAMUS.

Cyamus. Lamarck, Syst. d. Anim. sans Vert. p. 166. Larreriue, Hist.
Nat. Crust., &c., vi. p. 328. Desmarest, Cons. Crust.
p- 279.

Larunda. Unacu, Trans. Linn. Soc. xi. p. 363. SAmovELLE, Ent. Comp.
p. 106.

Panope. Luacu, Edin. Encye. vii. p. 404.

Generic character. Head and first segment of the body
fused into a pear-shaped mass. Eyes small and vertical.
Segments of the pereion with the sides horizontally dilated;
the legs attached to the postero-lateral margins ; five pairs of
strongly subcheliform legs, wanting in the third and fourth
segments, which are furnished with two pairs of branchial
appendages, long and filiform. Pleon rudimental.

THESE animals affix themselves by means of their
strong legs upon the rough portions of the bodies of
cetaceous animals upon which they feed; the different
species appear to affect particular portions of the bodies
of these animals, some being found massed together
upon the head, others are more erratic, or affix themselves
to the fins, organs of generation and folds of the flesh.
The males are larger than the females, upon which they
affix themselves by means of the strong hooks of their
feet as do the Gammari. The young remain for a con-
siderable time attached to the female parent, nestling in
the ovigerous pouch or rambling over her body. Their
interior structure, as observed by Treviranus and Roussel
de Vauzeme, closely approaches that of the Isopoda, the
nervous system consisting of eight bilobed ganglions
exclusive of the supra-cesophageal, each segment of the
body being provided with a ganglion.

CYAMUS. 81

These creatures crawl but slowly, digging the hooks of
their feet into the skin of the whale to the base of the
claws, whence it is difficult to detach them by force,
without cutting through the epidermis, when they are
freed ; it is also dangerous to attempt their removal, as
their strong claws easily penetrate the fingers, and cause
considerable pain. ‘Their branchiz are brought together
on the back, and directed forwards, except in EL. gracilis,
which carries them in the opposite direction. When de-
tached, and placed in sea-water, they are unable to swim,
neither their branchiee nor limbs enabling them to perform
such an operation. Whena whale is hoisted on board-ship,
the Cyami attached to it extend their branchiz, agitate
their antenne and hooked legs, as if desirous to seize
something else. If the branchiz are cut, the animals do
not appear to be affected, but when the antennez are
similarly treated, the animals move about irregularly,
from side to side and backwards, as if drunk. When
injured, the branchiz are never renewed ; but if the legs
are broken off at the base, new limbs are produced ; but
this is not the case if only a portion of the leg be injured:
hence it is not unusual to meet with Cyami having one or
more legs of smaller size than the rest.

M. Roussel did not observe any species of Cyamus on
the dolphin, cachalot, or “ baleine a ailerons.” He states
that it is generally believed by the fishermen that the alba-
trosses, which abound about the fishing stations, pick the
Cyami off the bodies of the whales, but he had never
found any of these crustacea in the stomachs of such
specimens of these birds as he had dissected.

The structure of the mouth and intestinal canal of the
g, and not a
suctorial, animal. Indeed, on opening its alimentary

Cyamus sufficiently prove it to be a gnawin

VOL. Il. G

82 CYAMIDA.

canal small portions of the skin of the whale are found
in it, and on removing the Cyamus from the whale, the
epidermis, whence it is taken, is found to have been
gnawed off.

The eggs of the Cyami are spherical, agglomerated,
and of a yellowish-white colour: they are deposited in
the ventral pouch, which is formed of thin mem-
branous plates, ciliated along the margin, and here the
young are hatched and carried until they are fully
developed. Whilst the eggs remain in the incubatory
pouch, the female detaches herself from her companions,
rejoining them when she had got rid of her young brood.
The young ones are complete in all their parts; the head,
however, is proportionally of an enlarged size, the bran-
chize globular, the anterior pair of legs not much smaller
than the following, and the antenne short. There ap-
pears, according to M. Roussel de Vauzeme, considerable
difference in the treatment of the young brood by their
parents. The females of C. ovalis arrange themselves
side by side on the tubercles of the head of the whale,
covering their young with their bodies, which form
strong shields for their protection. In C. gracilis, on the
contrary, the females and males, as well as young, are
mixed together, whilst the young of C. erraticus are found
isolated and fixed on the different parts of the body
where they had been left by their parents; but in ac-
cordance with their future mode of life, M. Roussel
gives a curious instance of the effect of the distinction of
habits in the different species of this genus: in answer
to an inquiry by Messrs. Audouin and Milne Edwards,
as to whether Cyamis gracilis might not be the young
state of C. ovalis, M. Roussel relied on the different
habits and colour, as well as the particular form of the

CYAMUS. 83

body, whilst out of several hundred Cyami preserved in
the collections at the Jardin des Plants he was only able
to detect a single individual of C. erraticus, the mode of
life of that species not rendering it so apparent to the
collector as the species which associate together in vast
numbers on prominent parts of the body.

From the further observations, both of Martens and
Roussel de Vauzeme, it would appear that the violent
storms of the winter season are very destructive to the
Cyami, many of the parts of the whales generally in-
fested by them being then free; those which survive
being feeble and discoloured. He only observed C. er-
raticus to preserve its rosy tint, but its numbers were also
diminished.

The relations of the Cyami with other Edriophthalmous
Crustacea are very interesting. Placed by Linnzus,
Pallas, and Miller amongst the Onisci, and arranged by
Fabricius with the Ase/li and Cymothoe, their relationship
with the order Jsopoda was indicated; and M. Roussel de
Vauzeme, the author of an elaborate memoir on the
genus in the ‘‘ Annales des Sciences Naturelles” (2° Sér.
vol. i.), maintained their nearer approach to the Isopods
than to any other Crustacea. Latreille, at first, placed
the genus with the Gammari, in the order Amphipoda,
but he subsequently united it with Caprella, to form the
distinct order Lemodipoda; nor can we doubt (notwith-
standing the objection of M. Roussel, founded on the
variations in the mode of insertion of what he terms the
fore legs) that this is the legitimate position of the
genus; in fact, Caprella is but a laterally compressed
Cyamus, and but little imagination is required to con-
vert the former into an excessively attenuated Cyamus, so
perfectly similar is the disposition of the segments of the
body and limbs in both animals.

84: CYAMIDA.

Savigny (as Fabricius had, indeed, previously done)
pointed out a supposed affinity of Cyamus with Pycno-
gonum ; and Strauss, having their parasitic habits in view,
proposed to unite them with Nymphon, Cecrops, Pycno-
gonum, Dichelestion, &c., into a most heterogeneous group
under the name of Crustacea Parasita.

CAPTURE OF A WHALE.

CYAMUS CETI. 85

AMPHIPODA, CYAMIDA.
ABERRANTIA.

CYAMUS CETI.

The Whale Louse.

Specific character. Body depressed, elliptical, segments gaping at the
sides (male narrower ?). Third and fourth segments of the body with one
long branchia on each side ; armed at the base with two short appendages ;
second pair of hands armed beneath with two obtuse teeth, between which
is a lunate incision.

Length nearly half an inch.

Pediculus Ceti. Martens, Voy. Spitzbergen, viii. tab. ix. fp (1671).
Linnaus, Fauna Suecica, p. 499, No. 2056 (Onvs-
cus C.). Syst. Nat. ii. p. 1060. Sepa, Thesaurus,
t. i. pl. xe. fig. 5. Panuas, Spicilegia Zool. fasc. 9,
pl. iv. fig. 14, 4 Bo. Ds GuErR, Mém. t. vii.
pl. xlii. figs. 6, 7 (Squille de la Baleine). Faxnicrvs,
Ent. Syst. Suppl. p. 570 (Pycnogonum C.).
Lamarck, Syst. Ann. s. Vertebr. p. 166 (Cyamus C.).
Minter, Zool. Dan. iii. pl. cxix. figs. 18-17

86 CYAMID &.

Bosc. Hist. Crust. ii. pl. xvi. fig. 2. Saviany,
Mem. i, pl. v. Larreiie, Hist. n. Crust. &e. vi.
p. 331, pl. lii. fig. 4. Genera Ins. t. i. pp. 60, 176.
DrsMArEsT, Cons. Crust. p. 280, pl. xlvi. fig. 4.
Wuite, Pop. Hist. Brit. Crust. p. 219, pl. xi.
fig. 6. Cat. Brit. Crust. p. 62. Spence Bars,
Cat. Amph. Brit. Mus. p. 366, pl. lviii. fig. 2. Ann.
Nat. Hist. Feb. 7, 1857. Leacu, Edinb. Ene. vii.
p. 404 (Panope Ceti). Trans. Linn. Soe. xi. p. 364
(Larunda C.). Suppl. Ene. Brit. i. p. 426, pl. xxi.
SAMOUELLE, Ent. Comp. p. 106. M. Epwarps, Hist.
d. Crust. iii, p. 118. Treviranus Verm. Schrift, ii.
p. 1. Die Wallfischlaus, pl. i.

Cyamus erraticus. | RousseL DE Vauzeme, Ann. Sc. Nat. 2nd Ser. t. i.
p. 259, pl. viii. fig. 22, 28. Minne Epwarps, Hist.
N. Crust. iii. p. 118. Gossx, Mar. Zool. i. p. 131
(not of Spence Bate, Cat. Amph. Brit. Mus. p. 368).

ALTHOUGH the early descriptions of the whale louse, of
which, until recently, it was supposed that there was but
a single species, are vague, the figures and locality suffi-
ciently indicate that the creature, so beautifully figured
by Savigny, in the first volume of his ‘“ Mémoires,” and
which is identical with the one represented in the above
woodcut, was the species intended by Linnzus, De Geer,
&c., the early representations of which exhibit only a
single linear appendage attached on each side of the third
and fourth segments of the body. We presume likewise,
and are confirmed herein by M. Milne Edwards, that the
C. erraticus of M. Roussel de Vauzeme is intended for the
same species ; his figure probably, from its narrower size,
representing a male. The fact of several distinct species
having been found to infest the whale, was doubtless the
reason which induced the last-named observer to sink the
specific name Ce#z as of generic extent; but this principle
is at variance with the rules of the best zoological no-
menclaturists. By some oversight, Mr. Spence Bate, in
his work on the Amphipoda (pp. 566, 368), has given
C. ceti and erraticus as distinct species, referring, under

CYAMUS CETI. 87

the former, to M. Milne Edwards, who, however, rejects
the Linnean specific name Ceti. The animal represented
by the former (Plate 58, fig. 2) from Talcahuna, in the Paris
Museum, appears to be a male, being much more slender
than the specimens represented by Savigny, and in our
woodcut. The head is oval, its hinder portion being
connate with the first segment of the body, of which the
central portion is much shortened, the sides swelling
into rounded lobes. The upper antenne ()) are about
twice the length of the head; the first, second, and third
joints of nearly equal length; the first being the thickest
and somewhat triquetrous, the terminal joint is minute
and conical. The lower antenne (c) are very minute and
slender, not being more than one-third of the length of
the basal joint of the superior, with four joints, the third
being the longest, and the fourth very minute. The
upper lip (*), copied from Savigny, is rounded at the
base and slightly emarginate in the middle of its fore
margin, whilst the tongue (**) is somewhat four-lobed,
or rather it is deeply incised in the middle of its fore
margin, and is furnished in the centre with a narrow
bipartite projection, shorter than the lateral lobes.
The mandibles (d) are somewhat triangular, destitute of
a palpiform appendage, but furnished with a separate
denticulated tooth below the extremity, which is similar
in character: the first and second maxille are affixed on
the same plane (as in the Myriapoda, although not sol-
dered into one piece as in that order): the first pair (e)
are large and flattened, apparently three-jointed and des-
titute of palpi, the terminal joint being large, rounded
at the outside of its extremity, with several hairs forming
a brush in the middle of the convex side; the second pair
of maxillz (f) are minute, and apparently three-jointed,
the second and third joints being very minute; they are

88 CYAMID A.

affixed upon a common, elongated basal piece, inserted
betwen the basal joints of the first pair, and the mouth
is closed below by a transverse piece (fig. g), emarginate
in its fore margin, which Savigny terms a “ lévre auxiliare
sans lobes,” but which we regard as the ventral surface of
the segment that carries the pair of foot-jaws (which are
attached at its sides); these are five-jointed, the fourth
being the largest.

The first segment of the body is small, with the front
part rounded on its upper edge, its lower being dilated
in the middle into an angle.

The second segment is much longer than either of
the two following, its fore margin is nearly straight,
having a very minute rounded prominence towards each
of its lateral anterior angles; it is deeply channeled
across its centre. The legs attached to this segment are
very large and broad, the second joint strongly angulated
on its upper edge, the small third joint rounded and
prominent on its lower edge, and the fourth joint with a
moderate semi-lunate impression on its lower edge. The
third and fourth segments of the body are very short,
the fourth having its sides produced at the posterior
lateral angles, whilst its hinder margin is emarginate on
each side. The fifth, sixth, and seventh segments are
each as long as the second, but gradually narrowed, their
fore and hind margins are sinuated, leaving spaces be-
tween the joints. The legs attached to these three seg-
ments are nearly uniform in size, large and broad, with
the fourth joint somewhat conical, having the upper edge
rounded; the terminal joint in all the legs is very acute,
curved, and as long as the preceding joint, thus giving
the animal strong powers of prehension. The tail is
very minute and rudimental. The full-grown female
has the body wider than the male, and has the third and

CYAMUS CETIT. 89

fourth segments furnished with large foliaceous plates,
forming an incubatory sac.

We have no precise details of the locality and notice
of capture of this species beyond the general statement
of its being found on the whale in the British seas.
British specimens exist, however, in the British Museum,
as well as in the Hopeian, Stephensian and Westwoodian
collections, now in the Oxford Museum, &c.

On some of the females which we have examined, we
have found the young fixed firmly to different parts of
the body, about one-twelfth of an inch long, distin-
guished from their parents by the proportionally larger
size of the head (with which the following segment is
confluent), the shorter antenna, and especially by the
size of the first pairs of legs, which are equal to the
following, all being small, and much less strongly dilated
than in the adult state, and also by the small rudimental
size of the branchie.

M. Roussel de Vauzeme informs us that the species of
Cyamus to which he gives the name of C. erraticus, and
which we have regarded as the true Linnean C. cetz,
differs considerably in its habits from the other species
of the genus which he had observed. ‘The former species
attaches itself at the base of the tubercles of the different
parts of the head, fixed upon the smooth skin in the inter-
vals between them, and but rarely mingling with Cyamus
ovalis. They, however, wander about over different parts
of the body, or hide themselves in the folds of the eye-
brows, the commissure of the lips, navel, genital and
anal parts. They also especially attach themselves to
wounded parts of the body, and on one occasion
M. Roussel found a whale injured by the swordfish, the
suppurating wound of which had attracted a vast number
of individuals of this species. The structure of the

90 CYAMIDA.,

body and limbs of this species, indeed, are eminently
fitted for its wandering mode of life; its more slender
body, with longer hooks to the claw-legs, enabling it to
withstand the shock of the waves on the naked parts of
the body of the whale, whereas the structure of the legs
of C. gracilis compel it to a sedentary mode of life.

CYAMUS CETI, YOUNG.

CYAMUS OVALIS. 91

AMPHIPODA. CYAMIDZ.
ABERRANTTA.

CYAMUS OVALIS.,

Specific character. Body depressed, elliptic-ovate, with the segments not
gaping apart at the sides. Third and fourth segments of body, with two pairs
of branchie on each side, of unequal length ; those of the third segment
having at the base only a short slender appendage, those of the fourth seg-
ment having two appendages of unequal size at the base. Hand of the
second pair of legs with two obtuse teeth.

Length about half an inch.

Cyamus ovalis. Roussnu pE VAuzemE. Ann. Sci. Nat. 2nd ser. vol. i.
p. 259, pl. 8, fig. 1-21. Minne Epwarps, Hist. N.
Crust. iii. p. 113. Ann. Sci. Nat. 2nd ser. iii. pl. 14,
fig. 13, 14. Reégne An. ed. Crochard Crust. pl. 63,
fig. 8. GuRIN, Icon. R. An. Crust. pl. xxvili. fig. 4.
Waiter, Pop. Hist. Brit. Crust. p. 219. Cat. Brit.
Crust., p. 62. Gossr, Marine Zool. i. p. 31. SpENcE
Barr, Cat. Amph. Brit. Mus. p. 367, pl. lviii. fig. 3.
Ann. Nat. Hist. (Feb. 1857), 2nd ser. xix. p. 152.

THis species is indicated as British by Mr. Adam
White in his ** Catalogue of the British Crustacea,” but
we have seen no specimen which we are able to identify
with M. Roussel de Vauzeme’s figures, which we have
consequently been under the necessity of copying in the
accompanying woodcut.* This species is at once distin-
guished from C. ceti by its elliptic-ovate form, by the

* The figure on the right hand represents the male, seen on its ventral
surface, whilst the left-hand figure represents the under surface of the body
of the female, showing the incubatory pouch.

92 CYAMIDA”.

segments being not wide apart at the lateral margins, and
by the possession of two slender filiform branchiz at-
tached to each side of the third and fourth segments of
the body. The species represented by Mr. Spence Bate
(Plate 58, fig. 3) is from the Cape of Good Hope, and
possesses a very strong tooth near the extremity of the
fourth joint of the second pair of legs. We presume,
notwithstanding its locality, that it is identical with
M. Roussel de Vauzeme’s species. The branchial ap-
pendages of the males are longer than those of the
females. In the species before us the anterior pair are
furnished at the base with a single pointed appendage,
whilst the posterior pair have this appendage doubled, its
branches being rather unequal in size; these appendages
exist in the female in the modified form of large flat-
tened plates, or valves, extending beneath the middle of
the body. These plates are concave, pedunculated,
fringed at the edges, and formed of a double transparent
membrane: thus constituting a sac without an external
orifice. ‘These plates, lying upon each other, serve as a
pouch, within which the eggs are deposited, and the
young hatched. Some uncertainty has been entertained
as to the real nature of the branchial appendages, which
have been regarded as simple stems, false legs, pseudo-
branchiz, vesicles without determinate use, and organs of
respiration ; but the direct observation of M. Roussel
on the living animals has demonstrated that they are
branchial canals in communication with the dorsal vessel,
and of a membranous texture, whilst the appendages at
their bases in the male are differently organized, being
crustaceous, and unfitted for organs of respiration; and
the plates of the ovigerous pouch in the female are also
destitute of branchial canals, and consequently unable to
perform the functions of gills.

CYAMUS OVALIS. 93

According, also, to M. Roussel de Vauzeme, Cyamus
ovalis, as well as C. gracilis, are only found upon the tu-
bercles of the chin, lips, and upper jaw of the whale, and
especially upon the larger tubercle of the head, which
the whale-fishers call the crown, near the blow-holes, and
the horny excrescences with which it is surrounded.
Sometimes, indeed, C. ovalis is found in such vast num-
bers in this last situation, that at a considerable distance
the patch of white colour, produced by their presence,
may be observed when the whale comes to the surface to
breathe. In this situation the individuals of C. ovalis
arrange themselves with considerable regularity, by
which they are distinguished from C, gracilis, which are
scattered about more irregularly.

The young of C. ovalis, as figured by M. Guérin
Meéneville, in the “ Iconographie du Régne Animal,” is
more regularly elongate-ovate than the young of C. cetz, as
figured above by ourselves, with the legs almost cylin-
drical, the fourth joint but moderately dilated ; indeed,
according to M. Milne Edwards (Ann. Sci. Nat. vol. 111.
p- 329), “Les jeunes Cyamus ont une forme suelte et
elancée,” all the segments being perfectly alike, re-
sembling portions of a cylinder with the legs ‘‘ gréles,

)

cylindriques, et parfaitement extensibles;” and with the
branchial vesicles not more developed than in Proto,

Caprella, &c.

94, CYAMIDA.

AMPHIPODA.,. CYAMID.
ABERRANTIA.

CYAMUS GRACILIS.

Specific character. Body small, oblong ; segmerts of the body emarginate
at their lateral margins. Third and fourth segments of the body with a
pedunculated branchia on each side, each furnished at its base with two very
short appendages. Second pair of hands with the palm slightly concave.

Length 3 inch.

Cyamus gracilis. Rousset pE VauzemE, Ann. Sci. Nat. 2nd ser. vol. i.
p. 248, pl. 8, fig. 24, 25. Mrin~nr Epwarps, Hist. N.
Crust. iii. p. 113. Spence Barz, Cat. Amph. Brit.
Mus. p. 366, pl. lviii. fig. 1. Gossn, Mar. Zool. i.
p. 131. Wutrn, Pop. Hist. Brit. Crust. p. 219.

Our figures of this species represent, firstly (the cen-
tral figure), the animal as drawn of the natural size by
M. Roussel de Vauzeme; secondly (the right-hand
figure), a copy of Mr. Spence Bate’s figure (PI. 58,
fig. 1), drawn from individuals in the Paris Museum,
found at the Cape of Good Hope, and also taken during
the voyage of the Chevrotte, but without any indication of
locality; and thirdly (the left hand-figure), an animal
in the British Museum, to which the same name has
been applied, and which is stated by Mr. Adam White
to inhabit the British seas ; it is evidently an individual
in an immature state, having minute antenna, and the

CYAMUS GRACILIS. 95

first pair of legs of moderately large size, although smaller
than the following limbs. The species, according to
M. Roussel de Vauzeme, has the body small and oblong,
with a single branchia attached to each side of the third
and fourth segments, each branchia having two very short
appendages at its base, and the second pair of legs have
the large penultimate joint with a slight concave impres-
sion on their under surface. We regret that our igno-
rance of the precise locality of the supposed British
specimen above mentioned, and its immature condition,
as well as the very concise notice of this species by
M. Roussel himself, prevent us from giving a satisfactory
account of it. The only notice of its habits, as distinct
from those of C. ovalis, has been already detailed by us
in our account of the last-named species.

96 CYAMID.

AMPHIPODA. CYAMIDG.
ABERRANIIA.

CYAMUS THOMPSONI.

Speciic character. Head triangular; antenne very short; two middle
segments of body narrower than the preceding and following. First and
second pairs of legs equal in size, and not larger than the posterior pairs.
Third and fourth segments with a single very short oval branchia on each
side.

Length about one-sixth of an inch.

Cyamus Thompsoni. GossE, Mar. Zool. i. p. 131. Ann. Nat. Hist. xvi.
p- 30, pl. iii. fig. 11 (1855). Warr, Pop. Hist.
Crust. p. 219, fig. 225.

Cyamus Thomsoni. Spence Barr, Cat. Amph. Brit. Mus. p. 368,
pl. lviii. fig. 5. Ann. Nat. 2nd ser. xx. p. 525
(Jan. 1858).

« Cyamus Delphinii. Guirin Mbnevittr, Iconogr. R. An. Crust. texte

p. 25, pl. xxviii. fig. 5 (adult state ?)

Cyamus gracilis, SprncE Batr, Ann. Nat. Hist. 2nd ser. xix. p. 152
(Feb. 1857).

THe animal which forms the type of Mr. Gosse’s
species is fortunately preserved in the British Museum
collection, and has served us for the accompanying figure.
It is evidently in an immature state, as shown by the
small size of the antennze, the uniform size of the legs,
and the rudimental condition of the branchiz ; the legs,
however, are considerably stronger than in the young

CYAMUS THOMPSONI. 97

of C. ceti, which we have represented in our figures in
page 90; and in all, the penultimate joint is large and
angulated in the middle of its lower edge.

The specimen was obtained by Mr. William Thomp-
son, of Weymouth, attached to an individual of Hy-
peroodon bidens captured in Portland Roads in 1854,
This is the species referred to by Mr. Spence Bate in
the ‘‘ Annals of Natural History,” for February, 1857,
2nd Series, under the name “ C.,

?C. gracilis.
Gosse,”’ as stated by Mr. Bate himself in the same work,
2nd Series, vol. xx. p. 525, where it is referred to
C. Thomsoni [Thompsoni]. Gosse, * Ann. Nat. Hist.,”
vol. xviii. [xvi.] 1855.

In our introductory observations on the genus, we
have seen that M. Roussel de Vauzeme had not observed
any species of this genus on any of the dolphins; but
the capture of this specimen by Mr. Gosse disproves
such a statement, whilst M. Guérin Meéneville, in his
*‘Tconographie du Reéegne Animal,’’* has described and
_ figured a species under the name of C. delphinii, taken
upon the generative organs of the dolphin on the coast
of the Antilles. It is of an oval-elongated form, with
the segments of the body touching each other at the
sides except the terminal ones, which are a little gaping.
The great joint of the second legs bears a strong tooth on
its under edge, the branchial filaments (one on each side
of the third and fourth segments) are very short, and
much shorter than the legs. The basal articulations of
the hind legs are strongly dentated and various in form.
Mr. Spence Bate (Cat. Amph. p. 366) considers this
species to be only a variety of C. gracilis. It has, how-
ever, to be determined whether the animal is uniform
in its residence on the dolphin, or only exceptional, as

* Crust. texte, p. 25.

VOL. I, Hi

98 CYAMIDA.

appears probable from the absence of specimens; if
the former be the case we should not hesitate to regard it
as a distinct species, of which the precise characters have
to be detailed. How far, also, it is identical with Mr.
Gosse’s animal must be left for future determination,
when the immature states of C. delphinii shall have been
ascertained.

OYAMUS DELPHINII, G. M., MALE AND FEMALE.

ISOPODA. 99

Order—ISOPODA.

Tus order of Crustacea was first defined by Latreille,
and was named Isopoda, in contradistinction to the Am-
phipoda, from the Greek words tooc, equal, and wédec,
feet, in allusion to the general conformity in size and
function of the seven pairs of legs, the two anterior
pairs of which, as in the Amphipods, are the homologues
of the two outer pairs of foot-jaws of the Decapod Crus-
taceans. If we were to adopt the ideas of some writers,
that large size constituted the especial character of a
typical group, we should be compelled to regard the last-
named animals as the types of the class Crustacea, and
should be, consequently, obliged to consider the Isopods
as further removed from the type than the Amphipods,
in consequence of the former being destitute of branchial
appendages, in the shape of vesicles, affixed to the base
of the legs (a character which constitutes a marked dis-
tinction between the two orders which form the subjects
of this work), and by the possession of which the Am-
phipoda are more nearly approximated to the Decapoda.
If, on the other hand, the type of the articulated class of
animals is to be sought for in such members as present a
more regularly articulated body, each articulation being
furnished with a pair of equal-sized articulated limbs,
we must consider the animals of the present order as
more typical of the Crustacean class than the Amphipoda.
In immediate connection with the character derived from
the want of branchial appendages attached to the base

H 2

100 ISOPODA.

of the legs, is that presented by the structure of the
appendages of the tail, which in the Isopods support
organs of respiration, varying considerably in their for-
mation in the different groups, instead of serving, as in
the Amphipods, for purposes chiefly of locomotion.

Another character which was employed by Latreille to
distinguish the majority of these animals from the Am-
phipoda, namely, the want of an articulated appendage to
the hard horny mandibles, is by no means a constant one,
since although the Idoteidz, Oniscide, and Anceidz are
destitute of such an appendage, it occurs in the Asellita,
Sphzromide, and Cymotheidz (of which last we possess
no hitherto recorded representative in these islands).

With the Amphipoda the Isopoda are closely connected
through the aberrant families of each order.

In the genus Cyamus the lowest form of Amphipod
with which we are at present acquainted, the Isopodal
appearance is very considerable ; so great indeed that at
one time the genus was grouped with this order; and,
in fact, it can only be separated from it by virtue of the
branchial organs that are attached to the body ; and even
these are reduced to two pairs only. In Cyamus also (as
in the Caprellz), the head is confluent with the first seg-
ment of the body, and the tail is reduced to a rudimen-
tary condition.

If we turn to the genus Tanais, among the aberrant
Isopods, we have an animal that is capable of being se-
parated from the Amphipoda only by virtue of its caudal
appendages. The head in this genus is confluent with
the first segment of the body; and a pair of branchial
vesicles (organs especially characteristic of the true Am-
phipoda) are attached to the third pair of pereiopoda (or
fifth pair of feet), and the natatory or tail-feet, instead
of being simple branchial plates, are foliaceous appen-

ISOPODA. 101

dages that are evidently powerful for swimming purposes.
They are biramous, and consist, as in Amphipoda, of three
pairs; moreover, the form of the body and the large size
and cheliferous condition of the first, or (as in Apseudes)
of the first and second pairs of legs (gnathopoda),
remind us of the Amphipodous rather than of the Iso-
podous type.

By Linneus the animals of this order were arranged
almost entirely under the single genus Oniscus, and from
their flattened oval form they bear a certain general re-
semblance to the Brachyurous Decapods, especially to
such anomalous genera as Remipes and Hippa; whilst
the Amphipods, from their compressed or cylindrical
form, may be considered more especially as the represen-
tives of the Macrourous division. This system of analogy
is also supported by the movements of the animals in
these several groups, the Brachyura and Isopoda being
pre-eminently crawlers ; whilst the Macroura and Am-
phipoda are powerful swimmers, both of the last-named
sets of animals using the tail as the principal organ of
progression. The body of the Isopods is depressed,
generally broad, and of an oval form; in some few
cases it is narrow (as in the Apseudes, Arcturus, and
Anthura) ; in others, Sphzromide and Armadillide, it
is constructed so as to be capable of being rolled up into
a ball, and in a few it is unsymmetrical, as in the females
of certain Bopyride. The texture of the outer integu-
ment is of a firmer consistence than in the Amphipoda ;
although in some of the parasitic species it is soft and
almost fleshy. The head, except in some of the aberrant
families, is distinct from the body, as are the several seg-
ments from each other. In the Anceidz, which possess
only five pairs of legs adapted for walking, the three
posterior segments of the body of the female are more or

102 ISOPODA.

less soldered together. There is considerable difference
in the number of segments composing the tail (pleon),
the terminal piece of which is often of large size; and
there is also considerable diversity in the structure and
functions of the appendages of the tail segments (pleon),
which never form multiarticulated appendages, as we
have seen to be the case with the pleopoda, or tail-feet
of the Amphipoda.

Except in the aberrant families, the head is generally
small, and is never confluent with the following segment.
The eyes are fixed at the sides of the upper surface.
These organs vary considerably in size in the different
groups, occupying nearly the whole upper surface of the
head in the Rocinelz, and being almost obsolete in some
species in which the tegument of the head, over the place
of these organs, appears smooth and transparent, whilst
in other cases the very distinct and large size of the
hexagonal lenses is very marked.

The antenne occupy the anterior part of the head,
and consist of two pairs, generally small, or of but mo-
derate length; sometimes, indeed, the upper pair are
rudimentary, asin many of the Oniscide. They generally
consist of three large basal joints and a multiarticulate
terminal slender filament ; sometimes, however, the latter
part is very much reduced in the number of its articula-
tions, which are enlarged, so as to appear as though regu-
larly continuous with the basal joints. The first pair of
antenne, except in the aberrant genus Apseudes, is never
furnished with a secondary appendage at the base of the
fourth joint, which is so constantly the case in the Am-
phipoda (being either large or rudimentary in the larva
or adult stages, so that it may possibly be a universal
feature of that order).

The parts of the mouth are generally strongly deve-

ISOPODA. , 103

loped, with the mandibles large and horny, the animals
being especially scavengers in their habits. The upper
lip is large and transverse, or somewhat triangular in
form ; the mandibles are generally subtriangular in form,
with a large prominent terminal dentated piece, below
which, in some groups, is a small secondary movable
denticulated appendage; many of the species have this
organ furnished with a three-jointed * palpiform ap-
pendage, or rather (if we adopt the theory of these
mouth-organs being only modified limbs) the basal
horny part of the mandibles is composed of two or
three joints soldered together, whilst the terminal joints
are reproduced in the shape of a palpus, which is, how-
ever, obsolete in certain groups.{ The mandibles are
succeeded by two pairs of maxiliz, which are generally
of a delicate texture, the anterior pair composed of two
terminal subcylindrical curved lobes, with strong spines
at the tips, whilst the posterior pair consist of three deli-
cate membranous plates affixed to a basal stem. ‘There
is, however, considerable difference in the structure of
these organs in the different groups. The pair of foot-
jaws closing the mouth beneath is generally of large size,
the basal portion often defended at each side by a large
triangular plate, whilst the terminal joints form a large
and broad palpus, shutting over the sides of the mouth,
which is, moreover, provided in its inner portion with a
bilobed lower lip of considerable size.

The segments of the body, seven in number, are gene-

* Savigny (Egypte Crust., Pl. 12, fig. 17) represents the mandibular appen-
dage of Spheroma as four-jointed, having mistaken a twist in the second
joint for an articulation.

+ The structure of the mandibles in Maia Squinado, and Nebalia, for ex-
ample, affords strong presumption of the correctness of this view of the sub-
ject, the basal portion, although exarticulate, showing the three divisions of
which it is composed thoroughly soldered together.

104 ISOPODA.

rally nearly equal in size,* movable, and with the pos-
terior lateral angles generally extending backwards over
the base of the legs. The large dorsal are of each seg-
ment is accompanied at each side with a small but distinct
plate (epimeron of M. Milne Edwards), on the under-
side of which the corresponding leg is affixed. These
scale-like pieces, which are the first joints of the legs,
are often soldered to the dorsal arc, their limits being
indicated by impressed lines; but in other cases, as in
Rocinela, AXga, &c., they are very distinct, forming
acute lateral points to the segments. ‘The legs are, for
the most part, of small size, and more or less uniform
in shape: they are (generally) affixed to the lateral
margins of the underside of the body, the basal joint
being long and lying flat on the breast, its extremity
being brought into contact with the extremity of the
basal joint of the opposite leg, whilst the second and fol-
lowing joints of the leg are affixed at an angle and
directed outwards. This arrangement of the limbs is
especially marked in the anterior pairs, which thus put
on the appearance of outer mouth-organs. The legs
generally terminate in hook-shaped fingers, which, espe-
cially in the parasitical species, are of considerable size
and power. In the arrangement of these limbs there
may, however, notwithstanding their general conformity,
be observed somewhat of the division into series which
we have alluded to in our introduction to the Amphipoda
(vol.i. p. 7). Thus in Arcturus the first pair, the second,
third and fourth pairs, and the three posterior pairs, con-
stitute distinct series both in structure and function,
whilst in Serolis and Apseudes the first pair is as greatly

* In Tanais, which in some respects might almost be regarded as the link
between the Isopoda and the Squillids, the first segment of the body is of
large size, and is confluent with the head.

ISOPODA. 105

developed as the corresponding pair of legs of Squilla,
which bears a large pair of sabre-like claws; indeed,
this arrangement of the limbs in Arcturus very satisfac-
torily settles the question of the homologues of the limbs
of Squilla, which has been the subject of some discussion.
In the true Isopoda, however, the three anterior pairs of
legs are directed forwards, and the four posterior pairs
backwards, thus differing from the Amphipoda.

In the female Isopoda the legs are provided at the base
with a series of large membranous plates, arranged so as
to lie in a horizontal position, overlapping one another,
and together forming a pereionic pouch within which the
eggs are lodged during incubation, and the young are re-
tained for some time after they are hatched. The respira-
tory apparatus of these animals being different from that of
the Amphipoda, the vesicular appendages, which exist at
the base of the legs of the latter, serving as branchiz
(vol. i. fig. * 1’”), are not found in the Isopods,* their duty
as organs of breathing being transferred to, and performed
by, the organs attached to the pleopoda (tail-legs), modi-
fied in various ways. The tail (pleon) is always short,
but well developed; the six joints of which it is com-
posed are often more or less fused together ; thus, whilst
in the Ligiidz the six segments are all distinct, in the
Asellide they are almost reduced to one very large
terminal plate. The five anterior pairs of appendages
attached to the underside of these tail segments are em-
ployed as respiratory organs, and consist of a peduncle,
bearing at its extremity two large oval, movable, folia-

* Except, as before remarked in the genus Tanais, and also in the genus
Tone, which Latreille was thence induced to place in the order Amphipoda,
but which Prof. Milne Edwards considered to belong to the Isopoda, allied to
the Cymothoide (Régne An., Ed. Crochard, Crust., pl. 59, fig.1). It appears

to us to be most nearly allied to the Bopyride, especially to the recently
established genera Athelgue and Prosthete.

106 ISOPODA.

ceous plates, membranous in their texture, and arranged
so that one lies upon and protects the other, the inner of
which is generally more delicate than the outer one,
and the two penultimate (s.-¢.) are generally furnished
with true branchiz attached to the posterior surface of
the inner plate. The arrangement of these organs in
the Anceidz is very remarkable, the two pairs of plates
attached to each of the five basal segments being small
and free, as in Squilla, the tail, also, being terminated by
a five-plated apparatus. This peculiarity in the branchial
organs formed the subject of a communication made by
Professor Westwood to the British Association, in the
year 1832 (p. 593).

In the female of the remarkable genus Ione each of
the five basal segments of the tail is furnished with a pair
of long branching very slender filaments, somewhat re-
sembling a piece of coral in miniature; whether these be
employed as respiratory organs has not been observed,
the long filiform appendages attached to the three ante-
rior pairs of legs having been regarded as employed in
breathing. The posterior pair of pleopoda always, how-
ever, differ from the preceding pairs, and either form a
pair of strong valves, shutting together in a straight line
so as to cover and protect the other respiratory plates, as
in Idotea, or are transformed into a pair of double or
single branched crustaceous plates (Sphzroma, &c., Onis-
cus, &c.), forming, with the central apical plate of the
tail, a fan-like appendage of three or five pieces, similar
to that which terminates the body of the macrourous deca-
poda, or these lateral appendages are elongated into long
terminal filaments which sometimes, as in Ligia italica
and Apseudes talpa, equal the entire body in length.

The majority of the Isopoda being aquatic, respira-
tion takes place by means of the pleopoda transformed

ISOPODA. L107

into branchie variously arranged, as above described; but
in the terrestrial species of the Oniscidz a remarkable
modification exists in the structure of these same appen-
dages, to fit them for performing the office of respiration
to animals which would be destroyed if immersed in the
fluid from which the aquatic species are enabled to ob-
tain their necessary supplies of oxygen. Instead, there-
fore, of acting as gills, the two or four anterior pairs of
these organs are transformed into lungs, their interior
being furnished with canals into which the atmospheric air
penetrates by means of orifices answering to the spiracles
of insects, and which, although generally very minute and
numerous, are of large size and very distinct in the genus
Tylos, Latr., inhabiting the shores of the Mediterranean,
for the details of which we are indebted to Savigny’s
beautiful figures in the great work on Egypt. It is,
moreover, worthy of notice, with reference to the corre-
lation of organs, that in these terrestrial species the in-
ternal pair of antenne are so extremely minute as to be
scarcely visible, consisting of a small three-jointed style,
whilst the exterior pair are of large size.

The nervous system of these animals approaches nearly
to that of the true insects, consisting of a double thread
united together at intervals by ganglions, the second and
six following of which send off nerves to the seven pairs
of legs; thus showing that the two anterior pairs,
although homologous with the two outer pairs of mouth-
organs of the Decapods, are really legs in the true sense
of the word. The segments composing the tail receive
the whole of their nerves from the terminal ganglion; a
fact of much significance with reference to the real ho-
mologues of the segmental development of these Crusta-
ceaus. ‘This description is founded on the observations
of M. Cuvier and our own dissections of Ligia; but

108 ISOPODA.

Mr. Dana insists that the Isopods have but a single cord
between the ganglia, whilst it is doubled in the Amphi-
pods, founding thereon an argument of inferiority in the
double-corded Amphipods, the single cord only appearing
in the higher Crustacea, whilst its existence in a double
state indicates a diminution in the nervous influence of
the creatures. He has omitted to state upon what
species he has founded his observations; but Brandt
(Med. Zool., vol. ii. p. 76, Pl. XV., fig. 28) decidedly
figures the nervous system of the Oniscide as consisting
of a double cord; and the same fact has also still more
recently been clearly demonstrated by Franz Leydig in
his excellent ‘* Tafeln z. Vergl. Anat.,” 1864, Pl. VI., f. 7,
representing the nervous system of Porcellio scaber.

According to Edwards and Audouin, there is a gan-
glion to each segment of the pleon.

The male external organs of generation consist of a
pair of linear or filiform appendages or hooks near the
base of the hind legs, or between the base of the anterior
pair of appendages of the pleon, except in Anceus, which
Mr. Hesse has recently demonstrated to be the male of
Praniza, in which the organ is a single median intromit-
tant process.

The young when hatched differ from the perfect ani-
mals in possessing a narrower form, and with the limbs
not fully developed, and in some genera with fewer seg-
ments to the pereion at the period that the larva quits
the egg. During the period of embryonic existence,
according to the observation of Dr. Fritz Miller, the
animal within the ovum is rolled outwards except in the
aberrant Isopoda, which in this resemble the Amphipoda
by being rolled inwards.

The classification of the Isopopa, with reference to the
affinities of the different animals amongst themselves and

ISOPODA. 109

their relations to the other Edriophthalma, is by no
means satisfactory. If the organs of locomotion and
those of manducation and respiration, together with the
relative position of the latter, are regarded as affording
the primary distinctions between the Amphipoda and
Tsopoda, we must regard those Isopods as pre-eminently
typical of the order which possess the greatest uniformity
in the structure of the legs, and which have the breath-
ing apparatus affixed to the underside of the tail instead
of the body, and which are destitute of a palpiform ap-
pendage to their mandibles. The Idoteidz and Onis-
cide fulfil these conditions most completely, the former
agreeing with the great majority of the order in having a
branchial apparatus fitted for the use of aquatic existence,
whilst the Oniscidz differ from all the rest in having the
branchiz transformed into lungs. The Oniscide, more-
over, are terrestrial, or, at least, found in damp situations,
where they breathe the free air, and these can scarcely,
therefore, be regarded as pre-eminently typical of an ex-
tensive series of groups, all the rest of which are aquatic.
The great family of Spheromidz fulfil the greater por-
tion of the conditions of a typical group set down above,
but they have a palpiform appendage to the mandibles ;
on the whole, however, they appear to constitute a well-
marked ovate or globose type of the order, whilst the
Idoteidz have a more elongated general form. We
therefore accept Ligia, holding, as it does, an interme-
diate position between the aquatic and air-breathing
Isopoda, as the most typical genus of this order. All
the remaining tribes are more or less differentiated.

As the British species of Isopoda contain representa-
tives of nearly all the known groups into which the order
has been subdivided, it will be necessary to notice the

110 F ISOPODA.

chief modes of distribution of the groups hitherto pro-
posed.

Latreille, having separated the anomalous genera Jone,
Apseudes, Anceus, and Praniza (which he placed among the
Amphipoda), divided the remainder of the order into six
sections :—

1. EprcaripEs (Genus, Bopyrus) ;

2, CymorHoaDaA (Serolis, Cymothoa, &c.) ;

3. SPHHROMIDES (Spheroma, &c., Anthura) ;

4, Inereres (Idotea, Arcturus) ;

5. AsELLota (Asellus, &c.) ;

6. OntscipEs (Ligia, Oniscus, &c.) ;
thus commencing with the abnormal parasitic species, and
terminating with the terrestrial ones.

Professor Milne Edwards adopted a different principle
of classification, dividing the order into three sections :—

1. Isopopes MARCHEURS, in which the terminal ap-
pendages of the tail are styliform or opercular, and never
formed into swimming appendages, consisting of three
families—Idoteides (Genera, Arcturus, Idotea, and An-
thura). 2. Asellotes (Genera, Apseudes, Tanais, Limnoria,
Asellus, &c.). 3. Cloportes (Genera, Ligia, Oniscus, &c).

2. IsopopES NAGEURS, in which the terminal appen-
dages of the tail form a swimming apparatus, consisting
of three families:—1. Praniziens (Genera, Praniza and
Anceus). 2. Sphzromiens (Genera, Spheroma and Ancinus
(allied to Serolis ?). 3. Cymothoadiens (Genera, Serolis,
Aga, Cirolana, and Cymothoa, &c.).

3. IsopopES SEDENTAIRES, with the mouth more or
less rudimentary (Genera, Bopyrus and Jone).

Here we find the four anomalous genera placed by
Latreille among the Amphipoda referred to the present
order, and Latreille’s general arrangement nearly re-

ISOPODA. 11]

versed. In other respects the groups proposed by M.
Edwards are natural ones, except the Asellotes, which
appear to us unnaturally increased by the introduction
of the genera Apseudes and Tanais.

The classification of these animals by Mr. Dana, who
has bestowed an unusual amount of attention upon the
class Crustacea, demands a more extended notice.

Rejecting the division of the Crustacea into, 1, those
with proper jaws; 2, suctorial species; and 3, those
with the basal joints of the feet acting as jaws,* as pro-
posed by Milne Edwards, on the consideration that too
great a stress has been laid upon the organs of mandu-
cation, Mr. Dana proposes to adopt three primary divi-
sions: 1, Podophthalmia; 2, Edriophthalmia, comprising
the whole of the remainder of the Crustacea proper ;
and 3, the Cirripedia: dividing the Edriophthalmia into,
1, Choristopoda (or Tetradecapoda); 2, ‘Trilobita;
3, Entomostraca ; and 4, Rotifera.

In the revision of the classification of the Crustacea
given in the latter portion of his great work (founded
upon subsequently-acquired views of Cephalization and
consequent concentration or dispersion of forces), Mr.
Dana modified this arrangement of his primary groups,
giving five subclasses, namely—I. Podophthalmia (or
Decapoda, including Mysis and Squilla) ; II. Tetradeca-
poda— Order 1, Choristopoda; Tribe 1, Isopoda; Tribe 2,
Anisopoda; Tribe 3, Amphipoda: Order 2, Trilobita, of
doubtful situation; III. Entomostraca; IV. Cirripedia ;
V. Rotatoria.

Thus his Choristopoda are equivalent to Leach’s Edri-
ophthalma. Here also, rejecting Latreille’s order Lamo-
dipoda, Mr. Dana admits two prominent groups; the

* Mr. Dana (Crustacea, p. 9), by a strange mistake, speaks of the basal
joints of the feet acting as legs instead of jaws.

ke ISOPODA.

Amphipoda, which form the subject of our former
volume, and the Isopoda, in which the tail is short, with
the articulations admitting of little flexion, and with
four or five pairs of abdominal appendages, which are
lamellar and branchial, and only the posterior styliform.
The Isopoda, moreover, are further distinguished by
having only the three anterior pairs of thoracic feet di-
rected forwards (instead of four, as in the Amphipoda),
and four pairs directed backwards.

These two primary groups he, moreover, considers to
be united together by such genera as Tanais, Arcturus,
&e., which he affirms agree with the Amphipoda, in
having the four anterior pairs of legs directed forwards,
and the three posterior pairs backwards; but, like the
Isopods, they have the pleon very short, with only the
last pair of members styliform, the others being lamellar
and branchial, as in the Isopods. ‘These, therefore, he
proposes to form into a third tribe, to be called Aniso-
poda.

As the most recent revision of the animals comprised
in the present volume, it will be useful to give the follow-
ing condensed sketch of his arrangement of the two tribes,
Isopoda and Anisopoda.

Tribe 1, Isopoda.

Subtribe 1, Idotzidea.
Fam. 1, Idotzide.
Fam. 2, Chetilide.
Subtribe 2, Oniscoidea.
Fam. 1, Armadillide.—Subfam. 1, Tyline; sub-
fam. 2, Armadilline.
Fam. 2, Oniscide.—Subfam. 1, Oniscine; sub-
fam. 2, Scyphacine ; subfam. 5, Lygine.
Fam. 3, Asellida.—Subfam. 1, Limnorine; sub-
fam. 2, Asellina.

ISOPODA. 1138

Subtribe 2, Arcturidea (Anisopoda Idotzica),
Fam. 1, Arcturide.—Subfam. 1, Arcturine ; sub-
fam. 2, Anthurinz.
Subtribe 3, Tanaidea (Anisopoda Oniscica).
Fam. 1, Tanaide.—Subfam. 1, Tanaine; sub-
fam. 2, Liriopine ; subfam. 3, Crossurine.
Fam. 2, Bopyride.—Subfam. 1, Bopyrine; sub-
fam. 2, Ionine.

Of the few divisions, the names of which are printed
in italics, no representatives have hitherto been de-
tected in the British Seas. This is the more remarkable
as regards the entire parasitic family, Cy MorHoID&, com-
posed as it is of three subfamilies, Of the remaining
extra British groups, the CH#TILID& is composed of the
single genus Chetilia, Dana, with the sixth pair of legs
exceedingly long and multiarticulate, founded on a Pata-
gonia species ; the TyLIN# is composed of the spiracled-
branchial Tylos, Latreille, from the shores of the Medi-
terranean. The ScyPHACcIN#, consists of the genera
Scyphax, with one species from New Zealand, and Sty-
loniscus, with two species from Terra del Fuego and the
Friendly Islands; the Anctntn&, of doubtful location,
is composed of the genus Ancinus, Edwards; and the
SEROLID&, composed of the flattened genus Serolis, from
the Southern Seas, with strong claws to the fore legs.

Of the subdivisions composing the three subtribes of
Isopoda proper we can speak with satisfaction; but the
whole arrangement of the Anisopoda seems to us un-
natural: thus, referring only to the British groups, we
consider, Ist, that an arrangement which can group
together the female of Anceus (Praniza) and Serolis
must be founded upon entirely false principles. 2ndly,
that Arcturus, although exhibiting a remarkable modifi-
cation in its legs and basal segments of its tail, possesses

VOL. Il. I

114 ISOPODA.

so strong a relationship to Idotea, through its opercular
breathing apparatus, that it ought not to be far removed
from it. So, also, Anthura, although the structure of the
breathing apparatus of the tail appendages is very pecu-
liar, possesses in its elongated form and nearly uniform
feet only a relation of analogy with Arcturus, its relation
with Tanais having been hitherto mistaken. Srdly, the
Liriopine are more properly referable to the Bopyride.
Athly, the Crossurine are synonymous with Tanais, the
genus Crossurus (Rathke), on which Dana has founded the
subfamily, being a true Tanais. And 5thly, the Bopyrine
are strictly Isopods so far as the legs are concerned ;
the structure of the mouth, parasitic habits, and remark-
ably degraded condition of the female sex, constituting
them into a solitary group far removed from the other
Isopods, and analogous to the Hyperiidea among the
Amphipoda. With these prefatory remarks we beg
to propose the following tabular arrangement of the
Order, in which we have availed ourselves of the most
important peculiarities of each mode of classification
alluded to above. We consider, on the one hand, that
Tanais, by the presence of branchial vesicles attached to
the body, approaches nearest to the Amphipoda, and,
on the other hand, that Oniscus, from the presence
of internal spiracles, as has been recently shown by
Waener,* comes nearest to the Insecta, and, conse-
quently, these two genera form the extreme limits of the
order.

* Ann. Sci. Nat. tom. iv. p. 323, 1865.

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116 ISOPODA.

Group—A BERRANTIA.

Tuts group is formed of those crustacea which, al-
though belonging in certain important conditions to the
order Isopoda, offer peculiar aberrant characters.

In the Amphipoda the branchial organs are (as in
the Podophthalmic orders) attached to the appendages
of the body. In the aquatic Isopoda they are attached
to the fourth and fifth pairs of the appendages of the
tail. But in the several genera which we link together
to form this group, the branchial organs have not been
made out; indeed, both Dr. Fritz Miller and Prof.
Lilljeborg assert that no such organs exist.

In one genus alone (and possibly only in certain
individuals of that genus) we have detected a saccular
appendage attached to the coxa of the third pair of
pereiopoda (or fifth pair of legs), that can, we think,
only be interpreted as a branchial organ similar to those
which exist in the Amphipoda attached to most of the
legs. Again, in Amphipoda, the heart les beneath the
dorsal surface of the body, in the Isopoda in the tail.
In Tanais and Apseudes, according to Dr. Fritz Miller,
the heart is situated as in the Amphipoda. And in the
embryonic condition the development is after the manner
of the Amphipoda rather than that of the Isopoda.

We restrict this group to the typical genera of Dana’s
sub-order Anisopoda. It also corresponds with Dr.
Milne Edwards’ AssELOTES HETEROPODES, to which we
have added the family of ANTHURIDZ.

This group, in consequence of the variation in habits,
we have divided into two tribes, VAGANTIA and SuB-
PARASITICA.

TANAIDA, 117

Tribe—VAGANTIA.

THE non-parasitic aberrant crustacea are distinguished
from the sub-parasitic ones not only by their different
condition of life but also by their having fully developed
enathopoda (and consequently possessing seven pairs of
legs), of which, at least, the anterior pair is of a large
size and more or less cheliferous.

They form two families, Tanaide and Anthuride.

Fam.—TANAIDZ.

THE body in these Isopods is long and narrow.
The head is confluent with the first segment of the
body, the eyes are more or less distinctly placed on
footstalks. The antenne vary in length. The first
pair of gnathopoda, or the anterior pair of legs, are
of large size and cheliferous, or terminated by a didac-
tyle claw ; the second pair are of an intermediate form,
but approximating more nearly to that of the pereiopoda
than to that of the first pair. The eggs are borne
in a sub-pectoral pouch beneath the five central segments
of the body. The tail is terminated by two setaceous
articulated appendages.

The family corresponds with Professor Milne Edwards’
tribe of Asellotes hétéropodes—the Asellota heteropa of
Latreille’s Familles naturelles. It comprises the genera
Apseudes (Rhea), Tanais, Paratanais, and Leptochelia.

The last-named exotic genus is especially interesting

118 TANAIDA.

from the length of the antennz (nearly equal to that of
the entire body), and to the greatly elongated anterior
pair of legs (nearly twice that of the antenne). It
is founded upon a minute species from the Feejee
Islands, and was observed by Mr. Dana to be caprelloid
in its habits, attaching itself by its hinder legs to sea-
weeds, and reaching out the long arms in different
directions as if in search of prey. In other respects
the genus is closely allied to Tanais, T. Edwardsii of
Kroyer, Tidssk. iv., 1842, pl. 2, figs. 13-19, being con-
sidered by Dana to belong to the same genus. This
is, however, doubtful, since, according to Fritz Miiller,
that species is the male of JT. Savignyi,-and it is not
improbable that the female of Leptochelia may also
prove to be a true Tunais, in which genus it has, indeed,
been placed by Lilljeborg in his recent memoir on this

family.

TANAIS. 119

ISOPODA, TANAIDZ,
VAGANTIA.
Genus—TANAIS. (Andouin and Milne Edwards.*)
Zeuxo. TrmPLeron, Trans. Ent. Soc. ii. (1836).
Crossurus. RatHKeE, Noy. Acta. xx.

Anisochetrus. Wurstwoop, Ann. Se. Nat. xxvii. (1832).

Generic character. Body elongated. Cephalon and first seg-
ment of pereion confluent. Antenne short, subequal. First
pair of gnathopoda very large, didactyle ; second pair slender,
simple, and assimilating to the pereiopoda. Pleon five-jointed,
fourth joint short, fifth terminated by a pair of single-branched
filamentary uropoda.

In the large size of the first pair of didactyle legs,
and in the confluence of the head and first segments
of the body, this genus agrees with Apseudes, but the
second pair of legs are slender and simple, and the
tail is terminated by two short slender appendages com-
posed of but very few articuli. The antenne are also
short, being nearly equal in length, although the inner
or superior pair are much stronger than the outer pair.

The body is small and has the sides nearly parallel.
The head and first segment of the body are so closely
soldered together that little or no trace of their separa-
tion is visible from above; the anterior portion of the
head is produced into a point. The eyes are porrected
on short footstalks, which are movable in the males,
according to Fritz Miiller, but which, according to Van
Beneden, are completely immovable. The upper or
inner antenne are seldom so long as the head and fol-
lowing segment; they are straight, directed forwards and
downwards, and are much thicker than the lower pair ;
they are formed of a peduncle which consists of three

* Résume (not Précis) d. Ent. p. 182 (without description—1829), pl.
xxix. fig. ], ‘* Tanais de Costa,” not ‘‘Tan. Cavolini.” (The reference by
M. Edwards to Ann. Sci. Nat. xiii. 288, is erroneous, being intended for
Rhea.) Latr. Cours d’Ent. 403,

120 TANAIS.

cylindrical joints and a rudimentary flagellum, which is,
however, considerably elongated in some species, as in
T. Edwardsii, where it is seven-jointed; according, how-
ever, to Fritz Miller, the sexes differ in the structure
of their antenne. A small auditory cavity exists in
the first joint of the peduncle. ‘These antenne are
attenuated to the tip, which is furnished with a strong
pencil of hairs. The lower antennz resemble the upper
in direction and length, but they are more slender, and
consist of a five-jointed peduncle, of which the first
and third are short and ring-like, and the fifth is also
terminated by a few hairs, within which is also a rudi-
mentary flagellum. The mouth is well formed for biting.
The upper lip is conical, resembling that of the Gammari,
with a ridge along the medium line terminating in a
produced point. The lower lip is formed of two ovate
pieces fixed obliquely, united together at their extremity,
leaving a triangular space between them, arising from
a reversed triangular piece rounded at its base.* The
mandibles are horny and elongate-triangular, terminated
in a denticulated point rather incurved, with a deep
impression and a moyable denticulated tooth fixed be-
neath the apex; towards the base on the inner edge, is
a strong somewhat squared molar tooth, truncated, and
having the entire edge of the truncated part notched
for chewing: in the middle of the outer edge is a small
tubercle emitting a short bristle, probably representing
the mandibular palpus. The inner pair of maxille
are strong, formed of a long, curved, sub-cylindrical
outer portion, with the apex truncate and spinose, and
a biarticulated inner division with the tip of the second

* We believe this piece, represented by Savigny as described above (and
more nearly agreeing with the figure of the same organ in Gammarus than in
Cymothoa), is identical with the piece described under the name of Under-
leben by Kroyer (Tidssk. iv. 170).

TANAIS. 121

joint armed with strong seta; these two divisions are
fixed upon an oblong movable basal joint. The outer
pair of maxille, according to Savigny, consists of a
pair of organs, each of which is formed of three slender
oval plates lying upon each other and arising from an
oblong basal joint.

The pair of foot-jaws (g), closing the mouth from
beneath, is of large size, brought into contact with each
other along the inner edge of the basal half, the first
joint being nearly square, but with the base produced at
the inner angle; the second joint is short, but swollen on
the outer edge and produced within into a flat oval plate,
ciliated along the margin; the third and fourth joints
respectively are nearly triangular in form, with a strong
pencil of hairs on the inner margin; and the terminal
joint is slender, curved, and affixed at the apex of the
preceding joint so as to rest upon its inner edge, the
top and inner margin being also furnished with a long
pencil of hairs. The organs of the mouth occupy nearly
the whole of the under-side of the conjoined head and
first segment of the body, leaving the laterally-dilated
posterior angles for the insertion, on the under-side,
of the base of the large first pair of legs.

The first pair of legs are not only evidently very
powerful organs of prehension, but are also employed
by the animal for the defence of the parts of the mouth,
upon which, when unemployed, they fold very closely.
They are of large size and very robust, with the wrist
oblong, and the hand large and sub-ovate, set on the wrist
obliquely, having the infero-anterior angle produced into
a strong fixed finger, against which the movable apical
finger works, forming a powerful didactyle claw. The
second pair of legs are more slender than the remainder,
and somewhat longer than the third pair; the segment of

122 TANAIS.

the body, also, to which they are attached, is shorter
than the remainder. They are simple in their structure,
and terminated by a long, slender finger. The five re-
maining pairs of legs are also simple, and gradually but
slightly thickened from the third to the seventh pair,
which is the thickest. The slender membranous plates
forming the incubatory pouch in the female are attached
to the base of several of the intermediate pairs of legs,
Fritz Miller, in his remarkable work “ Fir Darwin”
(Svo. Leipzig, 1864, p. 11), gives a lateral view of Tanais
dubius of Kroyer, with the second, third, fourth, and
fifth pairs of legs respectively furnished at the base
with a small oval plate, which he describes as_ the
‘** Anlagen der blatter die spiter die Bruthohle bilden.”

LEG OF TANAIS.

We here give a figure of the fifth leg of Tanais vittatus,
from the coast of Devonshire, having an appendage
at its base, which we regard as a branchial sac similar
to those existing in the Amphipoda, and consequently
affording a proof of the nearer relationship of Tunais
with that order than is possessed by any other isopodous
animal, This appendage is wanting in some specimens,
and its variable existence is probably a character of
specific distinction in the group. Moreover, as we have
found it in the largest-sized specimens, we apprehend
it cannot be regarded as the rudiment of the plates
that form the incubatory pouch, as Dr. F. Miller con-
siders those of 7. dubius to be.

TANAIS. 123

The tail in this genus consists of less than the normal
number of segments, and carries only three pairs of
pleopoda and a pair of terminal uropoda. The segments
may vary in development and distinctness, being more or
less fused together, in the different species. In one
or more species (constituting the genus Crossurus of
Rathke) two of the segments are furnished on the
upper surface with transverse fascicles of long hairs,
and on the under-side with two pairs of delicate oval
membranous plates, strongly ciliated, supposed by
Edwards to constitute the breathing apparatus, but into
which F. Miller affirms not a single blood corpuscle
ever enters. Hach pair of these plates is fixed upon
a common base, and is laid transversely when at rest,
thus differing from the general arrangement of these
organs.

The terminal segment of the body is furnished at
the sides with a pair of short, slender, articulated, fila-
mentary appendages, consisting, in 7. Savignyt and T.
Edwardsvi, of a strong basal joint followed by a six or
seven jointed flagellum, at the base of which is affixed
a minute oval appendage setigerous at its tip. In the
species which we have figured this appendage consists
of only three or four distinct joints.

As yet we are but imperfectly acquainted with the cha-
racteristics of the species as well as with the distinction
of the sexes, habits, &c. The typical species (Gammarus
Dulongu, Andouin) was from Egypt, and is beautifully
illustrated by Savigny in the great work on that country.
In Kroéyer’s monograph of the genus, published in the
fourth volume of the ‘* Naturhistorisk Tidsskrift,” seven
species are described, namely, 7. Edwards and Savignyt
from Madeira, 7. dubius from Bahia, in Brazil, 7. gracilis
from Spitzbergen, J’. tomentosus from the Norwegian
Sea, and 7. Orstedii and T. Curculio from Oresund. The

124: TANAIS,

last four species are described in detail in the second
series of the same work (vol. ii. p. 408).

In a paper on the structure and relations of the genus
by Fritz Miller (Archiv. f. Naturg. 1864, p. 1—) the
author is, however, induced to consider that 7. Edwardsii
and Savignyt are the sexes of the same species, and
that 7. curculio and Orstedii ave in the same condition.

From the various localities in which the different
species have been found, we presume that they were
taken at large by dredging, and consequently are not
parasitic in their habits. Van Beneden, however (who
has published some observations on the genus in the
fifth volume of the second series of the * Bulletin of the
Académie Royale de Belgique,’’ as also in his “ Re-
cherches sur la faune littorale de Belgique,” Crust. p. 93,
pl. 164, where he has given a rude figure and details of
T. Dulongi), states that he obtained a male and five
females of that species from the carapace of a Chelonia
mydas, thrown upon the shore near Ostend, which would
indicate a carnivorous condition of life for that species.

Ina memoir on the relation which this genus holds
to the order of Isopoda,* Prof. Lilljeborg unites in
this genus not only Crossurus of Rathke, but also Para-
tanais and Leptochelia of Dana. By so doing he finds
himself compelled to commence by separating that
division of the genus which carry two branches to the
posterior pair of pleopoda from those that carry but
one. We think that it is more convenient, in our present
state of knowledge, to keep apart as much as possible
animals possessing a marked structural distinction. We
therefore retain in this work Dana’s genus of Para-
TANAIS.

* Bidrag till Kainnedomen om de inom Sverige och Norrige fére Kom-
mande crustaceer af Isopodernas underordning och Tanaidernas familj.
Af Wilhelm Lilljeborg. Upsala 1864.

TANAIS VITTATUS. 125

ISOPODA. TANAID.
A BERRANTLA.

TANAIS VITTATUS.

Specific character. Body rather short, with the segments of the pleon
clothed with transverse fascicles of long fine hairs. Superior antennze
thicker and longer than the inferior, three-jointed, setose at the tip. Ce-
phalon and first segment of the pereion mottled with dark lines, forming oval
patches; second pair of gnathopoda shorter than the following, several of
the posterior pairs of legs terminated by a sickle-shaped finger, with a tooth at
the middle of its inner edge, and serrated along the base.

Length two lines and a quarter.

Crossurus vittatus. RatuKen, Nov. Act. 20, pl. i. fig. 7.

Tanais vittatus.. Litusezore, Bidrag till Kinnedomen om de inom
Sverige och Norrige Férekommande crust. af Isop.
underord. och Tanaid. famil. p. 24. 1864, Upsala.

Tanais de Costa (?). Anpovurn and Epwarps, Résumé d’Entomologie, t. i.
jue Seebe, Tee 1G

Tanais Cavolini (?). Epwarps, Hist. Nat. Crust. iii, p. 141, pl. xxxi.
fig. 6.

NotwitusTanpine the Gulf of Naples is given by
Professor Milne Edwards as the habitat of 7. Cavolinii,

126 TANAIS.

we have but little hesitation in referring to it the
specimens from the South Coast of England, Berwick
Bay, and Glasgow, agreeing as they do with a specimen
in the Hope Collection at Oxford, bearing the label
of that name in the handwriting of, and most probably
collected by, Signor Costa, in the Bay of Naples.*
There are, however, several characters in which our
specimens agree so closely with those described below
under the name of Paratanais Dulongii, that we
should not be surprised if it should be ascertained
that (notwithstanding the remarkable clothing of the
basal segments of the tail) these individuals should
prove to be the females of the former. We were
at first, indeed, disposed to regard these specimens as
being the T. tomentosus of Kréyer, from the Norwe-
gian Sea, but that species is described as having ‘‘ omnes
fere corporis partes pilis longissimis crispis obsite,”
which is certainly not the case with our specimens.
It must, however, be observed that some of our speci-
mens of Jarge size are entirely destitute not only of
the ventral scales forming the incubatory pouch, repre-
sented by Rathke and Miller, but also of the appen-
dages alluded to above as representing the branchize
according to Mr. Spence Bate.

The general proportions of the animal agree with those
of T. Dulongii, except that the body is comparatively
somewhat more robust. The head is broader than in
T. Dulongii. ‘The relative size of the two pairs of an-
tennze are shown in the above woodcut, the upper pair
having a slight rudimental flagellum concealed among

* Tn his description Prof. M. Edwards describes the three first segments
of the abdomen as ‘‘tres poilus lateralement,” but the rudeness of his
figure leads us to infer that the hairs extend to the dorsal surface of those
segments.

TANAIS VITTATUS. 127

the base of the terminal sete. The lower antennz are
shorter and more slender than the upper, apparently
four-jointed, the second joint being short, the three
others of nearly equal length, but gradually becoming
more attenuated towards the tip. The foot-jaws resemble
those of T. Dulongi (in our figure the dilated inner
plate of the second joint is omitted, having been lost in
dissection). The fore legs are very large, strong, smooth,
and polished, the hand produced at its lower angle into
a strong immovable finger, having a very small obtuse
tubercle near its base and another beyond the middle,
the intervening space being filled up by a thin portion
of the edge. Several of the terminal pairs of legs are
furnished with a strong sickle-shaped finger, having a
tooth at a little distance beyond the middle of the inner
edge, the space between it and the base being denticu-
lated. In the individuals which we have examined the
under-side of the body is not furnished with the incu-
batory pouch, nor with the short appendages observed
at the inner base of one or more pairs of the legs. In
others, however, as represented by Rathke, the bilobed
incubatory pouch is of large size, occupies the under
surface of the intermediate segments of the body, and
consists of very transparent membranes, allowing the
eggs to be distinctly perceived from beneath; its posi-
tion and appearance indicated in our woodcut being
copied from Rathke’s figure. The most striking cha-
racter of the species, however, consists in the very dense
pencils or fascicles of long thin hairs with which the
upper surface of the second and third segments of the
tail are clothed, and which are set on at right angles to
the body. The terminal segment of the tail is slightly
notched in the middle of the under surface of its pos-
terior margin, and is furnished at its sides with a pair

128 TANAIS.

of short triarticulated filaments, resembling the superior
antennz in structure, and possibly performing similar
functions.

We have received specimens of this species from Ber-
wick Bay, captured by our late friend Dr. George
Johnston, also from Mr. David Robertson, of Glasgow ;
as well as a considerable number of individuals captured
by Mr. Loughrin, at Polperro, who informs us that they
live gregariously below high-water mark, where they
protect their small colony by retiring deeply within the
fissures of the slaty rocks of the coast, where they collect
together a mass of material of a ‘* leathery consistence,”
behind or within which they take shelter. When dis-
turbed they escape, and will spring to a considerable
distance. This is probably done by bringing the head
and tail together and suddenly straightening themselves.

Among the several specimens sent to us by Mr. Ro-
bertson, was one of a very slender form; so peculiar
was it that we figured it under the impression that it was
of a separate species from the present, and named it in
the dredging list as 7. hirticaudatus.* But among the
hundreds that we have had the opportunity of examining
from several localities, we could identify many that
were intermediate between the two extremes, and con-
sider it not improbable that the slender form is but a
specimen that had recently cast its skin.

* Brit. Assoc, Rep. 1860, p. 225.

TANAIS DULONGII. 129

ISOPODA, TANAID,
ABERRANTIA.

TANAIS DULONGII.

Specific character. Body smooth. Pleon destitute of fascicles of hairs.
Antenne subequal in length, the upper pair much thicker than the inferior.
First pair of gnathopoda very robust ; second pair slender, and rather longer
than the pereiopoda. Third pair of pereiopoda with an appendage at the
base within: tail short, obtuse, terminal appendages short, three-jointed.

Length not quite a 4 of an inch,

Gammarus Dulongii(?) | Anpoury, Explicat. Pl. Egypte, t. xi. fig. 1.*

Tanais Dulongit (?) MityE Epwarps, Crust. iii. p. 142. W.THome-
son, in Ann. Nat. Hist. xx. p. 245. Wuurr,
Cat. Brit. Crust. p. 68? Pop. Hist. Brit.
Crust. p. 227 ?

Anisocheirus Dulongii (?) Wuxstwoop, Annales Sci. Nat. xxvii. p. 330.

Tue type of this species, originally figured by Savigny,
was a native of the coast of Egypt; it is, therefore,
with some doubt that we affirm its identity with speci-

* Our outline figures P and v are copied from Savigny’s plate.
VOL. II. K

130 TANAIDA.

mens from the coast of Devonshire which have served
for our work, although the general resemblance is so
great that we prefer to consider them as belonging to
that rather than to any of the species described by
Kroyer. The species has indeed been recorded, without
any expression of doubt, as a native of the Irish coast
by the late W. Thompson, Esq., but the specimens
which were so regarded by him prove on examination to
be mutilated specimens of an amphipodous crustacean.
Some differences, however, exist between our specimens
and Savigny’s figures of the terminal portion of the body,
which we are inclined to regard as arising from inac-
curate drawing on the part of Savigny rather than as
really existing.

The body is of moderate length, smooth, and desti-
tute of hairs, especially on the segments of the tail.
The upper antennee are strong, porrected, and nearly as
long as the large following segment; they are composed
of three joints, of which the basal is the largest and
terminated by a pencil of hairs. The lower antenne
(represented too highly magnified in figure ¢) are rather
shorter and more slender than the upper pair, and five-
jointed, having a very short basal and a short third joint,
the fifth joint terminating in a few hairs. The large
first pair of legs are terminated by a didactyle claw, of
which the immovable finger is strong and truncated
along its inner edge, which is slightly denticulated,
whilst the terminal movable finger is slightly serrated
along its inner edge. The second pair of legs are rather
longer and more slender than the third pair, the five
remaining pairs being nearly equal in size. The second
pair of legs are gradually attenuated to the tip, the finger
being slender, acute at the tip, and but slightly bent.
In the third pair the terminal joints are wider; the fifth

TANAIS DULONGII, 131

pair are furnished at the base on the inside with a small
movable appendage, which we consider as being the
homologe of the branchial organ of the amphipodous
crustacea; the two hinder pairs are more robust, and
better fitted for prehension, with the fingers strong
and hooked. The tail is short, scarcely longer than
wide, and terminated by two short slender three-jointed
filaments.

The only individuals which we have seen of this
species were sent to us from Polperro by Mr. Loughrin.

ISLE OF PORTLAND, FROM THE NOTHE, WEYMOUTH.

132 TANAIDA,

ISOPODA. TANAID.
ABERRANTIA.

Genus—LEPTOCHELIA.

Leptochelia. Dana, U.S. Explor. Exped. p. 800.

Tanais, pars. (Kroyer, Nat. Tidssk. vol. iv. LitsEzore, Bidrag till Kiin-
nedomen om de inom Sverige och Norrige forekommande
Crust. af Isopod. underord. och Tanaid. fam. p, 25.

Generic character. Animal long and slender. First segment
of pereion fused with cephalon, the following six segments sub-
equal. Pleon consisting of six separate segments. Eyes pe-
dunculated. Superior antennz long, and terminating in an
articulated flagellum. Inferior antenne very short. First pair
of gnathopoda long and chelate ; “ fingers slender and gaping”
(Dana); second pair slender, feeble, and terminating in a long
styliform dactylos. The five pairs of pereiopoda subequal in
length, the three posterior pairs having the bases somewhat
more robust than the two anterior pairs. Pleopoda, five an-
terior pairs, biramose; posterior pair unibranched and multi-
articulate.

Tuts interesting genus holds an intermediate position
between TJanais and Paratanais. It agrees with the
former in the general contour of the body, and with the
latter in the form of the second pair of gnathopoda as
well as of the pereiopoda. The pleon has five distinct
segments, each carrying a pair of pleopoda, as in Para-
tanais, but it has only a single branch to the caudal pair
of pleopoda attached to the sixth segment. The an-
tennee are somewhat abnormal, since there is no distin-
guishable peduncle. The superior pair have the first
joint long and robust, the second not half as long as the
preceding, the third and every successive joint is still
shorter than the preceding, so that unless the first two
joints of the peduncle be fused together, it is difficult to

LEPTOCHELIA. 133

determine the limits of that portion of the peduncle.*
In the inferior pair the difficulty is still greater, for
there are but five joints, the last being very rudi-
mentary. In this respect this pair resembles that of the
genus Tanais. The first pair of gnathopoda are very
long, as long as (or much longer than) the superior pair
of antenne. In both the species known, they have a
large gaping chela, which Mr. Dana considers as a
generic distinction, but which we think is very liable to
specific variation.

The only species hitherto referred to this genus is
Leptochelia minuta, found among sea-weed and small
corals in the Island of Ovalan, one of the Feejee group,
the length of which is only one-tenth of an inch.

* Tn the typical species described by Dana, the first joint is a very minute
basal one, and the second very long.

134 TANAIDA.

ISOPODA., TANAIDA,
ABERRANTIA.

LEPTOCHELIA EDWARDSII.

Specific character. Superior antenne half the length of the animal ;
inferior antenne not so long as the basal joint of the superior. First pair of
gnathopoda long, robust, with gaping chela, having the infero-digital process
armed with two strong blunt teeth. Posterior pair of pleopoda short, being
less than half the length of the pleon.

Length } inch.

Tanais Edwardsii. Knriéyer, Naturh. Tidsskr. iv. 181, pl. ii. figs. 13-19.
Dana, U.S. Expl. Exped. p. 800.

Tue animal is slender and linear. The head is fused
with the first segment of the body, the six following seg-
ments subequal, the anterior being somewhat the smallest.
The tail consists of six segments, of which the last is
rather the longest and terminates in an obtuse apex.
The eyes are small, round, consisting of six or seven
rather large lenses, and planted on a small peduncle
placed in front of the anterior margin of the cephalon,
which, however, partly covers it. The superior pair of

LEPTOCHELIA EDWARDSII, 135

antennz are about half the length of the animal, and
consist of one long basal joint exceeding one-third of the
whole length of the organ; the second is scarcely half the
length of the first, and is followed by a series of eight
small joints, each succeeding one being shorter than the
preceding. These eight small articuli are furnished on
the under side with bundles of those membranous hairs
which we have generally considered as being connected
with the acoustic apparatus, and therefore named auditory
cilia, but which Dr. V. Herisen, who has given much
attention to the subject, considers as having nothing to
do with the sense of hearing. The two basal joints of
this organ have not these appendages, hence we think
that they alone represent the three joints of the normal
peduncle. The inferior pair of antennz are very short,
reaching but little beyond half the length of the basal
joint of the superior pair. They are small, slender, and
feeble organs, generally directed obliquely downwards,
and consist of five joints, the first two of which are
robust and short, the two succeeding long and slender ;
the apical one minute and rudimentary. They are fur-
nished with a few long slender hairs. The first pair
of gnathopoda are large, strong, very long, being about
two-thirds the length of the entire animal, and reaching
beyond the extremity of the antennz; the three basal
joints appear to be without the power of articulation,
which exists most freely between the meros and the
carpus; the carpus reaches quite to the extremity of
the basal joint of the superior antennz; the propodos is
longer than the carpus, and with the dactylos forms a
large, gaping, pincer-like claw; the infero-digital process
of the hand is curved, and armed with two strong tuber-
cular teeth; the dactylos is also curved and feebly
serrated, a minute hair springing from the anterior

136 TANAIDA,

surface of every denticle. The second pair of gna-
thopoda are but half the length of the first, being
slender, very feeble, and terminating in a slightly curved
styliform dactylos. The first two pairs of pereiopoda are
formed nearly like the second pair of gnathopoda, but
have shorter, therefore stronger, dactyla. The three
posterior pairs of pereiopoda are reversed from the
preceding in their mode of attachment, and have the
basal joimt more robust than that of the preceding pairs
of pereiopoda; in other respects they resemble them in
form. ‘The five anterior pairs of pleopoda are alike in
size and shape; they consist of a stout peduncle on each
side, and carry a pair of oval, membranous plates,
ciliated with long and strong hairs upon the outer and
inferior margins. The inner plate, if we may judge
from observation after death, is carried at right angles
with the outer, which rests pendant in the water. The
posterior or caudal pair of pleopoda consist of a single
multiarticulate branch, of which the basal joint is larger
than the terminal ones: it consists of nine or ten small
articuli.

We are indebted for this interesting addition to our
British Fauna to the zeal and research of the Rev.
A. M. Norman, who took it during the summer of 1865
among Zostere between tide marks in Belgrave Bay,
Guernsey.

The distinction between this and Dana’s Feejeean
species exists in the latter having longer superior an-
tennez, as also more slender and longer gnathopoda,
which are only armed with a small rudimentary tooth on
the inner surface near the extremity of the fixed finger
of the great claw; the posterior pair of pleopoda are
also longer, being described by the author as equal to
the pleon in length.

PARATANAIS. 1a7

ISOPODA. TANAID&.
ABERRANTIA.

Genus—PARATANAIS. (Dana.)

‘* Like Tanais in having the anterior feet stout and short, and the antenne
without a flagellum, Caudal stylets two-branched, branches unequal, one or
many jointed.”’

Dana, U.S. Explor. Exp. p. 798.

THE above is Dana’s short description of this genus,
which, being founded on a specimen taken in the Sooloo
Archipelago, we have only an opportunity of knowing
through the author’s description.

There are some important points in which our British
specimens differ from the above description, but they
appear to be rather omissions than structural differences.

We therefore give our own character of the genus
founded on British specimens.

The cephalon is fused with the first segment of the
pereion. The eyes are pedunculated. The antennz have
rudimentary flagella; the inferior pair is more slender
than the superior. The first pair of gnathopoda are
robust and chelate; the second feeble and monodactyle.
The pereiopoda subequal in height and resembling each
other in form. Pleon having six distinct segments
supporting six pair of pleopoda, five being double
ovate plates with ciliated margins adapted for swimming,
the sixth forming a pair of biramose substyliform ter-
minal uropoda.

138 TANAIDA.

ISOPODA. TANAIDA.
ABERRANTIA.

PARATANAIS FORCIPATUS.

Specific character.—Body moderately long and slender. Pleon much longer
than broad. Legs short. First pair of gnathopoda serrated along the inner
margin of the digital process of the propodos; second pair of gnathopoda
resembling, but longer than, the pereiopoda. Upper antenne much thicker
and longer than the lower pair. ‘Tail terminated by a pair of short, double-
branched, two-jointed filaments, setose at the tip.

Length one line and a half.

Tanais forcipatus. Linisesore, Bidrag Isop. Tanaid. fam. p. 25.

Tanais Savignyi. Gossr, Mar. Zool. i. fig. 246 (but not of Kréyrr,
Nat. Hist. Tidssk. iv. pp. 168, 181, pl. xi. fig.
1—12).

Zeuxo Westwoodiana? TumpiEeron, Trans. Ent. Soc. Lond, ii. 203, pl. xviii.

THE eyes are planted on peduncles and terminate in
an obtusely pointed apex. The inferior antennz are
shorter and more slender than the superior, but scarcely
so much as represented in our figure.

The first gnathopoda, or chelate appendages, have the
hand armed with three or four small serratures or sharp-
pointed denticles, situated on the distal half of the inner
margin of the digital process of the propodos. The
second has the hand long and slender, the finger forming

PARATANAIS FORCIPATUS. 139

an exceedingly long, delicate, tapering, hair-like point.
The third and fourth pairs of appendages somewhat
resemble the second, but the fingers, though fine and
sharp, are are not so long and hair-like. The three
posterior pairs of legs are reversed, and have their
dactyla short and curved. The posterior pair of pleo-
poda are biramose, both branches being nearly of the
same length, and both two-jointed.

The more elongated form of the body, and especially
of the tail, the short legs, and the short, double-branched,
two-jointed appendages of the tail, distinguish this
species from its congeners. Its small size would, how-
ever, seem to indicate an animal not yet arrived at full
size, and which, when fully grown, might probably
afford less evident distinctive characters. It is proper to
observe, however, that the Tanais Savignyi of Kroyer is
furnished with a pair of seven-jointed filaments at the
sides of the tail, the basal joint being much thicker than
the rest, and furnished at its inner extremity with a short
ovate appendage, setose at the tip, about half the size of
the second joint. We were at the first inclined to con-
sider, from its elongated form, that it was identical with
Zeuxo Westwoodiana of 'Templeton, but not only is that
species represented as having a six-jointed pair of anal
filaments, but the antenne are nearly equal in length.
In other respects the species seem identical.*

The upper antenne are considerably thicker and some-
what longer than the lower, and composed of three
joints gradually diminishing in thickness to the tip, the
first being as long as the two others united, and the

* Since the above woodcut was prepared, we have received from the Rev.
A. M. Norman a specimen, captured among Zostere between tide marks in
Belgrave Bay, Guernsey, which has a pair of six-jointed anal filaments with a
short one-jointed secondary filament arising from the extremity of the basal
joint. Can this be the female of Leptochelia Edwardsi fully grown?

140 TANAIDA.

extremities of all the joints furnished with a few hairs.
The lower antennez are four (? five) jointed and slender.
The second pair of legs are slender, and longer than the
following pair, with the terminal finger long, very
slender, and slightly bent. The third and fourth pair of
legs are very short, and the three posterior pairs longer
and stronger. The tail nearly occupies one-third of the
whole length of the animal, the six segments of which it
is composed being distinct; the five basal ones trans-
verse, and the terminal one rounded at the extremity,
which is furnished with a pair of biramose biarticulated
filiform appendages, slightly hairy at the extremity of
the joints.

The first specimen of this species that we obtained
we dredged in Plymouth Sound. It was very small, and
possessed but six segments to the pereion, and conse-
quently wanted one pair of legs. We therefore as-
sumed it to have been that of a very young animal.
We have since, from our valued correspondent Mr.
Edward, of Banff, obtained two others of larger size,
and with the normal complement of limbs, all the other
features being persistent, a circumstance that induces us
to believe that our description represents the character of
an adult animal.

We are compelled to adopt this conclusion, from its
difference from Tanais, its nearest ally, both in the form
of the second pair of gnathopoda, the number of
pleopoda developed as swimming appendages, and the
biramose condition of the posterior pair of pleopoda.

PARATANAIS RIGIDUS, 141

ISOPODA. TANAID&.
ABERRANTIA.

PARATANAIS RIGIDUS.

Specific character.—Body narrow. Margins of the pereion and pleon
parallel, pleon terminating in a central point. Antenne not longer than the
cephalon. Posterior pleopoda having both rami uniarticulate, the outer
being half the length of the inner.

Length th of an inch.

Tue form of this species is slender and cylindrical,
the sides running parallel with each other from the outer
angle of the anterior margin of the head almost to the
posterior pair of pleopoda. The cephalon is confluent
with the first segment of the pereion, and both together
form a segment that is scarcely longer than broad. The
second segment of the pereion is very short; the third is
about three times as long as the second, and both together
about as long as the cephalon; the fourth segment is
quadrate, and as long as the two preceding ; the fifth is a

142 TANAIDZ.

little longer than the fourth, but about the same length
as the sixth, while the seventh is about half the length
of the sixth.

The pleon has the first five segments subequal, but the
sixth or terminal is quite as long as two of the preceding,
and terminates in a central point that is furnished with
a solitary hair upon each side of the apex.

The eyes are small and not easily recognized. The
antennz are short, the superior being more robust and
slightly longer than the inferior, and tipped with a few
cilia; in length they equal that of the cephalon and first
joint of the pereion, which being fused together form
the head. The superior antenna consists of four joints,
that is, a peduncle of three and a uniarticulate flagellum,
but which is more slender and longer than the last joint
of the peduncle. The inferior antenna appears to ter-
minate in a similar uniarticulate flagellum. The first pair
of gnathopoda are long and robust, of which the hand is
not larger than the rest of the limb. The carpus is as
long as the propodos, and the dactylos is long, curved,
and slender, forming with the digital process of the
propodos, against which when closed it impinges closely
through its entire length, a sharply-pointed and somewhat
elongate chela. The second pair has the dactylos long
and slender, being hair-like at its extremity and slightly
curved ; the remaining pairs of legs, the true pereiopoda
or walking legs, are subequal in length, of somewhat
slender and feeble proportions, and terminate in small
curved dactyla. ‘The five anterior pairs of pleopoda are
pedunculated and liberally ciliated on the outer and
posterior margins. The posterior pleopoda are biramose,
the inner branch being rather shorter than the ultimate
segment of the pleon; it is single-jointed, but furnished
near the middle, on the inner side, with a small pro-

PARATANAIS RIGIDUS. 143

tuberance armed with two or three minute cilia, and
carrying at the extremity five long and strong hairs.
The outer ramus is about half the length of the inner,
single-jointed, armed near the middle of the outer
margin with a single hair, and also with a_ second
solitary hair on the outer side of the apex.

The species bears a near resemblance to that described
by Lilljeborg under the name of Yanais brevicornis.

Lilljeborg describes that species as having the inner
ramus of the posterior pair of pleopoda biarticulate,
whereas in this it is uniarticulate, but the small ciliated
protuberance near the middle of the inner margin, together
with the circumstance that from that point a slight bend
or change of direction takes place, may have suggested
the idea of a second articulation to the author of that
species, as it was a question which we could not determine
until we had treated the specimen with “‘ liquor potasse.”

So well, otherwise, does this animal correspond with
Lilljeborg’s description, except in the number of joints
of the upper antenna, that had it been described by any
less experienced observer, we should have considered the
two as belonging to the same species, assuming that the
points in question had been misinterpreted.

The only specimen that we have seen of this species
was sent to us by Mr. Robertson, of Glascow, who
*‘dredged it at the roots of Laminaria saccharina,”
near Cumbrae.

144: TANAID®.

ISOPODA. TANAIDA.
ABERRANTIA

Genus—APSEUDES.

Apseudes. Leacu, in Brewster's Edinb. Encycl. vol. vii. p. 404, 1812.
Epwarps, Hist. des Crust. t. iii. p. 138, 1830. LrttsEzore,
Bidrag. kan om de inom Sverige och Norrige forek. Crust. af
Isop. Tanaid. fam. p. 8, 1864.

Eupheus. Rrsso, Hist. des Crust. des Nice, p. 124, 1816.

Rhea. MitnE Epwarps, Ann. Sci. Nat. xiii. p. 292, 1828.

Generic character.—Body elongated. Head and first segment
of the pereion confluent. Upper antenne longer than the lower,
with the first joint of peduncle long and robust, the flagellum
consisting of two elongated articulated filaments. First pair of
gnathopoda chelate; second pair having the propodos trans-
versely dilated. Pleon terminated by a large segment bearing
two long and two short slender filaments.

Tue head and first segment of the body are confluent,
the former advanced in front into a point, forming a
small triangular rostrum, the latter having the sides
dilated and depressed. The eyes are large and borne on
movable footstalks. The upper antenne are robust,
the first joint especially being long and stout; the
flagellum or terminal portion is multiarticulated, and
provided at its base with a slender secondary filamentous
appendage composed of numerous articuli; the lower
antenne are shorter and more slender, furnished with
a small squamiform movable process, as in the Ma-
crourous stalk-eyed crustacea, and terminate in an articu-
lated and gradually attenuated flagellum. The mandibles
are small, slightly truncate, denticulated at the ex-
tremity, and furnished with a three-jointed palpiform
appendage. The outer foot-jaws are confluent at the base,
and terminated by three flattened joints strongly ciliated.

APSEUDES. 145

The first pair of legs are robust, terminated by a
strong didactyle hand. The second pair, though smaller
than the first, are more robust than the following, being
flattened and terminated by a broad hand-like joint, more
or less palmated, the penultimate joint (propodos), having
a small movable finger (dactylos); the five following pairs
of legs are slender and simple. The five segments of the
tail are short, but the last (sixth segment) is elongated,
and terminated by a rounded plate (the telson), on each
side of which is placed a flattened appendage, termi-
nated by one long and one short very slender filiform
branches, being the representatives of the last pair of
tail-feet. The five anterior segments of the tail are
respectively furnished with a pair of appendages, each
consisting of a basal stem supporting two delicate folia-
ceous plates strongly ciliated along their margins. The
egos are borne in a semi-transparent pouch beneath the
breast, which extends from the second to the sixth
segment of the body.

This is one of the most interesting genera of crus-
taceous animals. In some respects, such as the form
of the eyes, the articulated filament attached to the
upper-, the squamiform process of the lower- antenne,
and the cheliferous anterior feet, we perceive a relation-
ship to the macrourous stalk-eyed order of Crustacea; in
other conditions it assimilates the Amphipoda, in which
order Professor Milne Edwards was at the first disposed
to place it, although he subsequently referred it to the
Isopodes Idoteides (Encyclop. portatif. p. 182; Ann. Sci.
Nat. 1830, August), induced to this step by the struc-
ture of the breathing apparatus, which he attributed
to the under side of the segments of the tail; whilst
the soldering of the head and first segment of the body,
and the podophthalmous structure of the eyes, induced

VOL. II. ie

146 TANAIDA.

Dr. Fritz Miller (Archiv. f. Naturg. Jahrg. 1 Bd. p. 1)
and Van Beneden (Ueber der Bau der Scheerenasseln
Assellotes Heteropodes M. Edw.) to attribute it to the
Macrourous Deecapods, each basing his opinion, arrived at
independently, upon the supposition that the union
of the head with the first joint of the body is an
incipient effort in the development of a carapace—the
latter author, moreover, asserting that respiration is
carried on beneath the carapace, although he states that
he has not been able to detect any especial organ adapted
to that purpose.

From this view of the question we must entirely dissent,
first, because the branchial organs in decapod crustacea
are essentially appendages of the coxe or first joints of
the limbs attached to the pereion or pleon: consequently,
all these limbs being posterior to the cephalon, the
organs of respiration cannot be developed beneath it;
second, because the carapace is not developed by a fusion
of the segments of the pereion with those of the ce-
phalon, but by a monstrous production of the integu-
ment of the latter extending back, over, and covering
the segments of the former; and so, in the typical
decapoda, overlying and protecting the segments of the
pereion, and consequently the branchial organs also.

This genus also approaches towards the Podophthalmous
crustacea, and more particularly the Macrourous order, in
the form of the eyes and inferior antennz, whilst it re-
sembles the Amphipoda in the character of the legs and
the general slenderness of the body. It also approaches
the Squille in the character of the pleopoda, and the
Isopoda in that of the posterior pair of pleopoda.

One interesting and, as far as we know, unique feature
in these crustacea yet remains to be noticed. The segments
of the pleon have the lateral walls (long known as the

APSEUDES. 147

epimera of Milne Edwards, called also the pleura by
many authors) existing as articulated appendages, demon-
strating two important features in the homologies of
these parts: first, that they are really portions of the
appendages, being the first joint or coxz of the pleopoda,
as first observed by Mr. Spence Bate in his report on the
Amphipoda ; and second, that since the peduncle consists
of three joints, the second branch in the appendages of
the pleon, as in other parts, is shown to take place in-
variably at the extremity of the third joint.

Of this genus we regret that we have obtained but
few specimens, too few, indeed, to have enabled us to
make complete dissections of the animal.

As yet we know not the form of the male animal ;
it may be similar to that which we figure as the female,
but had not Miiller, Rathke, and Lilljeborg described the
females of Tanais as resembling the male, we should have
suggested that these species were females of Tanais, for
it is a singular fact that although of the latter genus we
have examined some hundreds of individuals, we have
never yet seen one possessing the features of a female.*

* We are bound, however, in this place to recall attention to Rathke’s
figure of his Crosswrus vittatus with a large incubatory pouch filled with
large eggs.

148 TANAIDA.,

ISOPODA, TANAID.
ABERRANTIA.

SIE Ieee re
OKC
Ah A Lo \

\ \)
i [ '

APSEUDES TALPA.

Specific character. Front of cephalon terminating in a porrected point, its
dorsal surface irregular. Body finely but sparsely setose. Pleon very hairy
at the sides. Terminal segment of the pleon long and slender. First pair of
gnathopoda large ; the carpus with two lobes on the under edge. Palm of
the propodos with a tooth in the middle; dactylos with a tooth at its base.

Length one-third of an inch.

Cancer (Gammarus) Talpa. Mowntacu, Trans. Linn, Soe. ix. p. 98, t.6, f. 6.

Apseudes Talpa. Lracu, Edinb. Ene. vii. p. 404. Trans. Linn.
Soc. xi. p. 372. Suppl. Enc. Brit. i. p.
428. SamMovELLy, Ent. Compend. p. 109.
Lamarck, Hist. Nat. Anim. sans. vertebr.
v. p. 290. Minne Epwarps, Crust. iii. p.
140. Cuvier, Régne An. Edit. Crochard
Crust. pl. 62, fig. 1. Wuurrs, Brit. Mus.
Cat. Brit. Crust. p. 67. Pop. Hist. Brit.
Crust. p. 226. Gossp, Man. Mar. Zool. i.
fig. 245.

Lupheus Talpa. Desmarest, Cons. Crust. p. 285, t. 46, fig. 9.

APSEUDES TALPA. 149

Tue figure of this species, published originally by
Montagu, and which has been copied by all subsequent
authors (except Prof. Milne Edwards), was so ill drawn,
that the true relations of the animal could not possibly
be determined. The head and first segment of the body
were confounded together into a triangular mass, desti-
tute of any trace of articulation, and the tail was repre-
sented as elongate-conic in form, and composed of
twelve very short joints, all being very setose. The
figure given by Prof. Milne Edwards, quoted above, was
made by him from the original specimen of Montagu,
preserved in the British Museum, and represents the
animal more faithfully ; the lower antenne are, however,
drawn too small and short, a sketch made by us from the
same individual many years ago, representing the an-
tenne as nearly equal in length—possibly from the
flagellum of the upper pair being broken off; neither
does Prof. Milne Edwards’s figure give a correct idea of
the dilated structure of the second pair of hands.

The segments of the body are transverse, serrated
along the hinder margins, the sides being rounded; the
five basal segments of the tail are very short, the sixth
being as long as all the rest together, and terminated in
an obtuse point, at the sides of which are affixed the
terminal pair of tail-legs, which are transformed into
a very long setaceous filament, having a shorter one at
its base. The segments of the tail are very pilose at the
sides. The upper antenne have a strong basal joint,
crenulated along its inner edge, in the middle of which
is a small, setose swelling; the following joint is strong,
but very much shorter than the preceding, followed by
a smaller joint, and the terminal filament, or flagellum, is
very slender and multiarticulate, the secondary filament
at its base being half the length of the primary one, and

150 TANAIDA.

also composed of a considerable number of articuli. The
lower antennze are much shorter than the upper, the
basal joints being the thickest, the third furnished with a
small oval squamose plate at its extremity, the terminal
joints or flagellum slender, extending beyond the base
of the flagellum of the upper. The upper surface of
the head is uneven (the fissures probably marking the
point of fusion of the head with the first joint of the
body), terminating in front in a porrected point. The
eyes are affixed upon a pair of short, somewhat kidney-
shaped lobes. The outer foot-jaws are short, and ciliated
on the inner margin. The mandibles are elongated,
gradually narrowing to the tip, which is denticulated ;
they bear a slender, three-jointed appendage, the first
joint of which is very short, the second and third longer
and nearly equal in length, the latter furnished with long
bristles at the tip, set on at right-angles to the joint.
The first pair of legs are robust, the wrist is swollen,
and armed on its under side with two tubercles a short
distance apart; the hand is large and oval, its inferior
angle produced into a finger, having a tubercle on its
inner edge near the middle, against which the true finger
impinges, the latter having a small tubercle on its inner
edge, close to its base. The second pair of legs have the
hand developed into a large, transversely flattened ovate
joint, having several strong spines on its margins, so as
to give it a digitated appearance, the terminal finger
resembling one of these spines. The third and fourth
pairs of legs are slender, having a forward direction, the
penultimate joint is very slender, except at the tip, which
is dilated and fringed with spinous hairs, the slender
terminal finger inserted on its posterior surface within
the tip.

The fifth pair of legs are also slender, but with a back-

APSEUDES TALPA. 15]

ward direction (as have also the sixth and seventh pairs) ;
in all these legs the hand is armed near the base of the
under margin with a strong spine, against which the
extremity of the finger, when closed, impinges, this joint
being dilated in the two posterior pairs, and strongly
ciliated along both its inner and outer margins and apex,
the finger being planted anteriorly within the palm of
the concave hand.

The ventral appendages of the five segments of the
tail are free, consisting, in each segment, of two pairs of
delicate, elongate-ovate plates, each pair attached to a
basal, three-jointed footstalk, the first joint of which
consists of a plate, having the posterior margin serrated
and furnished with several long bristles, the anterior
margin being fringed with plumose hairs, as also the
inner margin of the third joint, as well as both those of
the subtending plates.

The sixth segment is semi-ovate, and furnished at each
side with an appendage formed of a single-jointed pe-
duncle, supporting one long and one short filamentary
branches formed of numerous articuli, increasing in
length as they diminish in size towards the distal ex-
tremities.

We only know the female of this species.

The incubatory pouch is formed of very slender, semi-
transparent plates, which permit the large eggs enclosed
to be distinctly visible.

The general colour of the animal, when alive, is
yellowish-white, the hairs and divisions between the seg-
ments of the body partaking more of the former colour.

_ Colonel Montagu took this species on the large scallop
(Pecten maximus) at Salcombe, on the South Devonshire
coast. It has also been taken off Guernsey, by the Rev.

152 TANAIDA.

A. M. Norman, and we have taken it, in company with
the late Mr. Barlee, in Plymouth Sound. Mr. W. P.
Cocks found it, rarely, amongst Sertularie and other
trawl refuse, in the middle of the month of April.

APSEUDES TALPA. (EXTREMITY OF FEET.)

APSEUDES LATREILLII. 153

ISOPODA, TANAID,
ABERRANIIA.

APSEUDES LATREILLITI.

Specific character. Body smooth, destitute of hairs on the sides. Head
terminating in front in a deflexed point. Terminal segment of the tail not
more than half the length of the preceding portion of the pleon. First pair
of gnathopoda moderately large, the hand produced at its lower angle into a
strong finger, which is densely hairy, but destitute of tubercles or spines, as
is also the true movable finger.

Length one-fourth of an inch.

Rhea Latreillit (2) Minyn Epwarps, Ann. Sci. Nat. V. xii. p. 288, pl. 13a.

THE specimen from which the accompanying figure is
drawn bears so great a resemblance to Milne Edwards’s
figure of Rhea Latreillii that we have no doubt as to the
identity of the two animals. The deflexed rostrum, or
advanced point of the head, the comparatively large size
of the second pair of feet, the more slender hand with
the smooth fingers in the first pair of limbs, are all
characters observable in both.

The small central point of the head, or rostrum, is
slightly down-curved. The orbital process is produced
to a pointed apex. The superior antennz have the pe-
duncle smooth, and the secondary appendage of the
flagellum scarcely half as long as the primary. The
inferior antenna reaches but little beyond the peduncle

154 TANAIDA.

of the superior. The first pair of hands have the carpus
rather longer than the propodos, and ciliated along the
inferior margin; the propodos has the inferior digital
process liberally ciliated over the surface, and more so
along the margins; the dactylos is curved, smooth, and
inversely corresponding in form to the margin of the
opposing finger. The second pair of hands have the
margins of the carpus and propodos fringed with strong
spines, and the finger planted in the middle of the ex-
tremity of the flattened propodos. The succeeding legs
appear not to differ much from those of the preceding
species, except the posterior pair, which, instead of having
the propodos fringed with cilia, have it armed with short,
stiff spines, that increase in length towards the distal
extremity. In most other points this species appears to
differ but little from the preceding.

We have seen but a solitary specimen, which was
sent to us by our esteemed correspondent the Rev. A. M.
Norman, who obtained it on the coast of Northum-
berland.

This specimen was a female, and carried a mass of
large, circular, orange-coloured eggs between the second
and penultimate segments of the pereion, beneath a
transparent membranous sac.

M. Milne Edwards first described this species in the
Ann. des Sci. Nat. t. xili. p. 288, pl. 13a, fig. 1-8, from
a specimen dredged on an oyster-bank of Port Louis;
but in his description in Hist. des Crust. t. 11. p. 141,
he gives the coast of Brittany as the habitat.

The extreme paucity in the number of the specimens
both of this and the preceding species, that have been
recorded, induces us to believe that the true habitat and
habits of the genus have yet to be discovered.

ANTHURIDA. 155

ISOPODA. ANTHURID 4.
ABERRANTI4.

Fam.—ANTHURIDA. (Anthurade—Leach.)

THE animals in this family are very long and slender,
the head distinct from the pereion, the antenne very short
and nearly equal in length, the first pair of legs large
and subchelate, the remaining six pairs nearly equal
in size and uniform in shape, the pleon furnished with
biramose squamose appendages, terminal pair of pleopoda
transformed into a pair of scale-like appendages at each
side of the terminal joint.

The head is nearly oval, with the eyes small, oval,
formed of but very few lenses, and placed near the
anterior angles of the head, behind the antennz, which
are very short and gradually attenuated to the tip. In
the figures in page 160, they are represented as they
appeared to us under a lens, in the very ill-preserved
type of the genus, originally described by Montagu,
now in the British Museum. In specimens preserved
in spirit of a second species, contained in the Hopeian
Collection, the upper pair are placed a little apart at
the base, whilst the lower pair, which are the most
robust, arises close together, their basal joint being por-
rected and brought into contact with each other along
their inner edge, thus forming a protection from above
to the oral organs. The upper pair of antennz are
composed of a three-jointed peduncle and a four-jointed
flagellum, the terminal joint furnished with a long pencil
of hairs at the tip. The lower, and more robust pair,
consist of five joints, of which the second and third
are shorter than the first and fourth; the terminal joint is
conical, and furnished at its tip with a pencil of hairs.

156 ANTHURIDA.

The mouth, of which the peculiar structure has been
overlooked by all previous writers, is evidently formed
for suction, and consists of a narrow process extending
along the anterior half of the under side of the head,
and porrected in a point in front.*

The mouth is closed beneath by a pair of foot-jaws,
each composed of two oblong, flattened joints, the
second of which is slightly curved and somewhat pointed
to the tip, and armed along its inner edge with a series
of long hairs. Within this pair of foot-jaws appear
two long and extremely slender, nearly straight, sete,
of which the extremity, along the inner edge, is finely
retro-serrated. We regard this pair of organs as the
second pair of maxillee, very similar in general structure
to those of the genus ga and its allies. We have found
no trace of the first pair of maxille, but the mandibles
appear to be represented by a pair of elongated, pointed
organs, having a three-jointed palpus, bearing a close
general resemblance to the mandibles and their appen-
dages in Limnoria, Aiga, &c. These organs rest within
or beneath an elongated, conical, horny piece, of which
the tip appears to be deeply bi-sinuated, forming the
upper lip, and within the mouth we find another elon-
gated, single organ, thickened at the base, which may
possibly represent the ‘ levre inférieure’ of Savigny.

The seven following segments of the body are quite
distinct, the anterior ones being the longest, whilst the
last, or seventh, is the shortest of them all. The incu-
batory pouch in the females extends from the second
to the seventh segment.

The tail is composed of six segments, the four an-

* This description is made from individuals of the second species, above
alluded to, to which the name of Par. Costana has been applied by Prof,
Westwood.

ANTHURA. 157

terior of which are soldered together; the fifth is a
small segment with the hind margin raised and notched
in the middle, and which supports the latero-caudal
plates; and the sixth forms the large terminal central
plate of the tail.

The family comprises three genera, of which the two
following are British.

Genus—ANTHURA. (Leach.)

The body is very slender, elongated, and somewhat
triquetrous, having the head and segments of the body
quite distinct from each other; but the four anterior

SHAPE OF BODY.

segments of the tail are confluent, and so closely attached
together, that, in fresh specimens, or in those preserved
in spirits, the articulations are not recognizable; the
penultimate segment of the tail is short, having on each
side a pair of scale-like appendages, representing the
terminal pair of tail-legs.

The pleopoda consist of, at least, four pairs of
oval plates, strongly ciliated, on each side of the ventral
surface of the basal segments of the tail, They are
of nearly equal size, and arranged so as to lie longi-

158 ANTHURIDA.

tudinally, but, in the first pair alone, the outer division
is very much narrower than the inner division. The
terminal pair of tail-feet are transformed into a pair of
crustaceous plates, affixed to each side of the penultimate
segment at its base; the inner plates have a transverse
articulation beyond the middle,* and the outer plate
is affixed vertically and falls back, when at rest, upon
the dorsum of the terminal joint, fitting into the de-
pression formed by the transverse carina on that segment.
The lower figure, P z, in page 160, represents the lateral
view of the tail of A. gracilis, being the four basal seg-
ments (represented as entirely soldered into one joint),
beneath which is seen three pairs of tail-feet in a mass,
the long appendage arising from the lower anterior angle
of the segment representing the anterior large pair that
covers the rest as an operculum; the fifth segment of
the tail is also shown as distinct, followed by the large
laterally-deflexed portion of the terminal pair of tail-feet
or scales which it supports; the articulated extremity of
the two inner divisions of this pair of appendages, and
the truncate extremity of the middle portion of the tail
being also shown in the deflexed portion of the figure.

The left-hand figure, P’”, represents the ventral surface
of the two terminal segments of the body, and of the tail,
showing the inner division of the anterior pair of tail-
feet, concealing the outer division of the same pair as
well as the whole of the remaining pairs of the organs.
Fig. p represents the outer division of the left-hand pair
of the first respiratory tail-feet, and fig. p’, a portion
of its lateral, deeply ciliated margins, showing the in-
sertion of the ciliz.

The anterior pair of feet are strong but short, not

* In Mga this articulation is oblique, and extends to the insertion of the
outer plate.

ANTHURA. 159

extending beyond the front of the head; the hand is
ovate, protected at the base of its inner margin by the
produced extremity of the preceding joint; the finger is
strong, and terminated by a distinct unguis. The six
other pairs of legs are much more slender and simple,
terminated by a short, rather strong, curved finger, and a
distinct terminal unguis.

The very elongate and slender form of the animals
of this genus gives them a certain amount of resem-
blance to the species of Arcturus, and has led to their
being placed in the family of which Jdotea is the type; but
Dr. Leach long ago had the tact to perceive their claims
to form a distinct family, and, although their general
form, short antennz, and strong fore legs, give them a
certain similarity to Tanais, yet we apprehend (now that
their real structure has, for the first time, been described
from a minute analytical examination of their oral
organs) that their true affinities will be admitted to be in
the immediate neighbourhood of the Agide, one species
of which at least, Conilera cylindracea, approaches them
in its elongated cylindrical form; indeed, Dr. Leach
suggested that this animal might possibly be referable
to the family Anthuride, and, accordingly, in Mr. White’s
catalogue of British Crustacea, it is placed as a second
species under the name of Anthura cylindrica, appearing
again in a subsequent page, in its proper place and name,
as Conilera cylindracea.

160 ANTHURIDA,

ISOPODA. ANTHURID&,
ABERRANTIA.

ANTHURA GRACILIS.

Specific character. Long, slender, sub-compressed, sub-cylindrical. Seg-
ments of the body with a strong, lateral ridge ; terminal segments sub-trian-
gular. Four anterior segments of the pleon soldered closely together, forming
a subtriangular mass ; middle tail-piece keeled down the centre, with three
very delicate, longitudinal, raised lines, down the sides of the keel; apex
truncate ; apex of the inner division of the lateral scales obliquely truncated,
and crenulated.

Length 5 lines.

Oniscus gracilis. Montaau, Trans. Linn. Soe. ix. p. 108, t. 5, fig. 6.

Anthura gracilis. Leacu, Edinb. Encye. vii. p. 604. Trans. Linn. Soe.
xi. p. 366. Suppl. Enc. Brit. Dusmarest, Cons.
Crust. p. 291, t. 46, fig. 13. Samovenie, Entom.
Compend. p. 107. GuériIn Meénevittr, Icon.
R. An. t. 30, fig. 6. Mi~ne Epwarps, Crust. iii.
p. 136, t. 31, fig. 3. Wuure, B. M. Cat. Brit. Crust.
p. 67. Pop. Hist. Brit. Crust. p. 225, pl. 12, fig. 4.*
GossE, Man. Mar. Zool. i. fig. 248.

* Tn this figure two segments of the body and one of the pairs of legs are
omitted.

ANTHURA GRACILIS. 161

Tus species is well defined by the strong, raised,
lateral margins to the segments of the body and tail,
by the consolidation of the basal segments of the latter
almost into a solid mass, the articulations being, how-
ever, clearly indicated by impressions on the under edge
of the lateral margin, and especially by the characters
of the terminal segment of the tail and its appendages,
noticed in the specific characters given above. It is,
however, rather difficult to describe precisely the curious
construction of this terminal portion of the body.
Montagu says that ‘the body is terminated by
five large caudal appendages truncated at their ends,
these are deflected nearly at right-angles with the body,
the middle one fixed, and the lateral ones jointed and
spread a little upwards in a semicircular form.” The last
term is not, however, at all expressive, and should,
doubtless, have been ‘‘ semicylindrical,” since the ap-
paratus, when open, forms a concave cup-like disc, and
when at rest, from being affixed vertically, the outer
plate falls back and shuts down upon the dorsum of the
middle tail-plate, like the two wings of a closed triptych.
The irregularly crenulated margin of the extremity of
these caudal plates also affords ancther distinctive cha-
racter. Not having seen fresh specimens of this species,
we are unable to give a more precise description of the
antennz than is conveyed in our generic observations.

The fore legs, although not longer than the succeeding
pairs, are very much more robust, with a large, elongate-
ovate hand, the upper basal angle being swollen, and the
palm having a deep incision along its outer half (which
we believe to be caused by the elongation of the outer
and lower angle of the preceding joint) which is slightly
rugose. The other legs are much more slender, with the
joints of nearly equal length, the fifth and sixth having

VOL. Il. M

162 . ANTHURIDA.

a small spine at the extremity of the under margin; the
terminal dactylos also ends in a small, sharp-pointed
unguis.

The colour of the animal is pale yellow, clouded with
rufous.

The species was first taken on the Coast of Devon-
shire, by the late Colonel Montagu, and since by Mr.
Barlee, at Falmouth, and off the Thatcher Rock, Torbay,
by Mr. Walker, of Exeter.

The following vignette represents some fishermen
drawing in a seyne full of fish, on most of which these

crustacea attach themselves.

SEYNING.

PARANTHURA. 163

Genus—PARANTHURA.
Oliska (2). Risso. Hopz.
Generic character. Like Anthura, except in the structure of
the pleon, which has the several segments distinctly articulated
with each other, and carries the normal number of pleopoda.

THE animal is long, slender, and linear; the head
distinct from the first segment of the body, the latter
consisting of seven segments, the whole being nearly
subequal, except the last, which is shorter than the
preceding. The tail is short, being about one-eighth of the
length of the entire animal, consisting of seven separate
segments, six of which support appendages. The eyes
are sessile and ovate. The superior pair of antennz are
short, being about the length of the head, each being
formed of six joints, gradually diminishing in size to
the last. The inferior pair is longer and much stronger
than the superior, and five-jointed, the large basal joint
being attached to the head by a short, indistinct joint ;
the second, third, and fourth joints gradually increase in
length, the fourth being not quite so long as the basal
joint; the fifth joint is nearly as long as the fourth, and
gradually attenuated to the tip, furnished with long
sete, and terminated by a very minute, exarticulate
point. The three anterior pairs of legs (namely, the
two pairs of gnathopoda and first pair of pereiopoda)
are formed upon the same type, and terminate in a sub-
chelate hand. The four posterior pairs of legs are more
slender, and attached in an opposite direction to the
anterior pair. Each of the tail appendages (or pleopoda)

consists of two membranaceous plates for respiration ;
M2

164 ANTHURIDA.

the first pair are large, and have the external branch
narrow, and attached so as to lie upon the outer margin
of the other, which is ovate and foliaceous; the four
pairs next succeeding are ovate, membranous, and folia-
ceous. The posterior pair are articulated to the sixth
segment dorsally. The upper and outer branch is folia-
ceous, and affixed vertically; the inner and inferior
branch is two-jointed, and placed horizontally below
the plane of the middle tail-piece, which is ovate, and
terminates in an obtusely pointed apex.

There is a species of this genus, an inch in length, in
the Museum of the Jardin des Plantes, from Port
Western, New Holland.

PARANTHURA COSTANA. 165

ISOPODA, ANTHURID.
ABERRANTIA,

PARANTHURA COSTANA.

Specific character. Cylindrical; segments of the body of nearly equal
size ; middle tail-piece not carinated, ovate at the extremity ; inner branch
of the sixth pair of tail appendages articulated and rounded at its extremity.
Hand of the first pair of legs produced into a minute, reflexed tubercle at its
extreme inner base.

Anthura gracilis. Mine Epwarps, Hist. des Crust. iii. p. 186, pl. 31,
fig. 3, but not of Montagu, ut supra.

Idotea penicillata. Risso, Hist. N. Crust. Nice, 1816, p. 137, pl. 3, fig.
10 (?). Dusmarest, Crust. p. 315.

Oliska penicillata. Risso, Hist. N. Eur. Merid. 5, p. 113. Hops, Cat.
Ital. Crust. p. 27 (?).

In the Hopeian Collection of Crustacea are preserved
several specimens of this species, fixed on card, to which
is attached a label ‘*S. W. Coast of England on Broad
Sea Weed.” It differs from A. gracilis in its more
cylindrical form, the sides of the body wanting the
raised lateral margins, the distinct articulation of the

166 ANTHURID.

five basal segments of the tail, the smooth surface of
the middle tail-piece, oval at its extremity, the very
distinct and oval terminal division of the inner plate of
the side appendage of the tail, and the smaller and
narrower size of the outer division. The hand of the
fore pair of legs also wants the notch along its under
edge. It is of a pale bone colour, covered with minute
black dots. The mouth is enclosed between horny
plates (+) and furnished with a pair of straight, elon-
gate-conic mandibles, pointed at the tip, having a large,
three-jointed, palpiform appendage fixed at its base on
the inner edge. The maxilla consist of a pair of long,
very slender, slightly curved, lancet-like pieces, retro-
serrated at the apex, and the mouth is closed beneath
by a broad pair of foot-jaws, which are terminated by
two large, flat joints, the apical one being strongly
ciliated.

In all these particulars it perfectly agrees with other
specimens preserved in spirits in the same collection,
with a label inscribed ‘‘ Anthura gracilis,” in the hand-
writing of Signor Costa, of Naples, with whom Mr.
Hope was long in friendly communication upon the
marine animals of the Mediterranean. On referring to
Mr. Hope’s catalogue of the Mediterranean Crustacea,
we find only one species of Anthura indicated with the
name of A. gracilis, which, from a copy marked by S.
Costa, we find to be in his collection; and we have,
therefore, no doubt that the species was communicated
by him to Mr. Hope. We therefore at first hesitated
to consider the species as a real native of this country
(fearing some confusion might have occurred as to the
labels of the South Western Coast specimens), and, in
honour to Signor Costa, we proposed for the species the
name of Paranthura Costana. Whilst, however, this

PARANTHURA COSTANA, 167

sheet was in the printer’s hands, we had the pleasure to
receive from the Rev. A. M. Norman, specimens taken
by himself off the Channel Islands ; so that the claim of
the species to be regarded as British is fully confirmed.
The figure given by Mr. Milne Edwards in the work
above referred to as A. gracilis, is no doubt intended for
this species, since it was taken on the neighbouring
coast of La Manche. But, since he mistook it for
Anthura gracilis, the retention of his specific name,
founded, as it was, in error, would lead to confusion ;
we have therefore thought it desirable to adopt another
not open to the same objection.

BRIGHTON FISHERMEN.

168 ANCEIDA,

ISOPODA. ANCEIDA,
ABERRANTIA,

ANCEID.

Praniziens. Mitne Epwarps.

Pranizide. Dana.

Pranizade. Van BENEDEN.

Decempedes. LATREILLE.
(Males) Gnathides, Gnathonii, Gnathionii, Leacu.

Ancéens. Mitye Epwarps.
(Females) Praniziens prop. dites. Minne Epwarps

Pranizide. Wuitr. Dana,

Tue head has the first (or more probably the first and
second) segments of the body fused with it; it is very
large, and flattened, or dorsally concave in the males;
quadrate or ovate, and of moderate size, in the females.
The antennz are small or of moderate length, nearly
equal, inserted widely apart, composed of a three-jointed
peduncle and an articulated flagellum, The mouth is
very anomalous in its structure, differing very greatly in
the adult from the young, as well as in the ‘opposite
sexes of the same species. In the adult males the front
of the head is armed with a very large pair of porrected
mandibles; in the early stages the mouth in both sexes
is suctorial in its character. The- body is composed of
only five segments, of which the three posterior are
soldered together in the females, so as to form a large,
oval mass. There are only five pairs of slender, simple
legs. The pleon is of small size and narrow, but well
developed, consisting of six segments, of which the last
is small and triangular: each segment being provided on
its ventral surface with a pair of delicate, membranous,
biramous, squamiform appendages, which are entirely
free, and not covered by a larger anterior pair or oper-
culum, The terminal pair on each side form, with the

ANCEIDA. 169

middle tail-piece (telson), a five-lobed organ useful in
swimming to guide the animal.

The animals composing this most anomalous family
have, until quite recently, been considered as forming,
not only two distinct genera, but even have been ar-
ranged by M. Edwards and Dana as distinct tribes. The
observations of M. Hesse, of Brest, however, leave no
room to doubt that the two supposed genera, Anceus and
Praniza, are but the males and females of one genus,
although his assertion that they are but different
phases of one and the same animal cannot be ac-
cepted. It seems, however, sufficiently proved, that
one of these animals of small size, which would hereto-
fore have been unhesitatingly called a Praniza, if kept in
confinement, becomes developed into a female (Praniza),
while a second, only slightly differing, becomes a fully
developed male (Anceus). We therefore adopt the sug-
gestion of M. Hesse (not indeed for the reason which he
assigns, that a Praniza is transformed into an Anceus—
a statement which our observations will sufficiently dis-
prove), but in conformity with the usual rule of priority,
as well as that of accepting the denomination of the
male rather than that of the female animal, and, ac-
cordingly, retain for the group the family name of
Anceide. Strictly speaking, however, the name Gnat-
hiide should be given to the family, Leach’s name
Gnathia having ‘the priority in point of date over that of
Anceus ; but as Leach himself omitted the genus in his
later works, and there is a well acknowledged genus,
Gnathium, amongst the heteromerous beetles proposed by
Kirby, we have preferred using the generally adopted
name of Anceus.

170. ANCEIDA.

ISOPODA. ANCEID A,
ABERRANTIA.

Genus—ANCEUS.

Gnathia. Laon, Edinb. Encye. (male).
Anceus. Risso, Crust. des Nice, p. 51, 1816 (male). Dusm.
Praniza. Lracu, MSS. Risso, Latr., Lam., Desm. (female).

Generic character. Male. Cephalon large, broad, quadrate.
Pereion having the first two segments absent, or fused with the
cephalon; the two next separated from the three posterior.
Pleon with six segments, the posterior terminating acutely.
Eyes large and placed at the antero-lateral angle of the head.
Antenne simple, subequal. Mandibles anteriorly produced from
the anterior margin of the cephalon. First gnathopoda wanting.
Second pair of gnathopoda transformed into the outer appendage
of the mouth. Pereiopoda subequal, the three posterior pairs
reversed. Pleopoda biramose, posterior pair planted on each
side of the caudal segment. These are the characters of the
animals: long known only as Anceus.

Female. Cephalon small, quadrate. Pereion having the first
two segments wanting or fused with the cephalon, the two suc-
ceeding distinct, small, subequal; the three last fused together.
Pleon as in the male. This character distinguishes the animals
long known as Praniza.

Tue history of this genus is so remarkable as to merit
a detailed account. The earliest record of one of these
animals is contained in the microscopical work of Slabber,
‘* Natuurkundige Verlustigingen,”’ republished at Nu-
remberg in 1775, under the title of ‘‘ Physicalischen
Belustigungen,” 4to, p. 37, pl. 9, where the author gives
the representation, and ‘‘ Wahrnehmung eines Oniscus
marinus,” being a satisfactory figure of a Praniza, which
he had found on the shores of Holland, during four
months of the year, in considerable quantities, and which
exhibited great agility in the water. This figure was
copied by Latreille in the great ‘‘ Encyclopédie Métho-

ANCEUS. yt

dique, Crustaces,” pl. 329, fig. 24, and described in the
text as Crustace du genre Praniza du Docteur Leach.”

In the seventh volume of the “ Transactions of the
Linnean Society,” Col. Montagu published the descrip-
tion and figure of an animal under the name of Cancer
maaillaris, which proves to be the male of this genus;
and in the ninth volume of the same work, he also pub-
lished a figure and description of a female, under the
name of Oniscus ceruleatus.*

In “ The Edinburgh Encyclopedia,” vol. 7, Dr. Leach,
in adopting the Latreillian principles of classification to
the Crustacea, proposed the generic name of Gnathia for
the Cancer mazillaris. He had previously, as above stated,
proposed the MS. name of Praniza for the female.

In “ Hist. Nat. des Crust. de Nice,” 1816, p. 52, pl. 2,
fig. 10, Risso subsequently described the male of a Medi-
terranean species under the name of Anceus forficularis.

In the fifth volume of ‘‘ Loudon’s Magazine of Na-
tural History,” the late Dr. Johnston published some
observations on the genus Praniza, and added the descrip-
tion and figure of a second species, Praniza fuscata,
observing that these animals, by means of their legs,
are able to creep on the bottom of the sea, which they
do slowly, but they swim with greater rapidity, pro-
pelling themselves forward by the quick motions of the
series of ciliated fins placed beneath the tail.

The remarkable structure of what is supposed to be
the respiratory apparatus of these animals (intermediate
as it is between that of the typical Amphipoda—namely,
a series of free appendages—and that of the typical
Isopoda—in which the appendages are enclosed by a
bivalve operculum), induced Professor Westwood to com-

* This figure was also copied in the Encyclopédie Méthodique, pl. 336, fig.
28, but under the erroneous name of Oniscus (Celino ) thoracicus of Montagu.

V%2 ANCEIDZ.

municate a memoir on the subject to the meeting of the
British Association at Oxford, in 1832 ;—a translation of
which, with additions, containing the description of some
supposed new species of Praniza, was published in the
“Annales des Sciences Naturelles.” Other supposed
species of the two sexes of this genus were published
by other authors, namely, Praniza branchialis, of Otto
(in “ Nova Acta” of Bonn, vol. xiv.) ; Praniza ven-
tricosa, plumosa, and mesosoma, of Risso (‘‘ Hist. Nat.
Eur. -Merid.” vol. v.); Praniza Reinhardi, of Kroyer
(“ Gronlands Amfipoder”); Anceus rapax, of Milne Ed-
wards (‘* Hist. Nat. Crust.” vol. iii.) ; Anceus vorax, of
Lucas (“Annales Soc. Ent. France,” 1849); Praniza
mauritanica, of Lucas (‘ Op. Cit.”); and Praniza obesa, of
Lucas (“ Op. Cit.” and “ Hist. Nat. Alger,” tome i.).

Whilst establishing the genera Gnathia and Praniza for
the two sexes of this genus, Dr. Leach had the tact to
perceive the possibility of their being sexes of one and
the same species, observing (‘* Edin. Encyc.” vii. p. 402)
that ‘‘ Mr. Leach supposes that Oniscus ceruleatus, of
Montagu, is the female of this animal” (Gnathia termi-
toides, or maxillaris, Mont.). Hence possibly the reason
why Dr. Leach did not introduce his MS. genus Praniza
into any of his works; indeed, he omitted Gnathia in
his celebrated memoir published in the ‘‘ Transactions
of the Linnean Society,” vol. xi. 1815.

In November, 1855, M. Hesse communicated a me-
moir to the Académie des Sciences, of Paris,* in which
he announced the startling fact that Praniza was but the
larva state of Anceus, and that, by a true metamorphosis,
Praniza was transformed into Anceus.

In the beginning of the following year, 1856, our

* Comptes rendus, Nov. 1855, March 1858. Ann. des Sci. Nat. 1858,
t. ix. p. 89.

ANCEUS. 173

friend, A. H. Haliday, Esq., communicated to us spe-
cimens both of Anceus and Praniza, which he had first
taken in 1847, on the shores of Strangford Lough, in
the North of Ireland, in some numbers, and in equal
proportions, in the semmer, although in the month of
February the Pranize were much less abundant than the
Ancei. My. Haliday’s specimens were taken in small
cavities in the surface of the clay, under stones, some-
times singly, oftener two, and even three and four in
each hole; the smaller green ones were few in, com-
parison. The new-born young of the Praniza have all
the characteristic form of the parent, but the posterior
thoracic segments not so completely confounded to-
gether.*

Referring to M. Hesse’s memoir, Mr. Haliday ob-
served in his communication to us, that ‘ notwithstand-
ing their constant association, and the fact that the
Anceus is always of pretty uniform size, and Praniza
varies from about the same down to the smallest size,
I should never have guessed that the latter was the larva
of the former; and yet I do not understand how to com-
bine it with my posvtive observation of Praniza producing
young—the very eyes of which (before birth) were
visible through the transparent integuments of the
parent.” We are able fully to confirm this statement,
as some of Mr. Haliday’s specimens of the Pranize still
exhibit the mass of eggs within the incubatory pouch,
and from others the minute young have escaped in the
spirit in which they are preserved.

Mr. A. White, in his “ Popular History of British
Crustacea,” 1857, still further confused the matter by
observing that ‘‘ there is some likelihood that Anceus may
prove to be one of the stages of Praniza.”

* Annals Nat. Hist. 1848, vol. i. p. 65.

174 ANCEIDA.

In 1858, Mr. Spence Bate communicated a memoir
‘on Praniza and Anceus, and their Affinity to each
other,” in the ‘f Annals of Natural History,” 3 ser. vol. ii.
pl. 6 and 7, in which, after a careful description of the
structure of the two, Anceus and Praniza, and a review of
the statements of previous writers, and especially of the
memoir of M. Hesse, he arrived at these conclu-
sions :—

1. That (upon M. Hesse’s observation of Anceus pro-
ducing young) Anceus is an adult animal.

2. That (upon his own observation of Praniza pro-
ducing young) Praniza is an adult animal.

3. That Praniza, consequently, cannot be developed
into Anceus.

4. That Anceus is a distinct genus from Praniza.

5. That the males of both genera have yet to be dis-
covered.

In 1861, M. Van Beneden, in his ‘* Recherches sur la
Faune littorale de Belgique, Crustacés,” published a de-
tailed description, with figures, of the Oniscus (Praniza)
marinus, of Slabber, as the ‘‘ état larvaire,’’ and of the
Anceus as the ‘‘ état adulte ”
ceded by a history of the genus, and of the observations

of the same animal, pre-

of Messieurs Hesse and Spence Bate, together with a
supplemental note from the former to the objections of
the latter :—

*‘ Si vous prenez des Pranizes d’une certaine dimen-
sion, c’est-a-dire, pres de l’époque de leur transforma-
tion, vous n’avez plus, au bout de quelques jours, des
Pranizes mais des Ancées des deux sexes—quelques jours
avant la transformation des Pranizes femelles en Ancées
les ceufs qui préexistent s’apercoivent a travers la peau, et
si M. Bate avait vu la suite de cette operation, il eut
constaté que sa Pranize était devenue Ancée.”

ANCEUS. Vio

In 1864, M. Hesse published his detailed “ Mémoire
sur les Pranizes et les Ancées,” 4to, Paris, with a vast
amount of supplemental materials, from which he de-
duced the following results :—

1. That Praniza is only a ‘‘ phase de la métamorphose
de la larve en Ancée.”

2. That at the end of the larval state, in which
sexual differences are not perceivable, these crustacea
are transformed into males and females.

3. That the male and female are completely distinct
in form, and that the young state, or Praniza form, is so
unlike that of the two sexes, that it may be mistaken
for a different species.

4. That the female of Anceus had hitherto been totally
unknown.

_5. That during their larva, or Praniza form, they are
parasitic on fishes, with a mouth fitted for sucking blood,
and that after quitting the fishes and assuming the Anceus

’

form, they live “a terre” with a greatly modified form
of the mouth, furnished with formidable mandibles.

6. That the Anceus form is that of their final meta-
morphosis.

In contrasting these results with the plates which
accompany M. Hesse’s memoir, we cannot but express
our conviction that his conclusions are far from being
borne out by his own recorded observations.

If the student will but turn to M. Hesse’s elaborate
memoir, we think that we shall be able even thence to
demonstrate the correctness of our own conclusions on
these anomalous animals. In plate 1, the figures 9 and
11 nearly correspond in the natural size of the objects,
but materially differ in form; whereas all the larve in
fig. 30 correspond only with fig. 11. This latter cir-
cumstance probably may be only the result of the artist’s

176 ANCEID&.

speed. Now we contend, and our own observations con-
vince us, that fig. 10 is the larval stage of the male, and
that fig. 11 is a similarly advanced condition, or the larval
stage “of the female. At the period when the larve
quit the ovigerous pouch of the parent, the simi-
larity of the two sexes, it is true, is very close, and
not readily distinguishable; but even at this early period
the transparent membranes enveloping the terminal seg-
ments of the pereion, seen in the woodcut in page 177,
indicates a form more nearly approaching to that of the
adult female (or Praniza form of Anceus), than to that of
the male or true Anceus.

We have examined great numbers of the larve just as
they are ready to quit the ovi-pouch, and think that we
could determine a sexual distinction, but we hesitate
to pronounce this with certainty, because it appeared
to us that both sexes were never developed in the same

DEVELOPMENT OF ANCEUS.

ANCEUS. ~ 77

ovi-pouch: the young of one animal appearing to be
all males, those of another being all females, so that
the variation may have been the result of an older or
younger stage of development.

But, however great the similarity may be between the
two sexes at the time of their first leaving the ovi-pouch
of the parent, they very soon exhibit a distinguishable
variation, as seen in the woodcut on the preceding page,
in which fig. 1 (of which 1a is an enlarged figure, seen
laterally) represents the male larva. That of the female
(figs. 2 and 2a, seen laterally) has the three posterior
segments of the pereion losing their crustaceous and seg-
mental character, and putting on that of a membranous
condition, and becoming fused together into one long
segment.

That of the male, as shown in fig. 1, of which la
is an enlarged representation (seen laterally), has the
segments well defined and crustaceous, but the central,
that is the third (though homologically the fifth), seg-
ment of the pereion, considerably increased in length,
with the coxe partially fused with the segment. Viewed
laterally, this segment is dorsally elevated above those

DEVELOPMENT OF ANCEUS.

Fig. a. Young of Anceus Edwardii (p. 201). Fig. 3. Eggs, Fig. oc. Young
of Anceus Maxillaris (pp. 176 and 192).

VOL. Il. N

178 ANCEID.

posterior to it. That we have not been misled into
accepting as parallel stages, conditions which are only
successive changes, as is stated by M. Hesse to be the
case, we:are assured, from the circumstance that we
have seen, and have in our possession, specimens of the
female from the smallest to the largest size ; and similar
ones of the male also, beginning, in each case, with

DEVELOPMENT OF ANCEUS.

This cut represents an animal, with its details, which agrees entirely
with Montagu’s figure of Praniza ceruleata, and which, notwithstanding its
large size, we presume must now be regarded as the fully developed larval form
of the female. (Praniza fuscata of Johnston, Oniscus marinus of Slabber,
Praniza ceruleata of Costa, Praniza maculata of Westwood, Praniza mau-
ritanica of Lucas, and Praniza Reinhardi of Kroyer, judging from the
figures given by these various authors, are animals in their larval condition,
whereas Praniza obesa of Lucas decidedly represents an adult ovigerous
female.) In the details given above are representations taken in different
points of view of the maxillipod (g), showing the varied positions of the ser-
rated portion ; the mandibles also (d) are much weaker than those organs
are represented either by Mr. Spence Bate (Annals N. H. s. 3, vol. ii. pl. 6),
or by M. Hesse.

ANCEUS. 179

animals scarcely a twentieth of an inch in length up
to nearly their full growth.

In the young or larval stage, the oral organs are similar
in both sexes. In fact the cephalon is much alike in
both, being subtriangular; the eyes lateral, placed at the
posterior angle of the cephalon, being somewhat larger
in the male than in the female. The superior antenne
are shorter than the inferior. The mandibles are an-
teriorly produced, and developed into sharp-pointed
instruments, with the inner margins acutely serrated,
the serrations being directed posteriorly. The maxille
are styliform and sharp; the inner margin of the first
pair is slightly serrated. The maxillipods are four-
jointed, and each joint supports a strong styliform spine,
and the whole of the oral appendages combine together
with a sharp process at the apex of the anterior lip, to
form a strong lanceolate organ, with which the animal
probably cuts its way through the skin of those fish on
which it preys.

Posterior to these appendages, near the inferior and
outer angle, stands, what we consider to be, the homo-
logue of one of the pairs of gnathopoda.

From analogy with TYanais, &c., in which the first
segment of the body is fused with the head, we should
infer that it is the first segment of the body in Anceus
which is fused with the head, whence the pair of appen-
dages in question would represent the anterior pair of
legs (or first pair of gnathopoda), but in Tanais, &c.,
the second segment of the body is distinct, and bears
a pair of legs, whilst in Anceus there is no trace either of
this second segment or second pair of legs, unless we
suppose the hind part of the head and the pair of appen-
dages in question to be the representatives of such
second segment and second pair of legs (in which case

N 2

180 ANCEIDA.,

there would be no trace of the anterior pair of legs).
In the young stages, this pair of appendages is long,
narrow, articulated, with a strong hook at the tip; but
in the adult state they become more or less dilated and
shortened in form, varying in the different species.

The character of the mouth does not appear to vary
until the animal has arrived at its adult stage.

We have not yet observed, neither has M. Hesse shown,
the way in which, and the period when, the male assumes
the large, projecting mandibles. We assume it to be at
the last stage between the young animal and the adult,
and that these organs are produced at a single moult;
though this is not in accordance with our experience of
the general development of this class of animals; but,
certainly, the adult stage is one of a retrograde character,
a circumstance that may account for its departure from
the usual or normal plan.

M. Hesse, in the 27th figure of his first plate, gives a
figure of a young animal in the act of moulting. He
describes it as a female, ‘‘ represented at the moment
when it undergoes its transformation, and while it is yet
enclosed within the skin of Praniza that it is about to
quit.” This, from our point of view, is merely the
development of a younger female into an older one.

We have in our collection a very similar specimen ;
it is that of a male, but we cannot perceive in the
enclosed animal the large mandibles characteristic of
the male adult Anceus. We also possess small specimens
of ‘the males, not more than two-thirds of the length
and half the breadth of the full-grown individuals of
this sex, and in which not only are the mandibles scarcely
more than one-fourth of the size of those of the latter,*.

* See woodeut in page 190: d representing one of the mandibles of the
full-grown male, and d@ d that of the smaller individual.

ANCEUS. 181

but the three posterior segments of the body are almost
as compactly soldered into a mass as in the females,
whilst the two large plates covering the mouth are fully
developed. These small males must, we should presume,
be subject to another moulting before arriving at the
fully developed state of the male sex, unless, indeed,
they are slightly developed specimens, such as are known
to occur in most cornuted species of animals. The female
is said to be parasitic in the young state, and to live in
crevices of the rocks when full grown. We believe that
this is the case also with the male, and that both males
and females change their oral organs with the final or
adult moulting.

The following remarks which we make on _ the
habits and structure of these animals are so much at
variance with the common notions concerning crusta-
ceous animals, so high in the class as those of this
genus, that we think it but just to ourselves to say,
that we have only arrived at them after close and
numerous dissections, and a long consideration of the
subject.

The females live parasitically on fish, burying their
heads almost to the eyes; and we repeat that we believe,
that up to the same period the male does also; but with
the adult moult the female quits the parasitic life for a
new kind of existence. With the adult moult the male
gets rid of the lanceolate oral appendages, and large, pro-
jecting mandibles are developed. We have some reason
to believe that the production of the great prehensile
mandibles of the male may be produced after the animal
has put on the adult form, since we have several speci-
mens in which these appendages are membranous, and
have not yet acquired their distinctive form. It may be,
however, that our specimens represent those which, by

182 ANCEID”®,

some accident, have lost the mandibles, which are now
undergoing reproduction.

_ The oral appendages of the female also undergo a great
change. As in the male, the lanceolate organs of the
mouth are lost; but, unlike the male, they are replaced
by no other appendages. Dissection shows us that they
have neither mandibles nor the anterior pair of maxille.
The only appendages which the female adult Anceus has
upon the oral surface of the cephalon, are the maxillipods
and a pair of gnathopoda, and even these are so depreciated
in character as to become rudimentary rather than nor-
mal appendages. The maxille consist of four gradually
diminishing joints, supported on a broad base that has
the antero-median angle produced to a blunt point. The
gnathopods are reduced to two or three joints, at the
base of which, on the internal surface, is a broad, exqui-
sitely thin, membranous scale.*

Still more remarkable, beneath these appendages there
appears to be neither mouth, stomach, nor alimentary
canal.

The immediate assumption of every carcinologist will
be that we may have mistaken exuvia, or cast skin, for the
animal. With the exuviz all the appendages, together
with the stomach and alimentary canal, are thrown off.

* This delicate membrane is unnoticed by Hesse and other previous
writers. _ It occurs only in the adult females, and is perfectly identical in its
character with the membrane forming the outer cover of the ovigerous sac.
If we suppose the large outer pair of appendages of the mouth of the female
to represent the second pair of Jegs or gnathopoda, we at once arrive at the
conclusion that this membrane is portion of the ovarian sac, which normally
exists in this position (see figure of Paranthura), and, indeed, in the females
of the Irish species it seemed to us, on dissection of several specimens, to be
actually continuous with the membrane within the first pair of true legs, and
to form, in fact, a jugular opening of the pouch, whence we extracted several
of the young, the antennz of one of which was actually inserted between this

pair of supposed gnathopods of the female. See the upper right hand figure
in page 190,

ANCEUS. 183

But we have not run the risk of such imputation, having
carefully examined the structure of the female before
the ova were developed, while they were in the ovisac,
and after the presence of embryos in the ovi-pouch; we
therefore think it possible that exceptions to a common
law may exist in this as well as in other things.

The ovi-pouch of this genus appears not formed by
a series of fine scales attached to the cox, as in the
Amphipoda, but by a thin membrane, that is itself the
wall of the ventral surface of the animal, which splits into
scales when the embryo is ready to take its departure.

M. Hesse states the period of incubation to be from
twenty to twenty-five days, and sometimes less, and he
believes that impregnation takes place prior to the last
or adult moult of the animal. This is contrary to our
anticipation, and, indeed, contrary to the common law of
nature. We have certainly dissected adult animals that
have not had the trace of ova. We therefore believe
that immediately after the animal has undergone the
adult moulting, it ceases from its gormandizing and com-
mences breeding, and that, consequently, impregnation
takes place immediately after the moult.

Observers must have noticed that in the younger stage
—that is, until the animal ceased to have a digestive ap-
paratus—the animal, by feeding, distends the posterior
portion of the pereion to a considerable extent, whence
M. Hesse says that “‘ sometimes they are so gorged with
blood that they become as distended as if they were full
of eggs.”

It must strike the physiologist as a remarkable circum-
stance, that the part which becomes distended by feeding
is not the stomach, which in crustacea exists in the
cephalon, but that part which afterwards becomes the
reservoir of the future progeny.

184 ANCEIDA.

In the earlier period of its parasitic life, the female
takes a green colour, which at a later stage deepens into
a bright blue. We speak of the common species round
our coast, to which Montagu gave the specific name of
ceruleata. M. Hesse has figured one of a brilliant red;
we have never seen such, but it is not improbable that
some species may change in their colour, which most pro-
bably varies with the condition of the food, for we have
taken them white, grey, green, blue, and brown.

An examination of the material confined within this
portion of the pereion shows it to consist of oil and fat
globules, and we have been able to determine that it is
intimately associated with the nourishment of the animal,
since by keeping them without food the coloured mass
decreases in size. It is such an animal that Mr. Spence
Bate figured in his paper ‘‘on Praniza and Anceus,”
** Annals Nat. Hist.” for Sept. 1858, where he observes,
«* After a few days the blue mass, which first appeared to
fill and distend the large segment of the pereion, gra-
dually diminished, apparently deteriorating. It recedes
first from the margin; in so doing it displays a series
of layers, placed one before the other, lying across the
animal. There were indications of these layers being
divided by cross sections. The relation that this co-
loured mass holds to that of the ova which, at a later
period, take its place, we know not; but we are inclined
to believe that it is a reservoir of fat on which the animal
is supported during the period of incubation.

We have not been fortunate enough to obtain em-
bryonic forms of the larve so young as those figured by
M. Hesse (plate 1, figs. 5, 6, and 7), which, by their
single central eye and general form, resemble the larvee
of some entomostracous species of crustacea, a form
that Dr. Fritz Miller contends, with some apparent show

ANCEUS., 185

of correctness, is the earliest stage in all crustaceous
life. The ova are proportionately very large, and the
parent retains the young after it has quitted the egg,
until the. young animal is scarcely less than half the
length of the parent. M. Hesse has figured a speci-
men, in which he has represented all the larve placed
within the ovi-pouch in a uniform manner, the head of
each being directed towards the centre of the pouch ;
this is not in accordance with our observations, as, of
the number of specimens that we have seen carrying
young, we have found all with the young creatures
variously placed, some with the head, others with the
tail, directed forwards or across. When the young quit
the care of the parent, nothing but a thin, transparent
skin remains, and the parent probably dies.

The male differs from the female by the presence of a
remarkable pair of mandibles directed forwards; fierce
and terrible organs of prehension they must be, but they
have always struck us as being organs that must be
valueless in assisting the animal in feeding. After we
had observed the structure of the oral organs of the
female, we directed our attention to those of the male.
In A. mazillaris,* on the under surface of the head, exists
a pair of large two-jointed plates, the basal being sub-
triangular and large, the other small and apical. From
its position and structure we consider this as the
representative of the hooked appendage in the young
animal, consequently the homologue of one of the pairs
of gnathopoda; beneath this lies a pair of foot-jaws, in
form very closely resembling those of the adult female.
On removing these, we arrive at a crustaceous surface,
with a minute and apparently imperforated tubercle in

* See the various details of the underside of the head and its organs
represented in p. 190,

186 ANCEIDA.

the middle. That the male animal should be without
a mouth and digestive apparatus, we certainly were not
prepared to find, since the presence of the mandibles,
though unusually placed, induced us to expect the
existence of a prima via as much as we had deduced
its absence, from finding those organs wanting in the
female.

The large lateral lobes of the cephalon are filled with
muscles, which hold and move the powerful mandibles
that can only exist as organs with which to grasp the
female.

From the facts which have now been observed, assisted
by the elaborate labours of M. Hesse, we have arrived at
the following conclusions :—

Ist. That Anceus of Risso and other authors, with
a large head and porrected mandibles, is the fully de-
veloped male state of this genus.

2nd. That Praniza of Leach and other authors, with a
small head, is the female state, either in an unimpregnated
or gravid state.

8rd. That the larva form of the animals of both sexes,
although closely resembling each other, may be distin-
guished at a very early stage of their growth, even if not
immediately after birth.

We hope that the conclusions at which we have thus
arrived will be tested by close observers. There are also
some points of interest in the internal structure of these
animals that have yet to be worked out.

ANCEUS MAXILLARIS. 187

TSOPODA. ANCEID.
ABERRANTIA.

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ANCEUS MAXILLARIS.

Specific character. Male with the cephalon broader than long, dorsally
depressed, especially in the middle and anterior part, and finely granulated
on each side within the eyes; fore margin transverse, with a prominent
tubercle within the mandibles, the centre itself having a much less prominent
conical tubercle. Mandibles about two-thirds of the length of the cephalon,
with a strong notch on the outer edge, and about ten denticulations on the
inner edge, the apex forming a sharp tooth. The second pair of gnathopoda
with the three or four basal segments soldered into a large flattened semioval
plate, strongly ciliated on the inner margin. Male exserted organ very long
and thin. Legs very finely serrated on the middle joints.

Female, with the second pair of gnathopoda strong, two-jointed, basal joint
angulated ; first pair of gnathopoda like those of the male.

Length of an inch.

(Male) Cancer maxillaris. Montagu, Trans. Linn. Soe. vii. p. 65,
t. 6, f. 2.
Gnathia maxillaris. Leacu, Enc. Brit. Suppl. Encycl. Méthod.
Crust. pl. 336, fig. 25.
Anceus maxillaris. Lamarck, Anim. sans. Vert. v. p. 168.

DesMAREST, Cons. Crust. p. 283,

138

ANCEID &.

t. 46, f. 6. Wuxstwoop, Annales Sci.
Nat. xxvii. p. 329. Mitnz Epwarps,
Crust. iii. p. 197. Wuutrs, B. M.
Cat. Brit. Crust. p. 74. Pop. Hist.
Brit. Crust. p. 2438, pl. xiii. f. 5.
Spence Barr, Ann. Nat. Hist. ser. 3,
vol. 2, pl. 7, f. 1, and details.

(Male) Gnathia termitoides. Leacu, Edin. Encye. vii. p. 402. -
Anceus rapax ? Mine Epwarps, Crust. iii. p. 196, t. 33,
f. 12. Régne Anim. Ed. Crochard
Crust. pl. 62, fig. 3.
Anceus scarites ? Hessr, Mém. trang. Acad. Sci. t. xviii.
D-1Di,, Plo; Ue glo.
(Female) Oniscus ceruleatus var. Montaau, Trans. Linn. Soc. xi. p. 16.
Praniza Montagui. Wustwoop, in Annales des Sci. Nat.
vol. xxvii. p. 327.
Praniza obesa ? Lucas, in Ann. Ent. Soc. France, 1849,
p. 465, pl. 15, £. 3.
(Immat.fem.) Oniscus ceruleatus. Montagu, Trans. Linn. Soc. xi. p. 15,

t. 4. f. 2. (Copied Ene. Méth.
Crust. pl. 339, £. 28, with the in-
correct name Oniscus (Celino, Leach)
thoracicus, Mont.).

Praniza ceruleata. Desmarust, Cons. Crust. p. 284, t. 46,
f. 8. Werstwoop, in Ann. Sci. Nat.
Xxvil. p. 326, t. 6, f. 5. MuItne
Epwarps, Crust. iii. p. 194, t. 33,
f. 10. Wuirr, B. M. Cat. Brit.
Crust. p. 74. Pop. Hist. Brit. Crust.
p. 240, pl. xiii. f. 4. Spence Barve,
Ann. Nat. Hist. ser. 3, vol. 2, pl. vi.
f. 4.

Gnathia termitoides. (Fem.?) Leacu, Edinb. Ene. vii. p. 402.

THE male of this species, figured in the preceding

page, is distinguished by the large size of the head, which,

together with the very prominent mandibular appendages,

gives the animal a fierce aspect. ‘The head is nearly

square, and about the size of the three anterior segments

of the body conjoined; it is slightly broader across the

middle, the eyes occupying the anterior lateral margins,

in front of which the head on each side is somewhat

squarely truncated, the antenne being affixed in front of

ANCEUS MAXILLARIS. 189

the antero-lateral angles thus formed: within the place
of insertion of the antennz on each side, the anterior
margin of the head is somewhat porrected, and trans-
verse, with a prominent tubercle on each side, the space
between these two tubercles being emarginate, with a
small prominence in the middle. The dorsal surface, of
the anterior half of the head, is depressed, an evident
channel running from the middle of the fore margin
to the centre of the head, where it meets with a small
posterior longitudinal carina, behind which is a very short
transverse ridge (which may indicate the point of union
of the two segments of the pereion soldered to the head).
On either side, arising from the inner margin of the eyes,
is a short slightly impressed fossa, the surface of which is
more or less strongly granulated. The superior antenne
are about the length of the mandibles, slender, with two
equal-sized basal joints, a longer third joint and a five-
jointed flagellum reaching to the tip of the fourth joint
of the lower antennz, which latter are nearly as long as
the head and rather thicker than the upper pair, with two
short basal joints ; a third and fourth joint, more robust
and of nearly equal length (equalling that of the third
joint of the upper pair), and a short flagellum of six
articuli. ‘The mandibles are of large size, being about
two-thirds of the length of the head. ‘They are nearly
flat above, of asomewhat elongate-triangular form, with a
prominent tooth in the middle of the outer edge, the apex
prolonged into a curved tooth, and the inner margin armed
with nine or ten small obtuse teeth; the inferior sur-
face of the head is protected by a pair of large flat valve-
like organs, each about half the size of the head itself
(and which might be supposed to represent the second pair
of enathopoda (2), corresponding with the second pair of
feet of the typical Isopods, but lettered g in the figures in

190 ANCEIDA.

the following cut). Each valve is somewhat of an oval
form, the outer edge nearly straight, fitting the somewhat
triangular deep impression on the underside of the head:
the inner margin of each valve is strongly ciliated, and

along the middle of the disc are three thickened circular
calcareous masses (apparently representing the ossified
centres of the three joints, of which this portion is pro-
bably composed). The somewhat pointed apex of each
of these valves is furnished with a minute joint, setose at
its tip. These valves are attached near the posterior
lateral angles of the head; they are ordinarily shut
together, their inner margins overlapping each other, so
as to form an under covering of the head. Within
them arises a much smaller and more delicate pair of
appendages (possibly homologous with the first pair of
gnathopoda) (A but marked f in the above figure),
composed of a somewhat square basal piece, with its

ANCEUS MAXTLLARIS. 191

inner apical angle produced into a slender elongated
process, followed by four joints attached together
obliquely, with a strong coating of bristles directed
obliquely backwards along their outer margin. ‘The first
and second free segments of the body are about the same
width as the head, short, transverse, with the sides rather
rounded and dilated; the three following segments are
somewhat narrowed, longer, much more irregular, and
less distinctly separated from each other than the anterior
segments, and with the lateral margins rounded and
directed somewhat backwards. ‘There is a small short
transverse piece in the middle between the last segment
of the body (pereion) and the first segment of the tail
(pleon). The pleon is about equal to two-thirds of the
length of the head, and consists of five transverse seg-
ments, followed by a triangular central terminal plate,
each segment being furnished on each side beneath with
two pairs of very delicate, strongly ciliated, branchial
scales. The tail (pleon) is not half the width of the
hind part of the body. The legs are of moderate length
and rather robust, with some small tubercles on the inner
margin of the middle joints.

The female, in its fully developed gravid state, as
represented in the following page, is a little longer than
the male, and has the body greatly swollen with eggs, or
young; the head, anterior segments of the body, and tail
being small, and marked all over with minute dark points.
The head is subtriangular, without any appearance of the
immense jaws of the male (of which, indeed, we have not
found the slightest vestige). The upper antenne are
small, and consist of a short basal joint, followed by two
nearly equal longer joints, and a short and slender ter-
minal flagellum. The lower antenne are much stronger
and longer than the upper, and consist of two strong

192 ANCEJDA.

basal joints followed by two longer ones, the fourth being
somewhat larger than the third, and followed by aslender
setose six-jointed flagellum. The inferior surface is
covered by two pairs of appendages (the gnathopoda),
the outer of which appears to consist of only two distinct
joints, although traces may be observed of their being
composed of several joints closely soldered together
(fig. g.@). The first of these joints is rather wide, flat-
tened, and considerably angulated beyond the middle, the
basal half being more curved and the distal half nearly
straight ; this is followed by an elongate-ovate joint,
setose at its extremity; and in certain positions we
perceived an indication of a very minute apical articu-
lation amongst the terminal setze. Within this pair of
appendages lies a pair of extremely delicate, flat mem-
branes, which we have above regarded as the anterior of
the incubatory scales, and within these are a second pair
of appendages (first pair of gnathopoda), similar in form

ANCEUS MAXILLARIS. 193

and articulation to those of the male. We have found no
other trace of mouth organs in these developed females.
The two succeeding segments of the body are quite dis-
tinct, very short, and rounded at the sides, but the three
terminal segments are consolidated into a large oval
mass covered with delicate membranes, through which
the eggs and young are plainly visible; the black eyes
of the latter giving to this part of the body a speckled
appearance, and showing at the same time that the
arrangement of the young within the incubatory pouch
is completely irregular; and we have never seen the sym-
metrical arrangement of the larvee as figured by M. Hesse
in the gravid female. The tail (pleon) and its appen-
-dages resemble those of the male, and the legs do not
exhibit any more marked differences beyond being some-
what more slender. One of the young extracted from
the pouch of the parent, and which attains to more than
a third the length of the adult animal before it quits the
ovi sac, is represented at the left hand side of the above
engraving.

The state of these animals previous to arriving at com-
plete maturity offers several circumstances sufficiently
remarkable to account for the larger sized larve (if
we may so term them) having been mistaken for fully
developed females. It is this .state which was_ first
described by Slabber and Montagu, and also by Mr.
Spence Bate, who confounded it with the adult animal, in
the “ Annals of Natural History ” for September, 1858.
The large mass formed by the consolidation of the three
posterior segments of the body is of a very elongated
oval shape, and in the individuals described by Montagu
was of a fine blue colour; whence the specific name
which he applied to it. It varies, however, not only in
different individuals, but also in different states of the

VOL. IL. )

194: ANCEIDA,

respective animals. We have received them of a bright
grass-green from Mr. Loughrin, of Polperro: blue from
the crevices in the slate in Plymouth Sound, and have
dredged them of an ash-grey, as well as transparent and
dirty white, in five or six fathoms of water in the same
locality.* ‘*The varieties of colour,” observes Mr.
Spence Bate, ‘‘appear to be dependent upon the pro-
gress made in the advancement towards spawning, or in
some way connected with the development of the ova.
When the animal is blue, I have observed a double line
of ova traversing the length of the enlarged segment.
This I presume to be the ovary, or oviduct, previous
to the escape of the ova into the incubatory pouch,
which they ultimately fill to the apparent annihilation
of the other contents of this part of the animal. I
have watched specimens in a glass, and have perceived,
after a few days, that the blue mass, which at first
appeared to fill and distend the large segment of the
pereion, gradually diminished. It recedes first from the
margin; in so doing it displays a series of layers placed
one before the other lying across the animal. There
were indications also of these layers being divided by
cross sections. The ova fill the pouch first, as seen in
fig. 6, and ultimately, as shown in fig. 8 (copied in
p- 177), where the embryo has considerably advanced
towards completion. The blue appearance is now
changed to brown—a circumstance that is due to the
reddish pigment cells which mark the pereion of the
young animal.” ‘Thus, at a period before the animal
has acquired its final condition, in which the suctorial
structure of the mouth is entirely lost, we find the ova
to be present, but probably impregnation does not take
place until the assumption of the final state.

* M. Hesse figures them also of a lemon colour, blood red, and sea-green.

ANCEUS MAXILLARIS. 195

We have no hesitation in referring the animals above
described to the Cancer mazillaris of Montagu. His
description is indeed very concise, and his figure very
rude, but an examination of the specimens preserved
in the British Museum Collection leave no doubt on
this point, all the males having the notch on the outer
edge of the mandibles, forming a small tooth.

Our specimens, moreover, have been found in con-
siderable numbers along the Devonshire coast, in Mon-
tagu’s localities. We are also able to state that Mr.
Montagu was acquainted with the fully developed female,
from an examination of his series of original drawings
now in the hands of Mr. Parfitt of Exeter; whence we
further learn that Montagu’s variety of his Oniscus
ceruleatus, having the body white, with the head,
pereion, and pleon maculated with yellow (which
Montagu shrewdly suggested might possibly be a sexual
variation), is a fully developed female. The name, there-
fore, of Praniza Montagui, which Professor Westwood
proposed for this variety, must sink into a synonym.

Mr. W. P. Cocks found the males in crevices of
rocks at extreme low-water mark at Gwyllyn Vase,
and in trawl refuse, whilst the Pranize he took most
abundantly in the neighbourhood of Falmouth, and a
specimen in the British Museum, labelled P. flavus,
Bantham, Falmouth, is undoubtedly a female of this
species. Montagu only obtained two specimens of his
Oniscus ceruleatus, which were found adhering to the body
of the Father lasher (Cottus scorpius) on the Devonshire
coast. The late Mr. W. Thompson’s collection also con-
tains specimens of the males found amongst dredged
matter at Bangor, in Ireland, in the month of August,
and also upon Bangor oysters in the month of December.
Mr. Norman also communicated to Professor Bell speci-

0 2

196 ANCEID®.

mens found on a stone brought up whilst haddock-fishing,
and females found upon a shell of Limitella communis.

Mr. Robertson has sent us both male and female speci-
mens from the Isle of Man, all taken under dead Balani.

We were at first disposed to regard our species as
identical with the Anceus manticora of M. Hesse’s
memoir; but the details which he has given of that
species do not agree with those which our specimens
present, and which, consequently, induce us to refer
the species rather to his Anceus Scarites, pl. iil. fig. 15 ;
although we have certainly never seen specimens ex-
hibiting the singular marking which he has represented :
the large patch in the centre of the three conjoined
segments of the body agrees, however, with the males
of our species, except that in the latter this patch is
only visible on the ventral surface. We believe, also,
that our species is identical with the Anceus rapax
of Milne Edwards,—as in fact that learned author has
suggested,—although in his figure he does not represent
the notch on the outer edge of the mandibles.

ANCEUS (PRANIZA) FUSCATA. 197

ee DOSES Uline Sy2 BiG hs:

ANCEUS (PRANIZA) FUSCATA.

Praniza fuscata. Jounston, in Mag. Nat. Hist. v. p. 520, f. 99. Wesrwoop,
in Ann. Sci. Nat. t. 27, pl. vi. f. 26. Wuuits, B. M.
Cat. Brit. Crust. p. 74. Pop. Hist. Brit. Crust. p. 241.

TueE late Dr. Johnston indicated, as a distinct species
of Praniza, certain individuals evidently in an imma-
ture condition, which he had taken on the Berwickshire
coast, and which, in the present state of our knowledge
of the species of this genus, it is impossible to assign
to the real mature representatives. They are described
as being two lines long, with the cephalon, two anterior
segments of the pereion, pleon, and legs colourless
and transparent, the eyes black, the large terminal con-
solidated mass of the pereion reddish-brown; the ce-
phalon is pointed, the antennae lateral, four-jointed,
the last joint long and divided by many transverse lines ;
the eyes lateral, large, and compound, like those of
insects. The pereion (which Johnston called the ab-
domen) is ovate, with a translucent edge and three pairs
of legs. The pleon is straight, six-jointed, the joints
equal, distinct, armed on the underside with four
rows of compressed fins, ciliated on the margins, and
the ultimate joint terminated besides with four similar
appendages, and a triangular process (the telson) between
them. The large pereion is in some specimens smooth

198 ANCEIDA.

and even, but in others (one of which had been selected
for the figure) it is raised at the top (or anterior part)
into two oval bosses, that greatly resemble the elytra
of a Meloe, and are beautifully punctured; the same
parts are apparent on the visible surface of both va-
rieties, but much smaller in that whose back is smooth.
Dr. Johnston suggested this to be a sexual distinction.

The following vignette, kindly drawn for us by Miss
Annie Wright, represents Balareadden Bay, Howth, near
which place Mr. Haliday obtained his specimens of this
genus,

BALARCADDEN BAY, HOWTH.

ANCEUS (PRANIZA) MACULATA, 199

ANCEUS (PRANIZA) MACULATA.

Praniza maculata. Wexstwoop, in Ann. Sci. Nat. xxvii. p. 326, t. 6, f. 4-25.
GuéxIn Méy., Icon. R. An. Crust. pl. 27, f. 10, a, b.
Mitne Epwarps, Crust. iii. p. 195. Wuuirtr, B. M.
Cat. Brit. Crust. p. 74,

UnpbeER the name of P. maculata, Professor Westwood
described, in his memoir on Praniza above referred to,
certain immature individuals belonging to the group,
which he had received in spirits from the Rev. F. W.
Hope, in company with various small parasitic crustacea,
collected on the coast of Shetland. These three spe-
cimens varied from one and a quarter to two lines in
length, and, with the exception of the large consolidated
hind pereionic mass, which was of a dark reddish-brown,
were of a brownish-white colour, with a row of brown
spots on each side of the five segments of the pleon, and
with various small dots of the same colour scattered
over the terminal segment. The largest and smallest
individual agreed together in having the hind portion
of the pereion of a texture identical with the rest of
the body, and distinctly divided into three segments,
of which the first was larger than the two others, whereas
the third individual, intermediate in its size, had this
portion of the body consolidated into a solid mass,
resembling hardened wax covered with a fine mem-
brane. The former individuals were considered to be
males, and the latter a female; a suggestion which
seems confirmed by what has been advanced in a pre-

200 ANCEIDA.

vious page. That all of them were in an immature
condition is evident from the careful analysis of the
mouth, published in the memoir in which their descrip-
tion appeared, and which, together with the relative
structures of the cephalon and pereion, and other cha-
racters, led Professor Westwood to consider that this
genus, and several others equally abnormal, ought
to form a distinct division, intermediate between the
Amphipoda and Isopoda (such, indeed, as Dana has
formed under the name of Anisopoda), displacing the
Lzmodipoda of Latreille (Caprellidze), from the osculant
situation which they had held in the classification pro-
posed by that author.

ANCEUS EDWARDII. 201

ISOPODA. ANCEID&.
ABERRANTIA.

ANCEUS EDWARDII.

Specific character. Female with the three posterior segments of the body
forming an elongate-ovate mass. Outer gnathopod minute, four-jointed,
inner gnathopod very large, five-jointed, the basal joint not produced into
a linear appendage at its inner angle, terminal joints densely ciliated on the
outside. :

Length, one-sixth of an inch.

Praniza Edwardit. Sprnocn Bats, in Annals Nat. Hist. ser. 3, vol. 21,
pl. vi. figs. 1, 2, and details.

Unpver this name have been described certain female
individuals belonging to this genus, which had cer-
tainly arrived at the adult state, as proved, not only
by the existence of fully developed larve within the
incubatory pouch, but also by the structure of the
mouth organs, which had entirely lost the suctorial form
of the immature condition. These females are of a
much narrower and more elongate form than the fully
developed females of either of the other species described
in this work. It is, in fact, owing to these animals being
in the fully developed state that they possess “ the more
continuous and less graceful outline from the anterior
part of the head to the posterior part of the pereion,”
which the author indicated as distinguishing these
animals from the full-grown larve of Praniza ceruleata.

202 ANCEIDA.

He also notices “the shortness of the pleon, and the
smallness and more equal size of the pereiopoda.” The
three organs on the right-hand side of the above wood-
cut represent first, to the left, the four-jointed outer foot-
jaw, of comparatively very small size, the basal joint
being large and curved, and the apical one very minute.
The middle, scale-like, exarticulate piece clearly repre-
sents the scale, which is the homotype of those belonging
to the incubatory pouch; and the large five-joint organ
to the right is one of the inner pair of the foot-jaws
which, in the female of A. mazillaris, is comparatively
very minute, and which we have failed to discover in
the female of A. Halidati. The organ represented on
the left side of our woodcut is the outer foot-jaw
seen in a different position, in which the minute apical
joint is not visible. These specimens were forwarded
from Banff by Mr. Edward, in whose honour they
were specifically named. One of them was charged
with young, and a figure of one of the larve extracted
from the incubatory pouch is represented in the left-
hand figure of the woodcut upon p. 177. “It is a
remarkable fact,” observes the author in introductory
remarks on the genus, ‘‘ that in the young the organs
generally bear a closer resemblance to those of P. c@ru-
leata than to those of their own parent species.” We
are now able to account for this remarkable fact, from
having learned that P. ceruleata, which we then con-
sidered as a distinct species in a fully developed con-
dition, is only a full-grown larva of the preceding
species.

Our knowledge of the present species must of course
be considered as imperfect until its legitimate male is
discovered.

ANCEUS HALIDATTI. 2038

ISOPODA., ANCEIDZ.
ABERRANTIA,

ANCEUS HALIDAII.

Specific character. Male, with the cephalon nearly square, the lateral
anterior angles truncated for the insertion of the antennz, middle of the fore
margin produced into three broad divisions, of which the central is slightly
porrected ; margin finely serrated ; antero-dorsal surface of cephalon very
broadly concave ; mandibles small, scarcely half the length of the cephalon,
entire on the outer margin; second pair of gnathopoda composed of five broad
joints. Male exserted organ rather short and thick; pereiopoda with small
spines on the terminal joints.

Female, with the outer gnathopoda five-jointed, narrower than in the
male; inner gnathopoda wanting?

Length, one quarter of an inch.

Anceus formica? Hussr, Mém. Etrang. Acad. Sci. t. xviii. p. 39, pl. iii.
figs. 5, 6, 7.

THIS species is at once distinguished from A. mawil-
laris by the very different structure and small size of
the mandibles and foot-jaws in the males, and by the
latter character as well as the (apparent) want of the
inner pair of foot-jaws in the females. The head of

204. ANCEIDA.

the male is somewhat quadrate in form, having the
anterior margin more prominent than in the preceding
species; the upper surface of the head is more broadly
and regularly concave, and the mandibles are scarcely
more than one-third of the length of the head; they are
curved, with the tip produced into a sharp tooth, below
which the inner margin is armed with about eight small,
sharp teeth. When shut, these mandibles project but a
small distance beyond the crenated fore margin of the
head. The antennz are about the length of the head, the
upper ones being shorter and considerably more slender
than the lower pair; the latter pair are composed of
two strong basal joints, followed by a third joint, rather
longer than the second; the fourth is still longer, rather
thickened at the tip, where it is armed with several
sete, and is followed by an eight-jointed flagellum.
The upper pair scarcely extends beyond the base of
the flagellum of the lower pair. The outer foot-jaws
are formed of a large basal joint, somewhat ovate-trun-
cate in form, affixed transversely by its base near the
posterior angles of the underside of the head; the re-
mainder of the organ consists of four joints, forming a
broad, somewhat oval, flattened mass, affixed so as to
form an angle on the basal joint; the first of these
four joints is small, and furnished with a strong seta
on its inner angle, whilst the remaining joints are
densely ciliated along the margin. ‘The inner pair of
foot-jaws differs considerably from the same organs in
A. mazxillaris, being formed of a large white, tumid, semi-
circular basal joint, having a small lobe at its inner
extremity, followed by four joints excessively delicate
and thin in their texture, and furnished on the outside
with long obliquely deflexed seta. The head is sepa-
rated from the first distinct segment of the body by a

ANCEUS HALIDAITI. 205

very short transverse ridge, and the two succeeding seg-
ments are much shorter than the three posterior, which
are irregular in the form of their lateral margins, the
posterior angles of each of which is produced into a
rounded lobe. The tail (pleon) is composed of six seg-
ments, of which the five anterior are furnished on each
side with a double scale, the outer division being narrower
than the inner, and terminated bya slender point, or short
strong seta, whilst the inner division is oval, slightly
ciliated at its margins, of a delicate transparent texture,
allowing the circulation to be seen within, and which is
carried round the organs within the lateral margins, as
indicated by the arrows in the accompanying figure ; the
tail is terminated by a small triangular joint, furnished
at each side with a pair of strongly ciliated, delicate
elongate-ovate plates. The legs are more robust than
in A. mavillaris, and have the terminal joints armed with
several small spines.

The female closely resembles that of A. mazillaris,
but is at once distinguished by the form of the outer
appendages of the mouth (the head of this sex is repre-
sented in the upper right-hand figure of the engraving
upon page 190). These organs are composed of five
joints, of which the basal one is the largest, and is
attached near the outer posterior angles of the underside
of the head in a transverse direction, the remaining
joints forming a somewhat oval flattened mass, of which
the first joint is small and transverse, the next larger and
semi-ovate, and the terminal joint very minute. We
have not been able to discover any trace of the inner
pair of foot-jaws.

This species was discovered by our friend Mr. Alex-
ander H. Haliday, and is referred to in a communication

dated October 9, 1847, which was published in the

206 ANCEIDA.

“Annals of Natural History ” (No. 5 for 1848, vol. i.
p- 65), in which he remarks: ‘I found a species of
Praniza, pretty common on the clayey shores of Strang-
ford Loch, last week in company with Anceus mazillaris
[t.e. the male of A. Halidau above described]. They
were in small cavities on the surface of the clay, under
stones, sometimes singly, oftener two, or even three
and four in each hole; the smaller slender green one;
were few in comparison. You will find some of the
new-born young with them having all the characteristic
form of the parent, but the posterior thoracic segments
not so completely confounded together.” Mr. Haliday
furnished us with living specimens of both sexes and
all sizes, captured at the end of February, 1856, amongst
which, however, the males preponderated in number, the
immature females being scarce at that period of the year,
whilst in the summer they bore a fair proportion to the
adult male, which was abundant enough. On the 14th
March following, he observed in a letter to us: ‘ It was
only the other day I observed the notice in the ‘ Comptes
rendus’ of the Paris Academy, of Hesse’s observations
on the identity of Anceus and Praniza. Notwith-
standing their constant association, and the fact that
the Anceus is always of pretty uniform size, and Pra-
niza varies from about the same down to the smallest
size, I should never have guessed that the latter was
the larva of the former, and yet do not understand
how to combine it with my positive observation of
Pramza producing young, the very eyes of which (be-
fore birth) were visible through the transparent integu-
ments of the parent.”

This Irish species appears at first sight most nearly
to approach the Anceus formica of M. Hesse’s memoir.
Our specimens, however, not only exhibit none of the

ANCEUS HALIDAII. 207

strongly defined coloration which his figures represent,
but the outer pair of foot-jaws in the male of that
species are formed of a large lunate exarticulate mass.
The only other species, A. brivatensis, which M. Hesse
describes as belonging to his first section (to which our
Irish species seems to be referable), differs in the much
broader head and in the strongly angulated sides of the
two anterior segments of the body. Moreover, his
figure of the underside of the male of A. brivatensis
shows the outer foot-jaws as of so small a size as not
closing the mouth, and “ formée d’une lame large ter-
minée & son extrémité par un petit appendice ovale
et cilié.”

In this indecision we have thought it more advisable
to propose for this Irish species the name of the gen-
tleman by whom it was discovered, and by whom so
many interesting additions, in different tribes of annulose
animals, have been discovered and most satisfactorily
investigated.

208 ISOPODA NORMALIA.

ISOPODA NORMALIA.

Tus group comprises the great majority of the order
which are distinguished by the nearly uniform size of
the seven segments which compose the pereion, as well as
of the seven pairs of legs attached to such segments.
The cephalon is always distinct; the branchial organs are
attached to the underside of the segments of the pleon,
being closely connected with the pleopoda, and lie
upon each other, being sometimes covered by a larger
outer pair, in the more normal forms.

The Isopoda normalia constitute two principal divi-
sions, founded upon the situation inhabited by the
animals of which they are composed ; the majority (Aqua-
spirantia) residing, either free or in a parasitic condition,
upon animals which live in the water, and consequently
breathing oxygen from the water in which they live;
whilst those of the other division (Aero-spirantia) reside
on the land, generally indeed in deep situations, and
breathe the free air by means of series of branchial
plates, probably assisted by spiracles with which the
branchiz are furnished.

ISOPODA. 209

Division—AQUASPIRANTIA.

THE animals composing this division are likewise
divisible into two tribes, according to the nature of
their habits and the situations in which they are conse-
quently found, being either 1. Parasttica, parasitic and
fixed on other aquatic animals, or, 2. Libecratica, tree,

and crawling or swimming about in the water.

Tribe—PARASITICA.

The first of these tribes comprises the species which
reside upon other crustaceans and fishes, and which may
conveniently be subdivided in the following manner :—

1. Those in which the sexes are greatly dissimilar in
form and size, and which are parasitic upon other crus-
taceous animals. Family—Bopyride.

2. Those in which the sexes are similar in general
form and size, which are found parasitic upon fishes, and
which are divisible into—

A. Those which have the base of the antennz concealed
beneath the porrected front of the head. Family—
Cymothoide (of which no representative has hitherto
been recorded as a native of our coasts).

B. Those which have the antenne naked or but slightly
covered at the base. Family—AHgide.

VOL. II. iP

210 BOPYRID®.

-

Fam.—BOPYRIDAE.

Tuis family (corresponding with the section Epicarides
of Latreille, and the Isopodes sedentaires of Milne Ed-
wards), although but of small extent, as to the number of
the species of which it is composed, exhibits some of
the most remarkable modifications of structure amongst
its different members, whilst the characters of the group
render it a very distinct one amongst the families of
which the order is composed. So far as hitherto ascer-
tained, the species are entirely parasitic upon the bodies
of other crustaceous animals, especially those of the
shrimp family and hermit crabs; species also of the
genera Galathea, Gebia, Gelasimus, and even of Mysis,
have been found to be infested by them.

The body, particularly of the female, is in most of the
species of a much less firm consistence than in the
majority of the order and in their full-grown condition,
there is a marvellous difference in the size of the two
sexes, the females being very large, ovate, or nearly cir-
cular in form, with the segments very indistinct, whilst
the males are very diminutive and elongated, with the
segments of the body quite distinct.*

In both sexes the antenne are very short, and more or
less rudimentary, consisting of only two or three joints
in the Bopyri, but with a more distinctly articulated
flagellum in some of the Phryazi. The mouth is very
rudimental, consisting in the female and probably in the

* In this respect these insects offer a marked analogy to the family Coccide
amongst hexapod insects. The female Cocci gradually lose their locomotive
organs and become inert animal masses, capable only of suction and deposi-
tion of eggs, with which the body seems entirely filled.

BOPYRIDX. 211

male also of a pair of mandibles deferentiated into a
pointed siphon-like organ, the two appendages meeting
together in a slight twist, and so strengthening each other
as a penetrating organ, which is protected by one or two
pairs of broad fleshy scale-like maxillz, of which the
first pair is generally bi- or tri-articulate, and the others
almost without trace of articulation, and united for the
most part to the under surface of the head by a small
joint.

The legs are very short, having a broad hand strongly
hooked at the tip for prehension; in some of the species
the full-grown females lose the greater portion of these
limbs. They are furnished with large incubatory plates
on the underside of the body: in some species, however,
they have the appearance of being recurved, and of
covering the upper side of the animal. (See Hesse, Ann.
Sci. Nat. ser. 5, t. il. p. 237, where this, and t. iv. p. 226,
where the reverse is stated to be the case.)

The tail (pleon) generally forms a distinct portion of
the animal, and is composed of a series of short segments,
which are often furnished with elongated lamelle, or other
analogous appendages, most conspicuous in the female.

The male is always very small, and much narrower
than the female, with the head and seven segments of
the body distinct, and each segment is furnished with a
pair of short legs formed like those of the female, but
more slender ; the tail (pleon) is also more elongated, with
the joints often distinct; the eyes are also distinct in
the males, although only rudimental or wanting in the
females.

The young of these animals are of an oval form, not
unlike that of a wood-louse, having the segments of the
tail of a comparatively larger size than in the adult state ;
in the typical genera they are furnished with two pairs of
antennee, of which the anterior are short, but the posterior

P2

ae BOPYRIDA.

pair are greatly elongated and furnished with very long ter-
minal sete, which are used as powerful organs of locomo-
tion; the legs are short, but strong and prehensile, and
the tail is furnished beneath, at the sides, with five pairs
of flattened, oval, ciliated appendages, those of the sixth or
last segment being elongated, and terminated by a pair
of slender styles, which are armed at the tips with long
seta. They are very active in this state. Whilst in the
character of the head, which projects beyond and above
the antennz, and in the form of the last three pairs of
legs, there is a close approximation to the larval form of
the parasitic Amphipoda forming the group Hyperina.

It hence appears that the earliest or larval con-
ditions of these parasites is their highest and most
advanced stage; the organs of sense and motion being
proportionately larger and better developed at that
period of their existence than ever after.

It would thus appear as if the nervous energy were
then greater, and that the growth of both males and
females is but, what Dana calls, a vegetative process, and
one that is destructive of cephalization, which decreases in
proportion to the growth of the animal. We therefore
argue that, of the adult Bopyri, the smaller male ought
to be taken as typical of the species rather than the
more abnormal female.*

The two families proposed by Mr. Milne Edwards,

* This principle seems, indeed, capable of extension, since wherever
amongst the Articulata an animal exhibits the sexual organs, or those which
more especially characterize the sex, in an unusual state of development, the
opposite sex is necessarily more decidedly typical of the group to which the
species belongs. Thus, among moths, the immensely pectinated antenna,
and the more decided shape of the wings of the males, render the females
better exponents of the groups to which they respectively belong than the
males; whereas in the genera Orgyia among the moths, Cebrio and Drilus
among beetles, Coccus among the Homoptera, in all which, for sexual pur-
poses, the wings remain undeveloped, and the body becomes dilated to an
enormous size filled with eggs, the opposite necessarily takes place.

BOPYRID®. 213

Bopyriens and Joniens, established upon the foliaceous or
filiform structure of the appendages of the tail, cannot
be maintained, as several genera have been lately dis-
covered which are truly Bopyrideous, although furnished
with filiform and even clavate caudal appendages. The
genera Prosthetes and Athelges, parasites on the tails of
hermit crabs (Paguri), are, in respect to the peculiar
formation of their pleonic appendages, amongst the most
remarkable of crustaceous animals. In Jone, these organs
are singularly branched, resembling pieces of coral, and
the incubatory plates are furnished with long clavate
appendages. We have added the anomalous parasitic
genus Liriope to this family (rather than place it near
Tanais, as done by Dana), from a consideration of its
general character. The entire want of limbs in the
female, and the somewhat indistinctly articulated body
of the males, with the pleon destitute of lateral terminal
appendages, are very characteristic distinctions, separating
it from the majority of the family, but, at the same
time, removing it still farther from the Tanaides. The
genus Cryptothir of Dana appears to us to be founded
upon a carelessly examined male of a species of Liriope,
as may be at once perceived by comparing Dana’s figure
of Crypt. minutum with our figure of Liriope pygmea.
The family, at first, comprised only the genus Bopyrus,
a separate family having been proposed for Jone, but
more recent observations have fully proved, as stated above,
not only that the two animals are closely united together
by the intervention of several genera discovered since the
publication of M. Milne Edwards’s general work on the
Crustacea, such as Kepon, Phryxus, and Athelges, &c., but
that the genera Gyge of Cornalia and Panceri, Dajus of
Kroyer, Ledya of Cornalia, and Argeia of Dana must be
added to the family.

214 BOPYRIDA.

ISOPODA. BOPYRIDA.
NORMALLIA.

Genus—BOPYRUS, LatreiLue.

THE male of this genus is very small, narrow, and
elongated, resembling an Jdotea in its general form, but
with only rudimentary antennz, and with the pleon
gradually narrowed to the tip and formed of six segments
fused together, except at the margin, and apparently
destitute of lateral appendages. The body is symme-
trical in its shape.

The cephalon is distinct, transversely ovate, and fur-
nished on the underside with two pairs of antenne, the
outer pair of which are composed of four short joints, ter-
minated by setz, whilst the inner pair are almost rudi-
mental, and composed apparently of only two joints ;
the mouth is also almost rudimental, forming a conical
point. The seven pairs of legs are of nearly equal size,
and of considerable strength and thickness; they are
affixed on the underside of the body, near the lateral
margins, which are prolonged into rounded plates, and
are directed, when at rest, towards the mesial line of
the body, and terminated by a broadly ovate recurved
hand, with a short, strong, bent claw at its extremity,
employed for prehension.

The female is five or six times as large again as the
male, being pear-shaped and unsymmetrical in its form,
generally curved to one or the other side, and very
much depressed, so that it assumes the appearance of a
shield, having the lateral margins rather dilated and
elevated, the lateral line of the segments being more

BOPYRUS. 215

continuous than in the male. The head also is immersed
in the anterior segment of the body, its front margin
forming a continuous curve with that of the body. The
antennee are even smaller and more rudimental than
those of the male, the outer pair being apparently
only three jointed, and the inner pair only two
jointed.

The mouth is comparatively rudimental in its structure,
and is nearly concealed by a pair of oval operculiform
foot-jaws, of which the anterior extremity is furnished
on its inner edge with a small flattened and biarticulate
appendage; beneath these foot-jaws and near their base
are several minute lobes; the lower lip, on the contrary,
is well developed, and forms with the labrum and man-
dibles a sort of conical sucker, the mandibles being
minute, pointed, and scarcely movable.

The pereion is broad and flat, and the seven segments
of which it is composed are closely soldered together,
the lateral portions forming a rather strong border,
beneath which are affixed the seven pairs of short,
strong, prehensible feet, resembling those of the male
in form. They are very small, so as not to extend
beyond the sides of the body, and each is furnished
at the base with a large plate-like appendage or valve,
generally folded inwards, so as to form an incubatory
pouch, which does not, however, entirely cover the central
part of the underside of the body, leaving a wide open
space, which allows the eggs and young to be seen; the
anterior of these plates differs in form from the rest, and
seems rather to be transformed into an appendage of the
mouth, having its lower extremity obtuse, free and
curved (fig. +).

The pleon in this sex is broad at the base, but
narrower than the pereion, and gradually decreases in

216 BOPYRIDZ.

breadth to its extremity, which is rounded, the six
segments of which it is composed having the lateral
margins thinner than those of the body; on the upper
side the articulations are almost obliterated, whilst its
lower surface is covered with five pairs of pleopoda, each
consisting of a single membranous plate of a somewhat
triangular form, the terminal segment being destitute of
any lateral appendage.

The genus Bopyrus was established by Latreille in one
of his earliest works, and was placed by him amongst the
Isopodous crustaceans, being, in the first edition of the
*“Réegne Animal,” placed at the end of the order,
with the view of showing what might be regarded
as its organic degradation as compared with the other
animals of the order. In the second edition of the same
work, however, Latreille placed the genus at the begin-
ning of the order, in a section termed Epicarides, with the
view of bringing it into close connection with the Cymo-
thoades, with which it has an evident affinity.

In 1772, M. Fougeroux de Bondaroy published a
memoir on B, squillarum,* in which he completely dis-
proved the old fallacy entertained by fishermen on the
coasts of France, that the Bopyri were the young of
soles or other flat fish which took shelter under the
shell of the prawn to protect them in the early state of
their existence—an idea which even Deslandes had held
and recorded in the Mémoires de l’Académie Royale des
Sciences de Paris in 1772.

In 1857 some interesting observations upon the genus
were published by Heinrich Rathke, “ De Bopyro’ et
Nereide. Rigze et Dorpati,” 4to; also in his work
on morphology, ‘‘ Reisebemerkungen aus Tamien.”

* Hist. de Acad. des Sciences, 1772, p. 29, t. 1.

BOPYRUS. dl IA

The females observed by him were five lines, and the
males a line and one-third long. The former were in-
variably found upon female prawns, of which he had
observed several hundreds thus infested, whilst quite as
many male prawns which he had observed were found to
be free from their attacks.

The mode of attachment of the parasites and the various
and peculiar species of crustacea on which they subsist is
worthy of some consideration.

They apparently work in pairs and only so, and from
the following isolated observation would seem to do so
from their earliest stages.

Some little time since, having been requested to
examine some crustacea brought home from Australia,
we found a shrimp (Caridina truncifrons*) laden with ova,
amongst which we perceived two specimens of the larva
of a Bopyroid crustacean, a circumstance that appears
to throw some light on the subject, by suggesting the
supposition that the larval Bopyri first take shelter among
the freely hanging ova previously to their finding their
way beneath the branchial walls of the carapace, and so
having quitted the care of their own parent, they are
fostered by another, on whom probably at a later period
they prey parasitically.

* Proc, Zool. Society, Nov. 24, 1863.

218 BOPYRIDA.

ISOPODA. BOPYRIDA,
NORMALIA,

BOPYRUS SQUILLARUM.

Specific character. Male. Narrow, with the sides of each segment of the
pereion produced into a flattened, rounded lobe. Pleon having the segments
confluent. Antenne concealed beneath the cephalon. :

Female. Unsymmetrical, dilated at the sides. Pereiopoda small, strong,
sub-equal. Anterior scales of the incubatory pouch curved, obtuse, and free.

Length of the male 1 line ; of the female 4 or 5 lines.

Bopyrus Squillarum. LaTREILLE, Hist. Nat. Crust. et
IER \abb 1h Ub Gh ie Y2.
Gen. Crust. et Ins. i. p. 67,
t. 2, f. 4. Lamarcr, Hist.
Anim. sans Vertebr. v. p. 164.
DrsMAREST, Cons. Crust. p.
325, pl. 49, f.8—14. GufRIn
Menev. Icon. R. Anim. Crust,
pl. 29, f. 2. Brutus, Exped.
Morée, p. 46. Montagu,
Trans, Linn. Soc. ix. 105

BOPYRUS SQUILLARUM. 219

(Oniscus sq.). GooDsIR, in
Ann. Nat. Hist. xi. p. 75, pl.
7. Mitne Epwarps, Crust.
iii, p. 282. Wurtx, Cat. Brit.
Crust. (Brit. Mus.) p. 82.
Pop. Hist. Brit. Crust. p. 256.
Monoculus Crangorum. Fasricius, Ent. Syst. Suppl. p.
306. Bosc, Hist. Crust. i.
216 (Bopyrus cr.).
Insecte qui s'attaché a la brevette. FoucEroux pg Bonparoy, Mém.
Acad. Se. 1772, p. 29, t. 1.
(Var.?) Bopyrus Palemonis. Risso, Crust. de Nice, p. 148.
LaMARCcK, Op. Cit. p. 165.
DrEsMAREST, Crust. p, 326.

Tuts species has long been known in consequence of
its occurrence, during the summer months, beneath the
carapace of the common edible prawn, the presence of
the female causing a large tumour, of nearly half an
inch in diameter, on the side where the parasite affixes
itself. The female, in the ordinary condition, is flat-
tened and broadly ovate in form, and the minute male is
generally to be found fixed amongst the respiratory
plates on the underside of the tail of the female. The
male closely resembles one of the Jdotee in miniature,
having the body elongate and narrow, with rounded,
flattened lobes at the sides of the segments of the body,
and with the tail of a reversed, triangular form, rounded
at the tip, with the six segments only indicated by five
incisions on each side, being confluent on the disc. The
antennze are very short, and resemble those of the
female, and the legs are also very short, although strong
and chelate.

The female is broadly ovate, but having the pleon
somewhat narrower than the pereion, flattened and
curved either to the right or left,* according to the side

* This curvature is occasioned by the unequal pressure from the carapace
of the prawn.

220 BOPYRID&.

of the prawn to which it has been affixed; hence, in our
right-hand figure, representing the dorsal view of the
female, the head is seen to the left of a straight line, the
lateral margins of the body to the right being distended,
whilst those of the opposite side are contracted in a
corresponding degree; the head itself does not project
beyond the general outline of the body, which is almost
continuous, and its anterior edge is rather sharp; the
hind part is considerably contracted, and very deeply
immersed in the anterior segment of the body; the eyes
are wanting in this sex. ‘The antennz are very small,
the outer pair being composed of three short, broad
joints, gradually diminishing in size, the last terminating
in a minute point, which may possibly represent the
flagellum ; the inner pair appear to be only formed of
two distinct joints, of which the basal one is nearly
circular.

The rudimental mouth is covered by a large pair of
foot-jaws (maxille), flattened, with the inner margin
(where the two meet together) nearly straight, the inner
apical angle being provided with a small, nearly circular,
lobe or joint, clothed with small hairs, and the base of
this pair of foot-jaws is furnished with two or three
membranous, flattened, pointed appendages. ‘The an-
terior pair of the scales forming the incubatory pouch
are transverse, and furnished with a large, flattened,
curved lobe, of which the extremity is obtuse and in-
curved. The other scales are affixed within the base of
the legs, the hinder extremity of each overlapping the
succeeding scale.

The seven pairs of legs are of equal size and similar
in form, being short and thick, having a broad, oval
hand, terminated by a small finger. They are generally
folded back and concealed beneath the lateral margins of

BOPYRUS SQUILLARUM. 221

the body. The respiratory scales on the underside of
the tail are short and transverse; the basal segment of
the tail is much shorter than the following, the second
and three succeeding being of equal size, whilst the
sixth is rather narrow and nearly truncate, without any
appendages.

The female when alive is of a pale greenish colour,
glossy above, with the head and oral plates black, and
those of the ovisac and under surface of the head black
or very dark at their edges.

The young Bopyri, before they leave the incubatory
pouch of the females, are ovate in form, and dorsally
convex, resembling very minute wood-lice, with the
outer pair of antennz greatly elongated, composed of
four joints, of which the first is short and robust, and
the others elongated and terminated by one or two very
long and slender setaz. The legs are broadly sub-cheli-
ferous, especially the four posterior pairs, the three
anterior pairs being rather more slender and directed
forwards, whilst the four latter pairs are directed back-
wards. The respiratory scales of the tail (pleopoda) are
strongly setigerous, the posterior pair being composed
of a very short basal joint, supporting two elongated
rami, pointed, and tipped with one or two terminal
sete.

The females of this species are attached to the outer
lining of the branchial cavity of the common prawn, a
single parasite being found upon an individual prawn. The
fecundity of these parasites is very great, the eggs being
retained within the incubatory pouch where they are
hatched, and M. Risso states that he had counted as
many as eight hundred young ones nourished by a single

female.
Mr. Adam White, upon the authority of Col. Mon-

222. BOPYRIDA.

tagu, states that this species is common also under the
carapace of the shrimp. It has not been our experience
to meet with one, those that we have seen being obtained
from prawns. From Guernsey and Jersey we have re-
ceived them from the Rev. A. M. Norman, on Palemon
serratus and Palemon Leachii, and from Polperro, where
Mr. Loughrin has found them on Palemon serratus.

The late Harry Goodsir published figures of a species
of this genus, which he names B. Squillarum, representing
the male, female, and young, which he had obtained
from the carapace of a new species of Hippolyte (H. ensi-
ferus) found in the gulf-weed between 25° and 30° north,
and 40° west longitude. His figures, unfortunately, do
not show sufficient care in their delineation, the seg-
mentation of the body of the female being unintel-
ligible, whilst the figures of the ambulatory legs of
both sexes differ so materially from those organs in our
English specimens, as to lead us to suppose that they
cannot belong to this genus, but either to Bopyroides
of Stimpson, or to Gyge.

BOPYRID #. 223

ISOPODA. BOPYRID.
NORMALTIA.

Genus—GYGE, CorNaLiA AND PANCERI.

Mem. Acad. Reale di Torino, Ser. 2, t. 19 (1861), p. 85.

Male. Cephalon as broad as first segment of the pereion.
Pereion long and narrow, segments subequal in length. Pleon
short and broad, segments distinct and subequal in length with
those of the pereion. Eyes small and situated at the posterior
part of the cephalon; second pair of antennze well developed.

Female. Oval, anteriorly slightly unsymmetrical. Pereion,
having the segments subequal, except the first two. Pleon having
the segments distinct and subequal with those of the pereion.
Antenne rudimentary. Branchial appendages consisting of a
series of small single sacs attached within the ventral lateral .
extremity of the several segments of the pleon, and a series of
transverse folds between them. Posterior pair of pleopoda
slightly developed.

Tuls genus is certainly near Bopyrus, but differs from
it in important structural conditions. It must also be
very closely allied to the genus Bopyroides of Stimpson,
which that author has formed for those species that
agree in shape and structure with Bopyrus, but differ in
their branchial features, in having “ merely fleshy ridges
instead of lamine.”

From the female Bopyrus and therefore also from Bopy-
roides this genus differs in shape, being roundly oval, and
not having the pleon narrower than the pereion; moreover,
in this genus the segments are distinct, in which it coin-
cides with Stimpson’s description of Bopyroides, whereas
in Bopyrus they are all fused together in the central
dorsal axis. Bopyrus, also, is unsymmetrical throughout,

224 BOPYRIDA.

whereas Gyge is only so at the anterior portion of the
animal.

It also differs in the more rudimentary condition of
both pairs of antennz, and in the larger development of
the ovigerous plates.

The male is in proportion much larger, being nearly one-
half the length of the female. It has also the cephalon
proportionately larger, and the antenne, particularly those
of the second pair, largely developed. The segments of
the pleon are distinct, anteriorly being nearly as large as
those of the pereion, and decreasing in length and breadth
posteriorly very rapidly ; whereas in Bopyrus they are
fused together except at the margins, smaller than those
of the pereion, and decrease gradually.

The larve of this genus appear to correspond very
closely with those of Bopyrus, but appear to have the
antenne laterally nearer to one another.

BOPYRIDA. 995

ISOPODA. BOPYRIDA.
NORMALLA.

GYGE GALATHE#.

Male.—Cephalon roundish, neariy as broad as the first segment of the
pereion. Pereion increasing in breadth posteriorly. Pleon decreasing in
breadth posteriorly, last segment bifurcate. First pair of antenne short,
three-jointed ; second pair about three times the length of the superior, and
terminating in a small flagellum.

Female.—Flat, oval, slightly unsymmetrical. Cephalon broad, pleon short
and continuous with the pereion, terminal segment having a pair of pleo-
poda (posterior pair) projecting beyond its extremity and giving a bifurcate
appearance to the posterior margin. Antenne rudimentary. Branchial
appendages consisting of small sacs near the margin of the ventral surface
of each segment of the pleon.

Length of the male, three-twentieths of an inch.

se 5 female, eight-twentieths ,,

Tue male gradually increases in breadth from the head
to the last segment of the body (pereion), from which the
segments of the tail rapidly decrease, thus giving the
general aspect of a long narrow animal, with a large round

VOL. Il. Q

296 GYGE GALATHE,

flat tail, which is the broadest part of it. The head is very
nearly circular, flattened slightly at the anterior margin and
cut off posteriorly by the first segment of the body, but
still forming more than a semicircle. ‘The first segment of
the body is as long as and scarcely broader than the head ;
the lateral margins are square. The six following segments
are of the same length as the first, but gradually increase
in breadth and become more and more pointed at the lateral
margins, as they proceed towards the posterior extremity.
The first segment of the pleon is somewhat less in length
and breadth than the last of the pereion. The remain-
ing segments decrease until the fifth, which is very small,
and forms with the sixth a small forked extremity.

The eyes are small, irregular patches of black pigment
situated near the latero-posterior angles of the head.
The first antenne are small, and scarcely reach to the
anterior margin of the head; they consist of two joints,
each as broad as long, and a third that is much smaller
and tipped with cilia. The second pair of antenne are
nearly three times as long as the first, and project beyond
the lateral margins a considerable distance ; they consist
of five joints, and a minute triarticulated flagellum. The
first three joints are subequal in length and diameter, the
fourth is narrower and longer than the preceding, the
fifth is still narrower and short, and appears to form the
basal part of the small triarticulated flagellum, which
supports, as well as the three preceding joints, a few short
hairs. The organs of the mouth form a central conical
process, but they have not been dissected out. The first
pair of feet (first pair of gnathopoda) are large, strong
and subchelate, the palm is concave, and the long curved
dactylos impinges by the apex only against the dental
projection of the posterior angle of the palm. The
second and succeeding pairs of limbs gradually but

GYGE GALATHEF. par eyt

considerably decrease in the dimensions of the prehensile
portion, and have the palm somewhat convex and
serrated, the dactylos short and thick. There appears to
be no distinct pleopoda or branchial appendages of any
kind, but the thin lateral extremity of each segment
appears to be considerably attenuated and to be traversed
by numerous channels, which must necessarily assist very
considerably in bringing the vital fluids into close approx-
imation with the oxidizing influence of the water.

The female is oval, broad, but little more than half as
long again as the male. Anterior portion of the animal
only, unsymmetrical. Head partially fused with the first
segment of the body, first segment short, the second
scarcely longer, the five posterior segments subequal, longer
than the first two. Those of the tail (pleon) gradually
decrease until the sixth, which terminates in a small
forked extremity, being the rudimentary condition of the
posterior pair of pleopoda, which are so largely developed
in the larval condition.

The eyes are wanting. The antennze are rudimentary,
each pair consisting of a single basal joint, not longer
than broad, and an apical small spine or second joint.
The oral organs converge to a point, and are situated
below and between the antennze; these are covered and
protected by the maxillz, and the oral appendages deve-
loped in the form of large fleshy scales, somewhat similar
to but thicker than the ovigerous plates that spring from
the base of every leg.

The pleopoda or branchial appendages consist of small
sacs attached close to the under surface near the extremity
of each segment, while a membranous ridge or fold
reaches from one extremity to the other.

The young animal as it appears when just able to quit
the parental pouch, is dorsally arcuate, the cephalon

a2

228 GYGE GALATHEA.

anteriorly broad and projecting hood-like over the an-
tenn. The segments of the pereion are all present as
well as those of the pleon, with which they are subequal,
the last segment terminating in a central tubular
process, the extremity probably of the alimentary
canal. (See the upper right-hand figure.)

The eyes are small, irregular blotches, situated within
the lateral and near the posterior margin of the cephalon.
The first pair of antennz are rudimentary, consisting
of a basal joint of tolerably large proportions, and a ter-
minal triarticulate flagellum. The second pair are more
than half the length of the animal, and consist of three
(or four ?) large joints and a terminal slender one tipped
with four hairs, one of which is very long and strong and
two very short. The four anterior pairs of legs have the
propodos round and the dactylos short and curved, the
three posterior pairs have the propodos long, narrow, and
the dactylos straight. The last two differ from the ante-
penultimate in having the carpus produced along the
inferior margin of the propodos to the posterior angle
of the palm. The pleopoda are five pairs, and consist
of a series of foliaceous plates tipped with an external
long and an internal short hair. The posterior pair of
pleopoda are biramous, each branch being biarticulate,
terminating in a fine hair-like point.

‘The specimens from which these descriptions are taken
were procured by the Rev. A. M. Norman at Herm, in
Guernsey, on a specimen of Galathea squamifera.

With the exception of a difference in the habits of the
species, the one above described seems (so far as we are
able to judge from the description and figures of both
sexes, given by Messrs. Cornalia and Panzeri in their
elaborate memoir above referred to of G. branchial,
which infests Gebia Venetiarum and littoralis), scarcely

GYGE GALATHER. 229

to differ from the Italian animal, agreeing therewith,
especially in the peculiar form of the male.

The following vignette of the Cliffs of Whitenore, in
Weymouth Bay, has been kindly sent to us for this
work by Mr. Thompson, of Weymouth.

CLIFFS AT WHITENORE, WEYMOUTH BAY.

230 BOPYRIDA.

ISOPODA. BOPYRIDA.
NORM ALLA,

GYGE HIPPOLYTES.

Male.—Sides subparallel ; antennz, advanced beyond the front of the head;
segments of the pleon fused into an elongated ovate mass, obtuse at the
extremity,

Female.—Broadly ovate, depressed, anterior portion slightly curved towards
the left (when viewed dorsally) ; segments of the pereion and pleon distinct,
sub-continuous ; terminal segment apparently notched at the tip, owing to
the projection of the posterior pair of pleopoda.

Length :—Female, seven-twentieths of an inch.

Bopyrus Hippolytes. Kroyer, Grénlands Amfipoder Besck, p. 78, pl. 4,
fig. 22. Mrtne Epwarps, Crust. 3, 283. Wuirr,
Pop. Hist. Brit. Crust. p. 256.

Tue male of this species is narrow, with the sides of
the body almost parallel ; the head transversely ovate, with
minute eyes and with the four antennz short, conical,
subequal, and advanced beyond the front margin of the
head; the segments of the body are rather wide apart at
the sides, and those of the tail are confluent, forming an

GYGE HIPPOLYTES. Zoe

apparently inarticulate mass of an elongate ovate form,
somewhat truncated at the base, scarcely with indications
of divisions between the joints, the extremity being entire.

The female is broadly ovate, with the body slightly
curved towards the left, the segments distinct, especially
those of the tail, which is terminated by a small joint
notched at its extremity, two minute pleopoda of an elon-
gate-ovate form arising on its underside and having their
ends visible within the emargination of the joint.

The head is broad, furnished on its underside with two
pairs of minute conical antenne, the inner pair consisting
of three, and the outer pair of four joints, the penulti-
mate of which is slightly setose, and the last terminated
by a minute fascicle of sete; the seven pairs of feet are
small but robust, and of uniform size and shape, termi-
nated by an elongate-ovate hand with a minute but
strongly hooked finger; the two preceding joints being
rather rugose at their extremities on the underside.

This species was first described by Kroyer, who de-
tected it as a parasite on a species of prawn of the
genus Hippolyte (H1. polaris).

A specimen of this species is recorded as having been
taken by the late Mr. W. Thompson, of Belfast, on the
coast of Galway. The specimen belongs to the Belfast
Museum, and is, unfortunately in a damaged condition.

Another specimen (of the female), which appears to
us to belong to the same species, and which has supplied
the central figure in the above woodcut, was forwarded to
us from Polperro by Mr. Loughrin ; our two lower-side
figures being copied from Kroyer’s figures of the male
and underside of the female.

Jac BOPYRID.

ISOPODA, BOP YRIDA.
NORMALLA.

Genus—PHRYXUS, RaruKke.
(Phryzus and Pleurocrypta, Hesse.)

THIs genus was instituted by Rathke, for the reception
of a species of the Bopyride, parasitic on a prawn of the
genus Hippolyte, remarkable for the very swollen and
unsymmetrical form of the female, of which the legs on
one side are nearly abortive in the full-grown state,
but more especially for the large size of the lobes or
plate-like branchial appendages of the tail, by which it
at once differs from the two preceding genera.

The whole of the species hitherto discovered, including
three new ones now first made known to the public, are
parasites on various crustaceous animals belonging to the
Anomourous and Macrourous divisions, including not
only the more typical Hippolyte, but also the aberrant
genera Pagurus and Galathea.

The male in the species which served for the establish-
ment of the genus is very minute and elongated in form,
with the head transversely ovate, with two minute dark
points indicating the eyes; the upper antenne are very
minute, and consist of three joints of equal length, but
gradually becoming more slender to the tip, which is
furnished with a number of hairs ; the lower antenne are
much longer, and consist of eight joints, also gradually
attenuated to the tip. The mouth is transformed into a
small conical protuberance rising from a semicircular
space. The pereion is composed of seven segments
of nearly equal size, each with the sides rounded and
wide apart (in specimens distended from having been

PHRYXUS. Dao

immersed in spirits), hence the body is nearly parallel at
the sides.

Each segment bears a pair of rather strong legs, formed
for walking, terminated by asemi-ovate hand, with a sharp
hook-like finger.

The pleon forms a subconic-ovate mass, with all the
segments closely soldered together, indicated more or less
distinctly by lateral incisions.

The full-grown female is a large inert nearly globular
mass, with the segments scarcely indicated by depressions, -
and with a series of wide and broad ovigerous plates,
which fold backwards and envelop the upper-side of the
body.

The cephaion is furnished with very short antenne,
resembling those of the male in structure, and the mouth
forms a large conical tubercle rounded at the extremity.

The pereiopoda are inclined towards the back, and
formed as in the female Bopyri, with the articulations
much less distinct than in the males, and the propoda are
small and weak, with a small curved obtuse dactylos.
These limbs are irregular in size on the two sides of the
body, some of them being even obsolete on one or other
side.

The pleon is composed of small joints, furnished with
elongated lobes or plates for breathing, varying in number
and size in the different species, the terminal joint being
small and bifid in the typical species.

We have added to the genus several species, the females
of which possess more or less elongated appendages to
the segments of the tail, but differ from the typical
species in having the body in the same sex symmetrical,
or nearly so; on this account one of these species has
been formed by M. Hesse into the genus Pleurocrypta,
which we have not thought necessary to retain.

234 BOPYRIDA.

TSOPODA. BOP YRIDA.
NORMALLA.

PHRYXUS ABDOMINALIS.

Male.—Upper antennz very short, three-jointed; second antenne eight-
jointed, gradually attenuated to the tip. Oblong, subdepressed, with the
pleon produced into a short blunt point.

Female.—Subglobose, very unsymmetrical, with the pereipoda on one side
of the body almost obsolete. Pleon furnished on each side with four large
oblong-ovate fleshy lobes ; terminal segment minute.

Length of male, one-tenth, of female, one-quarter, of an inch.

Bopyrus abdominalis. Kroyer, Natur. hist. Tidsk. iii. p. 102—, 289, pl. 1, 2
(1840); Voy. Scandinav. Crust. pl. 29, fig. 1.

Phryxus Hippolytes. Ratuxe, in Nova Acta Acad., Nat. Curios., xx. p. 40,
tab. 2. figs. 1—10. Wurrs, Pop. Hist. Brit. Crust.
fig. 257, pl. xiv. fig. a, male; b, female (1848).

Tue male of this species is extremely minute, and is
generally to be found partially immersed between the folds
of the posterior part of the body of the female. The

head is transversely ovate, with both pairs of antennz
visible in front.

PHRYXUS ABDOMINALIS. 235

The mouth in the full-grown male, in which probably
but little food is taken, is reduced to a small conical fleshy
lobe on the underside of the head.

The seven segments of the body are quite distinct, and
the seven pairs of legs are affixed near the sides of the
body beneath, and may be extended considerably beyond
the sides, although generally hidden by being folded
inwards close to the sides when at rest.

The tail forms a subconical piece, having all its seg-
ments closely soldered together with very slight indica-
tions of the articulations.

The female, when full-grown and distended with eggs
(of which the number is immense), forms a large, nearly
globular, mass, with one side of the body swollen to such
a degree that it extends far beyond the limits of the
head, absorbing the legs on this side, with the exception of
the most anterior. This is exhibited in the lower figure on
the left-hand side of our woodcut, where the mouth is in-
dicated by the small dark-shaded portion resting ona
somewhat heart-shaped base, having a leg with a dilated
basal joint on either side, that of the right side succeeded
by a series of folds, within which are attached the bases
of the succeeding legs, whereas those of the left side are
obsolete. These legs are slender, and terminated by an
oval hand with a weak and curved finger, obtuse at
its tip.

The sides of the body of the female are provided with
very large scales, not arranged in pairs, and which fall
backwards so as to cover the body.

The tail consists of five segments, of which the four
basal ones are short and narrow, having on either sidea
large and a small fleshy lobe of an oval shape, but varying
in size according to the side of the body to which they
are attached; being the largest on the dilated side. The

236 PHRYXUS HIPPOLYTES.

terminal segment is minute, and unfurnished with ap-
pendages. In Rathke’s dorsal figure of the species this
segment is represented as bifid, but in the ventral one as
entire, as appears also to be the case in our individuals.
We have no hesitation in regarding our specimens as
identical with Bopyrus abdominalis, elaborately figured in
all its details by Kroyer in 1840, which is represented by
him as attached to the under surface of the pereion of a
species of Prawn.

The young of this animal is oval and very convex, with
very slight indications of articulations ; the head is large,
with two dark round spots indicating the eyes; the upper
antennz are short and apparently exarticulate, whilst the
lower pair of antennz are about half the length of the
body and six-jointed, with a pencil of terminal hairs.
The body is furnished beneath with six pairs of strong
subcheliferous legs, and the hinder part of the body, re-
presenting the tail, is provided with five pairs of flattened
elongate-ovate plates, strongly ciliated at their extremi-
ties, the small obtusely triangular terminal segment being,
moreover, furnished on each side with a larger curved
lobe, bisetigerous at its tip.

This species was first detected by Herr Rathke asa
parasite beneath the shell of a species of Hippolyte. We
are indebted for our knowledge of it as a British species
to Mr. Frederick Bond, an excellent ornithologist and
entomologist, who obtained both sexes from the underside
of the tail of the white Shrimp of the Sussex Coast,
Pandalus annulicornis, in the month of April, 1846.

Mr. Alder has also obligingly forwarded to us a spe-
cimen of the male on Hippolyte Barleei, taken at Culler-
coats, on the Northumberland Coast. So firmly was the
little parasite attached to the ventral surface of the
pereion between the fifth pair of pereiopoda, that it was

PHRYXUS ABDOMINALIS. 237

necessary to remove the creature with an instrument.
This abnormal position was evidently one of some
duration, for there had been no female attached to the
Hippolyte, and the parasite, instead of being white and
bleached as these creatures generally are, was of a reddish
brown, and of hard structure.

The following vignette is a sketch of the Bay of
Bayndie, near Banff, taken by Mr. Greig from the
Elfkirk.

It is in this bay that many of the observations on the
Crustacea were made for us by Mr. Edward, to whom we
are indebted for the next species.

BAY OF BAYNDIE, BANFF ; FROM THE ELFKIRK.

238 BOPYRID®.

TSOPODA. BOPYRID &.
NORMALIA.

PHRYXUS FUSTICAUDATUS.

Female.—Oval, nearly symmetrical, the segments of the pereion clearly
indicated by lateral incisions; antennw, prominently seen beyond the fore
margin of the head ; pereiopoda swollen, with indistinct segments terminated
by a small claw with a minute dactylos. Pleon well defined, composed of
four segments narrower than those of the pereion, and furnished at the
sides with four clongate-clavate simple lobes ; terminal segment forming an
elongate-oval mass.

Length, one-tenth of an inch.

THE small but increasing size of the few specimens of
this species which we have hitherto seen, all of which are
females, their symmetrical form, and the want of develop-
ment of the scales in which the eggs are enveloped, lead us
to suppose that the individuals before us are not yet arrived
at the full growth. The curious lateral appendages at the
sides of the tail are more strongly developed than in any
other species we have yet seen, and their number agrees
with that of the same organs in Ph. Hippolytes.

PHRYXUS FUSTICAUDATUS. 239

The head is broadly semicircular in form, the middle
of the anterior margin produced into a conical lobe repre-
senting the organs of the mouth, at the sides of which are
affixed the two pairs of antennz, varying in length as
above described in the characters of the genus.

The body is oval, with the sides symmetrical, the seg-
ments well marked by incisions, with the sides of the
segments themselves rounded ; on the underside the seven
pairs of swollen obtuse feet are affixed, near the sides of
the body, each being terminated by a small claw with a
minute obtuse finger. The four basal segments of the
tail are very much narrower than those of the body, and
become gradually narrowed to the fifth or terminal joint,
which forms a large clavate mass ; the sides of each of the
four basal segments of the tail are furnished with a pair
of elongated clavate appendages for breathing.

We have only seen three specimens of this species,
which were discovered by our valued correspondent,
Mr. Edward, of Banff, attached to the branchie of the
common Soldier Crab, Pagurus Bernhardus, on the 12th

December, 1864.

240 BOPYRID®.

ISOPODA. BOPYRID.
NORMALIA.

PHRYXUS PAGURI.

Male.—With the cephalon nearly as broad as the joints of the pereion,
with two minute eyes. Antenne and pereiopoda not porrected in the front
or extending beyond the sides of the body. Pleon narrower than the pereion,
having the three anterior segments indistinctly defined.

Female.—Broadly ovate, nearly symmetrical, with very large ovigerous
scales. Pereiopoda robust, of considerable size, equally developed on each
side of the body. Pleon with the four anterior segments defined ; each
provided on each side with a pair of subglobose lobes attached by short
foot-stalks to a common slender base.

Length of the male, one-eighth of an inch ; of the female, nearly half an
inch.

Phrycus Paguri. Raruxn, in Nova Acta Acad., Nat. Curios., xx. p. 57,
tab. 1, figs. 18-15, male ; tab. 2, figs. 11,12, female.

Our figures of this species are copied from a very
careful series of drawings, made by our friend Mr. Robert
Templeton, from specimens taken from a Pagurus, dredged
off Bird Island, Strangford Lough, in from eight to ten
fathoms deep, with a muddy and shelly bottom, by Mr.

PHRYXUS PAGURI. 241

G. C. Hyndman, August 16, 1848, corrected by an ex-
amination of Mr. Templeton’s specimens.

The male is very minute, elongate-ovate, with the tail
more slender and indistinctly articulated. In Rathke’s
figure, the segments of the body are represented as
much more widely separated from each other at the sides
than in our specimen, the anterior lateral angle of each
segment being rounded, and the middle of the hinder
margin more rounded behind; the upper antenne are
very minute and three-jointed, the lower pair are longer,
and seen beyond the lateral margin of the head; the legs
are small, terminated by a small ovate hand with a minute
hook-like finger (dactylos).

The female is large and unwieldy, with very large
ovigerous scales. ‘The body is but slightly unsymmetrical,
nearly oval in form, with the ovigerous scales very large
and thrown over the back, entirely concealing the body,
limbs, and tail of the animal, where the latter is incurved ;
the head is oval, with the inner antenne very small, com-
posed of a thick basal joint and a minute terminal one ;
the outer pair are much larger, apparently three-jointed,
terminated by athin bristle. The legs are well developed
on each side of the body; they are strong and terminated
by an oval hand, having a minute emargination for the
reception of a small finger. The tail is composed of
four transverse segments, each furnished on each side
with a pair of nearly globose lobes, fixed by short
footstalks to a short and slender base, The tail is termi-
nated by a small joint supporting a single lobe like the
rest, so that there are seventeen of these appendages in
all.

Our figures represent the upper and under sides of the
female, with the head, one of the feet, and a pair of the
lobes of the tail, and the minute and slender male.

VOL. II. R

242 BOPYRIDA,

In addition to Mr. Templeton’s specimens, we have
received the male and female of this species from Pol-
perro, collected by Mr. Couch, as well as a coloured
drawing of a specimen which we also consider to belong
to this species from St. Andrews; having been taken by
Mr. McIntosh. It was first found by Rathke upon
Pagurus Bernhardus on the Norwegian shore.

Athelgue fullode of M. Hesse, Ann. Sc. Nat., ser. 4,
vol. xv. p. 97, pl. 9, appears to us to belong to this
species.

With reference to the question how the Bopyrus can
survive when the crab throws off its exuvium, Dr. Fritz
Miller writes to us—“* When the crab casts its skin,
there can be no doubt but that the Bopyrus must go
along with it; but as the crab, immediately after exuvia-
tion, is in an almost helpless and motionless condition, I
think that the Bopyrus may crawl again into the branchial
cavity. I shall send you a Porcellana, the integuments
of which are so soft that it must have moulted very
recently, and notwithstanding it has a very large Bopyrus
in its branchial cavity. Moreover, it seems to be im-
possible that the considerable deformation of the carapace
of the crab produced by the Bopyrus could disappear by
exuviation ; but I never found a deformed carapace with-
out the Bopyrus, although I have examined more than a
hundred Porcellane bearing the parasite.”—‘‘ I may here
observe, in Bopyrus Porcellane the right side is more
developed than the left when the parasite dwells in the
right branchial cavity, whereas the left side is the larger
when the Bopyrus dwells in the left branchial cavity.
The Bopyrus being fixed with its head directed backwards
naturally in the right branchial cavity, the right side of
the parasite can freely extend downwards, and therefore
becomes larger.”

PHRYXUS HYNDMANNI. 2438

ISOPODA. BOP YRIDA.
NORMALTIA.

PHRYXUS HYNDMANNI.

Female. Flattened above, ovate in outline, but slightly unsymmetrical.
Pereiopoda equally developed on both sides of the pereion. Pleon having
six segments, the segments being but little narrower than the hinder
segments of the pereion, each furnished at each side with a flattened,
rounded-oval scale or lobe, the two attached to the posterior segment being
rather more pointed; on the underside are two rows of elongate, conical,
fleshy lobes, obtuse at their tips, and slightly wrinkled transversely.

Length, about one-third of an inch.

WE are only acquainted with a single female individual
of this species, found attached to a Pagurus obtained at
Groomsport, Ireland, from ten fathoms depth, by Mr.
G. C, Hyndman, on the 24th of May, 1851, and by him
presented to the late Mr. W. Thompson, in whose col-
lection it is still preserved. From Phryzxus Paguri it is
at once distinguished by the rounded flat scales at the
sides of the segments of the tail, which, indeed, appear
rather to be but the Jateral extensions of the segments

R 2

R44 BOPYRIDA.

than lobes analogous to those of Ph. Paguri, fusticaudatus,
&c. The body is rather broadly ovate, nearly symmetri-
cal, the head being bent a little to the left; flat on its
dorsal surface, its ventral side being concealed by large
ovigerous scales, which do not extend over the sides of the
body so as to conceal the legs, which are not very robust.
The antenne are very minute, and in the middle of the
head, on the underside, is a small somewhat semicircular
raised lobe. The segments of the tail are continuous
with the hinder part of the body, the flattened lateral
scales of the former rendering the joints nearly as wide
as the latter, the pair of these scales attached to the ter-
minal segment are directed backwards and are somewhat
more pointed at their extremity. On the ventral surface
of the tail are two rows of fleshy somewhat elongate
cylindrico-conic appendages, obtuse at their extremities,
and which when stretched out do not extend beyond the
sides of the tail, and are consequently not visible from
above.

In addition to the specimens obtained from Hermit
Crabs described above and in the following pages, we
have received an exceedingly minute male, captured
on a Pagurus Bernhardus on the coast of Durham, which
we cannot satisfactorily assign to its legitimate partner.
It is preserved in Canada balsam, and is of an elongate
form, somewhat ovate in its general outline, with the
sides of the segments of the body and tail regularly
rounded, without any wide interval between them. The
outer antenne are sufficiently large to extend beyond
the sides of the head; they are three-jointed and seti-
gerous at the tip, and the inner antennz are extremely
minute and two-jointed ; the mouth appears to consist of a
conical tubercle in the middle of the lower surface of the

PHRYXUS HYNDMANNI. 245

head. The legs are very robust, but folded so as not to
extend beyond the sides of the body. The tail is com-
posed of six joints, gradually diminishing in width, the
last being very small, nearly oval, the tip pointed, and
with a minute seta on each side beyond the middle.

Dr. Fritz Miller, in a letter to us dated in 1864,
observes, that ‘‘ One of the most interesting animals of
this family is a Bopyrus living on Pagurus, in which the
dorsal surface of the parasite is directed towards the
Pagurus (I therefore named it B. resupinatus). The origin
of this curious manner of attachment is the following :—
The larva of Bopyrus fixes itself to the Sacculina purpurea,
living on the same Pagurus, and takes its nourishment
from the roots of the parasite. After the death of
the Sacculina, to whose ventral surface the Bopyrus was
fixed, the latter probably cannot change its position, and
remains with its dorsal surface facing the Pagurus.”

246 BOPYRIDA.

ISOPODA. BOPYRIDA.
NORMALIA

PHRYXUS LONGIBRANCHIATUS,

Male. Elongate, with the cephalon narrower than the pereion. The eyes
very minute. The segments of the pereion nearly equal, laterally separated
from each other by a considerable interval. Pleon composed of an elongate
ovate-conice piece, in which the segments are fused together.

Female. Ovate, flattened, slightly unsymmetrical, curved a little to the
left when viewed dorsally. Pleon with the six segments well defined,
narrower than the pereion, furnished with a pair of elongate fleshy lobes
on each side of each segment, and with four attached to the terminal
segment.

Length of the male, one line ; of the female, about one-fifth of an inch.

Tuts species is at once distinguishable from Phryaxus
Hippolyte and Ph. fusticaudatus by the greater number of
fleshy lobes at the sides and extremity of the tail of the
female, as well as by their different formation, which latter
character separates it from Ph. Paguri. The male has
the segments of the body of nearly equal width through-

PHRYXUS LONGIBRANCHIATUS. R47

out, the sides dilated laterally, with the anterior lateral
angles of each rounded off so that there is a considerable
interval between the segments. The tail, on the contrary,
has all the joints soldered into a solid piece. This sex is
furnished with very short, smooth legs, terminated by a
hand much larger than the preceding joints, with a rather
strong curved movable finger.

The female is oblong-ovate, flattened, slightly curved
towards the left, so as not to render it very unsym-
metrical. The eyes are very minute, the sides of the
segments impressed, with the legs inserted within the
impressions ; they are strong, with the intermediate joints
as large as the hand, and rugose on their underside.

The tail is about half the length of the body, nar-
rower than the terminal segments of the latter, each
joint furnished at each side with a pair of elongate fleshy
somewhat cylindrical lobes attenuated towards the tip,
the terminal segment being furnished, as appears to us,
with four of these lobes (one of the four being repre-
sented as attached to the left-hand pair of the fifth
segment in the right-hand figure of the woodcut illus-
trating this species).

This species bears some resemblance to Bopyrus folio-
sus of Kroyer, Voy. Scandinave, Crust., pl. 29, fig. 2, but
the rounder form of the pereion, the more elongated tail,
and the different form and apparent number of the ap-
pendages of the tail, and especially those of the terminal
segment, at once distinguish the last-named species from
the one before us. Kroyer’s specimens, indeed, appear to
form a connecting link between Phryxus and Athelges
cladophora of Hesse.

Our specimens of this species were forwarded to us
from Shetland, by Mr. J. Gwyn Jeflreys.

The Rev. A. M. Norman announces it from a specimen

248 BOPYRIDA.

of Pagurus Thompsoni, dredged off Tynemouth, Aug.,
1862.

From Polperro we have received specimens of both
sexes, captured by Mr. Loughrin, upon an old specimen
of Galathea squamifera, of a much larger size than those
represented above, the male being ;4ths and the female
11ths of an inch long. They precisely agree in general
form and in most of their details with the preceding. The
feet of the male are, however, more powerfully constructed,
with a semicircular emargination on the underside of the
hand, but the dorsal appendages of the basal segments
of the tail of the female are thicker and more rounded in
form, whilst the lateral ones as well as the four attached
to the terminal segment are more pointed at their extre-
mities and corrugated along their surface. These differ-
ences do not appear to us to be incompatible with the
enlarged size of the individuals, presuming that those
described and figured above are not full grown.

PHRYXUS GALATHES. Q49

ISOPODA. BOPYRIDA.
NORMALIA.

PHRYXUS GALATHEA.,

Male. Elongate; with the segments of the pereion rounded at the sides,
especially towards the hind margin of each. Segments of the pleon distinct,
transverse, rounded at the sides of each, narrower than the hinder segments
of the pereion, terminal joint truncated at its extremity.

Female. Ovate, flattened, and slightly unsymmetrical, ovigerous scales
of moderate size, finely ciliated on the margin, Pleon nearly triangular,
joints transverse, furnished with a number of elongated corrugated fleshy
cylindrical appendages, pointed at the tips.

Length of the male one-sixth, of the female one-fourth, of an inch.

Pleurocrypta Galathee. HussE, Ann. Sci. Nat., 3rd ser. vol. ii. pl. 4.

TuIs species nearly resembles Ph. longibranchiatus in
the general form of the female and in the elongated lobes
of the tail of the same sex. It differs, however, in its
habitat, being parasitic upon Galathea intermedia, and in
the distinct articulations of the tail of the male. Our
specimens of the two sexes are, however, preserved in

250 BOPYRIDA.

Canada balsam, and it is not impossible that they have
been somewhat distorted, and which also precludes our
examining them satisfactorily.

The male (represented on the left hand of our woodcut
of this species) has the segments of the body very dis-
tinct and rounded at their sides, the posterior lateral
angles of each being rather more rounded off than the
anterior angles; the six-segmented tail is narrower than the
hinder segments of the body ; its segments are, however,
equally distinct and rounded at the sides, truncated at
the hinder margin, the terminal segment being transverse,
with the sides rounded, and the extremity truncated.
The legs are strong and hooked; when folded in their
ordinary position, they nearly cover the underside of the
body. The first pair of antenne are three-jointed and
setigerous at the tip, whilst the second pair are five-
jointed, the terminal joint being very minute. The small
conical mouth appears to be protected on each side by
a minute two-jointed footjaw.

The female is broadly-ovate, with the ovigerous scales
rather narrow and fringed with a few minute seta. Both
pairs of antenne consist of three small joints; they are
minute, and somewhat conical in generalform. The legs
are longer, and comparatively not so strong as those of
the male. The mouth is represented as it appears in our
prepared specimen in the lower figure of our woodcut.
The tail is nearly triangular in form; it is furnished at
the sides and beneath with elongate-conic fleshy appen-
dages, the precise number and distribution of which we
are unfortunately unable to describe, but suppose that
there are two pairs to each of the six segments.

Our specimens were obtained from Shetland in 1864,
collected by the Rev. A. M. Norman.

IONE. 251

ISOPODA. BOPYRIDA,
NORMALIA.

Genus—LONE. (Latreilie.)

TuIs genus is at once distinguished from all the other
Bopyride, except Argeia of Dana, by the possession of
elongated branchial (?) appendages attached to the base
of the six anterior pairs of legs in the female, and by the
structure of the branchie affixed at the sides of the tail
in both sexes; all of these in the male, and the posterior
pair in the female, are elongated and filiform, whilst the
pairs attached to the five anterior segments of the tail
in the female are greatly elongated and multi-ramose,
resembling pieces of coral.

The male is ninute, resembling those of the Bopyri, with
the head distinct, the outer antennz prominently project-
ing beyond the front margin of the head, the inner pair
rudimentary, the seven segments of the body of nearly
equal size and width (except the first, which is shorter
than the rest); they are separated from each other by a
considerable space, having the lateral margins somewhat
angularly produced, the legs being affixed beneath the
lateral angles. The legs resemble those of the male
Bopyri, and are terminated by a small oval hand, with a
small curved finger. The tail is narrower than the hinder
segments of the body, and consists of six distinct seg-
ments, gradually narrowing in size, each segment being
furnished with a pair of elongated slender, cylindrical,
membranous appendages (pleopoda).

The female is much larger than the male, with the
body flattened, pear-shaped, and slightly unsymmetrical.
The head is transverse in front, its posterior portion being

252 BOPYRID.

narrowed so as to resemble a shield, and embedded in the
first segment of the body. Its anterior margin is dilated
over the base of the antennz, the extremities of which
extend beyond it. ‘The inner pair of antenne are
minute and rudimental; the outer pair are larger, and
composed of five joints, gradually attenuated, and ter-
minated by a small articulated flagellum. The mouth is
covered by a pair of lamellated foot-jaws, somewhat re-
sembling those of the genus Cymothoa, and the mandibles
are arranged as in the same group; but, as described by
M. Edwards, they are more slender towards the tip, and
are destitute of any articulated appendage. The other
parts of the mouth appear to be replaced by semi-mem-
branous lobes, of which the precise structure has not yet
been determined. The segments of the body are dis-
tinct, with the lateral margins sub-continuous, but desti-
tute of epimere, thus disagreeing with the Cymothoe.
The legs resemble those of the male; each of the six
anterior pairs are furnished beneath at the base with two
appendages of considerable size, one being broad, folia-
ceous, of a semi-corneous consistence, and folded beneath
the body so as to assist in forming a large ovigerous
pouch, covering the whole of the underside of the body ;
the other being an elongated slender membranous fila-
ment, which lies on the outside of the body, floating in
the water, and resembling the branchize attached to the
legs of the Amphipoda. The tail is small and ovate, with
the segments indistinct, except at the sides, where they
are marked by slight incisions; the appendages attached
to the five anterior segments are elongate, and branched
like a piece of coral, whilst the posterior pair are slender,
cylindrical, and simple. Several of the basal appendages
are, moreover, furnished at the base beneath with a small
scale, lying beneath the tail.

IONE. 253

The species are parasites on some of the most curious
genera of macrourous Decapoda, the British species in-
festing our only species of Callianassa.

The only specimen of this genus that we have had an
opportunity of examining was found on a Callianassa
taken by Mr. Lord in British Columbia. It was very
much larger than our British species, and is described as
fone cornutus by Mr. Spence Bate in the “ Proceedings
of the Zoological Society” for 1864.

The large size of the animal enabled us to examine
the detail of its structure with comparative ease. Laden
as it was with mature larve, the large ovigerous plates
covered the whole of the under surface except the pleon.
We saw nothing of the delicate narrow membranous
appendages attached to the legs that Professor M. Edwards
supposes to be branchiz, like those of the Amphipoda.

The organs of the mouth consist of several appendages
much differentiated, and co-operating together so as to
form one large oval mass, that was evidently endowed
with some degree of propulsive movement.

The mandibles consist of a pair of long narrow plates
that are serrated at the anterior edge, one being obliquely
convex, the other concave: the one that is concave being
convex nearer the base, while the reverse is the form of
the other, so that the blades being each a little curved,
the two meet at the point much in the form of a screw.
These cutting appendages are planted at the extremity
of the cesophagus, which, from its membranous character,
probably has a contractile power.

The two pairs of maxilla appear to be developed
round the mandibles as a strong support and frame-
work, the whole of which has the power of being
pushed out or withdrawn by the assistance of powerful
muscles that are attached to a strong osseous tendon

254 BOPYRIDA.

near the middle of each organ. On each side, near the
posterior extremity, exist two digital processes, the
secondary appendages of the maxilla. The maxilliped
consists of three primary joints, the first two being large
and squamous, the third small and rudimentary. Posterior
to the point where this joint articulates with the pre-
ceding, lies the secondary appendage which, like those
of the preceding pair, is digital in form, and points
backwards.

The appendages of the pleon consist of three kinds,
namely, a primary branch minutely articulated through-
out its length; the basal articulus, which probably
represents the coxa or first joint in the normal organ,
supports two appendages, one large and saccular, being
constricted at the base and pointed at the apex, the other
long, narrow, symmetrical, and pointed. These two ap-
pendages are constant on every pair of pleopoda, but
bear an inverse proportion to each other. In the anterior
pair the saccular branch is the more important, but
this gradually diminishes on each to the last pair,
where it is almost, if not quite, obsolete, whereas in the
first pair the digitiform process is the smaller of the
two; this gradually increases on each succeeding pair
of pleopoda, until in the last pair it forms the long
pair of caudal processes seen so conspicuously at the
extremity, and to which in this present species the male
was attached by means of the subprehensile claw of the
posterior pair of pereiopoda. To all the segments, except
the last, are attached one or more of the numerous
arborescent branches of which the mass of branchiz
is built up.

The male offers only specific variation from that of
our British species.

IONE THORACICA, 255

ISOPODA,
NORMALIA

IONE THORACICA,

Male.—Narrow, subparallel, first segment of the body shorter than the
following, the remainder with the sides subangulated.

Female.—Pyriform, flattened, basal appendages of the tail multi-ramose.

Length of female, about one-quarter of an inch.

Oniscus thoracicus. Monraat, Trans. Linn. Soe. ix. p. 108, pl. 5, f. 3.
Oniscus (Lone) thoracicus. Larrernin, Enc. Méth. pl. 336, fig. 46.
Tone thoracicus. LatreILuyE,in Regne An. Kd, i. iii. p. 54. LAMARoK,

Hist, Anim. sans Vertébres, v. p. 170. Dusma-
REST, Cons. Crust. p. 286, t. 46, f. 10. Guérin
Ménivittr, Icon. R. Anim. Crust. t. 62,
f. 1,2. Muitne Epwarps, Crust. iii. p. 280,
t. 33, f. 14, 15. Cuvier, Régne Anim. (Edit.
Crochard) Crust. t. 59, f. 1. Waurrr, B. M.
Cat. Brit. Crust. p. 81. Pop. Hist. Brit.
Crust. p. 254, pl. xiv. f. 8a (male), b (female).

Ir is to Colonel Montagu that we are indebted for the
first knowledge of this interesting parasite, which inhabits
the branchial cavity of Callianassa subterranea, concealing

256 BOPYRIDA.

itself between the branchial appendages and the carapace,
and forming a tumour on one side. From this situation
he extracted it alive, and kept it in sea-water for several
days. In all the specimens which he discovered the
female was attended by the minute male, which was con-
cealed amongst the arborescent appendages of the tail,
to which it was affixed firmly by its claws. He adds,
that the very disproportionate size of the sexes is wisely
adapted to an animal whose habitation is so confined.

As we are only acquainted with a single British species
(which is also found on the north-west shores of France),
it is unnecessary to redescribe the characters of the
species, which are included in those of the genus
given above. The colour of the animal is generally
orange, with the appendages whitish. Our figures are
copied from the beautiful ones published by M. Milne
Edwards in the Crochard Edition of Cuvier’s ‘‘ Régne
Animal,’”’ that author having been enabled to examine
recent specimens of both sexes. It was found by Colonel
Montagu in the Kingsbridge estuary, on the south coast
of Devonshire.

The Callianassa on which it lives exists in galleries of
its own excavation, about a foot beneath the surface of
the sea bottom.

Unfortunately, the specimen preserved in the British
Museum, and to which is attached a label in Montagu’s
hand-writing, is not an Jone, but a Bopyrus.

Brebisson (‘‘ Crust. Departm. Calvados”) states that
Tone thoracicus “ se trouve sous les pierres baignées par la
mer;” but we fear that he was misled by Latreille’s
incorrect reference of Oniscus ceruleatus (Praniza) to the
Oniscus thoracicus of ‘ Montagus,” in the “ Encyclopédie

?

Méthodique.” We cannot reconcile his description of

the animal with the true Ione.

CRYPTOTHIRIA. PADI

ISOPODA. BOP YRIDM,
NORMALIA,

Genus—CRYPTOTHIRIA.

Cryptothir. Dana (1852).

Liriope. Raruke (1843, not Lirtope of Lesson.—G. Meduse, 1839.)
Livriopsis. Scuuttze, Wiegm. Arch. 1859, p. 310.

Cryptoniscus. Frirz Miuumr MSS.

Hemioniscus. Bucunouz,

THE animals of this genus differ from those of most of
the genera of Bopyride inthe nature of their habitats(being
parasitic on crustaceans that are lower than themselves in
the natural classification) as well as in their structure ;
the supposed males, or at least the young, bearing a much
stronger resemblance to the young than to the full-grown
male Bopyri, whilst the females appear to be entirely
destitute of antenne, legs, branchial lobes, or other
appendages.

The supposed males and young are very minute, oval
or elongate in form, convex, with the head and segments
of the body and tail distinct, the former semicircular,
provided with two eyes and four antenne, of which the
anterior pair are very minute and slender, whilst the
posterior pair are greatly elongated, being about half
the entire length of the animal, composed of three or
four moderately long basal joints, followed by a multi-
articulate flagellum, of which the first articulus is the
largest. ‘The parts of the mouth have not been deter-
mined, but they appear to be covered by a large square
pair of plates (maxillipeds), of which the lower margin is
serrated, or possibly only fringed with hairs. Each of the

VOL. IT. s

258 BOPYRIDA.

seven segments of the body is furnished with a pair of legs,
affixed within the lateral margin on the underside; they
are more elongated than in the Bopyri, and more or less
hooked for prehension; they are nearly uniform in size,
the anterior pair being, however, the strongest, and the
posterior the longest and most slender in one or more of
the species.*

Each of the segments of the tail is furnished on the
underside with a pair of branchial appendages differing
in form in the different species, but very strongly fringed
with long sete.

The female is a large inert mass of animal matter,
destitute of appendages, and is affixed to the animal on
which it is parasitic. It is divided into two portions, the
one consisting, according to Lilljeborg, of four distinct
segments, which supports the organ or tube by which it
adheres to its prey, whilst the hind part of the body
consists of a simple sac for holding the eggs.

Writing to us on this genus, Dr. Fritz Miller says,
“* Changes in form not less important than those observed
in the Hyperina are to be seen also in the Bopyride. I
have already published the description of a new genus
of this family, Hntoniscus, whose retrograde metamor-
phosis proceeds much farther than that of Bopyrus (see
p- 265 post, note +). Ihave since found another species
of the same genus living in different Brachyura (Xantho,
&e.), and a second genus (Cryptoniscus, F. Miller,
MSS.), almost unrecognizable when adult; indeed the
female of it then resembles Planaria lactea rather than
an Isopod. It is, moreover, very interesting in its habits;
it does not take its sustenance directly from the little
‘Pagurus, on whom it is fixed, but from the roots of the

* In the species observed by Lilljeborg and Fritz Miiller (Zntoniscus
Galathee ) the young have only six pairs of legs.

CRYPTOTHIRIA. 259

Sacculina purpurea, which it kills, but whose roots, not-
withstanding, continue to grow and frequently attain
an extraordinary development.

“Tn the genuine Bopyride all the feet are of the same
form, while in Entoniscus and Cryptoniscus the sixth (or
last) pair show a very different structure.” The larva
of Cryptoniscus has the sixth pair of pereiopoda long,
slender, and styliform. That of Entoniscus has the
same limbs long and slender, with large and powerful
prehensile claws.

M. Hesse, in his Fourth Memoir on Rare or New
Crustacea of the coasts of France, ‘‘ Ann. des Sci. Nat.
1864, ser. v. vol. ii. p. 281,” described and figured the
female of Peltogaster tau, which he found on Paguri,
together with its monoculoid-cirriped-like embryo. More
recently (in his Tenth Memoir, Jdzd. vol. vi. p. 321, 1866)
he gives an elaborate account of P. paguri, in which he
describes an animal, of which he had only taken a single
specimen on a Pagurus, and which he considers, without
sufficient proof, as the male, together with the female,
and the young animal in its earliest stage of develop-
ment. The earliest form of the larva he describes as
resembling that of the Entomostracous crustacea, and
states that, as in all of the suctorial crustaceans, the
larva has three pairs of appendages. He also describes
it as having lateral processes on each side of the anterior
margin of the head, and that these processes are im-
mature antenna, thus proving its relationship with the
Cirripedes, and leading us to infer that the parent animal
which he figures as the female is bisexual, and that his
supposed male has no connection with the female, but
must be considered as that of a Bopyroid crustacean,
possibly of a Cryptothiria in an advanced stage of

s 2

260 BOPYRIDA.

development. Lilljeborg, Rathke, and Buchholz, on
the contrary, describe and figure the larva of the present
genus as we find it to exist among the Bopyroid crustacea
generally, and which is a modification of the typical

Isopod.

INTERMEDIATE PRANIZA-LIKE FORM OF THE FEMALE OF C. BALANI, FROM
BUCHHOLZ.——(See p. 271.)

CRYPTOTHIRIA PYGMAA. 261

ISOPODA. BOPYRID.
NORMALIA,

CRYPTOTHIRIA PYGM@A.*

Specific character. — Supposed Male. — Elongate-ovate, posteriorly at-
tenuated, convex above, concave beneath. Cephalon rather longer than the
following segment. Anterior pair of pereiopoda strongest; posterior pair of
pereiopoda long and slender. Sixth or terminal segment of the tail forming
a minute plate, covering the base of the hind pleopoda.

Female with the body divided into two portions, the anterior composed of
the head and three following segments, connected by means of a constriction

* The woodcut at the head of this article represents the male of C.
pygmea, and the extremity of its body highly magnified, from specimens
furnished by the Rev. A. M. Norman. The female C. pyymca (copied
from Lilljeborg) is the upper left-hand figure; Rathke’s figure of the young
C. pygmea (which, if the form of the antenne be correct, is undoubtedly a
male of mature form) is copied in the upper right-hand figure ; whilst the
lower right-hand figure is copied from Lilljeborg’s figure representing the side
view of the young of LZ. pygmea.

262 BOPYRID.

or neck with the hind part or matrix, which is exarticulate or sacciform,
kidney-shaped, destitute of appendages.
Length of male, one-tenth of inch ; female, (?)

Liriope pygmea. H. Raruxe, Reise Bemerk. aus Skand. in Neust.
Schr. Naturf. Ges. Danzig, tom. 2, p. 105—110
(1841). Nova Acta Acad. Cs. Leop. Nat.
Curios. tom. 20, p. 244, pl. 1, figs. 8—12.
LitigEBoRG, Liriope et Peltogaster, in Nova Acta
Reg. Soe. Upsal. ser. 3, vol. iii. p. 6, pl. 1, figs.
1—23 (1859). Suppl. to ditto in ditto, pl. 6,
figs. 1, 2 (1860).

Oniscus squilliformis. Patuas, Spec. Zool. fase. 9, p. 50% CAVOLINI,
Memoria sulla Generaz. dei Pisci e dei Granchi,
transl. Erzeugung der Fische u.d. Krebse, pp. 164,
165, pl. 2, figs. 18 m, n, r, r.

Tue history of this species has been remarkable, nor
can it yet be regarded as free from diificulties. Cavolini,
as quoted above, first described and figured two different
crustaceous animals (one of which he doubtingly referred
to the Oniscus squilliformis of Pallas) which he had
found parasitic within a sac attached to the tail of a crab
belonging to the genus Portunus or Carcinus. In 1889,
Rathke found in the Norwegian Sea, upon the bodies of
Carcinus menas and Pagurus Bernhardus, two species of
vermiform parasites, which he regarded as belonging to
the Entozoaria (but which have since been proved, by
their transformations, to belong to the Cirrhipeda), and
which have subsequently been described under the names
of Pachybdella Carcini * and Peltogaster Paguri.

Within the body of the latter of these two parasites
Rathke found eight minute crustaceans, which he con-
sidered had been devoured by the Peltogaster, and which
he described under the name of Liriope pygmea, referring
them to the order Amphipoda, unaware that the generic

* Professor Bell, in his volume on the Stalk-eyed Crustacea, p. 108, de-

scribes the female of this parasite (Pachybdella carcini) as infesting Por-
tunus marmoreus even to a greater extent than Carcinus menas.

CRYPTOTHIRIA PYGM#A. 263

name had been employed four years previously for a
genus of Meduse, by Lesson.

Steenstrup, in the “ Oversigt’ of the Royal Danish
Society for 1854 (pp. 145—148), considered that this
minute Liriope, instead of having been devoured by the
Peltogaster, was either a parasite upon it, or that it was
its young state. Professor Schmidt having, however,
shown that the young of the Peltogaster resembled that
of the Cirripedes, Steenstrup (subsequently, op. cit.
p- 214) abandoned his former opinion, leaving the ques-
tion unsettled.

In the *‘ United States Exploring Expedition,” Crust.
p- 801, pl. 53 (1852), Dana described a new genus (which
he unnaturally placed in the family Tanaide), under the
name of Cryptothir, remarking, as Steenstrup had done,
that Rathke’s Liriope was not an Amphipod, but in reality
an Isopod crustacean. Steenstrup had, however, referred
Liriope to the family Balanide. Three or four specimens
of the Cryptothir minutum were taken separately in as
many individuals of the corallidomous barnacle, Creusia.

In 1858 Lilljeborg found in the Norwegian Sea a
Pagurus pubescens with a Peltogaster attached to its tail;
but the parasite appeared to be double, one portion being
filled with eggs, and which he consequently considered to
be the single ovigerous sac of the parasite hanging sus-
pended from the body, as is the case with the double egg-
sac of the Cyclops, &c. But the fact that the Peltogaster
was a suctorial animal, and not a mandibilated one (like
the Cyclops), and that the egg-sac had motions inde-
pendent of the Peltogaster, even after the latter had died,
and the body of the Pagurus had putrefied, greatly per-
plexed Lilljeborg. He then examined the sac and its con-
tents more carefully, and discovered that the former was a
distinct animal, parasitic upon the parasite, and that the

264 BOPYRIDA.

young were totally unlike the Cirriped-formed larvx of
the Peltogaster, and that they exactly resembled Rathke’s
Liriope; thus proving that the body of the supposed
Peltogaster of Rathke, in which the Liriopes were found,
was, in fact, the superposed body of the second parasite,
or, in other words, that the female of Liriope was now
discovered, that Rathke’s animals were the young of that
female, that Dana’s Cryptothir, found upon a Balanus,
was either the young or male of a closely-allied animal,
and that Cavolini’s parasite, found upon Portunus, was to
be referred to the same group. As the minute and active
Liriopes were found, both by Rathke and Lilljeborg,
within the egg-sac of the parasitic female, the question
arises (and is still undetermined) whether these little
creatures are exclusively young males, or are the larve-
form of both sexes? and whether the adult male does or
does not retain its larva shape almost unaltered during
the whole of its life? Analogy with the stages of de-
velopment of the Bopyride, and especially with those of
the following species, would lead us to adopt the opinion
that in their earliest stages both sexes of this genus
are alike in form, and that whilst the female gradually
loses the articulated character, together with all the
external appendages of the body, the male retains much
of its larva condition. Such is the opinion of Lilljeborg,
who has argued the question at considerable length, and
such appears probable on taking into consideration the
comparative characters of the young and adult males of
Bopyrus squillarum (as represented in our figures in p. 218),
of Gyge galathee (p. 225), and of Jone thoracica (p. 254),
and those exhibited in our several figures of the young
or males of this species, given by Rathke and Lilljeborg
copied as above, and our own as given in the cut at the
head of this article. According to Lilljeborg, however,

CRYPTOTHIRIA PYGM®A. 265

the youngest state of the animal has only six pairs of
legs, the sixth being half as long again as the others,
and terminated by a very slender elongated finger, whilst
the five preceding pairs are of equal size, and sub-
cheliferous.* Rathke, on the contrary, although he
only figures four of the legs on one side of the body
of his Lirtope (the fourth being minute and slender),
expressly states, in the description of his figures, that his
detached figure of this hindmost leg represents the seventh,
or posterior one. As it is impossible, however, to over-
look the strong relationship which evidently exists between
the Lzriope and Entoniscus Porcellane,} elaborately de-

* Lilljeborg’s statement seems fully confirmed by Fritz Miiller’s description
of the larva of Hntoniscus Porcellane.

+ The female of this remarkable parasite resides within the body of a
species of Porcellana, lying in a thin-walled sac between the liver, intestine,
and heart of its host, the head being ‘‘ destitute of eyes and antenne ;
the thorax has become an irregular inarticulate sac, beset with enormous
brood-laminz ; the long vermiform and extremely mobile abdomen has sword-
shaped legs; and swelling out above it in a globular form, as if in a hernial
sac, the heart lies at the base of its first segment!’ The young of this sin-
gular parasite closely resembles that of Bopyrus and Liriope, being oblong-
ovate and flattened in form, with one pair of antennze very short and thick,
whilst the other pair is half the length of the body, and bent backwards.
‘«The five anterior segments of the thorax bear similar feet, terminated by a
thickened ovate palm, and a slightly curved powerful claw.” The sixth pair
of legs are only three-jointed, the last joint being elliptical. There is no
seventh pair of legs. ‘‘ The abdomen bears, first of all, four pairs of natatory
feet, with a crescentiform basal joint, and a lancet-shaped terminal joint,
furnished with strong bristles.” The fifth abdominal pair of legs is a narrow
and short appendage, without bristles, cleft into two unequal divisions ; and
the terminal pair of appendages consist of a thick basal joint and two slender
biarticulate terminal branches.

The male somewhat resembles that of the Bopyride. The body is elongate-
obovate and regularly articulated, the head is trapezoid, with rounded angles
extending considerably beyond the sides of the following segment. The only
pair of antenne are short, inarticulate, flat, and quadrangular. The mouth
forms a ‘triangular rostrum.” ‘‘The stz anterior thoracic segments bear
feet reduced to nearly sessile inarticulate roundish lumps. The seventh seg-
ment has no feet, but bears on each side, at the posterior margin, a wart-like
process, and on this the genital orifice.” The abdomen is considerably elongated
and narrow, composed of six segments entirely destitute of appendages.

266 BOPYRIDA.

scribed by Fritz Miiller (Archiv. f. Naturg. xxviii.
p- 10, and Ann. Nat. Hist. 3 ser. x. p. 87, pl. 2), we are
led to the conclusion that the animal we figure from
our own drawing is a young male of this genus, and that
in its full-grown state it may be somewhat modified in
the form of its locomotive organs.

The female of C. pygmea is now, however, satisfac-
torily known by the researches and figures of Lilljeborg.
It consists of two separate portions in its adult ovigerous
state, the anterior being convex and smooth on the upper
side, and concave beneath, composed of four segments,
of which the two central ones are the largest; the first,
or head properly so called, constituting an organ by which
the animal affixes itself upon the Peltogaster. The hind
part of the body is exarticulated, sac-like, kidney-shaped,
and convex above, with a slit on its underside through
which the young are expelled. There is not the slightest
vestige of antenne, eyes, mouth-organs, prehensile or
branchial legs.

Our specimen of the supposed male was taken with
the dredge off Guernsey by the Rev. A. M. Norman,
not attached to any animal, but he found it in a bottle in
which crustacea, for the most part Amphiphods, had been
put.

CRYPTOTHIRIA BALANI. 267

TISOPODA. BOP YRIDA.
NORMALIA,

CRYPTOTHIRIA BALANT.

Specific character.—Immature (?) Male.—Elongate-ovate, cephalon fur-
nished beneath with two flat lobes, serrated on their posterior margins, mouth
forming a conical process ; upper antenne very short, lower antenn nearly
half the length of the animal, reflexed ; pereion with seven pairs of pereio-
poda, first and second pairs with strong palms and hooked fingers, five pos-
terior pairs slender and simple. Pleon with five pairs of branchial appen-
dages, each composed of two lobes.

Adult Female.—Forming a large inert seven-lobed mass, destitute of ex-
serted antennz, jaws, legs, or branchial appendages.

Length of the supposed male, about one line ; female, about one-quarter of
an inch.

Liviope balani. Spence Barts, Brit. Assoc. Report, 1860, p. 225.

Hemioniscus balant. Bucwuowz, in Siebold and Kolliker, Zeitschr. f.
Wissensch. Zool. xvi. 3 h. p. 303 (September,
1866).

Balanus balanotdes, male. Goovstr, H. 8., on the Sexes of the Cirri-
peds, &c., Edin. New Phil. Journal, p. 88, v. 35
(1843). Ann. d. Sci. Nat. 3 ser. Zool. t. 1.
PIAS c:

Tue first notice we possess of this animal is that given

268 BOPYRIDA.

by Mr. Henry Goodsir in the ** Edinburgh New Philoso-
phical Journal for 1843,” where he erroneously described
the female, or the animal represented in our right-hand
figure, as the male of the cirriped (Balanus balanoides),
and the animal, copied in our left-hand figure, as being
parasitic upon that supposed male.

About the time of the publication of a memoir in the
** Annals of Natural History,” ‘‘ On the Development of
the Cirripeds,” in 1851, our attention was drawn to a fleshy
mass of material that we found attached to the base of
the animal of the Ba/anus balanoides, lying within the
shell. This we first took to be the ovisac of the Balanus,
because we found it always full of ova, which we then
thought were the ova of the Balanus in one particular
stage. In this we thought we were confirmed by the
fact that we never found the ova of Balanus in the condi-
tion most familiar to us in any of those specimens where

these ova were found. A drawing of the mass, which

is

DEVELOPMENT OF LARVA OF CRYPTOTHIRIA BALANI.

we submitted to Mr. Darwin, induced him to suggest it
as being the parasite that Mr. Goodsir described as the
male of the cirriped; and an examination of the article

“On the Sexes of the Cirripeds,” clearly showed us that

CRYPTOTHIRIA BALANI. 269

Mr. Goodsir’s figures were more or less perfect repre-
sentations of the mass that we had observed.

The young, which we have frequently taken in an
incomplete stage, are developed as in true Isopoda; and
the earliest larval condition, as figured by Goodsir and
Rathke, shows that the animal is, both in its develop-
ment and parasitic habit, closely allied to the Bopyroid
crustacea.

The animal represented in the middle of our wood-
cut, which we consider to be the male, corresponds, so
far as the head and anterior segments of the body are
concerned, with that which Mr. Goodsir has figured as
being the anterior segments of his supposed male, and,
if Mr. Goodsir’s dissections be true, appears to offer a
very considerable evidence of the near relation of the
two animals. But we were inclined to think that
Mr. Goodsir’s figures, 1—3 in pl. 3, which he gives as
the concealed cephalic portion of what he calls the male
of the Balanus, and the entire dorsal view of the same
animal given in pl. 4, fig. 10, were taken, the former from
the real male, and the latter from the female, Lzriope.*

Though frequently having taken the females in con-
nection with the Balanus, and these also charged with
ova in various stages, we have never taken the male asso-
ciated with the female, as is almost invariably the case
with the other genera of the Bopyride. In this species

* Tn the elaborate memoir of Dr. Buchholz above referred to, published
last September, the learned author has arrived at an opposite conclusion rela-
tive to the true condition of our supposed male, which he has carefully figured
and described as the larva-form of the species, and which, in certain indi-
viduals at least, becomes developed into the female, the fully developed con-
dition of the male being still unknown. This observation completely supports
the correctness of Goodsix’s statement, that his figures 1-3 represent the
anterior articulated part of the animal of which a dorsal view is given in his
figure 10, in which, however, the articulated portion is concealed by the
swollen front of the second division of the body.

270 BOPYRIDA.

we have always found that which we consider as the
male animal to be free, and roaming distantly from its
supposed mate. The cirriped which it infests (Balanus
balanoides) is a gregarious species, and lives upon the
rocky shore between the tidal marks, and we have fre-
quently seen, on breaking off a mass of the Balani, the
little red crustacea run away, and the paucity of the
males that we observed in comparison with that of the
females, has induced us to consider that the male wanders
about from one cirriped to another. The animal is of
a red-brown colour, and is an active little creature.

The female, in its adult state, is a large inert inarticulate
mass, destitute of antenne, mandibles, or foot-jaws, legs
or branchial appendages, with the bedy dilated on each
side into three large rounded or conical lobes, the tail
itself forming a terminal lobe similar to the others. In
Dr. Buchholz’s specimen the body (probably from having
been immersed in spirits) was of a broader and rounder
form than in our figure, with the lobes more conical and
more regularly radiating, giving the animal more of a
star-like appearance. It is furnished with a short mouth
or sucker, by which it affixes itself to its prey.

The young animal, as described by Buchholz, or the
male as suggested above, is elongate (more ovate in
Buchholz’s figure than in our own), with the head as
wide as the following segment, which, as well as the
remaining segments of the body (and also of the tail,
according to Buchholz), have the lateral margin deflexed,
with its posterior margin serrated. The mouth consists
of a conical process, protected above by two flattened
plates, of which the posterior margin is serrated. The
minute pair of upper antenne are affixed at the sides of
these appendages, and consist of a strong basal joint,
thickly fringed with long sete, and a terminal articulated

CRYPTOTHIRIA BALANI. QF

flagellum. The lower antenne are strong and elongated,
consisting of four large basal joints, gradually diminishing
in length and thickness, and terminated by an articulated
flagellum. The seven segments of the body are furnished
with the same number of legs, of which the first and
second pairs are shorter and more robust than the rest,
and terminated by an oval palm anda movable finger.*
The remaining five pairs of legs are long and slender, the
seventh or last pair especially being longer than the rest.
The tail is obconical, the five anterior segments being
furnished on the underside with as many pairs of
branchial appendages, each consisting of an oblong basal
piece, bearing two terminal branches, of which
the inner is long and conical, and the outer
shorter and pointed. Buchholz, on the con
trary, represents them as consisting of a dilated
basal subtriangular joint, terminated by two
oval or suboval plates, strongly fringed at the

posterior margin with long sete.

The transformations which this minute active pedi-
gerous animal undergoes in assuming the adult female
form have been carefully observed and figured by Dr.
Buchholz. In the earliest of these changes we observe
a striking analogy with the form of the female Anceus, °
the three posterior segments of the body coalescing,
losing their articulated character, and swelling out into a
large mass, in which the segments are only indicated by
lateral impressions; those of the tail, however, remain-
ing distinct.+ In the following stage the tail is entirely
absorbed, forming a terminal exarticulate conical mass,
continuous with the lobes of the body, but with the

* In our specimen we could not determine the precise form of the first
pair of legs, and which are not quite correctly given in our figure.
+ See Vignette in page 260.

22 BOPYRIDE.

head and four anterior segments and legs of the body
still distinct. Im the next stage the great terminal mass,
forming seven rounded lobes, is much increased in size,
the fourth segment of the body has become absorbed,*
and a large membranous dilatation also appears on the
underside of the general mass. In the final stage all
distinct traces of the head and three anterior segments
appear to be lost, and the animal reduced to the inert
mass represented in the right-hand figure of the wood-
cut at the head of this article. According to Buchholz,
however, the full-grown female still retains the antennz
and fore pair of legs, although immersed in the fore
portion of the sac-like envelope of the rest of the
body (see his fig. 4 in pl. xvii. ‘f Vorderkorper eines
erwachsenen individuums von dem Sacke abgetrennt”).
It is from this circumstance, as well as from a considera-
tion of the character and number of the legs and
branchial appendages of the immature state that Dy.
Buchholz was led to separate this animal from Liriope as
described by Lilljeborg, under the name of Hemioniscus.
Until, however, the males of both species are positively
determined, we consider it more advisable to retain them
both in one genus.

* The animal in this state exhibits a striking analogy to the adult gravid
female of the Chigoe (Pulex penetrans).

CYMOTHOIDA. Qs

THE second subtribe of the Parasitical Normal group
of the Isopoda contains all those species in which the
sexes are not materially unlike each other, the males
being generally nearly as large as, or larger than, the
females, with the dermal tissue hard and crustaceous,
the pereiopoda well developed, the oral organs formed
for mastication, the mandibles being horny, having the
terminal half narrowed and curved inwardly, with the
apex formed for gnawing, the base also furnished with a
triarticulate appendage. The pleon is terminated by a
large flat crustaceous plate representing the sixth seg-
ment, bearing near its base at each side a pair of elongate
flattened lobes (uropoda) arising from a dilated base.

These animals compose the family of Cymothoadiens
of Milne Edwards,* which he has divided into three
tribes corresponding with our families—namely, 1. Cymo-
THOADIENS RAVISSEURS or SEROLIDE; 2. C. ERRANS
or A’cip=; and 3. C. PARASITES or CYMOTHOIDZ.

The first of these tribes consists of the singular genus
Serolis, the species of which are thought by many to
offer a very strong resemblance to the Trilobites. They
are all natives of the Ocean surrounding South America,
and are distinguished by their flat circular form with
moderately long antennz, and with the first or the first
and second pairs of legs strong and cheliferous, whilst
the remainder are slender and fitted for walking.

The second tribe corresponds with our family Accipa,

* The Cymothoade of Dr. Leach’s article in the ‘‘ Dictionnaire des Sciences
naturelles” was still more extensive, as he introduced into it not only the
groups admitted by M. Milne Edwards, but also our Sphwromide and the
genus Limnoria.

VOL. II. T

274 ISOPODA.

whilst the third tribe, C. parasites, forms our restricted
family CyMoTHoID#&, the species of which are parasitic
on fishes, all their legs being alike in form and strongly
hooked for prehension, they are all, as well as the
antenna, short, and the latter are always inserted on
the underside of the head, beneath a prolongation of the
forehead, and the body is of a less firm consistence than
in the gide, thus approaching the Bopyride. The
species are numerous, but chiefly inhabitants of Tropical
Seas ; some few are, however, known to inhabit more
temperate climes, but no specimen has hitherto been
satisfactorily determined as having been found in our
own seas, although Cymothoa Ciistrum * is introduced by

* Cymothoa, Fabricius, is distinguished from the other genera of this tribe
or family by having all the segments of the pleon distinct and movable, the
pleon itself considerably narrower than the terminal portion of the pereion,
the last segment wider than long, and the legs tolerably strong and subche-
liferous.

Cymothoa Cistrum' is distinguished from the other species of the genus
by having the anterior margin of the cephalon advanced and bent down
between the inner antenne, which are inserted widely apart, the first segment
of the body very large and advanced beyond the head on each side, and by
the lower edge of the bases of the fourth pair of legs armed with a strong
tooth.

This species is found in the Atlantic Ocean and in the Seas of both Indies.
It attacks fish, and makes occasionally large wounds suflicient to cause the
death of the individuals attacked.

1 Oniscus Gstrum, Lixn. Syst. Nat. pp. 1059, no. 2, Faun. Suec. no.
2053. Mus. Adolph. Frid. 89. Fasricrus,
Syst. Ent. p. 294. Sp. Ins. i. p. 375, no. 4.
Patuas, Spic. Zool., fasc. 9, p. 74, tab. 4,
foes) SAC.

Cymothoa strum. Luacu, Edinburgh Ene. vii. pp. 405 and 433.
Ene. Brit. Suppl. 1, p. 428. Trans. Linn.
Soc. xi. p. 872. Dict. Sc. Nat. t. 12, p. 358.
SAMOUELLE, Ent. Compend. p. 109. Dzs-
MAREST, Cons. Crust. 309, pl. 47, figs. 6, 7.
Minne Erwarps, Hist. N. Crust. 8, 269.
Régne An. (Crochard Hdit.), Crust. pl.65,f.1.

Asellus strum. OxivieR, Ene. Méth. 4, 253.

EGIDA. 275

Samouelle into his work on British Insects, without, how-
ever, any locality being subjoined, and, as it is omitted by
Mr. White in his Catalogues of the British Crustacea,
it seems evident that no tradition exists in the British
Museum (of which Mr. Samouelle was also an officer)
to warrant its introduction. As it is possible, however,
that it or some other of these fish-parasites may occur,
we have introduced the above family characters.

In the second tribe of Milne Edwards, forming our

Fam.—AGIDA,

The species are amongst the largest known Isopods,
and are distinguished by having their antenne fixed
in front of the head, the basal joint of the anterior pair
being very broad and flat, and uniting together to form
a margin in front of the head, not being concealed
beneath the advanced cephalon; the outer-foot jaws
have the basal joints moderately dilated, with three
or four terminal joints, which are rarely palpiform; the
pereiopoda are of moderate length, the anterior pair
being generally the strongest and fitted for prehension,
being terminated by a robust curved finger, acute at the
tip; whilst the hind legs are gradually elongated and
fitted for walking. The five segments of the pleon are
very short, each on its underside supporting a pair of
double foliaceous plates for respiration, whilst the last
segment of the pleon is large and flat, and bears on each
side near the base a pair of flat appendages, scales arising
from a basal joint, of which the inner angle is sometimes
produced into a long style.

276 EGIDA.

TSOPODA. AGID 4,
NORMALIA.

Genus—/AGA. (Leach).

Generic character. The three anterior pairs of legs in this
genus are strong and terminated by a powerful hook-like finger,
whilst the four posterior pairs are longer and more slender,
with a but slightly curved terminal finger, so as to fit them
for progression; the short inner antenne have the basal joints
very broad and flattened, occupying the front margin of the
head.

THE species of this genus are of large size. They
are oval, moderately convex, with most of the segments
marked transversely with a slight ridge. ‘The cox or
first joint of the legs (epimeral pieces of Milne Edwards)
are formed so as to appear as part of the dorsal surface.
The eyes are of large size and oval, extending consider-
ably backwards at the sides.

The outer antenne are affixed beneath the fore margin
of the head, and are separated from each other by an ele-
vated scutcheon-like piece or labrum ; they are composed
of five or six strong basal joints gradually increasing in
length, but diminishing in thickness, and are terminated
by a flagellum composed of about a dozen articulations.

The mandibles are strong, with the apical portion angu-
lated and bifid ; they are furnished with a prominent three-
jointed palpiform appendage arising near the external
base. The outer-foot jaws are rather valve-shaped, with
the basal joint strong and elongated, bearing a triangular

EGA, pay 9)

lobe on its external base; the second joint is produced
internally, and the three terminal joints are short, the
last being armed with several minute teeth; the outer
pair of maxillz are curved and slender, terminated by
two denticulated pieces, and the inner pair of maxille
are still more slender, with several minute reflexed teeth
at the tip.* The pleon is nearly as wide at the base as
the terminal segment of the pereion; the four anterior
segments are of equal size and short, with the lateral
margins strongly produced posteriorly into an acute
angle; the fifth segment is shorter than either of the
preceding, whilst the terminal segment is large, flat,
conical, or semiovate or semicircular, often with one or
two central ridges ; each of the five basal segments bears
on its underside two pairs of delicate membranous ciliated
branchial plates, all of nearly equal size, and each pair
arising from a transverse basal piece. ‘They do not cover
the whole of the underside of the tail. The terminal
segment also carries on each side a pair of flattened
appendages that do not reach beyond the posterior
extremity of the pleon.

* Our description of the parts of the mouth is made from ga bicarinata.
In Milne Edwards's figures of details taken from Aga emarginata, the diffe-
rent organs appear to be less denticulated at the tips.

278 HEIDA,

ISOPODA. AAGIDA,
NORMALIA.

MGA BICARINATA.

Specific character. Animal depressed, terminal segment of the pleon wide
at its extremity, bearing on its upper side two diverging carinated lines,
which terminate at the posterior angles, the intervening space nearly straight
or slightly emarginate. Uropoda with the inner division larger than the outer,
truncated at the inner extremity.

Length, 13 inch.

ga bicarinata. Luacu, Dictionn. Sci. Nat. xii. p. 549, DEsMAREST,
Cons. Crust. p. 305. Minne Epwarps, Crust. iii.
p. 241. Cuvier, Régne An. (Edit. Crochard), Crust.
t. 67, f. 2. Raruxn, in Nov. Acta Ces. Leop. Nat.
Curios. vol. xx. pJ. 6, f. 1—12. Wurrse, B. M.
Cat. Brit. Crust. p. 79. Pop. Hist. Brit. Crust.
p. 251, pl. xiv. f. 5. Gossz, Man. Mar. Zool. 1,
fig. 232.

Tuts is one of the largest species of known Isopods,
some individuals measuring about one inch and a half in
length. It is at once distinguished by the two elevated
divergent lines on the terminal segment of the tail and by

EGA BICARINATA. 279

the larger size of the inner division of the appendages
at the sides of that part of the body, which is, moreover,
somewhat truncated at its inner extremity, whilst its
outer margin has a slight emargination near its extremity.
The eyes are wide apart and occupy the posterior angles
of the head.

The upper antenne are scarcely longer than half the
width of the head; the basal joint is large, flat, and
square, the second joint produced along its anterior mar-
gin so as partially to conceal the base of the third joint
(when seen from beneath), which is slender and succeeded
by a very short flagellum, consisting of five or six arti-
culi; the lower antenne are aboutas long as the width of
the head, and have three short thick basal joints; the
fourth is longer than the third, and the fifth nearly as
long as the fourth, but more slender, and is followed by
a flagellum, consisting of twelve articuli; these organs
are separated at the base by a scutellum-shaped labrum,
arising from a transverse keel or epistome. At the sides
of each segment of the pereion the coxe of the legs are
developed as parts of the dorsal surface (epimera), and
have their outer portion raised and curved so as to form
elevated spines overlapping each other; the segments
themselves are marked across the middle, or nearer the
base, with a raised line; the four anterior segments of the
pereion are of equal size. ‘The surface of the pereion
is seen, under a strong magnifying power, to be entirely
covered with very minute circular punctures, amongst
which larger and more irregularly shaped ones are dis-
posed without order.

Our drawing is made from Dr. Leach’s original type
specimen in the British Museum, to which his own ma-
nuscript name is still attached. In this specimen the
extremity of the tail is formed precisely as represented

280 EGIDA.

in our figure. Dr. Leach, however, in his description,
says, ‘‘extremité presque tronquée, échancrée.”

The species inhabits the Mediterranean, and is also
found not unfrequently on our coasts.

Specimens from St. Leonards are in the Hopeian
collection at Oxford. We have also obtained it by
trawling in Plymouth Harbour at the beginning of
February, and have received it from the Rev. A. M.
Norman, who has taken it on the coast of Durham.

The Oxford Museum also possesses a small specimen
labelled as having been taken at Plymouth, which was
considered by Mr. Hope as a distinct species (the MS.
name of ‘‘Spilota, Hope,” in the handwriting of the
donor himself, being attached to it), it being dotted all
over with small brown spots, arranged at equal distances
apart, so that there are about a dozen occurring next the

posterior margin of each segment.

EGA TRIDENS. 281

ISOPODA., AiGIDA.
NORMALIA.,

AGA TRIDENS.

Specific character. Differs from ga bicarinata in having the last seg-
ment of the tail furnished with three carinw, each of which is produced into
a small point beyond the posterior margin of the segment, the space between
the two lateral teeth being emarginate ; eyes large, having only a small space
between them in the centre of the anterior margin ; inner plate of the caudal
appendages larger than the outer and truncated at its extremity.

Length, an inch and a half.

tga tridens. Leacu, Trans. Linn. Soc. xi. p. 370. Dic. Sc. Nat. xii.
p. 349. Desmarzst, Crust. p. 305. Mritne Epwarps,
Crust. iii. p. 242. Wuuitz, B. M. Cat. Brit. Crust.
p. 80. Pop. Hist. Brit. Crust. p. 251.

Var. ? with central spine of tail obsolete. ga monophthalma var. minor.
Jounston, in Loudon’s Mag. Nat. Hist. vii. p. 283,
fig. C. (?)

THIs species is closely allied to Aga bicarinata, but is
distinguished by the three carinz on the terminal segment
of the tail, the two lateral ones being the strongest, and
each terminating in a small tooth on the posterior edge of

282 AGIDA.

the tail, which is emarginate. The body is elongate-ovate,
and convex, the eyes large and nearly meeting on the
crown; the upper pair of antenne are not longer than the
head, with a flagellum composed of about twelve articula-
tions, the two basal joints very broad (the second obliquely
emarginate), with the flagellum affixed on its hinder angle.
The coxe of the legs attached to the anterior segments
of the pereion are subquadrate and marked with straight
elevated ridges; these are represented in our upper right-
hand figure as seen on the underside of the body, show-
ing the base of the three fore legs on the left side.

The branchial plates on the underside of the body (as
represented in our lower left-hand figure) scarcely ex-
tend beyond the middle of the terminal segment; they
are all of nearly equal size, the upper or outer pair not
covering the whole or even the following pair. The
lateral appendages also, when folded up, scarcely extend
beyond the lateral margins of the terminal segment, the
truncated extremity of each inner division uniting and
leaving a triangular space uncovered at the extremity of
the tail; the outer division of these lateral appendages is
considerably smaller than the inner, and elongate-ovate
in form, pointed at the tip, with the outer edge armed
with spines arranged in transverse rows.

The typical specimen of this species described by
Leach was contained in Sowerby’s collection from Scot-
land, and Mr. Gregor has sent it to us from the Moray
Frith, and there are others now in the British Museum
from Belfast, presented by Colonel Portlock.

The late Mr. W. Thompson, of Belfast, also obtained
it from Belfast Market, where it was found among Car-
rickfergus oysters, at the end of March, 1839, and also
from a cod-fish brought to the same market in February,
1841.

GA PSORA, 283

ISOPODA.
NORMALIA.

fiGA PSORA.

Specific character. Oval and convex, coxee marked with two oblique lines ;
those attached to the four anterior segments square, those to the three poste-
rior segments subtriangular and distant from each other; terminal segment
of the pleon triangular, smooth on its upper side, with the lateral margin
slightly dilated ; inner plate of the lateral appendages emarginate near the
extremity of its outer edge.

Length, 14 to nearly 2 inches.

Oniscus psora. Pennant, Brit. Zool. vol. iv., pl. 18, f. 1, 1777 (certe).
Higa emarginata. Leacn, Dictionn, Sci. Nat. xii. p. 349. Trans. Linn.
Soc. xi. p. 870. Suppl. Enc. Brit. 1, 428, pl. 22.
SaMOUELLE, Ent. Compend. p. 109. Dxrsmargst,
Crust. p. 305, pl. 47, f. 4, 5. Minne Epwarps,

Crust. iii., p. 240, Cuvier, Régne An. (Ed. Crochard),
Crust. pl. 67, £. 1.

Tuts species is distinguished at once by the somewhat
triangular form of the terminal segment of the tail, which

284 GID.

is flat on its upper surface and destitute of the carinz
observable in the other British species; its sides are
rather dilated at the base and somewhat recurved. The
animal is oval and convex ; the eyes large and lateral, with
many hexagonal facets; those, however, of the external
margin have their outer edge circular (a peculiarity now
ascertained to occur in the hexagonal structure of the
hive bee, which has lately been the cause of considerable
discussion among Entomologists). In our figure, a, the
third or right-hand row of facets is the external one.
The upper antenne are short, with a ten-jointed flagel-
lum, whilst the lower ones have the same part formed of
about eighteen articulations. The palpiform appendage
of the mandible is very slender and terminated by a
short thin and curved hook-like joint. The three an-
terior pairs of legs are strong and terminated by power-
ful hooked fingers; the middle joints in the first pair are
very short, but in the third pair the second and third
joints are armed with small conical tubercles; the four
posterior pairs of legs are longer and more slender, the
under edge of the terminal joints being spinose, the
spines being set in transverse rows. The lateral appen-
dages of the tail are narrow and of nearly equal size, the
inner plate of each pair being strongly emarginate on its
outer margin near the extremity, which is ciliated. In
one sex these organs are accompanied on the inner edge
by an elongated conical horny plate, represented in our
middle left-hand figure.*

Although the species was introduced by Samouelle
into his work on British species (no locality, however,

* Tn our principal figure of this species the articulation at the base of this
narrow plate has been accidentally omitted, giving to the fifth segment of the
tail the appearance of being produced on each side of the terminal joint
into a long narrow point.

GA PSORA. 285

being given), it is omitted by Mr. A. White from his
Catalogue of British Crustacea. Dr. Leach (the chief
authority for Samouelle’s work), indeed, stated in his
description of the species “ localité inconnue”’ (a specimen
has, however, since been received by the British Museum
from Iceland, from Mr. Drewsen), so that, except for
the unnecessary doubt expressed by Leach in his refe-
rence to Pennant’s Oniscus psora,* there is no recorded
authority for its insertion in the British list. We are
enabled, however, to introduce it unquestionably on the
faith of a fine specimen in the Bell collection (now at
Oxford, obtained at Scarborough by Mr. Bean, by whom
it was presented, with other interesting species from
that locality, to Professor Bell). This specimen has
supplied the figures at the head of this description.
The Hope collection also possesses a specimen from
Nova Scotia, and we have received it recently from
Mr. Gregor, who dredged it in the Moray Frith.

* Although unquestionably this is the On. psora of Pennant, it is doubtful
whether it be identical with the species so named by previous authors.

286 HGIDA.

ISOPODA. 44GI Di.
NORMALIA.

AGA MONOPHTHALMA.

Specific character. Oval, convex, eyes very large, uniting dorsally, ex-
tending obliquely backwards, the anterior margin of the first segment of the
pereion being deeply incised on each side for their reception, terminal segment
of the pleon flat, nearly semicircular, with a central carina terminating in a

point.
Length, 2 inches.
Aga monophthalna. Jounston, in Loudon’s Mag. Nat. Hist. vii.
p. 233, f. 43.

Rocinela monophthalma, Mine Epwarps, Crust. iii. p. 244. Wuirs,
B. M. Cat. Brit. Crust. p. 80. Pop. Hist.
Brit. Crust. p. 252, pl. xiv. f. 7. Gossk, Man.
Mar. Zool. 1, fig. 233.

THE animal is oval, of a pale brown colour, approach-
ing to fleshy red, and when alive tinged with purple,
dotted all over with numerous punctures. The upper
antenne are very short, the two basal joints much
dilated, forming together a broad movable plate; the
flagellum is setaceous, the lower antennz more than twice
the length of the superior, the three basal joints short
and unequal, the flagellum multiarticulate. The head is
almost entirely occupied by the large oblong eyes, which

EGA MONOPHTHALMA. 287

coalesce dorsally and centrally ; they are reticulated and
extend obliquely backwards, leaving a small point pro-
jecting anteriorly between the base of the upper antennz
and a small central triangular space behind. The inferior
antenne are separated at the base by a small oblong
concave plate or labrum. The seven segments of the
body are nearly equal in size, marked with a faint line
across the middle; their sides are furnished with strong
coxe pointed posteriorly, and with two slight ridges down
the middle. The first three pairs of legs are directed
forwards; they are robust, and furnished with strong
curved claw-like fingers; the four posterior pairs of
legs are longer and much more slender, with the joints
nearly equal and spinose, terminated by curved fingers.
The tail is formed of six segments, of which the five
first are short and equal, and the terminal one broad,
oblong, roughish, depressed, with astrong keel down the
centre ending in a short mucro; the margins of these
segments are minutely spinose ; on each side of the ter-
minal segment is a pair of foliaceous plates articulated
to a movable, acutely pointed, somewhat triangular pro-
cess; the inner plate is wedge-shaped and the outer one
oblong ; both are densely ciliated round the edge.

Dr. Johnston, whose detailed description is slightly
abridged above, adds that this species swims with rapidity
by the aid of its ‘‘ caudal fins,” and when it comes in
contact with a solid body it clasps against it and adheres
tenaciously. His specimens were taken adhering to large
cod-fish, of which it is probable they are the “ pedicular
parasites ;” but, unlike some of their race, they appear to
be very rare, at least in Berwick Bay, as he could only
procure three individuals, and the fishermen had neyer
observed them before.

Dr. Johnston also described and figured as a variety of

288 AGIDA,

the other sex a smaller specimen (12 inch long), having
the two basal joints of the upper antenne not dispro-
portionably enlarged, and the last large segment of the
tail emarginate-truncate, with a shallow furrow down the
centre, and two obtuse raised keels at its sides. In other
respects no difference appeared to exist. Except that
the eyes in the figure of this smaller individual are
represented as being of the same size as in the larger
ones (uniting in the centre of the forehead), we should
have referred it to Dr. Leach’s ga bicarinata, or more
probably to 4. tridens, with the central tooth of the tail
plate worn away (the eyes being large, as in that species).
Dr. Johnston, however, regarded it as belonging to the
same species as the larger individuals, and probably the
male of it, considering the dilatation of the basal joints
of the upper antennee as a sexual character, or one de-
pendent on age (and of insufficient value, therefore, to
be ranked among the characters which are seized upon
to divide tribes and families from each other), and also
that the conformation of the terminal segment of the
tail is not sufficient to discriminate species, as Dr. Leach
seems to have believed, ‘‘for his specific characters em-
brace no other part,” at least in the species of Aiga.
Unfortunately the comparative rarity of these parasites
does not yet allow us to determine this point.

The individual of this species described by our late
friend Dr. George Johnston was taken in Berwick Bay
on a cod-fish, and is preserved in the British Museum,
which also contains another specimen from the Northum-
berland coast, presented by Mr. R. House.

There are also British specimens of unnoticed locality in
the Hopeian collection ; and we have received them from
Shetland, from the Rev. A. M. Norman, who also records
it from the Moray Frith.

ROCINELA. 289

ISOPODA. AGIDA,
NORMALIA.

Genus—ROCINELA. = (Leach.)

Generic character. Tyes very large and convex, converging
anteriorly and nearly uniting in the middle of the forehead,
which is produced into a conical point concealing the base of
the upper antenne; first and second joints of the latter
cylindrical and much more slender than those of the lower
antennz, which are nearly one-third of the length of the body.

As our generic and specific descriptions are made from
Dr. Leach’s original type of R. Danmoniensis (the only
species which he inserted in the genus), we are able to
ascertain that M. Milne Edwards has misconceived
Leach’s views (which is not indeed surprising, as the very
short and unsatisfactory descriptions given by the latter
would scarcely afford a definite idea of its characters).
We consequently find that the genus thus named in M.
Milne Edwards’s great work consists of species of AXga,
with the eyes confluent and the basal joints of the upper
antennee rather more slender than in the typical Mige ;
but when we take into consideration, that the front of
the head in Leach’s type is produced into an obtuse
conical point projecting over the base of the upper an-
tennz, which are much more slender than the base of the
lower antenne, the latter being also more than one-fourth
of the length of the entire animal; that the pleon is as
wide as the pereion, the anterior segment being, however,
very short, and abbreviated at the sides, which neverthe-
less terminate in an acute point; and that the three fol-

VOL. II. U

290 AGIDA,

lowing joints of the pleon are large and broad, the
posterior lateral angles being produced into a curved and
acute point,—we shall be convinced that Rocinela Danmo-
niensis is the type of a distinct genus, and that Alga
monophthalma of Johnston, which M. Milne Edwards,
followed by Mr. A. White, introduces into the genus
Rocinela on account of the large size of the eyes, ought to
be referred to the genus #ga. ‘This opinion is confirmed
by the descriptions of the mouth-organs given by M. Milne
Edwards in the Crochard edition of the “ Régne Animal”
of the species which he terms Rocinela ophthalmica (giving
erroneously Leach as the author of the species), which
prove that that species is in fact an Atga, differing only
from Alga emarginata in the apparent soldering together
of the two terminal joints of the foot-jaws.

ROCINELA DANMONIENSIS. 291

ISOPODA, AGI DA.
NORMALIA.

ROCINELA DANMONIENSIS.

Specific character. Elongate-ovate ; eyes converging anteriorly, large,
nearly joining dorsally; basal joints of the upper antenne subcylin-
drical ; coxa (especially of the three posterior pairs of pereiopoda) prominent,
elongate-ovate, and pointed ; second, third, and fourth segments of the pleon

sickle-shaped and laterally produced.

Length, one inch.

Rocinela Danmoniensis. Leacu, Dict. Sci. Nat. xii. p. 349. Dusmarest,
Crust. p. 304. Murine Epwarps, Crust. iii.
p. 244. Wurrtr, Cat. Brit. Crust. p. 80. Pop.
Hist. Brit. Crust. p. 352.

Tuts species has hitherto been known only by Dr.
Leach’s original typical specimen taken half a century ago
in Plymouth Sound, preserved in the British Museum,
which has supplied the materials for the figures given at
the head of this description. It was described by Leach

as being ‘fen si mauvais état qu’il est impossible d’en
U2

292 GIDE.

faire une description specifique.”’ The posterior segment
of the tail is in fact destroyed, but the remainder of the
body sufficiently proves its complete distinction from any
other known British species. It is more elongate in
form than the species of Alga, and the two basal joints
of the upper antenne are thin and subcylindric, inserted
beneath the conically anteriorly produced middle of the
anterior margin of the head (the flagellum is destroyed).
The lower antenne are nearly one-third of the length
of the body, with a stout flagellum, consisting of about
thirteen articulations. ‘They are inserted close together,
and not separated by a ridge or scutcheon-shaped piece.
The eyes are of large size, converging above and nearly
uniting in front; each eye consists of nine rows of
facets, the middle or longest row containing thirteen
lenses. The palpiform appendage of the mandibles is
slender and three-jointed, the second joint thickened at
the tip and furnished with ten setz set on at right angles ;
the terminal joint is about two-thirds of the length of
the middle one, and terminated by a strong bristle, and
about seventeen short sete on its inner edge. The
lateral margins of the segments of the body (especially the
three posterior) are prominent and distinct, each being
produced behind into a sharp point (our upper left-hand
figure L to @ represents the four posterior segments of the
body and the two anterior ones of the tail seen laterally).
The terminal segments are traversed with a slightly ele-
vated carina; the legs are rather longer than in the species
of Aiga; the three anterior pairs are strong, with the
hand and wrist armed with a few short strong spines, and
the finger unguiculated, having the base dilated so as
almost to resemble a separate joint. The tail is as wide
as the body; the anterior segment is narrower than the
following, and very short, the sides ending in acute spines ;

ROCINELA DANMONIENSIS. 298

the three following segments are much larger and wider,
with the sides ending in acute recurved processes; the
fifth segment is as long as the preceding, but abbreviated
at each side, and the sixth is obtusely triangular.

We have received it from Polperro, where it was taken
by Mr. Loughrin, and there are specimens in the British
Museum from Ireland that have the caudal termination
more pointed than in our figure.

294 EGIDA,

ISOPODA. AAGIDA.
NORMALIA.

Genus—CIROLANA. (Leach.)

Generic character. Pereiopoda formed for progression, each
terminated by a slender nearly straight dactylos ; lower antennee
long; superior short, cylindrical; pleon formed of six distinct
segments; eyes small, granulated; head with submarginal
channels.

Tue animal is elongated and cylindrical-ovate; the
head is semicircular (owing to the deep emargination of
the following segment), with a minute triangle interposed
between the base of the upper antennz ; it is also marked
with an impressed line on each side near the outer orbit
of the eyes, and another finely impressed line runs closely
parallel with the anterior margin. The eyes are small,
but strongly granulated. The upper antenne are scarcely
more than half the length of the head, the two basal
joints broad and rather flat, the flagellum small, conical,
and with about ten articulations ; the upper antennz are
inserted beneath the latter ; the two basal joints are short ;
the third, fourth, and fifth more elongated, and the flagel-
lum is long and slender, composed of more than thirty
articuli, extending as far as the third or fourth segment
of the body; this lower pair of antennz are separated
at the base by a narrow elevated ridge, arising from a
small triangular piece which rests upon the front margin
of the transverse emarginate labrum.

Careful figures of the mouth-organs of C. hirtipes are
given by M. Milne Edwards in the Crochard edition of
the “ Réegne Animal.”

The mandibles are strong, angulated beyond the

CIROLANA, 295

middle, with several powerful acute teeth and an inner
movable lobe; the palpiform appendage is long, three-
jointed, and bent over the base of the lower antenne.
The pair of foot-jaws are moderately strong, composed
of six nearly equal-sized joints, deeply ciliated along
the inner edge; the first pair of maxille are triangular,
with the extremity narrowed, bearing an inner lobe of
the same length as the extremity of the organ. The
second pair of maxille are larger, stronger, and exarticu-
late, with the extremity curved and acute, furnished near
the base of the inner margin with a small movable
quadrate lobe, the inner margin itself armed with strong
bristles. The tail is not quite so broad as the body, with
the four basal segments of equal size, transverse, the
fifth as long as the preceding, but abbreviated on each
side, with the posterior margin straight, and not arched
as in the preceding segments. The last segment of the
tail forms a large triangular smooth plate, on the outer
anterior sides of which are affixed the lateral appen-
dages, of which the inner plate is the larger: they do not
extend beyond the extremity of the terminal segment.

296 EGIDA.

ISOPODA. AGIDA.
NORMALIA.

CIROLANA CRANCHII.

Specific character. Animal subcylindrico-ovate, smooth, finely punctured ;
segments with a slender pale line on the posterior margins, terminal segment
of the pleon triangular, slightly rounded at the extremity, inner plate of the
posterior appendages of the pleon larger than the outer, rather obliquely
truncate, legs slightly spined.

Length, three-fifths of an inch.

Cirolana Cranchii. Lxeacu, Dictionn. Sci. Nat. xii. p. 347. DEsMAREST,
Cons. Crust. p. 303. Minne Epwarps, Crust. iii.
p. 236. Wuitr, B. M. Cat. Brit. Crust. p. 79.
Pop. Hist. Brit. Crust. p. 249, pl. xiv. f£. 3.
GossE, Man, Mar. Zool. i. fig. 230.

Tue preservation of Dr. Leach’s typical specimen of
this species, having the name Cranchii still attached to it
in his small and very neat hand-writing, enables us to
clear up the short and unsatisfactory descriptions of it

given by M. Milne Edwards and A. White. The former

CIROLANA CRANCHII. 297

confines his specific description to four lines, given as a
quotation from Leach : ‘‘ Corps lisse ponctué ; le dernier
article de abdomen triangulaire, arrondi a son extré-
mité, lame externe des derniéres fausses pates plus grande et
plus large que Vinterne ; cette derniére tronquée a son eatré-
mité.”* Leach’s description is, however, confined to the
pereion and last joint of the pleon, and M. Milne Edwards
appears to have intercalated the latter portion of his
characters from Leach’s general observations on the third
race of the Cymothoade (comprising the genera Eury-
dice, Nelocira, and Cirolana): ‘‘ dans ces trois genres la
petite lame ventrale postérieure externe est plus grande
et plus large que l’intérieure.” In Eurydice, however, as
well as in the only species of Cirolana described by
Leach, the inner plate is considerably the larger, its
inner margin being somewhat obliquely truncate, whilst
the outer plate is the smaller, and is more or less pointed.
Mr. A. White unintelligibly says, ‘‘small plates of the
posterior ventral appendages larger and wider than the
inner.” As will be seen in our lower left-hand figure v at
the head of this species, the outer plate (at the right side
of the figure) is small and elongate-conic, the inner plate
much larger, and somewhat obliquely truncate, whilst the
basal portion is furnished with a conical point, extending
half the length of the inner plate. The appendages as
well as the edges of the terminal segment of the tail are
strongly fringed with sete. The legs are but slightly
spinose and rather slender. The ridge between the base
of the lower antennz is not so narrow as in C. spinipes.

* M. Milne Edwards, in his generic character of Cirolana, describes the two
plates of these lateral caudal appendages as being ‘‘a peu prés de méme
grandeur,” but in his description of C. hirtipes he says that ‘‘1’interne est
plus large que l’externe,” and in C. elongata ‘‘ lame externe trés petite, l’in-
terne grande et arrondie au bout.”

298 MGIDA.

The original specimens of this species were forwarded
to Dr. Leach from Falmouth (Cornwall), by Mr.
J. Cranch. They have afforded the materials for our
figure and description, and we have dredged a specimen,
near the Knapbuoy, outside the Plymouth Breakwater,
in about six fathoms of water. We have also received it
from Mr. D. Robertson, of Glasgow, taken at Cumbrae.

The accompanying vignette of Dutch fishing boats is
from a painting in the possession of J. Thackeray, Esq.,
of Amo Vale, Nottinghamshire.

DUTCH FISHING BOATS.

CIROLANA SPINIPES. 299

ISOPODA. AAGIDA.
NORMALIA.

CIROLANA SPINIPES.

Specific character. Cephalon wider than long, with a curved incised line
on each side parallel with the lateral margin. Pereion very convex, smooth.
Pereiopoda strong and broad, armed with numerous spines; inner ramus
of the posterior pair of pleopoda (uropoda) larger than the outer, elongate-
ovate, acute at the tip, basal joint produced into a short subconical point.

Length, nearly one inch.

Cirolana hirtipes? Mitne Epwarps, Crust. iii. p. 286, t. 31, f. 25.
Cuvirr, Régne Animal (Hdit. Crochard), Crust.
t. 67, f. 62 W. THompson, in Ann. Nat. Hist.
xx, p. 246. Warts, B. M. Cat. Brit. Crust.
p. 79. Pop. Hist. Brit. Crust. p. 850.

THIS species is at once distinguished from the typical
C. Cranchii—the only one hitherto described as a native
of Northern climates—by its robust form, convex glossy
body, thick spinose legs, and by the shortness of the

300 GID.

produced inner angle of the basal joint of the lateral
caudal appendages.

This last character, as well as the diversity of habitat,
induce us to consider our second native species as dis-
tinct from the C. spinipes of Milne Edwards, who gives
the Cape of Good Hope as its locality, with which it
was considered as identical by Mr. A. White.

The general form is elongate-ovate, somewhat com-
pressed at the sides, giving the body a convex appear-
ance ; it is very glossy and impunctate ; the pleon is not
quite so broad as the seventh segment of the pereion.
The head is large, wider than long (in which respect
also the animal differs from C. spinipes as described by
Milne Edwards), somewhat rounded in front, marked at
each side with the impressed line which appears to be
a character of the genus. The upper antenne are very
short, composed of two small square flattened joints,
with a short conical ten-jointed flagellum. The lower
antennee are nearly half the length of the body, com-
posed of two very short and three long basal joints, and
a long and slender flagellum, consisting of about twenty-
four articuli. These antenne are separated from each
other at the base (when seen from beneath) by a narrow
elevated ridge, below which is a broad, short upper lip,
with the sides rounded, and the middle of the free margin
slightly emarginate; the mandibles are very robust, fur-
nished with a triarticulate palpiform appendage (one of
which is seen in our lower left-hand figure at d’), The
legs are strong, with, especially, the middle joints broad,
and subtriangular, their upper angle being produced
into a point; on the outside they are armed with numer-
ous strong bristles or slender spines, a character which
appears to us not to accord with Milne Edwards’s de-
scription, “ pates tres-poilues,” of his C. hirtipes. The

CIROLANA SPINIPES. 301

terminal segment of the pleon is as long as the preceding
three segments united; it is somewhat triangular, with
the lateral margins rounded and the extremity rather
pointed; the lateral appendages of this segment are
thin, the inner plate larger than the outer, elongate-
ovate, scarcely pointed at the tip ; and the basal joint is
prolonged into a short triangular point, corresponding
with the “ grande dent lamelleuse et acerée qui atteint
le milieu des lames terminales” of C. hirtipes as described
by Milne Edwards.

A specimen of this species was first noticed by the
late Mr. W. Thompson, which was procured in a fishing
boat in Dublin Bay, by Mr. T. W. Warren, in 1847.
This specimen has furnished the figures at the head of
this description. Another specimen is in the British
Museum, from Belfast Bay, taken out of a holibut, and
several specimens are in the Hopeian collection, at
Oxford, one of which is labelled “ Brighton,” and
another was, we believe, taken off the Yorkshire coast.
We have also received it from the Moray Frith, where it
was taken by Mr. Gregor.

IMG Hesse,sAnnasdes: Se: Nat. volsive p, 257, 1860
describes several species of this genus that he has taken
burrowing in the sand on the coast of Britanny.

302 FEGIDA,

ISOPODA. AGIDA.
NORMALIA.

Genus—CONILERA. (Leach.)

Generic character. Subcylindrical, pleon as wide as the ter-
minal segments of the pereion, four anterior pairs of legs
strong, three hind pairs slender; maxillipeds with the three
terminal joints broad and flat, outer pleopoda divided into two
nearly equal-sized joints.

THE very short characters given by Leach of this genus,
and by Montagu of the only known species, having been
insufficient to afford any true idea of the relations of the
type, we are happy in being able to furnish detailed
figures of the chief external organs.

The animal is nearly cylindrical in form, with the sides
of the body nearly parallel, the head semi-oval, deeply
immersed in the first large segment of the body, of
which the anterior lateral angles are considerably ad-
vanced ; the tail is composed of four nearly equal-sized,
short basal segments (the first more or less concealed
beneath the preceding), followed by the fifth, which is
contracted at the sides, whilst the sixth is elongate-
triangular.

The upper antennz are short, with the basal joints
subcylindrical ; the second pair are about twice the length
of the preceding, separated at the base by a narrow
ridge; the labrum is transverse, rounded at the anterior
angles. The mandibles are tridentate at the tips, with a
slender serrated inner movable lobe, and a three-jointed
palpiform appendage. The maxillipedes or foot-jaws are

CONILERA. 303

six-jointed, flat, with the three terminal joints very broad,
and gradually decreasing in size. The first pair of
maxilla are terminated by two somewhat triangular
ciliated lobes; the second pair of maxillz are trilobed,
the outer lobe subtriangular and armed with a row of
strong bristles; the innermost lobe is compound, and
terminated by three small appendages (fig. f”). The four
anterior pairs of legs are robust, with the middle joints
produced above into a strong angle. The three hind
pairs are much more slender, and terminated by a very
minute hook. The anterior pair of pleopoda are formed
of two nearly equal joints, whilst the large lateral appen-
dages of the last segment of the tail have the outer edges
of the two divisions strongly notched.

304: EHGIDA.

ISOPODA. AAGIDA.
NORMALIA.

CONILERA CYLINDRACEA.

Specific character. Upper antennez reaching to the eyes, lower antennze
reaching to half the length of the first segment cf the body, inner division
of the uropoda much larger than the outer, ovate, with the extremity
pointed and the outer lateral margin notched, basal joint not having its
inner angle produced into a point.

Length, about three-quarters of an inch.

Oniscus cylindraceus. Mownt., Trans. Linn. Soe. vii. p. 71, t. 6, f. 8.

Conilera cylindracea. Wuittr, B. M. Cat. Brit. Crust. p. 80. Pop.
Hist. Brit; Crust. p. 252, “ply save ehaoe
GossE, Man. Mar. Zool. fig. 234.

Conilera Montagui. Leacu, Trans. Linn. Soc. xi. p. 370. Dictionn.
Sci. Nat. xii. p. 349.. DeEsmarest, Cons.
Crust. p. 305. Minne Epwarps, Crust. iii.
p. 242. Waits, B. M. Cat. Brit. Crust. p. 80.

Anthura cylindrica. Leacu, Trans, Linn, Soc. xi. p. 366. Wuurz,
B. M. Cat. Brit. Crust. p. 67.

CONILERA CYLINDRACEA, 305

THE whole upper surface of this animal is smooth, glossy
and impunctate, of a pale yellow colour, clouded with
cinereous on the sides. The eyes are small and distant
apart; the antenne short, the upper not extending
beyond the eyes, composed of four rather strong sub-
cylindrical basal joints, and a flagellum of about seven
articuli; the lower antennz (separated from each other
by a narrow raised ridge) are rather more than twice
the length of the upper pair; they consist of four
short basal joints, a fifth slender joint, and a flagellum
with about twelve articuli. The labrum is trans-
verse, with the anterior angles rounded, and the middle
of the free margin slightly emarginate. The man-
dibles are robust and horny, with the apex incurved
and three-toothed, the middle of the inner margin fur-
nished with a slender movable appendage slightly ser-
rated on its upper edge; the foot-jaws are broad, shutting
the mouth from below, six-jointed, the three terminal
joints broad and flat, with their outer margins setose.
The first pair of maxilla are composed of a broad basal
joint terminated by two somewhat conical lobes, of which
the outer is divided into two parts by an oblique articu-
lation. The second pair of maxillz (represented more
magnified than the preceding mouth-organs) are termi-
nated by three lobes, of which the outermost is largest,
somewhat triangular, and furnished with strong bristles
on its inner edge; the middle lobe is a slender simple
piece, but the innermost lobe is much more complicated,
terminated by three small pieces, of which the outer is
slender, curved, and setose at the tip; the two inner lobes
are of equal size, conical, and strongly and transversely
verticillated across their centre. The three fore pairs
of legs are short and very robust, with the middle
joints broad, flattened, and produced into an angle on

VOL. Il. X

306 ZEGID A.

the outside and serrated on the inside. The fourth
pair of legs are intermediate in size, between the three
fore and three hind pairs, which latter are slender ;
all the legs are terminated by a small hook-like finger,
which appears to be articulated at its tip in the hind
legs.

The terminal segment of the tail is obconical, with
the sides slightly curved and the extremity rather
rounded. The anterior pair of pleopoda are strong, and
form an operculum, of which the basal joint is large and
oblong, and the two terminal divisions unequal, the
inner one being the larger, with its inner edge straight,
whilst the outer one is more ovate; the lateral appen-
dages are also unequal, the inner lobe being the larger
and ovate, with its apex acute, the outer margin beyond
the middle somewhat notched and spinose.

It will be seen by a comparison of our description and
figures of the parts of the mouth with those of the genus
Cirolana, given in the Crochard edition of the ‘ Régne
Animal,” that this animal is closely allied to the last-
named genus, and that it has no other relation with
Anthura than its narrow cylindrical form.

The species was first obtained by Colonel Montagu on
the eoast of Devonshire ; we have procured it by dredging
in the Sound, and in six fathoms near the Knap Buoy, and
from trawlers off Plymouth, and have received it from
Mr. Loughrin from Polperro, and from the Frith of
Clyde, taken by the Rev. A. M. Norman, Dr. Lukis, of
Guernsey, took upwards of a dozen specimens feeding
together within the orbit of the eye of a whiting, the eye-
ball of the fish being nearly detached from the surround-
ing parts. The fish did not seem to be out of condition,
although the parasites must have been there some time,
as they were remarkably blanched.

EURYDICE. 307

ISOPODA. 4iGIDZ.
NORMALIA.

Genus—EURYDICE. (Leach.)
SLABBERINA. (Van Beneden.)

Elongate-ovate, moderately convex ; upper antenne very
short, cylindrical ; lower antenne long, with a multiarticulate
slender flagellum; legs smali; uropoda with the inner division
larger than the outer, and hatchet-shaped.

Tue only two characters given by Dr. Leach of this
genus, namely, the ‘‘ abdomen composé de 5 articles,”
and ‘‘ yeux lisses,” which are described as separating it
from Nelocira (in which the pleon is described as having
five segments, and the eyes being granular), and also
from Cirolana (in which the pleon has six segments,
the eyes being also granular), are unsatisfactory, and
have induced M. Milne Edwards to unite Nelocira with
Eurydice, especially as the figure given by Desmarest of
the former of these two genera represents it with a six-
jointed tail; whilst Van Beneden expressly says that the
eyes are distinctly faceted in the animal, which he has
described and figured under the name of S/abberina agata,
and which is certainly identical with the Hurydice pul-
chra of Leach.

Van Beneden, moreover, represents the tail as formed
of a large exarticulate mass, in which the five anterior
segments are only indicated by partial longitudinal mark-
ings on the skin, followed by a sixth narrow segment
and a seventh large terminal semi-ovate one.

He also describes and figures the upper antenne as

Kee

308 EHGIDA.

composed of only three joints. A very careful exami-
nation of the species has, however, shown that in all these
characters Van Beneden has fallen into some unaccount-
able error. The eyes under a strong lens are not faceted.
The seventh or last segment of the body is considerably
shorter than the sixth; the first segment of the tail is
still shorter and abbreviated at the sides, whereas the
second, third, fourth, and fifth segments are of equal size,
perfectly distinct in their articulations, and with the
posterior-lateral angles of each produced into an acute
point like the terminal segments of the body; the sixth
or terminal segment of the tail is of large size, semi-
ovate, and has a deep transverse impression near the base
(this impression is not represented in our outline figure,
but it seems to correspond with Van Beneden’s narrow
penultimate segment).

The upper antenne are very short and cylindrical,
composed of three basal joints, arising from a fixed base,
the third being as long as the two preceding joints taken
together, followed by three small articuli, of which the
last is very minute, and almost concealed by terminal
seta. The lower antenne are about two-thirds of the
length of the animal, having five basal joints, thicker
than the remainder, extending to the extremity of the
upper antenne, followed by a long very slender flagel-
lum, composed of a great number of minute articuli.
The mandibles are horny, with several conical teeth at
the tip, and with a slender movable blade attached to
the inner margin, having a finely serrated upper edge.
They externally bear a slender three-jointed palpiform
appendage.

The foot-jaws are six-jointed, the joints of moderate
width, the second having the inner apical angles pro-
duced, the remainder being armed with bristles on the

EURYDICE. 309

inner edge ; the outer maxille (e) are apparently formed
of three closely soldered joints, indicated by bristles, on
the inner edge, the second and third joints being pro-
duced on the inner margin. The inner maxille are
bilobed, the outer division broader than that of the
outer pair, and armed with stronger bristles, the inner
division minute and armed with bristles set on at right
angles.

The four anterior pairs of legs are rather shorter than
the three posterior ones, the former being armed with
short spines on the lower edge, whilst the hind ones are
smooth, having the outer angles of the middle joints
conically produced and setose. The uropoda, or lateral
appendages of the tail, arise on each side from a broad
basal joint, the inner division being larger than the
outer and obliquely truncate at its extremity; both
having ciliated margins.

310 GIDE.

TSOPODA. AGIDA.
NORMALIA.

EURYDICE PULCHRA.

Specific character. Eyes not faceted, body semi-transparent, pale ashy
colour, figured symmetrically with dark markings, resembling the star-
like spots in agate, basal segments of the pleon with a large transverse
mark on each side formed of small black lines.

Length, one-quarter of an inch.

A gaat Pissebet. (Ontscus) SuaBBeR, Naturk. Verlust. p. 149, pl. 17,
Poles

Burydice pulchra. Leacu, Trans. Linn. Soe. xi. p. 370. Dictionn. Sci.
Nat. xii. p. 347. Suppl. Enc. Brit. i. p. 428.
SAMOUELLE, Entom. Compend. p. 109. Drsma-
REST, Cons. Crust. p. 3802. Minne Epwarps,
Crust. iii, p. 238. W. Tuompson, in Ann. Nat.
Hist. xx. p. 240. Wuuitr, B. M. Cat. Crust.
p. 79. Pop. Hist. Brit. Crust. p. 250. Gossx,
Man. Mar. Zool. i. fig. 231. Hrssr, Observations
biologiques sur quelques Crust. des Cotes de Bré-
tagne, Ann. des Sc. Nat. v. p. 242 (1866.)

Slabberina agaia. Van Brnupren, Recherches sur la Faune litt. Belg.
p. 88, pl. 15 (1861).

EURYDICE PULCHRA. 311

Tuts beautiful little species was first described and
figured by Slabber, in his fine microscopical work
above referred to. His article on it has, however, been
overlooked by all carcinologists, except Van Beneden,
who has published a detailed account of it in his re-
searches on the littoral fauna of Belgium, and who
remarks that no naturalist had reobserved Slabber’s
animal; this is not indeed surprising, since the de-
scription of it by Leach (which has hitherto served for
all subsequent writers on this tribe) is so short and
unsatisfactory as not to be readily recognized.

The body is smooth and of a pale grey colour, each
segment marked with about eight or ten black dots
formed of delicate radiating lines, closely resembling the
markings upon certain varieties of agate; these spots
are arranged transversely and with a great amount of
regularity upon the succeeding segments; each of the
basal joints of the tail, on the other hand, is marked with
two transverse spots formed of a series of very fine
black lines; the large terminal segment is transversely
depressed near the base; the tail is furnished on its
underside with five pairs of foliaceous membranous plates,
each articulated across the middle, the basal division
being almost square, and the apical division nearly semi-
circular, the latter fringed all round with about twenty-
five very fine hairs, each of which is fringed along its
whole length with most delicate cilia; the outer pair of
the caudal plates do not perform the duty of an opercu-
lum as in the Idotea, and the sides of the terminal
segment are furnished with lateral appendages, the outer
division of each of which is smaller than the inner por-
tion, which is obliquely truncate at its extremity, and
hatchet-shaped.

This species is found in small pools left by the re-

312 AGIDA.

tiring tide, where it swims about with the utmost celerity.
It is not difficult to keep it alive in confinement, Slabber
having kept one for nine days in the month of August.
It occurs on the coast of Devonshire, where it was taken
at Bantham by Dr. Leach, and in South Wales by our-
selves, on Loughor Marsh, and on a cuttlefish shell on
the beach in Caswell Bay, and Mr. W. Thompson
obtained it from Larne. Van Beneden states that he
only found it in summer; it was, however, taken at
Carrickfergus, by Mr. Hyndman, on the 17th of March,
1840.

M. Hesse has found it burrowing in sand on the coast
of Britanny. The Rev. A. M. Norman has sent it to us
from the coast of Northumberland and Durham, and
Mr. Walker of Brookfield, near Cheshire, writes us that
“ Corophium longicorne and Eurydice pulchra are the com-
monest crustacea in the Dee, at least at Bagillt, where
his observations have been made. ‘* The latter,” he says,
‘‘is a most savage little beast. If you are a moment
still in the water while bathing, dozens will fasten upon
you and nip most unpleasantly. I have had to jump into
the water again after coming out from bathing and splash
violently to get rid of the hosts that had stuck to me
while clinging to the side of the boat preparatory to
getting in. They continue to bite after you are out of
the water. I once put a wretched Hyperia which I
had taken from a Rhyzostoma, into a small bottle with
two Eurydices; the bloodthirsty little brutes attacked
him at once like tigers, and soon sucked his shell clean.”

ASELLIDA, 313

Tribe—LIBERATICA.

THE remainder of the aquatic Isopoda are free in
their habits, not residing as parasites on the bodies of
fishes or other sea animals. Their legs are consequently
not formed for prehension or attachment to their prey,
nor armed with a strong hook at the extremity, but, on
the contrary, they are slender, and generally of uniform
size and structure, and fitted for locomotion. They con-
stitute five families—Asellide, Munnopside, Arcturide,
Idoteide, and Spheromide.

Family—ASELLIDA.

THe animals composing this family are of a sub-
depressed form; and have not the posterior pair of
pleopoda developed into an operculum to the remainder
of the respiratory apparatus (in which respect they differ
from the Ldoteide and Arcturide, whilst the Spheromide
have the body very convex, and capable of being rolled
up into a more or less perfect ball). The mandibles
are armed with a palpiform three-jointed appendage ; the
first two or basal joints of the foot-jaws are strongly
produced on the inner margin, and the outer maxille
terminated by three large flattened membranous plates.

The genus Limnoria differs in several important re-
spects from the other genera of this family, and was in
fact considered by Dr. Leach to form a separate class
amongst his Cymothoades.

314 ASELLIDE.

ISOPODA. ASELLIDA.
NORMALIA.

Genus. JASRA. (Leach.)

Generic character. Upper antenne very short. Lower
antennze more than half the length of the animal. Legs uni-
form, slender. Pleon coalesced into one segment, furnished with
two minute subterminal uropoda. Pleopoda or branchial appen-
dages covered by a large plate occupying the entire under surface
of the pleon. Dactyla biunguiculate.

Tue small flattened species, which is the type of the
present geifus, is distinguished from the allied genera by
the minute upper antennze and terminal appendages to
the tail, the claws with which the moderately long slender
uniform feet are furnished at the tip, and especially the
very remarkable structure of the under surface of the
tail. ‘The body is considerably flattened, and elongate-
ovate (or narrow in some exotic species). The head is
not soldered to the following segment of the body; its
sides are rounded, having, like the segments of the body
and the tail, a thin Jateral margin. Its fore margin is
bi-emarginate, the antennz not having their basal joints
concealed, but arising within the emargination. The
upper or inner antennz are very small and four-jointed,
not extending to the third joint of the outer pair, which
are considerably more than half the length of the entire
animal, with the two basal joints short, the third twice
the length of the preceding, the fourth long and more
slender, but thickened towards the tip, followed by a
very long and slender multiarticulate flagellum. The

JRA. 315

mandibles are strong, horny, curved inwards at the tip,
and armed with several teeth, the lowest of which is
truncate. They are provided with a three-jointed palpi-
form appendage. The basal joint of the foot-jaws is
large and triangular, with the tip ciliated, followed by
five joints, of which the distal ones are the most slender.
The first pair of maxillz are furnished at the extremity
with three oval membranous plates, ciliated at their
extremities, the anterior one being the largest. The
second maxilla are composed of two branches, of which
the outer one is the larger, and armed at the tip with
strong bearded bristles.

The segments of the body are strongly marked by
lateral incisions, the sides being rounded, and the pos-
terior-lateral margins not produced into a point. The legs
are of moderate size, being nearly uniform both in length
and thickness, and terminated by two small hooks of
nearly equal size. The female carries between the base
of the legs an ovigerous pouch, composed of delicate
membranous plates, within which the young are deve-
loped. The tail consists of only a single plate, formed by
the coalescence of all the segments of the pleon, which is
semicircular (or semi-ovate) in form, and,in our British
species, with a small semicircular incision in the middle
of the posterior margin, within which are attached the
two very minute terminal appendages, each of which
consists of a square flat joint, supporting two extremely
minute conical plates, of which the outer one is almost
obsolete; the tips of these plates are furnished with
hairs. In J. Kréyerit the tail has two small semicircular
incisions, between which the centre is produced into a
small point, and the appendage on each side consists of a
small square basal joint, supporting two minute oval
plates.

316 ASELLIDA.

We have been under the necessity of sinking the
genus Jeridina of Milne Edwards since our discovery
that the “absence de la grande lame operculaire,” which
in Jera ‘‘remplace les premiéres fausses pates,” is a
sexual character. The type J. Nordmanni of Rathke
must, moreover, be removed from Janira, to which genus
it was referred by the last-named author, as it wants the
long styliform processes at the end of the tail.

The following vignette of Brighton Fishermen was
kindly done for this work by Mr. Jennings.

BRIGHTON FISHERMEN,

JEHRA ALBIFRONS. 317

TSOPODA., ASELLIDA.
NORMALIA,

JRA ALBIFRONS.

Specific character. Subovate, very depressed, sides of the cephalon, pereion,
and pleon margined. Colour cinereous, with the anterior margin of cephalon
whitish.

Length, about one-sixth of an inch.

Oniscus albifrons, | Montaau, MSS. in Brit. Mus.

Jera albifrons. Leacu, Edinb. Encycl. vii. p. 484. Trans. Linn. Soc.
xi. p. 373. Suppl. Enc. Brit. i, 428. SamovE ie,
Ent. Compend. p. 110. Dxrsmarust, Cons. p. 316.
Mitne Epwarps, Crust. iii. p. 150. W. Tompson,
in Ann. Nat. Hist. xx. p. 245. Wuuits, B. M. Cat.
Brit. Crust. p. 69. Pop. Hist. Brit. Crust. p. 231.
GossE, Man. Mar. Zool. i. fig. 243.

Jera nivalis ? Kroyer, Grénlands Amfipod. p. 75, pl. 4, fig. 2la—k.
Mitne Epwarps, O. C. p. 149.

Oniscus marinus? ©. Fasricrus, Fn. Greenl. p. 252, n. 229.

318 ASELLID&.

THE accompanying figure of this species has been made
from Colonel Montagu’s typical specimens, described by
Dr. Leach, in the British Museum. Not only do they
differ from the J. Krdyerii of Milne Edwards, from the
shores of La Vendée, in their much broader form, but
they agree in this respect with Kroéyer’s figure of J. nivalis,
from Greenland, whilst the description of the tail given by
Otho Fabricius of his Oniscus marinus (‘‘ cauda subciliata
et extremitate incisuram vix notabilem habens, de qua
styli duo brevissimi, acuti, distantes”’) seems also to
accord with other British species. Dr. Leach, indeed,
describes the eyes in his species as being ‘‘ placed close
together,” but this character neither agrees with the type
nor with the descriptions and figures of Kroyer and
M. Edwards. The upper surface of the body is flattened
and marked with irregularly impressed lines. The lower
or outer pair of antenne are considerably more than half
the length of the animal. The tail is much wider than
long, being nearly semicircular in form, having two
small impressed dots a little apart towards its basal por-
tion ; the centre of the caudal margin has a nearly semi-
circular notch, with the centre of the incision slightly
produced into an obtuse point, on each side of which are
implanted the minute uropoda.

The general colour is ashy, but very much varied in its
shades in dried specimens, with the front of the head
whitish.

Jera Hopeana of Costa (Faun. d. Regn. di Napoli fase.
83, tav. ili.) appears to us identical with the present
species, agreeing with it (contrary to Signor Costa’s
statement) in the position of the eyes; the only apparent
difference consisting in the equal size and apparently
three-articulated structure of the two appendages of the
minute terminal uropode.

JRA ALBIFRONS. 319

J. alhifrons probably occurs all round our coasts. We
have it recorded on the Devonshire and other coasts,
among sea-weeds and under stones, in many parts of the
British islands. It was found especially abundant in
crevices of rocks at half-tide near Falmouth, by Mr. W. P.
Cocks, and we have taken it abundantly beneath and
generally attached to the under surface of stones between
tide-marks in Plymouth Harbour, the flat surface of the
body enabling the animal to ensconce itself in very slight
crevices. The late Dr. Johnston also forwarded it to us
from the Berwickshire coast.

820 ASELLIDZ.

ISOPODA. ASELLIDA,
NORMALIA,

JHRA NORDMANNI.

Specific character. Broadly ovate ; sides of the segments strongly ciliated,
with hairs set on at right angles ; upper antenne four-jointed, terminal joint
not multiarticulate ; lower antennz not more than one-third of the length of
the animal, with the third joint not half the length of the following ; pleon
with a deep semicircular notch, within which the two small caudal appendages
are visible, extending very slightly beyond the margin.

Length, about one-sixth of an inch.

Janira Nordmanni. RatuxKe, in Mém. des Sav. Ktrang. de St. Petersb.
(Fauna der Krym.), t. iii. pl. 6, figs. 1—5, p. 388.
Jeridina Nordmanni.. Mrtnn Epwarps, H. N. Crust. iii. 150.

Tus small animal was arranged by its first describer,
Rathke, as a species of Janira; but that genus possesses
elongate appendages at the extremity of the body, as in
the common Asellus. Professor Milne Edwards accord-

JERA NORDMANNI. Sol

ingly removed it therefrom, and formed for its reception
a new genus, Je@ridina, in consequence of the branchial
apparatus on the underside of the tail not being covered
by a *‘ grande lame operculaire qui chez eux remplace les
premiéres fausses pates” (which had been given as the
generic distinction between Asellus and Jera). Having,
however, ascertained that this “ grande lame” is a sexual
distinction peculiar to the females, we are under the
necessity of referring the new species to the genus Jera,
with which it agrees in all its essential characters.

It is considerably broader than J. albifrous, the lateral
margins being very thin and dilated, as well as ciliated
with rather strong bristles set on at right angles, a
peculiarity of structure eminently fitted for enabling the
animal to reside in flat crevices, beneath stones, &c., in
situations often uncovered by the tide; the ciliation of
the sides of the body serving for the retention of the
fluid which supplies the material for respiration; just
as in many insects residing in occasionally submerged
situations under stones, it maintains a supply of air for
the like purpose. The head is deeply incised in front,
for the reception of the antenna, the inner pair of
which are very short, and four-jointed, the terminal joint
offering no apparent trace of articulation; the outer
antennze are not more than one-third of the length of
the animal, the third joint being only about twice the
length of the preceding, and not half as long as the
following joints, the flagellum is very slender and multi-
articulate. The terminal segment, or tail, is large and
semicircular, with a rather deep semicircular incision
at its extremity, within which are affixed the two caudal
appendages, consisting of a small oblong basal joint, at
the extremity of which are attached two small scales,
the outer one being extremely minute and conical, the

3

322 ASELLID®.

inner one large and oval, setose at the tip. The outer
ventral scales are free, forming together nearly a circle,
each divided into two nearly equal parts by a somewhat
diagonally-placed articulation ; at their base is attached,
in the males, two minute triangular plates and the
elongated male organ, which extends to the above-men-
tioned articulation. The legs are terminated by two
minute curved ungues.

Rathke obtained his specimens at Cape Parthenon, in
the Crimea, under stones; our specimens were taken at

Plymouth, and in Langland Bay, South Wales.

MUNNA. 3 rs

ISOPODA. ASELLIDA.
NORMALI4A.

Genus—MUNNA. § (Krdoyer.)

Male. Elongate, sublinear. Female. Broad, ovate.

First and seventh segments of the pereion shorter than the rest; cephalon
very broad and large, occupying nearly one-fifth of the whole length of
the animal. Eyes very large, fixed at the postero-lateral angles of the
cephalon, pedunculated, immovable. Upper antennze very short; lower
antenne very long. First pair of legs small and strong; the remainder
very long and slender, terminated by two small ungues. Pleon having all
the segments coalesced into a single elongate pear-shaped plate.

Tue large size of the head, together with the very pro-
minent, pedunculated (although not movable) eyes, which
stand out, in the males, considerably beyond the lateral
margin of the body, gives a very distinctive character to
this genus; and the great length of the lower antenna
and legs, giving the animals the appearance of one of
the Nymphonide, at once separates it from all the
other genera in the present family. The facets of the
eyes are large and hexagonal; the antenne are inserted
at a considerable distance apart (represented in our
lower left-hand outline in the woodcut of M. Kroyeri),
the upper pair consists of several very short joints,
followed by a long, slender portion, which is exarticulate
in M. Whiteana, but distinctly consists of three joints in
M. Kroyeri; this portion is terminated by two flattened
(and articulated ?) setae at the tip, at the base of
which are affixed two or three very minute joints,
observed only by us in M, Whiteana, and which constitute
the true flagellum. The lower antennz are very long,

¥ 32

324 ASELLID#.

exceeding the whole animal in their length, with a four
or five-jointed peduncle (of which the two last joints
are long and subequal), and a multiarticulate flagellum
half the length of the entire antenne. The segments of
the body are subequal in length, but the first and
seventh are often shorter than the rest: in the males,
the body is narrow, with the sides parallel; but in the
female, the outline of the animal is ovate, or pear-
shaped. The foot-jaws consist of a large basal joint,
armed at the base with an elongated triangular scale, and
produced on its inside into a flattened blade, rounded at
its extremity and ciliated, and followed by four distinct
joints, gradually becoming more slender, and furnished
with strong bristles at their distal extremities. The
mandibles are robust, and armed on the inner edge with
a strong molar tooth, and at the base, on the outside,
with a three-jointed palpiform appendage. The fore legs
are short but strong, and furnished with a subcheliform
hand, whilst the six remaining pairs of legs are very
long, and terminated by two long, slender, simple ungues.
The tail consists of a single piece, of a flattened ovate
form, narrower than the segments of the body. We
presume that in this genus the sexes are distinguished
by the same condition of the branchial plates as
we have above stated to occur in several of the other
genera of this family. Kroyer, in his characters of the
genus, says ‘unica infra lamina preditum tectoria,”
whilst H. Goodsir represents the ‘‘ abdominal plate,”
as he terms it, as composed of two long and narrow
pieces soldered together along their inner margins,
copied in our cut of M. Kroyeri ; but on referring to
Kroéyer’s original description, we perceive that it is
taken from the female of M. Boeckii, whilst H. Goodsiv’s
description is taken from a male animal.

MUNNA. 825

The eggs in this genus are carried in a large ovisac,
situated between the middle legs, and composed of four
large plates.

As it is very probable that Kroyer’s two species will
be discovered in our northern seas, we add his characters
of both.

Munna Fabric, Kr., abdomen ovale vel subellipticum,
aperte longius quam latum ; appendicibus caudalibus rudi-
mentariis sed sat distinctis. Annulus thoracicus sep-
timus sat distinctus.

Munna Boecku, Kr., abdomen capite aperte longius
subconicum non multo latius quam longum, appendi-
cibus caudalibus fere evanescentibus ; annulus thoracicus
septimus parum distinctus, sexto multo brevior.

The following vignette represents the rudimentary
uropoda of—1l. Munna Kroyert. 2. Munna Whiteana.
3. Leptaspidia brevipes.

326 ASELLIDA.

ISOPODA. ASELLIDA.
NORMALIA,

MUNNA KROYERI.

Specific character. Male with the eyes very prominent, extending con-
siderably beyond the pereion. Pereion setose. Pleon scarcely longer than
wide. Carpus of first pair of gnathopods thick, with strong spines on the
under edge, and two strong spurs at the tip beneath. Upper antenne ter-
minated by two long articulated sete, and a very minute flagellum.

Length, one line.

Munna Kréyert. Goovstr, Edinb. New Phil. Journ. xxxiii. p. 365, t. 6,
f. 6 (1842). W. Tompson in Ann. Nat. Hist. xx.
p. 247. Wuuirz, B. M. Cat. Brit. Crust. p. 70. Pop.
Hist. Brit. Crust. p. 231, pl. xiii. f. 3.

Tue male of this species has only hitherto been ob-
served. It has the ‘whole body very setose, and is of
an ochrey-brown colour, except the reticulated portion
of the eyes, which are black. The head is large, rounded
anteriorly, and slightly pointed in the middle. The ter-

MUNNA KROYERI, O27

minal joints of the foot-jaws are seen projecting in front
of the anterior edge, and they are always in motion. The
dorsal surface of the head is quite smooth, and the internal
or superior antennz arise from it within the margin, and
a little anterior to the eyes; they are composed of a
peduncle of three articulations, and of a double multi-
articulate setaceous portion, which arises from the last
joint of the peduncle: these are very slender, and
incline towards one another at their extremities; the
whole organ is equal in length to the two first joints of
the inferior antennee and the proximal half of the third
joint. The external antenne are much produced, being
considerably longer than the body; the peduncular
portion is composed of four joints; the setaceous flagel-
lum is multiarticulate; two large blood-vessels are seen
running through these organs. The eyes are Jarge and
pedunculated, but quite immovable; the reticulated
portion is small, and is almost altogether confined to the
lower surface.

‘The first six segments of the body are almost equal,
the seventh is obsolete. The first pair of legs are pre-
hensile, and the mechanism is rather curious; the fifth
joint is very large and rounded, the inferior angle of its
distal extremity is armed with four large and strong
teeth, two of which are large, the other two being
smaller ; the sixth joint is not so large, and is reniform ;
the seventh joint is long and pointed, bearing at its ex-
tremity a strong claw. The following six pairs of feet
are ambulatory. They are very spiny, and the last joint
is armed with two strong claws, which are not placed in
the usual way, but with the one above the other; the
superior is largest and strongest. The tail is composed
of two segments: the first, which is largest, is of a square
shape, and is armed with two strong spines at its pos-

828 ASELLIDA.

terior angles. The last segment is almost triangular ; the
apex being directed posteriorly, two small styles arise
from each side of the apex.”

[We have copied Mr. Goodsir’s figure of the tail at z,
which shows that there is only one pair of caudal styles,
and not two pairs, as his description would lead us to
infer.] ‘* All the external margins of both of these
segments are thickly fringed with minute hairs and
spines. The branchiz are almost semicircular, and each
of them is armed on its internal edge with a small
appendage. The external plate of the branchiz is
extremely narrow, and is not composed of two equi-
lateral pieces, as in the other Asellide, but consists of
one piece only, with an immovable suture in its mesial
line. It is attached to the body by its base only.”

This species was found by the late Mr. H. Goodsir in
the Frith of Forth. It is quick and active in its move-
ments, running among the branches of coralline with
great rapidity. Mr. Goodsir never observed it swim-
ming, its legs being, indeed, unfitted for that kind of
locomotion; when pursued along the bottom, it runs
quickly, but often stops suddenly, turns round, and
assails its annoyer. We have received it from Mr.
Robertson, who took it at Kames Bay, and from the
Rev. A. M. Norman, who found it at Cullercoats and

Seaham,

MUNNA WHITEANA. 329

ISOPODA,. ASELLIDA,
NORMALIA,

Pe Ly
——

MUNNA WHITEHEANA.

Specific character. Male, with the cephalon nearly half the length of the
pereion, with the eyes very wide apart, fixed on thick peduncles. Upper
antenne with four very short basal joints, followed by a very long slender
one, terminated in a short triarticulate flagellum, and two long auditory cilia.
Pleon about as long as the cephalon, narrower than long, armed with three
strong teeth at each side.

Length, rather more than half a line.

Tue head is very large and broad, increasing in width
posteriorly, equal in length to the three following seg-
ments; the eyes are fixed on very thick and prominent
peduncles. The front of the head is nearly truncated,
and the upper antennz are affixed widely apart next
the anterior-lateral angles of the head. The peduncle
consists of four very small joints, of which the first is
most robust, and a fifth, that is very long and slender,

830 ASELLIDA.

which is terminated by a flagellum composed apparently
of three very minute articulations, at the base of which
arise two delicate, slender filaments or auditory cilia,
about half the length of the preceding joint. The
lower antennze are much longer than the entire animal,
and consist of three small basal joints, followed by two
long and slender ones, occupying nearly half the length
of the whole antennz, followed by a long and slender
multiarticulate flagellum. The first segment of the
body is nearly as large as each of the three following,
whilst the three terminal segments gradually decrease in
width and length, each having the sides produced into
rounded lobes. The tail is elongate-ovate in form, con-
stricted at the base, with three strong teeth on each
side, the last part being affixed in a slight incision on
each side near the tip, and apparently representing the
minute caudal appendages.

The fore legs are short and subchelate, the three follow-
ing long and slender, whilst the three posterior pairs are
still longer, all except the anterior pair being terminated
by two strong curved ungues of unequal size. This
species was first named by us Monimia Whitiana, in
compliment to Mr. Adam White, late of the British
Museum, and described at the meeting of the British
Association for 1852, from a specimen obtained at Wey-
mouth by Professor Williamson; and we have since
received it from Cumbrae, where it was taken by Mr.
David Robertson, of Glasgow, amongst the fibres of
the nest of Lima hians. They were generally much
covered with particles of fibre, and were sluggish in their
movements.

LEPTASPIDIA. ool

ISOPODA. ASELLIDA.
NORMALIA.

Genus—LEPTASPIDIA.

Generic character. Animal pear-shaped, flattened, ciliated
along the margins; inner pair of antenne nearly one-third of
the length of the outer pair; legs terminated by single acute
dactylos ; pleon ovate, extremity entire; uropoda lateral; eyes
obsolete.

We have established this genus for the reception
of a minute animal, which differs in several of its
characters from the rest of the family, but agrees
with them in the dilated form of the body, with
the margins of the segments ciliated, and the semi-
circular form of the head, with the lateral posterior
angles rounded. We have not observed the eyes in our
unique specimen. The upper or inner antennze, which
are most probably represented in our cut too wide apart,
are nearly one-third of the length of the outer pair,
which latter are about half the length of the animal,
and appear to consist of three nearly equal-sized basal
joints, and an articulated flagellum. The segments of
the body are rounded and ciliated, gradually decreasing
in width and length from the second joint. The legs
are extremely short and slender, the anterior having the
wrist and hand somewhat thickened, all terminating in a
single slender and acute finger. The tail resembles that
of the genus Munna, and is oval in shape, flattened and
ciliated with a slight notch on each side beyond the
middle, each impression bearing a small conical appen-
dage (uropoda), the extremity being produced back-

302 ASELLIDA.

wards, rounded and entire, resembling the minute ap-
pendages existing on the telson of some Stomapod
crustacea. The outer pair of branchial plates shut
together in the form of a flattened pear, divided down
the centre: they cover the greater part of the underside
of the tail.

We have but little hesitation in classifying this genus
with those that Professor Sars and his son have described
under the name of Jsopoda Remagantia, and for which
Professor Lilljeborg has established the family of Mun-
nopside, and which are pointed out by Professor Kroyer
as having an affinity with the genus Munna. The typical
form of the three posterior pairs of pereiopoda are
developed into paddle-shaped organs, from which pecu-
liarity the name of the group was given by Sars. But
in the progress of his observations he found that others,
assimilating to the type in most points, had not the
three hinder pairs of legs so developed: hence, in his
description of Macrostyles spinifera, he writes of these
appendages as ‘‘ Korum structura ad natandum parum
apta esse videtur ” (vide Zoological Record, 1864, p. 295).

The family is also described as containing animals
having no eyes; but we know that subterranean crustacea
are generally so, as agreeing with their peculiar habits ;
but even in these, as far as our experience instructs,
the organs are preserved, but reduced to a rudimentary
condition. In the nearly-allied genus Munna, the eyes
are large, and placed at the extremity of a fixed process.
But in the other Asellide the organs are less prominent ;
and in all other respects we see nothing that can induce
us, with the information that we possess, to separate
this genus (and we believe also the Isopoda Remagantia)
from the Asellide.

LEPTASPIDIA BREVIPES. 339

ISOPODA. ASELLID.
NORMALIA.

LEPTASPIDIA BREVIPES.

Specific character. Cephalon large, semicircular, with a slight depression
in the middle of the anterior margin, its posterior lateral angles rounded.
First segment of the pereion with the fore margin emarginate, for the reception
of the hind part of the head; lateral margins of the segments of the body
entire, rounded, and ciliated.

Length, one-twentieth of an inch.

Weare only acquainted with a single individual of the
single species upon which we have established this genus,
the specific characters of which cannot consequently at
present be distinguished from the generic ones, and as our
specimen was sent to us mounted for the microscope, we
have not had sufficient epportunity of observation to
allow us to detail the precise structure of the several
parts. ‘The antennz are implanted on the under surface

384 ASELLID®.

of the cephalon considerably within the margin. The
anterior pair we take to be those that are figured pos-
teriorly in our cut, the basal parts of which are seen
through the transparent tissue. These have the joints
of the peduncle, which we believe to be of the normal
number, surmounted by a slender flagellum consisting of
four articuli. The posterior pair of antennz are much
longer, having the joints of the peduncle very long, and
terminate in a slender flagellum, consisting of one long
and four short articuli.

The anterior pair of legs (first pair of gnathopoda) are
moderately robust, and terminate in a hand of con-
siderable prehensile power. All the other legs are
slender and tolerably free from hairs. The pleon is pear-
shaped, broader anteriorly: on each side, somewhere
about two-thirds from the anterior margin, the posterior
pair of pleopoda are implanted in the margin, these are
fringed with two or three very fine cilia; between this
and the anterior margin the edge of the pleon is fringed
with a delicate, serrated margin: so transparent is the
structure, that it escaped our observation, when we drew
the figure, that nine minute teeth were present. On
each side of the pereion the hairs are connected
togethef by an exquisitely fine fibrous membrane, that
nearly reaches to their extremities.

The animal lives in the mud; two or three specimens
have been taken by Mr. Robertson at Cumbrae, to whom
we are indebted for it.

JANIRA. 335

ISOPODA. ASELLIDA.
NORMAL/4A.

Genus—JANIRA. (Leach.)
ONISCODA. (Latreiile.)

Generie character. Pereion serrated along the lateral margins;
pleon having all the segments coalesced into a single plate;
covered, in the female, beneath with a large, flat membranous
plate concealing the branchial feet ; and furnished at the tip with
a pair of elongated bifid uropoda. Outer antennz as long as
the animal. Dactyla biunguiculate.

Tuts genus has hitherto been known only by Leach’s
short and insufficient characters, which have been repro-
duced by subsequent authors ; it is closely allied to Jera in
its general character, but is at once distinguished by the
pair of elongated styles at the extremity of the tail,
each of which is terminated by a pair of narrow, slender
plates, as in the genus Asellus.

These styles are liable to be detached at a very slight
touch, and hence many specimens of the animal are
found destitute of them. They arise in a terminal
emargination of the segment, but smaller than in
Jera, and having its postero-lateral margin finely ser-
rated. In the males, the large terminal segment is
furnished at its base, on the underside, with the male
organ, which is narrow, flattened, nearly reaching to the
extremity of the segment, and with its tip quadriden-
tate. In the female, this terminal segment is entirely
covered with a very thin membranous operculum, con-
cealing the branchial apparatus. The outer antenne,

336 ASELLID A.

in fully developed individuals, are longer than the whole
animal. The flagellum is very long, and composed of
a vast number of articuli, which are twice as broad as
long, each of which appears to consist of three still more
minute divisions; the inner antennz have on the second
joint of the peduncle a small pointed articulate scale, the
homotype on the large squamiform plate attached to the
third joint of the peduncle of the inferior antennz in the
macrourous Decapoda; they are terminated by a slender
multiarticulate flagellum, reaching beyond the middle of
the long third joint of the outer pair. The fore legs (first
pair of gnathopoda) are somewhat more robust than the
following limbs, and in this pair the terminal ungues are
unequal in size. The parts of the mouth resemble those
of Jera, except that in the mandibles we failed to detect
the palpiform appendage, which may have been broken
off. The labrum is rounded in front, with a deep
central incision (fig. *).

We have restored Dr. Leach’s name of Janira to this
genus, which Latreille, with complete disregard to the
rules of priority in nomenclature, had changed to Oniscoda.
The former name was published in the ‘‘ Edinburgh
Encyclopzedia,” vol. vii., previous to 1814, as Dr. Leach
himself, in his “ Memoir on the Classification of the
Linnzan Insecta,” read at the Linnean Society in the
early part of 1814, refers to his article in the “ Edinburgh
Encyclopedia.” In 1826 Risso, finding that the name
Calypso, which in 1816 he had given to a genus allied to
Galathea, had already been used by naturalists, proposed
that of Janira in its stead, in the Errata to his
“* Natural History of the Crustacea of Nice; ” Latreille,
however, overlooking the prior employment of the name
Janira by Leach, rejected that name and proposed that
of Oniscoda in its stead, in the ‘‘ Familles Naturelles du

ONISCODA. 337

Réene Animal,” 1825,* forgetting that he had himself
used that latter name for the tribe, of which Oniscoda
is the type.

* The effect of forgetting that he had himself used the latter name for
the tribe of which Oniscus is the type, and this restoration of the name
Janira to Leach’s genus will be, that Risso’s decapod genus, successively
named Calypso and Janira, will require a third generic name.

NEAR FOLKESTONE,

VOL. Il. Z

338 ASELLID®.

ISOPODA, ASELLIDA.
NORMALIA.

JANIRA MACULOSA,.

Specific character. Ash-coloured, entirely covered with minute dark-
brown dots; segments of the pereion finely but irregularly denticulated along
the lateral margins. Pleon serrated on the latero-posterior margin. Basal
joint of the uropoda as long as the terminal rami, of which the outer one is
slightly longer than the inner,

Length, from one-quarter to one-third of an inch.

Janira maculosa. Lrscu, Edin. Enc. vii. p. 434. Trans. Linn. Soe. xi.
p. 373. Suppl. Enc. Brit. i. p. 428. SamovE.iy,
Ent. Compend, p. 110. Wutrs, B. M. Cat. Brit.
Crust. p. 70. Raruxe, Nov. Acta. xx. p. 24.

Oniscoda maculosa, Latrerin, Régne An. iv. p. 141. Mitne Epwarps,
Crust. iii. p. 151. Wire, Pop. Hist. Brit. Crust.
p. 184, pl. 12, f. 7. Gossz, Man. Mar. Zool. 1,
f. 244,

Tue body is flat and oblong, rather than ovate, in form,
in consequence of the width of the head and tail. The

JANIRA MACULOSA. 339

segments of the body are transversely channelled near the
anterior margin of each, and each segment has its lateral
margin marked with small incisions (that vary in speci-
mens), giving a serrated appearance to the animal. The
white upper surface is punctured and marked with
minute dark-brown dots. The eyes are placed some-
what on the disc of the head, instead of occupying its
posterior lateral angles. The two basal joints of the
peduncle of the posterior pair of antennz are short
and stout; the third is also short, but much narrower ;
the fourth and fifth are long and slender, and the whole
terminate in a long multiarticulate flagellum. On the
second joint of the peduncle is a short, pointed, arti-
culated plate; this is tipped with three hairs.

The first pair of legs are somewhat larger in the male
than in the female, and have the carpus short and
superiorly produced over the propodos; the propodos
is long, narrowly oval, and armed along the inferior
margin with two or three short robust spines; the
dactylos is as long as the propodos, fringed with minute
cilia along the concave margin, which impinges closely
in its entire length against the inferior margin of the
propodos, and has its extremity furnished with two
curved ungues.

The tail consists of a single plate; it is flattened and
nearly circular, with the latero-posterior margins finely
serrated, the extremity having but a small incision, the
terminal styles (which are about equal to the entire tail
in length, with the basal joint about as long as the two
terminal branches) being affixed beneath the margin of
the tail, so that their place of insertion is not seen
from above.*

* We believe that the length of the antenne, and the amount of serration
at the sides of the body and tail, vary according to age and sex.

Zw

340 ASELLID&.

Colonel Montagu’s typical specimens in the British
Museum have served for our figures of this species.
They were taken on the coast of Devonshire; Mr. N. P.
Cocks found it in crevices of rocks at Falmouth. We
also have it from Polperro, captured by Mr. Couch,
from Berwick Bay, taken by the late Dr. G. Johnston ;
the Rev. W. Norman also obtained it on the Durham

coast.

ASELLUS. 341

ISOPODA. ASELLIDZ,
NORMALLA.

Genus—ASELLUS. (Geoffray.)

Generic character. Flagella of all the antenne multiarti-
culate, lower pair more than half the length of the body; eyes
round and lateral; pereiopoda uniunguiculate ; pleon with two
long and exserted bifid appendages.

THE species of this genus have the body oblong, rather
narrowed towards the head, with eight rather deep lateral
incisions between the various segments of the body,
which are depressed and slightly irregular on the upper
surface, the sides being furnished with strong, irregular
lengthened spines. The head is transverse, scarcely nar-
rower than the body, the fore margin nearly straight, the
eyes small, round, and quite lateral. The upper antenne
about twice the length of the head, and very slender;
the lower antennz more than half the length of the
animal, cylindrical, all the antenne having a multiarti-
culate flagellum, which is very long in the lower pair.
The segments of the body are nearly of equal size, each
being marked with an impressed transverse line near the
base. The fore pair of legs are rather short, robust
(especially in the males), and terminated by a subcheli-
ferous hand, with apical hook-like finger; the three fol-
lowing pairs of legs are longer, much more slender, and
simply ambulatory ; and the three hind pairs of legs are
gradually longer, all being terminated by a simple acute
and curved finger. The tail consists of a large shield-
like joint, with indications of two very short joints at

842 ASELLIDA.

its base, and with its extremity forming two wide but
shallow emarginations, within which are affixed two long
caudal appendages (or uropoda), composed of an oblong
basal joint, supporting two elongated branches. On its
under surface the tail bears two opercular plates, divided
transversely by an articulation across the middle, which
cover the branchial plates, and bear at the base a com-
plex apparatus in both sexes.

The only British species, and two others, natives of
North America, occur in fresh-water ponds and lakes.

The following vignette, taken for us by the Rev. J. M.
Joass, of Eddestown, is a view of the Blasted Heath of
Shakespeare, Forres seen in the distance, taken near a
pool from which the Rev. George Gordon has sent us
some very large specimens of Asellus aquaticus.

THE BLASTED HEATH, FORRES.

ASELLUS AQUATICUS. 343

ISOPODA. ASELLIDA.
NORMALIA.

ASELLUS AQUATICUS.

Specific character. Upper antenne reaching to the extremity of the
peduncle of the lower; flagellum of the lower twice the length of the
peduncle, Pereion of a greyish colour, mottled with paler markings; pedun-
cle of the caudal appendages nearly half the length of the slender terminal
subequal filaments.

Length of the male, nearly half an inch; female, much smaller.

Oniscus aquaticus. Linn. Syst. Nat. ii. p. 1061. Roxumer, Gen. Ins.
pl. 30, fig. 12.

Cymothoa aquatica. Fapricius, Ent. Syst. i. p. 505; Ejusd. Suppl.
p. 303 (Idotea aq.).

DP Aselle. Grorrroy, Ins. Paris, ii. p. 672, t. 22, f. 2.

Asellus aquaticus. OuivieR, Enc. Méth. iv. p. 252. Lxeacu, Trans.

Linn. Soc. xi. p. 373. GusRIN MENEVILLE,
Icon. R. An. Crust. t. 31, f. 3. SamovE te,
Ent. Compend. p. 110. Wuuirr, B. M. Cat.
Brit. Crust. p. 69; Pop. Hist. Brit. Crust.
p. 230, pl. 12, f. 6.

344 ASELLIDA.

Squilla asellus. De Geer, Ins, vii. t. 31, f. 1—20.

Asellus vulgaris. LATREILLE, Hist. Nat. Crust. et Ins. vii. p. 359,
t. 58, f. 1. Dssmarzst, Cons. Crust. p. 314,
t. 49, f. 1, 2. Minne Epwarps, Crust. iii.
p. 146. Cuviur, R. An. (edit. Crochard) t. 70
(Hy as ale

Entomon hieroglyphicum. Kuiy, Remarq. s. 1. Crust. fig. 5.

Turis is a very common auimal, occurring in fresh-water
ponds and ditches throughout the kingdom. The male
is much larger than the female. The head is about half
the size of the following segment ; its underside is nearly
covered by the large outer pair of foot-jaws, which con-
sist of an oblong flattened basal joint (furnished on the
outside, at the base, with a large semi-oval plate, Régne
An. Ed. Crochard Crust., pl. 70 dis, fig. 1 a, and Treviranus
Verm. Schr. t. xi. fig. 59 a, a), and five short terminal
joints, of which the first is produced into a lobe at its
inner extremity, and the last forms an acute finger-like
joint. _ The mandibles (Treviranus o. c. fig. 63) are
armed on the inside with a strong, horny tooth, and on
the outside with a three-jointed palpiform appendage.
The inner maxillz are described by the same author
(fig. 60) as only having two terminal setose lobes, and
the outer (fig. 61) as formed of two lobes, the inner
one much more slender than the outer. The bilobed
labium (fig. 62 z) lying between the base of the man-
dibles, is described by Treviranus as the third pair of
maxille.

The ventral surface of the segments of the body, in
the males, is marked with strong transverse corrugations ;
in the female, it bears the large ovigerous sac, within
which the young are developed. The male, as is well
shown by Treviranus o. c. fig. 65 p. and 66 z, is fur-
nished with a pair of small and narrow curved horny
lobes in the middle of the hinder segment of the body,

ASELLUS AQUATICUS. 345

on its underside, followed by a pair of small crustaceous
sac-like appendages, constricted (ib. fig. 67 p. and De
Geer, vil. pl. 31, fig. 12 e, e), which partially conceal a bi-
partite, complex, horny apparatus, each portion consisting
of a large basal joint (partly visible in the upper part of
our figure, P), which supports two small knob-like ap-
pendages, the innermost of which is armed with a small
horny spur, directed backwards (De Geer, fig. 18 x, and
Treviranus, fig. 67). This apparatus was first very carefully
described and figured in detail by De Geer, and sub-
sequently more satisfactorily by Treviranus. In the
female, this apparatus is replaced by two small semi-oval
plates, strongly ciliated along the terminal outer edge,
which rest upon the base of the outer pair of branchial
plates, the latter being divided into two nearly equal
portions, as in the male.

The following excellent account of the habits of this
animal is given by Sir J. Dalyell, in his fine work on the
*“* Powers of the Creator” :—

“The species abounds in remarkable profusion in a
pond at Red Braes, in the immediate vicinity of Edin-
burgh. None exceed six lines in length, and little more
than half a line in breadth. It feeds upon vegetable
matter exclusively. The leaves of the beech in decay
are preferred, and in such parts of the pond as these are
most abundant, there the Asel/lus is most numerous.
The animal does not generally swim, it runs freely and
expeditiously over the decaying leaves.

‘* The breeding season extends through several months
of the year. The ovarian pouch occupies the under
surface of the thorax and abdomen, and contains about
forty ova. Many of the young, very minute and almost
white, recently hatched, were running about over and
under the leaves on the 22nd May. The young animal

346 ASELLID®.

is about half a line long, and transparent under the
microscope.

‘«¢ The young in one instance were observed to be hatched
during the week previous to the 22nd July, but in one
year each of these specimens had a cluster of white ova
on the thorax in the middle of September.

‘* The posterior extremity of the young is proportion-
ably more obtuse than in the parent. Further, unless it
be immediately or speedily consequent on production from
the ova, they do not seem to undergo any conspicuous
metamorphosis.

** Exuviation is less frequent here than in many other
crustaceans. The integument, however, separates in
two portions, which are nearly white.

“‘ This is an extremely pacific, tranquil creature, always
seeking shelter. Specimens have survived many months
when kept in confinement.”

The development of the eggs and young of this species
has been carefully investigated by De Geer, in his great
work on Insects, and more recently, in greater detail, by
Rathke,* from whose elaborate series of illustrations the
accompanying figures have been selected.

The eggs having been discharged from the oviduct,
are entirely destitute of any trace of germ, and are
retained and hidden beneath the four pairs of large,
slender, and semi-transparent scales attached to the under
surface of the body of the female, where the young are
disclosed, and remain until they have assumed a form
similar to that of their parents. Our first figure repre-
sents the egg in its early state, filled with the yolk and
enclosed in a thin chorion.

* Abhandlungen zur bildungs und entwickelungs Geschichte des menschen
und der Thiere. Liepzig, 1832, 4to, Erster Theil, p. 3 tab. 1. Translated in
Annales Sci. Nat., 2 sér. Zool. tom. 2.

ASELLUS AQUATICUS. 347

EMBRYONIC DEVELOPMENT OF ASELLUS AQUATICUS.

In figure 2, the egg is further advanced, showing
the molecules of the head, and one of the external
lateral appendages. In figure 3, the embryo is seen
in front, showing the rudiments of the two pairs of
antenna, labrum, five pairs of mouth-organs, and
the two lateral external appendages. Figure 4 shows
the embryo a little more advanced, and figures 5 and
6 the same, with the body stretched out and seen
dorsally and laterally, exhibiting the eyes, segments
of the body and tail, the latter figure representing the
antenne thrown backwards laterally, and the rudimental
legs. At this period the enclosed animal does not ex-
hibit the slightest voluntary or involuntary movements,
and Rathke consequently regards the Asellus as emerg-
ing from the egg in a more imperfect state than any

~

other articulated or vertebrated animal. At figures 7

348 ASELLIDA.

and 8, the embryo is now nearly arrived at its full
development, the legs exhibiting traces of articulation,
and the lateral appendages having lost their trilobed ap-
pearance; the mandibles, two pairs of maxillz, foot-
jaws, and branchial plates, and the terminal appendages
of the tail are visible in figure 8; lastly, in figure 9,
the embryo is seen in its final stage, with the large
lateral antenne articulated, and the lateral appendages
entirely lost. In figures 6 and 9 it will be observed
that there are only six leg-bearing segments, and six rudi-
mental pairs of legs, whilst there are seven segments and
as many pairs of legs in the fully developed animal;
Rathke affirming that “le dernier de ces anneaux et
sa paire de pattes ne se forment qu’en peu de tems aprés
la sortie du jeune de la cavité incubatoire” of the
mother; he, however, asserts that the wanting seventh
segment is produced by the division into two parts of
the sixth segment before the first moulting of the ani-
mal, but admits that the formation of this last pair of
legs ‘‘m’est restée assez obscure,” partly because it is
effected very rapidly, and partly because the other legs,
being long, cover all the hind parts of the body.*

We have ourselves examined the earliest stages of
these animals, and our observations agree with those of
Rathke, except that in the early embryonic condition
the lateral appendages appeared to us to be entire, with
a rounded terminal knob, instead of being tripartite, and
that in the state corresponding with that of our lower
right-hand figure, the upper pair of antennz are free,
as in figure 9, and that the external sac-like appendages
were associated with the hepatic lobes.

* This circumstance is of considerable importance, viewed in connection with
the question of the number of legs in the early stages of Entoniscus and
Cryptothiria (Liriope).

LIMNORIA. 349

ISOPODA. ASELLIDA,
NORMALLIA.

Genus—LIMNORIA. = (Leach.)

Generic character. Oblong-ovate, depressed ; antenne sub-
equal, cylindrical, not longer than the cephalon. Pereiopoda
nearly alike, slender. Pleon six-jointed. Branchial plates naked.
Terminal segment large, semicircular, with a lateral appendage
on each side bearing two terminal slender styles.

Tue small animal which forms the type of this
genus is oblong, rounded in front and behind, and sub-
depressed. The head is short and round, with the eyes
wide apart, composed of but few facets. The antennz
are of nearly equal length, being scarcely longer than
the head, and terminated by a bristly pencil of hairs, the
upper pair composed of three small joints and a small ex-
articulate flagellum, and the lower pair also composed of
three joints, with asmall articulated flagellum. The outer
foot-jaws consist of a long basal joint, closely united to
the following, the inner apical angle of which is con-
siderably dilated, produced and setose ; the four following
joints are also short, with their inner angles similarly pro-
duced. At the base is attached an elongated triangular
plate; this plate is developed to its fullest extent in the
Idoteide. The mandibles are elongated, flattened, horny,
broadly truncated at the extremity, and furnished with
a triarticulate palpiform appendage. The first pair of
maxillz consist of two very delicate elongated plates, the
inner one being the more slender and curved; both are
setose at the tip, but the inner has, moreover, a strong
curved spine at its inner extremity. The second pair of

350 ASELLIDA.

maxillee are also very delicate, furnished with three
oblong-ovate terminal plates, setose at their extremities.
The legs are short and slender, all being formed neatly
alike, the four anterior ones being, however, rather more
robust and tuberculated on the basal joints, all terminat-
ing with a small slender curved finger. The tail consists
of six segments, of which the four basal ones are short
and equal, with the posterior margin entire; the fifth has
the posterior margin irregular, and the sixth is large,
semicircular, flattened, with a slight central ridge; on each
side it bears a lateral appendage, of which the basal
portion is nearly square, with the outer margin notched,
and terminating in a strong, curved, movable spine; the
apical portion forms a slender style, with strong bristles at
its extremity, which appears to be separated into a minute
articulation. The ovigerous pouch of the female consists
of four pairs of scales, affixed to the middle segments
of the body, and the tail is furnished on its underside
with six pairs of scale-like, branchial plates, forming three
rows, which are naked and of equal size. These plates
are received, as in the Spheromide, in a cavity formed by
the excavation of the underside of the caudal segments.
In this respect, and especially in the segmentation of the
pleon, the genus is removed from the remainder of the
Asellide ; indeed, Dr. Leach formed it into a distinct race
in his great family Cymothoade, which also included the
Serolide, Higide, and Spheromide.

The whole of the dorsal surface is covered with stiff,
pinnated hairs, amongst which numerous minute para-
sites, somewhat like Hcehinorhynchit and Acari, are con-
stantly to be seen. They even infest the branchiez.

LIMNORIA LIGNORUM. 351

ISOPODA. ASELLID.
NORMALIA.

LIMNORIA LIGNORUM (THE GRIBBLE).

Specific character. Entirely covered with small, setose hairs. Lower an-
tennze not longer than the head. Terminal segment of the tail entire,
rounded, and flattened, with a slight central dorsal carina, and the lateral
margins raised,

Length, about a line and a half.

Cymothoa lignorum. RaruKe, Skrivt af Naturh. Selsk, vol. 101, t. 3, f. 14
(1799).

Limnoria lignorum. Wutrn, Pop. Hist. Brit. Crust. p. 227, pl. 12, f. 5.

Limnoria terebrans. Luacu, Dict. d. Sci. Nat. art. Cymothoadées, Edinb.
Enc. vii: p. 4383. ‘Trans. Linn. Soc. xi. p. 371.
Suppl. Enc. Brit. 1, 428. Drsmarzst, Cons. Crust.
p. 312. Samovenie, Ent. Compend. p. 109. Coup-
STREAM, in Edinb. New Phil. Journ. xvi.* p. 316,
t, 6, f. 1—16. Horx, Trans. Ent. Soc. Lond. 1,
p. 119. W. Tuompson, Edinb. New Phil. Journ.
xviii. p. 127. Mitne Epwarps, Crust. iii. p. 145.
Waitt, B. M. Cat. Brit. Crust. p. 68. Gosss,
Man. Mar. Zool. 1, fig. 242. Wurstwoop, in Qar-
dener’s Chronicle, 1849, p. 388, fig. annexed.

* This and the preceding plate are erroneously lettered ‘‘ vol. xvii.”

352 ASELLIDA.

TuE GRIBBLE is one of the most destructive creatures
to be found amongst the whole of the articulated animals,
burrowing into the wood of marine erections, such as
piers, piles, and other works of public utility. Being the
only known species contained in the genus, its leading
characters have been detailed above, and in the generic
description. The male is about one-third larger than
the female. In general, not more than seven, or at most
nine, young ones are found within the incubatory pouch.
When the animal is alive, it contracts itself almost into a
ball, thus confirming the relationship of the genus to the
Spheromide. They are able to live at least a fortnight
within the wood, taken out of the water and placed in a
dry room. Each of the eyes is composed of seven or
eight blackish facets, one being in the centre. ‘The legs
are articulated just beneath the sloping lateral margins of
the body, and being partly folded beneath the pereion, a
small portion only of each is seen when the animal is in
motion. The longest are the first and fifth pairs; the legs
of the second segment are shorter and thicker than those
of the first, the third and fourth pairs being similar to
the second; the fifth pair is more slender, and the sixth
and seventh pairs resemble the fifth, but are rather
smaller. The terminal finger is, in all the legs, single and
somewhat hooked.

Dr. Coldstream describes a peculiar organ situated
within the cavity of the tail, behind the branchia, con-
sisting of two vesicular bodies of an oval form, attached
toa common peduncle. They were always found filled
with numerous dark-coloured granules, of an irregularly
round shape, which could not be detached from the sub-
stance in which they were embedded by tearing it up.
They exist in both males and females. The animal creeps
but very slowly, backwards as well as forwards, appearing

LIMNORIA LIGNORUM. 353

to drag itself along. It turns rapidly, using chiefly the
caudal plates, which it uses as oars; sometimes also it
propels itself by a sudden movement of the tail, back-
wards, to the distance of an inch or more, through the
water.

It appears that, notwithstanding the extent and im-
portance of its ravages upon structures, affecting the
interests of mankind in a very extensive manner, it was
not noticed until about the year 1811, when Dr. Leach
announced it, as a new and highly interesting species,
sent to him by Robert Stevenson, Esq., the celebrated
engineer, and as occurring in the greatest abundance at
the Bell Rock lighthouse on the Scotch coast, erected
by that gentleman, burrowing into the old woodwork,
which it perforated in a most alarming manner, entering
into it to the depth of several inches by boring in every
direction, generally in straight lines, avoiding, however,
the knots of the timber, round which it works.

Many kinds of wood, including old oak, are devoured
by the Limnoria, although it was generally found in other
timbers, especially Memel fir. Mr. Stevenson saw it
attack oak, black-birch, and other woods; indeed, teak
was the only wood exposed to its ravages which was not
perforated. Its mode of attack is very similar to that of
the common Anobium in the timber of houses, &c., which
is so often mistaken for dry rot, the chief difference
being that the action of the waves wash away the outer
and harder annual layers, in consequence of all the soft
intervening spaces being eaten away, whilst the inner
ones, as well as the knots of the branches, stand out
in relief—consequently the surface of the wood soon
becomes gradually rotten and reduced in its dimensions,

It is by means of its mandibles that it forms its
burrows in the wood, which evidently forms its support,

VOL. II. AA

354 ASELLIDZ.

as the stomach is found filled with minute ligneous par-
ticles. The burrows are about one-fifteenth of an inch
in diameter; they are cylindrical, and perfectly smooth
on the inside.

We must refer the reader to Dr. Coldstream’s valuable
memoir (from which most of the preceding details of the
habits of the species have been derived) for an account
of the injuries committed by these little depredators in
various parts of the Scottish coast; as well as to Mr.
Thompson’s memoir, in the 18th Volume of the ‘* Edin
burgh New Philosophical Journal,” where numerous
Irish localities are recorded, and to Mr. Albany Han-
cock’s memoir in the “ Newcastle Naturalists’ Trans-
actions.” Mr. Hope’s suggestions in the “ Transactions
of the Entomological Society,” vol. i. p. 119 and xxxiv.,
must also be referred to for their practical character.
It was observed by Mr. Spence, at Bridlington Bay,
near Hull, and Dr. Moore stated in ‘* Charlesworth’s
Magazine of Natural History,” that its injurious effects
had been observed for forty years in Plymouth Harbour.

Through the kindness of the superintendent, Admiral
Drummond, we have recently had the opportunity of
examining into the extent of the depredations of this
little creature on the submerged timber in the Royal
Dockyard at Devonport.

It is the opinion of Mr. Moore, the able and intelligent
master shipwright, who has had the opportunity of ob-
servation extending over thirty years, that the ravages of
the gribble in this dockyard is considerably less than it
was at the early part of his career.

But this appeared to us to be more the result of suc-
cessful attempts in the great care and ability shown in
protecting the timber from the action of the animal, than
in the decrease of this creature in the locality.

LIMNORIA LIGNORUM. 395

The means taken to protect the woodwork are of
several descriptions, viz., copper sheathing; iron nails
closely studded; (the ferruginous oxide that the action
of sea-water produces, impregnates the wood, and forms
a protective iron crust all over the surface ;) creosote
and coal-tar are likewise used, and it is the opinion of
Mr. Moore that all timber that can be smeared over once
a year, is effectually freed from the ravages of the
Limnoria.

The action of these animals is more or less rapid,
according to circumstances. Pinewood they appear to
destroy about the rate of one-quarter to half an inch
in a year: of course this must be less rapid during
the first year or so, and more rapid after several years,
for the numerical increase of animal life must be
greater in proportion to time. We find that that portion
of the pine framework that supports the hull of the
Robust frigate, that was commenced being built on the
3lst of October, 1859, and is submerged at every tide,
has been eaten in many places from two to three inches,
while an inspection of the pine scaffolding round the
half-built fort just within the Plymouth breakwater and
harbour, erected between three and four years, shows us
that the extent of the depredation amounts to from
three-fourths of an inch to an inch and a half, according
to the nature of the wood and its freedom from any pro-
tecting influence. The little animals invariably choose
the softer places, shunning the knots and hard lines of
wood that longitudinally connect one knot with another.
They likewise avoid every part of the wood that had
been impregnated with iron, sometimes for several inches
round the place where a nail or bolt had been driven.

Oak they attack not so readily as pine, but still the
former gradually falls before their persevering action, the

AA 2

356 ASELLID®.

softer or more sappy portion disappearing more rapidly
than the more solid parts. Thus it would appear that it
is necessary that all timber must be somewhat softened
by the water before they commence their depredations.
We have been indebted to Mr. H. Pownall for speci-
mens of the injured timber, and individuals from the
Southampton Water, extending to woodworks a mile up
the Itchen river. It appears to be very general all
round our coast. It is abundant in the river Dee, and
the piles supporting the rock lighthouses at New Brighton
are drilled by them. The late Mr, W. P. Cocks found
them also in wood cast on shore at Falmouth, and the
Rey. A. M. Norman has sent it us from the Shetlands.

ISOPODA LIBERATICA, II. 357

ISOPODA LIBERATICA.—Sub-tribe II.

THE animals comprising the second sub-tribe of the
Isopoda Liberatica (which is equivalent with the family
Idoteides of M. Milne Edwards) differ from the general
form of the order in the greater elongation and paral-
lelism of the body, which is more or less abruptly trun-
cated at each extremity. In the most extreme forms
the body is quite cylindrical, resembling that of the
larvee of certain Lepidopterous insects (Geometra), even
in its peculiar movements and position when at rest.
The eyes are large and lateral, the anterior pair of an-
tenn are very short, and inserted above the posterior
pair, which are considerably—occasionally very much—
elongated. The mandibles are short, robust, and horny,
with a strong denticulated apical incurved tooth, below
which, on the inner margin, is a smaller denticulated and
movable tooth: these organs are destitute of a palpiform
appendage. The outer foot-jaws have the second joint
produced into an elongated plate, ciliated at the tip with
a hook in the middle of its interior margin; the four
terminal joints are variable in size, the fourth in Jdotea
being large and oval, whilst it is very small in Arcturus.
The legs vary both in size and arrangement, the four
anterior pairs in Arcturus being very slender, ciliated, and
directed forwards, whilst the three posterior pairs are
short and very robust, and directed backwards ; whilst in
Idotea the legs are nearly of equal size and character, the
three anterior pairs being directed forwards, and the four

358 ISOPODA LIBERATICA, II.

posterior pairs backwards. In none of the groups are
the fore legs terminated by a didactyle claw. The prin-
cipal character of the tribe consists, however, in the
structure of the tail and its appendages. This part of
the body consists of one large caudal shield, destitute of
lateral appendages, of which one or more of the anterior
segments exhibit evidences of being more or less im-
perfectly soldered together, whilst the branchial plates
are arranged in five pairs, entirely closed over by the
outer, that is, the first or anterior pair of pleopoda, which
shut together like the two divisions of a cupboard door,
and which plates have a transverse division near the ex-
tremity.

The British genera included in this tribe constitute
two families, Arcturide and Idoteide, well distinguished
by the structure of their legs, which has induced Mr.
Dana to remove Arcturus from this division of the order,
and arrange it among his Anisopoda, a mode of distribu-
tion which appears to us unnatural.

Mr. Dana has, moreover, established an additional
family in the sub-tribe, under the name of Chetilide, for
the reception of a Patagonian species, Chetilia ovata,
nine lines long, remarkable for having the sixth pair of
legs twice as long as the entire animal, terminating in a
very long bristle-like extremity, which consists of numer-
ous joints: the seventh pair has also a multiarticulate
extremity, which is, however, quite short.

ARCTURIDA. 359

Family—ARCTURID At.

Tus family, corresponding with the tribe Jdoteides
Arpenteuses of M. Milne Edwards, is composed of the
single genus Arcturus, of Latreille, remarkable amongst
the Isopoda for its slender, cylindrical form, the length
of its lower pair of antennz, and the delicate ciliated
structure of the four anterior pairs of legs; whilst the
hind ones are short and very robust. In the British
species, the fourth segment of the body is greatly elon-
gated, and as the animals affix themselves by means of
their hind pairs of legs, elevating the front part of the
body, and twisting it about in various directions, they
exhibit considerable resemblance to the Caprelle, as also
to the loopers, or Geometrical Caterpillars of the Geo-
metre, whilst the elongated antennez give them also a
strong resemblance to the Amphipodans, constituting the
genus Corophium (vol.i p. 498) ; in fact it is by the assist-
ance of the great antenne that these creatures chiefly
progress, their fore legs being too delicate to serve as
instruments of locomotion.

The species of the group found in the Arctic seas
are of very large size, sometimes reaching three inches
in the length of their bodies. ‘This is the case with the
type of the genus Jdotea Baffini, Sabine, first described
in the appendix to Captain Parry’s fourth voyage. This
species has the fourth joint of the body not much longer
than the adjoining segments, and if it should be con-
sidered necessary to separate the British species, as form-

3860 ARCTURIDA.

ing a distinct genus or subgenus, it will be necessary to
employ for them another name, in which case that of
Leacia, proposed in 1825 in honour of Dr. Leach, by
Dr. G. Johnston, must be used instead of Arcturus, a
step, however, which we by no means considered neces-
sary and advisable.

Mr. Goodsir, who carefully studied the animals of
this group, was not acquainted with the characteristics
of the male sex in the Arcturt, almost all the speci-
mens which he procured having eggs in the marsu-
pium, The eggs are pear-shaped and curved, and have
a tough external membrane, with a granular white and
a light yellow mass towards their centre, which may be
of the nature of yelk globules. ‘The ovaries are two
elongated white granular bodies on each side and beneath
the liver: they open at the third segment of the body, at
the extremity of the marsupium.

ARCTURUS. d61

ISOPODA. ARCTURIDA.
NORMALIA.

Genus—ARCTURUS. (Latreille.)

Leacia. Jounston, Edinb. Phil. Journ. xiii. 219 (1825). Warsrwoop
(subg.).

Astacilla, Fuirmrna.

Leachia. Mitne Epwarps (subg.). H. Goopsir,

Tue chief characters of this genus have been already
detailed in our observations on the family, whilst those
of the British species, as forming a distinct subgenus
from the Arctic type, A. Baffint, are characterized by the
great elongation of the fourth segment of the body
(which we believe varies somewhat in degree according
to the sexes), and which, joined to the more slender
form of the animals, allow a much greater freedom of
movement to the front part of their bodies, enabling them
to hunt for their prey round a fixed spot without moving
from it. The eyes are large, semi-globose, and lateral,
with the anterior-lateral angles of the head produced
in a forward direction. The upper pair of antennee are
very short, and terminate in an obtuse-pointed, uni-jointed
flagellum, whilst the lower pair are very long, sometimes
longer than the entire body, and terminated, in the
typical species, by a multiarticulated flagellum; but in
the British species the flagellum consists of only three
joints, closely united together, deflexed and incurved, the
terminal joint at the tip being formed so as to make a
strong point by which, when fixed in an advanced posi-
tic, the animal is able to pull itself forward.

The anterior pair of legs, although partaking of the

362 ARCTURIDA.

character of the three following pairs, are considerably
shorter and broader, and being more closely applied to
the mouth, they appear to represent a second pair of
maxillipeds, so that the animals may almost be regarded
as exhibiting the anomalous condition of having two
pairs of foot jaws and six pairs of legs, instead of one
pair of the former and seven of the latter, as in the
ordinary Edriophthaima, or three pairs of the former and
five of the latter, as in the Decapoda.

It is in such anomalous groups as these that we see
the advantage, in a scientific point of view, of the identi-
fication of each part by a name that is homologically
true, instead of varying the term with the variation of
form or use that the necessities of animals require. If
we adopted the latter plan, as is too frequently the case
even among some of the best carcinologists, we should be
obliged to name the four anterior pairs of legs in this
genus as four pairs of maxillipeds, and which, added to
the pair which is homologically consistent, would make
five pairs, which would be a manifest absurdity.

The genus was established by Latreille in the second
edition of the ‘“ Régne Animal,” published in 1829
(having been indicated by name only in the “ Familles
Naturelles,’’ published in 1825), for the reception of
Idotea Baffin.* In 1834, Professor Westwood communi-
cated a memoir, with figures, on the genus, which he
regarded as osculant between the normal Jsopoda and the
Lemodipoda of Latreille, to the Entomological Society
of London. (Transactions, vol. i. p. 69.) He divided
the genus into two sections (subsequently adopted by M.

* Latreille gave the species under the undescribed name of A. tuberculatus,
not recognizing its identity with J. Bafini. Even now it is only by conjecture,
or by the synonyms given by M. Milne Edwards, that we are able to identify
the animal intended by Latreille.

ARCTURUS. 363

Milne Edwards): 1. Arcturus Proper, containing Jdotea
Bafimi, and 2. Leacia, Johnston, containing Oniscus
longicornis, Sowerby (to which Dr. Johnston, regarding
it as undescribed both generically and specifically, had
given the name of Leacia lacertosa). Mr. H. Goodsir,
however, considered the two sections as of generic rank,
and accordingly retained the name JLeachia for the
British species. Until recently, a single British species
has only been recognized. The late lamented Harry
D. S. Goodsir, Surg., R.N., however, detected two
other species, of which he published descriptions and
figures in the 3lst volume of the “ Edinburgh New
Philosophical Journal.” Living specimens of all these
three species were captured by Mr. Goodsir with the
dredge in deep water in the Frith of Forth, and in the
German Ocean, but all these were found to be rare in
consequence of their pelagic habitat. Having kept these
animals in glass jars of sea-water, with sand and coral-
lines, Mr. Goodsir was enabled to watch their habits
closely. Under these circumstances each individual will
select a branch of coralline, keeping that branch ex-
clusively to itself, and defending it with the greatest
vigour against all intruders. It fixes itself to its resting-
place by means of its true feet, which it seldom uses for
progression, When it falls to the bottom of the vessel,
it fixes its long-pointed antenne into the sand, and with
the assistance of the true feet drags and pushes itself
forward. This, however, may not be a natural mode of
progression, but may be adopted in consequence of the
artificial circumstances in which the animal is placed.
The ordinary and natural mode of progression of these
animals is swimming. It is amusing to see one of these
animals resting in an erect posture, on a branch of coral-
line, by means of its true feet, waving its body back-

364 ARCTURIDA.

wards and forwards, throwing about its long, inferior
antenne, and ever and anon drawing them through its
anterior fringed feet, for the purpose of cleaning them.
It frequently darts from its branch with the rapidity of
lightning, to seize with its long antennz some minute
crustaceous animal, and returns to its resting-place to
devour its prey at pleasure. In this manner the antennz
are the only organs employed in seizing and enclosing
the prey, which they drag to the anterior feet, which hold
it while it is being devoured. ‘The strong claws with
which the inferior antennz are armed, seem also to be
useful to the animal in the act of prehension, and in an
Antarctic species we find this power increased by the
presence of strong teeth.

The formation of the fourth segment of the body,
together with the antenne (especially the upper pair)
and the peculiar sculpturation of the surface, afford the
best specific characters, and will doubtless sufficiently
separate the three species described by Mr. Goodsir
from any others that may occur.

Mr. Goodsir gives a series of details of the internal
anatomy of these animals, the nervous system consisting
of a supra-cesophageal ganglion, from which the nerves of
sense proceed, followed by four ganglions, united by
double cords, at the base of the four ciliated pairs of
legs, with three similar ganglia at the basis of the three
posterior pairs of feet, united to the preceding by a long
double cord. Two highly developed and distinctly
defined longitudinal muscles stretch along the dorsal
aspect of the elongated fourth thoracic segment, their
office being to enable the animals to erect the anterior
part of the body on the true formed legs, and affording
a purchase for the proper action of the powerful clawed

antenne.

ARCTURUS LONGICORNIS, 365

ISOPODA. ARCTURIDA.
NORMALIA.

ARCTURUS LONGICORNIS,

Specific character. Moderately slender. Four anterior segments of the
body strongly tuberculated. Upper antenne reaching to the tip of the
second joint of the inferior. Flagellum longer than the two preceding joints
together. Second, third, and fourth segments dilated: over the place of in-
sertion of the legs.

Length of the body, one inch.

Oniscus longicornis, Sownrsy, Brit. Mise. t. 19.

Arcturus longicornis. _WrEstwoop, in Trans. Ent. Soe. Lond. 1, 72, t. 16.
GuéRIn Ménév. Icon. R. An. Crust. t. 31, f. 2.
Minne Epwarps, Crust. iii. p. 124. Wuirn, Cat.
Brit. Crust. Brit. Mus. p. 63. Pop. Hist. Brit.
Crust. p. 221, pl. xii. f. 1. Gossz, Man. Mar.
Zool. 1, fig. 249.

Astacilla longicornis. Fiumine, Edin. Enc. vii. p. 502. Jounsron, in Lou-
don’s Mag. Nat. Hist. viii. p. 494, f. 44, adult ;
ix ps oO; 15, younr: DatyELL, Powers of
Creator, 1, p. 226, pl. Ixiii. figs. 1—4.

Leachia lacertosa. Jounston, Edinb. Phil. Journ. xiii. p. 220,

366 ARCTURIDA.

TuIs species is more robust than either of the two
following; it is also more strongly tuberculated, the
tubercles extending over the two segments preceding the
long one, which is somewhat transversely furrowed.
The head and terminal segments of the body are rather
broader in the male, but of an equal breadth throughout
in the opposite sex; the females are twice the size of
their partners, and of a whitish colour; the terminal
portions of the body are generally directed upwards.
The head is almost square, with the eyes prominent and
nearly circular: the anterior angles of the head are
produced in front of the eyes, forming a deep frontal
emargination, in which the anterior (upper) antenne are
inserted; these are not longer than the head, and have the
basal joint large, the next row short, and the flagellum
long, cylindric, and terminated by setae. The lower
antenne are nearly as long as the body, and very robust ;
the first joint is very short, the second rather longer, with
a deep external notch, the third about as long as the
head ; the two next are very long, each being about one-
fourth of the whole length of the body; the flagellum
is very short and finely serrated beneath, each being
eradually smaller, the last terminated by a minute acute
point; the antennz are usually carried in a downward
direction. The parts of the mouth are very minute and
delicate. The lip is transverse, rounded at the sides and
emarginate in front. The mandibles are small, horny,
broad, and armed with several teeth, without any palpi-
form appendage. The interior pair of maxilla are very
thin, transparent, and deeply ciliated. ‘The second pair
of these organs are larger, with a terminal lobe anda large
external sub-articulated appendage, the last division of
which is much larger than the rest, curved and ciliated

at the tip.

ARCTURUS LONGICORNIS. 367

The first three segments of the pereion are very short,
with a produced lateral margin (representing the coxe,
or first joint of the legs, and) concealing the base of the
legs, the first pair of which are alike in form, but shorter
than the others, and evidently perform the office of an
extra pair of foot-jaws; indeed, from the manner in which
this, as well as the three following pairs of feet, are carried
over the mouth, it is probable that they are all employed
rather as such than as locomotive organs. The very slender
structure of these three pairs of legs, which are all formed
alike and are strongly ciliated within, is also confirmatory
of this opinion. ‘The first pair of legs are also ciliated,
the ciliz arising in double rows, and being often bearded,
as is also the case with the three following pairs, in
which, however, only two of the hairs situated near the
extremity of the penultimate joint are thus bearded.

The fourth segment of the body is very long, occupy-
ing more than one-third of the whole length of the
animal, and being perfectly cylindrical in the males, in
which sex it is without any orifice or inferior lamella,
and is the narrowest part of the body; but in the female
it is as wide as the head, and furnished beneath with two
thin membranous plates, lapping over each other, and
serving as an envelope for the eggs, which are of a red
colour and kidney-shaped. The fourth pair of legs are
attached below the anterior angles of thissegment. The
three succeeding segments are short, rounded at the sides,
and respectively furnished with a pair of strong short
legs, well formed for prehension, having the last joint
terminated by a bifid hook. These legs are not ciliated,
and have a backward direction.

The tail, seen laterally, appears to consist of only two
segments, of which the first is almost globose, and the
second oval, terminating in a strong spine; seen from

3868 ARCTURIDA.

above, the first of these segments appears divided into
two, the posterior lateral angles being produced into
distinct pointed lobes: there is also a much less distinct
impression across the middle at the lower sides. The
terminal segment, also, has each side produced in the
middle into an acute angle, behind which the apex is
gradually acuminated.

The first segment of the tail is furnished beneath with
a pair of long thin plates, articulated to this and the
following joint at the outer edge, and which are capable
of shutting and opening like a pair of cupboard doors.
Each of them is terminated by a slender acuminated
process. On opening this pair of organs a most beautiful
apparatus is exhibited, consisting of no less than twenty
distinct pieces, arranged in five double pairs, serving for
respiration. At the base (in the male at least) is also
a pair of minute organs, terminated by two somewhat
cultrate plates. The first double pair of the respiratory
plates (which cover all the rest) succeed these appen-
dages, and are composed of a rather long and bent
flat foot-stalk, having on the outside four curiously bent
ciliated spines, and terminated by two long, delicate,
membranous, equal-sized plates, slightly scalloped at the
extremity for the insertion of the cilia, which are very
long and beautifully bearded ; the base of the internal
plate is also furnished on the outside with several long
bearded spines. The second double pair of plates are
nearly similar to the preceding, except that one of the
plates is very much narrowed. The three succeeding
double pairs of plates are much smaller and shorter, each
consisting of a pair of oval membranous plates, almost
destitute of cilize, attached to a short basal foot-stalk.

Detailed representations of most of the organs above
described will be found in the first volume of the “ Trans-

ARCTURUS LONGICORNIS. 369

actions of the Entomological Society,’’ plate ix., drawn
from specimens communicated by the late Dr. Johnston,
by whom they were captured in Berwick Bay. The
specimens figured by Sowerby were caught by Mr. T.
W. Simmons, entangled in nets, off Dysart, near Inch-
keith. The species was also captured by Mr. H. Goodsir
in the Frith of Forth, and in deep water in the German
Ocean, occurring more frequently than the two following
species; also by Dr. Clarke, off Cullercoats, on the
Northumberland coast: a colony of young animals
was taken, attaching themselves to the spines of
Echinus spherus, in the Channel, off Plymouth, by
ourselves (Dublin Nat. Hist. Rev., October, 1857,
p- 229).

Sir J. G. Dalyell, who kept some of these animals for
some time alive, gives the following particulars of their
habits and movements. “ Its peculiar organization gives
it a most unusual appearance, during repose grasping the
slenderest twig with its six hind feet, while all the body
is bent back beyond the point of fixture, so that the
creature actually seems broken-backed.

“Its motions are very singular, aggravated perhaps by
the apparently extraordinary proportions of the various
parts. The position, frequently assumed and long re-
tained, is adhering by the hind legs to any foreign
substance, with the head downwards.” Sir J. Dalyell
“‘never saw any specimen attempt to swim, to which,
indeed, its general form is quite adverse to the suppo-
sition. ‘The exuviation of a specimen took place during
the first week of October, when the shell was detached
in two portions, the posterior comprehending the six
hind legs.

“The season of propagation extends from March to
December. Ova appeared on June 14th, [beneath the

VOL. II. BB

370 ARCTURID.

pereion of] a female specimen. But the presence of a
diminutive white zoophyte injured the roe, which proved
abortive of progeny. A full-grown specimen was placed
in a suitable vessel on the 2lst of March; on the fol-
lowing day above sixty young were observed in the
vessel: all were pure white; they exceeded a line in
length, their black eyes were rather oval, and they re-
sembled their parent in general.

* On the 21st of May the appearance of another indi-
vidual attracted Sir J. Dalyell’s notice; it stood erect on
a piece of sponge, the body at right angles to the six
hind feet. The long antenne now stretched forward, as
usual with the species, but each appeared as thick or
thicker than the animal itself, and on a transient glance
it seemed invested by a coating of fur; however, this
unaccountable fact was easily explained by the appli-
cation of a lens. A numerous brood had been produced
in the night, whereof the whole, without exception, had
seated themselves on the antenna : yet the parent neither
testified impatience of their presence nor seemed to
suffer any uneasiness under the burden. All were very
pale or dingy white, none of them exceeding a line in
length. The young grew very rapidly; but as they
continued affixing themselves, they certainly proved an
annoyance which was ultimately fatal.” *

The animal dwells in the deep sea. Fine specimens
are rare.

* A specimen of A. Bafint is preserved in the collection of the British
Museum, in which the young are attached to the antenne of the parent. We
think, therefore, that we may assume that this mode of conveying their young
may be a peculiar feature in the instinctive habits of this animal. (See vig-
nette in p. 374.)

ARCTURUS INTERMEDIUS. 371

ISOPODA. ARCTURID.
NORMALIA.

ARCTURUS INTERMEDIUS.

Specific character. Upper antenne longer than the two basal joints of the
lower; the flagellum minute and obtuse; the fourth segment of the body
with a double row of small tubercles on each side of both the longitudinal
hinges of the ventral marsupial pouch, or ovigerous scale.

Length, four lines and a half.
Leachia intermedia. H. Goopstr, Edinb. New Phil. Journ. xxxi. p. 309,

pl. 6, f. 1. Wurtz, Cat. Brit. Crust. p. 64. Pop.
Hist. Brit. Crust. p. 222 (Arcturus int.),

Tue characters of this species were first pointed out
by the late lamented Harry D. T. Goodsir. It resembles
A. longicornis, but the peculiar prominent parts of that
species are more boldly thrown out. ‘The plates on each
side of the base of the antenne do not project, and their
infero-anterior angles are acute. The superior antenne
are longer than the first two joints of the inferior; the
first joint is globose, the second and third are slender,
and the flagellum is obtuse. The inferior antennz are
almost as long as the body; the first joint is as long as
the head, cylindrical, and having a ridge on its external
side ; the following joints are more slender, and the last

joint of the flagellyn is finely pointed.
BB 2

372 ARCTURIDA.

A double row of tubercles run down each side of the
inferior margin of the body, immediately above the inser-
tion of the legs; these tubercles are large and very promi-
nent on the three anterior and three posterior segments
of the body, but on the fourth they are not so prominent,
and are placed in a regular series on each side of the lon-
gitudinal hinges peculiar to this segment in the female.

The pleon bulges considerably, and then tapers sud-
denly to a point at its posterior extremity.

The animal is of a straw colour, spotted with brown.

Not having seen a specimen of this species, we have
been compelled to borrow our description and figures
from Mr. H. Goodsir’s Memoir on the genus above re-
ferred to. It was taken in the Frith of Forth, opposite
Anstruther, by Mr. H. Goodsir.

ARCTURUS GRACILIS. 3790

ISOPODA, ARCTURID 4.
NORMALIA.

ARCTURUS GRACILIS.

Specific character. Very slender, quite smooth, and destitute of tubercles ;
the upper antenne rather shorter than the first three joints of the lower; the
fourth segment of the body linear-cylindric, and not tubercled.

Length, seven lines.

Leachia gracilis. HH. Goovstr, Edinb. New Phil. Journ. xxxi. p. 310, pl. 6,
Arcturus gr. pate Cat. Brit. Crust. p. 64. Pop. Hist. Brit. Crust.
p. 222.

In this species the body is very slender and quite
smooth, without the tubercles, which are found in all
the other species. The plate which covers the base of
the antennz projects, and is rounded anteriorly. The
superior antennze are almost as long as the first three
joints of the inferior, the first joint being globular, the
second and third linear, each as long as the first; the fla-
gellum is equal in length, or longer, than the peduncle,
and the last articulation is minute and linear. The
inferior antennee are as long as the body, with the first
joint obsolete, the second slightly clavate, and the flagel-
lum strongly pectinated on their inferior edges. Both
pairs of antennee have a few bristles scattered over them.
The body is quite smooth, except a few scattered punc-
tures. The fourth segment is linear, cylindrical, and not

374 ARCTURIDA.

tuberculated. The anterior segments of the pleon
bulge very much, assuming the appearance of one of
the segments of the pereion, and from this it tapers very
gradually to a very sharp point.

The colour is rusty white, with brown spots.

Taken by Mr. Goodsir in the Frith of Forth, off Ans-
truther.

Our figure is taken from one of Mr. Goodsir’s type-
specimens preserved in the British Museum.

ARCTURUS WITH YOUNG ATTACHED TO THE ANTENNA. (SEE P. 370.)

IDOTEIDA. 375

Family—IDOTEID.

Tuts family, which contains the largest known Isopoda,
some of which are above four inches in length, is distin-
guished by the long, narrow form of the animals, by the
subequal segments of the pereion, by the fusion of three
or more of the segments of the pleon into one large
caudal shield, by the absence of uropoda or external
caudal appendages, by the conversion of the fifth pair of
pleopoda into a continuous operculum for the protection
of the branchial organs, by the nearly uniform size and
structure of the seven pairs of legs, and by the shortness
of the superior pair of antennae, which never exceed the
length of the cephalon. Some interesting exotic genera
of this family have been described by Mr. Dana, in his
great work on the American Exploring Expedition.

376 IDOTRA.

TISOPODA. ARCTURID.
NORMALIA.

Genus—IDOTEA. (Fabricius.)

Generic character. Lower antenne with four thickened cylin-
drical basal joints of moderate length, followed by a long multi-
articulate flagellum ; first pair of legs not larger than the second.
Pleon with two basal joints distinct, followed by a third semi-
distinct. The four posterior ones fused into one common caudal
plate.

THis genus (to which, with Professor Milne Edwards,
we refer the Stenosome and Sidurie of Leach, and the Lep-
tosome, Hebe, Oliskea, Zenobie, and Armide of Risso)
comprises an extensive series of species having the body
more or less flattened and elongate, the head broadly
truncate in front, the eyes small, lateral, and multi-
faceted. ‘The upper pair of antennez shorter than the
head, and very slender, composed of four joints, of which
the fourth is flattened, curved, and about the length of
the preceding joint, but having the appearance of being
composed of several articulations closely soldered to-
gether; the lower pair of antennz rarely exceed half
the length of the body, and are composed of five strong
basal joints, with a long, slender, multiarticulate
flagellum. The parts of the mouth are protected in
front by a large crustaceous lip (labrum), and behind by
the large pair of foot-jaws, each of which consists of a
strong basal stem, with an elongated lobe at its inner
extremity (bearing a small style-like appendage on the
middle of its inner edge), and with three large terminal
joints, strongly ciliated along their inner margin and at

IDOTEA. 377

the tip. At the base of each of the foot-jaws is attached
a large movable sub-oval plate. The mandibles are
robust, with a strong, curved, denticulated apical blade,
below which is a small movable plate, and a broad
truncated molar tubercle: they are destitute of an arti-
culated palpiform appendage.

The outer maxilla are very delicate, and terminated
by three oblong strongly ciliated plates ; the inner max-
illae have an elongated base and two thin terminal lobes
of unequal size, ciliated at the tips: the lower lip is
thin, with a deep incision in the middle of its anterior
margin (fig. * in page 379).

The legs are all formed for walking, rather than for
prehension or swimming; they are nearly of uniform
structure, the anterior pair being not larger than the
_ following; they, however, increase gradually in length to
the hind pair. In the female, the third and three follow-
ing pairs of legs bear at the base of each a large mem-
branous plate, folded beneath the body, forming a large
ovigerous sac. ‘The tail consists of a very large terminal
flattened shield, preceded by three very short segments, of
which the third is dorsally fused with the next succeeding.
In I, Entomon, a Baltic species, there are three distinct and
two apparent joints in this part of the body; in other
species, the soldering together more or less completely of
two or more of the short basal joints takes place, until in
I. appendiculata the tail appears to consist of only a single
large plate-like shield, traces of the articulations being
only visible at the lateral margins of the basal portion of
the joint.* The normal six-jointed structure of the tail
is, on the contrary, proved on the ventral surface of the

* The variations in the condition of these basal segments have furnished
Professor Milne Edwards with the characters for distributing the species into
various minor groups.

378 IDOTEA.

animal by the existence of five pairs of very delicate
branchial appendages (each appendage bears two plates),
and a strong outer pair (which are the terminal uropoda),
forming an operculum, opening laterally and shutting
over the branchial apparatus.

M. Polydore Roux, in his fine work on the Crustacea
of the Mediterranean, gives some interesting details of
the habits of these animals, which abound in places where
the sea has brought together masses of Alge in a state of
decomposition; here, at the depth of a foot or two in
tranquil water, they multiply rapidly, feeding voraciously
on dead fishes, mollusks, annelids, and other animal
matters, gnawing also the meshes of nets of fishermen.
They are essentially nocturnal, avoiding the light of day
by hiding themselves under marine plants, but never
under stones, and coming forth to feed after dark, some-
times in such vast numbers as, in company with small
Paguri, shrimps, &c., to consume a large amount of
the fish caught in nets. They crawl with facility at the
bottom of the sea, and swim easily by agitating the
plates of the tail. When the sea is rough, they seek
deep water, and are often thrown back by the action of
the waves. ‘They are much used by fishermen in the
Mediterranean as baits for different species of Psarus,
Perca, &c., which take them greedily, their capture being
distinguished in Provence under the name of Pesquo a
la baboué, the latter being the name applied to these ani-
mals as well as the parasitical Cymothoe. ‘This is done
by tying together bundles of Fucus ericoides, which are
sunk into the sea, and quickly adopted by the Idotee as
new places of retreat, and which at certain intervals are
drawn up, and the Jdotee, as well as great numbers of
Talitrus, called Mourpuros, Spheroma, and other Isopods,
shaken out.

IDOTEA TRICUSPIDATA. 379

ISOPODA. IDOTEID.
NORMALIA.

—=——

——

ie
Ee

IDOTEA TRICUSPIDATA.

Specific character. Elongate-subovate; lower antenne nearly half the
length of the animal. Segments of the pereion (except the first) with dis-
tinct_coxal plates (epimers) occupying the whole lateral margin. Pleon with
the first and second segments distinct, the third soldered in the middle to the
terminal large joint, which is more or less tridentate at the tip.

Length of the body, about one inch and a third.

Idotea tricuspidata. DrsmAREst, Cons. Crust. p. 289 (and pl. 46, f. 11%).
Roux, Crust. Medit. t. 29, f. 11, 12. Mitne
Epwarps, Crust. ili. p. 129, Wuuirs, B. M. Cat.
Brit. Crust. p. 65. Pop. Hist. Brit. Crust.
p. 223, pl. 12, f. 2. Gossz, Man. Mar. Zool. 1,

fig. 247.

Oniscus tridens. Scopou1, Ent. Carniolica. Oxivier, Enc. Méth. vi.
p. 26.

TIdotea Entomon. Pennant, Brit. Zool. 4, pl. 18, f. 5. Leacn, Linn.

Trans. xi. p. 364.

380 IDOTEIDA.

Idotea Basteri. Avpourn, Deser. of Savieny, Egypt. Crust. pl. 12,
f. 6. Rovx, Crust. Mediterr. t. 29, f. 1—10.

Idotea tridentata. LATREILLE, Con. Crust. et Ins. 1, p. 64. Lamarox,
H. Anim. s. Vert. 5, p. 269.

Idotea variegata. Rovx, Crust. Mediterr. pl. 30, fig. 1—9.

Armida bimarginata. Risso, H. n. Eur. merid. 5, 109.

Tus large species has the body of a very elongate-
oval form, slightly narrowed towards the extremity of
the tail, which is terminated by a strong central point,
having a smaller one on either side, which is, however,
often wanting, and the lateral angles rounded.

The lower antennz are nearly half the length of the
entire animal, the first joint very short and scarcely
visible from above; the four following joints gradually
increase in length, but decrease in thickness, and the
flagellum, which is rather longer than the five-jointed
peduncle, is slender, and consists of about twenty articu-
lations. The first segment of the body has the coxal
plate fused at the sides, but the six following have it
separated by a curved incision (indicating the epimeral
or basal joint of the legs), and which is more angulated
in the middle on the three posterior segments. The
anterior segment of the tail in the male is armed beneath
with two short horny points, directed backwards, and the
second pair of the branchial plates is also furnished, in
this sex (at least), with an elongated style, nearly as long
as the plates.

The tail consists, apparently, of four segments, of
which the first and second are quite distinct, although
very short, but the third loses all trace of articulation
in the middle of the back, so as to appear completely
soldered with the large terminal joint.

This species varies greatly in its colours and markings ;
generally, it is of a dirty greenish-grey, but often has a
pale longitudinal line down the middle of the back, or

IDOTEA TRICUSPIDATA. 381

on each side of the body, whilst other specimens are
marked, often irregularly, with large pale yellow or orange-
coloured patches on the body and tail. According to our
own experience, the colour of the animal is dependent
upon that of the weed on which it lives. Those that
live on the black fucus are generally very dark purple,
while those that we find on the green Alge are brightly
verdant; and it has always been our opinion that this
change was due to the food, as we have little doubt but
that they are vegetarians in diet, and that the depreda-
tions on fish is that of their marine companions.

SW | | Cy |

The accompanying woodcut exhibits different varieties,
showing the comparative paucity of the articulations in
the flagellum of the lower antennez in young individuals,
the length of the three individuals whose antennz are
delineated being indicated by the three adjoining lines,
whilst the other figures exhibit variations in the form of
the terminal segment of the body, with the length and
size of the respective specimens in the British Museum,
the first, third, and fourth of which are from Cornwall
(B. M. Coll. No. 50, 94, and 45, 139), and the large
second one from Cardiff (No. 56, 73). Some very fine
specimens taken off Cornwall have the caudal extremity
terminating in three well-defined cusps, as also one sent
to us by Mr. Gosse from Torquay.

Specimens having the extremity of the tail truncate,

382 IDOTEID.

with the lateral angles scarcely prominent, and the mid-
dle tooth only very slightly developed, have been con-
sidered as distinct species by M. Polydore Roux, who
has carefully figured a number of varieties; those
marked with pale spots being his J. variegata, and the
unicolorous ones his J. Basteri. We agree with Pro-
fessor Milne Edwards in considering them as mere
varieties.

Specimens of this species from the Cornwall and
Devonshire coasts, as well as from Scotland, are con-
tained in the collection of the British Museum. The
largest specimens we have seen (measuring one inch and
five lines and an inch and a quarter long) were forwarded
to us, the former by Mr. Byerley from the Cheshire
coast, the latter was taken off the Dudman, on the coast
of Cornwall. ‘There are also numerous specimens from
different Irish localities in the Belfast Museum, collected
by the late Mr. W. Thompson, Professor Allman,
Mr. Hyndman, Dr. Drummond, and Mr. Patterson ; Co.
Cork, Mr. Humphreys, “ Contributions to Fauna of Co.
Cork.”

Sir J. G. Dalyell has described and figured some varie-
ties of this species in his ‘‘ Powers of Creation,” vol. i.
p- 228, pl. Ixiii. fig. 5—9 and 10, under the names of
‘© Oniscus balthicus (Idotea marina),” and Entomon. “ Full-
grown specimens measure, from the tips of the antennz
to the posterior extremity, twenty-one lines in length.
Their colour is dingy or brownish-yellow, with three
or four white specks down the centre of the back; or it
is altogether of variegated hues, and some are mottled.
The variegated specimens are beautiful animals, espe-
cially when first appearing in their new shells.” He
observes that “this creature feeds voraciously, seizing
and carrying off prey in its fore limbs. It also devours

IDOTEA TRICUSPIDATA. 383

the smaller crustacea and mussels very readily. It swims
swiftly, and when at rest it generally clings to some sub-
stance admitting of its supine position ; exuviation ensues
at different seasons, the shell being always cast in two
portions.”

Mr. Robertson says that, like the herring, they are
observed to grow to a larger size in Loch Fyne than on
the neighbouring sea-coast.

384 IDOTEIDA,

ISOPODA. IDOTEIDA.
NORMALIA.

IDOTEA PELAGICA,

Specific character. Front of the cephalon slightly notched ; lower antennz
about one-third of the length of the animal, which is narrow, but with the
middle segments rather widest. Pleon with the first two joints distinct, the
third with the sides only distinct, united with the fourth in the middle ;
fourth joint large, with a slight keel down the middle, rounded at its ex-
tremity, with a small blunt tooth in the middle.

Length, half an inch.

Idotea pelagica. Leacu, Trans. Linn. Soc. xi. p. 365. Suppl. Enc. Brit.
i, 426. DxEsmAnust, Cons. Crust. p. 289. Samovurtuy,
Ent. Comp. p.106. Minne Epwarps, Crust. iii. p. 129.
Waitt, B. M. Cat. Brit, Crust. p. 65. Pop. Hist.
Brit. Crust. p. 223.

Tdotea marina. Fasricius, Ent. Syst. Suppl. p. 803 ?

Oniscus balthicus. Patuas, Spic. Zool. ix. t. 4, f. 6 ?

Rhetia pelagica, Leacu, MSS.

Our figures of this species are drawn from Dr. Leach’s
largest typical specimen in the British Museum Collec-

IDOTEA PELAGICA. 385

tion (No. 607a). It is certainly very closely allied to
I. tricuspidata. 'The body is covered with minute dots ;
the lower antennz are about one-fourth of the entire
length of the animal; the sides of the segments of the
body have the epimeral or coxal articulations as in J.
tricuspidata, and the basal segments of the tail are arti-
culated in the same manner as in that species, the union
between the third and fourth segments at the sides being,
however, more decided than in J. ¢ricuspidata. The
slight central keel at the end of this segment appears to
be the most important character.

Common on the Bell Rock in the Frith of Forth.
There are also specimens in the British Museum com-
municated by Col. Montagu. Specimens occur in Mr.
Thompson’s Irish Collection, taken at Belfast Bay in
March, 1841, one about a sixth of an inch in length, as
well as another, a quarter of an inch long, from the
stomach of a sheldrake, shot at the end of December,
also in Belfast Bay. It is also contained in Humphrey’s
“Contributions to the Fauna of the Co. Cork,” and we
have received it from the Eddystone Lighthouse. It is

probably common all round the coast in the laminarian
zone.

VOL. II. Cc C

386 IDOTEID A.

ISOPODA,. IDOTEID,
NORMALIA,

IDOTEA EMARGINATA.

Specific character. Hlongate-oyate, sub-convex, finely dotted. Front of
head slightly emarginate. Anterior lateral angles rounded, Coxe of the six
hind pairs of legs strongly developed on the dorsal side of the body. Pleon
with the third segment confluent in the middle with the fourth, which has the
two posterior-lateral angles produced, the space between them emarginate.
Lower antenne nearly one-third of the length of the animal.

Length, one inch and one-sixth.

Cymothoa emarginata. Faxsricrus, Ent. Syst. ii. p. 508.

Idotea emarginata. Fapricius, Ent. Syst. Suppl. p. 303. Mine
Epwarps, Crust. iii. p. 130. Cuvmr, Régne
Anim. (Ed. Crochard), t. 69, f. 2. Wurtr,
B. M. Cat. Brit. Crust. p. 65. Pop. Hist.
Brit. Crust. p. 224. Russo, Crust. de Nice,

p. 1385.
(2) Squilla marina. De Guer, Ins. vii. p. 522, t. 32, f. 11, 14.
Idotea excisa, Bosc. Crust. ii. p. 181. Larreriie, Hist. Nat.

Crust. et Ins. vi. t. 58, fig. 5. Var. (2)

Idotea peloponesiace. Rom. Crust. Med. t. 30, f£. 10.

Idotea estrum. Pennant, Brit. Zool. 4, pl. 18, f. 6. Laon,
Trans. Linn. Soc. xi. p. 565, DesMAnzst,
Crust. p. 289.

IDOTEA EMARGINATA. 387

Our figures of this species are derived from Dr. Leach’s
largest specimen, preserved in the British Museum (No.
1,000). It is very closely allied to I. fricuspidata, the
chief difference being that the central point of the ex-
tremity of the tail (of which a very slight trace may be
observed in certain individuals) does not extend so far
back as the prolonged lateral angles, and the epimeral
scales (coxee) of the six hind pairs of legs are widely
developed on the dorsal surface of the body, which is
covered with minute dark-coloured dots.

The basal segments of the tail are also formed as
in J, ¢tricuspidata, but the lower pair of antenne are
comparatively shorter.

Various specimens, captured in different parts of the
British coast by Col. Montagu and Dr. Leach, are con-
tained in the British Museum.

Mr. Robertson has sent it to us from Cumbray, and
the Rev. A. M. Norman from the coasts of Durham and
Northumberland.

It has also been taken at Port Patrick and Dundrum,
Ireland, by the late Mr. W. Thompson. Mr. W. P.
Cocks found this species among trawl refuse of fishing
boats, also in the stomach of fish at Falmouth. It is
common among weeds all round the coasts of Europe.

388 IDOTEIDA.

ISOPODA. IDOTEID.
NORMALIA.

IDOTEA LINEARIS.

Specific character. Long, narrow, with the sides of the segments nearly
parallel ; lower antenne nearly as long as the animal ; joinis of the peduncle
very robust; pleon with the terminal joint truncated, and tridentate at the
extremity, the lateral angles being more prominent than the central tooth.

Length, one inch and a half.

Oniscus linearis. Pennant, Brit. Zool. (edit. 1777), iv. t. 18, f. 2.

Stenosoma lineare. Leacu, Linn. Trans. xi. p. 366. Suppl. Enc. Brit.
i, 427. Desmarust, Cons. Crust. p. 290, t. 46,
f. 12. Guéixin Ménévittz, Exped. Morée, p. 49.
SAMOUELLE, Ent. Comp. p. 107.

Tdotea linearis. LATREILLE, Hist. Nat. Crust. et Ins. vi. p. 371.
Mitne Epwarps, Crust. iii. p. 132. Régne An.
(Ed. Crochard), Crust. pl. 69, f. 3. Wits, B. M.
Cat. Brit. Crust. p. 66. Pop. Hist. Brit. Crust.
p. 224,

Oniscus entomon. Baxter, Opuse. Subs. ii. t. 13, f. 2.

(2) Squilla marina. De Gerr, Ins. vii. t. 32, f. 11.

IDOTEA LINEARIS. 389

Idotea diodon. LarTreILur, Nouv. Dict. d’ Hist. Nat. xvi. p. 105.
GuiRIn Mén., Exp. Morée, p. 49.
Idotea viridissima. Risso, Crust. de Nice, p. 136, pl. 3, fig. 8.

Idotea hectica. Leacu, Edinb. Ene. vi. p. 404.

Stenosoma hecticum. Luacu, Linn. Trans, vii. p. 433.

Oniscus ungulatus. Patias, Spic. Zool. 9, 62, tab. 4, f. 11 (antennis
falsis ?)

Turs large species is at once distinguished by its parallel
and sub-depressed form, and the very robust joints of the
peduncular portion of the lower antenne, which organs
are nearly as long as the whole body ; the flagellum ter-
minated by two very minute articuli (c. x.); the front
margin of the head is strongly sinuated, with the lateral
lobes elevated ; the upper surface of the whole animal
is uneven. The second, third, and fourth segments of
the body exhibit a small portion of the epimera-like
base of the legs at their anterior angles, whilst the fifth,
sixth, and seventh joints have the posterior angles cut off,
and replaced by the same portion of the legs. The first
two segments of the tail are quite distinct, but the third
is only separated from the large terminal segment at the
sides, being completely soldered with it in the middle ; the
legs gradually but slightly increase in length, from the
first to the seventh pair, each being armed with a long
and strong simple hook-like finger. The tail occupies
one-third of the entire length of the animal.

The operculum reaches to the posterior margin of the
caudal segment, and has the second joint narrower than
the first, and terminating in a rounded extremity.

This species occurs in many parts of the British coast.

We have received specimens from Cumbray from Mr.
Robertson ; from Guernsey, Falmouth, and the coast of
Durham from the Rev. A. M. Norman; and we have
dredged it in Bigbury Bay, near Plymouth, on which
coast it is by no means common.

390 IDOTEIDA.

At Ilfracombe (British Museum). It was found under
stones in a cove west of the Castle, Falmouth, by Mr. W.
P. Cocks. It is often plentiful in the river Dee; we
have received it from Torquay, and from the Mumbles,
near Swansea, collected by Mr. F. Currey; from the Ber-
wickshire coast, by the late Dr. G. Johnston; also from
the coast of the County Down, Ireland, by the late Mr.
W. Thompson, and Co. Cork by Mr. Humphreys.

The figure of this species in the Crochard Edition of
the *“*Régne Animal,” although stated to be of the natural
size, is much too small for full-grown specimens, the
antenne too short, and the sides of the body not suffi-

ciently parallel to be a perfect representation.

MABLETHORPE,

IDOTEA PARALLELA. 391

ISOPODA, IDOTEID A.
NORMALIA.

IDOTEA PARALLELA.

Specific character. Narrow, subcylindric, with the sides of the pereion
parallel ; eyes placed at the base of slightly elevated anterior lateral angles
of the cephalon ; outer antennz not one-fourth of the length of the animal,
with a very short two or three-jointed flagellum. Pleon rounded at the ex-
tremity, which is subobliquely truncate, with the margin elevated. First
pair of legs larger than the succeeding.

Length, one-fourth to one-half of an inch.
Idotea chelipes. Costa, Faun. d. Regno d. Napoli. Crust. pl. 11, f. 2. Hops,
Cat. Crust. p. 26 (but not of Fabricius, Mant. Ins. i,

241. Ent. Syst. ii. 506, nor of Latr. Hist. N. Ins. et
Crust. vi. 372).

Tuts new British species will not enter into any of Prof.
Milne Edwards’ divisions of the genus, founded on the
structure of the basal segments of the tail, as our species
possesses three distinct although very short joints,
followed by a fourth joint, only indicated at the sides,

392 IDOTEIDA.

being soldered in the middle with the large terminal
joint, of which the posterior portion is subobliquely
deflexed, with the extremity rounded, without any
appearance of terminal or lateral points. The upper
antennee consist of four short but very robust joints, an-
gulated at the margins. The outer antenne are about
one-fourth of the length of the entire animal, composed
of a peduncle consisting of five robust joints, followed by
a flagellum composed of three or four joints more or less
closely soldered together. The legs are of nearly equal
size, except the first, which is the largest; the coxe or
epimeral portion of the second, third, and fourth pairs
appear dorsally as very narrow marginal plates, but in
the three posterior pairs they are much more developed
and visible from above, forming the lateral margin
of each joint, with the posterior angle produced into
a sharp elongated point. The first pair of legs are the
most robust, the third pair the longest, and the fourth
pair the shortest.

The animal is obscurely coloured, greyish-buff, with
three longitudinal dusky lines, one down the middle of
the back and the other two lateral.

This species appears to us to be very closely allied to,
if not identical with, the genus Cleantis of Dana (Expl.
Exped. Crust. p. 707, pl. 46, f. 9; the type of which
C. linearis was taken was from the stomach of a Silurus,
in the Rio Negro, North Patagonia), the characters of
which appear insufficient to warrant its separation from
Idotea.

We have obtained this species from Falmouth, taken
by Mr. Barlee, and from Polperro, whence it was sent to
us by Mr. Loughrin.

The Hopeian Collection contains numerous dry speci-
mens, to which the label “ Naples” is attached; they

IDOTEA PARALLELA. 393

agree entirely with Costa’s description and figure of
Id. chelipes in form and structure, as well as with another
specimen in the same collection labelled by Signor Costa
himself,

It is evident, however, that the C. chelipes of Fabricius
and Latreille cannot be identified with the animal before
us, the ‘* Cauda” tridentata of the Fabrician description
being entirely distinct from the remarkable character of
the extremity of the tail of I. parallela. Signor Costa
states of his species, *‘ Trovasi ne’ mari d’Inghilterra e di
Zelandia,” taking the habitat from Pallas by regarding
his species as the Oniscus linearis of Pallas’ “ Spic. Zool.”
fasc. 9, t. 4, f. 17 and 18. These figures are indeed bad,
but there can be little doubt that they represent small
and narrow specimens of J. tricuspidata, and we believe
Fabricius was correct in referring Pallas’ figures to his
C. chelipes, as Pallas describes the tail of his species as
obscurely tridentate, and indeed refers his linearis to
O. chelipes of his former work, from which probably Fabri-
cius had taken it up.

394 IDOTEIDA.

ISOPODA. IDOTEIDA.
NORMALIA.

IDOTEA ACUMINATA.

Specific character. Long and narrow. Lateral margins of the segments of
the pereion more or less rounded. Legs subequal. Pleon composed of a
single joint, elevated along its middle and produced into an obtuse point.
Colour pale, with three paler longitudinal streaks, edged with dusky.

Length, one-half to three-fourths of an inch.

Stenosoma acuminatum. Leacu, Edinb. Enc. vii. p. 433. ‘Trans. Linn.
Soc. xi. p. 3866. Prnnant, Brit. Zool. 4,
pl. 18, £. 8. (2)

Idotea acuminata. Wuirt, B. M. Cat. Brit. Crust. p. 66. Pop. Hist.
Brit. Crust. p. 224.
Idotea capito. RatHKE, Faun d. Krym, p. 384, pl. 6, £. 7—9. (2)

Our figure of this species was taken from Dr. Leach’s
type in the British Museum (No. 1,002). It is unfortu-
nately in very bad condition, having been pinned whilst
in a soft state, so that the sides of the body have curved
downwards, and our figure consequently represents the
animal as having its lateral margin much too continuous,

IDOTEA ACUMINATA. 395

instead of each of the joints being rounded at the sides,
and causing that part of the animal to be wider than its
tail.

The eyes are placed in the middle of the lateral
margins of the head, the anterior-lateral angles of which
are considerably porrected ; the outer antenne are about
half the length of the animal, with the flagellum multi-
articulate and longer than the peduncle. The epimeral
base of the second, third, and fourth pairs of legs are
visible dorsally on the anterior-lateral angles of the seg-
ments to which they respectively belong, whilst they are
more distinct in the three posterior pairs, and occupy
the posterior-lateral angles, which are rounded off. The
tail is narrower than any of the segments of the body,
and is nearly cylindrical, with the extremity pointed, the
middle of the back forming a slight ridge. This part of
the body appears to consist of a single joint, but on
carefully examining its sides (near the base), traces will
be observed of two incisions, indicating two obliterated
basal joints.

The British Museum specimens are from Dr. Leach’s
Collection, taken in Devonshire. Mr. W. P. Cocks
found it in trawl refuse, at Gwyllyn Vase, Falmouth ;
there are several specimens in fine preservation in
the Hopeian Collection at Oxford, labelled, “ South
West Coast of England,” and we have received it from
Cumbray, from Mr. Robertson of Glasgow.

This species is also given in the List of British /sopoda,
in the Reports of the British Association for 1860, p. 225.

396 IDOTEIDA.

ISOPODA. IDOTEIDZ.
NORMALIA,.

IDOTEA APPENDICULATA.

Specific character. Very narrow. Pereion with the lateral margins angularly
produced, with the slender legs attached close to their edges. Pleon lanceo-
late, and apparently only one-jointed.

Length, about an inch.

Leptosoma appendiculata. Risso, Hist. Nat. del? Eur. Merid. vol. v. p. 107,
t. 4, f. 28.

Idotea appendiculata. MitnE Epwarps, Crust. iii. p. 135. Watts,
B, M. Cat. Brit. Crust. p. 66. Pop. Hist.
Brit. Crust. 224.

Leptosoma lancifer. Leacu, MSS. in Brit. Mus.

Our figure of this species is drawn from Dr. Leach’s
specimen from Sidmouth, contained in the British Museum
collection. The body, somewhat irregular on its upper
surface, is narrowed and considerably flattened, with the
segments strongly produced and angulated at the sides,
the angles being formed (except in the first segment) by
the exposed epimeral or coxal joint of the legs. The

IDOTEA APPENDICULATA. 397

upper antenne have the basal joint short, but very much
dilated; the basal joint of the outer antennz is not
visible from above ; the four following joints are mode-
rately robust and nearly equal in length; the flagellum
is long, slender, and multiarticulate. The eyes are placed
in the middle of each side of the head, the anterior-
lateral angles of which are strongly produced and
rounded. The legs are slender and attached close to and
beneath the lateral angles of each of the segments of
the body.

The tail is considerably elongated, being about one-
third of the length of the entire animal ; it is lanceolate
in form, being more or less suddenly dilated at a short
distance beyond the middle. It appears to consist of
only a single segment, but faint traces of articulations
can be seen at each side near the base.

Besides Dr. Leach’s Sidmouth specimen, which is
labelled I. lancifer, the British Museum possesses speci-
mens from Ilfracombe, collected by Mr. Gosse, and we
have received it from Polperro from Mr. Loughrin.

The species is also given in the List of Jsopoda in the
Reports of the British Association for 1860, p. 225.

398 SPHHROMIDA,

The Sub-tribe SPHASROMIDEA,
ConsisTING of the single
Family SPH AZROMID/L,

is distinguished by the comparatively small size of the
species of which it is composed, which have the body
short, broad, and very convex, often contractile into a
ball, in both which respects they may be regarded as
marine representatives of the terrestrial wood-lice. The
foot-jaws are elongated, and in some species at least (e.g.,
Sph. serratum) they have the terminal joints not dilated at
the inner apical angle, so as to become palpiform; but
our numerous dissections prove that this character is not
constant in those species in which these joints are consi-
derably produced,—as in Spheroma Prideauxiana, Cymo-
docea emarginata, &c. The head is large and transverse.
The mandibles are robust and angulated at the extremity,
the tips formed into several distinct teeth, below which
is a strong molar tubercle. Externally, also, the mandibles
are furnished with a palpiform three-jointed appendage.
The first pair of maxillz consist of two long slender
lobes, the outer of which is most robust, and armed with
a short strong spine at its tip, whilst the inner is ter-
minated by long slender seta. The second pair of
maxille are very delicate and membranous, and termi-
nated by three nearly equal-sized oval ciliated plates,
forming the extremities of the three terminal joints. The
upper antenne are fixed at the anterior margin of the
head, which does not extend over them. All the antennz

SPH EROMIDA. 399

are inserted close together, in the middle of the front of
the head, and have a multiarticulate flagellum. The seg-
ments of the body do not exhibit, when viewed dorsally,
the epimera-like structure of the basal joints of the legs
observable in the Idoteide. In some few species the first
or the first two pairs of legs are subcheliform (as in the
genus Ancinus) ; but the third pair are always simple.
In the majority, all the legs are slender, and simply fermed
for walking, with a generally bifid terminal finger. The
basal segments of the tail are more or less rudimentary,
and in general soldered together more or less completely,
so as to form, apparently, only a single joint, which in
many species is furnished with large tubercles or spines.
The five pairs of branchial feet (pleopoda) are affixed
obliquely on the underside of the large joint of the tail,
which is deeply excavated for their reception. They are
very delicate and membranous in their structure, the
three anterior pairs being strongly ciliated on their
apical and external edges; and the second pair, in the
males, are furnished with an elongated slender-pointed
style. The terminal pair of the tail-legs (uropoda) con-
sist of two horizontal plates, of which the outer only
is movable, the inner one being either occasionally
obsolete, or soldered to the basal support. They are
attached at the sides of the terminal joint near its
anterior margin.

Professor Milne Edwards has proposed a separate
family (Spheromiens chelifers) for the reception of a re-
markable new genus (Ancinus), upon a specimen of un-
known locality contained in the British Museum, which
has the first two pairs of legs terminated by large and
strong hooks, and the body so flat as to be almost folia-
ceous. The inner plate of the lateral appendages of the
tail is wanting, whilst the outer is greatly elongated; but

400 SPH ®ROMIDA.

Dana has reduced this family to the rank of a sub-family,
and has separated Nisea and Campecopea, as a sub-family,
from the remainder of the genera.

The species of this family frequent the rocky shores
of the ocean, amongst Thalassiophyte, or under stones
and along the muddy banks of estuaries. Others, how-
ever, are generally found adhering to marine plants
floating on the surface of the sea, and some exotic
species eat deeply into water-logged timber, like Limnoria.
They are able to run and swim with considerable agility,
and afford a large supply of food to fishes.

SPHEROMA, 401

ISOPODA., SPHHROMIDA.
NORMALIA.

Genus—SPHAXROMA. — (Latreille.)

Generic character. Animal capable of rolling itself into a
ball. Cephalon small, with the eves dorsally situated at the
posterior angles. Antenne small. Pereion much broader than
the cephalon, with seven distinct segments, having the first
laterally anteriorly produced, so as to reach the anterior mar-
gin of the cepbalon. Coxe small. Pleon having all the
segments fused together, with the posterior margin entire.
Uropoda consisting of a peduncle that is posteriorly produced
into a long, flat, oval process, carrying a single ramus which
is articulated near the base.

THE genus, as originally designed by Latreille, was
co-extensive with the present family (with the ex-
clusion of the remarkable genera, Circeis (Australian),
Amphoroidea (Chilian), Cassidina and Ancinus (both of
unknown locality), four genera recently established by
Professor Milne Edwards. Dr. Leach, however, in his
Memoir in the ‘ Dictionnaire des Sciences Naturelles,”
divided it into seven genera, most of which have sub-
sequently been adopted by Latreille and other carcino-
logists; the typical genus Sphewroma comprising most
of those species which are able to roll themselves up
into a ball, at which time the lateral appendages of the
tail are not visible.

These animals are of small size, rarely reaching to the
length of half an inch.

VOL. It DD

402 SPHEROMIDSA.

The body is of a more or less oval form, very convex,
and rounded at each end, thus differing from the Cymo-
tho, which have the anterior part of the body much
narrowed. The head is broad and vertical, having a
frontal elevated transverse ridge which is continuous with
the lateral margin of the body. The eyes are very wide
apart, placed at the superior lateral angles of the head,
and received into an emargination on each side of the
first segment of the body. The antennez are inserted close
together in the middle of the anterior surface, on each
side of a small frontal prominence which is joined below
to the epistome; they fall back and are protected (when
unemployed) by being lodged within a groove beneath
the lateral margin of the head and anterior segment of
the body; the upper or inner pair are affixed at the sides
of a small triangular frontal prominence, and have a very
broad and flattened, nearly quadrate, basal joint, fol-
lowed by a second smaller one; the third as long as the
second, thin and cylindrical, followed by a short, slender,
articulated flagellum, consisting of about a dozen articuli.
The lower or outer antenne are considerably longer than
the upper, with the basal portion composed of four
moderately thickened joints and a multiarticulate flagel-
lum. The epistome is generally quite distinct from the
upper lip, and is produced above into a point, nearly
meeting the point of the upper triangular piece above
mentioned; on its lower edge it is very deeply emarginate,
receiving the base of the upper lip or labrum, of which
the anterior margin is nearly straight. The mandibles
are strong and horny, strongly angulated at the ex-
tremity, and terminated in that part by two slender
denticulated teeth, below which, on the inner margin, is
a large and strong molar tooth. Near the middle of the

SPHEROMA. 403

outer margin is affixed a triarticulated appendage.* The
inner maxillee consist of two nearly equal curved blades,
the inner of which is ciliated at the tip, and the outer
armed with strong spines. The outer maxillz are ter-
minated by three oval, very delicate plates, strongly
ciliated. The foot-jaws are large and strong, and close
the mouth; they are composed of a strong, basal joint,
followed by a small joint, and are furnished with a large
triangular inner lobe, and terminated by four strong
joints of nearly equal length, but gradually diminishing
in thickness, and strongly ciliated. In some of the
species these four joints are internally produced into
a large lobe; the lower lip is rounded at the sides
and very deeply notched in the middle of the fore-
margin.

The first segment of the body is larger than the fol-
lowing, and strongly produced backwards at its posterior
lateral angles; the six following segments are marked at
the sides with an impressed oblique line indicating the
coxze or epimeral base of the legs; the seventh segment
of the body is very short, and does not extend outwardly
so far as the first segment of the tail (pleon), which is
marked on each side with two transverse striz, which do
not unite in the middle of the back, but which’represent
three segments coalesced together. The terminal joint is
large, and marked at its base with a rather deep transverse
channel. The legs are of nearly equal size; they are
terminated by a bifid finger. The tail-plates (pleopoda)
consist of six pairs, five folding obliquely upon each
other, and received in a deep excavation on the underside
of the tail, of which the two last are furnished with bran-

* Savigny (Egypte Crust., pl. 12, f. 1 i,) represents the middle joint as
divided into two, probably arising from the appendage having been twisted
in this part in the specimen dissected by him.

DD 2

4.04 SPH EROMID®.

chial organs; the last or sixth pair are crustaceous, and
terminated by two nearly equal oval plates, of which
the outer is movable, and folds under the inner, which is
soldered to the basal support.

They are vegetable feeders, and some species have
recently been described by Dr. Fritz Muller, from the
Brazils and Madras, which were found living as extensive
perforators in submarine timber.

STUDLAND BAY,

SPHAROMA SERRATUM. 405

ISOPODA. SPH M@ROMIDA.
NORMALIA,

A
j p

SPHH ROMA SERRATUM.

Specific character.—Smooth, oval, very convex; pleon rounded at the
extremity, which is entire ; outer division of the terminal appendages of the
pleon slightly serrated, extending as far back as the extremity of the last
segment,

Length, about half an inch.

Oniscus serratus. Fasricius, Mant. Inst. 1, p. 242.

Cymothoa serratum, Faprictus, Ent. Syst. ii. p. 510.

Spheroma serrata. Leacu, Edinb. Ene. vii. p. 405. Suppl. Enc. Brit.
1427. Trans. Linn. Soc. xi. p. 368. Dict.
des Sci. Nat. xii. p. 346. Samouvztix, Ent. Com-
pend. p. 108. Desmarzst, Cons. Crust. p. 301,
t. 47, f. 3. Latrerun, Ency. Méth. x. p. 458.
GuérIn Méyev., Icon. R. An. Crust. t. 30, f. 1.
Minne Epwarps, Crust. iii. p. 205, t. 31, f. 11.
Wuirte, B. M. Cat. Brit. Crust. p. 75. Pop. Hist.
Brit. Crust. p. 245, pl. xiii. f. 6. Gossz, Man.
Mar. Zool. i. f. 235.

406 SPH ZEROMIDA.

Oniscus globator. Pauas, Spic. Zool. ix. t. 4, f. 18.

Spheroma cinerea. Bosco, Hist. Crust. 11, p. 186. Larrermin, Hist. n.
Crust. et Ins. vii. p. 16. Genera Crust. et Ins. 1,
p. 65. Saviany, Exped. Egypt. Crust. t. 12, f. 1.

Tuis is the largest British species, sometimes attaining
the length of half an inch. It is very convex, and has
the surface of the body quite smooth. It is broadly
ovate, the greatest breadth being in the middle of the
animal. The front of the head is nearly straight, and
elevated into a thin marginal line, in the middle of which,
beneath, is affixed the small triangular piece between the
base of the superior antenne, the two dilated basal joints
of which do not extend to the inner angle of the eyes,
whilst the flagellum extends slightly beyond the base
of the flagellum of the lower antennze. The seventh
segment of the body (pereion) is very short, and on each
side, near the extremity of its posterior margin, is a
small, somewhat triangular incision, which is filled up by
a minute but distinct rudimental portion of the real first
segment of the tail, of which no other portion is visible ;
the first apparent segment consisting of three joints, of
which incisional traces may be observed in the two lines
on either side, which are quite lost in the middle of the
disc, which is quite smooth, simple, and entire. The ter-
minal segment is very convex; it is narrowed on each
side for the reception of the flat curved inner lobe of the
lateral appendages (uropoda), beneath which the outer
lobe is generally concealed ; thus forming, with the ter-
minal segment of the tail, nearly a semicircle, of which
the posterior extremity is slightly truncate. The outer
margin of the lateral appendages is furnished with five or
six serrations. Sometimes the posterior extremity of the
tail is somewhat elongated into a flattened and more
truncated plate, in which state it appears to have been

SPHHROMA SERRATUM. 4.07

formed into a distinct species, Sph. trigonum, by Risso
(Crust. de Nice, p. 14°7).

When alive, the body is ashy coloured or whitish,
varied with reddish and dark grey; the eyes black; the
antenne fulvous; the legs ashy, with fulvous claws tipped
with black.

Young individuals, measuring not more than two lines
in length, have the outer edges of the side appendages of
the tail (uropoda) entire, and not serrated.

This species lives in numerous societies under stones
and amongst the pebbles and gravel of the coast; and is
found on the English and French coasts of the English
Channel, from Kent to Cornwall, and in the Medi-
terranean. We have dredged fine specimens in Plymouth
Sound in the month of August. Dr. Kinahan obtained
it in the River Lagan, Belfast, and in the River Dodder,
Dublin. We have observed quantities in the brackish
streams on Loughor Marsh, near Swansea, mixed with
Palemon, Carcinus, and Talitrus.

408 SPH EROMIDA.

ISOPODA. SPHAROMID.
NORMALIA.

SPHZROMA RUGICAUDA.

Specific character. Body smooth, moderately convex ; tail rounded and
entire at the extremity, its upper surface rugose ; outer division of its lateral
appendages oval and entire.

Length, four-tenths of an inch.

Spheroma vugicauda. Leacu, Edinb. Ene. vii. pp. 405 and 433. Trans.
Linn. Soc. xi. p. 369. Dictionn. Sci. Nat. xii.
p. 846. Dysmarust, Cons. Crust. p. 300. Minne
Epwarps, Crust. iii. p. 207. Jounston, Zool.
Journ. 3, 180. Wuitr, B. M. Cat. Brit. Crust.
p. 75. Pop. Hist. Brit. Crust. p. 245.

‘THis species closely resembles the preceding, but it is
less convex, and is easily distinguished by the rugose or
granulated upper surface of the tail, and sometimes of
the hinder segments of the body, and the simple outer
margin of the external division of the uropoda.

The head is narrower than the following segment,

SPHHROMA RUGICAUDA. 409

having the eyes on each side, which do not touch the
external margins, and are not quite round in their out-
line; the superior antennz are about half the length of
the inferior; the flat basal joints are punctate; the
segments of the body are nearly equal, short, and con-
vex; the terminal segment of the tail is rounded behind
and obliquely truncate at the sides; the two plates of 3
its lateral appendages are equal, of a linear-oval shape,
neither ciliated nor serrated on the outer edge.

When alive, it is of an ashy colour, with dots and
streaks of black, and is often marked with a light
coloured stripe down the back; it is much more active
than the preceding species, swimming with considerable
velocity and often on its back, and contracting itself into
a ball when alarmed; it can live a long time out of
water.

It occurs on the coasts of France and Great Britain.
Dr. Leach took it very abundantly on the island of Ulva,
near Mull (one of the Hebrides), and also at the mouth
of the River Tamar, in Devonshire. Dr. Johnston also
sent it to us from Berwick-upon-Tweed, and Dr. Kina-
han dredged it at Blockhead, in Belfast Bay.

410 SPHAROMIDA.

ISOPODA. SPH HROMIDA.
NORMALIA.

h

SPHHROMA HOOKERI,

Specific character. Upper surface nearly smooth ; terminal segment of the
pleon rounded at its extremity; the two last segments of the pleon bicari-
nated ; the carinz but slightly elevated ; those of the terminal segment some-
times interrupted, so that each forms two tubercles.

Length, one-third of an inch.

Spheroma Hookeri. Luacu, Edinb. Ene. vii. p. 433. Trans. Linn. Soe. x.
p. 869. Dict. Sci. Nat. xii. p. 345. Desmaxest,
Cons. Crust. p. 800. Mitnn Epwarps, Crust. iil.
p. 206. Wuirr, B. M. Cat. Brit. Crust. p. 76. Pop.
Hist. Brit. Crust. p. 245.

THIs species was found by the late Sir William Hooker
on the coast of Suffolk, and was described by Dr, Leach
(to whom it had been sent, together with his entire col-
lection of crustacea, by that gentleman), as being ashy-
grey or reddish coloured, dotted with black points; the
antennze ashy. In one individual the ‘small posterior
ventral plate” had its extremity slightly serrated, and the

SPHEROMA HOOKERI. 4\1

surface of the tail bicarinated, as mentioned in the spe-
cific character given above.

Mr. A. White states that the Rev. Alfred Norman had
found it at Clevedon, and in Guernsey.

We have not been able to discover the type specimens
of this species in Dr. Leach’s collection in the British
Museum, and give the above characters from his descrip-
tion. The accompanying figure is taken from specimens
which we have no doubt belong to this species, and which
were captured by the late Mr. W. Thompson in Belfast
and Strangford Loughs.* These are more elongated than
Sph. serratum, and the upper surface of the body is
slightly granulated on the posterior segments, as well as
the tail, the last segment of which bears two well-marked
carine, not quite parallel, the extremity of the segment
being rather flattened, elongated, and rounded at the tip,
without any trace of notch at the sides. The two plates
of the lateral appendages of the tail are elongate-ovate,
and entire. They extend backwards as far as the pro-
duced extremity of the terminal segment.

Whilst this sheet has been going through the press we
have received specimens of this species from Mr. Slade,
who found them at Bexhill, near St. Leonard’s, in
brackish water affected by land drainage.

* One of these individuals, labelled Belfast, is mixed up with specimens
of S. serratum in the British Museum collection.

412 SPHZEROMID®.

ISOPODA. SPH #ROMIDA.
NORMALIA.

SPHHROMA CURTUM.

Specific character. Upper surface smooth ; second, third, and fourth seg-
ments of the pereion terminating laterally in a sharp point on each side ; the
three following more oval at the lateral extremities. Terminal segment of
the pleon with two large rounded and broad tubercles; extremity produced in
the middle into an obtuse point, with a notch on each side ; both plates of
the lateral appendages of the tail obliquely truncate.

Length, one-fourth of an inch.

Spheroma curtum. Leacu, Dict. Sc. Nat. xii. p. 345. Desmarust,
Cons. Crust. p. 299. Minne Epwarps, Crust.
jii. p. 209.

Var. Spheroma Grifithsii. Luacn, MSS. in Brit. Mus.. W. THompson, in
Ann, Nat. Hist. xx. p. 246. Wuuts, B. M.
Cat. Brit. Crust. p. 76.

THIs species is now for the first time described and
figured from Dr. Leach’s typical specimen in the British
Museum, named by him Sph. Grifithsii, which we con-
sider to be a fully developed individual of Sph. curtum,

SPHEROMA CURTUM. 413

and from which the following description is made, as well
as the accompanying figures are taken.

The upper surface of the animal is quite smooth. The
head is produced into a small, somewhat hastate point in
front. ‘The upper antenne have the very large flat basal
joint affixed by a small rounded rotule; the second joint
of these antennz is transversely oval, followed by two
slender joints, and about eight articuli, forming the flagel-
lum. The lower antenne are but little longer than the
upper. The first segment of the body is dilated at the
sides ; both the anterior and posterior angles being pointed
and produced. The three following segments are pointed
at the extremity of the lateral margins; and the three
terminal segments have the lateral angles more ovate.
The tail has the first segment distinctly indicated by
a transverse slightly impressed line, extending across
the whole breadth of its base, the middle portion of
the line extending rather more backwards than the side
portions, which reach only to the inner portion of the
terminal lateral lobe of the seventh segment of the body.
The second, third, and fourth segments of the tail are
confluent in the middle of the back, and in certain lights
the posterior margin of this confluent mass exhibits
traces of two small tubercles, wide apart, in front of the
two large dorsal rounded tubercles of the terminal seg-
ment. The last segment has the middle of its extremity
produced into an obtuse point, which is slightly notched
on each side; and on looking at the animal from behind
this part appears semitubular, the produced apex forming
asmall arch. 'The lateral appendages of the tail do not
extend so far back as its extremity, and they have both
divisions obliquely truncate, and very slightly emarginate.
In the above woodcut the right-hand figure v represents
the right-hand portion of the hind part of the body and

414 SPHHROMIDA.

tail seen from above, whilst in the figure P is represented
the under surface of the tail, omitting the membranous
respiratory plates (pleopoda),.

Fully developed specimens above described were found
at Torbay by Mr. Griffiths, after whom it was named by
Dr. Leach; and the late Mr. W. Thompson found several
closely packed within the shell of a Balanus fixed on a
Modiola vulgaris in Belfast Bay ; some specimens in
the British Museum are from Lamlash Bay, in the Isle
of Arran.

The smaller individuals, as we believe them to be,
which served Dr. Leach for his vaguely described Sph.
curtum, differ only from the preceding in having the
tubercles of the terminal segment of the tail scarcely
elevated, and the body somewhat narrower. Dr. Leach
placed the species in his section “ with the terminal seg-
ment of the abdomen having its extremity furnished
with two small notches,” and having “the third seg-
ment of the abdomen widely notched posteriorly, whilst
the last segment is pointed at its tip.’ Professor Milne
Edwards is unable to comprehend this apparently contra-
dictory description. The fact is, however, that the wide
notch of the third segment of the tail is produced by the
two angular lateral incisions towards the sides of the
posterior margin of the confluent basal joints, whilst the
extremity of the tail itself is obtusely pointed, with a
notch on each side of the obtusely projecting extremity.
The upper surface of the terminal segment exhibits only
two very slight elevations, in the place of the rounded
tubercles of the larger variety above described. The
lateral appendages of the terminal segment of the tail
are comparatively small, and obliquely truncated.

The smaller variety was first taken by Montagu on the
south-west coast of England.

SPHHROMA PRIDEAUXTIANUM. 415

ISOPODA. SPHA#ROMIDA.
NORMALLIA,

SPHMROMA PRIDEAUXIANUM.

Specific character. Oblong-ovate ; cephalon very broad. Segments of the
pereion entire, convex; pleon with the penultimate joint produced into an
angulated lobe on each side of the posterior margin ; last joint with two
oblong carinze in the middle of the upper surface; extremity produced into an
obtuse point, slightly notched on each side.

Length, one-third of an inch,

Spheroma Prideauxianum. Luacu, Dictionn. Sci, Nat. xii. p. 345. Dxs-
MAREST, Cons. Crust. p. 299. Minne
Epwarps, Crust. iii. p. 209. W. THompson,
Ann. Nat. Hist. xx. p. 245. Wuurts, B. M.
Cat. Brit. Crust. p. 76.

Our description and figure of this species are taken
from Dr. Leach’s type in the British Museum. It is
more oblong than the preceding; but has the two plates
of the lateral appendages of the tail short, the inner one
being obliquely truncate. The upper antennz have the
two basal joints broad and flat, the third joint slender,

416 SPHEHROMID®.

followed by a slender nine-jointed flagellum. The lower
antenne are slender, having the four basal joints slender,
the first and second shorter than the third and fourth,
which are equal. The flagellum is slender, and consists
of seveuteen articulations. The foot-jaws differ from
those of the typical species, in having each of the three
intermediate joints dilated into an internal flattened lobe,
a character which, in conjunction with that of the short
plates of the lateral appendages of the terminal segment
of the body, seems to indicate a more than specific
distinction, and which is probably also found in Spf.
Griffithsii, which appears to be congeneric. The five pos-
terior segments of the body have their lateral portions
separated by a slender impressed line (indicating the basal
division of the legs attached to each of them), and the
hind segment of the tail is marked with two elongated
carinee ; its extremity is obliquely rounded, with a small
notch on either side.

We regret that the paucity of individuals which we
have been able to examine of this and the preceding
species, and its supposed variety Sph. Griffithsii, do not
allow us so satisfactorily as we could have wished to
determine the real position of the latter, which may pos-
sibly belong to the present species, having the tubercles
on the tail nearly obliterated.

Dr. Leach obtained his unique specimen from Mr. C,
Prideaux, who took it on the west coast of Devonshire.

We possess a specimen of the species of Spheroma
figured by Savigny in the great work on Egypt. Crust.
pl. 12, f. 4, distinguished from Sph. serratum by its more
elongated form, flattened triangular head, and especially
by the semicircular notch at the extremity of the tail.
We believe it to be British; but being unable to speak
with precision on the subject, we have omitted to figure
it in the present work.

ry

DYNAMENHE, 417

ISOPODA, SPHAROMIDA.
NORMALIA.

Genus—DYNAMENE. (Leach.)

Generic character. Smooth, not bristly; contractile into a

ball, with the lateral appendages of the pleon exposed;

terminal segment having a deep excavation in the middle of

the posterior margin. Superior antenne with the basal joint
oblong, not flattened, and the second joint sub-triangular.

THE species of this genus have much the appearance
of small Sphzrome, but are distinguished from them
by the slit at the extremity of the tail, which is simple,
without a central tooth, as in Cymodocea, from which
they also differ in the smooth clean aspect of the dorsal
surface, and in the structure of the basal joints of the
superior antenne.

The body is very convex, smooth, and destitute of the
bristles which are so conspicuous in the Cymodocee.
The upper antennz, when at rest, are concealed beneath
a slightly produced margin to the front of the head; the
basal joint is oblong and but slightly flattened, the
second joint is triangular-shaped, and the flagellum is
multiarticulated ; the lower antennez are more slender at
the base than the upper, with four nearly equal basal
joints, and a moderately long multiarticulate flagellum.
The mandibular appendage has the two terminal joints
subequal and strongly setose on the inner edge ; the apex
of the mandible is armed with several minute denticulated
teeth and a slender setigerous lobe in the middle of the
apical edge; the foot-jaws have the intermediate joints

VOL. II. E E

418 SPH HROMID A.

moderately produced at the inner angle. The maxillez
are very delicate and thin membranous plates, setose at
the tip. (In our figures of the second maxille in
D. rubra and Montagui, only one of the lobes was ob-
served on dissection.) The legs are moderately robust,
terminated by a strong hook, having a small tooth on its
inner edge. The tail is terminated by a simple slit, not
enclosing a central tooth, and the lateral appendages have
the outer lobe exposed.

The species are of small size, and agree in their habits
with the Sphzrome. They frequent rocky coasts,
preferring them on account of the small rock-pools
which abound in such situations, in which they reside.
They are also found among Thalassiophyte at low water.
They swim with much quickness and elegance, turning
themselves over on their backs and executing various
evolutions with great agility. They are probably com-

mon all round our coasts.

DYNAMENE RUBRA. 49

ISOPODA. SPH EHROMIDA,
NORMALTA,

(ip.
\\I

ti
(tt) (ly
( \\1 {
N

DYNAMENE RUBRA.

Specific character. Narrowly ovate, with the sixth segment simple ; outer
plate of the uropoda shorter than the inner; central excavation in the
terminal margin of the pleon of equal width throughout. Colour reddish
or greyish buff, with black or red specks.

Length, one-fifth of an inch.
Oniscus ruber. Montacu MSS.
Dynamene rubra. Leacw, Dictionn. Sci. Nat. xii. p. 344. Drsmanzst,
Cons. Crust. p. 298.
Cymodocea rubra. Mitnn Epwarps, Crust. iii. p. 216. Warts, B. M. Cat.
Brit. Crust. p. 77. Pop. Hist. Brit. Crust. p. 247.
THIS species is rather narrow in form, with the sides
of the body but little arched; the sixth segment is con-
siderably larger than the seventh, and is unarmed at its
posterior margin; the terminal segment of the tail is
large and very convex, and is terminated by a longitu-
dinal slit, which is nearly of equal width throughout its
EE 2

420 SPH HZROMIDA.

entire length. The outer plate of the lateral appendages
of the tail is considerably smaller than the inner, which
is broadly ovate. When alive, the animal is of a reddish
colour, being covered with numerous red dots, or greyish
buff with black specks; the articuli of the flagellum of
the antenne are tipped with red, and the anterior seg-
ments of the body have a red transverse line beyond the
middle of each.

It is stated by Dr. Leach that this species is very com-
mon on the south-west coast of England, where it was
first taken by Montagu. We have taken it at Firestone
Bay, near Plymouth. It has also been taken at Cumbrae,
in the Firth of Clyde, by the Rev. A. Norman; and at
Bangor, in Ireland, in September, by the late Mr. W.
Thompson ; and probably occurs all round our coast.

DYNAMENE VIRIDIS. 421

ISOPODA., SPHH#ROMIDA,
NORMALIA.

DYNAMENE VIRIDIS.

Specific character. Broadly ovate ; sixth segment simple ; terminal seg-
ment of the pleon centrally very convex, with an outer flattened margin, and
a terminal excavation, which is widest at its base. Colour green. Outer
plate of the uropoda rather smaller than the interior.

Length, about one-fifth of an inch.

Dynamene viridis. Luacu, Dictionn. Sci. Nat. xii. p. 344. Desmarusz,
Cons. Crust. p. 298.

Cymodocea viridis. Minye Epwarps, Crust. ili. p. 216. Wuitr, B. M.
Cat. Brit. Crust. p. 77. Pop. Hist. Brit. Crust.
p. 267.

Tus species is distinguished from the preceding by
its broadly ovate form, and from the following by the
sixth segment of the body being destitute of an in-
cumbent spine; the dorsal surface is even, and destitute
of ciliz. ‘The upper antennz are separated from each
other at the base by a small oblong lobe; the second

422 SPH ZROMIDA,

joint is obconical, and the flagellum multiarticulate. The
last joint of the tail is centrally very convex, but the
outer margin, both laterally and posteriorly, is flattened,
and the terminal slit is considerably widened at its base ;
the extremities of the sides of the slit sometimes closely
approximating or touching each other; the lateral ap-
pendages have the outer division rather smaller than the
inner. The dactylos of the feet is armed on its inside
with a strong tooth. Our figure c represents the head
seen from the front, the oral appendages are therefore
represented as foreshortened.

In the young state, the sides of the terminal slit of the
tail gape to a considerable width at their extremities.

Montagu and Leach found this species in company
with the preceding in great quantities, and Mr. W.
Thompson took it at Lahineh, in Co. Clare, Ireland.

DYNAMENE MONTAGUI. 4.23

ISOPODA. SPH#ROMIDA.
NORMALIA,

DYNAMENE MONTAGUI.

Specific character. Rather narrow ; sub-parallel. Sixth segment of the
pereion produced in the middle of its hind margin into a triangular lobe ;
outer plate of the uropoda longer than the inner,

Length, one-fourth of an inch.

Dynamene Montagui. Leacu, Dict. Sci. Nat. xii, p. 344. DEsmarust,
Cons. Crust. p. 298.

Cymodocea Montagut. Minne Epwarps, Crust. iii. p. 215. Wurtz, B. M.
Cat. Brit. Crust. p. 77. Pop. Hist. Brit. Crust.
p. 266,

Tuts species is rather narrow, with the sides of the
body somewhat parallel. The dorsal surface is marked
with minute slightly impressed punctures. The sixth
segment is produced in the middle of its hind margin

4.24 SPH ZROMIDSA.

into a flattened triangular lobe, the centre of which is
longitudinally impressed. The hind margin is also fur-
nished on each side (about half way between the middle
and lateral angles) with a minute but prominent tubercle.
The terminal segment of the tail is very convex, with a
transverse bipartite tubercle in the middle; the terminal
margin is incised in the centre with a small longitudinal
slit. The outer plate of the lateral appendages of the
tail is narrowly ovate, and pointed at the tip; it is
somewhat longer than the inner lobe, which is slightly
obliquely truncated.

This species was taken by Dr. Leach on the western
shores of Devonshire, and named in honour of Colonel
Montagu, whose researches on marine zoology added so
greatly to our knowledge of the native fauna. We
have taken it among Fuci, between tide marks on the
coast of South Wales, South Devon, and Cornwall.
It is probably tolerably common on rocky beaches all
round our coast. It is generally found associated with
Dynamene rubra and Nesa bidentata.

CYMODOCEA. 4.25

ISOPODA. SPHA#ROMIDA.
NORMALIA.

Genus—CYMODOCEA. (Leach.)

Generic character. Not capable of being completely rolled
into a ball. Pleon very rugose, deeply excavated at the tip,
with a lobe or tooth in the middle. Uropoda with the plates
elevated obliquely, so as not to shut under each other, the
inner plate being a process of the peduncle.

THESE species are easily distinguished by the very
rugose and setose segments of the tail, which is terminated
by a deep notch, within which is a produced central plate
or lobe. The body is more parallel at the sides than in
Spheroma, all the segments being simple. These charac-
ters will at once distinguish the genus both from Spheroma
and Dynamene, which latter has been united with it as a
second section by Professor Milne Edwards.

The head is nearly as broad as the broadest part of the
body. ‘The flagella of both pairs of antennz are multi-
articulate. The penultimate segment of the tail (forming
the posterior margin of the consolidated basal mass) is
prolonged in the middle and emarginate, the terminal
segment bearing in the centre of its upper surface a com-
pound tooth or spine, and the extremity of the tail is
deeply notched, with a short horn or lobe in the middle
of the notch. The foot-jaws have the intermediate joints
prolonged on the inner margin, the extremity of the lobes
thus formed being thickly ciliated. The lateral appen-
dages of the tail have two small lobes, which are strongly
ciliated with stiff short hairs, which also are thickly
scattered upon the upper surface of the segments of the
tail.

426 SPH MROMID A.

ISOPODA. SPHMROMIDA.
NORMALIA.

CYMODOCEA TRUNCATA.

Specific character. Pleon slightly granulated ; fourth segment with two
small tubereles in the middle of the hind margin; terminal segment with
two larger dorsal tubercles, followed by a central oval, very setose tubercle,
and three terminal spines, which are truncated.

Length, five-twelfths of an inch.

Oniscus truncatus. Montacu MSS. in Brit. Mus.

Cymodocea truncata. Luacn, Edinb. Enc. vii. p. 433. Trans. Linn. Soc.
xi. p. 303. Suppl. Enc. Brit. i. 427. Dictionn. Sci.
Nat. xi. p. 843. SamovE ie, Ent. Compend. p. 108.
DrsmAREsT, Cons. Crust. p. 297. Minne Epwarps,
Crust. lii. p. 214. W. Tompson, in Ann, Nat.
Hist. xx. p. 246. Wuirn, B. M. Cat. Brit. Crust.
p. 76. Pop. Hist. Brit. Crust. p. 246. Gossz,
Man. Mar. Zool. 1, fig. 236.

Our figure of this species is made from Dr. Leach’s
typical specimen preserved in the British Museum. It
is very nearly allied to the following species, but it is
much less rugose, and the form and size of the lateral
appendages of the tail are different in the two species.

CYMODOCEA TRUNCATA. 427

The body is somewhat cylindrical, with the sides nearly
parallel. The entire length of the animal is about two
and one-fourth times the width of the middle of the
body. The antennz are short, the inferior being about
as long as the breadth of the head; the superior have
the basal joint (omitted in our upper left-hand figure)
strongly punctured. The tail has the upper surface
irregular and setose. The basal portion has the middle
of the posterior margin extended backwards, and emar-
ginate, with two small tubercles near the angles of the
emargination. ‘The large terminal joint has two large
oval setose tubercles in the middle of the upper side,
followed by a slightly convex lobe, on which the bristly
sete are set in a diverging manner; and the extremity
of the joint is armed with three flat truncated spines.
The lateral appendages of the tail do not close as in the
Spherome, so as to form a convex shield, but are carried
obliquely upwards; the inner division is small and
obliquely truncate, with the entire margin thickly set
with strong bristles, and the outer division is consider-
ably larger and oval in form, but with the outer angle
subacute. The inner portion of this outer plate is par-
tially folded when at rest beneath the inner plate.

This species was taken by Montagu and Leach on the
Devonshire coast; but very sparingly. The Rev. A.
Norman dredged it in Lamlash Bay, in the Isle of Arran,
and found it under rocks at low water at Herm; and the
late Mr. W. Thompson took it in Belfast Bay, at Rock-
port, in April, and Mrs. Hyndman on Cultra shore, in
September, and Dr. Macintosh has sent it to us from
St. Andrews.

4.28 SPHHROMIDS.

ISOPODA. SPH ZROMIDA.
NORMALIA,

CYMODOCEA EMARGINATA.

Specific character. Upper surface of the posterior part of the pereion, and
especially also of the pleon, granulose, the latter sparingly clothed with short
stiff bristles, having two tubercles on the hind margin of the basal portion,
and two larger in the middle of the last segment, which has an oval lobe in
the deep apical notch.

Length, nearly half an inch.
Cymodocea emarginata. Luacu, Dictionn, Sci. Nat. xii. p. 343. Drsmarust,
Cons. Crust. p. 296. Mitne Epwarps, Crust.

ili. p. 214. Wauure, B. M. Cat. Brit. Crust.
p. 77. Pop. Hist. Brit. Crust. p. 246, pl. xiii.

5
toa

THIS species is much more granulose on the upper
surface than the preceding; the granules gradually in-
creasing in size beyond the middle of the body. The
head is very broad, and the eyes large. The basal joints
of the antennz are punctured; the terminal articuli of

CYMODOCEA EMARGINATA. 429

the flagellum of the upper pair (represented without the
two basal joints in the middle right-hand figure), are fur-
nished with flattened hairs at the tips. The foot-jaws
have the three middle joints produced into long lobes,
strongly ciliated at the tips, a portion of the cilia of the
penultimate joint being set on at an obtuse angle to the
rest. The basal portion of the tail has the middle of the
hind margin extended backwards and emarginate, with
a more or less distinct tubercle on each angle of the
emargination. The middle of the upper surface of the
terminal joint has two larger tubercles, followed by a
depressed space, terminating generally in an erect tooth
or obtuse point, the extremity of the joint armed with
three obtuse points. The lateral appendages are very
rugose and ciliated, the outer division nearly oval, but
produced on the outside, at the tip, into a point; the
inner division is narrower and curved, with the tip
pointed.

Dr. Leach took this species at Plymouth, under Mount
Edgecombe. Mr. John Cranch found specimens, less
strongly granulose, at Falmouth. We have received it
from near Glasgow, taken by Mr. Robertson. The late
Mr. W. Thompson found a specimen within the shell of
a Balanus, affixed upon a Modiola vulgaris, from Belfast
Bay.

430 SPHHROMIDA,

ISOPODA., SPHAHROMIDA,
NORMALIA,

Genus—N AiSA. (Leach).
(Nes#a—White. Nasra—M. Edwards.)

Generic character. With the sixth segment of the pereion
enlarged, and dorsally produced into a strong bidentate process.
Pleon with the upper surface irregular and setose. Uropoda
with the articulated ramus greatly elongated.

Tue dorsal surface of the body is smooth, but the
sixth segment is slightly rugose, and is armed at its hind
margin with two sharp processes extending over the tail,
which has the upper surface irregular, with two large
rounded tubercles in the middle: the outer plate of
the lateral appendages of the tail is greatly elongated,
and extends considerably backwards, whilst the inner plate
is fixed, and transversely directed inwards, nearly meeting
the corresponding division of the opposite appendage
behind the middle of the hind margin of the tail. This
peculiar structure of the tail and its appendages prevents
the animal from rolling itself into a ball in the same
manner as the Spherome, with which, in other respects,
these animals are nearly allied. The nearest approach is,
however, made to Dynamene Montagui, in which the
sixth segment of the body shows traces of the two pro-
cesses of Nesa in the bipartite tubercle of its posterior
margin.

The upper antennz are separated at the base by an
oblong protuberance; the basal joint is thick, oblong,
and rugose; the second joint small, with the apical angles
acute; the flagellum multiarticulate.

NASA BIDENTATA,

TSOPODA.
NORMALIA,

431

SPHAHROMID A.

NASA BIDENTATA,.

Specific character. Colour ashy, varied with reddish or bluish streaks ;
sixth segment of the pereion large, overhanging the base of the pleon, which

has two oval rugose tubercles in the middle.

Length, about one-third of an inch, ‘‘ Six lines’—Leach.

Oniscus bidentatus, ApAms, Trans. Linn. Soe. vol. v. p. 8, t. 2, £. 3, 4.

Nees bidentata. Lracu, Dict. Sci. Nat. xii. p. 341.

Edinb. Ene. vil.

p. 405. Trans. Linn. Soe. xi. p. 367. Suppl. Enc,
Brit. i. p. 427. SamovEnie, Ent. Compend, p. 108.

Mitnt Epwarps, Crust. iii.
Cons. Crust. p. 295, t. 47, £. 2.

p. 217. Dursmarxsr,
Wuits, B. M. Cat.

Brit. Crust. p. 78. Pop. Hist. Brit. Crust. p. 247,
pl. xiv. f. 1. Gossz, Man, Mar. Zool. 1, 185, fig. 237.

Tuls species is at once distinguished from all the other
British species of the family by the structure of the
large sixth segment of the body, armed on its hind
margin in the middle with two long divergent, slightly
incurved rugose teeth, which completely conceal the

432 SPH EROMIDA.

seventh segment of the body and the basal portion of the
tail. The body is rather narrow, and smooth on the
upper side of the anterior portion. The tail is very
rugosely granulated, and furnished in the middle of its
upper surface with two erect tubercles. The outer
division of the lateral appendages extends considerably
beyond the extremity of the body; it is oblong, and
slightly pointed at its extremity; its surface rugose, and
its edges strongly bristly.

Taken on the south-west coast of England* by
Montagu and Leach; also at Polperro, Cornwall, by Mr.
J. Couch; at Carrickfergus, Lough Shinny, Dublin, by
Dr. Kinahan; Cork, Professor J. R. Greene; Roundstone,
Mr. W. M‘Calla; coast of Ireland, Professor Huxley ;
also Vagon Bay, Guernsey, by the Rev. Alfred Norman.
We have found it common amongst weed between tides
on the rocky shores of South Wales, South Devon, and
Cornwall; and believe it may be met with in similar
localities all round our coasts. It is generally associated
with Dynamene Montagui, of which we think it may
possibly turn out to be the male.

* Dr. Leach, by a lapsus calami, says :—‘‘ Habite les rochers de la partie
occidentale de I’ Amerique.”

CAMPECOPEA. 433

ISOPODA. SPHH@ROMIDA,
NORMALIA.

Genus—CAMPECOPEA. (Leach.)

Generic character. Oval and very convex ; sixth segment of
body entire, or armed with a single long tooth in the middle
of its hind margin; articulated ramus of the uropoda forming
a long exserted curved plate: interior division obsolete, or very
minute.

THE species of this genus are the smallest in the pre-
sent family. They have the body very much arched, and
capable of doubling itself closely up, but not into a perfect
ball. The sixth segment is larger than the seventh (and
in some individuals, which we regard as males, it is very
much enlarged), and produced in the middle of its
posterior margin into a long tooth, which extends back-
wards over the tail, but varying in length in individuals
according, probably, to the period of their growth. This
remarkable tooth, not having been represented by
Montagu, has been overlooked in the descriptions of the
genus and its species by Desmarest and other later
writers, although originally mentioned by Leach in the
«Dictionnaire des Sciences Naturelles.” The seventh
segment of the body is very short, as is also the basal
division of the tail, whereas the terminal division of the
latter is of large size, rounded behind, entire, and armed
at each side with the greatly elongated, curved, lateral
appendages, the outer division of which is setose, and
the inner appears to be obsolete, or very minute. The
foot-jaws have the intermediate joints produced into
rounded lobes at the inner apical angles. The antennx
are cylindrical, with the basal joints thickened.

VOL. Il. FF

434

ISOPODA.
NORMALIA.

SPHHROMID&.

SPHEROMID,

Specific character.

CAMPECOPEA HIRSUTA.

Hirsute; sixth segment having the middle of the pos-

terior margin, armed with a long straight tooth, extending backwards. Colour
brown ; pleon marked with pale blue dots.

Length, one-eighth of an inch.

Oniscus hirsutus.

Campecopea hirsuta.

Montagu, Trans. Linn. Soc. vii. p. 71, t. 6, f. 8.
Leacu, Edinb. Enc. vii. p. 405. ‘Trans, Linn. Soc.

xl. p, 367. Dictionn. Sci. Nat. xii. p. 341. Suppl.
Ene. Brit. i. 427. Samovrenie, Ent. Compend.
p. 107. Drsmanzst, Cons. Crust. p. 294, t. 47, f£. 1.
GuRIN-MENEVILLE, Icon. R. An. Crust. t. 30, f. 3.
MinnE Epwarps, Crust. iii. p. 220. Wuurts, B. M.
Cat. Brit. Crust. p. 78. Pop. Hist. Brit. Crust.
p. 248, pl. xiv. f. 2. Gossz, Man. Mar. Zool. i.
fig. 238.

Tus curious little species has the body oval, very con-
vex, and very much arched, the upper surface being very
hirsute; the tail large, semicircular, very convex, and

CAMPECOPEA HIRSUTA. - 435

armed on each side with a long curved and serrated oar, or
fin-like outer division of the posterior lateral appendages,
of which the inner is apparently obsolete. The sixth
segment of the body is armed with a long posteriorly
deflexed spine. The seventh segment of the body is very
short ; the legs are terminated by a strong curved finger ;
the extremity of the preceding joint being also produced
into a point, so as to give the appearance of double
claws to the leg. The outer maxille are of the usual
form, and the foot-jaws have a large apical lobe, whilst
the intermediate joints have their inner angles produced
into rounded setose lobes. In the middle figure (e?) we
have represented a structure which presented itself to us
on dissecting the mouth, which we consider to be the
inner maxilla, although differing from the ordinary form
of those organs, which generally consist of three equal-
sized membranous plates of identical form and structure,
and with a similar ciliation at the tips. In figure P is
represented the underside of the tail, with the omission
of the delicate tail-feet or breathing-scales. The terminal
segment of the tail is slightly carinated at its extremity.

The species was found by Montagu on the coast of
Devonshire. We have also taken it in some profusion
at Torquay and Polperro, amongst the small dry fuci
that exist on the surface of the rocks within the reach of
the spray of the sea, but where the sun appears to drain
off all moisture.

436 , SPH EROMIDA.

ISOPODA. SPHAROMID &.
NORMALIA.

CAMPECOPEA CRANCHII.

Specific character. Slightly setose ; sixth segment of the pereion simple,
unarmed ; terminal segment of the pleon entire, convex, not carinated, at its
hinder part.

Length, one-tenth of an inch.

Campecopea Cranchiit. Lnacn, Dictionn. Sci. Nat. xii. p. 341. DesmArust,
Cons. Crust. p. 295. Muitne Epwarps, Crust. iil.
p. 220. Wuitr, B. M. Cat. Brit. Crust. p. 78.
Pop. Hist. Brit. Crust. p. 248.

TuIs species is smaller than C. hirsuta; it is also much
less hirsute, and the sixth segment of the body, although
larger than the preceding and following segments, is
destitute of the elongated spine which existsin C. hirsuta.
The antennz are cylindrical; the upper pair are inserted
rather widely apart, with the first and second joints
thickened, the second being of the ordinary rounded
form, and not having the anterior angles acute. The
inner maxille are composed of three delicate overlapping

CAMPECOPEA CRANCHII. 437

plates of equal size and structure, which is the ordinary
type of these organs. The legs are terminated by two
strong hooks. The tail has the last joint entire and
convex, without any appearance of carina.

Taken at Falmouth by Mr. Cranch. We have found
this species mingled plentifully with the preceding, and
believe it will ultimately prove to be only the female
form of C. hirsuta.

We take this opportunity, at the close of the de-
scriptions of the water-breathing Isopoda, to refer to
Professor Schiodte’s recent elaborate memoir on the
structure of the mouth of these animals, with especial
reference to the parasitic suctorial species composing the
family Cymothoide (of which we possess no British repre-
sentative), published in the ** Naturh. Tidsskrift,” ser. iii.,
vol. iv., and of which a careful translation has just been
published in the ‘Annals of Natural History” for
January, 1868.

438 ERO-SPIRANTIA.

Division—AZRO-SPIRANTIA.

WE have now arrived at that division of the order
Isopoda which comprises the species that differ from
the great majority of those animals, and indeed (with the
exception of the land-crabs) from the remainder of the
class Crustacea, in the manner in which respiration is
effected; these animals residing, not in water, but in
damp situations, and breathing air, which, however, it is
necessary should be saturated with moisture, as has been
fully proved by a careful series of experiments published
by Messrs. Duvernoy and Lereboullet in the ‘ Annales
des Sciences Naturelles,’ 2nd series, Zool., tom. 15,
p- 205. The specialized structures by which this is
effected will be noticed below. We must here, however,
refer to the exceedingly interesting genus, Tylos of
Latreille, founded upon an Egyptian species elaborately
illustrated by Savigny in the great work on Egypt
(Crust. pl. 13, f. 1), in which respiration is effected in a
double manner, namely, by the action of the water or
moistened air on the external surface of the respiratory
branchial plates or false legs on the underside of the
tail, in the same manner as in the Idotew and other
normal Isopods, and by the inspiration of air by means
of certain spiracular orifices on several of the basal pairs
of these same appendages. We have searched in other
genera for these peculiar organs, but without hitherto
being successful,

The division, which corresponds with the family
Cloportides of Latreille and Milne Edwards, comprises
the single

ONISCIDA. 439

Family—ONISCID.

THESE animals are further distinguished by having the
anterior pair of antennz almost rudimental, so that they
appear to possess only one pair of these organs. ‘The
tail is composed of six distinct segments; but the ter-
minal joint, instead of being of large size, and formed
into a shield-like plate, is here small, and sometimes
almost rudimental. The legs are only formed for walking,
and the mandibles are destitute of the lateral articulated
appendage resembling a three-jointed palpus.

The species for the most part are of comparatively
small size, and are indiscriminately known under the
common names of wood-lice, hog-lice, carpenters, &c.
With the exception of the species of Ligia (which com-
prises the largest individuals of the family, and which are
found in rocky places on the shores of the ocean in
various parts of the world), the Oniscide are inland
creatures. Of fourteen species described by Professor
Kinahan in his memoir on this family, read at the British
Association in 1857, and published in the ‘* Dublin
Natural History Review,” vol. iv., he states that all,
except two (one a marine species), had been found by
him in a garden not sixty yards square, and nearly all
in abundance.

Several of the species which inhabit caves and sub-
terranean situations are destitute of eyes. This is the
case with T%tanethes albus, described and admirably illus-
trated by Schiodte in his memoir on the cave-animals
—“ Specimen Faunz Subterranee,”—published in the
“ Transactions of the Royal Society of Denmark,” 5th

440) ONISCIDA.

series, vol. ii., and which is evidently identical with
Koch’s Pherusa alba (‘ Herrich Schaffer, Contin. of
Panzer,” Fasc., 180, pl. 24). Another curious blind
species, closely allied to Platyarthrus, has been described
by Schobl, under the name of Typhloniscus Steinii, in the
“Proceedings of the Imperial Academy of Vienna for
1860.” It lives in ants’ nests. The memoir is illustrated
by ten elaborate plates.

These animals have recently attracted considerable
attention amongst foreign carcinologists, since, in addition
to the special memoirs of Brandt (‘‘ Conspectus Mono-
graphiz Crustaceorum Oniscodorum,” in Bull. Soc. Nat.
Moscow, 1853); Lereboullet (‘* Sur les Crustaces de la
Famille des Cloportides qui habitent les Environs de
Strasbourg,” in the ‘‘ Contes Rendus,” 1845, t. 20, No. 6,
and in the ‘‘ Memoirs of the Nat. Hist. Society of Stras-
bourg” for 1853); and Professor Kinahan (of whose
memoir, entitled ‘‘ Analysis of certain allied Genera of
Terrestrial Isopoda,” in the ‘‘ Natural History Review,”
vol. iv., 1857, and supplement in ditto, 1858 and 1859, we
have greatly availed ourselves); there have been pub-
lished several other memoirs, which have been greatly
overlooked, namely, Burgersdijk’s ‘‘ Specimen Acade-
micum inaugurale continens Annotationes de quibusdam
Crustaceis indigenis,’ S8vo, Lugduni Batav. 1852;
Schnitzler’s Memoir “de Oniscineis agri Bonnensis,”
8vo, Coloniz, 1853; Stein’s ‘Catalogue of the Crus-
tacea and Myriapoda of the Grisons,” published in the
** Annual Report of the Natural History Society of the
Grisons” for 1855, in which fifteen species of the family
are described; and Johnsson’s “Synoptisk Framstallning
af Sveriges Oniscider, Upsala,” 1858. In Koch’s “ Con-
tinuation of Panzer’s Deutchslands Insecten’’ (pub-
lished also separately), not fewer than sixty-one supposed

ONISCIDA. 441

species belonging to this family are figured; but this
writer carried the creation of species, not only of these
animals, but also of the Acaride, to an undesirable ex-
tent; every slight variation of colour being regarded as
of specific value. It is very probable that when greater
attention shall have been devoted to these creatures in
this country, other species will have to be added to our
native lists than are described in the following pages.

This family is divisible into two sub-families—

1. The Ligiine, having the flagellum of the outer
antenne multiarticulate, and the terminal pair of caudal
appendages with the basal joints greatly elongated, and
terminated by two long and slender subequal rami;
consisting of the genera Ligia (sub-marine species), and
Ligidium, composed of a single European species, found
in damp moss.

2. The Oniscing, having the flagellum of the outer
antenne not multiarticulate, and the terminal pair of
pleopoda with the basal joints very short, and furnished
with two short flattened unequal rami, of which the
inner is sometimes nearly obsolete, comprising the

remainder of the species.

SANDGATE.

442 ONISCIDA,

ISOPODA, ONISCID4:.
NORMALIA.

Genus—LIGIA. (Fabricius.)

Generic character. External antenne long, with a multi-
articulate flagellum. Terminal pair of uropoda with the basal
portion exserted backwards, truncated at its extremity, to
which are affixed a pair of elongated cylindrical rami.

Tue head is small, its anterior margin forming a con-
tinuous arched line with the sides of the first segment of
the body.

*¢ When the head is looked down on from the front, we
remark anteriorly, just beneath, but not attaining to the
frontal line of the head, a broad plate extending over
the entire forehead, and divided transversely by a raised
ridge ; its superior margin is also marked by a raised
ridge. This superior ridge passes off on each side
beneath the eyes, forming at least a third of the inferior
border of the orbit. The external angle of the orbit,
however, is formed not by this, but by the cephalic ring
continued forward from behind, and terminating as a
rounded knob just above the external antenne ; these
arise in the angle between the inferior border of the
frontal plate and the projecting lobes. The inferior
border of the frontal plate is formed of two curves,
convex upwards, one over the origin of each external
antenna; the angle of their junction is truncate, sepa-
rated by a short transverse suture from a small, narrow,
somewhat quadrilateral plate, which bears the internal
antenne, and is probably the remains of the second or
internal antennary ring; the frontal plate itself repre-
senting the external antennary or third ring of the typical
crustacean. Beneath is a broad, well-marked plate, the
epistome.”—Kinahan, op. cit. p. 264,

LIGIA. 443

The outer antenne are of considerable length, con-
sisting of a strong five-jointed peduncle, of which the
joints gradually increase in length, followed by a multi-
articulate flagellum, which, in our only British species,
contains thirteen or fourteen articuli, the last being ex-
tremely minute; but in some of the exotic species as
many as thirty. The inner antenne are very minute,
flattened, and three-jointed. They are inserted close
together, just above the clypeus, and are not longer than
the basal joint of the outer pair.

The body is oval and moderately convex, with the
seven segments well developed, the lateral portions, con-
sisting of the coxe, or first joint of the legs soldered to
the segments, being indicated by slightly impressed lines,
nearly parallel with the lateral margins, and being nearly
equally developed in all the segments. ‘The tail consists
of six segments, of which the two anterior are distinct
on the middle of the back, but with the sides shortened
and concealed by the posterior direction of the lateral
extremity of the preceding segment of the body. The
third and two following segments of the tail are free, and
have their posterior angles acute; whilst the terminal
segment has the posterior margin rounded, and on each
side the posterior angle is produced to a tooth. The ter-
minal pair of appendages are posteriorly exserted, and
are more or less elongated in various species. The basal
joint is truncated at its extremity, and furnished with a
pair of elongated cylindrical rami of nearly equal length
and size, the inner one terminated by a solitary strong
hair.

The species are extremely active. They are very com-
mon on rocks just above high-water mark, hiding them-
selves in crevices of the rock and beneath stones with
ereat agility.

444. ONISCIDA.

ISOPODA. ONISCID,
NORMALIA,

LIGIA OCEANICA.

Specific character. Somewhat depressed, oval, cephalon transverse,
covered with smooth granulations. External antenne with the flagellum
fourteen-jointed, nearly glabrous. Last segment of pleon rounded posteriorly,
with the lateral angles projected on each side. Terminal uropoda with the
peduncle nearly as long as the last segment of the pleon.

Length, about one inch.

Oniscus oceanicus, Linn. Syst. Nat. ii, p. 1061. Punnanr, Brit.
Zool. (Kdit. 1777), iv. t. 18, f. 4.
Ligia oceanica. Fasricius, Ent. Syst. Suppl. p. 301. Latrernie,

Hist. Nat. Crust. et Ins. vii. p. 31. Lracu,
Trans. Linn. Soc. xi. p. 374. Edinb. Enc.
vii. p. 406. Enc. Brit. Suppl. i. p. 428.
SAMOUELLE, Ent. Compend. p. 111. Drs-
MAREST, Cons. Crust. p. 317, t. 49, f. 3-4.
Rovx, Crust. Mediterr. t. 13, f. 8. Minne
Epwarps, Crust. iii. p. 155. Branpt, Bull.
Mose. vi. p. 172. Wauutr, B. M. Cat. Brit.
Crust. p. 71. Pop. Hist. Brit. Crust. p. 233,

LIGIA OCEANICA. 445

pl. xiii. f. 1, Kinauan, Nat. Hist. Rev. iv.
279, pl. xx. f. 7-10. Gossr, Man. Mar.
Zool. i. fig, 241.

Oniscus aquaticus. Bastzr, Opuse. Subs. ii. t. 18, f. 4.
(Var.) Ligia scopulorum. Leacu, Edinb. Ene. vii. p. 406. Linn. Trans.
xi. p. 374.

Tus is the largest British species in the family, from
the rest of which it also differs by being found under
stones, &c., in damp places on the shores of the ocean. It
has the upper surface of the body slightly rugose, being
covered with depressed granulations. The first segment
of the body has a deep transverse impression immediately
behind the head. The segments of the body have the
lateral margins thickened, curved, and terminating behind
in a rather sharp angle. The outer antenne are about
two-thirds of the length of the entire animal; they are
robust, with the fourth and fifth joints much larger than
all the rest. The flagellum differs in the number of
articuli, probably on account of the difference in the
ages of the different individuals. The upper lip is entire,
and rounded at its free anterior margin. The lower lip,
on the contrary, is very deeply incised in the middle,
with the interior angles of the incision setose. The
mandibles are strong, armed with two compound teeth,
and with a strong incurved molar plate. In fig. d’ the
mandible is seen laterally, the inner tooth and plate not
being visible from being on the same plane as the upper
tooth. The inner maxille are formed of two terminal
lobes, of which the outer is terminated by several strong
straight bristles, whilst the inner is shorter, and armed
with three deflexed setose bristles. The outer maxille
have the two terminal divisions formed into two short
joints, with two or three strong short bristles on the out-
side of the penultimate joint. The preceding portion
has its inner apical angle produced into a setose fleshy
lobe.

446 ONISCIDA.

The terminal segment of the tail is longer, but nar-
rower than the preceding. Its posterior margin is regu-
larly rounded, whilst on each side the lateral posterior
angle is produced into a strong tooth. The branchial
apparatus consists of the five anterior pairs of the deli-
cate membranous plates on the underside of the tail,
through the centre of which a large artery passes to
about two-thirds its length, sending off numerous
branches that break up into a minute vascular network
that spreads itself out over the entire surface. Of these
plates the first pair is furnished, in the male, with a pair
of minute linear styles at the inner angles. The second
pair in the same sex is armed at its inner extremity with
two long and nearly straight appendages, extending to
the middle of the fifth pair. The terminal pair of these
organs is formed into elongated appendages at the ex-
tremity of the body, of which the basal portion or
peduncle is longitudinally elevated in the centre, but
laterally depressed, oblong, with the posterior extremity
narrowing. It articulates in a distinct notch of the pos-
terior margin of the segment. The extremity of this basal
portion is truncate, with the outer angle acute, and with
the lateral lobe obsolete. It bears two filiform cylin-
drical appendages, which under a strong lens are seen to
be furnished with minute regularly distant hairs. The
inner is rather longer than the outer, and furnished at its
extremity with a minute but strong hair.

The eggs and young are borne by the female beneath
the body ; the latter have only six segments of the body,
and six pairs of legs, the seventh segment being rudi-
mental, when they first quit the ovary.

The general colour is dull light green in the young
male, with white spots.

The male is much larger than the female, and is gene-
rally of a paler and less varied colour.

LIGIA OCHANICA. 447

The male organs consist of a pair of small styliform
processes, centrally attached to the anterior or first seg-
ment of the pleon. ‘These are connected by slender
ductus ejaculatorti to a vas deferens, that suddenly enlarges
and gradually diminishes to the extremity, where it
divides into three testes, which enlarge, and gradually
thin out with extreme delicacy. The external surface
of the ductus ejaculatorii is marked by many small cells
of black pigment.

This species is common on all our coasts, running
with agility, and folding in the extremities so as to feign
death. It indiscriminately feeds on decaying animal and
vegetable substances, along tide-marks and rocks. It is
seldom found under water, and may be observed running
over the sand in full sunshine.

We have occasionally found them dead, yet standing
on the rock as if they were alive and well. On exa-
mination, we have found that the branchial plates had
been destroyed, probably by some insect, but of this
fact we have no direct evidence.

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Microscopical representation of the texture of the dorsal
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4.48 ONISCID A.

ISOPODA. ONISCID 4.
NORMALIA,

Genus—PHILOSCIA. (Latreille.)
ZILIA. (Koch.)

Generic character. Ovate, sub-depressed. Cephalon rounded,
not lobed. Inner antenne minute, conical. Outer antennee
with cylindric joints, eight-jointed. Coxe of sixth segment
of pleon obsolete; first to fifth, narrow, linear. Uropoda
entirely exserted; basal portion quadrilateral, transverse.
Rami elongate, pointed at tip; outer terminating in a bundle
of sets; inner more slender, and extending beyond the
middle of the outer ramus.

Ir is a curious circumstance that the animals of this
genus, common as they are, and well described by
Latreille and Zaddach, should have been unknown to
Brandt, Lereboullet, and Milne Edwards, who have
affirmed that the genus ought to be reunited to Oniscus,
whereas it is in fact more nearly allied in several respects
to Ligia. The typical species appears to have been
figured by Koch under the name of Ligia melanocephala,
which in his generic table he subsequently altered into
the generic name of Zia, giving, however, fifteen joints
to the antennee, the flagellum being represented as com-
posed of ten articulations.

The species are glossy, with the body flattened, and
the head destitute of lateral or frontal lobes. ‘* The
inferior border of the frontal ring of the head is nearly
straight across; the transverse suture well marked,
nearly on a level with the superior margin of the ex-
ternal antenne, its superior margin curved, raised, and
passing slightly beyond the frontal line of the cephalic

PHILOSCIA. 449

segment, shutting out the orbit from the insertion of the
external antennz, and a deep sulcus separating it from
the external angle of the orbit; the third ring being
thus transverse and narrow. The second ring is nearly
as deep as the third, and well marked; the epistomal
narrow, and formed of two triangles placed apex to apex.
The orbits are open below and behind.”—Kinahan.

The inner antennez are very small, conical, and three-
jointed. The outer antennz are cylindrical and eight-
jointed, the three terminal joints forming the flagellum, ©
which is tipped by a small short articulus. The legs
have the lower margin of the intermediate joints armed
with bristles; they are terminated by a very minute
hook or finger, which is slightly bifid at its tip.

The two anterior segments of the tail are not produced
into exserted lateral angles, as is the case with the three
following. ‘They are, however, narrower than the ter-
minal segments of the body. The terminal segment is
triangular, with the sides slightly emarginate for the
insertion of the caudal appendages, which are elongated,
and have the basal portion uncovered; the inner ramus
of each is more than half the length of the outer.

The species are found in dry moss, at the roots of
trees, and under leaves and stones. ‘They run with great
quickness, and do not hide away from the light. They
do not attempt to roll themselves up into a ball, but
feign death when alarmed.

VOL. II. GG

450 ONISCIDA.

ISOPODA. ONISCIDA,
NORMALIA.

PHILOSCIA MUSCORUM.

Specific character. Smooth, shining; front of the cephalon slightly
arched in the middle. Terminal segment of the pleon broadly triangular,
apex acuminated, sides straight. Uropoda with the outer division falciform ;
the inner lobe scarcely more than half the length of the latter.

Length, one-fourth to one-third of an inch.

Oniscus muscorun. Scopour, Entom. Carniol, p. 1145. Cuvier, in Journ.
d’Hist. Nat. i. t. 26, f. 6, 7. Cogqumspert, Illust.
Iconog. t. 6, f. 12.

Philoscia muscorum. Latremnix, Hist. Crust. et Ins. vii. p. 43. Gen.
Crust. et Ins. i. p. 69. Leacu, Trans. Linn. Soc.
xi. p. 375. Edin. Ene. vii. p. 406. Suppl. Ene.
Brit. i.p.428. Samovrniy, Ent. Compend. p. 111.
Kinanan, Nat. Hist. Rev. v. 4, 1857, p. 280,
pl. xx. figs. 1-6; v. 5, 1858, pp. 194, 195, pl. xxi.
f. 4. Wuuits, B. M. Cat. Brit. Crust. p. 72. Pop.
Hist. Brit. Crust. p. 235. (Not the P. muscorwm
of Lereboullet, which is an Oniscus.)

Oniscus sylvestris. Fasricius, Ent. Syst. ii. p. 397.

Ligia melanocephala, Kocou, in Herrick-Schaffer Contin. of Panzer Ins.
Deutsch]. 162, 18; ibid. Deutschl. Crust. 22, 18.

Zia melanocephala. Ibid. sub. Ins. D. 180, 1, and D. Crust. 40, 1.

PHILOSCIA MUSCORUM. 451

Tuts species is smooth and shining, generally of a
fulvous colour, with dark black patches and white spots.
The head is transversely elliptical and arched in front,
being destitute of any lateral or median lobe. The
internal antenne are small and inconspicuous; the outer
antenne are cylindrical and setose. The tail is much
narrower than the terminal segments of the body, with
the last ring broadly triangular, its apex being acute,
and its terminal appendages having the outer division
elongate-trigonate, spinous along its lateral margins; the
inner lobe nearly as long as the latter.

The species runs with great rapidity, and seeks the
sunshine. Jt is widely distributed, and very common.
It prefers dry rather than damp situations, under leaves,
stones, and moss; also near the sea-shore. It is found
abundantly throughout the southern part of England.
Professor Bell found it under stones at Cheriton, and
observes in his manuscript notes—“ I found it of every
shade of colour, from rich black to reddish brown and
light green. It is more active than any other species,
and the crust is more tender, and easily injured.” Add-
ing—“ I believe colour to be absolutely valueless as a
specific character in the whole of the Oniscide.”

Dublin, Wicklow, Meath, Wexford, Cork, Waterford,

and Tyrone, have been recorded as Ivish localities.

Gem,

4.52 ONISCIDA.

ISOPODA. ONISCIDA,
NORMALT4.

PHILOSCIA COUCHII.

Specific character. Smooth and glossy. Front of the cephalon nearly
straight. Terminal segment of the pleon linear-triangular, with the apex
obtusely truncate, armed with bristles, the sides slightly excavated. Outer
ramus of the uropoda subulate-falciform ; the inner not more than one-fourth
of the length of the former.

Length, one-fourth of an inch.

Philoscia Couchti. Kinanan, Nat. Hist. Rev. vol. v. 1858, p. 195, pl. 23,
fig. 4,

THis species was first described by the late Professor
Kinahan, who gave the following characters of it :—“ Body
smooth, elliptical. Head somewhat rounded, nearly
straight across the front; beneath the orbits is a small
lobe arising from superior margin of the antennal ring.*
Internal antennze inconspicuous; external antenne hairy.
Tige (flagellum) long and narrow. Abdomen (tail) nar-
rower than the cephalo-thorax (body). Telson (last seg-
ment) narrow, linearly triangular; apex rounded and

* Tn the new species the frontal border of the carapace (cephalon) is
carried well forward, and passes down to the antenns, the superior antennal
ring having its margin produced into a minute lobe beneath the orbit. This

species fully proves the judiciousness of the separation of Philoscia from
Oniscus.”

PHILOSCIA COUCHII. 453

fringed with stiff bristles, sides excavated. Posterior
pleopods (uropoda) with the ischium (outer ramus) elon-
gate, falciform, subulate. Accessory appendage (inner
ramus) scarcely one-fourth the length of the ischium,
In other respects as in Philoscia muscorum.” The colour
is lead-grey, and uniform to the naked eye.

The species runs with agility, but does not roll itself
up into a ball. It was discovered at Talland Cove, near
Polperro, from whence we were returning accompanied
by Professor Kinahan, who gives this account of its dis-
covery :—‘‘ In returning home we took the cliff road,
and at Talland Cove spent a few moments examining the
supra-littoral zone (the tide being nearly full in). Here,
as might be expected, Ligia oceanica, Porcellio scaber,
Philoscia muscorum, and Orchestia littorea, were abundant ;
but I was much pleased by also meeting with a Philoscia
new to me, and also undescribed in the books. ‘This I
have named Philoscia Couchii, in memorial of one of the
pioneers in the study of the zoological geography of
England, and of a few pleasant hours spent in his com-
pany. The species appeared abundant, and the following
description of the spot where it occurred may probably
aid others in finding it :—Having descended the hill from
Polperro, you cross the stream which drains an extensive
osier marsh. The road then turns up a narrow ferny
lane into a very heavy hill. Instead of turning up this
lane, keep straight on from the bridge, and a few yards
brings you up at the foot of the cliff. Here, amongst
the loose stones and sea-weed carried up by the high
tides into the clefts of the slate rocks, in company with
the other Oniscoids, and many Myriapods, Philoscia Couchii
will be seen hiding among the shingle, and easily distin-
guishable from P. muscorwm, which also occurs, by its
uniform colour.”

454 ONISCIDA.

ISOPODA. ONISCID.
NORMALIA.

Genus—PHILOUGRIA. (Kinahan.)
ITEA.* (Koch.)

Generic character. Ovate, sub-depressed. Cephalon without
frontal or lateral lobes. Outer antenne nine or ten-jointed,
with the second joint cylindrical ; terminal joints subulated.
Coxee of first and sixth rings of pleon obsolete. Uropoda
entirely exserted; basal portion trigonate. Outer ramus
elongate, pointed, and exserted obliquely. Inner narrow,
extending beyond the middle of outer, pointed.

THIs genus was first proposed by Zaddach, and subse-
quently adopted by Koch under the name of Jtea—a
name employed by Linnzus for a well-known genus of
plants. Its description also was not sufficiently precise ;
whence Professor Kinahan was at first induced to con-
sider the native species as undescribed, both generically
and specifically. For both these reasons we consider
ourselves warranted in adopting the generic name pro-
posed by the lamented Ivish naturalist.

The species are of comparatively small size, with the
body smooth and shining. The limbs are armed with
strong spines, generally arising from small conical
tubercles. The structure of the front part of the head
is nearly similar to that of Philoscia, but the lateral
ridges around the insertion of the external antenne are
somewhat more strongly marked. The outer antenne
are entirely exposed at the base. The five basal joints
constituting the peduncle are robust, spined, and gra-

* Nom. Gen. Plantarum.—Linn.

PHILOUGRIA. 455

dually elongated to the fifth joint. The flagellum con-
sists of four or five slender joints, generally terminated
in a small pencil of sete.

The body is elongate-ovate, and the tail is considerably
narrower than the former, with the lateral-posterior
angles of the second and three following segments pro-
minent; and the terminal segment is broad and truncate
at its extremity, with the terminal caudal appendages
(uropoda) of considerable size, and partially covered,
with the basal portion, somewhat triangular, affixed in a
notch in the underside of the posterior margin of the
terminal segment. The outer ramus is long and acumi-
nated, terminating in a seta; the inner slender and
acuminated, more than half the length of the outer.

The species are very active, and reside in damp situa-
tions, thus agreeing with Philoscia.

4.56 ONISCIDA.

TSOPODA. ONISCIDA.
NORMALIA.

PHILOUGRIA RIPARIA.

Specific character. Hlliptical, smooth and glossy. Inner antenne very
minute and inconspicuous. Outer antenne nine-jointed. Terminal segment
of the pleon deeply emarginate on each side, truncate, triangular, with the
extremity deeply emarginate.

Length, three-twentieths of an inch.

Itea riparia. Kocu, in Cont. Panz. Ins. Deutsch]. 162, 17; and
Deutschl. Crust. 22, 17.

Philougria riparia. Krnauan, Nat. Hist. Rev. vol. v. 1858, pp. 197, 198,
pl. 23, fig. 1.

Ttea levis (2). ZappAcH, Syn. Crust. Pruss. p. 16.

Philougria celer. Kinanan, Nat. Hist. Rev. vol. iv. 1857, p. 281,
pl. 22, figs. 1-4.

Tue colour of this small species is uniformly claret-
brown, appearing under a lens to be beautifully marbled
with white. It is distinguished by its elliptical outline,
and by the terminal segment of the tail being deeply

PHILOUGRIA RIPARIA. 457

excavated over the insertion of the posterior pleopoda
or terminal appendages ; its middle portion is produced
backwards, truncately triangular, and deeply emarginate
at the tip. Under a lens the skin is found to be marked
with minute semicircular incised lines, giving the appear-
ance of a series of scales, as seen at Fig. n’. The outer
antennze appear to us to consist of only nine joints, the
flagellum consisting of only the four terminal articula-
tions.

This species appears to be widely dispersed throughout
Ingland and Ireland, although rare in the southern
counties of the former. It has been taken near Dublin,
Wexford, Cork, and Kerry by Dr. Percival Wright, |
and at Tyrone, Waterford, Portlaw, Kilkenny, and
Wicklow (Prof. Kinahan). In Epping Forest and
Chiselhurst, Kent; also at Plymouth; Polperro (in the
gardens of the inn, not uncommon); Looe abundantly,
among sticks by the river side. It is found in very
moist places amongst all kinds of decaying matter, also
amongst moist dead leaves, amongst wet ashes, and in
moss, at the roots of trees. It runs with agility, buries
itself deep in the ground, and generally congregates in
numbers. It is very impatient of dryness, soon dying
on exposure to air (Kinahan). It feigns death when
disturbed, but does not attempt to roll itself in the least.
Professor Kinahan found it with ova and young from
February to November.

458 ONISCIDA.

ISOPODA. ONISCID &.
NORMALIA.

PHILOUGRIA VIVIDA.

Specific character. Oval, smooth, glossy. Terminal segment of the pleon
triangular, truncate, the extremity nearly straight, without any emargination ;
above, deeply sulcated. Outer antennz ten-jointed. Colour brown, marked
with small buff-white dots.

Length, five-twentieths of an inch.

Ttea vivida. Kocu, in Cont. Panzer Deutsch]. Ins. 180, 4;
and Deutsch]. Crust. 40, 4.
Philougria vivida. Krinauan, Nat. Hist. Rev. vol. v. 1858, pp. 197,

198, pl. 23, fig. 2.
Junior (2) Itea nana (?). Koon, Opp. cit. 180, 5, and 40, 5.

Tue general colour of this species is claret-brown,
marbled with white when seen under a lens. It is of an
oval form, smooth and shining, with the surface of the
skin marked, in addition to the small fine curved scale-
like appearance of the preceding species, with small scat-
tered impressed dots or pits, as shown in Fig. H’. The

7

PHILOUGRIA VIVIDA. 4.59

second joint of the outer antenne is produced into an
angle at its inner extremity, and the flagellum consists of
five slender articuli. These organs are destitute of the
spines which distinguish the other species. The terminal
segment of the tail is triangular, truncate at the ex-
tremity, very nearly straight and deeply furrowed above,
but not emarginate. The caudal appendages are trigono-
subulate.

Taken not uncommonly under stones and moss on hills
at Portlaw, in the county of Waterford, by Dr. Kinahan,
in great abundance in March, 1858, even in the midst of
snow. It runs with great agility, and does not bury
itself deep in the earth like Ph. riparia.

460 ONISCIDA.

ISOPODA,. ONISCIDA,
NORMALTIA.

PHILOUGRIA ROSEA.

Specific character. Ovate, scabrous, covered with small tubercles. Eyes
small, Inner antenne conspicuous. Outer antennze with the flagellum
slender, with apparently only four articuli, which are very difficult to detect
except under a strong lens; tipped with a pencil of hairs. Terminal segment
of the pleon with the extremity truncated, straight. Colour reddish, with
whitish spots and dorsal line.

Length, three-twentieths of an inch.

Jtea rosea. Kocu, in Contin. Panzer Deutsch]. Ins. 162, 16; and
Deutschl. Crust. 22, 16.

Philougria rosea. Kinauan, Nat. Hist. Rev. vol. v. 1858, pp. 197, 199,
pl. 23, fig. 3.

Tuis species is distinguished by its colour, which is
of a clear minium-rose, with white dots, and with a
white stripe down the median line, or (in specimens found
in dark places) of a dead white, having a dark median
line. The upper surface, except that of the posterior

PHILOUGRIA ROSBEA. 461

segments of the tail, is tuberculated, each tubercle
emitting a minute seta at its top. The eyes are small,
black, and conspicuous. The inner antennz are very
conspicuous, extending beyond the front, and consisting
of three joints with the tip setose; the outer antenne
are composed of five joints, besides the slender flagellum,
which consists of four articuli, terminated by a long
brush of hairs; the basal joints of these antenna are
armed with strong bristles arising from small triangular
lobes. The lateral angles of the head beneath the orbits
of the eyes are strongly marked. ‘The terminal segment
of the body is flat above, with the extremity truncate,
and armed with several strong bristles.

We believe that this species has only hitherto been
found in Mr. C. Spence Bate’s courtyard and cellar, and
that of neighbouring houses, at Plymouth, where it is
tolerably abundant. Its habits agree with those of the
rest of the genus, but it appears to frequent more humid
haunts. It feigns death, but does not attempt to roll
itself up, and is not quite so active as the other species.

4.62 ONISCIDA.

ISOPODA. ONISCID 4.
NORMALIA.

Genus—PLATYARTHRUS. (Brandt.)

Generic character. Flattened, broadly ovate, scabrous.
Cephalon transverse. Lateral and frontal lobes strongly
developed, arising from the anterior margin. Outer antennee
apparently six-jointed ; second joint small; third short, nar-
rowed outwardly at its base; fourth, ovate; fifth, largest,
broad, flattened outwardly, but narrowed at its base; sixth,
thin, pointed at the tip, with a slight indication of a joint at
its base. ‘Terminal feet with the basal portion large, exposed.
Terminal portion as long as the basal, conical. Inner appen-
dage slender, exserted.

THE type of this genus is closely allied to Oniscus
and Porcellio, but differs in its short flattened antenne,
scabrous, perfectly opaque, white body, as well as in
various minor structural details. The head has its
anterior lobes arranged nearly as in Armadillo, being
derived, according to Dr. Kinahan, from the cephalic,
mandibular, or fourth ring of the head, and not from
the third or second, z.e., the antennary rings. The third
is but badly developed and small, but the distinction
between it and the fourth ring is evident.

The internal antennze are three-jointed and _ very
minute; the outer antenne are short but broad, flat,
and scabrous, the fifth joint being much the largest,
and dilated. We have not been able, with a powerful
lens, to discover any articulation at the base of the ter-
minal joint, as described by Dr. Kinahan, although a
slight dilatation in the lateral margin near the base seems

PLATYARTHRUS. 463

to indicate the soldering together of two joints in that
situation. The segments of the body are moderately
convex, with a narrow lateral margin. The legs are
short, with the second and three following joints of
nearly equal size, terminated by a small hook-like finger,
having a small tooth on the inside near the middle. The
mandibles are strongly elbowed in the middle and ter-
minated with two compound teeth, and furnished with
a curved and setose spine in the middle of the mner
margin. (In our woodcut the mandible is represented
as lying on its back.) The two pairs of maxille are very
delicate, almost membranous, and ciliated at the tips.
The foot-jaws are oblong, flat, and coriaceous, each
terminated by two small quadrate lobes, which are trun-
cated at the extremity, where they bear one or two small
spines.

The articulation between the posterior appendages and
the last segment of the tail is very remarkable; the
latter is destitute of the epimeral coxe, and the ring is
continued beneath, terminating abruptly on either side
in a rounded lobe; so that the central portion of the
body underneath is unprotected. The posterior pair of
appendages are articulated to the anterior border of the
inferior (sternal ?) part of the ring, a little within the ex-
ternal lateral angle, by a well-marked ball-and-socket joint,
so that at first sight it appears as though these appendages
were derived from the penultimate and not from the
terminal segment. The posterior appendages are exserted,
the peduncular portion somewhat square, with the sides
parallel. The outer ramus is nearly as long as the base,
ovate, flattened, and pointed at the tip, where it is fur-
nished with a minute filament. The inner ramus forms
a slender filament, extending beyond the basal portion
against the inner side: it is articulated near the base.

4.64 ONISCIDA.

TSOPODA, ONISCID 4.
NORMALIA,

PLATYARTHRUS HOFFMANNSEGGITI,

Specific character. Opaque-white. Upper surface of the animal scabrous,
with compressed scale-like club-shaped prominences. Posterior margins of
the segments sub-serrated.

Length, one to one and three-quarters of a line.

Platyarthrus Hoffmannseggiit. Branvt, Bull. Soc. Nat. Moscow, vi. p. 174,
pl. 4, fig. 10 (antenna, absq. descr. specifica).
Hogan, in Nat. Hist. Rev. vi. p. 109.
Kinawan, in ditto, p. 127.

Ttea crassicornis (2). Kocu, in Contin. Panzer Ins. Deutsch]. 186,
fol. 5 ; and Deutschl. Crust. &c. 36, 5.

Tuts curious little species has much the aspect of a
Porcellio ; it is, however, considerably broader in propor-
tion to its size, the smallness of which, moreover, together
with its opaque-white colour, broad short antenne, sub-
terrestrial and ant-loving habits, well distinguish it.

The head is broader anteriorly than posteriorly, deeply

PLATYARTHRUS HOFFMANNSEGGIT. 465

immersed in the first segment of the body, and very
scabrous; the lateral lobes are much developed. The
antenne are scabrous, as are also the segments of the
body, the epimeral base of the legs forming the lateral
margins of the segments, with the posterior angles
directed downwards; the same part in the intermediate
rings of the tail are also well developed; the terminal
segment is triangular, emarginate on each side, with a
shallow pit on its upper surface, its posterior margin
tuberculated, as are also the posterior appendages
(uropoda).

The species was first noticed as British by the Rev.
A. R. Hogan, M.A., who found it in ants’ nests at
Lulworth Cove, near Weymouth, where he observed it
in as many as thirty nests of the common red, yellow,
and black ants, whilst about twice that number of nests
in the neighbourhood were not found to be frequented
by it. Previous to Mr. Hogan’s discovery we had
noticed the occurrence of these white Oniscide in the
nests of the common brown garden ant at Hammer-
smith, but thought they were merely the young of some
species of Porcellio. Since that time Mr. F. Smith has
also found the species in the neighbourhood of London,
and we have also again met with it in ants’ nests in the
neighbourhood of Stow Wood, near Oxford, in the early
summer months, as also at Berry Head, near Torquay,
where they were found by Master M°Guire Bate; and
near Plymouth, taken by Mr. Brooking Rowe.

VOL. Il. H H

466 ONISCID A,

ISOPODA, ONISCIDA.
NORMALIA.

Genus—ONISCUS. (Linneus.)

Generic character. Ovate, sub-depressed. Cephalon with
large lateral lobes extending outwards beneath the eyes. Outer
antenne eight-jointed ; second joint dilated at the base; seventh
and eighth joints sub-confluent. Coxee of the first, second, and
sixth segments of pleon obsolete; third to the fifth, broad and
curved, acute at tips. Terminal uropoda posteriorly exserted ;
apical portion ovate, pointed at tip. Inner lobe linear, short,
extending slightly beyond the telson, which is convex.

Tue species of this genus are typical of the family,
commonly called wood-lice, and are distinguished from
the other equally common species by having the ter-
minal portion of the outer antenne composed of three
joints, of which, however, the articulation between the
last and preceding joint is less distinct than the pre-
ceding.

The Philoscig, which have also eight-jointed setose
antenne, are distinguished at once from the Onisci by
the narrowness of the segments of the tail and the length
of its exserted terminal appendages.

‘‘The external angles of the superior margin of the
third ring of the head are produced into a broad lobe,
which covers over the origin of the external antenne ;
it is then continued across, projecting slightly over the
frontal line of the cephalic segment; the transverse
suture is well marked; the second ring very narrow,
almost obsolete. The lateral lobes are continued back-
wards, and are separated by a suture from the external

ONISCUS, 467

inferior border of the cephalic segment which completes
the orbits.”” (Kinahan.)

The structure of the mouth-organs is described under
the typical species O. asellus. ‘The first and second seg-
ments of the tail are visible only in the middle of the
dorsal surface, the lateral margins of the third segment
(of which the posterior angles are produced backwards,
and acute) forms a continuous line with the lateral
margins of the last segment of the body. The terminal
segment is also narrowed at its base; and if we draw a
line from its outer basal angles to the lateral angles of
the two basal segments, we shall perceive that the lateral
margins of the third, fourth, and fifth segments are pro-
duced outside of this line, and are strictly supplemental
appendages or lateral lobes.

The extremity of the terminal segment is produced
into a narrow and elongated point, its upper surface
being convex, the basal portion of the terminal appen-
dages extending to about half the length of this pro-
duced joint, of which the apex reaches the middle of
the outer division of the appendage; the inner lobe of
the basal portion is narrow and elongated, extending a
short distance beyond the extremity of the tail.

The species frequent damp situations, and have not
the power of rolling themselves into a perfect ball, but
attempt to do this in an incomplete manner, feigning
death when alarmed.

HH 2

468 ONISCID®.

ISOPODA. ‘ ONISCID 4.
NORMALIA.

cH U

ONISCUS ASELLUS.

Specific character. Broadly ovate, sub-depressed, shining ; covered with
smooth granules. Lateral lobes of the cephalon large, inclined backwards.
Frontal line somewhat emarginate. Terminal segment of the pleon elongate-
triangular, convex above. Intermediate segments of the pleon terminating
in acute angles.

Length, three and a half to eight lines.

Oniscus asellus. Liyy., Syst. Nat. ii. p. 1061. Dz Gump, Ins. vii. t. 35,
f. 1. Gzorrroy, Ins. Paris, ii. t.22,f.1. Lavrerue,
Hist. Nat. Crust. et Ins. vii. p. 42. Leacu, Edin. Ene.
vii. 406. Samovrenir, Ent. Compend. p.111. Jonsson,
Syn. Framst. Sver. Onise. p. 15. Wurrs, B. M. Cat.
Brit. Crust. p. 71. Pop. Hist. Brit. Crust. p. 234.

Oniscus murarius. Cuvier, in Journ. dHist. Nat. ii. t. 26, f. 11.
Fasricius, Ent. Syst. Suppl. p. 300. Branpr and
Ratzes., Arzn. Thiere, ii. t. 12, f. 7. Branpt, in
Bull. Mose. vi. p. 182. Mitnr Epwarps, Crust. iii.

ONISCUS ASELLUS. 469

p. 168. KinaHan, Nat. Hist. Rev. vol. iv. 1857,
p. 276, pl. xix. figs. 10, 11, 12, pl. xx. fig. 11), pl. xxi.
fig. 54. Burenrspivx, Annotat. p. 50. ScunirzueEr,
Onise. Agri. Bonn. p. 22.

Tue upper surface of the animal is glossy and deli-
cately punctured, as seen under a lens, the head and
segments of the body being dorsally furnished with
longitudinal raised spaces, leaving the posterior margin
of each smooth. The head is received within a deep
emargination of the anterior segment of the body, the
anterior angles of which extend even in advance of the
two prominent lateral lobes of the head. The inner
antennee are minute and three-jointed, the terminal joint
being the longest and most slender, with a slight setose
notch near the apex. The outer antenne have the basal
joint small, the second short, but broad and dilated at its
base on the outside; the fifth joint is the longest, the
three terminal joints being much more slender, and not
more than two-thirds of the length of the fifth joint (in
our magnified outline figure, c, the articulation between
the two terminal joints is much too strongly marked) ;
the tip of the eighth or terminal joint is furnished with
a minute spine.

The labrum is membranous, and composed of two divi-
sions, each of which is oblong in form, rounded at the
extremity, where is a deep narrow notch or fold, the
inner angle being somewhat more advanced, rounded off,
and finely setose: the right-hand division is represented
in figure /b’,

The mandibles are strong and horny, oblong in form,
strongly angulated on the outside, the apex being at
right angles with the base, and terminated by a compound
tooth, with three or four short curved spatulated bristles
along the margin, the inner angle of which is furnished

AZO ONISCIDA.

with a strong curved bristle, acute at the tip. The inner
maxilla are very delicate, and almost membranous,
oblique at the tip, with two curved setose bristles, the
base armed with two remarkable muscles. The outer
maxilla are narrowly oblong and rather curved, setose
at the outer margin, and spinose at the tip; the foot-jaws
are oblong, rounded on the outside, the external base
armed with a strong triangular lobe; the apex is divided
into two parts, the inner of which terminates in several
small teeth, and the outer in a movable finger-like lobe,
articulated at its base.

The legs are all cursorial, and are terminated by a foot
having a small tooth on the inside.

The branchial appendages on the underside of the
tail are arranged in pairs, the inner angle of the apical
margin being more or less extended backwards ; moreover,
in the males, the second pair of these appendages are
furnished at their base with a long style, dilated at its
base, pointed, and slightly curved at its tip. The ter-
minal pair of these limbs form the exserted biarticulated
appendages seen on either side of the acuminated ter-
minal joint of the tail; the two divisions of the last
pair are nearly equal in length, the middle of the
outer division extending to the tip of the tail. The
internal accessory lobe of the basal portion is slender,
and extends rather beyond the tip of the last joint of
the tail.

The general colour of this species is of a light greyish
brown or slaty lead, marked with blotches and spots of
yellowish white or buff, of which the most conspicuous
form a regular row on each side, parallel to the lateral
margins of the segments, the margins being also pale
with a dark spot; the dorsal spots are less distinct: a
salmon-coloured variety, with dark patches, is stated by

ONISCUS ASELLUS. 471

Professor Kinahan to be occasionally met with near the
sea.

This species is rarely found more than half an inch in
length, but we possess a specimen, of unknown locality,
measuring two-thirds of an inch. It is very common
throughout England, Scotland, and Ireland, under decay-
ing vegetable and animal matter, not only in damp, but
in the dryest localities. It is also common near the sea.

{t was formerly used in medicine, and was supposed to
cure agues, consumption, &c. It is commonly known
under the vulgar names of Pig’s-louse, Sows, Woodlouse,
Millepede, or Carpenter.

ONISCUS FOSSOR.

Specific character. Oval, sub-depressed, covered with numerous rough
granulations, which give it a powdered appearance. Cephalon convex,
Lateral lobes moderate, rounded. Frontal line produced into a triangular
lobe.

Length, five lines.

Oniscus fossor. Kocu, Dtsch. Crust. h. 22, n. 22 ; and in H. Scuarrer,
Contin. Panz. Faun. Ins. Germ. 162, fol. 22.
Kinawan, Nat. Hist. Rev. vol. iv. 1857, p. 277,
ple xxi, figs: 5565 7.

Oniscus muscorum. LEREBOULLET, Mém. Strasbourg, iv. p. 29.

Porcellio teniola. Kocu, Dtsch. Crust. h. 6, n. 2; and in H. Sowarr.
Cont. Panz. h. 139, n. 2 (var. 2).

Oniscus teniola. Ibid. h. 180, n, 20, note, and fig. 6 (var. 2).

THs species so closely resembles the preceding, that
we have not considered it necessary to give a figure of
it, which, indeed, without colours, would scarcely show
its chief distinction, consisting in the much more

472 ONISCID A.

opaque upper surface of the body, which is finely punc-
tured and furnished with the same kind of oblong
tubercles found in O. asellus, but more numerous and
closely arranged. ‘The head also is more prominent.
It is of a more uniform brownish-grey colour, although
exhibiting the same kind of pale patches and rows of
spots seen in that species. It also appears to be uni-
formly smaller than O. asedlus.

We have adopted the reference to Koch’s figure of
Oniscus fossor, which Professor Kinahan states to be very
characteristic, although the flagellum of the antenne is
only represented with two instead of three joints, as in
the type of the genus.

This species inhabits dry places under stones and dry
leaves. It is more active than the preceding species. It
has been taken in Epping Forest and Chiselhurst, Kent,
and near Dublin and Wexford, in Ireland. Specimens
are in the British Museum, as well as in the Stephensian
Collection of Crustacea at Oxford, purchased by the
Rev. F. W. Hope, the latter being named O. asellus ;
and the Rev. A. M. Norman records it from Sedgefield,
Co. Durham.

PORCELLIO. 473

ISOPODA. ONISCIDA.
NORMALIA,

Genus—PORCELLIO. (Latreille.)

Generic character. Ovate, sub-depressed. Cephalon with
large lateral lobes. Outer antenne seven-jointed. Coxe of
the second and sixth segments of pleon obsolete. Terminal
uropoda with the basal portion triangular, flattened. Apical
portion compressed, trigonate, exserted. Inner appendage small,
curved, and trigonate, concealed by the last segment of the
pleon, which is more or less concave on its upper surface.

Tue animals of this genus differ from those of
Armadillo (which they resemble in having only seven-
jointed outer antenne), in the form of the second
joint of those organs, which is not furnished with
a rounded lobe on the outside at its extremity—a
peculiarity dependent on the different arrangement of
the front part of the head, and the consequent manner
in which these organs are disposed when at rest, the
remarkable groove at the sides of the front of the head
being here wanting. The late Professor Kinahan thus
described the structure of the front of the head in
Porcellio :—

“External angles of the third antennary segment of
the head more developed than in Oniscus, the superior
margin raised into a lobe, which projects above the
frontal line of the cephalic segment, and gives the head
a trilobed appearance. This lobe, though sometimes
badly marked (Porcellio pruinosus, Br.—P. frontalis Lereb.,
not Edw., for example), is present in all the species I
have had an opportunity of examining.”

474 ONISCIDA.

The inner antenne are very minute and four-jointed,
the second joint in some of the species appearing to be
formed of several minute rings. The outer antennz are
seven-jointed, the basal joint also occasionally appearing
as if formed of two portions. The base of the second
joint is dilated; the fifth joint is long and somewhat
slender, being considerably longer than the two terminal
joints united. The details of the mouth-organs are
described under Porcellio scaber, and need not, therefore,
be here given. The elongation of the terminal appen-
dages of the tail, to a considerable length beyond its
extremity, also distinguishes these animals from Arma-
dillo, the inner lobe of the basal support being even
occasionally visible beyond the terminal joint of the
tail.

PORCELLIO SCABER. 4T5

ISOPODA. ONISCIDA.
NORMALIA.

ant =

Roc
2 (5.7.0

\ y/
Vvuv yuu]

N

PORCELLIO SCABER.

Specific character. Hlongate-ovate, rugose. Lateral processes of the
cephalon very prominent, with the external angle rounded. The middle pro-
cess triangular. Last joint of the pleon ending in a sharp triangular point,
deeply sulcated down the middle.

Length, nearly half an inch.

Porcellio scaber. LATREILLE, Hist. Nat. Crust. et Ins. vii. p. 45.
Gen. Cr. et Ins. i. p. 70. Leacu, in Trans, Linn.
Soe. xi. p. 375. Edinb. Ene. vii. p. 406. Suppl.
Ene. Brit. 1429. Samovetiy, Ent. Comp. p. 112.
Dusmarust, Cons. Crust. p. 8321. Gufirin-Minev.
Icon. R. An. Crust. t. 31, f. 7. Minne Epwarps,
Crust. iii. p. 167. Cuvirmr, Régne An. (Edit.
Crochard), t. 71, f. 1. Kinanan, Nat. Hist. Rev.
vol. 4, 1857, p. 277, pl. xxi. figs. 2and 8. Kocn,
in Cont. Panzer Heft. 180, n.6 and7. Wuurs, B.
M. Cat. Brit. Crust. p. 72. Pop. Hist. Brit. Crust.
p. 237, pl. xiii. fig. 2. Branpr and Rarzmpura,

476 ONISCIDA,

Arzn. Thiere, ii. tab. 12, f. 1, 2, 3, 4. Jounsson,
Syn. Framst. Sver. Onise. p. 21. Zappacu, Syn.
Crust. Pruss. p. 12. Bureerspiyx, Annot. p. 89.
ScHNITZLER, Onise. Bonn. p. 28.

Oniscus granulatus. Lamarck, Hist. Anim. sans Vertébr. vy. p. 261.

Porcellio dilatatus. Branpt and Rarzes., Arzn. Thiere, t. 12, f. 6.
Branpt, Bull. Moscow, vi. p. 176.

Oniscus asellus. Fasricius, Ent. Syst. Suppl. p. 300.

Porcellio Brandtit. Minne Epwanps, Crust. iii. 168 (var.).

Porcellio dubius. Kocu, in Cont. Panz. Heft. 180, n. 8.

Porcellio affinis. Koon, in Cont. Panz. Heft. 180, n. 13 (var.).

Tus species is at once distinguished by the entire
upper surface of the animal being strongly marked with
round and elevated tubercles. The lateral lobes of the
head are very prominent, and rounded at the outer
angles, whilst the central lobe is strongly produced and
nearly triangular. The animal is more or less ovate in
form, and moderately convex, with the posterior angles
of the segments of the body moderately produced and
pointed. The outer antenne have the second joint
dilated internally at its base. The fifth joint is the
longest, and the two terminal joints united are about
two-thirds of the length of the fifth. The upper lip is
formed of two flattened membranous plates, of each of
which the outer apical angle is rounded, and the inner
angle slightly extended, dilated, and setose. The right-
hand division of this lip is represented in figure 1b’. The
mandibles are horny, strongly angulated on the outside,
the extremity being at right angles with the base, and
armed with three teeth, which seen laterally are obliquely
truncated. Below this, the inner margin of the mandible
beyond the middle is armed with a complicated series of
short horny teeth and bristles, the innermost of which is
elongated and curved. The inner maxille are delicate,
and armed at the tip with two setose_bristles ; the outer
maxillz are large, oblong, setose on the outer edge, and

PORCELLIO SCABER. 4.77

spinose at the tip. The foot-jaws are formed of a pair
of large oblong plates, having an elongated horny sup-
port on the outside arising from their base. The ex-
tremity of each is furnished with a number of minute
teeth, the inner ones arising from a distinct but very
short lobe or division.

The terminal appendages of the tail are robust, with
the outer division triangularly ovate, and extending
about half its length beyond the extremity of the telson
or terminal segment of the tail, which ends in a sharp
triangular point, having a groove along the middle of its
dorsal surface, and which completely covers and conceals
the elongated accessory plate of the base of the apical
appendages.

The colour of this species is uniformly of a greyish
black or slaty grey, more or less strongly spotted with
yellow ochre or whitish buff. A nearly uniform salmon-
coloured variety also occurs, and it is very probable that
others of the supposed species figured by Koch may be
only varieties.

In P. dubius of Koch, the pale spots are wanting, the
uniform colour being blackish. In his P. affinis there
is a pale lateral line parallel to each side, running
through the whole of the segments of the body.

The species runs with agility, and partially rolls itself
into a ball when alarmed. It has been observed feeding
on living caterpillars, frequenting moist places where
decaying vegetation is found, and even among sea-weed,
in company with Ligia, &c. We have also found it
partial to growing vegetables, and it appears to possess
a strong partiality for nearly ripe wall-fruit. It is very
widely distributed throughout England and Ireland. The
female may be found with eggs contained in the ventral
pouch throughout the year.

478 ONISCID &.

ISOPODA. ONISCID:.
NORMALIA.

PORCELLIO DILATATUS.

Specific character. Very broad, depressed, rough, and granular. Lateral
frontal processes very prominent, rounded at the apex, and concave. Median
lobe obtusely triangular, moderately developed. Terminal segment of the
pleon rounded at its apex, nearly flat above. Terminal plate of uropoda flat
and broadly ovate, pointed at the tip.

Length, five to seven lines.

Porcellio dilatatus. Branpt, Bull. Mose. vi. p. 176. Branpt and Rarze-
BurG, Arzn. Thiere, ii. pl. 12, f. 6. BureaerspivK,
Annot. p. 44. Kryanay, Dublin Nat. Hist. Rev.
vol. 4, 1857, p. 278. Scunirzter, Onise. Bonn.
p. 23.

Porcellio scaber. Mitne Epwarps, Crust. iii. p. 167.

Tus species is ordinarily much larger than P. scaber,
from which it is easily distinguished by its very broad
form, and by the less scabrous surface of its body. The
outer antenne are rather short, with the two terminal

PORCELLIO DILATATUS. 4:79

joints of nearly equal length. The lateral lobes of the
front of the head are large, and curved rather outwards ;
they extend rather beyond the anterior angles of the
first segment of the body, which, together with the two
or three following segments, are marked with rather
oblique and slender lines and rugosities. The terminal
segment of the tail has the sides of the apical half
nearly parallel, and the tip itself rounded.

It is of an uniform slaty-grey colour, with faint
irregular pale lines and spots indicating the chief
rugosities.

It is found amongst decaying grass and straw, and
appears to be extremely rare. It crawls very slowly,
and partially rolls itself into a ball. It is very brittle
in its texture, a touch causing the limbs to fall off.

Specimens are preserved in the British Museum, found
by Prof. Kinahan, from the neighbourhood of Dublin.

480 ONISCID A.

TSOPODA. ONISCIDA,
NORMALTIA.

9 9 iP,

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9000 9000

ps fe}

PORCELLLO PICTUS.

Specific character. Slightly elongated, moderately granulated, upper sur-
face glossy. Lateral lobes of the cephalon very prominent, curved outwards and
downwards ; the median lobe small and curvilinear. Terminal segment of
the pleon triangular, acute at the apex, sulcated above.

Length, about one-third of an inch.

Porcellio pictus. Branpt and RatrzeBure, Arzne-thiere, ii. pl. 12,
f. 5. Conspect. Mon. Onisc. Bull. Mose. vi.
p. 176. Minne Epwarps, Crust. iii. 166.
Krnauan, Dublin Nat. Hist. Rev. vol. 4, 1857,
p- 278. Jounsson, Syn. Framst. Sver. Onisc.
p. 22. BuraurspiyxK, Annot. p. 46.

(Var.) P. serialis. Kocu, Cont. Panz. Heft. 180, n. 18.
(Var.) P. crassicornis. Kocu, Cont. Panz. Heft. 180, n. 19.
(Var. ?) P. conspersus. Kocu, Cont. Panz. Heft. 180, n. 17. Zappacu,

Syn. Crust. Pruss. p. 12 (?).
Porcellio melanocephalus. ScHNITZzZLER, Onisc. Bonn. p. 24 (and Kocu 2).

FINELY-MARKED specimens of this species are amongst
the handsomest of the British Isopods. The general

PORCELLIO PICTUS. 481

form of the body is that of P. scaber, but the compara-
tively small amount of granulation of the upper surface,
with the short triangular terminal segment of the tail
pointed acutely at its tip, will serve to distinguish it,
independent of its coloration and marking.

The head is entirely black and strongly granulated,
the granules of the hind part of the head being arranged
in transverse rows; the ground colour of the remainder
of the animal is that of yellowish clay. The anterior
half of the first segment of the body has a black streak
extending down the middle, on each side of which is a
bright yellow patch, with a black spot on each side
behind the eyes. ‘These spots reappear in the following
joints, the central black one being widened, and the yellow
one on each side nearly forming a ring, enclosing a dark
spot and some dark dots; the lateral margins are yellow,
with groups of black dots near the edges, and a sub-
marginal black streak on each side parallel with the
margin. The basal portion of the apical appendage
of the tail is yellow, and the broad outer division black,
with the tip pale. The outer antenne are dusky, the
sixth joint being evidently longer than the terminal one.

The several varieties above quoted, given as distinct
species by Koch, vary in the greater or less clearness of
the dark longitudinal stripes down the back ; in P. serzalis
these dark stripes alternate in nearly equal width with
the intervening pale ground of the body, leaving in fact
a pale central and two narrow streaks parallel with the
sides of the body, together with a broader or less clearly
defined one on each side of the dark lines at the edges of
the central pale one.

In its general form and appearance it resembles Oniscus
fossor, from which it however differs in being far more
glossy and variegated in colour,

VOL. II. ig

482 ONISCIDA.

It appears to affect dry situations, such as the rubbish
in old ruins, and under dry leaves. It runs with great
agility, and does not roll itself into a ball.

The neighbourhood of Dublin and Belfast in Ireland,
and Chiselhurst in Kent, in England, have been recorded
as the localities of this species; in the latter situation it
was found in chalk pits.

THE KERRY ANCHOR.

PORCELLIO LAVIS. 483

ISOPODA. ONISCID A.
NORMALIA,

~

PORCELLIO LAVIS.

Specific character. Very convex, smooth. Lobes of the sides of the front
of the cephalon slightly prominent, small, and rounded at the outer angle ;
middle lobe very short. Terminal segment of pleon rounded at the tip,
deeply suleate down the middle. Uropoda considerably elongated.

Length, three-quarters of an inch.

Porcellio levis. LatreInye, Hist. Nat. Crust. et Ins. vii. p. 46; Gen. Cr.
et Ins. i. p. 70. Lamarcx, Anim. s. Vertébr. t. 5,
p. 154 (Oniscus 1.). Mitye Epwarps, Crust. iii.
p- 169. Krnawan, Nat. Hist. Rev. vol. iv. 1857,
p. 278. Wuurs, B. M. Cat. Brit. Crust. p. 72. Pop.
Hist. Brit. Crust. p. 237. Jonsson, Syn. Framst.
Sver. Onise. p. 27. Zappacu, Syn. Crust. Pruss. p. 13.

Cylisticus levis. Scuyirziur, Onisc. Agri Bonn. p. 25.

Turis is the largest British species of the genus, and
is well distinguished by the smooth upper surface of the
animal, the small lateral lobes of the face, and the great

1

4,84: ONISCID.

length of the two terminal appendages of the tail. Herr
Schnitzler has, indeed, proposed to form it into a separate
genus, Cylisticus, on account of the convexity of the
terminal segment of the tail, the rectangular lateral
termination of the segments of the body, and the curious
character (to which he has first directed our attention)
that each of the false feet, or branchial plates of the tail,
are marked with small white spots at the base; whereas
in the other species it is only in the first and second pairs
of those organs that this character is to be found. These
characters do not appear to us, however, to be of suffi-
cient importance to warrant the establishment of a new
genus for the P. levis.

Its colour is of a leaden grey, occasionally blotched
with yellow on the sides. It is sluggish in its habits,
and occurs commonly in stable-litter, and among grass at
the bottom of walls.

It occurs in England and Ireland. Kent, and the
neighbourhood of London and Dublin, have been re-
corded as the localities.

PORCELLIO ARMADILLOIDES. 485

ISOPODA, ONISCID E.
NORMALIA,

PORCELLIO ARMADILLOIDES.,

Specific character. Elongate-elliptical. Segments very convex and smooth.
Lateral lobes of the front of the cephalon minute, obliquely truncated in
front. Central lobe very short, angular, and acute. Terminal segment of
the pleon acute, flat above, or slightly convex.

Length, half an inch.

Porcellio armadilloides. LEREBoutteT, Mem. Soc. Nat. Hist. Strasbourg,
iv. 1853. Kinanan, Dublin Nat. Hist. Rev. iv.
1857, p. 279.

Oniscus convexcus. Dre Greer, Mem. Ins. vii. p. 553, pl.£35, f. 11.
Jounsson, Syn. Frams. Sver. Onise."p. 32.
Oniscus saxatilis. HARTMANN.

Tuis species is well distinguished by its narrow and
almost cylindrical form, reminding the observer strongly
of the species of the genus Armadillo. The lobes of the
head are but slightly developed, the lateral ones having a

486 ONISCIDA.

rounded margin and a concave upper surface. The seg-
ments of the body have the posterior angles acute. The
third, fourth, and fifth segments of the tail are largely
developed, their lateral margins being continuous with
that of the sides of the body-segments. The terminal
segment of the tail is elongate-conic, and pointed at the
tip, with the upper surface slightly convex, and extending
to about one-third of the length of the outer division of
the terminal appendages of the tail, which are elongate,
slender, and pointed at the tip. The general colour is
iron-grey, with clear borders to the segments, and with a
row of ill-defined whitish spots on each side of the body,
parallel with the lateral margins. When alive, it rolls
itself into a perfect ball on being alarmed.

Specimens taken near London (at Highgate ?) by Mr.
Francis Walker, are in the cabinet of the British Museum.

PORCELLIO PRUINOSUS. 487

ISOPODA. ONISCID.
NORMALIA.,

30
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° Poo o 02 0°S 2°

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oO

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PORCELLIO PRUINOSUS.

Specific charucter. Subovate, oblong, slightly rugose, and downy. Lateral
lobes of the front of the cephalon small and rounded. Central lobe minute,
almost linear. Pleon narrow, with the terminal segment triangular, acute at
the apex. Pereiopoda long.

Length, about one-third of an inch.

Porcellio pruinosus. | Branpt, Conspectus Mon. Onise. Bull. Mose. vi. p. 181.
Kryawan, Dublin Nat. Hist. Rev. vol. iv. 1857,
p. 278, pl. 19, figs. 3, 5, 7, pl. xxi. fig. 1.

Porcellio frontalis. LEREBOULLET, Mem. Soc. Hist. Nat. Strasbourg, iv.
1853 (not of Minne Epwarps). Jonnsson, Syn.
Framst. Sver. Onise. p. 30.

(Var.?) P.maculicornis, Kocu, Cont. Panz. Heft. 180, n. 16. Bureurspiux,
Annot. p. 48.

Tuts species, although one of the commonest of our
British wood-lice, was first detected by the late Professor

488 ONISCIDA.

Kinahan, having been confounded with P. scaber, from
which, however, it is at once distinguished by its more
elongate form, less rugose surface, and especially by the
narrowness of the tail, in which respect it approaches
the species of the genus Philoscia. The posterior angles
of the three anterior joints of the body are obtuse, and
those of the following joints are much less acutely pro-
duced backwards than in most of the other species of
the genus. The lobes of the head are but slightly pro-
duced, the central one being small and rounded. The
tail is small, the three principal segments being com-
paratively minute, as compared to their size, in the
preceding species. The terminal joint is short and
triangular, its extremity only extending a little beyond
the base of the terminal division of the apical appen-
dages of the tail, which is considerably elongated, as are
also the legs; the whole structure of the animal indi-
cating greater activity and powers of movement.

The variety P. maculicornis of Koch is of an iron
colour, with the outer antennz ringed with white, the
segments of the body having the posterior margins
simply granulated, and the terminal appendages of the
tail of a ferruginous colour,

The species is of an uniform mouse-grey colour, seen
under a lens to be marked with white. It generally con--
ceals itself rapidly from the light, but, when disturbed,
runs with great rapidity. It prefers moderately humid
warm situations, and occasionally buries itself in the
earth, even in clayey localities, to a considerable depth.
It is very common both in England and Ireland. The
neighbourhoods of Dublin and Chiselhurst, Kent, are
localities in which they are found. It is equally plen-
tiful in the vicinity of Oxford.

PORCELLIO CINGENDUS. 489

ISOPODA, ONISCIDA:.
NORMALIA.

PORCELLIO CINGENDUS.

Specific character. Hlongate-ovate, smooth or but slightly scabrous, glossy.
Lateral lobes of the front margin of the cephalon minute and deflexed ; the
median one nearly obsolete. Terminal segment of the pleon broadly trian-
gular, flat above, with the apex acute.

Length, nearly one-third of an inch.

Porcellio cingendus. Krnawan, Dublin Nat. Hist. Rev. vol. iv. 1857,
p- 279, pl. xix. figs. 1, 2, 4, 6, 8, and 9.

THE minute development of the lateral and frontal
lobes of the anterior margin of the head, the narrowness
of the segments of the tail, and the broadly triangular
terminal segment of that part of the animal, well dis-
tinguish this species from most of its congeners; whilst
the smooth shining body, and the rounded postero- lateral
angles of the segments of the body, serve to separate it

490 ONISCIDA.

from P. pruinosus, in company with which it is often
found, and of which it might be mistaken for the young,
which latter, however, do not differ from their parents.
The basal portion of each of the segments of the body
is marked with a transverse raised line, whence the name
given by Professor Kinahan to the species. It is of a
dark steel colour, with red and yellow spots. It runs
with very great rapidity, and never rolls itself into a
ball, as might indeed be surmised from the small develop-
ment of the lobes of the head, which form, in other
species, the defence of the antennez when at rest.

It is very rare. Specimens taken near Dublin by
Professor Kinahan, are in the collection of the British
Museum and our own cabinet.

ARMADILLO. 49]

ISOPODA. ONISCIDA.
NORMALIA.

Genus—ARMADILLO. (Latreille.) *
ARMADILLIDIUM. (Brandt.)

Generic character. Elliptical, very convex. Outer antennes
seven-jointed. Coxe of the first and sixth segments of the
pleon obsolete. Uropoda with the basal portion flattened, trun-
cate; terminal portion broader than long, not extending beyond
the extremity of the pleon, with which its apical margin forms
a continuous line; accessory filament flattened, club-shaped,
concealed.

Turs genus forms a distinct section of the family on
account of the structure of the last pair of the appen-
dages of the tail, which do not extend beyond the
extremity of that part of the body, their trurcated
extremity forming a continuous line with the lateral
margin of the fifth segment of the tail, and the extremity
of the sixth joint.

“The eyes are supported on the cephalic segment
alonee ‘The margin of this is raised, forming an angular
projection in the middle of the forehead, passing back
from whence, as it forms the orbital margin, to the entire
exclusion of the third segment, the lateral lobes being
here remarkably small, and derived entirely from the
cephalic segment.”—Kinahan.

The animals, when alarmed, have the habit of rolling
their bodies into a perfect globular mass, the antennz
being completely concealed, for which purpose the front
margin of the head is provided with a groove on each
side, within which the basal joints of the outer pair of
these organs are lodged (fig. A).

* The Mammalians thus popularly named being generically known under
the name of Dasypus, we have retained Latreille’s name of Armadillo, which
has been generally adopted for these Crustaceans.

492 ONISCID®.

ISOPODA. ONISCID A.
NORMALIA,

ARMADILLO VULGARIS.

Specific character. Elliptical, very convex, upper surface delicately pune-
tured ; of a dark leaden or steel-grey colour, with paler spots, and with the
hind margins of the segments generally pale. Second joint of outer an-
tenn with the tip dilated at its outside. Uropoda with the outer division
broad, short, exactly filling the space between the sides of the terminal and
penultimate segments of the pleon.

Length, about half to two-thirds of an inch.

Oniscus armadillo. Linnavs, Syst. Nat. ii. p. 1062.

Armadillo vulgaris. LATREILLE, Hist. Nat. Crust. et Ins. vii.
p. 48. Genera Crust. et Ins. i. p. 70.
Leacu, Edinb. Encycl. vii. p. 406.
Trans. Linn. Soc. xi. p. 376. Suppl.
Ene. Brit. i. p. 429. Samovenun, Ent.
Compend. p. 112. Dxsmarerst, Cons.
Crust. p. 825. Wuuirtn, Cat. Brit. Crust.
p. 73. Pop. Hist. Brit. Crust. p. 238.

ARMADILLO VULGARIS. 493

Armadillidium vulgare. MinyeE Epwanps, Crust. iii. p. 184. Bur-
GERSDIJE, Annot. p. 51. Zappacu, Syn.
Crust. Pruss. p. 19. JoHnsson, Syn.
Framst. Sver. Onise. p. 34.

Armadillium vulgare. Kinauan, Nat. Hist. Rev. vol. iv. 1857,
">. 276, pl. xxi. figs. 3, 9—13.

Oniscus cinereus. ZENKER, in Panzer, Heft. 62. n. 22.

(Var.) Armadillo variegatus. LATREILLE, Gen. Cr. et Ins. i. p. 72, n. 2.

Kocu, Cont. Panzer, Heft. 178 n. 15,
and 186, n. 2.

Armadillidium Zenkeri. Branpt, Consp. Mon. Crust. Onisc. Bull.
Mose. vi. 185.

(Var.) Armadillo opacus. Kocu, Cont. Panz. Heft. 180, n. 3.

(Var.) Armadillo Williz. Kocu, Cont. Panz. Heft. 186, n. 1.

Armadillo pulchellus. ScHnitzueR, Onisc. Bonn. p. 26 (2).

Tuts very widely dispersed species is subject to great
variation in the amount of its pale markings, which has
led to the establishment of a great number of supposed
species, as appears from the citations quoted above.
We have not been able to recognize more than a single
species amongst them, which is well distinguished by the
perfectly globular form in which it is able to roll itself
up when alarmed, as represented in the lower left-hand
figure of the accompanying wood-cut. The extremity
of the tail and of the flattened truncated appendages of
the last caudal segment exactly coincides with the front
margin of the head, completely concealing the deflexed
antennee and legs.

The head is produced on each side immediately below
the eye into a short transverse ridge, forming the upper
edge of a groove, within which the basal joints of the
antenne are lodged; the lower edge of the groove
being also produced into a moderately prominent
rounded lobe. The labrum or upper lip is triangular,
and transversely prominent along its straight upper edge.
The inner antenne are very minute and apparently
three-jointed, the middle joint being the smallest, but

494, ONISCIDA.

under a strong magnifying power the rudiments of two
very minute terminal joints are to be perceived, as well
as several short thickish spines. The large outer antennze
are seven-jointed, the second joint roundly dilated at its
outer edge at the tip, the fifth joint long, the seventh the
slenderest, with a minute distinct seta at the tip.

The third segment of the tail is laterally continuous
with the edge of the seventh segment of the body, the
two basal segments of the former, although quite dis-
tinct, being short and greatly abbreviated at the sides.
The hind margin of the fifth segment is semicircular,
the emargination being filled in by the small triangular
sixth segment, of which the apex is obtuse, and by the
flattened and truncated outer division of the first pair of
false legs, the inner division being small, flattened, and
ovate. The five anterior pairs of appendages of the tail
differ considerably in form, the first pair being composed
of two flattened, somewhat triangular, plates ; the second
pair in the male is nearly similar in form, but is provided
with a large pair of elongated horny lobes, slightly
curved at the tips; the third pair in the male is more
sabre-shaped, with a slender horny appendage, having the
tip bent and acute; the fourth, fifth, and sixth pairs have
the plates triangular-shaped.

The general colour is leaden, or dark steel-grey, with
spots and patches of dull buff or whitish: it varies,
however, to brownish testaceous. It inhabits rather dry
places under stones, decaying timber, and among herbage,
and is often seen running about foot-paths, rolling itself
up into a ball at the least alarm. This has gained for it
the name of P2ll millepede, and in ‘‘ former times it was
highly reputed for its supposed medicinal virtues, the
old books of Materia Medica informing us that when
dried and pulverized they have a faint disagreeable

ARMADILLO VULGARIS. 495

smell, and a somewhat pungent, sweetish, nauseous taste,
and are highly celebrated in suppressions, in all kinds of
obstructions of the bowels, in the jaundice, ague, weak-
ness of sight, and a variety of other disorders.” And the
wine of Millepedes, prepared by crushing these animals
when fresh, and infusing them in Rhenish wine, is spoken
of as an “admirable clearer of all the viscera, yielding to
nothing in the jaundice and obstructions of the kidneys.
In the light of modern science, we can impute the cures
attributed to these creatures only to the effect produced
upon the imagination of the patient, and the curative
powers of nature, for, beyond some slight demulcient
qualities, they must be wholly inert, and are now wisely
discarded from the Pharmacopeias.” (Fitch, in Report
on Noxious, Beneficial, and other Insects of the State of
New York. Albany, 1855.) They are still taken medi-
cinally in some parts of Somersetshire.

The species is very widely dispersed and very common.
Its recorded localities are near London, and in Kent,
and generally throughout Ireland. It is very abundant
in the Midland counties, as well as in Devonshire and

Cornwall.

Ase ie? HAN 1D) bX.

SALTATORIA. (Vol. I. p. 37.*)

ORCHESTIA BREVIDIGITATA, N.S,

Specific character, Second pair of gnathopoda with the propodos broader
at the distal extremity; the palm being at right angles with the upper
margin, nearly straight, fringed with a series of equidistant sete, and
bounded below by an obtusely rounded lobe.

Length, about eight-twentieths of an inch.

Tus species differs from any that we have hitherto examined,
Tt bears a closer resemblance to O. euchore, which Dr. Fritz
Miller has described, from the shores of Brazil, than any
other with which we are acquainted.

The most striking feature is that of the form of the second
pair of gnathopoda, as described above.

The dactylos of the second pair of gnathopoda is nearly
one-third shorter than the palm, and one-half the width of

VOL, II. K K

498 APPENDIX.

the distal margin of the propodos. In O. euchore the hand
is more ovate, and the dactylos reaches to the extremity of
the palm.

The hand of the second pair of gnathopoda is smaller in
proportion than that of the male in other species, which,
together with the size of the animal, incline us to believe the
specimen to be a not yet fully grown animal.

We are indebted for this species to Mr. Edward, who took
it near Banff. Its eyes are black, and its colour a light
olive-green. It probably has been passed over for the young
of the more common species.

APPENDIX. 499

AMPHIPODA. STEGOCEPHA LIDES.
NATATORIA, (Vol. I. p. 66*.)

MONTAGUA CLYPEATA.

Specific character. Second pair of gnathopoda with the propodos oblong,
slightly widening to the distal extremity, where it is truncated, terminating
below in a porrected point ; the palm slightly curved and serrated.

Length, three-twentieths of an inch.
Montagua clypeata. Sprnce Barr, Cat. Amph. B. M. p. 58, pl. ix. fig. 4

Leucothoé clypeata. Kroy., Nat. Tids. iv. p. 141, pl. 6, fig. 2a. LiLsEBore,
in Ofvers. af Kongl. Vetensk. Forhandl., 1851.

Somn specimens, taken by the Rev. A. M. Norman off the
coast of Northumberland, agree so closely with the description
and figures of Kroyer above referred to, that we have little
doubt but that they belong to the species which he has de-
scribed under the above name. ‘The form of the hand of the
second pair of gnathopoda, of which we give a figure, bears
such a relation to that which we have described as belonging
to M. pollexiana, that we are inclined to believe that Kroyer’s
specimen may be but the female of ours. But this is yet to
be determined, in which case our species would yield its name
to the earlier one of Kroyer.

keke

500 APPENDIX.

AMPHIPODA. STEGOCEPHALIDES.
NATATORIA. (Vol. I. p. 66.**)

MONTAGUA NORVEGICA.

Specific character. Second pair of gnathopoda having the propodos large
and oblong, armed in the middle of its under edge with a strong projecting
tooth, reaching as far as the under angle of the serrated palm.

Length, about a quarter of an inch.

Montagua norvegica. Sv. Bars, Cat. Amph. B. M. p. 370.
Leucothoé norvegica. LintsEBora, Ofvers. af Kongl. Vet. Akad. 1850, p. 335,
Bruzenivs, Skand. Amph. Gam. p. 97.

Tus species appears to agree with Lilljeborg’s description
of Leucothoé norvegica, chiefly in the formation of the propodos
of the second pair of gnathopoda.

The hand is large, and armed with a strong sharp tooth
that projects from near the middle of the lower or posterior
margin, the apex of which reaches to a line with the palm,
from which it is separated by a deep excavation, the anterior
margin of which is directed in a line parallel with the anterior
margin of the propodos. The palm is straight, furnished
with five small broadly based denticles. The dactylos*reaches
beyond the palm, but does not extend to the extremity of the
thumb-like tooth of the hand.

This species was taken near Banff by Mr. Edward.

APPENDIX. , 501

AMPHIPODA. LYSIA NASSIDES.
NATATORIA. (Vol. I. p. 118.*)

Genus—OPIS. (Aroyer.)

Generic character. Resembles Anonyx, with the exception that
the first pair of gnathopoda have the inferior angle of the propodos
considerably produced, so that the hand is formed into a didactyle
chela.

OPIS LEPTOCHELA, N.S.

Specific character. Upper antennz with the two basal joints large ; lower
antenne half as Jong again as the upper. Both pairs of gnathopoda minute,
slender, and subequal.

Length, about one-fourth of an inch.

Tue cephalon is small, not produced anteriorly. The
segments of the pereion and pleon are dorsally subequal in
length ; the fourth segment of the pleon having a deep notch on
the dorsal surface. The eyes are small and round. The first
two joints of the superior antennee large ; the flagellum short ;
secondary appendage short. The inferior antenne are slender,
being half as long again as the superior. Coxe deep. Gnatho:

502 APPENDIX.

poda slender, cylindrical, subequal; first pair having the
propodos nearly as long as the carpus; inferior angle longi-
tudinally produced to a fine point, slightly curved; dactylos
as long as and parallel with the digital process of the pro-
podos: second pair rather more slender than the first, with
the propodos nearly as long as the carpus, and furnished with
a copious brush of hairs; dactylos minute, simple, almost
lost in the cilia of the preceding joint. Periopoda short and
robust.

Specimens of this species have been taken by the British
Association Dredging Committee in the Shetlands, and by
Mr. G. Brady, on a specimen of Hchinus esculentus, off the
Isle of Man.

APPENDIX. 503

AMPHIPODA. LYSIANASSIDES.
NATATORIA. (Vol. L. p. Bs **))

OPIS QUADRIMANA, N.S.

Specific character. Upper antenne with the secondary appendage nearly
reaching to the extremity of the flagellum. First pair of gnathopoda with
the propodos quadrate, truncated at the end, the inferior angle armed with a
strong pointed spine.

Length, one-eighth of an inch.

Tuts species differs from the preceding in having the
superior antennse longer, and furnished with a secondary
appendage that reaches nearly to the extremity of the flagel-
lum; the inferior antennee being scarcely longer than the
superior, and in the first pair of gnathopoda being much
more robust than the second. The propodos of the first pair
is quadrate, the palm being at right angles with the anterior
and posterior margins, and armed with a minutely denticu-
lated thickened margin ; inferior angle produced to a short
strong tooth, against which the apex of the slightly curved
dactylos impinges.

This species was sent to us by Mr. Edward, who took it off
the Banffshire coast.

504 APPENDIX.

AMPHIPODA. AMPELISCIDES.
NATATORIA. (Vou. I. p. 137.%)

AMPELISCA LAVIGATA,

Specific character. Posterior margin of third segment of pleon regular,
Superior antennz attached to the lower angle of the anterior margin of the
cephalon.

Length, about one-fifth of an inch.

Ampelisca levigate. Liuusezore, Ofvers. af Kongl. Vet. Akad. Forhandl.
Spence Bars, Cat. Amph. B. M. p. 96.

We have received from the Rev. A. M. Norman a specimen
that probably belongs to this species. It differs little from
A. belliana, except in the absence of the ornate character of the
posterior margin of the third segment of the pleon, and in
having the superior antenne attached to the lower angle of
the anterior margin of the cephalon.

It was taken off the coast of Durham. Lilljeborg obtained
his specimen at Kullaberg, on the coast of Norway.

APPENDIX. 505

AMPHIPODA. AMPELISCIDES.
NATATORIA, (Vol. I. p. 137.**)
-————A

anineage
ff \ Na IN 1 Ek
f SSN 5 HCW RES
UES <S rill aS Ws SLES > < =~
SS Ss iw —

Genus—HAPLOOPS. (Lilljeborg.)

Generic character. Closely allied to Amipelisca, but differs in
having the cephalon less anteriorly produced, and the organs of
vision reduced to two.

HAPLOOPS TUBICOLA,.

Specific character. Superior antenn about one-third of the length of the
animal, ciliated beneath, without an accessory filament. Two pairs of gnatho-
poda small and hairy. First and second pereiopoda terminated by long stylate
fingers.

Length, about half an inch.

Haploops tubicola, LituvEBORG, Ofvers. af Kongl. Vet. Akad. 1855.
Bruzetivus, Skand. Amph. Gam. p. 88. Spnnou
Bats, Cat. Amph. B. M. p. 371.

Ampelisca Eschrichtii? LrutsEBora, |. c. 1852, p. 6.

CrPHALON anteriorly depressed, without a rostrum, having
the superior antennee affixed to the apex, about one-third the
length of the animal, and inferiorly ciliated; inferior antennee
slightly longer than the superior: gnathopoda subequal,
hairy: first two pairs of pereiopoda with long stylate dactyla,

506 APPENDIX.

third and fourth pair having the basis round, and the dactylos
short, curved, and posteriorly directed; fifth pair having the
basis long and narrow, and the propodos and dactylos almost
rudimentary : posterior pair of pleopoda long, with two sub-
equal rami, ciliated, on the inferior margin; telson two-lobed.

This species was first taken off the coast of Norway, in
1854. It has since been taken in England, off 'Tynemouth,
off the Holy Island, and in the Shetlands, by the Rev. A. M.
Norman.

APPENDIX. 507

AMPHAIPODA. PHOXIDES.
NATATORIA. (Vol. I. p. 170.*)

MONOCULODES LONGIMANUS, N.S.

Specific character. Dorsal surface slightly carinated. First pair of
gnathopoda long and narrow, resembling the second pair.

Length, about one-fifth of an inch.

Tus species differs from those previously described in
having the first pair of gnathopoda long and narrow, and
in fact developed more nearly on the type of the second pair.
The dorsal surface is slightly carinated. It was sent to us
from Banff by Mr. Edward. We have two specimens, both
of which have the superior antennz wanting, while in one
the inferior antenne are short, and in the other they are long
and slender. We consider the latter to be the male form,
and the former the female.

508 APPENDIX.

AMPHIPODA. PHOXIDES,
NATATORIA, (Vol. I. p. 178.*)

KROYERA BREVICARPA, N.S.

Specific character. Superior antennze short ; inferior as long as the entire
animal. Second pair of gnathopoda chelate, with the lower angle of the
carpus not extending along the inferior margin of the propodos.

Length, about one-sixth of an inch.

Tuis species differs from those previously described in
having the superior antennse short and thickly furnished with
auditory cilia; the inferior antennee being as long as the
animal; the first pair of gnathopoda, with the propodos,
ovate, having the palm armed with three or four obtuse
denticles and two rows of hairs, and defined by a strong
spine; the anteriorly produced carpus also terminating in a
strong spine; and in having the second pair of gnathopoda
chelate, with the antero-inferiorly produced angle not extended
along the inferior margin of the propodos.

It was taken at Banff by Mr. Edward.

APPENDIX. 509

AMPHIPODA. LYSIANASSIDES,
NATATORIA. (Vol. I. p. 118.***)

Genus—LEPIDEPECREUM.

Generic character. Cephalon having the orbital or intra-anten-
nal process considerably developed and produced. Pereion well
developed. Pleon having the last four segments very short. Eyes
not made out; supposed to occupy the intra-antennal process ;—
superior antenne having the upper surface of the first two joints of
the peduncle considerably produced anteriorly, having no secondary
appendage. Inferior antenne posterior to the superior. Mandibles
furnished with a biarticulate appendage. First pair of gnathopoda
moderately robust, subchelate. Second pair feeble and chelate or
subchelate. Posterior pair of pleopoda short, biramous. Telson —?

LEPIDEPECREUM CARINATUM, N.S.

Specific character. Body dorsally carinated. Segments subequal. Fourth
and fifth segments of pleon produced into a tooth. Gnathopoda minute and
slender.

Length, one-fifth of an inch.

Tur cephalon has the intra-antennal process produced
anteriorly as far as the infero-distal extremity of the first joint

510 APPENDIX.

of the peduncle of the superior antenne, when the latter is
deflected in the same line. The segments of the pereion
and the anterior three of the pleon are subequal; the three
posterior segments of the pleon very short; and the fourth
and fifth dorsally produced into a tooth.

The superior antenne have the first joint of the peduncle
thick, and as long as the cephalon, with the upper surface
anteriorly produced into a scale-like process, quite as far as,
if not beyond, the distal extremity of the third joint of the
peduncle; second joint with the upper surface anteriorly
produced like the first; third not so produced; flagellum
short, consisting of four or five articuli. The inferior antenne
are short, having the peduncle longer than the flagellum ;
flagellum consisting of four articuli; and the whole organ
not reaching beyond the extremity of the first joint of the
peduncle of the upper antenne. The first pair of gnatho-
poda have the propodos but little longer and not broader than
the carpus; anterior and posterior margins subparallel; palm
slightly oblique, and defined by an acute tooth; dactylos short
and curved. The second pair of gnathopoda have the propodos
shorter than the carpus, anterior and posterior margins curved,
sub-parallel; digital process short and conical; dactylos not
longer than the digital process of the propodos, conical, curved.
The pereiopoda are short, robust, subequal last pair slightly
the longest; third pair having the coxa quadrate, half as deep
as that of the preceding ; basos circular, as deep as the coxa;
meros posteriorly produced to a thin angular plate. The
fourth and fifth pairs differ from the third in being less robust
and slightly longer. The rami of the three posterior pairs of
pleopoda short. ‘The telson has not been made out.

Taken at Banff by Mr. Edward, associated with Anonyx
longicornis, with which it is very closely allied, being perhaps
a young female.

ANONYX LONGICORNIS (vol. i, p. 91).—The absence of a secon-
dary appendage to the upper antenne must separate it from
the genus Anonyw, to which it is assigned in the body of the
work. We therefore arrange it in the present genus in
consequence of its near affinity with the last species.

APPENDIX. 51]

AMPHIPODA. GAMMARIDES.
NATATORIA. (Vol. I. p. 259.)

UU
FE) ee Neen OK,
oy GJ i

Genus—NICIPPE. (Lruzelius.)

Nicippe. Bruzetius, Skan. Amph. Gam. p. 99. Spence Bars, Cat. Amph.
B: M. pais.

Generic character. Animal generally robust. Segments of the
pereion subequal, the three anterior of the pleon slightly longer,
increasing posteriorly. Cephalon nearly as long as the first two seg-
ments of the pereion. Superior antennz longer than the inferior,
and furnished with a small secondary appendage. Coxa moderate,
subequally deep. Gnathopoda subequal, subchelate. Two posterior
pairs of periopoda considerably longer than the preceding. Posterior
pair of pleopoda biramose. Telson simple; deeply cleft.

NICIPPE TUMIDA.

Specific character. Superior antenne nearly half the length of the body,
with a small three-jointed secondary appendage. Upper antenne rather
shorter. Gnathopoda subequal, with the propodos elongate-ovate. Three
posterior pairs of pereiopoda gradually elongated.

Length, half an inch.

Nicippe tumida. Brouzutius, Skand. Amph. Gam. p. 99, fig. 19. Spence
Barts, Cat. Amph. B. M. p. 374.

Fourta segment of the pleon having the posterior margin
furnished with two smali lateral teeth on the dorsal surface.

512 APPENDIX.

Eyes not recognizable in specimens that have reached us.
Superior antenne longer than the inferior, having a small tri-
articulate secondary appendage; inferior antennse having the
peduncle longer than the peduncle of the superior. Gnatho-
poda subequal and similar, having the inferior margin and
palm furnished with long cilia. Dactylos long and slender.
First two pairs of pereiopoda subequal and of moderate
length ; third pair not longer than the preceding ; fourth pair
about one-third as long again; fifth pair longer than the fourth;
posterior pair of the pleopoda subfoliaceous and ciliated.
Telson single, but cleft deeply, so as to appear double.

We have received one or two specimens from Mr, Jeffreys,
who dredged them off the Shetlands.

APPENDIX. 5138

AMPHIPODA. GAMMARIDES.
NATATORIA. (Vol. 1. p. 847.*)

Genus—CHEIROCRATUS. (Norman.)

Trans. Nat. Hist. Soc. Northumberland and Durham, vol. i. p. 12.

Generic character. Long and slender. Segments of the pereion
and pleon subequal. Eyes round. Antenne subequal; peduncle
of the superior shorter than the peduncle of the inferior; furnished
with a secondary appendage. Mandibles having a long appendage.
Gnathopoda unequal: first pair simple; second pair long, large,
and robust. Posterior pair of pereiopoda longer than the preceding.
Posterior pair of pleopoda long and unibranched. . Telson double.

CHEIROCRATUS MANTIS.

Specific character. Dorsal surface of the fourth segment of the pleon
produced posteriorly into a short central and a long lateral tooth on each side,
the space between being occupied by a long cilium. Fifth segment resembling
the fourth, but having the teeth less important and the cilium absent.

Length, nearly half an inch.

Cheirocratus mantis. Norman, op. cit. vol. i. p. 13, pl. vii. figs. 14, 15.

THE superior antenne about the length of the cephalon
VOL. Il. Vy 1G

514 APPENDIX.

and the four anterior segments of the pereion. Flagellum
about the same length as the peduncle. Secondary appendage
small. The inferior antenne are a little longer than the supe-
rior, the peduncle being about three-fourths of the antenne.
The first pair of gnathopoda are cylindrical, having the poste-
rior margin of the carpus and propodos thickly ciliated ;
carpus as long as the propodos, tapering; dactylos apical,
straight. The second pair of gnathopoda are long; propodos
ovate; palm oblique, defined by a strong tooth, armed near the
base of the dactylos with a double dentated tubercle, and
near the middle with three teeth, of which the anterior is the
largest; dactylos short, shorter than the palm, curved and
simple. The three posterior pairs of pereiopoda have the
basos narrow and the entire appendage increasing posteriorly
in length; the posterior pair of pleopoda having the ramus
nearly three times as long as the peduncle. The telson is
tipped with strong cilia.

This species was first taken and described by the Rey.
A. M. Norman, from a single specimen dredged in deep water
off Holy Island. We have since received it, through Mr.
Dawson, from the coast of Aberdeenshire.

APPENDIX. 515

AMPHIPODA. GAMMARIDES.
NATATORIA, (Vol. I. p. 410.*)

MEGAMGRA MULTIDENTATA,. (Norman MSS.)

Specific character. Body long and slender. Second segment of pleon with
three teeth on the middle of the posterior margin ; third segment with four ;
fourth, fifth, and sixth segments with two similar teeth.

Length, six-tenths of an inch,

Tue body is long and slender, with the segments subequal ;
the second segment of the pleon haying a central, and on
each side a lateral tooth on the posterior dorsal margin; third
having a central and two lateral teeth on the dorsal margin;
the three following segments without a central, but possessing
on each a lateral tooth, at the base of which a strong hair or
spine exists.

The eyes are round and black. The superior antenne are
half the length of the animal, and the peduncle is half the
length of the antenne. The first joint is as long as the
cephalon ; the second joint is a little longer and slighter than
the first; the third is short. The articuli of the flagellum
are as long again as broad ; the secondary appendage consists
of five articuli. The inferior antenne are about half the length
of the superior; the peduncle extends to the extremity of the
second joint of the peduncle of the superior. Olfactory denticle

LL 2

516 APPENDIX.

long and prominent. Third joint of the peduncle short and
stout, and furnished at the infero-anterior angle with a strong
tooth and a few hairs. Fourth and fifth joints long, slender, and
subequal. The flagellum consists of eight articuli. First pair
of gnathopoda slender; propodos shorter and not broader
than the carpus, furnished with numerous and long hairs;
dactylos short and impinging closely on the palm. Second
pair long and well developed; carpus distally dilated: pro-
podos subeonfluent with the carpus, long, broad ; inferior and
superior margins subparallel; palm oblique, armed near the
centre with a broad flat-headed tubercle, furnished with a few
hairs, slightly posterior to which is a double-cusped process,
or strong tooth, between the two points of which the apex of
the dactylos impinges; and at the infero-anterior angle are
two prominences, carrying one or two strong straight spines:
the dactylos is very robust, abruptly curved, sharp at the point,
and shorter than the palm. Posterior pair of pleopoda (want-
ing). Telson double-lobed ; each lobe surmounted by a single
spine.

Hab.—Guernsey, where it was taken by the Rey. A. M.
Norman,

APPENDIX. Hy

AMPHIPODA. PODOCERIDES.
DOMICOLA, (Vol. 1. p 491.*)

Genus—UNCIOLA.
Unciola. Say, Journal Acad. Nat. Sci. Philad. i. p. 389. Epwarps,
Ann. des Sc. Nat. t. xx. p. 383. Hist. des Crust. iii.
p. 69,
Glauconome. Kroyur, Nat. Tidsk.i. p. 501. Sprnce Bartz, Cat. Amph.
B. M. p. 278.

Generic character. Long and slender, not much compressed.
Segments subequally long, increasing in length a little posteriorly
to the third segment of the pleon. Eyes small and round. Superior
antenne furnished with a slender flagellum and a small secondary
appendage. Inferior antennz subequal with the superior. Gnatho-
poda robust: first pair subchelate ; second pair not subchelate.
Pereiopoda long and slender; coxx small, subequal; basos of the
three posterior pairs but slightly, if at all, enlarged. Posterior pair
of pleopoda having but a single branch, and that almost rudimentary.
Telson single, flat.

518 APPENDIX.

UNCIOLA LEUCOPES.

Specific character. Upper antenne nearly half the length of the animal.
Secondary appendage minute. Gnathopoda fasciculated. Terminal pleopoda
armed with short strong spines.

Length, one-third of an inch.

Unciola leucopes. Kroyir, Nat. Tidsk. i. 491, pl. 7, fig. 2. Spmnce Bars,
Cat. Amph. B. M. p. 279.

planipes. Norman, Trans. Nat. Hist. Soc. of Northumberland and
Durham, vol. i. pl. vii. figs. 9—18.

9

Tue eyes are small. The antenne are subequal, the superior
pair nearly half the length of the animal: first joint of the
peduncle rather longer than the cephalon; second rather
longer than the first; the secondary appendage being small.
The inferior antenne are shorter than the superior, having
the peduncle rather longer than the peduncle of the superior.
The gnathopoda are armed with fasciculi of hairs ; first pair
having the propodos ovate, with the palm waved and imper-
fectly defined, furnished with several fasciculi of long cilia;
dactylos serrated along the inner margin. Second pair having
the carpus almost as long again as the propodos ; propodos
tapering; dactylos apical, minute. The pereiopoda are long,
slender, and cylindrical. The pleopoda have the antepenultimate
pair Jonger than the penultimate ; the penultimate longer than
the ultimate; ultimate scarcely reaching beyond the telson.
Telson circular.

This species was taken by the Rev. Mr. Norman off Holy
Island, on the coast of Northumberland and Durham, and
named by him U. planipes in the Transactions of the Natural
History Society of Northumberland and Durham. We had
previously received it from the Haaf Ground, Shetland. We
believe, however, that the species probably is identical with
Kroyer’s Greenland species, the distinction between the two
arising from omissions in description and figure rather than
any clear variation of character.

APPENDIX. 519

AMPHIPODA. HYPERID.
HYPERINA. (Vol. JI. p. 18.*)

HYPERIA TAURIFORMIS, N.S.

Specific character. Antenne very short. Both pairs of gnathopoda with
the proximate margins of the propodos and carpus strongly serrated, as well
as the dactylos of the second pair.

Length, four-twentieths of an inch.

Tue antenne in this species are very short. The inferior
angle of the carpus is anteriorly produced in both pairs of
gnathopoda, and the proximal margins of the propodos and
carpus are strongly serrated, as also is the dactylos of the
second pair.

Dana established the genus Tuuria for the reception of
those species of Hyperia that have the antero-inferior angle
of the carpus of both pairs of gnathopoda so far anteriorly
produced as to extend to the extremity of the propodos, thus
forming a tolerably perfect but compound chelate organ.
But so gradual is the development of this process from one
species to another, that we can see no clearly defined limit
where one genus may commence and the other end.

We have chosen a specific name for our new species which
indicates its affinity with Dana’s proposed genus.

The animal above described was taken at Banff by Mr.

- Edward.

520 APPENDIX.

AMPHIPODA. HY PERIDA.
HYPERINA. (Vol. IT. p. 18.**)

HYPERIA PREHENSILIS, N.S.

Specific character. Superior antenne about the length of the head. Both
pairs of gnathopoda with the carpus and propodos simple. Three hind pairs
of pereiopoda subprehensile at the tips.

Length, three-twentieths of an inch.

Tuis species differs from H. tauriformis next described in
having longer antennze, the proximal margins of the carpus
and propodos of both pairs of gnathopoda not serrated, and
in haying the propodos of the last three pairs of pereiopoda
inferiorly produced and armed with short strong cilia. This
gives a prehensile character to the last three pairs of pereio-
poda that we have not recognized in other species.

Taken at Banff, by Mr. Edward, with the preceding species.

APPENDIX. 521

AMPHIPODA. AYPERIUDA.
HYPERINA. (Vol. II. p. 18.***)

HYPERIA CYANEA.

Specific character. Superior antenne very short; flagellum scarcely longer
than the peduncle. Gnathopoda subequal and nearly alike ; first pair short,
with the propodos subovate ; superior margin arcuate, inferior straight. Dac-
tyla of three posterior pairs of pereiopoda long, sharp, and furnished with a
bunch of cilia in the middle.

Length, rather more than three-twentieths of an inch.

Talitrus cyanec. Sapine, Appendix to Parry’s Voyage, pl. i. figs. 12—18.
Metoechus cyanee. Epwarps, Hist. des Crust. iii. p. 78. Wuitr, Cat.
Brit. Crust. (Brit. Mus.) 1847.

Hyperia cyanee. Spunce Bare, Cat. Amph. p. 294, pl. 48, fig. 10.

A specimen of Hyperia has been sent to us by Mr. Edward,
of Banff, that we take to be a variety of this species: it differs
in having the antennee much less developed than those in
the typical specimens. It looks like a young H. Galba, with
rudimentary antennz, but one of the specimens sent to us
has the incubatory pouch of the adult female fully developed,
so that we cannot mistake it for a young animal. Mr.
Edward says that he has never taken this species in a Medusa,
and that he has frequently found it on the shores of the
Moray Frith in December, January, and February, that is,
at a time when the Meduse are not on the coast.

522 APPENDIX.

AMPHIPODA., HYPERIID&.
EEE TEEN (Vol, HL. p. 18.****)

Genus—THEMISTO. (Guerin.}

Themisto. GutRiIn Méinevittn, Mém. de la Soe. d’Hist. Nat. de Paris, iv.
1828. Epwarps, Ann. des Sci. Nat. xx. p. 393. Hist. des
Crust. ili. p. 84. Spence Barr, Cat. Amph. Brit. Mus. p. 3il.

Generic character. Cephalon transversely ovate. Perion not dis-
tended. Pleon slender. Eyes occupying the entire cephalon, dor-
sally separated. Antenne short; superior pair having the flagellum
cylindrical and uniarticulate ; inferior pair more slender, and having
the flagellum multiarticulate. Mandibule having an appendage.
First pair of gnathopoda short, with the inferior angle of the carpus
not anteriorly produced; second pair having the inferior angle of
the carpus anteriorly produced. IT irst two pairs of the pereiopoda
having the carpus dilated, the propodos cylindrical, and the
dactylos inflected back against the carpus. Third pair of pereiopoda
extremely long, being twice the length of the preceding pair, and
armed anteriorly with a series of comb-like sete. The last two pairs
of pereiopoda not half the length of the preceding. Three poste-
rior pairs of pleopoda being long. ‘Telson single.

APPENDIX. ae

THEMISTO CRASSICORNIS.

Specific character. Superior antenne very short, thick, biarticulate, fur-
nished along their under surface with numerous auditory cilia; inferior antennze
with a flagellum composed of one short and one long joint. First two pairs
of pereiopoda having the carpi subovate, smooth, and unarmed along the
inferior margin.

Length, half an inch.

Themisto crassicornis. Kroyrx, Gronl. Amfip. p. 67, pl. iv. fig. 17.
Epwarps, Hist. des Crust. t. iii. p. 85. SPENCE
Bate, Cat. Amph. B. M. p. 318, pl. i. fig. 12.

Tue first two segments of the pereion are shorter than the
rest, which are subequal. The superior pair of antennee have the
peduncie short, the flagellum uniarticulate, curved downwards
at the extremity, and furnished along the inferior margin, for
about two-thirds of its length, with auditory cilia. The inferior
pair consist of a peduncle, of which two segments are visible,
and a long slender multiarticulated flagellum. The first pair
of gnathopoda are very short, not having the carpus anteriorly
produced. The second pair of gnathopoda are not larger than
the first, but having the inferior angle of the carpus anteriorly
produced. The first two pairs of pereiopoda resemble each
other ; the second pair is slightly the larger, having the
meros and carpus broadly distended, the latter fringed along
the inferior margin with a row of very fine short cilia, and a
few long equidistant solitary hairs; propodos and dactylos
reduced in character to a biarticulate joint, that bends back to
form a prehensile organ with the carpus. The third pair of
pereiopoda are very long, quite as long again as the next suc-
ceeding pairs, having the propodos and carpus subequal in
length, and the former furnished on the anterior margin with
a comb-like row of fine teeth; dactylos short and slender.
The two last pairs of pereiopoda are about half the length of
the third pair. The posterior pair of pleopoda is long and
simple. The telson is short and dorsally flat, having a central
process on the under surface that lies between the basal joints
of the posterior pair of pleopoda. Colour, orange.

This species has been recently sent to us by Mr. Edward,
who has taken several of different ages off the coast of Banff.

524 APPENDIX.

AMPHIPODA. HYPERUDA.
HYPERINA. (Vol, IL. p. 19.*)

Genus—VIBILIA.

Vibilia. Epwarps, Ann. des Sci. Nat. t. xx. p. 386. Hist. des Crust.
t. lii. p. 72. Spunce Batu, Cat. Amph. B. M. p. 299.
Lanceola? Say, Proc. Acad. Phil. p. 317.

Generic character. Cephalon small. Pereion smooth, not dis-
tended. First two segments of the pereion short, the rest gradually
increasing in length. Segments of the pleon a little deeper than
those of the pereion. Eyes small. Antenne short; superior pair
terminating in a vertically compressed uniarticulate flagellum.
First pair of gnathopoda small, slender, cylindrical, having the infe-
rior angle of the carpus but little, if at all, produced; second pair
having the inferior angle of the meros and carpus considerably pro-
duced anteriorly. First two pairs of pereiopoda subequally long.
Third and fourth pairs longer than the preceding, subequal. Last
pair very short. Three posterior pairs of pleopoda, with the
peduncle long and the rami short and compressed. Telson single.

VIBILIA BOREALIS, N.S.

Specific character. Cephalon not anteriorly produced. Pereion with the
segments gradually enlarged. Flagellum of upper antenne flat, with two
rows of cilia on the internal surface. Last pair of pereiopoda minute.

Length, seven-twentieths of an inch.

APPENDIX. 525

Tue pereion has the first segment short, each segment
gradually increasing in length posteriorly to the third segment
of the pleon. The eyes are vertically of an oblong oval form.
The first pair of antennee have the flagellum vertically and
longitudinally flattened, the inner surface being furnished
with two central rows of cilia, the cilia in one row being
directed upwards, and in the other downwards. The second
pair of antenne are slender, cylindrical, not longer than the
superior, articulations variable. The gnathopoda are subequal,
small. The first two pairs of pereiopoda robust, subequal.
The third and fourth pair subequal, longer than the preceding,
but not more than one-third; propodos having the anterior
margin fringed with fine rows of short teeth. The posterior
pair of pereiopoda are scarcely half the length of the pre-
ceding. The pleopoda are subequal, reaching beyond the
extremity of the telson, having the approximate margins only
of the rami fringed with short strong spines. Colour reddish
orange spotted with black.

Hitherto the species of this genus have been taken only
as pelagic in tropical or subtropical latitudes. It is an
interesting fact that this species should have been taken off
the coast of Banff, from whence it was sent to us by that very
successful observer, Mr. Edward, who in writing says: “I can
say little as to its habits. I took eleven, and kept a few alive
for a short time, but observed nothing in their manners beyond
that which may be seen in the majority of species. I supplied
them with plenty of sand, and also a few marine plants, but
they neither seemed to be burrowers nor climbers, as they
never went into the one nor appeared to care for the other.
They, however, swam a little. ‘This they do somewhat after
the manner of Callisoma crenata ; or, in other words, they rise
gradually from the bottom until they reach the top; then
putting on more power, they dash round and round the vessel.
With close observation I observed that the superior antennc
were kept pretty well up and very widely apart, whereas the
inferior were always directed downwards. All the legs were
kept doubled up. I never saw them stretched out. They
would then sink once more to the sand at the bottom. Here
they would rest, sometimes a few minutes, sometimes longer,

526 APPENDIX.

when they would again repeat their voluntary evolutions.
They did not, however, always rise to the surface. ‘The
journey was sometimes performed about midwater. They
are, when alive, a most beautiful coloured species, variegated
not unlike Urothoé elegans, and rivalling that animal in bright-
ness of tints. I took one, however, that was all over a most
brilliant red. I have been told that this species has never
been found outside the Medusa. However this may be, all
mine were. And what appears to be more extraordinary is,
that, comparatively speaking, we have had no Meduse here
this season (1865). During the months of July, August, and
September I have seen them, generally, by hundreds and
thousands. All that I have this year observed have been
three.” Mr. Edward also informs us that he has seen speci-
mens of these crustaceans thrown on the shore in extraordinary
large quantities. After a storm one night, he saw them form-
ing a band an inch and a half broad to an inch and a half
deep, for thirty yards along the beach.

APPENDIX. 527

SUPPLEMENTAL NOTES.

ALLORCHESTES NILSSONII.
(Vol. I. p. 40.)

Tue females of this species, and probably of all in the genus,
have the second pair of gnathopoda, slightly larger than
those of the first pair.

Genus— MONTAGUA.

(Vol. I. p. 53.)

Dr. Camil Heller (Beitrage zur naheren Kenntniss der
Amphipoden des Adriatischen Meeres ; Denkschr. Ak. Wiss.
Wien, xxvi. p. 18) states that this genus is identical with
Probolium of Costa.

PHOXUS HOLBOLLI.
(Vol. I. p. 143.)

Mr. Edward has sent us from Banff a specimen that cor-
responds with this species, except in having longer inferior
antennee.

We consider it the male form.

PHOXUS PLUMOSUS.
(Vol. I. p. 146.)

A specimen of this genus has been forwarded to us from
Banff, by Mr. Edward, that corresponds with this species in
general character, except in having very much longer lower
antennee, as well as a long plumose posterior pair of pleopoda.

We take it to be the male form.

528 APPENDIX.

GDICEROS PARVIMANUS.
(Vol. I. p. 161.)

Some specimens have been sent to us from the Shetlands
by Mr. Gwynn Jeffreys, and from Banff, where they were taken
by Mr. Edward, that so nearly correspond with this species,
that we think they must be the male form. They differ from
that described in having the upper antennee but little longer
than the peduncle of the lower; the lower antenne as long
as the entire animal; and the gnathopoda with hands some-
what larger, but scarcely equal to the “very large” hands as
described by Kroyer in his description of the genus.

KROYERA ARENARIA.
(Vol. I. p. 173.)

A specimen of Kroyera has been sent to us by Mr. Robert-
son, who found it in sand near low water in Kames Bay,
Milport. It differs from K. arenaria in having the inferior
antennee longer than the animal.

It may, as Mr. Robertson suggests, be the male.

ACANTHONOTUS OWENII.
(Vol. I. p. 232.)

We have no hesitation in referring this species to the Gam-
marus corniger of Fabricius,* whose specific name has long
priority over any of the other names quoted in the page
above referred to, and must consequently be adopted instead
of that employed by us. It is also identical with the Epimeria
tricristata of Signor A. Costa (Mem. di Real. Accad. Sci.
Napoli, i. tab. 2, f. 2, 1853).

ATYLUS GIBBOSUS.
(Vol. I. p. 248.)

Specimens of this species have been sent to us by Mr.
Robertson, who took them on three different occasions in
Kames Bay, imbedded in sponge on the valves of Pecten oper-

* Tter Norwag. d. 20 Aug.; Spec. Ins. i. p. 517 (1781); Mant. Ins. i.
p. 334 (1787) ; Ent, Syst. ii, p. 517 (1793).

APPENDIX. 529

cularis. From the position of the animals, they appear to
have remained in one place while the sponge grew round
them, and in some instances almost enclosed them. Mr.
Robertson remarks, ‘‘ It may be a nice point to settle whether
the sponge serves for shelter or for food.”

AMPHITHOE RUBRICATA.
(Vol. I. p. 416.)

This and all the species described in the pages from 416 to
493 belong to the section Domicola: the left-hand heading,
‘“ Amphipoda Natatoria,” at the commencement of each genus
and species, consequently requires correction.

COROPHIUM LONGICORNE,
(Vol. I, p. 494.)

With reference to the passage quoted by us from M. Quatre-
fages, Mr. Robertson writes to us: ‘(In February last I had
an opportunity of seeing C. longicorne at Dunbar, both at the
mouth of the Clyde and in the bays, where there was no admix-
ture of fresh water, at high water, having little doubt but that
it is to be found on our shores all the year round. I have
again seen it burrowing, which it does rather sluggishly. In
this operation it brings the points of the long antenne
together, and pushes them into the mud; the fore-feet assist
in widening the hole, and in turning the mud sideways; the
hind-feet throw it backwards ; the tail is carried at an angle
downwards, which it presses against the mud, and forces itself
forwards. My experience leads me to think that they do not
burrow very deeply. I find them plentifully in the soft
surface mud, but when I remove that away to the depth of
about three inches, I have not found them in the firmer sub-
soil.”

Mr. Robertson has also kept them with Annelids in the
same vessel until they died, without perceiving them attempt-
ing to touch the worms.

VOL. Il. M. M.

5380 APPENDIX.

According to the rules of nomenclature recently laid down
by the British Association for the Promotion of Science, the
names of the sub-families adopted in this work should
uniformly terminate in ina instead of ides.

The Annals of Natural History for December, 1868 (Ser. 4,
vol. ii., p. 411—, and plates 21, 22, and 23), contain a Memoir
by the Rev. A. F. Norman, in which the following species of
Sessile-eyed Crustacea are described and figured :—

1. Haploops tubicola Lilljeb. (See our Vol. ii. p. 506.)

2, Tessarops (nov. gen. Norm.) hastata Norm. (? Tiron
acanthurus Lilljeb. ? Syrrhoe bicuspis Goes.) Aberdeen
coast.

. Nicippe tumida Bruzel. (See our Vol. ii. p. 511.)

. Eriopis elongata Bruzel. Sound of Skye.

. Meera Loveni Bruzel. Sound of Skye.

. Mera Batei Norm. (See our Vol. ii. p. 515.)

. Helleria (nov. gen. Norm.) coalita Norm. Shetland,
Moray Firth, and Firth of Clyde.

8. Microprotopus (noy. gen. Norm.) maculatus Norm. To-

bermory, Isle of Mull.

I Om oP OO

9. Cirolana truncata, n. sp. Norm. St. Magnus Bay, Shetland.
10. Anilocra Mediterranea Leach, Desm. In rock, pools at
Herm.

531

ALPHABETICAL INDEX.

The sectional and family names are printed in capitals.

The specific names are arranged alphabetically under each generic name.
The synonymical names of the genera are enclosed in brackets.

ABERRANTIA (Amphipoda) .
ABERRANTIA (Isopoda) .

Acanthonotus .
Owenli .
ABga *

bicarinata .

.

monophthalma .

psora 5
tridens ,

Aicip zs

AMgina . :

JPRO-SPIRANTIA

Allorchestes
imbricatus
Nilssonii .

(Amathia) 0

Amathilla
Sabini :

Ampelisca .
Belliana ,
Gaimardii .
leevigata

AMPELISCIDES .
Amphilochus ,

manudens.
AMPHIPODA A
(Amphithoé) .

Amphithoé
albomaculata
Gammaroides
littorina ,
rubricata .

ANCEIDE.

Anceus .

i. 232 & ii.

Edwardii (Praniza) .
fuscata (Praniza)

Halidaii .

maculata (Praniza)

maxillaris .

1
il

i,

ii.
ii.
ii.
ii.

age
28
116
231
528
276
278
286
283

(Anisocheirus) .
(Anisopus) -

Anonyx ,
ampulla .
denticulatus
Edwardsi ,
Holbolli .
longicornis
longipes .
minutus .
obesus 5
Plautus ,

Anthura .
gracilis,

ANTHURIDE

Aora ;

gracilis.
Apseudes .
Latreillii .
Talpa
AQUASPIRANTIA
(Araneops) .
AROTURIDH.
Arcturus . :
gracilis.
intermedius
longicornis
(Armadillidium)
Armadillo :
vulgaris .

ASELLIDD =

Asellus . c
aquaticus ,

Atylus . A
bispinosus .
gibbosus .
Swammerdamii

Bathyporeia .
pelagica .

=) is
ey uit
oped
i

a
arenes
534
i, 91 Nii
1
ak
a ale
saute
eile
ie
sete
i.

oy jal
all
oy Aa
weeds
i.
alls
ii

ii

ii

ii.

ii,

il.
AL
ii

A att
a
rege
248 & i.
mals
spre
i,

532

Bathyporeia pilosa
Robertsoni
(Bellia)
Bopryripa
Bopyrus .
Squillarum
Calliope
Fingalli
grandoculis
leviuscula
Ossiani .
Callisoma
crenata
Campecopea
Cranchii
hirsuta
Caprella .
acanthifera
acutifrons .
vequilibra .
hystrix
linearis
lobata
spinulata .
tuberculata
typica
CAPRELLIDZ
(Ceradocus)
(Cerapodina)
Cerapus
abditus
difformis
Cheirocratus
mantis
Chelura
terebans
CHELURID
Cirolana .
Cranchii
spinipes
Conilera .
cylandracea
CoROPHIID.®
CoROPHIIDES
Corophium
Bonellii
crassicorne
longicorne
Crangonyx

IN DEX.
Page
i. 304 | Crangonyx subterraneus
i, 307 | Cratippus
Si tenuipes .
. 210 | (Cratophium)
. 214 | (Crossurus)
ii. 218 | (Cryptoniscus) .
. 258 | Cryptothiria
. 263 balani
i. 265 pygmea
. 259 | Cramps
i. 261 | Cyamus . 3 ;
oe a?) Ceti
. 120 gracilis
43 ovalis
436 Thompsoni
434 | (Cymadusa)
49 | Cymodocea i :
65 emarginata
60 truncata . ‘
71 | Cyrtophium
63 Darwin .
52 | Danaia
57 dubia
74 | Darwinia
68 compressa .
75 | Dercothoé .
85 punctatus .
835 | Dexamine
452 spinosa
452 tenuicornis
455 Vedlomensis
457 | Domicona
513 | Dryope :
513 crenatipalmata .
205 irrorata
503 | Dulichia .
501 falcata
294 porrecta
296 | DuLicHup”
299 | Dynamene : .
302 Montagui .
304 rubra
414 viridis
478 | (Dyopedos)
492 | Hiscladus.
497 longicaudatus
499 | (Elasmopus)
529 | Entoniscus
326 Porcellanz

Se aL et a OO rr Pe Pa
See Reig Saleh Scag acai aie Aare le oan cons yearn aE iod eC pe RE od ee

i. _- . _. .
ee me oe Ge Ss ES Ee Es es

(Ericthonius)
(Eupheus)
Eurydice .
pulchra
Eurystheus
bispinimanus
erythrophthalmus
Eusirus ‘
Helvetie .
(Galanthis)
Gammarella
brevicaudata
Normanni.
GAMMARIDE
GAMMARIDES
GAMMARINA
Gammarus
campylops .
dubius
Edwardsii .
locusta
maculatus.
marinus
nolens ;
pulex
tenuimanus
(Gnathia).
Gossea 3
microdeutopa
Grayia
imbricata .
Gyge 5 :
Galathex .
Hippolytes
Haploops .
tubicola
(Hemioniscus) .
(Hiella)
Hyperia .
cyaneze
Galba
oblivia
prehensilis
tauriformis
Hyprriupa
HyPrrIna
Idotea
acuminata .
appendiculata

INDEX.

Page
i. 452 | Idotea emarginata
ii. 144 linearis
ii. 3807 parallela
ii. 310 pelagica
i, 353 tricuspidata
i. 357 | Iporzpa.
i, 354 | Ione ‘i :
i. 266 thoracica .
i, 267 | (Iphimedia)
i. 45 { Iphimedia .
i, 329 Eblane ,
i. 330 obesa °
i. 333 | Isa 5
ih tll Montagui .
i. 235 | (Ischyrocerus) .
i. 11 | Isopopa
i. 866 | (Itea) .
i. 875 | Joora
i. 397 albifrons
i. 386 Nordmanni
i, 378 | (Jeridina)
i. 399 | Janira A
i. 370 maculosa .
ii. 19 | (Jassa)
i, 888 | Kroyera .
i. 384 altamarina
ii, 170 arenaria
i. 276 brevicarpa
i. 277 | LmMopiIpopa .
i, 151 | (Laetmatophylus)
i, 152 | (Lalaria) .
ii, 223 | (Larunda)
ii, 225 | (Lembos) . :
ii, 230 | Lepidepecreum .
li. 506 carinatum .
ii. 506 | Leptaspidia
i, 257 brevipes
ii. 10 | (Leptocheirus) .
ii, 10 | Leptochelia
lie 521 Edwardsii .
ii. 12 | (Leptomera)
ii. 16 | (Leptothoé)
ii. 520 | Lestrigonts
ii. 519 exulans
Rite Ee Kinahani .
ii. 1 | Leucothoe
li. 376 articulosa .
li. 394 furina

i. 396 | (Leucothoé)

534

LIBERATICA
Ligia :
oceanica
Liljeborgia .
pallida .
Shetlandica
Limnoria .
lignorum .
(Liriope) .
(Liriopsis)

(Lonchomerus) .
(Lycesta) .
Lysianassa :
Atlantica .
Audouiniana
Costze
longicornis
LyYSIANASSIDES .
Megameera
Alderi
brevicaudata
longimana.
multidentata
Othonis .
semiserrata
Melita . -
gladiosa
obtusata .

palmata .
proxima .
(Microcheles) .
(Microdeutopus)

Microdeutopus .
anomalus .
fasciculatus
gryllotalpa
versiculatus
Websteril .

(Meera) .

Mera . “
grossimana

(Metoechus) .,

Monoculodes .
carinatus .
longimanus
Stimpsoni ,

Montagua
Alderi
clypeata

INDEX.
Page
ii. 313 | Montagua marina . es
. ii, 442 monoculoides . E
ii. 444 norvegica . ii
i, 202 pollexiana. rae £5
i. 203 | Munna ii
i, 206 Kroyeri . : ii
li, 3849 Whiteana . il
ii. 351 | Nesa , il
My 257 bidentata . Pett
ii. 257 | NavaTorIA Ie
i, 279 | (Naupredia) ii.
i, 269 | Nicea 3 Te
a Age: Lubbockiana i
i. 82 | Nicippe ii
1,0 279 tumida i
i. 74 | Niphargus
15: 386 aquilex
effi fontanus
i. 400 Kochianus.
. Ji. 407 | Neenia
i. 409 excavata
» i. 408 rimapalmata .
aod tuberculosa
+ 1 405 undata ;
i. 401 | Normazra (Amphipoda)
i. 335 | Normaxra (Isopoda) . li
i, 346 | (Nototropis) . i.
i, 341 | Qdiceros . ; ee
a i SEM parvimanus i. 161 & ii.
- i. 344 | (Oliska 2) ii.
i, 217 | Oniscipm. li
i. 287 | (Oniscoda) : il.
i, 287 | Oniscus li.
i. 293 asellus ii
i. 295 fossor : ii.
. i, 289 | Opis ; ii.
Smee 295) leptochela . ii
5 iy PAUL quadrimana il.
i. 335 | Orchestia : i.
i. 348 brevidigitata ii.
Pee: bcs!) Deshayesii ole
158 0 littorea sig At:
co ie IGE: Mediterranea 5 ie
- i. 165 | Orcuestips A aie
507 & ii. 527 | Otus : ; vy tae
aby ASKS: carinatus . i
- i. 53 | (Panope) . A oll
i. 61 | Paranthura F li
li. 499 Costana - Ae at

PARASITICA
Paratanais
forcipatus .
rigidus ,
Pereionotus
testudo
Phedra . 5
antiqua . :
Kinahani .
Pherusa . ; ;
bicuspis .
fucicola
Philoscia .
Couchii .
Muscorum
Philougria 4
Tipariays sy
rosea
vivida
PHOXIDES A 7
Phoxus

Holbolli . i:

plumosus . :
simplex , i
Phronima c :
sedentaria :
PHRONIMIDA ,
Phryxus . : ’
abdominalis :
fusticaudatus .
Galathee , .
Hyndmanni
longibranchiatus
Paguri , :
(Platophium) , .
Platyarthrus . 5
Hoffmannseggii .
(Pleonexes) . j
(Pleurocrypta) .
(Podalirius) . :

PopocrRIDES

Podocerus % P
capillatus . ;
faleatus . .
ocius q 5
pelagicus . ;
pulchellus
variegatus 7

Porcellio .

INDEX.
Page
ii. 209 | Porcellio armadilloides
(ty, UBY/ cingendus
li. 188 dilatatus .
Sok, Web leevis 5 é
Bk 2448 pictus : .
. i. 228 pruinosus . -
. i, 208 scaber ‘ 5
» i. 209 | (Praniza) . : :
i. 211 | Protella .
i, 252 phasma .
wei 259) |) Proto , : ;
i, 255 Goodsirii . C
ii, 448 pedata., ‘
. i. 452 | Protomedeia
li. 450 hirsutimana
li, 454 Whitei
ii. 456 | (Pseudophthalmus)
ii, 460 | (Ptilocheirus) . .
ii, 458 | (Pyctilus)
i, 138 | (Rhea)
- i. 189 | Rocinela .
143 & ii. 527 Danmoniensis
« i, 146 | Saurarorra
140 & ii. 527 | (Scopelocheirus)
» ii, 21 | Siphoncecetes . :
il, 23 crassicornis
5 tk, PAO typicus , :
5 bk, BY Whitei , :
ii, 234 | (Slabberina) .
. ii, 238 | Spheroma : 0
. ii, 249 curtum ., j
ii, 243 Hookeri , -
oP ls) 24.6 Prideauxianum .
fi, 240 rugicauda , .
. eh 279 serratum .
ii, 462 | SPHHROMIDE . C
. ii, 464 | SPHHROMIDEA .
. i. 416 | SrEGocEPHALIDES
ii, 232 | Stimpsonia 5
li, 649 chelifera
i. 415 | Sulcator .
i. 434 arenarius . ;
. i, 442 | Sunamphithoé .
5a Cede) conformata
. i, 450 Hamulus . A
. i. 447 | Talitrus . < c
i. 486 locusta .
. i, 489 | Tanara A
ii. 474 | Tanais

pie pee
me pte
.

oa ee So
ONE lah ani UST amentan ert Jaime wary 's

535

Page

. 486
. 490

42

284
285

189
429

if Wale)

536

Tanais Dulongii
vittatus
(Tauria) .
(Tetromatus)
Themisto ,
crassicornis
(Thersites)
(Typhis) .
Unciola
leucopes
Urothoe .
Bairdii
brevicornis

i.

ii

ii.

ate
eee
5) atk
i.

ii.

INDEX.

Page

129 | Urothoe elegans

. 125 marinus F

10 | Vacantra (Amphipoda)

125 | Vacantra (Isopoda) .

522 | (Vertumnus)

522 | Vibilia .

302 borealis
19 | (Westwoodia)

517 | Westwoodilla

518 ccecula

192 hyalina

193 | (Zeuxo)

198 | (Zia)

a

a ee eh ee

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